Open AccessA new magnet design for future Kibble balances
Author(s) -
Shisong Li,
M Stöck,
Stephan Schlamminger
Publication year - 2018
Publication title -
metrologia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.637
H-Index - 79
eISSN - 1681-7575
pISSN - 0026-1394
DOI - 10.1088/1681-7575/aab2ea
Subject(s) - magnet , electromagnetic coil , electromagnetic shielding , air gap (plumbing) , shielded cable , magnetic field , electromagnet , mechanical engineering , electrical engineering , physics , nuclear engineering , nuclear magnetic resonance , computer science , materials science , engineering , quantum mechanics , composite material
We propose a new permanent magnet system for Kibble balance experiments, which combines advantages of the magnet designs invented by the National Physical Laboratory (NPL) and by the Bureau International des Poids et Mesures (BIPM). The goal of the proposed magnet system is to minimize the coil-current effect and to optimize the shielding at the same time. In the proposed design, a permanent magnet system with two gaps, each housing a coil, is employed to minimize the coil current effect, by reducing the linear coil-current dependence reported for the single air gap design by at least one order of magnitude. Both air gaps of the magnet are completely surrounded by high-permeability material, and hence the coils are shielded from outside magnetic fields and no magnetic field leaks outside of the magnet system. An example of the new magnet system is given and the analysis shows that the magnetic field in the air gap can be optimized to meet the requirement to be used in Kibble balances.