Although the so-called magnetic geometrical factor, Bl, of a Kibble balance does not appear in the Kibble equations, it offers the precision link between electrical and mechanical quantities and furthers a quasi-quantum traceability path for mass metrology. This feature makes the magnet system, supplying the Bl in Kibble equations, play a core role in Kibble balances. Following the open-hardware idea, we report here on the design, manufacture, assembly, optimization, and finally performance of a compact magnet system for the Tsinghua tabletop Kibble balance. Notably, the magnet system showcased in this study facilitates a straightforward upper levitation of splitting through a streamlined mechanism guide, substantially enhancing the ease of open and close operations. Experimental tests show the realized magnet systems can yield a high Bl value (e.g., 400 Tm for a bifilar coil and 800 Tm for a single coil with a wire gauge of 0.2 mm) meanwhile a low volume/weight (40 kg) thanks to the uniformity improvement of magnetic profiles. Furthermore, important parameters related to systematic effects, such as the current effect, are checked, aiming for a final mass-realization accuracy at the 10−8 level.
Cite
@article{arxiv.2409.03334,
title = {A Compact Magnet System for the Tsinghua Tabletop Kibble Balance},
author = {Yongchao Ma and Nanjia Li and Weibo Liu and Kang Ma and Wei Zhao and Songling Huang and Shisong Li},
journal= {arXiv preprint arXiv:2409.03334},
year = {2024}
}