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Characterization of Multilayers as X-Ray Dispersion Devices

Published online by Cambridge University Press:  25 February 2011

John V. Gilfrich
Affiliation:
Condensed Matter Physics Branch, Naval Research Laboratory, Washington, DC 20375–5000
Dennis B. Brown
Affiliation:
Condensed Matter Physics Branch, Naval Research Laboratory, Washington, DC 20375–5000
David L. Rosen
Affiliation:
Condensed Matter Physics Branch, Naval Research Laboratory, Washington, DC 20375–5000
Ralph K. Freitag
Affiliation:
Condensed Matter Physics Branch, Naval Research Laboratory, Washington, DC 20375–5000
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Abstract

The appropriate application of multilayers as x-ray dispersion devices requires that their diffraction characteristics be understood. Conventional models, based on perfect-crystal and mosaic-crystal theories, predict diffraction efficiencies (integral reflection coefficients) significantly larger than values measured experimentally. It has been shown that introduction of surface roughness effects into the model can promote agreement between experimental and theoretical values, while the presence of other types of defects produce changes too small in magnitude to explain the discrepancy. Because it is reasonably well agreed that the resolving power of multilayers is only moderate, compared to the more conventional “crystal” dispersing devices, it is important to be able to predict or measure that parameter in order to assess the usefulness for a particular application. Experimental measurements and theoretical calculations have been carried out on multilayers (almost exclusively tungsten/carbon) prepared to have 2d-spacings from 50 to 140A. The experimental work used both singlecrystal and double-crystal spectrometers; the calculations used the crystal diffraction model, as modified to include surface roughness.

Type
Research Article
Copyright
Copyright © Materials Research Society 1988

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Footnotes

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Also at Sachs/Freeman Associates, 1401 McCormick Drive, Landover, MD 20785.

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New Mexico State University, Las Cruces, NM 88001.

References

REFERENCES

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