Using ACIS on the Chandra X-ray Observatory as a particle radiation monitor
Abstract
The Advanced CCD Imaging Spectrometer (ACIS) is one of two focal-plane instruments on the Chandra X-ray Observatory. During initial radiation-belt passes, the exposed ACIS suffered significant radiation damage from trapped soft protons scattering off the x-ray telescope's mirrors. The primary effect of this damage was to increase the charge-transfer inefficiency (CTI) of the ACIS 8 front-illuminated CCDs. Subsequently, the Chandra team implemented procedures to remove the ACIS from the telescope's focus during high-radiation events: planned protection during radiation-belt transits; autonomous protection triggered by an on-board radiation monitor; and manual intervention based upon assessment of space-weather conditions. However, as Chandra's multilayer insulation ages, elevated temperatures have reduced the effectiveness of the on-board radiation monitor for autonomous protection. Here we investigate using the ACIS CCDs themselves as a radiation monitor. We explore the 10-year database to evaluate the CCDs' response to particle radiation and to compare this response with other radiation data and environment models.
Keywords
Cite
@article{arxiv.1007.4185,
title = {Using ACIS on the Chandra X-ray Observatory as a particle radiation monitor},
author = {C. E. Grant and B. LaMarr and M. W. Bautz and S. L. O'Dell},
journal= {arXiv preprint arXiv:1007.4185},
year = {2015}
}
Comments
10 pages, 5 figures. To appear in Proc. SPIE vol. 7732