Share Email Print
cover

Proceedings Paper

A charge-transfer-inefficiency correction model for the Chandra advanced-CCD imaging spectrometer
Author(s): Catherine E. Grant; Mark W. Bautz; Steven E. Kissel; Beverly LaMarr
Format Member Price Non-Member Price
PDF $14.40 $18.00

Paper Abstract

Soon after launch, the Advanced CCD Imaging Spectrometer (ACIS), one of the focal plane instruments on the Chandra X-ray Observatory, suffered radiation damage from exposure to soft protons during passages through the Earth's radiation belts. The primary effect of the damage was to increase the charge transfer inefficiency (CTI) of the eight front illuminated CCDs by more than two orders of magnitude. The ACIS instrument team is continuing to study the properties of the damage with an emphasis on developing techniques to mitigate CTI and spectral resolution degradation. We will discuss the characteristics of the damage, the detector and the particle background and how they conspire to degrade the instrument performance. We have developed a model for ACIS CTI which can be used to correct each event and regain some of the lost performance. The correction uses a map of the electron trap distribution, a parameterization of the energy dependent charge loss and the fraction of the lost charge re-emitted into the trailing pixel to correct the pixels in the event island. This model has been implemented in the standard Chandra data processing pipeline. Some of the correction algorithm was inspired by the earlier work on ACIS CTI correction by Townsley and collaborators. The details of the CTI model and how each parameter improves performance will be discussed, as well as the limitations and the possibilities for future improvement.

Paper Details

Date Published: 29 September 2004
PDF: 12 pages
Proc. SPIE 5501, High-Energy Detectors in Astronomy, (29 September 2004); doi: 10.1117/12.550628
Show Author Affiliations
Catherine E. Grant, MIT Ctr. for Space Research (United States)
Mark W. Bautz, MIT Ctr. for Space Research (United States)
Steven E. Kissel, MIT Ctr. for Space Research (United States)
Beverly LaMarr, MIT Ctr. for Space Research (United States)


Published in SPIE Proceedings Vol. 5501:
High-Energy Detectors in Astronomy
Andrew D. Holland, Editor(s)

© SPIE. Terms of Use
Back to Top