K and L X-ray production cross sections and intensity ratios of rare-earthelements 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 be ta and L gamma X-ray production (XRP) cross sections and the relative inten sity ratios for seven rare-earth elements with 60 less than or equal to Z l ess than or equal to 70 have been measured for 20, 22 and 25 MeV proton imp act. The experimental data on the L-shell XRP cross sections for high energ y proton impact have been reported for the first time. The measured XRP cro ss 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 b eta/K alpha: are in good agreement with the theoretical ones calculated usi ng ECPSSR ionisation cross sections for all the elements investigated at th e three beam energies. The Ll, L alpha, L beta, and L gamma XRP cross secti ons measured at the three proton energies are found to be in general higher than the theoretical values calculated using the ECPSSR ionisation cross s ections and the RDHS model-based L-i sub-shell fluorescence and Coster-Kron ig (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 th e elements under investigation, whereas the Ll/L alpha ratios are found to deviate from the theoretical ones. (C) 2000 Elsevier Science B.V. All right s reserved.