Abstract: A detector comprising an analytical apparatus for detecting a substance of interest, and a detector inlet. The detector inlet comprises a flow passage for carrying a flow of fluid, the flow passage comprising a sampling volume, and a sampling inlet adapted to collect samples of the fluid from the sampling volume as the fluid flows past the sampling inlet, and to provide the samples to the analytical apparatus, wherein the flow of fluid carries particulates. The detector inlet also comprises a flow director arranged to vary a spatial distribution of the particulates carried by the fluid to increase a relative proportion of the particulates carried past the sampling inlet along the flow passage without entering the sampling volume.

Abstract: A detector inlet for providing a sample to an analytical apparatus for detecting an aerosol, the detector inlet comprising; an intake for inhaling a flow of gaseous fluid to be sampled by the analytical apparatus; a mixing region; a first conduit for carrying a first part of the flow of gaseous fluid from the intake to the mixing region; a second conduit for carrying a second part of the flow of gaseous fluid from the intake to the mixing region; and a heater configured to heat the first part more than the second part, and wherein the detector inlet is configured to combine the first part with the second part in the mixing region.

Abstract: A detector comprising an analytical apparatus for detecting a substance of interest, and a detector inlet. The detector inlet comprises a flow passage for carrying a flow of fluid, the flow passage comprising a sampling volume, and a sampling inlet adapted to collect samples of the fluid from the sampling volume as the fluid flows past the sampling inlet, and to provide the samples to the analytical apparatus, wherein the flow of fluid carries particulates. The detector inlet also comprises a flow director arranged to vary a spatial distribution of the particulates carried by the fluid to increase a relative proportion of the particulates carried past the sampling inlet along the flow passage without entering the sampling volume.

Abstract: A detector comprising an analytical apparatus for detecting a substance of interest, and a detector inlet. The detector inlet comprises a flow passage for carrying a flow of fluid, the flow passage comprising a sampling volume, and a sampling inlet adapted to collect samples of the fluid from the sampling volume as the fluid flows past the sampling inlet, and to provide the samples to the analytical apparatus, wherein the how of fluid carries particulates. The detector inlet also comprises a flow director arranged to vary a spatial distribution of the particulates carried by the fluid to increase a relative proportion of the particulates carried past the sampling inlet along the flow passage without entering the sampling volume.

Abstract: A detector inlet for providing a sample to an analytical apparatus for detecting a substance of interest, the detector inlet comprising a plenum for allowing passage of a flow of a gaseous fluid, the plenum comprising a sampling volume a sampling inlet arranged in the plenum and arranged to collect samples of the gaseous fluid from the sampling volume and to provide the samples to the analytical apparatus, wherein the flow carries particulates and a flow director arranged to create circulatory flow of the gaseous fluid around the plenum encircling the sampling inlet thereby to vary a spatial distribution of the particulates carried by the fluid to increase a relative proportion of the particulates carried past the sampling inlet without entering the sampling volume.

Abstract: An ion mobility spectrometer comprising an ioniser for ionising a sample; a detector separated from the ioniser by a drift chamber along which ions can travel from the ioniser toward the detector; a gate for controlling the passage of ions from the ioniser to the drift chamber; an ion modifier arranged between the ioniser and the detector and comprising a first electrode and a second electrode; and a voltage provider configured to provide a time varying voltage between the first electrode and the second electrode wherein the time varying voltage has a frequency of at least 2.5 MHz.

Abstract: A detector comprising an analytical apparatus for detecting a substance of interest, and a detector inlet. The detector inlet comprises a flow passage for carrying a flow of fluid, the flow passage comprising a sampling volume, and a sampling inlet adapted to collect samples of the fluid from the sampling volume as the fluid flows past the sampling inlet, and to provide the samples to the analytical apparatus, wherein the how of fluid carries particulates. The detector inlet also comprises a flow director arranged to vary a spatial distribution of the particulates carried by the fluid to increase a relative proportion of the particulates carried past the sampling inlet along the flow passage without entering the sampling volume.

Abstract: A detector comprising an analytical apparatus for detecting a substance of interest, and a detector inlet. The detector inlet comprises a flow passage for carrying a flow of fluid, the flow passage comprising a sampling volume, and a sampling inlet adapted to collect samples of the fluid from the sampling volume as the fluid flows past the sampling inlet, and to provide the samples to the analytical apparatus, wherein the flow of fluid carries particulates. The detector inlet also comprises a flow director arranged to vary a spatial distribution of the particulates carried by the fluid to increase a relative proportion of the particulates carried past the sampling inlet along the flow passage without entering the sampling volume.

