Determination Model of Phase-Change Correction for High Precision Gauge Block Calibration Pawat Phuaknoi * Samana Phiengbangyang , Jariya Buajarern , and Anusorn Tonmueanwai Dimensional Metrology Department, National Institute of Metrology (Thailand), Pathumthani

When gauge blocks are calibrated by the laser interferometer technique, phase-change corrections play a crucial role in the measurement uncertainties. In order to reduce the source of uncertainty, phase-change correction must be known and be compensated to the measured results. We present here a determination based on knowledge gained from the stacking method and the known value of phase correction of quartz. It is a fast and robust method. Phase-change correction of any pair of auxiliary plates and gauge blocks can be calculated by using our model. This method is suitable for the national metrological institutes (NMIs), calibration laboratories and industries where calibration of various gauge block materials are carried out and measurement uncertainty within 30 nm is adequate. The experimentally observed phase-change corrections were compared with the calculated values according to our model. The comparison illustrates a good agreement. The measurement uncertainty of gauge block calibration using our interferometer system is 24 nm.

คำสำคัญ : Gauge block, Interferometer, Uncertainty