How to avoid multiple scattering in strongly scattering SANS and USANS samples

•Multiple scattering effects studied through systematic SANS/USANS measurements.•Multiple scattering-minimized Q ranges are determined for each studied sample.•Optimum sample specific wavelength range are determined.•SAS-transmission (TSAS) of multiple scattering-minimized data is introduced.•An optimized approach to eliminate MS effects based on TSAS is proposed. Small Angle Neutron Scattering (SANS) and Ultra Small Angle Neutron Scattering (USANS) are the only available experimental techniques to provide seamless non-destructive measurements of the geometry of the accessible and inaccessible pore structure of rocks from sub-nanopore size to the scale of macropores. They have therefore become the measurement of choice for tight reservoir rocks such as organic rich shales. A simplifying assumption in the analysis is, however, that during the path of neutrons through the sample each neutron is only scattered once. Shales are samples with a high scattering power and Multiple Scattering (MS) may occur which requires special modelling for deconvolution of the results. The approach to avoid MS is to simply reduce the sample thickness to