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The XXVII International Scientific Conference of Young Scientists and Specialists (AYSS-2023) will take place from 30 October to 3 November 2023 at the Laboratory of Nuclear Problems, Joint Institute for Nuclear Research (JINR, Dubna, Russia). This year the conference will be devoted to the 110th anniversary of Bruno Pontecorvo, outstanding physicist, who worked at JINR and made an invaluable contribution to the formation and development of modern neutrino physics.
Important! The participation in the conference can be held only in-person. Remote participation will not be available.
The Conference is held annually and attended by students, young scientists and specialists from scientific centers over the world. The selected talks will be recommended to be published in the refereed journal. Participation in the Conference will be confirmed by a certificate.
TOPICS
Within the framework of the Conference leading scientists will give lectures on the recent theoretical, experimental and applied investigations conducted all around the world with emphasis on the major results obtained at JINR. All participants are encouraged to submit abstracts on the following topics:
PARTICIPANTS
Students, young scientists and specialists under 36 years from all over the world are invited to participate in the Conference with oral and poster presentations.
SCIENTIFIC ADVISORY BOARD: | ORGANIZING COMMITTEE: |
Co-chairman: Grigory Trubnikov | Co-chairman: Liudmila Kolupaeva (DLNP) |
Co-chairman: Dmitry Naumov | Co-chairman: Alexander Nezvanov (FLNP) |
Grigory Shirkov (JINR Direction) | Ekaterina Kolosova (CPED) |
Aleksandr Cheplakov (VBLHEP) | Olga Korotchik (ICD) |
Olga Derenovskaya (MLIT) | Anastasia Kruglyak (FLNP) |
Grzegorz Kaminski (FLNR) | Vasilisa Lenivenko(VBLHEP) |
Sergey Kulikov (FLNP) | Mariia Mardyban (BLTP) |
Ekaterina Lesovaya (LRB) | Marina Mishchenko (DLNP) |
Valentin Nesterenko (BLTP) | Igor Pelevanyuk (MLIT) |
Evgeny Yakushev (DLNP) | Evgeniya Pronskikh (LRB) |
Dmitry Pugachev (FLNR) | |
Anna Rybakova (UC) | |
Veronika Smirnova (FLNP) | |
Rostislav Sotenskii (DLNP) |
THE WORKING LANGUAGE of the Conference is English.
THE REGISTRATION FEE for participation will be 7500 RUB (9000 RUB with VAT included) and will cover organizing expenses, coffee-breaks, the conference dinner and the social program event. For those who are not affiliated with JINR we will publish payment link on 1 October. Payments for participants affiliated with JINR will be carried out by internal cashless transactions.
FINANCIAL SUPPORT covering fee, local accomodation and partial travelling expenses can be provided for limited number of participants. The selection will be carried out on a competitve basis.
SECTIONS
During the conference, the participants will present their reports in one of the nine topical sections. Timeslot duration for sectional talks is 15 minutes and includes both presentation (12 min) and questions&answers (3 min). For poster session the size of poster should be A1.
In our work, we tried to identify the structural features of fragments from cast iron cauldrons of the medieval Golden Horde, as a representative of the products from the ancient iron casting process. We have selected two groups of iron-cast fragments from the Selitrennoye settlement in the lower parts of the Volga River and the Bolgar settlement in the central Volga region. Both settlements were capitals of the Golden Horde during the 13–15th centuries AD, but the difference in geographic location and historical area appoints them as manufacto-ry centers with modified technological approaches for casting and processing cast iron within the borders of one ancient state in a similar historical period. We expect a difference in the structural features of the internal structure of the fragments from cast iron cauldrons.
For this purpose, the method of neutron tomography was used, which is sensitive to light elements, has a noticeable difference in contrast between isotopes and a high penetrating effect through metals or heavy elements. An analysis of three-dimensional neutron tomography data to obtain the size distribution, some morphological characteristics, and the orientation of internal pores in cast iron fragments can provide not only qualitative, but also quantitative markers of the structure of cast iron products. We suggest that the versatility of gas-shrinkage porosity processes in the processing of cast iron in ancient workshops can serve as structural markers for identifying the location of iron producers, the presence of additional forging of cast iron products, as well as the features and primary composition of casting molds.
The production of activated carbon (AC) from lignocellulosic biomass through chemical activation is gaining global attention due to its scalability, economic viability, and environmental ad-vantages. Chemical activation offers several benefits, including energy efficiency, reduced car-bonization time, and lower temperature requirements. In this study, potassium hydroxide (KOH) was employed for chemical activation, resulting in activated carbon with a high specific surface area of ~3050 m²/g. The structural analysis revealed the presence of over 15% of few-layered graphene in the activated carbon matrix. X-ray diffraction (XRD) technique was employed to in-vestigate the activated carbon derived from rice husk (RH). The potential applications of activated carbon obtained from rice husks through chemical activation were explored, including its use for heavy metal removal, elimination of organic pollutants, and as an active material in hybrid energy storage devices. Furthermore, a scaling methodology for the production of activated carbon was proposed, facilitating its industrial implementation.
Among interactions of gamma ray with matter, Compton effect plays the leading role in the case when the energy of gamma ray exceeds a few hundred keV. At the same time, unless conventional gamma cameras that are used in CT scans, Compton cameras do not need collimators, that provides higher registration efficiency at several times. However, Compton cameras are not yet used for medical purposes because of its low spatial resolution. Recent advances in construction of new generations of detectors allowed the development of Compton cameras with improved spatial resolution. This has an important role for building CT scans used for registering isotopes that emit high-energy gamma radiation, and therefore allows expanding of the list of radiopharmaceuticals used in medicine. In this work, based on hybrid detector Timepix3, Compton camera was developed, along with algorithms to reconstruct and enhance image quality, allowing exceeding spatial resolution of 5mm.
Nowadays there is a huge demand of current sources for portable electronics. Sodium ion batteries seem to be a real alternative to Li-ion batteries. Therefore, energy materials for Na-ion current sources are now in need to be widely and carefully investigated. P2-layered oxide cathodes are cheap and have desirable Na-ion diffusion channels. Moreover, their structural stability is relatively high.
Ball milling treatment is inevitably employed to break down the large particles to realize the gravimetric specific capacity closer to the theoretical calculation [1-3]. It also can be used to solve the sluggish kinetics of Na+ diffusion. A decrease in particle sizes leads to shortening of the diffusion paths.
In this work we investigated how ball milling treatment would affect electrochemical properties of P2-Na0.7MnO2 cathode material. Grinding of the NMO powder itself (p-milled) and the cathode mixture (s-milled) was carried out. The results showed that grinding of the cathode slurry provides significantly more efficient particle size reduction as well as homogenization. During electrochemical tests at cycling rate of 0.1C both p-milled and s-milled electrodes revealed capacities of 180 and 193 mAh/g, respectively, which are greater than the theoretical one, 170 mAh/g. At high cycling speeds, the s-milled sample showed more stable operation than p-milled one.
REFERENCES
1. Kan, W. H.; Chen, D.; Papp, J. K.; Shukla, A. K.; Huq, A.; Brown, C. M.; McCloskey, B. D.; Chen, G. Unravelling Solid-State Redox Chemistry in Li Nb Mn O Single-Crystal Cathode Material. Chem. Mater. 2018, 30, 1655−1666.
2. Chen, D.; Kan, W. H.; Chen, G. Understanding Performance Degradation in Cation Disordered Rock-Salt Oxide Cathodes. Adv. Energy Mater. 2019, 9 (31), 1901255
3. Huang, B.; Wang, R.; Gong, Y.; He, B.; Wang, H. Enhanced Cycling Stability of Cation Disordered Rock-Salt Li1.2Ti0.4Mn0.4O2 Material by Surface Modification With Al2O3. Front. Chem. 2019, 7, 107
We present an early-stage prototype of positron emission tomograph (PET) based on 3x3x20 mm GAGG(Ce) scintillators optically coupled to 3x3 mm SiPMs (Onsemi fc30035-smt). The detectors are read by a Weeroc 32-channel Petiroc2A chip, allowing for precise charge and time measurements and designed specifically for SiPMs readout.
In the report, the energy and time resolutions of the system measured with Ti-44 source are presented, the imaging capabilities of the system are discussed.
The NA65 (DsTau) experiment uses a direct way to study the tau neutrino production from Ds decay, produced in high-energy proton-nuclear interactions. For registering such short lived particles, nuclear emulsion tracking detectors are used, capable of distinguishing events, despite of a high density of $10^5-10^6$ particles/cm$^2$.
The present report shows the first results of the pilot run analysis, especially the reconstruction of the primary proton interactions in the detector.
The main objective of the Baikal-GVD neutrino telescope is to detect high-energy neutrinos from astrophysical sources, thus contributing to the advancement of modern understanding of the high-energy universe. In the present work, we estimate the total neutrino detection rate from several possible particle sources, including TXS 0506+056, NGC 1068, and the Galactic Center, assuming a hadronic emission scenario. The neutrino rate is calculated using a pre-computed detector effective area for reconstructed track-like events. The daily source movement across the sky and the detector's registration efficiency as a function of energy and zenith angle are taken into account. The attenuation of the neutrino flux in the Earth is modeled using the $\nu$FATE package and is also incorporated into the neutrino detection rate calculations. We conclude that with a single Baikal-GVD cluster, the typical expected neutrino registration rate from the brightest sources is of the order of 0.05 events per year. With the full configuration of Baikal-GVD, consisting of 14 clusters, the event rate may reach the level of 1 event per year, potentially allowing for a significant detection over a time scale of several years.
The NOvA experiment, aimed at studying the neutrino oscillations in the muon neutrino beam, uses two segmented liquid scintillation detectors, with masses of 300 tons and 14 kilotons, respectively.
The large size and high segmentation of the NOvA detectors, as well as a flexible system of software triggers and data acquisition, make it possible to solve additional physical problems, in particular, to detect and study the atmospheric neutrino flux in NOvA detectors.
This report presents the technique for detecting and simulating events from interactions of the atmospheric neutrinos in the far detector of the NOvA experiment.
DUNE is a long-baseline experiment for neutrino oscillation studies. Its near detector complex consists of three main parts. One of them is ND-LAr, the liquid argon time projection chamber (LAr-TPC). In this type of detectors, a light collecting system (LCS) is commonly used as a trigger system. In this work the ND-LAr LCS is considered. It consists of two different types of photodetectors: LCM and ArCLight. The data from ProtoDUNE Dual Phase and Module 0 LAr-TPC prototypes was used to obtain the correct parameters of scintillation in liquid argon for Geant4 simulation. Then, the response of the Module 0 LCS in events with cosmic muons was compared with the response of its Geant4 model in identical simulated events to estimate the photon detection efficiency of LCM and ArCLight modules. After that, two-particle events with different shifts in time and space between tracks were simulated to determine the time and spatial resolution of the ND-LAr LCS. The capabilities of LCM and ArCLight technologies are compared. Obtained results allow us to judge whether the characteristics of the ND-LAr LCS satisfy the experiment requirements.
Modern astronomy aims to study the astrophysical objects with the various types of signals such as photons, neutrinos, cosmic rays and gravitational waves. To achieve the goals of the multi-messenger astronomy, experiments should exchange their data, which can be done with the alert messages.
Alert contains essential information about the detected event: sky coordinates, date, time of the detection, number of false events per year, energy, etc. The alert messages are distributed via
dedicated international networks, such as the Global Coordinates Network
(GCN), facilitating the rapid follow up of transient astrophysical
phenomena
The Baikal-GVD alert system receives external alerts automatically and applies different methods to search for signal coincidences. For better understanding of the Baikal-GVD alert system workflow and researching of the astrophysical neutrino sources the alert visualization is necessary.
This work deals with the approaches that are used within the coincidence search process and the visualization of the alerts: Baikal-GVD alerts and external messages from other experiments like the IceCube neutrino telescope, Fermi gamma-ray telescope and LIGO/VIRGO/KAGRA gravitational observatories.
This study investigates effects of lepton flavor violation (LFV) in proton-proton collisions at $\sqrt{s}=13$ TeV with $e\mu$ and $\mu\tau$ final states. Using an effective Lagrangian which characterizes the 4-fermionic contact interaction, a Monte Carlo simulation of the process was performed. As a result, two-dimensional distributions by the invariant mass $m_{inv}$ and azimuth angle $\varphi$ were obtained and on their basis, achievable restrictions on the SM parameters were established.
The consumption of wild and farmed mussels collected from the coastal water areas with different levels of anthropogenic pressure could lead to harm for human health. The safety of mussels as food could be assessed according to level of heavy metals and other toxic microelements in the soft tissues. In the study the risks of mussel consumption for local populations were assessed by using three approaches: comparison with the existing maximum permissible levels of elements in seafood, calculation of target hazard quotients based on the reference dose established by US EPA, and determination of maximum provisional tolerable consumption rate based on provisional tolerable weekly intakes established by FAO/WHO.
The mass fractions of 20 micro and macroelements in soft tissues of mussels from 3 stations of different anthropogenic pressure in 2013-2019 period were determined by using neutron activation analysis.
According to the study the risks for human health demonstrated such elements as Co, Zn, As, Se and I. The levels of maximum consumption rate for such elements as Al, As and I should be less than 500 g/week per person. The obtained temporary fluctuations in mass fractions of considered elements help to reveal increasing the risks in several times depending on seasonal and annual natural and anthropogenic changes of features of the surrounding waters. It was concluded that the increasing of risks in winter seasons of storms due to high levels of elements in suspended matter.
Neutrophils release decondensed chromatin or extracellular traps (NETs) in response to various physiological and pharmacological stimuli. Apart from host defensive functions, NETs play an essential role in the pathogenesis of various autoimmune, inflammatory, and malignant diseases. In recent years, studies have been performed on photo-induced NET formation, mainly activated by UV radiation. Understanding the mechanisms of NET release under the influence of UV and visible light is important to control the consequences of the damaging effects of electromagnetic radiation. Raman spectroscopy was applied to record characteristic Raman frequencies of various reactive oxygen species (ROS) and low-frequency lattice vibrational modes for citrulline. NETosis was induced by irradiation with wavelength-switchable LED sources. Fluorescence microscopy was used to visualize and quantify NET release. The ability of five wavelengths of radiation, from UV-A to red light, to induce NETosis was investigated at three different energy doses. We demonstrated, for the first time, that NET formation is activated not only by UV-A but also by three spectra of visible light: blue, green, and orange, in a dose-dependent manner. Using inhibitory analysis, we established that light-induced NETosis proceeds through NADPH oxidase and PAD4. The development of new drugs designed to suppress NETosis, especially when induced by exposure to intense UV and visible light, can help to mitigate light-induced photoaging and other damaging effects of electromagnetic radiation.
Transglutaminase 2 (TG2) is a pivotal enzyme involved in various biological processes such as wound healing, apoptosis, and cell differentiation. Depending on the environmental conditions, TG2 can adopt two distinct conformations: the open and closed states. Notably, the open conformation of TG2 has been associated with the pathogenesis of several diseases, including celiac disease and certain cancers. Recent investigations have demonstrated that within human cells, open-state TG2 can exist both as monomers and dimers. The monomeric form primarily exhibits transamidation activity, whereas the dimeric form is postulated to exert cytotoxic effects.
While several structures of the monomeric open-state TG2 are available in the Protein Data Bank, structures representing the dimeric form remain elusive. The objective of this study is to elucidate the structural distinctions between TG2 monomers and dimers using small-angle X-ray scattering (SAXS).
This study was supported by Ministry of Science and Higher Education of the Russian Federation, project FSMF-2022-0007 “Development of technology for rational and highly productive use of agro- and bioresources, their efficient processing and obtaining safe and high-quality sources of food and non-food products”.
The boron neutron capture therapy technique has been appealing to advance the technical and medical development of aspects of malignant tumors. The concept of the method has been aimed at dose contribution by secondary particles for targeted tumor sites while neutron beams do not have enough radiation effects to damage healthy cells with an advantage. This study focused on calculating the dose deposition of secondary particles from nuclear reactions between various mono-energetic neutrons and 10B with different concentrations. In this simulation, we carried out the single-cell model of human glial tumors with several potential distributions of boron nanoparticles. The resulting absorbed boron dose was more significant than the dose from other particles on the lower part of epithermal neutron energy ranges when higher boron concentration. Accordingly, we estimated the DNA damage in the cell geometry with the sphere and ellipsoid caused by the secondary particles using the GEANT4-DNA toolkit, respectively. The findings highlight the importance of precise dose calculations of high LET particles and considering secondary particle effects when evaluating the efficacy of BNCT in tumor treatment.
Keywords: BNCT, mono-energetic neutron, GEANT4-DNA, nuclear reaction
The patterns of induction and repair of clustered DNA double-strand breaks (DSBs) (DSBs) in normal human skin fibroblasts under the action of γ-rays 60Co, protons, accelerated ions 11B, 20Ne, 15N and 12C were investigated. Using immunocytochemical staining method, radiation-induced γH2AX/53BP1 foci were analyzed in detail in 3D images.
It was found that the action of accelerated heavy ions with low and intermediate energies produces complex clusters including up to six or more individual γH2AX/53BP1 foci, in contrast to the action of γ-rays. The largest and most complex foci clusters are formed by the action of 20Ne ions.
The repair kinetics of radiation-induced γH2AX/53BP1 foci in cells under the action of heavy ions proceeds significantly slower than under γ-irradiation. It was shown that with decreasing energy of accelerated particles and increasing of LET, the efficiency of clustered DNA DSBs repair decreases.
The key damage to the cell that determines its fate is double-strand breaks (DSB) of DNA, the incorrect repair of which leads to chromosomal aberrations that can be fatal for the cell [1]. Therefore, understanding the mechanisms of induction and kinetics of DSBs DNA repair is important for predicting the radiation-induced response to radiation therapy and the survival of cells that have been exposed to ionizing radiation.
This work is devoted to mathematical modeling of the process of DSBs repair after exposure to rare ionizing radiation with different characteristics. Mathematical modeling of several stages of the cellular response to irradiation of Chinese hamster V79 cells with X-ray radiation and human carcinoma cells with gamma radiation, such as induction and repair of DSBs DNA, kinetics of formation of improperly prepared double-stranded DNA breaks and formation of chromosomal aberrations, was carried out [2].
A comparative analysis of model data with experimental data obtained by the method of premature chromosome condensation showed that for X-rays and for gamma rays, the kinetics of DSBs repair is the same in mammalian and human cells and obeys the same law. The number of DSBs and chromosomal aberrations is directly proportional to the radiation dose and the phase of the cell cycle.
We consider a model of the superconducting quantum interference device (SQUID) with a single $\phi_0$ junction based on the Landau-Lifshitz-Gilbert equations for the magnetization of the ferromagnetic layer and resistively shunted junction model for phase difference of $\phi_0$ Josephson junction. Within this model, a phenomenon of magnetization reversal is studied in a wide range of parameters using the MPI-based parallel implementation of the numerical simulation procedure. It was revealed that the intervals of the magnetization reversal have a periodic structure which depends on the amplitude of the external magnetic field pulse and on the inductance of the SQUID. One expects that the results are of interest within applications in design and optimization of modern superconducting electronics and spintronics.
A project of the OLVE-HERO space detector for measurement of the cosmic rays in the range 1012–1016 eV is proposed. It will include a large ionization-neutron 3D calorimeter with a high granularity and geometric factor of ∼16 m2 sr. The main OLVE-HERO detector is expected to be an image calorimeter with boron loaded plastic scintillator and a tungsten absorber. Such a calorimeter can measure an additional neutron signal that should improve the detector energy resolution and also the rejection power between electromagnetic and nuclear components of cosmic rays. The Monte-Carlo results of a simplified version of the detector from cosmic protons flux are presented. The purpose of this work is to study the background level that occurs during the formation of evaporation neutrons in the detector, their slowing down to thermal energies, followed by capture by B-10 nuclei and the production of ɑ-particles with an energy of ~2 MeV.
Calculating multidimensional integrals with a singularity of type 1/(x-c) is not a simple task. The methods used to calculate such an integral must effectively bypass the singularity, minimizing the error. This work presents an algorithm that, in the process of calculating the integral, analyzes the area of integration, dividing it into subsegments. Subsegments containing a singularity, as well as those located close to the singularity, are excluded during the final calculation of the integral. Integrals final calulation is carried out using the Monte Carlo integration method. The algorithm allows to calculate both one-dimensional and multidimensional integrals.
The formation of weakly bound clusters and hypernuclei in the hot and dense environment at midrapidity is one of the surprising phenomena observed experimentally in heavy-ion collisions from low SIS to ultra-relativistic LHC energies. This is also known as the `ice in a fire' puzzle. Three approaches have been advanced to describe the formation of clusters: cluster formation during the entire heavy-ion collision by potential interactions between nucleons ('potential mechanism') and deuteron production by catalytic hadronic reactions ('kinetic mechanism') as well as by coalescence at kinetic freeze-out.
We present here results from PHQMD, a novel microscopic n-body transport model based on the QMD propagation of the baryonic degrees of freedom with density dependent 2-body potential interactions. The clusters, formed via 'potential' mechanism, are recognized by the Minimum Spanning Tree (MST) algorithm which is identifying bound clusters by correlations of baryons in coordinate space.
The PHQMD approach allows for studying in the same framework the two above mentioned mechanisms, to investigate how and when clusters are formed and finally for comparing the results with present data from GSI to RHIC energies.
Computed tomography using X-rays, neutrons, and electromagnetic fields is becoming more popular in fields like medicine, materials science, geology, and archeology. Modern materials science holds a special place for neutron tomography [1]. This method has advantages like deep penetration, sensitivity to light elements, and clear contrast for elements with similar atomic numbers because of how neutrons interact with matter.
Neutron tomography has unresolved problems such as lengthy experiments, weak image quality, and high computational resource usage. Developing neutron tomography requires new math algorithms for data processing and reconstruction. The most promising in this field are algorithms based on convolutional neural networks and deep learning [2].
In this work, the most optimal architecture of a convolutional neutron network for preprocessing and tomographic reconstruction of neutron radiographic data was implemented. The neural network was trained using a set of data obtained at neutron tomography stations at the Frank Laboratory of Neutron Physics and the National Research Center “Kurchatov Institute”. The result was a program whose efficiency was compared with existing data processing methods.
This work was carried out with the financial support of the AYSS grant No. 23-402-02.
1. Podurets K. M. et al. Modern methods of neutron radiography and tomography in studies of the internal structure of objects //Crystallography Reports. – 2021. – Т. 66. – С. 254-266.
2. Micieli D. et al. Accelerating neutron tomography experiments through artificial neural network based reconstruction //Scientific Reports. – 2019. – Т. 9. – №. 1. – С. 2450.
The work is devoted to the creation of computational tools for designing a UCN source for a pulsed reactor. Its result is two software products that can be used in the course of further work. One of them is designed to calculate the transport properties of UCN neutron guides based on given geometric dimensions, material, and surface roughness parameters. The second program is designed to calculate the dynamics of UCN motion in magnetic fields of magnetic resonance devices. This provides designers with the necessary tool for optimizing the parameters of the designed devices designed to form the pulsed structure of the neutron flux and slow down very cold neutrons to energies typical for UCN.
Optical materials based on cesium lead halide perovskite nanocrystals are promising due to their unique optical, optoelectronic and photoelectric properties. The convenience of using perovskite nanocrystals in applications such as LEDs, solar cells, etc. lies in their ability to smoothly adjust the position of luminescence depending on the ratio of halogen ions, obtaining mixed nanocrystals. The glass ceramics obtained in this work, in particular, can be used as a luminescent material, laser media, and scintillators for X-ray imaging.
However, one of the difficulties when working with materials containing perovskite nanocrystals is that they have several phase transformation points at relatively low temperatures (30 – 330 °C), which affects their optical properties, so the study of temperature effect on these new materials is extremely important.
In this work, borogermanate glass ceramics with mixed CsPb(BrxI1-x)3 perovskite nanocrystals were synthesized and studied. A study of their spectral and luminescent properties showed that an increase in the concentration of iodine in the composition of glass ceramics leads to an increase in the band gap of nanocrystals and a shift of their luminescence and absorption spectra to longer wavelengths. It was also shown that equimolar replacement of bromine with iodine in the composition of mixed nanocrystals increases the luminescence quantum yield of glass ceramics by up to 35%. Temperature measurements show that hysteresis is observed in the dependence of optical density on temperature in the heating-cooling cycle, and these measurements also made it possible to construct the dependence of the melting and crystallization temperatures of nanocrystals jbtained in the glass matrix on the ratio of bromine and iodine in the composition of the nanocrystals.
This work was funded by Russian Science Foundation (№ 19-72-10036).
Abstract: Zinc oxide (ZnO) has been widely studied over the last decade for its remarkable properties in optoelectronic and photovoltaic devices because of its high electron mobility and excitonic
properties. It has probably the broadest range of nanostructured forms that are also easy and cheap
to synthesize using a wide variety of methods. The volume of recent work on ZnO nanostructures
and their devices can potentially overshadow significant developments in the field. Therefore, there
is a need for a concise description of the most recent advances in the field. In this review, we focus on
the effect of ZnO nanostructure morphologies on the performance of ZnO-based solar cells sensitized
using methylammonium lead iodide perovskite. We present an exhaustive discussion of the synthesis
routes for different morphologies of the ZnO nanostructure, ways of controlling the morphology, and
the impact of morphology on the photoconversion efficiency of a given perovskite solar cell (PSC).
We find that although the ZnO nanostructures are empirically similar, one-dimensional structures
appear to offer the most promise to increasing photoconversion efficiency (PCE) by their proclivity to
align and form vertically stacked layers. This is thought to favor electron hopping, charge mobility,
and conductivity by allowing multiple charge conduction pathways and increasing the effective
junction cross-sectional area. The combined effect is a net increase in PCE due to the reduced surface
reflection, and improved light absorption.
Industrial Detector of REactor Antineutrinos for Monitoring (iDREAM) is a prototype detector designed to demonstrate the feasibility of antineutrino detectors for remote reactor monitoring and safeguard purposes. The 1 ton Gd-doped liquid scintillator detector is mounted in the Kalinin nuclear power plant (Russia), 20 m from the 3 GWth VVER type commercial reactor. Antineutrinos are detected via inverse beta decay on protons. The detector took data both in reactor ON and OFF modes. In this talk the iDREAM measurements of the accidental and correlated backgrounds will be discussed. The iDREAM antineutrino data and the detector prospects will be reviewed in the framework of applied antineutrino physics.
The growing demand for consumer electronics and electric vehicles has led to a substantial increase in the consumption of lithium-ion batteries (LIBs). The lack of economically viable and environmentally friendly recycling processes for LIBs could lead to an environmental crisis and resources shortage. Amongst other techniques, liquid-liquid extraction and solid-liquid extraction are the two most known concepts applied for separation and extraction of metals from aqueous solutions. Compared to the two, the former has wide applicability in hydrometallurgical processes and can handle large volume of aqueous solutions but involves high volume of organic solvents1. As a promising alternative, solid-liquid process using nanofiber adsorbents shows great potential for extracting valuable metals due to their unique properties, such as high specific surface area2. This study focused on synthesizing a novel nano-adsorbent material, polyethylene terephthalate (PET)-Di-2-ethylhexyl phosphoric acid (DEHPA). The optimal volume ratio of PET (10 wt%) and DEHPA for complete functionalization was found to be 9:1. While the electrospinning process parameters were determined to be 15 cm, 30 kV, and 1.0 mL/h. The characterization of PET and PET-DEHPA nanofibers was carried out by FTIR, XRD, TGA, SEM, and BET. The FTIR spectra of PET-DEHPA nanofibers revealed the presence of the P-O-C functional group at 1011 cm-1, while SEM micrographs displayed crosslinked nanofibers. Additionally, the TGA profiles showed that a single-step degradation at 353 °C for pristine PET nanofibers while the thermogram of PET-DEHPA nanofibers exhibited a two-step degradation at 240 – 327 °C and 327 – 570 °C. Therefore, the results confirmed the successful functionalization of PET polymer nanofibers which are intended for use as adsorbents for valuable metals from spent lithium-ion batteries.
[1] Roy P, Orecchioni M, Ley K. How the immune system shapes atherosclerosis: roles of innate and adaptive immunity. Nature Reviews Immunology. 2022 Apr;22(4):251-65.
[2] Laatikainen K, Pereao O, Bode-Aluko C, Ndayambaje G, Petrik L. Metal Specific Functionalized Nanofibers. Multidisciplinary Digital Publishing Institute Proceedings. 2019;29(1):1.
BM@N (Baryonic Matter at Nuclotron) is the first experiment operating taking data at the accelerator complex of NICA-Nuclotron. The BM@N physics program is based on studies of highly compressed nuclear matter in heavy ion beams. The Nuclotron provides heavy ion beams with energies from 2.3 to 4.5 AGeV, which is suitable for studies of strange mesons and multi–strange hyperons produced in nucleus-nucleus collisions close to the kinematic threshold.
The first experimental run in 2017 used a carbon beam at 4 and 4.5 AGeV kinetic energy and a set of nuclear fixed targets: Al, C, Cu, Pb. This contribution describes a methodology to measure the production cross section and yields in the Λ→p+π- decay channel. The results are compared with theoretical models and experimental C + C data at a beam energy of 2 AGeV (HADES, GSI).
Baryonic Matter at Nuclotron (BM@N) is the fixed target experiment at the NICA accelerator complex. Detectors based on Gas Electron Multipliers (GEM) are used at the central tracking system, which is located inside the BM@N analyzing magnet. Central tracking system consists 14 GEM-detectors, with two different sizes of active area (163×45 cm2 and 163×39 cm2), combined in the 7 detector planes. This talk is presents the results of system perfomance at first BM@N physics run at this winter, current status and future plans of our team.
In the relativistic heavy ion collisions at the beam energy of a few GeV the strongly interacting matter is created at high baryon densities and relatively low temperatures. Azimuthal anisotropy of the produced particles provides a valuable insight into the properties of this form of matter. In this work we discuss the layout of the upgraded Baryonic Matter at Nuclotron (BM@N) experiment and the anticipated performance for measuring the directed and elliptic flow of protons relative to spectator symmetry plane. We present the results of the study on the scaling properties of anisotropic flow of protons at the beam energies
of several GeV.
One of the non-trivial problems in high energy hadronic interactions is the treatment of the process of the production of the final state hadrons from quarks, antiquarks and gluons of the parton shower. Many models of hadronization were developed and tuned to electron-positron collider data. However, data from recent both collider and cosmic ray experiments in high energy physics show the deviation from model predictions in proton-proton and meson-nucleus collisions, that seems to be not connected with collective effects. This motivates the search for new mechanisms taking place during hadronization process.
String fragmentation models of hadronization proved to provide the best self-consistent description of hadronization. One of the two most widely used approaches is LUND fragmentation scheme, that is historically implemented in well-known PYTHIA Monte-Carlo generator. The other is based on the Area Law and was first developed for use in Caltech-II model. This approach uses the Nambu-Goto action to derive the equations of relativistic string dynamics. This approach has a potential for future modifications but in existing models it is used in greatly constrained form.
The Generalized Relativistic String Model (GRSM-SI) is proposed to implement the full potential of the mathematical apparatus developed for Nambu-Goto strings. In the Model, the initially-stretched relativistic strings are considered. The realistic initial conditions are used that define the unique gauge that was not previously used in models. The Model provides the framework to calculate all essential string properties including spin-orbital angular momentum. The new fragmentation mechanism is introduced that allows the arbitrary daughter strings to be considered. The all-in-all freedom of the Model opens the possibilities of implementation of new mechanisms of particle production.
