Apparatus and method for protecting a magnetic resonance imaging magnet during quench

A method of protecting a superconducting magnet assembly during a quench condition, the method comprising:

• coupling a controller to at least one superconducting magnet coil portion disposed within a vessel;
• connecting the at least one superconducting magnet coil portion to a power supply during a magnet ramp mode of operation and connecting the at least one superconducting magnet coil portion to a dump resistor during a persistent mode of operation, such that the at least one superconducting magnet coil portion is electrically disconnected from the power supply during the persistent mode of operation, but with current continuing to circulate through the at least one superconducting magnet coil portion during the persistent mode of operation such that the at least one superconducting magnet coil portion continues to operate;
• monitoring signal from at least one superconducting magnet coil portion to detect the onset of a quench condition;
• detecting the quench condition based on the monitored signal;
• and
• sending a signal from the controller to a ramp switch coupled to the at least one superconducting magnet coil portion to open the ramp switch if a quench condition is detected by the controller in order to discontinue a persistent mode of operation and in order to connect the at least one superconducting magnet coil portion to the dump resistor.

A magnetic resonance imaging system comprising:

• a superconducting magnet coil assembly disposed within a vessel;
• a power supply disposed externally to the vessel, wherein the power supply is removably coupleable to the superconducting magnet coil assembly via permanently embedded leads in the vessel;
• a ramp switch disposed within the vessel and coupled to the superconducting magnet coil assembly, wherein the ramp switch is configured to be open during a magnet ramp mode of operation and closed during persistent mode of operation;
• an external dump resistor disposed externally to the vessel, wherein the external dump resistor is coupled to the superconducting magnet coil assembly via cables coupled to the permanently embedded leads in the vessel;
• and
• a quench protection controller disposed externally to the vessel and coupled to the superconducting magnet coil assembly and the ramp switch, wherein the quench protection controller is configured to detect a quench condition based upon measured signals of the superconducting magnet coil assembly and to open the ramp switch in order to dump magnet energy to the external dump resistor when a quench condition is detected.