[en] The ion fractions, eta⁺, of 10 keV argon particles, scattered from a damaged copper surface, are measured with a time of flight spectrometer. The damage was introduced by bombardment with argon ions. The scattering angle was 30⁰. The results for different angles of incidence, psi, are reported. For psi < 10⁰ the ion fraction is relatively high (approx. 27% for psi = 4⁰) and decreases as psi increases. For psi = 15⁰ the value of eta⁺ is 7%, whereas for 21⁰ < psi < 27⁰ the value of eta⁺ appears to be constant (approx. 14%). An explanation is given by assuming interatomic ionization as well as neutralization processes along the trajectory of the scattered particles. The number of step-atoms, induced by ion bombardment, it estimated to be about 2 x 10¹⁴/cm². (orig.)