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Applications of Nuclear Physics

Applications of Nuclear Physics. Chp 43.5 – 43.7. Biological Effects of Radiation Applications to Astrophysics Nuclear Power. Medical Applications of Nuclear Energy. The Strange Tale of Alexander Litvenenko.

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Applications of Nuclear Physics

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  1. Applications of Nuclear Physics Chp 43.5 – 43.7

  2. Biological Effects of Radiation • Applications to Astrophysics • Nuclear Power

  3. Medical Applications of Nuclear Energy

  4. The Strange Tale of Alexander Litvenenko • Former KGB agent and political “whistle blower” became suddenly ill on November 1, 2006 following a restaurant meeting with a Russian “agent” • Died three weeks later. He is believed to be the first confirmed case of deliberate 210Po radiation poisoning • It has been suggested that as little as 10 mg of Polonium was put in his tea – this would be a fatal dose! Alexander Litvenenko (1962-2006)

  5. The “perfect assassin” • Po is readily available and essentially un-regulated in small amounts • Is an alpha-emitter: Easy to transport safely and lethal if ingested • Does NOT emit gamma rays! • Completely tasteless in quantities that would be lethal • It is estimate that 1 g of Po introduced to an urban water supply could poison 20 million people with 10 million fatalities.

  6. “Back of the envelope…” • Assume it concentrates in the liver • Calculate the radiation exposure this represents • Ideas we need: • Units of radiation exposure: • Activity = Bq • Absorbed dose = Gray = Gy = 1.00 J/kg • Relative biological effectiveness = RBE • Dose equivalent = absorbed dose X RBE in Sieverts = Sv (an older unit is the REM = 0.010 Sv)

  7. Older terms • The Roentgen = amount of ionizing radiation producing 0.3 nC in 1 cc of air • 1 rad = amount of radiation which would deposit 0.01J/kg in any material • SI unit is the GRAY = 100 rad • When considering biological effects the REM is often used = rad X RBE

  8. Fukushima • Major radio nuclides being released are 137Cs (t1/2 = 30 a) and 131I (t1/2 = 8 d) • A core breach exposes fuel rods • Iodine concentrates in thyroid, Cs concentrates in muscle throughout body

  9. Positron Emission Tomography • fluorodeoxyglucose (FDG), C6H11FO5 is a sugar that is commonly used in nuclear medicine • The fluorine atom is labeled – instead of “normal” F, it is • This decays via a b+ process – write the equation for this and predict the final product • The positron emitted doesn’t get far!

  10. Conservation Laws make this all possible!

  11. Stellar Structure and Evolution • Hydrogen fusion in Solar Mass stars – the proton-proton cycle • 4 1H  4He • CNO cycle in higher mass stars (link to astronomy notes)

  12. Back of the envelope… • Sun emits 3.99 x 1026 J/s • PP-chain fusion reaction releases about 25 MeV • Solar Mass is 1.99 x 1030 kg • From this we can estimate the life expectancy of the Sun!

  13. Supernovae and Nucleosynthesis • Recall the binding energy curve… (link to astronomy notes)

  14. Questions to work on… • You are 1m from a 1 kg lump of pure radium! • What kind of radiation are you likely going to be exposed to? • Estimate the exposure you will receive in REM over 1 hour • What is your “prognosis”?

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