| 1. |
- Sanchez-Vega, M., et al.
(författare)
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Studies of quadrupole collectivity in the γ -soft 106Ru
- 2008
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Ingår i: European Physical Journal A. - 1434-6001 .- 1434-601X. ; 35:2, s. 159-165
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Tidskriftsartikel (refereegranskat)abstract
- Various alternative models were used to describe the structure of 106Ru . For example, the General Collective Model (GCM) predicts shape-coexistence for 106Ru with a spherical and a triaxial minimum and strongly mixed structures, while in the IBA-2 calculations, where 106Ru was considered as transitional from vibrational U(5) to γ -soft O(6) , no need was found to include the shape-coexisting configurations. In order to provide additional constraints on the model interpretations, we have applied the Advanced Time-Delayed (ATD) βγγ(t) method to measure the level lifetimes of the excited levels in 106Ru . The new results include the half-lives of T 1/2 = 183(3) ps and 7.5(30)ps for the 2+ 1 and 2+ 2 states, respectively.
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| 2. |
- Mach, H., et al.
(författare)
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Application of ultra-fast timing techniques to the study of exotic and weakly produced nuclei
- 2005
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Ingår i: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 31:10, s. S1421-S1426
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Tidskriftsartikel (refereegranskat)abstract
- Ultra-fast time-delayed techniques have been recently applied in a number of studies where exotic nuclei were identified using advanced selection techniques. These include large Compton-suppressed Ge arrays, in-flight separators or recoil separators. Some of the new results are discussed in this presentation. Besides the results for Mg-32 and Pd-96, they include the first determination of the half-life of the 8(+) state in Ge-80, T-1/2 = 2.95(6) ns, and significantly more precise results for Mn-51 (3680 keV level) and V-48 (421 keV level), T-1/2 = 1760(40) ps and T-1/2.
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| 3. |
- Smith, D. L., et al.
(författare)
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Lifetime measurements of the negative-parity 7(-) and 8(-) states in Cd-122
- 2008
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 77:1, s. 014309-
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Tidskriftsartikel (refereegranskat)abstract
- The Advanced Time-Delayed beta gamma gamma(t) method was used to measure lifetimes of selected high-spin states in Cd-122 populated from beta(-) decay of the J(pi)=(9(-)) isomer in Ag-122. From the gamma gamma coincidences, a new energy level was established at 2616.6 keV with a suggested spin-parity assignment of 8(-). Lifetimes were determined for the high-spin states at 2616.6 and 2502.7 keV as T-1/2=1.35(29) ns and 0.24(6) ns, respectively. The transition rates for gamma rays de-exciting the 7(-) states in the N=74 isotones of Cd-122, Sn-124, and Te-126 were found to be very similar.
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| 4. |
- Sanchez-Vega, M., et al.
(författare)
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Studies of quadrupole collectivity in the γ -soft 106Ru
- 2008
-
Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 35:2, s. 159-165
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Tidskriftsartikel (refereegranskat)abstract
- Various alternative models were used to describe the structure of Ru-106. For example, the General Collective Model (GCM) predicts shape-coexistence for Ru-106 with a spherical and a triaxial minimum and strongly mixed structures, while in the IBA-2 calculations, where Ru-106 was considered as transitional from vibrational U(5) to gamma -soft O(6) , no need was found to include the shape-coexisting configurations. In order to provide additional constraints on the model interpretations, we have applied the Advanced Time-Delayed (ATD) beta gamma gamma(t) method to measure the level lifetimes of the excited levels in Ru-106 . The new results include the half-lives of T-1/2 = 183(3) ps and 7.5(30)ps for the 2(1)(+) and 2(1)(+) states, respectively.
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| 5. |
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| 6. |
- Caamano, M, et al.
(författare)
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Isomers in neutron-rich A approximate to 190 nuclides from Pb-208 fragmentation
- 2005
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 23:2, s. 201-215
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Tidskriftsartikel (refereegranskat)abstract
- Relativistic projectile fragmentation of Pb-208 has been used to produce isomers in neutron-rich, A approximate to 190 nuclides. A forward-focusing spectrometer provided ion-by-ion mass and charge identification. The detection of gamma-rays emitted by stopped ions has led to the assignment of isomers in Ta-188, W-190, Re-192, Re-193, Os-195, Ir-197, Ir-198, Pt-200, Pt-201, Pt-202 and Au-203, with half-lives ranging from approximately 10 ns to 1 ms. Tentative isomer information has been found also for Er-174, Er-175, Hf-185, Re-191, Re-194 and Ir-199. In most cases, time-correlated, singles gamma-ray events provided the first spectroscopic data on excited states for each nuclide. In Pt-200 and Pt-201. the assignments are supported by gamma-gamma coincidences. Isomeric ratios provide additional information, such as half-life and transition energy constraints in particular cases. The level structures of the platinum isotopes are discussed, and comparisons are made with isomer systematics.
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| 7. |
- Mach, H., et al.
(författare)
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New structure information on Mg-30, Mg-31 and Mg-32
- 2005
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 25, s. 105-109
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Konferensbidrag (refereegranskat)abstract
- The fast timing beta gamma gamma(t) method was applied to investigate the level lifetimes in Mg-30,Mg-31,Mg-32. Levels in Mg have been populated in beta and beta-delayed neutron emission of Na, at the ISOLDE facility. From the gamma gamma coincidences a number of new states have been identified and new level schemes were constructed for 30 31,32 Mg. The following preliminary half lives have been determined: T-1/2 = 3.9(4) ns for the 1789 keV state in Mg-30, T-1/2 = 133(8) ps and 10.5(8) us for the 221 keV and 461 keV states in Mg-31, respectively, and T1/2 = 16(4) ps for the 885 keV level in 32Mg. The 1789 keV level was established as a candidate for the intruder 0(+) configuration in Mg-30 with a possible strong E0 branch to the ground state.
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| 8. |
- Mach, Henryk, et al.
(författare)
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The single-particle and collective features in the nuclei just above Sn-132
- 2007
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Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 38:4, s. 1213-1218
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Tidskriftsartikel (refereegranskat)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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| 9. |
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| 10. |
- Ruchowska, E., et al.
(författare)
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Nuclear structure of Th-229
- 2006
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Ingår i: Physical Review C. Nuclear Physics. - : American Physical Society. - 0556-2813 .- 1089-490X. ; 73:4
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Tidskriftsartikel (refereegranskat)abstract
- Lifetimes of excited states in Th-229, populated in the beta decay of Ac-229, have been measured using the advanced time-delayed beta gamma gamma(t) method. Half-lives of 14 states have been determined including 11 of them for the first time. Twenty-seven new gamma lines have been introduced into the beta-decay scheme of Ac-229 based on results of gamma gamma coincidence measurements. Reduced transition probabilities have been determined for more than 70 gamma transitions in Th-229. Average parallel to D-0 parallel to values of 0.029(1), 0.077(3), and 0.024(5) e fm have been deduced for the lowest K-pi=1/2(+/-),3/2(+/-), and 5/2(+/-) parity partner bands, respectively. Excited states in Th-229 and experimental transition rates have been interpreted within the quasiparticle-plus-phonon model. The half-life of the 3.5-eV, 3/2(+) isomeric state is predicted to be about 10 h. Potential energy surfaces on the (beta(2),beta(3)) plane for the lowest single quasiparticle configurations in Th-229 have been calculated using the Strutinsky method.
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| 11. |
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