1. |
- Andreoiu, Corina, et al.
(author)
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Yrast Superdeformed Band in 59Cu
- 2000
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 62:5, s. 513011-513015
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Journal article (peer-reviewed)abstract
- High-spin states in 59Cu were populated using the fusion-evaporation reactions 28Si+40Ca at a beam energy of 125 MeV and 36Ar+28Si at a beam energy of 143 MeV. The Gammasphere array in conjunction with ancillary detector systems allowed for the identification of a superdeformed rotational band in 59Cu, which was firmly linked to low-spin yrast states. Using directional correlations of oriented states, a spin-parity assignment of Iπ = 25/2+ to the band head was possible. The average quadrupole moment of the band is measured to be Qt = (2.24±0.40) e b. The characteristics of the band are compared to neighboring nuclei and predictions of different mean-field theories.
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2. |
- Algora, A., et al.
(author)
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Pronounced Shape Change Induced by Quasiparticle Alignment
- 2000
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In: Physical Review C (Nuclear Physics). - 0556-2813 .- 1089-490X. ; 61:3
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Journal article (peer-reviewed)abstract
- Mean lifetimes of high-spin states of Kr-74 have been determined using the Doppler-shift attenuation method. The high-spin states were studied using the Ca-40(Ca-40, alpha 2p) reaction at a beam energy of 160 MeV with the GASP gamma-ray spectrometer. The ground-state band and negative parity side band show the presence of three different configurations in terms of transitional quadrupole deformations. A dramatic shape change was found along the ground-state band after the S-band crossing. The deduced quadrupole deformation changes are well reproduced by cranked Woods-Saxon Strutinsky calculations.
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3. |
- Lagergren, K, et al.
(author)
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Coexistence of superdeformed shapes in Er-154
- 2001
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In: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 8702:2
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Journal article (peer-reviewed)abstract
- A new superdeformed rotational band has been observed in Er-154 using the Euroball Ge detector array. The new band and the one previously observed can be understood as based on coexisting superdeformed structures at prolate and triaxial shapes, respectively. The observation resolves long-standing difficulties in the theoretical interpretation of superdeformed states in Er-154.
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4. |
- 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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5. |
- 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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6. |
- 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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7. |
- Gladnishki, KA, et al.
(author)
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Angular Momentum Population in the Projectile Fragmentation of 238U at 750 MeV/nucleon
- 2004
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 69:2
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Journal article (peer-reviewed)abstract
- A systematic study of the population probabilities of nanosecond and microsecond isomers produced following the projectile fragmentation of U-238 at 750 MeV/nucleon has been undertaken at the SIS/FRS facility at GSI. Approximately 15 isomeric states in neutron-deficient nuclei around A similar to 190 were identified and the corresponding. isomeric ratios determined. The results are compared with a model based on the statistical abrasion-ablation description of relativistic fragmentation and simple assumptions concerning gamma cascades in the final nucleus (sharp cutoff). This model represents an upper limit for the population of isomeric states in relativistic projectile fragmentation. When the decay properties of the states above the isomer are taken into account, as opposed to the sharp cutoff approximation, a good agreement between the experimental and calculated angular momentum population is obtained.
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8. |
- Gladnishki, KA, et al.
(author)
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Isomer spectroscopy in the neutron-deficient lead region following projectile fragmentation
- 2003
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In: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254. ; 34:4, s. 2395-2398
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Journal article (peer-reviewed)abstract
- Projectile fragmentation of a 750 MeV/nucleon U-238 beam was used to populate neutron-deficient nuclei around A similar to190. Isomeric states in Hg, Tl, Pb, Bi, and Po isotopes were identified and their lifetimes determined, with the ultimate aim of measuring their isomeric ratios to provide information on the spin population in such reactions.
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9. |
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10. |
- Weiszflog, M., et al.
