1. Ion beam Analysis Joele Mira from UWC and iThemba LABS Tinyiko Maluleke from US Supervisor: Dr. Alexander Kobzev Dr. Alexander Kobzev

2. 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

3. 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.

4. 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,

5. 10/10/2008SA-JINR Summer School 20085 Experimental setup for RBS

6. 10/10/2008SA-JINR Summer School 20086 RBS spectrum ElementConc. At(%) Pb0.05 Ru0.5 Br0.05 Fe0.59 Ca0.26 P0.5 Al1.0 O12.90 C84.06 6

7. 10/10/2008SA-JINR Summer School 20087

8. 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.

9. 10/10/2008SA-JINR Summer School 20089 Experimental setup

10. 10/10/2008SA-JINR Summer School 200810 RBS spectrum RBS SPECTRUM 10

11. 10/10/2008SA-JINR Summer School 200811 ERDA spectrum ERDA Spectrum 11

12. 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.

13. 10/10/2008SA-JINR Summer School 200813 Experimental setup for RBS and PIXE 13

14. 10/10/2008SA-JINR Summer School 200814 RBS and PIXE RBS Spectrum 14

15. 10/10/2008SA-JINR Summer School 200815 PIXE PIXE Spectrum 15

16. 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

17. 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.

18. 10/10/2008SA-JINR Summer School 200818 Thanks for your attention!!