Seeing ever finer Details with X-Rays

X-ray radiographic absorption imaging is an invaluable tool in medical diagnostics and materials science. For biological tissue samples, polymers, or fiber composites, however, the use of conventional X-ray radiography is limited due to their weak absorption. This is resolved at highly brilliant X-ray synchrotron or micro-focus sources by using phase-sensitive imaging methods to improve contrast. The requirements of the illuminating radiation mean, however, that hard x-ray phase-sensitive imaging has until now been impractical with more readily available x-ray sources, such as x-ray tubes. With the present work we show how a setup consisting of three transmission gratings can efficiently yield quantitative differential phase contrast images with conventional x-ray tubes. As opposed to existing techniques, the method requires no spatial or temporal coherence, is mechanically robust, and can be scaled up to large fields of view. The new method provides all the benefits of contrast enhanced phase-sensitive imaging, but yet is fully compatible with conventional absorption radiography. It is applicable to x-ray medical imaging, industrial non-destructive testing, and to other low-brilliance radiation, such as neutrons or atoms.

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Facility: SLS

Phase retrieval and differential phase-contrast imaging with low-brilliance X-ray source F. Pfeiffer, T. Weitkamp, O. Bunk, and C. David Nature Phys. 2, 258-261 (2006)