INTERNATIONAL COMPARISON OF RADIATION TEMPERATURE SCALES AMONG 5 NATIONAL METROLOGICAL LABORATORIES USING A TRANSFER STANDARD RADIATION THERMOMETER

Round-robin measurements with a transfer standard radiation thermomete r were organized by the NRLM in the framework of a three-year joint re search agreement with the NIST, the IMGC and the PTB: the NPL also too k part in this exercise. The aim of the study was to assess the mutual traceability of the ITS-90 temperature scales established by the diff erent laboratories in the high-temperature range (above 1000 degrees C ). The thermometer was a monochromatic (0,65 mu m) silicon-detector th ermometer belonging to the NRLM. It was circulated in the period from May to July 1993 and was calibrated by all the participants against th eir local reference thermometers. The temperature interval from 1000 d egrees C to 2000 degrees C was covered by all the participants, but so me extended the range down to 800 degrees C or up to 2700 degrees C. T he results indicate that all the calibrations agree to within 0,5 degr ees C at 1000 degrees C and to within 2 degrees C at 2000 degrees C.