Radiometic Comparison Between a National Laboratory and an Industrial Laboratory

One of the disciplines that Fluke–Hart Scientific has is radiometric calibration. Part of this program involves use of a radiation thermometer with a pyroelectic detector. It is used as a radiometric transfer standard between a set of liquid-bath variable temperature blackbodies and a flat-plate infrared (IR) calibrator. The flat-plate calibrator is designed for use in the calibration of handheld IR thermometers. The traceability of the variable temperature blackbodies is realized by contact thermometry through the National Institute of Standards and Technology (NIST). A verification of these blackbodies is a comparison between a calibration done by the Radiance Temperature Laboratory at NIST and the blackbodies at Fluke–Hart Scientific. This comparison uses a transfer radiation thermometer (TRT) as a check standard. It would be more desirable to use radiometric traceability as an indication of the blackbodies’ radiometric temperature. However, contact thermometry provides much better uncertainties. These uncertainties are needed for the radiometric transfer from the blackbodies to the flat-plate calibrators. Thus, the NIST radiometric calibration of the TRT is used for verification of normal equivalence. This article discusses Fluke–Hart Scientific’s blackbody traceability. It covers the Fluke–Hart Scientific and the NIST radiometric calibration procedures. It discusses the radiometric uncertainty budgets at both Fluke–Hart Scientific and at NIST. It then discusses the results of this comparison and analyzes the results. The comparison is in the temperature range of −15 °C to 500 °C. It showed a normal equivalence of less than 1.00 at all points. The article concludes with a set of future actions to ensure quality in Fluke–Hart Scientific’s radiometric calibration program.

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