[en] Lifetimes for decays linking near-yrast states in ¹⁰⁷Cd have been measured using the recoil distance method (RDM). The nucleus of interest was populated via the ⁹⁸Mo(¹²C,3n)¹⁰⁷Cd fusion-evaporation reaction at an incident beam energy of 60 MeV. From the measured lifetimes, transition probabilities have been deduced and compared with the theoretical B(E2) values for limiting cases of harmonic vibrational and axially deformed rotational systems. Our initial results suggest a rotor-like behavior for the structure based on the unnatural-parity, h_11/2 orbital in ¹⁰⁷Cd, providing further evidence for the role of this 'shape-polarizing' orbital in stabilizing the nuclear deformation in the A ∼ 100 transitional region

[en] The gamma-decay of fragments from deep-inelastic and multi-nucleon transfer processes which occur when a beam of ²⁶Mg at 160 MeV is incident on a thin ¹⁵⁰Nd target was studied using the EUROBALL IV array of escape suppressed Ge detectors at Strasbourg. The good resolving power of EUROBALL IV was further increased by combining it with the Binary Reaction Spectrometer (BRS), used for the detection of projectile-like fragments. The BRS allows full kinematic reconstruction of the binary reaction allowing crucial Doppler corrections of gamma-ray spectra to be performed. Some preliminary results are presented. (orig.)

[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] The excited states of the neutron-rich nucleus ₁₅³⁷P₂₂ have been populated in grazing reactions, using a beam of ³⁶S ions (at 215 MeV) delivered onto a thin ²⁰⁸Pb target. Emitted γ rays from excited projectile-like nuclei were detected using the CLARA array of 25 escape-suppressed Ge clover detectors in coincidence with reaction products detected and identified with the PRISMA magnetic spectrometer. A level scheme is presented for ³⁷P together with proposed spin assignments. The level structure of ³⁷P is discussed within the context of shell-model calculations by using an improved sdpf effective interaction

[en] Since the discovery of the breakdown of shell effects in very neutron-rich N=20 and 28 nuclei, studies of the properties of nuclei far from stability have been of intense interest since they provide a unique opportunity to increase our understanding of nuclear interactions in extreme conditions and often challenge our theoretical models.Deep-inelastic processes can be used to populated high spin states of neutron-rich nuclei. In the deep-inelastic processes, an equilibration in N/Z between the target and projectile nuclei is achieved. For most heavy neutron-rich target nuclei, the N/Z ratio is 1.5 - 1.6, while for the possible neutron-rich sdf-shell projectile it is about 1.2. Thus by using deep-inelastic processes one can populate neutron-rich nuclei around N=20 and N=28.New results for the spectroscopy of neutron-rich N=22 36Si and 37P are presented here

[en] Yrast states in the neutron-rich ⁴¹S nucleus have been studied using binary grazing reactions produced by the interaction of a 215-MeV beam of ³⁶S ions with a thin ²⁰⁸Pb target. The magnetic spectrometer, PRISMA, and the γ-ray array, CLARA, were used in the measurements. γ-ray transitions of energy 449 and 638 keV were observed. Results from published intermediate-energy Coulomb excitation measurements in combination with those from the present work have led to the construction of a new ⁴¹S level scheme. Proposed J^π values are based on experimental observation and on model-dependent arguments. The level scheme and published electromagnetic transition probabilities are discussed within the context of state-of-art shell-model calculations using the SDPF-U effective interaction. In contrast with the excellent agreement observed in earlier published work, here there are significant discrepancies between experiment and the results of shell-model calculations.

[en] Yrast states in the neutron-rich ₁₄³³Si₁₉ nucleus have been studied using binary grazing reactions produced by the interaction of a 215-MeV beam of ³⁶S ions with a thin ²⁰⁸Pb target. An experimental setup that combines the large-acceptance magnetic spectrometer PRISMA and the high-efficiency γ-ray detection array CLARA was used in the experiment. Four new γ-ray photopeaks at energies of 971, 1724, 1772, and 2655 keV were observed and assigned to the ³³Si level scheme. The experimental level scheme is compared with the results of 1(ℎ/2π)ω p-sd-pf large-scale shell-model calculations using the recently developed PSDPFB effective interaction; good agreement is obtained. The structure of the populated states of ³³Si is discussed within the context of an odd neutron coupled to states of the ³²Si core.

[en] Yrast states up to (6⁺) in the neutron-rich ⁴⁰S nucleus have been studied using binary grazing reactions produced by the interaction of a 215 MeV beam of ³⁶S ions with a thin ²⁰⁸Pb target. The novel experimental setup that combines the large acceptance magnetic spectrometer, PRISMA, and the high-efficiency γ-ray detection array, CLARA, was used. A new γ-ray transition at an energy of 1572 keV was observed and tentatively assigned to the (6⁺)→(4⁺) transition. A comparison of experimental observations and the results of large-scale 0(ℎ/2π)ω sd-pf shell-model calculations indicates that one- and two-proton excitations from the 2s_1/2 to the 1d_3/2 orbitals play an important role in reproducing the ⁴⁰S yrast level structure and the published B(E2;0_g.s.⁺→2₁⁺) value. The structure of the yrast states of the even-A isotopes of sulfur is interpreted in terms of the configurations of valence protons and neutrons within the context of large-scale 0(ℎ/2π)ω sd-pf shell-model calculations.

[en] Preliminary lifetime values have been measured for a number of near-yrast states in the odd-A transitional nuclei 107Cd and 103Pd. The reaction used to populate the nuclei of interest was 98Mo(12C,3nxα)107Cd, 103Pd, with the beam delivered by the tandem accelerator of the Wright Nuclear Structure Laboratory at an incident beam energy of 60 MeV. Our experiment was aimed at the investigation of collective excitations built on the unnatural parity, ν h11/2 orbital, specifically by measuring the B(E2) values of decays from the excited levels built on this intrinsic structure, using the Doppler Recoil Distance Method. We report lifetimes and associated transition probabilities for decays from the 15/2- and the 19/2- states in 107Cd and the first measurement of the 15/2- state in 103Pd. These results suggest that neither a simple rotational or vibrational interpretation is sufficient to explain the observed structures

[en] A beam of ²⁶Mg at 160 MeV incident on a thin target of ¹⁵⁰Nd was used to initiate deep-inelastic and multi-nucleon transfer reactions. The gamma-decay of the fragments produced in the reaction was studied using the EUROBALL IV array of escape suppressed Ge detectors at Strasbourg combined with the binary reaction spectrometer used to detect the projectile-like fragments. Preliminary results from the experiment are presented