Non-Uniqueness of the International Temperature Scale of 1990 in the Range 14K to 433K

Abstract

The non-uniqueness of the International Temperature Scale of 1990 is estimated using 6 standard capsule type platinum resistance thermometers in the range from 14K to 302K and 7 standard long-stem type platinum thermometers in the range 0°C to 156°C. The non-uniqueness among the interpolation thermometers is found to be less than 0.3mK in almost all ranges, except a few subranges that cover from 14K to 54K. The inconsistency between subranges is of the order of 0.3mK in most of the low temperature ranges. The non-uniqueness and the inconsistency are not negligibly small and they should be included in uncertainty sources of temperature measurements.