title: Theory of oblique and grazing incidence Talbot‑Lau interferometers and demonstration in a compact source x‑ray reflective interferometer.
abstract: With the advent of Talbot-Lau interferometers for x-ray phase-contrast imaging, oblique and grazing incidence configurations are now used in the pursuit of sub-micron grating periods and high sensitivity. Here we address the question whether interferometers having oblique incident beams behave in the same way as the well-understood normal incidence ones, particularly when the grating planes are non-parallel. We derive the normal incidence equivalence of oblique incidence geometries from wave propagation modeling. Based on the theory, we propose a practical method to correct for non-parallelism of the grating planes, and demonstrate its effectiveness with a polychromatic hard x-ray reflective interferometer.
authors.affiliation: National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA. wenh@nhlbi.nih.gov
authors.forename: Han
authors.initials: H
authors.lastname: Wen
authors.forename: Camille K
authors.initials: CK
authors.lastname: Kemble
authors.forename: Eric E
authors.initials: EE
authors.lastname: Bennett
mesh_terms: D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007368:Interferometry / Q000295:instrumentation*; D008962:Models, Theoretical; D012542:Scattering, Radiation; D014961:X-Ray Diffraction / Q000295:instrumentation*; D014965:X-Rays