Abstract: The invention relates to a system for controlling a superconducting coil (6) with a magnetic persistent current switch (7). The magnetic persistent current switch (7) is used for switching the superconducting coil (6) between a persistent mode and a ramp mode, respectively.

Abstract: An apparatus (200) includes: a cryostat (214) containing a volume of cryogenic fluid; one or more superconducting coils (202) within the cryostat; a sealed cooling system (204) within the cryostat and configured to maintain the one or more superconducting coils n a persistent state; and a second cooling system (210) having a first portion in contact with the sealed cooling system within the cryostat, a second portion extending outside of the cryostat.

Abstract: A system (100) for controlling temperature of a persistent current switch (120) operating in a background magnetic field includes a heat exchanger (138), a loop tube (135), a ball valve (245) and multiple electromagnets (251, 252). The heat exchanger disperses heat to a cryocooler (106). The loop tube enables flow of coolant to convectively transfer thermal energy generated by the persistent current switch to the heat exchanger. The ball valve is integrated with the loop tube between the persistent current switch and the heat exchanger, and contains a ferromagnetic ball (250). The electromagnets are positioned outside the loop tube adjacent to the ball valve, where energizing a first electromagnet of the multiple electromagnets magnetically moves the ferromagnetic ball to a first position opening the loop tube and enabling the flow of the coolant, and energizing a second electromagnets magnetically moves the ferromagnetic ball to a second position closing the loop tube and blocking the flow of the coolant.

Abstract: A superconducting magnet (10) includes a cryogenic container (22, 32) containing a superconducting magnet winding (20). A sealed electrical feedthrough (36) passes through the cryogenic container. A contactor (40) inside the cryogenic container has an actuator (42) and feedthrough-side and magnet-side electrical terminals (46, 47). A high temperature superconductor (HTS) lead (60) also disposed in the cryogenic container has a first end (62) electrically connected with the magnet-side electrical terminal of the contactor and a second end (64) electrically connected to the superconducting magnet winding. A first stage thermal station (52) thermally connected with the first end of the HTS lead has a temperature (T1) lower than the critical temperature (TC,HTS) of the HTS lead. A second stage thermal station (54) thermally connected with the second end of the HTS lead has a temperature (T2) lower than a critical temperature (TC) of the superconducting magnet winding (20).

Abstract: An apparatus (200) includes: a cryostat (214) containing a volume of cryogenic fluid; one or more superconducting coils (202) within the cryostat; a sealed cooling system (204) within the cryostat and configured to maintain the one or more superconducting coils n a persistent state; and a second cooling system (210) having a first portion in contact with the sealed cooling system within the cryostat, a second portion extending outside of the cryostat.

Abstract: A system (100) for controlling temperature of a persistent current switch (120) operating in a background magnetic field includes a heat exchanger (138), a loop tube (135), a ball valve (245) and multiple electromagnets (251, 252). The heat exchanger disperses heat to a cryocooler (106). The loop tube enables flow of coolant to convectively transfer thermal energy generated by the persistent current switch to the heat exchanger. The ball valve is integrated with the loop tube between the persistent current switch and the heat exchanger, and contains a ferromagnetic ball (250). The electromagnets are positioned outside the loop tube adjacent to the ball valve, where energizing a first electromagnet of the multiple electromagnets magnetically moves the ferromagnetic ball to a first position opening the loop tube and enabling the flow of the coolant, and energizing a second electromagnets magnetically moves the ferromagnetic ball to a second position closing the loop tube and blocking the flow of the coolant.

Abstract: A cryogenic cooling system (10) comprising a cryostat (12), a two-stage cryogenic cold head (24) and at least one thermal connection member (136; 236; 336; 436) that is configured to provide at least a portion of a heat transfer path (138; 238; 338; 438) from the second stage member (30) to the first stage member (26) of the two-stage cryogenic cold head (24). The heat transfer path (138; 238; 338; 438) is arranged outside the cold head (24). A thermal resistance of the provided at least portion of the heat transfer path (138; 238; 338; 438) at the second cryogenic temperature is larger than a thermal resistance of the provided at least portion of the heat transfer path (138; 238; 338; 438) at the first cryogenic temperature.

