Abstract: The device comprises an ionizing unit for the production of low-energy (100-1000 eV) ions (FIG. 2a) with a second negative medium voltage (-100 to -1000 V) grid (6') cathode (6), a second also grid (13') and low-voltage (0 to +100 V) anode (13) and a third medium voltage (-100 to -1000 V) accelerating cathode (12, 12'), to extract the ions from the unit of three grids (6', 13',12'). For the production of high-energy (from 10 to beyond 200 keV) ions (FIG. 3a) there are provided in succession starting from target (2): a first low-voltage (0 to +100 V) anode (7', 7"), a second low-voltage (0 to +50 V) grid (13.sup.