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**SYNTHESIS OF SUPER HEAVY ELEMENTS**

K.Subotic INN VINCA

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New elements

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**MM Shell stabilization**

LD fission barrier up to Z=106 Shell effects for Z>106 Nshell=162 Zshell=108 experimentally confirmed Nshell~184 Zshell=114

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**Production Methods Z>100 needs : accelerator technology**

Atom per atom identification according to of the characteristics nuclear decay cross sections depend on Z1Z2 at formation and Ex at survival Cold fusion provides lower excitation due to the shell effects of Pb target but higher Coulomb repulsion. Produced n-deficient SHE, long known chains and ending nuclei Hot fusion provides lower Coulomb barrier, but higher excitation. Produced n-sufficient nuclei, short unknown chains, fissile ending nuclei

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**Island of Super Heavy Elements**

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**Cold Fusion: Signature of 112 (Darmstadt )**

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**Hot fusion: Signature of 114 (Dubna )**

Confirmation by observing the decay pattern of 114 made in Ca+Pu , in decay of 116 made in Ca+Cm

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**Odd Z nuclei decay chains in Dubna experiments**

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**QT systematic compared to calculation**

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Z=118 predictions MM (Zshell=114) , HFB (Zshell=124, 126) , and RMF (Zshell=120) model calculations point at the existence of the closed spherical shell at N=184 (or 182); however, they are at variance in predicting the proton shell. These disagreements will show out in predicting the decay properties of elements with Z118. The uncertainty of energy more than 1 MeV, Т varies by more than two orders of magnitude. The differences in fission barrier predictions influence the survivability of CN, thus also the cross sections MM model expected formation cross sections of the nuclei with Z=118 are rather lower than those of the isotopes of proton shell element 114 Moving towards the proton shell 124 or 126 according to other models, on the contrary, results in higher cross sections of xn-evaporation channels.

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**Viola-Seaborg T&Q for even Z**

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**Can we produce SHE using RNB?**

Reduction of RNB intensities should be compensated by increased cross section In halo nuclei induced fusion 6He+ 238U enhancement of fusion cross section not found. Sub barrier contributions are coming from transfer and break-up. 124,132Sn + 64Ni , sub-barrier cross section increased for n rich double magic projectile

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**Possible stable beams: Inverse fission consideration (Oganessian EPJ2002)**

Fusion of the most probable cold 222Th fission fragment pair 86Kr+136Xe provides 3 orders of magnitude higher cross section at Ex~20 than other partners.. 130Xe instead of 136Xe causes a decrease in σ for fusion-fission by almost 3 orders of magnitude. Means that collective nuclear motion from the contact configuration of 86Kr and 136Xe (both stable isotopes) to the saddle point of 222Th follows a shorter path compared to the case of 216Th( 130Xe+86Kr), which undergoes mainly symmetric fission.

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**Promising reaction systems**

Inverse fission: nuclei close in charge and mass to the most probable cold fission fragments of the SHE may have enhanced fusion caused by shell structure properties Heavy projectiles: higher Coulomb barrier but lower excitation, i.e. higher survival probability 76Se +238U (SPIRAL) 64Ni + 248Cm312124(DUBNA) RNB: 132Sn close to the shells Z=50 and N = 82 160Gd(132Sn,n)291114 at1pµA and cross-section of order of 10 pb

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**Dubna GFRS separation and detector system:**

H gas fill, TOF analysis, veto detector, beam off time measurements Software analysis

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**Identification of mass and charge**

Possible ID improvements by using :ion traps, mass spectrometers , time-of-flight measurements, high-resolution calorimeters, laser spectroscopy , chemical techniques of identification.

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**Berkeley, GSI, Dubna, Riken, Ganil, Jyvaskyla, EURISOL… Challenges**

Beams/Targets? Cold fusion? Hot fusion? Inverse fission? RNB: Cross section? Microscopic details Spectroscopy SHE identification Magic numbers? Masses? Half-lives? Fusion dynamics Fission barrier Fission path Shell effects Deformation effects

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