Comparison of the radiation temperature scales between MIKES and PTB

The radiation temperature scales of PTB and MIKES were compared in the range of 1570–2770 K using four filter radiometers of MIKES, one filter radiometer of PTB, and linear radiation thermometers of both MIKES and PTB. The agreement was partial: two filter radiometers and the linear radiation thermometer of MIKES agreed well with the equipment of PTB, while two filter radiometers deviated from the other equipment. To get a deeper understanding of the reasons of the deviation, the results were studied in terms of both temperature and radiance. The deviation was found constant in terms of radiance. A correction factor was calculated for the radiance level with help of a temperature fixed-point calibration. The use of the correction factor improved the results.