Characterization of X-Ray Beam Profile Defined by Scatterless Slits Using a Pixel Array Detector

Small Angle X-Ray Scattering (SAXS) is an X-ray diffraction technique best suited for examining nanostructures on the scale of ~101  to 103  Å. Researchers who work with nanosystems, such as organic/inorganic/hybrid crystals, biomacromolecules, semiconductor devices, polymers, microfibers, etc, are able to obtain useful information about the nanoscale structures of their materials. To carry out precise measurements a sharp well-defined incident X-ray beam, and minimal parasitic scattering are imperative. The root cause of mediocre X-ray beams arises from parasitic scattering, in which the interaction of the beam-defining slit scatters the incident beam, thus producing undesired background (parasitic) noise. Resolving this issue involved designing hybrid slits with a single crystal edge of material fixed to a high density material. Previous work at the MRL x-ray facility has led to the development of the hybrid scatterless slits that drastically reduced parasitic scattering. The current work will focus on using the newly available x-ray pixel array detector to directly measure the full beam profile defined by the scatterless slits, which we could not do previously. This will allow us to characterize the beam defining properties of the hybrid slits using various candidate materials. The results will help the researchers to optimize the optical design of the slits and obtain higher resolution in SAXS instrumentation.

Faculty Advisor: Cyrus Safinya

Project Mentor: Miguel Zepeda-Rosales