The Determination of the Thermodynamic Temperatures of Thermometry Fixed Points in the Range 660 °C to 1064 °C

The thermodynamic temperatures of the silver, gold and copper-silver eutectic fixed points were measured with a photoelectric pyrometer relative to an aluminium point of 660.302 °C. The values obtained were (961.744 ± 0.055) °C, (1064.145 ± 0.060) °C and (779.583 ± 0.060) °C respectively. Although the final uncertainty of the copper-silver eutectic was similar to that of the other two, the effort necessary to obtain it was much greater and it is not recommended as a major reference point for use in photoelectric pyrometry.