Electron Capture in M-Shell X-Ray Production from Heavy Elements by 25- and 35-MeV Fluorine Ions

M-shell x-ray production cross sections have been measured for thin solid targets (~2 ¿g/cm2) of Au, Pb, Bi, and U for 25 and 35 MeV incident 199Fq+ ions (q = 4, 5, 6, 8, 9). The target M-shell x-ray production cross sections by projectiles with one or two K-shell vacancies are found to be enhanced over those by projectiles without K-shell vacancies. The cross sections averaged over target thickness were measured as a function of target thicknesses. Electron capture (EC) to the L-, M-, ...shells and EC to the K-shell of the projectile, have been extracted from the data. These are compared with the predictions of first Born theories, i.e., OBK of Nikolaev for EC. The data are also compared with the theory by Brandt and Lapicki that goes beyond the first Born approximation, i.e., the ECPSSR approach which accounts for the Energy loss, Coulomb deflection and Relativistic effects in the Perturbed Stationary State theory.