A custom Application Specific Integrated Circuit (ASIC) TIGER (Turin Integrated Gem Electronics for Readout) is capable of simultaneous precise measurements of both the charge and time characteristics of signals in gaseous detectors. Flexibility of TIGER operation parameters makes it attractive to be evaluated as a front-end electronics solution for Straw-based Trackers of future High Energy and Neutrino Physics experiments. We present first performance measurements done with Straw drift tubes operated with the TIGER-based readout. The results obtained with the SPS muon beam at CERN allows us to explore the advantages and limitations of the TIGER readout option for Straw tubes. An overview of possible further development is presented.
It is known, that about 8% of the total land area is irrigated by wastewater, and vegetables are among the main crops produced via wastewater irrigation throughout the world. Generally, industrial wastewaters are contaminated with an appreciable amount of trace and toxic elements, that can be accumulated in agricultural soils and crops and then transferred to the human body via the food chain leading to diseases. Therefore, this laboratory study evaluated the accumulation and translocation of Cr and Ni in the edible parts and roots of lettuce (Lactuca sativa) and green onion (Allium fistulosum L.) irrigated with industrial effluents and assessed their potential health risks via oral consumption.
The content of Cr (7.36–7.58 mg/kg dry weight) and Ni (7.28–10.85 mg/kg dry weight) determined in the edible parts of leafy vegetables varied within a narrow range. The values of bioaccumulation factor of Ni in lettuce decreased with increasing of metal concentrations in the industrial effluents. Conversely, the bioaccumulation factors of Cr for both leafy vegetables and Ni (for onion) were higher when irrigated with wastewater. The levels of Cr in the parts of lettuce and Ni in both vegetables and soil followed the order: soil ≥ roots > edible part. The different order of Cr translocation was observed for onion: roots ≥ soil > edible part. The obtained values of estimated daily intake of Ni via consumption the leafy vegetables were by two orders of magnitude lower than the safe daily dietary intake established for Ni (20 µg/kg bw day) and similar to those reported for Cr (0.71-2.9 µg/kg bw day).
A study of ketoprofen was carried out using experimental as well as computational methods. Ketoprofen is a representative of the group of non-steroidal anti-inflammatory drugs widely used in modern medical therapy. It has a high analgesic, anti-inflammatory and antipyretic activity. Reactivity of ketoprofen is closely connected with its structures features. Ketoprofen sample was investigated by the following experimental methods: differential scanning calorimetry, IR-spectroscopy and Raman-spectroscopy. The structure of ketoprofen was also investigated by DFT (BP86/def2-SVP) method. A comparative analysis of the calculated and experimental data was performed. Investigation of ketoprofen sample by IR spectroscopy demonstrated concordance of spectra obtained in KBr tablet and by FTIR method. The most intensive peaks in these spectra correspond to the v(C-O) and two v(C=O) vibrations. A good agreement between the experimental and calculated in the DFT approximation vibrational frequencies of ketoprofen was obtained.
The main purpose of this study is to investigate the physicochemical properties of a pharmaceutical substance called ibuprofen. The research of medicines is crucial for the promotion and improvement of the healthcare system. The first aim of the study is to check the purity of the ibuprofen sample obtained in the pharmacy and its analysis in comparison with the information provided in the relevant literature. Various research methods are used to test ibuprofen. The following experimental methods were used: differential scanning calorimetry (DSC), X-ray powder diffractometry (XPRD), IR, NMR and RAMAN spectroscopy. The work presents a preliminary description of these methods, as well as the experimental results obtained for the tested ibuprofen sample. The NMR spectroscopy method revealed that the sample contains pure ibuprofen and can be used for further investigations. The powder X-ray diffraction method showed that the studied ibuprofen sample was in a crystalline form. The oscillation frequencies obtained from experimental measurements closely corresponded to the values calculated using the density functional theory (DFT) approximation, demonstrating a high degree of agreement. Linear correlations were found between the experimental oscillation frequencies and the frequencies calculated by DFT method.
Methods of X-ray diffraction analysis (XRD) have allowed us to determine the structure of many materials and substances around us. The configurations of crystal lattices of a variety of inorganic materials became known to science, which made it possible to create new compounds with specified properties and characteristics. Advances in the decoding of solid materials and crystals were attempted to be transferred to the field of biological substances. However, molecular compounds turned out to be more difficult to study XRD. Molecules practically do not lend themselves to high-quality crystallization, which does not allow the use of X-ray radiation for 40% of biological structures: proteins, macromolecules, and so on [1-2]. Nevertheless, alternative methods of research, for example, methods from the field of chemistry, do not allow us to decipher the structure of a molecule at the atomic level. That is why ultrashort laser pulses have now been used as a source of XRD in studies with molecular samples [3-5]. This made it possible to get rid of existing obstacles in research. For the use of ultrashort laser pulses, there is no need for crystallization of the sample, in addition, the pulse has time to fix the structure before its possible change (rearrangement of atoms, change of bonds), since it works on the same time scale as the molecule. To date, the world's leading laboratories are already using ultrashort laser pulses in working with biological substances[6-8]. But there are problems with decrypting the received data. In this paper, a new approach is proposed to describe the spectrum of interaction of a pulse with a complex polyatomic molecular structure.
Molecular structures are complex compounds that are difficult to analyze. The randomness of the arrangement of atoms in them makes it difficult to decipher the obtained spectra in XRD methods, since they are mainly aimed at working with inorganic substances whose crystal lattice is ordered. Complex biological structures such as proteins, amino acids, macromolecules, DNA and RNA do not have obvious symmetry and periodicity. However, most macromolecules are a set of repeating units formed from smaller molecules, which makes it possible to calculate the spectrum in an analytical form. In this paper, we propose a method for calculating the spectrum for a DNA molecule in an analytical form by finding symmetries in a macromolecule. Let's consider the calculation using the example of a DNA macromolecule. The nitrogenous bases repeated in it allow them to be put into separate groups for calculation – symmetry. When calculating a long chain of sequences, such groups are summed up, which simplifies the mathematical description of the interaction spectrum. For example, there is a piece of the DNA chain of the bacterium Escherichia coli str. K-12 substr. MG1655 of six nitrogenous bases: thymine, guanine, thymine, thymine, guanine, thymine (TGTTGT). Repeating nitrogenous bases according to the principle of complementarity create identical pairs: thymine-adenine, guanine -cytosine. These pairs can be combined in symmetry, thereby simplifying the calculation in an analytical form.
1 Zygmunt S. Derewenda & Adam Godzik. The “Sticky Patch” Model of Crystallization and Modification of Proteins for Enhanced Crystallizability. Methods in Molecular Biology. – Vol 1607, 2017.
2 BERNAL, J., CROWFOOT, D. X-Ray Photographs of Crystalline Pepsin. Nature 133, 794–795 (1934).
3 J. Deisenhofer, O. Epp, K. Miki et al. X-ray structure analysis of a membrane protein complex. electron density map at 3 a resolution and a model of the chromophores of the photosynthetic reaction center from rhodopseudomonas viridis // Journal of Molecular Biology. — 1984. — Vol 180. — Pp. 385–398.
4 Suryanarayana, C. & Grant, N. M. X-Ray Diffraction: A Practical Approach (Plenum Press, 1998).
5 Jones, N. Crystallography: Atomic secrets. Nature 505, 602–603 (2014).
6 Schoenlein, R. et al. Recent advances in ultrafast X-ray sources. Philos. Trans. R. Soc. A 377, 20180384 (2019).
7 Duris, J. Tunable isolated attosecond x-ray pulses with gigawatt peak power from a free-electron laser / J. Duris, S. Li et al. // Nature Photonics. —2020. — Vol. 14. — Pp. 30–36.
8 Maroju, P. K. Attosecond pulse shaping using a seeded free-electron laser / P. K. Maroju et al. // Nature. — 2020. — Vol. 578. — Pp. 386–391.
The NTsim is a framework, which aims is to simulate data for neutrino experiments, such as IceCube, KM3NET/Arca, Baikal-GVD, P-ONE and others planned in future, with the initial focus on the Baikal-GVD telescope. The main goal of the project is to reach the desired time of simulation, not compromising the accuracy of simulation. To achieve this, different methods are used in the framework. The one described in this talk is optimization of cascade simulation process using a spatial parametrization. Different options for this kind of optimization have been investigated during the work and the most suitable one is developed and implemented into the simulation chain. To validate this specific method, the distributions of parameters have been illustrated and compared to the original detailed simulation, the results of the comparison will be presented in the talk.
The solar wind is a key link in the Sun-Earth system, but neither the physics of its formation nor the physics of its evolution are yet completely clear. This fact was the main reason for the launch in 2018 of a special satellite mission, Parker Solar Probe (PSP), largely focused on the issue of solar wind research. Over the first five years of operation, this mission provided specialists with a huge influx of new data with high temporal resolution and large variations in heliocentric distances. In particular, it made it possible to study in detail the spectra of fluctuations of solar wind fields: the velocity field and the magnetic field, and to take a new look at the turbulent cascade formed in interplanetary plasma.
PSP data confirmed the previously discovered presence in the picture of the spectral density of magnetic field energy fluctuations of two breaks, the first of which is located near the subionic scale, the other at the left end of the inertial interval, that is, in the region of large-scale vortices. There is no consensus on the evolution of these markers yet, so at the moment, studying the dynamics of these kinks, which limit the inertial interval and determine the turbulent cascade, is key. And if to describe a near-dissipative fracture it seems necessary to use a kinetic approach, then the evolution of a large-scale fracture can apparently be described while remaining within the framework of the magnetohydrodynamic paradigm. In this paper, using PSP mission data as a basis, we describe the free evolution of a turbulent cascade using a shell isotropic MHD model and try to reproduce the actually observed evolution of the spectral break.
To describe the turbulent cascade, we use the shell model, or, in other words, the cascade model developed by F. Plunian and P.G. Freak. The class of shell models for hydrodynamic type systems is the Fourier images of a system of MHD equations, in which the images of nonlinear terms are approximated by the sum of quadratic nonlinearities in such a way that in the non-dissipative case the three-dimensional MHD conservation laws are satisfied: conservation of total energy, magnetic and cross helicity. In this case, the continuous spectral scale is replaced by a set of discrete spectral shells, and the nonlinear terms take into account the exchange of energy only between neighboring shells. In this approach, we use PSP data near the Sun as input and study, in the process of free evolution of the turbulent cascade, the possible evolution of the spectra and the dynamics of the motion of a large-scale break. The obtained results of cascade modeling are compared with PSP data on the Sun-Earth axis and, based on the comparison, a conclusion is drawn about the applicability of shell analysis and the free degeneracy hypothesis.
The authors would like to express their sincere gratitude to P. G. Frick for helpful advice and the model provided, and to the Parker Solar Probe and CDAWEB team for providing satellite data. The work was supported by the BAZIS Foundation grant N 21-1-3-63-1.
The magnetic field in the inner heliosphere, including both regular and irregular components, was modelled. The regular component is described by Parker’s model, which assumes that the magnetic field is frozen inside the solar wind plasma. To include the irregular component of the field, a Gaussian random field was generated on the field source surface, and later transported into the inner heliosphere along the regular component field lines. An agreement between the model and the observed field by spacecrafts such as ACE, Ulysses, Voyager, and Parker Solar Probe is shown for different heliolatitudes and helioradiuses.
The dynamics of S-stars in the Galactic centre was studied using the physics-informed neural networks. The neural networks are considered for both, Keplerian and the General Relativity dynamics, the orbital parameters for stars S1, S2, S9, S13, S31, and S54 are obtained, and the regression problem is solved. It is shown that the neural network is able to detect the Schwarzschild precession for S2 star, while the regressed part also revealed an additional precession. Attributing the latter to a possible contribution of a modified gravity, we obtain a constraint for the weak-field modified General Relativity involving the cosmological constant. The analysis shows the efficiency of neural networks in revealing the S-star dynamics and the prospects upon the increase of the amount and the accuracy of the observational data.
Nowadays the most widely used catalysts for organic synthesis mainly made of noble and rare earth metals that significantly increases the cost of many products. Moreover, 80% of catalyst used in domestic industry including oil and chemical production are imported and it can cause problems in the present political situation.
Suggested alternative to the pricey catalysts is the transition metals borides [1], [2]. Along with the other transition metal borides, tungsten borides were studied as potential catalysts for hydrogen evolution reaction (HER) and CO2 conversion to CH4, then, their usage as the catalysts for organic synthesis was proposed.
Furthermore, as it was showed for Mo-B system [3], the catalytic activity of transition metal borides increases with the boron stoichiometric content. Hence, the higher tungsten boride (WB5-x) is the most promising one beyond the other tungsten borides.
Here we performed the comprehensive study of surfaces of WB5-x using density functional theory (DFT) as implemented in VASP package. We studied the surface energies of WB5-x slabs with (001), (010), (100), (110), (101), (111), (130), and (201) crystallographic orientations. Calculated surface energies were used to make Wulff construction by using Python WulffPack module to find the equilibrium morphology of higher tungsten boride single crystal. It was shown that boron terminated (010) and (001) surfaces and tungsten terminated (101) surface are the most stable.
As WB5-x has also proposed as the alternative to the catalysts for an automotive motor, the adsorption of the different atmosphere gases (СО, СO2, H2, N2, O2, NO, NO2, H2O, NH3, SO2) on its stable surfaces was investigated. It was shown that at the (010) surface the lowest adsorption energies have the NO, CO and H2 molecules. On the contrary, WB5-x surface doesn’t adsorb SO2 gas. On (101) surface О2, NH3 and NO2 have the lowest adsorption energies. It is worth noting, that O2 molecule easily dissociates o both of considered surfaces.
Obtained results allows us to possess higher tungsten boride as a perspective catalyst or co-catalyst for many different reactions including photocatalytical ones. Furthermore, the experimental work to prove data obtained is already started.
References:
[1] M. M. Dorri и др., «Synthesis and characterization of CrB2 thin films grown by DC magnetron sputtering», Scripta Materialia, V. 200, P. 113915, 2021, doi: 10.1016/j.scriptamat.2021.113915.
[2] W. Zhao и др., «Surface Modification towards Integral Bulk Catalysts of Transition Metal Borides for Hydrogen Evolution Reaction», Catalysts, V. 2, № 12, P. 222, 2022, doi: 10.3390/catal12020222.
[3] S. Gupta, M. K. Patel, A. Miotello, и N. Patel, «Metal Boride-Based Catalysts for Electrochemical Water-Splitting: A Review», Advanced Functional Materials, № 30, P. 1906481, 2020, doi: 10.1002/adfm.201906481.
Efficiency assessment of IRT-T research reactor cooling system by machine learning methods
Tomsk Polytechnic University, Tomsk, Russian Federation.
Machine learning is one of the components of artificial intelligence, the purpose of which is to build analytical models by learning from historical data [1]. The concept of artificial intelligence and machine learning can be traced back to the mid-20th century, when the inventor Alan Turing proposed creating a “machine that can learn from experience”. After decades of gradual development and technological innovation, machine learning has become a powerful format for a wide range of scientific research and industrial applications, with the special power to find patterns in complex large-dimensional data and study non-dimensional relationships [2].
In modern industrial practice machine learning methods are already used to simplify and optimize the processes on site. However, nuclear power plants and research reactors do not use data analysis for evaluation of technological or neutron-physical characteristics.
In this research, it is proposed to develop the software for evaluation of heat exchanger fouling. That allows to predict the service time so the personnel will not face any maintenance difficulties, and heat transfer efficiency could be in high value throughout the operational time.
Experimental data from IRT-T Research Reactor SCADA System Database was taken and introduced into the workspace through the transforming software that was already developed. Using supervised learning with regression the most important parameters for changing of heat transfer were obtained and the heat exchange deviations throughout the year were predicted and performed.
References
1. Machine Learning Model for Analyzing Learning Situations in Programming Learning / Sh. Kawaguchi, Y. Sato, H. Nakayama [et al.] // 2018 IEEE 3rd International Conference on Big Data Analysis, ICBDA 2018: 3, Shanghai, 09–12 March 2018. – Shanghai, 2018. – P. 74-79. – DOI 10.1109/ICBDAA.2018.8629776. – EDN CMGSAL.
2. Korobova, M. A. Overview of Machine Learning Methods Used in Algorithmic Trading / M. A. Korobova, D. I. Gubina // Languages in Professional Communication, 28 April 2022, 2022. – P. 54-59. – EDN GQKESU.
The problem of creating transplants to replace and stimulate the regeneration of damaged organs or tissues in medicine is of critical importance. In particular, there are various pathologies of the cornea of the eye (injuries, degenerative processes) that cause irreversible changes and lead to blindness. The mammalian corneal stroma can serve as a potential material for creating an artificial cornea. However, when creating such implants, problems of immunogenicity, biocompatibility and long-term preservation of optical transparency after implantation arise. Despite the large number of artificial corneas offered, the search for the optimal composition of the corneal implant and methods of its processing remains an urgent task.
It is known that the basis of the corneal stroma is type I collagen. One of the options for reducing the ability of collagen to hydrate is collagen crosslinking (the formation of cross-links between polypeptide chains). An early study of corneal grafts ("Corneoplast") showed that dehydrothermal crosslinking (DTС) of the corneal stroma can be used to increase the resistance of grafts to hydration without critical loss of optical and strength properties. In modern corneal surgery, materials with similar properties are not yet used.
The aim of this work was to assess the effect of DTC of stromal corneal grafts based on the material for keratoplasty Corneoplast at temperatures of 60, 100, 140℃ on their physical, structural and biological properties. The study of the graft structure was carried out by the method of small-angle X-ray scattering (SAXS), Raman spectroscopy (RS) was used to study the degree/level of hydration of the material.
As a result of the study, data were obtained on the structure and properties of the grafts under study, on the basis of which it can be concluded about the ability of grafts to hydrate/dehydrate and about the storage conditions of grafts for medical purposes. In particular, the ability of grafts to hydrate/dehydrate in water and in a phosphate-salt buffer (pH=7.4) and related changes in structural parameters such as the D-spacing, the distance between the triple helices of collagen, the distance between amino acid residues, the contributions of “free” and collagen-bound water in the grafts were evaluated. It was also found that small-angle X-ray scattering and Raman spectroscopy are reliable methods of quality control of materials for keratoplasty. According to our research, it is possible to make changes to the protocol to improve the quality of preparation of grafts for keratoplasty.
Ferritin is a typical protein cage structure which is formed from 24 polypeptide subunits by the process named self-assembly. An assembled globule of ferritin is shaped into a hollow sphere with the key function of iron storage [1]. Thus, ferritin is able to store up to 4500 iron atoms within its shell [2] in the form structurally similar to ferrihydrite (5Fe2O3·9H2O) [3]. Ferritin is commonly used in structural biology due to its stability in a wide range of conditions (in particular, thermal and different pH). This globular protein also has a plea of biophysical and biomedical applications, especially in drug design [4]. It is crucial to understand the process of self-assembly for the purposes of drug development, for example, recombinant ferritin-based vaccines.
In this work we investigated different oligomeric states of ferritin by small angle scattering (SAS) using recombinant protein complexes based on ferritin from H. pylori. We defined macro parameters such as Rg, Dmax and Vp for different fractions obtained by size-exclusion chromatography (SEC) the samples of ferritin exposed to highly basic pH.
We supposed that these macro parameters correspond to monomeric, dimeric and 24-meric states. In addition, there are evidences of an octomeric state of ferritin, but that part is underdiscussed in this report and requires some further investigation.
We acknowledge the support from the Ministry of Science and Higher Education of the Russian Federation (agreement # 075-03-2023-106, project FSMG-2021-0002).
Literature list
1. Self-Assembly of Ferritin: Structure, Biological Function and Potential Applications in Nanotechnology / S. Chakraborti, P. Chakrabarti // Adv Exp Med Biol. — 2019. — Vol. 1174.
2. Ferritin: design and formation of an iron-storage molecule / Ford G.C. et al // Philosophical Transactions of the Royal Society of London. B, Biological Sciences. —1984. — Vol. 304.
3. Structure and composition of ferritin cores isolated from human spleen, limpet (Patella vulgata) hemolymph and bacterial (Pseudomonas aeruginosa) cells / Mann S., Bannister J.V., Williams R.J.P. // Journal of molecular biology. — 1986. — Vol. 188.
4. Ferritin self-assembly, structure, function, and biotechnological applications / V.V. Sudarev, S.M. Dolotova, S.M. Bukhalovich et al. // International Journal of Biological Macromolecules. — 2023. — Vol. 224.
The production of nuclear energy, the use of diagnostic radiation or radiation treatment, or work in radiation- harmful conditions, including research laboratories, can cause human exposure. It is known that radiation exposure can have variety effects on the body, tissues, cells etc. There are many works concerning damage effect of ionizing radiation influence on the central nervous system as well. Our experiment was conducted to obtain a view of what may occur with behavior of laboratory animals using «Cerebrolysin» after irradiation in the long term. The Open field test, T-maze and the Morris water maze were used for behavioral analysis of experimental animals.
A spiral generator is a simple device that stores electrical energy at one, relatively low voltage, and discharges the stored energy in the form of a short electrical pulse with a higher voltage than the stored one. To increase the efficiency and normal operation of the generator, it is necessary that the impedance and response time of the key be much less than the impedance and time of passage of the signal along the strip line. To solve this problem, we made a long line of the spiral generator profiled. Meander-shaped cutouts are made on the two-bus line, which separate the inductive and capacitive parts of the generator along the axis in space. As a result of profiling, the wave impedance of a long two-tire spiral line is increased three times. The paper proposes a theoretical model for a generator with a space-separated inductive and capacitive part, examines the experimentally measured parameters of the generator, and makes a comparison.
The created compact generators of nanosecond high-voltage pulses are supposed to be used for the manufacture of portable pulsed X-ray machines with explosive electron emission.
A model of the α-cluster radioactivity of even-even nuclei is presented.
In this model, the collective motion in mass-asymmetry coordinate determines the probability to form a cluster in the surface region of the nucleus [1].
The tunneling in the coordinate of the relative distance between the centers of mass of the
cluster and the daughter nucleus determines the penetrability of the barrier of the nucleus-nucleus potential.
The calculations was performed in the two-potential approach [2].
The α-decay half-lives are calculated for various Ra, Th, U, and Pu isotopes. The fine-structure of alpha-decay, i.e. the relative yields of alpha-decay from the ground-state of the mother nucleus to the various yrast states of the daughter nucleus
is demonstrated on the particular examples of 〖^230〗Ra, (^232)Th and (^240)Pu.
[1] T.M.Shneidman, G.G.Adamian, N.V.Antonenko, R.V.Jolos, S.-G.Zhou, Phys.Rev. C 92, 034302 (2015).
[2] S.A.Gurvitz, Phys.Rev. A 38, 1747 (1988).
The analysis of electromagnetic radiation serves as a primary method for studying the Universe that surrounds us. The main mechanisms for the generation of electromagnetic waves by charged particles can be conditionally divided into bound-bound transitions (atomic and molecular), bound-free transitions (recombination of ions), and free-free transitions (bremsstrahlung radio emission of electrons flying near ions), see, for example, [1]. Additionally, both coherent and incoherent mechanisms of emission exist in the radio range, occurring in dense plasma (e.g., sporadic solar radiation) as well as in a vacuum (e.g., synchrotron radiation). The latter plays an enormous role in radio astronomy, and will be the focus of this discussion.
Without delving into what synchrotron radiation is, for the task at hand it is essential to remember two key aspects: first, the source of this radiation are relativistic electrons, and second, this radiation is polarized, see for example [2]. Such polarized radiation, propagating in a medium with an embedded magnetic field, experiences the Faraday effect—the rotation of the plane of polarization, proportional to the longitudinal component of the magnetic field along the line of sight and the length of the path traveled. Massive astrophysical scales, such as, for example, the thicknesses of galaxies and nebulae, compensate for relatively small magnetic fields and even where the minuteness of the fields does not allow for the detection of effects such as Zeeman splitting or Doppler broadening—the Faraday effect enables humanity's astrophysical "magnetometer" to probe deep into distant galaxies and nebulae. Of course, measuring cosmic Faraday rotation is a very complex and laborious procedure and, in particular, requires measuring the rotation of the plane of polarization not at a single wavelength, but at multiple wavelengths. However, astrophysicists, with the aid of modern radio telescopes, have learned to cope with many technical issues in observations of such nonthermal radio emissions [3].
The talk will focus on Burn's well-known formula [4], derived in 1966, for the polarization of synchrotron radiation from a flat galaxy as a function of wavelength. In this case, both the radiation sources and the magnetic field are located within the same region, making the computation of the plane rotation of polarization due to Faraday rotation slightly more complicated than for the classical Faraday screen through which light from a distant source passes. Nevertheless, the simplicity of the resulting formulas, a detailed mathematical derivation of which can be found in [5], has ensured the wide applicability of Burn's results for assessing astrophysical magnetic fields to this day. There are numerous works in this area, and it would be remiss not to mention significant contributions from distinguished scientists such as Richard Veilbinsky, Elli Berkhauzen, Rainer Beck, and Marita Krause. Using Burn's formula, these researchers have greatly contributed to our modern understanding of the Universe's magnetic field formation [6]. However, there is a serious issue with the universal applicability of Burn's formula. The problem is that not all magnetic structures in the Universe resemble a thin flat disk of constant thickness, making its default application to all objects for synchrotron radiation analysis a rather contentious decision.
Main Objective
The primary goal of this presentation is to show the extent to which Burn's formula is applicable (or rather, inapplicable) to objects significantly different from flat disks, particularly to galactic jets. Such jets are cylindrical structures protruding perpendicularly or at an angle from flat, disk-like, or spiral galaxies. According to modern theories, these areas are also saturated with magnetic fields, much like galactic disks, and contain relativistic electrons, consequently undergoing Faraday rotation of the polarization plane of synchrotron radiation as well. However, the geometry of jet regions, their azimuthal symmetry, and the complexity of the field lead to doubts about the applicability of Burn's formula even as a zeroth-order approximation. In the presentation, following the ideas of Burn and other authors, we will demonstrate the derivation of the dependencies of the degrees of polarization on the wavelength for synchrotron radiation in such cylindrical areas. We hope that this study will be of interest both from theoretical and practical viewpoints for applications not only to galactic jets but also to other objects of similar structure. The work has been supported by the BASIS Foundation Grant No. 21-1-3-63-1.
References
Ginzburg V.L., Syrovatsky S.I. // Cosmic Magnetobremsstrahlung (Synchrotron) Radiation // Advances in Physical Sciences. - 1965. - Vol. 87. - No. 9. - P. 65-111.
Schott G.A. // Electromagnetic radiation and the mechanical reactions arising from it: being an Adams Prize Essay in the University of Cambridge. - University Press, 1912.
Sokoloff D.D. // Measuring Galactic Magnetic Fields: From VL Ginzburg's book to Faraday Synthesis // Nature. - 2017. - No. 10. - P. 30-36.
Burn B.J. // On the depolarization of discrete radio sources by Faraday dispersion // Monthly Notices of the Royal Astronomical Society. - 1966. - Vol. 133. - No. 1. - P. 67-83.
Sokoloff D.D. et al. // Depolarization and Faraday effects in galaxies // Monthly Notices of the Royal Astronomical Society. - 1998. - Vol. 299. - No. 1. - P. 189-206.
Beck R. et al. // Galactic magnetism: recent developments and perspectives // Annual review of astronomy and astrophysics. - 1996. - Vol. 34. - No. 1. - P. 155-206.
An integral part of modern scientific research is collaboration on various types of documents. To organize and facilitate this work, various systems from the class of document management are typically employed. In this regard, the DocDB is used at the Joint Institute for Nuclear Research (JINR), and several independent instances of it for different projects are currently in operation. However, experience with the DocDB has shown that it does not fully meet the requirements of modern projects at the JINR. Therefore, there is a need for the development and enhancement of DocDB, but due to the system's outdated technological foundation does not allow the use of modern technologies in the development and this process becomes exceedingly complex and time-consuming. In this work, based on our experience of using DocDB, we present the development and prototype of a new platform called “SciDocCloud”.
Modern technically sophisticated facilities need tools that provide a way to keep logbooks of the events and activities, during both commissioning and operations. This talk describes a new electronic logging system currently being developed at the MLIT for use in the accelerator complex of LHEP. A prototype logbook based on the developed system is introduced, highlighting its primary functional features and identifying plans for further development. Although at this stage the project is primarily taking into account requirements of the LHEP Accelerator Department the system is customizable and quite universal so it can be used freely in other projects.
In this work we present the results of the study of components for a future modular reactor antineutrino detector which use inverse beta decay reaction for antineutrino detection and based on solid-state plastic scintillator and lithium scintillator for neutron capture $^{6}$Li$_{2}$CaSiO$_{4}$ . Studies of samples of plastic scintillators have been carried out: estimates of the energy resolution and light collection inhomogeneity have been obtained; for the $^{6}$Li$_{2}$CaSiO$_{4}$ scintillator, an estimate of the neutron capture efficiency and energy resolution have been obtained. We also present the results of Monte Carlo simulations performed using the GEANT4
The Spin Physics Detector is an experiment at NICA designed to study the spin structure of the proton and deuteron and other spin-related phenomena using polarized beams. Two Beam-Beam Counters (BBCs) will be installed symmetrically aside from the interaction point in the end-cups of SPD setup and will serve as a tool for beam diagnostics including local polarimetry. The outer part of the BBC wheel is based on fast scintillator tiles and cover the polar angels between 60 and 500 mrad.
In this talk, we discuss testing different materials configurations for the BBC prototype based on scintillator tiles. The light collection depends on material combinations - different fibers (Saint Gobain BCF91AS, BCF92S, and Kuraray Y-11), different ways of covering tile surface (Matted and double covered with Tyvek sheets tiles), as well as different optical cements (CKTN mark E, OK-72) were used in the study. SensL 1x1 mm2 SiPM readout provides an opportunity to measure light collection dependence with high energy resolution using radioactive source and cosmic rays.
Развитая инфраструктура и наличие пучков тяжелых ионов нужных энергий способствовало Ускорительному комплексу NICA (ЛФВЭ ОИЯИ г. Дубна МО) стать уникальным местом для проведения международного физического эксперимента SRC – измерения короткодействующих двухнуклонных корреляций в обратной кинематике. Проведение эксперимента невозможно без жидководородной (протонной) мишени. В статье приводятся цели и требования к реализации эксперимента, в особенности требования к выведенному пучку и мишени. А также условия и результаты проведённых физических сеансов эксперимента SRC на спектрометре BM@N 2018 года на жидководородном мишени с гелиевым охлаждением и 2022 на мишени с криорефрежираторным охлаждением.
The longitudinal coordinate of origin of the photon produced in collider experiment is usualy relatively poorly measured. Therefore in case of diboson production in pp collisions there is the distinct possibility that some events of interest passing the final selection in data are actually from two overlapping hard scatter processes, else pile-up background.
In this study a Monte-Carlo-based estimate of this background source is performed. Pile-up events are built by overlaying the separate simulations of single photon production and single Z boson production at particle-level. Finally, the number of such background events in the region of interest can be obtained by applying detector efficiencies.
Baikal-GVD is a large (∼1 km3) underwater neutrino telescope located in Lake Baikal, Russia. This paper presents a neural network for separating events caused by extensive air showers (EAS) and neutrinos. By choosing appropriate classification threshold, we preserve 90% of neutrino-induced events,while EAS-induced events are suppressed by a factor of 10-6. A method for estimating the neutrino flux with minimal error based on neural network predictions has also been developed. The developed neural network employ the causal structure of events and surpass the precision of standard algorithmic approaches.
