| 摘要 |
An actively shielded, superconducting magnet arrangement for the generation of a magnetic field in the direction of a z axis in a working volume arranged about z=0, having a radially inner and a radially outer coaxial coil system, wherein the two coil systems carry the same current and have dipole moments of the same magnitude, but of opposite directions, wherein parts of the radially outer coil system (C2') are electrically connected in series with the radially inner coil system (C1) and wherein a first superconducting switch (S1) is provided via which during operation a superconducting short circuit of a first current path of the magnet arrangement can be effected, is characterized in that a section (A') of the radially outer coil system (C2'), which can be superconductingly short-circuited during operation via a further superconducting switch (S2) is arranged symmetrically to the plane z=0 and that the further superconducting current path formed by the superconductingly short-circuited section is inductively decoupled from the other parts of the magnet arrangement connected in series. In this way, undesired side effects like an increase of the magnet drift or uncontrolled charging of the section (distortion with time of homogeneity, possible increase of the stray field, charging up to quenching) are avoided with simple means without the necessity of a current limiter.
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