1. 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. Experimental results The sharp change of the MED triangular shape for the reaction 48 Ca+ 208 Pb, where Fusion-Fission process dominates, to the Quasi-Fission shape of MED for the 286 112- 296 116 nuclei. The wide two-humped mass distribution with high peak of heavy fragment near double magic lead (M H  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 M L  132-134 amu ( see on the framings) Mass-energy distributions of the fission fragments of 256 102- 296 116 nuclei produced in “hot” fusion reactions with 48 Ca-projectiles E*  33 MeV

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

8. Hot fusion reaction 48 Ca + 248 Cm  296 116 Fusion-Fission Dynamics M.G.Itkis, Yu.Ts.Oganessian, V.I.Zagrebaev, Phys.Rev.C65,2002, 044602 Total kinetic energy (MeV) Mass asymmetry (A 1 -A 2 )/(A 1 +A 2 ) Fragment mass number (u) Yield,%

9. Cold fusion reaction

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

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

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

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

14. . Fusion probability

15. σ xn = P xn ∙ Π (Γ n / Γ f ) I ~ (Γ n / Γ f ) x (Γ n / Γ f ) I ~ exp [(B f – B n ) / T] i=1 i=x where B f = B f LD + ΔE Shell 0 Survival probability the limit of the exp. sensitivity

16. Natural occurrence of Ca isotopes (in %): 40 Ca – 96.94 42 Ca – 0.647 43 Ca – 0.135 44 Ca – 2.086 46 Ca – 0.004 48 Ca – 0.187 x 400 → Ca 5+ isotope production high flux reactors (Oak Ridge, Dimitrovgrad ) isotope enrichment 98-99% S-2 separator (Sarov) technology of the target preparation – 0.3 mg/cm 2 Separation of super heavy nuclei and detection of their radioactive decays now: DGFRS

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

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

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

20. odd-odd 

21. Synthesis of Element 118 in 249 Cf + 48 Ca Reaction 2002 2005 2002 - 2004 245 Cm+ 48 Ca 242 Pu+ 48 Ca 238 U+ 48 Ca 10.02 MeV 26.3 ms 0.68 s 116 114 112 291 287 283 1  2  SF(~90%) SF(~30%) 10.74 MeV 970. MeV 7.87 s 0.28 s 110 108 279 275 3  4  9.5 MeV 8.53 MeV 0.3 s 2.80 min 104 267 5  6  9.30 MeV 1.84 h SF 10.16 MeV 6.23 ms 0.55 s 116 112 290 282 1  2  1.0 ms SF SF(~60%) 10.5 MeV8 114 286 106 271

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

26. The formation of 294 116 in the reactions with 48 Ca and 50 Ti-ions Mass-energy distributions of the fission fragments

27. Capture cross sections for the reactions 50 Ti+ 244 Pu and 48 Ca+ 246 Cm

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

29. 10 8 y 10 5 y 1 y1 y 1 d1 d the search for SHE in Cosmic rays

30. 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

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