1. |
- Ertoprak, Aysegul, et al.
(författare)
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Evidence for octupole collectivity in 172Pt
- 2020
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Ingår i: European Physical Journal A. - : Springer. - 1434-6001 .- 1434-601X. ; 56:2
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Tidskriftsartikel (refereegranskat)abstract
- Excited states in the extremely neutron-deficient nucleus 172Pt were populated via 96Ru(78Kr,2p) and 92Mo(83Kr,3n) reactions. The level scheme has been extended up to an excitation energy of ~ 5 MeV and tentative spin-parity assignments up to Iπ = 18+. Linear polarization and angular distribution measurements were used to determine the electromagnetic E1 character of the dipole transitions connecting the positive-parity ground-state band with an excited side-band, firmly establishing it as a negative-parity band. The lowest member of this negative-parity structure was firmly assigned spin-parity 3-. In addition, we observed an E3 transition from this 3- state to the ground state, providing direct evidence for octupole collectivity in 172Pt. Large-scale shell model (LSSM) and total Routhian surface (TRS) calculations have been performed, supporting the interpretation of the 3- state as a collective octupole-vibrational state.
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2. |
- Hadinia, Baharak, et al.
(författare)
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Identification of gamma rays from Au-172 and alpha decays of Au-172, Ir-168, and Re-164
- 2009
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 80:6, s. 064310-
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Tidskriftsartikel (refereegranskat)abstract
- The very neutron deficient odd-odd nucleus Au-172 was studied in reactions of 342 and 348 MeV Kr-78 beams with an isotopically enriched Ru-96 target. The alpha decays previously reported for Au-172 were confirmed and the decay chain extended down to Tm-152 through the discovery of a new alpha-decaying state in Re-164 [E-alpha=5623(10) keV; t(1/2)=864(-110)(+150) ms; b(alpha)=3(1)%]. Fine structure in these alpha decays of Au-172 and Ir-168 were identified. A new alpha-decaying state was also observed and assigned as the ground state in Au-172 [E-alpha=6762(10) keV; t(1/2)=22(-5)(+6) ms]. This decay chain was also correlated down to Tm-152 through previously reported alpha decays. Prompt gamma rays from excited states in Au-172 have been identified using the recoil-decay tagging technique. The partial level scheme constructed for Au-172 indicates that it has an irregular structure. Possible configurations of the alpha-decaying states in Au-172 are discussed in terms of the systematics of nuclei in this region and total Routhian surface calculations.
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3. |
- Juutinen, S, et al.
(författare)
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Coexistence of collective and quasiparticle structures in Sn-106 and Sn-108
- 1997
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Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 617:1, s. 74-90
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Tidskriftsartikel (refereegranskat)abstract
- New levels in the neutron deficient nuclei Sn-106 and Sn-108 have been investigated by using the NORDBALL detector array combined with charged particle and neutron detectors. The excited structures are discussed in terms of collectivity and the shell model. The excitations are interpreted to be based on d5/2, g7/2 and h(11/2) both for protons and neutrons and g(9/2) for protons. The systematical behaviour of the specific states in the Sn isotopes is studied in the mass range of A = 106-118.
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4. |
- Juutinen, S, et al.
(författare)
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Coexistence of collective and quasiparticle structures in Sn-106 and Sn-108
- 1997
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Ingår i: NUCLEAR PHYSICS A. - : ELSEVIER SCIENCE BV. - 0375-9474. ; 617:1, s. 74-90
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- New levels in the neutron deficient nuclei Sn-106 and Sn-108 have been investigated by using the NORDBALL detector array combined with charged particle and neutron detectors. The excited structures are discussed in terms of collectivity and the shell mode
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5. |
- Kownacki, J, et al.
(författare)
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High-spin studies of the neutron deficient nuclei In-103, In-105, In-107, and In-109
- 1997
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Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 627:2, s. 239-258
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states of the isotopes 103,105,107,109In have been investigated using in-beam γ-ray spectroscopic methods. Results from three different experiments are presented. Targets of 54Fe, 50Cr, and 92Mo were bombarded by a 270 and 261 MeV 58Ni beam and by a 95 MeV 19F beam, respectively. Reaction channel separation was achieved with a charged-particle detector array and in the first two experiments also with a 1π neutron detector system. As a result of these experiments the level schemes of 103,105,107,109In were significantly extended. Excited states of these odd-A indium isotopes are discussed within the framework of the nuclear shell model and the hole-core coupling scheme. The systematics of excited states of light odd-A indium isotopes is also discussed.
