Abstract: A counter flow heat exchanger comprising a body formed of stacked, fused, ceramic sheets. The sheets comprising: a bottom sheet, a second sheet, a third sheet, a fourth sheet and a top sheet. The sheets have punched holes such that when the sheets are aligned there is an inlet hole spanning from the top sheet to the fourth sheet, an outlet hole spanning from the top sheet to the second sheet, and an inflow hole spanning from the fourth sheet to the second sheet. Within the second sheet, a low pressure flow channel connects the outlet hole with the inflow hole. Within the fourth sheet, the inlet hole flows into a high pressure flow channel which flows into a narrow flow path which then empties into the inflow hole. The high pressure flow channel is aligned with the low pressure flow channel to allow for heat exchange.

Abstract: A cryostat assembly includes a first thermal shield positioned outside a working volume and a second thermal shield positioned outside the first thermal shield. A first cryocooler has at least two cooling stages operating with He4, a first stage of the cryocooler being thermally coupled to the second thermal shield, and a second stage of the first cryocooler being thermally coupled to the first thermal shield. A second cryocooler operates with He3 and has at least one cooling stage, a part of the second cryocooler, warmer than the cooling stage of the second cryocooler, being thermally coupled to the second stage of the first cryocooler.

Abstract: A cryostat assembly comprises a liquid coolant containing vessel; a mechanical cooler having at least one cooling stage located above the vessel; and a channel for conveying gaseous coolant from the vessel to the cooling stage where the coolant is condensed in use and then returns through the channel to the vessel. An acoustic wave attenuator is located in the channel for attenuating the passage of acoustic energy originating from the mechanical cooler and propagating through the gaseous coolant, while permitting flow of gaseous coolant to the cooling stage and flow of condensed coolant to the vessel.

Abstract: Cooling apparatus comprises a vacuum chamber, an inner chamber positioned within the vacuum chamber adapted to contain a coolant for cooling target apparatus, and a mechanical refrigerator for refrigerating the coolant and having at least one cooled part in contact with the coolant. The mechanical refrigerator is coupled to one or each of the vacuum chamber and inner chamber through vibration-reducing couplings, so as to reduce the effect upon the target apparatus of vibrations from the mechanical refrigerator.

Abstract: A magnetic field generating assembly comprises a superconducting magnet located in a cryostat defining a bore accessible from outside the cryostat, and a mechanical refrigerator having at least two cooling stages for at least partly cooling the cryostat. A coolant path extends from the refrigerator into the magnet bore. The coolant path is coupled for heat exchange with a cooling stage of the refrigerator other than the coldest cooling stage, so that the refrigerator is adapted also to cool coolant in the coolant path.