Patent ID: 8944679
Filing Date: 2015-02-03
Classification: G01K,G01N

Abstract:
1. An electrode member comprising: a plurality of concentric spherical electrode parts having a spherical center point, each of the plurality of concentric spherical electrode parts having a radius, each of the plurality of spherical electrode parts being formed by a spherical plate, the radii being different from each other, and heating devices provided for the plurality of concentric spherical electrode parts, wherein each of the plurality of concentric spherical electrode parts are disposed in an insulated state and voltages are independently applied to each of the plurality of concentric spherical electrode parts, electron passage openings are configured to extract electrons moving from the spherical center point to an outside of each spherical electrode part, the electron passage openings being respectively formed at positions on each of the plurality of concentric spherical electrode parts crossing a plurality of straight lines radially extending from the spherical center point, and voltages are applied to each of the plurality of concentric spherical electrode parts, respectively, so that the electron passage openings function as electrostatic lenses that cause a trajectory of electrons passing through each of the electron passage openings to converge around a center of the opening.