Pre-scission neutron multiplicity associated with the dynamical process in the superheavy-mass region

The fusion?fission process accompanied by neutron emission is studied in the superheavy-mass region on the basis of the fluctuation?dissipation model combined with a statistical model. The calculation of the trajectory or the shape evolution in the deformation space of the nucleus with neutron emission is performed. Each process (quasi-fission, fusion?fission and deep quasi-fission processes) has a characteristic travelling time from the point of contact of colliding nuclei to the scission point. These dynamical aspects of the whole process are discussed in terms of the pre-scission neutron multiplicity, which depends on the time spent on each process. We have presented the details of the characteristics of our model calculation in the reactions 48Ca + 208Pb and 48Ca + 244Pu, and shown how the structure of the distribution of the pre-scission neutron multiplicity depends on the incident energy.