ADVANCES AND NEW TECHNIQUES IN LENGTH MEASUREMENTS BY OPTICAL INTERFEROMETRY

Alexandre Titov, Igor Malinovsky
Abstract:
Studies of a long gauge block Kösters interferometer, performed at INMETRO, and the results of the CIPM Key Comparison CCL-2 show that the uncertainty in realization of the SI length unit achieved with this type of instrument in the range of 500 mm is ~1 part in 108. Basic advances in philosophy and techniques of high-precision temperature measurements, realized in Brazil in the last few ears, permit to reduce crucially the uncertainty of length measurements by optical interferometry and to reach the Nanometrolgy regime in artifacts with nominal lengths above 100 mm. New measurement and calibration techniques give an opportunity to realize the temperature measurement of a particular point on the GB surface inside the interferometer with a total uncertainty below 0.1 mK, realizing the measurement without the contributions of the temperature gradient in the GB and velocity error. The demonstrated reproducibility in length measurements of 100-mm steel gauge block is at the level of 58 pm.
Keywords:
accuracy, interferometry, temperature
Download:
PWC-2006-TC14-005u.pdf
DOI:
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Event details
Event name:
XVIII IMEKO World Congress
Title:

Metrology for a Sustainable Development

Place:
Rio de Janeiro, BRAZIL
Time:
17 September 2006 - 22 September 2006