In-beam fissio study at JAEA for heavy element synthesis

Nishio, Katsuhisa   ; Ikezoe, Hiroshi; Hofmann, S.*; Ackermann, D.*; Aritomo, Yoshihiro*; Comas, V. F.*; Dllmann, Ch. E.*; Heinz, S.*; Heredia, J. A.*; Heberger, F. P.*; Hirose, Kentaro*; Khuyagbaatar, J.*; Kindler, B.*; Kojouharov, I.*; Lommel, B.*; Makii, Hiroyuki   ; Mann, R.*; Mitsuoka, Shinichi; Nishinaka, Ichiro; Otsuki, Tsutomu*; Saro, S.*; Schdel, M.*; Popeko, A. G.*; Trler, A.*; Wakabayashi, Yasuo; Watanabe, Yoshio*; Yakushev, A.*; Yeremin, A.*

Fission fragment mass and kinetic energies distributions were measured in the heavy-ion induced reactions using U target nucleus at the energies around the Coulomb barrier. We observed strong variation of the fragment mass distribution with incident energy, which was explained by an energy dependence of the probabilities for fusion and quasifission. A calculation based on a fluctuation-dissipation model was carried out to determine the fusion probability in the reactions of Si+U and S+U. The fusion probabilities were consistent with those determied from the evaporation residue cross sections for both reactions, showing that in-beam fission measurement and analysis can give a reasonable estimation for the cross sections to produce super-heavy nuclei. We also discss the results for in-beam fission measurement of Ca+U.