Abstract: An optical gas sensor has a compact design and without movable optical elements, with at least one radiation source (8), at least one measuring detector (9, 12) and a reference detector (11). The reflecting measuring cuvette is designed as an annular space (1) between a first, inner cylinder section (6) and a second, outer cylinder section (2) that is concentric thereto. The annular space (1) is limited by a cover element (5) and a bottom element (7) arranged at a spaced location therefrom in the direction of the longitudinal axis. The cover element (5) is permeable to the measuring gas. The bottom element (7) accommodates the radiation source (8).

Abstract: An isotope gas measuring apparatus for measuring concentrations of components in a sample gas includes two sample cells through which the sample gas passes; a control cell filled with a gas having no absorbance at a wavelength of infrared light to be measured; a light source irradiating infrared light to the sample cells and the control cell; an optical coupler for coupling light permeated from the sample cells and the control cell; a first interference filter disposed between one sample cell and the optical coupler; a second interference filter disposed between the other sample cell and the optical coupler; and an optical detector for detecting infrared light from the optical coupler. The apparatus can minimize an influence of drift, and have a simple structure.

Abstract: A system for detecting the presence of nerve agents includes a support platform such as a satellite or an aircraft located above and spaced from the surface of the earth. An imaging spectrometer is disposed on the support platform and absorbs radiation emitted from a selected portion of the earth. The imaging spectrometer operates in a plurality of sub-bands in a spectral transmission band from 8 to 14 microns, and measures the spectral intensity present in each sub-band. The spectral intensity in each of the sub-bands is compared to a reference intensity and indicates the presence of the nerve agent when the spectral intensity in a particular sub-band differs from the reference intensity by a preselected amount.

Abstract: A method and apparatus for monitoring the flue gases of a furnace combustion process is disclosed. A by-pass circuit that communicates a sample of flue gases to be monitored from a furnace, through a measurement chamber and back to the furnace or furnace exhaust duct is provided. The by-pass circuit has a gas sampling probe with a fume inlet opening, the probe being positioned for withdrawing the sample to be monitored and transmitting it through the by-pass circuit. A measurement device is positioned in the measurement chamber and comprises an in situ optical device which provides real-time measurement of targeted flue gas species concentrations.

Abstract: The present invention provides methods and apparatus for flexible and reproducible control ofquantum cascade laser frequency scans having short (nanosecond) pulse excitations. In accordance with a preferred embodiment of the invention, a method of digital frequency control for pulsed quantum cascade lasers includes digitally synthesizing a sub-threshold current, converting the sub-threshold current to analog form, and generating laser pulses. Preferably, the sub-threshold current is synchronized to the laser pulses.

Abstract: An optical gas-measuring system and process identifies especially infrared-active individual gases over a measuring path of about 100 m and to determine their concentration averaged over the measuring path swept. The laser source (11) emits a divergent ray beam, from which both the measuring beam and the reference beam are formed after a single-time reflection of the emitted ray beam. A first radiation reflector (14) is designed in the form of a first hollow mirror for the reflection of a first part of the ray beam emitted from the laser source (11) as a measuring beam into the open optical measuring path. A second radiation reflector (16) is designed in the form of a second hollow mirror for the reflection of a second part of the ray beam emitted from the laser source (11) as a reference beam into a reference gas cuvette (17) containing the reference gas sample for the gas to be measured.

Abstract: Method of controlling an evaporative light scattering detector comprising:

Abstract: A method for detecting and measuring volatile components in expired gas by sampling the expired gas containing the volatile components; passing infrared radiation from an interferometer through the sample; detecting infrared radiation transmitted from the sample to produce a signal characteristic for the volatile components in the sample; and processing the signal and a set of single component reference library spectra of pure molecular gases in order to detect and calculate the amount of the volatile components in the blood of an individual expiring the gas, including the use of a low resolution FT-IR spectrometer in the detecting and processing.

