Photon production using a low energy electron expansion of the EGS4 code system

An expansion of the EGS4 code system has been developed in which electron-atom inelastic collisions are modelled taking into account atomic bound effects. Additional models have been developed to deal with the ionisation of the K-shell and improved angular sampling of newly created bremsstrahlung photons. The incorporation of these features in EGS4 is described and the updated code is used to simulate photon generation in X-ray tubes. The accuracy of the new code and some of its possible applications are discussed.