Differential Cross-Sections for One- and Two-Electron Capture by Highly Charged Ions (N 7+ , O 7+ , O 8+ , Ne 7+ , Ne 8+ ) at Low keV Energies

This letter reports the first measurements of differential cross-sections (DCS) for one- and two-electron capture by highly charged ions at low keV energies. These measurements have been achieved using a new type of spectrometer with a design based on a two-dimensional position-sensitive detector. A comparison of the shape of DCS for, respectively, one- and two-electron capture processes provides information about mechanisms for two-electron capture. Our results concerning capture by highly charged ions ( q = 7,8) clearly indicate that the two electrons are captured successively during the collision.