In the case of laser diffraction systems, the particle size reported is the diameter of a sphere that yields an equivalent light scattering pattern as the particle being measured. Laser diffraction works by measuring the angular variation in intensity of light scattered as a laser beam passes through a well dispersed sample. The angular scattering intensity received is then analyzed to calculate the size of the particles responsible for creating the scattering pattern. In laser diffraction a volume distribution is obtained, which shows the volume percentage of particles at a given size obtained. This technique provides rapid measurements and repeatability.

This instrument provides the opportunity for wet and dry measurements, while the light source operates at a wavelength of 633 nm. Utilizing the wet technique, the operator can measure particle sizes throughout a size range of 0.05 µm to 900 µm. The dry technique allows the user to quickly measure dry powders ranging from 0.5 µm to 900 µm.