Beam test characterisation of a Plastic Scintillator Prototype for the space-based cosmic ray experiment HERD

The High Energy cosmic-Radiation Detector (HERD) facility is planned to go
onboard China's Space Station, planned to be operational starting in around
2025 for about 10 years. The main scientific objectives of HERD are the
search for signals of dark matter annihilation products, precise cosmic
electron/positron spectrum and measurements of anisotropy up to 10 TeV,
precise cosmic ray spectrum and composition measurements up to the knee
energy (1 PeV), and high energy $\gamma$-ray monitoring and survey.
HERD consists of a 3D cubic crystals calorimeter (CALO) surrounded by
microstrip silicon trackers (STKs) and scintillating fiber trackers (FIT)
and by a Plastic Scintillator Detector (PSD) for $\gamma$-ray veto and
ion charge measurement.
A PSD prototype consisting of a scintillator tile readout by two arrays of SiPMs
on opposite sides has been tested with proton and C ion beam at the CNAO
(Centro Nazionale Adroterapia Oncologica) in Pavia, (Italy).
Preliminary results on charge resolution are presented.