Abstract: The invention provides an electron impact ion source for the generation of multiply- or super-highly-chared ions including an electron gun with cathode and anode for the creation and acceleration of electrons, a device for the axial-symmetric focussing of the electron beam, a device for introducing ionisable substances into an ion trap, which may be opened and closed, in the region of the axial-symmetric focussed electron beam, a device for destroying the electrons after they have passed the ion trap, and a device for creating a vacuum around the axial-symmetrically focussed electron beam and the ion trap within said beam. The device for the axial-symmetric focussing of the electron beam comprises at least two ring structures radially magnetized in opposing directions and each of these ring structures enclosed the electron beam.