1
|
Cubiss JG, Andreyev AN, Barzakh AE, Van Duppen P, Hilaire S, Péru S, Goriely S, Al Monthery M, Althubiti NA, Andel B, Antalic S, Atanasov D, Blaum K, Cocolios TE, Day Goodacre T, de Roubin A, Farooq-Smith GJ, Fedorov DV, Fedosseev VN, Fink DA, Gaffney LP, Ghys L, Harding RD, Huyse M, Imai N, Joss DT, Kreim S, Lunney D, Lynch KM, Manea V, Marsh BA, Martinez Palenzuela Y, Molkanov PL, Neidherr D, O'Neill GG, Page RD, Prosnyak SD, Rosenbusch M, Rossel RE, Rothe S, Schweikhard L, Seliverstov MD, Sels S, Skripnikov LV, Stott A, Van Beveren C, Verstraelen E, Welker A, Wienholtz F, Wolf RN, Zuber K. Deformation versus Sphericity in the Ground States of the Lightest Gold Isotopes. PHYSICAL REVIEW LETTERS 2023; 131:202501. [PMID: 38039485 DOI: 10.1103/physrevlett.131.202501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 08/02/2023] [Accepted: 09/18/2023] [Indexed: 12/03/2023]
Abstract
The changes in mean-squared charge radii of neutron-deficient gold nuclei have been determined using the in-source, resonance-ionization laser spectroscopy technique, at the ISOLDE facility (CERN). From these new data, nuclear deformations are inferred, revealing a competition between deformed and spherical configurations. The isotopes ^{180,181,182}Au are observed to possess well-deformed ground states and, when moving to lighter masses, a sudden transition to near-spherical shapes is seen in the extremely neutron-deficient nuclides, ^{176,177,179}Au. A case of shape coexistence and shape staggering is identified in ^{178}Au which has a ground and isomeric state with different deformations. These new data reveal a pattern in ground-state deformation unique to the gold isotopes, whereby, when moving from the heavy to light masses, a plateau of well-deformed isotopes exists around the neutron midshell, flanked by near-spherical shapes in the heavier and lighter isotopes-a trend hitherto unseen elsewhere in the nuclear chart. The experimental charge radii are compared to those from Hartree-Fock-Bogoliubov calculations using the D1M Gogny interaction and configuration mixing between states of different deformation. The calculations are constrained by the known spins, parities, and magnetic moments of the ground states in gold nuclei and show a good agreement with the experimental results.
Collapse
Affiliation(s)
- J G Cubiss
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, United Kingdom
| | - A N Andreyev
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, United Kingdom
- Advanced Science Research Center (ASRC), Japan Atomic Energy Agency, Tokai-mura, Japan
| | - A E Barzakh
- Affiliated with an institute covered by a cooperation agreement with CERN
| | - P Van Duppen
- KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium
| | - S Hilaire
- Université Paris-Saclay, CEA, LMCE, 91680, Bruyères-le-Châtel, France
| | - S Péru
- Université Paris-Saclay, CEA, LMCE, 91680, Bruyères-le-Châtel, France
| | - S Goriely
- Institut d'Astronomie et d'Astrophysique, CP-226, Université Libre de Bruxelles, 1050 Brussels, Belgium
| | - M Al Monthery
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, United Kingdom
| | - N A Althubiti
- The University of Manchester, Department of Physics and Astronomy, Oxford Road, M13 9PL Manchester, United Kingdom
- Physics Department, College of Science, Jouf University, Sakakah, Kingdom of Saudi Arabia
| | - B Andel
- Department of Nuclear Physics and Biophysics, Comenius University in Bratislava, 84248 Bratislava, Slovakia
| | - S Antalic
- Department of Nuclear Physics and Biophysics, Comenius University in Bratislava, 84248 Bratislava, Slovakia
| | - D Atanasov
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
- CERN, 1211, Geneva 23, Switzerland
| | - K Blaum
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - T E Cocolios
- KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium
- The University of Manchester, Department of Physics and Astronomy, Oxford Road, M13 9PL Manchester, United Kingdom
| | - T Day Goodacre
- The University of Manchester, Department of Physics and Astronomy, Oxford Road, M13 9PL Manchester, United Kingdom
- CERN, 1211, Geneva 23, Switzerland
| | - A de Roubin
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - G J Farooq-Smith
- KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium
- The University of Manchester, Department of Physics and Astronomy, Oxford Road, M13 9PL Manchester, United Kingdom
| | - D V Fedorov
- Affiliated with an institute covered by a cooperation agreement with CERN
| | | | - D A Fink
