Patent ID: 6717155
Filing Date: 2004-04-06
Classification: H01J

Abstract:
An electron impact ion source for the generation of multiply- or superhighly-charged ions, comprising:an electron gun with cathode and anode for the creation and acceleration of electrons, a device for the axial-symmetric focusing of the electron beam, means for introducing ionizable substances into an ion trap, which may be opened and closed, in the region of the axial-symmetric focussed focused 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 focused electron beam and the ion trap within said beam, the device for the axial-symmetric focusing 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, each two ring structures radially magnetized in opposing directions being connected by magnetic conductors to form a unified magnet system, whereby the closing magnetic field passes the ion residence zone in the ion trap, the cathode having a very high emissivity of &gE;25 A/cm2 with a small cathode diameter, and a vacuum device applying a vacuum of from 10âˆ’7 to 10âˆ’11 Torr in the ion residence zone while the electron impact ion source operates.