Activation of space-borne bismuth germanate γ-ray detectors

Results are presented from the Shuttle Activation Monitor flown in the Space Shuttle middeck area on two missions during August 1989 and September 1991. This experiment has been valuable in the study of induced radioactivity in BGO scintillators resulting from bombardment by cosmic-rays, trapped protons, and their secondaries created by interactions in a heavy spacecraft. Data from mono-energetic proton irradiation experiments have allowed investigation of activation effects in BGO for less complicated irradiation conditions, and the results from these experiments are also presented. Detailed simulations of spacecraft shielding and BGO detector activation have also been performed. The output from these compare very well to the experimental data, allowing features in the measured spectra to be identified, and the contributions from the major sources of radiation to be quantified