ACIS UV/optical blocking filter calibration at the Natl. Synchrotron Light Source

George Chartas, Gordon P. Garmire, John A. Nousek, Leisa K. Townsley, Forbes R. Powell, Richard L. Blake, Dale E. Graessle

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Scopus citations


Measurements of the transmission properties of the AXAF CCD imaging spectrometer (ACIS) UV/optical blocking filters were performed at the National Synchrotron Light Source at Brookhaven Laboratories. The X-ray transmissions of two Al:Si/LEXAN/Al:Si three layer filters were measured between 260 and 3000 eV. The main purpose of the calibration was to determine a model transmission function with an accuracy of better than 1 percent. We present results from fits of model transmission functions to the measured x-ray transmission data. Detailed fine energy scans above the Al-K and C-K absorption edges revealed the presence of fine oscillations of the x-ray transmission. These features are most likely extended x-ray absorption fine structures (EXAFS). The amplitude of the EXAFS oscillations above the Al absorption edge is about 5 percent of the mean value of the x-ray transmission. EXAFS theory predicts a temperature dependence on the amplitude of the EXAFS oscillations. This dependence arises from the fact that thermal vibrations of the atoms in a solid produce a phase mismatch of the backscattered electron wave function. Since the ACIS filters will be at a much lower temperature on orbit we provide a prediction of the EXAFS component for the expected on orbit temperature of the ACIS filters.

Original languageEnglish (US)
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
EditorsRichard B. Hoover, Arthur B.Jr. Walker
Number of pages11
StatePublished - 1996
EventMultilayer and Grazing Incidence X-Ray/EUV Optics III - Denver, CO, USA
Duration: Aug 5 1996Aug 6 1996

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering


OtherMultilayer and Grazing Incidence X-Ray/EUV Optics III
CityDenver, CO, USA

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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