On the Assessment of Radiation Resistance of Materials in Imitation Experiments

The theoretical and experimental data determining the similarities and differences between the defect formation processes under the conditions of neutron and imitation ion irradiation are analyzed. The analysis involves such factors as the type and energy of cascade-forming particles, the composition and structure of irradiated materials, and the irradiation temperature. A number of proven procedures for calculating the concentration of radiation defects and the number of displacements per atom for cascade-forming types of irradiation are revised. The key factors ensuring the similarity of full-scale and simulation experiments are considered, with the following two of them singled out as the principal factors: the damaging dose accumulation rate (flux) and the temperature, which determine the course of relaxation processes. Simple methods are proposed for estimating the number of primary knocked-on atoms (PKA) under neutron irradiation and the fraction of elastic energy losses spent on defect formation. The substantiation of a unified fractal structure of atomic displacement cascades in a given target is provided, regardless of the nature and energy of the cascade-forming types of irradiation.