POSSIBILITIES OF NEAR BACKWARD LIGHT-SCATTERING FOR CHARACTERIZING DENSE PARTICLE-SYSTEMS

A backscattering probe has been tested as an alternative to the more c ommon forward light scattering technique for particle size determinati on. The backscattering signature of an ensemble of spherical particles in front of the probe window was measured with a charged coupled devi ce (CCD) camera and compared with Lorenz-Mie calculations. The fringe structure allows the measurement of particle size. However, the width of the size distribution must be small to observe the fringes. The phe nomenon of enhanced backscattering in concentrated random particle med ia is investigated and discussed. The width of the coherent backscatte r peak, due to multiple scattering serves as an indicator for the mean particle size, independent of the shape of the particles. The total a mount of backscattered light is an indication of the total reflecting surface area of the sample.