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Proceedings Paper

AXAF VETA-I mirror encircled energy measurements and data reduction
Author(s): Ping Zhao; Mark D. Freeman; John P. Hughes; Edwin M. Kellogg; Dan T. Nguyen; Marshall K. Joy; Jeffery J. Kolodziejczak
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Paper Abstract

The AXAF VETA-I mirror encircled energy was measured with a series of apertures and two flow gas proportional counters at five X-ray energies ranging from 0.28 to 2.3 keV. The proportional counter has a thin plastic window with an opaque wire mesh supporting grid. Depending on the counter position, this mesh can cause the X-ray transmission to vary as much as +/- 9 percent, which directly translates into an error in the encircled energy. In order to correct this wire mesh effect, window scan measurements were made, in which the counter was scanned in both horizontal (Y) and vertical (Z) directions with the aperture fixed. Post VETA measurement of the VXDS setup were made to determine the exact geometry and position of the mesh grid. Computer models of the window mesh were developed to simulate the X-ray transmission based on this measurement. The window scan data were fitted to such mesh models and corrections were made. After this study, the mesh effect was well understood and the final results of the encircled energy were obtained with an uncertainty of less than 0.8 percent.

Paper Details

Date Published: 21 January 1993
PDF: 16 pages
Proc. SPIE 1742, Multilayer and Grazing Incidence X-Ray/EUV Optics for Astronomy and Projection Lithography, (21 January 1993); doi: 10.1117/12.140609
Show Author Affiliations
Ping Zhao, Smithsonian Astrophysical Observatory (United States)
Mark D. Freeman, Smithsonian Astrophysical Observatory (United States)
John P. Hughes, Smithsonian Astrophysical Observatory (United States)
Edwin M. Kellogg, Smithsonian Astrophysical Observatory (United States)
Dan T. Nguyen, Smithsonian Astrophysical Observatory (United States)
Marshall K. Joy, NASA Marshall Space Flight Ctr. (United States)
Jeffery J. Kolodziejczak, NASA Marshall Space Flight Ctr. (United States)

Published in SPIE Proceedings Vol. 1742:
Multilayer and Grazing Incidence X-Ray/EUV Optics for Astronomy and Projection Lithography
Richard B. Hoover; Arthur B. C. Walker II, Editor(s)

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