Defect cluster production in the radiation annealing of the Frenkel pairs

Abstract In reactor neutron irradiation the primary knocked-out atom, forming secondary defects and thus slowing down, loses energy in the zone of developing cascade which, when heated to a temperature higher than ambient temperature, provides the migration and annihilation of the Frenkel pairs and their coagulation which results from heavy defect supersaturation. An equation expressed in partial derivatives with respect to time and cluster multiplicity has been derived describing the kinetics of cluster formation in the cascades produced by the primary knocked-ut atoms having arbitrary energy. The solution of the equation gives the dependence of the cluster concentration and multiplicity in the cascade zone on the initial energy of the slowing down atom. Formulas describing the amount of clusters produced by the primary knocked-out atom in the initial ideal material have been derived for the case of loop dislocation (extraplanes) and for the case of spherical vacancy clusters.