Publications (153)159.6 Total impact
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Article: Beta Decay Of Exotic Tz = -1 And Tz = -2 Nuclei
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ABSTRACT: The half-lives of the Tz = -2, 56Zn and Tz = -1, 58Zn isotopes and other nuclei were measured in a {\beta}-decay experiment at GANIL. The energy levels populated by the 56Zn {\beta} decay were determined. The 56Zn results are compared with the results of the mirror process, the charge exchange reaction 56Fe(3He,t)56Co.01/2013; -
Article: High-resolution study of Gamow-Teller transitions in the Ti-47(He-3, t)V-47 reaction
Physical Review C 01/2013; 87(1):014321. · 3.31 Impact Factor -
Article: The population of metastable states as a probe of relativistic-energy fragmentation reactions
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ABSTRACT: Isomeric ratios have been measured for high-spin states in Po-198,200,206,208, At-208,209,210,211,Rn-210,211,212,213,214, Fr-208,211,212,213,214, Ra-210,211,212,214,215, and Ac-215 following the projectile fragmentation of a 1 A GeV U-238 beam by a Be-9 target at GSI Helmholtzzentrum für Schwerionenforschung. The fragments were separated in the fragment separator (FRS) and identified by means of energy loss and time-of-flight techniques. They were brought to rest at the centre of the RISING gamma-ray detector array and intensities of gamma rays emitted in the decay of isomeric states with half-lives between 100 ns and 40 μs and spin values up to 55/2 ℏ were used to obtain the corresponding isomeric ratios. The data are compared to theoretical isomeric ratios calculated in the framework of the abrasion–ablation model. Large experimental enhancements are obtained for high-spin isomers in comparison to expected values.Physics Letters B 01/2013; · 3.95 Impact Factor -
Conference Proceeding: b - delayed neutron emission measurements around the third r-process abundance peak
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ABSTRACT: One of the main challenges for the better understanding of nucleosynthesis in the rapid neutron capture process (r-process) concerns the enormous amount of very exotic neutron-rich nuclei involved in this kind of cataclysmic scenario, and the scarce information available about their nuclear properties. In particular, theoretical calculations in the mass region around N=126 are difficult to validate on the basis only of the experimental information available close to stability so far. Such information becomes relevant for a reliable interpretation of the third peak in the r-process abundance distribution. Present and next generation radioactive-beam facilities (RIB) will be instrumental towards the systematicmeasurement of such nuclei, for improving theoretical nuclear models, and for enhancing the accuracy of the nuclear physics input in r-process model calculations. Here we present an experiment carried out recently at Fragment Separator (FRS) at the GSI Helmholtz Center for Heavy Ion Research in Darmstadt (Germany), which allowed us to measure for the first time relevant nuclear properties of several neutron-rich isotopes in the region around 211Hg and 215Tl. Preliminary results about the identified species and their implantation statistics are reported in this contribution. The experimental setup was comprised of an array of silicon implantation detectors (SIMBA) and the BEta deLayEd Neutron detector (BELEN). The main advantage compared to previous experiments was due to an innovative self-triggered acquisition system, which allowed us to enhance the neutron detection probability when compared to conventional analogue acquisition systems. This setup has been developed in the framework of the NuSTAR (Nuclear Structure, Astrophysics and Reactions) in the DESPEC (DEcay SPECtroscopy) collaboration which will perform experiments at the future Super Fragment Separator (SuperFRS) at FAIR (Facility for Antiproton and Ion Research).XII International Symposium on Nuclei in the Cosmos, Cairns, Australia; 08/2012 -
Article: Storage ring facility at HIE-ISOLDE Technical Design Report
The European Physical Journal Special Topics 05/2012; 207:1-117. · 1.56 Impact Factor -
Article: Multiple β− decaying states in 194Re: Shape evolution in neutron-rich osmium isotopes
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ABSTRACT: β decays from heavy, neutron-rich nuclei with A∼190 have been investigated following their production via the relativistic projectile fragmentation of an E/A=1 GeV 208Pb primary beam on a ∼2.5 g/cm2 9Be target. The reaction products were separated and identified using the GSI FRagment Separator (FRS) and stopped in the RISING active stopper. γ decays were observed and correlated with these secondary ions on an event-by-event basis such that γ-ray transitions following from both internal (isomeric) and β decays were recorded. A number of discrete, β-delayed γ-ray transitions associated with β decays from 194Re to excited states in 194Os have been observed, including previously reported decays from the yrast Iπ=(6+) state. Three previously unreported γ-ray transitions with energies 194, 349, and 554 keV are also identified; these transitions are associated with decays from higher spin states in 194Os. The results of these investigations are compared with theoretical predictions from Nilsson multi-quasiparticle (MQP) calculations. Based on lifetime measurements and the observed feeding pattern to states in 194Os, it is concluded that there are three β−-decaying states in 194Re.Physical Review C 05/2012; 85(3):034301. · 3.31 Impact Factor -
Article: Preparing a journey to the east of 208Pb with ISOLTRAP: Isobaric purification at A = 209 and new masses for 211-213Fr and 211Ra
