Dependence of binary electron production on the recoil ion charge state

We report the dependence of the production of binary encounter electrons on the charge state of recoil ions for 2.4 MeV/u Xe21+ on He and Ar. Doubly differential cross sections of electron emission are calculated with the nCTMC method. Double ionization dominates over single ionization near the binary encounter region for the He target. However, unexpected local enhancement of single ionization in the region has been observed. This enhancement is found to be related to the sequential removal of the two electrons. We find that the contributions to the cross section from various recoil ion charge states reach a maximum near Ar5+ for the Ar target. Total cross sections including all possible charge states of recoil ions are compared with experimental data