Particle Sizing by Laser Light Diffraction: Improvements in Optics and Algorithms

Abstract A major problem encountered in particle sizing by laser light diffraction concerns the inversion of the diffraction pattern measured in a given experiment. Conventional methods for solving the linear system obtained can not be used in this problem, because the matrix is ill‐conditioned and also because the diffraction pattern is usually determined with a low resolution annular diode detector. These problems may be solved with up to date optical detectors (linear CCD‐arrays comprising 1024 photodiodes) and refined inversion techniques (conjugate gradient method and the analytical formulation due to Shifrin). These two aspects are described in this paper. Two inversion methods are compared and experimental results are discussed.