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
- CERN, 1211, Geneva 23, Switzerland
| | - L P Gaffney
- KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium
- CERN, 1211, Geneva 23, Switzerland
| | - L Ghys
- KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium
| | - R D Harding
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, United Kingdom
- CERN, 1211, Geneva 23, Switzerland
| | - M Huyse
- KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium
| | - N Imai
- Center for Nuclear Study (CNS), Graduate School of Science The University of Tokyo, Japan
| | - D T Joss
- Department of Physics, University of Liverpool, Liverpool, L69 7ZE, United Kingdom
| | - S Kreim
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
- CERN, 1211, Geneva 23, Switzerland
| | - D Lunney
- CSNSM-CNRS, Université de Paris Sud, 91400 Orsay, France
| | - K M Lynch
- The University of Manchester, Department of Physics and Astronomy, Oxford Road, M13 9PL Manchester, United Kingdom
- CERN, 1211, Geneva 23, Switzerland
| | - V Manea
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | | | - Y Martinez Palenzuela
- KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium
- CERN, 1211, Geneva 23, Switzerland
| | - P L Molkanov
- Affiliated with an institute covered by a cooperation agreement with CERN
| | - D Neidherr
- GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt 64291, Germany
| | - G G O'Neill
- Department of Physics, University of Liverpool, Liverpool, L69 7ZE, United Kingdom
| | - R D Page
- Department of Physics, University of Liverpool, Liverpool, L69 7ZE, United Kingdom
| | - S D Prosnyak
- Affiliated with an institute covered by a cooperation agreement with CERN
| | - M Rosenbusch
- Institut für Physik, Universität Greifswald, 17487 Greifswald, Germany
| | - R E Rossel
- CERN, 1211, Geneva 23, Switzerland
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Mainz, D-55128, Germany
| | - S Rothe
- CERN, 1211, Geneva 23, Switzerland
- Institut für Physik, Johannes Gutenberg-Universität Mainz, Mainz, D-55128, Germany
| | - L Schweikhard
- Institut für Physik, Universität Greifswald, 17487 Greifswald, Germany
| | - M D Seliverstov
- Affiliated with an institute covered by a cooperation agreement with CERN
| | - S Sels
- KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium
| | - L V Skripnikov
- Affiliated with an institute covered by a cooperation agreement with CERN
| | - A Stott
- School of Physics, Engineering and Technology, University of York, York, YO10 5DD, United Kingdom
| | - C Van Beveren
- KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium
| | - E Verstraelen
- KU Leuven, Instituut voor Kern- en Stralingsfysica, 3001 Leuven, Belgium
| | - A Welker
- CERN, 1211, Geneva 23, Switzerland
- Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Dresden 01069, Germany
| | - F Wienholtz
- CERN, 1211, Geneva 23, Switzerland
- Institut für Physik, Universität Greifswald, 17487 Greifswald, Germany
| | - R N Wolf
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
- Institut für Physik, Universität Greifswald, 17487 Greifswald, Germany
| | - K Zuber
- Institut für Kern- und Teilchenphysik, Technische Universität Dresden, Dresden 01069, Germany
| |
Collapse
|
2
|
Schmitt C, Lemasson A, Schmidt KH, Jhingan A, Biswas S, Kim YH, Ramos D, Andreyev AN, Curien D, Ciemala M, Clément E, Dorvaux O, De Canditiis B, Didierjean F, Duchêne G, Dudouet J, Frankland J, Jacquot B, Raison C, Ralet D, Retailleau BM, Stuttgé L, Tsekhanovich I. Experimental Evidence for Common Driving Effects in Low-Energy Fission from Sublead to Actinides. PHYSICAL REVIEW LETTERS 2021; 126:132502. [PMID: 33861122 DOI: 10.1103/physrevlett.126.132502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 10/22/2020] [Accepted: 02/25/2021] [Indexed: 06/12/2023]
Abstract
Isotopic distributions of fragments from fission of the neutron-deficient ^{178}Hg nuclide are reported. This experimental observable is obtained for the first time in the region around lead using an innovative approach based on inverse kinematics and the coincidence between the large acceptance magnetic spectrometer VAMOS++ and a new detection arm close to the target. The average fragment N/Z ratio and prompt neutron M_{n} multiplicity are derived and compared with current knowledge from actinide fission. A striking consistency emerges, revealing the unexpected dominant role of the proton subsystem with atomic number between the Z=28 and 50 magic numbers. The origin of nuclear charge polarization in fission and fragment deformation at scission are discussed.
