| 摘要 |
PROBLEM TO BE SOLVED: To realize reduction in size of the superconducting magnet device including a magnetic shield for preventing leakage of the magnetic field to unwanted portion, while canceling force of the superconducting coil attracting a magnetic shield. SOLUTION: The superconducting magnet device internally comprises superconducting coils 15A to 15D and a vacuum vessel 13. The device is also provided with an upper plate 12A and a lower plate 12B for holding the superconducting coils 15A to 15D, and a magnetic shield 12 for preventing leakage magnetic field from the coils. The device can be reduced in size by making smaller the distance h3 between the magnetic shield 12A and the vacuum vessel 13 than the distance h2 between the lower plate 12B and vacuum vessel 13. Moreover, a magnetic resistance for the lower plate 12B is made larger by reducing thickness of the upper plate 12A, and accordingly the force F1 of the superconducting coils 15A to 15D for attracting the upper plate 12A becomes equal to the force F2 for attracting the lower plate 12B. COPYRIGHT: (C)2007,JPO&INPIT |
