Lifetime measurements in N=Z⁷²Kr

High-spin states in the N = Z nucleus Kr-72 have been populated in the Ca-40(Ca-40, 2 alpha) Kr-72 fusion-evaporation reaction at a beam energy of 165MeV and using a thin isotopically enriched 40Ca target. The experiment, performed at Argonne National Laboratory close to Chicago, USA, employed the Gammasphere array for gamma-ray detection coupled to the Microball array for charged particle detection. The previously observed bands in 72Kr were extended to a higher excitation energy of similar to 24MeV and higher angular momentum of 30h. Using the Doppler-shift attenuation method, the lifetimes of high-spin states were measured for the first time in order to investigate deformation changes associated with the g(9/2) proton and neutron alignments in this N = Z nucleus. An excellent agreement with theoretical calculations including only standard t = 1 np pairing was observed.