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Ion beam Analysis. Joele Mira from UWC and iThemba LABS Tinyiko Maluleke from US Supervisor: Dr. Alexander Kobzev. 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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Ion beam Analysis Joele Mira from UWC and iThemba LABS Tinyiko Maluleke from US Supervisor: Dr. Alexander Kobzev
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 SA-JINR Summer School 2008
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. SA-JINR Summer School 2008
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, SA-JINR Summer School 2008
Experimental setup for RBS SA-JINR Summer School 2008
RBS spectrum SA-JINR Summer School 2008 6
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. SA-JINR Summer School 2008
Experimental setup SA-JINR Summer School 2008
RBS spectrum RBS SPECTRUM SA-JINR Summer School 2008 10
ERDA spectrum ERDA Spectrum SA-JINR Summer School 2008 11
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. SA-JINR Summer School 2008
Experimental setup for RBS and PIXE SA-JINR Summer School 2008 13
RBS and PIXE RBS Spectrum SA-JINR Summer School 2008 14
PIXE PIXE Spectrum SA-JINR Summer School 2008 15
PIXE Elements content & concentrations in aerosol SA-JINR Summer School 2008 16
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. SA-JINR Summer School 2008
Thanks for your attention!! SA-JINR Summer School 2008