Abstract
Compton scattering is generally neglected in diffraction experiments because the incoherent radiation it generates does not give rise to interference effects and therefore is negligible at Bragg peaks. However, as the scattering volume isreduced, the difference between the Rayleigh (coherent) and Compton (incoherent) contributions at Bragg peaks diminishes and the incoherent part may become substantial. The consequences can be significant for coherent diffraction imaging at high scattering angles: the incoherent radiation produces background that smears out the secondary interference fringes, affecting thus the achievable resolution of the technique. Here, a criterion that relates the object shape and the resolution is introduced. The Compton contribution for several object shapes is quantified, and it is shown that the maximum achievable resolution along different directions has a strong dependence on the crystal shape and size.
Highlights
In the last decade, the use of the coherence properties of X-rays produced at third-generation synchrotron radiation sources has markedly increased
We examine the simplest case where the total intensity is the sum of three terms: (a) the interference fringes, arising from the coherent scattering (Icoh); (b) the featureless background due to Compton scattering (Iinc); (c) a noise term (@): Itot 1⁄4 Icoh þ Iinc þ @: ð30Þ
We discuss the influence of Compton scattering for some simple cases that are often encountered in diffraction experiments and have analytical solutions
Summary
The use of the coherence properties of X-rays produced at third-generation synchrotron radiation sources has markedly increased. As widely discussed in the literature (Sinha et al, 1998; Whitehead et al, 2009; Nugent, 2010), washes out interference effects and compromises the inversion process or the achievable spatial resolution For this reason, the use of coherence preserving optics is especially important (Paganin, 2006). As a process that increases the background and reduces the fringe visibility, may lessen the maximum resolution that can be obtained in the reconstructions because it affects the signal-to-noise ratio, as we shall discuss below. This is important when the signal is weak, which is generally the case of BCDI experiments.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
