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Background: The population and decay of two-nucleon resonances offer exciting new opportunities to explore dripline phenomena. A proper understanding of these systems requires a solid description of the three-body (core+N+N) continuum. The identification of a state with resonant character from the background of nonresonant continuum states in the same energy range poses a theoretical challenge. Purpose: Establish a robust theoretical framework to identify and characterize three-body resonances in a discrete basis, and apply the method to the two-neutron unbound system Be16. Method: A resonance operator is proposed, which describes the sensitivity to changes in the potential. Resonances, understood as normalizable states describing localized continuum structures, are identified from the eigenstates of the resonance operator with large negative eigenvalues. For this purpose, the resonance operator is diagonalized in a basis of Hamiltonian pseudostates, which in the present work are built within the hyperspherical harmonics formalism using the analytical transformed harmonic oscillator basis. The energy and width of the resonance are determined from its time dependence. Results: The method is applied to Be16 in a Be14+n+n model. An effective core+n potential, fitted to the available experimental information on the binary subsystem Be15, is employed. The 0+ ground state resonance of Be16 presents a strong dineutron configuration. This favors the picture of a correlated two-neutron emission. Fitting the three body interaction to the experimental two-neutron separation energy |S2n|=1.35(10) MeV, the computed width is Γ(0+)=0.16 MeV. From the same Hamiltonian, a 2+ resonance is also predicted with r(2+)=2.42 MeV and Γ(2+)=0.40 MeV. Conclusions: The dineutron configuration and the computed 0+ width are consistent with previous R-matrix calculations for the true three-body continuum. The extracted values of the resonance energy and width converge with the size of the pseudostate basis and are robust under changes in the basis parameters. This supports the reliability of the method in describing the properties of unbound core+N+N systems in a discrete basis. ; This work has been partially supported by the Spanish Ministerio de Ciencia, Innovación y Universidades, and the European Regional Development Fund (FEDER), under Projects No. FIS2017-88410-P, No. FPA2016-77689-C2-1-R, and No. FIS2014-51941-P and by the European Union's Horizon 2020 research and innovation program under Grant No. 654002. ; Peer reviewed

Background: The population and decay of two-nucleon resonances offer exciting new opportunities to explore dripline phenomena. A proper understanding of these systems requires a solid description of the three-body (core+N +N) continuum. The identification of a state with resonant character from the background of nonresonant continuum states in the same energy range poses a theoretical challenge. Purpose: Establish a robust theoretical framework to identify and characterize three-body resonances in a discrete basis, and apply the method to the two-neutron unbound system 16Be. Method: A resonance operator is proposed, which describes the sensitivity to changes in the potential. Resonances,understoodasnormalizablestatesdescribinglocalizedcontinuumstructures,areidentifiedfromthe eigenstates of the resonance operator with large negative eigenvalues. For this purpose, the resonance operator is diagonalizedinabasisofHamiltonianpseudostates,whichinthepresentworkarebuiltwithinthehyperspherical harmonics formalism using the analytical transformed harmonic oscillator basis. The energy and width of the resonance are determined from its time dependence. Results: The method is applied to 16Be in a 14Be+n+n model. An effective core+n potential, fitted to the available experimental information on the binary subsystem 15Be, is employed. The 0+ ground state resonance of 16Be presents a strong dineutron configuration. This favors the picture of a correlated two-neutron emission. Fitting the three body interaction to the experimental two-neutron separation energy |S2n|=1.35(10) MeV, the computed width is (0+)=0.16 MeV. From the same Hamiltonian, a 2+ resonance is also predicted with εr(2+)=2.42 MeV and (2+)=0.40 MeV. Conclusions: The dineutron configuration and the computed 0+ width are consistent with previous R-matrix calculationsforthetruethree-bodycontinuum.Theextractedvaluesoftheresonanceenergyandwidthconverge with the size of the pseudostate basis and are robust under changes in the basis parameters. This supports the reliability of the method in describing the properties of unbound core+N +N systems in a discrete basis. ; Spanish Ministerio de Ciencia, Innovación y Universidades, European Regional Development Fund (FEDER), (FIS2017-88410-P, FPA2016-77689-C2-1-R, FIS2014-51941-P ) ; European Union's Horizon 2020 (No. 654002)

