APMP.T-K3.4: key comparison of realizations of the ITS-90 over the range -38.8344 °C to 419.527 °C

Abstract

The APMP bilateral key comparison APMP.T-K3.4 was initiated on the request from RCM-LIPI (Indonesia) to link their national standards to the average reference values (ARVs) of the CCT-K3. Korea Research Institute of Standards and Science (KRISS, Republic of Korea) provided the linkage to the CCT-K3 for temperatures ranging from -38.8344 °C to 419.527 °C. In the APMP.T-K3.4, two standard platinum resistance thermometers (SPRTs) were chosen as the transfer instruments and were calibrated at the ITS-90 fixed-points in the comparison range. The fixed-points in this comparison included Zn freezing point (419.527 °C), Sn freezing point (231.928 °C), In freezing point (156.5985 °C), Ga melting point (29.7646 °C), and Hg triple point (-38.8344 °C). The comparison was carried out in a participant-pilot-participant sequence where KRISS served as the pilot. The linkage was based on the fixed-point resistance ratios of RCM-LIPI relative to the ARVs of the CCT-K3 via the difference between the fixed-point resistance ratios of KRISS and the ARVs of the CCT-K3. The temperature differences between the national standards of RCM-LIPI and the ARVs of the CCT-K3 were within the evaluated comparison uncertainties of the ATPM.T-K3.4. This report provides detailed information on the comparison results, linkage mechanism, and the Degree of Equivalence of the RCM-LIPI relative to the institutes having participated in the CCT-K3. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

A new interpolation equation in the ITS-90 subrange from the triple point of water to the freezing point of indium

“…Using a data set of 30 SPRTs calibrations from various countries and laboratories [22][23][24][25][26][27][28][29], the SRIs between the new equation and the reference piecewise function are calculated and analysed. The peak value of SRIs shows a significant decrease to 0.21 mK compared to that of ITS-90 in the same subrange which is 0.91 mK and shows a reduction of 77%.…”

“…In this section, SRI, NU3 and PoU of the proposed interpolation equation are discussed respectively. Data collection and preparation for SRI are composed of two parts: the historical data from a series of CCT reports [22][23][24][25][26][27][28][29] and the experimental data run for this study. NU3 analysis is based on the experimental data run for this study solely.…”