| 摘要 |
PURPOSE:To carry out degassing treatment automatically without overloading a vacuum pump by turning on and off electric supply to heaters, which heat an electron-gun chamber, around a set vauum degree of the electron-gun chamber. CONSTITUTION:An electric-field discharging electron gun is constituted by installing a chip 2, the first anode 3 and the second anode 4 in an electron-gun chamber 1, and the chamber 1 is exhausted with a vacuum pump 5 driven with a pump electric-power source 10. The vacuum degree of the chamber 1, after being detected with a measuring circuit 11, is given to a control circuit 14. The chamber 1 is provided with an external heater 7 and an internal heater 6 which is attached to the first anode 3. An electric power source 13 used for the heaters 6 and 7, and the signals of temperature detectors 8 and 9 are connected to the control circuit 14. Owing to such constitution, degassing treatment can be automated by controlling the temperatures of the heaters 6 and 7 according to the vacuum degree while monitoring the vacuum degree by means of the control circuit 14. |
