A technique has been developed for determining the Sauter mean droplet diameter in a nozzle spray by direct analysis of the small angle, forward scattered light profile. The spatial intensity of the profile was scanned with a microphotometer and the information recorded on punched paper tape for later reduction by computer. A knowledge of a particular functional form for the intensity profile was required for computer processing of the data, and it was therefore determined empirically that the natural log of the intensity of the small angle, forward scattered light had a gaussian profile with respect to the scattering half-angle.
R. H. Dieck and R. L. Roberts, "The Determination of the Sauter Mean Droplet Diameter in Fuel Nozzle Sprays," Appl. Opt. 9, 2007-2014 (1970)