| 1. |
- Ertoprak, Aysegul, et al.
(författare)
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Evidence for octupole collectivity in 172Pt
- 2020
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Ingår i: European Physical Journal A. - : Springer. - 1434-6001 .- 1434-601X. ; 56:2
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in the extremely neutron-deficient nucleus 172Pt were populated via 96Ru(78Kr,2p) and 92Mo(83Kr,3n) reactions. The level scheme has been extended up to an excitation energy of ~ 5 MeV and tentative spin-parity assignments up to Iπ = 18+. Linear polarization and angular distribution measurements were used to determine the electromagnetic E1 character of the dipole transitions connecting the positive-parity ground-state band with an excited side-band, firmly establishing it as a negative-parity band. The lowest member of this negative-parity structure was firmly assigned spin-parity 3-. In addition, we observed an E3 transition from this 3- state to the ground state, providing direct evidence for octupole collectivity in 172Pt. Large-scale shell model (LSSM) and total Routhian surface (TRS) calculations have been performed, supporting the interpretation of the 3- state as a collective octupole-vibrational state.
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| 2. |
- Hadinia, Baharak, et al.
(författare)
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Identification of gamma rays from Au-172 and alpha decays of Au-172, Ir-168, and Re-164
- 2009
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 80:6, s. 064310-
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Tidskriftsartikel (refereegranskat)abstract
- The very neutron deficient odd-odd nucleus Au-172 was studied in reactions of 342 and 348 MeV Kr-78 beams with an isotopically enriched Ru-96 target. The alpha decays previously reported for Au-172 were confirmed and the decay chain extended down to Tm-152 through the discovery of a new alpha-decaying state in Re-164 [E-alpha=5623(10) keV; t(1/2)=864(-110)(+150) ms; b(alpha)=3(1)%]. Fine structure in these alpha decays of Au-172 and Ir-168 were identified. A new alpha-decaying state was also observed and assigned as the ground state in Au-172 [E-alpha=6762(10) keV; t(1/2)=22(-5)(+6) ms]. This decay chain was also correlated down to Tm-152 through previously reported alpha decays. Prompt gamma rays from excited states in Au-172 have been identified using the recoil-decay tagging technique. The partial level scheme constructed for Au-172 indicates that it has an irregular structure. Possible configurations of the alpha-decaying states in Au-172 are discussed in terms of the systematics of nuclei in this region and total Routhian surface calculations.
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| 3. |
- Hadinia, B., et al.
(författare)
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IN-BEAM gamma-RAY SPECTROSCOPY ABOVE THE HIGH-SPIN ISOMERIC STATE IN Lu-155
- 2013
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Ingår i: CAPTURE GAMMA-RAY SPECTROSCOPY AND RELATED TOPICS. - : WORLD SCIENTIFIC PUBL CO PTE LTD. ; , s. 139-144
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Konferensbidrag (refereegranskat)abstract
- Excited states in Lu-155 have been studied at the Accelerator Laboratory of the University of Jyvaskyla in Finland. The Lu-155 nuclei were populated using the reaction of Ni-58 on (102)pd at a beam energy of 280 MeV. The nuclei of interest were selected using the RITU gas filled recoil separator and the prompt gamma rays belonging to 155Lu were identified using the recoil-decay tagging technique. The gamma-ray transitions de-exciting the excited states above the high-spin isomeric a-decaying state in Lu-155 have been identified. A gamma-ray coincidence analysis shows that the previously reported level scheme for Lu-155 should be revised.
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| 4. |
- Juutinen, S, et al.
(författare)
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Coexistence of collective and quasiparticle structures in Sn-106 and Sn-108
- 1997
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Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 617:1, s. 74-90
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Tidskriftsartikel (refereegranskat)abstract
- New levels in the neutron deficient nuclei Sn-106 and Sn-108 have been investigated by using the NORDBALL detector array combined with charged particle and neutron detectors. The excited structures are discussed in terms of collectivity and the shell model. The excitations are interpreted to be based on d5/2, g7/2 and h(11/2) both for protons and neutrons and g(9/2) for protons. The systematical behaviour of the specific states in the Sn isotopes is studied in the mass range of A = 106-118.
