Poisson’s spot is a diffraction phenomenon producing an intensity maximum at the center of the geometric shadow of circular opaque objects. In an analog of the Poisson spot experiment, we show that a tubular cone of x-rays incident upon a crystalline sample produces diffraction spots or foci, corresponding to Bragg maxima within a transmission shadow. We discuss the beam geometry and the intensity gain recorded at the foci in transmission mode. We describe the geometric growth and decay of the foci over a linear axis with the aid of a movie sequence synchronized with the plotting of a diffractogram. The mean signal of a small central area in each successive camera image provides the intensity data for the diffractogram.
High intensity x-ray diffraction in transmission mode employing an analog of Poisson’s spot
Paul Evans, Keith Rogers, Jer Chan, Joseph Rogers, Anthony Dicken; High intensity x-ray diffraction in transmission mode employing an analog of Poisson’s spot. Appl. Phys. Lett. 15 November 2010; 97 (20): 204101. https://doi.org/10.1063/1.3514235
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