Systematic study of 4He ion-induced L-shell ionization for 46 ⩽ Z ⩽ 70 elements

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

“…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.…”

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

“…According to Vigilante et al [18], De Cesare et al [19] and Lapicki et al [20] the observed differences for L b and L c could be resolved by using more realistic wave functions for ions and atomic electrons, by taking into account intrashell transition processes, by studying binding energy effects in the framework of the united atom approximation and by a correction for quantum Coulomb deflection [8].…”

ion-induced L x-ray emission cross sections of ytterbium

“…It is also known that the use of 4 He 2+ ion beam results in a reduced background in PIXE spectra with lower minimum detection limits. However, the available data on ionization cross sections by 4 He 2+ ions is not sufficient to make a good judgement about the disagreements observed at low bombardment energies by several workers (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.…”