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Proceedings Paper

X-ray diffraction properties of highly oriented pyrolytic graphite
Author(s): Andreas K. Freund; Anneli Munkholm; Sean Brennan
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Paper Abstract

The x-ray diffraction properties of highly oriented pyrolytic graphite (HOPG) were studied for x-ray energies ranging from 4 to 60 keV. In particular, the secondary extinction thickness was determined by recording the peak and integrated reflectivity as a function of depth below the surface. The results showed that for the high quality material investigated a thickness of 200 to 300 micrometers was sufficient to get 80% of the maximum reflectivity that is obtained for a very thick plate. Primary extinction was important for low energy and still persisted at higher energies. Inhomogeneities of the mosaic structure were observed, too, that make this material not a truly ideal mosaic monochromator crystal. However, quite high peak reflectivities between 35% and 58% were measured at FWHM of 0.25 to 0.45 degrees. A 200 micrometers thick plate was then prepared and glued on a bending device to manufacture a monochromator or analyzer with variable curvature that works from flat down to a minimum bending radius of 10 cm. The successful tests of this device confirmed that HOPG plates much thinner than those commonly used as x-ray monochromators and analyzers still have high efficiency and can be curved to achieve dynamical focusing.

Paper Details

Date Published: 22 November 1996
PDF: 12 pages
Proc. SPIE 2856, Optics for High-Brightness Synchrotron Radiation Beamlines II, (22 November 1996); doi: 10.1117/12.259851
Show Author Affiliations
Andreas K. Freund, Stanford Synchrotron Radiation Lab. (United States)
Anneli Munkholm, Stanford Synchrotron Radiation Lab. (United States)
Sean Brennan, Stanford Synchrotron Radiation Lab. (United States)


Published in SPIE Proceedings Vol. 2856:
Optics for High-Brightness Synchrotron Radiation Beamlines II
Lonny E. Berman; John Arthur, Editor(s)

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