Comparison of the Josephson voltage standards of the LNE and the BIPM (part of the ongoing BIPM key comparison BIPM.EM-K10.b)

Abstract

A comparison of the 10 V Josephson array voltage standard of the Bureau International des Poids et Mesures (BIPM) was made with that of the Laboratoire National de Métrologie et d'Essais (LNE), France, in December 2007. The results are in very good agreement and the estimated combined relative standard uncertainty is 1.1 parts in 1011.This comparison is the first to follow the new version of the technical protocols for BIPM.EM-K10a & b (Options A and B1), which were reviewed by the experts designated during the 23rd CCEM (2007) to be members of the CCEM Support Group for BIPM direct on-site Josephson comparisons. The difference with the previous version of the protocol is the insertion of the following rule: "When a significant improvement is obtained during the comparison both the initial and the final results are added to the KCDB with a note, but only the final result appears on the graph of results."This article describes the technical details of the experiments which were carried out to achieve the final result of the comparison.1 Option A is the scheme where the BIPM measures the JVS of the participant with its measurement setup. Option B is the other way around.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).

The ampere and the electrical units in the quantum era

“…Fig.11 presents the results of the international Key comparison BIPM EM K10b [118]. It shows that for most of the participants, the degree of equivalence, which is defined as the voltage difference with respect to the BIPM value associated with the expanded uncertainty U i corresponding to a coverage factor k = 2, is below 5 parts in 10 10 [119] and some are at a few parts in 10 11 [120]. The wide dissemination of CJVS is ensured by the commercialization of these standards by two hightech companies specialized in superconducting electronics [121,122].…”

A 10 V programmable Josephson voltage standard and its applications for voltage metrology

“…The PJVS cryoprobe has about 10 times higher leakage resistance than that of the conventional cryoprobe because no capacitive filter is installed in the PJVS probe. The leakage resistance of the PJVS bias electronics to ground was measured using a method described previously [23], and found to be 1.5 × 10 10 . The leakage resistance to the ground at the various nodes of the voltage measurement loop (such as from the conventional JVS precision voltage leads and DVM to the ground) is five times this value (or more).…”

Conception et applications d’un étalon Josephson programmable de 1 V au LNE

“…11). La configuration de la chaîne de mesure est quasiment similaire à la configuration utilisée lors de la comparaison BIPM-EM.K10b [8]. Les deux dispositifs Josephson étaient connectés en série-opposition.…”

“…L'incertitude combinée tient compte des composantes d'incertitude associées à la fréquence micro-onde, au détecteur de zéro et aux résistances de fuites [8,17]. Ces résultats démontrent que le nouveau système peut être utilisé comme référence primaire de tension continue par le laboratoire d'étalonnage électrique.…”

“…La figure 1 tirée de la référence [7] montre les résultats des comparaisons internationales menées par le BIPM depuis plus de dix ans. Le résultat obtenu en 2007 par le LNE [8] courant) [9], ou celui d'un voltmètre numérique (gain, linéarité). Par conséquent, ces réseaux sont peu adaptés pour effectuer des prestations d'étalonnage courantes telles qu'elles existent dans les laboratoires de métrolo-gie industriels.…”