K-shell x-ray production in 6C, 8O, 9F, 11Na, 12Mg, and 13Al by 0.5-8.0-MeV helium ions.

{ital K}-shell x-ray production cross sections are reported for incident {sup 4}He ions for elements with {ital K}-shell binding energies between 277 eV (C) and 1487 eV (Al). The data are compared with the first-order Born approximation (plane-wave Born approximation for direct ionization and Oppenheimer-Brinkman-Kramer approximation for electron capture) and to the energy loss and Coulomb deflection effects, perturbed stationary-state approximation with relativistic correction (ECPSSR) theory. The energy of the helium ions ranged from 0.5 to 6.0 MeV for He{sup +} and 6.5 to 8.0 MeV for He{sup 2+}. The targets used in these measurements were {sub 6}C, {sub 8}O, {sub 9}F, {sub 11}Na, {sub 12}Mg, and {sub 13}Al. Except for a systematic overprediction of the data at the lower projectile velocities, the ECPSSR theory is found to fit the data. The first-order Born theory is found to fit the data at higher energy, but greatly overpredicts the data at low energy.