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AXAF VETA-I mirror encircled energy measurements and data reductionThe 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.
Document ID
19930016999
Acquisition Source
Legacy CDMS
Document Type
Other
Authors
Zhao, Ping (Smithsonian Astrophysical Observatory Cambridge, MA, United States)
Freeman, Mark D. (Smithsonian Astrophysical Observatory Cambridge, MA, United States)
Hughes, John P. (Smithsonian Astrophysical Observatory Cambridge, MA, United States)
Kellogg, Edwin M. (Smithsonian Astrophysical Observatory Cambridge, MA, United States)
Nguyen, Dan T. (Smithsonian Astrophysical Observatory Cambridge, MA, United States)
Joy, Marshall (Smithsonian Astrophysical Observatory Cambridge, MA, United States)
Kolodziejczak, Jeffery J. (Smithsonian Astrophysical Observatory Cambridge, MA, United States)
Date Acquired
September 6, 2013
Publication Date
October 23, 1992
Publication Information
Publication: VETA-I X Ray Test Analysis
Subject Category
Optics
Accession Number
93N26188
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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