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. 1973 Apr 1;12(4):810-7.
doi: 10.1364/AO.12.000810.

Active cavity radiometer

R C Willson

Active cavity radiometer

R C Willson. Appl Opt. .

Abstract

The active cavity radiometer (ACR) is a pyrheliometer that accurately defines the absolute radiation scale. The physics of the pyrheliometric method and the ACR approach to this method are presented in detail. A mathematical abstraction of the method is generated through a quasi-equilibrium analysis of the power balance of the ACR's cavity detector. An error analysis is carried out on the quasi-equilibrium equation to determine the uncertainties of ACR measurements relative to the absolute radiation scale. The uncertainty of ACR measurements as a function of irradiance level is presented in graphical form.

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