Abstract: A photometric device and method for determining the gross calorific value of a test gas, especially natural gas having a radiation source that produces a measuring beam and a modulation unit to modulate the measuring beam. A test cell with test gas and a receiver for the beam are arranged successively in the path of the measuring beam. The measuring signals of the receiver are supplied to an evaluation unit that includes at least one signal amplifier for the amplification of the signals. The signal amplifier is provided with adjustment devices to adjust the signal amplifier according the spectral properties of the measuring beam. The gross calorific value of the gas is indicated by the sum of the amplified measuring signals produced in a computing machine.

Abstract: A gas detection system and method are provided for determining the type of gas present and the concentration of the gas in terms of a percentage of a specific level of the gas. This percentage level may be in terms of a lower explosive limit level of a combustible gas. The system generally includes a testing chamber, a detection channel apparatus, a memory for storing a plurality of gas signature tables, and a programmed controller for determining the identity and concentration level of a gas. The system and method further provide for the accurate determination of gas concentration level at very high and low concentration levels by weighted average computation.

Abstract: An optical system for a gas component analysis includes an emitter for emitting first light beam having a first spectrum, a second emitter for emitting a second light beam at a second spectrum, a first receiver for receiving the first light beam, and a second receiver for receiving the second light beam.

Abstract: A robust, compact spectrometer apparatus for determining respective concentrations or partial pressures of multiple gases in a gas sample with single as well as multiple and even overlapping, absorption or emission spectra that span a wide spectral range.

Abstract: An apparatus for detecting a gas having distinct infrared radiation absorption characteristics. The apparatus includes a spectral source/bolometer for conducting an electrical current and for producing an infrared radiation. The source/bolometer is disposed along an axis and has a temperature and a characteristic resistance, and the characteristic resistance is a predetermined function of the temperature. A return reflector is disposed along the axis beyond the gas such that at least a portion of the infrared radiation passing through the gas is reflected back through the gas to the source/bolometer. The apparatus also includes a driver/detector for driving a current through the source/bolometer, for determining the characteristic resistance, and for detecting the gas from a variation of the characteristic resistance.

Abstract: Very generally, the gas analyzer of the invention includes a source of infrared energy, a sample cell for containing an analyte gas mixture positioned in the path of infrared energy, and a monochrometer including a movable diffraction grating for producing a beam of infrared energy wherein the constituent wavelengths are spetrally separated. The device also includes a wide band interference filter for transmitting a predetermined wavelength band spanning the characteristic absorption wavelength of each of a plurality of constituent gases in the analyte gas mixture. A detector positioned to receive radiation passing through the filter produces an electrical response related to the infrared energy impinging thereon. The monochrometer includes provision for moving the diffraction grating to sequentially cause infrared energy of different wavelengths to impinge upon the detector, and for intermittently causing infrared energy directed toward the detector from the source to be blocked by the interference filter.

Abstract: The invention relates to a method for identification and partial-pressure determination of two gases in an unknown anesthesia gas mixture comprising n possible gases by measuring the infrared optical radiation, transmitted through the gas mixture, that passes through m filters having different transmission wavelength ranges, in which n is a number greater than 2 and m is a number less than n. A disadvantage of the method known until now is that for the identification and partial-pressure determination, at least as many filters as there are possible gases in the unknown gas mixture are always required. The method of the invention evaluates the exit intensities, measured after passage through the filters, of the infrared optical radiation transmitted through the unknown gas mixture in such a way that with three filters, for instance, two gases in an unknown gas mixture comprising five possible gases can be identified, and their partial pressures can be determined.

Abstract: A multi-component analyzing apparatus for measuring a concentration ratio of gas components of fron gas is provided, while the fron gas is constituted by several sorts of single gas components of fron gas, and the fron gas is employed as a measuring subject sample made by mixing a plurality of measuring subject components with each other, whose sort and quantity are limited.