The Baikal-GVD online data processing and alert system was launched at the beginning of 2021. It is designed for fast online neutrino event reconstruction and, when a potential signal from an astrophysical source is detected, sending an alert message to collaboration members. It also searches for matches between internal alerts and other astrophysical experiment alerts. This contribution describes improvements to the alert system related to alert visualization that will help better understand the alert data and its possible relation to astrophysical phenomena. The architecture of the databases used to store the alert data (MariaDB, InfluxDB, MongoDB) is described. Automation of data analysis and visualization processes occurs using specialized Python libraries (Matplotlib, Astropy, etc.), which provide various opportunities for this. The capabilities of the Grafana software system for storing visualized data with the ability to share are also being explored.
The measurement process in the deterministic de Broglie-Bohm theory is investigated. The simplest devices for measuring coordinates and momentum are modeled, while both the measurement device and the quantum system are described by the same unified laws. Thus, the problem with the probability distribution in the momentum space, posed in the works \cite{kurt,naun,heim}, is solved. The trajectories of de Broglie particles are calculated numerically. The restoration of the Heisenberg uncertainty principle is verified when the coordinate and momentum are measured alternately.
The anapole moment is an electromagnetic moment in the decomposition of the vector potential of the current distribution resulting from spatially odd interactions. The study of the anapole moment will give impetus to the development of the theory of spatially odd interactions in the nuclei of atoms.
To date, no experiments have been carried out to determine the anapole moment with sufficient accuracy, and the purpose of this work is to calculate the coefficient of the anapole moment's enhancement in SiO⁺ molecule within the framework of fully relativistic approaches to describing multielectronic systems. The obtained value can be used in an experiment to determine the anapole moment in SiO⁺ molecule.
Two LiInSe2 single crystals, grown under different conditions, have been studied. Characteristics of these crystals for neutron detection have been compared using scintillation detection method due to the neutron capture by lithium nuclei and subsequent emission of charged particles and the conventional method of charge extraction from single-crystal surfaces due to the same nuclear reaction. Prospects of application of LiInSe2 single crystals for neutron detectors of different types are discussed.
The scientific community knows a number of methods for quantizing various systems. So, depending on the input data and frame of the problem, you can choose the most suitable one. Deformation quantization in this case is a convenient tool when we are talking about a smooth manifold with a given dynamic structure. Such structures arise naturally if we consider the Hamiltonian formulation of the classical theory, where the concept of the Poisson bracket is introduced. The application of deformation quantization was first applied by Fedosov to symplectic manifolds, which are analogues of dynamical systems with only the second-class constraints. The most breakthrough work in the area under discussion was Kontsevich's work on deformation quantization of Poisson manifolds, where an elegant geometric approach to solving this problem was presented.
Further extension of the construction to presymplectic manifolds showed that the sequential construction raises cohomological obstruction, the overcoming of which is a difficult and complex task. While in the simplest case of presimplectic manifolds, where there is only one first-class connection, the obstruction have a good physical interpretation. These obstruction can be understood as classes of physical observables that cannot be raised to the quantum level. The geometric interpretation of these invariants is illustrated in this work.
In the work gravitational wave conversion to electromagnetic wave during propagation in external magnetic field is considered for expanding FLRW universe. Initially, only tensor mode is present in the problem and then it propagates in the medium with a magnetic field - cosmological magnetic field for example. System of differential equations are derived for tensor and scalar modes of gravitational perturbations and for two polarizations of electromagnetic wave. After that the system is analyzed mathematically and from the physical point of view. In the end the author makes a conclusion about possible influence of the considered phenomenon on relic gravitational wave spectra.
One of the main goals of developing a new multi-energy X-ray tomograph is the recognition of materials using spectral information. The Medipix and Timepix series detectors are one of the pixelated semiconductor hybrid detectors developed in Medipix collaboration. These detectors have high spatial resolution and are capable of detecting radiation over a wide energy range. It makes possible to use this detectors in multi-energy computed tomography.
This work demonstrates the possibility of using the Medipix3RX and Timepix3 detectors to obtain energy information that can be used to distinguish various substances in multi-energy tomography. Some results of applying the developed criterion for identifying contrast agents on phantom objects containing various concentrations of elements with a high Z number, such as La, Nd, Gd and I, are also presented. This criterion was tested based on the energy information presented in the form of 2D images and 3D reconstructions. The criterion also allows one to evaluate the concentrations of contrast agents in the studied samples.
This research was funded by the Russian Science Foundation, grant number 22-15-00072.
Small-angle neutron scattering (SANS) is a particularly powerful method that makes it possible to study inhomogeneities in the volume of macroscopic samples at scales from several to several hundreds of nanometers. Magnetic SANS is used to study a wide range of magnetic materials, including amorphous metals, nanocrystalline hard and soft magnetic materials [1]. Scattering occurs due to the interaction of the magnetic moment of neutrons with the distribution of internal magnetic field, created by the spatially inhomogeneous magnetization in the material. Thus, to interpret the scattering cross sections, it is necessary to understand formation of the magnetic structure and its dependence on the inhomogeneity of the material and the external magnetic field. The distribution of magnetization on such a scale is described by the theory of micromagnetism, which is the main tool for interpreting SANS cross sections. Such a combination of neutron scattering theory and micromagnetism, called the micromagnetic SANS theory, has already shown its effectiveness in explaining the magnetic properties of macroscopically anisotropic multiphase magnetic systems with weak inhomogeneity of saturation magnetization and magnetic anisotropy [2]. An example of such a system could be a macroscopically anisotropic (e.g. subjected to field annealing) nanocrystalline ferromagnet. In such materials, in addition to local (random) magnetic anisotropy, there is a global (macroscopic) anisotropy, which may be due to mechanical stresses caused by external pressure, or internal stresses arising from the inhomogeneity of the structure, chemical or phase composition of the material. The report presents several examples of successful application of this theory to various nanocrystalline systems, as well as an extension of the theory taking into account possible inhomogeneity of macroscopic uniaxial anisotropy. It is shown that in high magnetic fields the inhomogeneity of the global anisotropy affects the scattering pattern only when the anisotropy direction vector has a component along the axis of the applied external field.
In this work, the influence of the first forbidden beta transitions on the accuracy of reconstruction of cumulative reactor antineutrino spectra of uranium and plutonium fission products by conversion of the corresponding cumulative beta spectra is investigated. It is shown that the most reliable way to account for forbidden transitions is a direct ab initio calculation of the forbidden component of cumulative spectra and subsequent conversion of the permitted component. It is found that the ratio of cumulative spectra is stable to variations in the conversion procedure associated with the introduction of forbidden transitions.
The Double Chooz experiment has obtained its most precise measurement of the neutrino mixing angle θ13 so far exploiting for the first time its multi-detector (far and near) configuration. The improvement of this value relies on the increase of statistics as well as a major reduction of reactor and detection systematics thanks to the iso-flux configuration and a novel detection technique, called "Total neutron Capture". This new method enhances neutrino detection by exploiting the neutron captures on all available nuclei (Gd-n, H-n C-n) resulting in the increase of the detection volume by the factor of 3 and reduction of some major systematics. The main analysis carried out to perform the latest measurements will be presented, as detailed in latest publication in Nature Physics 2020: “First Double Chooz Measurement via Total Neutron Capture Detection”
The work presents approaches to estimation temperature effects occurring in the reactor core. Rough approximations for fuel assemblies and core design are considered.
The effect of neutrino quantum decoherence has been studied actively in recent years (see [1-3] and references therein). In our present paper we consider the interaction with an arbitrary reservoir in thermodynamic equilibrium. We have found that within a fairly wide class of theoretical models the parameters of neutrino quantum decoherence are proportional to the neutrino decay rates into a massless particle and light neutrino state. The effect of neutrino quantum decoherence can play a role in neutrino evolution during supernova explosions and in other astrophysical environments.
References
[1] A. Lichkunov, K. Stankevich, A. Studenikin, M. Vyalkov. Neutrino quantum decoherence engendered by neutrino decay to photons, familons and gravitons, J.Phys.Conf.Ser. 2156 (2021) 1.
[2] K. Stankevich and A. Studenikin. Neutrino quantum decoherence engendered by neutrino radiative decay. Phys.Rev.D 101 (2020).
This work is devoted to finding the optimal design of an Outer Veto for the DarkSide-20k experiment being built in the Gran Sasso National Laboratory (Italy). The DarkSide-20k experiment seeks to directly detect dark matter in the form of weakly interacting massive particles (WIMPs). The DarkSide-20k detector is a two phase time projection chamber (TPC) filled with 50 tons of underground liquid argon (UAr). The liquid argon (LAr) is used as a scintillator in the experiment. The TPC is located inside a stainless steel vessel. In the space between the membrane cryostat and the stainless steel vessel, it is planned to place the Outer Veto structure. The membrane cryostat is planned to be filled with 650 tons of atmospheric argon (AAr). Thus, AAr will be the scintillator for an Outer Veto. The task of the Outer Veto is to register background events from cosmogenic muons and associated nuclear-active showers that can activate isotopes and can produce high-energy neutrons. The optimal optical model is selected by conducting optical simulations and calculating the light yield. Design parameters are chosen to optimize the light yield Optical simulations were performed with a Geant4-based framework.
The influence of various design parameters on the light yield of the Outer Veto is presented.
Periodic Pulsed research reactors The IBR-2 type in Dubna is the most effective source of slow neutron extracted beams for studying various structures by diffraction, small-angle scattering, reflectometer, inelastic scattering, and neutron diffraction, due to a short neutron pulse and a high average flux of up to 10 E + 14 cm2 s-1. At the same time, due to the specificity of the kinetics, fluctuations in the power energy of pulses in such a reactor are tens of times higher than in stationary reactors and create problems for the control of the apparatus. This paper proposes and substantiates a method for a significant reduction in the level of fluctuations in power pulses of such reactors using the example of the IBR-3 (NEPTUNE) pulsed reactor project with the threshold Np-237 isotope as a nuclear fuel.
Soil plays important role in food production, as well as participates in regulating the chemical composition of the atmosphere, so accurate determining the concentration of different chemical elements in soil today remains an important task for various fields of science.
Nowadays, it seems promising to determine the concentration of different chemical elements in the soil using so-called neutron-gamma analysis on fast neutrons. This method is based on neutron irradiation of the material and analysis of the spectra of gamma quanta. By the area of the characteristic gamma peaks, it is possible to determine the amount of a particular substance in the sample. The system used for such analysis, consists of a neutron source, a gamma detector (detectors) and data collection systems.
An important task in the development of a prototype device for analysis is to create a qualitative model of the designed system. This model can be done in the Geant4, a toolkit that models the passage of elementary particles through matter using the Monte Carlo method. This work involves computer modeling of the setup for analysis of soil sample in toolkit Geant4.
The purpose of my research work is a computational and theoretical
justification of the design of a laboratory source for modeling
astrophysical phenomena associated with superluminal EMR sources.
An
elliptical emitter based on a photodiode with laser initiation was chosen as the basis for a generator that would allow us to simulate the phenomena of interest
to us. [RF Patent No. RU2738959C1. Generator of electromagnetic pulses-
sov. Bukin V. V., Garnov S. V., Dolmatov T. V., Terekhin V. A., Trutnev Yu. A.
№ 2020117632. Announced on 05/15/2020. Published on 12/21/2020. Byul. No. 36.]
$ Kildiyarov$ $ T.V.^1, Galkina$ $S.V.^{2,3}, Lugovtsov $ $ A.E.^4, Sveshnikova $ $ A.N.^{1,2,3} $
$ $
$^1$FFPCE Lomonosov MSU, Moscow, Russia
$^2$CTP PCP RAS, Moscow, Russia
$^3$FRCC PHOI, Moscow, Russia
$^4$FP Lomonosov MSU, Moscow, Russia
e-mail: kildiyarovtv@my.msu.ru
$ $
Any living system must continuously exchange energy, matter, and information with the environment, for which a system for interpreting information within the cell is necessary. One of the important mechanisms for the transmission of information from external stimuli into the cell is the system controlling the intracellular calcium ($[Ca^{2+}]$) level as this ion easily binds to proteins and alters their functions. Platelets are anucleate cellular fragments whose functions are mostly controlled by $[Ca^{2+}]$ [1]. Therefore, studying the mechanisms of how cells interpret information about their surrounding environment is conveniently done in platelets.
In the present study, we investigated the issue of spatial heterogeneity of $[Ca^{2+}]$ in platelets. For experimental observation of $[Ca^{2+}]$, platelets were incubated with fluorescent probe CalBryte 590 AM (AAT Bioquest, California, US). Fluorescent probes were excited by a laser at 561 nm wavelength. Nikon Eclipse Ti-E microscope with a CFI Apochromat TIRF 100XC Oil objective with 100-fold magnification and numerical aperture of 1.49 was used in this study. The soft ImageJ with Fiji package and Python 3.10 was used for interpretation of the experimental data. To describe the obtained data, a computer model of calcium signaling was developed which is a reduced model of De Young-Keizer which is augmented by the diffusion equation [2]. The Neumann closed boundary conditions were imposed at the boundaries of the cytoplasm. The model integration was performed using finite-volume method in Python 3.10 environment.
Experimentally, a wave of $[Ca^{2+}]$ is observed in single immobilized platelets of healthy donors, and the wave front propagates with speed
$ 31.6 ± 5.7$ $ nm/s $. The computer model produces conditions in which a wave of $[Ca^{2+}]$ is also observed, but its rate decreases with time from $ 147 $ to $ 30$ $nm/s$. The corresponding diffusion coefficient of calcium ions was set at $5.3$ $µm^2/s$, which is less than $ 20-100$ $µm^2/s $ found in the literature [3]. Thus we can conclude that the driving mechanism for spatial heterogeneity of $[Ca^{2+}]$ in the platelet is the slow diffusion of ions in the cytoplasm.
$ $
The work was supported by SES «Photonics and digital medicine» 23-Ш06-03.
References:
1. Shakhidzhanov S.S. et al. Calcium oscillations in blood platelets and their possible role in ‘interpreting’ extracellular information by cells // Physics-Uspekhi. Uspekhi Fizicheskikh Nauk, Russian Academy of Sciences and IOP Publishing, 2019. Vol. 62, № 7. P. 660.
2. Keizer J., Young G.D. Simplification of a Realistic Model of IP3-induced Ca2+ Oscillations // Journal of Theoretical Biology. 1994. Vol. 166, № 4. P. 431–442.
3. Donahue B.S., Abercrombie R.F. Free diffusion coefficient of ionic calcium in cytoplasm // Cell Calcium. 1987. Vol. 8, № 6. P. 437–448.
The problem of the release of metal nanoparticles into the environment is becoming very relevant. Increasing production and consumption of nanomaterials leads to pollution of aquatic and terrestrial ecosystems, creating human health and safety risks. Calendula officinalis plants, which are valuable plant raw materials for medicine and pharmaceutics, were chosen as the object of research. The features of silver, gold and copper nanoparticles translocation and accumulation in the segments of Calendula officinalis under root irrigation conditions were investigated. During a 28-day experiment, plants were exposed to metal nanoparticles in a concentration range from 1 to 100 mg/L. The proton-induced x-ray emission (PIXE) method was used to determine the gold and silver content in plant and soil samples, while ICP-OES was used to determine copper content. Using transmission electron microscopy, the size and shape of nanoparticles were determined.
The content of gold after exposure to nanoparticles with the size of 1–5 nm increased proportionally with increasing concentrations of AuNPs solutions in all plant segments and soil. The content of silver (size of nanoparticles 4-5 nm) in roots, stems, leaves, flowers and soil was depended on the concentration of the nanoparticles in solutions. The maximum content was determined in the soil and aerial parts of plants when a solution of 100 mg/L was used. Copper nanoparticles with the size 15-70 nm were mainly accumulated in the soil. However, a fivefold increase of copper content in flowers and root systems compared to the control was observed.
The results of this study indicate the uptake of gold, silver and copper nanoparticles in plants under conditions of root exposure and present big interest for plant nanotoxicological studies.
The BM@N experiment is the first working installation at the NICA collider complex. The aim of the experiment is to study the properties of baryonic matter in the collision of heavy nuclei with a fixed target. During a physical session in December 2022-February 2023, about half a billion Xe nuclei interaction events with a stationary CsI target were collected. For correct processing of experimental data, it is necessary to know exactly the positions in the space of the detectors of the experimental setup.
The initial detector positions are determined from knowing the geometry as it is described the techical design of the detector. The uncertainties on the positions of the detector elements, introduced during assembly, can worsen the accuracy of hits reconstruction in the detector. The alignment procedure corrects the those initial position values, so they are consistent with the actual detector elements placement.
The goal of the work is to perform the alignment procedure for TOF-400 detector at BM@N after the physical session, using the collected experimental data. The method applied is analyzing distributions of residuals versus tangents of track entry angles for every plane of TOF-400, and there are 20 planes in total. Using this method, one can obtain misalignment value of planes along beam axis. The result of the TOF-400 alignment procedure is presented and discussed.
Correlation femtoscopy allows one to estimate the spatial and temporal characteristics of the particle-emitting region formed in the relativistic heavy-ion collisions. Azimuthally-differential analysis is used to study shape and orientation of the source. In this work, collisions of isobaric nuclei Ru+Ru and Zr+Zr at $\sqrt{s_{NN}} = 200$ GeV are calculated using the UrQMD (Ultrarelativistic Quantum Molecular Dynamics) model and the azimuthally-differential two-pion femtoscopy relative to the second- and third-order event plane are performed. The extracted characteristics of the emission source are presented as a function of the pair transverse momentum, $k_{T}$, collision centrality and the pair emission angle. In the future, the obtained results can be compared with the STAR experimental data.
In magnetic fluids, when exposed to a magnetic field, optical effects are observed: birefringence, dichroism, changes in optical density, change of the intensity of scattered light, and others. The nature of these effects depends on the particle size, size distribution, chemical composition, solid phase concentration, temperature, etc. Studying the influence of magnetic particle aggregates on optical effects that are sensitive to the polarization of light is important and interesting. The purpose of this study is to study the features of the effects of birefringence and dichroism in magnetic fluids with different aggregative stability.
We studied two magnetic fluids with magnetite nanoparticles in kerosene. Sample No. 1 was resistant to the formation of aggregates. The average radius of magnetite particles is 6.7 nm. Sample No. 2 was aggregatively unstable. The average radius of magnetite particles is slightly larger, around 13.7 nm. In sample No. 2, when exposed to a magnetic field of about 8 kA/m, aggregates with sizes of 60-80 nm are formed. In sample No. 1, no aggregates are formed in the same field. We examined samples of these magnetic fluids diluted to a volume concentration of 0.01%.
We studied dichroism and birefringence in the samples using the Ellipse-1891 spectral ellipsometric complex. The samples were placed in glass cuvettes 5 mm thick. The magnetic field was created by an electromagnet mounted on the object stage of an ellipsometer. We measured the ellipsometric parameters $\psi$ and $\triangle$ in transmitted light. We also measured the dependence of these parameters on the wavelength of light and the magnetic field strength. Based on the ellipsometric parameters, we calculated the characteristics of birefringence and dichroism using the formulas:
$\triangle k=k_{\parallel}-k_{\perp}=\frac{\lambda}{2l\pi}\ln\tan\psi$
$\triangle n=n_{\parallel}-n_{\perp}=\frac{\lambda}{2l\pi}\triangle$
where $k_{\parallel}$ and $k_{\perp}$ are light attenuation coefficients, and $n_{\parallel}$ and $n_{\perp}$ are the refractive indices of light for rays polarized parallel and perpendicular to the field, λ is the wavelength of the incident light, l is the thickness of the magnetic fluid layer.
Figure 1 shows the birefringence spectra for the samples. Characteristic features of the spectra are the presence of a maximum of the birefringence effect at a wavelength of 490 nm, which becomes more pronounced with increasing magnetic field strength. The graph shows that in sample No. 2, which is less resistant to the formation of aggregates, the magnitude of the birefringence effect is 2.5 times greater than in sample No. 1.
Figure 2 shows the dichroism spectra for the samples. The spectra have a pronounced maximum in the region of 470-480 nm and a minimum in the region of 740-750 nm. The action of a magnetic field changes the dichroism spectra. In sample No. 1, the effect of the field makes the minimum in the region of 750 nm more pronounced and increases the amplitude of the maximum in the short-wave region, and in sample No. 2, an increase in the field leads to an increase in dichroism in the near-IR region and the almost complete disappearance of the minimum in this region. The increase in dichroism in the long-wavelength region in sample No. 2 is much more significant than in the short-wavelength region.
We believe that the observed features of the birefringence and dichroism spectra depend on the presence of nanoparticle aggregates in the samples. This is especially noticeable in dichroism spectra. We believe the reason for this is the strong dependence of the light attenuation coefficient on particle size. Our estimates give the ratio of light attenuation cross sections for 14 nm and 70 nm particles as 1:270. Particle aggregation affects the birefringence spectra only slightly. The observed differences can be explained by different particle sizes in samples No. 1 and No. 2.
An analysis of reliability of existing experimental (EXFOR database) and evaluated (TENDL-2021 and IRDFF-II libraries) cross section data for $(\mathrm{n},\,2\mathrm{n})$, $(\mathrm{n},\,\mathrm{n}'\gamma)$ and $(\mathrm{n},\,\mathrm{p})$ reactions initiated by neutrons with energies up to 20 MeV with the formation of ${}^{114,115}\mathrm{In}$ and ${}^{91}\mathrm{Y}$ isotopes in isomeric metastable states is performed. This examination is motivated by the results of recently carried out measurements at the National Research Centre “Kurchatov Institute” with neutrons with energies close to 14 MeV: these data are important for designing facilities suitable for controlled thermonuclear fusion. An independent method based on TALYS-1.9 software package calculations using parameters provided in RIPL-3 library for evaluating both the cross sections of mentioned reactions and the errors for such evaluations is proposed. Implemented error of the cross section evaluation allows for realistic conclusions about the reliability of data obtained in various experiments to be drawn.
BM@N is a fixed-target experiment aimed at studying of heavy ion collisions at beam energies up to 4 A GeV. The new High Granular Neutron detector (HGN) is being developed for this experiment. This detector will be able to carry unique measurements of flow of the neutrons. Due to these measurements it will be possible to explore the isospin degree of freedom of the QCD phase diagram.
This talk is devoted to the algorythm of cluster recognition and determination of energy of the neutrons in the HGN. The proposed methods are checked by Monte-Carlo simulation and using data from the prototype of the HGN detector collected in Xe+CsI collisions in the beginning of 2023 at beam energy 3.8 A GeV.
Experimental justification of the equation of state of nuclear matter at extreme densities is rather difficult under terrestrial conditions, and therefore studying of neutron stars remains valuable. For a long time, the main testable quantity was the maximum mass of a neutron star. In 2017, the gravitational signal from the merger of neutron stars was detected and a new characteristic, tidal deformability, was measured. The tidal deformability coefficient is defined as the proportionality coefficient between the external tidal field and the quadrupole moment of the star.
In this work, we calculated the dependence of mass on radius of neutron star and the tidal deformability for various equations of state of nuclear matter, taking into account the presence of hyperons Y in matter in addition to neutrons, protons, electrons and muons.
Particular attention in our calculations is paid to the description of many-body effects. Using Skyrme interaction we show that in the case of neutron stars, three-body YNN forces are not equivalent to YN density-dependent forces. And since these forces play a key role at high densities, they strongly influence the maximum mass of neutron stars and, in particular, the density at which hyperons appear. Thus, we consider the dependence of the hyperon appearance point on properties of baryonic interactions and its influence on the different characteristics of neutron stars.
The work is devoted to the creation of an automatic frequency control system for the harmonic station RF3 of the NICA collider. The special attention was paid to the main tasks and the algorithm of the station’s work. Based on the studied modes of station’s operation, a program for generating control pulses was developed, they use for moving the tuners which set up the station to the resonant frequency. The created program was debugged and integrated into the general project.
Halobacterium salinarum is a rod-shaped motile extremely halophilic archaea, capable of living in saturated salt solutions. It is believed to be extremophile as its natural habitat is characterized by extreme UV radiation and inconsistent nutritional conditions. Although Halobacterium salinarum is an aerobic chemoorganotroph, it can also survive in anaerobic conditions by utilizing light energy. It becomes feasible due to the large amount of bacteriorhodopsin (BR), which transduces light energy to generate proton gradient for ATP synthesis, in their membranes (Eichler, 2023). Bacteriorhodopsin is known to form 2-dimensional clusters in the native membrane; such membrane fraction carrying BR is called purple membranes (PMs). PMs isolated from Halobacterium salinarum features BR:lipid weight ratio up to 4:1 (Oesterhelt & Stoeckenius, 1974). The other native membrane fraction is red membranes, rich with caronenoid bacterioruberin.
Cultivation of Halobacterium salinarum has a significant value both for scientific and practical applications: biomass with anti-oxidative and radio protective properties can be used as dietary additives, cosmetic bioactive compounds and others; BR is a promising material for information storage systems, optical switches, ultra-speed light detectors, etc. (Kalenov et al., 2016). Moreover, PMs are used as a model object for membrane proteins crystallization optimization, e. g. for investigation of morphological transformations in crystallization matrix and mechanisms of membrane fusion (Bogorodskiy et al., 2015; Murugova et al., 2022).
As long as PMs are of interest to our further research, in this work we investigated the influence of growth conditions on the resulting purple/red membranes ratio in two different Hbt. salinarum strains. First of the used strains was SGS (Kalenov et al., 2016), the second – S9. The used protocol of cultivation in flasks with minor changes (Kalenov et al., 2016) implies the addition of adsorbents, such as activated charcoal, to the growth medium. Hbt. salinarum were grown at +42℃ in the presence of light. In this study we compared cultivation of both strains with and without charcoal in the medium in terms of the biomass colour. While other conditions were the same, in the presence of charcoal SGS strain had purple colour, S9 strain – reddish; in the absence of charcoal both strains were reddish.
Activated charcoal has a positive effect on BR synthesis as it adsorbs metabolites, inhibiting cell growth, and products of oxidative stress, inducing carotenoid synthesis. As a result, it helps to obtain a larger amount of cells that express less carotenoids, therefore, purple/red membranes ratio increases. Our investigation shows, that in case of S9 strain such approach does not allow to achieve prevalence of PM fraction, though in case of SGS strain it is effective.
This research in supported by the Russian Science Foundation (grant No. 23-74-01076).
Bogorodskiy, A., Frolov, F., Mishin, A., Round, E., Polovinkin, V., Cherezov, V., Gordeliy, V., Büldt, G., Gensch, T., & Borshchevskiy, V. (2015). Nucleation and Growth of Membrane Protein Crystals in Meso - A Fluorescence Microscopy Study. Crystal Growth and Design, 15(12), 5656–5660. https://doi.org/10.1021/ACS.CGD.5B01061/SUPPL_FILE/CG5B01061_SI_003.AVI
Eichler, J. (2023). Halobacterium salinarum: Life with more than a grain of salt. Microbiology, 169(4). https://doi.org/10.1099/MIC.0.001327
Kalenov, S. V., Baurina, M. M., Skladnev, D. A., & Kuznetsov, A. Y. (2016). High-effective cultivation of Halobacterium salinarum providing with bacteriorhodopsin production under controlled stress. Journal of Biotechnology, 233, 211–218. https://doi.org/10.1016/J.JBIOTEC.2016.07.014
Murugova, T. N., Ivankov, O. I., Ryzhykau, Y. L., Soloviov, D. V., Kovalev, K. V., Skachkova, D. V., Round, A., Baeken, C., Ishchenko, A. V., Volkov, O. A., Rogachev, A. V., Vlasov, A. V., Kuklin, A. I., & Gordeliy, V. I. (2022). Mechanisms of membrane protein crystallization in ‘bicelles.’ Scientific Reports 2022 12:1, 12(1), 1–17. https://doi.org/10.1038/s41598-022-13945-0
Oesterhelt, D., & Stoeckenius, W. (1974). Isolation of the cell membrane of Halobacterium halobium and its fractionation into red and purple membrane. Methods in Enzymology, 31(C), 667–678. https://doi.org/10.1016/0076-6879(74)31072-5
Introduction
The presented design describes a prototype of an application specific integrated circuit (ASIC) for use with silicon microstrip sensors of the BM@N (Baryonic Matter at Nuclotron) facility [1] at the upcoming NICA collider.
The structural diagram, developed layout, and main electrical parameters of the ASIC are presented.
The prototype ASIC includes all the main complex functional blocks of the future full-scale version of the ASIC. For the fabrication of the chip a CMOS process of 180 nm node was chosen.
ASIC structure
The particles passing through the microstrip sensors create a charge on the strip by knocking out electrons or holes. The task of the chip is to amplify the signal, shape it, perform signal amplitude sampling and digitize it for all strips, and finally transmit this information outside via the SLVS interface. Figure 1 shows a simplified structural diagram of the presented microchip.
Fig. 1. Block diagram of the prototype ASIC
The prototype ASIC has 8 working + 2 additional outermost (test) analog channels for readout signals from microstrip sensors. Each channel consists of such blocks as a low-noise charge-sensitive amplifier (CSA), a time-variable amplifier-shaper with conversion times of 200-300-500 ns (SH), a polarity switching key (SW).
Blocks of a comparator (CMP) and a peak detector (PD) define the presence of a channel signal and retrieve the channel peak amplitude.
The threshold value for CMP is set by a 4-bit digital-to-analog converter (DAC). The duration of the CMP signal is determined by the time above the threshold. PD is supplemented with an auxiliary comparator circuit that provides signal type of peak find (PF) and reset the charge of the storage capacitor by Reset_PD signal.
The chip also includes an input calibration system based on 8-bit DAC. Calibration is performed by a digital slow control block, and data is written to it via the SPI interface.
ASIC is a prototype for its future full-scale 128-channel version. The close functional analog of this prototype chip is STS XYTER [2,3]. Since the maximum signal frequency is 100 kHz, one 8-bit ADC is used to successively process all channels.
Figure 2 shows the layout of the prototype ASIC. The main blocks are depicted on it. It has geometric dimensions of 5000 μm * 5000 μm. The contact pad frame contains 158 pads.
Fig. 2 Placement of blocks on the ASIC layout
The layout is planned to be used in an unpackaged version In addition to the signal path, the microchip includes test structures for optimizing subsequent ASIC launches. The digital block was also designed with the ability to upscale it to a 128-channel chip version. The main characteristics of the chip are given in table 1.
Table 1
Reference
[1]: Materials of the BM@N experiment website: https://bmn.jinr.ru/
[2]: K. Kasinski, W. Zubrzycka, Test systems of the STS-XYTER2 ASIC: From wafer-level to in-system verification», Proceedings of SPIE – International Society for Optical Engineering 2016 (Vol. 10031), doi: 10.1117/12.2249137
[3]: R. Kleczek, Analog front-end design of the STS/MUCH-XYTER2 - full size prototype ASIC for the CBM experiment, J. Instrum. 12 (1) (2017) C01053, doi:10.1088/1748-0221/12/01/C01053
The paper presents the main stages of creating a data acquisition system from a gas one-dimensional position-sensitive detector with a resistive anode wire based on the SciCompiler, and also gives a brief overview of the SciCompiler software package and the DT5560SE digitizer from CAEN.
The effect of neutron radiation on the optical and electronic properties of doped heterostructures with an AlGaAs/InGaAs/GaAs quantum well is experimentally studied. The effect of neutrons on the degradation of electron concentration and mobility, as well as on changes in the photoluminescence spectra of heterostructures, is discussed.
