Apparatus for the delivery of a gas to a chamber and methods of use thereof are provided herein. In some embodiments, a gas distribution system for a process chamber may include a body having a first surface configured to couple the body to an interior surface of a process chamber, the body having a opening disposed through the body; a flange disposed proximate a first end of the opening opposite the first surface of the body, the flange extending inwardly into the opening and configured to support a window thereon; and a plurality of gas distribution channels disposed within the body and fluidly coupling a channel disposed within the body and around the opening to a plurality of holes disposed in the flange, wherein the plurality of holes are disposed radially about the flange.