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Standard Platinum Resistance Thermometer Calibrations from the Ar TP to the Ag FP



Gregory F. Strouse


The National Institute of Standards and Technology (NIST) is in charge of realizing, maintaining, and disseminating the international Scale of 1990 (ITS-90). The Standard Platinum Resistance Thermometer (SPRT) Calibration Laboratory of the NIST Thermometry Group realizes the ITS-90 from the argon triple point (Ar TP, 189.3442 °C) to the silver freezing point (Ag FP, 961.78 °C) for the calibration of SPRTs. This special publication describes the calibration services, methods, measurement assurance, and uncertainties for the NIST ITS-90 calibration SPRTs.
Special Publication (NIST SP) - 250-81
Report Number


Fixed-point cells, International Temperature Scale of 1990, ITS-90, Standard Platinum Resistance Thermometer, SPRT, SPRT Cal.
Created December 19, 2007, Updated November 10, 2018