In this paper, the effective Parameters in the confinement and trapping of fast electrons in plasma source Such as; plasma pressure, wall material of plasma chamber and magnetic mirror rate have been investigated with using Comsol & Geant4 code. The calculations are shown that the Multicusp magnetic field was effective the pressure less than 5 mTor, and the confinement effect becomes stronger with decreasing pressure. It is equivalent to a higher yield of output ions of plasma source. The number of fast electrons trapped in the magnetic field increases with increasing magnetic field intensity and using aluminum for wall material. Optimum conditions of confinement plasma, leading to increased the hot electron density, and ionization efficiency is increased. The results of investigations have demonstrated good correspondence with theoretical calculations, therefore there is the adequacy of the developed approach and the possibility to build more effective source ion on this basis.