| 摘要 |
1,239,204. Superconductor magnets; discharge apparatus. BRITISH OXYGEN CO. Ltd. 3 Oct., 1968 [4 Oct., 1967], No. 45277/67. Headings H1D and H1P. An electromagnet comprises a tubular support having at least one longitudinally extending former on the external surface, the former having enlarged end portions the radii of curvature of which are nowhere less than the minimum radius of curvature to which a superconductor strip may be wound, the superconductor strip being wound on to the former with the adjacent turns separated by thin spacers at the end portions of the former and by thick spacers at the intermediate portions of the former. As shown, Fig. 4, the tubular support is provided with a former 6 having bulbous ends 20. Layers 8 of superconductor are wound round the former with thick spacers 12 over the straight portions and thin spacers 22 over the curved portions. The superconductor may be a ribbon of stainless steel coated with Nb 3 Sn and the spacers may be of non-magnetic stainless steel. A quadrupole magnet for focusing a beam of charged particles may be produced by providing the tubular support with four such coils spaced around its circumference. The thickness of the spacers over the straight portions of the former may be varied so that the outer turns of the coil are closer together than the inner turns. If in winding the coil a point is reached at which the straight portion of the turn is tangential to the curved end part any subsequent turns are wound with spacers of constant thickness over the straight and curved parts of the former. The spacers may have radially tapered cross-sections. The magnet may also be employed for separating the magnetic and non-magnetic fractions of ores and minerals. |
