Monte Carlo simulation of induced radioactive background in gamma-ray detector materials

Induced activation in detector materials constitutes a major source of background for spaceborne γ-ray instruments. Future detector systems will utilise a variety of background reduction techniques and novel detector materials to maximise signal-to-noise and resolution of the measurements taken, and assessment of the merits of different designs will require detailed attention to a wide range of physical processes. The Integrated Radiation Transport Suite (IRTS) has been applied to simulate the effects of spacecraft shielding against Van Allen and galactic cosmic-ray protons, the production of secondary hadrons, and induced radioactivity in and the response of γ-ray detector materials. This paper discusses the physics requirements for these simulations, and the degree of success of the models through comparisons with experimental data obtained from Space Shuttle flights and proton-beam irradiation of detector materials