Abstract: At least one gaseous impurity, for example silane, is removed by absorption from a feed gas stream, for example a gas stream comprising nitrogen and hydrogen, the gaseous impurity being less volatile than the feed gas stream. The absorption is effected by a sub-cooled absorbent at a first cryogenic temperature and a first pressure. The absorbent is typically propane. The absorption may be conducted in a liquid-vapor contact column (130). Absorbent containing impurity may be regenerated in a regeneration vessel 150 and returned to the column (130).

Abstract: Apparatus for treating a gas stream comprises a plurality of cylindrical proton conducting membranes. The gas stream is conveyed through the bore of each cylindrical membrane, and a hydrogen-containing gas is conveyed about the external surface of each cylindrical membrane. A catalyst provided on the inner side of each membrane catalyses a reaction between a halogen-containing component of the gas stream, such as CF4, adsorbed on the surface of the catalyst and protons conducted through the membrane.

Abstract: A vacuum pumping arrangement is described for pumping a gas stream containing hydrogen or other hydrogen-containing gas. The arrangement comprises a pumping mechanism for receiving the gas stream and exhausting a pumped gas stream at a sub-atmospheric pressure, and, downstream from the pumping mechanism, an ionic conducting membrane having one side exposed to the pumped gas stream and another side exposed to oxygen or other source of oxygen. In one example, the membrane is permeable to hydrogen, which permeates across the membrane to react with oxygen adsorbed on the other surface of the membrane. In another example, the membrane is permeable to oxygen anions, which permeate across the membrane to react with hydrogen within the gas stream.

Abstract: An apparatus for treating a gas stream comprises a nonthermal plasma reactor, for example a dielectric barrier discharge plasma reactor, containing a silicon-containing solid for reacting with a halogen-containing component of the gas stream to form a gaseous silicon halide. A sorbent bed of material chosen to react with the silicon halide to form inorganic halides is located downstream from the plasma reactor. A similar bed of material is located upstream from the plasma reactor to remove silicon halide and other acid gas components from the gas stream before it enters the plasma reactor.

Abstract: A method is described for recycling hydrogen (H2) supplied to a chamber (10) in a gas stream comprising hydrogen and at least one other gas, such as silane. A gas comprising at least hydrogen is drawn from the chamber (10) using a first vacuum pump (32) that exhausts gas therefrom at a sub-atmospheric pressure. A portion of the gas exhausted from the first vacuum pump (32), for example between 70 and 95% of this gas, is diverted away from a second vacuum pump (34) backing the first vacuum pump (32). In one embodiment, the diverted portion of the sub-atmospheric pressure gas is treated to produce a purified gas comprising hydrogen, which is stored in a storage vessel (14). The composition of the purified gas is analysed, and, depending on the results of the analysis, at least one of hydrogen and silane is added to the stored gas so that the composition of the stored gas is similar to that of the gas initially supplied to the chamber (10). Gas is then supplied to the chamber (10) from the storage vessel (14).

Abstract: The method of recovery and recycling of inert gases, especially noble gases, from processes such as vacuum furnaces and other applications. A first gas stream comprising the inert gas and oxidisable impurities, is supplied to an oxidation column comprising a metal oxide. The impurities in the first gas stream are oxidised in the column in the presence of the metal oxide to form a second gas stream containing carbon dioxide and water, the second gas stream is supplied to a regenerable carbon dioxide removal column; the carbon dioxide is removed from the second gas stream in the column to form a third gas stream. Water is removed from the third gas stream in an absorption column, and the exhausted, purified inert gas is collected from the absorption column for conveying to a process utilising the inert gas. The recovered gas stream is of around 6N purity (99.9999% pure) i.e. having 1 ppm total contaminants.

