Shape and Structure of $N=Z$ ${}^{64}\mathrm{Ge}$: Electromagnetic Transition Rates from the Application of the Recoil Distance Method to a Knockout Reaction

Transition rate measurements are reported for the $2_1^{+}$ and $2_2^{+}$ states in $N=Z$ ${}^{64}\mathrm{Ge}$. The experimental results are in excellent agreement with large-scale shell-model calculations applying the recently developed GXPF1A interactions. The measurement was done using the recoil distance method (RDM) and a unique combination of state-of-the-art instruments at the National Superconducting Cyclotron Laboratory (NSCL). States of interest were populated via an intermediate-energy single-neutron knockout reaction. RDM studies of knockout and fragmentation reaction products hold the promise of reaching far from stability and providing lifetime information for excited states in a wide range of nuclei.

Figure 1

Experimental data and line-shape fits for the 954-keV $2_1^{+}\to 0_1^{+}$ transition in ${}^{62}\mathrm{Zn}$ (left), 901-keV $2_1^{+}\to 0_1^{+}$ transition in ${}^{64}\mathrm{Ge}$ (middle), and 677-keV $2_2^{+}\to 2_1^{+}$ transition in ${}^{64}\mathrm{Ge}$ (right). In each panel the left/right spectra are for the SeGA rings at $30°/140°$, while top, middle, and bottom spectra are for 0, 200, and $500\mu \mathrm{m}$ target-degrader separations, respectively. The Doppler corrections account for the detector segmentation but not for the angular position of the detector in the array. See text for further details on line-shape calculations.