Parallax in angular sensitive powder diffraction tomography

TL;DR

This paper investigates the impact of geometric parallax in angular sensitive powder diffraction tomography, revealing it can be corrected straightforwardly and has no effect on angular reconstructions with full 360° scans.

Contribution

It provides a detailed analysis of parallax effects in diffraction tomography and demonstrates conditions under which parallax can be effectively corrected or ignored.

Findings

Parallax adds linearly to other offsets, allowing simple correction.

Full 360° rotations negate parallax effects on angular reconstructions.

Parallax correction improves depth-resolved strain distribution accuracy.

Abstract

While a few methods for the determination of depth-resolved strain distributions each with inherent limitations are available, tomographic reconstruction has been applied to this problem in only a limited sense. One of the challenges was the potential impact of geometric parallax, which constitutes a non-negligible lateral offset of diffraction information arising from different sample depths at the detector. Here, the effect of parallax was investigated and two main results have emerged. First, the impact of parallax was found to be additive to other offset contributions, which implies a straightforward correction. Second, for tomographic scans utilizing a full 360{\deg} rotation parallax has been found to have no impact on reconstructions of angular information.