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Proceedings Paper

High-Energy Transmission Grating Spectrometer for the Advanced X-ray Astrophysics Facility (AXAF)
Author(s): Thomas H. Markert; Claude R. Canizares; Daniel Dewey; Michael McGuirk; Chris S. Pak; Mark L. Schattenburg
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Paper Abstract

The High Energy Transmission Grating Spectrometer (HETGS) is one of the scientific instruments being developed for NASA's Advanced X-ray Astrophysics Facility (AXAF), scheduled for launch in 1998. The HETGS will be capable of measuring spectra with high resolution and sensitivity from a variety of compact and slightly extended cosmic X-ray sources. In this paper we describe the overall design of the HETGS and its expected scientific performance. The HETGS consists of two arrays of gold grating elements (High-Energy gratings [HEGs] and Medium-Energy Gratings [MEGs] which are optimized for the energy ranges 0.8-10 keV [HEG] and 0.4-5 keV [MEG]). The details of the grating elements and their fabrication methods are described in Schattenburg et al. (this conference). The gratings are mounted on a support plate which can be inserted immediately behind the AXAF telescope assembly. X-rays diffracted by the gratings are dispersed onto the focal plane detector strips which are components of either of the two AXAF imagers (the HRC or ACIS). The two kinds of gratings are oriented at a slight angle with respect to each other so that the dispersed spectra form a shallow 'X' on the readout device. The gratings and detectors are mounted on a Rowland torus to correct for most of the optical aberrations. The grating-detector combination achieves resolving powers (E/(Delta) E) as high as 1000 at some energies, and has significant effective area (10-200 square cm) for all energies 400 eV < E < 10 keV.

Paper Details

Date Published: 16 September 1994
PDF: 13 pages
Proc. SPIE 2280, EUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy V, (16 September 1994); doi: 10.1117/12.186812
Show Author Affiliations
Thomas H. Markert, Massachusetts Institute of Technology (United States)
Claude R. Canizares, Massachusetts Institute of Technology (United States)
Daniel Dewey, Massachusetts Institute of Technology (United States)
Michael McGuirk, Massachusetts Institute of Technology (United States)
Chris S. Pak, Massachusetts Institute of Technology (United States)
Mark L. Schattenburg, Massachusetts Institute of Technology (United States)


Published in SPIE Proceedings Vol. 2280:
EUV, X-Ray, and Gamma-Ray Instrumentation for Astronomy V
Oswald H. W. Siegmund; John V. Vallerga, Editor(s)

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