ON THE OPTICAL DIAGNOSIS AND SIZING OF SPHERICAL COATED AND MULTILAYERED PARTICLES WITH PHASE-DOPPLER ANEMOMETRY

After having recalled basic theoretical results concerning the extensi on of generalized Lorenz-Mie theory to the case of multilayered sphere s, results connected with phase-Doppler anemometry are considered, sho wing the influence of Gaussian beam intensity profiles on the light sc attering properties of these particles. Particular emphasis is placed on the case of water-coated carbon core particles, for which the possi bility of obtaining simultaneous size measurements of the core and out er diameters is discussed. The sensitivity of the technique to particl es with a refractive index profile is also considered, showing that th is technique is more sensitive to changes in the average refractive in dex of the particles than to refractive index profiles, such as produc ed by high pressure and temperature stresses, at least for the studied geometry.