Abstract: At least one light source is configured to emit at least one beam into a sample volume of an absorbing medium. In addition, at least one detector is positioned to detect at least a portion of the beam emitted by the at least one light source. Further, at least one beam modification element is positioned between the at least one detector and the at least one light source to selectively change at least one of (i) a power intensity of, or (ii) a shape of the beam emitted by the at least one light source as detected by the at least one detector. A control circuit is coupled to the beam modification element. Related apparatus methods, articles of manufacture, systems, and the like are described.

Abstract: A first contact surface of a semiconductor laser chip can be formed to a target surface roughness selected to have a maximum peak to valley height that is substantially smaller than a barrier layer thickness of a metallic barrier layer to be applied to the first contact surface. A metallic barrier layer having the barrier layer thickness can be applied to the first contact surface, and the semiconductor laser chip can be soldered to a carrier mounting along the first contact surface using a solder composition by heating the soldering composition to less than a threshold temperature at which dissolution of the metallic barrier layer into the soldering composition occurs. Related systems, methods, articles of manufacture, and the like are also described.

Abstract: A reference harmonic absorption curve of a laser absorption spectrometer can have a reference curve shape derived from a reference signal generated by the detector in response to light passing from the laser light source through a reference gas or gas mixture. The reference gas or gas mixture can include one or more of a target analyte and a background gas expected to be present during analysis of the target analyte. A test harmonic absorption curve having a test curve shape is compared with the reference harmonic absorption curve to detect a difference between the test curve shape and the reference curve shape. Operating and/or analytical parameters of the laser absorption spectrometer are adjusted to correct the test curve shape to reduce the difference between the test curve shape and the reference curve shape.

Abstract: A first contact surface of a semiconductor laser chip can be formed to a first target surface roughness and a second contact surface of a carrier mounting can be formed to a second target surface roughness. A first bond preparation layer comprising a first metal can optionally be applied to the formed first contact surface, and a second bond preparation layer comprising a second metal can optionally be applied to the formed second contact surface. The first contact surface can be contacted with the second contact surface, and a solderless securing process can secure the semiconductor laser chip to the carrier mounting. Related systems, methods, articles of manufacture, and the like are also described.

Abstract: A first contact surface of a semiconductor laser chip can be formed to a target surface roughness selected to have a maximum peak to valley height that is substantially smaller than a barrier layer thickness. A barrier layer that includes a non-metallic, electrically-conducting compound and that has the barrier layer thickness can be applied to the first contact surface, and the semiconductor laser chip can be soldered to a carrier mounting along the first contact surface using a solder composition by heating the soldering composition to less than a threshold temperature at which dissolution of the barrier layer into the soldering composition occurs. Related systems, methods, articles of manufacture, and the like are also described.

Abstract: A sample cell can be designed to minimize excess gas volume. Described features can be advantageous in reducing an amount of gas required to flow through the sample cell during spectroscopic measurements, and in reducing a time (e.g. a total volume of gas) required to flush the cell between sampling events. In some examples, contours of the inners surfaces of the sample cell that contact the contained gas can be shaped, dimensioned, etc. such that a maximum clearance distance is provided between the inner surfaces at one or more locations. Systems, methods, and articles, etc. are described.

Abstract: A sample cell can be designed to minimize excess gas volume. Described features can be advantageous in reducing an amount of gas required to flow through the sample cell during spectroscopic measurements, and in reducing a time (e.g. a total volume of gas) required to flush the cell between sampling events. In some examples, contours of the inners surfaces of the sample cell that contact the contained gas can be shaped, dimensioned, etc. such that a maximum clearance distance is provided between the inner surfaces at one or more locations. Systems, methods, and articles, etc. are described.

Abstract: Validation verification data quantifying an intensity of light reaching a detector of a spectrometer from a light source of the spectrometer after the light passes through a validation gas across a known path length can be collected or received. The validation gas can include an amount of an analyte compound and an undisturbed background composition that is representative of a sample gas background composition of a sample gas to be analyzed using a spectrometer. The sample gas background composition can include one or more background components. The validation verification data can be compared with stored calibration data for the spectrometer to calculate a concentration adjustment factor, and sample measurement data collected with the spectrometer can be modified using this adjustment factor to compensate for collisional broadening of a spectral peak of the analyte compound by the background components. Related methods, articles of manufacture, systems, and the like are described.

Abstract: Light intensity data quantifying intensity of light generated by a light source and received at a detector during a validation mode of an absorption spectrometer can be compared with a stored data set representing at least one previous measurement in a validation mode of an analytical system. The validation mode can include causing the light to pass at least once through each of a zero gas and a reference gas contained within a validation cell and including a known amount of a target analyte. The zero gas can have at least one of known and negligible first light absorbance characteristics within a range of wavelengths produced by the light source. A validation failure can be determined to have occurred if the first light intensity data and the stored data set are out of agreement by more than a predefined threshold amount. Related systems, methods, and articles of manufacture are also described.

