Heavy ion nuclear physics in JINR /present and future/ Yuri Oganessian FLNR JINR 28-th of Nucl. Phys. PAC meeting June 19-20, 2008, JINR, Dubna

neutrons protons H. Jensen, E.P. Wigner and M. Goeppert-Mayer Nobel prize 1963 Nuclear shells Heaviest nuclei Exotic area Lightest nuclear ? Yu. Oganessian. Heavy Ion Physics in JINR. 28-th PAC meeting, June 19-20, JINR, Dubna

a giant deformation axes up to 3:1 high temperature T~ few MeV (>10 10 K) huge rotation spin up to 66h After it has been shown that a nucleus can endure and finally survive….

Shells in the light nuclei beams 0.8s0.1s Radioactive ion beams Fe two-proton decay

Neutron-rich unstable nuclei Yu. Oganessian. Heavy Ion Physics in JINR. 28-th PAC meeting, June 19-20, JINR, Dubna

Strangely enough, but all the combinations: 3H, 6He, 8He (beams) + 1H, 2H, 3H (targets) have been studied. Now the structure of the lightest nuclei looks as follows:

no shell effect was observed evidence of shell structure strong shell effect in the “doubly-magic” nucleus unbound S 2n = MeV A.N. Ostrowski et al., HMI 1994 S 2n = -1.2 MeV A.A. Korsheninnikov et al., RIKEN 1994 S 2n = -3.0 MeV G.M. Ter-Akopian et al., FLNR 2008 discovery “di-neutron” in halo-nucleus 6 He FLNR 2001

DIRECT 400-cm cyclotron low energy beam line stable ion beams:7Li 11B, 15N, 18O,…48Ca radioactive ion beams Dubna Radioactive Ion Beams now 6 He: 5·10 7 /s on the target Electron accelerator ISOL now 8He DIRECT High intensity of ACCULINA++ 5·10 9 /s on the target

For the nuclei with large neutron (and proton) excess the shell model does not work. New theoretical concepts require more detailed data on the structure of these nuclei. Development of the DRIBs complex connected with: - an increase in the intensity of stable beams at the U-400M by times - energy variation of the radioactive beams - creation and putting into operation the ACCOULINA-2 will allow us to carry out these investigations much more efficiently.

92 U / T α = 4.5·10 9 y Chart of nuclides 82 Pb / stable Bi Th 102 No / T α ≈ 2 s about 50 years ago… Macroscopic theory (Liquid Drop Model) Spontaneous fission T SF = 2·10 -7 y T SF = y T SF < s

Clusters in the decay modes of the 234 U nucleus 4 He 208 Pb 132 Sn Yu. Oganessian. Heavy Ion Physics in JINR. 28-th PAC meeting, June 19-20, JINR, Dubna

Island of Stability shoal peninsula continent New lands Neutron number P r o t o n n u m b e r Island of Stability shoal peninsula continent New lands LogT 1/2 s 1µs 1s1h 1y 1My Sea of Instability Yu. Oganessian. Heavy Ion Physics in JINR. 28-th PAC meeting, June 19-20, JINR, Dubna

Reactions of synthesis Cold fusion Hot fusion Neutron capture Yu. Oganessian. Heavy Ion Physics in JINR. 28-th PAC meeting, June 19-20, JINR, Dubna

SHE actinides Pb neutrons → Cold fusion protons → Reactions of Synthesis Neutron capture Hot fusion Hot fusion Act.+ 48 Ca Yu. Oganessian. Heavy Ion Physics in JINR. 28-th PAC meeting, June 19-20, JINR, Dubna

SHE Cold & hot fusion cross sections fusion survival

“in flight” separation chemical separation 1985 GSI, Darmstadt, Germany * LBL, UC Berkeley, CA Univ. of Mainz, Germany LANL, Los Alamos, NM EIR, Würenlingen, Switzerland Search for Element 116 in 248 Cm + 48 Ca reaction FLNR, Dubna, Russia * LLNL, Livermore, CA upper limit

