Magnetic shielding is crucial for the reliable operation of electronic and electromechanical components in environments with strong magnetic fields. In this work, the shielding performance of ferromagnetic materials is experimentally investigated for static magnetic fields in the range of 20 to 150 mT . Motivated by the extension of the laser blow-off system at the Wendelstein 7-X stellarator, systematic measurements are carried out to examine the influence of material type, thickness, and orientation relative to the external magnetic field. Cuboid-shaped enclosures made of pure iron and high-permeability metal with thicknesses between 3 and 6 mm are studied. Mu-metal provides superior shielding at low field strengths below approximately 70 mT , while pure iron exhibits better performance at higher fields. Increasing material thickness and employing multiple layers enhance shielding effectiveness across the entire field range. Under optimized conditions, a reduction of the external magnetic field by up to 75% is achieved.
Wegner et al. (Mon,) studied this question.