Patent ID: 7330341

Claim:
A superconducting magnet coil system comprising: a main field coil formed from radially nested sections which are connected in series and which comprise conductors, said conductors of radially inner sections of said main coil comprising a first superconducting material and having a first electric voltage insulation, conductors of radially outer sections of said main coil comprising a second superconducting material having a second electric voltage insulation, wherein said first superconducting material has a higher critical magnetic field than said second superconducting material, said first voltage insulation having at least areas of smaller dielectric strength than said second voltage insulation; a shielding coil connected in series with and radially surrounding said main field coil, said shielding coil having conductors which contain said second superconducting material and which are surrounded by said second electric voltage insulation, wherein said main field coil and said shielding coil are superconductingly short-circuited during operation; at least one ohmic resistance and/or diode connected in parallel with said radially inner sections of said main field coil for quench protection thereof; and one single further ohmic resistance and/or one single diode circuited for quench protection of said radially outer sections of said main field coil and of said shielding coil.