| 1. |
- Akkoyun, S., et al.
(författare)
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AGATA - Advanced GAmma Tracking Array
- 2012
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Ingår i: Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. - : Elsevier BV. - 0168-9002 .- 0167-5087 .- 1872-9576. ; 668, s. 26-58
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Tidskriftsartikel (refereegranskat)abstract
- The Advanced GAmma Tracking Array (AGATA) is a European project to develop and operate the next generation γ-ray spectrometer. AGATA is based on the technique of γ-ray energy tracking in electrically segmented high-purity germanium crystals. This technique requires the accurate determination of the energy, time and position of every interaction as a γ ray deposits its energy within the detector volume. Reconstruction of the full interaction path results in a detector with very high efficiency and excellent spectral response. The realisation of γ-ray tracking and AGATA is a result of many technical advances. These include the development of encapsulated highly segmented germanium detectors assembled in a triple cluster detector cryostat, an electronics system with fast digital sampling and a data acquisition system to process the data at a high rate. The full characterisation of the crystals was measured and compared with detector- response simulations. This enabled pulse-shape analysis algorithms, to extract energy, time and position, to be employed. In addition, tracking algorithms for event reconstruction were developed. The first phase of AGATA is now complete and operational in its first physics campaign. In the future AGATA will be moved between laboratories in Europe and operated in a series of campaigns to take advantage of the different beams and facilities available to maximise its science output. The paper reviews all the achievements made in the AGATA project including all the necessary infrastructure to operate and support the spectrometer. © 2011 Elsevier B.V. All rights reserved.
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| 2. |
- Das, P., et al.
(författare)
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Study of exotic decay of Cs isotope close to the proton drip line
- 2020
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Ingår i: 27th International Nuclear Physics Conference (INPC2019) 29 July - 2 August 2019, Glasgow, UK. - : IOP Publishing. - 1742-6588. ; 1643
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Konferensbidrag (refereegranskat)abstract
- The neutron-deficient 115Cs was produced at ISOLDE, CERN by spallation reaction using 1.4 GeV proton on LaC2 target. The exotic decay modes were studied by using a charged particle array (DSSD and pad detectors) and a γ-detector array (four Clovers) at the ISOLDE decay station (IDS). In this report, results on observed β-delayed particle emission from 115Cs, a nucleus close to proton drip line, is presented. By measuring the time distribution in the delayed proton spectrum, the half-life of the ground state of 115Cs was extracted. The obtained half-life is in agreement with previous reported value. For the first time, the p-unbound states of 115Xe, obtained by measuring beta-delayed protons from 115Cs is reported.
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| 3. |
- Stryjczyk, M., et al.
(författare)
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Decay studies of the long-lived states in Tl 186
- 2020
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Ingår i: Physical Review C. - 2469-9985. ; 102:2
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Tidskriftsartikel (refereegranskat)abstract
- Decay spectroscopy of the long-lived states in Tl186 has been performed at the ISOLDE Decay Station at ISOLDE, CERN. The α decay from the low-spin (2-) state in Tl186 was observed for the first time and a half-life of 3.4-0.4+0.5 s was determined. Based on the α-decay energy, the relative positions of the long-lived states were fixed, with the (2-) state as the ground state, the 7(+) state at 77(56) keV, and the 10(-) state at 451(56) keV. The level scheme of the internal decay of the Tl186(10(-)) state [T1/2=3.40(9) s], which was known to decay solely through emission of 374-keV γ-ray transition, was extended and a lower limit for the β-decay branching bβ>5.9(3)% was determined. The extracted retardation factors for the γ decay of the 10(-) state were compared to the available data in neighboring odd-odd thallium isotopes indicating the importance of the πd3/2 shell in the isomeric decay and significant structure differences between Tl184 and Tl186.
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| 4. |
- Banu, A, et al.
(författare)
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108Sn Studied with Intermediate-energy Coulomb Excitation
- 2005
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 72:6
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Tidskriftsartikel (refereegranskat)abstract
- The unstable neutron-deficient Sn-108 isotope has been studied in inverse kinematics by intermediate-energy Coulomb excitation using the RISING/FRS experimental setup at GSI. This is the highest Z nucleus studied so far with this method. Its reduced transition probability B (E2;0(g.s.)(+)-> 2(1)(+)) has been measured for the first time. The extracted B(E2) value of 0.230(57)e(2) b(2) has been determined relative to the known value in the stable Sn-112 isotope. The result is discussed in the framework of recent large-scale shell model calculations performed with realistic effective interactions. The roles of particle-hole excitations of the Sn-100 core and of the Z=50 shell gap for the E2 polarization are investigated.
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| 5. |
- Das, P., et al.
