SYNCHROTRON X-RAY-FLUORESCENCE MICROPROBE ANALYSIS WITH BENDING MAGNETS AND INSERTION DEVICES

The synchrotron X-ray fluorescence (SXRF) microprobe allows nondestructive trace element microanalyses of geological, biological and manmade materials. SXRF is complementary to other microanalytic techniques, such as PIXE and SIMS, and is advantageous because of its ppm sensitivity, low energy deposition, and ease of quantification. Disadvantages include the difficulty in producing micrometer-sized beams and the relatively large sampling depth (typically, tens of micrometers). Synchrotron source type is an important consideration in designing an X-ray microprobe and optimizing analytical conditions for a particular experiment. Bending magnet sources offer high polarization, reliability and availability. Superconducting wigglers offer higher flux at high energy (excitation of K fluorescence from heavy elements) but access is limited and polarization may be poorer. High energy undulators, such as those being built for the Advanced Photon Source (Argonne), provide very intense, broad band pseudo-monochromatic radiation that can be tuned to the absorption edge of interest. Recent experiments with the XRM on each of these sources are described as well as applications relevant to SXRF-PIXE intercomparisons.