| 摘要 |
PURPOSE:To control an exciting current by combining small freezers and a small superconductive magnet and reduce the size of the apparatus by a method wherein the superconductive magnet is housed in an internal tank filled with liquid helium and the 1st and the 2nd small freezers are directly attached to a heat retaining container in which the internal tank is contained. CONSTITUTION:A superconductive magnet 1 is housed in an internal tank 3 filled with liquid helium 2 and the 1st and the 2nd small freezers 20, 30 are directly attached to an external tank 5 of a heat retaining container 4. A freezing stage 24 of the freezer 20 is connected to a radiation shielding plate 6 and a helium recondensor 25 is provided immediately above the helium 2. The 1st and the 2nd freezing stages 34, 35 of the freezer 30 are inserted into the container 4 and a power lead 10, which supplies an exciting current to the superconductive magnet 1 is connected to the stage 35. The lead 10 is directly cooled by the stages 34, 35 and the shielding plate 6 is directly cooled with heat transmission by the stage 24 to control the exciting of current the magnet 1. |