Abstract: At least one gaseous impurity, for example silane, is removed by absorption from a feed gas stream, for example a gas stream comprising nitrogen and hydrogen, the gaseous impurity being less volatile than the feed gas stream. The absorption is effected by a sub-cooled absorbent at a first cryogenic temperature and a first pressure. The absorbent is typically propane. The absorption may be conducted in a liquid-vapour contact column (130). Absorbent containing impurity may be regenerated in a regeneration vessel 150 and returned to the column (130).

Abstract: A purifier is described for use in a gas processing application. The purifier comprises a chamber having a gas inlet and a gas outlet. A series of baffles are arranged in the chamber and coated with a getter material selected for its ability to react with species to be removed from a gas stream and form stable compounds. The chamber also houses a source of the getter material, which is periodically activated to refresh the coating of getter material on the baffles.

Abstract: A vacuum pumping arrangement is described for pumping a gas stream containing hydrogen or other hydrogen-containing gas. The arrangement comprises a pumping mechanism for receiving the gas stream and exhausting a pumped gas stream at a sub-atmospheric pressure, and, downstream from the pumping mechanism, an ionic conducting membrane having one side exposed to the pumped gas stream and another side exposed to oxygen or other source of oxygen. In one example, the membrane is permeable to hydrogen, which permeates across the membrane to react with oxygen adsorbed on the other surface of the membrane. In another example, the membrane is permeable to oxygen anions, which permeate across the membrane to react with hydrogen within the gas stream.

Abstract: Apparatus for treating a gas stream comprises a plurality of cylindrical proton conducting membranes. The gas stream is conveyed through the bore of each cylindrical membrane, and a hydrogen-containing gas is conveyed about the external surface of each cylindrical membrane. A catalyst provided on the inner side of each membrane catalyses a reaction between a halogen-containing component of the gas stream, such as CF4, adsorbed on the surface of the catalyst and protons conducted through the membrane.

Abstract: An organic contaminant molecule sensor is described for use in a low oxygen concentration monitored environment. The sensor comprises an electrochemical cell, which is formed from a measurement electrode coated with (or formed from) a catalyst having the ability to catalyse the dissociative adsorption of the organic contaminant molecule, the electrode being positioned for exposure to the monitored environment, a reference electrode coated with (or comprised from) a catalyst selected for its ability to catalyse the dissociation of oxygen to oxygen anions, the reference electrode being positioned within a reference environment, and a solid state oxygen anion conductor disposed between and bridging the measurement and reference electrodes, wherein oxygen anion conduction occurs at or above a critical temperature, Tc. Sealing means are provided for separating the reference environment from the monitored environment.

Abstract: Apparatus for treating a gas stream comprises a plurality of cylindrical proton conducting membranes. The gas stream is conveyed through the bore of each cylindrical membrane, and a hydrogen-containing gas is conveyed about the external surface of each cylindrical membrane. A catalyst provided on the inner side of each membrane catalyses a reaction between a halogen-containing component of the gas stream, such as CF4, adsorbed on the surface of the catalyst and protons conducted through the membrane.

Abstract: Apparatus for treating a gas stream comprises a nonthermal plasma reactor, for example a dielectric barrier discharge plasma reactor (30), containing a silicon- containing solid for reacting with a halogen-containing component of the gas stream to form a gaseous silicon halide. A sorbent bed (60) of material chosen to react with the silicon halide to form inorganic halides is located downstream from the plasma reactor. A similar bed (50) of material is located upstream from the plasma reactor to remove silicon halide and other acid gas components from the gas stream before it enters the plasma reactor.

Abstract: A method is described for recycling hydrogen (H2) supplied to a chamber (10) in a gas stream comprising hydrogen and at least one other gas, such as silane. A gas comprising at least hydrogen is drawn from the chamber (10) using a first vacuum pump (32) that exhausts gas therefrom at a sub-atmospheric pressure. A portion of the gas exhausted from the first vacuum pump (32), for example between 70 and 95% of this gas, is diverted away from a second vacuum pump (34) backing the first vacuum pump (32). In one embodiment, the diverted portion of the sub-atmospheric pressure gas is treated to produce a purified gas comprising hydrogen, which is stored in a storage vessel (14). The composition of the purified gas is analysed, and, depending on the results of the analysis, at least one of hydrogen and silane is added to the stored gas so that the composition of the stored gas is similar to that of the gas initially supplied to the chamber (10). Gas is then supplied to the chamber (10) from the storage vessel (14).

