An experimentally proven model was proposed stating that vacancies of cadmium atoms were dominating in kernels of the defect clusters formed in single CdS crystals by the irradiation with fast 1MeV reactor neutrons. The so-called sub-threshold effects played the essential role in cluster formation. The sub-threshold effects consequently lead to the excitation and ionization of the K-shell of Cd atoms followed by an increase of charge of Cd ions. This finally result in an ejection of these ions from the kernels to periphery of defect clusters due to the electrostatic force (electrostatic explosion).

Nature of Vacancy Defect Clusters in Chalcogenic Semiconductors of AIIBVI Group Irradiated by Neutrons. G.Y.Davidyuk, V.V.Bozhko, G.L.Myronchuk, A.G.Kevchin, V.Kažukauskas: Physica Status Solidi C, 2009, 6[12], 2804-6