The high energy particle detector onboard CSES-02 satellite

In this paper we will present a description of the High Energy Particle Detector (HEPD-02) developed for the China Seismo Electromagnetic Satellite (CSES) project. CSES is a scientific mission dedicated to monitoring electromagnetic, plasma and particles perturbations of atmosphere and inner Van Allen belts caused by solar and terrestrial phenomena, and to the study of the low energy component of the cosmic rays (3 - 100 MeV for electrons and 30 - 200 MeV for protons). The first satellite, launched in 2018, hosted several instruments onboard. The HEPD-01, built by the Italian "Limadou" collaboration, is the instrument devoted to separate electrons and protons, as well as light nuclei in the MeV energy window. The detector is composed of two planes of double-sided silicon microstrip detectors which give the direction of the incident particle, a segmented plastic scintillator for trigger and a calorimeter. The CSES-02 satellite is planned to be launched by the end of 2021. The next generation HEPD foresees improvements both on the tracker and the calorimeter. To improve trigger efficiency a new system with crossed layers of 2 mm thick segmented counters read by light-guides has been designed. A new tracker study is ongoing: 3 planes of ALPIDE CMOS pixel chips, developed for ALICE experiment at LHC.