Cryogenic refrigeration installation and method

A cryogenic refrigeration installation comprising:

• an enclosure delimiting a sealed volume closed by a cover, the enclosure accommodating at least two thermally conductive trays distributed in a distribution direction in the enclosure and forming thermal stages, at least one of the two thermally conductive trays being connected to a heat shield forming a thermal insulation volume;
• a cooling system configured to cool to a cryogenic temperature by cooling at least some of the thermally conductive trays and/or one or more plate(s) connected to the thermally conductive trays and forming a support for a set of cable(s) or samples to be cooled,
• wherein the cooling system comprises a refrigerator that is configured to perform a refrigeration cycle on a cycle fluid, said refrigerator comprising a cycle circuit containing a cycle fluid comprising helium, the cycle circuit being configured to subject the cycle fluid to a thermodynamic cycle bringing the cycle fluid at at least a cold end of the cycle circuit to a determined cold temperature, the cycle circuit placing a flow of cycle fluid at the cold end in heat exchange with at least some of the thermally conductive trays and/or plates,
• wherein the cycle circuit further comprises a compression mechanism configured to compress the cycle fluid, a cooling member configured to cool the cycle fluid, an expansion mechanism configured to expand the cycle fluid and a heating member configured to heat the expanded cycle fluid,
• wherein the cycle circuit further comprises:
• a first storage vessel configured to store a reserve of liquefied cycle fluid;
• downstream of the heat exchange with at least some thermally conductive trays and/or plates;
• a bypass line configured to divert at least some of the flow of cycle fluid to the first storage vessel, the bypass line comprising a bypass expansion member configured to expand the flow of cycle gas before feeding the first storage vessel;
• upstream of the heat exchange with at least some thermally conductive trays and/or plates, a portion in heat exchange with the liquefied cycle fluid contained in the first storage vessel;
• downstream of the passage inside the first storage vessel, at least one first line located in the enclosure exchanging heat with at least some thermally conductive trays and/or plates;
• and
• a second bypass line for the first line, the second bypass line being located in the enclosure and provided with a second bypass expansion member configured to expand the cycle fluid in order to produce a colder flow of bypass cycle fluid at a temperature of between 1 and 2 K, said bypass cycle fluid being placed in heat exchange with at least one additional thermally conductive tray or plate of the installation.