Calculation of displacement cross sections at intermediate and high energies of primary particles using results of molecular dynamics simulations

Abstract

A method combining the intranuclear cascade evaporation model, the binary collision approximation model and the method of molecular dynamics is proposed for the calculation of displacement cross sections for structural materials irradiated with intermediate and high energy particles. Calculated displacement cross sections are compared with experimental data for copper irradiated with 1.1 and 1.94GeV protons. Calculations up to the proton energy 0.1TeV are discussed. Materials of advanced nuclear energy systems as the fusion reactor and ADS are considered to be irradiated by extremely intense fluxes of energetic particles. The study of the radiation damage of structural materials for these facilities relies on the accurate calculation of displacement cross sections at intermediate and high energies. The NRT model (1) is frequently used for the calcu- lation of the damage accumulation in irradiated materials. The relative simplicity of the approach provides its use in widespread codes such as NJOY, MCNPX, and others. Avail- able experimental data (2) and more rigorous calculations show the difference with predictions of the NRT model that makes questionable its use for reliable calculations of the displacement cross section and the radiation damage rate. In the present work the number of defects produced by pri- mary knock on atoms (PKA) in materials is calculated with the help of the binary collision approximation model (BCA) using the results obtained by the method of the molecular dynamics (MD). Calculations of primary recoil spectra are performed using various nuclear models, including the optical model and different versions of intranuclear cascade evaporation model. The displacement cross section is calculated by the for- mula