Induced fission studies of Z 82 nuclei at the JAEA Tandem Facility

Smallcombe, J. ; Nishio, Katsuhisa   ; Hirose, Kentaro  ; Nishinaka, Ichiro; Makii, Hiroyuki   ; Orlandi, R.   ; Tamura, Nobuyuki*; Goto, Shinichi*; Otsuki, Tsutomu*; Andreyev, A.*; Tsekhanovich, I.*

Recent -delayed fission studies of proton rich Hg showed the fission to be dominated by asymmetric fragment masses, in contrast to initial predictions. Models of the potential-energy surface for the path toward scission showed a lower fission barrier for an asymmetrically deformed Hg volume. As a probe of this theoretical interpretation, fission of Hg was induced through the symmetric reaction ZZ. Mass and energy distributions of fragments for a series of bombarding energies were recorded using 2 MWPCs. As a continuation of Z fission studies, fission induced in the LiW reactions were measured. Near A190 a new region of asymmetric fission is predicted to emerge as one moves towards neutron rich nuclei. In preliminary investigations mass asymmetry was observed in fragments of the LiW reaction. However, fragment kinematics were inconsistent with fission of Ir formed by fusion. A follow up experiment was conducted in an attempt to confirm the first observation of fission induced by the Li breakup-fusion reaction WLi,HeRe. Experimental details and initial results will be presented.