Bilateral comparison of freezing point of aluminium

Project Description

A long sterm SPRT is selected and calibrated at MIRS/UL-FE (SI) in AI-FP and W-TP. A second set of measurement will be made at VSL (NL). After its return the SPRT will be recalibrated at MIRS/UL-FE (SI). In the comparison the W will be used.
A final report of the comparison project will be prepared.

Final Report 2012-04-12

The objective of Project EURAMET 1114 (Bilateral comparison of a freezing point of aluminum) in the field of thermometry was to compare realization of a freezing point of aluminum (660.323 °C) between the Dutch national laboratory VSL and the Slovenian national laboratory MIRS/UL-FE/LMK using a long-stem 25 Ω standard platinum resistance thermometer (SPRT). Both laboratories had participated in a number of inter-comparisons on the level of EURAMET and also on BIPM CCT level (VSL). MIRS/UL-FE/LMK laboratory recently acquired a new fixed-point cell which had to be validated in the process of intercomparison. A quartz-sheathed SPRT was selected and calibrated at MIRS/UL-FE/LMK at the aluminum freezing point and at the water triple point. A second set of measurements was made on the same SPRT and at the same fixed points at VSL (NL). After its return, the SPRT was again recalibrated at MIRS/UL-FE/LMK. In the comparison the W value of the SPRT was used. The results of the internal and external intercomparisons confirmed that the new aluminum cell of the MIRS/UL/FE-LMK realizes a temperature that agrees with the VSL aluminum fixed point within the uncertainty limits of both laboratories. The difference between measurements made at VSL and MIRS/UL-FE/LMK was −1.7mK, with an uncertainty of 4.2mK. Furthermore, the results of this bilateral-comparison were compared with results that both laboratories achieved in the EURAMET K4 (Project 820) and were found to be in agreement.
Results were publishd in International Journal of Thermophysics Volume 32, Numbers 7-8, 1518-1524, DOI: 10.1007/s10765-011-1015-x