Detection of trace elements in meteorites using PIXE Presented by: Sasha dos-Santos
Goals To determine the chemical composition of several meteorites To estimate the concentration of chemicals in PPM (parts per million)
Particle Induced X-Ray Emission Spectrometry A method of determining the chemical composition of a substance Has been in use since the 1970s Used in fields such as astrophysics, medicine, and environmental science
Characteristic X-Rays
The energy of the X-Ray is equal to the energy difference between the two orbitals This energy is characteristic of the element involved
Experimental Setup Van de Graaff Accelerator - this is the ion beam source
Experimental Setup Analyzing Magnet - Selects particles based on charge and mass
Experimental Setup PIXE Chamber - up to five samples can be placed in the chamber at a time
Experimental Setup Si-Li Drifted Detector - detects X-Rays and sends input to a multichannel analyzer
RobWin Used for Spectral Analysis Mathematically models background radiation (noise) Finds peaks that are not clearly visible
RobWin
PIXE Spectrum
Conclusions The elements found in the meteorites were : CaTiCr FeNiCu Zn GaAs
Conclusions Next step is to use a process called spin coating to produce thin film samples Then use thin film standards to determine chemical concentrations in the order of micrograms / sq. cm.
The End