International Comparison of the Illuminance Responsivity Scales and Units of Luminous Flux Maintained at the HUT (Finland) and the NIST (USA)
J Hovia, P Toivanen, E Ikonen, Yoshi Ohno
An intercomparison has been conducted to compare the illuminance responsivity scales (A/lx) and the luminous flux units (lm) maintained at the National Institute of Standards and Technology (NIST, USA) and the Helsinki University of Technology (HUT, Finland). Both laboratories realize the illuminance unit by absolutely calibrated photometers and the luminous flux unit by the absolute integrating sphere method. Standard photometers were used as transfer standards for the illuminance responsivity comparison, and standard lamps in the luminous flux comparison. The ratio of the measured illuminance responsivity values (HUT/NIST) was 0.9992 with an expanded uncertainty (k=2) of 0.0014, and the ratio of the measured luminous flux values was 1.0006 with an expanded uncertainty (k=2) of 0.0018. The relative expanded uncertainties of the agreement of the units, including the uncertainties of the realizations of the units and the uncertainty of the comparison, were 0.0045 and 0.0093, respectively.
illuminance, illuminance responsivity, intercomparison, luminous flux, national standard
, Toivanen, P.
, Ikonen, E.
and Ohno, Y.
International Comparison of the Illuminance Responsivity Scales and Units of Luminous Flux Maintained at the HUT (Finland) and the NIST (USA), Metrologia
(Accessed December 3, 2023)