27 research outputs found
Band structures extending to very high spin in Xe126
High-spin states in Xe126 have been populated in the Se82(Ca48,4n)Xe126 reaction in two experiments, one at the VIVITRON accelerator in Strasbourg using the Euroball detector array, and a subsequent one with ATLAS at Argonne using the Gammasphere Ge-detector array. Levels and assignments made previously for Xe126 up to I=20 have been confirmed and extended. Four regular bands extending to a spin of almost I=60, which are interpreted as two pairs of signature partners with opposite parity, are identified for the first time. The α = 0 partner of each pair is connected to the lower-lying levels, whereas the two α = 1 partners remain floating. A fractional Doppler shift analysis of transitions in the strongest populated (Ï€,α)=(-,0) band provides a value of 5.20.50.4 b for the transition quadrupole moment, which can be related to a minimum in the potential-energy surface calculated by the ULTIMATE CRANKER cranked shell-model code at Îμâ‰0.35 and Îâ‰5°. The four lowest bands calculated for this minimum compare well with the two signature pairs experimentally observed over a wide spin range. A sharp upbend at â.,ω~1170 keV is interpreted as a crossing with a band involving the j15/2 neutron orbital, for which pairing correlations are expected to be totally quenched. The four long bands extend to within â5 spin units of a crossing with an yrast line defined by calculated hyperdeformed transitions and will serve as important stepping stones into the spin region beyond 60ħ for future experiments
High-angular-momentum structures in 64Zn
High-angular-momentum states in 64Zn were populated in the 40Ca( 28Si,4p) reaction at a beam energy of 122 MeV. Evaporated, light, charged particles were identified by the Microball, while γ rays were detected using the Gammasphere array. The main focus of this paper is on two strongly coupled, collective bands. The yrast band, which was previously known, has been linked to lower-lying states establishing the excitation energies and angular momenta of in-band states for the first time. The newly identified excited band decays to the yrast band but firm angular-momentum assignments could not be made. In order to interpret these structures cranked-Nilsson-Strutinsky calculations have been performed. The calculations have been extended to account for the distribution of nucleons within a configuration. The yrast collective band is interpreted as based on the π(f 7/2) -1(p 3/2f 5/2) 2(g 9/2) 1 ν(p 3/2f 5/2) 4(g 9/2) 2 configuration. There are several possible interpretations of the second band but it is difficult to distinguish between the different possibilities
Evolution of shapes in \chem{^{59}Cu}
High-spin states in \chem{^{59}Cu} were populated using the
fusion-evaporation reaction \chem{^{28}Si +{} ^{40}Ca} at a beam energy
of 122 MeV. The Gammasphere Ge-detector array in conjunction with the 4
charged-particle detector array Microball allowed for the
detection of -rays in coincidence with evaporated
light particles. The resulting extensive high-spin
decay scheme of \chem{^{59}Cu} is presented, which comprises more than 320
-ray transitions connecting about 150 excited states.
Their spins and parities have been assigned via directional correlations of
-rays emitted from oriented states. Average quadrupole moments of
rotational bands have been determined from the analysis of residual
Doppler shifts. Shell model calculations in the shell are invoked
to study some of the low-spin states, while the experimental characteristics
of the rotational bands are analyzed in the configuration-dependent
cranked Nilsson-Strutinsky (CNS) approach