| 1. |
- Svensson, C. E., et al.
(författare)
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Decay Out of the Doubly Magic Superdeformed Band in the N=Z Nucleus 60Zn
- 1999
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Ingår i: Physical Review Letters. - 1079-7114. ; 82:17, s. 3400-3403
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Tidskriftsartikel (refereegranskat)abstract
- The doubly magic superdeformed band in the N = Z nucleus Zn-60 has been identified. Linking transitions connecting this band to the yrast line provide the first spin, parity, and excitation energy measurements for superdeformed states in the A similar to 60 region. The stretched-E2 character and relatively large B(E2) values of these transitions suggest a nonstatistical decay-out process.
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| 2. |
- Svensson, C. E., et al.
(författare)
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Smooth Termination of Rotational Bands in 62Zn: Evidence for a Loss of Collectivity
- 1998
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Ingår i: Physical Review Letters. - 1079-7114. ; 80:12, s. 2558-2561
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Tidskriftsartikel (refereegranskat)abstract
- Two sets of strongly coupled rotational bands have been identified in Zn-62. These bands have been observed up to the terminating states of their respective configurations. Lifetime measurements indicate that the transition quadrupole moments in these bands decrease as termination is approached. These results establish the first terminating states of rotational bands in the A similar to 60 mass region and confirm the predicted loss of collectivity associated with smooth band termination.
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| 3. |
- Gizon, J., et al.
(författare)
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Terminating bands in the doubly odd nucleus [Formula Presented]
- 1999
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 59:2, s. 570-574
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Tidskriftsartikel (refereegranskat)abstract
- High spin states have been populated in [Formula Presented] using the reaction [Formula Presented] at 130 MeV. The γ rays have been detected with the EUROGAM2 array. The level structure of [Formula Presented] has been investigated. Several bands have been identified and established over a wide range of spin. They are interpreted using the Nilsson-Strutinsky cranking formalism and explained in terms of band terminations. Their configurations are built from the valence particles and valence holes relative to a [Formula Presented] core: [Formula Presented] protons (and [Formula Presented] proton holes) and [Formula Presented] and [Formula Presented] neutrons. After [Formula Presented] is the second heavy nucleus and the first odd-odd nucleus in which configurations in the valence space are followed from low spin up to their termination.
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| 4. |
- Mullins, S. M., et al.
(författare)
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Strong population of a superdeformed band in Eu142
- 1995
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Ingår i: Physical Review C. - 0556-2813. ; 52:1, s. 99-103
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Tidskriftsartikel (refereegranskat)abstract
- A superdeformed band has been found in Eu142. It is populated with 1.2(2)% of the total -ray intensity that decayed into Eu142 via the reaction Sn120(27Al,5n)142Eu at 152 MeV. The strength of the band is similar to that previously reported in Eu143, where the superdeformed band is populated with an intensity of 1.1(1)%. This is unexpected, since both total Routhian surface (TRS) and cranked modified oscillator (MO) calculations predict that the superdeformed band in Eu143 becomes yrast at lower spin than that in Eu142. This difference is 4Latin small letter h with stroke in the MO calculations and 8Latin small letter h with stroke in the TRS. Extrapolation of the normal-deformed yrast states in Eu143 shows, however, that a difference of 8Latin small letter h with stroke in spin corresponds to a change in the relative energy of the superdeformed and normal-deformed yrast lines of only 1 MeV.
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| 5. |
- Rudolph, Dirk, et al.
(författare)
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Shell-model Influence in the Rotational Nucleus 86Mo
- 1996
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 54:1, s. 117-124
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Mo-86 were studied by means of the fusion evaporation reaction Ni-58(S-32,2p2n) Mo-86 at 135 MeV beam energy. Charged-particle-gamma gamma and -gamma gamma gamma coincidences recorded with the early implementation of the GAMMASPHERE array and the MICROBALL charged-particle detection system were used to largely extend the level scheme of the T-tau=1 nucleus Mo-86 to a possible spin of I=24h at 13 MeV excitation energy. The excitation scheme is compared to neighboring nuclei. There is evidence for enhanced shell-model influence in the 4 quasiparticle region (I=12-16h). The observed (pi=+,alpha=0) sequence at spin I greater than or equal to 16 h appears to be associated with a triaxial collective rotational band. This interpretation is supported by calculations within the configuration-dependent shell-correction approach with the cranked Nilsson potential.
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| 6. |
- Sarantites, D. G., et al.
(författare)
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Triaxial superdeformed bands in [Formula Presented]
- 1998
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 57:1, s. 1-5
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Tidskriftsartikel (refereegranskat)abstract
- Four new superdeformed bands have been found in the nucleus [Formula Presented]. The good agreement between experiment and configuration-dependent shell correction calculations suggests that three of the bands have triaxial superdeformed shapes. Such unique features in mass [Formula Presented] superdeformed bands have been predicted, but not observed experimentally until now. A fourth band in [Formula Presented] is interesting due to a fairly constant and unusually high dynamic moment of inertia. Possible interpretations of this structure are discussed.
