Evolution of γ-vibrations at high spin

Intrinsic collective excitations in deformed nuclei [1] are γ (Y_2,2) and Octupole (Y_3,μ) vibrations; ß (Y_2,0) vibrations are at energies above the pairing gap [2,3] and have not been observed. In the past, experiments on rotating deformed intrinsic structures to populate levels at high spin have been an effective method of revealing details of the underlying microscopic configurations. Not many γ-bands have been extended to high spin due to their distance from the yrast line. However, Coulomb excitation experiments and the use of the very large γ-ray detector arrays have enabled the γ-bands in several nuclei to be extended to much higher spins than previously achieved. We report on recent data on γ-bands at high spin and on the properties of γ-bands in general.