Eutectic Ga-In Melting-Point Blackbody for Radiation Thermometry

Abstract

The Radiation Thermometry Group at the Centro Nacional de Metrología (CENAM) is presently working with low-temperature fixed-point blackbodies to study their suitability for calibration and verification of radiation thermometers. The International Temperature Scale of 1990 specifies two fixed points in the 0 ºC to 30 ºC temperature range: the triple point of water and the melting point of gallium. We designed a eutectic Ga-In melting-point blackbody that could serve as a good candidate as a third fixed-point in the middle of those fixed points. The measured radiance temperature of the eutectic Ga-In melting-point blackbody was 15.67 ± 0.10 ºC (k = 1).