Superdeformation in 91Tc

A high-spin rotational band with 11 γ-ray transitions has been observed in 91Tc. The dynamical moment of inertia as well the transition quadrupole moment of 8.1-1.4/+1.9 eb measured for this band show the characteristics of a superdeformed band. However, the shape is more elongated than in the neighbouring A = 80-90 superdeformed nuclei. Theoretical interpretations of the band within the cranked Strutinsky approach based on two different Woods-Saxon potential parameterisations are presented. Even though an unambiguous configuration assignment proved difficult, both calculations indicate a larger deformation and at least three additional high-N intruder orbitals occupied compared to the lighter SD nuclei

γ-ray spectroscopy of neutron-deficient 123Ce

Excited states have been identified in the very neutron-deficient Z=58 nucleus 123Ce. This is the most neutron-deficient odd-A cerium isotope in which excited states have been identified. The states have been unambiguously assigned to 123Ce by detecting de-excitation γ rays in coincidence with evaporated charged particles and neutrons. Three rotational bands, each consisting of at least eight E2 transitions, have been observed. The bands have tentatively been assigned to be based on neutrons in g7/2 and h11/2 orbitals. Two of the bands have been assigned to be signature partners, although no interband transitions have been observed. The aligned angular momenta of the bands have been studied in comparison with neighboring nuclei and with the results of Woods-Saxon cranking calculations. Observation of the deformation-dependent π(h11/2)2 quasiparticle alignment at 0.36MeV/ in each of the bands suggests a quadrupole deformation of β2 0.3, in good agreement with theoretical predictions for the suggested possible configuration assignments

Superdeformation in the Doubly Magic Nucleus 4020Ca20

Rotational band with seven γ-ray transitions between states with spin 2ħ and 16ħ has been observed in the doubly magic, self-conjugate nucleus 4020Ca20. The measured transition quadrupole moment of 1.80+0.39−0.29eb indicates a superdeformed shape with a deformation β2 = 0.59+0.11−0.07. The features of this band are explained by cranked relativistic mean field calculations to arise from an 8-particle 8-hole excitation

Core-excited smoothly terminating band in 114Xe

High-spin states have been studied in neutron-deficient 54114Xe, populated through the 58Ni(58Ni,2p) fusion-evaporation reaction at 230 MeV. The Gammasphere γ-ray spectrometer has been used in conjunction with the Microball charged-particle detector in order to select evaporation residues of interest. The yrast band has been greatly extended to a tentative spin of 52hℏ and shows features consistent with smooth band termination. This band represents the first evidence for a core-excited (six-particle, two-hole) proton configuration above Z = 53

Observation of excited states in the near-drip-line nucleus 125Pr

High-spin states have been observed in the near-drip-line nucleus 125Pr following the reaction 64Zn(64Zn, p2n). The detection of charged particles and neutrons evaporated from the compound system, along with the M/q of the recoiling nucleus, have allowed the identification of excited states in 125Pr and the unambiguous assignment of five rotational structures to this nucleus. This is the most neutron-deficient Pr isotope in which excited states have been observed. The strongest band is identified as the h11/2 single-quasiproton configuration, and is observed to a maximum spin of I = (67/2hℏ). Another structure is interpreted as the g9/2 proton hole state, which is associated with bands of enhanced deformation observed in several nuclei in this mass region. These two bands are compared with analogous bands in the heavier odd-A Pr isotopes and changes in deformation are discussed

Probing sd-fp cross-shell interactions via terminating configurations in Sc42,43

An experimental study of the lower fp-shell nuclei Sc42,43 was performed via αpn and αp evaporation, respectively, from Ne20 + Si28 and Mg24 + Mg24 fusion-evaporation reactions. The experiments were conducted with the Gammasphere and Microball detector arrays. The level schemes of both nuclei have been extended considerably. Terminating states associated with the f7/2n and d3/2-1f7/2n+1 configurations were identified in each nuclide and incorporated into detailed comparisons with neighboring nuclei and with shell model calculations. The energy differences between the terminating states provide a test of the sd-fp cross-shell interactions in these calculations

Yrast and near-yrast excitations up to high spin in 10048Cd52

The gamma decay of excited states in the nucleus 100Cd, which is two proton holes and two neutrons away from doubly magic (N=Z=50) 100Sn, has been studied with the Gammasphere array following the 46Ti(58Ni,2p2n) reaction at 215 MeV. Residues were identified by detection of evaporated charged particles in the Microball CsI array, by neutron detection in a set of liquid scintillator detectors, and by a tag on the delayed gamma-ray decay of the known 8+ isomeric state. The level scheme has been extended up to 20ℏ in angular momentum and to nearly 10 MeV in excitation energy. The results are compared with shell-model calculations

High-spin shell-model states near 56^{\bf 56}Ni

High-spin states of nuclei near doubly magic $^{56}$Ni were studied with the reaction $^{28}$Si($^{36}$Ar,x$p$y$n$z$\alpha$) at 136 MeV beam energy. The Gammasphere array in conjunction with the $4\pi$ charged-particle detector array Microball and neutron detectors were used to detect $\gamma$ rays in coincidence with evaporated light particles. The resulting extensive decay schemes of $^{54}$Fe, $^{54,55}$Co, $^{56,57}$Ni, and $^{58}$Cu are compared to shell model calculations in the $fp$ shell