In-situ measurement of the water vapor concentration in industrial ovens by a user-friendly semiconductor laser system

Laser diodes are very promising tools for spectroscopic applications, e.g. for the contactless analysis of gases. We describe a prototype of a laser diode spectrometer which fulfills industrial requirements. We present results obtained at a brick-kiln over a period of several months. In this special application information about the moisture of the gas in the oven was required to optimize the baking process. In order to obtain an absorption signal without strong temperature dependence a special absorption line at (lambda) equals 1303.5 nm was selected. This wavelength was generated by a distributed feedback laser diode. Due to a normalization technique we obtained stable signals even at high dust loads within the measure volume.