EBIS test ion source for HITRAP and charge breeding

The electron beam ion source MAXEBIS from Frankfurt University has been installed in a test beam setup at GSI to deliver highly charged ions for HITRAP [1] and to serve for charge state breeding experiments. Two ion sources dedicated to the production of singly charged ions for external ion injection have been connected to a so-called multi passage spectrometer (MPS), which is an integral part of the beam line. Recent experiments were dedicated to evaluate the parameters of the ion beam line, i.e. emittance, dependence of the charge state distribution on the confinement time in the electron beam, efficiency of external ion injection and the resolution of the multi passage spectrometer (MPS). Simulations of the beam-line using SIMION 7.0 were performed and additional elements were installed in order to improve the beam parameters for more efficient ion transfer. To simplify downstream focusing the setup has been equipped with new diagnostics and beam optics devices. Investigations of different modes of the ion transmission trough the MPS resulted in better resolution of the analyzing magnet. Figure 1 shows a typical TOF spectrum of charge bred argon ions injected from the sputter gun (solid line) and the rest gas ions without injections (dash line). Clear peaks of charge states of Argon from 12+ to 9+ appear and the rest gas peaks drop down being kicked away by more heavy Argon ions via the cooling process. The amount of charges due to Argon ions as compared to the amount of residual gas ions was estimated to be 10%. The breeding efficiency of the charge state 10+, as derived from the spectra, is 15%, so 10 Argon ions have been captured and charge bred.