SYNTHESIS OF SUPER HEAVY ELEMENTS

K.SuboticK.Subotic

INN VINCAINN VINCA

New elements

MM Shell stabilization

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

Production Methods

Z>100 needs : accelerator technologyZ>100 needs : accelerator technology Atom per atom identification according Atom per atom identification according

to of the characteristics nuclear decay to of the characteristics nuclear decay cross sections depend on Zcross sections depend on Z11ZZ22 at at

formation and Eformation and Exx at survival at survival

Cold fusion provides lower excitation Cold fusion provides lower excitation due to the shell effects of Pb target but due to the shell effects of Pb target but higher Coulomb repulsion. Produced n-higher Coulomb repulsion. Produced n-deficient SHE, long known chains and deficient SHE, long known chains and ending nucleiending nuclei

Hot fusion provides lower Coulomb Hot fusion provides lower Coulomb barrier, but higher excitation. Produced barrier, but higher excitation. Produced n-sufficient nuclei, short unknown n-sufficient nuclei, short unknown chains, fissile ending nucleichains, fissile ending nuclei

Island of Super Heavy Elements

Cold Fusion: Signature of 112 (Darmstadt )

Hot fusion: Signature of 114 (Dubna )

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

Odd Z nuclei decay chains in Dubna experiments

QT systematic compared to calculation

Z=118 predictions MM (MM (ZZshellshell=114) =114) , HFB , HFB

((ZZshellshell=124, 126) =124, 126) , and RMF , and RMF ((ZZshellshell=120)=120) model calculations model calculations point at the existence of the point at the existence of the closed spherical shell at closed spherical shell at NN=184 =184 (or 182); however, they are at (or 182); however, they are at variance in predicting the variance in predicting the proton shell.proton shell.

These disagreements will show These disagreements will show out in predicting the decay out in predicting the decay properties of elements with properties of elements with ZZ118. 118.

The uncertainty of energy more The uncertainty of energy more than 1 MeV, than 1 MeV, ТТ varies by more varies by more than two orders of magnitude.than two orders of magnitude.

The differences in fission The differences in fission barrier predictions influence the barrier predictions influence the survivability of CN, thus also survivability of CN, thus also the cross sectionsthe cross sections

MM model expected formation MM model expected formation cross sections of the nuclei with cross sections of the nuclei with ZZ=118 are rather lower than =118 are rather lower than those of the isotopes of proton those of the isotopes of proton shell element 114shell element 114

Moving towards the proton Moving towards the proton shell 124 or 126 according to shell 124 or 126 according to other models, on the contrary, other models, on the contrary, results in higher cross sections results in higher cross sections of of xnxn-evaporation channels.-evaporation channels.

Viola-Seaborg T&Q for even Z

Can we produce SHE using RNB?

Reduction of RNB Reduction of RNB intensities should be intensities should be compensated by increased compensated by increased cross sectioncross section

In halo nuclei induced fusionIn halo nuclei induced fusion 66He+He+ 238 238U enhancement of U enhancement of

fusion cross section not fusion cross section not found. Sub barrier found. Sub barrier contributions are coming contributions are coming from transfer and break-up. from transfer and break-up.

124,132124,132Sn + Sn + 6464Ni , sub-barrier cross Ni , sub-barrier cross section increased for n rich section increased for n rich double magic projectiledouble magic projectile

Possible stable beams: Inverse fission consideration

(Oganessian EPJ2002)

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

Promising reaction systems

Inverse fissionInverse fission: nuclei close in : nuclei close in charge and mass to the most charge and mass to the most probable cold fission fragments probable cold fission fragments of the SHE may have enhanced of the SHE may have enhanced fusion caused by shell structure fusion caused by shell structure propertiesproperties

Heavy projectilesHeavy projectiles: higher : higher Coulomb barrier but lower Coulomb barrier but lower excitation, i.e. higher survival excitation, i.e. higher survival probabilityprobability

7676Se +Se +238238UU314314126 (SPIRAL)126 (SPIRAL) 6464Ni + Ni + 248248CmCm312312124(DUBNA)124(DUBNA)

RNBRNB: 132Sn close to the shells: 132Sn close to the shellsZ=50 and Z=50 and N N = 82= 82 160160Gd(Gd(132132Sn,n)Sn,n)291291114114at1pat1pµA andµA and cross-section of order cross-section of order

of 10 pb of 10 pb

Dubna GFRS separation and detector system:

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

Identification of mass and charge

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

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 detailsMicroscopic details SpectroscopySpectroscopy SHE identificationSHE identification

Magic numbers?Magic numbers? Masses?Masses? Half-lives?Half-lives? Fusion dynamicsFusion dynamics Fission barrierFission barrier Fission pathFission path Shell effectsShell effects Deformation effectsDeformation effects