Electromagnetic Transition Rates inNi56

The lifetimes of the first two excited states in ${}_{}{}^{56}{}_{}{}^{}\mathrm{Ni}$ have been investigated using the reaction ${}_{}{}^{54}{}_{}{}^{}\mathrm{Fe}({}_{}{}^3{}_{}{}^{}\mathrm{He},n\gamma ){}_{}{}^{56}{}_{}{}^{}\mathrm{Ni}$ and the Doppler-shift attenuation method. Pulse-shape discrimination was employed for the neutron-$\gamma$-ray coincidence measurements. These measurements lead to the following mean lives: $\tau \left(2699\mathrm{} \mathrm{keV}\right)={76}_{-24\mathrm{}}^{+49\mathrm{}}$ fsec and $\tau \left(3924\mathrm{} \mathrm{keV}\right)>\mathrm{}1\mathrm{}$ psec. The $E2\mathrm{}$ transition strength for the $2^{+}\to 0^{+}$ transition is compared to shell-model predictions.