An Optical System with Brightness Amplification for Studying the Surface of Metal Nanopowders during Combustion

Abstract: The results of using an optical system with brightness amplification based on copper bromide vapors, which consisted of a laser monitor for studying the surface of an aluminum nanopowder during a high-temperature combustion process, are presented. A pulsed laser with a wavelength of 660 nm and the possibility of external synchronization was used to initiate the combustion process, thus making it possible to set the start time and the duration of the exposure. The average brightness of images of the brightness amplifier obtained by registering the output radiation with a photodiode is used to quantify the change in the reflection coefficient of the nanopowder surface and the time stages of the combustion process. The conventional scheme of a laser monitor with a focal length of 8 cm and a scheme with an increased focal length of 50 cm are considered. The possibility to perform quantitative analysis of processes during research using a laser monitor is shown. The error introduced to the measurement results by the instability of the lasing energy of the brightness amplifier is estimated. When observing the surface of the aluminum plate used as an object of research, the fluctuation in the average brightness of the laser-monitor images that was recorded with the photodiode did not exceed 5%.