| 摘要 |
PURPOSE:To obtain an ion beam with little beam expansion, uniform energy density, and excellent quality by detecting a fluctuation superimposed on the arc current and automatically controlling the arc discharge condition in an arc chamber. CONSTITUTION:When an arc discharge occurs in an arc chamber 1 provided in the magnetic field due to a source magnet 8, a fluctuation DELTAi of a current noise component due to the plasma oscillation, etc. is superimposed on the current (i). The output voltage R(i+DELTAi) due to the arc current is extracted and the fluctuation can be extracted by feeding the arc current to the output of this arc power supply 2 through a resistor 3. This voltage R(i+DELTAi) is amplified by an amplifier 4 and zone-analyzed with predetermined (n) bandpass filters 5. The badpass filters 5 extract a specific fluctuation with a low frequency determined by ions, a zone-analyzed signal and the arc current (i) are fed to a control calculator 6, and a source magnet power supply 7 is controlled so as to have the energe specttrum for the usage purpose of the ion beam in advance. |
