Post on 24-Feb-2016
description
Compositional Study of Different Currency Coins Using Non-Destructive Laser Induced Breakdown Spectroscopy
2nd SASC
Muharram, 1425Jeddah, KSA
Zain Yamani, Ph.D.Physics Department
KFUPM
الرحيم الرحمن الله بسم
Presentation planPresentation plan
1. Introduction: What is LIBS?
2. Different physical methods for material analysis.
3. What is special about LIBS?
4. Compositional determination of coins using LIBS:
a- Experimental set-up
b- Results
c- Conclusions
5. Concluding remarks
LIBS: Laser Induced Breakdown Spectroscopy
IntroductionIntroduction
LIBS is an analytical method by which one can determine (qualitatively and quantitatively) the elemental composition of solid, liquid or gas samples.
LIBS focused laser pulses vaporize, atomize and excite the sample plasma emission collect, disperse and analyze light atomic spectral lines determine the
elemental composition
What other methods are used for elemental analysisWhat other methods are used for elemental analysis
How does LIBS compare with other analytical methods?How does LIBS compare with other analytical methods?
Different types of samples
Little sample preparation
No (chemical) waste
Micro-LIBS
Portability
Rapid
NDT
This is not to say that there are no complications in LIBS.
Of course, there are!
What is LIBS used for?What is LIBS used for?
(applications, from the literature)(applications, from the literature)
Environmental monitoring to measure soil contamination (Zolotovitskaya et al., 1997)
Detect toxic metals (Yamamoto et al., 1996; Buckley et al., 2000)
Study the chemical compositions in liquids (Yueh et al., 2002; Samek et al., 2000)
Study the chemical compositions in polymers (Sattmann et al., 1998)
In forensics and military applications (Kincade, 2003)Biomedical studies of bones and teethArt restoration (or conservation), by analyzing pigments and/or precious and ancient metals (Anzano et al., 2002)
LIBS for coin compositional determinationLIBS for coin compositional determination
Experimental set-up
Nd-YAG
3rd harmonic
prism
dichroic mirror
personal computer
monochromator
mirror
collecting lens
Rotating sample holder
sample
PDA
Movie
grating
mirror
mirror 1024 diodes
PDA ~ optical multi-channel analyzer
With a Photo-Diode Array (PDA), one can simultaneously detect the intensity
of many “different” wavelengths.
LIBS for coin compositional determinationLIBS for coin compositional determination
Experimental Results
1. PDA Calibration
2. Apply LIBS to coins
a. Check repeatability
b. Look for coin signatures
c. Reliability (same results in different regions!!)
d. NDT
LIBS for coin compositional determinationLIBS for coin compositional determination
4000 4100 4200 4300 44000
5000
10000
15000
20000
25000
30000
4047
.119
8740
65.5
9985
4074
.419
92
4122
.719
7341
37.8
3984
4149
.179
69
4192
.859
8642
07.5
6006
4235
.279
78
4260
.060
0642
70.9
7998
4281
.899
9 4319
.279
7843
37.7
5977
4396
.979
98
4418
.819
8244
29.3
1982In
tens
ity (A
.U.)
Wavelength (A)
10% iron in KBr (calibration pellet)
Fe I 4045.8 4000Fe I 4063.6 1500Fe I 4071.7 1200Fe I 4143.9 800Br II 4223.9 1000Fe I 4260.5 800Fe I 4271.8 1200Fe I 4282.4 1200Fe I 4307.9 1200Fe I 4325.8 1500Br I 4365.1 2000Br II 4365.6 1000Fe I 4375.9 800Fe I 4383.5 3000Fe I 4404.8 1200Br I 4425.1 1500
http://physics.nist.gov/cgi-bin/AtData/lines_form
Data: 4000-4400 Å
0
5000
10000
15000
20000
25000
4000 4050 4100 4150 4200 4250
Wavelength (A)
Inte
nsity
(A.U
.)
LIBS spectra for (solid) one side of a 25 Fils Bahrain coin and (dashed) the other side of the same coin.
Notice how the spectra are almost identical!!
0
5000
10000
15000
20000
25000
30000
35000
40000
4000 4100 4200 4300 4400
Wavelength (A)
Inte
nsity
(A.U
.)
LIBS spectra for (solid) a 10-Hallalah Saudi coin, (dashed) 20 cent Euro coin and (dotted) a game token, in the 4000-4425 Å region.
There are similarities between the three spectra; for example, all have Fe peaks (e.g., @ 4228 Å.
The game token has more iron and nickel than the other (real) currencies.
The game token does not contain copper (e.g. @ 4180, 4275 & 4377 Å). The real currencies do contain copper!!
The Euro coin does not have the 4201 & 4401Å Ni peaks.
LIBS spectra for (solid) a 10-Hallalah Saudi coin, (dashed) 20 cent Euro coin and (dotted) a game token, in the 5250-5550 Å region.
Common iron peaks (e.g. 5270
Å).
The game token does not contain copper. The
real currencies do
contain copper!! (e.g.
5293 Å).The Euro
coin does not have the Ni peaks. (e.g.
5475 Å).
The results are consistent with
that of the 4000-4400 Å region.
It is difficult to distinguish between Saudi and Bahrani coins. They probably have very similar elemental composition.
0
5000
10000
15000
20000
25000
30000
35000
40000
5250 5300 5350 5400 5450 5500 5550
Wavelength (A)
Inte
nsity
(A.U
.)
Photographs of the four coins used in the experiments (a) before and (b) after 30 seconds of laser irradiation. The coins show no apparent destruction due to LIBS.
(a) (b)
Is LIBS absolutely NDT?
LIBS as NDT?
LIBS for coin compositional determinationLIBS for coin compositional determination
Conclusions LIBS spectra are repeatable.
LIBS gives consistent/ reliable results in different regions.
Coins have iron.
Game token has no copper.
20 cent Euro coin is nickel-free.
We can distinguish between “different” currencies using LIBS.
The spectra of the Saudi 10-Hallalah and the Bahrain 25 Fils are very similar.
At the macroscopic level, LIBS procedure can be NDT.
Good general references on LIBSGood general references on LIBS
Also, check Applied Optics vol 42 (30), Oct. 2003 (theme issue)
1. LIBS is a very useful technique for the elemental analysis of material.
2. LIBS can be used for fast, precise, on-line, non-destructive testing of coins.
3. LIBS can be beneficial for the identification of currency and also for quality control in coins production.
4. LIBS applies to different types of material and is conducive to interdisciplinary research, a concept very beneficial for academic research in Saudi Arabia.
Concluding RemarksConcluding Remarks
5. Further study:
i. both qualitative and quantitative.
ii. different photon energy and laser pulse energy.
iii. effect of optical alignment of beam with the sample, and optical alignment of beam with the detection system.
iv. increase sensitivity by using gated ICCD.
v. study the effects of delayed time.
6. I would be happy to work with collaborators.
Thank you for your attention
The support of King Fahd University of Petroleum and Minerals is gratefully acknowledged.
The encouragement of professor M.A. Gondal, as well as the assistance of Mr. Abdullah Baziyad and Mr. Abdullah Al-Zahrani, is deeply appreciated.
I am thankful to Mr. Fuad Enaya for his help in preparing the presentation.
AcknowledgementAcknowledgement
Sample matrix
Morphology
Power [energy per pulse & pulse width] dependence
Atmosphere type and pressure
Shot to shot energy fluctuation
Depends on photon energy [esp. plasma absorption]
Complications in Using LIBS