As a part of the ongoing BIPM key comparison BIPM.EM-K11.b, a comparison of the 10 V voltage reference standards of the BIPM and the National Metrology Laboratory (NML), Dublin, Ireland, was carried out from April to May 2009. Two BIPM Zener diode-based travelling standards (Fluke 732B), BIPM_A (SN:7480002) and BIPM_C (SN:7195014), were transported by freight to NML. The NML measurements were carried out by comparison with the mean of the NML voltage standard.

The output EMF of each travelling standard, at its 10 V output terminals, was measured by comparison with the NML voltage standard, which comprises ten commercially-produced Zener diode-based electronic voltage standards.

At the BIPM, the traveling standards were calibrated with the Josephson Voltage Standard. Results of all measurements were corrected for the dependence of the output voltages on internal temperature and ambient pressure.

The comparison result is very satisfactory and shows that the voltage standards maintained by the NML and the BIPM were equivalent, within their stated expanded uncertainties, on the mean date of the comparison.

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 CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).