Characterization of the nuclei identification performances of the plastic scintillator detector prototype for the future HERD satellite experiment

Satellite experiments employ plastic scintillators to discriminate charged from neutral particles and to identify charged nuclei. We have assembled and tested a prototype of Plastic Scintillator Detector (PSD) equipped with Silicon Photomultipliers (SiPMs) for the High Energy Cosmic Radiation Detection facility (HERD) that will be installed onboard the future Chinese Space Station (CSS). The HERD experiment will provide high quality data on charged cosmic rays up to PeV energies and gamma rays above 100 MeV energies. In order to explore the capability of charge identification of nuclei up to iron, a beam test campaign was performed in 2022 at CERN to study the overall performance of the PSD. The PSD prototype is composed of 8 plastic scintillator trapezoidal bars of two different lengths. The PSD prototype was irradiated with an ion beam composed of particles of selected momentum of 150 GeV/n at CERN SPS H8 beam line. Along the beam line two 10× 10× 0.5 cm ³ squared plastic scintillator tiles were also placed to monitor the beam composition and the particle fragmentation upstream and downstream the beam line. In this work the main results of the SPS H8 beam test in terms of nuclei identification performances of the PSD ptototype detector will be shown.