Measurement of ionization, charge exchange and ion confinement times in charge breeder ECR ion sources with short pulse 1+ injection of metal ions
Luntinen, M., Angot, J., Tarvainen, O., Toivanen, V., Thuillier, T., & Koivisto, H. (2022). Measurement of ionization, charge exchange and ion confinement times in charge breeder ECR ion sources with short pulse 1+ injection of metal ions. In ICIS2021 : 19th International Conference on Ion Sources (Article 012009). IOP Publishing. Journal of Physics : Conference Series, 2244. https://doi.org/10.1088/1742-6596/2244/1/012009
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2022Copyright
© Authors, 2022
The Consecutive Transients (CT) method is used for estimating the characteristic times of ionization, charge exchange and confinement within the plasma of a Charge Breeder Electron Cyclotron Resonance Ion Source (CB-ECRIS). The method reveals differences in the characteristic times between different source configurations, with K9+ charge breeding efficiencies of 8.9 % and 20.4 %, and allows qualitative explanation of the improved breeding efficiency. The increase in K9+ efficiency is accompanied by a decrease in ionization time for low charge states, a decrease of charge exchange time for high charge states, and an overall decrease of the ion confinement time, which increases non-linearly with the charge state. The charge exchange time exhibits a minimum near charge state K8+, indicating low neutral density near the plasma core. The CT-method yields a distribution of possible ne and (Ee) corresponding to the spatial distribution of different charge state ions. The results hint at a non-uniform plasma electron density and energy distribution as well as a nested-layer distribution for the ion populations — hot and dense plasma with high charge state ions near the plasma core.
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