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CALIBRATION METHODS FOR HALF-SECTORS OF THE MPD/NICA ELECTROMAGNETIC CALORIMETER ON COSMIC RAY MUONS
M.Bhattacharjee(1,3), V.M.Baryshnikov(1),P.A.Bakhtin(5),S.A.Bulychjov(2), B.Dabrowska(1,4), G.E.Fomenko(5), Yu.F.Krechetov(1), V.V. Kulikov(2), M.A. Martemianov(2), M.A. Matsyuk(2), A.Yu.Semenov(1), I.A. Tyapkin(1)
1 Joint Institute for Nuclear Research, Dubna, 141980 Russia
2 National Research Center “Kurchatov Institute”, Moscow, 123182 Russia
3 Gauhati University, Guwahati, Assam 781014, India
4 Plovdiv University Paisii Hilendarski, Plovdiv, Bulgaria
5 National Research Nuclear University MEPhI, Moscow, 115409 Russia
Within the framework of the MPD experiment at NICA [1], a cylindrical electromagnetic calorimeter (ECal) [2-5] with an inner (outer) diameter of 3.45 (4.6) m, a length of 6 m and a weight of 60 tons is under construction. It consists of 38,400 “shashlyk” towers of 64 types, roughly shaped like a truncated pyramid with a base of 4x4 cm2, a height of 40.5 cm and angles between opposite side planes of 0.9 and 1.2 degrees. The ECal implements the so-called projective geometry, when the axes of all towers look at one point of intersection of the heavy-ion collider beams in the center of the cylinder. The ECal is assembled from 50 half-sectors, each containing 768 towers and weighing 1.2 tons. In this report two methods for calibrating the half-sector towers on cosmic muons passing along and across the axes of the towers are discussed. These methods rely on the unique parameters of the readout electronics, which also provide a trigger for the passage of ionizing particles. A peculiarity of the methods is the correction of the tower responses for their spatial orientation. This is implemented by MC simulation in the mpdroot environment. Event selection criteria, parameterization of energy deposition distributions in towers, achievable calibration accuracy, data taking times are analyzed. The two calibration methods are compared both on the simulation data and on the data of the first half-sector measurements. The possibility of applicability of such calibration on a fully assembled ECal is also indicated.
[1] V. Abgaryan et al. (MPD Collaboration) «Status and initial physics performance studies of the MPD experiment at NICA, Eur.Phys.J.A 58 ,7, 140(2022)
[2] A. Yu. Semenov et al. “Electromagnetic Calorimeter for MPD Spectrometer at NICA Collider.” JINST 15 (2020) 05, C05017
[3] V.V. Kulikov et al. “ECAL MPD: geometry and simulation.” JINST 15 (2020) 09, C09017
[4] Y. Li, D. Han, A. Durum et al. “A Shashlyk Electromagnetic calorimeter system for NICA-MPD.” JINST 15 (2020) 11, C11007
[5] Y. Li et al. “Production and quality control of NICA-MPD shashlik electromagnetic calorimeter in Tsinghua University.” JINST 17 (2022) 04, T04005
