Open Magnetic Shielding by Superconducting Technology

Until recently, a new type of open magnetic shielding system was realized by the combination of a series of closed high temperature superconductor coils. We experimentally confirmed that the shielding factor (SF) of the new shielding system can reach more than 40 dB in the frequency spectrum of 0.1-16 000 Hz. Because of its superior ability to resist alternating magnetic field, we named, the system Tesla-shielding (TS), to commemorate the father of alternating current, Nikola Tesla. In this paper, we will report the design and realization of a Helmholtz coil-based TS. The Helmholtz TS has many advantages over the previous planar TS. Especially, the Helmholtz TS has an engineering way of regulating the device for a better SF. We will introduce the design of the Helmholtz TS with the help of numerical simulation. The main electromagnetic properties of the TS, such as SF in the frequency spectrum and its shielding ability in the long duration measurement, are given in this paper.