M-shell electron capture and direct ionization of gold by 25-MeV carbon and 32-MeV oxygen ions

M-shell X-ray production cross sections have been measured for thin solid targets of Au for 25 MeV612Csup(q+) (q=4, 5, 6) and for 32 MeV 816Osup(q+) (q=5, 7, 8). The microscopic cross sections were determined from measurements made with targets ranging in thickness from 0.5 to 100 μg/cm2. For projectiles with one or two K-shell vacancies, the target M-shell X-ray production cross-sections are found to be enhanced over those by projectiles without a K-shell vacancy. The sum of direct ionization to the continuum (DI) and electron capture (EC) to the L, M, N... shells and EC to the K-shell of the projectile have been extracted from the data. The results are compared with the predictions of first Born theories, i.e. PWBA for DI and OBK of Nikolaev for EC and the ECPSSR approach that accounts for energy loss, Coulomb deflection and relativistic effects in the perturbed stationary state theory. (orig.)