In the International Temperature Scale of 1990 (ITS-90), temperatures above the freezing temperature of silver are defined with radiation thermometers calibrated using spectral radiance ratios to one of the silver-, gold- or copper-freezing temperature blackbodies and Planck's radiance law. However, due to the use of spectral radiance ratios, the temperature uncertainties of the ITS-90 defined using these thermometers increase as the square of the temperature ratios. Using absolute radiometry, thermodynamic temperatures can be determined with radiation thermometers traceable to a cryogenic radiometer, and the resulting temperature uncertainties can be lower than those measured using the ITS-90 techniques. We describe the development of a new international temperature scale based upon absolute radiometry.
Proceedings Title: NCSL International 2003 Workshop and Symposium Conference Proceedings | | |
Conference Dates: August 17-21, 2003
Conference Title: National Conference of Standards Laboratories International
Pub Type: Conferences
blackbodies, cryogenic radiometer, detector-based radiometry, International Temperature Scale of 1990, radiation thermometer