This paper investigates the effect of the magnetic component of microwave radiation on the dynamics of the electric current and magnetization of the Josephson junction φ0. Previous studies show that exposure of SFS junctions to radiation leads to a number of interesting phenomena that can be utilized in future electronic devices. We have used the Landau-Lifshitz-Hilbert equation and the resistive-capacitance shunt transition model to describe the coupled dynamics of the ferromagnetic magnetic moment and electric current in the presence of external radiation. The resulting system of nonlinear equations has been investigated numerically. It is shown that the magnetic component of external radiation leads to the appearance of integer and semi-integer current steps in the IV characteristics, splitting of the magnetization resonance peaks and the appearance of new frequencies in the magnetization dynamics spectrum. A dip in the resonance magnetization curve, the area of which coincides with the current step in the IV characteristic, is also observed. The mechanism of magnetic moment precession and IV characteristics at different parameters of φ0 transition and microwave radiation are investigated.
The Friedberg-Lee-Sirlin (FLS) model is a well-known renormalizable theory of scalar fields that provides for the existence of non-topological solitons. Since this model was proposed, numerous works have been dedicated to studying its classical configurations and its general suitability for various physical problems in cosmology, quantum chromodynamics, etc. In this paper, we study how Q-balls in effective field theory (EFT) reproduce non-topological solitons in full FLS theory. We obtain an analytical description of the simplified model and compare results with numerical calculations and perturbation theory. We also study the condensation of charged bosons on the domain wall. A full numerical solution allows us to check the EFT methods for this problem. The latter analysis is based on the application of EFT methods to significantly inhomogeneous configurations. We give an interpretation of the results in terms of the shifted boson mass and the vacuum rearrangement.
ALICE3 is a next-generation heavy-ion experiment at the Large Hadron Collider, a successor of the ALICE experiment. It opens a high-precision domain of the strongly interacting matter studies. A set of measurements of the ALICE3 requires electron identification with high efficiency and purity, which will be performed by several complementing experimental techniques. Feasibility of electron identification using electromagnetic calorimeter clusters matched with tracks reconstructed in the central tracker is studied withing the ALICE3 simulation and analysis framework. Electron identification criteria are optimized against efficiency and hadron contamination suppression, and applied to charmonium (1P) reconstruction in pp collisions via the $\chi_{cJ} \rightarrow J/\psi + \gamma$ decay channel. Feasibility to reconstruct the charmonium states in pp collisions at the ALICE3 is discussed.
One of the most promising ways to obtain a dense ZTA material at relatively low sintering temperatures can be the use of metastable γ+θ-Al2O3 phases as a basis for composite ceramics. The work [1] shows the possibility of obtaining dense composite ceramics of the Al2O3 - YSZ system based on metastable powders γ + θ-Al2O3 at lower sintering temperatures compared to powders of the stable phase α-Al2O3, however, aggregation of the YSZ impurity in the intergranular space of Al2O3 leads to a decrease in the level physical and mechanical characteristics of ceramics due to the pronounced polydispersity of its structural elements. This problem can be solved by varying the conditions for obtaining composite ceramics, in particular, by varying the value of high hydrostatic pressure during the processing of compacts.
As a basis for ceramics, nanopowders of the γ + θ-Al2O3 + n% (ZrO2 + 3mol% Y2O3) (YSZ) system were used, where n = 0, 1, 5, 10, 15 wt.%, annealed in air at a temperature of 1000℃. The powder compacts were processed under high hydrostatic pressure (HHP) conditions ranging from 300 MPa to 700 MPa. The compacts were sintered in air at a temperature of 1550℃. The obtained ceramic composite had a two-phase structure α-Al2O3+n%YSZ.
The study of the surface structure by SEM showed the distribution of YSZ grains in ceramics depending on the treatment of compacts with HHP. At pressures of 300–500 MPa, YSZ grains are concentrated in the intergranular space of α-Al2O3, and at 600–700 MPa, YSZ grains are distributed over the entire volume of the ceramic matrix. In the first case, the structure of the ZTA composite corresponds to an aggregate-strengthened structure, and in the second case, to a dispersion-strengthened structure.
X-ray diffraction analysis and SEM revealed that the process of primary recrystallization and normal growth of α-Al2O3 grains occurs during sintering of compacts, which were processed under HHP conditions at 300-500 MPa. In compacts processed at 600-700 MPa, the process of secondary recrystallization occurs, which leads to a bimodal size distribution of α-Al2O3 grains.
The study of physical and mechanical characteristics showed that the maximum values of physical and mechanical characteristics are achieved in ceramic compositions Al2O3 + 10% YSZ (ρ = 4.1 g/cm3, Hv = 20.16 GPa, σ = 338 MPa) and Al2O3 + 15% YSZ (ρ = 4.09 g/cm3, Hv = 18.5 GPa, σ = 396 MPa) based on metastable θ + γ-Al2O3 powder annealed at 1000°C and treated with high hydrostatic pressure at 700 MPa.
Circle fit routines are used in helix reconstruction for tracking and in ring reconstruction for particle ID. While accurate fits can be achieved with iterative fits, often resolution can be relaxed in favor of speed. We present and compare two flash-algorithms in terms of resolution, CPU speed and mathematical advantage (linearity). The second algorithm is new internationally.
Relativistic heavy ion collisions at a few GeV energy region provide a valuable insight for the properties of strongly interacting matter at high baryon densities. Studying the yields of various particle species produced in the reaction as well as their collectivity may shed light on the Equation of State of the matter created for the brief moments during the collision. We discuss the methods for the particle identification based on the Time-Of-Flight data from the BM@N experimental facility. We also present the first results for the identification of charged hadrons for the recent physical run on the BM@N experiment with Xe beam and CsI target at the beam energy of 3.8A GeV.
A new (improved) model of inflation and primordial black hole (PBH) formation is proposed by combining the Starobinsky model of inflation, Appleby–Battye–Starobinsky (ABS) model of dark energy, and a quantum correction in the modified F(R) gravity. The energy scale parameter in the ABS model is taken to be close to the inflationary scale, in order to describe double inflation instead of dark energy. The quantum correction is given by the term quartic in the spacetime scalar curvature R with a negative coefficient (-δ) in the F(R) function. It is demonstrated that very good agreement (within 1σ) with current measurements of the cosmic microwave background (CMB) radiation can be achieved by choosing the proper value of δ, thus solving the problem of low values of the tilt of CMB scalar perturbations in the earlier proposed ABS model. A large (by a factor of 10^{7} against CMB) enhancement in the power spectrum of scalar perturbations is achieved by fine tuning the parameters of the model. It is found by numerical analysis that it can lead to formation of asteroid-size PBHs with masses up to 10^{20} g, which may form dark matter in the current universe.
Annotation. Metal oxide catalysts (MOCs) for the growth of carbon nanotubes with the general composition Fe2Co/CaCO3 were synthesized using the polymerized complex precursor (PCP) method using chelating agents. It has been established that metal oxide catalysts synthesized by the method of polymerized complex precursors are an order of magnitude more effective than MOCs synthesized by the sol–gel technology; the performance of MOCs obtained using two ligands is significantly higher than the performance of monoligand samples. As a result of the study, it was revealed that the use, in addition to carbohydrates, of a wide range of chelating agents of various natures (polyalcohols, hydroxy acids , amino acids, etc.) in the synthesis of metal oxide catalysts for the growth of CNTs using the method of polymerized complex precursors is advisable and makes it possible to influence the stage of preorganization of the structure of the metal oxide precursor growth catalysts, specific productivity of MOCs and qualitative composition of carbon products.
Introduction. The main factors influencing the synthesis of CNTs by CVD are: the nature of the carbon precursor , the catalyst and the catalyst support. The use of the PCP method in the synthesis of MOСs, the use of chelating agents of different structures, makes it possible to obtain preorganized 3d - structures of the CNT growth catalyst with a hierarchical distribution of pore length and diameter. In this case, we are talking about catalysts with high porosity, a maximally developed surface of the support and ions of active metals evenly distributed on it. All other things being equal, the development of such technologies helps to increase the efficiency and selectivity of metal oxide catalysts for the growth of multi-walled carbon nanotubes (MWCNTs) for the CCVD process and is an urgent task.
Results and discussion . Metal oxide catalysts of general composition Fe2 Co / CaCO3 with molar ratio Fe, Co / CaCO3 equal to 0.12 : 1 were obtained by the PСP method according to the previously described method [1 ]. The following chelating agents were used: sucrose, fructose, glucose, ethylene glycol, diethylene glycol , glycerin, 1,2 - propylene glycol , 1,4 - butylene glycol , polyethylene glycol , polyvinyl alcohol, citric acid, glycine, pentaerythritol. MOСs – PCPs were also obtained using two chelating agents, one of which is citric acid. To compare the efficiency of the MOС – PCP sol – gel catalysts, a catalyst for the growth of CNTs of the general composition Fe2 Co / CaCO3 with a molar ratio of Fe, Co / CaCO3 equal to 0.12:1 was synthesized.
CVD synthesis of MWCNTs was carried out in a tubular reactor at T = 800 ºС (carrier gas – Ar, 60 cm 3/min; carbon precursor gas – commercial propane-butane mixture, 30 cm3/min) according to the previously described method [2].
Analysis of the data allows us to conclude that metal oxide catalysts with a lower bulk density (ρn) are more effective compared to metal oxide catalysts with a higher ρn. It was revealed that MOСs synthesized by the PСP method have a lower ρn compared to MOСs synthesized by the sol–gel method, and the use of a second chelating agent leads to the production of MOСs with low ρn, which increases the specific yield of CNTs. Thus, we can conclude that the synthesis of MOС - PCP using two chelating agents simultaneously allows one to vary the physical parameters of precatalysts - bulk density, porosity, dispersity, specific surface area - over a wide range. This approach will make it possible to obtain MWCNTs with specified morphological parameters.
The work was supported by the Ministry of Science and Higher Education of the Russian Federation, budget topic “Carbon nanoparticles with a given morphology: synthesis, structure and physicochemical properties, FRES- 2023-0006”.
https://docs.google.com/document/d/1hACqJpFey1oxryN7u2yeZP-hPxTL7TzL/edit?usp=sharing&ouid=117450093534487682532&rtpof=true&sd=true
We develop the method to obtain approximations to the solutions of differential equations with slowly varying coefficients. We demonstrate this method applying it to the linear partial differential equation of the first order and to the time-dependent Schrodinger equation in one dimension. Using the approximation to the solution of the Schrodinger equation, it is possible to calculate the partition function in the form of a perturbative expansion. In this expansion, the inverse typical scale of potential energy variation plays the role of the small parameter. To demonstrate that our method is suitable for obtaining the arbitrary order of the perturbative expansion, we find for the first time the statistical mechanic partition function up to the eighth order. Our method turns out to be applicable to the problem of the signal propagation described by the nonlinear Schrodinger equation with the additive Gaussian noise. We consider a fiber channel with large signal-to-noise ratio and small second dispersion. We also take into account the receiver which does not distinguish high-frequency harmonics of the propagating signal. For such model we obtain the expression for the output signal up to the first order in the small dimensionless parameter of the dispersion.
Future linear ${e^-}{e^+}$ colliders with an energy of $\sqrt{s}\geq 500$ GeV are the best options for searching and studying $Z'$ due to the high sensitivity of the process ${e^-}{e^+}\rightarrow{f}{\bar{f}}$ to the effects of $Z'$ at high energies, and especially if there is a possibility of polarization of $e^{-}$ and $e^{+}$ of the beams.
The current limits on the mass of $Z'$ obtained from experiments on LHC correspond to the mass scale of $m_{Z'}\sim 5$ TeV, which significantly exceeds the planned energy of future ${e^-}{e^+}$ accelerators. Therefore, it is unlikely that accelerators are able to perform precision measurements of $Z'$ characteristics. Most likely, it will be possible to investigate only indirect (virtual) effects of $Z'$ caused by $\gamma-Z-Z'$ interference, which will manifest themselves as statistically distinguishable deviations of the observed from their behavior predicted by Standart Model (SM). If deviations of the observed from the behavior of the predicted SM are not experimentally detected at a given level of statistical significance, then experimental information will be presented in the form of restrictions on the characteristics of $Z'$.
An important and current task is to develop a strategy for obtaining constraints with greater accuracy, not using an increase in luminosity or collider energy, but using various optimal conditions and observables.
Stopping power of charged particle with an energy of several MeV and a charge variaty from one proton charge to several tens leads to failures in microelectronic devices designed for rapid storage and storage of information. For example, we are talking about failures, leading to the recharging of an memory element containing one or more transistors. The path length of ions with an energy of about MeV exceeds the size of semiconductor elements in modern microelectronic circuits by many orders of magnitude, reaching 10-100 micron. At the same time, the ions themselves can be obtained by nuclear reactions occurring during the movement of fast neutrons, the scales of the path length of which will noticeably exceed the path length of the ions. It is shown that for the needs of Monte Carlo programs, a promising model is one that allows converting optical databases of the dependence of the complex electrical permeability of a material into databases of the dependence of speed losses of a moving ion. The capabilities of the selected model are tested on broadening gamma lines.
The report is devoted to the development and implementation of a monitoring system for the stand of amplifiers of the harmonic station of the second type - HF2. The monitoring system presented in this report has been developed to ensure continuous monitoring and control of the operation of the bench amplifiers. It includes sensors, software with a warning system about possible failures or anomalies in the operation of amplifiers. This system allows bench operators to reliably monitor the performance and condition of amplifiers, reducing the risk of accidents and ensuring uninterrupted operation of the complex. In the future, it is planned to expand this software to complete control of the state of all amplifying equipment of the harmonic stations of the NICA collider.
The High Granular Neutron Time-of-Flight Detector (HGND) at the BM@N experiment will be used for measurement of neutrons produced in nucleus-nucleus collisions. For the first time, the prototype of the HGND was used in Xe+CsI at 3.0 and 3.8 AGeV run at the BM@N. The multilayer structure (absorber/scintillator) of the detector makes it possible to identify and measure the energies of neutrons produced in nucleus-nucleus collisions. The online real-time monitoring system recently developed and used for the HGND prototype is discussed. Additionally, the preliminary results of the HGND prototype data analysis are presented.
Global hyperon polarization is an important observable for studying the properties of the strongly interacting matter produced in relativistic heavy ion collisions. It is emerging due to the presence of initial angular momentum in non-central heavy-ion collisions and is growing with decreasing energy. Detailed study of global hyperon polarization at NICA energies is an important goal of the MPD experiment. In this work we applying the invariant mass fit method for global polarization of lambda hyperons measurements at the MPD experiment.
Laser confocal microscopy technique (60ps lazer pulse excitation at 445nm) and a Time Correlated Single Photon Counting (TCSPC) technique have been used to study the photoluminescence (PL) in 152 MeV Xe ion irradiated MgAl2O4 single crystals. It was shown that radiation defects produced by swift xenon ions give rise to broad luminescence band positioned in the 470-800 nm wavelength range. The measurements of the PL decay curves have evidenced that lifetime of defect-related PL signal gradually increases from 6 to 10 ns in 500-620 nm spectral range and decreases with ion fluence increasing. The decrease of the luminescence intensity observed after fluences ~1013 cm-2 is attributed to overlapping of individual ion track core regions.
PXI-compatible card combining amplifier and preamplifier for proportional gas counters is presented. This PXI-compatible amplifier/preamplifier is developed for purpose of usage with proportional gas counter sensitive to 14.4 keV and PXI-based Mössbauer spectrometers developed on Palacký University in Olomouc. The card is based on Amptek A225 and Amptek A206 integrated circuits. It allows miniaturization of the spectrometric system, as the amplifier and preamplifier together are in form of one PXI card and thus built in the compact PXI-chassis. There is also no need for the additional power supply, as the developed card is powered by PXI connector from the backpane of PXI chassis. This study will deal with comparison of PXI-compatible amplifier/preamplifier board, amplifier/preamplifier board using same components but in form of stand-alone box and powered by lab power supply and other commercially available amplifiers and preamplifiers in the focus on the signal-to-noise ratio, MCA spectrum and quality and effect of Mössbauer spectrum.
F-type ATP synthase is a large protein complex that synthesizes ATP from ADP and phosphate. It plays a key role in the bioenergetics of any organism. There are three classes of F-type ATP synthase: bacterial, chloroplast, and mitochondrial. Despite significant structural similarities, there are also significant differences between different ATP synthases. Specifically, mitochondrial ATP synthases function as dimers or higher-order oligomers, while chloroplast ATP synthases typically exist as monomers, except for a small ~15% oligomeric fraction.
We have isolated and purified ATP synthase from spinach chloroplasts and investigated its in vitro dimerization process. Structural data obtained using SAXS indicate the dimerization of ATP synthase depending on the ionic strength of the solution. The model that best describes the SAXS data is an I-shape dimer with contacts through the delta subunit. The possible physiological role of chloroplast ATP synthase dimerization is discussed.
We acknowledge the support from the Russian Science Foundation (RSF) Project 22-74-00044.
The project “Siberian Ring Photon Source” (SKIF) is under development. This source of 4+ generation synchrotron radiation will allow for research in various fields of science. SKIF project consists of a synchrotron, a storage ring and a linear accelerator. The linear accelerator is designed for an energy of 200 MeV. In the ring of the storage ring, electron beams gain the energy of 3 GeV necessary for the operation of the synchrotron. The linear accelerator of the SKIF project consists of five regular accelerating structures, a pre-accelerator-buncher, an electron source, a magnetic system, as well as a waveguide microwave path necessary to deliver power (50 MW) from the klystron to the accelerating structures. The operating frequency of the klystron is 2.856 GHz. This article describes the operation, measurements and adjustment of waveguide path elements from the first klystron, which is currently operating in conjunction with the initial part of the accelerator at the BINP SB RAS.
Molecular electronics may provide novel functionalities out of the scope of the traditional silicon-based electronics. This work is aimed at a study of a charge transport in a benzene molecule that is a representative member of a broad class of cyclic molecules. Due to many pathways for a charge propagation, quantum interference effects determine peculiar transport properties in these molecules, thus giving rise to new design principles in molecular electronics. At the same time, because the microelectronic molecular device is an opened quantum system, coupling of the molecule to its environment switches on several dissipation mechanisms and processes, which is expected to strongly influence the charge transport. To study this problem, the dissipative transport is described by the Lindblad master equation for the density matrix of the molecule coupled to a Markovian bath environment. The model of “molecule + bath” is represented in term of interacting qubits. Numerical solutions of the Lindblad master equation in qubit representation are obtained with the use of open-source solver based on matrix product operators (MPO) representation and called lindbladmpo (Qiskit Community GitHub (2022)).
Numerical solutions for charge transport characteristics are analyzed and interpreted. It is shown that interference effects may be weakened` due to dissipative processes, but still they survive if the coupling of the molecule to the bath environment is not too strong.
We consider the statistical mechanics and thermodynamics of a rotating ideal gas of classical continuous helicity particles travelling in three-dimensional Minkowski space. By constructing a phase-space and determining an invariant measure on it, we obtain a one-particle distribution function for the system with constant temperature and angular velocity. We show that macroscopic rotation causes an anisotropy of momenta distribution. This indicates the presence of chiral effects. We also discover partial non-rotation of gas meaning that only one direction of two-dimensional rotation takes place for such gas. Thermodynamics analysis has shown non-monotonous dependence of angular momentum on angular velocity. Phase transition was discovered with small values of angular velocity.
The accelerator technology development requires more and more accuracy improvement of both the manufacture of magnetic elements and their positioning during the accelerator installation. To control the quality of the created magnetic elements, there are various methods of magnetic measurements. Most of the actively used methods involve the use of special precision stands, and therefore magnetic elements are usually measured immediately after production, and then the data obtained are used at the positioning. At the same time, changes in the parameters of magnets associated with mechanical, thermal and other influences during their transportation and installation are not taken into account.
This work is devoted to the study of a magnetic measurement’s alternative method. It is based on the magneto-optical effect of the light polarization plane rotation in optically active media, which makes it possible to visualize the intensity distribution of the magnetic field. The possibility of using a laser tracker (which are now widely used at the positioning of accelerator elements) as a radiation source may allow using this method directly during the positioning of accelerator elements, solving the above problem. The paper describes a method for creating an active optical medium and experiments to observe the visualization of the magnetic field distribution intensities in a constant quadrupole and a constant equally-pole dipole specially made for this research. An algorithm for finding the position of the magnetic axis for these magnetic elements was also developed and a program implementing it was written. For further research, a precision alignment stand was designed and assembled, on which achievable accuracy was tested. Also, for comparison, a permanent dipole magnet was measured by the classical method using Hall sensors.
The results of this study present the prospects of this method and the directions for its further development
The shortage of drinking water is a dilemma faced by our country and the world at large. Whereas approximately 96% of water on earth is rich in salinity, desalination of brackish and seawater is a promising technology for resolving water crisis. However, present desalination technologies are linked with hindrances such as high energy consumption and high maintenance costs. Capacitive deionisation (CDI) has gained popularity as an emerging, energy-efficient, and viable electrochemical desalination technology. CDI consists of two steps: the adsorption and desorption of salt ions from water. When voltage is applied across the cell, ions move to oppositely charged electrodes forming an electrochemical double layer (EDL). When the voltage is reversed the ions are released from the surface of the electrodes, and the electrodes are recovered. The performance of CDI is dependent on the properties of the electrode material such as specific surface area, conductivity, electro-sorption capacity, pore structure, and electrochemical stability. The issue with currently used carbon materials for CDI is that they are derived from non-renewable resources and involve sophisticated and costly synthesis methods. This work proposes the utilization of porous carbon derived from biomass via pyrolysis since it is easily accessible, abundant, and promotes a circular economy. The prepared porous carbon was characterized using Brunauer-Emmet Teller (BET), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Raman spectroscopy, and X-ray diffraction (XRD). The porous carbon from coffee waste grounds exhibits properties required for desalination using CDI technology.
Goal of the work:
Create an axiomatic equivalent to the axiomatics of Haag-Araki and Whiteman, based on the principle of causality for sticky sets.
Relevance of the work:
The new mathematical apparatus proposed in this paper, which includes elements of various interpretations of quantum field theory, nonlinear dynamics and p-addic physics, allows us to solve the problem of constructing a consistent theory for describing compactly generated Cauchy horizons, the vector dominance of the Arnowitt-DeWitt-Mizner energy and others ultrarelativistic effects.
Results:
1. The concept of extended locality of globally hyperbolic sets has been introduced (by introducing a hidden parameter c).
2. A criterion for constructing a network R(O) from a family of sticky sets on a Moran structure is defined.
3. It is proved that such a network is an adhesive network.
4. It is proved that perfectly simple sets with the isotonic property are symplectic.
4. Singular solutions are found in RTG for a geodesic line located outside the light cone
5. It is proved that the polynomial time in the Penner-Kontsevich model is globally hyperbolic
6. The ergodic properties of the temporal ordering operator are studied in the framework of the method of intervals of Markov mappings.
7. The induced integration procedure has been improved using the methods of algebraic field theory /
8. The traceless momentum tensor of matter energy 〖T^*〗_(ωλ ́ ̀ )
9. The notion of non-continuability is generalized to pseudoholomorphic curves.
10. A spectral approach has been introduced to consider operators of the form T_p
11. A connection has been found between superselection rules and the choice of superlight-speed alternatives
12. A new method for localizing eventually periodic points based on epsilon cycles has been created.
We consider the $\alpha_s$ order of the Drell-Yan process with Z and W boson production, where one hadron is polarized. Our work focuses on calculating the helicity structure functions, which determine the angular distribution of leptons in the pair rest frame. The calculation is performed using the collinear approximation.
The Resource Sharing Centre «The Siberian Circular Photon Source» ("SKIF") is a fourth-generation synchrotron radiation (SR) source currently under construction in Novosibirsk. "SKIF" will require unprecedented orbit stability because the effect of seismic noise might become a relevant source of brighness loss, several studies have been conducted to characterise the actual ground motion in the area of the construction site of the "SKIF". This work summarises the observations made on the "SKIF" area and uses this data to estimates of the impact of vibrations on the closed orbit at the radiation output points.
The multi cavities S-band klystron with an output pulse power of 50 MW is developed at Budker Institute of Nuclear Physics SB RAS. Such klystrons are needed for many fundamental scientific projects: SKIF, Super C-tau factory etc.
The input cavity is one of the most important cavity in the klystron. Its quality influences on the gain and efficiency of the klystron. The input cavity should have a sufficient list of the requirements: a vacuum coaxial line coupling; frequency matched with the beam; ability to adjust frequency and coupling after manufacture; work stability without self-excitation etc.
This work describes the parameters of the input cavity, its design, as well as measurements without and with beam. It is experimentally shown that the input cavity is almost completely matched with the microwave power coaxial line coupling with the operating current of the beam. The conditions for the appearance and decrease of multipactor discharge are described.
The Spin Physics Detector is an experiment at NICA designed to study the spin structure of the proton and deuteron and the other spin-related phenomena using polarized beams.The collision energy is up to 27 GeV and the luminosity is up to 10^32 cm^−2 s^−1 in pp mode.
Two scintillator-based detectors, Beam-Beam Counters (BBC), will be installed upstream and downstream the interaction point and will serve as a tool for beam diagnostics including local polarimetry. The BBCs will be designed as high granularity scintillation detectors.
In this talk, we present the tests of the BBC prototype based on the tiles with the green wavelength shifter (WLS) and SensL SiPM readout. The prototype was tested with 1x1 mm^2 and 3x3 mm^2 SensL SiPM with the FERS-5200 front-end readout system. The amplitude and timing resolutions for different tiles using cosmic rays are obtained.
The multilayer neutron detector for the SCAN-3 spectrometer at the Nuclotron accelerator has been developed. Neutron detector consists of a set of 3x2 modules covering total area of 80*54 cm2. Each module represent 4-layer scintillator detector with dual light readout from scintillator plates by PMTs. Set of modules has been tested by the cosmic rays. The results of the research of individual multilayer neutron modules are presented here.
The Spin Physics Detector (SPD) at JINR NICA complex is currently under construction [1]. The straw tracker detector is aimed to reconstruct the primary and secondary particle tracks and to determine their momenta. For the stage of the SPD active operation it is necessary to develop
fast data processing algorithms for online data collection, event selection and primary vertices reconstruction. In the present work we simulate the response of SPD tracker in the trigger-free regime of data processing.
Using the GEANT4 software package [2] we have modeled a geometry of the SPD straw tracker, its sensitive volumes and their response. We store the collections of hits containing the characteristics of particle energy loss points. We obtained the time distributions of the simulated hits in sensitive volumes, taking into account the drift time of the electron avalanche [1], and find a significant overlap of the response times of straw tubes for particles produced in different bunch crossings from the same time slice. This fact points out to the problem of signal decoding for event reconstruction when collecting data in a real experiment.
We develop the algorithm for primary vertices reconstruction, based on the reconstructed particle tracks from the hits data. This one to be a prototype for the software of event reconstruction at the stage of online data selection.
Bibliography
[1] The SPD сollaboration, Teсhniсal Design Report of the Spin Physiсs Deteсtor// spd.jinr.ru. URL: http://spd.jinr.ru/wp-content/uploads/2023/03/TechnicalDesignReport_SPD2023.pdf (дата обращения: 06.06.2023).
[2] Программный пакет GEANT4 // geant.web.сern.сh - 2020 - URL:
https://geant4.web.сern.сh/download/11.1.1.html
A prototype of a track scintillation detector has been developed. The detector is necessary to obtain two-dimensional spatial information about the processes under study. The detector is based on a monolithic cubic scintillator, viewed from different sides by a highly sensitive Sensls SiPM matrix. The report describes a technique for obtaining an image of a track of a passing particle through a scintillator.
The measurement of transverse single asymmetries (AN) contributes to the better understanding of the nucleon structure. Significant AN values in forward rapidities were obtained in previous experiments, contrary to the pQCD expectations. Different mechanisms to explain such sizeable asymmetries have been proposed and are still under discussion. An analysis based on Monte Carlo simulations of the yield distribution as function of xF and pT and the estimated accuracy level for the transverse single-spin asymmetry measurements, is provided for inclusive pi0 and eta mesons collected in the ECAL - endcaps of the Spin Physics Detector at NICA, with pp collisions up to sqrt(s) = 27 GeV. The eta/pi0 cross-section ratio is also evaluated.
The current consensus cosmological model, LCDM, is for the most part in good agreement with observations. However, not all is well: as our measurements of both early and modern Universe are becoming more and more precise, a gap opens between different indirect measurements of the Hubble constant, i.e. the rate at which the Universe is expanding today. Many attempts to cross this gap have been made, but none have resoundingly solved the H0 problem. The presentation outlines the current state of the problem and showcases the difficulties in solving it with an extended theoretical cosmological model (the phantom-crossing dark energy) and the necessity of carefully choosing how to combine ovservational datasets when comparing between models, as the most significant case of the H0 tension arises from a discordance in type Ia supernova magnitude calibrations using a local and an inverse distance ladder.
Within the framework of quantum electrodynamics, the interaction of particles can be described using invariant perturbation theory. Higher orders of perturbation theory are expressed in terms of loop integrals. The modern approach to calculating loop integrals is to use the Integration-By-Parts method. This method allows you to express loop integrals through the so-called master integrals. One of the methods for calculating master integrals integrals is to construct systems of differential or difference equations. The method of differential equations is used for integrals with several scale parameters, the method of dimensional recurrence relations for single-scale integrals. In this work we show how to combine these two methods and calculate two-loop massive QED master integrals for the process $e^{+}e^{-}\rightarrow2\gamma$. Expressions for master integrals is obtained in the high-energy approximation.
Enhancing object recognition by optimizing sharpness
Deeva Olga(a), Inna Kolesnikova(b), Oksana Streltsova(b), Marko Ćosić(c)
(a) National Research Nuclear University MEPhI
(b) Joint Institute for Nuclear Research, Laboratory of Radiation Biology, Dubna, Str. Joliot-Curie 6, Russia
(c) Institute of Nuclear Sciences Vinča, National Institute of Republic of Serbia, University of Belgrade, Belgrade, Serbia
The task of recognizing objects in an image is relevant in many spheres of human activity. Since the image can be distorted by noise, blurred or be poorly-lit, it is necessary to use preprocessing for high-quality recognition of objects. In our software the sharpness, which was defined as a maximazed gradient, of the monochromatic image was found depending on the percentage of rgb channels when added to a gray image. According to the data, 3d graphs of the sharpness dependence on the channels were constructed. The obtained result can be used to sharpen any images. The initial idea of this algorithm was to sharpen the images of hippocampus (that consist of neuron cells, vessels and sometimes artefacts), so that these changed images could be used as a data for further studies. Such preprocessing could be a great part of a future contemporary tool for pathomorphologists as well as for scientists in this branch.
Search and study of multiquark XYZ states is one of the urgent tasks of modern high energy physics. Calculations obtained using Lattice QCD cannot fully describe spectrum of that states and predict parameters currently unopened states. Studying the properties of exotic hadrons can bring us to a better understanding of the strong interaction. In this report, results of the amplitude analysis of $B^{0} \to J/\psi K \pi$, $B_{s} \to J/\psi K K$ decays at the ATLAS experiment at the LHC are presented. The analysis is based on a sample of $pp$ collision data at the center of mass energies $\sqrt{s}$ = 13 TeV corresponding to integrated luminosity of 139 $fb^{-1}$. Contributions from the exotic states $Z_{c}^{\pm}(4200)$, $Z_{c}^{\pm}(4430)$, $Z_{c}^{\pm}(3900)$, $Z_{cs}^{\pm}(4000)$, $Z_{cs}^{\pm}(4220)$ to the above mentioned decays are observed with a total significance above 10$\sigma$. The report also contains study of various spin-parity options of $Z_{c}^{\pm}(4200)$ state.
