The characterisation of airborne particles by analysis of spatial light scattering profiles

An instrument has been developed to investigate the potential characterisation of airborne particles, with particular reference to shape and size, by analysis of the spatial intensity distribution of scattered light. In the instrument the transient intensity distributions of light scattered from individual particles constrained by laminar airflow to traverse a focussed laser beam in single file are recorded by an intensified charge-coupled-device (CCD) camera as 2-dimensional photon distributions or scattering profiles. Experimental results are presented for a range of precision particle types, including those manufactured by the process of silicon micromachining.