Absolute Primary Radiometric Thermometry

Absolute primary radiometric thermometry is a recently introduced term for an approach to measuring the thermodynamic temperature of a blackbody using the accurate determination of the radiant flux that it emits in a known spectral band and known solid angle. The instrumental and metrological infrastructure for measuring thermodynamic temperature of high-temperature blackbodies are described. Four schemes of the filter radiometer calibration in terms of the spectral power, irradiance, and radiance and corresponding sources of measurement uncertainties are discussed. Calibration facilities on the base of tunable lasers and monochromators are described and compared. The state-of-the-art uncertainties in measuring temperature of the high-temperature blackbodies are discussed.