| 1. |
- Andreoiu, Corina, et al.
(author)
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Evolution of Shapes in 59Cu
- 2002
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In: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 14:3, s. 317-348
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Journal article (peer-reviewed)abstract
- High-spin states in Cu-59 were populated using the fusion-evaporation reaction Si-28 + Ca-40 at a beam energy of 122 MeV. The Gammasphere Ge-detector array in conjunction with the 4pi charged-particle detector array Microball allowed for the detection of gamma-rays in coincidence with evaporated light particles. The resulting extensive high-spin decay scheme of Cu-59 is presented, which comprises more than 320 gamma-ray transitions connecting about 150 excited states. Their spins and parities have been assigned via directional correlations of gamma-rays emitted from oriented states. Average quadrupole moments of rotational bands have been determined from the analysis of residual Doppler shifts. Shell model calculations in the fp shell are invoked to study some of the low-spin states, while the experimental characteristics of the rotational bands are analyzed in the configuration-dependent cranked Nilsson-Strutinsky (CNS) approach.
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| 2. |
- Andreoiu, Corina, et al.
(author)
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First Identification of Excited States in 59Zn
- 2002
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In: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 15, s. 459-462
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Journal article (peer-reviewed)abstract
- Excited states in 59Zn were observed for the first time following the fusion-evaporation reaction 24Mg + 40Ca at a beam energy of 60 MeV. The GASP array in conjunction with the ISIS Silicon ball and the NeutronRing allowed for the detection of n-rays in coincidence with evaporated light particles. The mirror symmetry of 59Zn and 59Cu is discussed.
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| 3. |
- Blazhev, A., et al.
(author)
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Observation of a core-excited E4 isomer in Cd-98
- 2004
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In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 69
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Journal article (peer-reviewed)abstract
- A core-excited I-pi=(12(+)) spin-gap isomer was identified in Cd-98 in an experiment at EUROBALL IV. It was found to feed the known I-pi=(8(+)) seniority isomer by an E4 transition. Half-lives of T-1/2=0.23 ((+4)(-3)) mus and 0.17 ((+6)(-4)) mus were measured for the two states at E-x=6635 keV and 2428 keV, respectively. From the excitation energy of the core-excited isomer a Sn-100 shell gap of 6.46(15) MeV is inferred. The measured E4 and E2 strengths, Sn-100 core excitations and the origin of empirical polarization charges are discussed in the framework of large-scale shell model calculations. An E2 polarization charge for protons of deltae(pi)
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| 4. |
- du Rietz, Rickard, et al.
(author)
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Effective Charges in the fp Shell
- 2004
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In: Physical Review Letters. - 1079-7114. ; 93:22
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Journal article (peer-reviewed)abstract
- Following the heavy-ion fusion-evaporation reaction S-32+Mg-24 at 95 MeV beam energy the lifetimes of analogue states in the T-z=+/-1/2 A=51 mirror nuclei Fe-51 and Mn-51 have been measured using the Cologne plunger device coupled to the GASP gamma-ray spectrometer. The deduced B(E2;27/2(-)-->23/2(-)) values afford a unique opportunity to probe isoscalar and isovector polarization charges and to derive effective proton and neutron charges, epsilon(p) and epsilon(n), in the fp shell. A comparison between the experimental results and several different large-scale shell-model calculations yields epsilon(p)similar to1.15e and epsilon(n)similar to0.80e.
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| 5. |
- Ekman, Jörgen, et al.
(author)
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Core Excited States in the A=51 Mirror Nuclei
- 2004
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 70:5
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Journal article (peer-reviewed)abstract
- Three previously unknown high-energy gamma-ray transitions between 4.2 and 5.4 MeV were identified in the T-z=-1/2 nucleus Fe-51 following the fusion-evaporation reaction S-32(Si-28, 2alpha1n)Fe-51. These transitions represent decays of core excited states. The gamma rays were detected in the Ge detector array Gammasphere combined with the neutron detector system Neutron Shell and the charged-particle array Microball. The three transitions are related to the mirror transitions in the T-z= + 1 /2 nucleus Mn-51, and the resulting mirror-energy difference diagram is discussed with predictions from large-scale shell-model calculations.
