NIST Radiance Temperature and Infrared Spectral Radiance Scale at Near-Ambient Temperatures
Sergey Mekhontsev, V B. Khromchenko, Leonard Hanssen
The realization and the dissemination of spectral radiance and radiance temperature scales in the temperature range of -50 C to 250 C and spectral range of 3 m to 13 m at the National Institute of Standards and Technology is described. The scale is source-based and is established using a suite of blackbody radiation sources, the emissivity and temperature of which have been thoroughly investigated. The blackbody emissivity was measured using the complementary approaches of modeling, reflectometry and the intercomparison of spectral radiance of sources with different cavity geometries and coatings. Temperature measurements are based on platinum resistance thermometers, and on the direct use of the phase transition points of pure metals. Secondary sources are calibrated using reference blackbody sources, a spectral comparator, a controlled background plate and a motion control system. Included experimental data on performance of transfer standard blackbodies indicates need in development of a recommended practice for their specification and evaluation. Introduced services allow to establish a nationwide uniformity in metrology of near-ambient thermal emission sources, providing traceability in spatially and spectrally resolved radiance temperature, spectral radiance and background-corrected effective emissivity.
, Khromchenko, V.
and Hanssen, L.
NIST Radiance Temperature and Infrared Spectral Radiance Scale at Near-Ambient Temperatures, International Journal of Thermophysics
(Accessed September 27, 2023)