MODELING BACKGROUND RADIATION IN OUR ENVIRONMENT USING GEOCHEMICAL DATA

DOE/NV/25946--2116

Aerial gamma ray surveys have many applications in geology and science in general, such as for locating mining prospects, defining radioactive plumes, and detecting nuclear weapons. Unfortunately there is currently no way to separate the natural gamma radiation of soil and rocks from that of containments such as radioactive plumes. This project uses the geochemistry of the bedrock collected from national databases, private companies, and the literature, to create forward models of aerial gamma ray surveys. We are developing this technique in an area in north central Arizona known as the Navajo Mines area, chosen for its optimal conditions for aerial gamma ray surveys and readily available data. Basic statistics are done on the U, K, and Th concentrations to best eliminate outliers created by the heavy concentration of U mines in the area. Using median concentrations of U, K, and Th we attempt to calculate the exposure rate of each bedrock unit, and the corresponding soil, in a mapping area. Alluvial units were difficult to model in this way, as they were sorted by age rather than similar composition. To model these units we sorted them into drainage basins to attempt to create a similarity in composition among units. With these models we are developing techniques to estimate the natural radiation generated by the geology of an area, making aerial gamma ray surveys more effective.

This work was done by National Security Technologies, LLC, under Contract No. DE-AC52-06NA25946 with the U.S. Department of Energy.