A bilateral comparison of the length of long gauge blocks determined interferometrically is to be made. The comparison would be an arrangement similar to the previous EUROMET comparison of long gauge blocks [Darnedde and Helmcke 1996 Metrologia, 33, 485 - 91].
A pair of gauge blocks, of nominal length 400 mm (provided by SP) and 800 mm (by MIKES), are to be measured at both laboratories using the laser interferometers developed for the measurement of long gauge blocks.
One of the present participants (SP) has recently completed the construction of a laser interferometer for the calibration of long gauge blocks [Frennberg, Johansson, Källberg, Kärn and Pendrill 1998, to be published].
The other laboratory (MIKES) will use its existing laser interferometer [Ikonen, Kauppinen, Korkolainen, Luukkainen and Riski 1991 Appl. Opt., 30, 4477 - 8]