Removal of molecular contamination in low-energy RIBs by the isolation-dissociation-isolation method
Greiner, F., Dickel, T., Andrés, S. A. S., Bergmann, J., Constantin, P., Ebert, J., . . . Weick, H. (2020). Removal of molecular contamination in low-energy RIBs by the isolation-dissociation-isolation method. Nuclear Instruments and Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms, 463, 324-326. doi:10.1016/j.nimb.2019.04.072
Published inNuclear Instruments and Methods in Physics Research. Section B: Beam Interactions with Materials and Atoms
© 2019 The Authors
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 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.