A human-size magnetic shield of cylindrical structure (inner diameter: 92 cm, length: 220 cm) has been constructed with magnetic shaking enhancement. The weights of the magnetic materials used are 69 kg for Metglas 2705M amorphous tapes and 40 kg for Permalloy tapes and the total weight was about 250 kg. The shielding factor at the center was 4000 for a transverse magnetic field of 10 μT, 1 Hz and residual dc magnetic field was as small as 1 - 2 nT when compensation for open ends was applied. The noise level of the shield measured, when open end compensation was off, by a SQUID magnetometer at the center of the shield was 54 fT/√Hz at 1 Hz and 23 fT/√Hz at 10 Hz.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Electrical and Electronic Engineering