  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.
