AXAF VETA-I Mirror Encircled Energy Measurements and Data Reduction

Ping Zhao, Mark D. Freeman, John P. Hughes, Edwin M. Kellogg, Dan T. Nguyen, Marshall Joy, Jeffery J. Kolodziejczak

Research output: Contribution to journalConference articlepeer-review

1 Scopus citations


The AXAF VETA-I mirror encircled energy wa.s 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 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%.

Original languageEnglish (US)
Pages (from-to)75-90
Number of pages16
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - Jan 21 1993
Externally publishedYes
EventMultilayer and Grazing Incidence X-Ray/EUV Optics for Astronomy and Projection Lithography 1992 - San Diego, United States
Duration: Jul 22 1992 → …

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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