Collapse
Affiliation(s)
- C Schmitt
- Institut Pluridisciplinaire Hubert Curien, CNRS/IN2P3-UDS, 67037 Strasbourg Cedex 2, France
| | - A Lemasson
- GANIL, CEA/DRF-CNRS/IN2P3, BP 55027, 14076 Caen cedex 5, France
| | | | - A Jhingan
- Inter University Accelerator Centre, Aruna Asaf Ali Marg, Post Box 10502, New Delhi 110067, India
| | - S Biswas
- GANIL, CEA/DRF-CNRS/IN2P3, BP 55027, 14076 Caen cedex 5, France
| | - Y H Kim
- Institut Laue-Langevin, 38042 Grenoble Cedex 9, France
| | - D Ramos
- GANIL, CEA/DRF-CNRS/IN2P3, BP 55027, 14076 Caen cedex 5, France
| | - 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
- ISOLDE, CERN, CH-1211 Geneve 23, Switzerland
| | - D Curien
- Institut Pluridisciplinaire Hubert Curien, CNRS/IN2P3-UDS, 67037 Strasbourg Cedex 2, France
| | - M Ciemala
- The Niewodniczanski Institute of Nuclear Physics-PAN, 31-342 Kraków, Poland
| | - E Clément
- GANIL, CEA/DRF-CNRS/IN2P3, BP 55027, 14076 Caen cedex 5, France
| | - O Dorvaux
- Institut Pluridisciplinaire Hubert Curien, CNRS/IN2P3-UDS, 67037 Strasbourg Cedex 2, France
| | - B De Canditiis
- Institut Pluridisciplinaire Hubert Curien, CNRS/IN2P3-UDS, 67037 Strasbourg Cedex 2, France
| | - F Didierjean
- Institut Pluridisciplinaire Hubert Curien, CNRS/IN2P3-UDS, 67037 Strasbourg Cedex 2, France
| | - G Duchêne
- Institut Pluridisciplinaire Hubert Curien, CNRS/IN2P3-UDS, 67037 Strasbourg Cedex 2, France
| | - J Dudouet
- CSNSM, Université Paris-Sud, CNRS/IN2P3, Université Paris-Saclay, 91405 Orsay, France
- Université Lyon, Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, F-69622 Villeurbanne, France
| | - J Frankland
- GANIL, CEA/DRF-CNRS/IN2P3, BP 55027, 14076 Caen cedex 5, France
| | - B Jacquot
- GANIL, CEA/DRF-CNRS/IN2P3, BP 55027, 14076 Caen cedex 5, France
| | - C Raison
- Department of Physics, University of York, York YO10 5DD, United Kingdom
| | - D Ralet
- GANIL, CEA/DRF-CNRS/IN2P3, BP 55027, 14076 Caen cedex 5, France
| | - B-M Retailleau
- GANIL, CEA/DRF-CNRS/IN2P3, BP 55027, 14076 Caen cedex 5, France
| | - L Stuttgé
- Université Lyon, Université Claude Bernard Lyon 1, CNRS/IN2P3, IP2I Lyon, UMR 5822, F-69622 Villeurbanne, France
| | - I Tsekhanovich
- Université Bordeaux, CNRS, CENBG, UMR 5797, F-33170 Gradignan, France
| |
Collapse
|
3
|
Wilson JN, Thisse D, Lebois M, Jovančević N, Gjestvang D, Canavan R, Rudigier M, Étasse D, Gerst RB, Gaudefroy L, Adamska E, Adsley P, Algora A, Babo M, Belvedere K, Benito J, Benzoni G, Blazhev A, Boso A, Bottoni S, Bunce M, Chakma R, Cieplicka-Oryńczak N, Courtin S, Cortés ML, Davies P, Delafosse C, Fallot M, Fornal B, Fraile L, Gottardo A, Guadilla V, Häfner G, Hauschild K, Heine M, Henrich C, Homm