Application of computer assisted tomography (CAT) to gamma attenuation measurement of soil water content

Abstract

This paper demonstrates the successful application of computer assisted tomography (CAT) to �-ray attenuation measurements and the modification of a conventional gamma scanning system to enable changes in the spatial distribution of soil water content to be accurately monitored in soil columns. The relatively inexpensive gamma system has been shown to provide a resolution comparable to that obtainable with commercially available but extremely expensive X-ray CAT scanning systems. However, longer counting times are required with gamma radiation, thus limiting the usefulness of the technique for some soil water studies. A comparison of the efficiency of several source-detection combinations illustrates their relative advantages and disadvantages.