Abstract: Disclosed are a helium gas liquefier and a method for liquefying a helium gas. The disclosed helium gas liquefier includes: a first cooling part including a first cooling column; a first cold head installed on the first cooling column, and a first cylinder in which the first cooling column and the first cold head are built; a second cooling part including a second cooling column, a second cold head installed on the second cooling column, and a second cylinder in which the second cooling column and the second cold head are built; and a liquid helium storage disposed under the second cooling part.

Abstract: A two-phase thermodynamic system includes a porous microstructure sheet to increase an aggregate thin-film evaporation area of a working fluid. The porous microstructure sheet may be disposed at a liquid-vapor boundary of the working fluid. The porous microstructure sheet has “micro” pores through which the working fluid flows from a liquid flow path on one side of the porous microstructure sheet to a vapor flow path on the other side of the porous microstructure sheet. Individual pores induce the working fluid to form thin-film evaporation regions. The porous microstructure sheet may have a pore density so as to increase an aggregate thin-film evaporation area of the working fluid. In this way, the overall thermal resistance across all liquid-vapor interfaces (menisci) of the working fluid is substantially decreased over conventional vapor chamber.

Abstract: The present disclosure relates to a cryocooling system and method. The system includes a sample well and a sample chamber, each of which having an interior that is sized and shaped to hold a cryocooling gas at cryogenic temperatures and a pressure below 1 atm. The sample chamber is also sized and shaped to hold a sample substance to be cryocooled. An impedance tube connects the interior of the sample well to the interior of the sample chamber to allow cryocooling gas to move from the sample well to the sample chamber. A vacuum tube is connected to the interior of the sample chamber on one side and to a vacuum pump via a vacuum port on the other. The vacuum tube is sized and shaped to allow cryocooling gas within the sample chamber to be pumped out of the sample chamber by the vacuum pump.

Abstract: Cryogenic refrigeration employs a pulse tube cryo-cooler and a dilution refrigerator to provide very low temperature cooling, for example, to cool superconducting processors. Continuous cryogenic cycle refrigeration may be achieved using multiple adsorption pumps. Various improvements may include multiple distinct thermal-linking points, evaporation pots with cooling structures, and/or one or more gas-gap heat switches which may be integral to an adsorption pump. A reservoir volume may provide pressure relief when the system is warmed above cryogenic temperature, reducing the mass of the system. Additional heat exchangers and/or separate paths for condensation and evaporation may be provided. Multi-channel connectors may be used, and/or connectors formed of a regenerative material with a high specific heat capacity at cryogenic temperature. Flexible PCBs may provide thermal links to components that embody temperature gradients.

Abstract: Systems and methods from removing heat generated by a heat sink of a magnetic resonance imaging (MRI) system are provided. One system includes a coldhead sleeve cooling arrangement for a coldhead of the MRI system. The coldhead sleeve cooling arrangement includes a coldhead sleeve configured to receive therein a coldhead of an MRI system and a cooling system surrounding an outer surface of the coldhead sleeve. The cooling system uses helium gas to remove heat from the coldhead sleeve.

Abstract: A helium recovery plant adapted to filter, compress, and purify helium gas collected from one or more helium-using instruments, as well as to liquefy and redistribute the purified gas within a closed system. The recovery plant is adapted to match the purification and liquefaction rate of the system with the consumption rate of the coupled instruments. Additionally, the recovery plant is adapted to match the liquefaction rate of a liquefaction module with a boil-off rate of liquid helium within a Dewar thereof. The recovery plant is further adapted to recycle helium therein in an effort to achieve zero loss.

Abstract: A system and method for recovering helium-3 from helium. A distillation column having a top section that is smaller in diameter than a main section is provided. The column also includes an intermediate condenser that condenses vapor from the main section and above a helium feed stream. Reflux to the column can be provided by liquid helium-3 from a conduit or from an overhead condenser. In a preferred cycle, the distillation column is operated at a subatmospheric pressure, and in a temperature range between 2.3 K and 4.3 K.