I, Ibrahim F, Iskra ŁW, Ivanov P, Jazrawi S, Korgul A, Koseoglou P, Kröll T, Kurtukian-Nieto T, Le Meur L, Leoni S, Ljungvall J, Lopez-Martens A, Lozeva R, Matea I, Miernik K, Nemer J, Oberstedt S, Paulsen W, Piersa M, Popovitch Y, Porzio C, Qi L, Ralet D, Regan PH, Rezynkina K, Sánchez-Tembleque V, Siem S, Schmitt C, Söderström PA, Sürder C, Tocabens G, Vedia V, Verney D, Warr N, Wasilewska B, Wiederhold J, Yavahchova M, Zeiser F, Ziliani S. Angular momentum generation in nuclear fission. Nature 2021; 590:566-570. [PMID: 33627809 DOI: 10.1038/s41586-021-03304-w] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 12/09/2020] [Indexed: 01/31/2023]
Abstract
When a heavy atomic nucleus splits (fission), the resulting fragments are observed to emerge spinning1; this phenomenon has been a mystery in nuclear physics for over 40 years2,3. The internal generation of typically six or seven units of angular momentum in each fragment is particularly puzzling for systems that start with zero, or almost zero, spin. There are currently no experimental observations that enable decisive discrimination between the many competing theories for the mechanism that generates the angular momentum4-12. Nevertheless, the consensus is that excitation of collective vibrational modes generates the intrinsic spin before the nucleus splits (pre-scission). Here we show that there is no significant correlation between the spins of the fragment partners, which leads us to conclude that angular momentum in fission is actually generated after the nucleus splits (post-scission). We present comprehensive data showing that the average spin is strongly mass-dependent, varying in saw-tooth distributions. We observe no notable dependence of fragment spin on the mass or charge of the partner nucleus, confirming the uncorrelated post-scission nature of the spin mechanism. To explain these observations, we propose that the collective motion of nucleons in the ruptured neck of the fissioning system generates two independent torques, analogous to the snapping of an elastic band. A parameterization based on occupation of angular momentum states according to statistical theory describes the full range of experimental data well. This insight into the role of spin in nuclear fission is not only important for the fundamental understanding and theoretical description of fission, but also has consequences for the γ-ray heating problem in nuclear reactors13,14, for the study of the structure of neutron-rich isotopes15,16, and for the synthesis and stability of super-heavy elements17,18.
Collapse
Affiliation(s)
- J N Wilson
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France.
