Spectroscopy of Mirror Nuclei in the Upper-fp Shell Using GRETINA

Isospin symmetry breaking in nuclei of the upper-fp shell has been investigated in a recent experiment at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University (MSU). A $^{78}$Kr primary beam (with energy 150 MeV.A) was fragmented on a Be target to produce a cocktail of secondary beams, including $^{66}$As, $^{65}$Ge, and $^{64}$Ga, which were selected with the A1900 separator. These secondary beams were in turn fragmented at the target position of S800 magnetic spectrograph, which was used to identify neutron-deficient reaction products including $^{62,63}$Ga, $^{63}$Ge, and $^{65}$As. Gamma-rays emitted from excited states in these nuclei were detected with GRETINA, which comprises 28 highly-segmented, tapered hexagonal, close-packed HPGe and is a first generation gamma-ray tracking array. Many new states and transitions have been identified in these nuclei of the upper-fp shell, including a candidate for the T=1 2$^+$ state in $^{62}$Ga. Preliminary results from the analysis of this data will be presented and the implications for our understanding of isospin--symmetry breaking effects will be discussed.