L-SUBSHELL IONIZATION OF HEAVY-ELEMENTS BY CARBON AND NITROGEN-IONS OF ENERGY 0.4-1.8 MEV AMU/

L-shell x-ray production and subshell ionization cross sections have b een measured for 0.4-1.8-MeV/amu carbon and nitrogen ions for selected heavy elements with 72 less than or equal to Z(2) less than or equal to 90. The results are compared with the predictions of the ECPSSR the ory [perturbed-stationary-state (PSS) theory with energy-loss (E), Cou lomb deflection (C), and relativistic (R) corrections] describing both direct ionization and electron-capture processes and the semiclassica l approximation (SCA) calculations for direct ionization. For both the ories significant deviations are found for L(2)-subshell ionization in the low-energy range. The multiple ionization of outer shells was stu died by comparing L x-ray intensity ratios measured for heavy ions and protons. The ionization probabilities of the N-4 subshell at zero imp act parameter was extracted from these data. Measured ionization proba bilities are compared with the predictions of the SCA theory and the ' 'geometrical model.'' The influence of multiple ionization on the meas ured L-subshell cross sections is discussed.