The NA64 experiment at the CERN SPS is designed primarily to search for dark photons in events with missing energy. Some other similar processes that have the missing energy signature can also be searched for the Lepton flavor violation (LFV), for example $e \rightarrow \tau$, $e \rightarrow \mu$, $\mu \rightarrow \tau$ and $\mu \rightarrow e$ conversions. The NA64 is capable for search lepton conversion in the inclusive scatterings of electrons or muons on nuclei $l + (A,Z) \rightarrow l'+ X$. Preliminary estimations of the NA64 sensitivity in the electron and muon beam will be performed. The probability of observing a process in an experiment based on current statistics will also be discussed.
When analyzing the rare Higgs-top channel, there is a problem of isolating this channel from the background. The separation problem can be solved using machine learning. A neural network is one of the most modern methods of Machine Learning. But the result of such an analysis highly depends on the set of input kinematic variables, the network architecture and other network hyperparameters. Obviously, manually selecting hyperparameters is not time-optimal and does not guarantee good results. Using an evolutionary algorithm to optimize a neural network significantly improves the efficiency of the network.
We study Z-boson production at the LHC energies within framework of the parton Reggeization approach of high-energy QCD [1,2]. Oppositely the previous calculation [3], based on LO approximation with the partonic process Q + Q¯ → Z, we take into account NLO contribution from the partonic process Q + R → q + Z, where R is the Reggeized gluon and Q is the Reggeized quark. The good agreement with experimental data as for Z-boson pT-spectra as for total cross section was found. The lepton angular coefficients in Z-boson events are studied by the same way, in the LO and in the NLO of the Parton Reggeization approach. The last one is performed in the high-energy factorization in the first time.
[1] M. Nefedov and V. Saleev, Off-shell initial state effects, gauge invariance and angular distributions in the
Drell-Yan process, Phys. Lett. B790 (2019), 551-556
[2] M.A. Nefedov, V.A. Saleev and A.V. Shipilova, Dijet azimuthal decorrelations at the LHC in the parton
Reggeization approach, Phys. Rev. D87 (2013) no.9, 094030
[3] M.A. Nefedov and V.A. Saleev. High-Energy Factorization for Drell-Yan process in pp and pp¯ collisions
with new Unintegrated PDFs, Phys. Rev. D102 (2020), 11401
New recombinant vaccines based on globular protein complexes with fused immunogens have shown amazing efficiency against a number of diseases, e.g., influenza, HIV, HCV, Epstein-Barr, etc. The features of such vaccines: multiple antigen representation, assembly of trimeric viral surface proteins on the surface of 24-meric protein apoferritin at the places of its three-fold channels, and a dual function of a bacterial apoferritin which acts as an adjuvant as well as a carrier. However, in the case of apoferritin-RBD recombinant vaccines the studies showed a necessity of additional adjuvants to achieve an immunological effect in preclinical studies, which might be due to the stochiometric hindrance of RBDs which do not form trimers and might cover apoferritin surface making it hidden from antibodies.
We developed a protocol for obtaining a self-assembling 8-meric apoferritin-RBD recombinant protein complex which has a form-factor of a one third of a sphere, which was confirmed by small-angle X-ray scattering and electron microscopy. The 8-meric apoferritin-RBD might be a potential vaccine in which an internal surface of bacterial apoferritin is available for antibodies due to reduced stochiometric hindrance in comparison with 24-meric apoferritin-RBD vaccines.
We acknowledge the support from the Ministry of Science and Higher Education of the Russian Federation (agreement # 075-03-2023-106, project FSMG-2021-0002).
Ferritin is a globular protein complex essential for iron assimilation and storage within the protein shell of apoferritin. Given its unique biochemical properties and globule topology, ferritin has diverse applications, some of which are already realized, while others remain prospective. This work focuses on a potential application of ferritin as a dietary supplement for iron deficiency and anemia prevention. We highlight the potential of ferritin as an iron source and supplement. We show that small-angle scattering studies of ferritin migth enhance in vitro experiments towards understanding molecular mechanism of iron release and uptake. However, a deeper understanding of the molecular mechanisms regulating ferritin levels and iron metabolism is essential to determine the most effective ways to harness ferritin for human health.
This study was supported by Ministry of Science and Higher Education of the Russian Federation, project FSMF-2022-0007 “Development of technology for rational and highly productive use of agro- and bioresources, their efficient processing and obtaining safe and high-quality sources of food and non-food products”.
The unique Dsup protein discovered in the tardigrade Ramazzottius varieornatus has been shown to increase resistance to radiation and oxidative stress in various model organisms, including human cell culture. The hypothesis suggests that Dsup forms a complex with DNA, which reduces damage caused by reactive oxygen species formed during water radiolysis. In order to understand the molecular mechanisms of radioprotection by Dsup protein and to develop applications of this protein, it is crucial to inspect the stability of Dsup to ionizing radiation. We investigated the susceptibility to degradation of Dsup and control bovine serum albumin (BSA) proteins exposed to γ-rays with doses up to 10 kGy. Combined study by small-angle X-ray scattering (SAXS) technique and polyacrylamide gel electrophoresis of proteins (SDS-PAGE) was performed. We demonstrate the Dsup protein is highly stable to the damage by ionizing radiation and, in particular, relatively to the control BSA.
At the present time there is a hypothesis about the key role of amyloid beta peptide in the onset of Alzheimer's disease. It is considered that its interaction with cell membranes causes a disruption of their permeability and integrity, which may trigger further neurodegenerative processes. The experimental study showed that the peptide takes part in the morphological changes of the phospholipid membrane during its transition through the main lipid phase transition temperature. However, this study does not allow us to look into the processes and resulting structures at the atomic level, as a result of which theoretical studies were carried out.
In order to describe the assembly process of phospholipid membranes in the presence of amyloid beta peptides, the interaction of Aβ(25-35) with zwitterionic DPPC phospholipids was simulated using the coarse-grained molecular dynamics method in the GROMACS 2019.3 software package. It was found that at a temperature below the phase transition temperature of the lipid, the system assembled into bicelle-like structures with peptides on the rim, while at a temperature above the phase transition temperature, it assembled into a system of small vesicles with peptides embedded in the lipid bilayer. The results obtained are in good agreement with earlier experimental results and complement the picture of what is happening in phospholipid membranes.
The formation of dust particles into chain structures in a flowing plasma environment is a well-known phenomenon which is inherent for the experimental conditions typical for RF or DC discharge plasma [1]. The structural and dynamical properties of the chains being formed are inextricably linked with the surrounding plasma media. Due to the high complexity of the interdependence between dust and plasma parameters, analytical approaches can hardly be applied to the description of such systems and numerical ones should be incorporated. Numerical calculation of flowing plasma around dust particles which considers self-consistent charging is a very resource intensive task and highly optimized codes should be used. Previously, we have developed the fast GPU-based code, OpenDust [2], for the self- consistent calculation of forces, acting on dust particles, immersed in a plasma-flowing environment and dust particles charges. Here, we incorporate OpenDust to study various structural and dynamical properties of dust particle chain structures simultaneously calculating dust and plasma dynamics. Typical view of a dust particles chain structure during the simulation is presented in the Figure 1.
References
[1]. Kong J. et al. Interaction force in a vertical dust chain inside a glass box //Physical Review E. – 2014. – Т. 90. – №. 1. – С. 013107.
[2]. Kolotinskii D., Timofeev A. OpenDust: A fast GPU-accelerated code for calculation forces, acting on microparticles in a plasma flow //arXiv preprint arXiv:2205.06557. – 2022.
Actinide compounds are among the most challenging objects for ab initio electronic structure modeling due to strong relativistic effects, multi-configuration nature of electronic states, and high density of levels in their spectra.
We present recently developed tools for high-precision modeling of such systems: the EXP-T program package [1] implementing new variants of the relativistic coupled-cluster method in the Fock space, the LIBGRPP library for calculating molecular integrals with generalized relativistic pseudopotentials [2], and new approaches to calculating off-diagonal matrix elements of property operators, including those defining for intensities of electronic transitions and hyperfine effects.
Using the theoretical developments and software tools, low-lying electronic states of AcF, ThO, UO2 molecules were simulated, and information about the structure and spectra of these molecules was obtained. Term energies of the ThO molecule were obtained with errors significantly smaller than the vibrational quanta, thus allowing one to perform an unambigous vibrational assignment of its rovibronic spectra [3]. A comprehensive quantitative model of the vibronic spectrum of the AcF molecule was constructed [4], opening up possibilities for planning experiments on laser resonance ionization spectroscopy of this molecule.
The developed tools were also applied to simulate electronic spectra of cerium (Ce3+) and thorium (Th3+) impurity ions embedded into the xenotime (yttrium orthophosphate YPO4) matrix. For this purpose coupled cluster calculations were combined with the the compound-tunable embedding potential (CTEP) approach proposed recently [5] for ab initio calculations of local properties in ionic crystals via constructing minimal cluster models with broken covalent bonds. Pilot calculations were shown to be able to reproduce the energies of transitions localized on the Ce3+ impurity ion with the error not exceeding 0.3 eV.
The work of A.V.O., A.Z., Yu.V.L., N.S.M. and A.V.T. at NRC "Kurchatov Institute" – PNPI on the development of software tools and further pilot applications to ThO, AcF and xenotime was supported by the Russian Science Foundation under grant no. 20-13-00225, https://rscf.ru/project/23-13-45028/.
[1] A. V. Oleynichenko, A. Zaitsevskii, E. Eliav. Commun. Comput. Inf. Sci., 1331, 375 (2020).
[2] A. V. Oleynichenko, A. Zaitsevskii, N. S. Mosyagin, A. N. Petrov, E. Eliav, A. V. Titov. Symmetry, 15, 197 (2023).
[3] A. Zaitsevskii, A. V. Oleynichenko, E. Eliav. Mol. Phys., e2236246 (2023).
[4] L. V. Skripnikov, A. V. Oleynichenko, A. Zaitsevskii, N. S. Mosyagin, M. Athanasakis-Kaklamanakis, M. Au, G. Neyens. J. Chem. Phys., 159, 124301 (2023).
[5] Yu. V. Lomachuk, D. A. Maltsev, N. S. Mosyagin, L. V. Skripnikov, R. V. Bogdanov, A. V. Titov. Phys. Chem. Chem. Phys., 22, 17922 (2020).
The work is dedicated to development of a new MATLAB based tool for calculation of characteristics of MEMS devices, particularly Capacitive Micromachined Ultrasound Transducers (CMUT).
Main features of the created program is ability to calculate a frequency response of an array of circular cells and its radiation pattern in a transmitter mode, without use of finite or boundary elements. It also provides a user with information about collapse voltage (maximum allowed DC voltage to apply), eigenfrequencies and eigenmodes, and displacement profile under applied voltage (DC+AC). It provides a simple interface, high calculation speed and sufficient accuracy in comparison with conventional finite elements method (FEM). Thus, it does not require presense of sophisticated software for FEM.
The presentation is going to include explanation of the algorithm's principles and comparison of its results with other numerical methods.
Formation of drops on impurities (condensation cores) is omnipresent in nature and can play a desirable or undesirable role in technology. The transition from vapor state to liquid state starts with the formation of a metastable thin film covering the condensation core, after which the system has to overcome an energy barrier (a critical droplet state) to steadily transform into the liquid state. Both the metastable and critical droplets are small enough to consider the number of molecules in the system as unlimited. However, the widespread approach to studying this microscopic process is molecular modeling within a closed container with a fixed number of molecules. Thus, the question arises, how does the confinement (i.e. limited number of molecules) affect obtained solutions? Besides understanding results of modeling, these effects could be used in practice for stabilizing and preventing nucleation in small containers (see [1–3] for homogeneous nucleation study).
We address this issue firstly on a macroscopic thermodynamic level of description, and then confirm the results within two versions of classical density functional theory: the square-gradient approximation with the Carnahan–Starling equation of state for hard spheres [4] and the random-phase approximation with the fundamental measure theory [5,6].
We consider formation of a droplet around a spherical solid particle immersed in vapor and investigate the number and stability of equilibrium solutions in the canonical ensemble in comparison to the grand canonical ensemble. Depending on the system’s parameters, two modes exist in the canonical ensemble: the first one with an only solution, and the second one with three solutions; the presence of the third solution is due to confinement.
In the case of a small total number of molecules, a solution breaking the spherical symmetry is observed. This sessile droplet, being stable in the canonical ensemble, corresponds to the critical droplet in the grand canonical ensemble. This notion paves the way to obtaining critical solutions as a result of minimization procedure in the canonical ensemble, instead of finding saddle points in the grand canonical ensemble. Thus, in some region of parameters, a transition to the liquid state via a non-spherical critical state is more “cost-effective” in terms of the energy barrier.
References
1. Ø. Wilhelmsen, D. Bedeaux, S. Kjelstrup, D. Reguera, J. Chem. Phys. 140, 024704 (2014).
2. Ø. Wilhelmsen, D. Bedeaux, S. Kjelstrup, D. Reguera, J. Chem. Phys. 141, 071103 (2014).
3. Ø. Wilhelmsen, D. Reguera, J. Chem. Phys. 142, 064703 (2015).
4. R. Evans R., Advances in Physics, 28, 143–200 (1979).
5. R. Roth, R. Evans, A. Lang, G. Kahl, J. Phys.: Condens. Matter 14, 12063–12078 (2002).
6. L. Gosteva, A. Shchekin, Physics of Particles and Nuclei Letters, 20 (5), 1084–1087 (2023).
This paper deals with correlation functions in a six-dimensional planar fishnet model. Correspondences between spectra of different models are shown, and calculations for correlators in different regimes of the coupling constant are performed.
The experimentally observed significant polarization of Λ and anti-Λ particles in heavy-ion collisions leads to speculations that rapidly rotating swirls of nuclear matter are created. We use the PHSD transport model to simulate the Au+Au collisions at the NICA energies and perform the fluidization procedure determining density, temperature, and velocity, and then calculating vorticity and hydrodynamic helicity fields. The velocity field looks dominantly as the Hubble-like profiles expanding in transverse and longitudinal directions (approximate cylindrical symmetry). The vorticity field is like a small perturbation on the top of the longitudinal and transverse flows. Then we investigate freeze-out conditions for different particle species and find the source of polarization. Finally, we calculate the global polarization of (anti-)hyperons on a dynamic freeze-out surface and compare the results with the experimental data.
In quantum field theory an important role is played by various hypergeometric functions. Of particular interest is their close relationship with Feynman loop integrals. The latter are used to calculate higher corrections in perturbation theory to the measurable physical processes. Which becomes especially important now that the accuracy of measurements is increasing. There are many ways to solve Feynman loop integrals using hypergeometric functions. These solutions have the common property that the indices of the hypergeometric function linearly depends on a small parameter. And for practical calculations, it is necessary to obtain a Laurent expansion in this small parameter. In this case, it is desirable that the expansion elements be expressed in terms of well-defined functions that can be calculated with arbitrary precision.
In this work we study the expansion of various hypergeometric functions in a Laurent series with respect to a small parameter in terms of multiple-polylogarithms. For this purpose, we mainly use the differential equation method and the Lee algorithm. Specifically, we will be interested in the generalized hypergeometric functions, the Appell and Lauricella functions. In these calculations, a particularly important role is played by the replacement of the variable: rational in one direction and irrational in the other. This issue is discussed with special attention.
We probe the five-dimensional Kerr-AdS space time by pulsating strings. First we find particular pulsating string solutions and then semi-classically quantize the theory. For the string with large values of energy, we use the Bohr-Sommerfeld analysis to find the energy of the string as a function of a large quantum number. We also consider the case of constructing a quantum metric tensor.
The $\Sigma^{0}$ hyperon is reconstructed via its electromagnetic decay into $\Lambda + \gamma$ due to the unique ability of ALICE to register low-energy photons.
Different methods of background subtraction for the measurement of the yield of $\Sigma^{0}$ hyperon invariant are investigated. It is done by
the approximation of the background shape by the
polynomial function and the application of the mixed background technique with Lambda hyperon taken from one event and photon from another. For the mixed background, the counting regions of the signal events were varied. A comparison of the methods has been conducted.
The $\Sigma^{0}$ hyperon yields are presented in different transverse momentum regions with corresponding systematic uncertainties.
The invariant cross sections of $\pi^0$ and $\eta$ mesons provide strong constrains to the nuclear structure of the colliding particles, while the spectra of direct photons in heavy-ion collisions carry undistorted information about the thermodynamic evolution of the quark-gluon plasma (QGP). In addition, Hanbury Brown and Twiss (HBT) correlation of direct photons can shed light on the time-space properties of QGP at its earliest stages. At the ALICE experiment, photons are reconstructed with the photon conversion method using the tracking system, and are directly detected in the electromagnetic calorimeters. The combination of these methods allows the measurement of direct photons over a wide transverse momentum ($p_{\mathrm{T}}$) range, covering both thermal direct photons and prompt direct photons. Light neutral mesons, in their turn, are measured via the invariant mass of their decay products. Moreover, the merged cluster approach in calorimeters provides the ability to measure $\pi^0$ mesons at unprecedentedly large $p_{\mathrm{T}}$ (up to 200 GeV/$c$). In this report, recent results of the ALICE experiment on light neutral meson in pp collisions at $\sqrt{s} = 13$ TeV and direct photon measurements as well as the HBT correlation of direct photons in Pb$-$Pb collisions at $\sqrt{s_{NN}} = 5.02$ TeV are presented.
The decay of the charged kaon K+→π+π-π+γ is currently rather poorly studied. A research (Shapkin et. al, 2019) confirmed the correspondence of the differential branching values with the calculated values based on the chiral perturbation theory, but only for photons with an energy of at least 30 MeV. Currently, the measured value of the branching of this decay is (1.04±0.31)10^-4 under the condition Eγ > 5 MeV. The experimental setup NA62, having superior technical characteristics, allows to obtain many times more decay events and to measure the decay parameters more accurately, as well as over a larger range of photon energies.
Within the framework of this work, a selection of events of the decay K+→π+π-π+γ was developed and carried out. Signal and background decays are modeled using the Monte Carlo method. The differential branching of the decay was measured depending on the photon energy with a step of 1 MeV. There is a good correspondence in the predictions.
As a result, 69068±19 decays of K+→π+π-π+γ were selected and the branching of the process was calculated.
The number of events with high (more than 50 MeV) photon energy was too small for the correct calculation of differential branching. For this purpose, to improve the accuracy of the results, the method of data unfolding was applied using a large number of K+→π+π-π+γ decays generated in advance by the Monte Carlo method.
The data obtained are consistent with the previously obtained value of the process branching, and also complement it with the differential dependence of the branching on the photon energy obtained for the first time in the energy range from 10 to 70 MeV.
A large-scale tracking detector TREK has been constructed at the National Research Nuclear University MEPhI. This detector has been developed for the purpose of investigating cosmic ray muon bundles at large zenith angles. Covering an area of 250 square meters, the detector consists of two planes of multi-wire drift chambers. The main features of this detector is the vertical deployment of detecting planes.
The TREK detector provides practically a continuous area that is 7 times larger and 10 times better in track resolution compared to its counterpart, the DECOR detector. These advancements significantly contribute to addressing the “muon puzzle”. This puzzle pertains to the origin of the observed excess of cosmic ray muons, which begins at energy range of 10 PeV and has been a subject of investigations in experiments like NEVOD-DECOR, IceCube, the Pierre Auger Observatory, and others.
The report presents the results of launching the planes of the TREK detector, the results of testing of drift chambers on the testbench. The estimates of the efficiency and the accuracy of track reconstruction will be discussed.
The K^{+} → π^{0}µ^{+}νγ (K_{µ3γ}) and K^{+}→π^{0}e^{+}νγ (K_{e3γ}) decays are measured with OKA detector at the RF-separated 17.7 GeV/c momentum kaon beam from the U-70 synchrotron. The data obtained corresponds to the value of 2.62 × 10^{10} «live» kaons passing to the decay volume. About 10^{3} K_{µ3γ} and 10^{5} K_{e3γ} events are extracted. The ratios of R_{µ} = Br(K_{µ3γ})/Br(K_{µ3}) and R_{e} = Br(K_{e3γ})/Br(K_{e3}) are found to be (4.45 ± 0.25(stat)) × 10^{−4} and (58.7 ± 1.0(stat) ± 1.5(syst)) × 10^{−4} respectively. The T-odd correlation ξ_{πμγ} (ξ_{πeγ}), which is the mixed product of the momenta of µ^{+}(e^{+}), π^{0}, and γ in the kaon rest frame, is measured. The asymmetry of the distribution in ξ is characterized by the ratio A_{ξ} = (N_{+} + N_{−})/(N_{+} − N_{−}), where N_{+(−)} is the number of events with positive (negative) ξ. The value A_{ξ} = −0.006 ± 0.069(stat) for µ^{+} and (0.1 ± 3.9(stat) ± 1.7(syst)) × 10^{−3} for e^{+} is obtained.
During surgical intervention it is important to know the state of the sutured tissues to prevent postoperative complications. One of the possible ways to determine tissue condition is to measure the level of the oxygen saturation. In this work considered goal was reached by the method of diffuse scattering spectroscopy. The equipment, which was used to perform the measurements, included spectrometer “LESA-01-BIOSPEC”, broadband light source, optical fiber and PC with special software “Uno Momento”. The saturation determining was performed intraoperatively during operations with anastomosis application. When performing esophageal resection saturation was measured not only during open stage of the surgery but also torascopically after the anastomosis formation. Also one of the peculiarity for this organ is the preservation of the saturation level after tissue intersection, while for the stomach and intestine this value decreases significantly after the mobilization of the vessels. Based on the results of this work method of diffuse scattering spectroscopy is suitable for the assessment of tissue state by the measurement of the oxygen saturation level during anastomosis surgeries on the different parts of the gastrointestinal tract.
Studies of new proteorhodopsins from various bacteria have shown that they have both similarities and differences in their functional properties compared to the model rhodopsin - BR. In particular, the group of microbial rhodopsins with the DTG motif in the active center, which includes the proteorhodopsin from Sphingomonas paucimobilis (SpaR), may be of interest [Malyar N., 2020].
In this work, the dependence of SpaR activity on the concentration of divalent ions and pH of the medium was investigated [Okhrimenko, Ivan S., et al., 2023]. For this, the rhodopsin was embedded in liposomes and photocurrents were recorded through a bilayer lipid membrane. It was found that zinc ions, neutral and alkaline pH inhibit the light-induced proton transfer of SpaR. These data suggest that SpaR and similar proteins may form a subclass of the group of proteorhodopsins with a specific motif, the common distinguishing feature of which is a strong sensitivity of proton transport to pH and zinc ions.
The dependence of the protein SpaR's photocycles on pH was also shown. The elongation of the photocycle occurs due to the formation of the O-state, which leads to a parallel decrease in the proton transport activity of the protein [Okhrimenko, Ivan S., et al., 2023].
Thus, studies of the proteorhodopsin SpaR allow for a better understanding of its mechanisms of action and differences in functional properties. This can help in further improving the process of developing and improving optogenetic tools and their effectiveness.
ATP synthase is an essential protein complex integral to the bioenergetics of all living organisms. Located within the membrane, it facilitates the conversion of ADP into ATP using an inorganic phosphate, leveraging the proton concentration gradient across the membrane [1]. The proton flow induces rotation in the membrane domain of ATP synthase (specifically, the rotor c-ring). This rotation triggers conformational shifts in the $F_1$ segment of ATP synthase, catalyzing ATP synthesis.
A critical bioenergetic metric is the ATP/$H^+$ ratio, which represents the number of ATP molecules synthesized for every proton passing through the c-ring. This ratio is influenced by the stoichiometry of the c-ring, specifically the number of $c_1$ monomers constituting the $c_n$-ring, and is generally represented as 3/n. While evidence suggests that the stoichiometry of cn is influenced by the amino acid sequence of $c_1$ [2], several questions remain about the primary determinants of c-ring stoichiometry. The impact of the surrounding protein environment on stoichiometry, for instance, remains elusive. Additionally, for many organisms, the stoichiometry of c-ring is yet to be determined, and current algorithms, such as Alphafold, have been inadequate in predicting it.
In this study, we examined a recombinant c-ring derived from spinach chloroplasts, produced in Escherichia coli cells. The gene was cloned into E.coli TG-1 cells, followed by the isolation and purification of $c_1$ monomers. Utilizing gel electrophoresis and Western blotting, we analyzed the proteins. Our findings confirm the successful expression of the $c_1$ protein from spinach chloroplasts in E.coli cells. We further discuss methodologies for assembling the c ring within E.coli cells.
We acknowledge the support from the Russian Science Foundation (RSF) Project 22-74-00044.
[1] Vlasov, A. V., et al. "Unusual features of the c-ring of $F_1F_o$ ATP synthases." Scientific reports 9.1 (2019): 1-11.
[2] Pogoryelov, Denys, et al. "Engineering rotor ring stoichiometries in the ATP synthase." Proceedings of the National Academy of Sciences 109.25 (2012): E1599-E1608.
Ferritin is a protein complex whose presence is vital in almost all living organisms due to its responsible for storing iron. The protein is essential to iron homeostasis and is involved in a wide range of physiologic and pathologic processes. According to [1], ferritin’s mechanism of self-assembly can be used as part of an effective small molecule delivery system. Therefore, there are a lot of potential application of ferritin in medicine and biotechnology, especially in vaccine production. We have studied some aspects of the process of ferritin’s self-assembly using ColabFold v1.5.2 which is a tool based on Alphafold2. It is an artificial intelligence system that can predict three-dimensional structures of proteins from amino acid sequences with great accuracy [3]. AlphaFold2 has already proven its power to predict the three-dimensional structure of the majority of 200 million proteins [4], and recent research only confirms its importance for science [5,6].
In this work, we performed an analysis of different hybrid oligomers of ferritin and recombinant protein linked to ferritin. We examined ferritin from Helicobacter pylori, which is a globule of 24 identical subunits. Assuming that physical or chemical action could disrupt its structure into oligomers of fewer subunits, we wondered what configurations they could be formed into. Using AlphaFold2, dimers, trimers, and tetramers were obtained that demonstrate significant structural similarity to the arrangement that associations of the corresponding number of subunits have in the native state of the whole globule. Unexpected structures were also obtained - for example, a trimer with cylindrical symmetry. Next, given the potential of ferritin as a small molecule delivery vehicle, we investigated the possibility of assembling hybrid globules from ferritin subunits (Fer) and fusion proteins (FerS) that were constructed by linking a ferritin subunit with a small protein. Using Alphafold2 we obtained all possible variants for hybrid dimers, trimers and tetramers. We then compared their similarity with the corresponding regions in the structure of the native ferritin globule. We obtained structures that show topological similarity to the native ferritin globule for hybrid protein oligomers such as $Fer-FerS_{}$, $(FerS)_{2}$, $(Fer)_{2}$$-FerS_{}$, $Fer_{}$$-(FerS)_{2}$, $(FerS)_{3}$, $(Fer)_{3}$$-FerS_{}$, $Fer_{}$$-(FerS)_{3}$, $(FerS)_{4}$. We were unable to obtain a corresponding structure for the oligomer composed of two original ferritin subunits and two subunits cross-linked with a small protein. The predicted structures differed significantly from the corresponding regions of the native globule.
From this we conclude that there is reason to believe that hybrid globules with attached small molecules could be produced in the future and used for drug delivery and other biomedical and scientific purposes. We will continue to explore oligomers from a larger number of monomers to improve our understanding of the ferritin-based globules self-assembly.
We acknowledge the support from the Russian Science Foundation (RSF) Project 22-74-00044.
References:
1. Sudarev, V., Dolotova, S., Bukhalovich, S., et al. Ferritin self-assembly, structure, function, and biotechnological applications. International Journal of Biological Macromolecules 224, 319-343 (2023).
2. Mirdita, M., Schütze, K., Moriwaki, Y. et al. ColabFold: making protein folding accessible to all. Nat Methods 19, 679–682 (2022).
3. Jumper, J., Evans, R., Pritzel, A. et al. Highly accurate protein structure prediction with AlphaFold. Nature 596, 583–589 (2021).
4. Varadi, M. et al. AlphaFold Protein Structure Database: massively expanding the structural coverage of protein-sequence space with high-accuracy models. Nucleic Acids Res. 50, D439–D444 (2022).
5. Zhao, F., Zhang, T., Sun, X. et al. A strategy for Cas13 miniaturization based on the structure and AlphaFold. Nat Commun 14, 5545 (2023).
6. Jun Cheng et al. Accurate proteome-wide missense variant effect prediction with AlphaMissense. Science 381, 7492 (2023).
Ferritin is a protein complex responsible for storing iron in various organisms. One of the most important properties of ferritin is the spontaneous formation of a spherical hollow protein globule consisting of 24 subunits, this process is called self-assembly [1]. The protein globule is very stable and can sustain significant temperature and pH changes [2]. The self-assembly process plays a crucial role in the functioning of such proteins; however, its molecular mechanism has not been fully understood [3]. Closer look on the self-assembly mechanism might be useful for studying different oligomeric states of ferritin, which may help in the development of recombinant ferritin-based vaccines.
In this work, recombinant protein complexes based on ferritin from H. pylori were obtained. The constructs contained apoferritin with different modifications of the N-terminal region. The resulting protein complex models were made using high-resolution structures from Protein Data Bank and their Dmax are 12 nm and 20 nm, respectively.
The expression and the purification were performed under similar conditions for each of the obtained protein constructs. Briefly, the expression was carried out using culture media at 37°C for 3 hours after reaching OD of 0.6 (approximately 5 hours after autoinduction). The purification was performed using buffer containing 20 mM Tris base at pH 8.1, with immobilized metal chelate affinity chromatography (IMAC) and SEC. Recombinant protein complexes were obtained, consisting of 24 subunits according to negative staining transmission electron microscopy (NS-TEM) and small-angle X-ray scattering (SAXS).
The experiments, studying the possibility of exchange of subunits between two protein complexes under various conditions, were carried out. Briefly, the samples of first and second constructs, and their equimolar mixture were transferred to conditions with different pH. To control the results SEC and Blue native electrophoresis ([4]) were used. As a result, the stability of globules of recombinant protein complexes based on apoferritin was confirmed in a wide range of conditions (up to pH 12). Moreover, conditions for the disassembly of protein globules of modified apoferritin have been found; the resulting oligomeric states require further study.
We acknowledge the support from the Ministry of Science and Higher Education of the Russian Federation (agreement # 075-03-2023-106, project FSMG-2021-0002).
Literature list
1. Zhang, Y. Self-assembly in the ferritin nano-cage protein superfamily / Y. Zhang, B.P. Orner // International Journal of Molecular Sciences. — 2011. — Vol. 12(8).
2. Structure, function, and evolution of ferritins / S.C. Andrews, P.M. Harrison, S.J. Yewdall et al. // Journal of Inorganic Biochemistry. — 1992. — Vol. 47(1).
3. Ferritin self-assembly, structure, function, and biotechnological applications / V.V. Sudarev, S.M. Dolotova, S.M. Bukhalovich et al. // International Journal of Biological Macromolecules. — 2023. — Vol. 224.
4. Schägger, H. Blue native electrophoresis for isolation of membrane protein complexes in enzymatically active form / H. Schägger, G. von Jagow // Anal Biochem. — 1991. — Vol. 199(2).
Abstract— We report the different pulse duration of UVB laser radiation cytotoxic effect on human skin fibroblasts. The shorter the pulse, the less viable the cells. According to MTT test examined 24 hours after irradiation cells have the potential to recover. Regarding flow cytometry, we concluded that the toxicity is concerned with the lipid membrane destruction.