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| 5. |
- Juutinen, S, et al.
(författare)
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Coexistence of collective and quasiparticle structures in Sn-106 and Sn-108
- 1997
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Ingår i: NUCLEAR PHYSICS A. - : ELSEVIER SCIENCE BV. - 0375-9474. ; 617:1, s. 74-90
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- New levels in the neutron deficient nuclei Sn-106 and Sn-108 have been investigated by using the NORDBALL detector array combined with charged particle and neutron detectors. The excited structures are discussed in terms of collectivity and the shell mode
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| 6. |
- Kownacki, J, et al.
(författare)
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High-spin studies of the neutron deficient nuclei In-103, In-105, In-107, and In-109
- 1997
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Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 627:2, s. 239-258
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states of the isotopes 103,105,107,109In have been investigated using in-beam γ-ray spectroscopic methods. Results from three different experiments are presented. Targets of 54Fe, 50Cr, and 92Mo were bombarded by a 270 and 261 MeV 58Ni beam and by a 95 MeV 19F beam, respectively. Reaction channel separation was achieved with a charged-particle detector array and in the first two experiments also with a 1π neutron detector system. As a result of these experiments the level schemes of 103,105,107,109In were significantly extended. Excited states of these odd-A indium isotopes are discussed within the framework of the nuclear shell model and the hole-core coupling scheme. The systematics of excited states of light odd-A indium isotopes is also discussed.
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| 7. |
- Bianco, L., et al.
(författare)
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Discovery of W-157 and Os-161
- 2010
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Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 690:1, s. 15-18
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Tidskriftsartikel (refereegranskat)abstract
- The nuclides W-157 and Os-161 have been discovered ill reactions of Ni-58 ion beams with a Cd-106 target. The Os-161 alpha-decay energy and half-life were 6890 +/- 12 keV and 640 +/- 60 mu s. The daughter W-157 nuclei beta-decayed with a half-life of 275 +/- 40 ms, populating both low-lying alpha-decaying states in Ta-157, which is consistent with a 7/2(-) ground state in W-157. Fine structure observed in the alpha decay of Os-161 places the lowest excited state in W-157 with 1(pi) = 9/2(-) at 318 +/- 30 key. The branching ratio of 5.5(-2.2)(+3.1)% indicates that Os-161 also has a 7/2(-) ground state. Shell-model calculations analysing the effects of monopole shifts and a tensor force on the relative energies of 2f(7/2) and 1h(9/2) neutron states in N = 83 isotones are presented. (C) 2010 Elsevier B.V. All rights reserved.
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| 8. |
- CEDERKALL, J, et al.
(författare)
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1ST OBSERVATION OF EXCITED-STATES IN SB-108
- 1995
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Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 581:1, s. 189-204
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Tidskriftsartikel (refereegranskat)abstract
- A spectroscopic study of Sb-108 has been carried out as a part of a larger experiment where in total twenty-nine different residual nuclei were identified. This study gives the first information on excited levels in this nucleus. A low-lying two-quasi-particle multiplet together with some of the higher lying levels are discussed within the framework of the nuclear shell model. A rotational, strongly coupled, band is identified as, most likely, being built on the deformed pig9/2(-1) nuh11/2 configuration in accordance with total routhian surface calculations. Tentative spins and parities are presented as well as B(M1)/B(E2) ratios for some of the transitions in the strongly coupled band.
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| 9. |
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| 10. |
- Cederwall, Bo, et al.
(författare)
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Evidence for a spin-aligned neutron-proton paired phase from the level structure of 92Pd
- 2011
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 469:7328, s. 68-71
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Tidskriftsartikel (refereegranskat)abstract
- Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work(1) that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing(2-6), in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus Pd-92. Gamma rays emitted following the Ni-58(Ar-36,2n)Pd-92 fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution c-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction(2-6). We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling(7,8)) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis.
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