This paper reviews the development and present status of a novel gas dynamic RF-only funnel technique for low-energy ion beam extraction into vacuum. This simple and original technique allows for the production of high-quality continuous and pulsed ion beams in a wide range of masses, which have a very small transverse and longitudinal emittance.
Keywords: RF buncher; RF-only funnel; RFQ and SPIG beam cooler; buffer gas flow; gas dynamic and Monte Carlo ion-trajectory simulations.