MAGNETIC FIELD SHIELDING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a light and small magnetic field shielding device with high performance. SOLUTION: A plurality of sheets with high magnetic permeability are arranged by partial superimposition on a plurality of non-magnetic cylindrical members which are disposed by concentrically enclosing a first direction axis to have a hollow part. The most internal cylindrical member is provided with first and second openings 41 and 42 at one end and the other end in the first direction and with a third opening 43 which puts through the plurality of cylindrical members in a vertical direction with respect to the first direction axis and where a cryostat for keeping low temperature in pluralities of SQUID flux meters is inserted. A component in the vertical direction concerning the first direction in an extraneous magnetic field is shielded in the internal space of the most inner cylindrical member. Each cylindrical member is divided into first and second parts 40-1 and 40-2 in the first direction, the first part is movable in the first direction, the respective first and second cylindrical member are provided with first and second semi-circular notches opening in each end part and the third opening is formed by the movement of the first part and by the first and second notches.