25 August 2005 Cryogenic system for interferometry of high-precision optics at 20 K: design and performance
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This report describes the facility and experimental methods at the Goddard Space Flight Center Optics Branch for the measurement of the surface figure of cryogenically-cooled spherical mirrors using standard phase-shifting interferometry, with a standard uncertainty below 2nm rms. Two developmental silicon carbide mirrors were tested: both were spheres with radius of curvature of 600 mm, and clear apertures of 150 mm. The mirrors were cooled within a cryostat, and the surface figure error measured through a fused-silica window. The GSFC team developed methods to measure the change in surface figure with temperature (the cryo-change) with a combined standard uncertainty below 1 nm rms. This paper will present the measurement facility, methods, and uncertainty analysis.
© (2005) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Peter Blake, Peter Blake, Ronald G. Mink, Ronald G. Mink, John Chambers, John Chambers, F. David Robinson, F. David Robinson, David Content, David Content, Pamela Davila, Pamela Davila, } "Cryogenic system for interferometry of high-precision optics at 20 K: design and performance", Proc. SPIE 5904, Cryogenic Optical Systems and Instruments XI, 59040S (25 August 2005); doi: 10.1117/12.614160; https://doi.org/10.1117/12.614160

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