title: X-ray diffraction tomography employing an annular beam.
abstract: We demonstrate depth-resolved materials characterization by scanning a sample through an annular beam of X-rays. We measure Bragg X-ray diffraction from a sample with a planar detector positioned centrally in a circular dark field defined by the annular beam. The diffraction maxima are optically encoded with the position of crystalline phases along this beam. Depth-resolved material phase images are recovered via tomosynthesis. We demonstrate our technique using a heterogeneous three-dimensional object comprising three different phases; cyclotetramethylene - tetranitramine, copper and nickel, distributed in a low density medium. Our technique has wide applicability in analytical imaging and is scalable with respect to both scan size and X-ray energy.
authors.forename: Paul
authors.initials: P
authors.lastname: Evans
authors.forename: Keith
authors.initials: K
authors.lastname: Rogers
authors.forename: Anthony
authors.initials: A
authors.lastname: Dicken
authors.forename: Simon
authors.initials: S
authors.lastname: Godber
authors.forename: Danae
authors.initials: D
authors.lastname: Prokopiou