Radioactivity Whats the Use

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Radioactivity Whats the Use?

• Carbon-14 dating
• Radon
• Properties of uranium
• Medical diagnostics 99mTc
• Medical imaging PET scanning
• Study of 100Sn

03 Mar 29 Henry Griffin
Chemistry Jim Degenhardt Physics
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Types of decay

• Alpha decay
• 238U ? 234Th 4He (234Th 2e- 4He2)
• Beta decay
• 14C ? 14N ß- ?
• 22Na ? 22Ne e- ß ? Q 1022 keV
• 22Na ? 22Ne ? Q(energy)
• Gamma decay
• 137mBa ? 137Ba ?

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lepton
antilepton
?
N
_

• 14C ? 14N ß- ?

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8
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7
ß-
momentum
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Positrons from decay Of 84Rb
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Overview of radiocarbon dating

• 14C is produced in the upper atmosphere
  
• 14C mixes with carbon in biosphere
• Carbon is fixed into e.g. wood fiber
• 14C/carbon in wood fiber is measured

14N neutron 14C proton
Time passes
14C 14N e- ?
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14N n 14C 1H 782.4
-156.5 625.9 keV
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Select value 1 sd from exact For analysis
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Radon
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Radon (3.8-d 222Rn)

• 226Ra a decay dislodges Rn
• Radon moves into air, into lungs
• Radon decays, 218Po etc. on surface of lungs
• Radon descendents emit a particles into lung
  tissue
• Too much damage for repair

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Gamma-ray Spectrum catalogue, 4th Ed (1998).
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Gamma-ray Spectrum catalogue, 4th Ed (1998).
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Array of Ge ?-ray detectors at Nat.
Superconducting Cyclotron Lab. (MSU)
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Np-239 ? Pu-239
Gamma ray
L x rays
K x rays
a
ß
?
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Np-239 Pu-239
K X ray wider because of short half-life of
atomic excitation
Ka1
106.127-keV ?
Ka2