Technique for high axial shielding factor performance of large-scale, thin, open-ended, cylindrical Metglas magnetic shields

摘要

Metglas 2705M is a low-cost commercially-available, high-permeabilityCobalt-based magnetic alloy, provided as a 5.08-cm wide and 20.3-$\mu$m thickribbon foil. We present an optimized construction technique for single-shell,large-scale (human-size), thin, open-ended cylindrical Metglas magneticshields. The measured DC axial and transverse magnetic shielding factors of our0.61-m diameter and 1.83-m long shields in the Earth's magnetic field were 267and 1500, for material thicknesses of only 122 $\mu$m (i.e., 6 foil layers).The axial shielding performance of our single-shell Metglas magnetic shields,obtained without the use of magnetic shaking techniques, is comparable to theperformance of significantly thicker, multiple-shell, open-ended Metglasmagnetic shields in comparable-magnitude, low-frequency applied external fieldsreported previously in the literature.