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Experimental Mechanics - Metal artifacts arising around high-density components are a widely known problem in X-ray computed tomography (XCT) for both medical and industrial applications. Although... 相似文献
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P. Tafforeau R. Boistel E. Boller A. Bravin M. Brunet Y. Chaimanee P. Cloetens M. Feist J. Hoszowska J.-J. Jaeger R.F. Kay V. Lazzari L. Marivaux A. Nel C. Nemoz X. Thibault P. Vignaud S. Zabler 《Applied Physics A: Materials Science & Processing》2006,83(2):195-202
Paleontologists are quite recent newcomers among the users of X-ray synchrotron imaging techniques at the European Synchrotron
Radiation Facility (ESRF). Studies of the external morphological characteristics of a fossil organism are not sufficient to
extract all the information for a paleontological study. Nowadays observations of internal structures become increasingly
important, but these observations should be non-destructive in order to preserve the important specimens. Conventional microtomography
allows performing part of these investigations. Nevertheless, the best microtomographic images are obtained using third-generation
synchrotrons producing hard X-rays, such as the ESRF. Firstly, monochromatisation avoids beam hardening that is frequently
strong for paleontological samples. Secondly, the high beam intensity available at synchrotron radiation sources allows rapid
data acquisition at very high spatial resolutions, resulting in precise mapping of the internal structures of the sample.
Thirdly, high coherence leads to additional imaging possibilities: phase contrast radiography, phase contrast microtomography
and holotomography. These methods greatly improve the image contrast and therefore allow studying fossils that cannot be investigated
by conventional microtomography due to a high degree of mineralisation or low absorption contrast. Thanks to these different
properties and imaging techniques, a synchrotron radiation source and the ESRF in particular appears as an almost ideal investigation
tool for paleontology.
PACS 01.30.Cc; 07.05.Hd; 68.37.Yz; 29.20.Lq; 81.70.Tx 相似文献
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Structural investigations of materials in diverse fields such as biomimetics, materials engineering, and medicine have much to benefit from 3D nondestructive microscopy of representative samples of wet tissues. Phase contrast appearing in tomograms produced by Fresnel propagation of partially coherent x-ray fields is useful for visualizing submicrometer features within water-immersed samples. However, spurious contributions such as those due to randomly appearing bubbles lead to distorted images. By improving the statistics during image acquisition and reconstruction, submicrometer-sized tubules in human tooth dentin are observed. This type of wet imaging is directly applicable to the study of many mineralized tissues. 相似文献
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