Improvements in the accuracy and the repeatability of long trace profiler measurements
- Brookhaven National Laboratory, P. O. Box 5000, Upton, New York 11973 (United States)
- Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, Arizona 85721 (United States)
- Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)
Modifications of the long trace profiler at the Advanced Photon Source at Argonne National Laboratory have significantly improved its accuracy and repeatability for measuring the figure of large flat and long-radius mirrors. Use of a Dove prism in the reference beam path corrects phasing problems between mechanical errors and thermally induced system errors. A single reference correction now completely removes both of these error signals from the measured surface profile. The addition of a precision air conditioner keeps the temperature in the metrology enclosure constant to within {plus_minus}0.1&hthinsp;{degree}C over a 24-h period and has significantly improved the stability and the repeatability of the measurements. Long-radius surface curvatures can now be measured absolutely with a high degree of confidence. These improved capabilities are illustrated with a series of measurements of a 500-mm-long mirror with a 5-km radius of curvature. The standard deviation in the average of ten slope profile scans is 0.3 {mu}rad, and the corresponding standard deviation in the height error is 4.6 nm. {copyright} 1999 Optical Society of America
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- DOE Contract Number:
- AC02-98CH10886; W-31109-ENG-38
- OSTI ID:
- 698825
- Journal Information:
- Applied Optics, Vol. 38, Issue 25; Other Information: PBD: Sep 1999
- Country of Publication:
- United States
- Language:
- English
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