AN APPROACH TO IMPROVE THE ACCURACY OF SUBMICRON PARTICLE-SIZE DISTRIBUTION MEASUREMENT USING THE HORIBA-CAPA-700

An approach to improve the accuracy of the measurement of sub-micron particles using the Horiba CAPA-700 particle size analyser has been developed. A computer program has been written which corrects for the light scattering of small particles (<5 mum) using a modified Mie theory to calculate the light extension coefficient. An example using a mixture of two monodispersed spherical silica powders illustrates the importance of the correction and gives an accuracy of +/-5% for a 50/50 wt.% mixture. The limitations of the approach are also discussed.