扇形分析磁場における三次近似大電流イオン軌道

概要

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In the preceding paper, we described the geometrical aberrations in a 3rd-order approximation for the sector type magnetic analyzer with pole pieces of linear boundaries and of parallel flat faces taking account of both effects of the fringing field and of the tilt of central ray to the virtual field boundaries. As further development of the study, trajectories of large current ion beam are derived analytically in a 3rd-order approximation under consideration of the effective space charge which is affected by neutralization due to secondary electrons. To express simply the effect of space charge, a new factor "index of space chage: κ" is introduced which is common in sector type magnetic analyzers. The attenuation of beam intensity and the influence of abundance ratio are also taken into account. The formulae of ion trajectory are programmed in MALT (Magnetic Analyzer with Linear Terminations), which can give ion trajectories and their coefficients individually in the field-free spaces of ion source side and of image side, and in the deflection space.As examples of calculation of these formulae some maps are presented which show clearly the effect of space charge on ion trajectories.
日本質量分析学会の論文