Evidence of quasifission in the Hg composite system formed in the Zn + Sn reaction
E.M. Kozulin (Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna, Russia)
; E. Vardaci (Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Napoli, Italy, Dipartimento di Fisica “E. Pancini”, Universita degli Studi di Napoli “Federico II”, Napoli, Italy); W.H. Trzaska (Department of Physics, University of Jyväskylä, Jyväskylä, Finland); A.A. Bogachev (Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna, Russia); I.M. Itkis (Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Dubna, Russia); et al - Show all 8 authors
For the $^{68}$Zn + $^{112}$Sn reaction the Coulomb parameter is equal to 1500 that is close to the threshold value for the appearance of quasifission process. It was found that mass-energy distributions of the reaction fragments differ significantly from those obtained in the $^{36}$Ar + $^{144}$Sm reaction leading to the formation of the same composite system of $^{180}$Hg at similar excitation energies of about 50 MeV. In the case of the reaction with $^{68}$Zn ions, the mass distribution of fissionlike fragments has a wide two-humped shape with maximum yields at 70 and 110 u for the light and heavy fragments, respectively, instead of 80 and 100 u observed in the fission of $^{180}$Hg formed in the $^{36}$Ar + $^{144}$Sm reaction. The difference is explained by an unexpectedly large contribution (more than 70%) of quasifission in the case of the $^{68}$Zn + $^{112}$Sn reaction.
