In but one aspect of the invention, a method of depositing polysilicon comprises providing a substrate within a chemical vapor deposition reactor, with the substrate having an exposed substantially crystalline region and an exposed substantially amorphous region. Part of the first and second linear light is reflected by the reflecting portion and the reflecting surface, and a residual part is diffused and reflected by the diffusion reflecting portion and is emitted from the opening portion. Another safety valve system includes multiple safety valves.