| 1. |
- Svensson, C. E., et al.
(author)
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Decay Out of the Doubly Magic Superdeformed Band in the N=Z Nucleus 60Zn
- 1999
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In: Physical Review Letters. - 1079-7114. ; 82:17, s. 3400-3403
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Journal article (peer-reviewed)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. |
- Gellanki, Jnaneswari, et al.
(author)
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Characterization of Superdeformed Bands in 62Zn
- 2009
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 80:5
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Journal article (peer-reviewed)abstract
- Combined data from four fusion-evaporation reaction experiments were utilized to investigate deformed and superdeformed structures in Zn-62(30)32. Combination of the Gammasphere gamma-ray spectrometer and ancillary particle detection systems allowed for the connection of rotational bands to well-known, low-lying excited states in Zn-62, as well as spectroscopy of discrete high-spin states reaching excitation energies of E-x=42.5 MeV. Four well- or superdeformed bands in Zn-62 are characterized and described by means of cranked Nilsson-Strutinsky calculations.
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| 3. |
- Svensson, C. E., et al.
(author)
-
Collective rotational motion in the N=Z nucleus 36Ar
- 2001
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In: Nuclear Physics A. - 0375-9474. ; 682:1-4, s. 1-11
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Journal article (peer-reviewed)abstract
- A superdeformed rotational band has been identified in the N = Z nucleus 36Ar, firmly linked to known low-spin states, and observed to its high-spin termination at Iπ = 16+. Lifetime measurements by the Doppler shift attenuation method establish a large low-spin deformation (β2 ≈ 0.46) and a decrease in the collectivity as the band approaches termination. Comparisons with cranked Nilsson-Strutinsky and large-scale spherical shell model calculations lead to a consistent description of the band based on a configuration in which four particles are promoted to the pf shell. With two major shells active for both protons and neutrons, yet a valence space dimension small enough to be approached from the shell model perspective, this band offers an excellent opportunity to investigate the microscopic structure of collective rotational motion in nuclei.
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| 4. |
- Svensson, C. E., et al.
(author)
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Smooth Termination of Rotational Bands in 62Zn: Evidence for a Loss of Collectivity
- 1998
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In: Physical Review Letters. - 1079-7114. ; 80:12, s. 2558-2561
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Journal article (peer-reviewed)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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| 5. |
- Svensson, C. E., et al.
(author)
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Superdeformation in the N = z Nucleus 36Ar : Experimental, deformed mean field, and spherical shell model descriptions
- 2000
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In: Physical Review Letters. - 0031-9007. ; 85:13, s. 2693-2696
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Journal article (peer-reviewed)abstract
- A superdeformed rotational band has been identified in 36Ar, linked to known low-spin states, and observed to its high-spin termination at Iπ = 16+. Cranked Nilsson-Strutinsky and spherical shell model calculations assign the band to a configuration in which four pf-shell orbitals are occupied, leading to a low-spin deformation β2 ≈ 0.45. Two major shells are active for both protons and neutrons, yet the valence space remains small enough to be confronted with the shell model. This band thus provides an ideal case to study the microscopic structure of collective rotational motion.
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| 6. |
- Ward, D., et al.
(author)
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Band Structure of 68Ge
- 2001
-
In: Physical Review C (Nuclear Physics). - 0556-2813. ; 63:1
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Journal article (peer-reviewed)abstract
- The nucleus Ge-68 has been studied by gamma-ray spectroscopy following its population at high spin in the reaction Ca-40(S-32,4p) Ge-68. The reaction channel was selected with the Microball array and gamma rays were detected with the Gammasphere array. The level scheme is very complex, reflecting the many different, and presumably mixed, excitation modes in this nucleus. Nevertheless, there appear to be some simplifications in the spin range above 18 (h) over bar where we have identified a superdeformed band and several terminating bands. The results are compared with a cranked Nilsson-Strutinsky model without pairing.
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| 7. |
- Fischer, S. M., et al.
(author)
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Alignment delays in the N = Z nuclei Kr-72, Sr-76, and Zr-80
- 2001
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In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 8713:13
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Journal article (peer-reviewed)abstract
- The ground state rotational bands of the N = Z nuclei Kr-72, Sr-76, and Zr-80 have been extended into the angular momentum region where rotation alignment of particles is normally expected. By measuring the moments of inertia of these bands we have observed a consistent increase in the rotational frequency required to start pair breaking, when compared to neighboring nuclei. Kr-72 shows the most marked effect. It has been widely suggested that these delayed alignments arise from np-pairing correlations. However, alignment frequencies are very sensitive to shape degrees of freedom and normal pairing, so the new experimental observations are still open to interpretation.
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| 8. |
- Kelsall, N. S., et al.
(author)
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Testing mean-field models near the N=Z line : gamma-ray spectroscopy of the T-z=1/2 nucleus Kr-73
- 2002
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In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 65:4
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Journal article (peer-reviewed)abstract
- Excited states in the N=Z+1 nucleus Kr-73 have been investigated using the Ca-40(Ar-36,2pn) and Ca-40(Ca-40,alpha2pn) reactions at 145 and 160 MeV, respectively. gamma rays were detected using the Gammasphere array and events were recorded in coincidence with charged-particle and neutron detectors. The three previously observed bands were extended to high spin, and a new unfavored positive-parity band has been observed. The alignment characteristics and decay properties of the bands are all consistent with large-deformation prolate rotation, with no clear evidence for oblate bands or shape coexistence. This is quite different from neighboring Kr-72,Kr-74, indicating a strong shape-stabilizing role for the valence neutron. The experimental results are compared to extended total Routhian surface, cranked Nilsson Strutinsky, and cranked relativistic mean-field calculations. The results suggest that the paired calculations lack some important physics. Neutron-proton correlations may be the missing ingredient. There is also evidence for an unusual band crossing in the negative-parity bands, which may indicate the presence of T=0 pairing correlations. At high spin all the models can reproduce the experimental data.
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| 9. |
- Lipoglavsek, M., et al.
(author)
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First Observation of Excitation Across the 100Sn Core
- 2001
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In: Nuclear Physics, Section A. - 0375-9474. ; 682, s. 399-403
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Journal article (peer-reviewed)abstract
- Excited states of nuclei near the doubly-magic nucleus Sn-100 were studied with the Ni-58+Cr-50 reaction. The experimental setup consisted of the GAMMASPHERE array augmented with light charged-particle and neutron detectors. Excited states were identified for the first time in the proton emitting nucleus Sb-105. Excitations across the N=Z=50 doubly closed shell were observed in Cd-99 and In-101. Some results of large-scale shell-model calculations are discussed.
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| 10. |
- Pfohl, J., et al.
(author)
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Highly deformed rotational structures in 136Pm
- 2000
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In: Physical Review C - Nuclear Physics. - 0556-2813. ; 62:3, s. 313041-313045
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Journal article (peer-reviewed)abstract
- Four highly deformed structures in the odd-odd nucleus 13661Pm75 were observed via the 105Pd(35Cl,2p2n) reaction at 180 and 173 MeV using the GAMMASPHERE γ-ray spectrometer and the Microball charged-particle detector array. Quadrupole moment measurements were performed on all of the bands. In contrast to lighter odd-Ζ Pm and Pr nuclei, bands based on the g9/2[404]9/2 proton orbital were not observed. Instead, the four observed sequences are assigned as a coupling of an i13/2 neutron with the low-Ω h11/2 and mixed d5/2g7/2 orbitals. Comparisons with neighboring highly deformed structures are discussed and cranked Nilsson-Strutinsky calculations for 136Pm are presented.
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