Formation of the charge distribution of fast multicharged ions passing through a carbon target

Abstract

The equilibrium and nonequilibrium charge distributions of ions with nuclear charges from 10 to 18 are analyzed by evaluating ion charge-exchange cross sections with the density effect taken into account. It is shown that the increase in the cross section for electron loss and the decrease in the cross section for electron capture by ions in a solid target (carbon) compared with gases is maximum in the region of 0.1–0.2MeV/nucleon. It is also shown that, in the case of a solid target, the energy by ion cross section for electron loss by an ion becomes maximum decreases, which is explained by a decrease in the binding energy of the active electron in the ion because of the presence of excited states. This leads to an increase in the average equilibrium ion charge in solid targets compared with the value in gases. The results of calculations agree with the experimental data in the entire considered energy region. The proposed method for calculating the ion charge-exchange cross sections in solid targets also makes it possible to qualitatively describe the dependence of the average ion charge on the target thickness and calculate the thickness (required to determine the equilibrium charge distribution) for different energies and charges of the ion nucleus.