MEASUREMENT OF SCATTERED INTENSITIES OF A MOVING AEROSOL PARTICLE AT TWO SCATTERING ANGLES : Characterization of airborne particles by optical properties

Abstract

An optical method for charcterizing a moving airborne particle is discussed in this study. The method isbased on Mie scattering theory, and refractive indices are used as a parameter of evaluating particles's characteristic. Refractive indices are obtained by measuring a pair of scattering intensities of a particle at different angles. It concludes as follows : (1) An optimal pair of scattering angles is examined by a numerical analysis. (2) An apparatus for the characterizaition of airborne particles (CAP system) is developed for the experiment. (3) The apparatus performance is evaluated by the experiment using PSL particles. The non-uniform intensity of laser beam has an effect on the changing intensity of scattered light. (4) The refractive index of test PSL particle is derived by the Mie analysis assuming the constant diameter.