There is provided a cryocooler including a cryocooler cylinder, a pressure switching valve that generates a periodic pressure fluctuation inside the cryocooler cylinder, and a sensor that measures a periodic deformation of the cryocooler cylinder, which is caused by the periodic pressure fluctuation inside the cryocooler cylinder.

There is provided a mounting structure for mounting a cryocooler cold head on a vacuum vessel. The cold head includes a cold head-side cooling stage and a cold head-side flange. The mounting structure includes a cold head accommodation sleeve installed in the vacuum vessel and including a sleeve-side cooling stage which comes into thermal contact with the cold head-side cooling stage by coming into physical contact with the cold head-side cooling stage, and a sleeve-side flange to be coupled to the cold head-side flange, an inter-flange distance adjustment mechanism configured to adjust a distance between the sleeve-side flange and the cold head-side flange so that the cold head-side cooling stage and the sleeve-side cooling stage are physically brought into contact with each other or brought into a contactless state therebetween, and a flange fastening mechanism configured to fasten the cold head-side flange to the sleeve-side flange.

A cryocooler includes an attachment flange including a refrigerant gas introduction port through which refrigerant gas is introduced into a recondensing chamber from an ambient temperature environment, and attachable to the recondensing chamber, and a cooling stage that is disposed inside the recondensing chamber when the attachment flange is attached to the recondensing chamber. The refrigerant gas introduction port is perpendicularly or obliquely oriented with respect to an axial direction of the cryocooler so that a refrigerant gas flow exiting the refrigerant gas introduction port deviates from the cooling stage.

A pulse-tube cryocooler includes a compressor piston that is axially aligned with a pulse tube. The compressor piston is an annular piston that has a central hole around its axis. An inertance tube, connected to one end of the pulse tube, runs through the central hole in the compressor piston. The cryocooler also includes a balancer that moves in opposition to the compressor piston, to offset the forces in moving the compressor piston. The balancer may also be axially aligned with the pulse tube, the annular piston, and the inertance tube. The alignment of the compressor piston, the pulse tube, and the inertance tube aligns the forces produced by movement of fluid within the cryocooler.

A compact, low power cryo-cooler for cryogenic systems capable of cooling gas to at least as low as 2.5 K. The cryo-cooler has a room temperature compressor followed by filtration. Within the cryostat, four counterflow heat exchangers precool the incoming high-pressure gas using the outflowing low-pressure gas. The three warmest heat exchangers are successively heat sunk to three stages of a pulse tube to absorb residual heat from the slight ineffectiveness of the heat exchangers. The pulse tube cold head also absorbs loads from instrumentation leads and radiation loads. The pulse tube stages operate at around 80 K, 25 K, and 10 K. The entire systemcryo-cooler, drive and control electronics, and detector instrumentation, fits in a standard electronics rack mount enclosure, and requires around 300 W or less of power.

A pulse tube cryocooler includes: a pulse tube having a pulse tube high-temperature end and a pulse tube low-temperature end, and extending in an axial direction from the pulse tube high-temperature end to the pulse tube low-temperature end; a regenerator having a regenerator high-temperature end and a regenerator low-temperature end, and being disposed rowed alongside the pulse tube, with the regenerator high-temperature end being positioned displaced, in terms of the axial direction, from the pulse tube high-temperature end toward the cryocooler low-temperature side, and the regenerator low-temperature end being fluid-passage linked with the pulse tube low-temperature end; and a pressure-switching valve for connecting the regenerator high-temperature end to a high-pressure source and to a low-pressure source in alternation, and being disposed between the pulse tube high-temperature end and the regenerator high-temperature end in terms of the axial direction.

A pulse-tube cryocooler includes a compressor piston that is axially aligned with a pulse tube. The compressor piston is an annular piston that has a central hole around its axis. An inertance tube, connected to one end of the pulse tube, runs through the central hole in the compressor piston. The cryocooler also includes a balancer that moves in opposition to the compressor piston, to offset the forces in moving the compressor piston. The balancer may also be axially aligned with the pulse tube, the annular piston, and the inertance tube. The alignment of the compressor piston, the pulse tube, and the inertance tube aligns the forces produced by movement of fluid within the cryocooler. This makes it easier to cancel mechanical forces produced by the cryocooler in operation, since all (or most) of the forces are in a single axial direction.