Dr. Elizabeth Kautz
Materials Scientist
Pacific Northwest National Laboratory

Abstract

Laser-produced plasmas (LPP) are a resource-efficient, repeatable, tunable, lab-scale testbed for generation of plasmas, and for studying plasma chemistry.  Laser ablation (LA) and laser-produced plasmas (LPPs) are used extensively in several analytical applications, materials synthesis and forming, detection, and other areas such as light sources and medicine. LA is also considered a great laboratory testbed to evaluate spectroscopic signatures from high-explosive fireballs. The chemistry evolution in fireballs containing reactive species are of particular interest to national security and safeguards applications, in which understanding the gas-phase oxidation is critical to material detection, treaty verification, and explosion monitoring. This seminar will present recent investigations on the impact of plasma generation conditions on the interrelated phenomena of expansion dynamics, plasma chemistry, and physical conditions, with a focus on uranium LPPs. Plasmas were produced in the laboratory from a uranium metal target in air using nanosecond (ns), femtosecond (fs), and fs filament-assisted laser ablation. Several different plasma diagnostics were used to evaluate the spatio-temporal evolution of atoms, diatoms, polyatomic molecules, and nanoparticles in situ, including time-resolved fast-gated imaging, two-dimensional spectral imaging, and spatially integrated optical emission spectroscopy. On-going and future research directions related to tracking oxidation in LPPs from molecular to nanoparticle formation will also be discussed. In addition, methods and findings related to elemental and isotopic detection will be presented, including laser induced fluorescence of fs filament produced plasmas, and emission spectroscopy for hydrogen isotopic detection.

Biography

Dr. Elizabeth (Liz) Kautz is a Staff Scientist in the Energy and Environment Directorate at Pacific Northwest National Laboratory (PNNL) in Richland, WA. Her current research is focused on materials detection and monitoring using optical diagnostics and materials degradation phenomena, relevant to nuclear energy and non-proliferation applications. The majority of her work is sponsored by the Department of Energy National Nuclear Security Administration (DOE NNSA). Tools and techniques used in her research include several optical diagnostics for studying laser produced plasmas, and materials characterization techniques, such as electron microscopy and atom probe tomography. Prior to becoming a staff member, Liz was a Post Doctoral Research Associate in the National Security Directorate at PNNL. During her Post Doc, her research was focused on studying uranium gas-phase oxidation, uranium and zirconium alloy oxidation behavior (in the solid phase), and characterization of uranium-molybdenum metallic fuel microstructures to support fuel process development.

Liz received her Ph.D. in May 2018 from Rensselaer Polytechnic Institute (RPI) in Troy, NY. Her dissertation research focused on multi-length scale characterization of a uranium-molybdenum alloy, and incorporated several microscopy and image analysis techniques. Before her Ph.D. she held a position as a Materials Engineer at Knolls Atomic Power Laboratory (KAPL) located in Niskayuna, NY where she worked on a variety of projects related to zirconium alloy corrosion monitoring, kinetics of phase transformations during fuel manufacturing, irradiation testing, and fleet support. All of her work at KAPL supported materials development for application in the nuclear reactors that power U.S. submarines and aircraft carriers. While at KAPL, she earned her M.S. in Materials Engineering. Research for her M.S. degree was focused on monitoring phase transformations in zirconium-niobium alloys via thermal analysis. Liz also received her B.S. in Materials Engineering from RPI, graduating in 2010.