Abstract: A gas detector (10) that is arranged to sense the concentration levels of target gases oxygen, methane, carbon monoxide, and hydrogen sulphide, within a gas sample from an environment surrounding the detector. The gas detector (10) comprises laser sources (12a-12d) that are arranged to transmit radiation through the gas sample at four target wavelengths that correspond approximately to the optimum absorption wavelengths of each of the target gases and an optical detector (16) that is arranged to sense the intensity of the radiation transmitted through the gas sample at each of the target wavelengths. A control system (22) generates representative concentration level information for the target gases based on the level of absorption of the radiation transmitted.

Abstract: The present invention relates to optical sensor arrangements, especially sensors of the type that can be used in motor vehicles and which can detect hydrogen in a gaseous measured medium.

Abstract: A method and apparatus for measuring target gas concentrations in an atmosphere. The method and apparatus emit in the atmosphere a laser beam tuned to a molecular absorption line of a target gas, receive a reflected signal affected by gas absorption of the target gas in the atmosphere, divide and direct the received signal into a first optical path and a second optical path including in one of the paths a correlation gas cell filled with a predetermined concentration of the target gas, detect transmitted signals through the first optical path and the second optical path, and calculate a target gas concentration by comparing a first signal transmitted through the first optical path to a second signal transmitted through the second optical path.

Abstract: A system for the detection and analysis of at least one volatile substance in breath samples of a subject, including at least one source of infrared radiation adapted to the wavelength range of specific absorption peaks of said substances, a plurality of reflecting surfaces of said radiation adapted for collimation onto at least one detector providing a plurality of electrical output signals corresponding to the transmission of said radiation within wavelength intervals corresponding to said absorption peaks, at least one measuring cell including a mechanical support structure defining the position of said source, reflecting surfaces and detector, adapted to the reception and disposal of said breath sample, and exposing it to said radiation, at least one electronic signal processing unit with capacity to analyse said signals with respect to pre-programmed information concerning infrared absorption spectra of said substances.

Abstract: A method and apparatus for measuring target gas concentrations in an atmosphere. The method and apparatus emit in the atmosphere a laser beam tuned to a molecular absorption line of a target gas, receive a reflected signal affected by gas absorption of the target gas in the atmosphere, divide and direct the received signal into a first optical path and a second optical path including in one of the paths a correlation gas cell filled with a predetermined concentration of the target gas, detect transmitted signals through the first optical path and the second optical path, and calculate a target gas concentration by comparing a first signal transmitted through the first optical path to a second signal transmitted through the second optical path.

Abstract: A gas measuring apparatus includes: an infrared detecting section that receives an infrared ray from a measurement area and outputs infrared spectrum data relating to the infrared ray; a variation detecting section that detects, by using the infrared spectrum data, a variation in intensity of the infrared ray, which is caused in the infrared ray that radiates from the measurement area and which is caused by a measuring object gas in the measurement area; a converting section that converts the infrared spectrum data to radiance temperature spectrum data which represent wavelengths in an infrared region and radiance temperatures at each wavelength; a background temperature detecting section that detects, as background temperature of the measuring object gas, a maximum radiance temperature from among radiance temperatures represented by the radiance temperature spectrum data; a gas temperature detecting section that detects the temperature of the measuring object gas by using a radiance temperature in a waveleng

Abstract: There is described a method for measuring a concentration of a gas component in a measuring gas, wherein the light of a wavelength tunable light source is passed along a single optical path through a measuring volume containing the measuring gas and a reference cell containing a reference gas to a detector. The reference cell is selected to contain a selected isotope of the gas component to be measured in a known abundance ratio higher than the known natural-abundance isotope ratio of the gas component in the measuring volume; the light source is tuned to sweep the wavelength of the light over the absorption lines of the selected isotope and the remaining gas component; and the concentration of the gas component in the measuring volume is calculated from the ratio of the detector signals at the peaks of the absorption lines, based on Lambert's law and taking into account the known abundance isotope ratios.

