10 Volt automated direct comparison of two cryocooled programmable Josephson voltage standards

Rüfenacht, Alain; Tang, Yi-hua; Fox, Anna E.; Dresselhaus, Paul D.; Burroughs, Charles J.; Schwall, Robert E.; Benz, Samuel P.

doi:10.1109/cpem.2016.7540474

Cited by 4 publications

(3 citation statements)

References 4 publications

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“…The accuracy of 10 V PJVS has been demonstrated by comparison to 10 V CJVS; no significant difference between the voltage standards were measured within 1.2 part in 10 10 [133] and 2.6 parts in 10 10 [134] (k=2). The recent comparison of two cryocooled 10 V PJVS [135] illustrates the advantages of the PJVS over the CJVS. The complete automation and synchronisation of both systems allow voltage reversals over very long measurement time (28 h) and enable the use a very sensitive null detector.…”

Section: S P S M U N P L N R C C E M N M I J B E V I N E T I N M Imentioning

confidence: 99%

The ampere and the electrical units in the quantum era

Poirier

Djordjevic

Schopfer

et al. 2019

Comptes Rendus. Physique

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By fixing two fundamental constants from quantum mechanics, the Planck constant h and the elementary charge e, the revised Système International (SI) of units endorses explicitly quantum mechanics. This evolution also highlights the importance of this theory which underpins the most accurate realization of the units. From 20 May 2019, the new definitions of the kilogram and of the ampere, based on fixed values of h and e respectively, will particularly impact the electrical metrology. The Josephson effect (JE) and the quantum Hall effect (QHE), used to maintain voltage and resistance standards with unprecedented reproducibility since 1990, will henceforth provide realizations of the volt and the ohm without the uncertainties inherited from the older electromechanical definitions. More broadly, the revised SI will sustain the exploitation of quantum effects to realize electrical units, to the benefit of end-users. Here, we review the state-of-the-art of these standards and discuss further applications and perspectives.

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Section: S P S M U N P L N R C C E M N M I J B E V I N E T I N M Imentioning

confidence: 99%

The ampere and the electrical units in the quantum era

Poirier

Djordjevic

Schopfer

et al. 2019

Comptes Rendus. Physique

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“…Following the successful implementation of programmable Josephson voltage standards (PJVS) at 10 V in recent years [7][8][9], quantum voltage reference systems based on a non-hysteretic JJ have progressively replaced conventional Josephson voltage standard (CJVS) systems based on metastable, zero-crossing quantum voltage steps as primary voltage standards at the institutes. Further improvement was accomplished by integrating PJVS devices successfully with liquid-free cryogenic mechanical coolers [10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Direct DC 10 V comparison between two programmable Josephson voltage standards made of niobium nitride (NbN)-based and niobium (Nb)-based Josephson junctions

et al. 2018

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BIPM's new transportable programmable Josephson voltage standard (PJVS) has been used for an on-site comparison at the National Metrology Institute of Japan (NMIJ) and the National Institute of Advanced Industrial Science and Technology (AIST) (NMIJ/AIST, hereafter called just NMIJ unless otherwise noted). This is the first time that an array of niobium-based Josephson junctions with amorphous niobium silicon Nb x Si 1−x barriers, developed by the National Institute of Standards and Technology 4 (NIST), has been directly compared to an array of niobium nitride (NbN)-based junctions (developed by the NMIJ in collaboration with the Nanoelectronics Research Institute (NeRI), AIST). Nominally identical voltages produced by both systems agreed within 5 parts in 10 12 (0.05 nV at 10 V) with a combined relative uncertainty of 7.9 × 10 −11 (0.79 nV). The low side of the NMIJ apparatus is, by design, referred to the ground potential. An analysis of the systematic errors due to the leakage current to ground was conducted for this ground configuration. The influence of a multi-stage low-pass filter installed at the output measurement leads of the NMIJ primary standard was also investigated. The number of capacitances in parallel in the filter and their insulation resistance have a direct impact on the amplitude of the systematic voltage error introduced by the leakage current, even if the current does not necessarily return to ground. The filtering of the output of the PJVS voltage leads has the positive consequence of protecting the array from external sources of noise. Current noise, when coupled to the array, reduces the width or current range of the quantized voltage steps. The voltage error induced by the leakage current in the filter is an order of magnitude larger than the voltage error in the absence of all filtering, even though the current range of steps is significantly decreased without filtering. Bureau International des Poids et Mesures 4 Contribution of the US Government, not subject to copyright.

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“…Keeping the measurement circuit floating from ground reduces the influence of the leakage current induced by the bias current electronics and minimizes the error on the voltage difference measurement (Type-B contribution in the uncertainty budget). In addition, leaving the measurement circuit floating from ground slightly reduces the noise measured by the NVM in our measurement setup [40]. For these reasons, the floating measurement circuit configuration was chosen for generating the final results presented in this paper.…”

Section: Measurement Circuit Floating From the Earth Ground Potentialmentioning

confidence: 99%

Automated direct comparison of two cryocooled 10 volt programmable Josephson voltage standards

et al. 2018

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We have performed direct dc comparisons between two cryocooled 10 V programmable Josephson voltage standards. Utilizing an automated synchronization scheme for the voltage reversals enables use of a high-sensitivity analog null detector on its 10 µV range. No switches or manual operations are necessary to protect the null detector from overload signals. The agreement measured between the two voltage standards at 10 V is 9 parts in 1012 with a relative combined uncertainty of 29 pV V−1 (k = 2 coverage factor). Since both systems can be operated floating from ground, various grounding configurations of the measurement circuit were investigated to evaluate possible leakage current paths to ground. Comparing the two systems under various grounding conditions enables minimization of leakage-current errors, optimization of system performance by revealing leakage-limiting components, and verification of key elements in the uncertainty budget for the measurement method.

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10 Volt automated direct comparison of two cryocooled programmable Josephson voltage standards

Cited by 4 publications

References 4 publications

The ampere and the electrical units in the quantum era

The ampere and the electrical units in the quantum era

Direct DC 10 V comparison between two programmable Josephson voltage standards made of niobium nitride (NbN)-based and niobium (Nb)-based Josephson junctions

Automated direct comparison of two cryocooled 10 volt programmable Josephson voltage standards

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