Bilateral comparisons of luminous intensity using tungsten lamps as transfer standards and luminous responsivity using a photometer as transfer standard were carried out between the NMIA and the SPRING in November and December 2003. The NMIA acted as the pilot laboratory and provided the links to the key comparisons CCPR K3.a and CCPR K3.b.

The ratio of the measured luminous intensity (SPRING/NMIA) was 1.0010 with a combined standard uncertainty of 0.0038 and the ratio of the measured luminous responsivity (SPRING/NMIA) was 1.0008 with a combined standard uncertainty of 0.0035 (k = 1).

SPRING realised its new luminous intensity scale on a set of trap-photometers traceable to its cryogenic radiometer in January 2003. The new scale replaced the old one that was traceable to BIPM, and was used in this comparison. Based on the results of this comparison, it has been established that the degrees of equivalence of the SPRING's new units relative to the KCRV values from the 1997–98 CCPR key comparisons are 1.0003 ± 0.0033 for the unit of luminous intensity and 1.0017 ± 0.0030 for luminous responsivity (k = 1).

Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.

The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the Mutual Recognition Arrangement (MRA).