Vitiligo is the depigmentation disease characterized by loss of epidermal melanocytes [1]. The two most effictive methods of vitiligo treatment are psoralen plus ultraviolet A (PUVA) and narrowband ultraviolet B (NB-UVB), but nowadays PUVA practically not used because of its aggressive phototoxicity and carcinogenic effects on cells [2]. NB-UVB first used in vitiligo in 1997 [3]. The wavelength which used was 310-315 nm with peak emission at 311 nm. This unique wavelength is effective possibly because it can stimulate non-active epidermal melanocytes and modulate cutaneous immune system [4]. However, simultaneously with “treatment” of skin melanocytes most of other cells are negatively affected by UVB-irradiation. Reactive oxygen species (ROS) are formed in fibroblasts, that causes various damages [5]. In this work we studied new perspective methods of vitiligo treatment which will cause less or no side effects.
II. METHODS AND RESULTS
We investigated a relation between cells viability and time of irradiation, impulse’s duration and timing of the MTT assay. We have used the laser radiation of LiLiYF4:Ce+Yb active medium, which provides generation of sub-nanosecond pulses and wavelength tuning in UVB range [6,7]. It has been shown that the survival of fibroblast cells is less when irradiated with UV light with a shorter pulse duration (1 ns) Fig. 1(a). When we examined cell viability 24 h after irradiation Fig. 1(b) we found increasing in HSF cells viability. As shown in Fig. 1(c) After 24 h viability of HSF cells that were irradiated at wavelength 300 and 310 nm was less than control. Whereas, in the last sample (325 nm) viability was increased quite a lot. It was established by flow cytometry that as a result of UV laser irradiation of fibroblasts, the cytoplasmic membrane is damaged in 80% of cases Fig. 1(d).
Fig. 1. Cell viability right after irradiation (a) Cell viability 24 hours after irradiation (b) Effect of different wavelength to HSF cells viability 24 hours after irradiation (c) Table of the results of flow cytometry, DiOC6+PI- (alive) I, DiOC6-PI- (with damaged mitochondria) II, DiOC6-PI+ (dead, late apoptosis) III, DiOC6+PI+ (perforated cytoplasmic membrane) IV (d)
Authors are thankful for RSF 20-73-10029 project of SPbSU. The UV laser was elaborated within KFU Strategic Academic Leadership Program (PRIORITY-2030).
REFERENCES
[1] Esmat, S., Hegazy, RA., Shalaby, S., Hu, S. Chu-Sung, Lan, Cheng-Che E. (2017). Phototherapy and Combination Therapies for Vitiligo. Dermatol Clin., 35, 171–192
[2] Kishan Kumar YH, Rao GR, Gopal KV, Shanti G, Rao KV. (2009). Evaluation of narrow-band UVB phototherapy in 150 patients with vitiligo. Indian J Dermatol Venereol Leprol.; 75, 162–6.
[3] Westerhof W, Nieuweboer-Krobotova L. (1997). Treatment of vitiligo with UV-B radiation vs topical psoralen plus UV-A. Arch Dermatol.13, 1525–8.
[4] Kanwar AJ, Dogra S, Parsad D, Kumar B. (2005). Narrow-band UVB for the treatment of vitiligo: An emerging effective and well-tolerated therapy. Int J Dermatol. 44, 57–60.
[5] De Souza, R. O., de Assis Dias Alves, G., Aguillera, A. L. S., Rogez, H., & Fonseca, M. J. V. (2018). Photochemoprotective effect of a fraction of a partially purified extract of Byrsonima crassifolia leaves against UVB-induced oxidative stress in fibroblasts and hairless mice. Journal of Photochemistry and Photobiology B: Biology. 178, 53–60.
[6] Nizamutdinov, A.S., Semashko, V.V., Naumov, A.K., Korableva, S.L., Marisov, M.A., Efimov, V.N., Nurtdinova, L.A. Characterization of Ce3+ and Yb3+ doped LiF-LuF 3-YF3 solid solutions as new UV active media (2011) Proceedings of SPIE - The International Society for Optical Engineering, 7994, paper № 79940H
[7] Ultra-short pulses UV lasing in multifunctional Ce:LiY0.3Lu0.7F4 active medium, Farukhshin, I.I., Nizamutdinov, A.S., Korableva, S.L., Semashko, V.V., Optical Materials Express, 2016, 6(4), стр. 1131–1137
Modern pixel particle detectors allow possibility to determine coordinates of hit with high accuracy. Some of them, for example Medipix series detectors, provide possibilities to evaluate particle energy deposit. However, pixel detectors have a difficult problem of a dividing of the charge, appeared by interaction with hitting particle, into neighbor pixels.
To compensate this effect the clusterization procedure is used. The clusterization procedure is the process of union of neighbor non-zero pixels. A cluster is a group of pixels with common borders. Sum of energy deposit in pixels of a cluster provide estimation of particle energy with higher accuracy. The clusterization procedure usually operates with ready data saved on a computer what required a long time and big amount of memory. Here the clusterisation algorithm for FPGA to include in DAQ systems of pixel detectors is presented. The including clusterization procedure in DAQ reduces amount of memory and time required for data processing.
A Monte-Carlo model of the beam position detector was developed for measurement of an low-intensity electron beam profile. The detector is an octagonal-shaped scintillator. The simulation of interaction of electrons with detector and photon transportation was done. Three reconstruction methods of interaction position were suggested.
The root mean square charge radius is one of the most interesting characteristics of the atomic nucleus. By studying changes in this parameter in a chain of isotopes of one element, one can make conclusions about how the structure of the nucleus changes when the number of neutrons changes, as well as how accurate nuclear theory describes the dependencies obtained in the experiment. In the case of short-lived isotopes, the main experimental method for determining the charge radius is the measurement of isotope shifts of transition energies in atoms.
To interpret such experiments, it turns out that it is necessary to carry out calculations of the electronic structure with the calculation of field and mass shift constants. The field shift constant is related to the different charge distribution over the nucleus for the isotopes under consideration, and the mass shift constant is related to the nuclear recoil effect. We have developed a method for carrying out theoretical calculations of these constants with a detailed analysis of the resulting uncertainties. It was shown that the technique used makes it possible to obtain a significantly higher accuracy of isotope shift factors [1-3]. The results obtained were used in the interpretation of the experiment for a number of neutron-deficient isotopes of thallium [4]. In addition, to interpret future experiments, calculations were carried out for gold and aluminum atoms.
The research was supported by the Russian Science Foundation grant 19-72-10019-P.
[1] Filippin, L., Beerwerth, R., Ekman, J., Fritzsche, S., Godefroid, M., Jönsson, P. Phys. Rev. A, 94(6), 062508 (2016).
[2] Heylen, H., et al., High-resolution laser spectroscopy of Al 27–32. Physical Review C, 103(1), 014318 (2021).
[3] Rosen, A., Fricke, B., Torbohm, G. Zeitschrift fur Physik A Atoms and Nuclei, 316(2), 157-16 (1984).
[4] G. O. Penyazkov, S. D. Prosnyak, A. E. Barzakh, L. V. Skripnikov, J. Chem. Phys. 158, 114110 (2023).
In order to better understand the dynamics of the quark hadron phase transition in the presence of a magnetic field, the thermal behaviour of the non-perturbative QCD vacuum has been examined. The dynamical configuration of the resulting dual QCD vacuum and its flux tube configuration have been explored in order to investigate the nonperturbative properties of QCD. Within the context of dual QCD-based hadronic bag, which ensures the critical parameters and the accompanying critical sites for quark-hadron phase transition, related pressure and entropy density to define quark matter have been studied in presence of magnetic field.
We investigate effects of nonzero Dirac and Majorana CP-violating phases on neutrino-antineutrino oscillations in a magnetic field of astrophysical environments. It is shown that in the presence of strong magnetic fields and dense matter, nonzero CP phases can induce new resonances in the oscillations channels $\nu_e \leftrightarrow \bar{\nu}_e$, $\nu_e \leftrightarrow \bar{\nu}_\mu$ and $\nu_e \leftrightarrow \bar{\nu}_{\tau}$. The resonances can potentially lead to significant phenomena in neutrino oscillations accessible for observation in future neutrino telescopes, such as JUNO, Hyper-Kamiokande and DUNE. In particular, we show that neutrino-antineutrino oscillations combined with Majorana-type $CP$ violation can affect the $\bar{\nu}_e$/$\nu_e$ ratio for neutrinos coming from the supernovae explosion.
Muon decay spectrum (energy spectrum of an electron in muon decay) can give information about weak interaction and Standard Model in general. Leptonic decays of leptons, such as muon and tau lepton, are a “pure laboratory” for testing the Standard Model and searching for new physics. For such processes, high-precision and highly sensitive experiments can be carried out, in which small deviations from the Standard Model can be seen. For theoretical description and prediction of the results of such experiments it is necessary to calculate the radiative corrections with high precision. Full non-polarized radiative corrections in leading and next-to-leading logarithmic approximations to the \alpha^3 order are presented.
The study of the scattering process associated with the one-dimensional matrix Schrödinger equation is a classical pursuit within the realm of quantum theory. A comprehensive examination of the overarching characteristics of such scattering processes along a semi-axis, in particular the rigorous verification of unitarity in the context of the S-matrix with closed scattering channels, can be found in the the book ([1], Chap. 17). The inverse scattering problem for the one-dimensional Schrödinger equation on the whole axis in the case of single-channel scattering was solved by Fadeev [2-4]. In the context of multichannel scattering, which occurs over the entire real line, substantial research has been carried out, in particular in relation to the inverse scattering problem and the derivation of exact solutions for hierarchies of integrable nonlinear partial differential equations [5]. To the best of our knowledge, there is an unaddressed gap in the existing literature regarding the elucidation of the properties associated with the S-matrix, the Jost solutions and the existence of bound states in the general scenario involving multichannel scattering on a line with different threshold conditions existing on both the left and right limits of infinity.
Within the framework of this particular scattering problem, we embark on an analysis of the analytical structure characterising the Jost solutions and the transition matrix relating the Jost solutions as functions of the spectral parameter [6]. In addition, we provide the proof of unitarity for the scattering matrix under the more general circumstances where certain scattering channels may be closed and there are disparities in the threshold parameters at the left and right limits of the infinite line. In addition, we establish a necessary and sufficient condition that specifies the exact locations of bound states. While the formal expression of this condition is well documented in the context of multichannel scattering, as outlined in previous literature [5, 7, 8, 9], we demonstrate its applicability to the particular scenario of a scattering problem characterised by distinct thresholds at both the left and right extremes of infinity.
The results of the thesis are applicable in the electrodynamics of continuous media, in the theory of sound wave propagation, in the description of the passage of electrons through heterostructures, in quantum chemistry, in hydrodynamics and plasma physics, etc. In particular, when describing photon scattering through metamaterials with large spatial dispersion, the problem of proving the unitarity of the S-matrix in open channels arises.
The work was funded by the RSF project 21-71-10066.
[1] Newton, R. G.: Scattering Theory of Waves and Particles. Springer-Verlag, New York (1982)
[2] Faddeev, L. D.: On the connection between the S-matrix and the potential for the one-dimensional Schrödinger operator [in Russian]. DAN SSSR 121, 63-66 (1958)
[3] Faddeev, L. D.: Properties of the S-matrix of the one-dimensional Schrödinger equation [in Russian]. Trudy Mat. Inst. Steklov 73, 314 (1964)
[4] Faddeev L. D.: Inverse Problem in quantum scattering theory. II [in Russian]. Itogi nauki i techn. Ser. Sovrem. probl. mat. 3, 93-180 (1974)
[5] Zakharov, V. E., Manakov, S. V., Novikov, S. P., Pitaevskiy, L. P.: Theory of solitons: method of inverse problem [in Russian]. Nauka, Moscow (1980)
[6] P. O. Kazinski, P.S. Korolev.: Multichannel scattering for the Schrödinger equation on a line with different thresholds at both infinities, arXiv:2307.00473 (2023)
[7] Wadati, M., Kamijo, T.: On the Extension of Inverse Scattering Method. Prog. Theor. Phys. 52, 397–414 (1974)
[8] Wadati, M.: Generalized matrix form of the inverse scattering method. Solitons, 17, 287-299 (1980)
[9] Bondarenko, N.: Inverse scattering on the line for the matrix Sturm–Liouville equation. J. Differ. Equ. 262, 2073-2105 (2017)
The process of double Compton scattering, eγ→eγγ , in a strongly magnetized charge-asymmetric cold electron plasma is considered.The amplitude of the process is obtained for case when the electrons are at an arbitrary Landau level. The expressions for the amplitude of the process in the magnetar case have been obtained. The double Compton scattering in such a plasma is shown to be an efficient process for the production of polarized photons.
On Halloween night you will be given a lecture in the dark. There have been many dark spots in the lives of scientists who are the pioneers of particle physics and nuclear physics, but also many funny moments. From the lecture you will learn about funny incidents, dark events and relationships between the great scientists of the past. It will be told how important its majesty of chance is in science.
The high-resolution Fourier diffractometer (HRFD) has been in routine operation since 1994 at the long-pulse neutron source, the IBR-2 reactor, in Dubna. Its fast Fourier chopper provides probably the best compromise between very high resolution in reciprocal space (Δd/d ≈ 0.001) and the intensity. For further improving intensity of TOF-diffraction pattern, a wide-aperture ring backscattering detector (BSD) has been developed on the basis of ZnS(Ag)/6LiF scintillator. BSD is designed in the form of 6 concentric rings, each of which is subdivided into 12 identical parts. The main parameters of the detector are the following: range of scattering angles is 2θ = (133 - 175) degrees, covered solid angle is Ωd ≈ 2.0 sr, average percentage absorption efficiency gets closer to 85%, geometrical contribution to resolution function does not exceed Δd/d = 0.0005. In the report the concept of the detector is described and its data acquisition system is presented. The start of operation of the detector at the HRFD is scheduled for 2024.
Thermal transport in α-Al2O3 irradiated with 167 MeV Xe ions is investigated within direct method based on the Fourier law implemented into classical molecular dynamics. Formation of defective regions as a result of ion passages is described using the original multiscale approach developed in previous works. Thermal conductivity degradation of single-crystalline alumina with ion fluence shows reasonable agreement with the experimental thermoreflectance data. The imposed method demonstrated good applicability in the considered case and allowed to distinguish effects of discontinuous crystalline tracks on thermal conductivity of the alumina target.
The discovery of an increase in the magnetostriction of α-Fe with partial substitution of iron with gallium [1] has led to a significant amount of research, where a similar effect was sought in various binary (Fe-Al, Fe-Ge, Fe-Si, etc.) and ternary (Fe-Ga-Al, Fe-Ga-Ge, etc.) iron-based alloys. Currently, there is a considerable number of studies on the structure and properties of Fe-Ga alloys (enhanced magnetostriction) and Fe-Al alloys (improved mechanical properties) [2]. However, structural studies on ternary Fe-Ga-Al alloys (promising in terms of a combination of mechanical and magnetic properties) are practically absent. Another interesting structural topic is the investigation of the influence of rare earth elements (RE), such as Tb, Dy, Ce, Y, Er, Pr, Sm, La, on the characteristics of Fe-Ga alloys. The physical and technical properties of these functional materials largely depend on their specific atomic structure, the volume fraction of various structural phases, and their microstructural state.
In this work, research on the evolution of structural phases and the microstructural as-cast state of compositions Fe100−(x+y)GaxAly in the range 17 ≤ (x + y) ≤ 39 at.% [3] and Fe100-(x+y)GaxREy, (with x = 27.4% and 26.7%), where rare earth elements Er (y = 0.5% and 0.2%) and Yb (y = 0.5% and 0.24%) were used, is presented. The results were obtained through neutron diffraction experiments conducted with high resolution and in continuous temperature scanning mode, heating up to ~900°C and subsequent cooling. Information about the microstructural state was obtained through analysis using the Williamson-Hall method and the method for determining grain size and its distribution along the diffraction line profile [4].
References:
1. A. E. Clark, J. B. Restorff, M. Wun-Fogle, T. A. Lograsso, and D. L. Schlagel, IEEE Trans. Magn. 36, 3238 (2000)
2. I. S. Golovin, V. V. Palacheva, A. K. Mohamed, A. M. Balagurov, Physics of Metals and Metallography. Vol. 121, № 9. p. 937–980 (2020)
3. A. M. Balagurov, I. A. Bobrikov, S. V. Sumnikov, B. Yerzhanov, D. G. Chubov, V. V. Palacheva, I. S. Golovin, Physics of the Solid State. Vol. 64, № 12, p. 1873-1881 (2022)
4. R. Pielaszek, J. Alloys Compd. (2004). 382, 128–132.
Half-Heisler magnetic intermetallic compounds of transition metals exhibit interesting physical properties such as magnetoresistance, ferromagnetic and antiferromagnetic magnetic states, and superconductivity. It is observed the shape memory effect and superelasticity with opportunity to control there phenomena by means magnetic field. It makes these compounds promising materials to apply for creation permanent magnets, elements of electronic devices and cooling technology.
In our work we present the results of investigation the crystal and magnetic structure of half-Heusler intemetallic compounds MnNiSb and MnNi0.9M0.1Sb (M = Ti, V, Cr, Fe, Co, Zn) by means of neutron diffraction in the temperature range 10–300 K and by X-ray diffraction in the pressure range 0–30 GPa at room temperature.
It has been found that the initial cubic structure F4 ̅3m and ferromagnetic phase remain in the investigated temperature range. New reflections correspond to the antiferromagnetic phase have been found. Partial substitution of another transition element for nickel leads to a decrease in the magnetic moment of the Mn ions. Under high pressure, the cubic structure F4 ̅3m remains stable for all compounds under study.
This work have been supported by the Russian Foundation for Basic Research, project no. 20-52-04003 Bel_mol_a (Belarusian Foundation for Basic Research, project no. T21RM-029).
Bragg scattering on a crystal is possible only if the wavelength of the radiation does not exceed the double distance between the crystal planes. Usually, in natural crystals, the interplane distance does not exceed ~ 2 Å, so neutrons with a wavelength of more than ~4 Å cease to scatter on them. It is due to this property that such neutrons are allocated to a separate group called cold neutrons. However, it is possible to create artificial crystals whose interplane distance can be several times greater. Usually, in the production of such crystals, a graphite single crystal is taken as a basis, and atoms of another substance are introduced between its crystal planes, which push the graphite planes apart. Thus, intercalated graphite is obtained, which can effectively scatter cold neutrons. However, such crystals are not sufficiently radiation-resistant to be used near the reactor core.
Not so long ago, the technology of embedding a whole plane (or two planes) of fluorine atoms between graphite planes appeared. Such a material seems promising as a cold neutron reflector, which can be used in strong fields of ionizing radiation. Preliminary results of structural studies and measurements of neutron scattering cross sections with such materials will be presented in the report.
Photoelectrochemical (PEC) water splitting is a promising method for environmentaly benign production of energy in the form of chemical fuels. Monoclinic bismuth vanadate (BiVO4) stands out as an excellent candidate for photoanode material due to its suitable band structure, good stability and low-cost synthesis. However, BiVO4 has poor charge transfer properties due to the high rate of electron-hole recombination and understanding the effects contributing to it is important for further improvements. Herein, we report the effect of swift heavy ion irradiation (Xe, 150 MeV, 1 × 1010 – 5 × 1011 ions/cm2) on physicochemical properties of hydrothermally synthesized BiVO4 thin films. X-ray diffraction study (XRD) showed that irradiated material preserved initial monoclinic scheelite phase and preferential growth along [010] direction together with the presence of notable amorphization for 5 × 1011 ions/cm2 irradiated sample. Scanning electron microscopy (SEM) of all samples showed prismatic grains with an average size of 600 nm. In irradiated samples formation of ion tracks, ~ 10 nm in diameter, was observed. Raman spectroscopy analysis confirmed presence of bands that correspond to the monoclinic scheelite phase along with the appearance of new bands for 5 × 1011 BiVO4 at 420 and 915 cm-1. X-ray photoelectron spectroscopy (XPS) analysis of Bi 4f, V 2p and O 1s states showed that, after irradiation, increased amounts of V4+ and oxygen vacancies occured, especially at higher fluences. By using UV-Vis Diffuse Reflectance spectroscopy we showed that band gap decreased with the increase in fluence. Photocurrent densities, obtained from 1-hour-long chronoamperometry measurements, indicated that irradiation with 1 × 1010 ions/cm2 fluence leads to the enhanced PEC oxygen evolution with time. In order to get a better insight into preceding phenomena, we performed XRD, SEM and XPS analysis after PEC processs.
The report is devoted to the ongoing experiment of the JINR DLNP which is dedicated to the study of double beta decay of the Zr-96 isotope and the experimental detection of the decay mode to excited states of Mo-96. It covers the description of the experimental setup, results of the Monte-Carlo modeling of experiment in Geant4 and preliminary analysis of future prospects
The νGeN experiment is aims to search for coherent elastic neutrino-nucleus scattering (CEνNS) and to study the neutrino properties. A low-background 1.4 kg HPGe detector with energy threshold less than 300 eV is used to detect CEνNS. The νGeN is located about 11 meters from the center of the 3.1 GWth reactor #3 of Kalinin NPP, which is leading to an antineutrino flux of (3.9-4.4)*10$^{13}$ cm$^{-2}$ s$^{-1}$. The reactor and surrounding materials provide about 50 m.w.e. shielding from cosmic rays. The intense antineutrino flux and high overburden gives a possibility to detect coherent elastic scattering of reactor antineutrinos on Ge nuclei in the fully coherence regime, as well as to study other properties of neutrinos. The current status of the experiment will be presented.
This work has been partly supported by the Ministry of science and higher education of the Russian Federation (the contract no. 075-15-2020-778).
Scintillation detectors based on CsI(Tl) crystals are a widely used instrument in nuclear physics,especially in the field of gamma-ray spectrometry and/or fast light charged particles. Large CsI(Tl) crystals like ours with a volume of ~370 cm3 , are used in many collaborations [1-3].
GADAST (GAmma-ray Detector Around the Secondary Target) is a compact detector array as a part of EXPERT setup [3], intended to be located in the middle of the Super-conducting FRagment Separator (Super-FRS) facility, situated at the Facility for Antiproton and Ion Research (FAIR), Darmstadt, Germany. The array consists of 128 CsI(Tl) and 32 LaBr3 scintillators coupled with photomultipliers and is designed mainly to detect gamma radiation from the de-excitation of secondary beam heavy fragments, produced in two-proton radioactivity processes. Such processes are of great interest because the mechanisms of their formation are poorly understood, and many of the isotopes that possess this phenomenon are either insufficiently studied or completely undiscovered. An example of an experiment with GADAST is a study of properties and potential proton radioactivity of an exotic isotopes 5Be, 6B, 7C and 9N.
In this work the properties of CsI(Tl) based detectors were investigated. Characteristics that were measured are energy resolution and non-uniformity of the light output. ExpertRoot package [4], which uses Monte Carlo methods for simulating particle interactions, was employed to simulate the experimental setup, in order to study the influence of various parameters on the final spectrum. We implemented an original algorithm for modeling the signal overlaps observed due to the high intensity of the gamma-ray sources. In the future, we plan to use the pulse pile-up algorithm when GADAST modules will be located in the region of a target bombarded by a heavy ion beam with high intensity. We also modeled the non-uniformity of the light output, as it may be necessary to consider it when working with large-size crystals like those used in GADAST.
References
1. A. Knyazev et al., Nucl. Instrum. Methods Phys. Res. A, 2019, p. 393-404
2. G. Li et al., Nucl. Instrum. Methods Phys. Res. A, 2021, 165637
3. https://edms.cern.ch/document/1865700/2, Technical Report for the Design, Construction and Commissioning of the setup EXPERT: Exotic Particle Emission and Radioactivity by Tracking
4. http://er.jinr.ru/, ExpertRoot documentation
DUNE is a long-baseline neutrino accelerator experiment planned for construction in the USA. To achieve its goals, DUNE employs two large-scale detectors: the Near Detector and the Far Detector. Far Detector will utilize a liquid argon time projection chamber (LArTPC). The Near Detector will use a similar approach in neutrino detection and thus a modular LArTPC is planned to be used.
Currently, a program is underway to test prototypes of modular liquid argon time projection chambers (LArTPC) at the University of Bern in Switzerland. We have developed a light readout system for registration scintillation light produced when charged particles interact with liquid argon. The report will present the results of launching and testing the light system of an additional LArTPC prototype in the cryogenic laboratory at the University of Bern.
The mass is a fundamental property of an atom comprising all information on its constituents and their interactions. Thus, it carries information on the internal structure of the nucleus, reveal the quantum mechanical shell structure within complex nuclei and determine the energy available for nuclear transformations in radioactive decay processes. Mass measurements allow us to benchmark nuclear models and thus contribute to investigations of the nature of the strong interaction itself. With the aim of high-precision mass measurement (HPMM) of heavy and super heavy elements, a new experimental setup is being built in FLNR, Dubna. The setup consists of the following parts: target unit; gas-filled separator of complete fusion reaction products; cryogenic gas stopping cell (CGSC); a radio-frequency system for transporting and cooling a low-energy beam; and a multi-reflection time of flight mass spectrometer (MR-TOF MS). CGSC is responsible for the final slowing down and thermalizing the energy-bunched fragments produced and selected in the Gas Filled Separator. The thermalization is achieved in a volume filled with ultra-pure helium gas at cryogenic temperatures. After the thermalization, the fragments are extracted and transported with a radio frequency quadrupole (RFQ) to the MR-TOF MS. The stopping and thermalization of the incoming fusion-evaporation residuals (EVRs) is a key step in HPMM of the heaviest elements. Due to the typically low incoming ion rates and low particle integrals CGSC has to be as efficient as possible. Only the ions that are stopped within the active gas volume of the CGSC can be extracted. The stopping efficiencies for EVRs cannot be verified online and must be relied upon by simulations. To use the CGSC on ion beam the optimal entrance window foil thickness for every reaction is necessary to evaluate. Simulations were performed to determine the efficiency and extraction time from a cryogenic gas ion cell for products arising in the following complete fusion reactions: 40Ar+144Sm->184Hg, 40Ar+166Er->206Rn, 48Ca+197Au->245Es, 48Ca+208Pb->256No, 48Ca+209Bi->257Lr and 48Ca+242Pu->290Fl. Based on the software packages SRIM2013, GEANT4, ROOT, SIMION and COMSOL, two programs were created. The first program calculated the efficiency of capture of reaction products as a function of the thickness of the entrance window and the helium pressure in the cryogenic gas ion trap. The second program determined the efficiency and extraction time of the captured products. To test a gas trap without a beam using an alpha source, the efficiency and extraction time from the trap of the progeny of the alpha source were calculated. The calculations were carried out for different helium pressures and depending on the position of the alpha source in the gas ion trap.
Instrumental neutron activation analysis is performed at the REGATA facility of the IBR-2 reactor. The main stages of the analysis are samples preparation and irradiation, acquisition and processing of gamma spectra, and analysis of the data obtained. Four pairs of KUKA KR10 R1100 robotic manipulators and Canberra DSA-LX multichannel analyzers are used to automate the acquisition of gamma spectra of irradiated samples. This set of devices allows simultaneous measurement of eighty-one samples on one detector without operator intervention. Special software has been written to control these devices, perform an automatic sample changing and acquisition of gamma spectra.
The main stages of software development include writing class libraries for controlling KUKA KR 10 R1100 robotic manipulators and Canberra DSA-LX multichannel analyzers and creation of user graphical interface.
The development was carried out in the object-oriented programming language C# using the .NET Framework. This combination of programming tools will allow to run the application on Windows PC and make modifications to apply new functional and hardware features. The graphical shell was made using the UI framework Windows Forms.
The software application allows to work simultaneously with a selected number of “detector-robot” pairs, transmit measurement information to the database and save locally spectrum files.
The BM@N 8th physics run using Xenon ion beams was successfully completed in February 2023, resulting in the recording of approximately 550 million events. They were recorded in the form of 31306 files, with a combined size exceeding 430TB. However, the reconstruction of these files demands significant computing resources, which is why a distributed infrastructure unified by DIRAC was chosen for this task. The first objective was to transfer the raw files from EOS in LHEP to DIRAC storage, based on EOS in LIT. This was achieved through parallel transfer using multiple independent DIRAC jobs. Once the data was accessible by all the resources integrated in DIRAC, the profiling of digitization and reconstruction jobs were performed to determine the computing resource requirements. For the digitization step three computing resources were selected: Tier1 and LHEP for 99% of the files, and Govorun for large files ranging from 16 to 250 gigabytes. Finally, Tier1, Tier2, and LHEP clusters were utilized to reconstruct the files obtained after digitization. The BM@N 8th physics run in February 2023 was the first time DIRAC had been used for raw data reconstruction in JINR in production rather than just in test mode. As a result, a set of approaches, systems, and methods were developed during this campaign, which will aid in reducing the efforts required for future data reconstructions at JINR.
Modern scientific research and megascience experiments cannot exist without large-scale computing systems that enable to store large amounts of data and process them in a relatively short time. Such systems are distributed data acquisition, storage and processing centers. Large-scale distributed computer systems have a complex structure, include many different components and provide shared access to data storage and processing resources. Such systems must continuously guarantee high-quality and efficient operation. Therefore, a digital twin is needed for the design, support and development of distributed computer systems. It should allow one to investigate system reliability, check various scaling scenarios, find the necessary amount of resources to solve specific tasks.
The Meshcheryakov Laboratory of Information Technologies (MLIT) of the Joint Institute for Nuclear Research (JINR) has developed a prototype of a software complex for creating digital twins of distributed data acquisition, storage and processing centers. The talk will present development usage examples for the computing infrastructures of the BM@N and SPD experiments of the NICA project. The examples confirm the possibility of further use of the software complex in the design and modernization of various computing infrastructures for megascience projects.
This work is supported by JINR grant for young scientists No. 23-602-03.
A huge amount of experimental data should be collected, stored and processed in large modern high-energy physics experiments, including the experiments of the NICA project at the Joint Institute for Nuclear Research. In this regard, corresponding performance requirements are put forward for existing online systems. The Online Data Processing System developing for the BM@N experiment of the NICA project is based on a distributed architecture that allows it to meet high performance requirements due to the possibility of scaling and parallel computing. The purpose of the online system is selective data processing (event digitizing and fast reconstruction) and data monitoring of the ongoing experiment. To achieve this goal, the FairMQ package developed by the FAIR collaboration (GSI Institute, Germany) has been chosen to communicate distributed processes executed on the nodes of the computing infrastructure with each other through the exchange of messages. One of the issues in developing and using such systems is the problem of the distributed run and control of the processes. The task is solved by using the FAIR DDS (Dynamic Deployment System) toolkit. The BM@N online system should start the predefined software tasks in the required sequence and allows managing them during sessions, including the transmission of messages between tasks and the update of some properties. The report presents the purposes and architecture of the developing Online Data Processing System for the BM@N experiment and features of the current implementation.
In high-energy physics experiments the ability to display both detector geometry and particle tracks has become an essential feature, required for physicists to better understand particular collision events as well as to present the physical results to a wider audience. Currently, most experimental collaborations build their own event display solutions with little to no unification between them. In this work, a new event visualization solution for the BM@N (Baryonic Matter at Nuclotron) experiment is presented, a fixed target experiment of the NICA (Nuclotron-based Ion Collider fAcility) project. The solution is based on VisionForge, a modern open-source visualization system. An important part of the solution is integration of the system with experiment's software framework BmnRoot, which is a CERN ROOT-based environment. Several possible methods of such integration are discussed and the established architecture of the next-generation visualization system is explained.
The DSpace software platform created specifically for creating digital archive systems, organizing access, long-term storage and preservation of digital content. DSpace allowing researchers and scientists to publish their documents and data. It is open source software, this with cooperation of rich functionality make it an attractive software for academic, non-profit and commercial organizations, creators of open digital repositories.
