Investigation of ITS-90 Inconsistencies in Overlap Region of the Water-indium,Water-tin,and Water-zinc Sub-ranges

One of the significant uncertainties in Standard Platinum Resistance Thermometer (SPRT) calibration by fixed-points method is Type I non-uniqueness (sub-range inconsistencies). Sub-ranges water-tin (W ₉ ) and water-indium (W ₁₀ ) lies in the water-zinc (W ₈ ) sub-range of the International Temperature Scale of 1990. Therefore, three sub-range inconsistencies [W ₈ and W ₉ (SRI _8–9 ), W ₈ and W ₁₀ (SRI _8–10 ), and W ₉ and W ₁₀ (SRI _9–10 )] occur. This paper investigated these inconsistencies using the calibration data of 12 SPRTs from six manufacturers. The result shows that the magnitude of the inconsistency for SRI _8–9 , SRI _8–10 , and SRI _9–10 are about 2.5, 2.2 and 1.8 mK, respectively.     

Fabrication and Determination of an Aluminium Fixed Point Cell as a Secondary Standard in Thermocouple Calibration

A new open-type aluminium (Al) fixed-point cell has been fabricated in Puslit Metrologi-LIPI. The cell was successfully characterized by direct comparison with a commercial Al cell. The cell plateau lasted for four hours with a flatness of 0.014 °C, measured as the difference between the beginning and the end of the plateau using a type S thermocouple. The reproducibility of realizations is 0.04 °C; the immersion profile of the cell was measured for 30 mm depth, from the bottom of the cell, and the variation was found to be 0.02 °C. A good agreement within 0.16 °C was measured at the freezing point. Furthermore, the cell improves the entry in Appendix C, calibration and measurement capability (CMC) by 0.24 °C, allowing the cell to be included as a secondary standard of the international temperature scale of 1990 realization in Puslit Metrologi-LIPI.