Abstract
The microscopic description of nuclear fission still remains a topic of intense basic research. Understanding nuclear fission, apart from a theoretical point of view, is of practical importance for energy production and the transmutation of nuclear waste. In nuclear astrophysics, fission sets the upper limit to the nucleosynthesis of heavy elements via the process. In this work we initiated a systematic study of intermediate-energy proton-induced fission using the constrained molecular dynamics (CoMD) code. The CoMD code implements an effective interaction with a nuclear matter compressibility of (soft equation of state) with several forms of the density dependence of the nucleon-nucleon symmetry potential. Moreover, a constraint is imposed in the phase-space occupation for each nucleon restoring the Pauli principle at each time step of the collision. A proper choice of the surface parameter of the effective interaction has been made to describe fission. In this work, we present results of fission calculations for proton-induced reactions on: (a) at 27 and 63 MeV; (b) at 10, 30, 60, and 100 MeV; and (c) at 100 and 660 MeV. The calculated observables include fission-fragment mass distributions, total fission energies, neutron multiplicities, and fission times. These observables are compared to available experimental data. We show that the microscopic CoMD code is able to describe the complicated many-body dynamics of the fission process at intermediate and high energy and give a reasonable estimate of the fission time scale. Sensitivity of the results to the density dependence of the nucleon symmetry potential (and, thus, the nuclear symmetry energy) is found. Further improvements of the code are necessary to achieve a satisfactory description of low-energy fission in which shell effects play a dominant role.
9 More- Received 15 November 2014
- Revised 10 July 2015
DOI:https://doi.org/10.1103/PhysRevC.92.024616
©2015 American Physical Society