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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. |
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8. |
- Chiara, C. J., et al.
(författare)
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Probing sd-fp Cross-shell Interactions via Terminating Configurations in 42Sc,43Sc
- 2007
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 75:5
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Tidskriftsartikel (refereegranskat)abstract
- An experimental study of the lower fp-shell nuclei Sc-42,Sc-43 was performed via alpha pn and alpha p evaporation, respectively, from Ne-20 + Si-28 and Mg-24 + Mg-24 fusion-evaporation reactions. The experiments were conducted with the Gammasphere and Microball detector arrays. The level schemes of both nuclei have been extended considerably. Terminating states associated with the f(7/2)(n) and d(3/2)(-1)f(7/2)(n+1) configurations were identified in each nuclide and incorporated into detailed comparisons with neighboring nuclei and with shell model calculations. The energy differences between the terminating states provide a test of the sd-fp cross-shell interactions in these calculations.
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9. |
- DOMBRADI, Z, et al.
(författare)
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HIGH-SPIN SPECTROSCOPY OF TE-109
- 1995
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 51:5, s. 2394-2399
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Tidskriftsartikel (refereegranskat)
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10. |
- DOMBRADI, Z, et al.
(författare)
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IDENTIFICATION AND SPECTROSCOPY OF THE TE-108 NUCLEUS
- 1994
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Ingår i: Zeitschrift für Physik A Hadrons and Nuclei. - 0939-7922 .- 1431-5831. ; 350:1, s. 3-4
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Tidskriftsartikel (refereegranskat)abstract
- Excited states of Te-108 were populated in the Fe-54 + Ni-58 (270 MeV) reaction using the NORDBALL detector array equipped with charged-particle and neutron detector systems for reaction channel separation. Gamma rays belonging to the neutron deficient nucleus Te-108 were identified for the first time. On the basis of gammagamma-coincidence and angular correlation relations a level scheme was constructed with tentative spin and parity assignments. The structure of the nucleus is discussed in the framework of systematics of heavier Te nuclei.
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11. |
- Ertoprak, Aysegul, et al.
(författare)
-
Lifetime measurements of core-excited states in semi-magic 95Rh
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Lifetimes of negative-parity states have been determined in the semi-magic (N=50) nucleus 95Rh. The fusion-evaporation reaction 58Ni(40Ca, 3p) was used to populate high-spin states in 95Rh at the Grand Accelerateur National d'Ions Lourds (GANIL) accelerator facility. The results were obtained using the Doppler Shift Attenuation Method (DSAM) based on the Doppler broadened line shapes produced during the slowing down process of the residual nuclei in a thick 6~ mg/cm2 metallic target. B(M1) and B(E2) reduced transition strengths are compared with predictions from large-scale shell-model calculations.
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12. |
- Ertoprak, Aysegul, et al.
(författare)
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LIFETIME MEASUREMENTS WITH THE DOPPLER SHIFT ATTENUATION METHOD USING A THICK HOMOGENEOUS PRODUCTION TARGET - VERIFICATION OF THE METHOD
- 2017
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Ingår i: Acta Physica Polonica B. - : Jagiellonian University Press. - 0587-4254 .- 1509-5770. ; 48:3, s. 325-329
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Tidskriftsartikel (refereegranskat)abstract
- Doppler Shift Attenuation Method (DSAM) analysis of excited-state lifetimes normally employs thin production targets mounted on a thick stopper foil ("backing") serving to slow down and stop the recoiling nuclei of interest in a well-defined manner. Use of a thick, homogeneous production target leads to a more complex analysis as it results in a substantial decrease in the energy of the incident projectile which traverses the target with an associated change in the production cross section of the residues as a function of penetration depth. Here, a DSAM lifetime analysis using a thick homogeneous target has been verified using the Doppler broadened lineshapes of gamma rays following the decay of highly excited states in the semi-magic (N = 50) nucleus Ru-94. Lifetimes of excited states in the Ru-94 nucleus have been obtained using a modified version of the LINESHAPE package from the Doppler broadened lineshapes resulting from the emission of the gamma rays, while the residual nuclei were slowing down in the thick (6 mg/cm(2)) metallic Ni-58 target. The results have been validated by comparison with a previous measurement using a different (RDDS) technique.
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13. |
- Ertoprak, A., et al.
