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oai:www.ideals.illinois.edu:2142/102954 2023-07-11 col_2142_14787 col_2142_5131 com_2142_9630 com_2142_234 com_2142_5130

The student, Emily Weerakkody, submitted this Thesis for approval on 2018-12-10 at 17:23. This Thesis was approved for publication on 2018-12-11 at 09:53. DSpace SAF Submission Ingestion Package generated from Vireo submission #13275 on 2019-02-08 at 11:41:45 Glumac, Nick G. Weerakkody, Emily Nelum 2019-02-08T18:44:42Z 2019-02-08T18:44:42Z 2021-02-09T10:15:38Z 2018-12-11 2018-12 Spectroscopy in its many utilities presents the ability to remotely sense species present in potentially hazardous conditions. Of recent interest is the development of technologies to detect the presence of actinide materials, a group of radioactive species typically used in the manufacture of nuclear devices. Current spectral databases are incomplete with regard to less-studied materials, such as the actinide group. In order to assist in the development of this technology, the spectral signatures of these materials need to be found and catalogued. Laser-induced breakdown spectroscopy (LIBS) is a commonly-used method to observe the spectra of materials in plasma conditions. This technique was used in conjunction with absorption spectroscopy, which provides the ability to determine concentration. Tests were performed on two samples, a pure Uranium sample, and an alloy of U3¬Si2, in order to determine changes in spectral signatures when ablated in various environments of different composition and pressure. The Uranium sample was first tested in varying concentrations of O2, N2, and Ar to observe changes in U I and U II species signatures. It was then tested targeting the UO transition at 593.55 nm to observe trends with ambient O2 concentration, pressure, laser power, and spatial location in plasma. The U3Si2 sample was tested to observe and compare temporal changes in U I, U II, Si I, UO, and SiO species signatures. Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2020-12-01 The student, Emily Weerakkody, accepted the attached license on 2018-12-10 at 17:14. Made available in DSpace on 2019-02-08T18:44:42Z (GMT). No. of bitstreams: 2 WEERAKKODY-THESIS-2018.pdf: 3599408 bytes, checksum: 348fb0a011a0951c21e3934c10b89348 (MD5) LICENSE.txt: 4213 bytes, checksum: eae533f0135863d18ffa227a4dfda2ce (MD5) Previous issue date: 2018-12-11 Embargo set by: Seth Robbins for item 109982 Lift date: 2021-02-08T18:44:50Z Reason: Author requested closed access (OA after 2yrs) in Vireo ETD system Limited Restriction Lifted for Item 109982 on 2021-02-09T10:15:38Z. application/pdf http://hdl.handle.net/2142/102954 en Copyright 2018 Emily Nelum Weerakkody Laser-Induced Breakdown Spectroscopy, Uranium, Absorption Spectroscopy, Uranium Oxides Use of absorption laser-induced breakdown spectroscopy in characterization of actinide species and oxides text text Mechanical Sci & Engineering Mechanical Engineering University of Illinois at Urbana-Champaign Thesis M.S.