The 1990 NIST scales of thermal radiometry

Abstract

Following an absolute NIST measurement of the freezing temperature of gold and the adoption of the International Temperature Scale of 1990 (ITS-90), NIST has adopted new measurement scales for the calibration services based on thermal radiometry. In this paper, the new scales are defined and compared to the ITS-90, and the effects of the scale changes on NIST measurement services in optical pyrometry, radiometry, and photometry are assessed quantitatively. The changes in reported calibration values are within quoted uncertainties, and have resulted in small improvements in accuracy and better consistency with other radiometric scales.

A systematic neutron reflectometry study on hydrogen absorption in thin Mg1-xAlx alloy films Special issue on Neutron Scattering in Canada.

“…With detector-based radiometric standards achieving very small uncertainties in the 0.01% range or below (see section IV), several NMIs now measure thermodynamic temperature by radiometric means, traceable to those detector-based standards, rather than using an ITS-90 derived source-based scale [38][39][40][41][42][43][44][45][46]. This practice also anticipates changes in thermometry, where the new mise-en-pratique for the definition of the kelvin (currently being prepared by the Consultative Committee for Thermometry (CCT))…”

Spectral irradiance calibrations at the National Research Council of Canada (NRC)

“…There have been two dominant methods for performing the realization of these primary sources, which can be called the sourcebased and the detector-based methods. The two sources that are typically used in the source-based method are (1) blackbody radiators, whose output is calculated from the Planck equation when the temperature of the blackbody is known [7], and (2) synchrotron radiators, whose output can be determined from the calculable radiance of accelerating charged particles [8]. The detector-based method depends on the measurement of absolute quantities of radiant flux by absolute radiometers [9], which compare the heating caused by the absorption of the radiant flux with the heating caused by a known amount of electrical power.…”

Photometry, radiometry and ‘the candela’: evolution in the classical and quantum world

“…With detector-based radiometric standards achieving very small uncertainties in the 0.01% range or below (see section IV), several NMIs now measure thermodynamic temperature by radiometric means, traceable to those detector-based standards, rather than using an ITS-90 derived source-based scale [38][39][40][41][42][43][44][45][46].…”