Application of X-ray fluorescence analysis in well logging

X-ray fluorescence analysis can be used for studying all elements with atomic number greater than 24. Most suitable is the use of a pair of balanced differential filters for improving resolution and a probe with a dual proportional detector. Using such a system, element concentrations lower than 0.1% can be detected. Drill experiments use two- or three-channel analyzers and other electronic equipment for processing differences and ratios of measured pulse rates. If lower resolution is sufficient for elements to be determined, the so-called point evaluation of the quantitative element occurence is used. The energy spectrum is measured at one point and the result is compared to standard spectra. A multi-channel analyzer is used for the measurement. (H.S.)