| 1. |
- Jeppesen, H. B., et al.
(author)
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Investigation of the Li-9+H-2 -> Li-8+t reaction at REX-ISOLDE
- 2006
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 635, s. 17-17
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Journal article (peer-reviewed)abstract
- The one-neutron transfer reaction Li-9 + H-2 -> Li-8 + t has been investigated in an inverse kinematics experiment by bombarding a deuterated polypropylene target with a 2.36 MeV/u Li-9 beam from the post-accelerator REX-ISOLDE at CERN. Excitation energies in Li-8 as well as angular distributions of the tritons were obtained and spectroscopic factors deduced. (c) 2006 Elsevier B.V. All rights reserved.
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| 2. |
- Jeppesen, H. B., et al.
(author)
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Low energy reactions with radioactive ions at REX-ISOLDE - the Li-9+H-2 case
- 2005
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In: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 748, s. 374-374
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Journal article (peer-reviewed)abstract
- At the newly constructed postaccelerator REX-ISOLDE (Radioactive beam Experiment at ISOLDE) we have investigated reactions induced by a Li-9 beam incident on a deuterium target at an energy of 2.36 MeV/u. Most reaction channels were recorded. From one-neutron transfer the differential cross-section for the low lying Li-10 spectrum is found. The results from the other channels demonstrate the great applicability and many possibilities that REX-ISOLDE opens up.
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| 3. |
- Jeppesen, H. B., et al.
(author)
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Study of Li-10 via the Li-9(H-2, p) reaction at REX-ISOLDE
- 2006
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In: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 642:5-6, s. 449-454
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Journal article (peer-reviewed)abstract
- The Click to view the MathML source reaction has been investigated at 2.36 MeV/u at the REX-ISOLDE facility. In this Letter we focus on the Click to view the MathML source 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 asnot, vert, similar1324 fm and a p1/2 resonance with an energy of Ersimilar, equals0.38 MeV and a width of Γsimilar, equals0.2 MeV.
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| 4. |
- Aksyutina, Yu, et al.
(author)
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Lithium isotopes beyond the drip line
- 2008
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In: Physics Letters B. - : Elsevier BV. - 0370-2693. ; 666:5, s. 430-434
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Journal article (peer-reviewed)abstract
- The unbound isotopes 10Li, 12Li and 13Li have been observed after nucleon-knockout reactions at relativistic energies with 11Li and 14Be beams impinging on a liquid hydrogen target. The channels , and were analysed in the ALADIN-LAND setup at GSI. The 10Li data confirm earlier findings, while the 12Li and 13Li nuclei were observed for the first time. The relative-energy spectrum shows that the ground state of 12Li can be described as a virtual s-state with a scattering length of -13.7(1.6) fm. A broad energy spectrum was found for the channel. Based on the assumption that the relative-energy spectrum is dominated by a correlated background presumably stemming from initial correlations in the 14Be ground-state, evidence for a 13Li resonance at 1.47(31) MeV above the threshold with a width around 2 MeV has been found.
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| 5. |
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| 6. |
- Diget, C. A., et al.
(author)
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Properties of the C-12 10 MeV state determined through beta-decay
- 2005
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In: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 760:1-2, s. 3-18
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Journal article (peer-reviewed)abstract
- The beta-delayed triple-alpha particle decay of B-12 has been measured with a setup that favours coincidence detection. A broad state in C-12, previously reported around 10 MeV, has been seen and its properties determined through R-matrix analysis of the excitation spectrum. The spin and parity are 0(+). Interference between this state and the Hoyle state at 7.654 MeV has a marked influence on the spectrum. The coupling between the two states makes it difficult to determine the resonance energy. (c) 2005 Elsevier B.V. All rights reserved.
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| 7. |
- Fynbo, H. O. U., et al.
(author)
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Revised rates for the stellar triple-alpha process from measurement of C-12 nuclear resonances
- 2005
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687 .- 1476-4679. ; 433:7022, s. 136-139
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Journal article (peer-reviewed)abstract
- In the centres of stars where the temperature is high enough, three alpha-particles (helium nuclei) are able to combine to form C-12 because of a resonant reaction leading to a nuclear excited state(1). (Stars with masses greater than similar to0.5 times that of the Sun will at some point in their lives have a central temperature high enough for this reaction to proceed.) Although the reaction rate is of critical significance for determining elemental abundances in the Universe(1), and for determining the size of the iron core of a star just before it goes supernova(2), it has hitherto been insufficiently determined(2). Here we report a measurement of the inverse process, where a C-12 nucleus decays to three alpha-particles. We find a dominant resonance at an energy of similar to11 MeV, but do not confirm the presence of a resonance at 9.1 MeV (ref. 3). We show that interference between two resonances has important effects on our measured spectrum. Using these data, we calculate the triple-a rate for temperatures from 10(7) K to 10(10) K and find significant deviations from the standard rates(3). Our rate below similar to5 x 10(7) K is higher than the previous standard, implying that the critical amounts of carbon that catalysed hydrogen burning in the first stars are produced twice as fast as previously believed(4). At temperatures above 10(9) K, our rate is much less, which modifies predicted nucleosynthesis in supernovae(5,6).
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| 8. |
- Chulkov, L. V., et al.
(author)
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Three-body correlations in electromagnetic dissociation of Borromean nuclei: The He-6 case
- 2005
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In: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 759:1-2, s. 23-42
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Journal article (peer-reviewed)abstract
- Dissociation of He-6 on a lead target has been studied at 240 MeV/u. The four-momenta of the two neutrons in coincidence with alpha-particles have been measured and used to reconstruct the three-body energy and angular correlations in the final state. For the first time, three-body correlations were included in the analysis of the He-6 dissociation data, and compared with calculations assuming a dipole mode for the electromagnetic dissociation. In addition, the experimental data have been analyzed using a series expansion of the final transition amplitude into hyperspherical functions, showing the importance of both nn and alpha n final-state interactions. It is shown that the dissociation process is governed by a transition of one neutron from the p-shell in the 6He ground state to the s-shell in the continuum further indicating that the role of the transition through an intermediate He-5(3/2(-)) state is more important than expected. (c) 2005 Elsevier B.V. All rights reserved.
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| 9. |
- Cortina-Gil, D., et al.
(author)
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One-neutron knockout of O-23
- 2005
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In: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 25, s. 343-346
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Conference paper (peer-reviewed)abstract
- Breakup reactions were used to study the ground-state configuration of the neutron-rich isotope O-23. The O-22 fragments produced in one-nucleon removal from O-23 at 938 MeV/nucleon in a carbon target were detected in coincidence with de-exciting gamma rays, allowing to discern between 220 ground-state and excited-states contributions. From the comparison of exclusive experimental momentum distributions for the one-neutron removal channel to theoretical momentum distributions calculated in an Eikonal model for the knockout process, and spin and parity assignment of I-pi = 1/2(+) was deduced for the 230 ground state. This result solved the existent experimental discrepancy.
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| 10. |
- Prezado, Y., et al.
(author)
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Low-lying resonance states in the Be-9 continuum
- 2005
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In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 618:1-4, s. 43-50
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Journal article (peer-reviewed)abstract
- Excited states in Be-9 from 2 to 9 MeV are studied via beta delayed particle emission from Li-9. The broad overlapping particle unbound states are investigated using an extension of an experimental method developed for dealing with three-body decays of broad isolated levels. The results confirm the existence of a broad state at 5 MeV, with a width of 2 MeV. Angular correlations are used for firm spin determinations for this and other levels.
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