الفهرس 
Cover EnglishOnly 14 pages are availabe for public view
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Abstract
Gas detection is one of the most important issues especially, concernin monitoring pollution. Many systems were designed for monitoring: CO2,NOx, SOx, O3 …etc. It is amid here to design a single homemade setup for gas detection and compare it with the already existing systems. Four multipass cells are used here one of them designed in this work. Two portable laser source were used in this investigation at 532 nm (2nd harmonic of diode pumped Nd:YAG laser with power of 0-250 mW) and 445 nm high power diode laser 0-1.5 watt. Four gases were involved in the present work,NO2, SO2, CO2 and smoke of cigarette.NO2 showed the best results in our investigations. We used in our investigation for detection Acton double monochromator (Acton spectrapro-500i), thorlab spectrometer (CCS100 Compact Spectrometer, 350 - 700 nm) in addition to fast photo-diode thorlab(DET210 - HIGH-SPEED SILICON DETECTOR) provided with digital storage oscilloscope. The results of the present work showed that homemade Barakat cell with all detection systems and proved to be the most reliable technique for NO2 detection with 445 nm diode laser. Finally it is prepared here to be this setup for a portable system to be used in open area for gas detection or pollution monitoring.