| 1. |
- Andreoiu, Corina, et al.
(författare)
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Doorway States in the Gamma Decay-out of the Yrast Superdeformed Band in 59Cu
- 2003
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Ingår i: Physical Review Letters. - 1079-7114. ; 91:23
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Tidskriftsartikel (refereegranskat)abstract
- The decay-out process of the yrast superdeformed band in Cu-59 has been investigated. The firm determination of spin, parity, excitation energy, and configuration of the states involved in this process constitutes a unique situation for a detailed understanding of the decay-out mechanism. A theoretical model is introduced that includes a residual interaction and tunneling matrix element between bands, calculated in the configuration-dependent cranked Nilsson-Strutinsky model. This interaction causes the decay to occur via a small number of observed doorway states.
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| 2. |
- Andreoiu, Corina, et al.
(författare)
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Evolution of Shapes in 59Cu
- 2002
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 14:3, s. 317-348
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Tidskriftsartikel (refereegranskat)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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| 3. |
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| 4. |
- Chiara, CJ, et al.
(författare)
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Transition Quadrupole Moments in the Superdeformed Band of 40Ca
- 2003
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 67:4
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Tidskriftsartikel (refereegranskat)abstract
- The transition quadrupole moments Q(t) for the superdeformed band in Ca-40 have been determined through thin-target Doppler-shift attenuation analyses. A best-fit value of Q(t)=1.30+/-0.05 e b is obtained when a single value is assumed for the entire band. Fitting separate quadrupole moments for in-band transitions decaying from the high-spin states and the presumably admixed low-spin states results in Q(t)(high)= 1.81(-0.26)(+0.41) e b and Q(t)(low)=1.18(-0.05)(+0.06) e b, respectively. Q(t) values extracted for individual transitions in a Doppler-broadened line-shape analysis also indicate smaller Q(t) values at lower spins. These results are consistent with the interpretation of this band as an eight-particle-eight-hole superdeformed band with a significant admixture of less-collective configurations at low spins.
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| 5. |
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| 6. |
- du Rietz, Rickard, et al.
(författare)
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Investigation of High-spin States in 53Fe
- 2005
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 72:1
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Tidskriftsartikel (refereegranskat)abstract
- The fusion-evaporation reactions Si-28(S-32,1 alpha 2p1n)Fe-53 at 125 MeV and Mg-24(S-32,2p1n)Fe-53 at a 95-MeV beam energy were used to investigate excited states in Fe-53. The combination of the Gammasphere Ge detector array and ancillary devices led to the construction of an extensive level scheme comprising some 90 transitions connecting 40 states. The lifetime of the yrast 25/2(-) state and upper limits for the lifetimes of a number of additional states were determined using the Cologne plunger device coupled to the GASP gamma-ray spectrometer. The experimental results are compared to large-scale shell-model calculations using different sets of two-body matrix elements. In particular, predictions on electromagnetic decay properties such as lifetimes, branching ratios, and mixing ratios are studied in detail.
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| 7. |
- Ekman, Jörgen, et al.
(författare)
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Core Excited States in the A=51 Mirror Nuclei
- 2004
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 70:5
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Tidskriftsartikel (refereegranskat)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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| 8. |
- Ekman, Jörgen, et al.
(författare)
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Evidence for a 1g9/2 Rotational Band in 51Mn
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 66:5, s. 513011-513015
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Tidskriftsartikel (refereegranskat)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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| 9. |
- Ekman, Jörgen, et al.
(författare)
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Gamma-ray Spectroscopy of Core-excited States in 51Mn
- 2004
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 70:1
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Tidskriftsartikel (refereegranskat)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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| 10. |
- Evans, AO, et al.