| | - D Thisse
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - M Lebois
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - N Jovančević
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - D Gjestvang
- Department of Physics, University of Oslo, Blindern, Oslo, Norway
| | - R Canavan
- Department of Physics, University of Surrey, Guildford, UK.,National Physical Laboratory, Teddington, UK
| | - M Rudigier
- Department of Physics, University of Surrey, Guildford, UK.,Technische Universität Darmstadt, Fachbereich Physik, Institut für Kernphysik, Darmstadt, Germany
| | | | - R-B Gerst
- Institut für Kernphysik, Universität zu Köln, Cologne, Germany
| | | | - E Adamska
- Faculty of Physics, University of Warsaw, Warsaw, Poland
| | - P Adsley
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - A Algora
- IFIC, CSIC-University of Valencia, Valencia, Spain.,Institute for Nuclear Research (Atomki), Debrecen, Hungary
| | - M Babo
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - K Belvedere
- Department of Physics, University of Surrey, Guildford, UK
| | - J Benito
- Grupo de Fisica Nuclear & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
| | | | - A Blazhev
- Institut für Kernphysik, Universität zu Köln, Cologne, Germany
| | - A Boso
- National Physical Laboratory, Teddington, UK
| | - S Bottoni
- INFN, Milan, Italy.,Dipartimento di Fisica, Universitá degli Studi di Milano, Milan, Italy
| | - M Bunce
- National Physical Laboratory, Teddington, UK
| | - R Chakma
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | | | - S Courtin
- Université de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg, France
| | | | - P Davies
- School of Physics and Astronomy, University of Manchester, Manchester, UK
| | - C Delafosse
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - M Fallot
- Subatech, IMT-Atlantique, Université de Nantes, Nantes, France
| | - B Fornal
- Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Poland
| | - L Fraile
- Grupo de Fisica Nuclear & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
| | - A Gottardo
- INFN Laboratori Nazionali di Legnaro, Legnaro, Italy
| | - V Guadilla
- Subatech, IMT-Atlantique, Université de Nantes, Nantes, France
| | - G Häfner
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France.,Institut für Kernphysik, Universität zu Köln, Cologne, Germany
| | - K Hauschild
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - M Heine
- Université de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg, France
| | - C Henrich
- Technische Universität Darmstadt, Fachbereich Physik, Institut für Kernphysik, Darmstadt, Germany
| | - I Homm
- Technische Universität Darmstadt, Fachbereich Physik, Institut für Kernphysik, Darmstadt, Germany
| | - F Ibrahim
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - Ł W Iskra
- INFN, Milan, Italy.,Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Poland
| | - P Ivanov
- National Physical Laboratory, Teddington, UK
| | - S Jazrawi
- Department of Physics, University of Surrey, Guildford, UK.,National Physical Laboratory, Teddington, UK
| | - A Korgul
- Faculty of Physics, University of Warsaw, Warsaw, Poland
| | - P Koseoglou
- Technische Universität Darmstadt, Fachbereich Physik, Institut für Kernphysik, Darmstadt, Germany.,GSI Helmoltzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany
| | - T Kröll
- Technische Universität Darmstadt, Fachbereich Physik, Institut für Kernphysik, Darmstadt, Germany
| | | | - L Le Meur
- Subatech, IMT-Atlantique, Université de Nantes, Nantes, France
| | - S Leoni
- INFN, Milan, Italy.,Dipartimento di Fisica, Universitá degli Studi di Milano, Milan, Italy
| | - J Ljungvall
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - A Lopez-Martens
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - R Lozeva
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - I Matea
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - K Miernik
- Faculty of Physics, University of Warsaw, Warsaw, Poland
| | - J Nemer
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - S Oberstedt
- European Commission, Joint Research Centre, Geel, Belgium
| | - W Paulsen
- Department of Physics, University of Oslo, Blindern, Oslo, Norway
| | - M Piersa
- Faculty of Physics, University of Warsaw, Warsaw, Poland
| | - Y Popovitch
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - C Porzio
- INFN, Milan, Italy.,Dipartimento di Fisica, Universitá degli Studi di Milano, Milan, Italy.,TRIUMF, Vancouver, British Columbia, Canada
| | - L Qi
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - D Ralet
- Grand Accélérateur National d'Ions Lourds, Caen, France
| | - P H Regan
- Department of Physics, University of Surrey, Guildford, UK.,National Physical Laboratory, Teddington, UK
| | - K Rezynkina
- Institute for Nuclear and Radiation Physics, Katholieke Universiteit Leuven, Leuven, Belgium
| | - V Sánchez-Tembleque
- Grupo de Fisica Nuclear & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
| | - S Siem
- Department of Physics, University of Oslo, Blindern, Oslo, Norway
| | - C Schmitt
- Université de Strasbourg, CNRS, IPHC UMR 7178, Strasbourg, France
| | - P-A Söderström
