Isotope Hygrometer for in situ Subsurface Characterization

Isotope hydrology is a powerful method to trace transport and dispersion of contaminants in the subsurface. Although widely applied, the method depends on sample analysis in specialized laboratories equipped with expensive and complex analysis tools. Small, rugged analyzers suitable for on-site monitoring will significantly boost applications of this unique analysis technique. A cost effective, optical isotope hygrometer for measuring d18O, d17O and dD in water samples is proposed. Targeted measurement precision is below 1 per mil. The sensor will operate in real time and will need no sample preparation. Emerging infrared laser diodes will be combined with wavelength modulation spectroscopy to measure the isotope sample composition. A shoebox sized device is targeted that will allow rugged fieldable instrumentation at targeted retail pricing of $15K. Commercial Applications and Other Benefits: Isotope hygrometers are increasingly applied to contaminant hydrogeology. They are valuable tools in understanding surface water movement and interaction with groundwater. They are utilized for mapping aquifers and conserving water supplies. Water is of enormous environmental importance and the proposed compact sensor technology can find application in food product authenticity, paleoclimatology, atmospheric chemistry, and biomedicine