| 1. |
- Marganiec, J., et al.
(författare)
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Studies of continuum states in (16) Ne using three-body correlation techniques
- 2015
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 51:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Two-proton decay of the unbound nucleus Ne-16 , produced in one-neutron knockout from a 500 MeV/u Ne-17 beam, has been studied at GSI. The ground state, at a resonance energy 1.388(15) MeV, ( MeV) above the O-14 +p+p threshold, and two narrow resonances at MeV and 7.57(6) MeV have been investigated. A comparison of the energy difference between the first excited 2(+) state and the 0(+) ground state in Ne-16 with its mirror nucleus C-16 reveals a small Thomas-Ehrman shift (TES) of keV. A trend of the TES for the T = 2 quintet is obtained by completing the known data with a prediction for F-16 obtained from an IMME analysis. The decay mechanisms of the observed three resonances were revealed from an analysis of the energy and angular correlations of the O-14 +p+p decay products. The ground state decay can be considered as a genuine three-body (democratic) mode and the excited states decay sequentially via states in the intermediate nucleus F-15 , the 3.22 MeV state predominantly via the F-15 ground-state resonance, while the 7.57 MeV state decays via the 5/2(+) resonance in F-15 at 2.8 MeV above the O-14 +p+p threshold. Further, from an analysis of angular correlations, the spin-parity of the 7.57 MeV state has been determined as and assigned as the third 2(+) state in Ne-16 based on a comparison with C-16.
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| 2. |
- Gorbinet, T., et al.
(författare)
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A sample of the results of the first SOFIA experiment
- 2015
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Ingår i: Physics Procedia. - : Elsevier BV. - 1875-3884 .- 1875-3892. ; 64, s. 101-106
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Konferensbidrag (refereegranskat)abstract
- The first SOFIA experiment (Studies On FIssion with Aladin) was performed in August 2012 at GSI. The fission of several neutron-deficient actinides and pre-actinides was induced in flight at 700 A MeV by electromagnetic excitation. The use of inverse kinematics provides both high detection and high geometrical efficiency. The complete identification of both fission fragments in coincidence (nuclear charge and mass) was obtained over a broad range of fissioning nuclei. After a short introduction and description of the experimental setup, the quality of the charge and mass separation is presented, followed by some results concerning the Coulex-induced fission of U-234 and U-235. (C) 2015 Published by Elsevier B.V.
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| 3. |
- Marganiec, J., et al.
(författare)
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Coulomb Dissociation experiment of 27P
- 2015
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Ingår i: Acta Physica Polonica, Series B.. - 1509-5770 .- 0587-4254. ; 46:3, s. 473-476
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Tidskriftsartikel (refereegranskat)abstract
- The 26Si(p; γ)27P reaction, which might play an important role in the rp process, was studied by the Coulomb Dissociation method. The experiment was performed at GSI, Darmstadt. A secondary 27P ion beam of 500 MeV/nucleon was directed onto a Pb target. From this experiment, the Coulomb Dissociation cross section, σCoulex, will be deduced and then converted to the photoabsorption cross section, σphoto, and the radiativecapture cross section, σcap. Also information on the structure of 27P will be obtained. The analysis is in progress.
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| 4. |
- Martin, J. F., et al.
(författare)
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Studies on fission with ALADIN Precise and simultaneous measurement of fission yields, total kinetic energy and total prompt neutron multiplicity at GSI
- 2015
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-601X .- 1434-6001. ; 51:12, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- A novel technique for fission studies, based on the inverse kinematics approach, is presented. Following pioneering work in the nineties, the SOFIA Collaboration has designed and built an experimental set-up dedicated to the simultaneous measurement of isotopic yields, total kinetic energies and total prompt neutron multiplicities, by fully identifying both fission fragments in coincidence, for the very first time. This experiment, performed at GSI, permits to study the fission of a wide variety of fissioning systems, ranging from mercury to neptunium, possibly far from the valley of stability. A first experiment, performed in 2012, has provided a large array of unprecedented data regarding the nuclear fission process. An excerpt of the results is presented. With this solid starter, further improvements of the experimental set-up are considered, which are consistent with the expected developments at the GSI facility, in order to measure more fission observables in coincidence. The completeness reached in the SOFIA data, permits to scrutinize the correlations between the interesting features of fission, offering a very detailed insight in this still unraveled mechanism.
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| 5. |
- Rodriguez-Sanchez, J. L., et al.
(författare)
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Complete characterization of the fission fragments produced in reactions induced by Pb 208 projectiles on proton at 500A MeV
- 2015
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Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 91:6
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Tidskriftsartikel (refereegranskat)abstract
- The two fragments produced in fission reactions induced by Pb208 projectiles impinging on a liquid hydrogen target at 500AMeV have been fully identified in coincidence. The experiment was performed at GSI Darmstadt, where the combined use of the inverse kinematics technique with an efficient detection setup permitted one to detect and to fully identify the fission fragments in a range from Z=27 to Z=52. The corresponding isotopic cross sections and velocities of the fission fragments were measured with high accuracy. The results are compared to state-of-the-art model calculations that reproduce the measured observables. Correlations between the two fragments were used to assess the role of charge polarization and the excitation energy gained by the nascent fragments using the neutron excess of the final fragments. The analysis of the average velocities of the fission fragments allowed us to parametrize the distance between the two fission fragments at scission as a function of the size of the fissioning system.
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| 6. |
- Rodriguez-Sanchez, J. L., et al.
(författare)
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Constraining the level density using fission of lead projectiles
- 2015
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Ingår i: Physical Review C - Nuclear Physics. - 2469-9985 .- 2469-9993. ; 92:4
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Tidskriftsartikel (refereegranskat)abstract
- The nuclear level density is one of the main ingredients for the statistical description of the fission process. In this work, we propose to constrain the description of this parameter by using fission reactions induced by protons and light ions on Pb208 at high kinetic energies. The experiment was performed at GSI (Darmstadt), where the combined use of the inverse kinematics technique with an efficient detection setup allowed us to measure the atomic number of the two fission fragments in coincidence. This measurement permitted us to obtain with high precision the partial fission cross sections and the width of the charge distribution as a function of the atomic number of the fissioning system. These data and others previously measured, covering a large range in fissility, are compared to state-of-the-art calculations. The results reveal that total and partial fission cross sections cannot unambiguously constrain the level density at ground-state and saddle-point deformations and additional observables, such as the width of the charge distribution of the final fission fragments, are required.
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| 7. |
- Rodriguez-Sanchez, J. L., et al.
(författare)
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Transient effects in fission investigated with proton-on-lead reactions in complete kinematic measurements
- 2015
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Ingår i: Physics Procedia. - : Elsevier BV. - 1875-3884 .- 1875-3892. ; 64, s. 157-162
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Konferensbidrag (refereegranskat)abstract
- Proton-induced fission of Pb-208 has been investigated at 370, 500 and 650 A MeV in complete kinematic measurements. The experiment was performed at GSI Darmstadt where the combined use of the inverse kinematics technique with an efficient detection setup allowed to measure for the first time the atomic and mass number of both fission fragments. The performed measurement together with different model calculations allow us to investigate dissipative and transient effects in the fission process and the dependence on temperature and deformation of the dissipation strength beta. The use of spallation reactions with lead projectiles favours this study due to its high excitation energy and low angular momentum. (C) 2015 The Authors. Published by Elsevier B.V.
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