Several laboratories in Europe have realised the ITS-90 within the range 13.8 K to 303 K, using capsule-type standard platinum resistance thermometers. These realisations need to be compared.
It is proposed to collect together a group of thermometers from paticipating laboratories and to compare them at the fixed points of the ITS-90 and at a number of intermediate temperatures.
Each participant is invited to supply 1 or 2 thermometers, preferably from different sources of manufacture, which they had previously calibrated in terms of the ITS-90. A total of up to 12 thermometers would be intercompared at NPL and the results would be used to asses the reproducibility and non-uniqueness of the ITS-90 in Europe.