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Proceedings Paper

New fabrication processes for dimensionally stable beryllium mirrors
Author(s): Roger A. Paquin; Daniel R. Coulter; David D. Norris; Gordon C. Augason; Mark T. Stier; Marc Cayrel; Thomas B. Parsonage
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Paper Abstract

Stability of beryllium mirrors is said to be unpredictable. Three recent mirrors demonstrate excellent stability. JPL produced a plano-concave, 0.5 m solid test mirror that was machined from a HIP'ed billet of special I-70 Be powder, polished bare and tested to 4K. It was thermally stable and had no hysteresis. The JPL ITTT 0.85 m primary mirror used similar material and processes, but with more stress relied treatments. Tests of this bare-polished, very lightweight single arch hyperboloidal mirror to 5K showed similar excellent results. The ESO VLT chopping secondary is a 1.12 m, machined lightweight, nickel plated, convex paraboloid. Similar fabrication processes are being used but with higher strength I-220 Be. In-processes testing indicates a stable mirror. The results show beryllium to be a stable and predictable mirror material.

Paper Details

Date Published: 19 August 1996
PDF: 11 pages
Proc. SPIE 2775, Specification, Production, and Testing of Optical Components and Systems, (19 August 1996);
Show Author Affiliations
Roger A. Paquin, Advanced Materials Consultant (United States)
Daniel R. Coulter, Jet Propulsion Lab. (United States)
David D. Norris, Jet Propulsion Lab. (United States)
Gordon C. Augason, NASA Ames Research Ctr. (United States)
Mark T. Stier, Hughes Danbury Optical Systems, Inc. (United States)
Marc Cayrel, REOSC (France)
Thomas B. Parsonage, Brush Wellman, Inc. (United States)

Published in SPIE Proceedings Vol. 2775:
Specification, Production, and Testing of Optical Components and Systems
Anthony E. Gee; Jean-Francois Houee, Editor(s)

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