(author)
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High-spin spectroscopy of Ga-63(31)32 and Ga-65(31)34
- 2001
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In: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 11:1, s. 25-38
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Journal article (peer-reviewed)abstract
- High-spin states in the nuclei Ga-63 and Ga-65 were studied following the reaction S-32 + Ca-40 at a reaction energy of 125 MeV and using the GASP gamma -ray spectrometer in combination with the ISIS charged-particle detector system. In addition to low-lying negative-parity states with single-particle character, rotational-like cascades built on the 9/2(+) and 19/2(-) states have been observed in both nuclei. Sidebands with negative parity in Ga-63 and positive parity in Ga-65 could be established. The experimental results are compared with Total Routhian Surface calculations which describe the nuclei as moderately deformed (beta (2) approximate to 0.25) and gamma soft at low rotational frequencies. The highest experimentally observed positive-parity state in Ga-65 (41/2(+)) is in good agreement with the calculated crossing of the collective band with a non-collective one terminating at this spin.
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11. |
- Ashrafi, S., et al.
(author)
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Monte-Carlo simulation of the charged particle detector used in the NORDBALL gamma-ray spectrometer
- 2001
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In: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 458:3, s. 690-697
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Journal article (peer-reviewed)abstract
- The NORDBALL silicon detector array for detecting light charged particles emitted in fusion evaporation reactions was simulated with the Monte-Carlo method. The data from the reaction of 261 MeV Ni-58 ions with Cr-50 nuclei in a 4.8 mg/cm(2) thick target was used to adjust the simulation parameters. Relative population of residual nuclei in the reaction was determined, by comparing the intensities of gamma -rays.
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12. |
- Ekman, Jörgen, et al.
(author)
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Unusual Isospin-Breaking and Isospin-mixing Effects in the A=35 Mirror Nuclei
- 2004
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In: Physical Review Letters. - 1079-7114. ; 92:13
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Journal article (peer-reviewed)abstract
- Excited states have been studied in Ar-35 following the O-16(Mg-24,1alpha1n)Ar-35 fusion-evaporation reaction at 60 MeV using the Ge-detector array GASP. A comparison with the mirror nucleus Cl-35 shows two remarkable features: (i) A surprisingly large energy difference for the 13/2(-) states, in which the hitherto overlooked electromagnetic spin-orbit term is shown to play a major role, and (ii) a very different decay pattern for the 7/2(-) states, which provides direct evidence of isospin mixing.
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13. |
- Fahlander, Claes, et al.
(author)
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Evolution and Destruction of Shapes in 59Cu
- 2002
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In: Challenges of Nuclear Structure. Proceedings of the 7th International Spring Seminar on Nuclear Physics. - 9810247257 ; , s. 393-400
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Conference paper (peer-reviewed)abstract
- An extensive high-spin level scheme has been established in 59Cu using a heavy-ion fusion evaporation reaction and the GAMMASPHERE multidetector array in conjunction with MICROBALL. Next to the spherical states at low excitation energy a large number of regular sequences of high-energy γ-ray transitions have been observed, which form rotational bands with various degree of deformation. For the yrast superdeformed band about 90% of the intensity of the discrete γ decay-out, distributed over about 30 decay paths, is known, which allows for a detailed study of this decay-out process. Two of the deformed bands were found to decay by prompt proton emission into two different spherical states of 58Ni, in direct competition with the γ decay-out process
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14. |
- Fahlander, Claes, et al.
(author)
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Excited States in 103Sn: Neutron Single-particle Energies with Respect to 100Sn
- 2001
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In: Physical Review C (Nuclear Physics). - 0556-2813 .- 1089-490X. ; 63:2
-
Journal article (peer-reviewed)abstract
- Gamma-ray lines from Sn-103 have been identified for the first time using EUROBALL and ancillary detectors. The level scheme of Sn-103 has been established by means of particle-gated gamma gamma coincidences. The energy spacing between the g(7/2) and d(5/2) neutron single-particle orbitals is determined from the excited states in Sn-103.
