PIXE applications: Mesoamerican pottery analysis. Kelsey Falter, Stephanie House, Sarah Kimball, Anna Gabrielle O Meara O

Transcription

1 PIXE applications: Mesoamerican pottery analysis Kelsey Falter, Stephanie House, Sarah Kimball, Anna Gabrielle O Meara O

2 Introduction Short introduction into subject : How does PIXE work? Scientific method and technique Description of the goal of scientific investigation Results of scientific investigation Conclusion: Future of PIXE

3 What is PIXE? PIXE is a method which uses a proton current to analyze samples. The sample emits x-x rays due to the protons, which can then be used for artifact analysis by scientists.

4 Requirements for PIXE analysis 1. Atomic weight higher than twenty 2. Large dimensions, meaning medium and heavy sized atoms (Demortier,, 67) 3. Non-corroded or partially destroyed (Demortier( Demortier,, 72) 1. PIXE assumes the material in the sample is homogeneous (Demortier( Demortier, 74)

5 How PIXE works The accelerator creates a low level proton current (Demortier,, 72) This current makes contact with the sample, which has been placed by the accelerator, and causes the electrons to jump, creating x-x rays After the x-rays x appear, filters and foils make the results even clearer The final results will appear on a computer screen, ready to be examined by scientists

6 Results yield numerous lines Lines can be split into two types: K alpha lines and L alpha lines The screen also yields a background image called bremsstrahlung Scientists must take into account many factors when analyzing results Analyzing results

7 Results & Advantages Linear rule in peak areas Find stopping power and x-x ray absorption until they have reached a lower modification than statistical accuracy records Compare results Determine which elements are found within the sample PIXE is more sensitive than normal x-ray x fluorescence Can be performed at atmospheric pressure

8 Goal of scientific method The purpose of PIXE analyzation is to discover facts about archaeological objects that can help anthropologists, archaeologists, and art historians to discover more about a culture, civilization, or artist Decipher an artifact's date, origin, and authenticity.("pixe", ", 1) "The study of archaeological materials and objects from the ancient American civilizations gives rise to new knowledge about cultural and technological development, the use of materials, cultural relationships and their chronology."(demortier,, 67) Effective because it is non-destructive

9 What is the purpose? In one example The differences in pottery composition could indicate different techniques of preparing clay Cultural changes can begin to be deciphered through the analyzation of pottery.

10 Learning about relationships Compare murals from pre- hispanic archaeological sites and colonial convents Commonly used pigment in mesoamerican pottery and murals was Maya blue Particularly unique pigment because, "...it resists concentrated acids, alkalis and organic solvents." (Sanchez del Rio, 2) Learn more about the relationship between the indigenous people and the colonists

11 Application of PIXE on Mesoamerican Art Historical context of individual pieces Greater perspective on the aesthetic methods used in different ancient Latino cultures

12 Locating origin of obsidian Elemental structure of virtually all green obsidian pigments correspond directly with a source in Cerro de las Navajas Gray and black obsidian pigments are native to a more central Mexican area

13 PIXE and obsidian Ability to identify these regional characteristics helps classify differences in regional aesthetics and rarity Helps determine trade relationships between ancient cities

14 Future of PIXE analysis Opportunities to determine trade routes Example: Christopher Columbus and European trade routes