| 摘要 |
PURPOSE:To obtain an electromagnet adapted for the limited size of conveying and installing at a site while holding the uniformity of a magnetic field by altering the thicknesses of a yoke bridging over between a first quadrant and a fourth quadrant, between a second quadrant and a third quadrant, and a yoke bridging over the first quadrant and the second quadrant, between the third quadrant and the fourth quadrant on coordinates axis of the opening of the yoke. CONSTITUTION:A field coil 1 and a yoke 4 surrounding the coil 1 for forming a magnetic circuit are provided. The thicknesses of a yoke 4a bridging over between a first quadrant and a fourth quadrant, between a second quadrant and a third quadrant, and a yoke 4b bridging over between the first quadrant and the second quadrant, between the third quadrant and the fourth quadrant are different from each other on coordinates axis of the opening K of the yoke 4. For example, the yoke 4 surrounding a superconducting field coil 1 held at a low temperature by refrigerant in a low temperature vessel 2 is composed of the yokes 4a, 4b, the yoke 4a is reduced in thickness smaller than that of a predetermined magnetic circuit sectional size, and the yoke 4b is increased in thickness by the reduced amount. Thus, the lateral size W of an electromagnet is reduced without losing magnetic field uniformity and leakage magnetic field characteristic, and it can be conveyed to a narrow conveying inlet or installed in a narrow installing space. |
