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Title: Experiments on the synthesis of superheavy nuclei Fl 284 and Fl 285 in the Pu 239 , 240 + Ca 48 reactions

Journal Article · · Physical Review C, Nuclear Physics
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  1. Joint Institute for Nuclear Research, Dubna (Russian Federation). Flerov Laboratory of Nuclear Reactions
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Physics Division
  3. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Physics Division; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Physics Division; Univ. of Warsaw (Poland). Faculty of Physics
  5. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Science and Technology Partnerships Directorate
  6. Vanderbilt Univ., Nashville, TN (United States). Department of Physics and Astronomy
  7. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States). Nuclear and Chemical Sciences Division
  8. Univ. of Notre Dame, IN (United States). Department of Physics

In this study, irradiations of 239Pu and 240Pu targets with 48Ca beams aimed at the synthesis of Z = 114 flerovium isotopes were performed at the Dubna Gas Filled Recoil Separator. A new spontaneously fissioning (SF) isotope 284Fl was produced for the first time in the 240Pu + 48Ca (250 MeV) and 239Pu + 48Ca (245 MeV) reactions. The cross section of the 239Pu (48Ca , 3 n) 284Fl reaction channel was about 20 times lower than predicted by theoretical models and about 50 times lower than the maximum fusion-evaporation cross section for the 3 n and 4 n channels measured in the 244Pu + 48Ca reaction. In the 240Pu + 48Ca experiment, performed at 245 MeV in order to maximize the 3 n -evaporation channel, three decay chains of 285Fl were detected. The α -decay energy of 285Fl was measured for the first time and decay properties of its descendants 281Cn , 277Ds , 273Hs , 269Sg, and 265Rf were determined with higher accuracy. The assignment of SF events observed during the irradiation of the 240Pu target with a 250 MeV 48Ca beam to 284Fl decay is presented and discussed. The cross sections at both 48Ca energies are similar and exceed that observed in the reaction with the lighter isotope 239Pu by a factor of 10. Lastly, the decay properties of the synthesized nuclei and their production cross sections indicate a rapid decrease of stability of superheavy nuclei as the neutron number decreases from the predicted magic neutron number N = 184 .

Research Organization:
Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Nuclear Physics (NP)
DOE Contract Number:
AC05-00OR22725; AC52-07NA27344; FG05-88ER40407
OSTI ID:
1339373
Journal Information:
Physical Review C, Nuclear Physics, Vol. 92, Issue 3; ISSN 0556-2813
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English

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48 Ca induced reactions for the synthesis of isotopes 284–292 Fl journal November 2017
The predictive accuracy of analytical formulas and semiclassical approaches for α decay half-lives of superheavy nuclei journal January 2018
Nuclear fission: a review of experimental advances and phenomenology journal November 2017
Superheavy nuclei: from predictions to discovery journal January 2017
Correlations between neutrons and protons near the Fermi surface and Q α of superheavy nuclei journal January 2016
Systematic study of probable projectile-target combinations for the synthesis of the superheavy nucleus 120 302 journal August 2016
Possibilities of production of transfermium nuclei in charged-particle evaporation channels journal October 2016
Synthesis of 119 292 303 superheavy elements using Ca- and Ti-induced reactions journal September 2017
Neutron-deficient superheavy nuclei obtained in the Pu 240 + Ca 48 reaction journal January 2018
Effect of shell corrections on the α -decay properties of Fl 280 305 isotopes journal September 2018
A Detail Investigation on the Synthesis of Superheavy Element Z = 119 journal November 2019
Remarks on the fission barriers of super-heavy nuclei journal April 2016
Review of even element super-heavy nuclei and search for element 120 journal June 2016
Spontaneous fission properties of superheavy elements journal April 2017
Theoretical predictions for $\alpha$-decay properties of 283-339Og using a shell-effect induced generalized liquid-drop model journal September 2019
2015 Update of the discoveries of nuclides journal June 2016