Transitional nuclei in the rare-earth region: Energy levels and structure of 130,132Ce, 132,134Nd, and 134Pm, via beta decay of 130,132Pr, 132,134Pm, and 134Sm.

Abstract

An investigation of low-lying energy levels of $^{130,132}\mathrm{Ce}$, $^{132,134}\mathrm{Nd}$, and $^{134}\mathrm{Pm}$ has been made via \ensuremath{\beta} decay, especially of those levels in the ${\mathit{K}}^{\mathrm{\ensuremath{\pi}}}$=${2}^{+}$ gamma band in the even-even nuclei. The radioactive parent nuclei were produced by the $^{92}\mathrm{Mo}$${(}^{46}$Ti,xpyn) and $^{112}\mathrm{Sn}$${(}^{28}$Si,xpyn) reactions with bombarding energies of 170 to 240 MeV. An isotope separator enabled A=134 mass identification. Level schemes of these five nuclei were constructed from \ensuremath{\gamma}-\ensuremath{\gamma}-t coincidence data. The \ensuremath{\beta}-decay half-lives of the parent nuclei, $^{130}\mathrm{Pr}$, $^{132}\mathrm{Pr}$, $^{132}\mathrm{Pm}$, $^{134}\mathrm{Pm}$, and $^{134}\mathrm{Sm}$, were determined to be 40\ifmmode\pm\else\textpm\fi{}4, 96\ifmmode\pm\else\textpm\fi{}18, 8.8\ifmmode\pm\else\textpm\fi{}0.8, 23\ifmmode\pm\else\textpm\fi{}2, and 9.3\ifmmode\pm\else\textpm\fi{}0.8 s, respectively. The suitability of the proton-neutron interaction boson model in describing $^{130}\mathrm{Ce}$, $^{132}\mathrm{Ce}$, $^{132}\mathrm{Nd}$, and $^{134}\mathrm{Nd}$ is supported by the comparison of experimental relative E2 transition probabilities with proton-neutron interaction boson model predictions.