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Proceedings Paper

AXAF grating efficiency measurements with calibrated nonimaging detectors
Author(s): Daniel Dewey; Jeremy J. Drake; Richard J. Edgar; Kendra Michaud; Peter W. Ratzlaff
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Paper Abstract

In Phase 1 of AXAF testing at the X-Ray Calibration Facility (XRCF), calibrated flow proportional counters (FPCs) and solid-state detectors were used both in the focal plane and as beam-normalization detectors. This use of similar detectors in the beam and focal plane combined with detailed fitting of their pulse-height spectra allowed accurate measurements of the HRMA absolute effective area with minimum influence of source and detector effects. This paper describes the application of these detectors and fitting techniques to the analysis of effective area and efficiency measurements of the AXAF transmission gratings, the High Energy Transmission Grating (HETG) and the Low Energy Transmission Grating. Because of the high dispersion of these gratings the analysis must be refined. Key additional ingredients are the inclusion of detailed x-ray source models of the K and L lines based on companion High-Speed Imager microchannel-plate data and corrections to the data based on high-fidelity ray-trace simulations. The XRCF- measured efficiency values that result from these analyses have systematic errors estimated in the 10-20 percent range. Within these errors the measurements agree with the pre-XRCF laboratory-based efficiency models of the AXAF grating diffraction efficiencies.

Paper Details

Date Published: 19 November 1998
PDF: 16 pages
Proc. SPIE 3444, X-Ray Optics, Instruments, and Missions, (19 November 1998); doi: 10.1117/12.331271
Show Author Affiliations
Daniel Dewey, Massachusetts Institute of Technology (United States)
Jeremy J. Drake, Smithsonian Astrophysical Observatory (United States)
Richard J. Edgar, Smithsonian Astrophysical Observatory (United States)
Kendra Michaud, Smithsonian Astrophysical Observatory (United States)
Peter W. Ratzlaff, Smithsonian Astrophysical Observatory (United States)

Published in SPIE Proceedings Vol. 3444:
X-Ray Optics, Instruments, and Missions
Richard B. Hoover; Arthur B. C. Walker II, Editor(s)

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