Determination of mean energies and impact parameters characteristic of charge-changing reactions.

Measurements are reported of mean energies of argon recoil ions produced by beams of 23-MeV Cl[sup 5+,8+,10+] or 19-MeV F[sup 9+], and of neon recoil ions produced by beams of 22-MeV Cl[sup 4+], detected in coincidence with the charge-changed outgoing projectile. A screened-elastic-Coulomb-scattering calculation permits estimation of impact parameters characteristic of each pair ([ital q],[ital r]) of final projectile- ([ital q]) and recoil- ([ital r]) ion charge states. The results are found to be in good agreement with impact parameters deduced from measured cross sections and do not require measurement of projectile scattering angle.