High-precision Calibration of Long Gauge Blocks Using the Vacuum Wavelength Comparator

Abstract

The calibration of long gauge blocks of up to 1 m using the vacuum wavelength comparator according to Kösters, and three laser wavelength standards recommended by the CIPM, is described. The relative uncertainty of this calibration is shown to be as low as 1,3 × 10-8 for suitable gauge blocks of 1 m length. In addition, a discontinuity of the length calibration of 5 × 10-8 was introduced when the international temperature scales were changed.