L X-ray production cross sections of 59<or=Z<or=70 elements by proton and⁴He ion impact

Abstract

L x-ray line production cross sections for proton and 'He ion bombardment of elements with atomic number Z ranging from 59 to 70 have been measured in the energy range 0.25-1.80 MeV far protons and 0.40-1.80 MeV far 4He ions. An overall good agreement with the few existing data has been observed. The linear dependence on Z of the logarithm of the cross sections has been confirmed also in this region. The agreement of the measured data with the predictions of a modified ECPSSR model, suggested by us and based on a recalculation of the binding correction (UA-ECPSSR), is generally good, except for the lowest incident energies.

L-subshell ionization cross sections of some rare-earth elements by impact of 2 MeV ions: dependence on atomic number

“…The linear dependence on Z of the logarithm of both theoretical and experimental ionization cross section values can be clearly pointed out. This observation agrees with other observations seen in the literature (Vigilante et al 1991).…”

“…In making the comparison between theory and experiment for the L 1 -subshell, the ECPSSR theory seems to overestimate the experimental values for all values of Z. This agrees somewhat with other observations seen in the literature (Hallak 1997a, b, Bogdanovic et al 1996, Sarkar et al 1995, Orlic 1994, De Cesare et al 1994, McNeir et al 1994, Semaniak et al 1993, Cai et al 1992, Sarkadi and Mukoyama 1991, Vigilante et al 1991 at the above-mentioned energy. For the L 2 -subshell, the data shown in figure 1 indicate the same exponential functional dependence for both theory and experiment, but the ECPSSR theory now underestimates the experiment.…”

“…For the L-shell, the situation is less favourable and large discrepancies have been observed between measured L-subshell ionization cross sections and predictions of the ECPSSR theory, especially at low energies. The situation for helium ion impact on different targets is much worse than that for protons and much larger discrepancies are observed for the ionization cross sections of individual subshells (Hallak 1997a, b, Bogdanovic et al 1996, Sarkar et al 1995, Orlic 1994, De Cesare et al 1994, McNeir et al 1994, Semaniak et al 1993, Cai et al 1992, Sarkadi and Mukoyama 1991, Vigilante et al 1991. Experimental L-subshell cross sections for different targets are normally normalized by the corresponding theoretical values and plotted against the reduced velocity parameter.…”

Investigation of relative intensities of L‐shell lines of some rare earth elements by impact of 2 MeV 4He2 ions

“…The theory seems to overestimate the experimental data for all elements examined. This result is in agreement with our previous work 1 -3 and that of Vigilante et al 12 for protons and 4 He ions, Mehta et al 21 for carbon ions and Bogdanovic et al 22 for 16 O ions. They all found that the logarithm of the crosssections or L-subshell intensity ratios varies linearly with the atomic number.…”

4He-induced L X-ray production cross sections in Pt and Bi

“…This disagreement came originally from an underestimation of the L b and L c X-ray production cross sections. The compilation of data on 4 He-induced X-ray emission is still incomplete as can be seen in [9][10][11]. L shell X-ray production cross sections are lacking for L a , L b and L c lines at energies above 1.8 MeV for Pt and Bi.…”