Abstract: A spectroscopic gas sensor is disclosed, which has at least: an IR radiation source for emitting IR radiation, a measuring volume to be completely or partially filled with an air supply volume, in particular an exhaled air, a detector unit having at least one, preferably two detector elements for detecting the IR radiation passing through the measuring volume in at least one first wavelength range and outputting measuring signals, and an analyzer unit for recording the measuring signals and ascertaining a concentration of a measured substance in the air supply volume. A first detector element measures IR radiation in a wavelength range of an absorption band of the measured substance, and the analyzer unit ascertains a concentration of the measured substance in the air supply volume from the ascertained concentrations of the measured substance and a further component in the measuring volume.

Abstract: NDIR gas sensing methodology is advanced which renders the output of an NDIR gas sensor, when implemented with this new methodology, to remain stable or drift-free over time. Furthermore, the output of such a sensor will also be independent of the temperature of an environ wherein the sensor is in physical contact. This method utilizes the same narrow band-pass spectral filter for the detection of the gas of interest for both the signal and the reference channels. By so doing, the two channels always receive radiation of the same spectral content from the infrared source of the sensor convoluted with that from any external elements exposed to the sensor. While the same sample chamber through which the gas of interest to be detected flows is shared by the two channels, the detector package for the reference channel is hermetically sealed with 100% of the gas to be detected instead of 100% N2 as for the signal detector.

Abstract: The invention relates to a system and method for detecting one or more gases or gas mixtures and/or for measuring the concentration of one or more gases or gas mixtures, said system comprising at least a light source, a sample space, a reference chamber, and a measuring chamber. The measuring chamber is supplied with a gas to be detected or measured. In addition, the measuring chamber is provided with a pressure sensor for detecting a photoacoustic signal generated in the measuring chamber. The pressure sensor comprises either a door, whose movement is measured without contact, or a sensor, whose movement is measured optically.

Abstract: An apparatus and method for quantifying ketone or alydehyde concentrations of gas. The invention includes passing a gas sample through a reactor and an optical cell and determining a concentration of a gaseous reaction product. Using the concentration of the gaseous reaction product and a predetermined reaction conversion efficiency, a ketone or aldehyde concentration is calculated. This invention can be used for diabetes screening, diabetes maintenance, identification and quantification of ketosis, explosives detection and formaldehyde detection.

Abstract: A method of calibrating an absorption spectroscopy measurement wherein the calibration method includes projecting laser light through a sample of a first quantity of a gas of interest and a second irrelevant quantity of a spectroscopically identical or similar gas (10). The first and second spectroscopic absorptions of the laser light are measured over specific first and second absorption lines. A functional relationship is determined between the first and second measured spectroscopic absorptions and two unknown variables. The function relationships may then be simultaneously solved to determine one or both unknown variables and thereby obtain a measurement relating to the first quantity of the gas of interest, calibrated for the second irrelevant quantity of gas.

Abstract: Provided are a gas sensing apparatus and a gas sensing method using the apparatus. The gas sensing apparatus includes a detection chamber, a light source, a light sensor, a gas source, and a controller. The light source is disposed at one end of the detection chamber, and a light sensor is disposed at the other end of the detection chamber. The gas source provides gas to the detection chamber. The controller controls the light source and the light sensor. The light source includes a laser supplying laser light, and a light scanner reflecting and scanning the laser light in the detection chamber. The controller includes a phase sensitive detector electrically connected to the light sensor.

Abstract: A gas detector (10) that is arranged to sense the concentration levels of target gases oxygen, methane, carbon monox-ide, and hydrogen sulphide, within a gas sample from an environment surrounding the detector. The gas detector (10) comprises laser sources (12a-12d) that are arranged to transmit radiation through the gas sample at four target wavelengths that correspond approximately to the optimum absorption wavelengths of each of the target gases and an optical detector (16) that is arranged to sense the intensity of the radiation transmitted through the gas sample at each of the target wavelengths. A control system (22) generates representative concentration level information for the target gases based on the level of absorption of the radiation transmitted.

