A low-energy sensitive compact gamma-ray detector based on LaBr₃ and SiPM for GECAM

Abstract

The Gravitational wave high-energy Electromagnetic Counterpart All-sky\nMonitor (GECAM) project is the planned Chinese space telescope for detecting\nthe X and gamma-ray counterpart. It consists of two micro-satellites in low\nearth orbit with the advantages of instantaneous full-sky coverage, low energy\nthreshold down to 6 keV and can be achieved within a short period and small\nbudget. Due to the limitation of size, weight and power consumption of\nmicro-satellites, silicon photomultipliers (SiPMs) are used to replace the\nphotomultiplier tubes (PMTs) to assemble a novel gamma-ray detector. A\nprototype of a SiPM array with LaBr3 crystal is built and tested, and it shows\na high detection efficiency (70% at 5.9 keV) and an acceptable uniformity. The\nlow-energy X-ray of 5.9 keV can be detected by a simply readout circuit, and\nthe energy resolution is 6.5% (FWHM) at 662 keV. The design and performance of\nthe detector are discussed in detail in this paper.\n