Patent ID: 6864486

Claim:
An ion source comprising an enclosure ( 1 ) with a closed loop exit hole for ion emission, an anode ( 3 ) arranged inside enclosure ( 1 ) opposite to the exit hole, a gas distributor communicated with the cavity of enclosure ( 1 ), a cathode, with enclosure ( 1 ) serving at least a part of the cathode, and a magnetic system composed of at least one magnetomotive force source made in the form of a permanent magnet ( 5 or 6 ) and arranged on the outside of enclosure ( 1 ) along the edge of the closed loop exit hole, with an end wall ( 2 ) of enclosure ( 1 ) being provided with the closed loop exit hole and manufactured of magnetically permeable material, the parts of said end wall separated by the closed loop exit hole serving as pole pieces ( 7 , 8 ) of the magnetic system and defining the first pole gap, with the magnetic system comprising pole pieces ( 9 , 10 ) defining the second pole gap formed as a closed loop exit hole and arranged opposite the first pole gap in the direction of ion emission, and the magnetomotive force source being located in space between the pole pieces of the first and second pole gaps, wherein the ratio of width of each pole gap and distance between the pole pieces of the first and second magnetic gaps in the direction of ion emission is not less than 0.05, with end wall ( 2 ) of enclosure ( 1 ) at the side opposite to the exit hole being manufactured of magnetically permeable material and defining in conjunction with pole pieces of the first and second pole gaps an open magnetic circuit.