Patent ID: 6700469
Filing Date: 2004-03-02
Classification: G01R

Abstract:
A magnet system for generating a magnetic field (H) in the direction of a z axis in a working volume (AV) disposed on the z axis about z=0, the system comprising:a radially inner partial coil system (C1); a radially outer partial coil system (C2) disposed coaxially with respect to said radially inner coil system, said radially inner and outer coil systems having magnetic dipole moments in an operating state of opposite signs and differing by an amount &Dgr;m, with |&Dgr;m|<2.5% of a magnitude of a magnetic dipole moment of said radially inner partial coil system (C1), said radially inner and outer coil systems being parts of an actively shielded superconducting magnet coil system (M); and at least one current path (P1, . . . , Pn) which is superconductingly closed in the operating state, wherein said at least one current paths (P1, . . . , Pn) are, at least at certain times, superconductingly short-circuited during charging of said actively shielded superconducting magnet coil system (M), wherein said current paths (P1, . . . , Pn) are designed such that currents induced therein due to charging of said magnet coil system (M) generate an overall magnetic dipole moment of a magnitude of at least 0.1% of a magnitude of a magnetic dipole moment of a charged said radially outer partial coil system (C2) to optimize fringe field behavior outside of the magnet system.