A novel method to extract the B(E1) strength of a weakly bound nucleus from experimental Coulomb dissociation data is proposed. The method makes use of continuum discretized coupled channels (CDCC) calculations, in which both nuclear and Coulomb forces are taken into account to all orders. This is a crucial advantage with respect to the standard procedure based on the Equivalent Photon Method (EPM) which does not properly take into account nuclear distortion, higher order coupling effects, or Coulombnuclear interference terms. The systematic and statistical uncertainties of this procedure are evaluated. The procedure is applied to the 11Be nucleus using two sets of available experimental data at different energies, for which seemingly incompatible B(E1) have been reported using the EPM. We show that the present procedure gives consistent B(E1) strengths, thus solving the aforementioned long-standing discrepancy between the two measurements. ; This work has been partially supported by the Spanish Ministerio de Ciencia, Innovación y Universidades and FEDER funds under projects FIS2017-88410-P and RTI2018-098117-B-C21 and by the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 654002. ; Peer reviewed

Radiative capture reaction rates for 6He, 9Be and 17Ne formation at astrophysical conditions are studied within a three-body model using the analytical transformed harmonic oscillator method to calculate their states. An alternative procedure to estimate these rates from experimental data on low-energy breakup is also discussed. ; Ministerio de Economía y Competitividad FPA2016-77689-C2-1-R, FIS2014-53448-c2-1-P, FIS2014-51941-P ; Junta de Andalucía FQM-160, P11-FQM-7632 ; European Union 654002

11 pages, 10 figures.-- PACS nrs.: 25.60.Dz, 25.60.Gc, 25.60.Bx, 21.10.Gv, 27.20.+n.-- 2nd version of the pre-print: Submitted on 18 Jul 2005 (v1), last revised 17 Nov 2005 (this version, v2), minor corrections made.-- Published in: Nuclear Physics A, Vol.765, Issues 3-4, pages 294-306 (6 February 2006).-- et al. ; Quasi-elastic scattering of 6He at E_lab=27 MeV from 197Au has been measured in the angular range of 6-72 degrees in the laboratory system employing LEDA and LAMP detection systems. These data, along with previously analysed data of 6He + 208Pb at the same energy, are analyzed using Optical Model calculations. The role of Coulomb dipole polarizability has been investigated. Large imaginary diffuseness parameters are required to fit the data. This result is an evidence for long range absorption mechanisms in 6He induced reactions. ; The authors thank the staff at the Cyclotron Research Centre accelerator facility in Louvain-la-Neuve, Belgium, for providing us with an intense and good quality radioactive beam. ORK acknowledges a grant from the Iranian government and support from the University of Sevilla for his stay at this university. PJW, TD, ACS, AL, ADP and WBS would like to acknowledge support from the British EPSRC. AMSB, IMB, MVA, AM, MAGA and JGC would like to acknowledge support from the Spanish MCyT under projects FPA2003-05958 and FPA2005-04460. AMSB acknowledges a research grant from the Spanish MCyT. ; Peer reviewed

6 pages, 1 table, 5 figures.-- El pdf del artículo es la versión pre-print.-- et al. ; The Li-9 + H-2 reaction has been investigated at 2.36 MeV/u at the REX-ISOLDE facility. In this Letter we focus on the Li-10 + p channel which potentially holds spectroscopic information on the unbound nucleus Li-10. The experimental excitation energy spectrum and angular distribution are compared with CCBA calculations. These calculations clearly support the existence of a low-lying (s) virtual state, with a (negative) scattering length of the order a(s) ~ 13-24 fm and a P-1/2 resonance with an energy of E-r ≈ 0.38 MeV and a width of Γ ≈ 0.2 MeV. ; This work has been supported by the European Union Fifth Framework under contract No. HPRI-CT-1999-00018, the BMBF under contract 06 DA 115, GSI under contract DARIC, partly by the Spanish CICYT Agency under the projects numbers FPA2005-02379 and FPA2005-04460 as well as by the ISOLDE collaboration. ; Peer reviewed

