Abstract: Cooling apparatus is provided which comprises a mechanical refrigerator and a heat pipe. The mechanical refrigerator has a first cooled stage and a second cooled stage, the second cooled stage being adapted to be coupled thermally with target apparatus to be cooled. The heat pipe has a first part coupled thermally to the first stage of the mechanical refrigerator and a second part coupled thermally to a cooled member which may comprise the second stage of the mechanical refrigerator. The heat pipe is adapted to contain a condensable gaseous coolant when in use. An example coolant is Krypton. The apparatus is operated in a first cooling mode in which the temperature of the cooled member causes the coolant within the second part of the heat pipe to be gaseous and the temperature of the first stage causes the coolant in the first part to condense, whereby the cooled member is cooled by the movement of the condensed liquid from the first part to the second part of the heat pipe.

Abstract: In a cryogen cooling system for cooling a superconducting magnet, a cryogen vessel is linked to a cooling loop arrangement in thermal contact with the superconducting magnet. A recondensing chamber is arranged such that a lower extremity of the cryogen vessel is above a lower extremity of the recondensing chamber. A recondensing refrigerator is arranged to recondense cryogen gas within the recondensing chamber. A heater is positioned to heat gaseous cryogen within the recondensing chamber, and wherein the recondensing chamber is hydraulically connected to the cryogen vessel by a cryogen supply pipe. An upper end of the cryogen supply pipe is exposed to cryogen gas in the cryogen vessel and a lower end of cryogen supply pipe is exposed to an interior of the recondensing chamber towards or at its lower extremity.

Abstract: Cooling apparatus is provided which comprises a mechanical refrigerator and a heat pipe. The mechanical refrigerator has a first cooled stage and a second cooled stage, the second cooled stage being adapted to be coupled thermally with target apparatus to be cooled. The heat pipe has a first part coupled thermally to the first stage of the mechanical refrigerator and a second part coupled thermally to a cooled member which may comprise the second stage of the mechanical refrigerator. The heat pipe is adapted to contain a condensable gaseous coolant when in use. An example coolant is Krypton. The apparatus is operated in a first cooling mode in which the temperature of the cooled member causes the coolant within the second part of the heat pipe to be gaseous and the temperature of the first stage causes the coolant in the first part to condense, whereby the cooled member is cooled by the movement of the condensed liquid is from the first part to the second part of the heat pipe.

Abstract: In a method for measuring the level of liquid cryogen in a cryogen vessel, a current pulse is applied to a cryogen level probe includes an ignition current pulse part of sufficient magnitude to ensure that a resistive front propagates down the probe to below the liquid cryogen surface; a recovery current pulse part allowing that part of the superconducting wire below the surface of the liquid cryogen to return to a superconducting state; and a measurement current pulse part of sufficient magnitude and duration to allow an accurate measurement of the superconducting wire's resistance to be measured.

Abstract: In a method for measuring the level of liquid cryogen in a cryogen vessel, a current pulse is applied to a cryogen level probe includes an ignition current pulse part of sufficient magnitude to ensure that a resistive front propagates down the probe to below the liquid cryogen surface; a recovery current pulse part allowing that part of the superconducting wire below the surface of the liquid cryogen to return to a superconducting state; and a measurement current pulse part of sufficient magnitude and duration to allow an accurate measurement of the superconducting wire's resistance to be measured.

Abstract: Magnet apparatus (2) is provided comprising a magnet chamber (20), a magnet (2) positioned within the magnet chamber (20) and a quantity of superfluid coolant (30) which partially fills the magnet chamber (20) such that at least part of the magnet (2) is cooled by a superfluids film (31) of the coolant.

Abstract: A cryostat assembly includes a thermal shield, a cooling system including a cold member maintained in use at a temperature lower than that of the thermal shield, a first adsorption pump assembly located at least partly within the thermal shield, a first switch thermally connecting the adsorption pump to the thermal shield, a second switch selectively, thermally connecting the adsorption pump to the cold member, and a first thermal link. The first adsorption pump includes a pumping chamber containing a working fluid and an adsorption pump in fluid communication with the pumping chamber. The first thermal link couples the pumping chamber to the cold member. During adsorption of the working fluid by the adsorption pump, a portion of the working fluid evaporates so as to cause the temperature within the pumping chamber to fall below the temperature of the cold member.

Abstract: A cryogenic flow valve system for controlling the flow of a cryogenic fluid is disclosed. The system has a valve and an adsorption pump. The valve includes a flow chamber and a moveable member. The cryogenic fluid flows the flow chamber, and the moveable member is in contact with a control fluid. The position of the moveable member controls the flow in the flow chamber. The pressure of the control fluid controls the position of the moveable member. The adsorption pump includes a chamber and a heater. The chamber is in contact with the moveable member and contains an adsorption material for retaining control fluid. The heater heats the adsorption material to control the pressure of the control fluid.

Abstract: A method is provided of operating an adsorption refrigeration system. The system comprises a primary adsorption pump which is arranged in communication with a primary chamber containing coolant, a secondary adsorption pump and a high fluid impedance conduit which places the secondary adsorption pump and primary chamber into communication. The method comprises saturating the primary and secondary adsorption pumps with coolant whilst each pump is at its respective operational temperature. The pumps are then heated above their operational temperatures to desorb the coolant such that the coolant pressure in the primary chamber and the secondary adsorption pump substantially equalises through the conduit whilst the primary chamber is cooled. The secondary adsorption pump is then cooled causing coolant gas to be adsorbed and therefore a reduction in temperature and pressure of the coolant in the primary chamber is effected.

Abstract: An adsorption refrigeration system and method are provided, the system comprising an adsorption pump which, in use, is arranged in communication with a chamber containing liquid and gaseous coolant. The associated method comprises expanding the gaseous coolant into an auxiliary volume member so as to cause the removal of part of the gaseous coolant from the chamber. This causes a reduction in the temperature and pressure of the gaseous coolant in the chamber. The adsorption pump is then operated so as to further cool the chamber by causing the evaporation of the coolant liquid within the chamber.