| 摘要 |
PURPOSE:To prevent beam focusing-characteristic of several kinds of ion beam apparatuses from being deteriorated by making electrical field-distribution spread out along the incidence direction of ion beams similar to magnetic field- distribution spread out between the magnetic electrode plates of a magnetic deflection means. CONSTITUTION:Magnetic electrode plates 5a, 5b of a main electrostatic deflection means facing each other are fixed respectively to the side of the surfaces of insulating plates 9a, 9b facing each other arranged in parallel and also electrode plates 9a, 9b and 8a, 8b composing auxiliary electrostatic deflection means are fixed respectively to an ion beam incidence side and its emission side on the back of the insulation panels. An adequate D.C. voltage is supplied to them to change the electrical field at the end of the main electrostatic deflection means so that electrical field-distribution spread out along the incidence direction of ion means is made similar to magnetic field-distribution of a magnetic deflection means spread out in the same direction. Ion beams composed of kinds of ions selected by this, that is, external forces acting upon the selected beams are mostly cancelled at every positions located along the ion beam incidence direction, so that rectilinearity can be improved.
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