Patent ID: 7310954

Claim:
A cryogenic system comprising: a cryocooler unit; an element to be cooled; a cooling stage of said cryocooler unit, said cooling stage being provided so that a space formed between said cooling stage of said cryocooler unit and said element to be cooled; and a thermal joint placed in said space, wherein said thermal joint is composed of a substance that has a melting point higher than the cooling temperature of said element to be cooled and that is in a liquid or gaseous state at room temperature and atmospheric pressure, and wherein said thermal joint functions as a thermal switch which is on when the substance is in a solid state, the substance of the thermal joint is in a solid state when the cryocooler unit is in operation, and in a liquid or gaseous state when the cryocooler unit is at rest, and the substance contains at least one selected from the group consisting of nitrogen, neon, para-hydrogen, and water.