title: Raman spectroscopy of uranium compounds and the use of multivariate analysis for visualization and classification.
abstract: Raman spectroscopy was used on 95 samples comprising mainly of uranium ore concentrates as well as some UF4 and UO2 samples, in order to classify uranium compounds for nuclear forensic purposes, for the first time. This technique was selected as it is non-destructive and rapid. The spectra obtained from 9 different classes of chemical compounds were subjected to multivariate data analysis such as principal component analysis (PCA), partial least square-discriminant analysis (PLS-DA) and Fisher Discriminant Analysis (FDA). These classes were ammonium diuranate (ADU), sodium diuranate (SDU), ammonium uranyl carbonate (AUC), uranyl hydroxide (UH), UO2, UO3, UO4, U3O8 and UF4. Unsupervised PCA of full spectra shows fairly good distinction among the classes with some overlaps observed with ADU and UH. These overlaps are also reflected in the poorer specificities determined by PLS-DA. Higher values of sensitivities and specificities of remaining compounds were obtained. Supervised FDA based on reduced dataset of only 40 variables shows similar results to that of PCA but with closer clustering of ADU, UH, SDU, AUC. As a rapid and non-destructive technique, Raman spectroscopy is useful and complements existing techniques in multi-faceted nuclear forensics.
authors: European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany; DSO National Laboratories, 20 Science Park Drive, Singapore 118230. Electronic address: hmerlin@dso.org.sg.
authors: Doris Mer Lin
authors: DM
authors: Ho
authors: The University of Liverpool, Department of Electrical Engineering and Electronics, Brownlow Hill, Liverpool L69 3GJ, United Kingdom. Electronic address: A.Jones3@liverpool.ac.uk.
authors: Andrew E
authors: AE
authors: Jones
authors: The University of Liverpool, Department of Electrical Engineering and Electronics, Brownlow Hill, Liverpool L69 3GJ, United Kingdom.
authors: John Y
authors: JY
authors: Goulermas
authors: AWE, Aldermaston, Reading, Berkshire RG7 4PR, United Kingdom.
authors: Philip
authors: P
authors: Turner
authors: European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany.
authors: Zsolt
authors: Z
authors: Varga
authors: European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany.
authors: Lorenzo
authors: L
authors: Fongaro
authors: European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany; Ruprecht-Karls-Universität Heidelberg, Physikalisch-Chemisches Institut, Im Neuenheimer Feld, Germany.
authors: Thomas
authors: T
authors: Fanghänel
authors: European Commission, Joint Research Centre (JRC), Institute for Transuranium Elements (ITU), Postfach 2340, 76125 Karlsruhe, Germany.
authors: Klaus
authors: K
authors: Mayer
keywords: Multi-variate analysis; Nuclear forensics; Raman spectroscopy; Uranium ore concentrates