| 摘要 |
PROBLEM TO BE SOLVED: To shorten the time until a superconducting coil is cooled to a prescribed temperature by a method where a helium tank provided with a gas exhaust vent, which is used when liquid helium in the interior of the tank is vaporized, is provided so that the outer surface of the tank and the coil conducts heat-exchange with each other by a solid heat transfer. SOLUTION: A helium tank 21 for housing a liquid helium is provided between a heat radiation shielding chamber 2 defined by a heat radiation shielding plate and an upper heat transfer plate 7. The plate 7 is provided, in such a way as to make a starting heat contact with the bottom of this tank 21 and a superconducting coil 3 wound on a coil spool 3a, so that the part between the bottom of this tank 21 and the coil 3 conducts solid heat transfer. Moreover, a gas exhaust vent 22 is provided in the upper part of the tank 21 via a conduit 22a. According to this constitution, since the coil 3 results in being cooled also by a heat exchange of the coil 3 with the low-temperature tank 21, the time from the start of the cooling of the coil 3 to reach the prescribed low temperature of the coil 3 can be shortened, in comparison with the case where a cooling heat source is only a refrigerator 4 for a cryogenic temperature. |
