Comparison of phase contrast X-ray computed tomography methods for non-destructive testing of materials
J. Kastner, B. Plank, V. Revol, C. Kottler - Comparison of phase contrast X-ray computed tomography methods for non-destructive testing of materials - Proceedings of 12th World Conference on Non-Destructive Testing, Durban, Süd Afrika, 2012, pp. 9
Currently the basis for standard X-ray computed tomography (CT) is absorption. A volumetric map of a specimen in three dimensions is generated from a set of absorption radiographs. The contrast of details strongly depends on a difference in absorption coefficient between the detail and the environment. However, when the absorption difference is low, sufficient contrast for a good quality X-ray image can be not obtained. During the last decade, a number of novel X-ray imaging methods have been developed, which are based on the phase shift of the X-ray beam passing through a material. This contrast mechanism allows for a significant increase of the contrast enhancing the interface. X-ray computed tomography phase imaging methods can be classified into (1) interferometric methods, (2) techniques using an analyser (or diffraction enhanced imaging) and (3) free space propagation based methods (also called in-line based methods). In this presentation, we compare an interferometric CT method based on the Talbot-Lau interferometer with propagation based phase contrast CTmethod and discuss the possibilities, advantages and restrictions in the field of non-destructive testing and evaluation.