12 páginas, 9 figuras, 3 tablas.-- et al. ; The reaction 8Li + 2H has been studied in inverse kinematics at the incident energy of 3.15 MeV/nucleon, using the REX-ISOLDE post-accelerator. The reaction channels corresponding to (d,p), (d,d), and (d,t) reactions populating ground states and low-lying excited states in 7 -9Li have been identified and the related angular distributions extracted and compared with coupled-channels, distorted-wave Born approximation (DWBA), and coupled-reaction-channels calculations. For the inelastic and (d,t) channels we find that higher order effects are very important and hence one needs to go beyond the simple DWBA to extract reliable structure information from these processes. © 2011 American Physical Society. ; The financial support of the Swedish Research Council for this work under Grant No. 2008-4158 is gratefully acknowledged, as well as support by the Lars Hierta Memorial Foundation. T. Nilsson acknowledges support through the Royal Swedish Academy of Sciences Research program by a grant from the Knut and Alice Wallenberg Foundation. This work is partially supported by the Spanish Ministerio de Ciencia e Innovacion under Projects No. FPA2006-13807- ´ C02-01, No. FPA2009-08848, No. FPA2009-07653, No. FPA2009-07387, and No. FPA2010-17142 and by the European Union Sixth Framework through RII3-EURONS (Contract No. 506065). ; Peer Reviewed

V. Pesudo et al. -- 6 pags., 10 figs., 1 tab. -- Open Access funded by Creative Commons Atribution Licence 4.0 ; This work reports on the scattering of 11Be on 197Au at energies around and below the Coulomb barrier. By experimentally identifying the elastic scattering, inelastic scattering and breakup channels, and comparing them with different calculations, valuable information on the 11Be structure and its B(E1) distribution to the continuum are obtained. On top of that, a deeper understanding of the scattering process at low energies is achieved for reactions of this kind, making these studies extendable to other loosely-bound systems like 17,19C. ; This work was supported by the Spanish Government under the projects FPA2015-64969-P, FIS2014-53448-C2-1-P, FPA2013-47327-c02-01-R, FPA2012-32443, FIS2013-41994-P and Consolider CPAN CSD2007-00042; the EUROCORES project EUI-2009-04162; the European Unions Horizon 2020 research and innovation program under grant agreement No 654002; the Helmholtz Association (HGT) through the Nuclear Astrophysics Virtual Institute (VH-VI-417); ATI Sistemas; The Natural Sciences and Engineering Research Council of Canada; The Canada Foundation for Innovation; and the British Columbia Knowledge Development Fund. TRIUMF receives federal funding via a contribution agreement through the National Research Council of Canada. OSK acknowledges support from the Villum Foundation. ; Peer Reviewed

In this work, we present our magnetron sputtering based methodology to produce amorphous silicon coatings with closed porosity, as a strategy to fabricate solid helium targets, in the form of supported or self-supported thin films, for nuclear reactions. We show how by changing the He working pressure it is possible to obtain highly porous homogeneous structures incorporating different He amounts. These porous coatings (a- Si:He) are very reproducible from run to run, and the high He amount incorporated makes them excellent candidates for solid He targets. The possibility of producing self-supported films is illustrated here, and its potential use in inverse kinematics experiments with radioactive beams is shown through the dispersion in forward geometry of a stable 6Li beam. Also the elastic scattering cross-sections for proton from helium were determined using an a-Si:He coating. The results agree well with the ones reported in the literature. These two examples validate our coatings as good candidates to be used as solid He targets in nuclear reactions. The stability of He inside the coatings, fundamental for its use as solid He targets, was investigated, both over time and after irradiation. The coatings proved to be very stable, and the amount of He inside the pores remains unaltered at least 2 years after deposition and after high irradiation fluence (5 × 1017 particles/cm2; with a dose rate of 5 × 1012 particles/(cm2 s)). ; Ministerio de Economía y Competitividad FPA2013-47327-C2-1-R, MAT2015-69035- REDC ; Consejo Superior de Investigaciones Científicas 201460E018 ; European Union CT-REGPOT-2011-285895

New experimental results for the elastic scattering of 6 He on 64Zn at incident energies of 15.0 and 18.0 MeV and 4 He at 17.5 MeV along with results already published at 10.0 and 13.6 MeV, are presented. Elastic and α experimental cross sections are compared with coupled-reaction-channel, continuum-discretized coupledchannel, and DWBA inclusive-breakup models. The large yield of α particles observed at all measured energies can be explained by considering a nonelastic breakup mechanism. ; This work was partially supported by the Spanish Ministerio de Economía y Competitividad and FEDER funds (Projects No. FIS2014-53448-C2-1-P, No. FIS2017-88410-P, and No. FPA2016-77689-C2-1-R) and by the European Union's Horizon 2020 research and innovation program under Grant Agreement No. 654002. ; Peer reviewed