(författare)
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Exotic decay of 115Cs
- 2023
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Ingår i: Physical Review C. - 2469-9985. ; 108:6
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Tidskriftsartikel (refereegranskat)abstract
- The detailed study of the β+/EC decay of the very neutron-deficient and alpha-unbound nucleus 115Cs is presented. The measurement was performed at the ISOLDE, CERN where delayed charged particles and γ rays were detected. The observed delayed γ rays are in agreement with the previously reported characteristics γ rays of 115Xe. Based on the experimental observations, the tentative ground-state spin of 115Cs is suggested to be 7/2+ or 9/2+. Furthermore, the measured decay branching ratio of delayed protons exceeds the previously reported value. Additionally, new delayed α-branching ratio and several reconstructed proton and α-unbound excited states of 115Xe are being reported for the first time. The properties of proton-unbound states at excitation energies from 3.9–7.9 MeV have been obtained by fitting the delayed proton spectrum via the Bayesian method. The measured lifetimes of these proton-unbound states are in the order of zeptoseconds.
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| 6. |
- IDS Collaboration, HASH(0x3dac240), et al.
(författare)
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Beta-delayed proton emission from 20Mg
- 2016
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 52:10, s. 304-
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Tidskriftsartikel (refereegranskat)abstract
- Beta-delayed proton emission from 20 Mg has been measured at ISOLDE, CERN, with the ISOLDE Decay Station (IDS) setup including both charged-particle and gamma-ray detection capabilities. A total of 27 delayed proton branches were measured including seven so far unobserved. An updated decay scheme, including three new resonances above the proton separation energy in 20 Na and more precise resonance energies, is presented. Beta-decay feeding to two resonances above the Isobaric Analogue State (IAS) in 20 Na is observed. This may allow studies of the 4032.9(2.4)keV resonance in 19 Ne through the beta decay of 20 Mg, which is important for the astrophysically relevant reaction 15O(?,?)19Ne. Beta-delayed protons were used to obtain a more precise value for the half-life of 20 Mg, 91.4(1.0)ms.
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| 7. |
- Kirsebom, O. S., et al.
(författare)
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First Accurate Normalization of the β -delayed α Decay of N 16 and Implications for the C 12 (α,γ) O 16 Astrophysical Reaction Rate
- 2018
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Ingår i: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 121:14
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Tidskriftsartikel (refereegranskat)abstract
- Published by the American Physical Society. The C12(α,γ)O16 reaction plays a central role in astrophysics, but its cross section at energies relevant for astrophysical applications is only poorly constrained by laboratory data. The reduced α width, γ11, of the bound 1- level in O16 is particularly important to determine the cross section. The magnitude of γ11 is determined via sub-Coulomb α-transfer reactions or the β-delayed α decay of N16, but the latter approach is presently hampered by the lack of sufficiently precise data on the β-decay branching ratios. Here we report improved branching ratios for the bound 1- level [bβ,11=(5.02±0.10)×10-2] and for β-delayed α emission [bβα=(1.59±0.06)×10-5]. Our value for bβα is 33% larger than previously held, leading to a substantial increase in γ11. Our revised value for γ11 is in good agreement with the value obtained in α-transfer studies and the weighted average of the two gives a robust and precise determination of γ11, which provides significantly improved constraints on the C12(α,γ) cross section in the energy range relevant to hydrostatic He burning.
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| 8. |
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| 9. |
- Söderström, Pär-Anders, et al.
(författare)
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Spectroscopy of neutron-rich Dy-168,Dy-170 : Yrast band evolution close to the NpNn valence maximum
- 2010
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 81:3, s. 034310-
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Tidskriftsartikel (refereegranskat)abstract
- The yrast sequence of the neutron-rich dysprosium isotope Dy-168 has been studied using multinucleon transfer reactions following collisions between a 460-MeV Se-82 beam and an Er-170 target. The reaction products were identified using the PRISMA magnetic spectrometer and the gamma rays detected using the CLARA HPGe-detector array. The 2(+) and 4(+) members of the previously measured ground-state rotational band of Dy-168 have been confirmed and the yrast band extended up to 10(+). A tentative candidate for the 4(+) -> 2(+) transition in Dy-170 was also identified. The data on these nuclei and on the lighter even-even dysprosium isotopes are interpreted in terms of total Routhian surface calculations and the evolution of collectivity in the vicinity of the proton-neutron valence product maximum is discussed.
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| 10. |
- de Angelis, G., et al.
(författare)
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Coherent proton-neutron contribution to octupole correlations in the neutron-deficient Xe-114 nucleus
- 2002
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Ingår i: Physics Letters B. - 0370-2693 .- 1873-2445. ; 535:04-jan, s. 93-102
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Tidskriftsartikel (refereegranskat)abstract
- Gamma ray linear polarization and picosecond lifetimes have been measured for levels in the neutron deficient nucleus Xe-114 using the EUROBALL IV spectrometer and the Cologne plunger device. The EUCLIDES Si-ball was used to improve the reaction channel selectivity. The linear polarization results have, for the first time, unambiguously determined the electromagnetic character of the dipole transitions de-exciting the negative parity level sequence, providing clear evidence for enhanced octupole collectivity. The discovery of two E3 transitions and the measurement of the lifetimes of the states depopulated by these transitions have allowed a quantitative determination of the octupole collectivity in the A approximate to 112 mass region. The large measured B(E3) values, close to approximate to 70 W.u., are among the strongest observed hitherto and indicate a coherent proton-neutron contribution to the octupole moment.
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