Date of Award
Doctor of Philosophy
Howard L. Hall
John D. Auxier II, Ashley C. Stowe, Christian Parigger
This work demonstrates the capability of a readily available, and portable Laser Induced Breakdown Spectroscopy (LIBS) systems to conduct field screening of samples with nuclear forensics interest.A hand-held device for laser-induced breakdown spectroscopy has been investigated for the determination of uranyl fluoride surface contamination. This research demonstrates the ability to successfully detect uranium on surfaces when using a low resolving power (λ/Δλ= 4000) [lambda/ delta lambda] spectrograph, with a 5mJ [milijoule] energy per 1 ns [nanosecond] pulsed laser radiation, available as a commercially packaged hand-held system. Sand/uranyl fluoride mixtures are prepared to simulate residue likely encountered during decontamination efforts at facilities that handle uranium hexafluoride. Detection limits are described for four uranium lines with one revealing the capability to detect uranium at a level of 250 parts-per-million. Advantages of the studied compact device include that location specific information can be obtained on-site to augment contamination identification.This work also demonstrates the capability of a readily potentially portable Laser Induced Breakdown Spectroscopy (LIBS) system to conduct macroscopic chemical mapping of uranium and iron in surrogate nuclear debris for sample interior and exterior surfaces, for the first time. Techniques focus on the mitigation of chemical and physical matrix effects of four uranium atomic emission lines, relatively free of interferences and of good analytical value. The acceptable data spatial resolution is 0.5 mm [millimeter]. A material fractionation pattern occurs and is discussed in terms of constituent melting temperatures and thermal gradients experienced during the cooling process is proposed.Finally, Areas of further research to advance portable LIBS capabilities for nuclear forensics are discussed.
Shattan, Michael Bernard, "Portable Laser-Induced Breakdown Spectroscopy for Nuclear Forensics Applications. " PhD diss., University of Tennessee, 2018.
Available for download on Wednesday, May 15, 2019