Presented at The 8th Symposium on Temperature: Its Measurement and Control in Science and Industry, October 21 – 24, 2002, sponsored by NIST, ISA, and AIP:

The Spectropyrometer
A Practical Multi-wavelength Pyrometer

Abstract. An expert-system multi-wavelength pyrometer, commercially available since 1997 and using a spectrophotometer as its detector, has been able to overcome many well-known difficulties of pyrometry, including unknown, changing, and/or spectral dependence of emissivity as well as environmental absorption of radiation. In addition to a spectrophotometer and the usual optics, the instrument includes a computer which analyzes each measurement and then returns the temperature, the tolerance (a real-time measure of accuracy), and the signal strength (a quantity directly related to the emissivity at a chosen wavelength). The computer allows the input data, namely the thermal spectrum for each temperature measurement, to be saved. Accuracy to 0.10% is routinely achieved.

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