Particle analysis based on light scattering of particles illuminated by a divergent Gaussian beam

Light scattering by particles located in a divergent beam is developed recently as a new method for particle size measurement, which has the characteristics of broadening the range of measurable particle sizes and reducing the requirements for experimental equipment system. In this paper, a theoretical model is presented which takes into account the refraction of the light while passing across the interfaces of the media. Analytical expression, based on the ray propagation, is deduced to describe the scattered light distribution on the detector. In the experimental parts, particle size distributions are extracted from the measurements by using the inverse algorithm. The experimental evidence shows that all the measurements give reasonable results on the particle size distribution. The results are insensitive to the parameters of the optical arrangement. ► Present a new theoretical model for particles illuminated by a divergent beam. ► Deduce the analytical expression of the scattered light distribution. ► Using inverse algorithm to extract the particle size distributions. ► Experiments show the veracity and applicability of the theoretical model.