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Paper: The Temporal Characteristics of the Chandra X-ray Observatory High Energy Particle Background
Volume: 262, The High Energy Universe at Sharp Focus: Chandra Science
Page: 401
Authors: Grant, C. E.; Bautz, M. W.; Virani, S. N.
Abstract: It was observed early on in the Chandra X-ray Observatory mission that the background rates of the Advanced CCD Imaging Spectrometer (ACIS) were highly variable on both short and long timescales. We present results of analysis of lightcurves of the high energy (> 15 keV) ACIS background, spanning most of the mission lifetime. These high energy events are not produced by X-rays, but by the particle background, primarily low and high energy protons. Temporal characteristics of both the quiescent background and background flares will be discussed as well as correlations with Chandra orbital position and the solar activity cycle. The strength and frequency of background flares appear cyclic with a quasi-annual period, most likely from the motion of Chandra's orbit through the geomagnetic environment.
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