Abstract: Method and sensor for infrared measurement of gas comprising one infrared radiation source which illuminates two detectors at different distances from the radiation source, a spectrally selective element for infrared radiation adapted to be absorbed in a gas a to be measured arranged between the IR source and each of the detectors, and another infrared radiation source that illuminates those same two detectors possibly via a spectrally selective element for infrared radiation which by preference is not absorbed by any present gas. The radiation sources are excited at different patterns in time, and an electronic unit is adapted to select and separately amplify the resulting signals at said patterns from the detectors and to use the mutual ratios between such signals to calculate the concentration of said gas a.

Abstract: A method for identification, measurement and/or warning of a gas with a sensor composed of: a pulsed, radiation-cooled infrared radiation source heated by single pulses of electric current, an infrared detector which is adapted to the detection of pulsed infrared radiation from the radiation source, at least one infrared spectrally selective element arranged between the radiation source and the detector for spectral selection of the infrared radiation corresponding to specific spectral characteristics of the gas, a volume of gas that is arranged between the radiation source and the detector, optics arranged to guide infrared radiation from the radiation source via the spectrally selective element onto the detector through the volume of gas, and an electronics unit for registration, amplification, treatment and/or presentation of such electrical signals as result when the infrared radiation illuminates the detector through the gas via the spectrally selective element.

Abstract: Electrically pulsed infrared radiation source made from a thin foil-shaped material, which may be operated as required with temperature amplitudes of 100 K or more at millisecond pulse lengths. The source may be manufactured from known materials, and may be mounted in a preferred design as a curve-shaped bridge between two fixtures. The radiation source is particularly well adapted to be used in connection with pulse based methods and sensors for identification, measurement and warning of gas occurrences by means of infrared radiation. Examples of such methods and sensors are included in the invention.

Abstract: Pulsating infrared radiation source 50, which is so thin as to make its thermally stored energy less than the energy radiated during each pulse. This makes the source cooled by its own heat emission. Such sources have thicknesses commensurate with the wavelengths of infrared radiation. To avoid interference effects, the source's optical thickness may be made to equal a multiple of half wavelengths of the desired radiation. With the source mounted in a housing 53, efficient radiative cooling is obtained using windows 54 and 55 to each side. This makes it possible to extract infrared radiation from either face of the source.