First ion pulses out of a laser ion source trap

Resonance ionization laser ion sources (RILIS) are applied for the production of exotic ion beams with high isotopic and isobaric purity [1], limited only by surface ionization of unwanted atomic species. A new type of resonance ionization laser ion source is presently being deve-loped and tested at the RISIKO mass separator at Mainz University [2] for future use at on-line radioactive ion beam facilities. For highest isobaric selectivity, this RILIS approach [3] decouples the evaporation and ionization region by a combination of atomizer ion repeller ion cooler and trap, which is operated together with a titanium:sapphire (Ti:Sa) laser system [4]. The central part of this laser ion source trap (LIST) approach is a segmented and gas-filled radio-frequency quadrupole (RFQ) structure. A cross section through the atom source-repeller-trap combination is shown in Figure 1 togther with a typical potential distribution applied for trapping.