Figure 18 shows a graphical representation of Fraunhofer and Mie models using scattering intensity, scattering angle, and particle size (ref. 13). The two modelsbegin to diverge around 20 microns and these differences become pronouncedbelow 10 microns. Put simply, the Fraunhofer Approximation contributes a magni-tude of error for micronized particles that is typically unacceptable to the user.A measurement of spherical glass beads is shown in Figure 19 and calculatedusing the Mie (red) and Fraunhofer (blue) models. The Mie result meets thematerial specification while the Fraunhofer result fails the specification and splitsthe peak. The over-reporting of small particles (where Fraunhofer error is signifi-cant) is a typical comparison result.