| 摘要 |
PURPOSE:To control accurately the level of liquid helium regardless of the variation of pressure within a feed pipe of the liquid helium, by detecting the level of the liquid helium with a level sensor using a superconductor. CONSTITUTION:A fixed level of current is supplied to a liquid level sensor 11 from a current source 11. When the level of liquid helium changes, the resistance value of a superconductor constituting the sensor 11 is changed. A change of this resistance value is detected in the form of voltage. This output of detection is converted into a current by a voltage/current converter 12 and supplied to a controller 6. In such a way, it is possible to control accurately the level of liquid helium regardless of the variation of voltage in a feed pipe of the liquid helium. |
