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Proceedings Paper

New low-density, high-porosity lithium hydride-beryllium hydride foam: properties and applications to x-ray astronomy
Author(s): Jon L. Maienschein; Patrick E. Barry; Frederick E. McMurphy; John S. Bowers
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Paper Abstract

We have developed a low density (30-670 kg/rn3), high porosity (up to 96%) foam containing lithium hydride and amorphous beryllium hydride. This foam may be attractive as the X-ray scauering element in experiments such as the Thomson Scattering Polarimeter as proposed for inclusion in the High Throughput X-Ray Spectroscopy Space Mission, XMM, sponsored by the European Scientific Agency. We discuss ways to synthesize the foam, and report on physical properties such as bulk density and porosity, electron density, uniformity of foam density, concentration of impurities, pore size distribution, and sensitivity to moisture. The composition of the foam can be varied, but equimolar mixtures of LiH and BeH2 give the most vigorous foaming reaction. The force needed to expand the plastic reaction mass into a foam is provided by hydrogen and organic contaminants in the beryllium hydride that are released during the foaming reaction. Simultaneous differential thermal analysis and thermogravimetric analysis show that the reaction is endothermic with very little mass loss. The presence of LiBeH3 as either a reaction intermediate or final product is suggested by the fact that the most vigorous foaming occurs with equimolar mixtures oflithium hydride and beryllium hydride.

Paper Details

Date Published: 1 February 1991
PDF: 8 pages
Proc. SPIE 1343, X-Ray/EUV Optics for Astronomy, Microscopy, Polarimetry, and Projection Lithography, (1 February 1991);
Show Author Affiliations
Jon L. Maienschein, Lawrence Livermore National Lab. (United States)
Patrick E. Barry, Lawrence Livermore National Lab. (United States)
Frederick E. McMurphy, Lawrence Livermore National Lab. (United States)
John S. Bowers, Lawrence Livermore National Lab. (United States)

Published in SPIE Proceedings Vol. 1343:
X-Ray/EUV Optics for Astronomy, Microscopy, Polarimetry, and Projection Lithography

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