Ion Beam Analysis

Ion Beam Analysis
Dolly Langa
Physics Department, University of Pretoria, South Africa
Blane Lomberg
Physics Department, University of the Western Cape, South Africa
Project Supervisor: Prof A.P. Kobzev
Frank Laboratory of Neutron Physics,
Joint Institute for Nuclear Research,
Dubna, Russia
AIM OF PROJECT
Analysis of contents and depth distribution of different
elements in the near surface layers of solids using
• Rutherford Backscattering Spectrometry (RBS)
• Elastic Recoil Detection (ERD)
• Particle Induced X-ray Emission (PIXE)
OUTLINE
1. AIM OF PROJECT
2. VAN DER GRAAFF ACCELERATOR
3. PRINCIPLE OF ION BEAM ANALYSIS USED
4. RESULTS AND DISCUSSION
5. CONCLUSION
VAN DE GRAAFF ACCELERATOR
Van de Graaff Accelerator Parameters at JINR
• Produces the beams of helium ions and
protons with energy in regions 0.9-3.5 MeV
• Helium intensity less than 10 A and
proton intensity up to 30 A.
• Energy spread less than 500 eV
• The accelerator belt moves at 20 m/s
• The accelerator is placed in a tank
under pressure of 10 atmospheres of dry
nitrogen.
•The accelerator EG-5 has six beam
lines.
PRINCIPLE OF ION BEAM ANALYSIS USED Conti..
Rutherford Backscattering Spectrometry (RBS)
 m2


2
2
E1  ( M 2  M 1 sin )  M 1 cos  



E0 
M 2  M1


1
2
2
Counts
RESULTS AND DISCUSSION
RBS spectrum for the sample with the Fe and Ti layers on Si
substrate, with Ti layer containing Oxygen.
Energy [keV]
200
400
600
800
1000
1200
1400
Calibration:
1600
4,000
BR727.DAT
Simulated
EHe = 2.035 MeV
 = 100
 = 1700
3,600
3,200
Calibration offset = 35.72 keV
Energy per channel = 1.8782 keV/ch
Fe
2,800
Oxygen
2,400
Thickness:
2,000
Si Substrate
Ti
Fe = 76 nm
1,600
Ti = 62 nm
1,200
800
Concentrations in Ti layer:
400
Ti = 30 at %
0
80
120
160
200
240
280
320
360
400
440
480
520
Channel
560
600
640
680
720
760
800
840
880
O = 70 at %
RBS spectrum for the sample with the Ge and Si multi-layers on Si
substrate
Energy [keV]
100
200
300
400
500
600
700
800
2,000
M259.DAT
Simulated
EHe = 1 MeV
1,800
Ge
 = 300
 = 200
1,600
 = 1700
1,400
Counts
1,200
1,000
Si substrate
800
Si
600
400
200
0
120
160
200
240
280
320
360
400
440
480
Channel
520
560
600
640
680
720
760
800
PRINCIPLE OF ION BEAM ANALYSIS USED
Rutherford Backscattering Spectrometry (RBS) and Elastic Recoil
Detection (ERD) setup
RBS and ERD spectra
Thickness: (C) = 170 nm
Thickness (O) = 20 nm
Si = 26 at %
Si = 70 at %
H = 40 at %
H = 20 at %
C = 34 at %
O = 10 at %
Energy [keV]
Energy [keV]
300
400
500
600
700
800
900
1000
1100
1200
1300
1400
1500
0
1600
200
300
400
500
600
700
800
900
1000
BR784.nra
Simulated
EHe = 2.297 MeV
Thickness (H) = 190 nm
 = 750
550
5,000
C
500
 = 750
450
Counts
O
3,500
3,000
1300
BE235.nra
Simulated
600
4,000
1200
650
5,500
4,500
1100
700
6,500
6,000
100
 = 300
400
350
300
2,500
2,000
EHe = 2.297 MeV
1,500
 = 750
200
150
 = 300
1,000
100
 = 1350
500
0
150
250
Si
50
0
200
250
300
350
400
450
500
Channel
550
600
650
700
750
800
850
0
50
100
150
200
250
300
350
400
450
500
550
Channel
600
650
700
750
800
850
900
950
1,000
PRINCIPLE OF ION BEAM ANALYSIS USED Conti..
Particle Induce X-ray Emission (PIXE)
PIXE
RBS
Aerosol analysis by PIXE & RBS
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
CONCLUSION
• These methods are non-destructive techniques to study materials
• The used methods allow the determination of depth distribution and
concentration from hydrogen to heavy elements.
• The spectra calculations and model comparisons was executed in
SIMNRA software tool, in which good agreement was achieved for
RBS and ERD experiments.
• Furthermore, the depth resolution is done near to few nm range for
these methods.
• The sensitivity for heavy elements is of the order 1014 atoms/cm2
THANK YOU

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