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NIST Methods of Estimating the Impurity Uncertainty Component for ITS-90 Fixed-Point Cells from the Ar TP to the Ag FP

Published

Author(s)

Gregory F. Strouse

Abstract

The NIST Platinum Resistance Thermometry Laboratory uses International Temperature Scale of 1990 (ITS-90) fixed-point cells to calibrate standard platinum resistance thermometers as ITS-90 defining standards. One important component of uncertainty in the realization of ITS-90 fixed-point cells is that of the effect of sample purity on the realized temperature. Four different methods of analysis (mole fraction sum of impurity components, freezing curve, direct comparison, and 1/F realization curve) are used to both estimate and crosscheck the value used for the impurity uncertainty component. The crosschecks provided by the multiple methods are an integral part of our quality assurance. The paper applies each method and the subsequent crosscheck analysis of four different samples of In.
Proceedings Title
Consultative Committee for Thermometry (CCT) | 22nd | Consultative Committee for Thermometry (CCT): Report of the 22nd Meeting to the International Committee for Weights and Measures | BIPM
Conference Dates
May 14-16, 2003
Conference Title
International Bureau of Weights and Measures (Bureau International des Poids et Mesures)

Keywords

Fixed-point cell, fixed-point cell uncertainty, fixed-point impurity, impurity uncertainty, ITS-90, sample impurity, SPRT calibration

Citation

Strouse, G. (2003), NIST Methods of Estimating the Impurity Uncertainty Component for ITS-90 Fixed-Point Cells from the Ar TP to the Ag FP, Consultative Committee for Thermometry (CCT) | 22nd | Consultative Committee for Thermometry (CCT): Report of the 22nd Meeting to the International Committee for Weights and Measures | BIPM (Accessed February 27, 2024)
Created April 1, 2003, Updated February 17, 2017