Evaluation Of A Non-Destructive Xrf Analytical Tool For Uranium And Thorium Abundances And Radioactivity Assessment In Dimension Stone

Event Center A & B

The increasing popularity of “granite” dimension stone countertop materials, and their use in homes, illustrates the need for a nondestructive test for radioactivity and potentially harmful elements. The range of values for uranium and thorium in common countertop materials are within appropriate ranges of reliability for portable X-ray fluorescence (XRF) units. The correction curve for uranium has a correlation coefficient of 0.993, showing that raw XRF values may be corrected with a high degree of reliability. The correction curve for thorium also had a very strong correlation value of 0.999. Plots of U, Th, and U+Th vs. radioactivity measured for individual samples, shows correlation between radioactivity and the abundance of these elements. Specifically, there is moderate correlation of radioactivity with U abundance, stronger correlation with Th, and the best correlation with U+Th. This suggests that portable XRF units can serve as a useful screening tool for granite countertop materials with respect to U and Th levels, and can serve as a proxy for Geiger counter measurements of radioactivity within these same materials. This should prove useful for this presently unregulated industry, should future regulations require these types of measurements.