General formula for determination of cross-section from measured SANS intensities

A detailed derivation of the formula connecting measured SANS intensity wit h the smeared cross-section (raw-data treatment) is presented. The derivati on is carried out considering also a possible high probability of the coher ent small-angle scattering. The information content of the so-called transm ission measurement is analyzed. The individual effects which contribute to the primary-beam attenuation as well as the different modes of the transmis sion measurement are described. Multiple scattering contribution to the exc ess of the forward scattering of the water calibration standard is discusse d.