Abstract: A mechanism of a monitoring unit of an electric rotating machinery covered in a housing that intercepts photoelectron transmission, the mechanism has: a monitoring window penetrating a part of the housing and configured to allow passage of photoelectrons and not to allow passage of gas; a camera arranged outside the monitoring window and configured to receive radiated photoelectron generated in the housing and passing through the monitoring window and to generate image data from the radiated photoelectron; and a computing unit configured to process the image data. The computing unit has reference image data storage means for storing image data resulting from blackbody radiation occurring in a reference state in the housing, as reference image data, and temperature calculating means for comparing the image data with the reference image data, thereby to calculate the temperature in the housing.

Abstract: An optical sensor is configured to determine an amount of at least one material in a sample without interference from any of the material of interest present in an ambient environment in which the optical sensing is effected. The optical sensor may include a compensation detector positioned a different distance apart from a source of monitoring radiation than the distance that a primary, measurement detector is positioned from the source. Alternatively, the optical sensor may include an optically transparent material that consumes space within the sensor and, thus, eliminates ambient amounts of a material of interest from at least a portion of an optical pathway through the sensor. A calibration element transmits calibration radiation to one or more detectors of an optical sensor to facilitate correction of any changes in the manner in which the one or more detectors sense radiation. Optical sensing methods are also disclosed, as are calibration methods.

Abstract: An apparatus for monitoring the exhaust of an engine includes a flow-through chamber for receiving exhaust, a source of electromagnetic radiation and a detector. The source provides electromagnetic radiation in a range comprising the infrared, visible and ultraviolet wavelengths. The source and a detector are arranged so that radiation passing through the chamber is incident on the detector. An electronic circuit is connected to the detector to provide a signal indicative of the attenuation of the radiation by particles in the exhaust in the chamber. The detector provides respective measures of radiation which it receives for at least two different wavelengths of the radiation, and the electronic circuit provides corresponding electrical signals indicating the attenuation of the two different wavelengths by particles within the exhaust in the chamber. The wavelengths are selected to be those for which the attenuation caused by nitrogen dioxide in the exhaust is substantially the same.

Abstract: Low concentrations of water vapor within a background of one or more olefin gases may be detected and quantified using a differential absorption spectrometer. A dehydrated sample of the gas is used as a background sample whose absorption spectrum allows elimination of absorption features not due to water vapor in the gas. Absorption spectra may recorded using tunable diode lasers as the light source. These lasers may have a wavelength bandwidth that is narrower than the water vapor absorption feature used for the differential absorption spectral analysis.

Abstract: A concentration of ethanol is detected without using any light source such as a lamp by utilizing a face of a human being as a light source.

Abstract: A gas concentration measuring apparatus utilizing a gas correlation method capable of measuring concentrations of a plurality of analyte gases simultaneously and at high sensitivity uses an infrared light source (2) such as an infrared semiconductor diode or a quantum cascade semiconductor laser to increase the intensity of collimated infrared light (5) and to lessen infrared light unnecessary for measurement, thereby improving the S/N ratio while achieving a rise in sensitivity. A plurality of analyte gases are simultaneously measured by means of a gas correlation filter comprising a reference gas cell (6a) filled with all of the analyte gases and a plurality of probe gas cells (6b) each individual of which is filled with all such analyte gases other than one of the analyte gases which is of its particular interest.

Abstract: A combined gas sensor device allowing the measuring of the concentration of a gas by tunable diode laser spectrometry as well as by resonant photo-acoustics within one housing. A laser beam used for laser spectrometry is sent across the openings of a measuring cell usually used for resonant photo-acoustic determination. Thus, both measuring principles use the same gas sensing module with a minimum of space consumption, so that the device can be produced with minimum dimensions. Further, a common opto-electronics and electronics platform can be used which reduces the overall costs of such a combined gas sensor.

