| 1. |
- Testov, D. A., et al.
(författare)
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Octupole correlations near Te 110
- 2021
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Ingår i: Physical Review C. - : American Physical Society. - 2469-9985 .- 2469-9993. ; 103:4
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Tidskriftsartikel (refereegranskat)abstract
- The lifetime of the 2+ and 9-, 11-, 13-, 15- states in the neutron-deficient Te110 was measured for the first time using the recoil distance Doppler shift technique. The reported value of the reduced transition probability B(E2;0g.s+→2+)=4.3(8)×103e2fm4 supports the systematic for even-mass Te isotopes and was interpreted in the framework of the large-scale shell model and cranked shell model calculations. The measured reduced transition probabilities in the negative-parity yrast band revealed the upward trend towards the high spins. The enhanced collectivity is discussed in terms of the tilted axis cranking approach and the symmetry configuration mixing method with the Gogny D1S interaction.
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| 2. |
- Kelsall, N. S., et al.
(författare)
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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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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 65:4
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Tidskriftsartikel (refereegranskat)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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| 3. |
- De Angelis, G., et al.
(författare)
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Collective Excitations in the Vicinity of N=Z
- 1999. - 1 SUPPL. 1
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Ingår i: Proceedings INPC 1998. - 0375-9474. ; 654, s. 659-662
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Konferensbidrag (refereegranskat)abstract
- In our contribution to the INPC98 conference we reported on the experimental investigation of high spin collective states in medium and heavy mass N≈Z nuclei at LNL. The main purpose is to set light on the role of the proton-neutron interaction in the collective behavior of the nucleus. In medium mass N=Z nuclei, in contrast with the stable nuclei, valence protons and neutrons occupy the same orbitals and one may expect a reinforcement of neutron-proton T=0 (np) pairing correlations[1]. In this interesting subject, the medium mass N=Z=36 72Kr has been studied and completely reported in [2]. In this proceedings we will concentrate in unpublished results concerning the onset of collectivity on nearly spherical nuclei in the 100Sn region. In nuclei with Z=50 and Z=49 dipole bands have been found indicating the presence of "Magnetic Rotation" [3].
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| 4. |
- Hartley, D. J., et al.
(författare)
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Wobbling mode in Ta-167
- 2009
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 80:4
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Tidskriftsartikel (refereegranskat)abstract
- The collective wobbling mode, the strongest signature for the rotation of a triaxial nucleus, has previously been seen only in a few Lu isotopes in spite of extensive searches in nearby isotopes. A sequence of transitions in the N = 94 Ta-167 nucleus exhibiting features similar to those attributed to the wobbling bands in the Lu nuclei has now been found. This band feeds into the pi i(13/2) band at a relative energy similar to that seen in the established wobbling bands and its dynamic moment of inertia and alignment properties are nearly identical to the i(13/2) structure over a significant frequency range. Given these characteristics, it is likely that the wobbling mode has been observed for the first time in a nucleus other than Lu, making this collective motion a more general phenomenon.
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| 5. |
- Lee, I Y, et al.
(författare)
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Study of neutron-rich nuclei using deep-inelastic reactions
- 1997
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 56:2, s. 753-759
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Tidskriftsartikel (refereegranskat)abstract
- We have used the Ca-48+Yb-176 reaction to study the population of high-spin states in neutron-rich nuclei by deep-inelastic reactions. Using Gammasphere, we observed gamma transitions from nuclei several neutrons richer than the target. Yrast states with spin up to 20 were populated in this reaction. High-spin states in Yb-175,Yb-177,Yb-178 were observed. In this region of reduced pairing, a reference based on experimental data was used to derive experimental Routhians. Systematics of experimental Routhians in neutron-rich Yb nuclei compare well with cranked shell-model calculations.
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| 6. |
- Leguillon, R., et al.