Abstract: This specification discloses a method and apparatus for the mobile and remote detection of a gas, such as methane, in the atmosphere. The apparatus includes a TDL based Light Detection and Ranging (LIDAR) driven at carrier frequency lying within the absorption line of the gas. The apparatus also drives the TDL with a modulation frequency to generate upper and lower sidebands in the output of the TDL and with a low ramp frequency to sweep the output of the TDL across twice the width of the pressure-broadened absorption line of the gas, preferably the first overtone absorption line in the case of methane detection. Suitable power for remote detection through use of the TDL is provided by a master oscillator/fiber amplifier transmitter has no moving or adjustable parts at all. An all-solid-state monolithic and integrated amplifier is achieved, which leads to a compact and virtually maintenance-free LIDAR system.

Abstract: The invention relates to an arrangement in an apparatus for analyzing, on the basis of radiation absorption properties, one or more gas component included in a gaseous medium from an origin, like exhaled air from a person. The apparatus comprises a radiation source (10); a measuring chamber (8) provided with radiation transmissive windows (7a, 7b) for receiving a gas mixture (6) from at least the gaseous medium (G1); a first detector (1), which receives the radiation passed through the gas mixture; and between the radiation source and the detector a first optical interference filter (3), which has a first radiation transmission wavelength band and which is tiltable (P) relative to the passing radiation (R) beam.

Abstract: Components of sampled gases are analyzed by a Fourier transform infrared spectrophotometer 28. It is determined whether or not the analyzed gases include at least one kind of specific gases equal to or more than a predetermined quantity. In a case where mixed gases include at least one kind of the specific gases equal to or more than the predetermined quantity, a controller 30 supplies an operation display monitor 31 with a signal indicating leakage of the kind of the specific gases. Hence, it is possible to realize detection by kind of the gases with high accuracy irrespective of the kind of leaked gas.

Abstract: Methods are disclosed for determining the monotonic functional relationship between (A) the integrated absorbance of spectral energy within a spectral region of interest of an analyte (i) that decomposes during the time experimental spectral data for determining the relationship are being obtained, or (ii) whose spectral data are pressure sensitive at pressures below a given pressure, or (iii) that decomposes during the time the spectral data are being obtained and whose spectral data are pressure sensitive and (B) the concentration of the analyte before decomposition commences. Methods are also disclosed for using the monotonic functional relationship to determine the concentration of the analyte in an unknown from the integrated absorbance of spectral energy within the spectral region of interest for the unknown.

Abstract: The present invention provides a laser-based method and apparatus that uses absorption spectroscopy to detect the mole fraction of CO2 in a high temperature gas stream. In a preferred embodiment, a distributed feedback based diode laser sensor operating at a wavelength near 1996.89 nm (5007.787 cm−1) interrogates the R(50) transition of the &ngr;1+2&ngr;2+&ngr;3 CO2 absorption band in the near infrared. This transition is specifically chosen based on its superior linestrength and substantial isolation from interfering absorption by high-temperature H2O, CO, NH3, N2O, NO, and other species commonly present in combustion or other high-temperature gas flows.

Abstract: An NDIR sensor includes a cylindrical metallic tube, a printed circuit board platform that fits into one end of the tube, a diffusion filter that fits into the opposite end of the tube, and an optical system. The optical system includes an infrared source on the platform, a mirror on the inner wall of the tube so as to reflect and focus the infrared light from the infrared source, and a detector assembly that receives the infrared light after reflection. The gas sensor may further include a partition between the infrared source and the detector assembly, a removable filter on the diffusion filter, connecting pins attached to the platform, and a sealing layer formed under the platform. The detector assembly includes a signal detector and a reference detector. A first and second bandpass filters are respectively formed on the signal and reference detectors.

