Cryostat with liquefaction refrigerator

In a cryostat with a liquefaction refrigerator which contains an object to be cooled, as well as a low-temperature end of said liquefaction refrigerator for cooling said object to be cooled, is contained in a thermally-insulated space;

• the improvement wherein said liquefaction refrigerator comprises a cooler and a refrigerator;
• said cooler comprises, as main components, a heat exchanger and an expansion valve;
• said refrigerator includes mechanically-operated cold-generating means;
• a compressor for supplying an operating fluid to said refrigerator is provided at an ordinary-temperature portion;
• an adsorbent device for adsorbing impurities in said operating fluid is provided at a low-temperature end of said refrigerator disposed in said thermally-insulated space;
• there is provided a communication passage for supplying said operating fluid, passed through said adsorbent device, from an ordinary-temperature end of said cooler;
• and within said thermally-insulated space, said cooler and said refrigerator are thermally connected together by releasable thermally-conductive means.