Abstract: A spectrometer cell can include a spacer, at least one end cap, and at least one mirror with a reflective surface. The end cap can be positioned proximate to a first contact end of the spacer such that the end cap and spacer at least partially enclose an internal volume of the spectrometer cell. The mirror can be secured in place by a mechanical attachment that includes attachment materials that are chemically inert to at least one reactive gas compound. The mechanical attachment can hold an optical axis of the reflective surface in a fixed orientation relative to other components of the spectrometer cell and or a spectrometer device that comprises the spectrometer cell. The mirror can optionally be constructed of a material such as stainless steel, ceramic, or the like. Related methods, articles of manufacture, systems, and the like are described.

Abstract: A reference harmonic absorption curve of a laser absorption spectrometer can have a reference curve shape derived from a reference signal generated by the detector in response to light passing from the laser light source through a reference gas or gas mixture. The reference gas or gas mixture can include one or more of a target analyte and a background gas expected to be present during analysis of the target analyte. A test harmonic absorption curve having a test curve shape is compared with the reference harmonic absorption curve to detect a difference between the test curve shape and the reference curve shape. Operating and/or analytical parameters of the laser absorption spectrometer are adjusted to correct the test curve shape to reduce the difference between the test curve shape and the reference curve shape.

Abstract: A reference harmonic absorption curve of a laser absorption spectrometer, which can include a tunable or scannable laser light source and a detector, can have a reference curve shape and can include a first, second, or higher order harmonic signal of a reference signal generated by the detector in response to light passing from the laser light source through a reference gas or gas mixture. The reference gas or gas mixture can include one or more of a target analyte and a background gas expected to be present during analysis of the target analyte. The reference harmonic absorption curve can have been determined for the laser absorption spectrometer in a known or calibrated state. A test harmonic absorption curve having a test curve shape is compared with the reference harmonic absorption curve to detect a difference between the test curve shape and the reference curve shape.

Abstract: A differential absorption spectrum for a reactive gas in a gas mixture can be generated for sample absorption data by subtracting background absorption data set from the sample absorption data. The background absorption data can be characteristic of absorption characteristics of the background composition in a laser light scan range that includes a target wavelength. The differential absorption spectrum can be converted to a measured concentration of the reactive gas using calibration data. A determination can be made whether the background composition has substantially changed relative to the background absorption data, and new background absorption data can be used if the background composition has substantially changed. Related systems, apparatus, methods, and/or articles are also described.

Abstract: A valid state of an analytical system that includes a light source and a detector can be verified by determining that deviation of first light intensity data quantifying a first intensity of light received at the detector from the light source after the light has passed at least once through each of a reference gas in a validation cell and a zero gas from a stored data set does not exceed a pre-defined threshold deviation. The stored data set can represent at least one previous measurement collected during a previous instrument validation process performed on the analytical system. The reference gas can include a known amount of an analyte. A concentration of the analyte in a sample gas can be determined by correcting second light intensity data quantifying a second intensity of the light received at the detector after the light passes at least once through each of the reference gas in the validation cell and a sample gas containing an unknown concentration of the analyte compound.

Abstract: An energy content meter can spectroscopically quantify oxidation products after oxidation of a combustible mixture. The measured oxidation product concentrations or mole fractions can be converted to an energy content of the un-oxidized combustible mixture using a conversion factor that relates oxygen consumption during oxidation of the combustible mixture to the energy content of the combustible mixture.

Abstract: Ambient temperature for a temperature sensor can be calculated using a mobile temperature sensor system that samples air from the boundary layer around a mobile platform and passes the air through a measurement cell containing two flush-mounted or embedded sensor elements. A common reference voltage can be applied by control circuitry to minimize drift in the sensor element readings and to calculate the ambient temperature.

Abstract: A differential absorption spectrum for a reactive gas in a gas mixture can be generated for sample absorption data by subtracting background absorption data set from the sample absorption data. The background absorption data can be characteristic of absorption characteristics of the background composition in a laser light scan range that includes a target wavelength. The differential absorption spectrum can be converted to a measured concentration of the reactive gas using calibration data. A determination can be made whether the background composition has substantially changed relative to the background absorption data, and new background absorption data can be used if the background composition has substantially changed. Related systems, apparatus, methods, and/or articles are also described.

Abstract: Thermally controlled enclosures that can be used with gas analyzers are described. The enclosures incorporate one or more phase changing materials that buffer ambient and internal heat loads to reduce the power consumption demand of mechanical or electronic heating apparatus. Maintenance of gas analyzer equipment at a consistent temperature can be important to achieving stable and reproducible results. Related systems, apparatus, methods, and/or articles are also described.

Abstract: Thermodynamic properties of a natural gas stream can be determined in real time utilizing modeling algorithms in conjunction with one or more sensors for quantifying physical and chemical properties of the natural gas. A first data signal produced by a first sensor can include intensity as a function of wavelength. At least one region in the wavelength range outside of a selected absorption transition can be fitted to a function to obtain a zero-absorption baseline, and a carbon dioxide concentration can be determined based on a line strength at the selected absorption transition corrected by the zero-absorption baseline. A total hydrocarbon concentration in the gas stream can be inferred based on a database of characteristic natural gas concentrations, and an algorithm can be implemented that determines an energy content of the gas stream. Related techniques, apparatus, systems, and articles are also described.

Abstract: Thermodynamic properties of a natural gas stream can be determined in real time utilizing modeling algorithms in conjunction with one or more sensors for quantifying physical and chemical properties of the natural gas. Related techniques, apparatus, systems, and articles are also described.