In-gas-cell laser ionization spectroscopy in the vicinity of 100Sn: Magnetic moments and mean-square charge radii of N=50-54 Ag

In-gas-cell laser ionization spectroscopy studies on the neutron deficient 97-101Ag isotopes have been performed with the LISOL setup. Magnetic dipole moments and mean-square charge radii have been determined for the first time with the exception of 101Ag, which was found in good agreement with previous experimental values. The reported results allow tentatively assigning the spin of 97,99Ag to 9/2 and confirming the presence of an isomeric state in these two isotopes, whose collapsed hyperfine structure suggests a spin of 1/2 . The effect of the N=50 shell closure is not only manifested in the magnetic moments but also in the evolution of the mean-square charge radii of the isotopes investigated, in accordance with the spherical droplet model predictions

Study of bound states in 12Be through low-energy 11Be(d,p)-transfer reactions

The bound states of 12Be have been studied through a 11Be(d,p)12Be transfer reaction experiment in inverse kinematics. A 2.8 MeV/u beam of 11Be was produced using the REX-ISOLDE facility at CERN. The outgoing protons were detected with the T-REX silicon detector array. The MINIBALL germanium array was used to detect gamma rays from the excited states in 12Be. The gamma-ray detection enabled a clear identification of the four known bound states in 12Be, and each of the states has been studied individually. Differential cross sections over a large angular range have been extracted. Spectroscopic factors for each of the states have been determined from DWBA calculations and have been compared to previous experimental and theoretical results

Alpha decay of 176Au

International audienceThe isotope Au176 has been studied in the complete fusion reaction Ca40+Pr141 → 176Au+5n at the velocity filter SHIP (GSI, Darmstadt). The complex fine-structure α decay of two isomeric states in Au176 feeding several previously unknown excited states in the daughter nucleus Ir172 is presented. An α-decay branching ratio of bα=9.5(11)% was deduced for the high-spin isomer in Ir172

Study of bound states in Be-10 by one neutron removal reactions of Be-11

The bound states of Be-10 have been studied by removing single neutrons from Be-11 nuclei. A 2.8 MeV u(-1) beam of Be-11 was produced at ISOLDE, CERN and directed on to both proton and deuteron targets inducing one-neutron removal reactions. Charged particles were detected to identify the two reaction channels (d, t) and (p, d), and the individual states in Be-10 were identified by gamma detection. All bound states but one were populated and identified in the (d, t) reaction. The combination of REX-ISOLDE and MINIBALL allowed for a clean separation of the high-lying states in Be-10. This is the first time these states have been separated in a reaction experiment. Differential cross sections have been calculated for all the reaction channels and compared to DWBA calculations. Spectroscopic factors are derived and compared to values from the litterature. While the overall agreement between the spectrocopic factors is poor, the ratio between the ground state and the first excited state is in agreement with the previous measured ones. Furthermore, a significant population of the 2(2)(+) state is observed, which which may indicate the presence of multi-step processes at our beam energy.Peer reviewe

Detailed α-decay study of 180Tl

International audienceA detailed $\alpha$-decay spectroscopy study of $^{180}\mathrm{Tl}$ has been performed at ISOLDE (CERN). $Z$-selective ionization by the Resonance Ionization Laser Ion Source (RILIS) coupled to mass separation provided a high-purity beam of $^{180}\mathrm{Tl}$. Fine-structure $\alpha$ decays to excited levels in the daughter $^{176}\mathrm{Au}$ were identified and an $\alpha$-decay scheme of $^{180}\mathrm{Tl}$ was constructed based on an analysis of $\alpha$-$\gamma$ and $\alpha$-$\gamma$-$\gamma$ coincidences. Multipolarities of several $\gamma$-ray transitions deexciting levels in $^{176}\mathrm{Au}$ were determined. Based on the analysis of reduced $\alpha$-decay widths, it was found that all $\alpha$ decays are hindered, which signifies a change of configuration between the parent and all daughter states

Single-neutron orbits near Ni-78 : Spectroscopy of the N=49 isotope Zn-79

Peer reviewe

Single-neutron orbits near Ni-78: Spectroscopy of the N=49 isotope Zn-79

5 pags., 6 figs.Single-neutron states in the , isotope 79Zn have been populated using the 78Zn(d, p)79Zn transfer reaction at REX-ISOLDE, CERN. The experimental setup allowed the combined detection of protons ejected in the reaction, and of γ rays emitted by 79Zn. The analysis reveals that the lowest excited states populated in the reaction lie at approximately 1 MeV of excitation, and involve neutron orbits above the shell gap. From the analysis of γ-ray data and of proton angular distributions, characteristic of the amount of angular momentum transferred, a configuration was assigned to a state at 983 keV. Comparison with large-scale-shell-model calculations supports a robust neutron shell-closure for 78Ni. These data constitute an important step towards the understanding of the magicity of 78Ni and of the structure of nuclei in the region.This work was supported by the European Commission through the Marie Curie Actions Contracts Nos. PIEFGA-2011-30096 (R.O.) and PIEFGA-2008-219175 (J.P.), by the Spanish Ministerio de Ciencia e Innovación under contracts FPA2009-13377-C02 and FPA2011-29854-C04, by the Spanish MEC Consolider – Ingenio 2010, Project No. CDS2007-00042 (CPAN), by FWO-Vlaanderen (Belgium), by GOA/2010/010 (BOF KU Leuven), by the Interuniversity Attraction Poles Programme initiated by the Belgian Science Policy Office (BriX network P7/12), by the European Union Seventh Framework Programme through ENSAR, contract no. RII3-CT-2010-262010, and by the German BMBF under contracts 05P09PKCI5, 05P12PKFNE, 05P12RDCIA and 06DA9036I. R.O., R.C., J.F.W.L., V.L. and J.F.S. also acknowledge support from STFC, Grant Nos. PP/F000944/1, ST/F007590/1, and ST/J000183/2