Abstract: An optical cavity for a Non-Dispersive Infrared gas sensor has invented comprising two oppositely arranged parabolic mirrors having common focus located on the common optical axis of the parabolic mirrors, and a plane mirror arranged along the optical axis between the vertex of each of the parabolic mirrors. The NDIR gas sensor has an extended optical path to increase precision and accuracy in the measurement, and substantially increased ventilation opening size to facilitate in and out of the target gas through the optical cavity thereby decreasing the response time required for measuring the gas concentration. The sensors based on the principal of Non-Dispersive Infrared Detection is used the light-absorbing characteristic of gases to measure the amount of light absorption that occur at the specific wavelength absorbed by a target gas and calculate the target gas concentration.

Abstract: A laser processing machine includes a measuring cell into which gas to be analyzed can flow, a means for decoupling diagnostic radiation from the laser radiation provided for material processing of a workpiece, and a sound detector for detecting the photo-acoustical effect produced in the measuring cell due to absorption of the diagnostic radiation by gas in the cell.

Abstract: A method for improving optical measurement of gas concentration includes steps for directing narrow band light to the gas to be measured and measuring the attenuation of the light in the gas, modulating the center wavelength of the light source around or over a first predetermined absorption maximum (absorption line) of the measured gas and aside of it, measuring the attenuation of the light in the gas as a function of the center wavelength of the light, and determining the gas concentration based on the measurement. The center wavelength of the light is varied such that the center wavelength is adapted to coincide with at least one other absorption maximum (peak) with different absorption properties of the gas to be measured, and correspondingly the attenuation of the other absorption maximum or maxima is measured as a function of the center wavelength of the light.

Abstract: Disclosed is a method and apparatus for detecting the type of anesthetic gas. The method comprises the steps of: generating a light with a plurality of wavelengths, the light being able to be separated to a plurality of light beams whose central frequencies correspond to the plurality of wavelengths; passing said light through a gas chamber, wherein, the gas chamber being filled with said anesthetic gas, said anesthetic gas having absorption characteristic with respect to said plurality of light beams; detecting the light intensity of the attenuated light beams transmitted from the gas chamber respectively, to obtain the relative absorption characteristic of said attenuated light beams, which attenuated light beams having been absorbed by said anesthetic gas; and determining the type of said anesthetic gas based on the relative absorption characteristic between said attenuated light beams.

Abstract: The invention relates to a microstructured sensor, having at least one measurement chip in which there is formed a first measurement area having a first measurement structure and a second measurement area having a second measurement structure, the measurement areas being offset to one another in a lateral direction, one cap chip that is fastened in vacuum-tight fashion to the measurement chip in a connecting area, one intermediate space, formed between the measurement chip and the cap chip, that is sealed outwardly by the connecting area and in which the measurement areas are situated, and at least one contact area, formed on the measurement chip, and left exposed by the cap chip, for the contacting of the measurement chip. The sensor can be in particular a gas sensor for measuring a gas concentration, or an acceleration sensor.

Abstract: A gas measurement system of this invention includes a housing adapted to be mounted on an airway adapter, and a luminescence quenching gas measurement assembly disposed in the housing. The luminescence quenching gas measurement assembly includes a source disposed in a first plane, and at least one detector also disposed in the first plane.

Abstract: A long range optical sensor and system for detecting the flame of forest fires or other fires while rejecting false alarms due to solar radiation is described. The sensor utilizes a collector optic that collects energy from a wide field of view and concentrates the energy onto a detector. The collector may be a non-imaging collector and may match to a non-planar sensor. In one embodiment the sensor may be arrayed to achieve larger area coverage. In another, the sensor system may be scanned to increase the encompassed viewing area. Larger areas may be covered by RF radio links or networks interconnecting multiple arrayed sensor modules. UVC reflective coatings may include enhanced aluminum with silicon dioxide, silicon monoxide, or magnesium fluoride, or high phosphorous nickel phosphorous. In one embodiment a UVC sensitive Geiger Mueller tube may be coupled to a non-imaging spherical reflective collector. A catadioptric UVC/infra-red flame sensor is disclosed. Refractive or reflective designs are considered.

Abstract: A gas sensor comprises a cavity for containing a gas, means for generating radiation which is transmitted through the cavity and includes one or more wavelengths which is absorbed in use by a gas to be detected; and a detector for detecting radiation which has passed through the cavity. The walls of the cavity are sufficiently reflective to the radiation that the cavity is substantially uniformally illuminated with the radiation.