- Technische Universität Darmstadt, Fachbereich Physik, Institut für Kernphysik, Darmstadt, Germany.,Extreme Light Infrastructure-Nuclear Physics, Horia Hulubei National Institute for Physics and Nuclear Engineering, Bucharest-Măgurele, Romania
| | - C Sürder
- Technische Universität Darmstadt, Fachbereich Physik, Institut für Kernphysik, Darmstadt, Germany
| | - G Tocabens
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - V Vedia
- Grupo de Fisica Nuclear & IPARCOS, Universidad Complutense de Madrid, CEI Moncloa, Madrid, Spain
| | - D Verney
- Université Paris-Saclay, CNRS/IN2P3, IJC Laboratory, Orsay, France
| | - N Warr
- Institut für Kernphysik, Universität zu Köln, Cologne, Germany
| | - B Wasilewska
- Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Poland
| | - J Wiederhold
- Technische Universität Darmstadt, Fachbereich Physik, Institut für Kernphysik, Darmstadt, Germany
| | - M Yavahchova
- Institute for Nuclear Research and Nuclear Energy, Bulgarian Academy of Sciences, Sofia, Bulgaria
| | - F Zeiser
- Department of Physics, University of Oslo, Blindern, Oslo, Norway
| | - S Ziliani
- INFN, Milan, Italy.,Dipartimento di Fisica, Universitá degli Studi di Milano, Milan, Italy
| |
Collapse
|
4
|
Abstract
Abstract
Recent progress in the production of heavy nuclei far from stability and in the studies of nuclear and chemical properties of heavy actinides is briefly reviewed. Exotic nuclear decay properties including nuclear fission of heavy nuclei, measurements of first ionization potentials of heavy actinides, and redox studies of heavy actinides are described. Brief history of discovery of the transuranium elements is also presented.
Collapse
Affiliation(s)
- Yuichiro Nagame
- Advanced Science Research Center, Japan Atomic Energy Agency (JAEA) , Tokai-mura, Ibaraki 319-1195 , Japan
- Graduate School of Science and Engineering , Ibaraki University , Mito, Ibaraki 310-8512 , Japan
| |
Collapse
|
5
|
Impact of pear-shaped fission fragments on mass-asymmetric fission in actinides. Nature 2018; 564:382-385. [PMID: 30568195 DOI: 10.1038/s41586-018-0780-0] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 10/31/2018] [Indexed: 11/08/2022]
Abstract
Nuclear fission of heavy (actinide) nuclei results predominantly in asymmetric mass splits1. Without quantum shell effects, which can give extra binding energy to their mass-asymmetric shapes, these nuclei would fission symmetrically. The strongest shell effects appear in spherical nuclei, such as the spherical 'doubly magic' (that is, both its atomic and neutron numbers are 'magic' numbers) nucleus 132Sn, which contains 50 protons and 82 neutrons. However, a systematic study of fission2 has shown that heavy fission fragments have atomic numbers distributed around Z = 52 to Z = 56, indicating that the strong shell effects in 132Sn are not the only factor affecting actinide fission. Reconciling the strong spherical shell effects at Z = 50 with the different Z values of fission fragments observed in nature has been a longstanding puzzle3. Here we show that the final mass asymmetry of the fragments is also determined by the extra stability provided by octupole (pear-shaped) deformations, which have been recently confirmed experimentally around 144Ba (Z = 56)4,5, one of very few nuclei with shell-stabilized octupole deformation6. Using a quantum many-body model of superfluid fission dynamics7, we find that heavy fission fragments are produced predominantly with 52 to 56 protons, which is associated with substantial octupole deformation acquired on the way to fission. These octupole shapes, which favour asymmetric fission, are induced by deformed shells at Z = 52 and Z = 56. By contrast, spherical magic nuclei are very resistant to octupole deformation, which hinders their production as fission fragments. These findings may explain surprising observations of asymmetric fission in nuclei lighter than lead8.
Collapse
|
6
|
Möller P. Essentials of the macroscopic-microscopic folded-Yukawa approach and examples of its record in providing nuclear-structure data for simulations. EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201818401013] [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
The macroscopic-microscopic model based on the folded-Yukawa singleparticle potential and a “finite-range” macroscopic model is probably the approach that has provided the most reliable predictions of a large number of nuclear-structure properties for all nuclei between the proton and neutron drip lines. I will describe some basic features of the model and the development philosophy that may be the reason for its success. Examples of quantities modeled within the same model framework are, nuclear masses, ground-state level structure, including spins, ground-state shapes, fission barriers, heavy-ion fusion barriers, sub-barrier fusion cross sections, β-decay half-lives and delayed neutron emission probabilities, shape coexistence, and α-decay Qα energies to name a few. I will show how well it predicted various properties measured after published results. Rather than giving an incomplete model description here I will give a timeline of model development and provide references to typical applications and references that are sufficiently complete that several individuals have written computer codes based on these references, codes whose results have excellent agreement with ours.
