Competition between fusion-fission and quasifission processes in the S32+W184 reaction

Zhang, H. Q.; Zhang, C. L.; Lin, C. J.; Liu, Z. H.; Yang, F.; Nasirov, A. K.; Mandaglio, G.; Manganaro, M.; Giardina, G.
Bibliographical reference

Physical Review C, vol. 81, Issue 3, id. 034611

Advertised on:
3
2010
Number of authors
9
IAC number of authors
0
Citations
58
Refereed citations
47
Description
The angular distributions of fission fragments for the S32+W184 reaction at center-of-mass energies of 118.8, 123.1, 127.3, 131.5, 135.8, 141.1, and 144.4 MeV are measured. The experimental fission excitation function is obtained. The anisotropy (Aexp) is found by extrapolating each fission fragment angular distribution. The measured fission cross sections of the S32+W182,184 reaction are decomposed into fusion-fission, quasifission, and fast-fission contributions by the dinuclear system model (DNS). The angular momentum distributions of the dinuclear system and compound nucleus calculated by the DNS model are used to reproduce the experimental capture and fusion excitation functions for both reactions and quantities K02, <ℓ2>, and Aexp, which characterize angular distributions of the fission products at the considered range of beam energy. The total evaporation residue excitation function for the S32+W184 reaction calculated in the framework of the advanced statistical model is close to the available experimental data only up to about Ec.m.≈160 MeV. The underestimation of the experimental data at high excitation energies Ec.m.>160 MeV is explained by the fact that the statistical model cannot reproduce the cross section of evaporation residues formed by the nonequilibrium mechanism, that is, without formation of the compound nucleus in the statistical equilibrium state.
Type