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

Abstract

Measured L x-ray ionization cross sections for 4 He 2+ bombardment of Yb in the energy range 1.0-8.5 MeV are compared with the ECPSSR theory. Significant discrepancies between theory and experiment are observed at an incident beam energy below about 5 MeV. The discrepancies are greatly reduced by the inclusion of collision-induced intrashell coupling (ECPSSR-IS) and modifications of the binding factor in the theory in the united atom picture (ECPSSR-IS-UA). More specifically, in this case of Yb L-shell ionization by energetic 4 He 2+ ions, the contribution of L-subshell coupling towards better agreement with the theory is more significant than binding energy correction.

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

“…The experimental procedure is similar to that described in previous work (Hallak 1998). A beam of 4 He 2+ ions of 2 MeV was allowed to impinge onto thin MicroMatter targets of the fluorides of Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu with nominal thicknesses of 36.4-50.3 µg cm −2 .…”

“…L x-rays resulting from the beam particle-target interaction were analysed with the PIXANPC code (Clayton 1986) using the procedure discussed in detail in a previous publication (Hallak 1998). In short, the code was used in the 'individual-shell' mode to fit line groups belonging to each L-subshell independently.…”