(författare)
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Lifetimes of core-excited states in semi-magic Rh-95
- 2020
-
Ingår i: European Physical Journal A. - : SPRINGER. - 1434-6001 .- 1434-601X. ; 56:11
-
Tidskriftsartikel (refereegranskat)abstract
- Lifetimes of negative-parity states have been determined in the neutron deficient semi-magic (N = 50) nucleus Rh-95. The fusion-evaporation reaction Ni-58(Ca-40, 3p) was used to populate high-spin states in Rh-95 at the Grand Accelerateur National d'Ions Lourds (GANIL) accelerator facility. The results were obtained using the Doppler Shift Attenuation Method (DSAM) based on the Doppler broadened line shapes produced during the slowing down process of the residual nuclei in a thick 6 mg/cm(2) metallic target. B(M1) and B(E2) reduced transition strengths are compared with predictions from large-scale shell-model calculations. state-of-the-art theory. Remarkably, the structural features up to moderate angular momentum of nuclei immediately below the N = Z = 50 shell closures can be described with high accuracy in a very simple way by shell-model calculations including only the g(9/2) and p(1/2) subshells. Of special interest is the neutron-proton pair coupling scheme which is expected to appear in the heaviest N=Z nuclei [1,2] and the seniority structure of the N = 50 isotones [3-7]. However, multiple core-excited states have been observed in the semi-magic nuclei of the Sn-100 region [8-10]. The theoretical study of those states is a challenging task, which requires a significantly larger model space for their interpretation. Transition probabilities between nuclear states provide important constraints for theoretical modelling of the structure of the nuclei of interest. Our previous lifetime study of the semimagic (N = 50) nucleus Ru-94 [ 11,12] provided information on the electromagnetic decay properties of neutron-core excited states. We now address lifetime measurements in its closest, more neutron deficient, isotone Rh-95 using the same DSAM technique. The experimental results have been interpreted within the framework of large-scale shell-model (LSSM) calculations.
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14. |
- Ertoprak, Aysegul, 1987-, et al.
(författare)
-
M1 and E2 transition rates from core-excited states in semi-magic 94Ru
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Lifetimes of high-spin states have been measured in the semi-magic (N=50) nucleus 94Ru. Excited states in 94Ru were populated in the 58Ni(40Ca, 4p)94Ru∗ fusion-evaporation reaction at the Grand Accelerateur National d’Ions Lourds (GANIL) accelerator complex. DSAM lifetime analysis was performed on the Doppler broadened line shapes in energy spectra obtained from γ-rays emitted while the residual nuclei were slowing down in a thick 6 mg/cm2 metallic 58Ni target. In total eight excited-state lifetimes in the angular momentum range I = (13 − 20)ħ have been measured, five of which were determined for the first time. The deduced corresponding B(M1) and B(E2)reduced transition strengths are discussed within the framework of large-scale shell model calculations to study the contribution of different particle-hole configurations, in particular for analyzing contributions from core-excited configurations.
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15. |
- Ertoprak, Aysegul, et al.
(författare)
-
M1 and E2 transition rates from core-excited states in semi-magic Ru-94
- 2018
-
Ingår i: European Physical Journal A. - : Springer. - 1434-6001 .- 1434-601X. ; 54:9
-
Tidskriftsartikel (refereegranskat)abstract
- Lifetimes of high-spin states have been measured in the semi-magic (N = 50) nucleus Ru-94. Excited states in Ru-94 were populated in the Ni-58(Ca-40, 4p)Ru-94* fusion-evaporation reaction at the Grand Accelerateur National d'Ions Lourds (GANIL) accelerator complex. DSAM lifetime analysis was performed on the Doppler broadened line shapes in energy spectra obtained from gamma-rays emitted while the residual nuclei were slowing down in a thick 6 mg/cm(2) metallic Ni-58 target. In total eight excited-state lifetimes in the angular momentum range I = (13-20)h have been measured, five of which were determined for the first time. The corresponding B(M1) and B(E2) reduced transition strengths are discussed within the framework of large-scale shell model calculations to study the contribution of different particle-hole configurations, in particular for analyzing contributions from core-excited configurations.
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16. |
- 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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17. |
- Ghazi Moradi, Farnaz, 1976-, et al.
