Light Extinction Photometer for Measurement of Particle Sizes in Polydispersions

Publisher Website
Google Scholar
Abstract
By application of the Mie theory of light scattering by spherical particles and Stokes' law of settling, a measurement of the extinction of a monochromatic light beam over a known pathlength through a turbid medium allows a determination of the particle size distribution within the medium. Apparatus was fabricated and used successfully for the determination of particle size distributions of interhalogen compounds suspended in liquid nitrogen. The optical probe assemblies were constructed of a size small enough to fit into a 10 cm vessel. Optical coupling was accomplished with flexible light guides between the light source, probes, and detectors. To eliminate errors due to changes in the light source intensity or detector sensitivity over the relatively long duration of a run, a continuous reference measurement was provided by optical sampling.