Abstract: A method is described of controlling contamination of a surface exposed to a carbonaceous material and ionising radiation, such as EUV radiation, DUV radiation or electrons. The method comprises cyclically supplying to the surface a first gas comprising an oxidising species, for example NO, for reacting with carbonaceous deposits formed on the surface from the carbonaceous material, followed by a second gas comprising a reducing species, for example CO, for reacting with oxidising species on the surface.

Abstract: A system for pumping a gas stream containing a combustible gas comprises a solid oxide ionic conducting membrane (20) and a vacuum pump (36) for drawing the gas stream at a sub-atmospheric pressure to one side of the membrane. The other side of the membrane is exposed to an oxidising gas, and a potential difference is applied across the membrane so that reactive oxidising species permeate across the membrane to react with the combustible gas to produce at least water vapour. The gas stream is subsequently received by the vacuum pump (36). The vacuum pump may have a pumping mechanism that exposes the gas stream to water and wherein the water vapour is condensed from the gas stream. Alternatively, a condenser (14) may be provided between the pump and the membrane for condensing the water vapour from the gas stream.

Abstract: Apparatus for treating a gas stream comprises a plurality of cylindrical proton conducting membranes. The gas stream is conveyed through the bore of each cylindrical membrane, and a hydrogen-containing gas is conveyed about the external surface of each cylindrical membrane. A catalyst provided on the inner side of each membrane catalyses a reaction between a halogen-containing component of the gas stream, such as CF4, adsorbed on the surface of the catalyst and protons conducted through the membrane.

Abstract: A method is described for recovering a noble gas, such as xenon or krypton, from a first gas mixture comprising a plurality of components, one of which is the noble gas and the others are typically helium and/or nitrogen, argon, and relatively light fluorocarbons. The gas mixture is first conveyed to a gas chromatography column for separating the noble gas from the other components of the gas mixture. As the noble gas travels relatively slowly through the column, the other components are exhausted from the column before the relatively slow noble gas. Following the exhaust of these other components, a purge gas is supplied to the column to flush the noble gas therefrom. A second gas mixture comprising the noble gas and the purge gas is conveyed from the column to a membrane separator to separate the second gas mixture into a noble gas-rich gas stream and a purge gas-rich gas stream, which may be recirculated back to the column for re-use.

Abstract: A vacuum pumping system comprises a first gas supply for supplying a first gas, such as xenon, to a vacuum chamber. A pump receives the gas output from the chamber. A second gas supply supplies a purge gas, such as nitrogen or helium, for pumping with the first gas. A gas separator receives the pumped gases exhausted by the pump, and recovers the first gas and the purge gas from the stream. The recovered first gas is recirculated through the vacuum chamber, and the recovered second gas is recirculated through at least the pump.

Abstract: A method is described for recovering a noble gas, such as xenon or krypton, from a first gas mixture comprising a plurality of components, one of which is the noble gas and the others are typically helium and/or nitrogen, argon, and relatively light fluorocarbons. The gas mixture is first conveyed to a gas chromatography column for separating the noble gas from the other components of the gas mixture. As the noble gas travels relatively slowly through the column, the other components are exhaust from the column before the relatively slow noble gas. Following the exhaust of these other components, a purge gas is supplied to the column to flush the noble gas therefrom. A second gas mixture comprising the noble gas and the purge gas is conveyed from the column to a membrane separator to separate the second gas mixture into a noble gas-rich gas stream and a purge gas-rich gas stream, which may be recirculated back to the column for re-use.