Multiple K- and L-shell ionizations of target atoms by collisions with high-energy heavy ions

The inner-shell ionization processes of atoms by bombardment of fast heavy ions are studied systematically through high-resolution measurements of K x rays. The K-alpha satellite and K-alpha hypersatellite x rays from target K-shell ionization were measured for He, C, N, O, and Ar-ion impact at energies between 0.56 and 92 MeV/u for satellite x rays and between 4.7 and 92 MeV/u for hypersatellite x rays. From the intensity distribution of the K-alpha satellite x rays with a different number of L-shell vacancies, the L-shell ionization probability at small impact parameters (close collisions) have been obtained and the results are discussed in the framework of simple first-order theories like binary-encounter approximation (BEA), and semiclassical approximation (SCA). The results qualitatively agree with the BEA and SCA scalings at higher collision velocities than the orbital velocity of the L electrons. The intensity ratio between K-alpha hypersatellite x rays and K-alpha satellite x rays has been compared with results calculated by BEA and SCA. (C) 1999 Elsevier Science B.V.