Method and Apparatus for the Real-time Characterisation of Particles Suspended within a Fluid Medium.

This invention describes a method by which microparticles, typically in the size range from 0.3um to 100um, which are carried in a fluid suspension, may be rapidly detected and characterized. The method primarily relates to the measurement of atmospheric particles such as those in clouds or environmental aerosols, but it may be used to measure other forms of particulate suspension wherever the flow of suspension through a defined measurement space can be achieved. The method is based upon a rapid analysis of the spatial laser scattering profile (i.e., the complex manner in which individual particles scatter laser light) recorded from individual particles as they are carried in suspension through a measurement space. Using this method it is possible to differentiate various types of particles based on particle shape and structure, as manifest in characteristics of their individual spatial light scattering patterns. The sizes of spherical particles and the spherical equivalent sizes of non-spherical particles may also be determined, allowing size distribution for each particle type within the suspension to be determined. An implementation of the method for use in an aircraft mounted instrument is described.