In-beam $\gamma$-ray spectroscopy with the reactions ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$ + ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ and ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ + ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ at beam energies from 80 to 99 MeV were used to study high-spin states in neutron-deficient nuclei in the mass $A\sim 80$ region. Measurements of $\gamma$-ray energies, intensities, angular distributions, excitation functions, and $\gamma -\gamma$ coincidences were used to assign new levels in ${}_{}{}^{79}{}_{}{}^{}\mathrm{Rb}$ and ${}_{}{}^{80}{}_{}{}^{}\mathrm{Sr}$. For the first time, high-spin states in ${}_{}{}^{81}{}_{}{}^{}\mathrm{Sr}$ have been observed.

NUCLEAR REACTIONS ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$(${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$,$\mathrm{xpyn}\gamma$) and ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}$(${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$,$\mathrm{xpyn}\gamma$) $E_{\mathrm{lab}}=80-99\mathrm{}$ MeV; measured $E_{\gamma }$, $I_{\gamma }$, $\gamma -\gamma$ coincidences, $\sigma (E_{\gamma },E)$, and $\sigma (E_{\gamma },\theta )$; ${}_{}{}^{79}{}_{}{}^{}\mathrm{Rb}$, ${}_{}{}^{80}{}_{}{}^{}\mathrm{Sr}$, and ${}_{}{}^{81}{}_{}{}^{}\mathrm{Sr}$ deduced levels, $J^{\pi }$. Enriched targets.

• Received 13 August 1981

DOI:https://doi.org/10.1103/PhysRevC.25.1325