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 multi purpose interconnect assembly between upper and lower helium vessels in a recondensing superconducting magnet to provide isothermal connections to extend the ride-through period, and to provide for helium liquid and gas passage, electrical interconnections, and to accommodate differential thermal contraction and expansion.

Abstract: Vibration and noise isolation for a magnetic resonance imager (MRI) superconducting magnet cryocooler includes a bellows between the cryocooler and its vacuum sleeve in the magnet, a mass suspended along the axis of, but at a distance from, the cryocooler, elastomeric blocks parallel to the axis, and braided copper wires connecting the vacuum sleeve and the heat shields of the MRI. Motion limiters and bellows flexures are provided for dynamic loads which might be encountered during transport of the magnet.

Abstract: A flexible heat transfer assembly between a cryogenic refrigerator cold head sleeve and magnetic resonance imager thermal shields includes a plurality of rope-lay stranded copper ropes, each containing a large number of section.

Abstract: A system is provided for controllably venting cryogen of extremely low temperature from a cryostat, wherein a conduit formed of selected metal provides a path of flow for the cryogen from the cryostat to an exhaust system. A gauge is coupled to the conduit, along the path of flow, by means of a bushing which thermally isolates the gauge from the metallic conduit, which is at an extremely low temperature. Thus, the gauge, which is used to continually monitor cryogen pressure, does not become unreadable due to icing or frosting as a result of heat loss from the gauge to the conduit. The bushing is formed from a material such as GC-10, and includes an intermediate portion for spacing the bushing away from the metallic conduit, and also for enclosing a dead space which substantially reduces heat transfer directly between the gauge and cryogen in the conduit.