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| 7. |
- Svensson, C. E., et al.
(författare)
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Observation and Quadrupole Moment Measurement of the First Superdeformed Band in the A~60 Mass Region
- 1997
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Ingår i: Physical Review Letters. - 1079-7114. ; 79:7, s. 1233-1236
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Tidskriftsartikel (refereegranskat)abstract
- A high-spin rotational cascade of six gamma rays has been observed in Zn-62. The quadrupole moment of 2.7(-0.5)(+0.7) e b measured for this band corresponds to a deformation beta(2) = 0.45(-0.07)(+0.10). The properties of this band are in excellent agreement with calculations that predict high-spin superdeformed bands in Zn-62 with deformations beta(2) = 0.41-0.49. These results establish a new region of superdeformation for nuclei with neutron and proton numbers N, Z approximate to 30-32.
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| 8. |
- Devlin, M., et al.
(författare)
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Superdeformation in 68Zn: Evidence for a New, Neutron-rich Island of Superdeformation in A~70 Nuclei
- 1999
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Ingår i: Physical Review Letters. - 1079-7114. ; 82, s. 5217-5220
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Tidskriftsartikel (refereegranskat)abstract
- A superdeformed rotational structure is reported in the stable nucleus Zn-68. It has a transition quadrupole moment (Q(t)) of 2.5(-0.4)(+0.7) e b (beta(2) approximate to 0.4), as measured by the residual Doppler shift method. Theoretical calculations suggest that two different configurations are possible candidates for this band. One is built without h(11/2) neutrons, as seen in superdeformed bands in the A similar to 60 region, while the other involves one h(11/2) neutron in analogy with superdeformed bands in the A similar to 80 region. The second of these candidate configurations is preferred, thus establishing a new, neutron-rich (relative to the line of beta stability) region of superdeformation with Z similar to 30 and N similar to 38.
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| 9. |
- Lane, G. J., et al.
(författare)
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Identification of excited states in doubly odd [Formula Presented]Sb : Smooth band termination
- 1997
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 55:5, s. 2127-2131
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in [Formula Presented]Sb have been identified for the first time in a series of [Formula Presented]-spectroscopy experiments using both thin and backed targets, including neutron-fold and recoil-mass measurements to provide unambiguous channel identification. The three decoupled intruder bands observed in [Formula Presented]Sb are based upon configurations involving 2p-2h excitations across the [Formula Presented] shell gap and show the features of smooth band termination. The yrast intruder band, which has been connected to the low-spin levels, is tentatively identified up to its predicted termination at [Formula Presented]. Excellent agreement with configuration-dependent cranked Nilsson-Strutinsky calculations is obtained for the high-spin states near termination.
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| 10. |
- Afanasjev, A. V., et al.
(författare)
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Comparative study of superdeformed and highly deformed bands in the [Formula Presented] mass region
- 1999
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 59:6, s. 3166-3171
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Tidskriftsartikel (refereegranskat)abstract
- Superdeformed and highly deformed rotational bands in the [Formula Presented] mass region are studied within cranked relativistic mean field theory and the configuration-dependent cranked Nilsson-Strutinsky approach. Both approaches describe the experimental data well. Low values of the dynamic moments of inertia [Formula Presented] compared with the kinematic moments of inertia [Formula Presented] seen both in experiment and in calculations at high rotational frequencies indicate the high energy cost to build the states at high spin and reflect the limited angular momentum content in these configurations.
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| 11. |
- Afanasjev, A. V., et al.
(författare)
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The coexistence of the intruder vi13/2, superdeformed and terminating bands in the A ∼ 135 mass region
- 1996
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474. ; 608:2, s. 176-201
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Tidskriftsartikel (refereegranskat)abstract
- The configuration-dependent shell-correction approach with the cranked Nilsson potential is employed for a systematic investigation of the high-spin spectra of the nuclei in the A ∼ 135 (Z = 57-61, N = 72-78) mass region, where superdeformed bands have been observed. Main attention is paid to the coexistence of intruder νi13/2, superdeformed and terminating bands in the yrast region. Recent developments of the formalism allow the identification of the high-j orbitals in each N-shell, for example, the g9/2 orbitals in the N = 4 shell, after the diagonalization of the cranked Nilsson potential. This turns out to be quite important for the understanding of the high collectivity of the observed bands. It is shown that the equilibrium deformation of the superdeformed bands is strongly dependent on the number of the proton holes in the g9/2 orbitals. With increasing neutron number above N = 75, the intruder νi13/2 bands are calculated triaxial. Especially for Z = 57, but also for higher proton numbers, we calculate some coexistent oblate non-collective states which are yrast for specific spin values at I ≥ 40h.
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