K-shell ionization by low-energy 14N ions

Abstract

K-shell ionization by slow, heavy projectiles has been studied for moderately asymmetric ( Z 1/ Z 2 ∼ 0.3) collisions by measuring K-X-ray production cross sections in Ca, Sc, Ti, Cr, Fe and Cu excited by 14N ions of energy 1.75–3.15 MeV. The influence of multiple ionization in L- and M-shells on measured data was estimated by analyzing K-X-ray energy shifts and K β/K α intensity ratios. The results are compared with the predictions of K-shell ionization theories, based on the plane-wave Born approximation (PWBA), semiclassical approximation (SCA), binary-encounter approximation (BEA), and adiabatic molecular orbital (MO) approach. Different corrections to these approaches, to account for the higher-order effects, are discussed. The data are not satisfactorily described in detail by discussed theories over the whole energy range, but the SCA calculations reproduce the present, low-energy data quite reasonably. The need for a more realistic description of the electron binding effect is discussed.