A summary of the Planck constant determinations using the NRC Kibble balance

Wood, B.M.; Sánchez, C.; Green, R G; Liard, J.

doi:10.1088/1681-7575/aa70bf

Cited by 63 publications

(52 citation statements)

References 12 publications

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“…This value is in excellent agreement with the recommendations mentioned in [28], 0.91·10 -8 , and should be satisfactory to the existing mass standards community. In this way, the ability to predict the Planck constant value by using the comparative uncertainty allows us to improve our fundamental comprehension of the complex phenomenon as well as to apply this comprehension to the solution of specific problems.…”

Section: Applications Of µ Si For Plank Constant Measurementsupporting

confidence: 87%

Plank’s Constant: Evaluation of Measurement Uncertainty

Menin¹,

Expert²

2018

NHMP

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Abstract. In this article, we present a new metric called the comparative uncertainty, according to which the least achievable relative uncertainty is calculated when measuring the Planck constant. To calculate the comparative uncertainty, information theory is used. The optimizing criterion is the number of quantities considered in the model. Its calculation is possible due to the fact that any model contains a certain amount of information about the object under study. Comparative uncertainty can be verified by field trials or computer simulations within a specified range of changes of the Planck constant. The concept of introduced uncertainty is universal and can be recommended for estimating the accuracy of measurements in the study of physical phenomena and technological processes. Examples of application of the proposed approach are discussed.

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Section: Applications Of µ Si For Plank Constant Measurementsupporting

confidence: 87%

Plank’s Constant: Evaluation of Measurement Uncertainty

Menin¹,

Expert²

2018

NHMP

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“…Adoption of the theoretical relationships K J = 2e/h and R K = h/e 2 in the SI provides a direct link between mass and Planck constant according to m = h A 4gv , where A is a quantity involving Josephson frequencies, number of Josephson junctions and Hall plateau index. After participating in h determinations [99], it is now a question of using Kibble's balances, notably those having participated in the 49 determination of h from NIST [263], NRC [264] and LNE ( fig.29b) [265], to calibrate mass standards with a 10 −8 relative uncertainty from the Planck constant value[98] h = 6.62607015 × 10 −34 J.s. This extension of the application of solid-state quantum effects beyond electrical metrology is to benefit from the user-friendly graphene-based quantum resistance standard and cryogen-free cooling techniques.…”

Section: The Kibble Balance or The Quantum Kilogrammentioning

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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“…For the magnet discussed here, the magnetic field in the gap is (mostly) horizontal and the gap is oriented vertically. In (6), t denotes the horizontal distance from the edge of the disk. It needs to be replaced by the vertical distance from the end of the gap d/2 − |z|.…”

Section: Discussionmentioning

confidence: 99%

A Simple Improvement for Permanent Magnet Systems for Kibble Balances: More Flat Field at Almost No Cost

Schlamminger

Wang

2020

IEEE Trans. Instrum. Meas.

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Permanent magnets together with yokes to concentrate the magnetic flux into a cylindrical airgap are widely employed in Kibble balances. These experiments require a uniform magnetic flux density along a vertical path, typically a substantial fraction of the length of the air-gap. Fringe fields that are present at both ends of the air-gap limit the region where the flux density does not change more than a certain relative fraction (here: 5 × 10 −4 ) of the flux density in the center of the magnet system. By simply adding an iron ring with a rectangular cross-section to the inner yoke at each end of the air gap, the effects of the fringe fields can be counteracted, and, hence, the length of the region, where the flux density remains within a given tolerance band is increased. Compared to the alternative, employing a taller magnet, the proposed method yields a magnet system with an extended region of a uniform field without significantly increasing the mass of the magnet system. Potential applications include compact and table-top Kibble balances. We investigate possible adverse effects on the performance of the magnet system caused by the additional rings: magnetic field strength, coil-current effect, and a dependence of the radial field on the radial position in the field. No substantial disadvantage was found. Instead, the method presented here outperformed previously suggested methods to improve the radial dependence of the radial field, e.g., shorter outer yoke. In summary, adding rings to the inner yoke improves the uniformity of the field without a detrimental effect to function, cost, and form factor of the magnet system.

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A summary of the Planck constant determinations using the NRC Kibble balance

Cited by 63 publications

References 12 publications

Plank’s Constant: Evaluation of Measurement Uncertainty

Plank’s Constant: Evaluation of Measurement Uncertainty

The ampere and the electrical units in the quantum era

A Simple Improvement for Permanent Magnet Systems for Kibble Balances: More Flat Field at Almost No Cost

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