Performance of LYSO and CeBr3 crystals readout by silicon photomultiplier arrays as compact detectors for space based applications

Space based MeV range gamma rays have been largely unexplored due to the difficulty associated with the measurements; however they address a broad range of astrophysical questions, including indirect searches for dark matter. To address these challenges and yet have compact instruments, the next generation experiments would need detectors with high efficiency, high stopping power, excellent energy resolution, and excellent angular resolution. Fast and bright crystal scintillators coupled to compact photo-detectors are an ideal option. In this work we have investigated the LYSO and CeBr3 crystal scintillators because of their high light yield, fast decay time, and small radiation length. We have used the silicon photomultiplier arrays as photo-detectors because of their small size, simple readout, low voltage operation, and immunity to magnetic fields. We studied the gamma rays response for the 1.6 cm x 1.6 cm x 4.0 cm LYSO crystals and a 1.3 cm x 1.3 cm x 1.3 cm CeBr3 crystal readout by 4 x 4 SensL arrays (ArrayC30035). The crystal self-absorption and timing resolution have been examined along with linearity and energy resolution. The DRS4 evaluation board was used for acquisition of the events.