The performance of the High Energy Particle Detector HEPD-02 on board CSES-02 satellite: from simulation to test beam data

CSES (China Seismo-Electromagnetic Satellite) is a sophisticated multi-payload space observatory aimed to the monitoring of the Van Allen Belts dynamics, the study of solar-terrestrial interactions and the extension at low energies of existing Cosmic Ray measurements. The first satellite (CSES-01) is on orbit since February 2018, hosting on board the HEPD-01 particle detector. The second (CSES-02) will be launched during the early 2024, and will carry HEPD-02, a new high energy particle detector. HEPD-02 is optimized to detect charged particles: mostly electrons (3-100 MeV) and protons (30-200 MeV), with good capabilities in the identification of heavier nuclei. The instrument is quite compact (40.36x53.00x38.15 cm3) and presents important upgrades with respect to its predecessor: it will be the first instrument carrying a CMOS pixel tracker in space, designed to reach a ∼ 4 micron resolution; it will mount an electromagnetic calorimeter that includes six of the largest LYSO crystals ever used in space (15x5x2.5 cm3). The full detector has been recently integrated, with an event reconstruction software already in place. A detailed Monte Carlo (MC) simulation was developed and an extensive beam test campaign performed to validate HEPD-02 capabilities in identification and measurement of kinetic energy and arrival direction of incoming particles. In this contribution a synthetic description of the HEPD-02 detector and its main characteristics will be given. The estimation of its scientific performances on MC simulation will be reported, with a particular focus on their assessment with the different beam test acquisitions and atmospheric muon data.