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Ray A, Sikdar AK, Pandit D, Bhattacharyya S, Bhattacharya S, De A, Paul S, Chatterjee A. Direct observation of slow fission from the width of K x-ray line. EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201819304004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
An atomic clock based on the measurement of the intrinsic width of K x-ray lines has been used to obtain evidence of long-lived fission of the highly excited plutonium nuclei produced in the fusion of 4He+238U at E(4He)Lab=60 MeV. The mean fission time of the long-lived fission could be obtained from the increase of the intrinsic width of plutonium K x-ray line using quantum energy-time uncertainty principle. The presence of long-lived fission (mean fission time >1×10-18 s) has been found and the fluorescence yield per fission event shows that most of the fission events are slow (~10-18 s).
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Andreyev AN, Nishio K, Schmidt KH. Nuclear fission: a review of experimental advances and phenomenology. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2018; 81:016301. [PMID: 28753131 DOI: 10.1088/1361-6633/aa82eb] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In the last two decades, through technological, experimental and theoretical advances, the situation in experimental fission studies has changed dramatically. With the use of advanced production and detection techniques both much more detailed and precise information can now be obtained for the traditional regions of fission research and, crucially, new regions of nuclei have become routinely accessible for fission studies. This work first of all reviews the recent developments in experimental fission techniques, in particular the resurgence of transfer-induced fission reactions with light and heavy ions, the emerging use of inverse-kinematic approaches, both at Coulomb and relativistic energies, and of fission studies with radioactive beams. The emphasis on the fission-fragment mass and charge distributions will be made in this work, though some of the other fission observables, such as prompt neutron and γ-ray emission will also be reviewed. A particular attention will be given to the low-energy fission in the so far scarcely explored nuclei in the very neutron-deficient lead region. They recently became the focus for several complementary experimental studies, such as β-delayed fission with radioactive beams at ISOLDE(CERN), Coulex-induced fission of relativistic secondary beams at FRS(GSI), and several prompt fusion-fission studies. The synergy of these approaches allows a unique insight in the new region of asymmetric fission around [Formula: see text]Hg, recently discovered at ISOLDE. Recent extensive theoretical efforts in this region will also be outlined. The unprecedented high-quality data for fission fragments, completely identified in Z and A, by means of reactions in inverse kinematics at FRS(GSI) and VAMOS(GANIL) will be also reviewed. These experiments explored an extended range of mercury-to-californium elements, spanning from the neutron-deficient to neutron-rich nuclides, and covering both asymmetric, symmetric and transitional fission regions. Some aspects of heavy-ion induced fusion-fission and quasifission reactions will be also discussed, which reveal their dynamical features, such as the fission time scale. The crucial role of the multi-chance fission, probed by means of multinucleon-transfer induced fission reactions, will be highlighted. The review will conclude with the discussion of the new experimental fission facilities which are presently being brought into operation, along with promising 'next-generation' fission approaches, which might become available within the next decade.
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Affiliation(s)
- A N Andreyev
- Department of Physics, University of York, York, YO10 5DD, United Kingdom. Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
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Morjean M, Hinde DJ, Simenel C, Jeung DY, Airiau M, Cook KJ, Dasgupta M, Drouart A, Jacquet D, Kalkal S, Palshetkar CS, Prasad E, Rafferty D, Simpson EC, Tassan-Got L, Vo-Phuoc K, Williams E. Evidence for the Role of Proton Shell Closure in Quasifission Reactions from X-Ray Fluorescence of Mass-Identified Fragments. PHYSICAL REVIEW LETTERS 2017; 119:222502. [PMID: 29286775 DOI: 10.1103/physrevlett.119.222502] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Indexed: 06/07/2023]
Abstract
The atomic numbers and the masses of fragments formed in quasifission reactions are simultaneously measured at scission in ^{48}Ti+^{238}U reactions at a laboratory energy of 286 MeV. The atomic numbers are determined from measured characteristic fluorescence x rays, whereas the masses are obtained from the emission angles and times of flight of the two emerging fragments. For the first time, thanks to this full identification of the quasifission fragments on a broad angular range, the important role of the proton shell closure at Z=82 is evidenced by the associated maximum production yield, a maximum predicted by time-dependent Hartree-Fock calculations. This new experimental approach gives now access to precise studies of the time dependence of the N/Z (neutron over proton ratios of the fragments) evolution in quasifission reactions.
