Cryocooler and cryogenic system

A cryocooler comprising:

• 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;
• a cooling stage that is disposed inside the recondensing chamber when the attachment flange is attached to the recondensing chamber, and cooled to a cryogenic temperature which enables the refrigerant gas to be condensed;
• and
• a regenerator tube that connects the attachment flange to the cooling stage,
• wherein the refrigerant gas introduction port includes a plurality of holes formed on the attachment flange and around the regenerator tube, the plurality of holes arranged radially outward of an outer circumferential surface of the regenerator tube.

A cryogenic system comprising:

• a recondensing chamber that accommodates a cooling stage of a cryocooler;
• and
• a refrigerant gas introduction port installed in the recondensing chamber, and introducing refrigerant gas into the recondensing chamber from an ambient temperature environment,
• wherein the refrigerant gas introduction port is perpendicularly or obliquely oriented with respect to an axial direction of the cryocooler and a center line of the refrigerant gas introduction port extends not to intersect the cooling stage such that a refrigerant gas flow exiting the refrigerant gas introduction port deviates from the cooling stage.