NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Minimizing Uncertainty in Cryogenic Surface Figure MeasurementA new facility at the Goddard Space Flight Center is designed to measure with unusual accuracy the surface figure of mirrors at cryogenic temperatures down to 12 K. The facility is currently configured for spherical mirrors with a radius of curvature (ROC) of 600 mm, and apertures of about 150 mm or less. The goals of the current experiment were to 1) Obtain the best possible estimate of test mirror surface figure, S(x,y) at 87 K and 20 K; 2) Obtain the best estimate of the cryo-change, Delta (x,y): the change in surface figure between room temperature and the two cryo-temperatures; and 3) Determine the uncertainty of these measurements, using the definitions and guidelines of the ISO Guide to the Expression of Uncertainty in Measurement. A silicon mirror was tested, and the cry-change from room temperature to 20K was found to be 3.7 nm rms, with a standard uncertainty of 0.23 nm in the rms statistic. Both the cryo-change figure and the uncertainty are among the lowest such figures yet published. This report describes the facilities, experimental methods, and uncertainty analysis of the measurements.
Document ID
20050180347
Acquisition Source
Goddard Space Flight Center
Document Type
Preprint (Draft being sent to journal)
Authors
Blake, Peter
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Mink, Ronald G.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Chambers, John
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Robinson, F. David
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Content, David
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Davila, Pamela
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
August 23, 2013
Publication Date
January 1, 2005
Subject Category
Engineering (General)
Meeting Information
Meeting: Precision Interferometric Metrology
Location: Middletown, CT
Country: United States
Start Date: July 20, 2005
End Date: July 22, 2005
Sponsors: American Society for Precision Engineering
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available