Charge Equilibration of High-Velocity Ions in Matter

Abstract

Publisher Summary This chapter describes the charge equilibration of high-velocity ions in matter. Charge state distributions of ions penetrating through matter can be calculated from electron capture and loss cross sections. The ion loses one or more electrons because of the Coulomb excitation into the continuum, leaving the ion in either a ground state or an excited state, depending on whether outer- or inner-shell electrons are lost, respectively. The mathematical description of charge-state fractions under nonequilibrium and equilibrium conditions is presented. Gaseous targets are used in the differentially pumped mode, as any foil window would obscure the charge state distributions to be measured. It is observed that when outer shells with low binding energies are involved, as is the case for very light and any slow projectile, transitions fall into or near the visible range then well-developed techniques of beam-foil spectroscopy can be applied to provide information on projectile excitation inside a gas or just outside a solid foil target.