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15. |
- Lipoglavsek, M, et al.
(author)
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100Sn Core Excitations in 102In
- 2002
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 65:2
-
Journal article (peer-reviewed)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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16. |
- Lipoglavsek, M, et al.
(author)
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Breakup of the Doubly Magic 100Sn Core
- 2002
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 66:1
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Journal article (peer-reviewed)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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17. |
- Lipoglavsek, M, et al.
(author)
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Excited States of the Proton Emitter 105Sb
- 2002
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 65:5
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Journal article (peer-reviewed)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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18. |
- Palacz, M., et al.
(author)
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Investigations of Neutron Deficient Nuclei Close to 100Sn with EUROBALL
- 2001
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In: Acta Physica Polonica. Series B: Elementary Particle Physics, Nuclear Physics, Statistical Physics, Theory of Relativity, Field Theory. - 0587-4254 .- 1509-5770. ; 32, s. 999-1003
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Journal article (peer-reviewed)abstract
- Excited states of nuclei in the vicinity of Sn-100 have been studied using: the EUROBALL detector array. Gamma-ray lines from Sn-103 have been identified for the first time, and a level scheme of low-lying excited states of Sn-103 has been established. New constraints on energies of single particle orbitals with respect to the Sn-100 core are obtained.
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19. |
- Rudolph, Dirk, et al.
(author)
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Gamma-decay Lifetime Measurements in the Second Minimum of 58Cu
- 2001
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In: Physical Review C (Nuclear Physics). - 0556-2813. ; 63:2
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Journal article (peer-reviewed)abstract
- The individual lifetimes of three low-lying states in the proton-decaying well-deformed rotational band in the second minimum of the N = Z nucleus Cu-58 were determined. Doppler-shift attenuated gamma -ray lineshapes were analyzed following the fusion-evaporation reaction C-40,(Mg-24,1 alpha 1p1n)Cu-58 and using the EUROBALL gamma -ray spectrometer coupled to ancillary detector systems. The deduced transitional quadrupole moments confirm the predicted increase of deformation towards the bottom of the band. The gamma decay-out strength hints towards a nonstatistical pattern.
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20. |
- Rudolph, Dirk, et al.
(author)
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The Lifetime of the Proton-decaying 8915 keV State in 58Cu
- 2001
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In: Nuclear Physics, Section A. - 0375-9474. ; 694, s. 132-146
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Journal article (peer-reviewed)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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21. |
- Sohler, D, et al.
(author)
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Neutron Excitations Across the N=50 Shell Gap in 102In
- 2002
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In: Nuclear Physics, Section A. - : Elsevier. - 0375-9474 .- 1873-1554. ; 708:3-4, s. 181-189
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Journal article (peer-reviewed)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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22. |
- Weiszflog, M., et al.
(author)
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High-spin Spectroscopy of 63Ga and 65Ga
- 2001
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In: European Physical Journal A. Hadrons and Nuclei. - 1434-6001. ; 11, s. 25-38
-
Journal article (peer-reviewed)abstract
- High-spin states in the nuclei Ga-63 and Ga-65 were studied following the reaction S-32 + Ca-40 at a reaction energy of 125 MeV and using the GASP gamma -ray spectrometer in combination with the ISIS charged-particle detector system. In addition to low-lying negative-parity states with single-particle character, rotational-like cascades built on the 9/2(+) and 19/2(-) states have been observed in both nuclei. Sidebands with negative parity in Ga-63 and positive parity in Ga-65 could be established. The experimental results are compared with Total Routhian Surface calculations which describe the nuclei as moderately deformed (beta (2) approximate to 0.25) and gamma soft at low rotational frequencies. The highest experimentally observed positive-parity state in Ga-65 (41/2(+)) is in good agreement with the calculated crossing of the collective band with a non-collective one terminating at this spin.
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