(författare)
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High-spin spectroscopy of Nd-140
- 2013
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 88:1
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Tidskriftsartikel (refereegranskat)abstract
- The population of the high-spin states in Nd-140 was investigated using the reaction Zr-96(Ca-48,4n). The results from two experiments, one with the EUROBALL array and one with the JUROGAM II + RITU + GREAT setup employing the recoil decay tagging technique, have been combined to develop a very detailed level scheme for Nd-140. Twelve bands of quadrupole transitions and eleven bands of dipole transitions were identified and their connections to low-lying states were established. Calculations using the cranked Nilsson-Strutinsky and the tilted axis cranking models were used to interpret the observed structures. The overall good agreement between the experimental results and the calculations assuming a triaxial shape of the nucleus strongly support the existence of a stable triaxial shape at high spins in this mass region.
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| 7. |
- O'Leary, C. D., et al.
(författare)
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Evidence for isovector neutron-proton pairing from high-spin states in N = Z 74Rb
- 2003
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 67:2, s. 213011-213015
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in the odd-odd N = Z nucleus 3774Rb37 were studied using the 40Ca(40Ca,αnp) reaction. A previously observed odd-spin T = 0 band has been extended to Iπ = (31+) and an even-spin T = 0 band has been observed for the first time to Iπ = (22+); both have a π(g9/2)⊗ν(g9/2) structure. A strongly coupled low-spin T = 0, K = 3 band has been interpreted as being based upon a π[312]3/2 ⊗ ν[312]3/2 configuration. Cranked relativistic Hartree-Bogoliubov calculations, which are corrected for the t = 1 np-pair field by restoring isospin symmetry, reproduce the observed spectrum. These new results provide evidence for the existence of an isovector pair field that contains a neutron-proton component with the proper strength for ensuring isospin conservation.
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| 8. |
- Zerrouki, T., et al.
(författare)
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Shape evolution and magnetic rotation in Nd-141
- 2015
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 51:4
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Tidskriftsartikel (refereegranskat)abstract
- The high-spin states in Nd-141 were investigated using the Zr-96(Ca-48, 3n) reaction and the EU-ROBALL array. The level scheme has been extended up to an excitation energy of around 16MeV and spin 81/2. Two new bands of dipole transitions and three bands presumably of quadrupole transitions were identified and their connections to low-lying states were established. Cranked Nilsson-Strutinsky and tilted axis cranking calculations are combined in the interpretation of the observed dipole bands. The high-spin bands with assigned quadrupole transitions are interpreted as triaxial bands, while the dipole bands appear in the calculations to exhibit a shape evolution from low-deformation triaxial to spherical shape. They can be classified as magnetic rotation, with transition probabilities that show the characteristic decrease with angular momentum caused by the shears mechanism.
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| 9. |
- Baldsiefen, G, et al.
(författare)
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Shears bands in Pb-193
- 1996
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 54:3, s. 1106-1116
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Tidskriftsartikel (refereegranskat)abstract
- Four bands of enhanced dipole transitions, with weak crossovers, have been observed in Pb-195. Three of these bands are connected to the spherical levels. in addition, the spherical level scheme has been extended. The nuclear spectroscopy was done with the early implementation of GAMMASPHERE and HERA arrays of Get detectors. The nucleus Pb-193 was populated in the Yb-174(Mg-24,5n) reaction at beam energies of 129, 131, and 134 MeV. The experimental results are compared to tilted-axis cranking calculations. The systematical behavior of the dipole bands in the heavier odd-A Pb isotopes, Pb-195,Pb-197,Pb-199,Pb-201, is also discussed.
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| 10. |
- Plettner, C., et al.
(författare)
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Very high rotational frequencies and band termination in 73Br
- 2000
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Ingår i: Physical Review C - Nuclear Physics. - 0556-2813. ; 62:1, s. 143131-143136
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Tidskriftsartikel (refereegranskat)abstract
- Rotational bands in 73Br have been investigated up to spins of I = 65/2 using the EUROBALL III spectrometer. One of the negative-parity bands displays the highest rotational frequency ℏω= 1.85 MeV reported to date in nuclei with A ≥ 25. At high frequencies, the experimental J(2) dynamic moment of inertia for all bands decreases to very low values, J(2) ≤ 10ℏ2 MeV-1. The bands are described in the configuration-dependent cranked Nilsson-Strutinsky model. The calculations indicate that one of the negative-parity bands is observed up to its terminating single-particle state at spin 63/2. This result establishes the first band termination in the A ≈ 70 mass region.
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