A source for generating ionizing radiation and in particular x-rays, to an assembly includes a plurality of sources and to a process for producing the source. The source comprises: a vacuum chamber; a cathode that is able to emit an electron beam into the chamber; an anode that receives the electron beam and that comprises a target that is able to generate ionizing radiation from the energy received from the electron beam; an electrode that is placed in the vicinity of the cathode and that allows the electron beam to be focused; a stopper ensuring the seal tightness of the vacuum chamber; and a mechanical part that is made of dielectric and that forms a portion of the vacuum chamber; and the stopper is fastened to the mechanical part by means of a conductive brazing film that is used to electrically connect the electrode.