Study on the Optimized Energy Resolution of Scintillator Detectors Based on SiPMs and LYSO:Ce

Abstract

The cerium-doped lutetium yttrium silicate (LYSO:Ce) crystal has many advantages such as high light output and fast decay time, showing great potential to improve the performance of scintillation detectors. Silicon photomultipliers (SiPMs) are high-performance semiconductor photodetectors, which generally have a higher photon detection efficiency than photomultiplier tubes (PMTs) and are beneficial to realize a better energy resolution. The energy resolution and detected light output of SiPM-coupled LYSO:Ce crystals were studied by optimizing the photon detection efficiency (PDE), the operating voltage, the wrapper, the surface finish and the coupling method between the SiPM and crystal. Considering the output saturation of SiPMs in high light intensity, a preliminary correction method was applied to the saturation response of SiPMs and energy resolution of 662 keV gamma-rays from 137Cs was obtained after correction. The results show that the optimized energy resolution at 662 keV measured by the SiPM of 50 μm microcells can reach 7.6%. The light output of the polished and rough crystal detected by a SiPM of 10 μm microcells were also measured, which can reach 27000 ± 3200 photons/MeV and 36000 ± 3700 photons/MeV, respectively.