An exact closed form solution to the time-integrated master equation of the exciton model is applied to the calculation of the angular distribution for both the preequilibrium and equilibrium decays of the neutron-induced reaction. The distribution probability of two-nucleon collision from g2 to f2' based on the Fermi gas model and the influence of the Fermi motion and the Pauli principle on the shape of the angular distribution are studied in detail. We have concluded that the influence of these effects on the shape of the angular distribution is rather significant for reactions in the energy range of several tens of MeV. As an example to compare with the experiments we have calculated the neutron-induced reaction 93Nb(n,n') at E,=15MeV. It seems that the most significant improvement of the present approach is the rise of the backward direction of the double differential cross section for the higher energy emitted neutrons.
To study the descriptions of nuclear pre-equilibrium and equilibrium processes, a unified compound and pre-equilibrium model including not only particles but also -ray emissions is developed. The -ray emission mechanism is studied first. The calculated -ray emission cross-section and spectrum of fast neutron bombarding are in good agreement with experimental data.
For fast neutron-induced reactions for structural materials by using the unified compound pre-equilibrium model, the light composite particles emissions have to be taken into account properly. The mechanism of cluster formation and emission was investigated. Estimated results with considering the secondary emission process were compared with experimental data.
We generalized the time–dependent solution of the Fokker–Planck equation to n degrees of freedom. Using the solution we calculated the extra push energy from the view of Brownian motion as a diffusion process over a saddle point, which is caused by overcoming both repulsive Coulomb and dissipative forces to form a compound nucleus. It depends on the initial condition and the friction, other degrees of freedom acting as a heat bath of temperature T and causing thermal fluctuations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.