Medium and high energy electron detectors onboard BeiDou navigation satellite in MEO

This work introduces the instruments' design of multi-directional medium-energy electron detector (energy range: 30-770 keV) and high-energy electron detector (energy range: 400 keV to 5.8 MeV) deployed on one of the BeiDou navigation satellites in medium earth orbit. Through the electromagnetic compatibility design, the problem of the detector signal being susceptible to electromagnetic interference is solved and the lower detection limit reaches a very low level of 20 keV. The proton contamination in the electron measurement can be effectively removed by designing the light-blocking layer and the logical working mode of the sensors. The detector circuits and sensor structure are optimized and the miniaturization of the instrument is realized. This study also introduces the calibration method of the detectors, and gives the ground test results, which can provide a basis for the on-orbit calibration and data processing of the instrument.