| 摘要 |
PURPOSE:To prevent the heating of a cathode caused by ion bombardment and stabilize cathode temperature by insulating the section between a metal cylindrical electrode that supports an output window and a collector and applying a negative bias to the collector of this metal cylindrical electrode. CONSTITUTION:In an electron gun assembly body 2 an electron gun electrode 11 containing an annular cathode 9, and a heater 10, and an annular anode 12 are assembled together coaxially with a tube axis 8. Besides, the section between a metal cylindrical electrode 6 that supports an output window 5 and a collector 4 is insulated and for example, -300V is applied to the metal cylindrical electrode. Thus, for the potential distribution on the tube axix, low potential can occur on top of the collector 4. Therefore, the ion ionized inside the collector 4 is sucked out from the metal cylindrical electrode 6. As a result, the ion bombardment of the electron gun electrode 11 can be prevented and the cathode temperature can be stabilized. |
