Neutron Activation Analysis to Determine the Origin of Pottery Sherds

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Neutron Activation Analysis to Determine the
Origin of Pottery Sherds
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Our Investigation

• What was the relationship between large, urban
  centers and smaller agricultural villages like
  the one at Pulltrouser Swamp?
• Methods-
• Sample Cataloguing
• Sample Preparation
• Sample Activation
• Irradiation and Counting
• Sample Analysis

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Irradiation and Counting

• Looked for certain elements Co, Fe, Sc, etc.
• Following irradiation, 5000-second count (live
  time) of each sample after a 1-week decay period,
  and a 10000-second count (live time) after a
  period of 4 weeks decay, using a 30 efficiency
  HPGe detector.
• Explanation of equations used
• Absorption of Neutron
• 1n Ax ? A1x (radioactive)
• Beta Decay
• n? p v ß?
• Standard Deviation
• SD sqrt sum(xi xAvg.)2 / (n-1)
• Range
• Mean /- 2SD

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Data and Results
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Final Analysis and Deductions

• Achote Black samples are not similar to the
  redware found at Nohmul
• Mt. Pine Red samples, excluding sample KAX_005,
  have a 95 probability of being similar if not
  the same as the samples from Nohmul
• Because KAX_005 does not match the Nohmul samples
  on some elements, it is possible that the
  villages at Pulltrouser Swamp traded with other
  villages and regional centers.

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Future Areas for Investigation

• Find samples from other villages and regional
  centers near Pulltrouser Swamp
• Put samples through NAA process and Direct
  Comparison
• This would determine if the village at
  Pulltrouser Swamp traded with other villages
  besides Nohmul

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Connections to Bigger Picture

• Gives more understanding of Mayan Civilization
• Introduction of Swidden agriculture gave
  Pulltrouser Swamp an excess in food
• Pottery more valuable than food, so tribute could
  be issue