| 1. |
- Cederwall, Bo, et al.
(author)
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Evidence for a spin-aligned neutron-proton paired phase from the level structure of 92Pd
- 2011
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 469:7328, s. 68-71
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Journal article (peer-reviewed)abstract
- Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work(1) that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing(2-6), in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus Pd-92. Gamma rays emitted following the Ni-58(Ar-36,2n)Pd-92 fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution c-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction(2-6). We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling(7,8)) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis.
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| 2. |
- Hadinia, Baharak, et al.
(author)
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First identification of excited states in 106Te and evidence for isoscalar-enhanced vibrational collectivity
- 2005
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In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 72:4, s. 041303-1-041303-5
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Journal article (peer-reviewed)abstract
- Gamma-ray transitions in the extremely neutron-deficient nucleus Te-106 have been identified for the first time. The experiment utilized the Fe-54(Fe-54,2n)Te-106(*) reaction, and the gamma-ray transitions from excited states in Te-106 were selected by use of the recoil-decay-tagging technique. The production cross section was estimated at 25 nb, a new limit for in-beam gamma-ray spectroscopy. A ground-state band tentatively extending up to I-pi=10(+) is proposed. The systematics of low-lying yrast states in the Te isotopes is discussed within the context of vibrational excitations and residual nucleon-nucleon interactions.
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| 3. |
- Hadinia, Baharak, et al.
(author)
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First identification of gamma-rays in Te-106 using recoil decay tagging technique
- 2006
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In: Frontiers in Nuclear Structure Astrophysics, and Reactions: FINUSTAR. - MELVILLE, NY : AMER INST PHYSICS. - 0735403236 - 9780735403239 ; , s. 457-459
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Conference paper (peer-reviewed)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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| 4. |
- Hadinia, Baharak, et al.
(author)
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In-beam gamma-ray and alpha-decay spectroscopy of 170Ir
- 2007
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In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 76:4, s. 044312-1-044312-8
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Journal article (peer-reviewed)abstract
- Excited states in the highly neutron deficient odd-odd nucleus Ir-170 have been investigated. The experiment was performed using the Sn-112(Ni-60, pn)Ir-170 reaction and employing the recoil-decay tagging technique. Gamma rays were detected using the JUROGAM gamma-ray spectrometer and those belonging to Ir-170 were selected based on recoil identification provided by the RITU gas-filled recoil separator and the GREAT spectrometer at the RITU focal plane. A partial level scheme of Ir-170 is presented for the first time. New alpha-decay branches are assigned to Ir-170 and a tentative level structure for Re-166 is deduced from a study of the alpha-decay fine structure and the associated alpha-gamma correlations.
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| 5. |
- Sandzelius, Mikael, et al.
(author)
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First identification of excited states in 169Ir
- 2007
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In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 75:5, s. 054321-
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Journal article (peer-reviewed)abstract
- Gamma rays populating the alpha-decaying isomeric state in Ir-169 have been observed for the first time. The experiment employed the recoil-decay tagging method using the JUROGAM gamma-ray spectrometer, the RITU gas-filled recoil separator and the GREAT spectrometer located at the RITU focal plane. The gamma-ray cascade feeding the isomeric alpha-decaying state exhibits a rotational structure consistent with a h(11/2) proton coupled to a triaxially deformed core. The experimental results are compared with predictions from total Routhian surface calculations.
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| 6. |
- Al-Khatib, A., et al.
(author)
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High-spin states in Ba-124
- 2005
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In: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 36:4, s. 1029-1032
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Journal article (peer-reviewed)abstract
- High-spin states in Ba-124 were populated using the Ni-64 (Ni-64,4n) Ba-124 reaction at beam energies of 255 and 261 MeV. Gamma-ray coincidences were measured using the EUROBALL detector array. The charged-particle detector array DIAMANT provided channel selection. The previously known rotational bands are extended to higher spins. Five new hands are observed, one of them extends up to the spin 40h region.
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| 7. |
- Andgren, Karin, et al.
(author)
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Low-spin collective behavior in the transitional nuclei Mo-86,Mo-88
- 2007
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In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 76:1, s. 014307-
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Journal article (peer-reviewed)abstract
- Low-spin structures in Mo-86,Mo-88 were populated using the Ni-58(Ar-36, x alpha yp) heavy-ion fusion-evaporation reaction at a beam energy of 111 MeV. Charged particles and gamma rays were emitted in the reactions and detected by the DIAMANT CsI ball and the EXOGAM Ge array, respectively. In addition to the previously reported low-to-medium spin states in these nuclei, new low-spin structures were observed. Angular correlation and linear polarization measurements were performed in order to unambiguously determine the spins and parities of intensely populated states in Mo-88. Quasiparticle Random Phase Approximation (QRPA) calculations were performed for the first and second excited 2(+) states in Mo-86 and Mo-88. The results are in qualitative agreement with the experimental results, supporting a collective interpretation of the low-spin states for these transitional nuclei.
