Stability test of Pt/Pd thermocouples at aluminum freezing point

Stability tests of 6 Pt/Pd thermocouples at the aluminum freezing point (660.323/spl deg/C) were carried out by 8 laboratories. The purpose of the test was to investigate if Pt/Pd thermocouple is suitable for using as transfer standard in temperature standard traceability system in Japan. As a result, a maximum drift of Pt/Pd thermocouple was less than 50 mK, that is enough to small to use as thermocouple standard.