127 research outputs found

    El complejo de dunas eólicas de la Playa de Frouxeira (Meirás-Valdoviño, La Coruña)

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    [Resumen] Dentro del complejo dunar, situado en la parte posterior de la playa de Frouxeira, se han distinguido varios tipos de dunas : montículos aislados, remontantes, parabólicas y blow-outs y cartografiados en cuatro subzonas: dunas activas, subrecientes, remontantes y fósiles. Se establecen las características texturales de las arenas dunares y de playa, tanto granulométricas como a partir de los índices de correlación lineal entre los diferentes parámetros, además del contenido carbonatado. Finalmente, se determina la evolución sedimentaria y su relación con el resto de la cornisa cantábrica, mediante los datos prehistóricos asociados al medio de depósito[Abstract] Several coastal sand dunes are classified ( isolated mounds, climbing, parabolic and blow-outs ) and they are distributed in four areas: active, subrecent, climbing and fossil ones. Textural patterns as well granulometric parameters as lineal correlation index among them are stablished. Finally, the sedimentary evolution is determlnated by the help of the prehistoric information from the Asturian and Cantabrian region

    Influence of single-neutron stripping on near-barrier <sup>6</sup>He+<sup>208</sup>Pb and <sup>8</sup>He+<sup>208</sup>Pb elastic scattering

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    The influence of single-neutron stripping on the near-barrier elastic scattering angular distributions for the 6,8He+208Pb systems is investigated through coupled reaction channels (CRC) calculations fitting recently published data to explore the differences in the absorptive potential found in the scattering of these two neutron-rich nuclei. The inclusion of the coupling reduces the elastic cross section in the Coulomb-nuclear interference region for 8He scattering, whereas for 6He its major impact is on the large-angle elastic scattering. The real and imaginary dynamic polarization potentials are obtained by inverting the CRC elastic scattering S-matrix elements. These show that the main absorptive features occur between 11 and 12 fm for both projectiles, while the attractive features are separated by about 1 fm, with their main structures occurring at 10.5 fm for 6He and 11.5 fm for 8He

    Nuevas aportaciones al conocimiento de la evolución tectonometamórfica del complejo de Cabo Ortegal (NW de España)

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    [Resumen] El Complejo de Cabo Ortegal es una unidad a16ctona constituida en gran parte por rocas ultrabásicas, básicas y neises. Estas rocas han sufrido un metamorfismo polifásico en el que se distinguen cuatro episodios, de forma que el grado más elevado se alcanza durante la primera fase (facies granulita y eclogita), teniendo lugar después una retrogradación progresiva hasta la facies de los esquistos verdes. La evolución de la deformación ha tenido también lugar en cuatro fases, de forma que la primera es posterior a los dos primeros episodios metamórficos. Las tres primeras fases de deformación representan una importante deformación por cizalla tangencial, mientras que la cuarta da lugar al amplio sinforme en cuyo núcleo se sitúa el complejo. Las rocas de Cabo Ortegal representan probablemente una secuencia ofiolítica subducida durante el Ordov!cico y obducida con posterioridad al Devónico inferior como con secuencia de una colisión continental.[Abstract] The Cabo Ortegal Complex is an allochthonous unit made up of ultrabasic rocks, basic rocks and gneisses. These rocks have suffered a poliphasic metamorphism in which four episodes can be established. The highest degree of metamorphism (granulitic and eclogitic facies) took place during the first phase followed a~erwards by a progressive retrogresion to greenschist facies. Four phases of deformation can also be distinguished being the first later than the first two metamorphic episodes. The three earlier tectonic phases represent an important sheardeformation while the forth gives way to the wide sinform of Cabo Ortegal. The rocks of the Cabo Ortegal Complex would be an ophiolitic sequence subducted during Ordovician times and obducted after the lower Devonian, due to a continental collision

    Interaction of 8 He with 208Pb at near-barrier energies: 4 He and 6 He production

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    Spanish Ministry of Economy and Competitiveness-FPA-2010-22131-CO2-01 (FINURA) y FPA2013-47327-C2-1-RMinistry of Science and Higher Education of Poland-N202 033637National Science Centre of Poland-2013/08/M/ST2/00257 (LEA-COPIGAL) y 2014/14/M/ST2/00738 (COPIN-INFN Collaboration)European Science Foundation-EUI2009-04163432 (EUROGENESIS

    Observation and Spectroscopy of New Proton-Unbound Isotopes 30Ar and 29Cl: An Interplay of Prompt Two-Proton and Sequential Decay

