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 realize a Kibble balance magnet with zero coil-current effect and good shielding at the same time. A permanent magnet system with two gaps each housing a coil is employed in the proposed design to minimize the coil current effect. Both air gaps of the magnet are completely surrounded by high-permeability material, and hence the coils are shielded from outside magnetic fields and consequently, no magnetic field leaks outside 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.
, Li, S.
and Stock, M.
A new magnet design for future Kibble balances, Metrologia, [online], https://dx.doi.org/10.1002/DOI: 10.1088/1681-7575/aab2ea, DOI: 10.1088/1681-7575/aab2ea
(Accessed March 1, 2024)