| 摘要 |
PURPOSE:To make the degaussing speeds of two closed circuits respectively containing the first coil group and permanent current switch and the second coil group and another permanent current switch almost equal to each other so as to prevent the spreading of a leakage magnetic field by respectively providing resistance generating elements which make the current attenuating speeds of the closed circuits equal to each other to the circuits. CONSTITUTION:A closed circuit containing the first superconducting coil group 1 for generating a necessary magnetic field in an objective space, permanent current switch 3, and resistance generating element 11 and another closed circuit containing the second coil group 2 for generating a magnetic field which is produced nearly concentrically and coaxially to that of the first coil group for reducing the occurrence of a leakage magnetic field, permanent current switch 6, and resistance generating element 14 are housed in a cryostatic container 19. Those which can make the current attenuating speeds of the circuits are used as the elements 11 and 14. At the time of making emergency demagnetization, the heaters 13 and 16 of the elements 11 and 14 are energized so that super-conductive substances 12 and 15 can be shifted to normal conductive states and resistances can be produced. Therefore, the energy stored in the circuits is consumed and the magnetic fields generated by the coil groups 1 and 2 are demagnetized. |
