| 摘要 |
PURPOSE:To assure uniform ion intensity by a method wherein a magnetic field generating means is composed so that the generated magnetic field may be stronger along the peripheral part than at the central part of a vacuum vessel. CONSTITUTION:A magnetic field generating means is composed so that the generated magnetic field may be stronger along the peripheral part than at the central part of a vacuum vessel 5. Permanent magnets 21a, 21b are arranged outside a plasma producing chamber 1 to generate stronger magnetic field along the peripheral part than at the central part of said chamber 1 (central part of vacuum vessel 5). Thus, the thick plasma that has been produced at the central part by electron cyclotron resonance is produced along the peripheral part of vessel 5 to be diffused onto the central part of vessel 5. Through these procedures, any matters accelerating the recoupling such as vessel wall, etc., in the central part of vessel 5 can be eliminated to make the plasma distribution uniform so that uniform ion beam intensity may be assured in all the parts of vessel 5.
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