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Proceedings Paper

Composition of the Chandra ACIS contaminant
Author(s): Herman L. Marshall; Allyn Tennant; Catherine E. Grant; Adam P Hitchcock; Stephen L. O'Dell; Paul P. Plucinsky
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Paper Abstract

The Advanced CCD Imaging Spectrometer (ACIS) on the Chandra X-ray Observatory is suffering a gradual loss of low energy sensitivity due to a buildup of a contaminant. High resolution spectra of bright astrophysical sources using the Chandra Low Energy Transmission Grating Spectrometer (LETGS) have been analyzed in order to determine the nature of the contaminant by measuring the absorption edges. The dominant element in the contaminant is carbon. Edges due to oxygen and fluorine are also detectable. Excluding H, we find that C, O, and F comprise >80%, 7%, and 7% of the contaminant by number, respectively. Nitrogen is less than 3% of the contaminant. We will assess various candidates for the contaminating material and investigate the growth of the layer with time. For example, the detailed structure of the C-K absorption edge provides information about the bonding structure of the compound, eliminating aromatic hydrocarbons as the contaminating material.

Paper Details

Date Published: 3 February 2004
PDF: 12 pages
Proc. SPIE 5165, X-Ray and Gamma-Ray Instrumentation for Astronomy XIII, (3 February 2004); doi: 10.1117/12.508310
Show Author Affiliations
Herman L. Marshall, Massachusetts Institute of Technology (United States)
Allyn Tennant, NASA Marshall Space Flight Ctr. (United States)
Catherine E. Grant, Massachusetts Institute of Technology (United States)
Adam P Hitchcock, McMaster Univ. (Canada)
Stephen L. O'Dell, NASA Marshall Space Flight Ctr. (United States)
Paul P. Plucinsky, Harvard-Smithsonian Ctr. for Astrophysics (United States)

Published in SPIE Proceedings Vol. 5165:
X-Ray and Gamma-Ray Instrumentation for Astronomy XIII
Kathryn A. Flanagan; Oswald H. W. Siegmund, Editor(s)

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