A new magnet design for future Kibble balances

Li, Shisong; Stöck, M; Schlamminger, Stephan

doi:10.1088/1681-7575/aab2ea

“…The rare-earth permanent magnet as a magnetic field source is mainly employed in watt balance experiments [8,13]. The permanent magnet produces a magnetic field that affects the measuring coil causing a voltage drop when the coil travels vertically during the moving stage and a force when the coil is activated by current during the weighing stage.…”

Section: Permanent Magnet Systemmentioning

confidence: 99%

Single-channel EEG processing for sleep apnea detection and differentiation

Prucnal,

Polak

2023

Metrology and Measurement Systems

1

0

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The Kibble balance experiment is used to redefine the kilogram as a unit of mass based on the Planck constant. To demonstrate and understand the basic principle of the Kibble balance, the National Institute of Standards (NIS)-Egypt has constructed a prototype Kibble balance that can measure gram-level masses with 0.01% relative uncertainty. Through the construction of this prototype, the challenges can be studied and addressed to overcome the weaknesses of NIS's prototype. This study presents the design and construction of the prototype Kibble balance. It also focuses on the design and performance of the magnetic system, which is a crucial element of the Kibble balance. Analytical modeling and finite element analysis were used to evaluate and improve the magnet system. Several other aspects were also discussed, including the yoke's material and enhancing the magnetic profile within the air gap of the magnet system. Over a vertical distance of 30 mm inside the air gap, the magnetic flux density was found to be 0.3 T, and the uniformity was found to be 8 × 10 −5 .

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“…In addition, the entire system is covered with aluminum sheets for electromagnetic shielding and temperature homogeneity. In the UME-KB3 experiment, NPL type magnet assembly is used with two air gaps for the coil pair [21,22]. The sliced view of the rotationally symmetric UME magnet assembly is given in figure 3.…”

Section: Description Of Ume Kb-3mentioning

confidence: 99%

UME Kibble balance operating in air

Ahmedov¹,

Orhan²,

Korutlu³

2022

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The UME KB-3 operating since 2020 allows the realization of kilogram under ambient air conditions owing to its distinguishing design and operation protocol. This is possible only because the coil pair is stationary but the surrounding magnet assembly is moving. The mechanically decoupled nature of the magnet assembly allows the implementation of a local vacuum for displacement measurements rather than a vacuum covering the entire apparatus. The balance operates in single mode with simultaneous operation of weighing and moving phases instead of successive phases. A novel dynamical measurement procedure is developed in order to conform with the single phase measurements. The paper describes the apparatus and presents the measurement results for stainless steel mass artefact with a nominal value of 1 kg. The mass of the artefact is measured with a total relative uncertainty of 54 ppb.

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“…The rare-earth permanent magnet as a magnetic field source is mainly employed in watt balance experiments [8,13]. The permanent magnet produces a magnetic field that affects the measuring coil causing a voltage drop when the coil travels vertically during the moving stage and a force when the coil is activated by current during the weighing stage.…”

Section: Permanent Magnet Systemmentioning

confidence: 99%

Establishing and characterizing a permanent magnet system for the prototype of NIS's Kibble balance

Emira,

Shaaban,

Rashad

et al. 2022

Metrology and Measurement Systems

0

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The Kibble balance experiment is used to redefine the kilogram as a unit of mass based on the Planck constant. To demonstrate and understand the basic principle of the Kibble balance, the National Institute of Standards (NIS)-Egypt has constructed a prototype Kibble balance that can measure gram-level masses with 0.01% relative uncertainty. Through the construction of this prototype, the challenges can be studied and addressed to overcome the weaknesses of NIS's prototype. This study presents the design and construction of the prototype Kibble balance. It also focuses on the design and performance of the magnetic system, which is a crucial element of the Kibble balance. Analytical modeling and finite element analysis were used to evaluate and improve the magnet system. Several other aspects were also discussed, including the yoke's material and enhancing the magnetic profile within the air gap of the magnet system. Over a vertical distance of 30 mm inside the air gap, the magnetic flux density was found to be 0.3 T, and the uniformity was found to be 8 × 10 −5 .

show abstract

A new magnet design for future Kibble balances

Cited by 7 publications

References 29 publications

Single-channel EEG processing for sleep apnea detection and differentiation

Single-channel EEG processing for sleep apnea detection and differentiation

UME Kibble balance operating in air

Establishing and characterizing a permanent magnet system for the prototype of NIS's Kibble balance

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