| 1. |
- Klimkiewicz, A., et al.
(författare)
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Pygmy Dipole Strength in Exotic Nuclei and the Equation of State
- 2009
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Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1165, s. 181-184 461
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Konferensbidrag (refereegranskat)abstract
- A concentration of dipole strength at energies below the giant dipole resonance was observed in neutron-rich nuclei around Sn-132 in an experiment using the FRS-LAND setup. This so-called "pygmy" dipole strength can be related to the parameters of the symmetry energy and to the neutron skin thickness on the grounds of a relativistic quasiparticle random-phase approximation. Using this ansatz and the experimental findings for Sn-130 and 132 Sri, we derive a value of the symmetry energy pressure of (p) over bar (0) = 2.2 +/- 0.5 MeV/fm(3). Neutron skin thicknesses of R-n-R-p = 0.23 +/- 0.03 fm and 0.24 +/- 0.03 fm for Sn-130 and Sn-132, respectively, have been determined. Preliminary results on Ni-68 from a similar experiment using an improved setup indicate an enhanced cross section at low energies, while the results for Ni-58 are in accordance with results from photoabsorption measurements.
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| 2. |
- Mahata, K., et al.
(författare)
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Study of dipole excitations and the single particle structure of neutron rich Ni isotopes
- 2008
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Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1012, s. 389-391 453
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Konferensbidrag (refereegranskat)abstract
- An experiment was performed using the FRS-LAND setup at GSI to study the dipole strength distributions above neutron separation threshold for neutron-rich Ni isotopes. Measurements, using the same experimental setup, were also carried out to extract single particle occupancies via knockout reactions to investigate the structure and magicity of the neutron-rich Ni isotopes. The status of the data analysis and preliminary results are presented.
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| 3. |
- Hornillos, M. B. G., et al.
(författare)
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gamma-ray spectroscopy approaching the limits of existence of atomic nuclei : A study of the excited states of Pt-168 and Pt-169
- 2009
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 79:6
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in the N=90 and N=91 Pt nuclei have been investigated using the JUROGAM and GREAT spectrometers in conjunction with the RITU gas-filled separator. These nuclei were populated via the reactions Mo-92(Kr-78,2n) and Mo-94(Kr-78,3n) at 335 and 348 MeV, respectively. The recoil-decay tagging technique has been used to correlate prompt gamma radiation with the characteristic alpha decays of Pt-168 and Pt-169. A gamma-gamma analysis has allowed a level scheme for Pt-168 to be reported for the first time and the level scheme for Pt-169 to be extended. The excitation energies of the proposed positive-parity yrast states of Pt-168 are compared with calculations based on the interacting boson model and found to be in excellent agreement. These data show a continuation of the trend toward vibrational nuclei as the N=82 shell gap is approached. In addition, new excited states constituting two decay paths have been discovered in Pt-169. .
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| 4. |
- Kröll, T., et al.
(författare)
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Transfer Reactions on Neutron-rich Nuclei at REX-ISOLDE
- 2009
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Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1165, s. 363-368 461
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Konferensbidrag (refereegranskat)abstract
- We report on one- and two-neutron transfer reactions to study the single-particle properties of nuclei at the border of the "island of inversion". The (d,p)- and (t,p)-reactions in inverse kinematics on the neutron-rich isotope Mg-30, delivered as radioactive beam by the REX-ISOLDE facility, have been investigated. The outgoing protons have been detected and identified by a newly built array of Si detectors. The gamma-decay of excited states has been detected in coincidence by the MINIBALL array. First results for Mg-31 and from the search for the second, spherical, 0(+) state in Mg-32 are presented.
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| 5. |
- O'Donnell, D., et al.
(författare)
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First observation of excited states in Hg-175(95)
- 2009
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 79:5, s. 051304-
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Tidskriftsartikel (refereegranskat)abstract
- Excited states of the neutron-deficient nucleus Hg-175, populated using fusion-evaporation reactions, are reported for the first time. The spin and parity of the ground state has been determined to be I-pi=7/2(-) through measurements of the alpha decay to the daughter nucleus Pt-171. A structure based on an isomeric state [T-1/2=0.34(3) mu s] with I-pi=13/2(+) and its decay path to the ground state have been established. The observed structures are interpreted in terms of single-particle configurations, and the trends of coexisting shapes in neighboring nuclei are discussed.
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| 6. |
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| 7. |
- Chatterjee, A., et al.
(författare)
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1n and 2n transfer with the borromean nucleus He-6 near the Coulomb barrier
- 2008
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 101:3, s. 032701-
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Tidskriftsartikel (refereegranskat)abstract
- Angular distributions for In and 2n transfer are reported for the He-6 + Cu-65 system at E-lab = 22.6 MeV. For the first time, triple coincidences between a particles, neutrons, and characteristic gamma rays from the targetlike residues were used to separate the contributions arising from In and 2n transfer. The differential cross sections for these channels, elastic scattering, and fusion were analyzed using a coupled reaction channels approach. The large measured ratio of the 2n-to-1n cross section and the strong influence of 2n transfer on other channels indicate that the dineutron configuration of He-6 plays a dominant role in the reaction mechanism.
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