Abstract
As an infrared radiation standard for the calibration of radiation thermometers, blackbody radiation was realized by utilizing the phase-equilibrium between solidus and liquidus of antimony. For this purpose, two kinds of blackbodies, a precision-type blackbody radiator for a fundamental standard and a blackbody cell for a simple practical standard, were prepared as a trial and experimented. The both blackbodies were made of high purity graphite and antimony with a purity of higher than 99.999% was sealed in it.
In this paper, the detailed structures of the blackbody radiators are described and the practical method for realizing blackbody radiation at the phase-equilibrium of antimony is reported. In addittion, their reproducibility and the various factors which are presumably responsible for the systematic errors, such as the effectiv emissivity of cavities, the inner wall temperature gradient of them, the stray radiation effect in the measuring system, etc. have been investigated and evaluated.
As a result, it has been concluded that as to the over-all accuracies, the precision-type blackbody as a fundamental standard can be expected to provide higher accuracies than 0.1K and even the blackbody cell as a practical standard can provide enough accuracies of about ±0.2K for industrial use.
