PURPOSE: To perfectly eliminate uneven magnetic field to be compensated by setting the same time constant to the main coil and compensating coil group during operation on the occasion of configurating a magnet with the main coil which generates the main magntic field, compensating coil group for enhancing space uniformity of magnetic field generated and a permanent current switch for permanently operating with a current.
CONSTITUTION: A closed circuit 2d comprising a pemanent current swich 2a which generates heat by a heater 2b is connected to the main coil 2 and a leadout wires 2c are provided at both ends of switch 2a. The compensating coil group 3 is wound around the outer circumference of the main coil 2, a permanent current switch 3a which heats with a heater 3b is connected to both ends of such coil groups. Simultaneously, a closed circuit 3d is formed in the same way and the leadout wires 3c are extended from both ends of the switch 3a. In such a structure, the equivalent circuits of the closed circuits 2d and 3d respectively comprise resistances RM and RC, and inductances LM and LC. However, at this time, the time constants of them are specified to the same value so that the relation LM=RM=LC/RC can be obtained.
MORITA MASAO
YAMADA TADATOSHI