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| 8. |
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| 9. |
- Autio, Hanna, et al.
(author)
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Historically Based Room Acoustic Analysis and Auralization ofa Church in the 1470s
- 2021
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In: Applied Sciences. - : MDPI. - 1454-5101 .- 2076-3417. ; 11:4
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Journal article (peer-reviewed)abstract
- Worship space acoustics have been established as an important part of a nation’s cultural heritage and area of acoustic research, but more research is needed regarding the region of northern Europe. This paper describes the historical acoustics of an important abbey church in Sweden in the 1470s. A digital historical reconstruction is developed. Liturgical material specific to this location is recorded and auralized within the digital reconstruction, and a room acoustic analysis is performed. The analysis is guided by liturgical practices in the church and the monastic order connected to it. It is found that the historical sound field in the church is characterized by the existence of two distinct acoustical subspaces within it, each corresponding to a location dedicated to the daily services of the monastical congregations. The subspaces show significantly better acoustic conditions for liturgical activities compared to the nave, which is very reverberant under the conditions of daily services. Acoustic transmission from the two subspaces is limited, indicating that the monastic congregations were visually and acoustically separated from the visitors in the nave and each other.
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| 10. |
- Bygdéus, Pia, 1963-, et al.
(author)
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Legitimitet och närvaro i klostersång
- 2019
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In: Musikforskning idag 2019, Göteborgs universitet, 12–14 juni 2019. - : Svenska samfundet för musikforskning. ; , s. 12-12
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Conference paper (other academic/artistic)abstract
- 2016 initierades ett samarbete mellan benediktinklostret Mariavall och Bygdéus/Strinnholm Lagergren. De 15 nunnorna önskade förbättra sitt sångsätt och repertoaren önskades få nytt syre, förbättras och arbetas med. I denna presentation demonstreras och presenteras några av de viktigaste resultaten från detta pågående arbete utifrån frågor om förändringsprocess, praktik och repertoar där åhörarna delvis själva får delta. Uppdraget att arbeta med kommuniteten har kommit att paras med ett syfte där Bygdéus/Strinnholm Lagergren studerar hur en sjungande grupp som lever i en avskild miljö förändrar sin sångliga praxis och förändringsprocesser i den. Metoden har bestått i aktivt repetitionsarbete med kommuniteten med efterföljande reflektion, fotodokumentation och portföljskrivning. Projektet är inne på sitt tredje år med besök en gång i halvåret under tre dagar vardera. Portföljskrivning har inneburit att systrarna besvarat samma frågor i slutet av två övningstillfällen per dag under tre dagar. Portföljsvaren är individuella. Systrarnas reflektioner finns insamlat kring de många olika moment, teman och systrarnas individuella uppfattning om det gemensamma arbetet vilka sedan tematiserats. I materialbearbetningen av portföljskrivning blir särskilt följande kategorier tydliga: akustiken och rummet, upplevelsen av gemensam sång, olika attityd till sång innanför och utanför liturgin, förflyttningar, varierande uppställningar och kroppspositioner, lyssnande under sång, samtidighet i sången, rädslor. Repertoarmässigt finns en önskan sedan projektets start att sjunga mer på latin, mer gregorianik, särskilt i mässans inledande sång introitus. Allt eftersom har arbetet även kommit att omfatta andra delar av den liturgiska musiken samt sånger som inte alls används i liturgin men har sociala och sångtekniska aspekter för det individuella såväl som kollektiva arbetet med rösten och sång i grupp. Generellt framträder ett mönster där systrarna vill hitta ett personligt förhållningssätt till en tradition med lång historia utan att förlora sin egen identitet.
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| 11. |
- Bäck, Torbjörn, et al.
