| 摘要 |
A superconducting magnet assembly comprises superconducting main magnet coils 10 electrically connected in series between a first current connection 21 and a second current connection 21a, superconducting shim coils 42, superconducting switches 36, 44 and solid state switches 60, 64. To energize main coils 10, MOSFET switch 60 is opened and MOSFET switches 64 are closed. To energize shim coils 42, switch 60 is closed and switch 64 of the selected shim coil is opened. Alternatively, MOSFETs 64 may be used as current controls rather than on/off switches and all shim coils may be energized simultaneously. In an alternative embodiment (figure 6, not shown) all shim coils 42 are connected to a single solid state switch and are energized selectively by operating parallel superconducting switches 42. The apparatus allows main coils 10 and shim coils 42 to be energized by the same external lead 34 crossing the OVC. |
