Abstract. The paper presents results from computer simulations performed on a model of an RF electron source for the Laser Compton Scattering (LCS) γ-ray system. The new LCS γ-ray system is under implementation at ELI-NP/IFIN-HH. Different configurations of the system modelled with the ASTRA software package and different setings on the system components were analysed to optimize the inital beam parameters before acceleration up to ultra-relativistic energy in linac. The properly designed RF electron source contibutes significantly towards delivery a high brightness beam, which is a crucial specification for the LCS γ-rays systems.

Key words: RF electron accelerator, LCS γ-ray system, compter simulations with ASTRA, modelling of electron beam, S-band RF system.