| 11. |
- Knudsen, H. H., et al.
(author)
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Beta-decay of 13O
- 2005
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In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 72:4, s. 044312-
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Journal article (peer-reviewed)abstract
- 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.
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| 12. |
- Mach, Henryk, et al.
(author)
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The single-particle and collective features in the nuclei just above Sn-132
- 2007
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In: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 38:4, s. 1213-1218
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Journal article (peer-reviewed)abstract
- The Advanced Time Delayed method has been used to measure the lifetimes of excited states in the exotic nuclei Sb-134, Sb-135 and Te-136 populated in the beta decay of Sn-134, Sn-135 and Sn-136, respectively. High purity Sn beams were extracted at the ISOLDE separator using a novel production technique utilizing the molecular SnS+ beams to isolate Sn from contaminating other fission products. Among the new results we have identified the 1/2(+) state in Sb-135 and its E2 transition to the lower-lying 5/2(+) state was found to be surprisingly collective. This measurement represents also one of the first applications of the LaBr3 scintillator to ultra fast timing.
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| 13. |
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| 14. |
- Boutami, R., et al.
(author)
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Nuclear structure of Ac-231
- 2008
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In: Nuclear Physics A. - : Elsevier BV. - 0375-9474 .- 1873-1554. ; 811:3-4, s. 244-275
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Journal article (peer-reviewed)abstract
- The low-energy structure of Ac-231 has been investigated by means of gamma ray spectroscopy following the beta(-) decay of Ra-231. Multipolarities of 28 transitions have been established by measuring conversion electrons with a MINI-ORANGE electron spectrometer. The decay scheme of Ra-231 -> Ac-231 has been constructed for the first time. The Advanced Time Delayed beta gamma gamma(t) method has been used to measure the half-lives of five levels. The moderately fast B(EI) transition rates derived suggest that the octupole effects., albeit weak, are still present in this exotic nucleus.
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| 15. |
- 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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| 16. |
- Diget, C. A., et al.
(author)
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Breakup channels for C-12 triple-alpha continuum states
- 2009
-
In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 80:3
-
Journal article (peer-reviewed)abstract
- The triple-alpha-particle breakup of states in the triple-alpha continuum of C-12 has been investigated by way of coincident detection of all three alpha particles of the breakup. The states have been fed in the beta decay of N-12 and B-12, and the alpha particles measured using a setup that covers all of the triple-alpha phase space. Contributions from the breakup through the Be-8(0(+)) ground state as well as other channels-interpreted as breakup through excited energies in Be-8-have been identified. Spins and parities of C-12 triple-alpha continuum states are deduced from the measured phase-space distributions for breakup through Be-8 above the ground state by comparison to a fully symmetrized sequential R-matrix description of the breakup. At around 10 MeV in C-12, the breakup is found to be dominated by 0(+) strength breaking up through the ghost of the Be-8(0(+)) ground state with L = 0 angular momentum between the first emitted alpha particle and the intermediate Be-8 nucleus. For C-12 energies above the 12.7 MeV 1(+) state, however, L = 2 breakup of a C-12 2(+) state through the Be-8(2(+)) excited state dominates. Furthermore, the possibility of a 2(+) excited state in the 9-12 MeV region of C-12 is investigated.
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| 17. |
- Hyldegaard, S., et al.
(author)
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Branching ratios in the beta decays of N-12 and B-12
- 2009
-
In: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 80:4
-
Journal article (peer-reviewed)abstract
- Absolute branching ratios to unbound states in C-12 populated in the beta decays of N-12 and B-12 are reported. Clean sources of N-12 and B-12 were obtained using the isotope separation on-line (ISOL) method. The relative branching ratios to the different populated states were extracted using single-alpha as well as complete kinematics triple-alpha spectra. These two largely independent methods give consistent results. Absolute normalization is achieved via the precisely known absolute branching ratio to the bound 4.44 MeV state in C-12. The extracted branching ratios to the unbound states are a factor of three more precise than previous measurements. Branching ratios in the decay of Na-20 are also extracted and used to check the results.
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| 18. |
- 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
-
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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| 19. |
- Madurga, M., et al.
(author)
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Evidence of a new state in Be-11 observed in the Li-11 beta-decay
- 2009
-
In: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 677:5, s. 255-259
-
Journal article (peer-reviewed)abstract
- Coincidences between charged particles emitted in the beta-decay of Li-11 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 Be-11 states participating in the decay. In particular, the contribution of a previously unobserved state at 16.3 MeV in Be-11 has been identified selecting the alpha + He-7 -> alpha + He-6 + n channel. The angular correlations between the alpha particle and the center of mass of the He-6 + n system favors spin and parity assignment of 3/2(-) for this state as well as for the previously known state at 18 MeV. (C) 2009 Elsevier B.V. All rights reserved.
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| 20. |
- Alcorta, M., et al.
(author)
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Nuclear Structure of C-12 from Break-up Studies in Complete Kinematics
- 2009
-
In: AIP Conference Proceedings. - : AIP. - 1551-7616 .- 0094-243X. - 9780735407022 ; 1165, s. 27-30 461
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Conference paper (peer-reviewed)abstract
- A complete kinematics study of the B-10(He-3,p alpha alpha alpha) and B-11(He-3,d alpha alpha alpha) reactions has been performed to study the multi-particle break-up of C-12 resonances above the triple-alpha threshold. Four-particle coincidence detection gives us complete information on the direction and energy of the individual alpha particles from the decay of C-12, allowing us to extract new information on the structure of C-12 which we shall present in this contribution. We have observed gamma de-excitation of the T=1 15.11 MeV resonance using charged particle detectors, and have constructed Dalitz plots of the individual resonances in C-12 using the complete kinematics information of the alpha particles which come from their break-up.
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