(312e) Polymer Thin Film Platforms for the Rapid Detection and Analysis of Waterborne Radionuclides

The detection and isotopic analysis of uranium and plutonium special nuclear materials (SNM) in environmental waters is critical for nuclear forensics and nonproliferation efforts. Techniques for isolating and concentrating SNM for isotopic analysis are time-consuming and often have to be performed offsite. The ability to perform rapid, onsite analysis of waterborne SNM would be a powerful nuclear forensics tool; currently no such technology exists.

This presentation describes the use of SNM-selective polymer thin films for the isolation, detection, and isotopic analysis of waterborne SNM via alpha spectroscopy. The films were coated onto silicon wafers and porous membranes through spin coating. This method of film casting provided a high-degree of control over the thickness and surface uniformity. Several polymer film chemistries were compared for their ability to capture uranium and plutonium from water at low and circumneutral pH, and isotope peak resolution were determined for films with thicknesses from 25 to 250 nm. The films afforded high isotope peak resolutions, given as full width at half maximum, that were measured to be 30-60 keV. Application of the films as an SNM selective layer on the surface of macroporous membrane supports enabled the flow-through processing of large sample volumes and concentration of low-level SNM at the membrane surface for direct spectroscopic analysis. Results of this work are being used to develop a field-portable device for rapid detection and analysis of waterborne radionuclides.