Calibration Study of the Gamma-Ray Monitor Onboard the SVOM Satellite

The Gamma-Ray Monitor (GRM), which is one of the four main scientific instruments onboard the Space-based multi-band astronomical Variable Objects Monitor (SVOM) satellite, is dedicated to the spectrum measurement and study of Gamma-Ray Bursts (GRBs) in the 15 keV to 5 MeV energy band, as well as to perform real-time triggering and localization of the transient bursts in orbit. In order to fully understand the performance of the developed spectrometer and optimize the calibration scheme for the flight model (FM), several calibration campaigns, such as energy–channel relation and energy resolution, detection efficiency, temperature response, high-voltage effect and the non-uniformity tests of detector crystal, have been implemented during the development phase of the qualification model (QM) of GRM, utilizing radionuclides, hard X-ray beam and synchrotron radiation facility. The data analysis results show good agreement with the expected output by Monte Carlo simulations. The detailed optimization scenario for FM calibration is also presented in this paper.