5 pags., 2 figs. -- International Symposium on Nuclear Astrophysics — Nuclei in the Cosmos — IX, June 25-30 2006, CERN, Geneva, Switzerland ; The aim of this work is to study the β-delayed multiparticle break-up of the 5/2− state in 9Be at 2.43 MeV excitation energy. This process is relevant as it has been proposed recently that this level plays a role in the α(αn,γ) 9Be reaction. This state breaks-up in 2α+n, and sequential as well as direct ("democratic") decay have previously been considered. In our work energy and direction of the two emitted α particles has been measured, while those of the neutron have been reconstructed. The sequential decay is considered using the R-matrix formalism. For the democratic decay the hyper-spherical harmonics functions are used. The different decay processes are compared with the data using the Monte-Carlo method. Our preliminary results indicate that the data is better described when democratic decay is assumed. ; This work is supported by the Spanish MEC under the project FPA2002-04181-C04-02 and the FPU program.
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
5 pages, 1 table, 3 figures.-- PACS nrs.: 23.40.Hc; 27.20.+n; 21.10.Hw.-- Printed version published Jun 29, 2009.-- ArXiv available at: http://arxiv.org/abs/0904.4212v1 ; Coincidences between charged particles emitted in the β-decay of 11Li were observed using highly segmented detectors. The breakup channels involving three particles were studied in full kinematics allowing for the reconstruction of the excitation energy of the 11Be states participating in the decay. In particular, the contribution of a previously unobserved state at 16.3 MeV in 11Be has been identified selecting the α + 7He → α + 6He + n channel. The angular correlations between the α particle and the center of mass of the 6He + n system favors spin and parity assignment of 3/2− for this state as well as for the previously known state at 18 MeV. ; This work has been supported by the Spanish Ministerio de Ciencia e Innovación (MICINN), under the projects FPA2007-62170 and CSD2007-00042, the European Union Sixth Framework through RII3-EURONS (contract No. 506065) and the Swedish Knut and Alice Wallenberg Foundation. ; Peer reviewed
7 pags., 4 figs. -- Presented at the XXXVI Mazurian Lakes Conference on Physics, Piaski, Poland, September 1–7, 2019. ; Beta decay is a primary source of information of the structure of a nucleus. An accurate measurement of the half-life of a nucleus is essential for the proper determination of the reduced Gammow-Teller transition probability B(GT). In this work, we present an experiment using a compact set-up of Si-telescope detectors to measure the half-life of the B nucleus. Three independent measurements have been analysed, obtaining the values 771.9(17) ms, 773.9(18) ms, and 770.9(27) ms. The value of the half-life obtained as the weighted averaged with the previous published measures is 771.17(94) ms which is a factor 3.2 of improvement in the uncertainty of the half-life. ; Work partially supported by the Spanish research grant FPA2015-64969-P, FPA2017-83946-C2-1-P and FPA2017-87568-P (MINECO/FEDER/EU) and the grant ENSAR2 from the H2020 program of the European Union under grant agreement No. 654002.
6 pags., 6 figs. -- 27th International Nuclear Physics Conference (INPC2019) 29 July - 2 August 2019, Glasgow, UK ; The main goal of this work is to study the structure of the highest energy states in 8Be populated following the ß+-decay and the electron capture (EC) of 8B. With this aim, two experiments were performed at ISOLDE-CERN in 2017 and 2018. The first experiment had the aim to resolve the 2+ doublet at 16.6 and 16.9 MeV, in order to study their isospin mixing. The second experiment aimed to determine a value or give an experimental upper limit to the branching ratio of the exotic EC-p decay. In this paper, we present the experimental setups and we discuss the analysis and present the preliminary results obtained so far. ; Work partially supported by the Spanish research grant FPA2015-64969-P and FPA2017-87568- P (MINECO) and the grant ENSAR2 from the H2020 program of the European Union under grant agreement No 654002.
