| 1. |
- Brown, K. W., et al.
(författare)
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Observation of Long-Range Three-Body Coulomb Effects in the Decay of Ne-16
- 2014
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 113:23, s. Art. no. 232501-
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Tidskriftsartikel (refereegranskat)abstract
- The interaction of an E/A = 57.6-MeV Ne-17 beam with a Be target is used to populate levels in Ne-16 following neutron knockout reactions. The decay of 16Ne states into the three-body O-14 + p + p continuum is observed in the High Resolution Array (HiRA). For the first time for a 2p emitter, correlations between the momenta of the three decay products are measured with sufficient resolution and statistics to allow for an unambiguous demonstration of their dependence on the long-range nature of the Coulomb interaction. Contrary to previous measurements, our measured limit Gamma
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| 2. |
- Andreyev, A. N., et al.
(författare)
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α decay of the neutron-deficient isotope 190At
- 2023
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Ingår i: Physical Review C. - 2469-9985. ; 108:3
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Tidskriftsartikel (refereegranskat)abstract
- The α decay of the neutron-deficient 190At isotope was observed following the 103Rh(90Zr,3n)190At reaction at Argonne National Laboratory. The reaction products were separated from the beam using the Argonne Gas-Filled Analyzer and implanted into a double-sided Si strip detector. The spatial and temporal correlations between implanted nuclei and subsequent α decays towards the known daughter isotope 186Bi were used to identify and characterize 190At nuclei. Two possible decay scenarios are proposed for the 190At→186Bi decay.
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| 3. |
- 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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| 4. |
- Fischer, S M, et al.
(författare)
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Alignment additivity in the two-quasiparticle superdeformed bands of Tl-192
- 1996
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 53:5, s. 2126-2133
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Tidskriftsartikel (refereegranskat)abstract
- Four superdeformed bands have been confirmed in Tl-192. Two of these bands have T-(2) dynamic moments of inertia which are nearly constant with rotational frequency HBAR omega. The other two bands show the characteristic rise of T-(2) with increasing HBAR omega seen in most superdeformed bands of the A = 190 region of superdeformation. From comparisons with the odd-A neighbors, it was found that the alignments of these bands relative to a Hg-192 core can be accounted for from the additive contributions of the assigned quasiproton and quasineutron orbitals.
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| 5. |
- Lerma, F., et al.
(författare)
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Superdeformed bands in Sr80-83, Y82-84, Zr-83,Zr-84 : Transition quadrupole moments, moments of inertia, and configuration assignments
- 2003
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 67:4, s. 044310-
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Tidskriftsartikel (refereegranskat)abstract
- Multiple superdeformed bands in the nuclei Sr80-83, Y82-84, and Zr-83,Zr-84 have been studied in a backed-target experiment, using the Gammasphere and the Microball 4pi detector arrays. For 15 bands in these nuclei, average transition quadrupole moments have been measured with high accuracy, using the Doppler-shift attenuation method. Among these are the newly observed superdeformed bands in Y-83,Y-84, which are isospectral with the bands in Sr-82,Sr-83. These isospectral bands have nearly identical transition quadrupole moments. Two of the bands in Sr-81 interact and cross transitions between them are observed. The present measurements place stringent conditions on configuration assignments for the bands obtained from two types of mean-field calculations, leading to a consistent understanding of the mass similar to80 superdeformed bands. The assignments for different bands arise from one or more nucleons occupying the N-0=5h(11/2) intruder orbital.
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| 6. |
- Andersson, Lise-Lotte, et al.
(författare)
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Comprehensive Gamma-ray Spectroscopy of Rotational Bands in the N=Z+1 Nucleus 61Zn
- 2009
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 79:2
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Tidskriftsartikel (refereegranskat)abstract
- The Zn-61(30)31 nucleus has been studied via the combined data of two fusion-evaporation reaction experiments using a Ar-36 beam and a Si-28 target foil. The experimental setups involved the Ge array GAMMASPHERE and neutron and charged particle detectors placed around the target position. The resulting level scheme comprises about 120 excited states connected via some 180 gamma-ray transitions. In total, seven rotational structures were identified up to I similar to 25 or higher and compared with predictions from cranked Nilsson-Strutinsky calculations.
