 |
|
Absorption Contrast and XANES Absorption contrast and X-ray Absorption Near Edge Spectroscopy (XANES) both provide information on the chemical state of components in a sample. By taking an image above and below the absorption edge of an element, differences in intensity (i.e. darker images above the edge due to absorption by the element) can indicate presence of the element. This is demonstrated at the Fe K-edge of a meteorite fragment on this page. We also hope to do this above and below the calcium edge, for example, when working with bone, to distinguish calcium-containing tissue. This capability can also be used to provide better contrast with the use of heavy metal stains. Downloads & Links  If you would like to read the full research paper please click on the PDF icon to download the research paper that explores the new TXM imaging technology at SSRL. |
|
Imaging Samples Images below and above the Fe K-edge at 7101 and 7140 eV, respectively, of iron-rich crystallites in an olivine matrix. The dark areas in the 7140 eV image are due to absorption by iron. The dark areas in the 7101 eV image are features containing elements with high absorption at 7 keV.  Roots of cordgrass (Spartina foliosa) exposed to 1 ppm Hg for 7 days imaged in absorption contrast exhibit dense spherical particles along the outside of the root, mostly less than 1 micron in diameter, as visible in 6 x 6 mosaic at 9 keV (left), and single averaged image at 8 keV (right). The spherical particles are very dark due to absorption by Hg. |
|
