| 摘要 |
A superconducting magnet arrangement 100, a method of protecting a superconducting magnet or a magnetic resonance imaging system, comprises: superconducting coils 106, 108, 110, 112 within a cryogenic vessel 102, which are connected to a power supply 114. A dump resistor 127 is located external to the vessel 102. The magnet is provided with a switch 126 and a control device 128 with means to dump the energy of the magnet through the dump resistor 127. The switch 126 may be opened to provide the magnet with a ramp mode of operation or closed to provide the magnet with a persistent current mode of operation. The coils 106, 108, 110, 112 are connected in series and may be linked at tap points to heater elements which may be arranged to open the switch 126 when a quench condition arises in the coils. Various forms of quench detection may be used with the control device 128 of the magnet arrangement. A relay switch 120 may be used to switch between a power supply 114 or a dump resistor 127 being connected across the magnet leads 116, 118.
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