Effective Pinhole-Collimated Ultra-Small-Angle X-Ray Scattering Instrument for Measuring Anisotropic Microstructures
J Ilavsky, Andrew J. Allen, Gabrielle G. Long, P Jemain
Small-angle scattering is widely used for measuring materials microstructure in the 1 nm to 100 nm size range. Ultra-small-angle x-ray scattering (USAXS), typically achieved through crystal collimation, extends this size range to include features over 1 mm in size.This paper reports on USAXS on the UNICAT beam line 33-ID at the Advanced Photon Source. The instrument makes use of a six-reflection crystal pair as a collimator and another six-reflection crystal pair as an analyzer. First principle absolute calibration and a broad scattering vector range make this a very effective instrument, limited only by the fact that the measurement of anisotropic microstructures is excluded due to slit-smearing from the crystal collimation. This limitation has recently been removed by adding a horizontally reflecting crystal before and another after the sample. This creates a USAXS instrument with collimation in two orthogonal directions. We call this configuration effective pinhole USAXS. Now, anisotropic materials are probed using 9 keV - 17 keV photons in the same physically-relevant (from 50 nm to over 1 mm) microstructural size range as that available for materials which scatter isotropically.
, Allen, A.
, Long, G.
and Jemain, P.
Effective Pinhole-Collimated Ultra-Small-Angle X-Ray Scattering Instrument for Measuring Anisotropic Microstructures, Review of Scientific Instruments, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=850553
(Accessed December 2, 2023)