A new tool to compare neutron and ion irradiation in materials

The slowing down of neutrons produced in nuclear plants or in spallation sources generates many defects in a material, driving this material far from its equilibrium state. This concentration of defects leads to important structural modifications of solids. To model the impact of radiation in solids, particle accelerators are useful tools. The nature and the energy of ions in accelerators must be chosen to produce similar effects to those occurring in nuclear plants. A new program, DART, based on the binary collision approximation, has been developed to optimize the choice of incident particles. In this program, the anisotropy of the neutron atom interaction is treated with a new formalism. Such a formalism allows us to compute accurate displacement cross sections and recoil spectra for all kinds of particles (ions, neutrons, or electrons). The comparison of these displacement cross sections as well as recoil spectra due to ions, electrons and neutrons permits to define the nature and the energy of ions able to simulate damages in reactors.