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.
- Publication:
-
Space Telescopes and Instrumentation 2010: Ultraviolet to Gamma Ray
- Pub Date:
- July 2010
- DOI:
- 10.1117/12.857629
- arXiv:
- arXiv:1007.4185
- Bibcode:
- 2010SPIE.7732E..2IG
- Keywords:
-
- Astrophysics - Instrumentation and Methods for Astrophysics
- E-Print:
- 10 pages, 5 figures. To appear in Proc. SPIE vol. 7732