Water Content Measurement in Soil Columns by Gamma Ray Absorption

Abstract

A method of using gamma-ray absorption to measure the moisture content of a small volume of soil is described. The method appears promising in the study of unsaturated water flow, provided that the soil does not swell as water is applied, since measurements of both bulk density and water content can be obtained without disturbing the system. Water contents in a volume of soil about 1 cm. wide were measured to an accuracy of about ±0.5% by volume.

The effect of soil‐particle size on hydrocarbon entrapment near a dynamic water table

“…The instrument used in this study was a dualbeam gamma densitometer. The first gamma densitometry in soil analysis used a single monoenergetic beam (Ferguson and Gardner, 1962). A single beam was sufficient for measuring water content in a nonswelling medium.…”

A review of non-invasive imaging methods and applications in contaminant hydrogeology research

“…An important first use of gamma radiation imaging for contaminant hydrogeology research was to generate fluid saturations (Ferguson and Gardner, 1962; Fritton, 1969), in some cases to compute parameter values for saturation-pressure relations (Ferrand et al, 1986; Dane et al, 1992; Hofstee et al, 1997; White et al, 2004). Measurements with gamma radiation assure the determination of such curves locally within a porous medium, rather than providing data averaged over the total volume of a relatively large sample, as determined with typical pressure cells.…”

Survey of methods for soil moisture determination

“…The method first became known in the early 1950'x. Work by Gurr (1962), Ferguson and Gardner (1962), Davidson et al (1963), and Dmitriyev (1966) was instrumental in developing the theoretical basis and procedure for its use. A. major problem in many cold regions is the inability to measure in situ water conditions in the freezing, thawing or frozen state.…”