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Nuclear Technique in Forensic Science

Nuclear Technique in Forensic Science. Ta-Chung Ong NCSS. What is Nuclear Forensic?. Extract information from evidence Radioactive material What? Where? When? Isotopic composition Place of origin Age Track the material, solve the crime. Applications. Homeland Security Nuclear Weapon

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Nuclear Technique in Forensic Science

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  1. Nuclear Technique in Forensic Science Ta-Chung Ong NCSS

  2. What is Nuclear Forensic? • Extract information from evidence • Radioactive material • What? Where? When? • Isotopic composition • Place of origin • Age • Track the material, solve the crime

  3. Applications • Homeland Security • Nuclear Weapon • Dirty Bomb • Drug Law Enforcement • Thorium and methamphetamine • Elemental Analysis • “Red Mercury” hoax

  4. Homeland Security • Danger of nuclear proliferation after Cold War • Soviet nuclear material (U and Pu) • Lack proper security • Close proximity to unfriendly nations (i.e. Iran) and terrorist organizations (i.e. Al-Qaeda) • Some material seized in Germany and Czech Republic

  5. Homeland Security • Seized material as evidence • Origin determination • Isotopic composition (fingerprint) • Pinpoint place of production • Age determination • Parent/daughter ratio • Determine time of last purification

  6. Homeland Security • Isotopic Composition • Measure ratio of 234U, 235U, 236U, 238U, 239Pu, 240Pu, and 242Pu • Mass Spectrometry • Match result to database of known material • Pinpoint place of production

  7. Homeland Security • Age Determination • Parent/Daughter Ratio: 234U/230Th and 235U/231Pa • Th and Pa are in small concentration • Need accurate and precise separation • Solvent Extraction Chromatography • Alpha and Gamma Spectroscopy

  8. Drug Law Enforcement • ThO2 • Catalyst in the synthesis of phenylacetone (P2P) from acetic and phenylacetic acid • P2P is an intermediate in the synthesis of methamphetamine • Determine source and age of ThO2 seized in clandestine lab

  9. Drug Law Enforcement • Determine source of purified ThO2 • No detectable U • 232Th/230Th pair (not parent/daughter!) • Calculate 238U • Reveal composition of 232Th and 238U • Match result to ore database, determine ore body

  10. Drug Law Enforcement • Determine age of ThO2 • 232Th/228Th pair (parent/daughter) • 232Th, 228Ra, 228Th equilibrium (ore) • No 228Ra in purified ThO2 • Smaller amount of 228Th in purified sample than ore

  11. Elemental Analysis • Elemental Composition of metal • X-ray fluorescence • Gamma and alpha spectroscopy

  12. Elemental Analysis • Example: Red Mercury hoax • Mythical ballotechnic substance (emit energetic gamma ray) • Can trigger fusion • Make portable H-bomb possible • Never have been found

  13. Elemental Analysis • Perpetration of the hoax • Existence strongly advocated by Sam Cohen, inventor of neutron bomb • Black Market and would-be terrorists • Price of Red Mercury: $500,000/Kg • Advertised as ballotechnic, or highly enriched uranium, or component to missile guidance system

  14. Elemental Analysis • Analysis of seized “Red Mercury” in Livermore National Lab • Brownish red liquid • X-ray fluorescence: Mostly Hg, some Cd, Ag, and Zn • Gamma Spectroscopy: Indistinguishable from background • Conclusion: Ordinary mercury!

  15. Elemental Analysis • Possible candidate for Red Mercury • Cinnabar (HgS) • HgI2 (Red Color) • Any other mercury or mercury oxide with red pigment • Codename for something else, not mercury at all • Search continues…

  16. Conclusion • Nuclear Forensic • Extract Information from seized evidence • Isotopic Composition • Place of origin/production • Age • Provide valuable aid in criminal investigation

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