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SYNTHESIS OF SUPER HEAVY ELEMENTS K.Subotic INN VINCA.

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Presentation on theme: "SYNTHESIS OF SUPER HEAVY ELEMENTS K.Subotic INN VINCA."— Presentation transcript:

1 SYNTHESIS OF SUPER HEAVY ELEMENTS K.Subotic INN VINCA

2 New elements

3 MM Shell stabilization LD fission barrier up to Z=106 Shell effects for Z>106 N shell =162 Z shell =108 experimentally confirmed N shell ~184 Z shell =114

4 Production Methods Z>100 needs : accelerator technology Z>100 needs : accelerator technology Atom per atom identification according to of the characteristics nuclear decay Atom per atom identification according to of the characteristics nuclear decay cross sections depend on Z 1 Z 2 at formation and E x at survival cross sections depend on Z 1 Z 2 at formation and E x 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 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 Hot fusion provides lower Coulomb barrier, but higher excitation. Produced n-sufficient nuclei, short unknown chains, fissile ending nuclei

5 Island of Super Heavy Elements

6 Cold Fusion: Signature of 112 (Darmstadt )

7 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

8 Odd Z nuclei decay chains in Dubna experiments

9 QT systematic compared to calculation

10 Z=118 predictions MM (Z shell =114), HFB (Z shell =124, 126), and RMF (Z shell =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. MM (Z shell =114), HFB (Z shell =124, 126), and RMF (Z shell =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 Z  118. These disagreements will show out in predicting the decay properties of elements with Z  118. The uncertainty of energy more than 1 MeV, Т  varies by more than two orders of magnitude. 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.

11 Viola-Seaborg T&Q for even Z

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

13 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.

14 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 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 Heavy projectiles: higher Coulomb barrier but lower excitation, i.e. higher survival probability 76 Se + 238 U  314 126 (SPIRAL) 76 Se + 238 U  314 126 (SPIRAL) 64 Ni + 248 Cm  312 124(DUBNA) 64 Ni + 248 Cm  312 124(DUBNA) RNB: 132Sn close to the shells Z=50 and N = 82 160 Gd( 132 Sn,n) 291 114 at1pµA and cross-section of order of 10 pb

15 Dubna GFRS separation and detector system: H gas fill, TOF analysis, veto detector, beam off time measurements Software analysis

16 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.

17 Berkeley, GSI, Dubna, Riken, Ganil, Jyvaskyla, EURISOL… Challenges Beams/Targets? Beams/Targets? Cold fusion? Cold fusion? Hot fusion? Hot fusion? Inverse fission? Inverse fission? RNB: Cross section? RNB: Cross section? Microscopic details Microscopic details Spectroscopy Spectroscopy SHE identification SHE identification Magic numbers? Masses? Half-lives? Fusion dynamics Fission barrier Fission path Shell effects Deformation effects


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