Magnetic Field Leakage From a 45 -Angle Magnetic Shell and a Reduction Method for a High-Performance Magnetic Shield

A 45deg-angle shell is a key component of a cylindrical magnetic shield by which large shielding effects can be obtained for axially applied magnetic field and for the transversely applied magnetic field under magnetic shaking. A known problem with this shell is that a leakage magnetic field from edges of the shell is large. We have investigated a method to alleviate this problem through the use of passive magnetic layers, made of flexible magnetic sheets, which are padded inside the shell. We also utilized the layer in order to enhance the axial shielding factor (ASF). In this paper, we present our approach and the results of tests we carried out on several structures of thin passive layers with a small experimental model of a 45deg-angle shell. We were able to reduce the shaking leakage down to 1/14 and enhanced the ASF by six times