Advanced In-Situ Moisture Logging System


The Advanced In-Situ Moisture Logging System was designed to provide a system capable of measuring soil moisture content. This parameter is necessary to detect leakage or contaminant movement from a landfill or a contaminated soil site.

This technology consists of a neutron source made of radioactive americium/beryllium (10 mCi) and a detector. The source and detector are placed in close proximity to each other. The detector counts neutrons that have contacted hydrogen atoms, thus measuring soil moisture. Measurements are calibrated to soil moisture and soil density. This device has an approximate radius of influence of about 30 cm. This technique is similar to that used for many years in the mineral and oil industries. It differs only in the spacing between the source and detector. The mineral and oil industriesŐ probes are widely spaced to detect the presence of hydrogen over a much larger area, with a consequent decrease in precision.

Limitations and Concerns

Because it uses a radioactive source, it must be carefully handled and safely disposed.

This technique does not differentiate between hydrogen in water and hydrogen in the many contaminants found in landfills and other contaminated sites. Thus it can only be used as a preliminary characterization tool. If hydrogen is detected, more detailed characterization must be conducted.


This technology measures soil moisture in landfills and soil. It is not contaminant-specific.

Technology Development Status

A similar technology has been used for years in the oil industry to detect moisture and hydrocarbons. There is not enough information presented to know if this tool can be successfully adapted.

Web Links

Other Resources and Demonstrations

None have been identified.