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
Characteristic X-Rays
Characteristic X-Rays
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
PIXE Spectrum
PIXE Spectrum
Conclusions
• The elements found in the meteorites were :
Ca
Ti
Cr
Fe
Ni
Cu
Zn
Ga
As
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