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Proceedings Paper

Theoretical evaluation of the effects of molecular contaminants on grazing incidence mirrors
Author(s): Jack T. Sanders
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Paper Abstract

Molecular contaminants degrade the optical or thermal properties of spacecraft systems. In the case of grazing incidence mirrors, they may even increase the system throughput at certain wavelengths. Theoretical calculations using a semi-imprircal model developed by Henke, Davis and Gullickson at the Lawrence Berkeley National Laboratory show the effect of varying film thickness' on mirror reflectivity.2 The reflectivity is a product of the base material and any thin films, including molecular contaminants. The effect on nickel, gold, and Zerodur substrates are evaluated with polycarbonate, polypropylene and poly(dimenthyl silicone) contaminants in the range of 5 to 100 Angstroms x-ray wavelength. X-rays pass through the film until they meet an atom; they are then scattered elastically or absorbed. Photoabsorption occurs when the photon energy is equal to or greater than the energy required to promote an inner shell electron out of the atom. Strategies for evaluating contaminant effects with different light sources are included, taking into account the scattering cross section, expressed as mirror reflectance, of the materials involved.

Paper Details

Date Published: 20 September 2000
PDF: 11 pages
Proc. SPIE 4096, Optical Systems Contamination and Degradation II: Effects, Measurements, and Control, (20 September 2000); doi: 10.1117/12.400831
Show Author Affiliations
Jack T. Sanders, Swales Aerospace (United States)

Published in SPIE Proceedings Vol. 4096:
Optical Systems Contamination and Degradation II: Effects, Measurements, and Control
Philip T. C. Chen; O. Manuel Uy, Editor(s)

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