Scattering of 0.627-microm light from spheroidal 2-microm cladosporium and cubical 4-microm NaCI particles.

A digital polar nephalometer has been constructed to measure the intensity and polarization of light pulses scattered at 94 angles from 9 degrees to 176 degrees from monodisperse aerosol particles of controlled shape. The dye laser gave 20-kW, 4-nsec pulses at 0.627 microm. Data from polystyrene latex spheres agrees with Mie theory within about 10%. Data for spheroidal and quasi-cubical particles are shown. It is found that the backscatter from nonspherical particles of size parameter approximately 10 differs significantly from that for the best-fit sphere, so that a tumbled irregular particle is not equivalent to a sphere.