International comparison of the illuminance responsivity scales and units of luminous flux maintained at the HUT (Finland) and the NIST (USA)
نویسنده
چکیده
An international comparison has been conducted to compare the illuminance responsivity scales (A/lx) and the units of luminous ux (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 ux 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 ux comparison. The ratio of the measured illuminance responsivity values (HUT/NIST) was 0.9992 with an expanded uncertainty of 0.0013, and the ratio of the measured luminous ux values was 1.0006 with an expanded uncertainty of 0.0018. The relative expanded uncertainties of the agreement of the units, including the uncertainties of the realizations of the units as well as the uncertainty of the comparison, were 0.0047 and 0.0101, respectively.
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