  Gamma-Ray Integrated Detectors (GRID) is a student project designed to use
multiple gamma-ray detectors carried by nanosatellites (CubeSat), forming a
full-time and all-sky gamma-ray detection network to monitor the transient
gamma-ray sky in the multi-messenger astronomy era. A compact CubeSat gamma-ray
detector has been designed and implemented for GRID, including its hardware and
firmware. The detector employs four Gd2Al2Ga3O12 : Ce (GAGG:Ce) scintillators
coupled with four silicon photomultiplier (SiPM) arrays to achieve a high
detection efficiency of gamma rays between 10 keV and 2 MeV with low power and
small dimensions. The first detector designed by the undergraduate student team
onboard a commercial CubeSat was launched into a Sun-synchronous orbit on 29
October 2018. The detector has been in a normal observation state and
accumulated data for approximately 1 month after on-orbit functional and
performance tests in 2019.
