Search

Radioactivity induced in detectors by protons and secondary neutrons limits the sensitivity of spaceborne gamma ray spectrometers. Three dimensional Monte Carlo transport codes have been employed to simulate particle transport of cosmic rays and inner belt protons in various representations of the Gamma Ray Observatory Spacecraft and the Oriented Scintillation Spectrometer Experiment. Results are used to accurately quantify the contributions to the radioactive background, assess shielding options and examine the effect of detector and spacecraft orientation in anisotropic trapped proton fluxes. Space radiation, Gamma ray detectors, Radioactivity, Radiation transport, Sodium iodide, Great Britain.

The considerable investment implicit in large space platforms makes assessment of both their environment and their environmental interactions of utmost importance. In this Report the new factors of relevance to the Polar Platform are reviewed, and environment models and radiation transport codes are employed to assess primary and secondary particle fluxes, dose rates and energy- loss spectra. Monitors are described which can improve the data base. Spacecraft, Great Britain. (JES)

In view of the important influence of background radiation induced by the charged particle environment on the sensitivity of space-borne gamma-ray instrumentation, an extensive series of simulations has been performed on representations of hte Oriented Scintillation Spectrometer Experiment and Gamma Ray Observatory Spacecraft. Previously reported results on shielding are summarized and new results are presented on the influence of detector and spacecraft orientation within anisotropic trapped proton distributions. For the cosmic ray calculation, confidence is obtained by comparison with background observations obtained during a balloon flight of a single detector unit over Alice Springs. Keywords: Great Britain; Space radiation; Gamma-ray detectors; Radioactivity; Radiation transport; Sodium iodide.

Regular flights of a Cosmic Radiation Environment Monitor on-board Supersonic Transport enable mapping of the atmospheric environment to 60000 ft. Results show the importance of secondary particles produced by nuclear reactions in the atmosphere. Single event upsets, Atmospheric neutrons, Great Britain, Cosmic rays, Cosmic Radiation Effects and Action Monitor(CREAM), Microelectronics, Supersonic transport.