Charge state distribution and its equilibration of 2 MeV/u sulfur ions passing through carbon foils

Charge state distributions of 2.0 MeV/u sulfur ions of various initial charge states (6, 10, 11, 13+) after passing through 0.9, 1.5, 2.0, 3.0, 4.7, 6.9 and 10 μg/cm2 carbon foils have been studied. It is observed that the processes involving the L-shell electrons are equilibrated within the target thickness of ∼5 μg/cm2 and the charge equilibration over this thickness is ruled by the K-shell processes. Measured charge state distributions do not flat off to establish equilibrium within the measured thicknesses, but the mean charge states almost saturate to 12.4 for all initial charge states examined. Calculation with ETACHA code, developed by Rozet et al. [Nucl. Instr. and Meth. B 107 (1996) 67], is employed, although the present impact energy is lower than the assumed region for the code.