Study of fission using multi-nucleon transfer reactions

多核子移行反応を用いた核分裂の実験研究

西尾 勝久   ; 廣瀬 健太郎  ; Vermeulen, M. J.; 牧井 宏之   ; Orlandi, R.  ; 塚田 和明  ; 浅井 雅人  ; 豊嶋 厚史; 佐藤 哲也   ; 永目 諭一郎 ; 千葉 敏; 有友 嘉浩*; 田中 翔也*; 大槻 勤*; Tsekhanovich, I.*; Petrache, C. M.*; Andreyev, A. N.

Nishio, Katsuhisa; Hirose, Kentaro; Vermeulen, M. J.; Makii, Hiroyuki; Orlandi, R.; Tsukada, Kazuaki; Asai, Masato; Toyoshima, Atsushi; Sato, Tetsuya; Nagame, Yuichiro; Chiba, Satoshi; Aritomo, Yoshihiro*; Tanaka, Shoya*; Otsuki, Tsutomu*; Tsekhanovich, I.*; Petrache, C. M.*; Andreyev, A. N.

We are promoting a study of fission using multi-nucleon transfer (MNT) reactions, where excited states in neutron-rich actinide nuclei, which cannot be accessed by particle capture and/or fusion reactions, are populated. Also, the excited states in the fissioning nucleus are widely populated by the MNT reactions, from which effects of excitation energy on fission properties can be investigated. Experiments were carried out at the JAEA tandem facility in Tokai, Japan. We studied reactions using the O beam and several actinide target nuclei such as Th, U, Np, Cm. Ejectile nucleus was identified by a silicon E-E telescope to identify transfer channel and hence the compound nucleus. Fission fragments were detected by multi-wire proportional counters, and fission fragment mass distributions (FFMDs) were measured for each isotope. Measured FFMDs are reproduced by a calculation based on the fluctuation-dissipation model, and importance of multi-chance fission concept is investigated. Fission fragment angular distribution relative to the recoil direction suggested the increase of the spin of the fissioning nucleus with the number of transferred nucleons.