This project will create a new, unique synchrotron-based user facility to examine geologic materials at the micron scale with a focused X-ray beam tuned specifically for lighter elements Na through Ti. This facility is designed and optimized for "tender" (1-8 keV energy) X-ray micro-spectroscopy and imaging applications for Earth Science research, and will complement existing and highly productive "hard" X-ray facilities operating above about 4.5 keV. It will extend to lower energies the X-ray fluorescence (XRF) and X-ray absorption spectroscopy (XAS) capabilities typical of hard X-ray microprobes, as element-specific non-invasive probes of elemental distribution and local physical and electronic structures and states in crystalline and non-crystalline materials. In addition, it will offer advanced capabilities for microbeam extended X-ray absorption spectroscopy (EXAFS) for determination of more detailed local structure around the selected element.
This project will be undertaken by adding new micro-focusing capabilities at an established and proven macro-focused (~1mm spot size) tender-energy XAS beamline at X15B of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory, and will subsequently transition to the new Tender Energy Spectroscopy (TES) beamline under development at NSLS-II. Its key attributes will be the distinct 1 to 8 keV energy range, user-tunable spot size from about 50 microns to 1 micron, high flux and stability optimized for high-quality and extended XAS, options for both XRF and XAS mapping with rapid scanning, and a helium glove-box sample environment. Performance will improve when transferred to NSLS-II, a state-of-the-art new Synchrotron designed for high brightness applications. These new capabilities are critical for advancing our knowledge of geochemical and biogeochemical processes, in particular those involving lighter elements, and will be openly available for use through the NSLS General User program. Specific applications targeted include the mineral-water interface, nutrients and contaminants, carbonates, paleoclimate, redox processes, high-pressure mineralogy; and health effects of Earth materials.