| 摘要 |
PURPOSE:To remove a neutral particle beam by compositely mounting an energy separator and a neutral particle removing device consisting of two sets of special form lenses and two sets of diaphragms arranged so that convergence directions may mutually be rectangular between a condenser lens and an object lens. CONSTITUTION:A beam coming through a special form lens 10 passes through a diaphragm 11; the beam on a special form lens 12 deviating from an optical axis is energy-separated by the special form lens for being guided to a diaphragm 5. When only the special form lens 12 is operated and the special form lens 10 is not operated, a linear conversion characteristic vertical to the paper surface is obtained on the diaphragm 5 and the special form lens 12 has no conversion characteristic vertical to the paper surface. An ion beam 8 passed through the diaphragm 5 is focused on a target 7 by an axially symmetrical static lens 6. An optical system lower than the diaphragm 5 axially comes off the upper optical systems and a neutral particle beam 9 is interrupted by the diaphragm 5 without reaching a target 7. Thereby, neutral particles contained inside the beam can be removed.
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