Assessing the role of SiPM number on energy resolution in radiation detection using bismuth germanate crystals

Abstract

In this study, we present a simple statistical model to show the relationship between the number of Silicon Photomultipliers (SiPMs) and the energy resolution of the detector. We used bismuth germanate (BGO) crystals in combination with varying numbers of SiPMs to examine the effect of photodetector count on energy resolution. We compared our results with Photomultiplier Tube-based measurements to determine the advantage of SiPMs in terms of energy resolution. We also performed a simulation study with the GEANT4 simulation package to investigate the energy resolution that can be achieved under ideal conditions by using a higher number of SiPMs. The experimental measurements showed that for a photopeak energy of 511 keV, an energy resolution of 29.9% was achieved using five SiPMs covering only 3.25% of the scintillator area, whereas a Photomultiplier Tube (PMT) covering 37% of the same area resulted in an energy resolution of about 23.4%. As a result of the simulation study, it is predicted that the energy resolution can be achieved up to 14.8% for a photopeak energy of 511 keV by using 21 symmetrically distributed SiPM. © 2025 Elsevier Ltd