An International Intercomparison of Spectral Irradiance Scales

Abstract

An intercomparison among the spectral irradiance scales of eight national standardizing laboratories has been carried out by the Electrotechnical Laboratory of Japan. Four tungsten-filament, quartz-bromine lamps with clear of frosted bulbs were distributed to each of the participants. The values of spectral irradiance, produced by the lamps at a specified point were measured at seven wavelengths from 300 to 800 nm. The comparison shows that most of the laboratories agreed within ±1%, except for the wavelengths of 300, 350 and 800 nm. It is suggested that further study is necessary at those wavelengths.