The Use Of Neutron Logging Methods For The Detection And Monitoring Of Chlorinated Solvents: A Quantitative Study

Laboratory experiments have been performed to quantify the ability of neutron<br>logging techniques to detect and monitor chlorinated solvent contamination in aquifers.<br>The effects of chlorine concentration and the spatial distribution of chlorine-rich layers<br>were investigated. The thermal neutron device responds significantly ( 20% or more<br>reduction in neutron count) to chlorine concentrations corresponding to relatively low<br>levels of perchloroethylene saturation (- 10 %). The sensitivity of the device to variations<br>in chlorine concentration is greater at low levels of chlorine content. A chlorine-rich layer<br>of 0.63 cm (0.25 in) thickness is detectable; however, visual thickness estimates are<br>difficult for thicknesses less than the source-detector length. Visual resolution of<br>individual thin layers requires layer separations greater than the source-detector length.