Award Date

May 2017

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry and Biochemistry

First Committee Member

Ken Czerwinski

Second Committee Member

Marianne Wilkerson

Third Committee Member

Gary Cerefice

Fourth Committee Member

Samuel Clegg

Fifth Committee Member

Benjamin Burton-Pye

Sixth Committee Member

Alexander Barzilov

Number of Pages

238

Abstract

Chemical speciation offers opportunities for development of signatures that arise from the production, conversion, and aging processes of nuclear materials. This information has been useful for environmental science and remediation and the ability to measure chemical signatures, from processed materials may be of great use to nuclear forensics. Many nuclear forensics analyses deal with radiochronometry and isotopic analysis, but because processing is chemical in nature, there are opportunities for chemical signatures from the bulk products, reagents, or reaction intermediates to be measured.

Many spectroscopic techniques can be utilized in a remote setting outside of the laboratory, with minimal or no sample preparation. Vibrational methods such as Raman and Infrared Spectroscopies can be useful for determining molecular structure and impurities. Photoluminescence spectroscopy can determine the chemical nature of samples. Laser Induced Breakdown Spectroscopy can be used to determine elemental impurities and has been shown to be useful for differentiating between samples of similar chemical nature.

A set of uranium compounds found throughout the life cycle of uranium, from mining to reprocessing, have been synthesized. These compounds range from tetravalent oxides and fluorides to hexavalent uranyl compounds and uranium ore concentrates. Raman and FTIR spectroscopy are used to determine differences in the vibrational spectroscopy with changes in the uranium speciation. A multivariate principal component model has been built for both the Raman and the FTIR spectra to determine and observe trends within data. Photoluminescence spectroscopy can determine differences in the electronic structure and luminescence emission characteristics of the set of uranium compounds. Laser Induced Breakdown Spectroscopy has the ability to determine the elemental composition of the uranium compounds. Ratios between emission line intensities have been compared with mass ratios to determine the ability to differentiate between uranium compounds. A multivariate principal component model has been built for the LIBS data to determine the spectral trends.

Keywords

FTIR; LIBS; PCA; Photoluminescence; Raman; Uranium

Disciplines

Chemistry

File Format

pdf

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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