Resolving Time, Mass Absorption Coefficient and Water Content with Gamma-Ray Attenuation1
- D. D. Fritton2
A method is described that was used to experimentally determine an intensity correction for gamma-ray attenuation. The correction is determined by using the minute nonlinearity of a semi-log plot of gamma-ray intensity versus the thickness or the product of thickness and density of a material. The experimentally determined correction is expressed in terms of resolving time and varied with both material and counting rate. A correction of 5.0 µsec/count was determined experimentally as the best resolving time to correct the observed counting rates for water content determination. Part of the 5.0 µsec/count correction was evidently due to causes other than resolving time. Mass absorption coefficients of water and soil were 0.08105 and 0.07309 cm2/g, respectively, with no correction and were 0.0871 and 0.0773 cm2/g with a 5.0 µsec/count correction. The difference between gravimetric water content and gamma-ray water content dropped from 3.02% to 0.60% when this correction was used.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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