Effects of Updated Trapped Radiation Environment on the ISS Dosimetric Measurements

Date

2016-07-10

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Publisher

46th International Conference on Environmental Systems

Abstract

There exist a number of models to define the intensities of the trapped particles. Among the more established trapped models are the historic and popular AE8/AP8, dating back to the 1980s, and the recently released AE9/AP9/SPM. The AE9/AP9/SPM model is a major improvement over the older AE8/AP8 and CRRES models. This model is derived from numerous measurements acquired over four solar cycles dating back to the 1970s, roughly representing 40 years of data collection. In contrast, the older AE8/AP8 was limited to only a few months of measurements taken during the prior solar minima and maxima. The dual goal of this paper is to first validate the AE8/AP8 and AE9/AP9/SPM trapped models against ISS dosimetric measurements for a silicon based detector, to assess the improvements in the AE9/AP9/SPM model as compared to AE8/AP8 model. The validation is done at selected target points within ISS-6A configuration during its passage through the south Atlantic anomaly (SAA). For such validation, only the isotropic spectrum of either model is needed. As a second goal, the isotropic spectra of both trapped models are re-casted into anisotropic spectra by modulating them with a measurement derived angular formalism which is applicable to trapped protons. Since at LEO electrons have minimal exposure contribution, the paper ignores the AE8 and AE9 component of the models and presents the angular validation of AP8 and AP9 against measurements from the ISS DOSMAP measurement campaign (circa 2005). Emphasize is put on validating the anisotropy characteristics of the target points within the crew quarter (CQ) of ISS as the spacecraft transits through the SAA region in ascending and descending nodes.

Description

United States
ODURF
503
ICES503: Radiation Issues for Space Flight
Vienna, Austria
Francis F. Badavi, Old Dominion University, USA

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Keywords

Radiation belts, anisotropy, space station, low Earth orbit

Citation