| 摘要 |
PROBLEM TO BE SOLVED: To resolve problems in a conventional type pressurized superfluid helium cryostat wherein a heat flow to a superfluid helium tank is generated by heat conduction of a support structure between a 4.2K liquid helium tank and a superfluid helium tank and liquid helium existing in a wall or a passage of a communication passage between the two, a temperature of the 4.2K liquid helium tank is lowered, and as a result, dropping of a liquid level of the 4.2K liquid helium tank is caused, a coolant replenishment interval is shortened. SOLUTION: In the cryostat equipped with the 4.2K liquid helium tank storing liquid helium, the superfluid helium tank storing liquid helium with a lower temperature than the liquid helium, and a heat shield cooled by evaporation gas of the 4.2K liquid helium tank and suppressing heat radiation to the 4.2K liquid helium tank from the outer world, a heat switch using gas is installed between the heat shield and the 4.2K liquid helium tank. By this, the temperature of the 4.2K liquid helium tank is raised, and shortening of the coolant replenishment interval is suppressed. COPYRIGHT: (C)2009,JPO&INPIT |
