Cryogenic distortion at 4.4 K of a 50-cm-diameter spherical beryllium mirror fabricated to reduce cryogenic distortion and hysteresis

Gordon C. Augason; Dana S. Clarke; David D. Norris; Roger A. Paquin; John M. Kincade

doi:10.1117/12.225299

23 October 1995 Cryogenic distortion at 4.4 K of a 50-cm-diameter spherical beryllium mirror fabricated to reduce cryogenic distortion and hysteresis

Gordon C. Augason, Dana S. Clarke, David D. Norris, Roger A. Paquin, John M. Kincade

Author Affiliations +

Proceedings Volume 2543, Silicon Carbide Materials for Optics and Precision Structures; (1995) https://doi.org/10.1117/12.225299
Event: SPIE's 1995 International Symposium on Optical Science, Engineering, and Instrumentation, 1995, San Diego, CA, United States

Abstract

A 50 cm diameter, beryllium mirror was fabricated and cryogenically tested as a joint project between NASA-Ames Research Center and Jet Propulsion Laboratory. The purpose of this project was to determine the cryogenic distortion and hysteresis of a large, state-of-the-art beryllium mirror when cooled to liquid helium temperatures. The mirror blank was HIPed from I-70 special beryllium and machined to a plano-concave sphere with a 200 cm radius of curvature. The blank was annealed, acid etched, and thermally cycled may times during machining, figuring, and polishing to reduce stress. The mirror was tested twice to liquid helium temperature using the Ames Research Center Cryogenic Test Facility. No hysteresis or temporal instability was measured in the two tests. The cryogenic distortion was 0.5 p-v. This distortion is comparable to fused silica and is the lowest for any beryllium mirror tested by this facility.

Citation Download Citation

Gordon C. Augason, Dana S. Clarke, David D. Norris, Roger A. Paquin, and John M. Kincade "Cryogenic distortion at 4.4 K of a 50-cm-diameter spherical beryllium mirror fabricated to reduce cryogenic distortion and hysteresis", Proc. SPIE 2543, Silicon Carbide Materials for Optics and Precision Structures, (23 October 1995); https://doi.org/10.1117/12.225299

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available