The instant invention involves a system for generating high current density charged particle beams. The system includes a plurality of high intensity ion sources in combination with two charge exchange cells aligned linearly with one another. The ions are converted from one type of charge to an opposite charge in two stages. In the first stage, several beams of positive ions, for example, derived from a plurality of positive ion sources are beamed into a charge exchange cell and converted into neutrals. The several beams of neutrals from the first cell are then directed into a second charge exchange cell where the neutrals are converted into negative ions.