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Abstract We show the effects of ladder ionization and hyperfine quenching on charge state distributions and spectral features of ions in electron beam ion trap (EBIT) devices. Ladder ionization with intermediate excitation of metastable states proceeds at lower than ionization potential electron beam energies, while hyperfine quenching reduces the lifetimes of these states by enhancing particular decay channels through nuclear-electronic coupling. Using Ni-like Pr and Nd ions, we show that these processes significantly alter ion populations and spectra, emphasizing the importance of incorporating hyperfine level specific modeling in EBIT studies. 

Abstract Charge-exchange recombination with neutral atoms significantly influences the ionization balance in electron beam ion traps (EBIT) because its cross section is relatively large compared to cross sections of electron collision induced processes. Modeling the highly charged ion cloud requires the estimate of operating parameters, such as electron beam energy and density, the density of neutral atoms, and the relative velocities of collision partners. Uncertainty in the charge-exchange cross section can dominate the overall uncertainty in EBIT experiments, especially when it compounds with the uncertainties of experimental parameters that are difficult to determine. We present measured and simulated spectra of few-electron Fe ions, where we used a single charge-exchange factor to reduce the number of free parameters in the model. The deduction of the charge-exchange factor from the ratio of Li-like and He-like features allows for predicting the intensity of H-like lines in the spectra.