Analysis of activation effects in space-borne and proton-beam irradiated γ-ray detectors

The selection of detector materials for space-borne γ-ray systems has previously been based on the response of the scintillator or semiconductor to incident source or background γ-rays, and the practicalities associated with the use of these materials in space. Today the availability of a greater variety of detector materials allows potential optimisation for induced radioactive background as well, which contributes an important source of background for instruments in the space environment. Studies have been conducted on induced activation effects in a variety of γ-ray detector materials of interest for space applications, including BaF₂ and GSO. Results are presented from Space Shuttle and proton-beam (300 MeV and 1 GeV) experiments. Detailed radiation transport computer simulations are used to compare and identify the effects observed in the experimental spectra and, for the space experiments, to quantify the contributions to detector activation from the different sources of radiation experienced in the shuttle cabin