Apparatus and method for the rapid discharge of superconducting magnet coil

A device for the safe discharge of a superconducting magnet coil with a cryostat for maintaining the coil at or below a cryogenic temperature, the magnet having a superconducting switch for superconductively short-circuiting the magnet during operation, the device comprising:

• an energy dissipation device located so as, during operation, to be at or below the cryogenic temperature;
• an optical or infrared transmitter located so as, during operation, to be above the cryogenic temperature;
• switching means for switching on the transmitter from outside the cryostat;
• and
• a receiver for the electromagnetic energy which comprises a heater resistor positioned adjacent the superconducting switch and a photoelectric cell electrically connected to the heater resistor to heat the superconducting switch, the receiver being electrically unconnected to the transmitter and being positioned in the vicinity of the superconducting switch at a location which, during operation, is at or below the cryogenic temperature, wherein the receiver comprises a surface which absorbs in the frequency range of the electromagnetic energy emitted by the transmitter and, upon reception of electromagnetic energy from the transmitter, the receiver effects a heating of the superconducting switch to cause it to lose its superconductivity, and thereby cause a discharge process of the superconducting magnet coil via the energy dissipation device.

A device for the safe discharge of a superconducting magnet coil within a cryostat for maintaining the coil at or below a cryogenic temperature, the magnet having a superconducting switch for superconductively short-circuiting the magnet during operation, the device comprising;

• an energy dissipation device located so as, during operation, to be at or below the cryogenic temperature;
• a transmitter of electromagnetic energy located so as, during operation, to be above the cryogenic temperature, the transmitter comprising at least one electric transmitter coil and an ac voltage generator generating an electrical signal at a resonant frequency;
• switching means for switching on the transmitter from outside the cryostat;
• a receiver which is electrically unconnected to the transmitter, and which is positioned in the vicinity of the superconducting switch at a location which, during operation, is at or below the cryogenic temperature, the receiver receiving the electromagnetic energy and comprising a coil of a resonant circuit which is resonant at said resonant frequency and inductively coupled with the transmitter coil, the receiver comprising at least one heater resistor which is adjacent the superconducting switch and connected to the resonant coil, and which forms part of said resonant circuit, the receiver further comprising a transformer stage to couple the energy from the receiver coil to the heater resistor such that, upon reception of electromagnetic energy from the transmitter, the receiver effects a heating of the superconducting switch to cause it to lose its superconductivity, and thereby cause a discharge process of the superconducting magnet coil via the energy dissipation device.

A device for the safe discharge of a superconducting magnet coil within a cryostat for maintaining the coil at or below a cryogenic temperature, the magnet having a superconducting switch for superconductively short-circuiting the magnet during operation, wherein the device comprises:

• an energy dissipation device located so as, during operation, to be at or below the cryogenic temperature;
• a transmitter of electromagnetic energy located so as, during operation, to be above the cryogenic temperature;
• switching means for switching on the transmitter from outside the cryostat;
• a receiver for the electromagnetic energy, the receiver being electrically unconnected to the transmitter and being positioned in the vicinity of the superconducting switch at a location which, during operation, is at or below the cryogenic temperature;
• storage means for chemical or mechanical energy, positioned inside the cryostat, and means associated with the receiver for causing release of the stored energy completely or partially thereby to heat the superconducting switch;
• and
• wherein the receiver is such that, upon reception of electromagnetic energy from the transmitter, the receiver effects a heating of the superconducting switch to cause it to lose its superconductivity, and thereby cause a discharge process of the superconducting magnet coil via the energy dissipation device.