The new method of real-time detection of ¹²⁹I₂, ¹²⁹I¹²⁷I, ¹²⁷I₂ and NO₂ in gases using tunable diode laser operating in the range of 632–637 nm

This paper develops the new selective real-time method of ¹²⁹I₂, ¹²⁹I¹²⁷I, ¹²⁷I₂ and NO₂ detection in gases. Measuring concentrations of molecular iodine is based on fluorescence exciting by the radiation of a tunable diode laser, operating in the red spectral region (632–637 nm), at two or three wavelengths corresponding to the centers of the absorption lines of ¹²⁹I₂, ¹²⁹I¹²⁷I and ¹²⁷I₂. Detection of NO₂ is performed by measuring the intensity of the tunable diode laser radiation, which passed through the measuring cell. Measured simultaneously, boundary ratios of iodine molecule concentrations measured simultaneously are about 10⁻⁶. The sensitivity of nitrogen dioxide detection is 10¹⁶ cm⁻³. (letter)