A New Standard for the Candela in the USSR

Abstract

A method of constructing the standard for the newly defined luminous intensity unit, the candela, in the USSR is described. The standard is based on a non-selective radiometer/black-body (BB) combination. The temperature of the radiating cavity of the BB is obtained by measuring spectral and integral components of radiation at two different temperatures. The radiometer conversion coefficient is not measured by a substituting winding, but with the help of the BB according to the Stefan-Boltzmann law. The relative spectral sensitivity of the radiometer is modified by the function V (λ) by means of a liquid filter. The unit of luminous intensity is then transferred by the photometer to the light-intensity-measuring lamps.