Removal of molecular contamination in low-energy RIBs by the isolation-dissociation-isolation method

Florian Greiner, Timo Dickel, Samuel Ayet San Andrés, Julian Bergmann, Paul Constantin, Jens Ebert, Hans Geissel, Emma Haettner, Christine Hornung, Ivan Miskun, Wayne Lippert, Israel Mardor (+7 others)
2019 Nuclear Instruments and Methods in Physics Reseach B  
A B S T R A C T Experiments with low-energy rare ion beams often suffer from a large amount of molecular contaminant ions. We present the simple isolation-dissociation-isolation method to suppress this kind of contamination. The method can be applied to almost all types of low-energy beamlines. In a first step, a coarse isolation of the massto-charge ratio of interest is performed, e.g. by a dipole magnet. In a second step, the ions are dissociated. The last step is again a coarse isolation of
more » ... oarse isolation of the mass-to-charge ratio around the ion of interest. The method was tested at the FRS Ion Catcher at GSI with a radioactive ion source installed inside the cryogenic stopping cell as well as with relativistic ions delivered by the synchrotron SIS-18 and stopped in the cryogenic stopping cell. The isolation and dissociation, here collision-induced dissociation, have been implemented in a gas-filled RFQ beamline. A reduction of molecular contamination by more than 4 orders of magnitude was achieved. ⁎ Corresponding author at: afforganizationII. Physikalisches
doi:10.1016/j.nimb.2019.04.072 fatcat:tvkph2s3izaxrml64jhfwcl7ye