(författare)
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Magnetic properties of smooth terminating dipole bands in Te-110,Te-112
- 2006
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 636:1, s. 25-30
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Tidskriftsartikel (refereegranskat)abstract
- Three strongly coupled sequences have been established in Te-110,Te-112 up to high spins. They are interpreted in terms of deformed structures built on proton 1-particle-1-hole excitations that reach termination at I similar to 40h. This is the first observation of smooth terminating dipole structures in this mass region. Lifetime measurements have allowed the extraction of experimental B(M 1; 1 -> I - 1) and B(E2; I -> I - 2) reduced transition rates for one of the dipole bands in Te-110. The results support the deformed interpretation. (c) 2006 Elsevier B.V. All rights reserved.
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| 11. |
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| 12. |
- Ideguchi, E, et al.
(författare)
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Superdeformation in the doubly magic nucleus Ca-40(20)20
- 2001
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Ingår i: PHYSICAL REVIEW LETTERS. - : AMERICAN PHYSICAL SOC, COLLEGE PK. - 0031-9007. ; 87:222501, s. 2501-
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Tidskriftsartikel (refereegranskat)abstract
- A rotational band with seven gamma -ray transitions between states with spin 2 (h) over bar and 16 (h) over bar has been observed in the doubly magic, self-conjugate nucleus Ca-40(20)20. The measured transition quadrupole moment of 1.80(-0.29)(+0.39)eb in
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| 13. |
- JIN, HQ, et al.
(författare)
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IDENTIFICATION AND QUADRUPOLE-MOMENT MEASUREMENT OF A SUPERDEFORMED BAND IN ZR-84
- 1995
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 75:8, s. 1471-1474
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Zr-84 were studied using the early implementation phase of the Gammasphere array and the ''Microball'' charged-particle detector system. A cascade of nine gamma rays with a dynamic moment of inertia which is characteristic of superdeformed rotational bands in the A = 80 region has been identified and assigned to Zr-84. The measured transition quadrupole moment of the band corresponds to a prolate quadrupole deformation of beta(2) = 0.53 and confirms the superdeformed nature of this band. This is the first direct experimental confirmation of the existence of the predicted superdeformed shell gap at N similar or equal to 44 particle number.
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| 14. |
- Johansson, Emma, et al.
(författare)
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Gamma-ray Spectroscopy of the Doubly Magic Nucleus 56Ni
- 2006
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 27:2, s. 157-165
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Tidskriftsartikel (refereegranskat)abstract
- The doubly magic N = Z nucleus Ni-56 has been investigated with two fusion-evaporation reactions; Ca-40(Si-28, 3 alpha)Ni-56 at a beam energy of 122MeV and Si-28(S-32, 2p2n)Ni-56 at 130MeV. To detect gamma-rays in coincidence with evaporated particles the Ge-detector array Gammasphere was used in conjunction with the charged-particle detector system, Microball and a 1 pi neutron detector array. Results include a significantly extended level scheme of Ni-56, which is compared to large-scale shell model calculations in the fp shell. The experimental and theoretical results agree to a large extent, with one notable exception; the theoretical model fails to predict the proper sequence of the yrast and yrare 8(+) states.
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| 15. |
- LAFOSSE, DR, et al.
(författare)
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CHARACTERIZATION OF THE FIRST SUPERDEFORMED BAND IN THE A-APPROXIMATE-TO-80 REGION
- 1995
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Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 354:1-2, s. 34-40
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Tidskriftsartikel (refereegranskat)abstract
- The recently discovered superdeformed band in one of the strontium isotopes has been identified as belonging to Sr-83 from a study with the Gammasphere array and the Microball charged-particle detector system. From its decay pattern, a spin of (81 +/- 2)/2 ($) over bar h is deduced for the highest level of this band. Evidence for very fast transition rates and agreement of the characteristics of this band with the theoretical predictions establish the yrast superdeformed nature of this band in Sr-83.
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| 16. |
- LAFOSSE, DR, et al.
(författare)
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EVIDENCE FOR HYPERDEFORMATION IN GD-147
- 1995
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 74:26, s. 5186-5189
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Tidskriftsartikel (refereegranskat)
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| 17. |
- Lipoglavsek, M, et al.
