Projectile charge-state dependence of transfer ionization to single capture ratio in collisions of multiply charged ions with He

The ratios of the cross sections for the processes of transfer ionization (TI) and single capture (SC) were measured for 2 MeV/u ${\mathrm{Cl}}^{7+,9+,13+,14+,15+}$ and ${\mathrm{Ti}}^{15+,18+}$ projectile ions on He targets. The ratio was determined using a cold He gas target and measuring the coincidences between the projectile and the charge states of the emerging recoil ions. The measured ${\mathrm{\sigma }}_{\mathrm{TI}}$/${\mathrm{\sigma }}_{\mathrm{SC}}$ ratio shows a strong dependence with the projectile charge state that is well described by calculations based on the independent electron model. A model to take into account the effect of the electron screening of partially dressed projectiles in the target ionization is also presented.