Ion beam Analysis

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Ion beam Analysis

• Joele Mira
• from UWC and iThemba LABS
• Tinyiko Maluleke
• from US
• Supervisor
• Dr. Alexander Kobzev

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Contents

• Descriptions of Van de Graaf
• Rutherford back-scattering (RBS)
• RBS and Elastic recoil detection (ERD)
• RBS and Proton induced X-ray emission (PIXE)
• Conclusion

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VAN DE GRAAFF ACCELERATOR

• The EG-5 accelerator, accelerate ions to energy
  between 0.9-3.5 MeV
• Beam intensity of 30µA for H and 10 µA for He.
• Energy spread of 0.5 keV.
• Energy precision of 2 keV.
• 6 beam lines.

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Introduction to RBS

• The use of RBS is to provide information on
  concentration vs depth for heavy element in a
  light material.
• A beam of 2-3 MeV He ions are directed at
  different angles on a sample surface.
• The ion loses energy due to collision with
  electrons.
• The ion will scatter elastically with the atomic
  nucleus and lead to a kinematic factor K,

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Experimental setup for RBS
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RBS spectrum
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Elastic Recoil Detection (ERD)

• ERD is a complimentary technique to RBS
• It is used to measure concentration of H atoms in
  the thin layers, and in the near surface region
  of material.
• The incident beam is directed at a grazing angle
  onto the sample surface.
• The recoiling atoms are ejected and detected at
  forward angle.
• A thin foil is placed in front of the detector to
  stop elastically scattered incident ion beam and
  all atoms with mass heavier than the beam.

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Experimental setup
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RBS spectrum
RBS SPECTRUM
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ERDA spectrum

• ERDA Spectrum

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Proton Induced X-ray Emission (PIXE)

• Occurs when a sample is bombarded with the beam,
  the proton interact with the electrons in the
  atoms of the sample, creating an inner shell
  vacancy
• The X-ray is emitted when an electron from outer
  shell fills the hole left by an electron.
• The energy of the X-rays emitted are
  characteristic of the element from which they
  originate.
• The number of emitted X-rays is proportional to
  the amount of the corresponding element within
  the sample.

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Experimental setup for RBS and PIXE
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RBS and PIXE

• RBS Spectrum

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PIXE

• PIXE Spectrum

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PIXE
Elements content concentrations in aerosol
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Conclusion

• The use of ion beam analysis is non-destructive,
  high accuracy and easy to interpret the
  experimental results.
• The use of these models allow the determination
  of different elements from Hydrogen to heavy
  elements concentrated in samples.
• It also allow the analysis of very thin sample of
  about 10 nm.
• Ion beam analysis is applied in various fields
  such as microelectronics, environmental
  monitoring etc.

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Thanks for your attention!!