| 摘要 |
<p>PURPOSE:To restrain generation of an ion by short-circuiting accelerating and focusing electrodes or supplying a negative potential to the accelerating and focusing electrodes at the time of initial adjustment. CONSTITUTION:Switches 201a, 201b, 201c separates electrodes 4, 5, 6 from power sources 10, 11, 12, respectively, at the time of initial adjustment, to thus short- circuit them to an electrode 3. When the switches 201a-201c are set at the time of the initial adjustment as shown in the Figure, an electron beam 2 emitted from an electron source is adsorbed by the electrode on the way without being accelerated forward. Accordingly, activation at the surface of a cathode can be realized without generation of an ion. After activation at the surface of the cathode, the switches 201a-201c are switched so as to apply a regular potential to the accelerating and focusing electrodes 4, 5, 6 from the power sources 10, 11, 12, to thus return them to the normal operation.</p> |
