Patent ID: 7800012

Claim:
Electron gun comprising: a sealed chamber, designed to be under a vacuum, a cathode placed inside the chamber and which comprises an emitting face, capable of emitting electrons, an anode forming a sealed window, formed facing this emitting face in one of the walls of the chamber, and capable of allowing electrons emitted by this emitting face to pass through, and biasing means to set up a voltage between the anode and the cathode, capable of accelerating these electrons towards the anode, the electrons thus accelerated forming a beam that passes through the anode, this electron gun being characterised in that the anode and the emitting face each have a curvature, the curvature of the anode making it capable of resisting a pressure difference between the inside and the outside of the chamber and the curvature of the anode being designed to cooperate with the curvature of the emitting face to focus the electron beam outside the chamber.