Particle transport simulation for spaceborne, NaI gamma-ray spectrometers

Radioactivity induced in detectors by protons and secondary neutrons limits the sensitivity of spaceborne gamma-ray spectrometers. Three-dimensional Monte Carlo transport codes were used to simulate particle transport of cosmic rays and innerbelt protons in various representations of the Gamma-Ray Observatory Spacecraft and the Oriented Scintillation Spectrometer Experiment. Results are used to quantify accurately the contributions to the radioactive background, assess shielding options, and examine the effects of detector and spacecraft orientation in anisotropic trapped proton fluxes. >