For the production of polarized electrons GaAs cathodes are a suitable candidate. However, their operation lifetime, is limited due to a required coating, which gets destroyed while in operation. One of the limiting factors is called Ion-Back-Bombardment. There residual gas molecules gets ionized by the extracted electrons and get accelerated backwards onto the cathode. The dependency of this effect from the used acceleration voltage will be investigated in this bachelor thesis. Therefore multiple simulations will be conducted systematically to calculate how many ions are produced and how far they penetrate into the cathode surface. The results will be compared to experimental observations, conducted at the test stand Photo-Catch.