Properties of RFQ accelerators for ion implantation

While electrostatic accelerators are commonly used for ion implantation in research and industry, the progress in the development of efficient low energy rf accelerators has led to proposals for the application of radiofrequency quadrupoles (RFQ) structures in ion implanters. RFQs are rf structures which can efficiently accelerate ion beams to energies between 100 keV and several MeV. Features are a strong electrical rf-focusing which allows ion beam currents up to 10 mA and a compact and reliable system with the ion source only on a low 10-30 kV potential. Critical issues are the beam quality and the energy variation. The status of work on RFQ implanters in Frankfurt will be discussed. (orig.)