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| 7. |
- Andersson, Lise-Lotte, et al.
(författare)
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Extensive Gamma-ray Spectroscopy of Normally and Superdeformed Structures in 61Cu
- 2008
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - : Springer Science and Business Media LLC. - 1434-6001. ; 36:3, s. 251-278
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Tidskriftsartikel (refereegranskat)abstract
- A largely extended experimental knowledge of the Cu-61(29)32 nucleus has been obtained from three experiments. Excited states in Cu-61 were produced via the fusion-evaporation reaction Si-28(Ar-36, 3p)Cu-61. In addition to the Ge array GAMMASPHERE, neutron and charged-particle detectors placed around the target position were used for high-performance particle spectroscopy. The constructed level scheme includes more than 160 energy levels and 320 gamma-ray transitions belonging to both normally deformed as well as superdeformed rotational structures. The multipolarities have been determined for the gamma-ray transitions and as a result spin-parity assignments are given for nearly all energy levels. Experimental results in the normally deformed region are compared with predictions from large-scale shell model calculations. The collective structures are compared with results from cranked Nilsson-Strutinsky calculations. The results reveal the need to modify the standard Nilsson parameters in the mass A similar to 60 region.
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| 8. |
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| 9. |
- 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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| 10. |
- 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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| 11. |
- 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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| 12. |
- 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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| 13. |
- 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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| 14. |
- Ekman, Jörgen, et al.
(författare)
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The A=51 Mirror Nuclei 51Fe and 51Mn
- 2000
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Ingår i: European Physical Journal A. Hadrons and Nuclei. - 1434-6001. ; 9, s. 13-17
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Tidskriftsartikel (refereegranskat)abstract
- Eighteen previously unknown gamma -ray transitions were identified in the T-z = -1/2 nucleus Fe-51 following the fusion-evaporation reaction S-32(Si-28,2 alpha 1n)Fe-51. The lever scheme reaches the fully aligned I-pi = 27/2(-) terminating state of the five holes in the f(7/2) shell. The 17/2(-) state was found to be isomeric, and the lifetime was measured to be 2.87 ns. The mirror symmetry of Fe-51 and Mn-51 is discussed, and the level scheme of Fe-51 is compared to shell-model calculations.
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| 15. |
- Gellanki, Jnaneswari, et al.
(författare)
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Characterization of Superdeformed Bands in 62Zn
- 2009
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 80:5
-
Tidskriftsartikel (refereegranskat)abstract
- Combined data from four fusion-evaporation reaction experiments were utilized to investigate deformed and superdeformed structures in Zn-62(30)32. Combination of the Gammasphere gamma-ray spectrometer and ancillary particle detection systems allowed for the connection of rotational bands to well-known, low-lying excited states in Zn-62, as well as spectroscopy of discrete high-spin states reaching excitation energies of E-x=42.5 MeV. Four well- or superdeformed bands in Zn-62 are characterized and described by means of cranked Nilsson-Strutinsky calculations.
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| 16. |
- Gellanki, Jnaneswari, et al.
(författare)
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Extensive Gamma-ray Spectroscopy of Band Structures in 62Zn
- 2012
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 86:3
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Tidskriftsartikel (refereegranskat)abstract
- An experimental study of the Zn-62 nucleus has been performed by combining the data sets from four fusion-evaporation reaction experiments. Apart from the previously published data, the present results include ten new rotational band structures and two more superdeformed bands. The Gammasphere Ge-detector array in conjunction with the 4 pi charged-particle detector array Microball allowed for the detection of gamma rays in coincidence with evaporated light particles. The deduced level scheme includes some 260 excited states, which are connected with more than 450 gamma-ray transitions. Spins and parities of the excited states have been determined via directional correlations of. rays emitted from oriented states. The experimental characteristics of the rotational bands are analyzed and compared with results from cranked Nilsson-Strutinsky calculations. The present analysis, combined with available experimental results in the A similar to 60 mass region, can be used to improve the current set of Nilsson parameters in the N = 3 and N = 4 oscillator shells.
