Reducing uncertainty in practical radiation thermometer calibration based on proposed changes to the

The effect of changing calibration traceability for radiation thermometry from the current International Temperature Scale of 1990 (ITS-90) to a proposed SI based scale is investigated in the context of the dissemination of a radiation thermometer based high temperature scale from national measurement institute to calibration laboratory. It is shown that at temperatures up to 2500 °C the uncertainty in temperature scale realisation can be halved without changing the calibration laboratory methodology. Significant benefits are possible now, based on present ITS-90, in advance of any proposed changes. The requirements for a suitable radiation thermometer to achieve this are considered