We present a comparison of the experimental and simulated results of the thermionic hairpin-source, electron beam assembly using the SLAC electron beam trajectory program (EGUN). The gun was optimized for maximum emission current density and beam convergence in the post anode region. Therefore, by optimizing different parameters, an emission current density of 32 A/cm 2 with maximum beam convergence of 0.9 mm was obtained. This corresponds to a power density of 3.29 × 10 5 W/cm 2 at the focus point. As this was accomplished without the aid of magnetic focusing, the assembly was much simplified. The gun can now be used for electron devices and accelerator technology which require high current and power densities.