(författare)
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Character of particle-hole excitations in Ru-94 deduced from gamma-ray angular correlation and linear polarization measurements
- 2014
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 89:1, s. 014301-
-
Tidskriftsartikel (refereegranskat)abstract
- Linear polarization and angular correlations of gamma-rays depopulating excited states in the neutron-deficient nucleus Ru-94(44)50 have been measured, enabling firm spin-parity assignments for several excited states in this nucleus. The deduced multipolarities of strong transitions in the yrast structure were found to be mostly of stretched M1, E1, and E2 types and, in most cases, in agreement with previous tentative assignments. The deduced multipolarity of the 1869 keV and the connecting 257 and 1641 keV transitions indicates that the state at 6358 keV excitation energy has spin parity 12(1)(-) rather than 12(3)(+) as proposed in previous works. The presence of a 12(1)(-) state is interpreted within the framework of large-scale shell-model calculations as a pure proton-hole state dominated by the pi(p(1/2)(-1)circle times g(9/2)(-5)) and pi(p(3/2)(-1) g(9/2)(-5)) configurations. A new positive-parity state is observed at 6103 keV and is tentatively assigned as 12(2)(+). The 14(1)(-) state proposed earlier is reassigned as 13(4)(-) and is interpreted as being dominated by neutron particle-hole core excitations. The strengths of several E1 transitions have been measured and are found to provide a signature of core-excited configurations.
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18. |
- Ghazi Moradi, Farnaz, et al.
(författare)
-
Spectroscopy of the neutron-deficient N=50 nucleus Rh-95
- 2014
-
Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 89:4, s. 044310-
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Tidskriftsartikel (refereegranskat)abstract
- The neutron-deficient semimagic (neutron number N = 50) Rh-95 nucleus has been produced at high spins using the projectile-target system Ca-40 + Ni-58 at 125 MeV beam energy. The gamma-decays of levels populated by the 3p fusion evaporation reaction channel were studied using gamma-gamma coincidences, and 20 new gamma-ray transitions involving 15 new positive-and negative-parity states were observed. Spin and parity for many of the excited states were firmly deduced for the first time using the combined directional angular correlation and direction-polarization techniques. The observed structures are discussed within the framework of large-scale shell model calculations. E1 transition strengths were deduced and used together with the results of the shell model calculations to study the contribution of different particle-hole configurations, in particular for analyzing contributions from core-excited configurations.
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19. |
- Hadinia, Baharak, et al.
(författare)
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First identification of gamma-rays in Te-106 using recoil decay tagging technique
- 2006
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Ingår i: Frontiers in Nuclear Structure Astrophysics, and Reactions: FINUSTAR. - MELVILLE, NY : AMER INST PHYSICS. - 0735403236 - 9780735403239 ; , s. 457-459
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Konferensbidrag (refereegranskat)abstract
- Gamma-ray transitions from excited states in Te-106 have been identified using the recoil decay tagging technique. The experiment which was the reaction Fe-54(Fe-54,2n)Te-106* was performed at the JYFL accelerator facility at the University of Jyvaskyla, Finland. The production cross section was estimated at 25 nb, a new limit for in-beam gamma-ray spectroscopy. A tentative level structure for the ground state band of Te-106 is proposed.
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20. |
- Ideguchi, E., et al.
(författare)
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High-spin intruder band in In-107
- 2010
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 81:3, s. 034303-
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in the neutron-deficient nucleus In-107 were studied via the Ni-58(Cr-52,3p) reaction. In-beam gamma rays were measured using the JUROGAM detector array. A rotational cascade consisting of ten gamma-ray transitions, which decays to the 19/2(+) level at 2.002 MeV, was observed. The band exhibits the features typical for smooth terminating bands that also appear in rotational bands of heavier nuclei in the A similar to 100 region. The results are compared with total Routhian surface and cranked Nilsson-Strutinsky calculations.
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21. |
- JOHNSON, A, et al.
(författare)
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HIGH-SPIN STUDIES NEAR SN-100 WITH NORDBALL - NEW RESULTS ON IN-102, IN-104 AND SB-108
- 1993
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Konferensbidrag (refereegranskat)abstract
- The NORDBALL detector array has been used in a gamma-ray spectroscopic study of neutron deficient nuclei close to 100Sn. A beam of 270 MeV 58Ni ions was used to bombard a target of Fe-54. Reaction channel separation was achieved with a 4pi charged particle Si-ball together with a 1pi neutron detector wall. Altogether 29 final nuclei were identified and excited states were observed for the first time in 8 of them. The weakest identified channel was 100Cd which represented 4.10(-3) % of the observed total yield. Level schemes Of 102In, 104In and 108Sb constructed from gamma-gamma-particle-coincidence and gamma-gamma-angular correlation analyses are presented. The observed structures are discussed in the framework of the nuclear shell-model. In 108Sb also a deformed, strongly coupled, level sequence is observed. This deformed structure is interpreted as built on a pig9/2(-1)xnuh11/2 configuration in agreement with TRS calculations.
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22. |
- KARNY, M, et al.
