Design and manufacture of scintillation detector using CsI(Tl) crystal coupled with silicon photomultipliers

Abstract

In this research, a scintillation detector was developed using the CsI(Tl) scintillator crystal coupled with a silicon photomultiplier (SiPM) to replace the photomultiplier tube (PMT), resulting in a compact and energy-efficient detector. A rectangular box-shaped CsI(Tl) scintillation crystal with dimensions of 50x25x25 mm from Kinheng and a SiPM module S13361-3050AE-08 with dimensions of 25x25 mm from Hamamatsu were selected to use. The preamplifier circuit, power supply, and temperature stabiliser have also been integrated into the detector. The characteristics of this detector were evaluated using a 137Cs standard radioactive source together with Ortec’s multichannel analyser device and Gamma Vision software for spectrum analysis. Results showed that the energy resolution for the 137Cs peak of this detector is about 8.03%, which is almost equivalent to the energy resolution of 7.87% of the Canberra detector using 76x76 mm NaI(Tl) crystal coupled to the PMT. The results of the evaluation of stability over time when the operating ambient temperature of this detector with no change showed that the energy peak position and the energy resolution for the 137Cs radioactive source are almost unchanged. The research also investigated the stability of the detector according to the operating ambient temperature. The results exhibited that the output pulse amplitude varies greatly with the ambient temperature, it decreases when the temperature increases and vice versa. Under the condition that the operating ambient temperature varies from 11oC to 50oC, the energy peak position of 137Cs changes were 1762 and 167 channels, respectively in the cases without and with adjustment of output pulse amplitude stabilisation function in power supply for SiPM. When there is a function of output pulse amplitude stabilisation, the change in peak position according to operating ambient temperature is still about 4.3 channels/oC, so further research is needed to correct the influence of ambient temperature on the operation of this detector, to provide wide applicability of scintillation detector using SiPM to replace traditional PMT in the future.