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    Previously unknown isotopes Ar30 and Cl29 have been identified by measurement of the trajectories of their in-flight decay products S28+p+p and S28+p, respectively. The analysis of angular correlations of the fragments provided information on decay energies and the structure of the parent states. The ground states of Ar30 and Cl29 were found at 2.25+0.15−0.10 and 1.8±0.1  MeV above the two- and one-proton thresholds, respectively. The lowest states in Ar30 and Cl29 point to a violation of isobaric symmetry in the structure of these unbound nuclei. The two-proton decay has been identified in a transition region between simultaneous two-proton and sequential proton emissions from the Ar30 ground state, which is characterized by an interplay of three-body and two-body decay mechanisms. The first hint of a fine structure of the two-proton decay of Ar∗30(2+) has been obtained by detecting two decay branches into the ground and first-excited states of the S28 fragment.A. G., S. K., S. R., and P. S. were supported by the Helmholtz Association Grant No. IK-RU-002. L. V. G. was partly supported by the Ministry of Education and Science of the Russian Federation Grant No. NSh- 932.2014.2. A. F., A. G., L. V. G., S. K., P. S., and R. S. were partly supported by the Russian Foundation for Basic Research Grant No. 14-02-00090-a. This work was partly supported by the Polish National Science Center under Contract No. UMO-2011/01/B/ST2/01943. A. A. C. acknowledges support by the Polish Ministry of Science and Higher Education by Grant No. 0079/DIA/ 2014/43 (Grant Diamentowy). M. P. and X. X. are grateful for a support from the Helmholtz International Center for FAIR (HIC for FAIR). Y. L. was supported by the Helmholtz-CAS Joint Research Group Grant No. HCJRG- 108. J. M. E. acknowledges support from the FPA2009- 08848 contract (MICINN, Spain

    Study of the near-barrier scattering of 8 He on 208 Pb

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    The structure and dynamics of 8He have been studied through the collision process with a 208 Pb target at energies of 22 and 16 MeV, above and below the Coulomb barrier, respectively. The energy and angular distributions of the elastically scattered 8He and the 6,4He fragments were measured. In this paper, we discuss the method used to determine the effective position of the beam spot on the reaction target and the scattering and solid angles of each pixel of the detector array.Ministerio de Economía y Competitividad PA2010-22131-C021-01, FPA2014-59954-C3-1-PMinistry of Science and Higher Education of Poland N202 03363European Science Foundation EUI2009-0416

    Elastic scattering of 8He + 208Pb at 22MeV

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    The dynamics of 8He around the Coulomb barrier is investigated by measuring the energy and angular distribution of the elastic 8He and the 6He and 4He fragment yields in the collision process with a 208Pb target. The experiment was carried out at SPIRAL/GANIL in October 2010. The experimental results will provide information about the relevant reaction mechanisms and the validity of the optical model (OM) when applied to exotic nuclei. In this paper, details of the experimental setup and preliminary results on the elastic scattering for the collision at 22 MeV are presented.Spanish Research Council FPA-2010-22131-CO2-01Ministry of Science and Higher Education of Poland N202 03363

    Reaction of the halo nucleus be on heavy targets at energies around the coulomb barrier

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    Presented at the XXXIII Mazurian Lakes Conference on Physics, Piaski, Poland, September 1–7, 2013.-- et al.New data for the reaction 11Be on 197Au at E lab = 31:9 MeV are presented. The angular distributions of the inelastically scattered 11Be and the 10Be fragments coming from the 11Be dissociation have been extracted and compared with semiclassical and coupled-channels calculations in an angular range θlab = 13deg;-46deg; for the detected Be fragment.This work was supported by the Spanish Government under the projects FPA2009-07387, FPA2009-07653, FPA2009-08848, FPA2012-32443 and Consolider CPAN CSD2007-00042; the Helmholtz Association (HGT) through the Nuclear Astrophysics Virtual Institute (VH-VI-417); ATI Sistemas; a Natural Sciences and Engineering Research Council of Canada grant. TRIUMF receives federal funding via a contribution agreement through the National Research Council of Canada.Peer Reviewe

    Scattering of light halo nuclei on heavy target at energies around the Coulomb barrier

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    This is an Open Access article distributed under the terms of the Creative Commons Attribution License 2.0.-- et al. and the E1104 S1202 collaborations at TRIUMF.-- Trabajo presentado a la: "25th International Nuclear Physics Conference" (INPC), celebrada en Firenze (Italia) del 2 al 7 de junio de 2013.We report here on experiments performed at TRIUMF to study the scattering of the light halo nuclei 11Li on lead at energies below and around the Coulomb barrier. The the elastic and break-up differential cross section are interpreted in the framework of Continuum-Discretized Coupled-Channel calculations. The departure from Rutherford scattering at energies below the barrier is well beyond the behavior of normal nuclei.This work was supported by the Spanish CICYT under the project numbers FPA2009-07387, FPA2012-32443, FPA2009-08848, FPA2009-07653, and FPA2010-22131-C02-01 and by the Consolider Ingenio 2010 Program CPAN (CSD2007- 00042).Peer Reviewe
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