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

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Author(s): Joachim Fischer; M. DePodesta; K. D. Hill; Michael R. Moldover; Laurent Pitre; R. Rusby; Peter Steur; Osamu Tamura; R. White; L. Wolber;
Title: Present Estimates of the Differences Between Thermodynamic Temperatures and the ITS-90
Published: January 29, 2011
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.
Conference: Joint International Symposium on Temperature, Humidity, Moisture and Thermal Measurements in Industry and Science
Proceedings: 2010 TEMPMEKO & ISHM
Volume: 32
Pages: pp. 12 - 25
Location: Portoro?, -1
Dates: May 31-June 4, 2010
Keywords: differences, T ‹ T90, International Temperature Scale ITS-90, primary thermometry, thermodynamic temperature
Research Areas: Measurement Standards, Calibrations (Thermodynamic), International System (SI) of Units, SI (Thermodynamics Units), Standards, Chemical Engineering & Processing, Thermometry, Thermometry, Manufacturing, Chemistry, Metrology
PDF version: PDF Document Click here to retrieve PDF version of paper (337KB)