Abstract: A system and method for recovering helium-3 from helium. A distillation column having a top section that is smaller in diameter than a main section is provided. The column also includes an intermediate condenser located in the main section and above a helium feed stream. Reflux to the column can be provided by liquid helium-3 from a conduit or from an overhead condenser. In a preferred cycle, the distillation column is operated at a subatmospheric pressure, and in a temperature range between 2.3 K and 4.3 K.

Abstract: Cryogenic refrigeration employs a pulse tube cryo-cooler and a dilution refrigerator to provide very low temperature cooling, for example, to cool superconducting processors. Continuous cryogenic cycle refrigeration may be achieved using multiple adsorption pumps. Various improvements may include multiple distinct thermal-linking points, evaporation pots with cooling structures, and/or one or more gas-gap heat switches which may be integral to an adsorption pump. A reservoir volume may provide pressure relief when the system is warmed above cryo genic temperature, reducing the mass of the system. Additional heat exchangers and/or separate paths for condensation and evaporation may be provided. Multi-channel connectors may be used, and/or connectors formed of a regenerative material with a high specific heat capacity at cryogenic temperature. Flexible PCBs may provide thermal links to components that embody temperature gradients.

Abstract: The invention relates to a method for producing very low temperature cold through a dilution cycle wherein a two-phase mixture of the two isotopes 3He and 4He is created in a mixing chamber from liquid 3He and 4He added separately, wherein said mixture of the 3He from a so-called concentrated phase is extracted so as to pass 3He into a so-called diluted phase, and due to which the cold energy generated by passing the 3He into the diluted phase is recovered, the phase separation of the two-phase mixture being carried out by monitoring the flows of pure 3He and 4He, added separately into the mixing chamber, and by gravity-independent capillary forces, the dilution cycle operating in a closed loop, the method including a first step of recovering and separating the two isotopes 3He and 4He from the fraction of the mixture extracted through a discharge duct; and a second step of adding the two isotopes 3He and 4He, separated during the first step, back into the mixing chamber.

Abstract: A dilution refrigerator assembly comprises a first module (1) including a dilution refrigerator (2); and a second module (3) including experimental services for attachment to a sample located in use outside the dilution refrigerator (2). The second module (3) can be attached to and demounted from the first module (1) without compromising the integrity of the dilution refrigerator.

Abstract: A dilution refrigerator assembly comprises a first module (1) including a dilution refrigerator (2); and a second module (3) including experimental services for attachment to a sample located in use outside the dilution refrigerator (2). The second module (3) can be attached to and demounted from the first module (1) without compromising the integrity of the dilution refrigerator.

Abstract: A resilient multi-layer container is configured to receive a quantity of hyperpolarized noble fluid such as gas and includes a wall with at least two layers, a first layer with a surface which minimizes contact-induced spin-relaxation and a first or second layer which is substantially impermeable to oxygen. The container is especially suitable for collecting and transporting 3He. The resilient container can be formed of material layers which are concurrently responsive to pressure such as polymers, deuterated polymers, or metallic films. The container can include a capillary stem and/or a port or valve isolation means to inhibit the flow of gas from the main volume of the container during transport. The resilient container can be configured to directly deliver the hyperpolarized noble gas to a target interface by deflating or collapsing the inflated resilient container.

Abstract: A process for preparing hyperpolarized helium gas at high pressure including optical pumping at a resonant wavelength of about 1083 nanometers a helium gas formed by pure helium-3 isotope or by a mixture of helium-3 and helium-4 isotopes; and subjecting the helium gas to a magnetic field of about 0.01 to about 1 tesla during optical pumping and maintaining pressure higher than about 10 mbar and an apparatus for preparing a hyperpolarized helium gas at high pressure including a helium gas confinement cell; an excitation laser positioned to irradiate the helium gas; and means for generating a magnetic field of about 0.01 to about 1 tesla operatively connected to the confinement cell.

