Present Estimates of the Differences Between Thermodynamic Temperatures and the ITS-90

Published

January 29, 2011

Author(s)

Joachim Fischer, M. DePodesta, K. D. Hill, Michael R. Moldover, Laurent Pitre, R. Rusby, Peter Steur, Osamu Tamura, R. White, L. Wolber

Abstract

In 2005, the Consultative Committee for Thermometry (CCT) recommended the creation of a Mise en pratique for the definition of the kelvin and envisioned that future versions of the Mise en pratique would recommend values of the differences between thermodynamic temperatures and ITS-90 temperatures (T − T90). At the CCT's request, Working Group 4 (WG4) critically reviewed all available measurements of T − T90, the uncertainties, and documented the conversion of older data to the ITS-90. From the review, we provide consensus estimates of T - T90 for selected measurements from 4.2 K to 1358 K as well as a recommendation for T − T90 spanning the range 0.65 K to 4.2 K. WG4 identified certain temperature ranges where researchers are encouraged to undertake additional high-accuracy measurements of T - T90. In order to disseminate the differences T - T90 via the Mise en pratique, we provide two analytic functions for T - T90, one for use below TTPW and one for use above TTPW. The discontinuity of the derivative dT90/dT at TTPW is discussed and the consistency with the results of recent acoustic gas thermometry and with the resistance ratios of platinum resistance thermometers is investigated.

Proceedings Title

2010 TEMPMEKO & ISHM

Volume

32

Conference Dates

May 31-June 4, 2010

Conference Location

Portorož, SI

Conference Title

Joint International Symposium on Temperature, Humidity, Moisture and Thermal Measurements in Industry and Science

Pub Type

Conferences

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Keywords

differences, T – T90, International Temperature Scale ITS-90, primary thermometry, thermodynamic temperature

Citation

Fischer, J. , DePodesta, M. , Hill, K. , Moldover, M. , Pitre, L. , Rusby, R. , Steur, P. , Tamura, O. , White, R. and Wolber, L. (2011), Present Estimates of the Differences Between Thermodynamic Temperatures and the ITS-90, 2010 TEMPMEKO & ISHM, Portorož, SI, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=905075 (Accessed October 11, 2025)