A process chamber comprising can include a curved upper wall extending longitudinally from a first end portion of the reaction chamber to a second end portion of the reaction chamber. The process chamber can include a curved lower wall cooperating with the curved upper wall to at least partially define an internal cavity, the curved lower wall connected to the curved upper wall from the first end portion to the second end portion at a first side of the reaction chamber and at a second side of the reaction chamber. A rail can extend along an exterior surface of the process chamber from the first end portion to the second end portion, the rail disposed at or near a connection between the curved upper wall and the curved lower wall.