| 摘要 |
PURPOSE:To obtain the most inexpensive superconductive magnet by conjointly using a self-shield and an active shield to allow a ratio of either absorbing or offsetting a principal coil-generated leakage magnetic field to be varied to thereby change the weight of the superconductive magnet. CONSTITUTION:A principal coil 3 consisting of an axially symmetrical superconductive coil; an active shield 2 consisting of a superconductive coil coaxially arranged on the outer side of the coil 3; a cylindrical, magnetic self- shield 1 coaxially arranged on the outer side of the shield 2 are provided. The magnetic moment of the shield 2 is smaller than that of the coil 3 in terms of absolute value and is opposed in terms of direction. By setting the magnetic moment of the shield 2 to a proper value, the dimensions and weight of the shield 1 can be freely set. Accordingly, the most inexpensive superconductive magnet can be obtained. |
