In-beam ?-ray spectroscopy in the ground-state proton emitter

Gamma-raytransitions in the ground-stateproton emitter 113Cs have been identified using the reaction 58Ni(58Ni,p2n) at a beam energy of 230 MeV and the recoil decay tagging technique. The first experiment was done using the Recoil Mass Spectrometer at the Holifield Radioactive Ion Beam Facility where γ-ray transitions were detected with 6 Clover and 5 Duet Gedetectors. A follow-up experiment using the GAMMASPHERE-FMA combination at Argonne National Laboratory was performed. Ninety-six Ge and 4 LEPs detectors were used to record recoil-γγ coincidences. Both experiments employed standard recoil mass separation techniques which resulted in the implantation of A=113 reaction products into a double-sided silicon-strip detector. By gating on the energy of the emitted proton and decay time, the correlation between γ rays and the implanted 113Cs could be observed. Initial analysis and comparison with energy level systematics of the Cs isotopes reveal a decay sequence based on the h112 bandhead. Further analysis is required to determine the decay of this sequence to the expected positive parity ground state.