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| 17. |
- Gellanki, Jnaneswari, et al.
(författare)
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High-spin Structure Studies in 62Zn
- 2012
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Ingår i: Physica Scripta. - 0031-8949. ; T150
-
Tidskriftsartikel (refereegranskat)abstract
- A detailed experimental study of the Zn-62 nucleus was conducted by combining the data sets from four fusion-evaporation reaction experiments. Apart from the previous published data, the present results include ten new rotational band structures and two new superdeformed bands. The GAMMASPHERE Ge-detector array in conjunction with the 4 pi charged-particle detector array Microball allowed for detection of gamma-rays in coincidence with evaporated light particles. The deduced level scheme includes some 260 excited states, which are connected with 450 gamma-ray transitions. The multipolarities have been assigned via directional correlations of gamma-rays emitted from oriented states. The experimental characteristics of the rotational bands are analyzed and compared with the results from the cranked Nilsson-Strutinsky calculations.
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| 18. |
- Ideguchi, E., et al.
(författare)
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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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| 19. |
- 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-
-
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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| 20. |
- 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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| 21. |
- Johansson, Emma, et al.
(författare)
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Prompt Proton Decay and Deformed Bands in 56Ni
- 2008
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 77:6
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Tidskriftsartikel (refereegranskat)abstract
- High-spin states in the doubly magic N=Z nucleus Ni-56 have been investigated with three fusion-evaporation reaction experiments. New gamma-ray transitions are added, and a confirmation of a previously suggested prompt proton decay from a rotational band in Ni-56 into the ground state of Co-55 is presented. The rotational bands in Ni-56 are discussed within the framework of cranked Nilsson-Strutinsky calculations.
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| 22. |
- Johansson, Emma, et al.
(författare)
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Prompt Proton Decay in the Vicinity of 56Ni
- 2007
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Ingår i: Proton Emitting Nuclei and Related Topics. - : AIP. - 1551-7616 .- 0094-243X. ; 961, s. 41-46
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Konferensbidrag (refereegranskat)abstract
- A new decay mode, the so called prompt proton decay, was discovered in 1998. It has since proven to be an important decay mechanism for several neutron deficient nuclei in the A similar to 60 region. To measure with high accuracy the energies and angular distributions of these protons, a state-of-the-art charged particle detector - LuWuSiA - was developed. It was first utilized during a fusion-evaporation reaction experiment performed at Argonne National Laboratory, U.S.A. In this contribution, the characteristics of the prompt proton decay are discussed along with the special features of LuWuSiA as well as a revisit to the prompt proton decay in Cu-58.
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| 23. |
- Johansson, Emma, et al.
(författare)
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Thorough Gamma-ray and Particle Decay Investigations of 58Ni
- 2009
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 80:1
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Tidskriftsartikel (refereegranskat)abstract
- The combined data from three fusion-evaporation reaction experiments have been utilized to investigate the semi-magic nucleus Ni-58(28)30. To detect gamma rays in coincidence with evaporated particles, the Ge-detector array Gammasphere was used in conjunction with the charged-particle detectors Microball and LuWuSiA (the Lund Washington University Silicon Array), and a neutron detector array. The results yield a significantly extended level scheme of Ni-58 comprising some 340 gamma-ray transitions and include a total of at least 14 discrete particle decays into excited states of the daughter nuclei Fe-54 and Co-57. The level scheme is compared with large-scale shell-model calculations and cranked Nilsson-Strutinsky calculations.
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| 24. |
- 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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| 25. |
- Reviol, W, et al.
(författare)
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Highly Deformed Band Structure in 57Co
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 65
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Tidskriftsartikel (refereegranskat)abstract
- Rotational bands have been found in 57Co using the 28Si(32S,3p) reaction at 130 MeV. The bands, extending the mass 60 region of large deformation down to Z=27, are signature-partner sequences. Their quadrupole moments are similar to those of bands in the neighboring nuclei. The features of the new bands are described by Skyrme Hartree-Fock calculations favoring a configuration assignment with one neutron and one proton excited in the respective 1g9/2 intruder orbital. An attempt to describe the magnetic (M1) properties of the signature-partner structure is also presented.
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