| 摘要 |
<p>PURPOSE:To effectively perform ultra-high vacuum exhaust and obtain a great amount of stable field emission current by providing a means that always keeps higher anode temperature than ambient temperatures. CONSTITUTION:Electron gun chambers 1 and 11 are heated externally by a heating body 16 and an anode 6 is also heated by a heating body 8. The gas generated at heating is exhausted by vacuum pumps 14 and 15. To differentiate the time of heating an anode 8 with low heat capacity and the time of heating the chamber wall, timers 19 and 22 are provided in several heating power supplies 20 and 23. Suppose that the temperature of the anode 6 is T2 and the temperature of the electron gun chamber wall 4 is T1, the timers 19 and 22 are activated and controlled so that the temperature at cooling can always be set to T1<T2. As a result, the gas adsorption onto the surface of the anode 6 that must be kept in the most cleanest surface can be prevented.</p> |
