Ion Site Distribution Images Via X-Ray

In work at the APS Basic Energy Sciences Synchrotron Radiation Center, we have made the first direct images of ion site distributions at the mineral-water interface through x-ray standing wave imaging with Fourier synthesis. Direct images are crucial for understanding processes at mineral-water interfaces, such as weathering of rocks, the evolution of petroleum reserves and ore deposits, and the remediation of contaminants in groundwater.

The direct imaging approach we demonstrated is far faster than indirect methods used previously. Our approach was made possible by the brilliance of the APS x-ray beams, which allowed us to focus on a small, nearly perfect region of a large, imperfect crystal. Our ultimate goal is to learn to use x-rays to image geochemical process at the molecular level as they occur.
This work was supported by the DOE-BES Geosciences Research Program. We worked in collaboration with scientists at the University of Illinois at Chicago, Northwestern University, the Illinois State Water Survey, and ORNL.


Principal Investigator: Paul Fenter, ER Division, 2-7053