| 摘要 |
PURPOSE:To realize a magnetic field far lower than an outside magnetic field by arranging high-permeability cylindrical members, which have openings along the longitudinal direction of a cylindrical shield substance, inside that cylindrical shield substance, leaving space with the cylindrical inwall. CONSTITUTION:One high-permeability material FM each is arranged in the positions 800mm from the center of a superconductive cylinder SC, both whose ends are opened. The sizes of the superconductive cylinder SC are 100mm in inside diameter, 240mm in length, and 5mm in thickness. The high-permeability material cylinder FM is 10mm in length and 10000 in permeability, and the outside diameter Dmm is changed. As a result of measurement, it comes out that if the high-permeability material cylinder FM, which has an outside diameter 1/5 or more times as large as the superconductive cylinder SC, is arranged inside the superconductive cylinder SC, the shield effect more excellent than the superconductor cylinder simple can be gotten, and also the more the outside diameter of the high-permeability material cylinder FM approximates to the inside diameter of the superconductive cylinder SC, the more excellent shield effect can be obtained. |
