Range of validity of the Fraunhofer approximation in the estimation of particle size distributions from light diffraction

The inverse problem of retrieving the particle size distribution from the intensity of the diffracted field is solved using two numerical methods, the Chin-Shifrin algorithm and Singular Value Decomposition. The theory used in the inversion is based on the Fraunhofer approximation. We used the Lorenz-Mie theory to generate the intensity data produced from a series of normal size distributions. The distributions scan the interval of radius 0.1 micrometers < a < 17 micrometers . From our result we can set limits to the interval of particle size where the Fraunhofer approximation is valid.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.