[en] Excited states in ¹²⁶Ce have been observed with the GAMMASPHERE γ-ray detector array, used in conjunction with the MICROBALL charged-particle detector. The reaction ⁶⁴Zn(⁶⁴Zn,xpnα) (beam energy 260 MeV) was used to populate a wide range of nuclei in the neutron-deficient region with A∼120. ¹²⁶Ce was populated via the 2p evaporation channel. The three previously observed bands have been extended to higher spins and some other structures have been identified. The yrast band shows evidence of a delayed neutron alignment occurring at a rotational frequency ω∼0.5 MeV/ℎ as observed in the neighboring odd-A nucleus ¹²⁷Pr. One of the two excited bands shows evidence for a similar crossing at a slightly lower frequency and also exhibits a sudden gain in alignment at ω=0.57 MeV/ℎ. The third band may involve the coupling of a γ-vibrational state. All three rotational bands are discussed in terms of standard and extended cranked shell model calculations

[en] Excited states have been identified in the very neutron-deficient ₅₅¹¹⁷Cs₆₂ nucleus. High-spin spectroscopy has been performed using the Gammasphere array, and the assignment of gamma-ray transitions to ¹¹⁷Cs has been made in a separate experiment in which gamma rays were detected in coincidence with x rays and with recoiling evaporation residues. A previously observed sequence of five gamma rays has been extended by 11 transitions, to high spin, and has been identified as the yrast π(h_11/2)[550]1/2^- band of ¹¹⁷Cs. Two additional bands have been observed and are tentatively assigned to be based on protons in the [404]9/2⁺ and [422]3/2⁺ orbitals. Alignments of pairs of h_11/2 neutrons and protons are observed in all of the bands. The alignments are compared to cranked Woods-Saxon calculations, and are discussed with respect to the effects of a neutron-proton interaction. Of particular interest are the features of the ν(h_11/2)² alignment in the π[550]1/2^- band and of the π(h_11/2)² alignment in the [422]3/2⁺ band. The frequencies of these alignments can be qualitatively explained only if a neutron-proton interaction is taken into account

[en] In this contribution an experimental study of the deep-inelastic reaction ₄₀⁹⁶Zr+₅₀¹²⁴Sn at 530 MeV, using the GASP and PRISMA-CLARA arrays, is presented. The experiments populate a wealth of projectile-like and target-like binary fragments, in a large neutron-rich region around N ≥ 50 and Z ≈ 40. Preliminary results on the study of the yrast and near-yrast states for ⁹⁵Nb will be shown, along with a comparison of the experimental yields obtained in the experiments

No abstract available

[en] Excited states in ¹⁴⁷La, populated in spontaneous fission of ²⁵²Cf have been reinvestigated by means of γ spectroscopy, using high-fold γ coincidences measured with Gammasphere array of Ge detectors. The 229.5-keV level, which has been assigned spin-parity 9/2^- in a recent evaluation, is shown to have spin-parity 11/2^-. Consequently, the ground state has spin-parity 5/2⁺. Excited levels in ¹⁴⁷La have been arranged into a parity-doublet structure, showing that at medium excitation energy the ¹⁴⁷La nucleus may have octupole deformation. In conclusion, the B(E1) rates in ¹⁴⁷La, which are factor four lower than in ¹⁴⁵La, suggest that the electric dipole moment in ¹⁴⁷La is depresses by an extra mechanism, probably connected with the population of particular neutron orbitals.

[en] Measurements of g-factors of excited states in barium and cerium fission fragments have been performed using time-integral perturbed angular correlations between secondary-fragment γ rays. Larmor precession angles have been obtained for the first I^π = 2⁺ states in ^144,146Ba and ^146,148Ce as well as for the state at 117 keV in ¹⁴³Ba, the state at 114 KeV in ¹⁴⁵Ba and the first 4⁺ state in ¹⁵⁰Ce. The deduced g-factor for the 2⁺ state in ¹⁴⁶Ba provides substantiating evidence for a downward trend in 2⁺ g-factors with increasing neutron number, in line with Interacting Boson Model predictions for the neutron-rich barium isotoes, assuming the quenching of the Z = 64 shell gap for N > 88. The static hyperfine fields for implanted barium and cerium isotopes are found to be opposite in sign. These results constitute the first use of secondary-fragment γ-ray emission in the determination of g-factors of excited states in fission fragments

[en] The neutron-rich Mn isotopes from A=59 to 63 have been studied through multi-nucleon transfer reactions by bombarding a ²³⁸U target with a beam of ⁷⁰Zn at an energy of E_lab=460 MeV. Prompt γ rays measured by the CLARA array have been identified unambiguously for each nucleus, using coincidence relationships with ions detected in the high-acceptance magnetic spectrometer PRISMA. The new data extends the knowledge of the low-lying level structure of Mn isotopes, which is discussed in terms of the systematics of the region. Results are compared with large-scale shell-model calculations using different effective interactions and valence spaces

[en] Excited states of ₁₇³⁸Cl₂₁ were populated in binary grazing reactions during the interaction of a beam of ₁₆³⁶S₂₀ ions of energy 215 MeV with a ₈₂²⁰⁸Pb₁₂₆ target. The combination of the PRISMA magnetic spectrometer and the CLARA γ-ray detector array was used to identify the reaction fragments and to detect their decay via γ-ray emission. A level scheme for ³⁸Cl is presented and discussed within the context of the systematics of neighboring nuclei and is compared with the results of state-of-the-art shell-model calculations.

[en] Excited states in the neutron-rich isotopes ^57-60Mn have been studied with fusion-evaporation reactions induced by ⁴⁸Ca beams at 130 MeV on ^13,14C targets. Level schemes have been deduced reaching spins of ∼16(ℎ/2π) and ∼27(ℎ/2π)/2 in the odd-odd and odd-even isotopes, respectively. States with natural parity within an fp model space are compared to the predictions of large-scale shell-model calculations using the recently developed GXPF1A effective interaction. Quasirotational structures are evident in all of the isotopes and are discussed in terms of the deformation-driving potential of the ν1g_9/2 intruder orbital. It is apparent that an enlarged model space, incorporating at least the 1g_9/2 intruder state, is necessary to reproduce the observed experimental systematics in a more satisfactory manner.

[en] The structure of the neutron-rich isotopes ^59,60Fe has been studied with the Gammasphere detector array using fusion-evaporation reactions. Level schemes for these nuclei are presented which have been extended to spins of ∼20(ℎ/2π). Both isotopes exhibit regular, near-yrast γ-decay sequences which are generated by the intrusion of the g_9/2 orbital into the fp shell-model space. Lower-spin, natural-parity levels are discussed within the context of shell-model calculations using the GXPF1A interaction in the full fp model space. Experimental features of the high-spin bands are compared with total Routhian surface calculations