This research is a combined experimental and theoretical study of the deposition of flame generated silica particles onto a thin circular disk or circular cylinder. The theory will include effects of particle inertia, diffusion, thermophoresis, and coagulation on the variation of particle size distributions with position and its influence on the deposition rate. Experiments will measure local aerosol concentration and size distribution and the overall deposition rate will be determined by weight changes of the collectors. The research should provide improved understanding of the vapor axial deposition (VAD) process and the outside vapor deposition (OVD) process for manufacturing optical waveguide preforms and other cases, desired or otherwise, of particle deposition onto surfaces from high temperature gases.