| 1. |
- Axelsson, A, et al.
(författare)
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An investigation of pairing correlations in diabatic configurations at high spin and large deformation: applications to the description of SD bands in Eu-143
- 2002
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Ingår i: Nuclear Physics, Section A. - 0375-9474. ; 708:3-4, s. 245-276
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Tidskriftsartikel (refereegranskat)abstract
- The HFB cranked shell model is applied in an investigation of the selfconsistent pairing properties of the superdeformed (SD) bands in Eu-143. Results from a fully pairing and deformation selfconsistent mesh calculation of the properties of the most intense SD band in 143Eu are presented, as well as pairing selfconsistent calculations done at a fixed deformation close to the SD minimum for an excited SD configuration. The calculations are compared to unpaired calculations and to published experimental data. Fully diabatic configurations are studied and total energy surfaces are constructed for fixed values of the angular momentum. Other issues addressed include the development of the particle number distribution in the HFB wave function up to very high frequency, the consequences of using a fixed Fermi energy in high-spin calculations and the effects of the number of excited quasiparticles on the pairing properties of the superdeformed nucleus. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 2. |
- 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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| 3. |
- Lipoglavsek, M., et al.
(författare)
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First Observation of Excitation Across the 100Sn Core
- 2001
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Ingår i: Nuclear Physics, Section A. - 0375-9474. ; 682, s. 399-403
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Tidskriftsartikel (refereegranskat)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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| 4. |
- Rudolph, Dirk, et al.
(författare)
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The Lifetime of the Proton-decaying 8915 keV State in 58Cu
- 2001
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Ingår i: Nuclear Physics, Section A. - 0375-9474. ; 694, s. 132-146
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Tidskriftsartikel (refereegranskat)abstract
- Energy correlations between gamma -ray transitions and the prompt proton decay line in Cu-58 were studied by means of the fusion-evaporation reaction Ca-40(Mg-24,1 alpha 1p1n) using the EUROBALL spectrometer coupled to ancillary detector devices. A lifetime of 0.06 < tau < 0.58 ps for the 8915 keV proton-decaying state in Cu-58 is deduced. (C) 2001 Elsevier Science B.V. All rights reserved.
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| 5. |
- Sohler, D, et al.
(författare)
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Neutron Excitations Across the N=50 Shell Gap in 102In
- 2002
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Ingår i: Nuclear Physics, Section A. - : Elsevier. - 0375-9474 .- 1873-1554. ; 708:3-4, s. 181-189
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Tidskriftsartikel (refereegranskat)abstract
- The structure of In-102 has been investigated by in-beam gamma-spectroscopic methods. Knowledge on the excited states of this nucleus has significantly been extended. Three cascades of transitions were observed to exceed the spin-energy domain spanned by the pig(9/2)(-1)v(d(5/2),g(7/2))(3) configurations. The new high spin states at similar to 4 MeV excitation energy could be assigned to the pig(9/2)(-1)v(d(5/2), g(7/2))(2)h (11/2) configuration, while at least those at 4.733, 5.192 and 5.853 MeV most likely arise from the vg(9/2) --> vd(5/2), g(7/2) one-particle-one-hole excitation across the N = 50 shell closure.
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| 6. |
- 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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| 7. |
- Cederwall, Bo, et al.
(författare)
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HIGH-SPIN STATES IN BA-121 AND DEFORMATION-DEPENDENT ALIGNMENTS
- 1991
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Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 529:2, s. 410-428
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Tidskriftsartikel (refereegranskat)abstract
- The high-spin structure of 121Ba has been investigated by in-beam gamma-ray spectroscopic techniques. Rotational bands based on the h11/2, g7/2 and tentatively d5/2 quasineutron configurations have been established. The alignments of h11/2 protons and neutrons are identified at HBAR-omega-c = 0.35-0.40 MeV in the h11/2 and g7/2 bands whereas an alignment occurs at HBAR-omega-c = 0.29 MeV in the (tentatively) d5/2 band. B(M1)/B(E2) ratios were extracted and contributed to the configuration assignments. The results are interpreted within the cranked mean-field approach.
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| 8. |
- Cederwall, Bo, et al.
(författare)
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SIGNATURE INVERSION IN CS-120 - EVIDENCE FOR A RESIDUAL PN INTERACTION
- 1992
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Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 542:3, s. 454-478
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states have been observed in the odd-odd isotope 120Cs in S-32-induced reactions. The previously known band is extended to higher spin and several new bands are identified. Band-head configurations have been inferred by comparing the band properties with known bands in the odd nuclei 121Cs and 121Ba. A remarkable signature inversion is observed in the pi-h11/2 x nu-h11/2 band. The experimental data are compared with calculations made within the total routhian surface model and the two-particle plus triaxial rotor model. It is concluded that a significant residual pn interaction rather than triaxiality is responsible for the signature inversion phenomenon in the pi-h11/2 x nu-h11/2 band of 120Cs.(~)[GRAPHICS]
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| 9. |
- FAHLANDER, C, et al.
(författare)
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IN-BEAM SPECTROSCOPY OF TE-110
- 1994
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Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 577:3-4, s. 773-785
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Tidskriftsartikel (refereegranskat)abstract
- The neutron-deficient nucleus Te-110 has been investigated by in-beam spectroscopic methods using the NORDBALL multi-detector array. Except for the energy of one level observed in alpha-decay, excited states in Te-110 were previously unknown. The level scheme constructed from gamma gamma-coincidence relationships is presented with tentative spin assignments up to I-pi = 21(-). Above spin 8(+) the yrast states have negative parity. They are most likely the members of a band predominantly based on the nu(h(11/2)g(7/2)) two-quasiparticle configuration. A band crossing is observed at I-pi approximate to 17(-). It is suggested to be caused by the alignment of two h(11/2) neutrons. The cranked shell model correctly predicts the spin alignment, but fails to reproduce the observed band crossing frequency, possibly because of octupole effects.
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| 10. |
- JERRESTAM, D, et al.
(författare)
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COLLECTIVE EXCITATIONS IN CD-106
- 1994
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Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474 .- 1873-1554. ; 571:2, s. 393-412
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Tidskriftsartikel (refereegranskat)abstract
- High Spin states in 106Cd were populated by the reactions Zr-94(O-17, 5n) and Ge(S-32, 4n) at 80 MeV and at 148 MeV, respectively. The gamma-decay was studied by gamma-spectroscopic methods using the Nordball multi-detector army. Protons and alpha-particles were detected in particle detector system, thus selecting the neutron channel. The experiment included gamma-ray yields, gammagamma-coincidences and gamma-ray angular relation measurements. Collective bands extending up to spin 26+, 20- and 21-, have been observed in 106Cd. A new lifetime Of 11(-3)+6 ns for the 16+ state at 7118.7 keV has been found. Both total Routhian surfaces and spin diabatic surfaces have been calculated and used for assigning quasiparticle configurations to the bands. The (+, 0) band is assigned as a nuh11/2(2) configuration below I = 16+ and at higher spins suggested to be built on a pig9/2(2)nuh11/2(2) configuration. The large hindrance observed for the decay from the 16+ state supports the latter assignment. With the alignment of the nuh11/12(2) pair the deformation is predicted to change from (epsilon2,gamma) = (0.13,-2-degrees) to (0.17, 4-degrees). The configuration of the negative parity bands is assigned as either a nuh11/2(1)d5/2(1) or a nuh11/2(1)(g7/2xd5/2)1, With (epsilon2, gamma) = (0.14,9-degrees.
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