Patent ID: 6797964
Filing Date: 2004-09-28
Classification: H01J

Abstract:
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<3.37Bâˆ’1(VA)Ã—10âˆ’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], wherein the magnetic field is configured to cause electrons produced by the plasma production vessel above an energy level to collide with the wall face.