Suchergebnisse

M. Klintefjord et al. -- 11 pags., 8 figs., 1 tab. -- Open Access funded by Creative Commons Atribution Licence 4.0 ; Lifetimes of the 41+ states in Fe62,64 and the 11/21- states in Co61,63 and Mn59 were measured at the Grand Accélérateur National d'Ions Lourds (GANIL) facility by using the Advanced Gamma Tracking Array (AGATA) and the large-acceptance variable mode spectrometer (VAMOS++). The states were populated through multinucleon transfer reactions with a U238 beam impinging on a Ni64 target, and lifetimes in the picosecond range were measured by using the recoil distance Doppler shift method. The data show an increase of collectivity in the iron isotopes approaching N=40. The reduction of the subshell gap between the ν2p1/2 and ν1g9/2 orbitals leads to an increased population of the quasi-SU(3) pair (ν1g9/2,ν2d5/2), which causes an increase in quadrupole collectivity. This is not observed for the cobalt isotopes with N<40 for which the neutron subshell gap is larger due to the repulsive monopole component of the tensor nucleon-nucleon interaction. The extracted experimental B(E2) values are compared with large-scale shell-model calculations and with beyond-mean-field calculations with the Gogny D1S interaction. A good agreement between calculations and experimental values is found, and the results demonstrate in particular the spectroscopic quality of the Lenzi, Nowacki, Poves, and Sieja (LNPS) shell-model interaction. ; The authors would also like to thank M. Loriggiola, Laboratori Nazionali di Legnaro, and G. Fremont, GANIL, for preparing the target and degrader foils. This project received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement n°654002. Support from the Norwegian Research Council, project grant 213442, is acknowledged. The project has received funding from the Swedish Research Council. This work is supported by the Spanish Ministerio de Economía y Competitividad under contract FPA2014-57196-C5-4-P. One of the authors, A. Gadea, was partially supported byMINECO and Generalitat Valenciana, Spain, under the grants FPA2014- 57196-C5 and PROMETEOII/2014/019, and by EU FEDER ; Peer Reviewed

WOS: 000301813500009 ; A study of the dimensions and performance of a single detector of the future neutron detector array NEDA was performed by means of Monte Carlo simulations, using GEANT4. Two different liquid scintillators were evaluated: the hydrogen based BC501A and the deuterated BC537. The efficiency and the probability that one neutron will trigger a signal in more than one detector were investigated as a function of the detector size. The simulations were validated comparing the results to experimental measurements performed with two existing neutron detectors, with different geometries, based on the liquid scintillator BC501. (C) 2012 Elsevier B.V. All rights reserved. ; Polish Ministry of Science and Higher Education [N N202 073935]; Swedish Research Council; European Union [212692]; LEA COPIGAL; COPIN-IN2P3; Warsaw University of Technology; MICINN, Spain [AIC10-D-000568]; INFN, Italy [AIC10-D-000568]; MICINN; Generalitat Valenciana, Spain [FPA2008-06419, PROMETEO/2010/101] ; This work was partly supported by the Polish Ministry of Science and Higher Education, grant no. N N202 073935, by the Swedish Research Council, by the European Union within the Spiral2 Preparatory Phase project (7t Framework Programme, project no. 212692), by the LEA COPIGAL and COPIN-IN2P3 collaborations, and within the framework of the European Social Fund through the Warsaw University of Technology Development Programme, realised by the Center for Advanced Studies. A. Gadea and E. Farnea acknowledge the support of MICINN, Spain, and INFN, Italy, through the AIC10-D-000568 bilateral action. A. Gadea and T. Huyuk have been partially supported by the MICINN and Generalitat Valenciana, Spain, under grants FPA2008-06419 and PROMETEO/2010/101. We acknowledge help of colleagues from the National Centre for Nuclear Research at Swierk, Poland, in particular of L. Swiderski, and thank them for providing one of the detectors and electronics. Valuable discussions with J.L. Tain, D. Cano-Ott and A. Algora are also acknowledged.

19 pags., 14 figs., 3 tabs. ; A γ-ray spectroscopic study of Po212 was performed at the Grand Accélérateur National d'Ions Lourds, using the inverse kinematics α-transfer reaction C12(Pb208,Po212)Be8 and the AGATA spectrometer. A careful analysis based on γγ coincidence relations allowed us to establish 14 new excited states in the energy range between 1.9 and 3.3 MeV. None of these states, however, can be considered as candidates for the levels with spins and parities of 1- and 2- and excitation energies below 2.1 MeV, which have been predicted by recent α-cluster model calculations. A systematic comparison of the experimentally established excitation scheme of Po212 with shell-model calculations was performed. This comparison suggests that the six states with excitation energies (spins and parities) of 1744 (4-), 1751 (8-), 1787 (6-), 1946 (4-), 1986 (8-), and 2016 (6-) keV, which previously were interpreted as α-cluster states, may in fact be of positive parity and belong to low-lying shell-model multiplets. This reinterpretation of the structure of Po212 is supported by experimental information with respect to the linear polarization of γ rays, which suggests a magnetic character of the 432-keV γ ray decaying from the state at an excitation energy of 1787 keV to the 61+ yrast state, and exclusive reaction cross sections. ; This project has received funding from the European Union's Horizon 2020 research and innovation programme under Grant Agreement No. 654002 and FEDER funds. We furthermore acknowledge support from the Spanish Ministerio de Ciencia, Inovación y Universidades under contracts FPA2014-57196-C5, FPA2017-84756-C4, and SEV-2014-0398, the Generalitat Valenciana under Grant No. PROMETEO/2019/005, the Swedish Research Council (Vetenskapsrådet, VR 2016-3969), and the German BMBF under Contracts No. 05P18PKFN9 and No. 05P19PKFNA. ; Peer reviewed

This second issue of the French Complex Systems Roadmap is the outcome of the Entretiens de Cargese 2008, an interdisciplinary brainstorming session organized over one week in 2008, jointly by RNSC, ISC-PIF and IXXI. It capitalizes on the first roadmap and gathers contributions of more than 70 scientists from major French institutions. The aim of this roadmap is to foster the coordination of the complex systems community on focused topics and questions, as well as to present contributions and challenges in the complex systems sciences and complexity science to the public, political and industrial spheres.