(författare)
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EXCITED-STATES OF I-111 AND THE OBSERVATION OF A 21-NS ISOMER
- 1994
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Ingår i: Zeitschrift für Physik A Hadrons and Nuclei. - 0939-7922 .- 1431-5831. ; 350:3, s. 179-180
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Tidskriftsartikel (refereegranskat)abstract
- Proton rich nuclei close to Sn-100 have been investigated an-beam using the NORDBALL detector array. A beam of 270 MeV Ni-58 was used to bombard a Fe-54 target. Reaction channel separation was achieved with a 4 pi charged particle multi-detector set-up together with a 1 pi neutron detector wall placed in the forward direction. Gamma-ray transitions belonging do the I-111 nucleus were identified for the first time. A level scheme constructed from gamma-gamma-perticle-coincidence analysis is proposed. The level structure is discussed within the framework of the shell model and the systematics of the heavier odd iodine nuclei.
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23. |
- KLAMRA, W, et al.
(författare)
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HIGH-SPIN BAND STRUCTURES IN CD-104
- 1995
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Ingår i: Zeitschrift für Physik A Hadrons and Nuclei. - 0939-7922 .- 1431-5831. ; 352:2, s. 117-118
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Tidskriftsartikel (refereegranskat)abstract
- High spin states in Cd-104 have been investigated by means of heavy ion induced reactions using the Nordball detector array. The level scheme constructed from yy-coincidences is dominated by three band structures, The positive parity band shows no rotational like energy spacing, It is thus understood mostly in terms of quasiparticle excitations with vd(5/2), Vg(7/2) and pi g(9/2) configurations, The collective properties of the negative parity bands are more pronounced. These bands are most likely due to v(h(11/2),d(5/2)) and v(h(11/2)g(7/2)) structures.
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24. |
- KLAMRA, W, et al.
(författare)
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HIGH-SPIN BAND STRUCTURES IN CD-104
- 1995
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Ingår i: ZEITSCHRIFT FUR PHYSIK A-HADRONS AND NUCLEI. - : SPRINGER VERLAG. - 0939-7922. ; 352:2, s. 117-118
-
Tidskriftsartikel (refereegranskat)abstract
- High spin states in Cd-104 have been investigated by means of heavy ion induced reactions using the Nordball detector array. The level scheme constructed from yy-coincidences is dominated by three band structures, The positive parity band shows no rotatio
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25. |
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26. |
- Lieder, R M, et al.
(författare)
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Gamma-ray tracking arrays
- 2001
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Ingår i: PROGRESS IN PARTICLE AND NUCLEAR PHYSICS, VOL 46. ; , s. 399-407
-
Konferensbidrag (refereegranskat)abstract
- The next generation of 4 pi arrays for high-precision gamma -ray spectroscopy will involve "gamma -ray tracking front-end on digital signal processing techniques, which allows to extract energy, timing and spatial information on the interactions of a gamma -ray in the Ge detector by pulse shape analysis of its signals. Utilizing the information on the positions of the interaction points and the energies released at each point the tracks of the gamma -rays in a Ge shell can be reconstructed in three dimensions.
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27. |
- MAKELA, E, et al.
(författare)
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COEXISTENCE OF COLLECTIVE AND QUASI-PARTICLE STRUCTURES IN SN-106,SN-108 NUCLEI
- 1995
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Ingår i: Physica scripta. T. - : ROYAL SWEDISH ACAD SCIENCES. - 0281-1847. ; T56, s. 280-283
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Tidskriftsartikel (refereegranskat)abstract
- New revels in two neutron deficient nuclei Sn-106.108 have been found by using the Nordball detector array extended with the arrangements of charged particle and neutron detectors. The excited structures are discussed in terms of collectivity and the shell model. The systematical behaviour of the states in Sn isotopes is studied in the mass range of A = 104-118.
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28. |
- Milanović, T., et al.
(författare)
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Lifetime measurements of low-lying states in 73Ga and 70,72,74Zn isotopes
- 2020
-
Ingår i: Acta Physica Polonica B. - 0587-4254. ; 51:3, s. 837-842
-
Tidskriftsartikel (refereegranskat)abstract
- Lifetimes of low-lying states in 73Ga and 70,72,74Zn were measured using the Recoil Distance Doppler Shift (RDDS) method. These nuclei were produced in deep-inelastic reactions in inverse kinematics with a 208Pb beam impinging on a 76Ge target. Prompt γ rays were detected using the AGATA tracking array coupled to the VAMOS++ spectrometer. Lifetime of the 5/2- state in 73Ga, measured for the first time, provides additional evidence for the existence of a 1/2-, 3/2- ground-state doublet. The lifetimes of the 4+ states in 70,72,74Zn were remeasured in an attempt to understand the discrepancies observed between earlier measurements. Our results are in agreement with those of previous plunger experiments.
