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Ultra-Small-Angle Neutron Scattering with Azimuthal Asymmetry



X. Gu, David F. Mildner


Small-angle neutron scattering (SANS) measurements from thin rock samples such as shales demand as great a scattering vector range as possible because the pores cover a wide range of sizes. The limitation of the scattering vector range for pinhole SANS requires slit-smeared ultra-SANS measurements that need to be converted to pinhole geometry. Scattering from samples cut parallel to the plane of bedding is symmetric, exhibiting circular contours on a two-dimensional detector. Samples cut perpendicular to bedding show elliptical contours of the SANS measurement. The desmearing is only successful for azimuthally symmetric data. Instead the aspect ratio from the SANS data is used to modify the slit-smeared USANS data to produce quasi-symmetric contours. Rotation of the sample about the incident beam may result in symmetric data but it cannot extract the same information obtained from pinhole geometry.
Journal of Applied Crystallography


azimuthal asymmetric scattering, double crystal diffractometer, elliptic scattering contours, slit-height smeared scattering, small-anglr neutron scatterng


Gu, X. and Mildner, D. (2016), Ultra-Small-Angle Neutron Scattering with Azimuthal Asymmetry, Journal of Applied Crystallography, [online], (Accessed June 14, 2024)


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Created May 31, 2016, Updated October 12, 2021