1. High-Transmission Filters for Realizing Gray-Body Radiators.
- Author
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Ishii, J. and Yamada, Y.
- Subjects
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GREY body (Physics) , *BLACKBODY radiation , *HEAT transfer , *TRANSITION temperature , *THERMAL expansion , *THERMODYNAMIC state variables , *THERMAL properties , *THERMOPHYSICAL properties - Abstract
Calibration of infrared radiation thermometers at non-unity emissivity settings is a poorly solved problem for establishment of traceability to meet user needs, for instruments with both fixed and variable emissivity setting functions. A variable-temperature gray-body radiator having a constant value of emissivity independent of both wavelength and temperature can be a perfect tool for the calibration purpose. In this paper, two types of high-transmittance optical neutral density filters, one utilizing a rotating-sector optical chopper, and another of a wire-mesh type, are shown to perform well with a precise transmittance between 90 % and 100 % in the wide infrared wavelength range. These optical filters in combination with a blackbody cavity traceable to ITS-90 can realize reliable gray-body radiation. These methods are applied successfully to several models of infrared thermometers operated in the emissivity correction mode. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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