(författare)
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100Sn Core Excitations in 102In
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 65:2
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Tidskriftsartikel (refereegranskat)abstract
- Nuclei in the vicinity of the doubly-magic Sn-100 nucleus have been studied, and an extended level scheme for In-102 has been established. The level structure comprises both the negative parity states involving the nuh(11/2) orbital, and levels due to the breakup of the doubly-magic Sn-100 core. Results of a large-scale shell model calculation, using realistic and empirical effective interactions with Sr-88 as a core, are in very good agreement with the experimental data.
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| 18. |
- Lipoglavsek, M, et al.
(författare)
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Breakup of the Doubly Magic 100Sn Core
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 66:1
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Tidskriftsartikel (refereegranskat)abstract
- Level schemes of Cd-99(48)51 and In-101(49)52 nuclei have been extended to high spin. The breakup of the doubly magic Sn-100 core has been observed. Large-scale shell model calculations based on realistic nucleon-nucleon interactions are in good agreement with the experimental data. These results provide a reliable basis to predict nuclear structure properties in Sn-100 and its neighbors. For example, the size of the N=50 shell gap and the energy of the first excited state in Sn-101 have been deduced.
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| 19. |
- Lipoglavsek, M, et al.
(författare)
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Excited States of the Proton Emitter 105Sb
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 65:5
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in the proton emitter Sb-105 have been investigated for the first time. The nucleus was populated in the reaction Cr-50(Ni-58,1p2n). The GAMMASPHERE Ge-detector array was used together with Microball and the Neutron Shell for selection of the reaction channel. The experimental level scheme agrees well with results of a shell model calculation that uses realistic effective interactions derived from the CD-Bonn nucleon-nucleon interaction and Sn-100 as a closed-shell core.
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| 20. |
- Park, HI, et al.
(författare)
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Rotational structures near 40h in La-123
- 2003
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 68:4
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Tidskriftsartikel (refereegranskat)abstract
- The neutron-deficient nucleus La-123 was studied via the Mo-92(Ca-40,2ap) reaction at a beam energy of 184 MeV. Previously known bands were extended to a much higher spin, and in two cases the structures are now observed near 40 (h) over bar. In addition, three new sequences were identified and linked into previously known bands. The lowest (pi,alpha)=(+,-1/2) structure displays characteristics similar to those of analogous bands in La-127,La-129, which have been proposed as examples of smooth band termination. Cranked Nilsson-Strutinsky calculations were compared with the experimental data in La-123 to determine whether this band is approaching a terminating state as well.
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| 21. |
- Pavan, J, et al.
(författare)
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Lifetime measurements and terminating structures in Nb-87
- 2003
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 67:3: 034316
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Tidskriftsartikel (refereegranskat)abstract
- Two experiments have been performed using the Ni-58(S-32,3p) reaction at 135 MeV with Gammasphere and the Microball to study the high-spin structure of the transitional nucleus Nb-87. The first experiment using a thin target provided a considerable extension and refinement of the level scheme, as well as firm spin assignments from directional correlation of oriented nuclei. Sub-picosecond lifetimes were measured in the second backed-target experiment using the Doppler-shift attenuation method. The lifetimes imply a rather modest average deformation of beta(2)similar to0.1, but with considerable variation from state to state. Strong alternations were observed in the B(M1) strengths of transitions between some pairs of bands. The experimental results were compared with calculations performed within the cranked Nilsson-Strutinsky approach. The calculations generally reproduce the irregularities in the structure of the yrast lines and plunging transition quadrupole moments Q(t) within the bands explaining them as reflections of configuration changes and an approach of band termination, respectively.
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| 22. |
- Rudolph, Dirk, et al.