Abstract: A method and apparatus architecture for detecting gases, particularly hazardous gases which should be detected in miniscule amounts. High sensitivity detection of chemical warfare agents (CWAs) is set forth with very low probability of false positives (PFP) by the use of an innovative laser-photoacoustic spectrometer (L-PAS). Detection of diisopropyl methylphosphonate (DIMP), a decomposition product of Sarin and a relatively harmless surrogate for the nerve gases, is made in the presence of other gases that are expected to be interferences in an urban setting. Detection sensitivity for DIMP in the presence of these interferences of better than 0.45 ppb, which satisfies current homeland and military security requirements is shown as well as the first analysis of optical techniques for the detection of chemical warfare agents (CWAs) and toxic industrial chemicals (TICs) in real world conditions.

Abstract: A terahertz spectroscopy system includes a source of terahertz radiation, a detector of terahertz radiation, a source of sample gas, and a sample cell that can be cooled to cryogenic temperatures. The sample cell may be configured to receive the sample gas, received terahertz radiation from the source of terahertz radiation, provide the terahertz radiation to the detector after the terahertz radiation has passed through the sample gas, and facilitate cryogenic cooling thereof. The sample cell may be cryogenically cooled to freeze the sample gas and subsequently warmed either continuously or in steps in temperature so that individual components or groups of components of the sample gas may evaporate and thus have absorption spectra formed therefor. Enhanced resolution of absorption spectra is provided when a gas sample contains a large number of components of different gases.

Abstract: A gas sensor for sensing the presence of a gas includes an IR source, a microphone, a reference gas substantially similar to the gas to be detected, a reference body defining a reference chamber therein, the reference chamber having a pressure port coupled to the microphone, and a broad-band optical window through which at least IR wavelengths corresponding to absorption peaks of the predetermined gas may pass. The window is disposed between the IR source and reference chamber. The reference gas is contained within the reference chamber between the optical window and the microphone. The sensor can be included in a hand-held gas detection instrument having power supply, an outer shell, a circuit board assembly including sensor circuitry, a suction pump, actuation controls and status indicators. A probe defining a lumen therethrough supplies the sample gas.

Abstract: A unique optical cavity for NDIR gas sensor module and test results for the CO2 concentration from 100 ppm to 2,000 ppm are disclosed. The proposed sensor module shows the maximum peak voltage at 500 ms pulse duration, however, it has a maximum fractional voltage changes at 200 ms pulse duration with 18,000 times amplification gain. From 100 ppm to 2,000 ppm, the voltage difference of sensor module (V) is 200 mV at 200 ms pulse duration and 3 sec. turn-off time.

Abstract: A multi-pass gas cell that operates with reflected radiation pass through a gas, the reflected radiation transmitted and received by first and second fiber optic ports that are subject to an alignment adjustment, and a mirrored viewing window having a inner reflective surface exposed to an interior of the elongated cell body for reflecting the radiation within the cell body, an outer viewing surface, and a transmittance characteristic that permits a portion of the radiation to pass through the mirrored window, from the inner reflective surface to the outer viewing surface, as a visual indicator of the alignment condition of the reflected radiation relative to the first and second fiber-optic ports.

Abstract: A gas sensor comprises a body on which is mounted an optical source and a detector means sensitive to light from the source. The body further comprises a channel arranged to admit gas, the channel comprising an elongated groove having reflective surfaces defining a folded optical path for light from the source. The groove is arranged as a serpentine shape or spiral shape so that light from the source to detector travels around the groove being internally reflected within the shape.

Abstract: The concentration of a gas species is detected by using a single beam NDIR gas sensor in which an infrared source element is driven at two different temperatures, a feed back loop senses an operation voltage of the source, a differential gain amplifier creates a high cycle amplified output during a high cycle and a low cycle amplified output during a low cycle while a controller synchronizes the source driver so that a signal processor can determine the gas concentration through use of the high cycle amplified output and the low cycle amplified output. The infrared source can be a non-genuine blackbody source such as an incandescent miniature light bulb when the sample chamber is a thermally insulated aluminum tube that is maintained at a preselected temperature greater than ambient so that the glass envelope of the bulb is maintained at an equilibrium temperature (such as approximately 30 degrees Celsius plus or minus two degrees Celsius) during its low cycle operation state.