Abstract: A dilution refrigerator includes a still; a mixing chamber; a pump to pump coolant from the still through a still outlet port and a heat exchanger connected between the still and mixing chamber whereby coolant flows under the assistance of the pump from the still to the mixing chamber and from the mixing chamber to the still through respective first and second adjacent paths in the heat exchanger. An access path extends to the mixing chamber. A probe is provided for insertion along the access path, the probe having a displacer which substantially fills the cross-section of the access path in use. Any coolant from the mixing chamber which flows along the access path past the displacer can flow from the access path into the still. The still outlet port is separate from the access path.

Abstract: A resilient container configured to receive a quantity of hyperpolarized noble gas includes a wall with at least two layers, a first layer with a surface which minimizes spin-relaxation and a first or second layer which is substantially impermeable to oxygen. The container is especially suitable for collecting and transporting .sup.3 He. The resilient container can be configured to directly deliver the hyperpolarized noble gas to a target interface by deflating or collapsing the inflated resilient container. Related collection and transporting methods include forming the wall of the container and collecting the hyperpolarized gas in a way which minimizes its exposure to de-polarizing impurities. Also, a container includes a quantity of polarized gas and extends the T.sub.1 life by configuring the wall of the container with a controlled thickness of the surface coating and overlays the interior with an exterior which is substantially impermeable to oxygen.

Abstract: A refrigerator for cooling a sample (16,17) comprising a reservoir (1) for storing gaseous .sup.4 He when in use; a cooler (13) for cooling gaseous .sup.4 He from the reservoir; and a helium vessel (18,19) for containing .sup.4 He, the .sup.4 He in the helium vessel being in fluid communication with the reservoir (1) via the cooler (13). The sample (16,17) is mounted, in use, in thermal contact with the .sup.4 He in the helium vessel whereby the .sup.4 He in the helium vessel provides a path for heat to transfer from the sample to the cooler.

Abstract: A refrigerator for cooling a sample comprises a container for holding liquid helium refrigerant to cool the sample. First cooling means is provided for cooling a condensation region with liquid helium coolant whereby helium refrigerant condenses on the condensation region and collects in the container. A sorption pump pumps gaseous helium refrigerant from the container. Second cooling means is provided for cooling the sorption pump with the liquid helium coolant. The first and second cooling means are connected in series with a source of the liquid helium coolant.

Abstract: Dilution refrigerator equipment, which includes a vacuum vessel with its connections, a dilution refrigerator, made essentially completely of plastic set inside it and supported from a metallic pumping tube, includes an upper still and a lower mixing chamber and a heat exchanger connecting them. The pumping tube is connected to the still of the dilution refrigerator. The tube connection of the still includes an intermediate piece, separating the metallic pumping tube from the plastic structure of the still, which is made from a mixture of plastic and metal powder, to accommodate the greatly deviating thermal expansions of the connection components to one another.

Abstract: Temperatures of 0.2.degree. K or lower are achieved by feeding 3He and 4He separately into a mixing chamber (5) in an enclosure (3) in which the temperature is held at around 2.degree. K. The endothermal dilution of 3He into 4He provides the required cold. The resulting mixture (M) passes out of the mixing chamber and the enclosure while cooling the incoming fluids by means of exchangers (1, 12, 4). To compensate for thermal losses, the mixture (M) also undergoes Joule-Thompson expansion (12) optionally followed by evaporation (13), preferably between about 1.5.degree. and 2.5.degree. K, and the resulting cold is used to lower the temperature of the incoming fluids from well above 4.degree. K to between 1.5.degree. and 2.5.degree. K, which is close to the temperature prevailing inside the enclosure (13) containing the coldest point (6) in the circuit.

Abstract: A sample holding device (30) for a dilution refrigerator having a still (16), a mixing chamber (22), and a heat exchanger (26) connected between the still and mixing chamber whereby coolant flows from the still to the mixing chamber and from the mixing chamber to the still through respective first and second adjacent paths in the heat exchanger and wherein the mixing chamber has a tubular portion (27), the sample holding device comprising a tube for insertion in the tubular portion of the mixing chamber and having means (34) for holding a sample within the tubular portion, the tube having an aperture (36) adjacent the sample holding means communicating in use between the interior of the tube and the interior of the tubular portion and another aperture (37) positioned in use to communicate between the interior of the tube and the second path in the heat exchanger.