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| 6. |
- Ekman, Jörgen, et al.
(author)
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Evidence for a 1g9/2 Rotational Band in 51Mn
- 2002
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 66:5, s. 513011-513015
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Journal article (peer-reviewed)abstract
- A terminating rotational band has been identified in Mn-51 following the Si-28(S-32,2alpha1p)Mn-51 fusion-evaporation reaction at 130 MeV beam energy. Spins and tentative positive parities of the band members are assigned based on angular distribution and correlation measurements of transitions, which connect the rotational structure with previously known yrast states. Configuration-dependent cranked Nilsson-Strutinsky calculations suggest a configuration of the band, which comprises one particle in the 1g(9/2) intruder orbit.
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| 7. |
- Ekman, Jörgen, et al.
(author)
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Gamma-ray Spectroscopy of Core-excited States in 51Mn
- 2004
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 70:1
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Journal article (peer-reviewed)abstract
- The level scheme of Mn-51 has been investigated using the Si-28(S-32 2alpha1p)Mn-51 fusion-evaporation reaction at 125 MeV beam energy. The gamma rays were detected in the Ge-detector array Gammasphere, which was coupled to the 4pi-charged-particle detector Microball and the Neutron Shell for the coincident detection of evaporated particles. Over 100 new gamma-ray transitions connecting some 50 excited states have been identified. Most of the states are built on particle-hole excitations across the shell gaps at particle number N=Z=28. The rich experimental data allows for a 'comprehensive comparison of core-excited states with results from large-scale shell-model calculations, which are known to provide excellent predictions for the lower-lying yrast and near-yrast levels in 1f(7/2) nuclei.
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| 8. |
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| 9. |
- Ekman, Jörgen
(author)
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Mirror Nuclei - Isospin Symmetry Breaking in the Mass A=35 and A=51 Mirror Nuclei
- 2004
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Doctoral thesis (other academic/artistic)abstract
- High-spin states in the A=35 mirror nuclei 35Ar and 35Cl and A=51 mirror nuclei 51Fe and 51Mn were populated using fusion-evaporation reactions. The gamma rays were detected in the powerful Ge arrays Gammasphere and GASP, respectively, which operated in conjunction with ancillary detectors for evaporated particles. The resulting mirror energy difference diagrams of the two mirror pairs are interpreted in terms of various electromagnetic effects and possible isospin-symmetry breaking components of the nuclear force. In the A=35 mirror nuclei effects of the electromagnetic spin-orbit interaction have been discriminated for the first time. In addition, an unusual decay pattern of excited states can give direct evidence on isospin mixing. Excited states in 51Fe have been observed for the first time. In the A=51 mirror nuclei detailed isospin-symmetry studies are performed including core-excited states. This mark the first comparison of such analogue states in mirror nuclei. An extensive level scheme of the nucleus 51Mn has been constructed. It comprises approximately 50 previously unknown core excited states, which are interpreted in terms of comprehensive large shell-model calculations including electro-magnetic decay properties. In addition, a rotational band has been identified, which is interpreted using the cranked Nilsson-Strutinsky model and found to comprise a particle in the 1g9/2 intruder orbital.
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| 10. |
- Ekman, Jörgen, et al.
(author)
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The A=51 Mirror Nuclei 51Fe and 51Mn
- 2000
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In: European Physical Journal A. Hadrons and Nuclei. - 1434-6001. ; 9, s. 13-17
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Journal article (peer-reviewed)abstract
- Eighteen previously unknown gamma -ray transitions were identified in the T-z = -1/2 nucleus Fe-51 following the fusion-evaporation reaction S-32(Si-28,2 alpha 1n)Fe-51. The lever scheme reaches the fully aligned I-pi = 27/2(-) terminating state of the five holes in the f(7/2) shell. The 17/2(-) state was found to be isomeric, and the lifetime was measured to be 2.87 ns. The mirror symmetry of Fe-51 and Mn-51 is discussed, and the level scheme of Fe-51 is compared to shell-model calculations.
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