Electrostatic lens, parallel beam generator and parallel beam converging device using the lens and collimator

摘要

Provided is a compact device which captures, over a large solid angle range, electrically charged particles emitted from a point source and parallelizes the trajectories of said charged particles. The present invention is configured from: an electrostatic lens comprising a plurality of axisymmetric electrodes (10-14) and an axisymmetric aspherical mesh (2) which has a surface that is concave away from the point source; and a flat collimator plate (3) positioned coaxially with the electrostatic lens. The acceptance angle for the electrically charged particles generated from a point source (7) is ±30° or greater. The shape of the aspherical mesh (2), and the potentials and the positions of a ground electrode (10) and application electrodes (11-15) are adjusted so that the trajectories of the electrically charged particles are substantially parallelized by the electrostatic lens. The electrostatic lens and the flat collimator plate are positioned on a common axis so that after the trajectories of the electrically charged particles have been substantially parallelized with respect to the axis, the charged particles enter the flat collimator plate (3) at an angle of incidence substantially perpendicular thereto.