| 摘要 |
PROBLEM TO BE SOLVED: To provide a magnetic field measuring instrument with high performance through the use of sheets with high magnetic permeability. SOLUTION: The instrument is provided with a magnetic field shielding device 40 where a plurality of sheets having high magnetic permeability are arranged by partial superimposition on a plurality of non-magnetic cylindrical members which is arranged by concentrically enclosing a first direction axis to have a hollow part, where the most inner 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 being put through the cylindrical members in a vertical direction with respect to the first direction axis and also by which 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. The instrument is also provided with loading devices 20, 21 and 22 arranged in the inner space to hold a living body by permitting a body axial direction to be in nearly parallel to the first direction axis and a cryostat 50 which is inserted to the third opening, whose bottom surface is disposed in the inner space and by which low temperature is kept in pluralities of SQUID flux meters. The SQUID flux meters 50 detects the component in the vertical direction concerning the first direction of the magnetic field generated from the living body. Thus, the light and small magnetic field measuring instrument is provided at a low cost. |
