We are building an instrument to study the gas phase reaction dynamics of ions with neutral molecules using conditions similar to the interstellar medium with ions and neutral molecules that are known to exist in space. Specifically, we will be studying the branching ratios of product channels available in these reactions under a variety of temperatures, pressures, and external photon energies that adequately simulate the conditions of the interstellar medium. There are no commercial instruments that can provide all these specific conditions, therefore we are building a custom instrument at IWU. To efficiently build an instrument, often times scientists use simulation programs like SIMION to (1) optimize the use of space and (2) to design the optics to guide the ions as a beam. This program will reduce the time for troubleshooting the instrument, as well as the cost associated with it. The region that needed the most ion optics is near the ion trap where reactions take place. Therefore, a several types of ion optics were explored using SIMION (simulation program) in this study. The final design and current progress of the instrument building will be presented as part of the study.