Abstract: A helium cooling apparatus according to the present invention comprises a refrigerator for cooling a refrigerant. The refrigerator is connected with the proximal end of a transfer line, which is used to transport the refrigerant. A port with a predetermined diameter is formed in a liquid-helium container which contains liquid helium. A condensation-heat exchanger, which is connected to the distal end of the transfer line, is inserted into the liquid-helium container through the port. A heat-transfer surface of the heat exchanger is formed with a plurality of grooves extending in the gravitational direction. The refrigerant is evaporated in the heat exchanger, and condensed liquid helium, adhering to the heat-transfer surface, drops along the grooves when helium gas in the liquid-helium container is cooled to be recondensed. Accordingly, the heat-transfer surface cannot be covered with the condensed liquid helium, so that a wide heat-transfer area can be secured.

Abstract: A magnetic refrigerating apparatus comprises a working substance adapted to produce heat when magnetized, and cool down when demagnetized, a superconductive coil for applying a predetermined magnetic field to the working substance, a regenerating pipe having a high-temperature portion and a low-temperature portion and being movable between a first position, where the high-temperature portion is located far away from the coil, and the low-temperature portion is located close to the coil, and a second position where the high-temperature portion is located close to the coil, and the low-temperature portion is located inside a vessel. The working substance and the regenerating pipe are respectively, so moved that the regenerating pipe is in the second position when the working substance is in the magnetization position, and that the regenerating pipe is in the first position when the working substance is in the demagnetization position.