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29. |
- SEWERYNIAK, D, et al.
(författare)
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IN-BEAM GAMMA-RAY SPECTROSCOPY OF IN-102
- 1993
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Ingår i: Zeitschrift für Physik A Hadrons and Nuclei. - 0939-7922 .- 1431-5831. ; 345:2, s. 243-244
-
Tidskriftsartikel (refereegranskat)abstract
- Neutron deficient nuclei close to 100Sn have been investigated in-beam by gamma-ray spectroscopic methods using the NORDBALL detector array. A beam of 270 MeV Ni-58 was used to bombard a target of Fe-54. Reaction channel separation was achieved with a 4pi charged particle multi-detector set-up together with a 1pi neutron detector wall placed in the forward direction. Excited states of 102In were identified for the first time. The level scheme constructed from gamma-gamma-particle-coincidence and gamma-gamma-angular correlation analysis is presented. The structure of 102In is discussed and compared to neighboring nuclei in the framework of the nuclear shell-model.
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30. |
- SEWERYNIAK, D, et al.
(författare)
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IN-BEAM SPECTROSCOPY AT THE PROTON-DRIP LINE - FIRST OBSERVATION OF EXCITED-STATES IN SB-106 AND SB-107
- 1994
-
Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 321:4, s. 323-328
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Tidskriftsartikel (refereegranskat)abstract
- Neutron deficient nuclei close to Sn-100 have been investigated in-beam using the NORDBALL detector array. A target of Fe-54 was bombarded with a beam of Ni-58 at 270 MeV. Evaporation residues were identified by detecting protons and alpha particles in a 4 pi charged particle multi-detector set-up and neutrons in a 1 pi neutron detector wall in coincidence with gamma rays. Excited states of the proton drip line nucleus Sb-106 and of Sb-107 were identified for the first time. The yrast level schemes constructed from gamma-gamma-particle coincidence and gamma-gamma angular correlation analysis are presented and discussed within the framework of the nuclear shell model.
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31. |
- SEWERYNIAK, D, et al.
(författare)
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IN-BEAM STUDY OF IN-102, IN-104 AND IN-106
- 1995
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Ingår i: Nuclear Physics A. - 0375-9474 .- 1873-1554. ; 589:1, s. 175-200
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Tidskriftsartikel (refereegranskat)abstract
- Proton-rich odd-odd In isotopes have been investigated by in-beam spectroscopic methods using the NORDBALL detector array. A Ni-58 beam with an energy of 270 MeV was used to bombard a Fe-54 target. Separation of different reaction channels was achieved with a 4 pi charged-particle multi-detector set-up together with a 1 pi neutron detector wall placed in the forward direction. Excited states of the In-102 nucleus were identified for the first time as well as a set of negative-parity states in In-104. In In-106 the information about positive- and negative-parity states has been extended. The nuclei are discussed within the framework of the nuclear shell model, the interacting boson-fermion-fermion model and the systematics of the heavier odd-odd indium isotopes.
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32. |
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33. |
- Shimoura, S., et al.
(författare)
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Lifetime of the isomeric O-2(+) state in Be-12
- 2007
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 654:3-4, s. 87-91
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Tidskriftsartikel (refereegranskat)abstract
- Mean lifetime tau of the isomeric O-2(+) state in Be-12 has been determined by measuring decay spectra of delayed y-rays from stopped Be-12 2 nuclei produced by the projectile fragmentation of O-18 at 100 A MeV. A consistent value of tau = 331 +/- 12 ns was obtained from the time spectra of the E2 gamma decay to the 2(1)(+) state and the positron annihilation following the E0 decay to the ground state. Based on the observed branching ratio between the E2 and E0 decays, transition strengths of the two decay modes were deduced to be B(E2; O-2(+) -> 2(1)(+)) = 7.0 +/- 0.6 e(2) fm(4) and 2 1 1 (O-2(+) Sigma(i) e(i) r(i)(2) O-1(+)), = 0.87 +/- 0.03 e fM(2), respectively. (C) 2007 Elsevier B.V. All rights reserved.
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34. |
- Slunga, E., et al.