(författare)
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58Ni: An Unpaired Band Crossing at New Heights of Angular Momentum for Rotating Nuclei
- 2006
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Ingår i: Physical Review Letters. - 1079-7114. ; 96:9
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in Ni-58 have been investigated by means of the fusion-evaporation reaction Si-28(S-32,2p)Ni-58 at 130 MeV beam energy. Discrete-energy levels are observed in Ni-58 at record-breaking 42 MeV excitation energy and angular momenta in excess of 30h. The states form regular rotational bands with unprecedented high rotational frequencies. A comparison with configuration dependent cranked Nilsson-Strutinsky calculations reveals an exceptional two-band crossing scenario, the interaction strength of which is strongly shape dependent.
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| 23. |
- Rudolph, Dirk, et al.
(författare)
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High-resolution In-beam Particle Spectroscopy - New Results on Prompt Proton Emission from 58Cu
- 2002
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 14:2, s. 137-146
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Tidskriftsartikel (refereegranskat)abstract
- Prompt proton decay lines in Cu-58 have been studied by means of high-resolution in-beam particle-gamma coincidence spectroscopy using the GAMMASPHERE Ge-detector array in conjunction with a dedicated set of ancillary detectors including four DeltaE-E silicon-strip telescopes. High-spin states in Cu-58 have been populated via the heavy-ion fusion-evaporation reaction Si-28(Ar-36, 1alpha1p1n) at 148 MeV beam energy. The full-width at half maximum for the proton peak could be reduced significantly compared to earlier experiments. The results indicate that only one prompt proton decay branch exists in the decay-out of the well-deformed band of Cu-58.
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| 24. |
- Rudolph, Dirk, et al.
(författare)
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Prompt Proton Decay Scheme of 59Cu
- 2002
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Ingår i: Physical Review Letters. - 1079-7114. ; 89:2
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Tidskriftsartikel (refereegranskat)abstract
- Five prompt proton decay lines have been identified between deformed states in Cu-59 and three spherical states in Ni-58 by means of high-resolution in-beam particle-gammagamma coincidence spectroscopy. The GAMMASPHERE array coupled to dedicated ancillary detectors including four DeltaE-E silicon strip detectors was used to study high-spin states in Cu-59. The multiple discrete proton lines are found to probe the wave functions of states in the decay-out regime of well- and superdeformed states.
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| 25. |
- Rudolph, Dirk, et al.
(författare)
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Spherical and Deformed High-spin states in 38Ar
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 65:3
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in Ar-38 have been investigated by means of the heavy-ion fusion-evaporation reaction Si-28 +O-16. The level scheme reveals a subtle interplay between spherical, deformed, and superdeformed shapes. Large-scale shell-model calculations in the sd-fp space are invoked to study the microscopic aspects of deformation and shape changes.
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| 26. |
- Skulski, W, et al.
(författare)
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Origin of slow, heavy residues observed in dissipative Au-197+Kr-86 collisions at E/A=35MeV
- 1996
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Ingår i: PHYSICAL REVIEW C-NUCLEAR PHYSICS. - : AMER INST PHYSICS. - 0556-2813. ; 53:6, s. R2594-R2597
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Tidskriftsartikel (refereegranskat)abstract
- An exclusive measurement of slow, massive residues from the Au-197 + Kr-86 reaction at E/A = 35 MeV has been performed in coincidence with projectile-like fragments, neutrons, as well as light- and intermediate-mass charged products. The highly efficient
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| 27. |
- Yu, CH, et al.
(författare)
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Rotational Bands with Terminating Properties in 59Ni
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 65:6
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Tidskriftsartikel (refereegranskat)abstract
- Highly-deformed rotational bands were established in Ni-59 using the Ca-40(Si-29,2p2alpha)Ni-59 reaction. Lifetime measurements indicate that transition quadrupole moments of two of these bands decrease as they smoothly approach their maximum-spin states. The configurations of these bands as well as their band-terminating features are discussed based on configuration-dependent cranked Nilsson-Strutinsky calculations. These calculations indicate that, unlike similar bands observed previously in the region, the two bands in Ni-59 maintain significant collectivity at their I=I-max states.
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