Spectral irradiance calibrations at the National Research Council of Canada (NRC)

Abstract

The basis of accurate photometric evaluations of light sources is provided by accurate spectral measurements under specified geometric conditions. This accuracy is ensured by traceable, internationally recognized absolute spectroradiometric scales. National Metrology Institutes (NMIs) develop primary-level spectroradiometric facilities and verify these absolute optical measurements through international comparisons with other NMIs. This paper describes the NRC facilities, standards and the results of recent international CCPR (Consultative Committee for Photometry and Radiometry) key comparisons of spectral irradiance measurements. It concludes with a brief update on our plans for using our new high-temperature blackbody as the basis for a new spectroradiometric scale.

Keywords:

• photometry
• spectral irradiance
• calibration chain
• standard source
• international comparison
• high temperature blackbody

Acknowledgements

The author would like to thank D.S. Gignac and F.A. Gauthier for their assistance in assembling the spectral irradiance equipment and performing many of the spectral measurements required for this work. He is grateful to Dr L.P. Boivin for many discussions concerning the absolute detector measurements and associated calibration chains. The assistance of Dr J.C. Zwinkels in the preparation of this paper is much appreciated.