Patent ID: 8461548

Claim:
An ion beam irradiation device irradiating an ion beam to a target comprising: an ion source producing an ion beam including positive ions; one or more magnets provided between the ion source and the target for deflecting, converging or diverging the ion beam generated from the ion source to be irradiated to the target; and one or more electron sources producing electrons, wherein the one or more electron sources are located in a magnetic field gradient region formed on an ion beam upstream side and/or ion beam downstream side of the magnets and located outside a region passed by the ion beam, the magnetic field gradient region is formed within the range of a normalized position from 0 to 2, the normalized position is calculated by dividing a distance from the one or more magnets by an inter-pole gap of the magnets, and wherein an electron emitting direction of each of the one or more electron sources is oriented to supply the electrons to the magnetic field gradient region.