Electron source on the basis of field emitters with minimized jet-emittance growth

摘要

Electron gun (10) comprising:an emitter element (26), which is adapted to, an electron beam (28) to produce;an extraction electrode (20), the to the emitter element (26) is arranged adjacent to the electron beam (28) of this invention, to extract, wherein the extraction electrode (20), an opening (24) contains;a grid (32), which in the opening (24) is arranged to the field strength of an electrical field to a surface of the emitter element (26) to control and the homogeneity of the electrical field to the surface of the); and to improvea emittance compensation electrode (ece, 34) to the grid (32) adjacent to each other on the side of the grid (32) and the emitter element (26) is arranged opposite one another and which is adapted to a emittance growth of the electron beam (28), which is caused by the beam (28) of the grating (32), by matching of the electrical fields, which on both sides of the grid (32); and, to control aa controller (21, 54) that is configured,an extraction voltage to the extraction electrode (20) and the grating (32), in order to achieve a desired current density in the electron beam, and to produce a to the ece (34) to determine voltage to be applied, wherein the voltage corresponds to the extraction voltage, so that the emittance growth of the electron beam in the location and pulse-phase-space, which is caused by the beam (28) of the grating (32), is minimized;wherein, due to the to the ece (34) applied voltage, the electrical fields, which on both sides of the grid (32), are the same.