Level structure of 70Se

The level structure of $^{70}\mathrm{Se}$ was studied via the $^{58}\mathrm{Ni}$($^{14}\mathrm{N}$,$\mathrm{pn}$)$^{70}\mathrm{Se}$ reaction at a beam energy of 38 MeV. Measurements were made of $\ensuremath{\gamma}$-ray singles and $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ coincidence spectra, $\ensuremath{\gamma}$-ray angular distributions, and $\ensuremath{\gamma}\ensuremath{-}\ensuremath{\gamma}$ directional correlations. Level energies, decay modes, spins and parities, $\ensuremath{\gamma}$-ray mixing ratios, and $\ensuremath{\gamma}$-ray branching ratios were deduced. The levels in the yrast band through ${8}^{+}$, a tentative second (${0}^{+}$) state at 2011.2 keV, and a ${3}^{\ensuremath{-}}$ state at 2519.2 keV are some of the new results obtained from the present investigation. The moment-of-inertia plot shows a break around ${6}^{+}$ for the yrast levels, which is attributed to band crossing. Interacting boson approximation calculations were performed and are compared with the experimental values for the energy levels.NUCLEAR REACTIONS $^{58}\mathrm{Ni}$($^{14}\mathrm{N}$,$\mathrm{pn}$)$^{70}\mathrm{Se}$, $E=38$ MeV; measured ${E}_{\ensuremath{\gamma}}$, ${I}_{\ensuremath{\gamma}}$, $\ensuremath{\gamma}(\ensuremath{\theta})$, $\ensuremath{\gamma}\ensuremath{\gamma}(\ensuremath{\theta})$; $^{70}\mathrm{Se}$ deduced levels, $J$, $\ensuremath{\pi}$, $\ensuremath{\delta}$, $\ensuremath{\gamma}$ branching.