Abstract: In the infrared gas analyzers described in the specification, infrared radiation is transmitted through a measuring cell to an infrared detector. The measuring cell has an external case and a tubular filter to remove particulate material from the gas being analyzed immediately before it is intercepted by the infrared radiation.

Abstract: Disclosed are method and apparatus for producing amorphous silicon layers for solar cells or electrophotography by plasma-enhanced chemical vapor deposition (CVD) through glow-discharge decomposition of a reaction gas containing monosilane or a higher order silicon hydride in a reaction chamber. Deposition rate and efficiency of reaction gas usage are improved by the selective removal of hydrogen gas reaction product from the reaction chamber. In one embodiment, a filter which is more permeable to hydrogen gas than to the reaction gas is placed in the vacuum pumping port of the reaction chamber. The filter comprises either a palladium film or a bundle of small diameter tubes made from a polyimide system polymer. In another embodiment of the invention, a porous sintered material containing La-Ni alloy is used to selectively adsorb hydrogen gas in the reaction chamber.