Home | Survey | Topics | Index | References | Dictionary | Contributing | Gallery | Community
| Transmission fluctuations: Introduction | Prev topic | Next topic |
Transmission of light by dispersion is, among other factors, a function of the number concentration of particles in dispersion. Given that the number, N, of particles in a volume of dispersion is a Poisson-distributed random variable, the number of particles in different volumes of dispersion varies. The relative magnitude of these variations (fluctuations) equals 1/sqrt(N), i.e. increases with decreasing N. Thus, the transmission of light by a volume of dispersion, sufficiently small so that the relative magnitude of the particle number fluctuations is significant, does fluctuate as well.
Such fluctuations can be readily measured, for example, by measuring transmission of dispersion flowing past a stationary light beam. Gregory (1985) shown that by measuring transmission fluctuations, one can determine the concentration of monodisperse particles without needing to know or calculate optical properties of the particles such as the attenuation cross section. For monodisperse particles, this immediately leads to the determination of the particle size.
Transmission fluctuations have been more recently shown to enable the measurement of PSD. In this capacity, the measurement of transmission fluctuations is referred to as the transmission fluctuations spectrometry (TFS).
| CITATION: Jonasz M. 2006. Transmission fluctuations: Introduction (www.tpdsci.com/Tpc/TF.php). In: Top. Part. Disp. Sci. (www.tpdsci.com). |
HISTORY: Published: 17-Jan-2006 Modified: 03-Jul-2006 Peer-reviewed: 03-May-2006 |
| Copyright 2005-2008 MJC Optical Technology. All rights reserved. | Terms of use | Menu |