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Affiliation(s)
- M Morjean
- GANIL, CEA/DRF and CNRS/IN2P3, B.P. 55027, F-14076 Caen Cedex, France
| | - D J Hinde
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 0200, Australia
| | - C Simenel
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 0200, Australia
| | - D Y Jeung
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 0200, Australia
| | - M Airiau
- Institut de Physique Nucléaire, CNRS-IN2P3, Université Paris-Sud, Université Paris-Saclay, F-91406 Orsay Cedex, France
- Irfu, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - K J Cook
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 0200, Australia
| | - M Dasgupta
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 0200, Australia
| | - A Drouart
- Irfu, CEA, Université Paris-Saclay, F-91191 Gif-sur-Yvette, France
| | - D Jacquet
- Institut de Physique Nucléaire, CNRS-IN2P3, Université Paris-Sud, Université Paris-Saclay, F-91406 Orsay Cedex, France
| | - S Kalkal
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 0200, Australia
| | - C S Palshetkar
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 0200, Australia
| | - E Prasad
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 0200, Australia
| | - D Rafferty
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 0200, Australia
| | - E C Simpson
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 0200, Australia
| | - L Tassan-Got
- Institut de Physique Nucléaire, CNRS-IN2P3, Université Paris-Sud, Université Paris-Saclay, F-91406 Orsay Cedex, France
| | - K Vo-Phuoc
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 0200, Australia
| | - E Williams
- Department of Nuclear Physics, Research School of Physics and Engineering, The Australian National University, ACT 0200, Australia
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Hinde D, Williams E, du Rietz R, Dasgupta M, Wakhle A, Simenel C, Luong D, Cook K. Mapping quasifission characteristics in heavy element formation reactions. EPJ WEB OF CONFERENCES 2015. [DOI: 10.1051/epjconf/20158600015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Wakhle A, Simenel C, Hinde DJ, Dasgupta M, Evers M, Luong DH, du Rietz R, Williams E. Interplay between quantum shells and orientation in quasifission. PHYSICAL REVIEW LETTERS 2014; 113:182502. [PMID: 25396364 DOI: 10.1103/physrevlett.113.182502] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Indexed: 06/04/2023]
Abstract
The quasifission mechanism hinders fusion in heavy systems through breakup within zeptoseconds into two fragments with partial mass equilibration. Its dependence on the structure of both the collision partners and the final fragments is a key question. Our original approach is to combine an experimental measurement of the fragments' mass-angle correlations in (40)Ca+(238)U with microscopic quantum calculations. We demonstrate an unexpected interplay between the orientation of the prolate deformed (238)U with quantum shell effects in the fragments. In particular, calculations show that only collisions with the tip of (238)U produce quasifission fragments in the magic Z=82 region, while collisions with the side are the only ones that may result in fusion.
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Affiliation(s)
- A Wakhle
- Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - C Simenel
- Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - D J Hinde
- Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - M Dasgupta
- Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - M Evers
- Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - D H Luong
- Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - R du Rietz
- Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - E Williams
- Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 2601, Australia
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Morjean M, Chbihi A, Dasgupta M, Drouart A, Frankland J, Frégeau J, Hinde D, Jacquet D, Nalpas L, Pârlog M, Simenel C, Tassan-Got L, Williams E. Long lifetime components in the decay of excited super-heavy nuclei. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20136302011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Simenel C, Dasgupta M, Hinde DJ, Kheifets A, Wakhle A. Probing quantum many-body dynamics in nuclear systems. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20136302001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Hinde DJ, Dasgupta M, Carter I, Cook K, Evers M, Luong D, Ramachandran K, Rafferty D, Simenel C, Wakhle A, Williams E. Nuclear Reaction Dynamics Research at the Australian National University. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20136302005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Simenel C, Wakhle A, Avez B, Hinde DJ, Rietz RD, Dasgupta M, Evers M, Lin CJ, Luong DH. Effects of nuclear structure on quasi-fission. EPJ WEB OF CONFERENCES 2012. [DOI: 10.1051/epjconf/20123809001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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