Particle size analysis by transmission fluctuation Spectrometry with temporal correlation: Theory and Simulations on particle overlapping

Transmission fluctuation spectrometry with temporal or spatial correlation is being developed as a new method of particle size analysis, in which the particle size distribution and particle concentration can be measured simultaneously. Based on the assumption of low particle concentrations, an analytical expression of the transmission fluctuation correlation spectrum can be obtained With a layer model. It is found that the measurement matches the theory very well as long as the particle concentration is low enough. However, as the particle concentration increases, the measured transmission fluctuation spectrum deviates gradually from the theory, which is a result from the high concentration effects. The high concentration effects include particle overlapping and the monolayer structure. In this work, the theory and simulations on the particle overlapping are studied. As a result, an empirical expression is found.