Abstract: An improved elemental mercury analyzer utilizes a fluorescence assembly in combination with a fluorescence quenching reduction mechanism to detect the concentration of elemental mercury within an emission gas sample, via fluorescence of the mercury within the gas sample, while minimizing fluorescence quenching of the gas sample. In one arrangement, the analyzer contains the emission gas sample under a vacuum or negative pressure while detecting fluorescence of the elemental mercury within the emission gas sample. By performing fluorescence detection of the emission gas sample at reduced pressure relative to the pressure of the as-sampled emission gas, the analyzer reduces the number of particle collisions within the emission gas sample over a certain period of time. Such collisional deactivation, and/or the addition of oxygen depleted gas such as nitrogen to the gas sample, reduces fluorescence quenching of the emission gas sample, improving accuracy of detection of mercury.

Abstract: A spectrometer energizes a solid state oscillator to generate a submillimeter wave and to sweep a predetermined band of frequency. The submillimeter wave is introduced into a sample cell that contains a gas, and frequency markers are electrically generated during the sweep. Outputs of a solid state detector disposed in the sample cell are read and recorded as a function of time and with the frequency markers. The recorded outputs of the solid state detector are converted into a function of frequency using the recorded frequency markers.

Abstract: A system and method are disclosed for the detection of water vapor in a natural gas background. The system includes a light source operating in a wavelength range such as, 1.877-1.901 ?m, 2.711-2.786 ?m, or 920-960 nm, passes through the natural gas to be detected by a detector. In one embodiment, the light source is a tunable diode laser and the moisture level is determined by harmonic spectroscopy. In other embodiments, a VCSEL laser is utilized.

Abstract: There are provided an infrared gas analyzer of a simple configuration, capable of taking measurements with high precision when using an infrared light source excellent in thermal responsiveness, and capable of ON/OFF operations at high speed, and an infrared gas analysis method using the same.

Abstract: The invention relates to a mobile remote detection device for accumulations of methane, comprising an emitter device having a light source in order to generate light, the wavelength of said light source being tuned with the spectral signature of methane, whereby the light can be directed onto a measuring field. The detection device also comprises a detector device for detecting backscattered light, and an evaluation device. The aim of the invention is to improve the remote detection device in such a manner that it has a high degree of measuring sensitivity with a compact and stable structure. According to the invention, the light source generates light with a wavelength at which methane is absorbed, wherein the wavelength lies between 3200 nm and 3300 nm, and the light source has an optical parametric oscillator with injection seeding, the oscillator being associated with a pump laser.

Abstract: A sample cell, which is a component of a gas monitoring system, includes a sample cell body and a sample cell core installed therewith. The sample cell is coupled to a sampling tube that communicates with an airway of a patient. Gas from the sampling tube passes through the sample cell such that the flow profile remains substantially undisturbed. Within the sample cell, at least one optical aperture permits radiation to be emitted, pass through the gas in the sample cell core, and detected. In this manner, measurements of the partial pressure or concentration of a gas of interest are determined.

Abstract: An infrared sensor for gas metering appliances consisting of a metering chamber with an infrared source and an infrared sensor. The metering chamber is connected to the atmosphere via an anti-dust and anti-damp filter. The metering chamber is arranged in a protective housing having gas inlets and outlets. Connection to the metering chamber via a gas exchanger orifice and an anti-dust and anti-damp filter is not of a pressure-proof design based on normal pressure conditions. The infrared source and the infrared detector are integrated in the wall of the metering chamber and held therein. The infrared source is a lamp. The infrared source and infrared detector have a fail-safe power supply.