Abstract: An isotope gas measuring apparatus for measuring concentrations of components in a sample gas includes two sample cells through which the sample gas passes; a control cell filled with a gas having no absorbance at a wavelength of infrared light to be measured; a light source irradiating infrared light to the sample cells and the control cell; an optical coupler for coupling light permeated from the sample cells and the control cell; a first interference filter disposed between one sample cell and the optical coupler; a second interference filter disposed between the other sample cell and the optical coupler; and an optical detector for detecting infrared light from the optical coupler. The apparatus can minimize an influence of drift, and have a simple structure.

Abstract: A test gas sample containing carbon dioxide 13CO2 as a component gas is introduced into a cell, then the absorbance of light transmitted therethrough at a wavelength suitable for the component gas 13CO2 is determined, and the concentration of the component gas is determined on the basis of a calibration curve prepared through measurement on test gas samples each containing the component gas in a known concentration. Further, the concentration of water vapor contained in the test gas sample is measured, and the concentration of the component gas in the test gas sample is corrected in accordance with the measured water vapor concentration on the basis of a correction curve prepared through measurement on the test gas samples each containing water vapor in a known concentration (FIG. 4). With the spectrometry, the concentration ratio of the component gas can precisely be determined and corrected by measuring the moisture content in the test gas sample.

Abstract: A spectroscopic IR and UV-vis absorption remote exhaust emission monitoring system and sensing instrument for non-invasive, multicomponent analysis of the exhaust plume emitted by in-use vehicles. The concentration of CO, CO2, HC, NO, N2O, C2H2, NH3, SO2, Aromatic hydrocarbons, aldehydes, HONO, NO2, and dust, among others and in any combination there-of, in such a mixture can be determined in real-time, or via post-processing of stored spectral data. The sensor employs an IR and a UV-vis sources, and the physically offset, collimated beams traverse the probed air column, typically a roadway, a plurality of times, before returning to the instrument. Although the IR and UV-vis beams converge at the optics opposite the instrument, they are not coaxial and, thus, do not require an optical device (i.e., dichroic beam splitter) to separate them. The separate IR and UV-vis beams are focused on the slits of rapid spectrometers, where they are analyzed to yield wavelength-resolved spectra (i.e.

Abstract: A test gas sample containing carbon dioxide 13CO2 as a component gas is introduced into a cell, then the absorbance of light transmitted therethrough at a wavelength suitable for the component gas 13CO2 is determined, and the concentration of the component gas is determined on the basis of a calibration curve prepared through measurement on test gas samples each containing the component gas in a known concentration. Further, the concentration of water vapor contained in the test gas sample is measured, and the concentration of the component gas in the test gas sample is corrected in accordance with the measured water vapor concentration on the basis of a correction curve prepared through measurement on the test gas samples each containing water vapor in a known concentration (FIG. 4). With the spectrometry, the concentration ratio of the component gas can precisely be determined and corrected by measuring the moisture content in the test gas sample.

Abstract: An apparatus for detecting a gas having distinct infrared radiation absorption characteristics. The apparatus includes a spectral source/bolometer for conducting an electrical current and for producing an infrared radiation. The source/bolometer is disposed along an axis and has a temperature and a characteristic resistance, and the characteristic resistance is a predetermined function of the temperature. A return reflector is disposed along the axis beyond the gas such that at least a portion of the infrared radiation passing through the gas is reflected back through the gas to the source/bolometer. The apparatus also includes a driver/detector for driving a current through the source/bolometer, for determining the characteristic resistance, and for detecting the gas from a variation of the characteristic resistance.

Abstract: A gas sensor (10) exposed by diffusion to a gas flow and operable to measure the presence of a particular gas component of the gas flow. The sensor (10) comprises a base (20), a diffuser (34), a source (36), a detector (38), and a detection chamber (40). The diffuser (34) is interposed between the gas flow and the detection chamber (40). Thus, rather than directly exposing the source (36), detector (38), and other electronics to the full force of the gas flow, the gas is passed to and from the detection chamber (40) by diffusion. The source (36) radiates energy having a particular characteristic such that the energy is proportionally absorbed by the gas component. The detector (38) measures the presence of any unabsorbed energy and generates an output signal indicative thereof. The detection chamber (40) is coated with a material known to reflect the radiated energy.

