A Precise Low Temperature dc Ratio Transformer

Harvey, I K

doi:10.1063/1.1685508

Cited by 183 publications

(57 citation statements)

References 9 publications

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“…L'un des points forts du laboratoire est la maîtrise d'un outil métrologique appelé « comparateur cryogénique de courants continus (CCC) » [35]. Il s'agit d'un transformateur de flux dont la particularité ré-side dans le fait que le gain d'amplification du courant est connu avec une incertitude très faible [36].…”

Section: Les Enjeux De L'expérience Du Triangle Métrologique Quantiqueunclassified

TRIMET : fermeture du triangle métrologique quantique à un niveau d'incertitude relative de 10–6

Feltin¹,

Steck²,

Devoille³

et al. 2011

R. franç. métrol.

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RésuméNous présentons les principaux résultats obtenus dans le cadre du projet ANR-TRIMET dont l'objectif était la fermeture du triangle mé-trologique quantique (TMQ) à un niveau d'incertitude relative de 10 −6 . L'expérience du TMQ consiste à réaliser une loi d'Ohm en utilisant les trois effets quantiques impliqués en métrologie électrique : l'effet Josephson (EJ), l'effet Hall quantique (EHQ) et l'effet tunnel à un élec-tron (SET). Le but est de vérifier la cohérence des constantes phéno-ménologiques K J , R K , Q X , associées respectivement à ces trois effets et théoriquement exprimées en fonctions des deux constantes fondamentales, h et e (constante de Planck et charge élémentaire). Cette expé-rience est une contribution importante à une redéfinition du Système international d'unités (SI). Nous montrons aussi que la fermeture du TMQ permettra la mise en oeuvre d'une nouvelle détermination de la charge élémentaire, e.

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Section: Les Enjeux De L'expérience Du Triangle Métrologique Quantiqueunclassified

TRIMET : fermeture du triangle métrologique quantique à un niveau d'incertitude relative de 10–6

Feltin¹,

Steck²,

Devoille³

et al. 2011

R. franç. métrol.

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“…Until now, the use of QHE at the best level is limited to important NMIs because of the need of quite complex and expensive equipment based on the cryogenic current comparator [25][26][27] (CCC). Henceforth, samples characterized by a low density of electrons and a high mobility may offer a first simplification of the measurement system since they work with lower magnetic field and higher temperature 28,29 . However, the CCC stays essential if using classical Hall bars supplied by currents limited to some tens of µA.…”

Section: Introductionmentioning

confidence: 99%

R K /100 and RK/200 quantum Hall array resistance standards

Poirier

Bounouh

Hayashi

et al. 2002

Journal of Applied Physics

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It is theoretically possible to combine several Hall bars in arrays to define new quantum standards with perfectly quantized resistance values. We have thus, for the first time, developed and fabricated novel Quantum Hall Array Resistance Standards (QHARS) made of a large number N (N=100, 50) of Hall bars placed in parallel using a triple connections technique. The Hall resistance of these quantum standards is found to be very well quantized. On the i=2 Hall plateau, the resistance of specific good arrays stays equal to R K /2N within 5 parts in 10 9 for supplying currents up to 2 mA at a temperature of 1.3 K. The mean longitudinal resistance of the Hall bars which constitute the arrays has been determined through the analysis of the array equivalent electrical circuit. This measurement shows that the carrier transport in the Hall bars is dissipationless. This work therefore demonstrates the efficiency of the multiple connections technique and consequently that QHARS are likely to extend the QHE metrological applications.

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“…The CCC was invented by Harvey in 1972 [20]. The principle rests on Amp re's law and perfect diamagnetism of the superconductor in the Meissner state.…”

Section: Principle Of the CCCmentioning

confidence: 99%

“…By extending the concept of the sensitive current detector as proposed by Harvey in his original paper, one can use the CCC as a low-current amplifier with two characteristics never reached by any conventional device [20]. As shown below, the CCC may exhibit a current resolution around 1 fA/Hz 1/2 or less over the white noise frequency range.…”

Section: Introductionmentioning

confidence: 99%