Studies on mechanism of heavy ion-induced reaction on gold in energy region below 10MeV/u.

摘要

Mechanisms of heavy-ion induced nuclear reactions in mass-asymmetric systems were studied in this study. Especially nucleon transfer reaction and compound formation reaction were investigated.;Excitation functions and projected mean recoil ranges of the target-like products in ;Nucleon transfer reaction was discussed distinguishing the products from quasi-elastic transfer reaction (QET) and those from deep inelastic transfer reaction (DIT). Observations indicate that QET takes place along a trajectory near the Coulomb trajectory. QET are made to be connected with interaction radius and most of the cross section ratios were reproduced well by an extended tunneling model. The tendency towards equilibration of the N/Z value and the energy damping, which are the characteristic features of DIT, are found only in the production of Au isotopes. Damped components of projectile-like products observed were concluded to be produced in a very short interaction time. Cross sections of those products were reproduced by the sum rule model better than by the diffusion model and their total kinetic energies can also be explained well by a model using recoil formula by Siemens et al. with an assumption of short time interaction.;Excitation functions and mean projected recoil ranges of the evaporation residues in ;Fusion cross sections as a sum of cross sections of evaporation residues and that of fission were reproduced well with either of the Bass model or the extra-push model.;Competition between evaporation residue formation and fission process was discussed with a statistical calculation using fission barriers dependent on angular momentum. The excitation functions of fission and particle evaporation were reproduced well by a calculation with fission barriers predicted by the rotating finite range model.;Moreover a simple method based on the statistical model but practically with no fitting processes was described. It enabled us to define a specific J-window for preactinide fissioning systems, to deduce fission barrier B