411 research outputs found

    Neutron Transfer Studied with a Radioactive beam of 24Ne, using TIARA at SPIRAL

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    A general experimental technique for high resolution studies of nucleon transfer reactions using radioactive beams is briefly described, together with the first new physics results that have been obtained with the new TIARA array. These first results from TIARA are for the reaction 24Ne(d,p)25Ne, studied in inverse kinematics with a pure radioactive beam of 100,000 pps from the SPIRAL facility at GANIL. The reaction probes the energies of neutron orbitals relevant to very neutron rich nuclei in this mass region and the results highlight the emergence of the N=16 magic number for neutrons and the associated disappearance of the N=20 neutron magic number for the very neutron rich neon isotopes.Comment: Proceedings of the Carpathian Summer School of Physics, Mamaia-Constanta, Romania, 13-24 June 200

    Document interpretation using perceptive cycles to build coherent objects. Application to the french cadastral maps

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    The methodology we have used for the interpretation of the French cadastral documents focuses on a number of studied results of the visual perception and a hierarchical description of the document. The strategy used has been based on the « model » document, employing a mixed approach including various « points of view » about the image to be processed. The results of this mixed analysis reveal the appearance of non-interpretable objects on the cadasrer, due to the presence of incoherent semantics. Thanks to the return cycles between the high and low level processing, an analytical strategy is proposed and allows, in order to independently cure the incoherence, thus to attain the most reliable interpretation of the cadastral map.Notre méthodologie d'interprétation des documents cadastraux français s'appuie sur un certain nombre de résultats d'études sur la perception visuelle ainsi que sur une description hiérarchisée du document. La stratégie utilisée, basée sur le « modèle » du document, repose sur une approche mixte comportant différents « points de vue » de l'image à traiter. Les résultats de cette analyse mixte mettent en évidence l'apparition d'objets non interprétables au sens du cadastre, du fait de la présence d'incohérences sémantiques. Une stratégie d'analyse est alors proposée et permet, grâce à des cycles d'aller-retours entre les traitements hauts et bas niveaux, de résoudre les incohérences de façon autonome, ceci afin d'interpréter au plus sûr la planche cadastrale

    Geographic map understanding : Algorithms for hydrographic and road networks reconstruction

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    The French Institut Géographique National (IGN) wants to develop an automated map understanding system, for the geographical maps at scale 1/25000. The aim is to automatically convert the 2000 cartographic paper-maps in a geographical objects database, directly usable by a GIS. This paper describes a high-level method for the automated reconstruction of the network graphs, represented on the French geographic maps . This method is applied to the hydrographic and road networks, symbolized with dashed lines, interrupted solid lines and fragmented textured areas . The graph theory paradigm is used, which allows to naturally model those networks by graphs, and to formalize the constraints for their reconstruction . A priori knowledges on natural and cartographic networks are directly used in the reconstruction process, and translated either as invariants the networks must verify during the reconstruction, either as quality criterion for the likely considered connexions .L'Institut Géographique National (IGN) a pour objectif de développer sur la carte IGN au 1/25000 un système d'interprétation totalement automatique et complet de la carte. Le but est de convertir automatiquement le fond de cartes existant sous forme papier, en une base de données d'objets géographiques directement manipulables par un SIG. Cet article décrit une méthode générale de haut niveau pour la reconstruction automatique des graphes des réseaux représentés sur les cartes géographiques. Elle a été appliquée aux réseaux hydrographiques et routiers qui sont essentiellement composés de lignes tiretées, de traits pleins interrompus et d'objets surfaciques interrompus. Le formalisme utilisé est celui de la théorie des graphes, qui permet de modéliser naturellement ces réseaux et d'expliciter les contraintes liées à leur reconstruction. Les connaissances a priori sur les réseaux réels et cartographiques sont directement intégrées dans le processus de reconstruction, et traduites soit comme des invariants que doivent vérifier les réseaux en cours de reconstruction, soit comme des mesures de qualité sur les connexions vraissemblables envisagées

    Structure of 12Be: intruder d-wave strength at N=8

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    The breaking of the N=8 shell-model magic number in the 12Be ground state has been determined to include significant occupancy of the intruder d-wave orbital. This is in marked contrast with all other N=8 isotones, both more and less exotic than 12Be. The occupancies of the 0 hbar omega neutron p1/2-orbital and the 1 hbar omega, neutron d5/2 intruder orbital were deduced from a measurement of neutron removal from a high-energy 12Be beam leading to bound and unbound states in 11Be.Comment: 5 pages, 2 figure

    Exploring the performance of the spectrometer prisma in heavy zirconium and xenon mass regions

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    We present results from two recent runs which illustrate the performance of the PRISMA spectrometer in the proximity of the upper limit of its operational interval, namely 96Zr + 124Sn at Elab = 500 MeV and 136Xe + 208Pb at Elab = 930 MeV. In the latter run, the γ array CLARA also allowed us to identify previously unknown γ transitions in the nuclides 136Cs and 134I

    First observation of excited states in 173Hg

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    The neutron-deficient nucleus 173Hg has been studied following fusion-evaporation reactions. The observation of gamma rays decaying from excited states are reported for the first time and a tentative level scheme is proposed. The proposed level scheme is discussed within the context of the systematics of neighbouring neutron-deficient Hg nuclei. In addition to the gamma-ray spectroscopy, the alpha decay of this nucleus has been measured yielding superior precision to earlier measurements.Comment: 5 pages, 4 figure

    Coulomb excitation of exotic nuclei at the R3B-LAND setup

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    Exotic Ni isotopes have been measured at the R3B-LAND setup at GSI in Darmstadt, using Coulomb excitation in inverse kinematics at beam energies around 500 MeV/u. As the experimental setup allows kinematically complete measurements, the excitation energy was reconstructed using the invariant mass method. The GDR and additional low-lying strength have been observed in 68Ni, the latter exhausting 4.1(1.9)% of the E1 energy-weighted sum rule. Also, the branching ratio for the non-statistical decay of the excited 68Ni nuclei was measured and amounts to 24(4)%.Comment: 11 pages, 7 figures. Invited Talk given at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS
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