New experimental results for the elastic scattering of He6 on Zn64 at incident energies of 15.0 and 18.0 MeV and He4 at 17.5 MeV along with results already published at 10.0 and 13.6 MeV, are presented. Elastic and α experimental cross sections are compared with coupled-reaction-channel, continuum-discretized coupled-channel, and DWBA inclusive-breakup models. The large yield of α particles observed at all measured energies can be explained by considering a nonelastic breakup mechanism. ; Spanish Ministerio de Economía y Competitividad and FEDER funds (FIS2014-53448-C2-1-P, FIS2017-88410P, FPA2016-77689-C2-1-R) ; European Union's Horizon 2020 654002

The one-neutron transfer reaction 9Li + 2H → 8Li + t has been investigated in an inverse kinematics experiment by bombarding a deuterated polypropylene target with a 2.36 MeV/u 9Li beam from the post-accelerator REX-ISOLDE at CERN. Excitation energies in 8Li as well as angular distributions of the tritons were obtained and spectroscopic factors deduced ; European Union Fifth Framework HPRI-CT-1999-00018 ; Comisión Interministerial de Ciencia y Tecnología FPA2002-04181-c04-02

Part of a collection: Focus Point on Small and Medium and Particle Accelerator Facilities in Europe ; The Centro Nacional de Aceleradores is a user-oriented accelerator facility in Seville, Spain. Its main facilities are a 3 MV tandem accelerator, an 18 MeV proton Cyclotron, a tandetron used for AMS, a compact accelerator used for radiocarbon measurements, a Co irradiator and a PET/CT scanner. The technical specifications and research applications of these facilities are described. A neutron beam line associated to a charged pulsed beam in the tandem allows for time of flight measurements which determine the neutron energy. The use of an adequate stripper gas in the AMS tandetron permits to measure heavy radionuclides with very low detection levels, allowing to perform environmental studies using these radionuclides as tracers. The use of the microbeam in the tandem accelerator allows to apply the ion beam-induced current technique to investigate the spectroscopic properties and radiation hardness of different semiconductor detectors. ; Also the funding made available for infrastructures through the ICTS program of the Spanish ministry of science, making use of FEDER funds from the European Union. The continuous support of CNA patrons, the University of Seville, the Junta de Andalucía and CSIC is acknowledged. Private funds, through contracts with companies and institutions, such as Curium, Alter technologies, and the andalusian health service (SAS), made possible to maintain contracts of key personnel. We acknowledge the funding of projects by the European Union, H2020-847594, H2020-654002, H2020-847552, H2020-847594 , by the Spanish ministry of science RTI2018-098117-B-C21, RTC-2017-6369-3, EQC2018-004193-P, EQC2018-004095-P, EQC2018-004166-P, PGC2018-094546-B-I00, and by the Junta de Andalucía FEDER progrem US-1261006, US-1263369, P18-RT-1900.

The experimental study of the fusion of light neutron-rich nucleus 8He with 206Pb is reported in this work. A fusion stack of 206Pb targets has been used for this study. The most prominent evaporation residue (210Po), which has half-life of 138 days and decays by alpha emission, is populated in the reaction. Radiochemical analysis technique is used to extract the yield of this evaporation residue. ; Ministerio de Ciencia e Innovavión FPA2007-63074 ; European Union 212692

The 9Li + 2H reaction has been investigated at 2.36 MeV/u at the REX-ISOLDE facility. In this Letter we focus on the 10Li + p channel which potentially holds spectroscopic information on the unbound nucleus 10Li. The experimental excitation energy spectrum and angular distribution are compared with CCBA calculations. These calculations clearly support the existence of a low-lying (s) virtual state, with a (negative) scattering length of the order as ∼ 13 - 24 fm and a p1 / 2 resonance with an energy of Er ≃ 0.38 MeV and a width of Γ ≃ 0.2 MeV. ; European Union Fifth Framework HPRI-CT-1999-00018 ; Comisión Interministerial de Investigaciones Científicas FPA2005-02379 y FPA2005-04460