The proposal addresses the development of an integrated optic chemicalensor for cone penetrometers. The sensor is based on a novel, integrad optic interferometers. The unique design of this interferometer prodes a highly stable platform for measuring low concentrations of specic chemicals in both aqueous and gaseous environment. Sensing is accomshed by monitoring refractive index changes in thin-film surface coatis, with specificity for particular chemical determined by the choice osurface coatings. Multiple surface coatings can be used for simultanes detection of several chemicals. It is proposed to develop a completsmart sensor, including signal processing, local data analysis, on-boa data storage and a network/power interface, all based on the DoD Envinmental Systems Management, Analysis and Reporting Network (E-SMART) sndard. The smart sensor will be packaged as a cone penetrometer trailg module. Phase I proof-of-principle experiments and Phase II field donstration will be limited to detection of BETX chemicals (benzene, etl benzene, toluene and xylene). Nevertheless, the sensor will be desied such that it can subsequently be adapted for any number of chemicalpecies (e.g., chlorinated solvents, heavy metals) without changing thelectromechanical format or packaging. Anticipated
Benefits: The proposed sensor offers a number of key advantages for the DoD Siteharacterization and Analysis Penetrometer System (SCAPS); 1)it is sensivie (<= 1 part-per-billion), 2) it is rapid response (<= 1 second), 3it is fully reversible, 4) it neither generates nor is susceptible to terferences (e.g., electromagnetic fields, radiation, corrosive chemics), 5) it is compact (centimeter dimensions) 6) it is low power (<= 10milliWatts), and 7) it is low cost (<= $500). Moreover, the technologis applicable to a wide range of hazardous substances.
Keywords: chemical sensor, cone penetrometer, interferometer, integrated optics, groundwater