MEASUREMENT OF PARTICLE-SIZE DISTRIBUTION AND VOLUME FRACTION IN CONCENTRATED SUSPENSIONS WITH PHOTON MIGRATION TECHNIQUES

The determination of the particle size distribution and the volume fra ction in concentrated suspensions from the multiwavelength measurement of isotropic-scattering coefficients by use of frequency-domain photo n migration techniques is demonstrated for three different polydispers e polystyrene suspensions. When a Newton-type inverse algorithm is use d, the successful recovery of the particle size distribution, in the f orm of a Weibull function, and the volume fraction of polystyrene susp ensions is achieved. Our results are in excellent agreement with dynam ic light-scattering size distribution measurements. On consideration o f the particle mass conservation as an additional constraint penalty t erm in the inverse algorithm, it is shown that the quality of the part icle size distribution reconstruction can be improved. Because no cali bration is needed, photon migration techniques are especially suited f or on-line measurement of the particle size distribution and the volum e fraction in the chemical- and the pharmaceutical based industries. ( C) 1997 Optical Society of America.