M-shell X-ray production cross sections for PIXE applications

Abstract

M-shell X-ray production cross sections by protons of energies 0.1–4.0 MeV are reported for the most intense Mαβ(M4,5N6,7), Mγ(M3N4,5) and M3O4,5 M-X ray transitions appearing in PIXE spectra. The cross sections have been measured systematically for selected heavy elements between Ta and Th (Z2=73–90). Measured M-X-ray production cross sections were found to be universal with respect of M-shell scaled velocity ξM. The data are compared with available theoretical calculations of M-shell ionization by charged particles based on the plane-wave Born approximation (PWBA) and the semiclassical approximation (SCA), as well as the ECPSSR theory and relativistic RPWBA-BC which are going beyond the first order treatment. Simple parameterization of experimental proton induced M-X-ray cross sections is proposed for PIXE applications. This parameterization, being accurate within ±5%, can be used for precise determination of heavy metal concentrations by PIXE technique.