(författare)
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Scintillation response of BaF2 and YAlO3 : Ce (YAP : Ce) to energetic ions
- 2001
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 469:1, s. 70-76
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Tidskriftsartikel (refereegranskat)abstract
- The scintillation response of BaF2 and YAP: Ce to protons. a particles, O-16 and Si-28 ions in the 5-30 MeV range has been investigated. The ratio between the fast and slow parts of the scintillator signal for BaF2 has been used to separate protons, a particles and heavier ions, and the dependence of this ratio on the particle energy has been studied. The time constants and intensities of the two components of the YAP: Ce signal were measured, as were the time constant and intensity of the weak component of the slow part of the BaF2 signal. Furthermore, the dependence of the light yield on the particle energy has been investigated for both BaF2 and YAP: Ce.
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35. |
- Bäck, Torbjörn, et al.
(författare)
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Lifetime measurement of the first excited 2(+) state in (108)Te
- 2011
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 84:4, s. 041306-
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Tidskriftsartikel (refereegranskat)abstract
- The lifetime of the first excited 2(+) state in the neutron deficient nuclide (108)Te has been measured for the first time, using a combined recoil decay tagging and recoil distance Doppler shift technique. The deduced reduced transition probability is B(E2;0(g.s.)(+) -> 2(+)) = 0.39(-0.04)(+0.05)e(2)b(2). Compared to previous experimental data on neutron deficient tellurium isotopes, the new data point constitutes a large step (six neutrons) toward the N = 50 shell closure. In contrast to what has earlier been reported for the light tin isotopes, our result for tellurium does not show any enhanced transition probability with respect to the theoretical predictions and the tellurium systematics including the new data is successfully reproduced by state-of-the-art shell model calculations.
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36. |
- Cederwall, Bo, 1964-, et al.
(författare)
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Lifetime Measurements of Excited States in Pt-172 and the Variation of Quadrupole Transition Strength with Angular Momentum
- 2018
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 121:2
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Tidskriftsartikel (refereegranskat)abstract
- Lifetimes of the first excited 2(+) and 4(+) states in the extremely neutron -deficient nuclide Pt-172 have been measured for the first time using the recoil-distance Doppler shift and recoil-decay tagging techniques. An unusually low value of the ratio B(E2: 4(1)(+) -> 2(1)(+)/B(E2: 2(1)(+) -> 0(gs)(+)) = 0.55(19) was found, similar to a handful of other such anomalous cases observed in the entire Segre chart. The observation adds to a cluster of a few extremely neutron -deficient nuclides of the heavy transition metals with neutron numbers N approximate to 90-94 featuring the effect. No theoretical model calculations reported to date have been able to explain the anomalously low B(E2: 4(1)(+) -> 2(1)(+)/B(E2: 2(1)(+) -> 0(gs)(+)) ratios observed in these cases. Such low values cannot, e.g., be explained within the framework of the geometrical collective model or by algebraic approaches within the interacting boson model framework. It is proposed that the group of B(E2: 4(1)(+) -> 2(1)(+)/B(E2: 2(1)(+) -> 0(gs)(+)) ratios in the extremely neutron-deficient even-even W, Os, and Pt nuclei around neutron numbers N approximate to 90-94 reveal a quantum phase transition from a seniority-conserving structure to a collective regime as a function of neutron number. Although a system governed by seniority symmetry is the only theoretical framework for which such an effect may naturally occur, the phenomenon is highly unexpected for these nuclei that are not situated near closed shells.
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37. |
- 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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38. |
- 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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39. |
- 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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40. |
- 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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41. |
- 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
-
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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42. |
- Gono, Y., et al.
(författare)
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Systematics of high-spin isomers in N=83 isotones and a high-spin isomer beam
- 2002
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Ingår i: European Physical Journal A. - 1434-6001 .- 1434-601X. ; 13:02-jan, s. 5-8
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Tidskriftsartikel (refereegranskat)abstract
- Isomers in N = 83 isotones of Z = 60 66 were studied systematically. Their spins and parities arc,49/2(+) and 27(+) for odd and odd-odd nuclei, respectively. Nearly constant excitation energies of these isomers indicated a decrease of a Z = 64 shell gap energy as Z decreases from 64 to 60 within the framework of a deformed independent-particle model (DIPM). Their configurations are [v(f(tau/2)h(9/2)i(13/2)), pi(h(11/2))(2)](49/2+) and [v(f(7/2)h(9/2)i(13/2)), pi(h(11/2))(2)(d(5/2))(-1)](27+) for odd and odd-odd nuclei, respectively. The shape of the yrast status changes suddenly at spin 49/2(odd) and 27(odd-odd) from a near spherical to an oblate shape. Transitions from isomers are highly hindered because of the shape changes. They may be categorized to be shape isomers. The development of a secondary beam produced by using these high-spin isomers is also described.
