Intercomparison of Photometric Units Maintained at NIST (USA) and PTB (Germany),1993

摘要

A bilateral intercomparison of photometric units between NIST, USA and PTB,Germany has been conducted to update the Knowledge of the relationship between the Photometric units diseminated in each country. The luminous intensity unit (cd) and the luminous flux unit (lm) maintained at both laboratories are compared by circulating transfer standard lamps. Also, the photometric responsivity s(sub v) is compared by circulating a lambda-corrected detector with a built-in current-to-voltage converter. The results show that the difference of luminous intensity unit between NIST and PTB, (PTB-NIST)/NIST, is 0.2% with a relative expanded uncertainty (coverage factor k=2) of 0.24%. The difference is reduced significantly from that at the 1985 CCPR intercomparison (0.9%).