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Applications of Nuclear Physics Chp 43.5 – 43.7. Biological Effects of Radiation Applications to Astrophysics Nuclear Power.

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Presentation on theme: "Applications of Nuclear Physics Chp 43.5 – 43.7. Biological Effects of Radiation Applications to Astrophysics Nuclear Power."— Presentation transcript:

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 210 Po radiation poisoning It has been suggested that as little as 10  g 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 Po half-life is 138.4 d; E K = 5.41 MeV 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 (=100 rad) Relative biological effectiveness = RBE REM = rad X RBE Dose equivalent = absorbed dose X RBE in Sieverts = Sv (an older unit is the REM = 0.010 Sv) Dose (REM) Effect > 1000Death in a few days 100 - 1000Death in a few weeks 50High probability of cancer in next 30 years TypeRBE  10-20  1-2  1

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8 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

9 Fukushima Major radio nuclides being released are 137 Cs (t 1/2 = 30 a) and 131 I (t 1/2 = 8 d) A core breach exposes fuel rods Iodine concentrates in thyroid, Cs concentrates in muscle throughout body

10 Positron Emission Tomography fluorodeoxyglucose (FDG), C 6 H 11 FO 5 is a sugar that is commonly used in nuclear medicineFDG The fluorine atom is labeled – instead of “normal” F, it is This decays via a  + process – write the equation for this and predict the final product The positron emitted doesn’t get far!

11 Conservation Laws make this all possible!

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

13 Back of the envelope… Sun emits 3.99 x 10 26 J/s PP-chain fusion reaction releases about 25 MeV Solar Mass is 1.99 x 10 30 kg From this we can estimate the life expectancy of the Sun!

14 Supernovae and Nucleosynthesis Recall the binding energy curve… (link to astronomy notes)link to astronomy notes

15 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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