(author)
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First observation of gamma-rays from the proton emitter Au-171
- 2003
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In: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 16:4, s. 489-494
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Journal article (peer-reviewed)abstract
- Gamma-rays from the alpha- and proton-unstable nuclide Au-171 have been observed for the first time. The gamma-rays were correlated with both a proton- and an alpha-particle decay branch, confirming that the nucleus decays by alpha and proton emission from a single (11/2(-)) state. The measurement confirms the previously determined half-lives for these particle decays but the present values are of higher precision. In addition, a longer half-life than determined in previous work was measured for the proton-unstable tentative ground state. The results are discussed in relation to structures in neighbouring nuclei and compared with a Strutinsky-type TRS calculation.
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| 12. |
- Bäck, Torbjörn, et al.
(author)
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Spectroscopy of the neutron-deficient nuclide Pt-171
- 2003
-
In: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 17:1, s. 1-5
-
Journal article (peer-reviewed)abstract
- A number of previously unobserved gamma-rays emitted from the neutron-deficient nuclide Pt-171 have been identified using the recoil decay tagging technique. The level scheme has been updated using information from gamma-gamma coincidences and angular distribution measurements. To further confirm the assignments of the gamma-rays to Pt-171, the events were correlated with the alpha-decay of the daughter nucleus Os-167.
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| 13. |
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| 14. |
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| 15. |
- Gadea, A., et al.
(author)
-
Observation of Ni-54 : Cross-conjugate symmetry in f(7/2) mirror energy differences
- 2006
-
In: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 97:15, s. 152501-
-
Journal article (peer-reviewed)abstract
- Gamma decays from excited states up to J(pi)=6(+) in the N=Z-2 nucleus Ni-54 have been identified for the first time. Level energies are compared with those of the isobars Co-54 and Fe-54 and of the cross-conjugate nuclei of mass A=42. The good but puzzling f(7/2) cross-conjugate symmetry in mirror and triplet energy differences is analyzed. Shell model calculations reproduce the new data but the necessary nuclear charge-dependent phenomenology is not fully explained by modern nucleon-nucleon potentials.
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| 16. |
- Hadinia, Baharak, et al.
(author)
-
First identification of gamma-ray transitions in 107Te
- 2004
-
In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 70:6, s. 064314-1-064314-4
-
Journal article (peer-reviewed)abstract
- Gamma-ray transitions in Te-107 have been identified for the first time. The experiment, which utilized the recoil decay tagging technique, was performed at the accelerator laboratory of the University of Jyvaskyla, Finland. Prompt gamma rays produced in Ni-58(Cr-52,3n)Te-107(*) reactions were detected by the JUROGAM gamma-ray spectrometer. The gamma rays belonging to Te-107 were selected based on the recoil identification provided by the RITU gas-filled recoil separator and the GREAT focal plane spectrometer. A first excited state at 90 keV, tentatively of g(7/2) character, is proposed.
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| 17. |
- Herskind, B., et al.
(author)
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Charged particle feeding of hyperdeformed nuclei in the A=118-126 region
- 2006
-
In: Physica Scripta. - 0031-8949 .- 1402-4896. ; T125, s. 108-114
-
Journal article (peer-reviewed)abstract
- A breakthrough was recently obtained in the analysis of the so-called Hyper-Long-HyperDeformed (HLHD) experiment made at the EUROBALL-IV gamma-detector array (EB). The Ni-64 + Ni-64 double right arrow Ba-128* fusion reaction was studied at E-beam = 255 and 261 MeV, reaching the highest angular momentum that the compound nuclei can accommodate. To date no discrete HD rotational bands have been identified. However, rotational patterns in the form of ridge-structures in three-dimensional (3D) rotational mapped spectra are identified with dynamic moments of inertia J((2)) ranging from 71 to 111h(2) MeV-1 in 12 different nuclei selected by charged particle- and/or gamma-gating. The four nuclei, Te-118, Cs-124, Cs-125 and Xe-124 found with moment of inertia J((2)) >= 100h(2) MeV-1, are most likely hyperdeformed, the remaining nuclei with smaller values of J((2)), are considered to be superdeformed, in qualitative agreement with recent theoretical calculations.
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| 18. |
- Herskind, B., et al.