48 Ca Enrichment up to 68-70% (Lesnoy) isotope production high flux reactors (Oak Ridge, Dimitrovgrad) isotope enrichment 98-99% S-2 separator (Sarov) New ECR-ion source (GANIL, JINR) New separator & detectors (Dubna, Livermore) New target matter technology of the target preparation – 0.3 mg/cm 2 Separation and detection of superheavy nuclei Efforts focused on the synthesis of SHE REACTOR REGIME ACCELERATORS ISOTOPE ENRICHMENT TARGET TECHNOLOGY NEW RECOIL SEPARATOR

242 Pu, 245 Cm 244 Pu, 248 Cm 237 Np 243 Am 249 Cf Decay chains Decay chains 34 nuclides 85 decay chains was registered 48 Ca + FLNR

Spontaneous fission half lives Actinides Trans-actinides Superheavy nuclei

Alpha-decay energies Theory: I. Muntian, Z. Patyk, A. Sobiczewski, Acta Phys. Pol. B 34 (2003) Experiment: black – light ion induced reactions blue – cold fusion red – Act. + 48Ca reaction Yu. Oganessian. Heavy Ion Physics in JINR. 28-th PAC meeting, June 19-20, JINR, Dubna

cold fusion deformed nuclei spherical nuclei 48 Ca-induced reactions Theory and Experiment

The main prediction of the modern microscopic theory of the atomic nuclei about beginning new nuclear shells with an “Islands of Stability” in the region of hypothetical very heavy (superheavy) elements have been confirmed not only qualitatively but in some sense quantitatively. Then there is a direct way to move further, to the region of heavier nuclei, to the study of fundamental properties of atomic nuclei which have been previously inaccessible.

Within 6 years: In 26 experiments aimed at the synthesis of superheavy elements a 48Ca total beam dose of 2.2∙10 20 was collected. At an average beam intensity of 0.5 pµA (so far it is record) the irradiation of targets lasted non-stop for 3 years! Now at an average beam current of 5 pµA (which is feasible at accelerators and methodologically accepted) these experiments will only take no longer than 1/2 years! Limiting the number of the experiments (the line of research is clear), increasing the beam intensity and putting into operation new effective set-ups one can increase the sensitivity by times!

It definitely brings not only a qualitative leap in the setting of experiments previously inaccessible, but opens up absolutely new pages in the studies of nuclear and atomic structures.

Nuclear density of the SHE was produced in 249 Cf+ 48 Ca reaction α α α α n n n Z=120, A= α-particles + 60 neutrons Yu. Oganessian. Heavy Ion Physics in JINR. 28-th PAC meeting, June 19-20, JINR, Dubna

Cold fusion Act.+ 48 Ca available for chemical studies α-decay

Atomic properties Yu. Oganessian. Heavy Ion Physics in JINR. 28-th PAC meeting, June 19-20, JINR, Dubna

Chemical properties Chemical properties Ca 20 Pu 94 Chemical identification 114 →112→110 decays 86 Rn relativistic Yu. Oganessian. Heavy Ion Physics in JINR. 28-th PAC meeting, June 19-20, JINR, Dubna

Reaction: 242 Pu (48 Ca,3n) [0.5s ]→α→ [3.6s ] Compound Hg(Au) and 112(Au) Compound Hg(Au) and 112(Au) FLNR 2007 Yu. Oganessian. Heavy Ion Physics in JINR. 28-th PAC meeting, June 19-20, JINR, Dubna

Element 112 is a noble metal – like Hg 12 th group of the Periodic Table

Chemical properties Chemical properties Periodic Table of the Chemical Elements

The study of the superheavy element’s atomic structure will show the limits of application of the Periodic law and will reveal new Periodic Table with taking into account the “relativistic” and other effects. It is also possible that these basic regularities can be revealed in the study of already synthesized elements with Z= But in any case, new experiments demand an increase in the productivity of superheavy nuclei by times, at the expense of an increase in the ion beam intensity and creation of more fast methods.

After 50 years of formation of heavy ion physics at the JINR the time has come to make a next step into the future Such steps have already been made in the leading nuclear centers of the world: RIKEN (Japan), GSI (Germany) GANIL (France) this club will definitely be extended by new members The JINR is most prepared for realizing its own scenario of heavy ion physics development; which seems to be very realistic and can be accomplished within short periods of time. We can hold the leading position for the Institute for the near and distant future in this field of physics. Conclusion

Thank you very much for your attention