Abstract: The invention relates to an apparatus for the determination of a concentration of a component to be measured in a gas, comprising a light source, a wavelength selection unit, a measurement cuvette, a reference cuvette arranged in the optical beam path in parallel thereto, at least one light receiver and an evaluation unit which determines the concentration from the signals of the light receiver, wherein the gas to be analyzed is supplied to the measurement cuvette, on the one hand, and, on the other hand, to the reference cuvette via an absorption apparatus which includes a substance which completely absorbs the component to be measured. Further, the component to be measured is H2S and a wavelength selection unit is provided for the selection of an absorption wavelength.

Abstract: The invention relates to an apparatus for the determination of a concentration of a component to be measured in a gas, comprising a light source, a wavelength selection unit, a measurement cuvette, a reference cuvette arranged in the optical beam path in parallel thereto, at least one light receiver and an evaluation unit which determines the concentration from the signals of the light receiver, wherein the gas to be analyzed is supplied to the measurement cuvette, on the one hand, and, on the other hand, to the reference cuvette via an absorption apparatus which includes a substance which completely absorbs the component to be measured. Further, the component to be measured is H2S and a wavelength selection unit is provided for the selection of an absorption wavelength.

Abstract: A method for measuring NOx having a specific discharge lamp. The method controls a photometric analysis device, in which an electrically rotatable filter wheel or shutter wheel is used to change various shutters and/or filters in a beam path with beam source, cuvette and detector. The filter and/or shutter wheel is controlled in such a way that the measurement time is greater than the transfer time. This control improves the detection limit of the NOx resonance absorption method.

Abstract: A photometer for measuring gas components. The photometer has an infrared radiator with radiator modulation, a measuring cell with a measurement and comparison chamber, and a detector which absorbs optopneumatically onto the gas component X, that is filled with gas component X. In order in the case of a photometer of this type to render it possible for a plurality of gas components to be measured with high accuracy and the smallest possible outlay in apparatus, at least one further detector is arranged downstream of the first detector. For the purpose of measuring the gas component Y the further detector is filled with its isotope Y*, and the first detector is optically transparent with regard to the further gas component Y* to be measured or the characteristic absorption bands thereof.

Abstract: An electrodeless discharge lamp having a gas filling consisting of a gas mixture for generating gas-specific resonance radiation, wherein the lamp vessel is made of glass. To facilitate replacement and mounting of the electrodeless lamp, the discharge lamp is arranged within a metallic housing and the lamp vessel is disposed together with the high frequency coil as well as any electronic elements on a printed circuit board which is connected with the cover of the lamp housing.

Abstract: A sealed gas discharge lamp is filed with a water vapor-enriched low pressure nitrogen oxygen mixture and a storage medium such as manganese dioxide is included in a separate vessel of the lamp for additionally storing water vapor but releasing the water vapor as the pressure in the lamp drops, the release may be augmented by heating the storage medium.

Abstract: The invention relates to a process for Fabry-Perot spectroscopy using a spectrometer in the radiation path of which there is a radiation source, two successive Fabry-Perot interference filters through which the radiation passes, a blend of substances to be examined and a detector. The optical layer thickness of the first Fabry-Perot filter F1 is set to a given value and the optical layer thickness of the second Fabry-Perot filter F2 is modulated. The resultant interferogram as a function of the layer thickness is characteristic of the substance to be examined. The interferogram received at the detector D is converted by a mathematically transformation into a spectrum as a function of wave numbers.

Abstract: The life of a low-pressure, hollow cathode lamp with an oxygen/nitrogen filling is extended by the inclusion of MnO.sub.2 which releases oxygen, thereby replenishing oxygen consumption in the lamp.

Abstract: An analyzer for measuring the combined NO and NO.sub.2 concentrations includes a hollow cathode lamp with nitrogen/oxygen filling emitting radiation which is alternatingly passed through two narrow-band interference filters, one having a transmission range clearly outside any NO absorption bands and its NO.sub.2 absorption equals the difference of the absorption coefficients for NO and NO.sub.2 in the transmission band of the other filter. These two beams pass through a measuring gas cell and are photoelectrically detected for further processing.