Multistage low-temperature refrigeration machine

A cryostat used in conjunction with a multistage low-temperature refrigeration machine, said cryostat having a housing for retaining an object to be cooled, said machine comprising a first stage in the form of a displacer refrigerator, at least one additional stage in the form of a pulse tube refrigerator, and a flexible component located between the displacer refrigerator and the pulse tube refrigerator for preventing the spread of vibrations between said stages, said cryostat including a shielding stage thermally coupled to at least one of a cold end of the displacer refrigerator and a warm end of the pulse tube refrigerator, and in which the object to be cooled is thermally coupled to a cold end of the pulse tube refrigerator wherein the object to be cooled is a tank filled with liquid helium, and in which the cold end of the pulse tube refrigerator is thermally coupled to a helium re-filling port of the tank.

A multistage low-temperature refrigeration machine comprising a first stage in the form of a displacer refrigerator;

• at least one additional stage in the form of a pulse tube refrigerator;
• and a flexible component located between the displacer refrigerator and the pulse tube refrigerator, for preventing the spread of vibrators between said stages, and in which the flexible component is part of a gas supply line for the pulse tube refrigerator, wherein the gas supply line is connected to a cold end of a working area defined within said displacer refrigerator.

A cryostat used in conjunction with a multistage low-temperature refrigeration machine, said cryostat having a housing for retaining an object to be cooled, said machine comprising a first stage in the form of a displacer refrigerator, at least one additional stage in the form of a pulse tube refrigerator, and a flexible component located between the displacer refrigerator and the pulse tube refrigerator for preventing the spread of vibrations between said stages, said cryostat including a shielding stage thermally coupled to at least one of a cold end of the displacer refrigerator and a warm end of the pulse tube refrigerator, and in which the object to be cooled is thermally coupled to a cold end of the pulse tube refrigerator, wherein said shielding stage includes a thermal link portion for linking with the warm end of the pulse tube refrigerator, and a second flexible component for preventing the spread of vibrations, said second flexible component being provided between the thermal link portion and the remainder of the shielding stage.

A cryostat used in conjunction with a multistage low-temperature refrigeration machine, said cryostat having a housing for retaining an object to be cooled, said machine comprising a first stage in the form of a displacer refrigerator, at least one additional stage in the form of a pulse tube refrigerator, and a flexible component located between the displacer refrigerator and the pulse tube refrigerator for preventing the spread of vibrations between said stages, said cryostat including a shielding stage thermally coupled to at least one of a cold end of the displacer refrigerator and a warm end of the pulse tube refrigerator, and in which the object to be cooled is thermally coupled to a cold end of the pulse tube refrigerator wherein, the object to be cooled is a magnet made of a superconducting material wherein the warm end of the pulse tube thermometer is coupled to the shielding stage in addition to the cold end of the displacer refrigerator.