| 1. |
- Al-Dahan, N., et al.
(författare)
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Isomeric States In 208Hg And 209Tl Populated In Fragmentation Of 238U
- 2009
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Ingår i: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 40:3, s. 871-874
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Tidskriftsartikel (refereegranskat)abstract
- The nuclear structure of neutron-rich N > 126 nuclei has been investigated following their production via relativistic projectile fragmentation of a E/A = 1 GeV U-238 beam on a Be target. The preliminary analysis indicates the presence of previously unreported isomeric states in the N = 128 isotones Hg-208 and Tl-209.
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| 2. |
- Doornenbal, P., et al.
(författare)
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RISING: Gamma‐ray Spectroscopy with Radioactive Beams at GSI
- 2007
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Ingår i: AIP Conference Proceedings. - : AIP. - 0094-243X. - 9780735413283 ; 891, s. 99-107
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Konferensbidrag (refereegranskat)abstract
- The Rare Isotope Spectroscopic INvestigation at GSI (RISING) project is a major pan‐European collaboration. Its physics aims are the studies of exotic nuclear matter with abnormal proton‐to‐neutron ratios compared with naturally occurring isotopes. RISING combines the FRagment Separator (FRS) which allows relativistic energies and projectile fragmentation reactions with EUROBALL Ge Cluster detectors for γ spectroscopic research. The RISING setup can be used in two different configurations. Either the nuclei of interest are investigated after being stopped or the heavy ions hit a secondary target at relativistic energies and the thereby occurring excitations are studied. For the latter case, MINIBALL Ge detectors and the HECTOR array are used in addition. Example achievements of the Fast Beam setup are presented and compared to various shell model calculations, while for the Stopped Beam setup initial results are shown.
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| 3. |
- Mason, P, et al.
(författare)
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Octupole signatures in Ba-124,Ba-125
- 2005
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Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 31:10, s. S1729-S1733
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Tidskriftsartikel (refereegranskat)abstract
- The gamma decay of the nuclei Ba-121,Ba-125 has been investigated with the EUROBALL array, using the reaction Ni-64+Ni-64 at E-beam = 255 and 261 MeV. Six new E1 transitions have been found in the nucleus Ba-125, suggesting a significant role of octupole correlations in the origin of its parity doublets. The J(pi) = 3(-) level of the nucleus Ba-124 has been identified for the first time. Its excitation energy is in very good agreement with a prediction based on a microscopic model including octupole interactions.
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| 4. |
- Yadav, R. B., et al.
(författare)
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Identification of triaxial strongly deformed bands in Hf-168
- 2008
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 78:4
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Tidskriftsartikel (refereegranskat)abstract
- Possible decay pathways associated with three candidates for triaxial strongly deformed (TSD) bands in Hf-168 have been investigated. The spin and excitation energy of the strongest band, TSD1, were determined approximately based on gamma-ray coincidence relationships. Discrete links were established for the second band. The overall agreement between the observed properties of the bands and cranking calculations using the ULTIMATE CRANKER code provides strong support for an interpretation where band TSD1 is associated with a TSD minimum, (epsilon(2),gamma)similar to(0.43,20(degrees)), involving the pi(i(13/2))(2) and the nu(j(15/2)) high-j orbitals. This constitutes the first identification of a TSD band in Hf isotopes, which has been long-predicted by theoretical studies. The second band is understood as being associated with a near-prolate shape and a deformation enhanced with respect to the normal deformed bands. It is proposed to be built on the pi(i(13/2)h(9/2))circle times nu(i(13/2))(2) configuration.
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| 5. |
- Al-Dahan, N., et al.
(författare)
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Nuclear Structure "Southeast" of 208Pb: Isomeric states in 208Hg and 209Tl
- 2009
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 80:6
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Tidskriftsartikel (refereegranskat)abstract
- The nuclear structure of neutron-rich N>126 nuclei has been investigated following their production via relativistic projectile fragmentation of a E/A=1 GeV U-238 beam. Metastable states in the N=128 isotones Hg-208 and Tl-209 have been identified. Delayed gamma-ray transitions are interpreted as arising from the decay of I-pi=(8(+)) and (17/2(+)) isomers, respectively. The data allow for the so far most comprehensive verification of the shell-model approach in the region determined by magic numbers Z < 82 and N>126.
