Nuclear Technique in Forensic Science

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