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This article in SSSAJ

  1. Vol. 37 No. 4, p. 500-504
    Received: Dec 8, 1972
    Accepted: Mar 28, 1973

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Coincidence and Interference Corrections for Dual-Energy Gamma Ray Measurements of Soil Density and Water Content1

  1. R. S. Mansell,
  2. L. C. Hammond and
  3. 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.

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