The design and performance of charged particle detector onboard the GECAM mission

Background The Gravitational wave highly energetic Electromagnetic Counterpart All-sky Monitor (GECAM) is dedicated to detecting gravitational wave gamma-ray bursts. It is capable of all-sky monitoring over and discovering gamma-ray bursts and new radiation phenomena. GECAM consists of two microsatellites, each equipped with 8 charged particle detectors (CPDs) and 25 gamma-ray detectors (GRDs). Purpose The CPD is used to measure charged particles in the space environment, monitor energy and flow intensity changes, and identify between gamma-ray bursts and space charged particle events in conjunction with GRD. Methods CPD uses plastic scintillator as the sensitive material for detection, silicon photomultiplier array as the optically readable device, and the inlaid Am-241 radioactive source as the onboard calibration means. Conclusion In this paper, we will present the working principle, physical design, functional implementation and preliminary performance test results of the CPD. As a result, the energy range of electron, gamma-ray detection efficiency and dead time are tested to be better than the indexes required through the ground calibration experiment.