Characterization of Inorganic Scintillators for the HET/EPD Instrument on board Solar Orbiter

Solar Orbiter is one of the ESA’s missions planned for operating as close to the sun as 0.3 AU. The detection and characterization of the high-energy particles is one of the science requirements of the planned mission. A High-Energy Telescope (HET) has been designed for the Energetic Particle Detector (EPD) Consortium based on an inorganic scintillator crystal and semiconductor detectors. HET will detect electrons from 0.3 - 25 MeV, protons 10 - 100 MeV and heavy ions 50 - 200 MeV/n. The scintillator detector is the heart of the proposed design. Hence, characterization of the different scintillator materials is very important to select a suitable candidate for operating the instrument on the proposed orbit. Here, we will present studies performed on BGO and GSO:Ce including intrinsic radioactivity and temperature dependence of the light yield as well as calibration results in accelerators and quenching by comparison with Monte Carlo simulations.