This award will support the operation and further development of an x-ray fluorescence microprobe facility at the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. The facility is under the direction of Dr. Mark Rivers of the University of Chicago who will be in residence at the NSLS. The x-ray fluorescence microprobe is capable of quantitatively analyzing for many elements down to the 10-100 parts per billion concentration range with a spatial resolution of several microns in thin specimens. It is proving especially useful in analyzing microscopic phases found in diamonds, peridotite inclusions, and other samples of the Earth's upper mantle. In addition to such analyses, this project will technically improve the current probe system with the addition of x-ray focussing mirrors, monochromators, and adapt to the new superconducting wiggler beamline at NSLS.