Alpha-Decay Properties of Some Erbium Isotopes near the 82-Neutron Closed Shell

Abstract

New alpha-emitting isotopes of erbium, lying near the 82-neutron closed shell, were produced by ${\mathrm{Nd}}^{142}$+${\mathrm{O}}^{16}$ bombardments at incident energies up to 151 MeV. The nuclides studied and their alpha-decay properties are Alpha decay from erbium isotopes with $A<152$ was not observed, indicating that the alpha-particle binding energies of these isotopes are considerably higher than those for the 84-, 85-, and 86-neutron isotopes. Alpha reduced widths, calculated from the results for ${\mathrm{Er}}^{152}$ and ${\mathrm{Er}}^{153}$, were found to be higher than the corresponding dysprosium, holmium, and terbium isotopes. Relative excitation functions were obtained for some ${\mathrm{Nd}}^{142}({\mathrm{O}}^{16}, xn)$ and ${\mathrm{Nd}}^{142}({\mathrm{O}}^{16}, pxn)$ reactions.