Orientation effects of deformed U target nuclei on the fusion probability for the heavy element synthesis

Nishio, Katsuhisa   ; Hofmann, S.*; Ikezoe, Hiroshi; Heberger, F. P.*; Ackermann, D.*; Antalic, S.*; Comas, V. F.*; Gan, Z.*; Heinz, S.*; Heredia, J. A.*; Khuyagbaatar, J.*; Kindler, B.*; Kojouharov, I.*; Kuusiniemi, P.*; Lommel, B.*; Mann, R.*; Mazzocco, M.*; Mitsuoka, Shinichi; Nagame, Yuichiro ; Otsuki, Tsutomu*; Popeko, A. G.*; Saro, S.*; Schtt, H. J.*; Sulignano, B.*; Svirikhin, A.*; Tsukada, Kazuaki  ; Yeremin, A. V.*

The effects of the orientation of the deformed U target nuclei were investigated in the reaction of Si+U. The cross-sections of the system to overcome the Coulomb barrier were determined by measuring the fission cross-sections at JAEA-tandem accelerator, from which the Coulomb barrier height for the collision of Si to the polar side and the equatorial side of U were determined. The evaporation residue (ER) cross-sections were determined at the velocity filter SHIP of GSI. Significant enhancement of the cross-sections of Sg(4n) in the sub-barrier energy indicates the lowering of the Coulomb barrier at the Polar collisions. However, competition between fusion and quasifission was implied. The cross-sections for Sg(5n) measured at the above barrier energy indicated that there is no significant fusion hindrance at the equatorial collisions. In this contribution, the systematic behavior of the orientation effects of U is discussed by using additionally the data of O+U and Ca+U.