An international length comparison using vacuum comparators and a photoelectric incremental encoder as transfer standard

Abstract The German national metrology institute, a Japanese company, and a German company have conducted an international length comparison. A photoelectric incremental encoder with a measurement length of 280 mm served as transfer standard. The traceability of measurement results to the SI unit of the metre was uniformly realized through iodine-stabilized lasers and, for the first time all length comparators involved used vacuum interferometry. This made it possible to reach an agreement of calibration results of 5.5 nm over the total length of 280 mm, which corresponds to a relative agreement of 2 × 10−8. The short-range deviations between the calibration results can be characterized with a standard deviation of σ = 0.4 nm. The results attained are consistent with the calculated measurement uncertainty values and are a distinct improvement over previously conducted length comparisons.

[1]  Andrew Yacoot,et al.  Measurement of picometre non-linearity in an optical grating encoder using x-ray interferometry. , 2003 .

[2]  L J Wang,et al.  Precision measurement of the refractive index of air with frequency combs. , 2005, Optics letters.

[3]  Phj Piet Schellekens,et al.  Measurements of the Refractive Index of Air Using Interference Refractometers , 1983 .

[4]  Masaji Sawabe,et al.  A new vacuum interferometric comparator for calibrating the fine linear encoders and scales , 2004 .

[5]  G. B. nsch,et al.  Measurement of the refractive index of air and comparison with modified Edl?n's formulae , 1998 .

[6]  F Bayer-Helms,et al.  Längenstabilität bei Raumtemperatur von Proben der Glaskeramik "Zerodur" , 1985 .

[7]  Harald Bosse,et al.  SUPPLEMENTARY COMPARISON: Final report on CCL-S3 supplementary line scale comparison Nano3 , 2003 .

[8]  Jens Fluegge,et al.  Status of the nanometer comparator at PTB , 2001, Lasers in Metrology and Art Conservation.

[9]  I. Tiemann,et al.  An international length comparison at an industrial level using a photoelectric incremental encoder as transfer standard , 2003 .

[10]  T. J. Quinn,et al.  International Report Practical realization of the definition of the metre (1997) , 1999 .

[11]  T J Quinn,et al.  Practical realization of the definition of the metre, including recommended radiations of other optical frequency standards (2001) , 2003 .

[12]  Estler Wt,et al.  High-accuracy displacement interferometry in air. , 1985 .