Several national standards laboratories use a new or a recently improved interferometer system for gauge block measurement.
Since there are no absolute mechanical standards by which the results can be compared, an internatinal intercomparison has to be made.
The audit package will consist of seven steel gauge blocks with nominal length of 1, 3, 5.5, 8, 9, 40, 100 mm. The central length and variation in length of the gauge blocks habe to be measured in their vertical position wrung to a flat baseplate. Phase corrections must be applied. The thermal expansivity will be quoted.
The list of participants with time schedule, handling and measuring instructions will be attached to the pack and be sent by separate mailing to the participants.