REACTION MECHANISM STUDY USING TOTAL KINETIC ENERGY AND PRESCISSION PARTICLE MULTIPLICITY IN MEDIUM MASS NUCLEI

K. Yuasa-Nakagawa1, T. Nakagawa1, K. Yoshida1, X. Liu2, S. M. Lee2, D. X. Jiang2, Y. Aoki3, J. Kasagi3, K. Furutaka4

1 The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako, Saitama 351-01, Japan,
2 Institute of Physics, University of Tsukuba, Ibaraki 305, Japan,
3 Laboratory of Nuclear Science, Tohoku University, Sendai, Miyagi 982, Japan,
4 Japan Atomic Energy Research Institute, Tokai, Ibaraki 319-11, Japan


We measured g-ray multiplicity and light charged particle (LCP) multiplicity simultaneously in coincidence with binary decay fragments in the reaction of 84Kr + 27Al at the incident energy of 8.5 MeV/nucleon. We observed the prescission LCP multiplicities and total kinetic energy (TKE) of heavy fragments as a function of the angular momentum of the system applying the measured g-ray multiplicity as an angular momentum filter. For this reaction the fusion-fission process seems to occur dominantly only at the angular momentum ~70h/, which is concluded from the dependence of prescission proton multiplicity on the TKE. The charge distribution of binary decay fragments changes from the symmetric mass division to asymmetric one with increasing the g-ray multiplicity.