The ongoing research at Texas A&M University (TAMU) aims to develop and implement measurement techniques to quantify fission product transport and related phenomena in a Gas-Cooled Fast Reactor (GCFR). This study summarizes the experimental measurements performed in a Proof-of-Concept Facility (PCF) to understand particle transport under various Reynolds numbers. Using high-resolution high-magnification optical measurement techniques, surrogate particle deposition was measured on the bottom wall surface of the PCF. The particle deposition over time was observed to decrease as the Reynolds number increased. In addition, the particle spatial distributions increased approaching the side wall of the PCF. This state-of-the art optical technique allows for the non-intrusive measurements of micron-sized particles near the wall surface.