Experimentally obtained and computer-simulated X-ray asymmetric eight-beam pinhole topographs for a silicon crystal

Acta Crystallogr A Found Adv. 2019 May 1;75(Pt 3):474-482. doi: 10.1107/S2053273319001499. Epub 2019 Apr 30.

Abstract

In this study, experimentally obtained eight-beam pinhole topographs for a silicon crystal using synchrotron X-rays were compared with computer-simulated images, and were found to be in good agreement. The experiment was performed with an asymmetric all-Laue geometry. However, the X-rays exited from both the bottom and side surfaces of the crystal. The simulations were performed using two different approaches: one was the integration of the n-beam Takagi-Taupin equation, and the second was the fast Fourier transformation of the X-ray amplitudes obtained by solving the eigenvalue problem of the n-beam Ewald-Laue theory as reported by Kohn & Khikhlukha [Acta Cryst. (2016), A72, 349-356] and Kohn [Acta Cryst. (2017), A73, 30-38].

Keywords: X-ray diffraction; computer simulation; dynamical theory; multiple reflection; n-beam reflection; phase problem; protein crystallography; silicon.