Browsing by Author "Kristo, MJ"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Item
    The application of radiochronometry during the 4th collaborative materials exercise of the nuclear forensics international technical working group (ITWG)
    (Springer Nature, 2018-02-06) Kristo, MJ; Williams, R; Gaffney, AM; Kayzar-Boggs, TM; Schorzman, KC; Lagerkvist, P; Vesterlund, A; Ramebäck, H; Nelwamondo, AN; Kotze, D; Song, K; Lim, SH; Han, SH; Lee, CG; Okubo, A; Maloubier, D; Cardona, D; Samuleev, P; Dimayuga, I; Varga, Z; Wallenius, M; Mayer, K; Loi, E; Keegan, EA; Harrison, JJ; Thiruvoth, S; Stanley, FE; Spencer, KJ; Tandon, L
    In a recent international exercise, 10 international nuclear forensics laboratories successfully performed radiochronometry on three low enriched uranium oxide samples, providing 12 analytical results using three different parent-daughter pairs serving as independent chronometers. The vast majority of the results were consistent with one another and consistent with the known processing history of the materials. In general, for these particular samples, mass spectrometry gave more accurate and more precise analytical results than decay counting measurements. In addition, the concordance of the 235U–231Pa and 234U–230Th chronometers confirmed the validity of the age dating assumptions, increasing confidence in the resulting conclusions. © 2018 U.S. Government
  • No Thumbnail Available
    Item
    Nuclear forensic analysis of an unknown uranium ore concentrate sample seized in a criminal investigation in Australia
    (Elsevier, 2014-07) Keegan, EA; Kristo, MJ; Colella, M; Robel, M; Williams, R; Lindvall, R; Eppich, G; Roberts, SK; Borg, L; Gaffney, AM; Plaue, J; Wong, HKY; Davis, J; Loi, E; Reinhard, MI; Hutcheon, I
    Early in 2009, a state policing agency raided a clandestine drug laboratory in a suburb of a major city in Australia. During the search of the laboratory, a small glass jar labelled “Gamma Source” and containing a green powder was discovered. The powder was radioactive. This paper documents the detailed nuclear forensic analysis undertaken to characterise and identify the material and determine its provenance. Isotopic and impurity content, phase composition, microstructure and other characteristics were measured on the seized sample, and the results were compared with similar material obtained from the suspected source (ore and ore concentrate material). While an extensive range of parameters were measured, the key ‘nuclear forensic signatures’ used to identify the material were the U isotopic composition, Pb and Sr isotope ratios, and the rare earth element pattern. These measurements, in combination with statistical analysis of the elemental and isotopic content of the material against a database of uranium ore concentrates sourced from mines located worldwide, led to the conclusion that the seized material (a uranium ore concentrate of natural isotopic abundance) most likely originated from Mary Kathleen, a former Australian uranium mine. © 2014 Elsevier Ireland Ltd.
  • No Thumbnail Available
    Item
    Nuclear forensics: scientific analysis supporting law enforcement and nuclear security investigations
    (American Chemical Society, 2015-12-24) Keegan, EA; Kristo, MJ; Toole, K; Kips, R; Young, EL
    Nuclear forensic science, or "nuclear forensic", aims to answer questions about nuclear material found outside of regulatory control. In this Feature, we provide a general overview of nuclear forensics, selecting examples of key "nuclear forensic signatures" which have allowed investigators to determine the identity of unknown nuclear material in real investigations. © 2015 American Chemical Society