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Average preequilibrium npreeq> average statistical prescission nstpre> and postscission npost> neutron multiplicities as well as average γ-ray multiplicity , average energy emitted by γ-rays and average energy per one gamma quantum <[variant_greek_epsilon]γ> as a function of mass and total kinetic energy (TKE) of fission fragments were measured in the proton-induced reactions p+232Th→233Pa, p+238U→239Np and p+242Pu→243Am (at proton energy Ep=13, 20, 40 and 55 MeV). The fragment mass and energy distributions (MEDs) have been analyzed in terms of the multimodal fission. The decomposition of the experimental MEDs onto the MEDs of the distinct modes has been fulfilled in the framework of a method that is free from any parameterization of the distinct fission mode mass distribution shapes. The main characteristics for symmetric and asymmetric modes have been studied in their dependence on the compound nucleus composition and proton energy. The manifestation of multimodal fission in average γ-ray multiplicities of fission fragments was also studied in this work. © 2007 American Institute of Physics [ABSTRACT FROM AUTHOR]

Mass, energy and folding angle distributions of the fission fragments as well as multiplicities of neutron and gamma-quanta emissions accompanying the fission process were measured for fission of 226Th, 227Pa and 234Pu compound nuclei produced in reactions with 18O and 26Mg projectiles over a wide energy range. Data were analyzed with respect to the presence of fission modes. Asymmetric fission was observed even at very high initial excitation for all the measured systems. The so-called fission mode S1 (caused by the proton shell Z∼50 and neutron shell N∼82 in heavy fragment) was found to be dominant in asymmetric fission of 234Pu. Reactions with not full linear momentum transfer were observed in the folding spectra for all the measured systems. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The fusion-fission process for the synthesis of superheavy elements is discussed on the basis of the fluctuation-dissipation model. Recently the experiments at Dubna on fission of superheavy nuclei were carried out, and the mass and total kinetic energy distributions of fission fragments were measured. By analyzing the mass distribution of fission fragments, we can distinguish between fusion-fission process and quasi-fission process. We employ three-dimensional Langevin equation. We find almost all of the mass symmetric fission events come from the quasi-fission process in the superheavy mass region. In order to classify the fusion-fission paths and compare with the experimental data directly, we analyze the pre-scission neutron emission in the correlation with fission fragments. The neutron multiplicity depends on the travelling time of the trajectory. It is useful to investigate the fusion-fission process. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]