Saturation effect in projectile- and target- x-ray production in collisions between 2.5 MeV/u highly charged Cu ions and gaseous targets

Abstract

L x-ray production cross sections have been measured for highly charged 2.5 MeV/u Cuq+ (q = 20–26) ions colliding with H2, Ne, Ar, Kr and Xe target atoms. The observed Cu L x-rays are due to the excitation and electron-transfer processes. The charge state dependence of the projectile L x-rays has been studied with Ar and Kr targets. We have derived the subshell resolved K-L1, K-L2 and K-L3 electron-transfer cross sections from the measured Ar K x-ray yields as a function of L vacancies in Cu ion. The measured projectile L x-ray production cross sections arising from the excitation and electron capture are found to saturate as target atomic number Zt increases. Similarly, a saturation has also been found in the Ar K-shell ionization cross sections as a function of Zp.