Electron beam source, electron-optical apparatus comprising an electron beam source and method of operating an electron beam source

摘要

it is a elektronenstrahlquelle (1) is proposed, which quelloberflu00e4che (5) by means of a photonenstrahls (29) is illuminated, whose intensity is variable. the photonenstrahl supports the emission of electrons from the quelloberflu00e4che by a photoelectric effect. in addition, there is still a extraktionsfeld provided for electrons from the quelloberflu00e4che trigger.may also have a heizeinrichtung (7), the emission of electrons from the quelloberflu00e4che thermally to support. a elektronenstrahlstrom (1) is measured and the intensity of the photonenquelle (27) in dependence on the measured elektronenstrahlstrom set.