Ion source and operation method thereof
AssigneeNissin Electric Co., Ltd.
InventorTakatoshi Yamashita
Life of this patent
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Abstract
This ion source is set up to satisfy a relation L<3.37B−1{square root}(VA)×10−6 where the arc voltage applied between a plasma production vessel 2 and a filament 8 is VA[V], the magnetic flux density of a magnetic field 19 within the plasma production vessel 2 is B[T], and the shortest distance from a most frequent electron emission point 9 located almost at the tip center of the filament 8 to a wall face of the plasma production vessel 2 is L[m].
Claims6
An ion source comprising:
- a plasma production vessel which serves as an anode;
- a filament provided on one side of said plasma production vessel;
- a reflector provided opposite said filament on the other side of said plasma production vessel and kept at a filament potential or a floating potential;
- and
- a magnet for generating a magnetic field in a direction of connecting said filament and said reflector within said plasma production vessel,
- wherein a relation
- L<3.37B−1{square root}(VA)×10−6
- is satisfied, where the arc voltage applied between said plasma production vessel and said filament is VA[V], the magnetic flux density of the magnetic field within said plasma production vessel is B[T], and the shortest distance from a most frequent electron emission point located almost at the tip center of said filament to a wall face of the plasma production vessel is L[m].
A method for operating an ion source which comprises a plasma production vessel serving as an anode, a filament provided on one side of said plasma production vessel, a reflector provided opposite said filament on the other side of said plasma production vessel and kept at a filament potential or a floating potential, and a magnet for generating a magnetic field in a direction of connecting said filament and said reflector within said plasma production vessel, the method comprising a step of leading out an ion beam with the following relation being satisfied,
- L<3.37B−1{square root}(VA)×10−6
- where an arc voltage applied between said plasma production vessel and said filament is VA[V], a magnetic flux density of the magnetic field within said plasma production vessel is B[T], and a shortest distance from a most frequent electron emission point located almost at the tip center of said filament to a wall face of said plasma production vessel is L[m].
Dependencies are inferred from the claim text.