Excitation energies and nuclear lifetimes of levels in ${}_{}{}^{55}{}_{}{}^{}\mathrm{Co}$ have been measured via the reactions ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}({}_{}{}^3{}_{}{}^{}\mathrm{He}, d\gamma ){}_{}{}^{55}{}_{}{}^{}\mathrm{Co}$ induced by 11.0 MeV incident ${}_{}{}^3{}_{}{}^{}\mathrm{He}_{}^{++}{}_{}{}^{}$ particles. The Doppler shifted $\gamma$-ray spectra, taken in coincidence with the outgoing deuterons, were fitted by a line shape analysis program to determine the lifetimes. Experimental results for excitation energies (±1 keV) and lifetimes (ps) are: 2166, ${0.141}_{-0.021\mathrm{}}^{+0.020\mathrm{}}$; 2566, ${0.620}_{-0.090\mathrm{}}^{+0.120\mathrm{}}$; 2940, ≥0.590; 3324, ${0.090}_{-0.012\mathrm{}}^{+0.017\mathrm{}}$; 4166, ${0.050}_{-0.005\mathrm{}}^{+0.010\mathrm{}}$.

NUCLEAR STRUCTURE ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}({}_{}{}^3{}_{}{}^{}\mathrm{He}, d\gamma )$, $E=11\mathrm{}$ MeV; measured $E_{\gamma }$, Doppler shifts; ${}_{}{}^{55}{}_{}{}^{}\mathrm{Co}$ deduced levels, lifetimes.

• Received 18 February 1975

DOI:https://doi.org/10.1103/PhysRevC.12.2084