(author)
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Light charged particles as gateway to hyperdeformation
- 2007
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In: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 38:4, s. 1421-1430
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Journal article (peer-reviewed)abstract
- The Euroball-IV gamma-detector array, equipped with the ancillary charged particle detector array DIAMANT was used to study the residues of the fusion reaction Ni-64 + Ni-64 double right arrow Ba-128 at E-beam. = 255 and 261 MeV, in an attempt to reach the highest angular momentum and verify the existence of predicted hyperdeformed rotational bands. No discrete hyperdeformed bands were identified, but nevertheless a breakthrough was obtained through a systematic search for rotational ridge structures with very large moments of inertia J(2) >= 100 h(2) MeV((-1)), in agreement with theoretical predictions for hyperdeformed shapes. Evidence for hyperdeformation was obtained by charged particle + gamma-ray gating, selecting triple correlated ridge structures in the continuum of each of the nuclei, Te-118, Xe-124 and Cs-124,Cs-125. In 7 additional nuclei, rotational ridges were also identified with J(2) = 71-77h(2) MeV((-1)), which most probably correspond to superdeformed shape. The angular distributions of the emitted charged particles show an excess in forward direction over expectations from pure compound evaporation, which may indicate that in-complete fusion plays an important role in the population of very elongated shapes.
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| 19. |
- Ideguchi, E., et al.
(author)
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High-spin intruder band in In-107
- 2010
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In: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 81:3, s. 034303-
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Journal article (peer-reviewed)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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| 20. |
- Ideguchi, Eiji, et al.
(author)
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Superdeformation in 91Tc
- 2000
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In: Physics Letters B. - : Elsevier. - 0370-2693 .- 1873-2445. ; 492:3-4, s. 245-253
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Journal article (peer-reviewed)abstract
- A high-spin rotational band with 11 gamma -ray transitions has barn observed in Tc-91. The dynamical moment of inertia as well as the transition quadrupole moment of 8.1(-1.4)(+1.9) eb measured for this band show the characteristics of a superdeformed band. However, the shape is more elongated than in the neighbouring A = 80-90 superdeformed nuclei. Theoretical interpretations of the band within the cranked Strutinsky approach based on two different Woods-Saxon potential parameterisations are presented. Even though an unambiguous configuration assignment proved difficult, both calculations indicate a larger deformation and at least three additional high-N intruder orbitals occupied compared to the lighter SD nuclei. (C) 2000 Elsevier Science B.V. All rights reserved.
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| 21. |
- Joss, D. T., et al.
(author)
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Probing structural changes in the very neutron-deficient Os isotopes with recoil-decay tagging
- 2005
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In: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 31:10, s. S1593-S1598
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Journal article (peer-reviewed)abstract
- In recent years, the exploitation of the iecoil-decay tagging (RDT) technique with,large arrays of germanium detectors has revealed much information about the structure of heavy nuclei approaching the proton drip line. The yrast bands of the N <= 93 osmium isotopes have been identified in a campaign of tagging experiments using various spectrometer arrays coupled to the RITU gas-filled separator based at the University of Jyvaskyla. Trends in the yrast state excitation energies have indicated a transition from gamma-soft triaxial to near-spherical shapes with decreasing neutron number. Recent experimental results for Os-162 obtained with the JUROGAM and GREAT spectrometers also indicate the importance of configurations involving the h(9/2) neutron states as the N = Z 82 shell gaps are approached.
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| 22. |
- Joss, D. T., et al.
(author)
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Recoil decay tagging of gamma rays in the extremely neutron-deficient nucleus Os-162
- 2004
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In: Physical Review C. Nuclear Physics. - : American Physical Society. - 0556-2813 .- 1089-490X. ; 70:1
-
Journal article (peer-reviewed)abstract
- The neutron-deficient nucleus Os-162, produced in the Cd-106(Ni-58,2n) reaction, has been studied using the JUROGAM gamma-ray spectrometer in conjunction with the RITU gas-filled separator and the GREAT focal plane spectrometer. gamma-ray transitions in Os-162 have been assigned for the first time through the application of the recoil decay tagging technique. The excitation energy of the 2(+) state and the tentative energy of the 8(+) state are discussed in terms of the systematic energy trends as the N=82 shell gap is approached.
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| 23. |
- Joss, D. T., et al.
(author)
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Yrast structures in the light Pt isotopes Pt169-173
- 2005
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In: Journal of Physics G. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 31:10, s. S1715-S1718
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Journal article (peer-reviewed)abstract
- The exploitation of the recoil-decay tagging (RDT) technique has reinvigorated experimental investigations of the shape coexistence phenomenon in heavy neutron-deficient nuclei. In a recent experiment using the JUROGAM and GREAT spectrometers in conjunction with the RITU gas-filled separator, excited states have been investigated in the light platinum isotopes. In addition to extending the yrast sequences in Pt-170 and Pt-172, the first observation of excited states in the odd-N isotopes, Pt-169 and Pt-173, is reported. The bands are discussed in terms of trends in level excitation energies as a function of neutron number.
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| 24. |
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| 25. |
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