High energy PIXE: New experimental K-shell ionization cross sections for silver and gold and comparison with theoretical values from ECPSSR/RECPSSR models

Abstract

In high energy PIXE, a high energy ion beam, up to several tens of MeV, is used to analyze heavy elements in a thick sample. The knowledge of the interaction cross-section with the atoms is essential to perform quantitative analysis. As measured data in this range of energy are scarce, an experimental campaign was conducted at the C70 cyclotron of the GIP ARRONAX to measure the K-X-ray production cross-sections for silver and gold with proton energies 30, 42, 54 and 68 MeV. The detector efficiency, the beam intensity, and the target thickness were measured accurately to produce precise data. To convert the K-X-ray production cross-sections into the K-shell ionization cross-sections, an average value of the K-shell fluorescence yield, calculated from a compilation of existing data, was used. The outcomes of the campaign are in good agreement with the few existing data and the theoretical prediction of the RECPSSR model.