The Frankfurt RF-driven ion source

An RF-driven volume ion source based on the high efficiency ion source (HIE FS) has been developed at the Institut fur Angewandte Physik in Frankfurt. The RF-driven ion source operates at a frequency of 3.5 MHz with a maximum duty factor of 10%. Using an 11 kW RF-amplifier a He+-beam with a current o f 82 mA as well as an oxygen beam with a current of 39 mA and an O+-fractio n of 90% could be extracted. Experiments were done to study the operating c onditions of the ion source. For the working gases helium and oxygen the em ission current density in dependence on several ion source parameters was i nvestigated Furthermore, the energy distribution of the electrons and ions in the plasma as well as the beam composition for several working gases wer e studied. This article will give a detailed description of the ion source and the experimental setup. In addition, various dependencies between the p lasma parameters and the emission current density, the energy distribution of electrons and ions and the beam composition are presented. (C) 2000 Else vier Science B.V. All rights reserved.