Project highlight. Portable, discrete radiation detection is imperative for nuclear safeguards applications, radioactive 3D imaging, and neutron spectroscopy. Current neutron detectors, including gas proportional counters and scintillators, are not suitable for discrete or portable monitoring due to size, weight, and power limitations. Perovskite based semiconductors have the potential to overcome existing issues with current nuclear detectors and exceed the performance of traditional semiconducting detecting materials. The goal of this project is to create novel boron (10 B) based single crystal perovskites for low-profile solid-state neutron detection. Directly incorporating the neutron capturing element (10 B) into the unit cell of the detector eliminates the energy diminishing routes that typically occur in indirect conversion materials, including self-absorption and interlayer energy transfer routes. Intellectual Property Review This report has been reviewed by SRNL Legal Counsel for intellectual property considerations and is approved to be publicly published in its current form.

The objective of this work is to adapt ambient ionization mass spectrometry (AMS) techniques for the rapid analysis of intact uranium complexes, stable strontium, cerium, and explosive compounds. The methods used were "soft ionization" techniques, which facilitate the detection of whole molecule complexes. The soft ionization mass spectrometry (MS) techniques that were investigated include paper spray ionization (PSI), matrix-assisted ionization (MAI), electrospray ionization (ESI) and direct analysis in real time (DART). For the first time, PSI-MS methods were successfully developed for whole molecule uranium-containing analytes (uranyl acetate, uranyl nitrate, and uranyl-tributylphosphate complexes). This was also the first demonstration of uranium complex detection and characterization and one of the few examples of inorganic analysis using MAI techniques. Proof of concept experiments also putatively identified matrix-derived ions and ion complexes that have not previously been described in the literature. Additionally, PSI-MS on cotton swipe samples doped with a multi-element standard containing µg levels of U, Bi, Pb, Cd, Fe, and Zn were directly analyzed without purification, representing a major improvement over existing methods. Both PSI and MAI methods demonstrated limits of detection (LODs) in the 10-100's ng for various uranyl species within a range of 10's ppm-100's ppb, dependent on analytical method and analyte species. AMS methods were also developed for other inorganics, including Ce and Sr, and organic explosive residues to address specific challenges in environmental monitoring and forensics. Further refinement and qualification of the AMS techniques developed within this effort would lead to significant cost reduction and timeliness by facilitating the triage and queueing of samples for subsequent more sensitive and time-consuming analyses. Awards and Recognition One manuscript has been submitted to the peer-reviewed Journal of the American Society for Mass Spectrometry titled "Matrix Assisted Ionization of Molecular Uranium Species". A manuscript on the rapid detection of inorganic Strontium and Cerium species by ambient mass spectrometry techniques is in preparation and will be submitted to Journal of the American Society for Mass Spectrometry. Intellectual Property Review This report has been reviewed by SRNL Legal Counsel for intellectual property considerations and is approved to be publicly published in its current form.

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The goal of this project is to develop a novel multifunctional fluorescence based sensors for the simultaneous detection of specific threats with high selectivity, high confidence, and reduced false positives, which will overcome current sensor limitations. The development of miniaturized sensors can be used as visual indicators for exposure or remote sampling of chemical threats, technologies that are pertinent for DoD, first responders, medical surveillance, and more.

Determining uranium isotopic and concentration information from environmental samples typically involves extensive chemical and physical processing prior to analysis. Harsh sample preparation results in the loss of the original uranium chemical speciation (i.e. what the uranium was bonded to/with when found in the environment) as well as the mixing of anthropogenic uranium with background material contained within the collection media (e.g. a swipe or soil). The objective of this work is to adapt a bioanalytical mass spectrometry technology called paper spray ionization mass spectrometry for the rapid analysis of intact uranium complexes. Soft ionization facilitates detection of whole molecule uranyl complexes including uranyl acetate, uranyl nitrate, and uranyl-tributylphosphate complex. Cotton swipe samples doped with a multielement standard containing µg levels of U, Bi, Pb, Cd, Fe, and Zn were directly analyzed without purification, representing a major improvement over existing methods. Uranium quantitation is demonstrated using internal standards to obtain linear calibration curves. Limits of detection were determined to be approximately 100 ng for UO2 and uranyl acetate through measurement of ppb level solutions. The development and qualification of PSI-MS techniques could lead to significant safeguards-related cost reduction and timeliness by facilitating the triage and queueing of swipe samples for more sensitive and time-consuming analyses. Awards and Recognition Technical aspects of the project have been accepted for presentation at the Southeastern Region American Chemical Society (SERMACS) meeting in Augusta, GA in October 2018. Intellectual Property Review This report has been reviewed by SRNL Legal Counsel for intellectual property considerations and is approved to be publicly published in its current form.