TEMPERATURE COEFFICIENTS OF TOPCON RADIATION THERMOMETERS
− The ambient or instrument temperature affects the outputs of a standard radiation thermometer through various parts such as a detector, a feedback resistance and an interference filter. Usually the output was corrected by one coefficient assuming the linear dependence. If the filter wavelength changes, the dependence is different at each target temperature. We measured the temperature coefficients of Topcon radiation thermometers at different target temperatures and found the target temperature dependence as well as the feed back resistance dependence. Therefore a high stability radiation thermometer requires controlling the detector, filter and amplifier temperatures.
Calibration and characterization of Chino 900 nm silicon narrow-band radiation thermometer
This paper describes the calibration and characterization of the Chino 900 nm standard radiation thermometer, IR-RST-90 W. The gain ratio, fixed-point calibrations, spectral responsivity, nonlinearity, size-of-source effect, distance effect, zero-offset stability and temperature drift were measured. Some problems were found for this thermometer regarding the out-of-band suppression, the size-of-source effect and the temperature drifts. A new type radiation thermometer was manufactured for improving the quality to use as a standard radiation thermometer.
International comparison of radiation temperature scales among five national metrological laboratories using a transfer radiation thermometer
Round-robin measurements with a transfer standard radiation thermometer were organized by the NRLM in the framework of a three-year joint research agreement with the NIST, the IMGC and the PTB: the NPL also took part in this exercise. The aim of the study was to assess the mutual traceability of the ITS-90 temperature scales established by the different laboratories in the high-temperature range (above 1000 °C). The thermometer was a monochromatic (0,65 µm) silicon-detector thermometer belonging to the NRLM. It was circulated in the period from May to July 1993 and was calibrated by all the participants against their local reference thermometers. The temperature interval from 1000 °C to 2000 °C was covered by all the participants, but some extended the range down to 800 °C or up to 2700 °C. The results indicate that all the calibrations agree to within 0,5 °C at 1000 °C and to within 2 °C at 2000 °C.