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Proceedings Paper

Total radiant exitance measurements
Author(s): Norman H. Macoy
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Paper Abstract

A room temperature electrical substitution radiometer (ESR) or electrically calibrated null radiometer (ECNR) has been employed to determine the total radiant exitance of a high temperature secondary standard blackbody to illustrate the convenience of a room temperature ESR. Additionally, routine experimental precisions of ±0.13 to 0.05 percent (type A errors) and a derived absolute accuracy of ±0.24 percent (type B errors) for the Stefan-Boltzmann constant determination and ±0.2deg for the blackbody temperature determination have been demonstrated. From the blackbody radiator's temperature, the familiar Stefan-Boltzmann constant is measured within 0.11 percent absolute to the currently accepted value of 5.67051 x 1012 W-cm-2-K-4. Alternatively by applying the accepted Stefan-Boltzmann constant value, the radiator's temperature is derived and shown to be within 0.2 degree at 692.73 K, the zinc freezing point standard and within 0.2 degree at 933.62 K, the aluminum freezing point standard. The uncertainty of the secondary standard blackbody is ±0.2 K following radiometric comparison to zinc and aluminum primary standard blackbodies. By way of introduction, the genesis of 25 determinations of the Stefan-Boltzmann constant, spanning a period of 86 years, is presented to illustrate the evolution of technical advances in analytical methods, the quality of equipment, and refined accuracy.

Paper Details

Date Published: 1 September 1990
PDF: 25 pages
Proc. SPIE 1311, Characterization, Propagation, and Simulation of Infrared Scenes, (1 September 1990); doi: 10.1117/12.21817
Show Author Affiliations
Norman H. Macoy, Hughes Danbury Optical Systems, Inc. (United States)

Published in SPIE Proceedings Vol. 1311:
Characterization, Propagation, and Simulation of Infrared Scenes
Milton J. Triplett; Wendell R. Watkins; Ferdinand H. Zegel, Editor(s)

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