First realisation of the kilogram with the METAS Kibble balance

Eichenberger, A.; Baumann, Henri; Mortara, A.; Tommasini, D.; Reber, D.; Klingelé, E.; Jeanneret, B.; Jeckelmann, B.

doi:10.1088/1681-7575/ac566f

Cited by 7 publications

(5 citation statements)

References 19 publications

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“…This delivers the amplitudes U 0 and v 0 . 5 Then, these amplitudes are taken to calculate the force factor as…”

Section: Fundamental Equationsmentioning

confidence: 99%

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A method for evaluating the force factor in oscillating Kibble balances with application to the Planck-Balance

Rothleitner,

Poroskun,

Svitlov

et al. 2023

Metrologia

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The Planck-Balance is a table-top version of a Kibble balance, developed in a collaboration between the PTB and TU Ilmenau. In contrast to most Kibble balances, where the motion range is of up to several centimetres in the velocity mode, in the Planck-Balance it is below 100 μm. For a reliable determination of the force factor, the voice coil is set into harmonic oscillation, resulting in an induced AC voltage. The amplitude of the first harmonic is then taken to determine the force factor. However, due to the non-linear magnetic field across the motion range, the first harmonic is subject to a bias, and higher harmonics are excited. Those higher harmonics contain the information about the relative magntitude of the bias in the first harmonic, and can be used for a correction. In this paper we present an analytical model and show its application with real measurements. The estimated relative bias amounts to −6.3·10−6, with a residual relative uncertainty of 6.3 · 10−7, for an oscillation amplitude of 20 μm. This method is especially of importance for Kibble balances with short motion range and working with harmonic oscillation. After such a correction is applied, a table-top version of a Kibble balance can be used as a conventional balance calibrated by means of E2 mass standards in the whole E2 class mass range.

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“…This delivers the amplitudes U 0 and v 0 . 5 Then, these amplitudes are taken to calculate the force factor as…”

Section: Fundamental Equationsmentioning

confidence: 99%

“…Here, the coil of the voice coil actuator is moved with a (usually) linear trajectory through the magnetic field of a permanent magnet (see, e.g. [5][6][7][8][9][10]). The induced DC voltage is measured synchronously to the position of the coil (from which its velocity is derived).…”

Section: Introductionmentioning

confidence: 99%

A method for evaluating the force factor in oscillating Kibble balances with application to the Planck-Balance

Rothleitner,

Poroskun,

Svitlov

et al. 2023

Metrologia

View full text Add to dashboard Cite

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“…Detailed descriptions of the Kibble-balance experiments can be found in Refs. [29][30][31][32][45][46][47][48][49][50][51].…”

Section: The Kibble Balance Methodsmentioning

confidence: 99%

Avogadro and Planck Constants, Two Pillars of the International System of Units

Massa

2024

Physics

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The International System of Units (SI), the current form of the metric system and the world’s most used system of units, has been continuously updated and refined since the Metre Convention of 1875 to ensure that it remains up to date with the latest scientific and technological advances. The General Conference on Weights and Measures, at its 26th meeting in 2018, decided to adopt stipulated values of seven physical constants linked to seven measurement units (the second, meter, kilogram, ampere, kelvin, mole, and candela). This paper reviews the technologies developed, in intense and long-standing work, to determine the Avogadro and Planck constants, which are now integral to realising the kilogram.

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“…Although flexure-based weighing cells have been used in Kibble balances, most of these designs ignore KRT, because a different mechanism is used to move the coil than to perform the precise weighing. Examples include the Kibble balances built in Switzerland, Korea, and at the BIPM, [11][12][13]. Not taking advantage of KRT may come at a performance cost-a balance that outperforms the original NPL balance designed by Kibble and Robinson still needs to be built.…”

Section: Introductionmentioning

confidence: 99%

Flexures for Kibble balances: minimizing the effects of anelastic relaxation

Keck,

Schlamminger,

Theska

et al. 2024

Metrologia

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We studied the anelastic aftereffect of a flexure being used in a Kibble balance, where the flexure is subjected to a large excursion in velocity mode after which a high-precision force comparison is performed. We investigated the effect of a constant and a sinusoidal excursion on the force comparison. We explored theoretically and experimentally a simple erasing procedure, i.e. bending the flexure in the opposite direction for a given amplitude and time. We found that the erasing procedure reduced the time-dependent force by about 30%. The investigation was performed with an analytical model and verified experimentally with our new Kibble balance at the National Institute of Standards and Technology employing flexures made from precipitation-hardened Copper Beryllium alloy C17200. Our experimental determination of the modulus defect of the flexure yields 1.2 × 10 − 4 . This result is about a factor of two higher than previously reported from experiments. We additionally found a static shift of the flexure’s internal equilibrium after a change in the stress and strain state. These static shifts, although measurable, are small and deemed uncritical for our Kibble balance application at present. During this investigation, we discovered magic flexures that promise to have very little anelastic relaxation. In these magic flexures, the mechanism causing anelastic relaxation is compensated for by properly shaping and loading a flexure with a non-constant cross-section in the region of bending.

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First realisation of the kilogram with the METAS Kibble balance

Cited by 7 publications

References 19 publications

A method for evaluating the force factor in oscillating Kibble balances with application to the Planck-Balance

A method for evaluating the force factor in oscillating Kibble balances with application to the Planck-Balance

Avogadro and Planck Constants, Two Pillars of the International System of Units

Flexures for Kibble balances: minimizing the effects of anelastic relaxation

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