V.V. Volkov

Competition between complete fusion and quasi-fission in reactions between massive nuclei. The fusion barrier

Abstract A model of the competition between complete fusion and quasi-fission channels in fusion of two massive nuclei is proposed. The calculation of the evaporation residue cross sections in the reactions 100Mo + 100Mo and 110Pd + 0794 0989 110Pd within this model gives a good agreement with the experimental data. The fusion barrier of a new type in the complete fusion of two massive nuclei is revealed.

Fusion cross sections for superheavy nuclei in the dinuclear system concept

Abstract Using the dinuclear system concept we present calculations of production cross sections for the heaviest nuclei. The obtained results are in a good agreement with the experimental data. The experimentally observed rapid fall-off of the cross sections of the cold fusion with increasing charge number Z of the compound nucleus is explained. Optimal reactions for the synthesis of the superheavy nuclei are suggested.Using the dinuclear system concept we present calculations of production cross sections for the heaviest nuclei. The obtained results are in a good agreement with the experimental data. The experimentally observed rapid fall-off of the cross sections of the cold fusion with increasing charge number

Transfer reactions in the interaction of 40Ar with 232Th

Z

Treatment of competition between complete fusion and quasifission in collisions of heavy nuclei

of the compound nucleus is explained. Optimal experimental conditions for the synthesis of the superheavy nuclei are suggested.

New isotopes29,30Mg, 31,32,33Al, 33,34,35,36Si, 35,36,37,38P, 39,40S and 41,42Cl produced in bombardment of a 232Th target with 290 MeV 40Ar ions

Abstract Transfer reactions in the bombardment of a 232 Th target with 297 MeV and 388 MeV 40 Ar ions have been studied. The energy spectra, angular distributions and the cross sections for the formation of products having atomic numbers 5 ≦ Z ≦ 20 have been measured. In the energy spectra of the reaction products broad peaks having energies in the vicinity of the output Coulomb barrier height have been observed along with the quasi-elastic ones. The dependence of the partial angular distribution of the light products on the reaction Q -value has been determined. The observed partial angular distributions have been analysed by applying the Strutinsky model. The total cross sections of light product formation have been found to be 1100 mb and 2400 mb for the 40 Ar energies E = 297 MeV and E = 388 MeV, which give the values of the critical angular momentum of 102 ħ and 94 ħ respectively for the two cases.

On some regularities in multinucleon transfer reactions with heavy ions

A model of competition between complete fusion and quasifission channels in fusion of two massive nuclei is extended to include the influence of dissipative effects on the dynamics of nuclear fusion. By using the multidimensional Kramers-type stationary solution of the Fokker-Planck equation, the fusion rate through the inner fusion barrier in mass asymmetry is studied. Fusion probabilities in symmetric 90Zr+90Zr, 100Mo+100Mo, 110Pd+110Pd, 136Xe+136Xe, almost symmetric 86Kr+136Xe and 110Pd+136Xe reactions are calculated. An estimation of the fusion probabilities is given for asymmetrical 62Ni+208Pb, 70Zn+208Pb, 82Se+208Pb, and 48Ca+244Pu reactions used for the synthesis of new superheavy elements.A model of competition between complete fusion and quasifission channels in fusion of two massive nuclei is extended to include the influence of dissipative effects on the dynamics of nuclear fusion. By using the multidimensional Kramers-type stationary solution of the Fokker-Planck equation, the fusion rate through the inner fusion barrier in mass asymmetry is studied. Fusion probabilities in symmetric 90Zr+90Zr, 100Mo+100Mo, 110Pd+110Pd, 136Xe+136Xe, almost symmetric 86Kr+136Xe and 110Pd+136Xe reactions are calculated. An estimation of the fusion probabilities is given for asymmetrical 62Ni+208Pb, 70Zn+208Pb, 82Se+208Pb, and 48Ca+244Pu reactions used for the synthesis of new superheavy elements.

Multinucleon transfer reactions in the 232Th+22Ne system

Abstract 17 new nucleides: 29,30Mg, 31,32,33Al, 33,34,35,36Si, 35,36,37,38P, 39,40S and 41,42C together with other, already known nucleides, have been detected and identified in bombardment of a 232Th target with 290 MeV 40Ar ions. The charged-particle identification system combining the magnetic analysis and the ΔE−E technique has been used. The resolving power of the system was good enough to resolve isotopes of argon.

Identification of charged particles by combination of the magnetic analysis and the ΔE, E method

Abstract Multinucleon transfer reactions have been investigated by bombarding 232 Th and 197 Au targets with 137 MeV 16 O ions. An exponential yield dependence on the Q -values was observed for nucleon exchange reactions.

Evidence for particle instability of 10He

Abstract Energy spectra of 58 light particles (Z = 3–12) produced in the bombardment of 232Th with 174 MeV 22Ne ions were measured. The kinematics of the two-body reactions leading to the production of these particles is examined in the framework of the model of Siemens, Bondorf, Gross and Dickmann. The phenomenological systematics of the cross sections, covering the whole set of the experimental data, is presented.

New isotopes 21N, 23O, 24O and 25F, produced in nuclear reactions with heavy ions

Abstract A new method for detecting nuclear reaction products with Z ≲ 10 is described where the combination of the magnetic analysis and the ΔE , E method has been applied. The use of a telescope consisting of thin and thick detectors in the output focus of the magnetic analyzer eliminates the ambiguity of particle identification with magnetic analyzer due to various charge states and improves the mass resolution of the ΔE , E method.