Nuclear Spectroscopy of Neutron-Deficient Rare Earths (Tb through Hf)

Abstract

A survey has been made of electron-capturing nuclides produced by irradiating rare earths (Gd through Hf) of various isotopic enrichments with 22-Mev protons. Ion-exchange chemistry was performed, conversion-electron spectra were analyzed, and the various activities were cataloged. At least ten new activities, ${\mathrm{Tb}}^{153}$, ${\mathrm{Tb}}^{155}$, ${\mathrm{Tb}}^{156m}$, ${\mathrm{Dy}}^{155}$, ${\mathrm{Ho}}^{156}$, ${\mathrm{Ho}}^{160m}$, ${\mathrm{Ho}}^{162}$, ${\mathrm{Er}}^{168m}$, ${\mathrm{Yb}}^{171m}$, and ${\mathrm{Lu}}^{169}$ were found and studied. Eighteen previously known activities also were examined. Multipolarities consistent with the observed conversion electron intensity ratios are proposed. The positions of levels of even-even nuclei as a function of both proton and neutron number are discussed.