Implementation of electron-impact ionization into the EGS4 code

A modification to the general-purpose Monte-Carlo electron–photon transport code EGS4 [1]was made in order to include K-shell electron-impact ionization (EII). Five cross sections of K-shell EII have been implemented. The ratio of the K-shell EII cross section to the Møller scattering cross section is prepared by the PEGS4 program, and is then used in the EGS4 code. Simulations of the K–X-ray emissions from Al, Ti, Cu, Sn, Ag and Au targets for an electron beam with an incident energy of 0.01 to 3 MeV were performed by using the improved EGS4 code; the calculated K–X-ray yields agreed well with the measurements.