| 摘要 |
PURPOSE:To facilitate the maintenance by supplying the gas to a plasma generating chamber mainly through an ion take-out electrode system. CONSTITUTION:A gas lead port 49 is provided in a gas chamber 46. Since the vacuum conductance of the take-out electrode system 48 is high, the gas pressure in a plasma generating chamber 41 is approximately equal to the gass pressure in the gas chamber 46, while the gas pressure in a vacuum exhaust chamber 51 is considerably lower than said gas pressures. Consequently the high voltage is produced in the plasma generating chamber 41 and when the gas chamber 46, gas lead port 49, the portion 50 having low vacuum conductance and the vacuum exhaust chamber 51 are near to the ground potential, the regulation and the control of the gas supply system can be facilitated. |
