Stripping of fast heavy low-charged ions in gaseous targets

Abstract

Projectile-ionization (stripping) cross-sections and beam lifetimes have been calculated for heavy low-charged ions of Pb, Bi and U colliding with H, He, Be, Li, F, N, Ar and Xe atoms in the E=1–100 MeV/u energy range. Calculations have been performed for single-electron processes in the Born approximation using the LOSS computer code accounting for the atomic structure of the target. Results are compared with available experimental data, CTMC calculations and Z 2+ Z scaling where Z is the nuclear charge of the target atom. In the case of Pb-like ions (Pb 0+,Bi 1+,…,U 10+), the scaling law for the stripping cross-sections on the projectile charge and the target nuclear charge is obtained. In the energy range considered, the calculated cross-sections are proportional to Z 1.4 due to the screening of the target nucleus by its electrons which differs markedly from the Z 2-dependence given by the first-order perturbation theory. The role of multi-electron processes is briefly discussed.