Measurement of the effects of particulate contamination on X-ray reflectivityBecause particles of sizes larger than a few tenths microns adversely affect high resolution X-ray telescopes by scattering and absorbing X-rays, the cleanliness required to maintain the about 1 percent overall calibration precision desired for the Advanced X-ray Astrophysics Facility (AXAF) is being investigated. At the grazing angles used for the AXAF mirrors, each particle shadows a surface area about 100 times its geometric area, necessitating glass occlusion specifications much more stringent than typically stipulated for visible-light particulate contamination. On test flats coated with gold, controlled levels of contamination have been deposited spanning the range from 5 x 10 to the -5th to 0.005 fractional area covered, and the absorption component of extinction has been measured over a range of grazing angles and X-ray energies to verify the predicted effects of particulate contamination.
Document ID
19900051974
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Slane, P. (Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Mclaughlin, E. R. (Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Schwartz, D. A. (Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Van Speybroeck, L. P. (Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Bilbro, J. W. (NASA Marshall Space Flight Center Huntsville, AL, United States)