Multiple ionization in 67Ho and 71Lu due to the impact of nitrogen- and silver-ions

Abstract

The energies of various L X-ray transitions namely Ll, Lα, Lη, Lβ1,4, Lβ3,6, Lβ2,15, Lβ5,7, Lβ9,10, Lγ5, Lγ1, Lγ2,3 and Lγ4 have been measured in 67Ho and 71Lu due to the impact of 5–11 MeV N3+,4+ - and 90–180 MeV Ag7+, 8+, 12+,14+- ions. The change in the energy values of various transitions from the standard values have been calculated from the changes in the positions of the centroids of various L X-ray peaks after fitting the L X-ray spectra of these elements using NFIT computer program. Since the energy shifts are caused due to the multiple ionization of the M-, N-, O- shells simultaneous to the L-shell ionization, the measured energy shift values have been compared to the corresponding single-hole values to calculate the number of spectator vacancies caused in the outer-shells simultaneous to inner-shell ionization. Only one M-spectator vacancy is estimated in both 67Ho and 71Lu elements due to N-ion impact while 5 −7 M spectator vacancies in 67Ho and 6–8 M spectator vacancies in 71Lu are estimated for Ag-ion impact. It is evident from the measured intensity ratios (higher than the single-hole values) for the transitions Lβ1(L2-M4)/Lγ1(L2-N4) and Lα(L3-M4,5)/Lβ2,15 (L3-N4,5) and lower than the single hole values for Lγ2,3(L1-N2,3)/Lγ4(L1-O2,3) that more vacancies are caused in the N-shell than in the M-shell and a lower degree of multiple ionization in the O-shell than in the N-shell. The number of spectator vacancies caused by Ag-ion impact has been found to be 5–7 for M- and 19–22 for N-shell in 67Ho and 6–8 M-shell and 12–22 for N-shell in 71Lu respectively.