| 摘要 |
PROBLEM TO BE SOLVED: To provide a cryostat where heat penetration caused by gas convection is lessened so as to enable heat to penetrates less into liquid helium. SOLUTION: A cryostat which keeps a superconductive coil 3 at cryogenic temperatures is equipped with an outer case 1 and a liquid helium tank 2 where the superconductive coil 3 independent of the outer case 1 is dipped and cooled down, wherein convection preventing plates 7 are arranged in layers between the inner wall of the outer case 1 and the outer wall of the liquid helium tank 2 so as to prevent helium gas from convecting. A space filled with gas helium is divided into small sub-spaces by the convection preventing plates 7, so that a temperature gradient become small in the same sub-space, and helium gas convection itself can be lessened. |
