Electron beam unit i.e. electron emitter, for creation of expanded irradiation field of electrons for e.g. set of applications, has secondary element whose recess corresponds to size of aperture that exhibits larger diameter than recess

摘要

The unit has a heating cathode (900) for creation of electrons. A lattice arrangement comprises primary and secondary lattice elements (901, 902). A beam diaphragm (904) is provided with an aperture (905), where a beam finger (906) is formed in the aperture. An end of the diaphragm is formed as an electron exit window (907). The secondary element is formed as a beam field definition element and comprises an electron-impermeable outer region and an electron-transmissive recess (903). The recess corresponds to a form and a size of the aperture that exhibits a larger diameter than the recess. The beam diaphragm is designed as an anode of an electron accelerator. The primary and secondary lattice elements are designed as coarse-meshed lattice and a fine-meshed lattice, respectively. The electron exit window is designed as a continuous electron-transmissive electron exit window. An independent claim is also included for a method for creating an irradiation field using an electron beam unit.