Abstract: An apparatus (100) includes: an outer shell (211); an inner vessel (212) disposed within the outer shell; a cold head (260) having a first stage (261) disposed within the outer shell, and having a second stage (262) for contacting an interior of the inner vessel; a vent (215) extending from the interior of the inner vessel to the exterior of the outer shell; first and second heat exchangers (302a, 302b); a first thermal shield (213) disposed between the inner vessel and the outer shell; and a second thermal shield (214) disposed between the inner vessel and the first thermal shield. The first thermal shield is thermally connected to the first stage of the cold head and the first heat exchanger and is thermally isolated from the inner vessel and outer shell. The second thermal shield is thermally connected to the second heat exchanger and is thermally isolated from the inner vessel, outer shell, first thermal shield, and cold head.

Abstract: A valve is configured to control a flow of a gas disposed within a convective cooling loop. The valve can be actuated between an open position and a closed position via a magnetic field generated by at least one electrically conductive coil disposed within a cryostat.

Abstract: An apparatus includes: a getter material disposed within a vacuum chamber to absorb stray molecules within the vacuum chamber; a thermal mass disposed adjacent the getter material and in thermal communication with the getter material; a cold station disposed within the vacuum chamber above the thermal mass; and a convective cooling loop connected between the thermal mass and the cold station and configured to convectively cool the thermal mass when the cold station is at a lower temperature than the thermal mass, and to thermally isolate the thermal mass from the cold station when the cold station is at a higher temperature than the thermal mass. The thermal mass may be water ice and may be thermally isolated from the walls of vacuum chamber by low loss support links and/or thermal reflective shielding.

Abstract: An apparatus includes: a getter material disposed within a vacuum chamber to absorb stray molecules within the vacuum chamber; a thermal mass disposed adjacent the getter material and in thermal communication with the getter material; a cold station disposed within the vacuum chamber above the thermal mass; and a convective cooling loop connected between the thermal mass and the cold station and configured to convectively cool the thermal mass when the cold station is at a lower temperature than the thermal mass, and to thermally isolate the thermal mass from the cold station when the cold station is at a higher temperature than the thermal mass. The thermal mass may be water ice and may be thermally isolated from the walls of vacuum chamber by low loss support links and/or thermal reflective shielding.

Abstract: An apparatus includes an electrically conductive coil which produces a magnetic field when an electrical current passes therethrough; a selectively activated persistent current switch connected across the electrically conductive coil; a cryostat having the electrically conductive coil and the persistent current switch disposed therein; an energy dump; at least one sensor which detects an operating parameter of the apparatus and outputs at least one sensor signal in response thereto; and a magnet controller. The magnet controller receives the sensor signal(s) and in response thereto detects whether an operating fault (e.g. a power loss to the compressor of a cryocooler) exists in the apparatus, and when an operating fault is detected, connects the energy dump unit across the electrically conductive coil to transfer energy from the electrically conductive coil to the energy dump unit. The energy dump unit disperses the energy outside of the cryostat.

Abstract: An apparatus includes: a getter material (310) disposed within a vacuum chamber (210) to absorb stray molecules within the vacuum chamber; a thermal mass (340) disposed adjacent the getter material and in thermal communication with the getter material; a cold station (312) disposed within the vacuum chamber above the thermal mass; and a convective cooling loop (310) connected between the thermal mass and the cold station and configured to convectively cool the thermal mass when the cold station is at a lower temperature than the thermal mass, and to thermally isolate the thermal mass from the cold station when the cold station is at a higher temperature than the thermal mass. The thermal mass may be water ice and may be thermally isolated from the walls of vacuum chamber by low loss support links (360, 362, 364) and/or thermal reflective shielding.

Abstract: A superconducting magnet (10) includes a cryogenic container (22, 32) containing a superconducting magnet winding (20). A sealed electrical feedthrough (36) passes through the cryogenic container. A contactor (40) inside the cryogenic container has an actuator (42) and feedthrough-side and magnet-side electrical terminals (46, 47). A high temperature superconductor (HTS) lead (60) also disposed in the cryogenic container has a first end (62) electrically connected with the magnet-side electrical terminal of the contactor and a second end (64) electrically connected to the superconducting magnet winding. A first stage thermal station (52) thermally connected with the first end of the HTS lead has a temperature (T1) lower than the critical temperature (TC,HTS) of the HTS lead. A second stage thermal station (54) thermally connected with the second end of the HTS lead has a temperature (T2) lower than a critical temperature (TC) of the superconducting magnet winding (20).

