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Z>92 (Heaviest Element in Nature) and upto Z=100-101

Search for Superheavy element and Role of Fission Dynamics. Z>92 (Heaviest Element in Nature) and upto Z=100-101 achieved by n irradiation or p, a, and d bombardment in Cyclotron (1940-1955) (LBL) Z=102-106 by Light or Heavy-ion induced Fusion

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Z>92 (Heaviest Element in Nature) and upto Z=100-101

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  1. Search for Superheavy element and Role of Fission Dynamics • Z>92 (Heaviest Element in Nature) and upto Z=100-101 achieved by n irradiation or p, a, and d bombardment in Cyclotron (1940-1955) (LBL) • Z=102-106 by Light or Heavy-ion induced Fusion -evaporation using heavy element targets (1958-1974) Z=107-112 Heavy ion inuced fusion 208Pb,209Bi targets (GSI) Identified by recoil separation technique and connecting to known daughter decay after implanting into Si strip detectors. • Z=112-116 48Ca+Pu,Am,Cm,Cf (JINR, Dubna) Identified by gas filled separators and Si strip setectors SERC Course

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  6. Cross-section data and extrapolated values for cold-fusion Reactions (1n -evaporation channel) Cross-section increases with increasing isospin SERC Course

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  8. E*~33 MeV E*~34-38 MeV 48Ca+244Pu->289114+3n 48Ca+244Pu->288114+4n 48Ca+242Pu->287114+3n SERC Course

  9. Yury Ts. OganessianPure Appl. Chem., Vol. 76, No. 9, pp. 1715–1734, 2004. SERC Course

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  11. 48Ca+244Pu SERC Course

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  13. The flight time of the reaction products through SHIP is 2 ms. SERC Course

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  16. ∙ Cold Fusion 208Pb and 209Bi targets bombarded by the following projectiles: 48Ca, 50Ti, 54Cr,58Fe, 62Ni, 64Ni, 70Zn, 76Ge, 82Se, and 86Kr. ∎ Hot Fusion 48Ca projectiles bombarded targets of 238U, 244Pu, 243Am, 245Cm, 248Cm, and 249Cf, SERC Course

  17. BLDf gradually disappears Spherical Deformed SERC Course

  18. Fission barrier calculations of Smolanzuk et al. 106Sg has highest barrier with half life of 3 hrs SERC Course

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  20. For Z1Z2>1000 to 1650 depending on the value of the charge asymmetry, Zp/ZT. Extra push energies Swiatecki SERC Course

  21. No hindrance Onset of fusion limitation Due to Extra push energies Effective fissility : weighted mean of mono-nuclear and binary With weight for binary taken as 1/3 SERC Course

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  23. Injection direction Difference in energy Between touching Point and saddle point Small due to shell structure Of Ca and Pb Fusion area inside Saddle point All trajectories reaches fusion SERC Course

  24. Quasi-fission is dominant Extra pocket in mass Symmetric region Deep Quasi- fission SERC Course

  25. Evgeni A. Cherepanov Brazilian Journal of Physics, vol. 34, no. 3A, September, 2004 The curve V (Z,L = 0) (for the value of R corresponding to the pocket) has a few local minima, which reflect the shell structure in the interacting nuclei. SERC Course

  26. Mass asymm fluctuates around 0.5 and then relaxes quickly and Trajectory move to main pocket 48Ca+208Pb EX=50 MeV Aritomo and Ohta Pre-print Nuclear Physics A 744 (2004) 3–14 SERC Course

  27. Critical stage For FF mass Asymmetries large Turning stage For QF neck develops and speeds up fission keeping mass asymm. For deep QF mass asymm Relaxed in sub-pocket At TS 48Ca+244Pu Ex=50 MeV SERC Course

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  29. The smaller formation probability due to inhibition of fusion by competing mechanism:DIC,QF,FF,PEFAsymmetric channels: higher E* and unfavourable for survival SERC Course

  30. Transition from FF to QF Mass distribution for FF is asymmetric in shape With peak around 132 QF SERC Course

  31. Measurements at LNL,Legnaro (Italy) 470-630 MeV 80Se + 208Pb 372 MeV 56Fe+232Th 288116 470-630 MeV 312124 80Se + 232Th Measurement of fragment mass and kinetic energy and neutron correlations SERC Course

  32. Schematics of the setup for Se+Pb,Th experiment SERC Course

  33. 80Se+208Pb 470 MeV 80Se+232Th 470 MeV DIC dominates but significant events around symmetry SERC Course

  34. Se+Pb more asymmetric compared to Se+Th QF is expected to be more for Se+Th 80Se+208Pb 470 MeV 80Se+232Th 470 MeV SERC Course

  35. higher extra-push energy in the case of 80Se+232Th SERC Course

  36. 80Se+208Pb 288116 80Se+232Th 312124 ν sftot=10±2 for Se+Pb 12±1 for Fe+Th =17±2 for Se+Th SERC Course

  37. on average of about 0.6 neutron per unit Z SERC Course

  38. an increase of about 0.54 neutron per unit Z excitation energy gained by the system in its transition from the saddle to the scission point (the term ΔEx by Hilscher) that is known to show a strong mass and Z dependence. SERC Course

  39. JINR,Dubna SERC Course

  40. 41 detectors of DEMON at Dubna T. Materna et al. Nuclear Physics A734 (2004) 184-l 87 208±20 QF FF A/2±30 The pre-scission neutron multiplicity distribution simulated using backtracing procedure show two components for Ca+Pu Whereas for Ca+Pb only one component is seen SERC Course

  41. ?? Self-consistent Connectecd with known species SERC Course

  42. Change from Hot fusion to Cold fusion For higher N-Z SERC Course

  43. Survival probability Depends on fissiondelay And speed of cooling Mainly by neutron evaporation SERC Course

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  46. Expected intensities s-1for neutron-rich radioactive beams SPIRAL 24Ne 7 x 107 HI based 44Ar 5 x107 PIAFE 78Zn 108 84Ge 2 x108 94Kr 2 x 109 Reactor based Region beyond Z= 114 needs beam intensities in excess of 1014 s-1. With MAFF and spallation facility with 100μA proton of 1GeV Intensities may go up by 3 to 4 orders of magnitude SERC Course

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