Coincidence and Interference Corrections for Dual-Energy Gamma Ray Measurements of Soil Density and Water Content1
- R. S. Mansell,
- L. C. Hammond and
- R. M. McCurdy2
Coincidence and interference errors in the dual-energy gamma ray attenuation method are discussed for simultaneous determination of water content and bulk density of soil columns. Collimated radiation from 300 mCi each of 241Am and 137Cs provides a high intensity beam comprised of 60 and 662 keV photons. Count rates measured by a single detector and a two-channel gamma spectrometer were corrected for coincidence losses due to pulse-resolving time. The lower energy channel counts were also corrected for Compton scattering of Cs radiation and for a counting loss attributable to a special coincidence interference.
Mass attenuation coefficients were determined for glass beads, water, and eight soil materials. Errors in soil water content measurement by the dual-energy gamma attenuation method appears to be restricted to standard deviations of approximately 1% due to practical limitations in measurement precision of 60 and 662 keV attenuation coefficients for soil and water.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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