PURPOSE:To make the height of the entire body low, by providing a pipe, whose one end is communicated to the upper space of a refrigerant container and other end is positioned at a normal temperature part, in a U shape in such a way that a part of the pipe rises up through the range of the height of the refrigerant container. CONSTITUTION:A pipe 6a,which is used for injection of liquid helium, recovery of helium gas, guide of gas cooling current leads and the like, is composed of a part 12 and a part 13. The part 12 descends in the direction of gravity from an opening 11, which is located in the upper space of a refrigerant container 3 enclosing a superconducting coil 1 aud liquid helium 2. The part 12 penetrates the bottom wall of the refrigerant container 3. The part 12 is further extended to a vacuum heat insulating layer 4. The part 13 rises up in the direction against the gravity and penetrates the vacuum heat insulating layer 4 and the upper wall of a vacuum container 5. The pipe is arranged in a U shape as a whole. When the rising-up distance required for heat insulation is constant, the height of the upper wall of the vacuum container 5 can be lowered by the height of the refrigerant container 3. Thus the total height of the cryostat can be lowered.
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