NUCLEAR-STRUCTURE OF ODD-ODD Y-82

Excited states in Y-82 have been investigated via the (Ni(Si,3pn)Y)-Ni-58-Si-28-Y-82 and (Fe(Si,p2n)Y)-Fe-56-Si-29-Y-82 reactions using beams provided by the Florida State University Tandem-LINAC with energies of 95 to 135 MeV. Particle-gamma coincidences with a full-sphere charged-particle detector and an excitation curve were used to assign gamma rays to Y-82. The (Fe(Si,p2n)Y)-Fe-56-Si-29-Y-82 reaction at 95 MeV was used to measure gamma-gamma coincidences with five Compton-suppressed Ge detectors. Lifetimes in the ns and ps ranges were measured using direct timing and the Doppler-shift attenuation method. A level scheme with 39 states was constructed up to tentative spins and parities of (15-) and (21+). In the positive-parity yrast band a phase reversal was observed in the signature splitting at I = 10hBA. The B(Ml) strengths in this band alternate with signature between about 0.1 and 1.0 mu(N)2. The B(E2) strengths of about 90 Weisskopf units are in good agreement with those predicted by Hartree-Fock-Bogolyubov calculations. Particle-rotor calculations indicate a prolate or triaxial core shape for the positive-parity band.