| 摘要 |
PURPOSE:To obtain a superconducting magnet which can reduce the liquid helium consumption and, at the same time, can simplify the device constitution. CONSTITUTION:The first and second heat stages 10 and 11 of a refrigerating machine 20 are thermally connected respectively to a first and second heat shields 6 and 7 provided between a helium tank 2 housing a superconducting coil 1 and vacuum tank 5. The machine 20 uses a magnetic coldness storing material so that the second heat stage 11 can reach the liquefaction temperature of helium. In addition, a pressure sensor 22 is provided to the tank 2 so as to detect the pressure in the tank 2 and a heater 21 is installed to the stage 11. A controller unit 23 controls the turning on/off of power supply to the heater 21 based on the output of the sensor 22 so that the pressure in the tank 2 cannot become negative. |
