Magnetic shielding by superconducting windings for shielding axial external magnetic field with spatial distribution of a function of axial co-ordinates

Abstract

This paper describes an analytical study on magnetic shielding by a set of superconducting windings for applications such as low magnetic field measurement using SQUIDs (superconducting quantum interference device) and magnetic resonance imaging. Fundamental equations to be satisfied by the coil system are studied and a direct method to determine coil parameters are proposed. The proposed method was applied to obtain coil configurations for shielding axial external magnetic field with spatial distribution of uniform or linear gradient along axis. Comparison of the shielding factor proves that superconducting windings can achieve better shielding factors than superconducting cylinder with same aspect ratio.