Presentation on theme: "Ion beam Analysis Joele Mira from UWC and iThemba LABS Tinyiko Maluleke from US Supervisor: Dr. Alexander Kobzev Dr. Alexander Kobzev."— Presentation transcript:
Ion beam Analysis Joele Mira from UWC and iThemba LABS Tinyiko Maluleke from US Supervisor: Dr. Alexander Kobzev Dr. Alexander Kobzev
10/10/2008SA-JINR Summer School 20082 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
10/10/2008SA-JINR Summer School 20083 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.
10/10/2008SA-JINR Summer School 20084 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,
10/10/2008SA-JINR Summer School 20085 Experimental setup for RBS
10/10/2008SA-JINR Summer School 20088 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.
10/10/2008SA-JINR Summer School 20089 Experimental setup
10/10/2008SA-JINR Summer School 200810 RBS spectrum RBS SPECTRUM 10
10/10/2008SA-JINR Summer School 200811 ERDA spectrum ERDA Spectrum 11
10/10/2008SA-JINR Summer School 200812 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.
10/10/2008SA-JINR Summer School 200813 Experimental setup for RBS and PIXE 13
10/10/2008SA-JINR Summer School 200814 RBS and PIXE RBS Spectrum 14
10/10/2008SA-JINR Summer School 200815 PIXE PIXE Spectrum 15
10/10/2008SA-JINR Summer School 200816 PIXE Element Concen. At. % Method Element Concen. At. % Method C 41 RBS K 0.1 PIXE N 20.5 RBS Ca 0.53 RBS O 28 RBS Mn 0.007 PIXE F 2.6 RBS Fe 0.14 RBS Na 2.5 RBS Cu 0.002 PIXE Mg 1.3 RBS Zn 0.01 PIXE Al 1.3 RBS As 0.001 PIXE Si 1.8 PIXE Sr0.0006 PIXE S 0.2 RBS Zr 0.005 PIXE Cl 0.01 PIXE Ba 0.01 PIXE Elements content & concentrations in aerosol 16
10/10/2008SA-JINR Summer School 200817 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.
10/10/2008SA-JINR Summer School 200818 Thanks for your attention!!