Determination of the largest microparticle diameter operating with the correlation function of small-angle scattering

A technique is provided which allows the direct determination of the maximum chord length L of the largest homogeneous particle of an isotropic two-phase system. The detailed analysis of the behavior of the three-dimensional correlation function of small-angle scattering (SAS) for extremely large r requires a special transformation. It allows an estimation of an upper limit Lmax of L with high precision. The exactness of the method depends on the shape of the particles in the direction of their biggest dimension. The most precise results are possible if there are not any tips, or if convex tips exist in the two points of penetration of the extremal chord through the particle surface. The method does not require any differentiation of the correlation function. The effect of statistical errors in the scattering experiment is investigated for realistic and simulated data.