We describe a method of directly determining blackbody radiance temperatures using filter detectors calibrated for absolute spectral power responsivity. The calibrations for absolute power are derived from a highly-accurate cryogenic radiometer, and radiance temperatures are determined using a measurement equation which describes the relationship between the measured signal and the blackbody radiance temperature. Using the calibrated filter detectors, we have measured the radiance temperature of the variable-temperature blackbody used in the dissemination of the U.S. National Scale of Radiance Temperature. We compare the results of theabsolute detector-based method with the temperatures obtained with the NIST Photoelectric Pyrometer (PEP) which determines the radiance temperatures using the methods of ITS-90. We show that the detector-based radiance temperature determinations are in agreement with the measurements of the PEP to within 0.5 K in the range of blackbody temperatures from 2200K to 2800K, and the resultant uncertainties in radiance temperatures using the detector-based method can be factor of two smaller than those found usingthe PEP.
Proceedings Title: Temperature and Thermal Measurements in Industry and Science; TEMPMEKO '99, International Symposium | 7th | | Nmi Van Swinden Laboratorium
Conference Dates: June 1-2, 1999
Conference Location: Delft, NL
Conference Title: TEMPMEKO
Pub Type: Conferences
absolute detectors, ITS-90, pyrometry, radiation temperature, spectral irradiance