The BIPM Kibble Balance for the Realization of the Redefined Kilogram

Fang, Hao; Bielsa, Franck; Li, Shisong; Kiss, A.; Stöck, M

doi:10.1109/cpem.2018.8500899

Cited by 8 publications

(4 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interestingly, the change in profile is more linear over larger scales after the compensation is applied. For a Kibble balance operating with a single mode [10], [16], better linearity of the measurement trajectory simplifies the velocity profile fit in the data processing.…”

Section: Change Of the Coil-current Effectmentioning

confidence: 99%

“…At present, all ongoing Kibble balance experiments in the world have chosen permanent magnetic circuits to generate the necessary field required for the measurement [5]- [15]. A typical symmetrical design, which originated at the International Bureau of Weights and Measures (BIPM) [10], and has since been chosen widely by researchers at National Metrology Institutes (NMIs) [7], [11], [13], [15], is shown in Fig. 1.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

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

Schlamminger

Wang

2020

IEEE Trans. Instrum. Meas.

View full text Add to dashboard Cite

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.

show abstract

Section: Change Of the Coil-current Effectmentioning

confidence: 99%

Section: Introductionmentioning

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.

View full text Add to dashboard Cite

show abstract

“…Currently, in all Kibble balance experiments, a permanent magnetic circuit is adopted as the most practical solution when balancing the mechanical power with the electrical one. Originally designed by the International Bureau of Weights and Measures (BIPM) [38], a typical symmetrical permanent magnetic circuit is widely used by worldwide Kibble balance experiments. Generally, SmCo is used as the permanent magnetic material since it has high performance and a low temperature coefficient.…”

Section: Asymmetry In Moving Magnet Kibble Balancesmentioning

confidence: 99%

External Magnetic Field Measurements in UME Kibble Balance

Ahmedov¹,

Korutlu²,

Dorosinskiy³

et al. 2020

ACTA IMEKO

View full text Add to dashboard Cite

The new definition of kilogram in terms of the fixed value of Planck constant ensures the long-term stability of SI mass unit and enables traceability from more than one source. Kibble balance experiments offer an effective primary realization method for the new definition of kilogram. Kibble Balance apparatus operating at National Metrology Institute of Turkey is designed with a stationary coil and an oscillating magnet. In contradistinction to traditional moving coil Kibble balance experiments, external magnetic field brings an asymmetry between the Ampere’s law of force and the Faraday’s law of induction in moving magnet experiments. In this paper, we develop a method based on the external magnetic flux density difference measurements in vertical direction to take into account the effect of the external magnetic field on the realization of kilogram. The proposed model in this approach fits well with the data such that the kilogram realization requirement is met within the accuracy of the measuring instrument.

show abstract

“…In the revised SI, the kilogram can be realized by linking a mass to the Planck constant, for example, through either the Kibble balance experiment or the x-ray crystal density method. Many national metrology institutes are conducting experiments to realize and disseminate the kilogram in terms of h [1][2][3][4][5][6][7][8][9][10][11]. The Korea Research Institute of Standards and Science (KRISS) is developing a Kibble balance to realize the kilogram in Korea and to contribute to the worldwide mass scale.…”

Section: Introductionmentioning

confidence: 99%

Realization of the kilogram using the KRISS Kibble balance

Kim

Seo

et al. 2020

Metrologia

View full text Add to dashboard Cite

In the revised international system of units (SI), the kilogram is realized through methods linking mass to the Planck constant such as the Kibble balance experiment and x-ray crystal density method. We report on the first experiment for kilogram realization at the Korea Research Institute of Standards and Science (KRISS). The masses of two artefacts (platinum–iridium and stainless steel) were measured using the KRISS Kibble balance between December 2019 and January 2020 at a pressure between 3 × 10–3 Pa and 4 × 10–3 Pa. The relative standard uncertainty of the realization experiment was 1.2 × 10–7. The mass of the platinum–iridium artefact (No. 111) determined by the KRISS Kibble balance experiment was 2 µg different from the mass determined by historical traceability to the international prototype of the kilogram (IPK) in the previous SI. For the stainless steel artefact, the difference in mass value determined by the KRISS Kibble balance and historical traceability was 56 µg.

show abstract

The BIPM Kibble Balance for the Realization of the Redefined Kilogram

Cited by 8 publications

References 8 publications

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

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

External Magnetic Field Measurements in UME Kibble Balance

Realization of the kilogram using the KRISS Kibble balance

Contact Info

Product

Resources

About