Formation of informative signals in an optical toxic gas detector

Detection of various gas environments is an important security task, especially in conditions of military operations and in contaminated areas. In this case, optical gas sensors of the colorimetric type are effective, which can promptly signal the presence of toxic substances in "field conditions", do not require complex equipment or energy consumption. The object of the study is a detector of harmful gases of the colorimetric type. The problem of improving the characteristics of colorimetric sensors by amplifying useful signals and reducing the influence of spurious radiation is being solved. To solve the problem, a functional and mathematical model of the signal path of a pollutant detector was developed. A method for forming an optical signal of increased sensitivity due to multiple passage and reflection of light fluxes in a colorimetric sensor model was proposed. A model of an optical gas detector based on a polyaniline sensor element was manufactured. The presence of ammonia vapors was analyzed using gas-stimulated changes in optical absorption at different wavelengths, namely, 470 ± 5, 528 ± 7 and 623 ± 5 nm. The proposed functional scheme of the detector signal path allowed to improve its sensitivity and selectivity, which is explained by the amplification of useful signals and the reduction of9 the influence of parasitic radiation. The high speed of recovery of the resulting sensor to the initial values (up to 10 s) ensures its reversibility and opens up prospects for effective practical use, in particular, monitoring the state of the environment, the freshness of food products, harmful gas leaks near landfills, chemical storage sites, etc.