CIPM MRA COMPARISON REPORTS

A comparison of the Josephson voltage standards (JVSs) of the Bureau International des Poids et Mesures (BIPM) and the Istituto Nazionale di Ricerca Metrologica (INRiM), Italy, was carried out in March 2026 at the level of 1  V and 10 V. For this comparison, the transportable JVS of the BIPM was brought to INRiM. For this exercise, options I and II of the BIPM.EM-K10 comparison protocol were applied. Option I required the BIPM to provide a reference voltage for measurement by INRiM using its Josephson standard with its own measuring device. Option II required INRiM to provide a reference voltage for measurement by the BIPM using its JVS together with an analog detector and associated measurement loop.
The final results were in excellent agreement with a relative voltage difference of a few parts in 10¹¹ and a total combined relative standard uncertainty of a few parts in 10¹⁰ at 1  V and a few parts in 10¹¹ at 10  V.

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).