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Applications of Nuclear Physics Chp 43.5 – 43.7
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Biological Effects of Radiation Applications to Astrophysics Nuclear Power
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Medical Applications of Nuclear Energy
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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)
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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.
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“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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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
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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
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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!
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Conservation Laws make this all possible!
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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
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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!
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Supernovae and Nucleosynthesis Recall the binding energy curve… (link to astronomy notes)link to astronomy notes
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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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