Heat exchanger for cryogenic cooling apparatus

A method of forming a heat exchanger for a cryogenic refrigerator, the method comprising:

• providing a first conduit, a second conduit, a first end piece, a second end piece and a flow deflector, the flow deflector comprising a collar and a plate, the plate extending across the collar;
• wherein providing the first end piece comprises:
• fusing a first peripheral support member around the perimeter of a first foil member, and then applying a sintered material to opposing faces of the first foil member, the thermal conductivity of the first peripheral support member being at least twenty times lower than that of the first foil member when at a temperature of 300 K;
• and
• fusing the first peripheral support member to the collar so as to form a chamber, the chamber having a first region separated from a second region by the plate, the plate arranged between the first end piece and the second end piece;
• wherein the first conduit is arranged to convey a fluid into the first region and out from the second region;
• wherein the plate comprises one or more apertures for allowing a flow of the fluid from the first region to the second region;
• and
• wherein the second conduit is thermally coupled to the outside of the chamber.

A dilution refrigerator comprising:

• a still;
• a mixing chamber;
• a cold plate arranged between the still and the mixing chamber, the cold plate arranged to obtain a base temperature between that of the still and the mixing chamber during operation of the dilution refrigerator;
• a first conduit arranged to flow an operational fluid from the still to the mixing chamber;
• a second conduit is arranged to flow the operational fluid from the mixing chamber to the still;
• and
• a heat exchanger assembly comprising one or more heat exchangers arranged along a portion of the first conduit, the one or more heat exchangers extending between the cold plate and the mixing chamber;
• wherein each said heat exchanger comprises:
• a chamber arranged to receive the operational fluid from the first conduit, wherein the second conduit is thermally coupled to the outside of the chamber, the chamber having a first region and a second region, the first region separated from the second region by a plate extending through the chamber, the plate comprising one or more apertures for allowing a flow of the fluid from the first region to the second region, the heat exchanger configured to thermally couple the operational fluid in the first conduit with the operational fluid in the second conduit, and
• wherein each said chamber comprises a first end piece and a second end piece forming opposing sides of the chamber respectively, the first end piece coupled to the second end piece by a flow deflector, the flow deflector comprising a collar separating the first end piece from the second end piece, wherein the plate extends across the collar to form part of the flow deflector.

A dilution refrigerator comprising:

• a still, a mixing chamber and a heat exchanger, wherein the heat exchanger comprises:
• a first conduit, a second conduit and a chamber, wherein the first conduit is arranged to flow an operational fluid from the still to the mixing chamber and the second conduit is arranged to flow the operational fluid from the mixing chamber to the still, the heat exchanger configured to thermally couple the operational fluid in the first conduit with the operational fluid in the second conduit;
• wherein the second conduit forms the exterior of the heat exchanger,
• wherein the chamber is arranged to receive the operational fluid from the first conduit, and wherein second conduit is thermally coupled to the outside of the chamber, the chamber having a first region and a second region, the first region separated from the second region by a plate extending through the chamber, the plate comprising one or more apertures for allowing a flow of the operational fluid from the first region to the second region, and
• wherein said chamber comprises a first end piece and a second end piece forming opposing sides of the chamber respectively, the first end piece coupled to the second end piece by a flow deflector, the flow deflector comprising a collar separating the first end piece from the second end piece, wherein the plate extends across the collar to form part of the flow deflector.