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ABSTRACT: With the Penning trap mass spectrometer ISOLTRAP, located at ISOLDE/CERN, preparatory work has been performed towards mass and decay studies on neutron-rich Hg and Tl isotopes beyond N = 126 . The properties of these isotopes are not well known because of large isobaric contamination coming mainly from surface-ionised Fr. Within the studies, production tests using several target-ion source combinations were performed. It was furthermore demonstrated around mass number A = 209 that the resolving power required to purify Fr is achievable with ISOLTRAP. In addition, masses of several isobaric contaminants, 211-213Fr and 211Ra , were determined with a three-fold improved precision. The results influence masses of more than 20 other nuclides in the 208Pb region.European Physical Journal A 04/2012; 42(3):351-359. · 2.19 Impact Factor -
Article: Pygmy dipole resonance in 208Pb
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ABSTRACT: Scattering of protons of several hundred MeV is a promising new spectroscopic tool for the study of electric dipole strength in nuclei. A case study of 208Pb shows that at very forward angles J^pi = 1- states are strongly populated via Coulomb excitation. A separation from nuclear excitation of other modes is achieved by a multipole decomposition analysis of the experimental cross sections based on theoretical angular distributions calculated within the quasiparticle-phonon model. The B(E1) transition strength distribution is extracted for excitation energies up to 9 MeV, i.e., in the region of the so-called pygmy dipole resonance (PDR). The Coulomb-nuclear interference shows sensitivity to the underlying structure of the E1 transitions, which allows for the first time an experimental extraction of the electromagnetic transition strength and the energy centroid of the PDR.03/2012; -
Conference Proceeding: The Tz = -1 -> Tz =0 beta decays and comparison with Charge Exchange reactions
AIP Conf. Proc.; 01/2012 -
Conference Proceeding: Soft spin-dipole resonances in 40Ca
Journal of Physics: Conference Series 381 (2012) 012096; 01/2012 -
Article: Multiple beta �-Decaying states in 194Re: Shape Evolutionin Neutron-Rich Osmium Isotopes
Physical Review C 01/2012; 85:034301. · 3.31 Impact Factor -
Article: Decay heat studies for nuclear energy
Hyperfine Interactions 01/2012; · 0.21 Impact Factor -
Conference Proceeding: Beta decay of exotic TZ=-1 and TZ=-2 nuclei
AIP Conference Proceedings; 01/2012 -
Article: Storage ring at HIE-ISOLDE
The European Physical Journal Special Topics 01/2012; 207:1. · 1.56 Impact Factor -
Article: Multiple beta(-) decaying states in Re-194: Shape evolution in neutron-rich osmium isotopes (vol 85, 034301, 2012)
Physical Review C 01/2012; 85:039904(E). · 3.31 Impact Factor -
Article: Multiple beta(-) decaying states in Re-194: Shape evolution in neutron-rich osmium isotopes
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ABSTRACT: beta decays from heavy, neutron-rich nuclei with A similar to 190 have been investigated following their production via the relativistic projectile fragmentation of an E/A = 1 GeV Pb-208 primary beam on a similar to 2.5 g/cm(2) Be-9 target. The reaction products were separated and identified using the GSI FRagment Separator (FRS) and stopped in the RISING active stopper. gamma decays were observed and correlated with these secondary ions on an event-by-event basis such that gamma-ray transitions following from both internal (isomeric) and beta decays were recorded. A number of discrete, beta-delayed gamma-ray transitions associated with beta decays from Re-194 to excited states in Os-194 have been observed, including previously reported decays from the yrast I-pi = (6(+)) state. Three previously unreported gamma-ray transitions with energies 194, 349, and 554 keV are also identified; these transitions are associated with decays from higher spin states in Os-194. The results of these investigations are compared with theoretical predictions from Nilsson multi-quasiparticle (MQP) calculations. Based on lifetime measurements and the observed feeding pattern to states in Os-194, it is concluded that there are three beta(-)-decaying states in Re-194.Physical Review C 01/2012; 85:034301. · 3.31 Impact Factor -
Article: AGATA - Advanced Gamma Tracking Array
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ABSTRACT: The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation gamma-ray spectrometer. AGATA is based on the technique of gamma-ray energy tracking in electrically segmented high-purity germanium crystals. This technique requires the accurate determination of the energy, time and position of every interaction as a gamma ray deposits its energy within the detector volume. Reconstruction of the full interaction path results in a detector with very high efficiency and excellent spectral response. The realization of gamma-ray tracking and AGATA is a result of many technical advances. These include the development of encapsulated highly-segmented germanium detectors assembled in a triple cluster detector cryostat, an electronics system with fast digital sampling and a data acquisition system to process the data at a high rate. The full characterization of the crystals was measured and compared with detector-response simulations. This enabled pulse-shape analysis algorithms, to extract energy, time and position, to be employed. In addition, tracking algorithms for event reconstruction were developed. The first phase of AGATA is now complete and operational in its first physics campaign. In the future AGATA will be moved between laboratories in Europe and operated in a series of campaigns to take advantage of the different beams and facilities available to maximize its science output. The paper reviews all the achievements made in the AGATA project including all the necessary infrastructure to operate and support the spectrometer.Nuclear Instruments and Methods in Physics Research Section A Accelerators Spectrometers Detectors and Associated Equipment 11/2011; 668:26. · 1.21 Impact Factor -
Article: Complete electric dipole response and the neutron skin in 208Pb.
