Superconducting magnet coil with reduced current density regions

摘要

A superconducting magnet comprises a cylindrical bobbin with a cylindrical member 1 and end flanges 2, 3 and at least one section of multi-layer continuously wound superconductive strip 6, 7, 9. Coil regions 5, 8, 11 are separated by hollow cylindrical regions 4a, 4b, 4c of material of different axial length and / or radial thickness. The cylindrical regions 4a, 4b, 4c sequentially extend from alternate end flanges 2, 3 of the bobbin when moving in a radial direction. Adjacent hollow cylindrical regions have overlapping portions which are separated by at least one layer of the continuous winding 7. The hollow cylindrical regions 4a, 4b, 4c may comprise filler material, high temperature superconductive blind strip windings or solid material shells. The inner most cylinder 4a may be formed as one piece with the bobbin. The magnet may use stacked strip windings connected in parallel and superconductive means may be arranged to short-circuit the magnet coil. The coil and reduced current density region arrangement may be suitable for high temperature superconducting (HTS) strip conductor by minimising the mechanical load placed on the conductor. The magnet arrangement may provide a notch region (reduced current region) which may be used to correct magnetic field inhomogenities and may be used in a high field NMR system.