Abstract: A system and method for de-icing a recondensor includes at least one heating element configured to melt iced particles from a recondensing system. A power delivery circuit is included configured to deliver power to the at least one resistive heating element such that the at least one resistive heating element delivers a supply of heat sufficient to melt the iced particles from the recondensing system.

Abstract: A thermal shield for a superconducting magnet includes a shield body having an annular shape. The shield body includes a material having a thermal conductivity greater than about 1000 W/m·K at about 70K.

Abstract: A zero boiloff cryogen cooled recondensing superconducting magnet assembly including superconducting magnet coils suitable for magnetic resonance imaging including a cryogen pressure vessel to contain a liquid cryogen reservoir to provide cryogenic temperatures to the magnet coils for superconducting operation; a vacuum vessel surrounding the pressure vessel and spaced therefrom; a first thermal shield surrounding and spaced from the pressure vessel; a second thermal shield surrounding and spaced from the first thermal shield and intermediate the vacuum vessel and the first shield; a cryocooler thermally connected by a first and a second thermal interface to the first and second thermal shields, respectively; a recondenser positioned in the space between the pressure vessel and the first thermal shield and thermally connected by a thermal interface to the cryocooler to recondense, back to liquid, cryogen gas provided from the pressure vessel; and means for returning the recondensed liquid cryogen the pressure

Abstract: A magnetic resonance imaging magnet assembly is provided. The assembly comprises a outer thermal shield having an operational temperature. The assembly further includes a cold sleeve assembly comprising a plurality of braid elements mounted to a cooler block and a highly thermally conductive block mounted between the cooler block and the outer thermal shield. The highly thermally conductive block is welded to the outer thermal shield and is welded to the cooler block. The highly thermally conductive block has greater thermal conductance than the outer thermal shield.

Abstract: A system and method for de-icing a recondensor includes at least one heating element configured to melt iced particles from a recondensing system. A power delivery circuit is included configured to deliver power to the at least one resistive heating element such that the at least one resistive heating element delivers a supply of heat sufficient to melt the iced particles from the recondensing system.

Abstract: A low eddy current cryogen circuit for superconducting magnets including at least a first cooling coil made of an electrically conducting material and having at least one electrical isolator incorporated in the first cooling coil. The electrical isolator is located to inhibit induced eddy current loops due to inductive coupling of the first cooling coil with eddy current inducing field sources.

Abstract: A Magnetic Resonance Imaging (MRI) magnet field instability simulator (80) is provided. The simulator includes a rigid body motion generator (82) that simulates motion of one or more MRI system components. An eddy current analyzer (84) generates a magnetic stiffness and damping signal and an electromagnetic transfer function in response to the motions and a cryostat material properties signal. A mechanical model generator (86) generates a mechanical disturbance signal and a mechanical model of one or more MRI system components in response to the motions and the magnetic stiffness and damping signal. A structural analyzer (88) generates a motion signal in response to the mechanical model. A field instability calculator (90) generates a field instability signal in response to the electromagnetic transfer function and the motion signal. A method of performing the same is also provided.

Abstract: A magnetic resonance assembly comprising, a liquid cryogen vessel, a liquid cryogen cooled conducting magnet disposed within the liquid cryogen vessel, a closed vaccum vessel surrounding the liquid cryogen vessel and spaced from the liquid cryogen vessel, a cooling device fixably attached to the vacuum vessel operable for providing cryogenic temperatures to the superconducting magnet, a heat exchanger device in thermal contact with the liquid cryogen vessel operable for heat exchange, and a bus bar in thermal contact with the cooling device and the heat exchanger device. The cooling device may be a pulse tube cryocooler capable of providing temperatures of about 4 K. A thermal bus bar of high purity aluminum or copper is used to connect and provide a spatial separation of a pulse tube cryocooler and a remote recondenser unit, thus reducing the overall height of the magnet assembly.

Abstract: A magnetic resonance assembly comprising, a liquid cryogen vessel, a liquid cryogen cooled superconducting magnet disposed within the liquid cryogen vessel, a closed vacuum vessel surrounding the liquid cryogen vessel and spaced from the liquid cryogen vessel, a cooling device fixably attached to the vacuum vessel operable for providing cryogenic temperatures to the superconducting magnet, a heat exchanger device in thermal contact with the liquid cryogen vessel operable for heat exchange, and a bus bar in thermal contact with the cooling device and the heat exchanger device. The cooling device may be a pulse tube cryocooler capable of providing temperatures of about 4 deg K. A thermal bus bar of high purity aluminum or copper is used to connect and provide a spatial separation of a pulse tube cryocooler and a remote recondensor unit, thus reducing the overall height of the magnet assembly.

Abstract: A Magnetic Resonance Imaging (MRI) magnet field instability simulator (80) is provided. The simulator includes a rigid body motion generator (82) that simulates motion of one or more MRI system components. An eddy current analyzer (84) generates a magnetic stiffness and damping signal and an electromagnetic transfer function in response to the motions and a cryostat material properties signal. A mechanical model generator (86) generates a mechanical disturbance signal and a mechanical model of one or more MRI system components in response to the motions and the magnetic stiffness and damping signal. A structural analyzer (88) generates a motion signal in response to the mechanical model. A field instability calculator (90) generates a field instability signal in response to the electromagnetic transfer function and the motion signal. A method of performing the same is also provided.

Abstract: A mechanical stabilizer-tuned damper is attachable to the first upper magnet assembly of a high field open magnet, which magnet includes a first upper magnet assembly, a lower second magnet assembly and at least one non-magnetizable support beam therebetween. The mechanical stabilizer-tuned damper reduces the dynamic response of the magnet. A connecting device is provided which consists of a threaded rod mounted to an attachment bracket through a linear bearing and vibration mount. A series of non-magnetic and extremely low conductivity plates of various weights are attachable to the rod to change the mass and the tuning frequency of the damper. The location and size of the mechanical stabilizer-tuned damper are determined to balance the frequency of the field oscillation and physical room. The direction of orientation depends upon the direction of motion to be dampened or controlled.

Abstract: A secure and stable mounting system for High Field Open (HFO) magnets. A stainless steel mounting plate is secured to the RF screen room floor and the HFO magnet is secured to the mounting plate. Metal angle members are welded around the perimeter edges of the steel plate, and brass wool is inserted between the angle members and the copper sheeting on the floor of the screen room. The invention minimizes magnet motion and thus reduces the risk of image phase ghosting. The invention also provides RF screen room integrity.

Abstract: A new design for an aluminum stabilized superconductor which embeds the superconducting cable within a high purity aluminum stabilizer. This stabilizer is, in turn, partially surrounded by an aluminum alloy sheath. The aluminum alloy sheath is constructed and arranged so that at least one exterior surface of the stabilizer is open for exposure to a coolant. Preferably, this open exterior surface of the stabilizer will be knurled for greater cooling efficiency.

Abstract: A common heat acceptor is provided between opposed displacers in a Stirling cycle machine. It includes two sets of open channels in separate fluid communications with the expansion spaces of the receptive cyclinders. The channels confine movement of working fluid in separate paths that extend between the expansion space of one cylinder and the compression space of the other. The method for operating the machine involves alternatively directing working fluid from the expansion space of each cylinder in a fluid path leading to the compression space of the other cylinder and from the compression space of each cylinder in a fluid path leading to the expansion space of the other cylinder.