High-spin structure of 139Eu.

Abstract

The $_{\mathrm{}63}^{139}\mathrm{Eu}_{76}$ nucleus has been investigated by \ensuremath{\gamma}-\ensuremath{\gamma} coincidence measurements employing the $^{92}\mathrm{Mo}$${(}^{50}$Cr,3p) reaction at 220 MeV with both backed and thin self-supporting targets. The high-spin properties have been followed up to a spin of 47/2. The \ensuremath{\pi}${\mathit{h}}_{11/2}$ yrast band and its unfavored signature partner both exhibit backbends due to ${\mathit{h}}_{11/2}$ proton alignment. The two signatures of a \ensuremath{\pi}${\mathit{g}}_{7/2}$(${\mathit{d}}_{5/2}$) band above the ${\mathit{h}}_{11/2}$ proton alignment were also identified. Interpretations of other structures are discussed.