Bilateral comparison of 1.018 V and 10 V standards between the BIM (Bulgaria) and the BIPM (BIPM.EM-K11.a and b)

Main text As part of the ongoing BIPM key comparison BIPM.EM-K11.a and b, a comparison of the 1.018 V and 10 V voltage reference standards of the BIPM and the Bulgarian Institute of Metrology, BIM, was carried out in April 2019. The objective for BIM in participating in this comparison was to demonstrate the international equivalence of its DC voltage measurement results and to support the calibration and measurement capabilities (CMCs) published in the Key Comparison Database of the BIPM (KCDB). Two BIPM Zener diode-based travelling standards (Fluke 732B) were shipped to Sofia in March 2019. At the BIPM, the reference standard for DC voltage is a primary voltage standard based on the Josephson effect, developed by the BIPM. The output electromotive force (EMF) of each travelling standard was measured against the Josephson Voltage Standard (JVS) before and after the measurements at BIM. At the BIM, the reference standard is a commercial JVS. The final result of the comparison is presented as the difference between the values assigned to DC voltage standards by BIM, at the level of 1.018 V and 10 V, at BIM, U BIM, and those assigned by the BIPM, at the BIPM, U BIM, at the reference dates of the 26 th of March 2019. U BIM - U BIM = - 0.01 µV; uc = 0.02 µV, at 1.018 V U BIM - U BIM = + 0.30 µV; uc = 0.09 µV, at 10 V where uc is the combined standard uncertainty associated with the measured difference. 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 https://www.bipm.org/kcdb/ . 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).