High-performance bench-top cylindrical magnetic shield with magnetic shaking enhancement

A high-performance bench-top cylindrical magnetic shield made of amorphous ribbons is presented. It has double active shells made of Metglas 2705M amorphous ribbon to which magnetic shaking enhancement is applied. Passive shells made of Metglas 2714A amorphous ribbons were installed to reduce the leakage field of magnetic shaking. With total weight 1.3 kg of the amorphous ribbons, sufficiently large shielding performance was measured against 10-/spl mu/T, 10-Hz uniform magnetic field. The value of the axial shielding factor (ASF) was 700 and transverse shielding factor (TSF) was more than 20,000. The residual dc fields were less than 20 nT in the axial direction and 5 nT in the radial direction under the worst condition, where the shield axis is oriented along the horizontal component (/spl sim/ 32 /spl mu/T) of the Earth's magnetic field.