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Transcript of Applications of Nuclear Physics Chp 43.5 – 43.7. Biological Effects of Radiation Applications to...
![Page 1: Applications of Nuclear Physics Chp 43.5 – 43.7. Biological Effects of Radiation Applications to Astrophysics Nuclear Power.](https://reader036.fdocuments.in/reader036/viewer/2022062519/5697bfc61a28abf838ca738d/html5/thumbnails/1.jpg)
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 210Po 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; EK = 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
> 1000 Death in a few days
100 - 1000 Death in a few weeks
50 High probability of cancer in next 30 years
Type RBE
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 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
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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 + process – write the equation for this and predict the final product
• The positron emitted doesn’t get far!
18
9F
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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 1H 4He
• CNO cycle in higher mass stars
(link to astronomy notes)
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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!
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Supernovae and Nucleosynthesis
• Recall the binding energy curve…
Eb(MeV) per Nucleon
7.000
7.100
7.200
7.300
7.400
7.500
7.600
7.700
7.800
7.900
8.000
70 75 80 85 90 95
Z
Eb
(M
eV)
(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”?