Preliminary measurements of the precise comparison between a radiation thermometer and a platinum resistance thermometer

This paper describes the preliminary measurements of the precise comparison between a radiation thermometer and a platinum resistance thermometer (PRT). The aim of this work is to measure the resistance - temperature relation of standard platinum resistance thermometers at temperatures above the present upper limit (961.78degC) of PRTs. The comparison furnace is placed in horizontal orientation, and a graphite block is placed in the center as a comparison block. In this paper, preliminary measurement results for the evaluation of the uncertainty in the comparison measurement are reported. First, the results of the comparison using the design configuration determined in our previous paper are reported. Upon the measurements of three independent experimental rounds, we suspected that the design of the comparison block needed some improvements. We re-designed the comparison block, and also report the comparison results obtained using this improved version.