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| 6. |
- Al-Dahan, N., et al.
(författare)
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Structure of N≥126 Nuclei Produced in Fragmentation of 238U
- 2009
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Ingår i: Proceedings of the 13th International Symposium on Capture Gamma‐Ray Spectroscopy and Related Topics. - : AIP. - 0094-243X. ; 1090, s. 145-148
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Konferensbidrag (refereegranskat)abstract
- The nuclear structure of neutron-rich N≥126 nuclei have been investigated following their production via relativistic projectile fragmentation of a E/A=l GeV 238U beam on a Be target. The cocktail of secondary beam products were separated and identified using the GSI FRagment Separator (FRS). The nuclei of interest were implanted in a high-granularity active stopper detector set-up consisting of 6 double sided silicon strip detectors. The associated gamma-ray transitions were detected with the RISING array, consisting of 15 Euroball cluster Ge-detectors. Time-correlated gamma decays from individually identified nuclear species have been recorded, allowing the clean identification of isomeric decays.
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| 7. |
- Al-Khatib, A, et al.
(författare)
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Transition to non-collective states at high spin in Xe-124
- 2008
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 36:1, s. 21-29
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in Xe-124 were populated in the reaction Se-82(Ca-48, 6n) Xe-124 and gamma-ray coincidence relationships were measured with the Gammasphere spectrometer. Two new bands are observed and several of the previously known bands are extended in the high-as well as in the low-spin region. Two irregular high-spin structures are also added. The irregularities are a fingerprint of a transition from collective to non-collective behaviour. Configuration assignments to the new structures are proposed on the basis of systematics and by comparing experimental properties with calculations within the framework of the cranking model.
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| 8. |
- Bacelar, A. M. Denis, et al.
(författare)
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Angular Momentum Population In Fragmentation Reactions
- 2009
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Ingår i: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 40:3, s. 889-892
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Tidskriftsartikel (refereegranskat)abstract
- Neutron-deficient nuclei with N = 126 have been populated following projectile fragmentation of a U-238 beam with energy 1 GeV/A. The decay of several previously reported isomers has been measured. This will allow us to calculate high-spin isomeric ratios and compare them with model calculations to allow a better understanding of the reaction mechanism.
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| 9. |
- Hammond, G, et al.
(författare)
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Spectroscopy of T=3/2 Mirror Nuclei via Two-step Fragmentation using RISING
- 2005
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Ingår i: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 36:4, s. 1253-1257
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Tidskriftsartikel (refereegranskat)abstract
- Two two-step fragmentation reactions were performed using RISING to populate excited states in A approximate to 50 mirror nuclei near to the proton-drip line, in order to test isospin symmetry. The experiments were designed to observe gamma decays of excited states in the mirror nuclei Ni-53(28)25/Mn-53(25)28, which have a large value of total isospin (T = 3/2). In the continuing off-line analysis, gamma transitions have been observed in Ni-54 indicating that two-step fragmentation is a successful technique for spectroscopic investigations of proton-rich nuclear systems in this mass region.
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| 10. |
- Lozeva, R. L., et al.
(författare)
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New sub-us Isomers in 125Sn, 127Sn, 129Sn and Isomer Systematics of 124-130Sn
- 2008
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 77:6
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Tidskriftsartikel (refereegranskat)abstract
- New sub-mu s isomers have been observed in the neutron-rich Sn isotopes. Sn-125,Sn-127,Sn-129 nuclei have been produced in a relativistic fission reaction of U-238 on a Be-9 target at 750 A.MeV and by the fragmentation of Xe-136 at 600 A.MeV populating high-spin yrast states. In addition to the already known mu s isomers, three new ones with sub-mu s half-lives have been observed. These yrast isomers are the high-spin members of the nu(d(3/2)(-1)h(11/2)(-2)) and nu h(11/2)(-n), seniority v = 3 multiplets leading to isomeric (23/2(+)) and (27/2(-)) states, respectively. Added to the already known 19/2(+)mu s isomers in this region the current work completes the systematic information of neutron-hole excitations toward the filling of the last h(11/2) orbital at N = 82. The results are discussed in the framework of state-of-the-art shell-model calculations using realistic interactions.
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