Paper
3 February 2004 Composition of the Chandra ACIS contaminant
Author Affiliations +
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.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Herman L. Marshall, Allyn Tennant, Catherine E. Grant, Adam P Hitchcock, Stephen L. O'Dell, and Paul P. Plucinsky "Composition of the Chandra ACIS contaminant", Proc. SPIE 5165, X-Ray and Gamma-Ray Instrumentation for Astronomy XIII, (3 February 2004); https://doi.org/10.1117/12.508310
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Cited by 57 scholarly publications.
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KEYWORDS
Data modeling

Absorption

Fluorine

X-rays

Contamination

Opacity

Calibration

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