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The pecul i arit ies of the production and decay of superheavy nuclei

99 –th Session of the JINR Scintific Council 19 - 20 January 2006. The pecul i arit ies of the production and decay of superheavy nuclei. M.G.Itkis. Flerov Laboratory of Nuclear Reactions, JINR, Dubna, Russia. The dynamics of the fusion-fission of superheavy nuclei

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The pecul i arit ies of the production and decay of superheavy nuclei

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  1. 99 –th Session of the JINR Scintific Council 19 - 20 January 2006 The peculiarities of the production and decay of superheavy nuclei M.G.Itkis Flerov Laboratory of Nuclear Reactions, JINR, Dubna, Russia

  2. The dynamics of the fusion-fission of superheavy nuclei • Experimental results. The peculiarities of the observables,the signatures of the Fusion-Fission/Quasi-Fission processes, multimodal fission phenomena • The recent results on synthesis of superheavy nuclei • The perspectives of the “hot” fusion reaction for the production of superheavy nuclei

  3. Shape evolution in Fusion-Fission reactions • Elastic scattering • Coulomb excitation • Quasi-elastic scattering • Deep-inelastic scattering • Incomplete pulse transfer • Fast-fission • Quasi-fission • Fusion → CN → Fission • Fusion → CN → de-excitation (n,)→ ER In dependence on impact parameter and projectile energy :

  4. Kinematics coincidence method. Double arm time-of-flight spectrometer CORSET

  5. E* 33 MeV Experimental results • The sharp change of the MED triangular shape for the reaction 48Ca+208Pb, where Fusion-Fission process dominates, to the Quasi-Fission shape of MED for the 286112-296116 nuclei. • The wide two-humped mass distribution with high peak of heavy fragment near double magic lead (MH208) for the Quasi-Fission process. • In spite of the dominating role of the Quasi-Fission process for these reactions we assume that in the symmetric region of the fragment masses (A/220) FF process coexists with QF. • The Fusion-Fission mass distribution is asymmetric in shape with mass of the light fragment ML132-134 amu( see on the framings) Mass-energy distributions of the fission fragments of 256102- 296116 nuclei produced in “hot” fusion reactions with 48Ca-projectiles

  6. Mass Asymmetry in Low Energy Fission of Superheavy nuclei E*33-40 MeV

  7. Total kinetic energy (MeV) Mass asymmetry (A1-A2)/(A1+A2) Yield,% Fragment mass number (u) 48Ca + 248Cm 296116 Hot fusion reaction Fusion-Fission Dynamics M.G.Itkis, Yu.Ts.Oganessian, V.I.Zagrebaev, Phys.Rev.C65,2002, 044602

  8. Cold fusion reaction

  9. Neutron and -emission as probe FF/QF Two-dimensional matrixes TKE-Mass, Mass Yields, neutron multiplicities (pre, post and tot) for the reactions 48Ca+208Pb and 48Ca+238U Neutron multi-detectors “DEMON” with trigger of fission fragments “CORSET”

  10. Total neutron multiplicities as function of atomic number of compound nuclei produced in the reaction with 26Mg, 48Ca and 58Fe-projectiles Two-dimensional matrixes TKE-Mass, Mass Yields, neutron and -multiplicitiesfor the reaction with 48Ca-projectiles on the targets 208Pb,238U, 244Pu,248Cm

  11. Capture and Fusion-Fission Cross Sections The perspectives of the “hot” fusion reaction for the production of superheavy nuclei

  12. Shell effects manifestation QF/cap (%)

  13. x 400 → Ca5+ technology of the target preparation – 0.3 mg/cm2 Separation of super heavy nuclei and detection of their radioactive decays now: DGFRS isotope enrichment 98-99% S-2 separator (Sarov) isotope production high flux reactors (Oak Ridge, Dimitrovgrad) Natural occurrence of Ca isotopes (in %): 40Ca – 96.94 42Ca – 0.647 43Ca – 0.135 44Ca – 2.086 46Ca – 0.004 48Ca – 0.187

  14. v (A=48) = 0.11 c q = 16.5+ v (A=288) = 0.017 c q = 6.2+

  15. Isotope charge (Z) and mass (A) identifications obtained by the measurements of neutron evaporation cross sections vs. excitation energy of compound nucleus

  16. Decay Chains Observed in 243Am + 48Ca Reaction

  17. odd-odd a

  18. 2002 - 2004 290 29 1 245Cm+48Ca 116 116 a a 1 1 10.74 MeV 10.5 MeV 8 242Pu+48Ca 28 6 28 7 114 114 26.3 ms 6.23 ms a a 2 2 238U+48Ca 10.02 MeV 282 283 10.16 MeV SF(~60%) 112 112 0.68 s a 0.55 s 3 9.5 MeV 2 79 SF 11 0 a 7.87 s 1.0 ms 4 2 75 970 . MeV SF(~90%) 1 08 a 0.28 s 5 2 71 9.30 MeV a 1 06 6 0.3 s 2 67 SF(~30%) 8.53 MeV 1 04 2.80 min SF 1.84 h Synthesis of Element 118 in 249Cf + 48Ca Reaction 2002 2005

  19. Number of observed decays Z = 118 3 116 23 114 45 112 52

  20. The formation of 294116 in the reactions with 48Ca and 50Ti-ions Mass-energy distributions of the fission fragments

  21. Capture cross sections for the reactions 50Ti+244Puand 48Ca+246Cm

  22. Reactions of the production of 116-122 elements with 58Fe and 64Ni-projectiles N=174 N=182 N=184 N=184

  23. the search for SHE in Cosmic rays 108 y 105 y 1y 1d

  24. Search in Nature Chemical properties(relativistic effect) Astrophysics(search for SHE in cosmic rays) Nucleosynthesis (test of the r-s process) Atomic physics(structure of SH-atoms) Elements with Z ≥ 120

  25. Flerov Laboratory of Nuclear Reactions of JINR …in February Thanks for your attention

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