Transmission and charge state distribution of carbon ions emerging from nitrogen gas target in a tandem accelerator: Impact of stripper gas pressure

Abstract

In a tandem accelerator the knowledge of distribution of charge states as well as the overall transmission of incident ions is of great importance for optimized use of the accelerator. We have studied the effect of the stripper gas pressure on the charge state distribution and the transmission of incident carbon ions (^{12}C^{1-}) stripped in N_{2} gas target in a tandem accelerator in the energy range of 0.2–1.7 MeV. The observed charge state fractions of the outgoing beam show transition from nonequilibrium to equilibrium distribution as the stripper gas pressure is varied. The experimentally measured average charge values at different stripper gas pressures are compared with an empirical model for the equilibrium average charge. Apart from the charge state distribution, the stripper gas pressure is found to have a more interesting effect in the transmission of incident carbon ions (^{12}C^{1-}), which displays a maximum with pressure in the nonequilibrium region. The observed transmission behavior is explained qualitatively.