| 摘要 |
PURPOSE:To demagnetize a superconducting magnet in a short time when it is operated in a permanent current mode by providing an emergency demagnetizing unit having a heater circuit and a heater circuit opening/closing switch connected in series with the circuit. CONSTITUTION:A superconducting coil heater 7 is heated by energizing it by a heater power source 8 by closing a heater circuit opening/closing switch 9 to heat a superconducting coil 1. When it exceeds a predetermined critical temperature due to the temperature rise, at least part of the coil 1 is transferred to a normal conducting state to generate a resistance. Even if the small part of the coil 1 is transferred to the normal conducting state, Joule loss occurs due to the resistance of this part to increase the normal conducting transferring part. Thus, an exciting current Ic circulated in a closed circuit having the coil 1 and a permanent current switch superconductor 3 is abruptly attenuated to demagnetize the coil 1. |
