In-Situ Sizing of Powders and Crystals Using Phase Doppler Measurement Technique

Phase Doppler technique is a non-intrusive optical device for in-situ measurement of single particles. In the case of an irregular particle, it provides a deterministic measure of particle velocity and statistical information about the particle size in the form of a phase shift signal. By collecting sufficient signals, velocity-resolved particle size distributions can be reconstructed. This is demonstrated by comparing phase Doppler measurements of irregular particles with an aerodynamic particle sizer. Preliminary measurements in a crystallizer are also presented. The present device is shown to work with near back-scatter collection of scattered light; hence, leads to a robust setup that can be used under the conditions of limited optical access.