Bilateral comparison of 10 V standards between the NSAI–NML (Ireland) and the BIPM, February to March 2012 (part of the ongoing BIPM key comparison BIPM.EM-K11.b)

Abstract

As part of the on-going BIPM key comparison BIPM.EM-K11.b, a comparison of the 10 V voltage reference standards of the BIPM and the National Standards Authority of Ireland–National Metrology Laboratory (NSAI–NML), Dublin, Ireland, was carried out from February to March 2012. Two BIPM Zener diode-based travelling standards (Fluke 732B), BIPM_C (ZC) and BIPM_D (ZD), were transported by freight to NSAI-NML. At NSAI-NML, the reference standard for DC voltage at the 10 V level consists of a group of characterized Zener diode-based electronic voltage standards. The output EMF (electromotive force) of each travelling standard was measured by direct comparison with the group standard.At the BIPM the travelling standards were calibrated, before and after the measurements at NSAI–NML, with the Josephson voltage standard. Results of all measurements were corrected for the dependence of the output voltages on internal temperature and ambient atmospheric pressure.The final result of the comparison is presented as the difference between the value assigned to DC voltage standard by NSAI–NML, at the level of 10 V, at NSAI–NML, UNML, and that assigned by the BIPM, at the BIPM, UBIPM, at the reference date of 23 February 2012.UNML − UBIPM = +0.83 µV, uc = 1.35 µV, at 10 Vwhere uc is the combined standard uncertainty associated with the measured difference, including the uncertainty of the representation of the volt at the BIPM and at NSAI–NML, based on KJ-90, and the uncertainty related to the comparison.The final result is impacted by the anomalous offset between the NSAI–NML results for the two transfer standards. The reason for this offset hasn't been determined.However, the difference remains within the total combined standard uncertainty. Therefore, the comparison result shows that the voltage standards maintained by NSAI–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 (CIPM MRA).