Abstract: A method for determining a sulfur trioxide content in a gas. A sample of the gas is taken, and a gas pressure of the sample is reduced. A wave number-resolved transmission measurement is carried out on the sample using a wave number-tunable monochrome light source, and a sulfur trioxide content is derived from the measurement. The measurement is carried out in the sulfur trioxide absorption band between 1360 and 1410 cm?1, in particular in a window around the sulfur trioxide absorption at 1365.49 cm?1. A method for operating a power plant, a measuring system for determining a sulfur trioxide content in a gas, and a power plant are adapted to determine a sulfur trioxide content in a gas.

Abstract: A method for determining a sulfur trioxide content in a gas. A sample of the gas is taken, and a gas pressure of the sample is reduced. A wave number-resolved transmission measurement is carried out on the sample using a wave number-tunable monochrome light source, and a sulfur trioxide content is derived from the measurement. The measurement is carried out in the sulfur trioxide absorption band between 1360 and 1410 cm?1, in particular in a window around the sulfur trioxide absorption at 1365.49 cm?1. A method for operating a power plant, a measuring system for determining a sulfur trioxide content in a gas, and a power plant are adapted to determine a sulfur trioxide content in a gas.

Abstract: A method and a sensor for detecting a target gas by laser spectroscopy using a laser or a laser diode having a monochrome emission wavelength that can be modulated by varying the operating temperature or the operating current. The wavelength range of the target gas comprises a first modulation of the laser or the laser diode over a first large modulation width, in addition to at least two absorption lines of a reference gas and at least one absorption line of the target gas. The absorption lines are used to calibrate the wavelength scale of the laser or the laser diode in relation to the varied operating temperature or operating current, a second modulation of the laser or the laser diode being performed over a second small modulation width, with the at least one absorption line of the target gas, for detecting the target gas.

Abstract: An optical measuring cell for measuring gas absorption with a light source for introducing light into a measuring volume and a light sensor located approximately opposite the light source in the direction of light propagation and relative to the measuring volume for receiving light that is guided through the measuring volume is provided. The concentration of one or multiple target gases in the measuring volume is detected by an evaluation unit. The measuring volume is constituted by an internal volume of a hollow fiber having an internal diameter less than 1 mm.

Abstract: An optical gas measurement using a Vertical Cavity Surface-Emitting Laser (VCSEL) and a hollow waveguide connected thereto, wherein the hollow waveguide contains a gas to be measured and conducts light. To this end, the hollow waveguide is made to vibrate. The gas measurement is performed and integrated over a period of time. As a result, disturbances of the measurement caused by interferences are considerably reduced.

Abstract: A method for controlling or monitoring firing systems and for monitoring buildings having gas burners using spectroscopy, provides at least one wavelength-tunable monochromatic light source. An absorption spectrum of a measuring gas is received with at least one photodetector in an absorption path with spectral tuning of the light source, and the concentration of target gases carbon monoxide (CO) and methane (CH4) can be determined simultaneously during tuning of the light source. A device for carrying out the method includes a monochromatic laser diode, in particular a VCSEL, an absorption path in the exhaust gas region or a space endangered by leakage, a photodetector for receiving light passed through the absorption path, and an evaluation unit for determining the concentration of target gases based on the absorption spectrum covered during the laser or laser diode tuning. The method and device are applied in laser-optical gas sensors in gas firing systems.

Abstract: A method and a sensor for detecting a target gas by laser spectroscopy using a laser or a laser diode having a monochrome emission wavelength that can be modulated by varying the operating temperature or the operating current. The wavelength range of the target gas comprises a first modulation of the laser or the laser diode over a first large modulation width, in addition to at least two absorption lines of a reference gas and at least one absorption line of the target gas. The absorption lines are used to calibrate the wavelength scale of the laser or the laser diode in relation to the varied operating temperature or operating current, a second modulation of the laser or the laser diode being performed over a second small modulation width, with the at least one absorption line of the target gas, for detecting the target gas.

Abstract: An optical measuring cell for measuring gas absorption with a light source for introducing light into a measuring volume and a light sensor located approximately opposite the light source in the direction of light propagation and relative to the measuring volume for receiving light that is guided through the measuring volume is provided. The concentration of one or multiple target gases in the measuring volume is detected by an evaluation unit. The measuring volume is constituted by an internal volume of a hollow fiber having an internal diameter less than 1 mm.

Abstract: The invention relates to a device for monitoring the oxygen concentration in an aircraft tank. The device includes an absorption measuring section equipped with a laser or laser diode (6), a photodiode (7), a temperature sensor (8) and a reflector (5) for carrying out laser spectroscopy on a gas volume to be measured inside the tank. The conducting components of the device are positioned outside the tank and its reflector (5) is positioned in the tank in the gas volume to be measured, the components and reflector being optically coupled by a window (3) that is situated in the tank wall (2). The absorption measuring section is mainly located in the chamber containing the gas to be measured.

Abstract: The invention relates to a device for monitoring the oxygen concentration in an aircraft tank. The device includes an absorption measuring section equipped with a laser or laser diode (6), a photodiode (7), a temperature sensor (8) and a reflector (5) for carrying out laser spectroscopy on a gas volume to be measured inside the tank. The conducting components of the device are positioned outside the tank and its reflector (5) is positioned in the tank in the gas volume to be measured, the components and reflector being optically coupled by a window (3) that is situated in the tank wall (2). The absorption measuring section is mainly located in the chamber containing the gas to be measured.

Abstract: There is provided an integrated wavelength-stabilised laser source comprising: a laser diode; a temperature-stabilising heat pump in thermal communication with the laser diode; and at least one detector, encapsulated within a hermetically sealed package comprising a window for passing light from the laser diode to the exterior of the package.

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.