| 摘要 |
PROBLEM TO BE SOLVED: To uniformize a beam current of an ion beam in a short time by an automatic control. SOLUTION: A plurality of beam current measuring instruments 16 is divided into a plurality of groups. Current amount flowing into respective filaments 3 is arbitrarily made to be varied, and current variation amount of each group at that time is obtained respectively, and the current flowing into each filament 3 is controlled based on each variation amount so that the current amount of each group approaches a preset value. COPYRIGHT: (C)2009,JPO&INPIT
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