Supervisor:

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Rutherford Backscattering Spectrometry (RBS)
2nd Summer School May 17, to June 6, 2010
University of JINR (DUBNA _ RUSSIA)
Supervisor Prof. A.P. Kobzev FLNP- JINR (Dubna,
Russia)
Prepared by Hani Negm Assistant Lecturer of
Physics Assiut University
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RBS

• RBS is an ion scattering technique that is used
  for the surface layer analysis of solids.
• A target is bombarded with ions at an energy in
  the MeV-range (0.5 4 MeV)
• The energy of the backscattered projectiles is
  recorded with an energy sensitive detector,
  typically a solid state detector.
• RBS allows the quantitative determination of the
  composition of a material and depth profiling of
  individual elements.

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RBS

• RBS is
• quantitative without the need for reference
  samples,
• nondestructive,
• has a good depth resolution of the order of
  several nm,
• and a very good sensitivity for heavy elements of
  the order of parts-per-million (ppm).

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RBS

• Chamber for RBS Method

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RBS

• If a particle of mass M1 is scattered in
  electrical field of nuclear of mass M2 at angle
  ?, its energy is K-part of initial energy E0.
  Applying the principle of conservation of energy
  and momentum, one can obtain next equation for
  kinematic factor K

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RBS
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RBS

• The yield of scattered particle is calculated
  using the differential scattering cross section
  which is given by Rutherfords formula

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RBS

• If the ion is scattered at the depth X, it will
  losses energy as well along the inward path ?Ein
  as outward path ?Eout

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RBS

• Energy loss depends on the atomic number both of
  incident ion and target atoms, their atomic
  density N and on energy of the incident ion. For
  the calculations of RBS spectra, usually is used
  such named stopping cross section e

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RBS

• the thickness of layers can calculate according
  to the energy width of the channel dE in the
  multichannel analyzer. The number of particles
  getting to the channel from Q incident particles
  is

H(E1) Q s(E,?) ?O dE/(S cosT1)
where ?O solid angle of the detector.
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RBS
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RBS
Possibilities of RBS Method
Element Ti Nb
Minimum Thickness, nm 30 10
Maximum Thickness, nm 1800 1500
Real Thickness, nm 264 169.5
Sensitivity, at/cm2 2x1016 1x1016
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THANK YOU FOR YOUR ATTENTION
negm_sci_at_aun.edu.eg