K X-ray production by 3-4 MeV proton impact on selected lanthanoids

Measurements of K-shell X-ray production cross sections induced by proton beams with energies between 3 MeV and 4 MeV are presented. The studied elements were Ce, Nd, Gd, Dy, and Ho, as thick targets. The measured cross sections are evaluated through comparisons with the ECPSSR model, the eECPSShsR-UA theory, the adiabatic perturbation (also known as direct molecular orbital, or MO) theory, and the empirical fits of Kahoul et al. using a scaling based on the reduced velocity parameter xi(R)(K) in every case. Consideration is given to multiple ionization effects and electron capture contribution to K-shell ionization. It is shown that the experimental results are in good agreement with the theoretical predictions in the whole measured xi(R)(K) range. (C) 2010 Elsevier Ltd. All rights reserved.