Cascade explosion of an atom under ionizing radiation

Abstract

Irradiation of matter with high energy photons or particles may cause inner-shell ionization of atoms. The decay of an innershell vacancy is often called a cascade explosion since it is a complex cascade of radiative and non-radiative transitions leading to emission of photons and electrons, and to multiple ionization. To calculate various characteristics of the decay cascades, we developed an approach based on the straightforward construction of de-excitation trees in the configuration-average Hartree-Fock approximation. This approach was applied to study a) the final-ion-charge spectra of singly ionized, resonantly excited and hollow atoms, b) the cascade-produced electron spectra, c) the cascade-produced emission spectra. Selected results are presented. The role of the cascade explosions of the inner-shell-ionized atoms in the ionizing radiation effect on matter is briefly discussed.