Abstract: A gas sensor module for the spectroscopic measurement of at least one gas concentration, including at least: a spectroscopic gas sensor having a sensor chip which has a micropatterned measuring structure, and having an IR-transparent cap chip covering the measuring structure; a premolded package having a package bottom and a package edge to which a cover having a screen opening provided above the measuring structure is attached; a filter chip provided between the cover and the cap chip; and a lead frame which is partially injected into the premolded package and has multiple leads that include connecting pins for contacting a substrate and contact pads which contact the contact pads of the gas sensor, the connecting pins being bent upward from the package edge. The gas sensor module is mountable by its connecting pins to a substrate in such a way that the measuring structure having the filter chip is positioned directly opposite a substrate opening.

Abstract: A method for detecting the concentration of one or more gas species by using infrared radiation emitted from one or more sources into a sample cell which is a hollow waveguide with multiple bends collectively greater than 180 degrees in three dimensions, the infrared radiation being quasi-focused into a beam with an angle of incidence between greater than approximately 0° and approximately 10° relative to a longitudinal axis of a first linear segment of the sample cell proximate the source, then detecting two or more signals in which one of the signals is used to compensate for water vapor. The methods can detect gas concentrations down to 1 ppm or less.

Abstract: A system for identifying a gas sample includes a canister, a docking station, a thermal desorption device, and a spectrometer. The canister includes a sorbent and a valve. The docking station is configured to removably engage the canister. When the canister is engaged with the docking station, the canister is capable of fluid communication with a gas cell via the valve.

Abstract: A gas species monitoring system includes a laser system, where the laser system includes a multisection DBR laser, and a plurality of measurement points disposed at different locations within the system. The laser system is configured to selectively deliver a laser beam from the multisection DBR laser to each measurement point within the system to determine a concentration of at least one gas species at each measurement point. A chemical detection grid is aligned with the ITU-GRID to facilitate use of a multisection DRB laser that operates within one or more of the defined bands of the ITU-GRID.

Abstract: A fire detector and method for generating an alarm signal in response to a fire uses an NDIR CO2 sensor to generate a detector signal based upon a 15? absorption band of CO2 and generates an alarm signal when a signal processor receives the detector signal and a preselected criterion is met that is indicative of the onset of a fire based upon an analysis of the detector signal using a detection algorithm that relies upon a trending pattern of the detector signal such as recognizing a substantial drop in the detector signal strength. The NDIR CO2 sensor can also generate a reference detector signal based upon a 9.0? neutral band with a FWHM=0.5? while the signal processor utilizes a detection algorithm that is based upon a synchronized output signal representative of CO2 concentration to generate an alarm signal when a preselected criterion indicative of the onset of a fire is met.

Abstract: The invention relates to a photoacoustic detector, comprising at least a first chamber (V0) suppliable with a gas to be analyzed, a window for letting modulated and/or pulsed infrared radiation and/or light in the first chamber (V0), a second chamber (V), which constitutes a measuring space with a volume V and which is in communication with the first chamber by way of an aperture provided in a wall of the first chamber, at least one sensor, which is arranged in the wall aperture of the first chamber and arranged to be movable in response to pressure variations produced in the first chamber by absorbed infrared radiation and/or light, and means for measuring the sensor movement. The means for measuring the sensor movement include at least one or more light sources for illuminating the sensor or a part thereof and one or more multi-detector detectors for the reception of light reflected from the sensor and for measuring the sensor movement as optical angular and/or translatory measurement.

Abstract: An unmanned integrated RES 12 integrates all of its components except the reflector 22 into a single console 30 that is positioned at the side of a road and has a CPU 36 that controls calibration, verification and data gathering. The RES's source 32 and receiver 34 are preferably stacked one on top of the other such that the IR beam 24 traverses a low and high path as it crosses the road 14. This allows the RES to detect both low and high ground clearance vehicles. To maintain the vehicle processing and identification throughput, the speed sensor 54 and ALPR 48,50 detect the passing vehicles at steep angles, approximately 20 to 35 degrees. In a preferred system, a manned control center 16 communicates with a large number of the unmanned integrated RES to download emissions data, perform remote diagnostics, and, if necessary, dispatch a technician to perform maintenance on a particular RES.