The talk will discuss the possible usage of the Dspace platform for the JINR repository. A test web interface will be presented, which supports English and Russian languages, schemes for obtaining metadata from external resources such as Inspirehep, Scopus, eLibrary, as well as plans for the future to expand the usage of the Dspace platform and adapt it to the tasks of the JINR institutional repository.
The software infrastructure of the BM@N experiment contains a set of various information systems that are essential for the work with experimental or simulated data on all processing stages, including the collection, storage, intermediate processing and physics analysis. Some examples of the systems are the Electronic Logbook Platform, Condition Database and Event Metadata System. In case one of such systems stops functioning, the work with BM@N data by collaboration members gets either impossible or, at least, much less productive. Due to this fact, the timely detection of possible failures in the systems due to software or hardware failures is fairly important. The Monitoring Service described in the report is used to check availability and health status of information systems. This includes measuring, storing, visualizing and sending alert notifications on monitored parameters, such as CPU, memory and disk utilization, DBMS functioning parameters, response times of databases and API endpoints, ping round-trip times, and so on. The current implementation of the BM@N monitoring service is discussed in detail. A related task of building highly available information services is also briefly noted.
We consider a four-dimensional quantum field theory with weakly interacting ultraviolet fixed points up to four loop order for gauge couplings, three loop to Yukawa and quartic scalar beta functions. We compute them for a template SU(Nc) gauge theory coupled to Nf fundamental fermions and elementary scalars.
Moreover, we found fixed point couplings, field and mass anomalous dimensions, and universal scaling exponents up to the first three non-trivial orders in a small Veneziano parameter. Further, we investigate the size of the conformal window.
The WASA@COSY collaboration observed in the total cross section of reaction $pn->dπ^0π^0$ a clear dibaryon resonance in a non-strange sector with a mass of 2380 MeV and a remarkably narrow width of 70 MeV [1]. Later on the ANKE@COSY also found indications to excitation of this dibaryon in other reaction, $pd->pdππ$ [2]. For explanation of the ANKE@COSY data we applied the two-resonance model [3] to the reaction by inclusion of the $t-$channel $σ-$meson exchange between the proton and deuteron [4]. In this talk we extend the model [4] of the reaction $pd-pdππ$, taking into account the recent results of Ref. [5], where the $Δ(1232)Δ(1232)$ resonances channel was introduced in addition to the $d^*(2380)-> D(2150)+π-> d+ ππ$ and $d^*(2380)-> d+σ->d+ππ $ channels of the decay of the $d^*(2380)$ resonance in describing the reaction $pn->dπ^0π^0$.
The research is supported under the grant № 411 of the Scientific Program JINR – Republic of Kazakstan.
[1] P. Adlarson et al., Phys. Rev. Lett. 106, 242302 (2011).
[2] V.I. Komarov, et al. Eur. Phys. J. A 54, 206 (2018).
[3] M.N. Platonova, V.I. Kukulin, Phys. Rev. C 87, 025202 (2013).
[4] Yu.Uzikov, N. Tursunbayev, EPJ Web of Conferences 204, 08010 (2019)
[5] M. N. Platonova, V. I. Kukulin, Phys. Rev. D 103, 114025 (2021)
The report is devoted to the theoretical study of the problem of producing heavy neutron-rich nuclei with a closed neutron shell N=126. Data on the lifetime of such new nuclei, as well as mass, decay modes, excited levels, etc., are of great value for testing and developing theoretical models of atomic nuclei. Also, these nuclei form one of the special waiting points in the r-process path, and hence their properties are of great importance in understanding the detailed scenario of the r-process of astrophysical nucleosynthesis.
Typically, nuclei from this region are obtained in fragmentation reactions of high-energy heavy projectiles on light targets. Currently, the possibility of studying new isotopes in this area using multinucleon transfer (MNT) reactions is widely discussed. One of the most optimal combinations of colliding nuclei, in which multinucleon transfers lead to the formation of heavy neutron-enriched nuclei with high probability, is $^{136}$Xe + $^{198}$Pt. The calculations performed within the framework of the dynamic model based on Langevin equations describe quite well the available experimental data for this reaction [1,2,3].
In this work, one of the possible extensions of this method is studied: the use of neutron-rich radioactive ion beams (RIBs) in MNT reactions [4]. On the one hand, this leads to an increase in the probability of formation of heavy nuclei with a neutron excess, but on the other hand, lower RIB intensities reduce the final yield of reaction products. In this work, we present the theoretical analysis of the yields of heavy neutron-rich isotopes with the magic number N=126 obtained in the $^{132}$Sn, $^{136, 138, 140}$Xe + $^{198}$Pt MNT reactions.
[1] Y. X. Watanabe et al. // Phys. Rev. Lett. — 2015. — Vol. 115. — P. 172503.
[2] V. V. Desai et al. // Eur. Phys. J. A — 2020. — Vol. 56. — P. 150.
[3] A.V. Karpov, V.V. Saiko // Phys. Rev. C — 2017. — Vol. 96. — P. 024618.
[4] C.H. Dasso, G. Pollarolo, and A. Winther // Phys. Rev. Lett. — 1994. — Vol. 73. — P. 1907.
We investigated some characteristics of the behavior of the rotational bands of even nuclei 250−260No and found that for 252No and 254No arises irregularity. Such irrationality is most likely associated not with a change in deformation, but with the evolution of proton and neutron pairing in these nuclei. The study is based on calculations within the Hartree-Fock-Bogolyubov method and the Quantum-Random-Phase-Approximation method. A representative set of Skyrme forces (SVbas, SkM* and SLy6) was also used. The calculations cover the lower spectrum of continuing isotopes up to 2 MeV. An unusual neutron pairing pattern with a strong shell structure effect: the specific evolution of several sequences of particle-hole (1ph) configurations with increasing number of nucleons. Also in the description of the work, quadrupole and octupole bands are possible, which are in good agreement with experimental data.
Using first-principle numerical simulations of the lattice SU(3) gauge theory, we calculate the isothermal moment of inertia of the rigidly rotating gluon plasma. We find that the moment of inertia unexpectedly takes a negative value below the "supervortical temperature" $T_s = 1.50(10)T_c$, vanishes at $T_s = T_c$, and becomes a positive quantity at higher temperatures. The negative moment of inertia indicates a thermodynamic instability of rigid rotation. We derive the condition of thermodynamic stability of the vortical plasma and show how it relates to the scale anomaly and the magnetic gluon condensate.
Doubly-heavy baryons are similar in dynamics to heavy mesons. To describe the latter, an approximation is used in which the heavy antiquark is considered to be static and the light one determines the dynamics of the meson. In the case of a doubly-heavy baryon, the heavy antiquark is replaced by a static doubly-heavy diquark and the dynamics of the system is again determined only by the light quark. The structures of transition matrix elements from the baryon state to the vacuum for both local and non-local interpolation currents are the same as for the heavy-meson matrix elements. In the talk the formalism of describing the $B$-mesons is generalized to the case of doubly-heavy baryons containing both $c$- and $b$-quarks. Transition matrix elements are considered on the light cone and the models of distribution amplitudes proposed for $B$-mesons can be adapted for the doubly-heavy baryons. The exponential model by Grozin and Neubert as well as the linear model by Kawamura et. al. which are dependent on one parameter only - the hadron effective mass - can be easily reformulated for the case of doubly-heavy baryons. The evolution of the baryon distribution amplitudes is also discussed.
Sodium-ion batteries (SIB) are promising electrochemical devices due to the sodium availability compared to lithium. Developing efficient cathode materials is very important task for the wide distribution of SIB. One of the perspective cathode materials for SIB are hexacyanoferrates NaxM[Fe(CN)6]·nH2O (Prussian blue analogues, where M are transition metal cations), which have open framework structure and low-temperature synthesis. For successful using of the material, “y” in Na2-yFe[Fe(CN)6]·nH2O must be minimal. Ideal composition for high SIB capacity is Na2Fe[Fe(CN)6]·nH2O. In scientific research model batteries often use sodium metal anode. In this case the cathode composition can be electrochemically brought to Na2Fe[Fe(CN)6]·nH2O after first charge-discharge cycle of the battery. Real SIBs are manufactured with hard carbon as an anode. It becomes impossible to enrich electrochemically the cathode material with sodium way. Therefore, it is necessary to initially synthesize the Na-rich material.
The structural phase transitions in the commercial PW powder (Altris, Sweden) enriched with sodium, as well as in a similar synthesized Na2-yFe[Fe(CN)6]·nH2O powder during heating up to 250°C and cooling down to -220°C were investigated using X-ray diffraction.
This work was supported the Russian Science Foundation, project No. 21-12-00261.
[1] W. Brant et al. Method of producing a sodium iron(II)-hexacyanoferrate(II) material // United States Patent application publication. No: 2019/0270649 A1, Sep.5 2019.
To date, one of the most relevant areas of condensed matter physics and materials science is the production and study of Bi-activated materials that demonstrate luminescence in a wide range of visible and near-infrared ranges. One of the actively studied inorganic luminescent materials is a group of strontium aluminates as a matrix. The use of strontium aluminates is due to their ability to form a large number of phases of different composition in the SrO – Al2O3 system, which implies a purposeful influence of the matrix composition on the optical parameters of the Bi-activated luminescent materials obtained. Bismuth, in turn, is sensitive to changes in the crystal environment, which means to the composition of the matrix, crystal structure, positions occupied, defects, etc. In this regard, it is important to have a detailed understanding of the influence of the structure and composition features on the optical properties of the resulting compounds.
This work presents detailed studies of the crystal structure and optical properties of strontium aluminate samples obtained by solid-phase synthesis. Using X-ray diffraction and Raman spectroscopy, the phase composition and features of the crystal structures of the synthesized compounds were studied: for a series of samples with different ratios of the initial components SrNO3/Al2O3 and activator types - Bi2O4 or Bi2O3. The main parameters of crystal structures, the average values of bond lengths were also obtained and assumptions were made about the positions possibly occupied by bismuth in the synthesized matrix.
In addition, the luminescent properties of strontium aluminates activated by bismuth oxides were studied. From the obtained spectra of the studied samples, two-dimensional maps of the dependence of the glow on different pumping frequencies were formed. A 3D scanning of the sample was carried out using a confocal microscope, which allows selectively registering luminescence from a region limited by the size of the diffraction spot.
The work was supported by a grant for young JINR researchers (No. 23-402-07)
A two-step method was used to synthesize the LiNi0.8Mn0.1Co0.1O2 (NMC811) and copper (Cu)-doped NMC811 (Cu-NMC811) cathode materials, the co-precipitation and solid-state synthesis. The effect of Cu doping on the structure, morphology and electrochemical performance of NMC811 nanopowders was investigated. The thermogravimetric analysis confirmed that the annealing temperatures around 850 ℃ are required to form NMC811 nanopowders. The X-ray diffraction patterns of both NMC811 and Cu-NMC811 corresponded to hexagonal α-NaFeO2 structure with R-3 ̅m space group. X-ray photoelectron spectroscopy showed oxidation states on the surface of the nanopowders. The Scanning electron microscopy shows the morphology of polyhedron-like NMC811 particles changes to uniformly distributed rock-like particles under Cu doping. Fourier-transform infrared spectroscopy displayed vibration bands belonging to NMC811 unaltered by doping Cu. The electrochemical performance of Cu doped into NMC811 improved the initial discharge capacity to 287 mAhg-1 at 0.1 C and the structural stability. The results further showed better capacity retention of 56.09% after 100 cycles for Cu-NMC811.
Lithium-ion rechargeable batteries, in particular the cathode materials, are now more essential than ever before as improved, reliable, and effective energy storage systems. Lithium cobalt oxide (LCO), the cathode material now in use, has a reputation for being toxic, expensive, and cobalt-scarce. Due to their accessibility, affordability, and non-toxicity, Nickel Manganese Cobalt (NMC) has been suggested as an alternative cathode material for lithium-ion batteries. In addition, due to their high capacity and improved structural stability, lithium, and manganese-rich composites LiMnNiO2 have gained a lot of interest as potential cathode materials for Li-ion batteries.
In this study, we employed experimental and computational modelling techniques to investigate the stability of manganese nickel oxide LiMn1.5Ni0.5O2 system. The heats of formations indicated that the structure is thermodynamically stable. The results of the lattice parameters, elastic properties and x-ray diffraction agreed with computational and experimental data. A cluster expansion technique generated new thermodynamically stable phases of LiMn1.5Ni0.5O2 system doped with Co and F which could be used for future battery developments.
Keywords: Computational, Doping, Experimental, Structural Properties, Stability.
Polymer brushes represent a class of surface coatings consisting of macromolecules attached to a surface. This class of structures owns unique features such as elongated conformation of polymer chains, possibility to polymer modification and so on, so that they can be utilized in various fields of science and industry. For instance, polymer brushes are used as efficient lubricants with ultralow friction, smart coatings responsive to external triggers, protective coatings, etc. Also polymer brushes are actively used in specific polymer passivation of chemically inert surfaces for single-molecule studies.
There are several strategies for the solution synthesis of polymer brushes which have their advantages and limitations: widely applied and well investigated “grafting to” approach, consisting in the chemisorption of functionalized polymer chains to the target groups on the surface, and in some sense opposite “grafting from” approach, based on a controllable linear growth of polymer chains from the surface. The intermediate “grafting through” approach, in which the surface itself takes part in polymerization reaction due to deposited on the surface reactive groups, has attracted an increasing interest in recent years. “Grafting through” may be treated as a combination of the “grafting to” and “grafting from” approaches, so this approach partially inherits the advantages of both “grafting to” (simplicity) and “grafting from” (relatively high grafting density, variability of the synthesis components, relatively low cost) approaches. “Grafting through” technique has already proved itself in the field of nanocomposites and it has a great potential in the other areas of application. However, processes that occurs in the “grafting through” system as polymer brush grows are not well known, as most of the efforts during the last decades were targeted at “grafting to” and “grafting from” approaches, so this work is an attempt to reveal new knowledge about this technique.
The objective of our study is the analysis of the structure, quality of the polymer film and its chemical composition. The brushes were synthesized in three steps: surface activation, surface modification by grafting the anchor monomers, and attachment of the growing polymer chains to the surface. Chemical composition of such layers at each step of preparation was proved by X-ray photoelectron spectroscopy and fourier-transform infrared spectroscopy and their morphology was analyzed by atomic-force microscopy. It was shown that the thicknesses of the dried brush obtained with the method of X-ray reflectometry can be tuned by varying the polymerization temperature, since it affects the length of macromolecules. The scaling dependence of the brush thickness on the polymer length was obtained by the comparison of the sizes of attached and free polymer chains, which corresponds to an intermediate grafting density between a mushroom-like or a fully stretched polymer brush. Increasing of the polymer molecular weight does not result in a significant decrease of the grafting density, estimated from molecular masses of attached polymer chains. The long-term exposure of modified surfaces to water demonstrated that they are more stable than similar coatings not covalently attached to the substrate.
Acknowledgements. The work is financially supported by the Russian Science Foundation (project № 21-73-10197). XPS measurements were provided by Research Center for Collective Use "Nanochemistry and Atmospheric Chemistry" (Faculty of Chemistry, MSU).
The Hong-Ou-Mendel effect (HOM effect) was discovered and experimentally demonstrated by Hong et al. in 1987 [1] and theoretically described in [2]. In this paper, we will consider its implementation on a linear beam splitter consisting of a substrate and two waveguides on it, closely converging in the center, with two input and output ports, and with detectors at each output port. The essence of the effect under consideration is that two identical single-photon waves fall on the beam splitter in a ratio of 1:1 (with reflection coefficients R and transmittance T close to 1/2), one for each input port. When photons are identical, they cancel each other out. The HOM effect often takes place both in fundamental works on quantum mechanics and in practical implementations of quantum technologies [3]. A simple theoretical explanation of the HOM effect has been found based on the constant coefficients R and T and the statistical distribution of bosonic photons [4, 5]. In this interpretation, we are not interested in what happens to the incident photons in the beam splitter. To do this, we consider lossless with constant coefficients R and T (i.e., "ordinary" beam splitters), and the beam splitter is the source of two other photons, subject to bosonic statistics. Choosing the values of the coefficients R = T = 1/2 and substituting them into the expression for the wave function of photons at the output ports of the beam splitter from [4], it turns out that in this case the photons come out in pairs, i.e. the probability will be P = 1/2 for each of the detectors, which contradicts the classical idea of the separation of two beams of light with coefficients R = T = 1/2. In the classical representation, at R = T = 1/2, there can be 4 options: 1. the first and second photons hit detectors 1 and 2, respectively; 2. the first and second photons hit detectors 2 and 1, respectively; 3. the first and second photons hit detector 1; 4. The first and second photons hit detector 2.
As a result, there are 4 equally probable events, which obviously gives the probability P = 1/4 for each of them. This phenomenon is called the HOM effect and is a good way to test the quantum properties of not only photons but other particles as well. In other words, in the HOM effect, the probability of photons hitting the first detector, and for the second detector P1,2 = (R − T )2, with equal R and T will be equal to zero. If we consider non-monochromatic photons [6,7], but identical (frequency-dependent beam splitters), then choosing R = T = 1/2, we take into account frequency-dependent fluctuations of the beam splitter coefficients, which were not previously taken into account. Here we consider cases for different practical applications of the proposed theory in the case of different frequency-dependent functions. These issues will be discussed in detail in this work.
The work was supported by Russian Science Foundation grant № 20-72-10151.
[1] Hong, C. K., Ou, Z. Y. & Mandel, L. Measurement of subpicosecond time intervals between two photons by interference. Phys. Rev. Lett. 59, 2044–2046 (1987).
[2] F. Salvat, J. D. Martinez, R. Mayol, and J. Parellada Phys. Rev. A 36 (2), 467-474 (1987)
[3] C. K. Hong, , Z. Y. Ou, and , L. Mandel Phys. Rev. Lett. 59, 2044–2046 (1987).
[4] Z.-Y. Ou 2007 Multi-Photon Quantum Interference (New York: Springer).
[5] A. Politi, M. J. Cryan, J. G. Rarity, S. Yu, and J. L. O’Brien Sience 320, 646–649 (2008).
[6] D. N. Makarov Optics Letters 45, 6322–6325 (2020).
[7] D. N. Makarov Scientific Reports 10, 20124 (2020).
The large energy and momentum transfer of ordinary muon capture makes it an excellent tool to study the nuclear structure at conditions similar to neutrinoless double beta decay and benchmark the corresponding nuclear matrix elements. The MONUMENT collaboration is performing a set of muon capture experiments at the Paul Scherrer Institute in Switzerland. In the report, the measurement principle, the setup and preliminary results performed with Ba-136 target are presented. These measurements will benefit future calculations for leading double beta decay experiments.
The Isotope Mass Separator On-Line Device (ISOLDE), is an experimental setup at CERN is dedicated to the topical theme: β-decay kinetics spectroscopy studies for research into nuclear structure, nuclear engineering, and astrophysics. UWC has a leading experiment approved at IDS. To investigate nuclear shape coexistence in 80,82Sr nuclei
with the beta decay of 80,82Y. The study aims at measuring internal conversion electrons using the SPEDE electron spectrometer, branching ratios with four germanium clover detectors, and lifetimes with two LaBr3(Ce) detectors. These measurements will complement our investigations of shape effects in 80,82Sr using safe multi-step Coulomb excitation measurements carried out at TRIUMF. The new Modern African Nuclear Detector Laboratory (MANDELA) at the University of the Western Cape is equipped with a double photon counting setup using NaI(Tl) scintillation detectors and a 250-MHz Pixie-16 digitizer from XIA. This digitizer is similar to the 100-MHz Pixie-16 digitizers in use at IDS. The technical description of the pixie-16 spectrometer card device is
presented in this work along with the γ-γ experimental demonstration using the double photon counting setup with NaI(Tl) scintillation detectors arranged in symmetrical rings placed relative to the radioactive Co-60 source, which is coupled to the interrogated PMT base. Data is acquired using the acquisition code POLL2, which is also
responsible for readout and visualization of the Pixie-16 list-mode experimental data, it is regarded as the main DAQ program composed of a user-friendly environment for functions and command-lines interface (CLI), which uses text command threads with a devised method for entering them that enables the users to directly enter commands in the ROOT terminal to be performed by the centOS7 operating system, which is
composed of an advanced graphical user-friendly interface (GUI Linux) to help users monitor and debug the detection system in either real-time or off-line mode to establish data acquisition, spectral analysis, and optimization of digital parameters to further toggle the channel and module digital parameters embedded in the paass-lc package.
The off-line mode event reconstruction is tackled so as to obtain correction values of resolution offsets of scintillator detectors by optimizing extrinsic properties of resolution degradation artifacts such as defects in signal fidelity with pulse shape analysis model
prior. In list mode, the energy and time for each event are stored in a runfile (e.g., run00 .ldf). These .ldf formart files should be in the same folder where the data is acquired. Results such as single energy distributions and typical prompt γ-γ matrix spectra are acquired. Results in preparation of our new experiment at CERN, will be presented and
their implications discussed.
The read-out electronics of the mRPC(multi-gap Resistive Plate Chambers) detectors of the NA61/SHINE experiment at CERN are based on the DRS4 (Domino Ring Sampler 4) chips. One of the main challenges of using these chips is to distinguish signals from noises due to their complex waveforms. FFT(Fast Fourier Transform) based algorithm was developed and already used to analyze DRS4 data collected during the tests of mRPC with the positron beam at the "PAKHRA" accelerator (LPI RAS Troitsk). The new ML(Machine Learning) based algorithm was developed and used to test the same data. The fastest elapsed time and the same performance as FFT has been achieved. Such a high performance of the ML-based algorithm gives the possibility to filter noises during real-time data-taking of the experiment.
Because of their unique feature, ultracold neutrons (UCN) are used as a sensitive instrument in fundamental physics experiments where high-precision measurements are required. Various UCN measurements are especially aimed at solving unanswered questions in fundamental physics, astrophysics and cosmology. These include the verification of fundamental theories, such as the search for the electric dipole moment of the neutron, the measurement of the neutron lifetime and the search for new types of interactions at short distances, the search for neutron-antineutron oscillations, etc.
However, the solution of these problems is limited by the intensity of the UCN source, so the development and construction of a high-intensity UCN source is extremely important, which will make measurements more comprehensive and minimize statistical errors. In this regard, it is proposed to develop high-intensity UCN source in the thermal column of the WWR-K research reactor.
The thermal column of the 6 MW WWR-K reactor is available for construction of the UCN source with record UCN density for fundamental studies. The large diameter (1 meter) of the thermal column makes it possible to place a lead shield 10 cm thick to reduce the heat load; room temperature graphite will moderate neutrons to thermal energy range; 19 K low-temperature converter will produce cold neutrons, and superfluid helium at a temperature of 0.8–1.25 K will convert cold neutrons into ultracold neutrons. The estimated volume density of UCN in the source chamber of 35 l is about 1.6*10^5 n/cm^3 at a helium temperature of 0.8 K, which is more than 1000 times higher than the maximum achievable UCN density at the ILL source.
Parametric X-ray radiation (PXR) is a consequence of the interaction of charged particles with a substance in which there is a periodic structure. This type of radiation is generated as a result of coherent emission of electrons of the medium due to polarization caused by the Coulomb field of incident charged particles. The characteristics of such radiation depend on the incident charged particles, the angle of observation, as well as on the characteristics of the sample under study [1]. Previously, a lot of work was carried out on the generation of PXR from crystals and polycrystals, and our group was able to register PXR from powder targets for the first time. The advantage of powder targets lies in the absence of preferential orientation of crystallites, which distinguishes them from polycrystals. In the first work on the study of PXR from powders, tungsten powder with a grain size from 0.8 to 1.7 microns was used as a target [2]. The experimental results showed a good agreement with the kinematic theory of PXR. In this regard, it was decided to continue research with powders.
This paper shows the results of continuing studies of PXR generation from powders. Nickel powder with a grain size of 1.56 microns was selected as the test sample. The experimental part was carried out in the Department of High Energy Physics of the FIAN. The source of relativistic electrons was a microtron with an energy of 7 MeV, the observation angles were 150 degrees and 180 degrees relative to the velocity of the electrons. The results obtained showed a good agreement with the kinematic theory of PXR in form, position and relative intensity for the selected observation angles.
[1] Feinberg, Ya. B. On parametric X-ray emission of fast charged particles in periodic media / Ya. B. Feinberg, N. A. Khizhnyak // JETF. -1957. – Vol.32, No.4. – pp. 883-885.
[2] Alekseev, V. I. Parametric X-ray radiation from powders / V. I. Alekseev, A. N. Eliseyev, E. Irribarra, et al. // Physics Letters A. – 2019. – V. 383. – P. 770– 773.
Analyses performed on data from high energy experiments aim to describe the nature of processes ruling high energy collisions and compare the results with theoretical predictions. To ensure reproducibility of results and reliable comparisons between different experiments, a common representation is needed where the real values of observables are determined with the least possible uncertainty. Such representation is often achieved by performing the unfolding of distributions obtained from experimental data using previous knowledge from Monte Carlo(MC) event generation and detector simulations. One of the most popular methods for unfolding is the Iterative Bayesian Unfolding (IBU) which uses prior weights to iterative improve the accuracy of “true” spectra. Along with corrections for detector effects, efficiency and acceptance corrections are also estimated from MC. Unfolding traditionally considers one binned observable at a time, and only those used later in the analysis, hence leaving out important information about detector effect such as extra observables or the relations between them. A method called OmniFold naturally incorporates information from the full phase space to iteratively reweight MC unbinned data into more realistic values by using machine learning to extract abstract relations from observables. This work exploits the advantages of OnmiFold method to generate an unbinned and unfolded phase space from which to calculate new observables of interest. Many new observables are proposed as more robust against statistical fluctuations and theoretical divergences, such as $\phi^*$ which is fully determined by angular measurements and its uncertainty is reduced at low $p_T$, where perturbative quantum chromo dynamics fails to accurately describe experimental data.
Centrality determination is an important task because it allows estimating the collision system size in relativistic heavy-ion collisions. With the help of centrality, it is also possible to compare the results of upcoming measurements with the Multi-Purpose Detector (MPD) at NICA with data from other experiments and calculations of theoretical models. In this work is proposed a new approach for centrality determination with
energy of spectators. Centrality determination procedure was tested on NA61/SHINE data for Pb+Pb collisions at p_lab = 13A GeV/c.
The space-time picture of hadron formation in high-energy collisions with nuclear targets is still poorly known. The tests of hadron formation was suggested for the first stage of SPD running. They will require measuring charged pion and proton spectra with the precision better than $10\%$. A research has been carried out to check feasibility of such studies at SPD. In this work, $^{12}C-{^{12}C}$ and $^{40}Ca-{^{40}Ca}$ heavy ion collisions at center of mass energy of 11 GeV/nucleon were simulated using the SMASH event generator. Firstly, the generator-level events were studied. The distribution of track multiplicities and momentum distributions of different types of charged particles were obtained. Secondly, the generated events passed through the full reconstruction using the SpdRoot framework. At this stage particles were identified using $dE/dx$ measurement and time-of-flight information. It allowed us to estimate charge track multiplicities in the tracking system and purities of charge particles spectra. The results on multiplicity are important to estimate occupancies in the tracking system, while the results on the pion and proton momentum spectra show that particle identification should be acceptable for validation of hadron formation models. This is the first study of moderate ion collisions for the SPD Collaboration.
The direct photon production in proton-proton collisions, both inclusive and heavy-meson-associated, is an important source of information on gluon distribution function inside the proton. Through the studies of transverse single-spin and double longitudinal asymmetries in polarized-beam collisions one can extract the information of the spin gluon content [1,2]. Since the study of direct photon production is one of the important tasks of the physical program at Spin Physics Detector (SPD) at NICA Collider [3] one faces a problem to recognize the direct photons from the background. Primary decay photons from pi0 would be a main source of the background to direct photons at NICA energies of sqrt S = 27 GeV and sqrt S = 20 GeV.
At first step in our work we study the set of existing data in pp colisions at energies from19.4 GeV to 630 GeV on direct photon and pi0 inclusive production. We calculate the inclusive neutral pion and photon production diferential cross sections in the leading order of Particle Reggeization Approach [4] to extract the NLO to LO K-factors. Then we simulate these spectra using Pythia8 to obtain photon-to-neutral pion ratios.
At the next step we simulate the spectra of decay photon candidates at NICA energies on different kinematic variables to obtain the form of distributions, which allow us to apply a number of cuts to distinguish signal events from pi0 decay background at the generator level. Finally we propose the cuts which increase significantly the signal to background ratio.
[1] Saleev V.A., Shipilova A.V. Double Longitudinal-Spin Asymmetries in Direct Photon Production at NICA // Physics of Particles and Nuclei Letters 2023. — Vol. 20. Issue 3. № 3. — P. 400-403.
[2] Saleev V.A., Shipilova A.V. Gluon Sivers Function in Transverse Single-Spin Asymmetries of Direct Photons at NICA // PHYSICS OF ATOMIC NUCLEI 2022. — Vol. 85. Issue 6. № 6. — P. 737-747.
[3] Arbuzov A., Bacchetta A., Butenschoen M., Celiberto F. G. On the physics potential to study the gluon content of proton and deuteron at NICA SPD // Progress in Particle and Nuclear Physics 2021. – Volume 119. – P.103858.
[4] A. V. Karpishkov and V. A. Saleev Production of three isolated photons in the parton Reggeization approach at high energies // Phys. Rev. D. – Vol. 106. – P. 054036.
The size and evolution of the matter created in a relativistic heavy-ion collision strongly depend on the collision's initial geometry, defined by centrality. Experimentally the centrality of collisions can be characterized by the measured multiplicities of the produced particles at midrapidity or by the energy measured in the forward rapidity region, which is sensitive to the spectator fragments. We will propose the procedure for centrality determination based on Monte-Carlo sampling of spectator fragments. The validity of the procedure has been checked using the fully reconstructed DCM-QGSM-SMM model events and published data from the NA61/SHINE experiment. Also, we will discuss the prospects of using the proposed procedure for centrality determination in the BM@N and MPD experiments at the NICA facility.
This study focuses on the reconstruction of neutrino direction in the Baikal-GVD experiment using convolutional neural networks and graph neural networks. Monte Carlo simulation data is utilized, examining single-cluster events of atmospheric neutrino with energies ranging from 10 GeV to 100 TeV. The performance of proposed models are compared to a standard reconstruction algorithm comparing their median angular resolutions. Results show that neural networks offer enhanced accuracy over the standard algorithm, particularly in small polar angles.
Transitional pion form factor; 1/Nc corrections; nonlocal quark model
The fundamental theory of strong interactions is quantum chromodynamics. In the low-energy area, the strong coupling constant is not a small parameter, so the use of methods that do not use perturbation theory, for example, effective quark models, is required.
One of such models is the nonlocal quark model [1]. The model is based on expansion in terms of the inverse number of quarks (1/Nc). When considering the diagram technique within the framework of the model, it turns out that any meson propagator in the diagrams leads to a suppression coefficient of 1/Nc [2].
A large number of diagrams with 1/Nc corrections leads to the need to automate the calculation process. The following calculation program is currently implemented:
• The initial stage of generating diagrams is carried out in the QGRAF program [3]
• A program was written for processing data generated by QGRAF, where an algorithm for selecting diagrams by 1/Nc-indices was implemented
• Classification of diagrams into certain types has been made
• Subsequently, the expressions are transferred to the FORM analytical calculation program
Using the program, the transition form factor of the pion was considered [4].
The holographic duality relates observables in some $d$-dimensional quantum conformal field theory in a flat spacetime at strong coupling with quantities in a dual classical gravity defined in ($d+1$)-dimensional anti-de Sitter spacetime.