4 pages, 2 figures.--PACS nrs.: 21.45.+v; 23.40.–s; 27.20.+n. ; Using beta decays of a clean source of N-13 produced at the IGISOL facility, we have measured the breakup of the C-12 (12.71 MeV) state into three alpha particles with a segmented particle detector setup. The high quality of the data permits solving the question of the breakup mechanism of the 12.71 MeV state, a longstanding problem in few-body nuclear physics. Among existing models, a modified sequential model fits the data best, but systematic deviations indicate that a three-body description is needed. ; This research was supported by the Academy of Finland under the Finnish Centre of Excellence Programme 2000-2005 (Project No. 44875, Nuclear and Condensed Matter Physics Programme at JYFL), by the Spanish Agency CICYT under Contract No. AEN99-1046-C02-02, and by the European Union Fifth Framework Programme ''Improving Human Potential–Access to Research Infrastructure.'' ; Peer reviewed
12 pages, 5 figures, 3 tables.-- PACS nrs.: 23.40.Hc; 27.20.+n.-- Printed version published Sep 15, 2008.-- ArXiv pre-print available at: http://arxiv.org/abs/0806.3025 ; The β-delayed charged particle emission from Li-11 has been studied with emphasis on the three-body nαHe-6 and five-body 2α3n channels from the 10.59 and 18.15 MeV states in Be-11. Monte Carlo simulations using an R-matrix formalism lead to the conclusion that the He-A resonance states play a significant role in the break-up of these states. The results exclude an earlier assumption of a phase-space description of the break-up process of the 18.15 MeV state. Evidence for extra sequential decay paths is found for both states. ; This work has been supported by the Spanish CICYT, under the projects FPA2002-04181-C04-02, FPA2005-02379 and theMEC Consolider project CSD2007-00042, the European Union Sixth Framework through RII3-EURONS (contract No. 506065) and the Swedish Knut and Alice Wallenberg Foundation. M. Madurga acknowledges the support of the Spanish MEC under the FPU program, FPU AP-2004-0002. ; Peer reviewed
5 pages, 2 tables, 3 figures.--PACS nrs.: 23.40.Hc; 27.20.+n. ; The beta decay of O-13 has been studied at the IGISOL facility of the Jyvaskyla accelerator centre (Finland). By developing a low-energy isotope-separated beam of O-13 and using a modern segmented charged-particle detector array an improved measurement of the delayed proton spectrum was possible. Protons with energy up to more than 12 MeV are measured and the corresponding log(ft) values extracted. A revised decay scheme is constructed. The connection to molecular states and the shell model is discussed. ; This work was supported by the Academy of Finland under the Finnish Centre of Excellence Programme 2000–2005 (Project No. 44875, Nuclear and Condensed Matter Physics Programme at JYFL), by the European Union Fifth Framework Programme "Improving Human Potential - Access to Research Infrastructure" contract no. HPRI-CT-1999-00044, by the Spanish CICYT Agency under Project number FPA2002-04181-C04-02, and by the EU-RI3 (Integrated Infrastructure Initiative) under contract no 506065. ; Peer reviewed
7 pags., 4 figs., 2 tabs. -- Open Access funded by Creative Commons Atribution Licence 4.0 ; The quasi-free scattering reactions C(p,2p) and C(p,pn) have been studied in inverse kinematics at beam energies of 300–400 MeV/u at the RB-LAND setup. The outgoing proton-proton and proton-neutron pairs were detected in coincidence with the reaction fragments in kinematically complete measurements. The efficiency to detect these pairs has been obtained from GEANT4 simulations which were tested using the C(p,2p) and C(p,pn) reactions. Experimental cross sections and momentum distributions have been obtained and compared to DWIA calculations based on eikonal theory. The new results reported here are combined with previously published cross sections for quasi-free scattering from oxygen and nitrogen isotopes and together they enable a systematic study of the reduction of single-particle strength compared to predictions of the shell model over a wide neutron-to-proton asymmetry range. The combined reduction factors show a weak or no dependence on isospin asymmetry, in contrast to the strong dependency reported in nucleon-removal reactions induced by nuclear targets at lower energies. However, the reduction factors for (p,2p) are found to be 'significantly smaller than for (p,pn) reactions for all investigated nuclei. ; This work was supported by the German Federal Ministry of Education and Research (BMBF projects 05P2015RDFN1 and 05P15WOFNA), through the GSI-TU Darmstadt cooperation agreement, by the State of Hesse through the LOEWE center HIC for FAIR, and the Helmholtz-Gemeinschaft through the graduate school HGS-HIRe. This work was supported by the European Union by means of the European Commission within its Seventh Framework Program (FP7) via ENSAR (Contract No. 262010), and the Spanish CICYT research grants FPA2012-32443, FPA2015-64969-07387, and FPA2015-69640-C2-1-P. This work has supported by the Swedish Research Council under contract number 621-2011-5324. C.A.B. acknowledges support from the U.S. NSF grant No. 1415656 and the U.S. DOE grant No. DE-FG02-08ER41533. Supported by the Portuguese FCT under the project PTDC/FIS/ 103902/2008.
New experimental data for dissociation of relativistic 17Ne projectiles incident on targets of lead, carbon, and polyethylene targets at GSI are presented. Special attention is paid to the excitation and decay of narrow resonant states in 17Ne. Distributions of internal energy in the 15O +p +pthree-body system have been determined together with angular and partial-energy correlations between the decay products in different energy regions. The analysis was done using existing experimental data on 17Ne and its mirror nucleus 17N. The isobaric multiplet mass equation is used for assignment of observed resonances and their spins and parities. A combination of data from the heavy and light targets yielded cross sections and transition probabilities for the Coulomb excitations of the narrow resonant states. The resulting transition probabilities provide information relevant for a better understanding of the 17Ne structure. ; This project is supported by NAVI, GSI-TU Darmstadt cooperation, HIC for FAIR, EMMI and BMBF. C.A.B. acknowledges support from the U.S. NSF Grant No. 1415655, and U.S. DOE grant No. DEFG02- 08ER41533. The work was also supported by the Spanish government grant FPA2012-32443 and the Swedish Research Council ; SI