PIXE ANALYSIS IN MINERALOGY AND GEOCHEMISTRY

Proton-induced X-ray emission can be used to analyze geological sample s for a wide range of trace elements (including transition large-ion-l ithophile and high-field-strength elements, and, in favorable circumst ances, rare-earth elements) in a variety of minerals down to levels of a few parts per million. The analyses are simultaneous, multi-element , and nondestructive. focused beam of protons (spot sizes typically 5 x 5 mu m) can be used for point analyses, or the beam may be scanned o ver an area as large as 2 mm x 2 mm to provide a two-dimensional X-ray map of element distribution. The proton beam also may be used for nuc lear reaction analysis and proton-induced gamma-ray emission. These te chniques may be run concurrently with PIXE and are useful for analyzin g a sample for light elements such as Li, B and F, with detection limi ts in the region of 100 ppm.