We construct and analyze observables in holographic RG flows for a $3$-dimensional supergravity model with a scalar field and non-trivial potential. In the report we briefly review the procedure of the holographic renormalization, which yields the notion of the holographic RG flow. The holographic RG flow is described by the domain wall solution, which is asymptotically AdS and contains a scalar field with certain boundary conditions imposed. This solution can be interpreted as a deformation of a dual theory either by a relevant operator or a vacuum expectation value (VEV) of the operator. We will find one-point functions for scalar operators and components of stress-energy tensor. Using the perturbation of the metric and scalar field, as well as analysis near the boundary, a two-point correlation function will be obtained.
Masses of the ground and excited states of asymmetric fully heavy tetraquarks with open charm and/or bottom are calculated within the relativistic quark model, based on the quasipotential approach and QCD, and diquark-antidiquark picture of tetraquarks. The relativistic diquark-antidiquark interaction quasipotential takes into account the internal structure of the diquark and all spin-dependent and spin-independent relativistic corrections. It is shown, that there is a significant mixing between the asymmetric in flavor states of tetraquarks with the same total momentum-parity ($J^{P}$), but different full spins of the tetraquark ($S$) within the same excitation. The calculated masses of such tetraquarks are compared with the fall-apart decay thresholds into a pair of heavy mesons. The states that could be observed as narrow resonances are determined.
The first images of black holes have opened up new possibilities for testing extended theories of gravity. In this paper, we propose and develop a method for constructing the background of the shadow of spherically symmetrical non-rotating black holes for the case of $g_{11}\neq - g_{00}^{-1}$. The results of the analysis for the extended theories of gravity are compared with the predictions of the general theory of relativity (GRT) when taking into account the data of the Event Horizon Telescope (the global network of radio telescopes on which the first direct image of the BH was obtained).
After the publication of the article by Alexeyev, Prokopov, and Zenin in J. Exp. Theor. Phys. (2022), the Event Horizon Telescope (EHT) project obtained the first direct image of a black hole in the center of our galaxy, Sagittarius A [The Astrophysical Journal Letters, 930, L17, 2022]. The results obtained in [Alexeyev, Prokopov, and Zenin in J. Exp. Theor. Phys. (2022)] are in full agreement with the results of observations of Sagittarius A and M87 for the following models: the Horndeski model with the Gauss-Bonnet invariant, loop quantum gravity, Bambelby scalar model, Gauss-Bonnet model. In conformal gravity, large values of $m_2$ and $Q_s$ should be excluded. In $f(Q)$ gravity, observations of Sgr A additionally limit the values of the parameter $\alpha$: $-0.025<\alpha<0.005$. For an alternative generalization of the bumblebee metric with the Schwarzschild approximation, the constraint becomes as follows: $-0.05 The idea to extend the existing classical gravity theories with their black hole solutions is extensively developing now. In this way, some theories that were "closed" by GW170817 test obtained new possibilities. For example, the well-known Fab Four model was saved in such a manner not so long ago. The same method was also used to extend the black hole solution in $R+R^2$ gravity model [Phys. Rev. D 100, 086010 – Published 14 October 2019]. So, a new solution was obtained. Based on the ideas of black hole's shadows modeling and the latest Event Horizon Telescope results, it seems interesting to test the accuracy of experimental predictions for the "improved" models based on such a solution in $R+R^2$ gravity. Here, it is important to note that both black holes whose images were taken by the Event Horizon Telescope are spinning, so the first step is to obtain the spinning version of the solution [Xavier Calmet, Roberto Casadio, Folkert, "Quantum gravitational corrections to a star metric and the black hole limit," Phys. Rev. D 100, 086010, published on 14 October 2019].
The report presents a brief overview of the family of methods for numerical solution of a non-stationary Schrödinger equation, based on an application of the Lee-Trotter-Suzuki product formula to an approximation of the evolution operator. A way for optimizing high-order accuracy circuits is presented. The application of the Lee-Trotter-Suzuki method to solving some non-stationary problems is demonstrated.
Nowadays, General Relativity is the generally accepted gravitational theory. However, there are some issues, which cannot be explained within the framework of modern physics, such as dark energy, dark matter, inflation etc. One of the ways to solve these problems is to modify gravity. f(R)-gravity is among the simplest ways to modify gravity. Unfortunately, f(R) - theories without screening mechanisms have some problems with describing observational data. One of the most elegant and effective solutions to these problems is hybrid metric-Palatini f(R)-gravity. This theory successfully describes observational effects in the solar system, double systems with pulsars, cosmological dynamics, etc.
But in order to become generally accepted, such a gravitational theory must explain everything the same as general relativity can explain. The goal of this work was to test the possibility of describing accretion in hybrid f(R)-gravity. For this purpose, accretion onto a spherically symmetric black hole in Thorne-Novikov model in case of hybrid f(R)-gravity was considered. In this work we numerically calculated the energy flux, temperature distribution, emission spectrum and energy conversion efficiency of accretion disks.
Didenko E.A.1,2, Doroshkevich A.S.2,3, Samedovaa U. F. 2,4, Kirillov A.K.1, Vasilenko Т.А.5, Oksengendler B.L.6,7, Nikiforova N.N.6,7, Balasoui M.2,8
1Dubna StateUniversity, Dubna, Russia, 19 Universitetskayastreet, Dubna, Moscowregion,141982
2JointInstituteforNuclearResearch, Dubna, Russia
3Donetsk Institute for Physics and Engineering named after O.O. Galkin, Kiev, Ukraine
4Institute of Physics, National Academy of Sciences of Azerbaijan, pr. Dzhavida 33, Baku, AZ1143 Republic of Azerbaija
5Saint-Petersburg Mining University, St.-Petersburg, Russia
6Institute of Materials Science, Academy of Sciences of the Republic of Uzbekistan, Tashkent, 100084 Uzbekistan;
7Institute of Physics and Technology, Ural Federal University, Yekaterinburg, 620078, Russia;
8Horia Hulubei National Institute for R&D in Physics and Nuclear Engineering (IFIN-HH), Bucharest Romania
At the present time, the problem of renewable energy sources is relevant due to the depletion of traditional energy resources. In this aspect, a lot of work has been done in the field of developing converters into an electric form of solar energy. New devices are being developed, which are based on new physical principles. In particular, encouraging results have been obtained in the field of adsorption electric power engineering. In particular, the devices capable of converting the chemical energy of adsorption of atmospheric moisture molecules into an electrical form were developed [1-3]. The relevant scientific and technological task is the development of power plants capable of producing electrical energy from some renewable sources (hybrid) in particular, sunlight energy and moisture adsorption energy. This function can be performed by nanoporous photoadsorbers as FeSe-CuInSe2 and MnSe-CuInSe2 - systems. Such structural organization (2d in 3d) allows obtaining electricity through two physical channels: photogeneration (3d properties) and chemoconversion (2d properties). The studying of the electrical properties of nanostructured crystals FeSe-CuInSe2 and MnSe-CuInSe2 at direct current is a relevant and was a purpose of this work.
Crystals of two compositions were used as the studied objects: 10mol% MnSe-90mol%CuInSe2 and 5mol%FuSe-95mol%CuInSe2 obtained using chemical technology. Voltammograms (V-I) were obtained in the linear scan mode by the R-20 device ("Elinns") in the moisture saturation mode at three points (75, 35 and 26% ± 5%). The sample chamber was a closed 350 ml container with controlled atmospheric humidity using MgCl2×6H2O (35%) and NaCl (75%) salts.
A significant dependence of the electrical parameters on humidity on the illumination of the samples was established. A new size effect of an abrupt change a current at a voltage of the order of 2V has been established (commution [4]). The effect can be interpreted from the standpoint of synergetics.
It is assumed that the observed features of the behavior of the studied systems in humidification and lighting conditions are due to the bimodal structure of the sample. Large single crystals are effective photo adsorbers, and nanopores are physicochemical proton reactors. It was found that an increase in humidity over 35% leads to the appearance of nonlinear sections of the V-I. The established effects can find application in advanced energy engineering and nanoelectronics.
Acknowledgments. The study was performed in the scope of the Serbia - JINR cooperation Projects № 373 2023 items 4 and 5, Belarus - JINR cooperation Projects № 308 items 21 and 22.
[1] A.S. Doroshkevich, and al. // Applied Nanoscience. 9(8), 1603-1609 DOI
10.1007/s13204-019-00979-6
[2] Yuriy Yu. Bacherikov and al. //J Mater Sci: Mater Electron (2022) 33:2753–2764 https://doi.org/10.1007/s10854-021-07481-2
[3] Danilenko Igor and al. // JOURNAL OF MATERIALS SCIENCE. https://doi.org/10.1007/s10853-021-06657-9
[4] Аксютин В. Переходные процессы в электрических цепях. – Litres, 2022.
The interaction between magnetic fields and superconductors reveals a wide range of intricate phenomena. Superconductors, known for their magnetic properties, can be categorized into two primary types based on their response to an externally applied magnetic field. Type I superconductors completely expel the magnetic field, while type II superconductors allow it to penetrate, resulting in a mixed state. In this mixed state, the magnetic flux enters the superconductor as Abrikosov vortices, each carrying one flux quantum. These vortices exhibit repulsive interactions and tend to form a regular lattice pattern.The critical transition between these two types is precisely defined by the Ginzburg-Landau theory, which yields $\kappa = 1/√2$ as the critical value at which the transition occurs
Intriguingly, investigations on materials possessing a $\kappa$ value close to one have uncovered a group of superconductors that do not easily fit into the traditional classifications. Empirical findings have demonstrated the presence of an intermediate mixed state (IMS) within these materials. The magnetic field permeates such superconductors, resulting in diverse spatial arrangements of vortices, including the co-existence of Meissner domains, vortex lattice islands, vortex clusters, and chains.
Within this investigation, a convenient microscopic approach based on self-consistent computation of the Bogoliubov-de Gennes and magnetic state equations is employed to reveal various phenomena, such as vortex clustering and the interactions between multiple vortices. In this study, we investigate the transition of the system from type I to type II superconductor, which involves passing through an IMS. Our research reveals that intricate many-body interactions among vortices lead to the emergence of unconventional vortex patterns during this transition. Our work provides insights into the IMS, revealing the rich physics of this class of superconductors.
S.V. Zhurenko1,2, A.A. Gippius1,2, A.V. Tkachev1, A.V. Gunbin1, N. Büttgen3, M. Schaedler3, I. G. Silkin2, I. V. Morozov2, A.S. Moskvin5
1. P.N. Lebedev Physics Institute, 119991, Moscow, Russia
2. Moscow State University, 119991, Moscow, Russia
3. Experimental Physics V, University of Augsburg, 86159, Augsburg, Germany
4. Institute of Natural Sciences and Mathematics, Ural Federal University, 620083, Ekaterinburg, Russia
e-mail: Zhurenko.Sergey@gmail.com
Due to a series of nontrivial electronic, magnetic, and structural properties, transition metal pnictides with a MnP (B31) type structure have garnered significant interest in the scientific community. Helimagnetic ordering has been observed in the CrAs, FeAs, MnP, FeP compounds [1]. The recent discovery of superconductivity at high pressures in CrAs (Tc ~ 2.2 K at 1 GPa), MnP (Tc ~ 1 K at 8 GPa), and isostructural WP at ambient pressure with Tc ~ 0.7 K has sparked a new wave of research on B31 structure compounds.
Initial neutron powder diffraction studies of FeP and FeAs revealed an extremely unusual magnetic structure, which below TN = 120 K and TN = 77 K, respectively, consists of a combination of two helicoids [2, 3]. These incommensurate helicoids propagate along the crystallographic c-axis, with periods of ≈ 5 and 2.67 times the crystal lattice period in the Pnma representation. It was also reported that Fe ions possess weak magnetic moments of 0.4 µB in FeP and approximately 0.5 µB in FeAs. However, a recent comprehensive neutron scattering study [4] has demonstrated a more complex magnetic structure in FeAs, which is challenging to resolve using neutrons due to the low magnetic moment of Fe. For simplicity, the authors characterized the magnetic structure of FeAs as a noncollinear spin density wave (SDW) order with tilted moments in the ab plane. Mössbauer spectroscopy data indicates that the magnetic structure of FeP consists of a single strongly anharmonic helicoid with a temperature-independent anharmonicity parameter m = 0.9. Our NMR spectroscopy investigations on 31P nuclei, both for polycrystalline and single crystal samples, have revealed that the magnetic structure of FeP exhibits a doubled incommensurate helicoids [5, 6].
The present study aims to investigate the influence of isovalent substitution of arsenic for phosphorus on the magnetic structure of FeP. In this paper, we present measurements of 31P field-sweep NMR spectra at several fixed frequencies and zero-field NMR spectra at 4.2 K, performed on a single-phase polycrystalline FeP1-xAsx samples with x = 0.33 and 0.50. In contrast to the parent FeP compound, we observe a pronounced narrowing of the 31P NMR spectra, indicating a decrease in the induced magnetic field values on phosphorus. Moreove, the magnetic field profile on phosphorus is found to be Gaussian, likely indicating a decrease in the symmetry of the magnetic structure and a significant influence of fluctuations in FeP1-xAsx (x = 0.33, 0.50).
1. K. Motizuki, I. Hideaki, T. Itoh, M. Morifuji, Electronic Structure and Magnetism of 3d Transition Metal Pnictides, Springer, Heidelberg, Dordrecht, London, New York, 2009.
2. Selte, Kari; Kjekshus, Arne; Andresen, Arne F. Magnetic Structure and Properties of FeAs. Acta Chemica Scandinavica, 26 (1972), 3101-3113. DOI: 10.3891/acta.chem.scand.26-3101
3. G. P. Felcher, F. A. Smith, D. Bellavance, and A. Wold, Phys. Rev. B 3, 3046 (1971) DOI: 10.1103/PhysRevB.3.3046
4. Rodriguez, E. E., Stock, C., Krycka, K. L., Majkrzak, C. F., Zajdel, P., Kirshenbaum, K., Green, M. A. (2011). Noncollinear spin-density-wave antiferromagnetism in FeAs. Physical Review B, 83(13). doi:10.1103/physrevb.83.134438
5. Gippius, A.A., Zhurenko, S.V., Büttgen, N. et al. NMR Analysis of the Magnetic Structure and Hyperfine Interactions in a FeP Binary Helimagnetic. Phys. Solid State 61, 723–727 (2019). doi:10.1134/S1063783419050081
6. Gippius A.A., Tkachev A.V., Zhurenko S.V., et al. NMR study of magnetic structure and hyperfine interactions in the binary helimagnet FeP. Phys Rev B. Solid State. 102. 214416, (2020). doi:10.1103/PhysRevB.102.214416.
Ternary RNiSb and binary RSb materials with R = Gd, Tb, Dy were investigated in terms of their electronic properties and band structures using density functional theory DFT+U method. This method is used to take into account strong electron correlations in the 4f shell of the rare earth metals. Our calculations showed that the considered ternary RNiSb materials are semiconductors with an indirect band gap of 0.26, 0.21, and 0.21 eV for GdNiSb, TbNiSb, and DyNiSb, respectively. Additional calculations with spin-orbit coupling resulted in the slightly increased value of the band gap in GdNiSb to 0.38 eV. The calculations for the compressed cell of GdNiSb revealed a semiconductor-to-metal transition under pressure accompanied by transformation of the band gap unto a direct one and further overlap of a few bands. In our calculations, the binary RSb compounds with R = Gd, Tb, Dy were found to be semimetals with the hole and electron pockets near high-symmetry points Г and X. Recent optical measurements for GdSb and TbSb confirmed the semimetallic state in these materials. Moreover, the experimental conductivity spectra were found in good agreement with the theoretical interband conductivity spectra obtained from these calculations [Yu.V. Knyazev, Yu.I. Kuz'min, S.T. Baidak, A.V Lukoyanov, Solid State Sci. 136, 107085 (2023)]. The magnetic moment of all considered compounds were shown to be fully determined by magnetic moments of the rare earth elements in agreement with previously published experimental results. The results of our study were published in several scientific articles [S.T. Baidak, A.V Lukoyanov, Materials 16, 242 (2023); S.T. Baidak, A.V. Lukoyanov, Int. J. Mol. Sci. 24, 8778 (2023); R.D. Mukhachev, S.T. Baidak, A.V. Lukoyanov, J. Magn. Magn. Mater. in press].
This study was supported by the grant of Russian Science Foundation No 22-42-02021.
Obtaining proper event collision data from MPD TPC depends on determination of many working parameters. One of them is electrons drift velocity in gas that fills sensitive volume of the TPC. The drift velocity can vary during runs and changes due to environmental conditions like atmospheric pressure and temperature. Laser calibration system into sensitive volume of the TPC will provide data to calculate the drift velocity. This data also can help to correct errors of trigger delay. Implementation of this task should be also quite fast to provide the velocity online for TPC monitoring purposes.
Mass measurement allows to determine the full binding energy of the nucleus - the integral characteristic of all atomic and nuclear forces which is the key for solving the fundamental physics problems, which includes nuclear physics, astrophysics, physics of fundamental interactions and symmetries, neutrino physics. High precision mass spectrometry could solve the problems of proton and neutron shells location in the nucleus (precision ΔM/M~10-6), the study the nuclei deformation phenomena, searching of so-called “halo-nuclei”, the correct description of the heaviest elements formation during astrophysical r- and rp-processes of fast neutron and proton captures respectively (precision ΔM/M~10-7).
For this reason, a new installation for the high precision mass-spectrometry of heaviest nuclei is being built at the Flerov Laboratory of Nuclear Reactions, JINR, Dubna. It will include new target block, gas-filled separator for the reaction products, cryogenic gas-filled ion stopping cell (so-called “Cryocell”), radio-frequency quadrupole transport system and the multi-reflection time-of-flight mass-spectrometer (MR-TOF-MS). This installation could provide mass measurements with the precision of about ΔM/M~10-6. “Cryocell” is one of the most crucial component of the installation. This is a powerful instrument for the fundamental research due to its high conversion coefficient of the fluxes of reaction products with heavy ions at energies 5-10 MeV/nucleon into low energy secondary beam and low extraction time. It could open the possibility to perform mass analysis of short-lived isotopes with the lifetime of 100 ms and more.
Main parameters of the “Cryocell”:
• Length: 300 mm, diameter: 250 mm;
• Operating temperature: 40 K;
• Gas pressure at operating temperature: 5-7 mbar;
• Gas flow through the cell: ~1 Torr/ls;
• Stopping efficiency for ions: ≥70%;
• Extraction efficiency: ~30%;
• Extraction time: ~30-40 ms.
The “Cryocell” operates at the cryogenic temperatures of about 40 K and filled with extra-pure helium gas with the constant flow through it of about ~1 Torr/ls to avoid appearance of stable compound formation of ions with the atoms and molecules of additional mixtures. The tests of the cryogenic and electrode systems were performed already with success. The experiments of the residual gas analysis were also carried out and showed the full suppression of air components except hydrogen and neon at the temperature of 40 K. In the nearest plans is to perform a complex test with using of the internal source to determine the extraction efficiency, time and overall parameters. In this speech, a status of “Cryocell” will be revealed.
Reconstruction methods using combined kinematic and geometric constraints are useful in recovering semi-leptonic decay channels, where otherwise - due to the missing neutrino, the physically useful kinematic information would be lost. We use the "Sliding Vertex" method, applied to the D0 --> K- l+ nu_l channels. The M_nu_l invariant mass is studied in view of the attainable resolution, as this contains physics information of interest on heavy quark (non-relativistic) dynamics.
The possibilities of a xenon gamma-ray spectrometer [1] for the evaluation and detection of radioactive isotopes and 60Co in particular were studied in this paper. The methods of the most accurate restoration of the activity of the alleged source were also tested in order to reduce the discrepancies of the actual values of the source activity. The detector used in the experiments is an ionization chamber with a volume of 2 liters filled with highly purified xenon. The longest measurements of spectrometric characteristics of previous version of the spectrometer called “XENIA” were performed at the “MIR” orbital station [2].
The activity of the source and the number of registered particles were selected as the main characteristics for consideration. This choice is due to the fact that, knowing the particle flow and knowing the activity, you can quickly estimate the distance to the source. Having info about source activity it becomes possible quickly estimate other dosimetric characteristics.
[1] High Pressure Xenon Gamma-Spectrometers with High Energy Resolution / V.V. Dmitrenko, V.M. Gratchev, S.E. Ulin et al.// Nuclear Science Symposium, 1996. Conference Record. – 1996. – Vol. 1. – P. 393 – 397. DOI:10.1109/NSSMIC.1996.591006
[2] S. E. Ulin, K. F. Vlasik, A. M. Galper, et al., In: Proc. SPIE 3114, 499 (2017). DOI: 10.25283/2587-9707-2022-2-56-67
In this paper, the production and spectroscopic investigation of Mercury and Radon isotopes was performed using complete fusion reactions neutron evaporation residues and multi-nucleon transfer reaction at the mass-separator MASHA. The MASHA setup is installed on the beam line of Cyclotron U-400M at Flerov Laboratory of Nuclear Reactions (FLNR) in Joint Institute for Nuclear Research (JINR), Dubna, Russia. The isotopes produced in complete fusion reactions $^{148}Sm(^{40}Ar,xn)^{188-x}Hg$, $^{166}Er(^{40}Ar,xn)^{206-x}Rn$ and multi-nucleon transfer reaction $^{48}Ca$ + $^{242}Pu$ were passed through the magneto-optical system of MASHA setup with charge state Q=+1 and were separated on the basis of their mass to charge ratio. For the detection of these isotopes, a position sensitive Si detector was used. Further, the experimental data obtained were analysed and spectroscopic investigations were carried out.
Multiple charge state ion beams are of special interest in the fields of atomic physics, material physics and other applications. Electron cyclotron resonance (ECR) ion source can produce high intensity ion beams of high charge state in cw or pulse mode.
For high-voltage applications the problem is the power consumption of devices, and as the room available in the high-voltage terminal of the accelerator is much limited, the ion source should be very compact.
All permanent magnet ECR ion sources have many advantages over traditional ECR ion sources composed of several axial room temperature solenoids and one permanent hexapole magnet, which make them suitable for heavy ion facilities based on high voltage platforms and Van de Graaff Accelerators.
The article presents the results of simulations the magnetic system of the compact 14 GHz ECR Ion source based on permanent magnets for the production of multiply charged ion beams. The magnetic system consists of 7 permanent magnet rings (NdFeB), the size of the system is Ø190×200 mm, that ensures its compactness. For different plasma chamber diameter, the optimal configuration of the magnetic system has been determined to obtain the Binj, Bext and Bmin values in the required range.
The U400 cyclotron complex has been operated in the FLNR, JINR, since 1985. Currently, the complex is being prepared for reconstruction, which includes the modernization of the main nodes of the cyclotron, as well as the creation of a new system for transporting particles through channels leading to two main directions: to the SHELS installation and to the new experimental hall (NEH). In the reconstruction project of the cyclotron U400, it is assumed that beams of charged particles are transported to the TM1 turning magnet, where the particle beam is directed to the NEH with zero rotation, and for transportation to the SHELS installation, the particle beam is rotated by an angle of 40.6 °. The transport of the withdrawn beams to the NEH is carried out after the turning magnet TM1 to the turning magnet TM5, after which the particle beams are sent to physical installations. The elements of the transportation line are the turning magnet TM2, which rotates the beam in the horizontal direction, and the vertical turning magnets TM3 and TM4. This article discusses the results of three-dimensional calculations of TM turning magnets as part of a magnetic system of lines for transporting derived beams of charged particles.
The Electron String Ion Source (ESIS) is a type of ion source, which is under development since 1994, when the electron string phenomenon was first observed. ESIS is a sophisticated modification of Electron Beam Ion Source (EBIS) working in a reflex mode of operation under specific conditions, the operation is based on step-by-step ionization
of the ions by hitting with electrons of an electron string.
The ESIS KRION-6T is designed in order to produce the highly charged heavy ions for
the NICA/MPD project at JINR.
It is a complex facility consisting of several systems: the superconducting solenoid, the
cryogenic and vacuum systems, the electron gun, the electron reflector, the beam drift
structure, the locking system etc. To ensure the operation of these systems a special electronics and control systems developed by the engineers of the ESIS group are used. The topic describes details of designed special electronics.
The problem of erosion of the tungsten lining of the Tokamak reactor vacuum
chamber in contact with thermonuclear plasma is currently of serious interest. This
problem is particularly acute in the area of the Tokamak divertor, where the
greatest threat to the cladding elements is represented by intense pulsed thermal
loads resulting from rapid transients in the hot plasma of the Tokamak. Thus, the
study of tungsten erosion during cyclic pulse heating at a frequency of 10–20 Hz,
with a cumulative number of heating pulses ≥ 10^7, energy densities of ~ 1 MJ/m^2, and a submillisecond duration of the heating pulse, is an actual scientific task. This paper describes an experimental stand based on a frequency-pulse source of an electron beam with an energy of 15-20 keV and a thermionic cathode for the study and simulation of a thermal pulsed load on tungsten from the plasma side.
The Electron String Ion Source (ESIS) is type of ion source working in a reflex mode under specific conditions. The operation is based on step-by-step ionization of the ions by hitting with electrons of an electron string.
ESIS is a complex facility and ion trap control system is it's important part. It affects ion beam formation process and transfer to HILAC. The version, which is under operation now is based on resistance divider. The new system is based on independent modules and could make operation process more flexible.
The topic describes development of the ESIS ion trap control system electronics, it's modifications and operation process.
In September of last year 2021, two groups of perovskite samples of different natures (KNN and PZT:Gd) were sent from the Institute of Materials Science and Technology (IMRE) of the University of Havana, Cuba, to be studied in the Frank Laboratory of Neutron Physics (FNLP). The promising results obtained with these samples allowed the opening of a broad scientific collaboration between both institutions, which focuses fundamentally on the analysis of materials through different characterization techniques. Within these studies, Ion Beam Analysis (IBA) techniques represent one of the most important characterization tools used. As part of this close collaboration, a significant number of interesting materials have been studied to date, whose variety ranges from the study of semiconductor materials, to the compositional analysis of samples of Cuban meteorites. In the present work, the most notable results derived from the study of some of these samples are presented.
The report is dedicated to the development of a compact time-of-flight neutron spectrometer emitted at large angles in the nucleus-target fragmentation region. Neutron detection was performed using stilbene crystals coupled with an assembly of four SensL SiPMs, allowing measurements to be conducted in a strong magnetic field of 0.9 T. The use of the n/g-pulse shape discrimination method is an important feature of the spectrometer, enabling the discrimination of gamma-ray background and the identification of neutron events. The concept of the spectrometer, construction of neutron detectors and data processing methodology are discussed. The report will cover the current status of processing neutron data obtained in Xe+CsI collisions.
The Jiangmen Underground Neutrino Observatory (JUNO) is a cutting-edge
reactor neutrino experiment located in China, consisting of two key detectors: the primary JUNO detector and the auxiliary TAO satellite detector. The TAO detector, a vital component of the experiment, comprises a spherical vessel filled with liquid scintillator and is equipped with approximately 4,000 Silicon Photomultiplier (SiPM) 32-channel arrays.
This presentation focuses on the precise testing and characterization of all SiPM arrays for the TAO experiment. Achieving the experiment's stringent energy resolution goals necessitates SiPMs with outstanding performance characteristics, including high Photon Detection Efficiency (PDE), minimal cross-talk, and low dark count rates (DCR). Additionally, maintaining the SiPMs at the negative temperature of -50 C is essential to meet the required DCR levels.
Our research outlines the setup and methodologies used for the comprehensive characterization of SiPMs across all 4,000 tiles required for the TAO detector. This rigorous testing process ensures that each SiPM array meets the stringent performance criteria crucial for achieving precise energy resolution, approximately 2% at 1 MeV.
The deuteron beam vector polarization was obtained at the Nuclotron Internal Target Station using the proton-proton quasielastic scattering on the polyethylene target at the beam energies of 200, 500, 550, and 650 MeV/nucleon. The selection of useful events was performed using the time and amplitude information from scintillation counters and the position of the target inside the ion tube. The asymmetry on hydrogen was obtained by the subtraction of the carbon background. The polarization values were compared with the data obtained using the deuteron-proton elastic scattering at the beam energy of 135 MeV/nucleon. The polarization of the proton beam, firstly accelerated at Nuclotron, has been measured at 500 MeV.
The study of the high-density equation of state (EOS) and the search for a possible phase transition in dense baryonic matter is the main goal of beam energy scan programs with relativistic heavy ions at energies 2-5 GeV.
In this work, we discuss the layout of the MPD (NICA) experiment in the fixed target mode and the anticipated performance for differential anisotropic flow measurements of identified charged hadrons at energies: 2.3-3.5 GeV.
JINR is developing novate cyclotron for proton therapy (including FLASH) for new JINR's international biomedical research center. The project is about to be put into manufacturing stage. As unavoidable parts of this process, engineering, mechanical and production limitations impose correction on the physical conceptual design of the cyclotron. Therefore, the initial extraction system should be adjusted accordingly to the new model and improved as possible for upcoming manufacturing stage.
MSC230 extraction system is electrostatic deflector followed by two magnetic channels with their compensators. The extraction system adaptation - the procedures, the results, the improvements, the created codes and methods – are described in this talk.
Today, when developing and creating new accelerators of charged particles and heavy ions, various engineering and technological solutions are used in this area. The most important part of almost all accelerator complexes is the beam monitoring and diagnostics system. This work presents a system for monitoring charged particles and heavy ions, allowing operation in a wide range of energies of accelerated particles. The system allows you to visualize the profile of a beam of protons, deuterons, alpha particles, as well as heavy ions of various energies to determine the position and shape of the beam. The operating principle of the system is based on the use of the effect of secondary electron emission. The system consists of a scanning grid of gold-plated tungsten sensors located inside the accelerator ion guide. The beam particles interact with the sensors and knock out secondary electrons. As a result, each sensor becomes a current generator, and the current is proportional to the beam intensity. By measuring the signal at each sensor, it is possible to reconstruct the beam profile and study the processes of secondary electron emission.
This work presents experimental data obtained at the Unique Scientific Installation (UNU) “Cyclotron of the Physicotechnical Institute named after. A.F. Ioffe type U-120" using beams of 40Ar+8 ions with an energy of 53 MeV. The result of the experiments was the visualization of the profiles of beams of protons, alpha particles and 40Ar+8 ions. Studies were carried out of the parameters of signals from the system’s sensors during their interactions with charged particles of the beam. Processing of this information made it possible for the first time to obtain the coefficient of secondary electron emission of 40Ar+8 ions with an energy of 53 MeV during their interaction with the sensor material (tungsten) used in a multi-wire beam monitoring system. This result became the basis for testing the theoretical description of secondary electron emission processes at average energies of charged particles.
In gas phase experiments on the chemistry of superheavy elements at SHE Factory, nuclei recoiled from an irradiated target are separated from the beam and other by-products of nuclear reactions with a physical separator, focused in the focal plane and injected through a thin entrance window into a gas stopping chamber. Recoil nuclei, stopped in a gas mixture, are transported through a capillary by a gas flow to the chromatographic column of the chemical detection setup Cryodetector. Here we report a new compact chamber design developed using finite element analysis in COMSOL Multiphysics for the focal plane of gas-filled separator GRAND at SHE Factory. The defining parameters were image size in the focal plane of the GRAND separator, stopping range of recoil nuclei of Cn and Fl in the separating foil and transport gas, the minimum possible time for recoil nuclei to be flush out from the chamber, the highest possible efficiency of removal of short-lived isotopes of Cn and Fl and inert inner surface of the chamber with respect to volatile elements and compounds.
“Tools based on Python libraries and Jupiter ecosystem for mathematical modeling of Josephson junction”