A tube-excited X-ray fluorescence spectrometer for use in small-diameter boreholes

A portable in-situ x-ray fluorescence analytical system that uses an x-ray tube excitation source and a cooled Si(Li) spectrometer for detecting characteristic emission x rays has been developed for use in small-diameter wells and boreholes. The 15-watt, iron-anode x-ray tube operates up to 30 kV. Three wells at the Sandia National Laboratory Chemical Waste Landfill, lined with 76 thick polyethylene, were logged specifically for Cr contamination. Detection limits below 50 ppm were achieved with counting intervals of 600 seconds and with the Si(Li) detector operating at 450-eV resolution (full width at half maximum FWHM] for the Mn K-alpha x ray).