Comparison of luminous-intensity scales based on trap detectors and incandescent lamps

New luminous-intensity scales have been developed in Finland and Sweden based on silicon trap detectors having responsivities compared with an absolute cryogenic radiometer at a wavelength of 543,516 nm. The low reflectance of the trap device makes it possible to use a V (lambda) filter in conjunction with the trap where the filter is separately characterized in transmittance. The new scales were compared with the scale currently in use in Sweden, which is based on incandescent lamps calibrated by the Bureau International des Poids et Mesures (BIPM). The agreement of the scales is generally within +/- 1 %. The Finnish scale was typically 0,2 % to 0,6 % below the BIPM-based scale, and the trap-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 up to +/- 1 %. The transmittances of the V (lambda) filters were measured separately by the two institutes and showed an agreement better than 0,1 % in the colour-correction factor.