Multi-layer magnetic shield

PROBLEM TO BE SOLVED: To reduce the weight of a magnetic shield (a passive shield) formed by a magnetic material disposed at an outer side of a superconducting magnet.SOLUTION: A magnetic shield made of a magnetic material disposed at an outer side of a superconducting magnet 11 is a multilayer magnetic shield 21 including at least a cylindrical first magnetic shield 1 disposed at the outer side of the superconducting magnet 11 and a cylindrical second magnetic shield 2 which is disposed on an outer side of the first magnetic shield 1 so as to be spaced a predetermined distance S away from the first magnetic shield 1. Each of the first magnetic shield 1 and the second magnetic shield 2 has: cylindrical parts 1a, 2a disposed at a radial outer side of the superconducting magnet 11; and a pair of flange parts 1b, 2b disposed at an axial outer side of the superconducting magnet 11 and extending inward from both axial end parts of the cylindrical parts 1a, 2a.SELECTED DRAWING: Figure 1