| 摘要 |
PURPOSE: To reduce the leakage in the axial direction of a tubular shield enough to reduce the total leakage magnetic field by forming superconductor flanges in the inside direction of the opening ends of a tubular shield so that the angle of the generating line of each flange is within a specific deg. to the center axis of the shield. CONSTITUTION: Superconductor flanges 21, 22 are formed in the inside direction of the opening ends of a tubular shield so that the angle of the generating line of each flange 21, 22 is 15-75deg. to the center axis of the shield 11. If the angle 6 is made, a magnetic field 4 caused by an image current flowing in the superconductor and that 4' caused by a current flowing in a magnet can be kept away to result in the reduction of a concentrated magnetic field composed of the sum of the magnetic fields caused by both currents on the surface of the superconductor. If the angle 6 is 75-90deg., the effect to shift the image current flowing in the superconductor cannot be obtained and if 0-15deg., there is little effect of the flanges and the concentrated field leakage reduction effect cannot be obtained. For this reason, the tangent of the flanges is at 15-75deg. to the center axis of the magnet. |