Abstract: An ion mobility spectrometer comprising an ioniser for ionising a sample; a detector separated from the ioniser by a drift chamber along which ions can travel from the ioniser toward the detector; a gate for controlling the passage of ions from the ioniser to the drift chamber; an ion modifier arranged between the ioniser and the detector and comprising a first electrode and a second electrode; and a voltage provider configured to provide a time varying voltage between the first electrode and the second electrode wherein the time varying voltage has a frequency of at least 2.5 MHz.

Abstract: An ion mobility spectrometer comprising an ionizer for ionizing a sample; a detector separated from the ionizer by a drift chamber along which ions can travel from the ionizer toward the detector; a gate for controlling the passage of ions from the ionizer to the drift chamber; an ion modifier arranged between the ionizer and the detector and comprising a first electrode and a second electrode; and a voltage provider configured to provide a time varying voltage between the first electrode and the second electrode wherein the time varying voltage has a frequency of at least 2.5 MHz.

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: A detector inlet for providing a sample to an analytical apparatus for detecting an aerosol, the detector inlet comprising; an intake for inhaling a flow of gaseous fluid to be sampled by the analytical apparatus;a mixing region;a first conduit for carrying a first part of the flow of gaseous fluid from the intake to the mixing region;a second conduit for carrying a second part of the flow of gaseous fluid from the intake to the mixing region; and a heater configured to heat the first part more than the second part,and wherein the detector inlet is configured to combine the first part with the second part in the mixing region.

Abstract: A detector inlet for providing a sample to an analytical apparatus for detecting a substance of interest, the detector inlet comprising a plenum for allowing passage of a flow of a gaseous fluid, the plenum comprising a sampling volume a sampling inlet arranged in the plenum and arranged to collect samples of the gaseous fluid from the sampling volume and to provide the samples to the analytical apparatus, wherein the flow carries particulates and a flow director arranged to create circulatory flow of the gaseous fluid around the plenum encircling the sampling inlet thereby to vary a spatial distribution of the particulates carried by the fluid to increase a relative proportion of the particulates carried past the sampling inlet without entering the sampling volume.

Abstract: A detector comprising an analytical apparatus for detecting a substance of interest, and a detector inlet. The detector inlet comprises a flow passage for carrying a flow of fluid, the flow passage comprising a sampling volume,and a sampling inlet adapted to collect samples of the fluid from the sampling volume as the fluid flows past the sampling inlet, and to provide the samples to the analytical apparatus, wherein the flow of fluid carries particulates. The detector inlet also comprises a flow director arranged to vary a spatial distribution of the particulates carried by the fluid to increase a relative proportion of the particulates carried past the sampling inlet along the flow passage without entering the sampling volume.

Abstract: Systems and techniques for cleaning a corona discharge point are described. A controller (150) can be operatively coupled to a corona discharge point (108) to control the operation of the corona discharge point (1089. The controller (150) and the corona discharge point (108) can be included with, for example, an ion mobility spectrometry (IMS) system (100). The controller (150) can be used to operate the corona discharge point (108) at an operating voltage for a first time interval, with or without an additional higher pulse voltage, to produce a corona discharge, and to operate the corona discharge point (108) at a cleaning voltage greater than the operating voltage for a second time interval subsequent to the first time interval to produce a corona discharge.

Abstract: An ion mobility spectrometer comprising an ioniser for ionising a sample; a detector separated from the ioniser by a drift chamber along which ions can travel from the ioniser toward the detector; a gate for controlling the passage of ions from the ioniser to the drift chamber; an ion modifier arranged between the ioniser and the detector and comprising a first electrode and a second electrode; and a voltage provider configured to provide a time varying voltage between the first electrode and the second electrode wherein the time varying voltage has a frequency of at least 2.5 MHz.

Abstract: Systems and techniques for cleaning a corona discharge point are described. A controller (150) can be operatively coupled to a corona discharge point (108) to control the operation of the corona discharge point (1089. The controller (150) and the corona discharge point (108) can be included with, for example, an ion mobility spectrometry (IMS) system (100). The controller (150) can be used to operate the corona discharge point (108) at an operating voltage for a first time interval, with or without an additional higher pulse voltage, to produce a corona discharge, and to operate the corona discharge point (108) at a cleaning voltage greater than the operating voltage for a second time interval subsequent to the first time interval to produce a corona discharge.

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.