Comparison of the realizations of the ITS-90 over the range from 83.8058 K to 692.677 K

Abstract

In this paper the interlaboratory comparison in the field of measurement of temperature is presented. Within intercomparison calibration of a SPRT at fixed points in the range from the triple point of argon 83.8058 K (−189.3442 °C) to the freezing point of zinc 692.677 K (419.527 °C) was performed. The interlaboratory comparison was organized by the University of Ljubljana, Faculty of Electrical Engineering, Laboratory of Metrology and Quality (MIRS/UL-FE/ LMK). The circulating items were two 25 Ω standard platinum resistance (SPRT) thermometers, one metal sheathed and one quartz sheathed. The interlaboratory comparison included maximum of six fixed points of ITS-90 in the range between −190 °C and 420 °C. However, certain laboratories didn't have all the fixed points in the range. They have performed only measurements in the fixed points that they have. Prior to the start of measurements, in case that the laboratory had the freezing point of zinc, annealing was performed as in accordance with protocol. MIRS/UL-FE/LMK performed measurements at the beginning of the interlaboratory comparison and at the end. Prior to the calibration at fixed points in each laboratory, test measurement at the TPW was done in order to assess stability of the instruments.