Comparison of Fixed Point Realisations between Inmetro and PTB

Abstract

An interlaboratory comparison in the temperature range between −190 °C and 420 °C was organised between the National Institute of Quality, Normalisation and Industrial Quality (Inmetro), Brazil, and the Physikalisch Technische Bundesanstalt (PTB), Germany. This comparison followed the same protocol as the EUROMET project 552 comparison and was carried out in the years 2001–2002. A standard platinum resistance thermometer (SPRT) of 25 Ω was calibrated at the temperature fixed points of Ar, Hg, the triple point of water (TWP), Ga, In, Sn and Zn, with at least three realisations of each fixed point at both institutes. The uncertainty evaluation is given by Inmetro and some differences in the calibration procedures or in the measuring instruments used are described. The agreement between the results of laboratories was not in all cases within the combined uncertainties. Results of other comparisons are presented, which give additional information on the equivalence of the realised temperature scales.