Abstract: A cryogenic cooling system (10) comprising a cryostat (12), a two-stage cryogenic cold head (24) and at least one thermal connection member (136; 236; 336; 436) that is configured to provide at least a portion of a heat transfer path (138; 238; 338; 438) from the second stage member (30) to the first stage member (26) of the two-stage cryogenic cold head (24). The heat transfer path (138; 238; 338; 438) is arranged outside the cold head (24). A thermal resistance of the provided at least portion of the heat transfer path (138; 238; 338; 438) at the second cryogenic temperature is larger than a thermal resistance of the provided at least portion of the heat transfer path (138; 238; 338; 438) at the first cryogenic temperature.

Abstract: An apparatus (100) includes: an outer shell (211); an inner vessel (212) disposed within the outer shell; a cold head (260) having a first stage (261) disposed within the outer shell, and having a second stage (262) for contacting an interior of the inner vessel; a vent (215) extending from the interior of the inner vessel to the exterior of the outer shell; first and second heat exchangers (302a, 302b); a first thermal shield (213) disposed between the inner vessel and the outer shell; and a second thermal shield (214) disposed between the inner vessel and the first thermal shield. The first thermal shield is thermally connected to the first stage of the cold head and the first heat exchanger and is thermally isolated from the inner vessel and outer shell. The second thermal shield is thermally connected to the second heat exchanger and is thermally isolated from the inner vessel, outer shell, first thermal shield, and cold head.

Abstract: An apparatus including a persistent current switch of a superconducting material which is electrically superconducting at a superconducting temperature and electrically resistive at a resistive mode temperature which is greater than the superconducting temperature. The apparatus further includes a first heat exchange element; a convective heat dissipation loop thermally coupling the persistent current switch to the first heat exchange element; a second heat exchange element spaced apart from the first heat exchange element; and a thermally conductive link thermally coupling the persistent current switch to the second heat exchange element. The first heat exchange element is disposed above the persistent current switch. The thermally conductive link may have a greater thermal conductivity at the superconducting temperature than at a second temperature which is greater than the superconducting temperature.

Abstract: An apparatus including an electrically conductive coil which produces a magnetic field when an electrical current passes therethrough; a selectively activated persistent current switch connected across the electrically conductive coil; a cryostat having the electrically conductive coil and the persistent current switch disposed therein; an energy dump; at least one sensor which detects an operating parameter of the apparatus and outputs at least one sensor signal in response thereto; and a magnet controller. The magnet controller receives the sensor signal(s) and in response thereto detects whether an operating fault exists in the apparatus, and when an operating fault is detected, connects the energy dump unit across the electrically conductive coil to transfer energy from the electrically conductive coil to the energy dump unit. The energy dump unit disperses the energy outside of the cryostat.

Abstract: An apparatus includes an electrically conductive coil which produces a magnetic field when an electrical current passes therethrough; a selectively activated persistent current switch connected across the electrically conductive coil; a cryostat having the electrically conductive coil and the persistent current switch disposed therein; an energy dump; at least one sensor which detects an operating parameter of the apparatus and outputs at least one sensor signal in response thereto; and a magnet controller. The magnet controller receives the sensor signal(s) and in response thereto detects whether an operating fault (e.g. a power loss to the compressor of a cryocooler) exists in the apparatus, and when an operating fault is detected, connects the energy dump unit across the electrically conductive coil to transfer energy from the electrically conductive coil to the energy dump unit. The energy dump unit disperses the energy outside of the cryostat.

Abstract: An apparatus includes: a getter material (310) disposed within a vacuum chamber (210) to absorb stray molecules within the vacuum chamber; a thermal mass (340) disposed adjacent the getter material and in thermal communication with the getter material; a cold station (312) disposed within the vacuum chamber above the thermal mass; and a convective cooling loop (310) connected between the thermal mass and the cold station and configured to convectively cool the thermal mass when the cold station is at a lower temperature than the thermal mass, and to thermally isolate the thermal mass from the cold station when the cold station is at a higher temperature than the thermal mass. The thermal mass may be water ice and may be thermally isolated from the walls of vacuum chamber by low loss support links (360, 362, 364) and/or thermal reflective shielding.