K-shell x-ray production cross sections are reported for incident ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ ions for elements with 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 ${\mathrm{He}}^{+}$ and 6.5 to 8.0 MeV for ${\mathrm{He}}^{2+}$. The targets used in these measurements were ${}_6{}^{}{}_{}{}^{}\mathrm{C}$,${\mathrm{}}_8$O, ${}_9{}^{}{}_{}{}^{}\mathrm{F}$, ${}_{11}{}^{}{}_{}{}^{}\mathrm{Na}$, ${}_{12}{}^{}{}_{}{}^{}\mathrm{Mg}$, and ${}_{13}{}^{}{}_{}{}^{}\mathrm{Al}$. 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.

• Received 5 June 1991

DOI:https://doi.org/10.1103/PhysRevA.44.7252