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43. |
- Ideguchi, E., et al.
(författare)
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Orbifold projection in supersymmetric QCD at N(f) ≤ N(c)
- 2000
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Ingår i: Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics. - 0370-2693. ; 492:3-4, s. 369-375
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Tidskriftsartikel (refereegranskat)abstract
- Supersymmetric orbifold projection of N = 1 SQCD with relatively small number of flavors (N(f) ≤ N(c)) is considered. The purpose is to check whether orbifolding commutes with the infrared limit. On the one hand, one considers the orbifold projection of SQCD and obtains the low-energy description of the resulting theory. On the other hand, one starts with the low-energy effective theory of the original SQCD, and only then performs orbifolding. It is shown that at finite N(c) the two low-energy theories obtained in these ways are different. However, in the case of stabilized run-away vacuum these two theories are shown to coincide in the large N(c) limit. In the case of quantum modified moduli space, topological solitons carrying baryonic charges are present in the orbifolded low-energy theory. These solitons may restore the correspondence between the two theories provided that the soliton mass tends to zero in the large N(c) limit. (C) 2000 Elsevier Science B.V.
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44. |
- Ideguchi, E., et al.
(författare)
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Position sensitivity of a segmented planar Ge detector
- 2003
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier. - 0168-9002 .- 1872-9576. ; 496:03-feb, s. 373-384
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Tidskriftsartikel (refereegranskat)abstract
- A method to extract depth of interaction information for gamma-rays in a segmented planar Ge detector is presented. The method is demonstrated on signals from a segmented detector which were stored by a digital oscilloscope event by event and analysed off-line. Event samples were acquired for different interaction points in the detector. A Compton scatter coincidence detection technique ensured that the event samples were highly enriched in single-interaction events. By analysing pulse shapes and the relative timing between anode pulses and the pulses from the irradiated cathode segment, a position sensitivity of 1-2 mm in the depth direction was deduced. A similar transverse position sensitivity was inferred by studying image charge pulses on neighbouring segments.
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45. |
- Ideguchi, E., et al.
(författare)
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Study of high-spin states in 48Ca region induced by secondary fusion reactions
- 2005
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Konferensbidrag (refereegranskat)abstract
- A new method of in-beam gamma-ray spectroscopy induced by secondary fusion reactions, 37P+9Be and 46Ar+9Be is presented. Low-energy secondary beams of 37P and 46Ar ions of ∼5 MeV/A were developed in order to induce fusion evaporation reactions. Excited states of nuclei in the vicinity of 48Ca, 49-52Ti and 46Ca, were studied by the method as well as β decay of the secondary beam 46Ar. Gamma-gamma coincidence and excitation function analysis were performed to study high-spin states of Ti isotopes.
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46. |
- Ideguchi, E, et al.
(författare)
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Study of high-spin states in the Ca-48 region by using secondary fusion reactions
- 2005
-
Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 25, s. 429-430
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Tidskriftsartikel (refereegranskat)abstract
- An in-beam gamma-ray spectroscopy study, following a fusion reaction induced by a neutronrich secondary beam, Ar-46 + Be-9, is presented. A low-energy secondary beam of Ar-46 at similar to 5 MeV/A was developed in order to induce fusion reactions. Gamma-gamma coincidence and excitation function analysis was performed to study high-spin states in the vicinity of Ca-48, Ti49-52.
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47. |
- Ideguchi, E., et al.
(författare)
-
Superdeformation in the Doubly Magic Nucleus 40Ca
- 2001
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Ingår i: Physical Review Letters. - 1079-7114. ; 87:22
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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 indicates a superdeformed shape with a deformation beta (2) = 0.59(-0.07)(+0.11). The features of this band are explained by cranked relativistic mean field calculations to arise from an 8-particle 8-hole excitation.
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48. |
- 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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49. |
- 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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50. |
- Jerrestam, Dan, et al.
(författare)
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High spin bands in Pd-102
- 1996
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Ingår i: NUCLEAR PHYSICS A. - : ELSEVIER SCIENCE BV. - 0375-9474. ; 603:2, s. 203-218
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Tidskriftsartikel (refereegranskat)abstract
- The nucleus Pd-102 has been studied using 148 MeV S-34 ions impinging on Ge-76. The gamma-rays were detected with the Nordball array and the light charged particles with a 4 pi charged particle detector system. Rotational bands have been extended using ga
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