Global Distribution of Cs137

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Global Distribution of Cs-137

• Melissa Stellato

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Why is there a Global Distribution?

• Above ground nuclear testing creates fallout
• Homogenizes in the stratosphere

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Why Cs-137

• Has a well known gamma emission making it easy to
  measure
• Previous work with Pu 239 and 240
• Gives another baseline number
• Potential toxic effects, important to know if
  there are extraneous inputs
• Relatively long half life (30 years)

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Research

• Gamma spectrometry on 54 soil samples
• Create ratios and mixing lines
• Integrate the global fallout Cs-137 data with
  existing Pu isotope and Np data
• Develop the use of Cs-137 as a tool to resolve
  input of non fallout material

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How can you tell the difference between fallout
and other sources?

• Isotopic composition of a nuclear contaminant is
  dependent on its source
• Mixing lines

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Implications of Research

• Be aware of extraneous inputs
• Find the source