Abstract: In a respiratory air flow measuring monitor, a subassembly for analyzing certain respiratory gases through infrared spectroscopy includes an infrared emitter and an infrared detector, the amount of energy detected by the detector corresponding to the concentration of the gas selected for analysis. The subassembly includes a gas sample chamber that utilizes an elliptical reflecting surface for the infrared light source. The light source and detector are both oriented longitudinally along the axis of the ellipse and the light source and detector are each located at the two focal points of the ellipse in order to optimize the light absorption reading. The gas content analyzer subassembly additionally incorporates various compensatory features, allowing for automatic temperature and pressure compensation.

Abstract: An apparatus for analyzing a spectrum includes an elongated source of light, a device for producing a spectrum of the light, a sample stage, and an array of photosensitive elements for detecting the spectrum and providing an output representative of an intensity of the spectrum as a function of wavelength. The sample stage is interposed between the elongated source and the spectrum-producing device. The light propagates along a length of the sample stage from the elongated source to the spectrum-producing device. The elongated source has a length greater than or equal to a length of the array.

Abstract: The invention concerns a method for wavelength calibration of an electromagnetic radiation filtering device (16) included in an apparatus (10; 32) measuring spectral transmission of a propagating medium external to said apparatus and wherein said radiation flows through, said filtering device having spectral transmission tuneable on a wavelength range based on the value of a physical parameter. The invention is characterized in that it consists in: selecting at least one absorbing gaseous line which is always present in natural form in the propagation medium and whereof the corresponding wavelength is included in said filtering device tunability wavelength range; and in calibrating the filtering device with respect to said at least one absorbing gaseous line which is used as natural reference.

Abstract: An improved gas detector apparatus includes a spectral source/bolometer for conducting an electrical current and for producing infrared radiation. The source/bolometer has a characteristic resistance that is a predetermined function of the source/bolometer temperature. A concentrating reflector directs the infrared radiation through a spectral filter and the gas. A return reflector is disposed along the axis beyond the spectral filer and the gas, such that at least a portion of the infrared radiation passing through the filter and the gas is reflected back through the gas and the filter to the source/bolometer. A driver/detector drives a current through the source/bolometer, determines the characteristic resistance of the source/bolometer, and detects the gas from a variation of the characteristic resistance.

Abstract: A system and method that allows for early detection of biological conditions, such as a disease, through analysis of appropriate gaseous samples. The system and method are particularly amenable to the early screening for diseases, such as lung cancer, through the detection of specific biomarkers when present in exhaled breath from an individual. A preferred system implements a CO overtone laser that generates radiation and directs it through a photoacoustic cell. The absorption of the radiation is detected acoustically, and the absorption characteristics are utilized in determining the presence of a specific biological condition.

Abstract: Changes in the concentration of a chemical, such as a gas, are determined using a non-linear chemical sensor which is subject to shifts in calibration over time. In order to minimize errors caused by such shifts in calibration a first infrared signal (Ig(1)) is measured and using an absorption value under an assumed chemical concentration (C(1)), a zero chemical signal Io(1) is calculated using the known physical law and mathematical relation Absorption=1−Ig/Io. A second infrared signal (Ig(2)) is then measured and the absorption value is calculated using the previously calculated zero chemical signal. A second concentration (C(2)) is then determined and the change in concentration is calculated by subtracting C(2) from C(1).

Abstract: In a respiratory air flow measuring monitor, a subassembly for analyzing certain respiratory gases through infrared spectroscopy includes an infrared emitter and an infrared detector, the amount of energy detected by the detector corresponding to the concentration of the gas selected for analysis. The subassembly includes a gas sample chamber that utilizes an elliptical reflecting surface for the infrared light source. The light source and detector are both oriented longitudinally along the axis of the ellipse and the light source and detector are each located at the two focal points of the ellipse in order to optimize the light absorption reading. The gas content analyzer subassembly additionally incorporates various compensatory features, allowing for automatic temperature and pressure compensation.

