Gamma-rays deexciting ${}_{}{}^{55}{}_{}{}^{}\mathrm{Co}$ levels have been studied in coincidence with deuterons detected in a particle telescope, in the ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}({}_{}{}^3{}_{}{}^{}\mathrm{He},d\gamma ){}_{}{}^{55}{}_{}{}^{}\mathrm{Co}$ reaction. Excitation energies, relative $\gamma$-ray intensities, and Doppler-shift attenuations of 12 levels have been measured. Mean lifetimes and transition strengths are reported. The Doppler-shifted line shape of the 2164→0-keV transition has been analyzed and has been found consistent with the assumption of a single level. Lifetimes of selected levels are: 2164 keV, ${125}_{-20\mathrm{}}^{+25\mathrm{}}$ fs; 3301 keV, ${50}_{-15\mathrm{}}^{+20\mathrm{}}$ fs; 3322 keV, ${45}_{-10\mathrm{}}^{+15\mathrm{}}$ fs; 3641 keV, ${300}_{-100\mathrm{}}^{+150\mathrm{}}$ fs; 4163 keV, ${30}_{-10\mathrm{}}^{+15\mathrm{}}$ fs; 4714 keV, ${300}_{-150\mathrm{}}^{+200\mathrm{}}$ fs; 4719 keV, < 30 fs; and 5172 keV, ${10}_{-5\mathrm{}}^{+10\mathrm{}}$ fs.

NUCLEAR REACTIONS ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}({}_{}{}^3{}_{}{}^{}\mathrm{He},d\gamma )$, $E=12.0\mathrm{}-13.0$ MeV; measured $d\gamma$ coin, $E_{\gamma }$, $I_{\gamma }$, Doppler-shift attenuation. ${}_{}{}^{55}{}_{}{}^{}\mathrm{Co}$ deduced $\tau$.

• Received 2 June 1975

DOI:https://doi.org/10.1103/PhysRevC.13.614