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Proceedings Paper

Diffraction geometry optimization with polycapillary x-ray optics
Author(s): Walter M. Gibson; Carolyn A. MacDonald; Johannes B. Ullrich
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Paper Abstract

Polycapillary optics, shaped arrays consisting of hundreds of thousands of hollow glass capillary tubes, can be used to redirect, collimate, or focus x-ray and low energy neutron beams. X rays emitted over a large angular range from conventional, laboratory-based sources can be transformed into a beam with a small angular divergence or focused onto a small sample or sample area. Focused spot sizes as small as 20 micrometer have been achieved, with flux densities more than two orders of magnitude larger than that produced by pinhole collimation. This results in a comparable decrease in data collection times due to the increase in direct beam intensity and reciprocal space coverage. In addition, the optics can be employed to reduce background and provide more convenient alignment geometries. The inverse dependence of the critical angle for total external reflection on photon energy results in suppression of high energy photons. This effect can be employed to allow the use of higher tube potentials to increase characteristic line emission. Using parallel beam geometries peak shapes are found to be symmetric and independent of angle and sample alignment. Measurements of x- ray diffraction data and crystallographic analysis have been assessed for powders, thin films, minerals, elemental crystals, polymers, and protein crystals.The benefits and limitations of polycapillary optics for such measurements will be reviewed.

Paper Details

Date Published: 23 November 1999
PDF: 10 pages
Proc. SPIE 3767, EUV, X-Ray, and Neutron Optics and Sources, (23 November 1999); doi: 10.1117/12.371117
Show Author Affiliations
Walter M. Gibson, SUNY/Albany (United States)
Carolyn A. MacDonald, SUNY/Albany (United States)
Johannes B. Ullrich, X-Ray Optical Systems, Inc. (United States)

Published in SPIE Proceedings Vol. 3767:
EUV, X-Ray, and Neutron Optics and Sources
Carolyn A. MacDonald; Kenneth A. Goldberg; Juan R. Maldonado; Huaiyu Heather Chen-Mayer; Stephen P. Vernon, Editor(s)

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