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

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 14 K to 302 K and 7 standard long-stem type platinum thermometers in the range 0 °C to 156 °C. The non-uniqueness is found to be less than 0.3 mK in almost all ranges, except a few subranges that cover from 14 K to 54 K. The inconsistency between subranges is larger than the expected value. Both must be included in uncertainty sources in resistance thermometry.