Erika—A program for the decomposition of line spectra

Abstract

Effects of the atomic environment on the L1, L2, L3, M1, M2, M3, and N1 electron binding energies in samarium generated in the electron capture decay of radioactive 149Eu were investigated by means of the internal conversion electron spectroscopy using the conversion electron spectrum of the 22.5 keV M1 + E2 nuclear transition in the daughter 149Sm. In this investigation, four pairs of 149Eu sources prepared by vacuum evaporation deposition and by ion implantation at 30 keV with the use of four different source backing materials, namely polycrystalline carbon, aluminium, gadolinium and platinum foils, were employed. The greatest average difference of (3.1 ± 0.1) eV in the L1, L2, L3, and M1 subshell electron binding energies was observed between the 149Eu sources prepared by ion implantation into the aluminium and platinum substrates. On the other hand, minimal differences in the electron binding energies were generally found between samarium generated in the evaporated layer and in the bulk for the individual investigated source backings with the exception of the gadolinium foil. A doublet structure of all investigated conversion electron lines with the average values of 8.1 ± 0.2 eV and 1.5 ± 0.1 for the separation energy and the intensity ratio of the low-energy to high-energy components, respectively, was observed for the 149Eu sources prepared by ion implantation into the aluminium and carbon foils. This structure was presumably caused by the presence of both the trivalent and divalent Sm ions in the sources. No significant differences in natural widths of the L1, L2, L3, M1, M2, and M3 samarium atomic levels among the investigated matrices were observed with the exception of the source prepared by the implantation of the 149Eu ions into the platinum foil for which the determined values for all investigated subshells were apparently higher.