K and L X-ray production cross sections and intensity ratios of rare-earth elements for proton impact in the energy range 20-25 MeV

The K alpha(1), K alpha(2), K beta(1), K beta(2), and the Ll, L alpha, L beta and L gamma X-ray production (XRP) cross sections and the relative intensity ratios for seven rare-earth elements with 60 less than or equal to Z less than or equal to 70 have been measured for 20, 22 and 25 MeV proton impact. The experimental data on the L-shell XRP cross sections for high energy proton impact have been reported for the first time. The measured XRP cross sections for all the K-lines and the relative intensity ratios K alpha(1)/K alpha, K alpha(2)/K alpha, K beta(1)/K alpha, K beta(2)/K alpha and K beta/K alpha: are in good agreement with the theoretical ones calculated using ECPSSR ionisation cross sections for all the elements investigated at the three beam energies. The Ll, L alpha, L beta, and L gamma XRP cross sections measured at the three proton energies are found to be in general higher than the theoretical values calculated using the ECPSSR ionisation cross sections and the RDHS model-based L-i sub-shell fluorescence and Coster-Kronig (CK) yields. The measured relative intensity ratios L beta/L alpha, and L gamma/L alpha exhibit good agreement with the theoretical ones for all the elements under investigation, whereas the Ll/L alpha ratios are found to deviate from the theoretical ones. (C) 2000 Elsevier Science B.V. All rights reserved.