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Proceedings Paper

Helium cryo testing of an SLMS (silicon lightweight mirrors) athermal optical assembly
Author(s): Marc T. Jacoby; William A. Goodman; H. Philip Stahl; Andrew S. Keys; Jack C. Reily; Ron Eng; James B. Hadaway; William D. Hogue; Jeffrey R. Kegley; Richard D. Siler; Harlan J. Haight; John Tucker; Ernest R. Wright; James R. Carpenter; Jeff E. McCracken
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Paper Abstract

SLMS athermal technology has been demonstrated in the small 4-foot helium cryogenic test chamber located at the NASA/MSFC X-Ray Calibration Facility (XRCF). A SLMS Ultraviolet Demonstrator Mirror (UVDM) produced by Schafer under a NASA/MSFC Phase I SBIR was helium cryo tested both free standing and bonded to a Schafer designed prototype carbon fiber reinforced silicon carbide (Cesic) mount. Surface figure data was obtained with a test measurement system that featured an Instantaneous Phase Interferometer (IPI) by ADE Phase Shift. The test measurement system's minimum resolvable differential figure deformation and possible contributions from test chamber ambient to cryo window deformation are under investigation. The free standing results showed differential figure deformation of 10.4 nm rms from 295K to 27K and 3.9 nm rms after one cryo cycle. The surface figure of the UVDM degraded by lambda/70 rms HeNe once it was bonded to the prototype Cesic mount. The change was due to a small astigmatic aberration in the prototype Cesic mount due to lack of finish machining and not the bonding technique. This effect was seen in SLMS optical assembly results, which showed differential figure deformation of 46.5 nm rms from 294K to 27K, 42.9 nm rms from 294K to 77K, 28.0 nm rms from 294K to 193K and 6.2 nm rms after one cryo cycle.

Paper Details

Date Published: 22 December 2003
PDF: 12 pages
Proc. SPIE 5180, Optical Manufacturing and Testing V, (22 December 2003); doi: 10.1117/12.508378
Show Author Affiliations
Marc T. Jacoby, Schafer Corp. (United States)
William A. Goodman, Schafer Corp. (United States)
H. Philip Stahl, NASA Marshall Space Flight Ctr. (United States)
Andrew S. Keys, NASA Marshall Space Flight Ctr. (United States)
Jack C. Reily, NASA Marshall Space Flight Ctr. (United States)
Ron Eng, NASA Marshall Space Flight Ctr. (United States)
James B. Hadaway, Univ. of Alabama/Huntsville (United States)
William D. Hogue, NASA Marshall Space Flight Ctr. (United States)
Jeffrey R. Kegley, NASA Marshall Space Flight Ctr. (United States)
Richard D. Siler, NASA Marshall Space Flight Ctr. (United States)
Harlan J. Haight, NASA Marshall Space Flight Ctr. (United States)
John Tucker, NASA Marshall Space Flight Ctr. (United States)
Ernest R. Wright, NASA Marshall Space Flight Ctr. (United States)
James R. Carpenter, NASA Marshall Space Flight Ctr. (United States)
Jeff E. McCracken, NASA Marshall Space Flight Ctr. (United States)


Published in SPIE Proceedings Vol. 5180:
Optical Manufacturing and Testing V
H. Philip Stahl, Editor(s)

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