Abstract: A method an apparatus uses the narrow-band measurement of the absorption of given spectral lines of a gas using laser light sources, so that the spectrally resolved measurement of individual absorption lines, and thus the selection of an individual gas component, is possible. A laser diode which is operated at a higher temperature is correspondingly varied over a certain temperature region, wherein the selected spectral line is crossed. On the basis of absorption measurements, the method and sensor deliver the gas concentration, with a high selectivity.

Abstract: A portable system for the real time detection and measurement of one or several gases is a gaseous mixture is disclosed. Such systems can be applied to industrial domains in which gases are to be measured and particularly toxic, dangerous, or polluting gases are generated. The system uses absorption spectrometry of a gas from a gaseous medium of interest. The optical means is at least two laser diodes with matchable cavities to generate a first and second wavelength, a light beam mixer prism, a double refraction crystal rotating on a controlled table. The tuned beam causes the gas to be measured to fluoresce and emit a signal to an infrared radiation detector which can indicate the identity and magnitude of the gas being measured.

Abstract: In accordance with the present invention, a test gas sample containing carbon dioxide 13CO2 as a component gas is introduced into a cell, then the absorbance of light transmitted therethrough at a wavelength suitable for the component gas 13CO2 is determined, and the concentration of the component gas is determined on the basis of a calibration curve prepared through measurement on test gas samples each containing the component gas in a known concentration. Further, the concentration of water vapor contained in the test gas sample is measured, and the concentration of the component gas in the test gas sample is corrected in accordance with the measured water vapor concentration on the basis of a correction curve prepared through measurement on the test gas samples each containing water vapor in a known concentration. With the spectrometry, the concentration ratio of the component gas can precisely be determined and corrected by measuring the moisture content in the test gas sample.

Abstract: Provided is a process for measuring the amount of impurities in a gas sample filling a laser absorption spectroscopy analysis cell. The process includes calculating the value of a characteristic representative of the absorbance of the gas sample, from a measurement of the gas sample at a single given pressure, and quantifying the impurities on the basis of a predetermined law for the variation of the characteristic as a function of the amount of impurities. The characteristic is the ratio of the difference between the luminous intensity (Iana) of a light beam transmitted through the gas and the luminous intensity (Iref) of the incident beam to the luminous intensity (Iref) of the incident beam. The impurities are quantified on the basis of a value of the coefficient of proportionality between the amount of impurities and the characteristic, determined on the basis of a table of variation of the characteristic as a function of pressure, for a given amount of impurities.

Abstract: A low noise amplifier circuit modulates input signals at a frequency of about 1 kHz, subsequently demodulates and filters the signals to provide an analog DC output level in which the 1/f noise of the amplifier is effectively eliminated due to the selection of the modulation frequency above the significant level of 1/f noise. Its application in a preferred embodiment is in an NDIR system using a detector having a DC emitter employed with a thermopile detector to provide an analog varying DC low level signal.

Abstract: The present invention relates to a system and method for selecting a detection bandwidth centered about a characteristic wavelength of the species to be detected and such that the detection of contaminants is greatly reduced. Contaminants such as pollutants, dust and water are some of the examples of undesirable substances which may be detected by RSD. By selecting the appropriate bandwidth in accordance with this invention, the detection of a desired substance can be separated from the undesirable detection of contaminants.

Abstract: An apparatus for analyzing a spectrum includes an elongated source of light, a device for producing a spectrum of the light, a sample stage, and an array of photosensitive elements for detecting the spectrum and providing an output representative of an intensity of the spectrum as a function of wavelength. The sample stage is interposed between the elongated source and the spectrum-producing device. The light propagates along a length of the sample stage from the elongated source to the spectrum-producing device. The elongated source has a length greater than or equal to a length of the array.