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ABSTRACT: A benchmark experiment on (208)Pb shows that polarized proton inelastic scattering at very forward angles including 0° is a powerful tool for high-resolution studies of electric dipole (E1) and spin magnetic dipole (M1) modes in nuclei over a broad excitation energy range to test up-to-date nuclear models. The extracted E1 polarizability leads to a neutron skin thickness r(skin) = 0.156(-0.021)(+0.025) fm in (208)Pb derived within a mean-field model [Phys. Rev. C 81, 051303 (2010)], thereby constraining the symmetry energy and its density dependence relevant to the description of neutron stars.Physical Review Letters 08/2011; 107(6):062502. · 7.37 Impact Factor -
Article: The 150Nd(3He,t) and 150Sm(t,3He) reactions with applications to ββ decay of 150Nd
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ABSTRACT: The 150Nd(3He,t) reaction at 140 MeV/u and 150Sm(t,3He) reaction at 115 MeV/u were measured, populating excited states in 150Pm. The transitions studied populate intermediate states of importance for the (neutrinoless) ββ decay of 150Nd to 150Sm. Monopole and dipole contributions to the measured excitation-energy spectra were extracted by using multipole decomposition analyses. The experimental results were compared with theoretical calculations obtained within the framework of the quasiparticle random-phase approximation, which is one of the main methods employed for estimating the half-life of the neutrinoless ββ decay (0νββ) of 150Nd. The present results thus provide useful information on the neutrino responses for evaluating the 0νββ and 2νββ matrix elements. The 2νββ matrix element calculated from the Gamow-Teller transitions through the lowest 1+ state in the intermediate nucleus is maximally about half that deduced from the half-life measured in 2νββ direct counting experiments, and at least several transitions through 1+ intermediate states in 150Pm are required to explain the 2νββ half-life. Because Gamow-Teller transitions in the 150Sm(t,3He) experiment are strongly Pauli blocked, the extraction of Gamow-Teller strengths was complicated by the excitation of the 2ℏω, ΔL=0, ΔS=1 isovector spin-flip giant monopole resonance (IVSGMR). However, the near absence of Gamow-Teller transition strength made it possible to cleanly identify this resonance, and the strength observed is consistent with the full exhaustion of the non-energy-weighted sum rule for the IVSGMR.Phys. Rev. C. 06/2011; 83(6). -
Article: Synthesis of N=127 isotones through (p,n) charge-exchange reactions induced by relativistic 208Pb projectiles
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ABSTRACT: The production cross sections of four N=127 isotones (207Hg, 206Au, 205Pt, and 204Ir) have been measured using (p,n) charge-exchange reactions, induced in collisions of a 208Pb primary beam at 1 A GeV with a Be target. These data allow one to investigate the use of a reaction mechanism to extend the limits of the chart of nuclides toward the important r-process nuclei in the region of the third peak of elemental abundance distribution.Physical Review C 05/2011; 84(1):011601(R). · 3.31 Impact Factor
Top Journals
Institutions
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1993–2012
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University of Valencia
Valencia, Valencia, Spain
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1990–2012
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Instituto de Física Corpuscular
Paterna, Valencia, Spain -
Forschungszentrum Jülich
- Institut für Kernphysik (IKP)
Düren, North Rhine-Westphalia, Germany
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2005–2011
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Osaka University
- • Research Center for Nuclear Physics
- • Department of Physics
Ōsaka-shi, Osaka-fu, Japan
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2010
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Konan University
Tokyo, Tokyo-to, Japan -
Université Libre de Bruxelles
Brussels, BRU, Belgium
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2005–2010
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University of Surrey
- Department of Physics
Guildford, ENG, United Kingdom
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2002
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The University of York
- Department of Physics
York, ENG, United Kingdom
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1986–1991
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University of Jyväskylä
- Department of Physics
Jyväskylä, Western Finland, Finland
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