Beam test results of two shashlyk ECal modules for NICA-MPD

Abstract

Electromagnetic calorimeter (ECal) is an important detector of the Multi Purpose Detector (MPD) at the NICA collider. A shashlyk-type ECal will be constructed for MPD. The particular goals of the MPD ECal are to measure of spatial positions and energy of photons and electrons. The whole ECal consists of 43008 shashlyk tower and each tower consists of 220 layers of 1.5mm scintillator +0.3mm lead plates. 16 Wave Length Shifted fibers are used to collect light signals. The SiPM detector is used to read out the signals. After being amplified, the signal was sent to a waveform sampling circuit to obtain the waveform of each incident particle. Two ECal prototype modules were developed in Tsinghua University and the beam test were carried out at DESY on August of 2018. MPD ROOT is used to analysis the test data.The results show that number of photoelectron (Npe) changes linearly with the electron energy. 4.5% energy resolution, 212.4ps time resolution and 4.7mm spatial resolution are also achieved. All these results show that the prototype of ECal is fully capable of the requirement of the MPD. In this article, the structure of the shashlyk module and its performance in beam test are described.