Abstract: An improved OBS based technique that monitors gas emissions from smoke stacks, tail pipes, and other sources, and that separates gas column density from thermal radiance contrast. The technique of the present invention utilizes a software generated digital filter (30) constructed to correlate with only the spectrum of gas (12) of interest, and have zero correlation with background components (22). Through using the improved OBS technique of the present invention, high performance and more positive cost effective gas monitoring systems and sensors may be built and implemented.

Abstract: A gas cell is provided for detection of trace gases via intracavity laser spectroscopy. The gas cell comprises a gas cell body having a long body axis, an interior hollow portion along the long body axis, and two end portions, each end portion having two opposed surfaces, one surface of each the end portion cut to an angle with respect to the long body axis and including a laser-transparent window on each face defining ends of the interior hollow portion. The angle is dependent on operating wavelength of the spectrometer and refractive index of the window material at the operating wavelength. Each end portion is provided with a gas line connection in the proximity of the opposed surface, one gas line for introducing a sample gas into the interior hollow portion and the other gas line for exhausting the sample gas from the interior portion. Further, a gas cell holder is provided for supporting and positioning the gas cell.

Abstract: A correction curve (FIG. 19) is prepared by plotting 12CO2 concentrations and 13CO2/12CO2 concentration ratios which are determined on the basis of a calibration curve and 13CO2 and 12CO2 absorbances of gaseous samples having the same 13CO2/12CO2 concentration ratio but known different 12CO2 concentrations. A gaseous test sample containing 13CO2 and 12CO2 as component gases is introduced into a cell, and spectrometrically measured. A 12CO2 concentration of the gaseous test sample is determined by way of the spectrometric measurement. A concentration ratio correction value is obtained on the basis of the correction curve and the 12CO2 concentration of the gaseous test sample thus determined. A measured 13CO2/12CO2 concentration ratio is divided by the concentration ratio correction value thus obtained for correction of the 13CO2/12CO2 concentration ratio. Thus, the measurement accuracy of the concentration ratios of the component gases can be improved.

Abstract: A transparent sheet 11 for transmitting an infrared ray therethrough is formed by laminating a PET sheet 5 on which a anti-fogging layer 4 can be formed easily and a PP sheet 12 with good infrared ray transmission property, thereby to make the thickness of the transparent window larger.

Abstract: The present invention relates to an apparatus configured for identification of a material and method of identifying a material. One embodiment of the present invention provides an apparatus configured for identification of a material including a first region configured to receive a first sample and output a first spectrum responsive to exposure of the first sample to radiation; a signal generator configured to provide a reference signal having a reference frequency and a modulation signal having a modulation frequency; a modulator configured to selectively modulate the first spectrum using the modulation signal according to the reference frequency; a second region configured to receive a second sample and output a second spectrum responsive to exposure of the second sample to the first spectrum; and a detector configured to detect the second spectrum.

Abstract: A system and method are set forth for photoacoustical analysis of isotope and other compounds having telltale absorption wavelengths between 1700-2500 nm. The system and method includes a Co:Mg F2, an optical parametric oscillator (OPO), or a diode laser tunable between 1700-2500 nm which is directed into a sample at energies sufficient to generate detectable acoustical emissions. A microphone detects the emissions for processing and analysis. The system and method is adapted to detect stable isotope compounds such as 13CO2 as well as other chemical compounds. For non-gaseous compounds, a CO2 or diode laser is used to photoablate the gaseous sample containing the suspected compound.

Abstract: The invention is directed to a disposable airway adapter which includes two optical windows and a reflector, positioned such that radiation transmitted through the first optical window into the airway passage will be reflected by the reflector and be transmitted through the second optical window and out of the airway passage. the disposable airway adapter is for use in connection with a carbon dioxide detector for determining the concentration of carbon dioxide present in the mixture of gases present in the airway passage.