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Proton flux anisotropy as a function of altitude in the South Atlantic Anomaly is investigated using data from the Compact Environment Anomaly Sensor (CEASE) flown onboard the Tri-Service Experiment-5 (TSX-5) satellite from June 2000 to July 2006. In a 410 km x 1710 km, 69 degree inclination orbit, TSX-5 spanned a broad range of the low Earth orbit regime. Using measurements of total dose, integral energy flux >40 MeV and the differential flux at 40 MeV sorted into 3 degree latitude x 3 degree longitude x 50 km altitide bins and averaged over the entire mission, the components arising from eastward and westward traveling protons have been determined in areas of the SAA where CEASE detection efficiency is not compromised. For the first time, ratios of these components have been compared to predictions of East-West effect models above 400 km. There is good agreement in general with the anisotropy becoming apparent at approximately 1200 km (moving down) and increasing rapidly starting at approximately 1000 km, the magnitude and rate depending on location within the anomaly. Measurements of the differential flux at 40 MeV are compared to predictions of standard radiation belt models as a function of altitude and found to be substantially higher in magnitude than AP8, though a comprehensive survey has not yet been performed. Index Terms--Radiation belts, radiation effects, South Atlantic anomaly.

A proton scattering process resulted in damage to one of the Chandra X-ray telescope's focal plane detectors. In this process, incident protons were transmitted, by scattering off the telescope mirrors, to the focal plane. We identify the proton population responsible for the damage and, using a proper grazing angle formalism, we show that the standard calculations of grazing angle scattering will significantly under predict the expected proton flux at the focal plane. Index Terms--Chandra X-ray telescope CCD radiation damage.

The Compact Environmental Anomaly Sensor (CEASE) is an instrument designed to provide real-time space environment hazard warnings to the host spacecraft. In this paper, we report on the first year of on-orbit operation of this instrument and describe its performance with particular emphasis on its engineering, hazard-warning function. Index Terms--Dosimetry, proton radiation effects, radiation detectors, satellites.