ion beam analysis
DESCRIPTION
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. - PowerPoint PPT PresentationTRANSCRIPT
Ion beam AnalysisIon beam AnalysisIon beam AnalysisIon beam AnalysisJoele MiraJoele Mira
from UWC and iThemba LABSfrom UWC and iThemba LABS
Tinyiko MalulekeTinyiko Maluleke
from USfrom US
Supervisor: Supervisor:
Dr. Alexander Kobzev Dr. Alexander Kobzev
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ContentsContents
Descriptions of Van de GraafRutherford 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 ACCELERATORVAN 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 RBSIntroduction 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,
2
12
12
12
122
0
12
cos)sin(
MM
MMM
E
Em
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Experimental setup for RBSExperimental setup for RBS
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RBS spectrumRBS spectrum
Element Conc. At(%)
Pb 0.05
Ru 0.5
Br 0.05
Fe 0.59
Ca 0.26
P 0.5
Al 1.0
O 12.90
C 84.06
6
400 600 800 10000
50
100
150
Br
Ru
Fe
Ca
P
Al
O
Bac
ksca
tterin
g Y
ield
Channel
Pb
EHe
= 2.3MeV
170
Thickness = 12x1015 Atoms/cm2
0 200 400 600 800 1000
0
50
100
150
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Elastic Recoil Detection (ERD)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 setupExperimental setup
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RBS spectrumRBS spectrum
RBS SPECTRUM10
100 200 300 400 500 600 7000
500
1000
1500
2000
2500
3000
RB
S Y
ield
Channel number
100 200 300 400 500 600 700
0
500
1000
1500
2000
2500
3000
Thickness = 2.5X1018cm-2
H = 32%C = 18%O = 20%Si = 30%
C
O
Si
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ERDA spectrumERDA spectrum
ERDA Spectrum
100 200 300 400 5000
200
400
600
800
ER
D Y
ield
Channel
Thickness = 2.5X1018cm-2
H = 32%C = 18%O = 20%Si = 30%
11
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Proton Induced X-ray Emission (PIXE)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 PIXEExperimental setup for RBS and PIXE
13
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RBS and PIXERBS and PIXE
RBS Spectrum
550 600 650 700 750 8000
500
1000
1500
2000
2500
3000
3500
4000B
ack
scatt
eri
ng y
ield
Channel number
Aerosol E
p=2.005 MeV
=1350
S
Na AlSi
CaFe
F
O
NC
14
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PIXEPIXE
PIXE Spectrum15
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PIXEPIXE 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 Sr 0.0006 PIXE
S 0.2
RBS Zr 0.005
PIXE
Cl 0.01 PIXE Ba 0.01 PIXE
Elements content & concentrations in aerosol 16
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Conclusion 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!!Thanks for your attention!!