Collective and broken pair states of 65,67Ga

Excited states of 65Ga and 67Ga nuclei were populated through the 12C(58Ni,αp) and 12C(58Ni,3p) reactions, respectively, and investigated by in-beam γ-ray spectroscopic methods. The NORDBALL array equipped with a charged particle ball and 11 neutron detectors was used to detect the evaporated particles and γ rays. The level schemes of 65,67Ga were constructed on the basis of γγ-coincidence relations up to 8.6 and 10 MeV excitation energy, and Iπ=27/2 and 33/2+ spin and parity, respectively. The structure of 65,67Ga nuclei was described in the interacting boson-fermion plus broken pair model, including quasiproton, quasiproton-two-quasineutron, and three-quasiproton fermion configurations in the boson-fermion basis states. Most of the states were assigned to quasiparticle + phonon and three quasiparticle configurations on the basis of their electromagnetic decay properties

Pronounced Shape Change Induced by Quasiparticle Alignment

Mean lifetimes of high-spin states of 74Kr have been determined using the Doppler-shift attenuation method. The high-spin states were studied using the 40Ca(40Ca,α2p) reaction at a beam energy of 160 MeV with the GASP γ-ray spectrometer. The ground-state band and negative parity side band show the presence of three different configurations in terms of transitional quadrupole deformations. A dramatic shape change was found along the ground-state band after the S-band crossing. The deduced quadrupole deformation changes are well reproduced by cranked Woods-Saxon Strutinsky calculations

Yrast level structure of the neutron-deficient N = 80 isotones 146Dy, 147Ho and 148Er up to high-spin values

High-spin level schemes of the N = 80 isotones 146Dy, 147Ho and 148Er have been investigated by in-beam \u3b3-ray spectroscopic methods using the NORDBALL Compton-suppressed multidetector array including proton and neutron selection. The projectile-target system 58Ni + 92Mo at 260 MeV beam energy has been used to produce the neutron-deficient N = 80 isotones. The previously known schemes have been extended to considerably higher spin and exitation energy, up to I = 23?, E x 48 8.9 MeV in 146Dy, I = 53/2?, E x 48 8.7 MeV in 147Ho and I = 23?, E x 48 9.6 MeV in 148Er. The results are discussed in terms of the spherical shell model. Many of the levels can be described within this framework