Collapse
|
7
|
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.
Collapse
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
| | | | | |
Collapse
|
8
|
Nishio K, Hirose K, Vermeulen M, Makii H, Orlandi R, Tsukada K, Asai M, Toyoshima A, Sato TK, Nagame Y, Chiba S, Aritomo Y, Tanaka S, Ohtsuki T, Tsekhanovich I, Petrache CM, Andreyev A. Study of fission using multi-nucleon transfer reactions. EPJ WEB OF CONFERENCES 2018. [DOI: 10.1051/epjconf/201816900013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Multi-nucleon transfer channels of the reactions of 18O+232Th, 18O+238U, 18O+248Cm were used to measure fission-fragment mass distribution for various nuclides and their excitation energy dependence. Predominantly asymmetric fission is observed at low excitation energies for all the studied cases, with an increase of the symmetric fission towards high excitation energies. Experimental data are compared with predictions of the fluctuation-dissipation model, where effects of multi-chance fission (neutron evaporation prior to fission) was introduced. It was shown that a reliable understanding of the observed fission fragment mass distributions can be obtained only invoking multi-chance fissions.
Collapse
|
9
|
Huang W, Audi G. Corrections of alpha- and proton-decay energies in implantation experiments. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201714610007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
10
|
Nishio K, Hirose K, Léguillon R, Makii H, Orlandi R, Tsukada K, Smallcombe J, Chiba S, Aritomo Y, Tanaka S, Ohtsuki T, Tsekhanovich I, Petrache CM, Andreyev A. Experimental fission study using multi-nucleon transfer reactions. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201714604009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
11
|
Nishio K, Hirose K, Mark V, Makii H, Orlandi R, Tsukada K, Asai M, Toyoshima A, Sato TK, Nagame Y, Chiba S, Aritomo Y, Tanaka S, Ohtsuki T, Tsekhanovich I, Petrache CM, Andreyev A. Study of fission using multi-nucleon transfer reactions. EPJ WEB OF CONFERENCES 2017. [DOI: 10.1051/epjconf/201716300041] [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
|
12
|
|
13
|
Benlliure J. Dynamical effects in fission investigated at high excitation energy. EPJ WEB OF CONFERENCES 2016. [DOI: 10.1051/epjconf/201611708001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
14
|
Nagame Y, Nakahara H. Two-mode fission – experimental verification and characterization of two fission-modes. RADIOCHIM ACTA 2014. [DOI: 10.1524/ract.2012.1968] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Abstract
Experimental verification and characterization of the two-mode fission are reviewed. The presence of two independent deformation-paths in low energy fission of actinides is demonstrated by studying correlation among saddle-point configurations, scission-point configurations, and mass-yield distributions; the elongated scission configuration is related with the fission process that goes over a higher threshold energy and results in a symmetric mass-division mode, while the compact scission configuration with the process that experiences a lower threshold ends up with an asymmetric mass-division mode. Based on an extensive systematic analysis of scission properties in a wide range of actinide fission, the bimodal fission observed in the spontaneous fission of the heavy actinides is interpreted as the result of the presence of two fission paths, namely, the ordinary asymmetric fission path and a strongly shell-influenced symmetric mode.
