COMPARISON OF LUMINOUS-INTENSITY SCALES BASED ON TRAP DETECTORS AND INCANDESCENT LAMPS

New luminous-intensity scales have been developed in Finland and Swede n based on silicon trap detectors having responsivities compared with an absolute cryogenic radiometer at a wavelength of 543,516 nm. The lo w reflectance of the trap device makes it possible to use a V (lambda) filter in conjunction with the trap where the filter is separately ch aracterized in transmittance. The new scales were compared with the sc ale currently in use in Sweden, which is based on incandescent lamps c alibrated by the Bureau International des Poids et Mesures (BIPM). The agreement of the scales is generally within +/- 1 %. The Finnish scal e was typically 0,2 % to 0,6 % below the BIPM-based scale, and the tra p-based scale of Sweden is typically 0 % to 0,5 % below the BIPM-based scale when compared at a measurement distance of 4 m. Different sizes of aperture and different distances to the source showed variations u p to +/- 1 %. The transmittances of the V (lambda) filters were measur ed separately by the two institutes and showed an agreement better tha n 0,1 % in the colour-correction factor.