X-ray phase contrast and fluorescence nanotomography for material studies

The macroscopic properties of many materials are determined by structural features spanning a wide range of length scales. The nano-imaging endstation ID22NI of the European Synchrotron Radiation Facility is optimized for nanoscale imaging (X-ray focus size well below 100 nm) at high X-ray energy (17-29 keV), making it possible to study the interior of dense samples with a millimetric size. Computed tomography and computed laminography setups allow three dimensional imaging of a wide variety of samples, laminography being especially suited for non-destructive imaging of flat samples. The focused X-rays are used as a scanning probe for fluorescence tomography, providing sensitivity for elemental composition down to the ppm level. Projection microscopy with phase contrast is used for imaging the electron density in an extremely sensitive way. We demonstrate these capabilities by imaging a Be pebble. We found large scale cracks and nanoporosity (<1 mu m pores). Furthermore, beryllium oxide inclusions could be detected, ranging from 200 nm to several microns in size. Some of the smallest inclusions were located next to a small pore, indicating beryllium oxide formation after solidification of the structure.