Collapse
Affiliation(s)
- Y. Nagame
- Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195, Japan
| | - H. Nakahara
- Department of Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan
| |
Collapse
|
15
|
Panebianco S, Dubray N, Goriely S, Hilaire S, Lemaître JF, Sida JL. SPY: a new scission-point model based on microscopic inputs to predict fission fragment properties. EPJ WEB OF CONFERENCES 2014. [DOI: 10.1051/epjconf/20136900016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
16
|
Measurement of the first ionization potential of astatine by laser ionization spectroscopy. Nat Commun 2013; 4:1835. [PMID: 23673620 PMCID: PMC3674244 DOI: 10.1038/ncomms2819] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Accepted: 03/27/2013] [Indexed: 01/07/2023] Open
Abstract
The radioactive element astatine exists only in trace amounts in nature. Its properties can therefore only be explored by study of the minute quantities of artificially produced isotopes or by performing theoretical calculations. One of the most important properties influencing the chemical behaviour is the energy required to remove one electron from the valence shell, referred to as the ionization potential. Here we use laser spectroscopy to probe the optical spectrum of astatine near the ionization threshold. The observed series of Rydberg states enabled the first determination of the ionization potential of the astatine atom, 9.31751(8) eV. New ab initio calculations are performed to support the experimental result. The measured value serves as a benchmark for quantum chemistry calculations of the properties of astatine as well as for the theoretical prediction of the ionization potential of superheavy element 117, the heaviest homologue of astatine.
Collapse
|
17
|
Lynch K, Billowes J, Bissell M, Budincevic I, Cocolios T, De Groote R, De Schepper S, Fedosseev V, Flanagan K, Franchoo S, Garcia Ruiz R, Heylen H, Marsh B, Mason P, Neyens G, Procter T, Rossel R, Rothe S, Simpson G, Smith A, Strashnov I, Stroke H, Walker P, Wendt K, Wood R. CRIS: A new method in isomeric beam production. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20136301007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
18
|
Andreev A, Adamian G, Antonenko N. Influence of shell effects on mass asymmetry in fission of different Hg isotopes. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20136206007] [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
|
19
|
|
20
|
Ramachandran K, Hinde D, Dasgupta M, Williams E, Wakhle A, Luong D, Evers M, Carter I, Das S. Fission fragment mass distribution in the 13C+ 182W and 176Yb reactions. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20136302017] [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
|
21
|
Kondev F, Carpenter M, Zhu S, Janssens R, Ahmad I, Back B, Bertone P, Chen J, Chiara C, Copos C, Greene J, Hoffman C, Kay B, Khoo T, Lauritsen T, McCutchan E, Nair C, Rogers A, Seweryniak D, Hartley DJ. Spectroscopy of Neutron-Deficient Nuclei Near the Z=82 Closed Shell via Symmetric Fusion Reactions. EPJ WEB OF CONFERENCES 2013. [DOI: 10.1051/epjconf/20136301013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
22
|
Castro-Chavez F. The Rules of Variation Expanded, Implications for the Research on Compatible Genomics. BIOSEMIOTICS 2011; 2011:1-25. [PMID: 21743816 PMCID: PMC3130522 DOI: 10.1007/s12304-011-9118-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The main focus of this article is to present the practical aspect of the code rules of variation and the search for a second set of genomic rules, including comparison of sequences to understand how to preserve compatible organisms in danger of extinction and how to generate biodiversity. Three new rules of variation are introduced: 1) homologous recombination, 2) a healthy fertile offspring, and 3) comparison of compatible genomes. The novel search in the natural world for fully compatible genomes capable of homologous recombination is explored by using examples of human polymorphisms in the LDLRAP1 gene, and by the production of fertile offspring by crossbreeding. Examples of dogs, llamas and finches will be presented by a rational control of: natural crossbreeding of organisms with compatible genomes (something already happening in nature), the current work focuses on the generation of new varieties after a careful plan. This study is presented within the context of biosemiotics, which studies the processing of information, signaling and signs by living systems. I define a group of organisms having compatible genomes as a single theme: the genomic species or population, able to speak the same molecular language through different accents, with each variety within a theme being a different version of the same book. These studies have a molecular, compatible genetics context. Population and ecosystem biosemiotics will be exemplified by a possible genetic damage capable of causing mutations by breaking the rules of variation through the coordinated patterns of atoms present in the 9/11 World Trade Center contaminated dust (U, Ba, La, Ce, Sr, Rb, K, Mn, Mg, etc.), combination that may be able to overload the molecular quality control mechanisms of the human body. I introduce here the balance of codons in the circular genetic code: 2[1(1)+1(3)+1(4)+4(2)]=2[2(2)+3(4)].
Collapse
|