بسم الله الرحمن الرحيم. Compositional Study of Different Currency Coins Using Non-Destructive Laser Induced Breakdown Spectroscopy. 2 nd SASC Muharram, 1425 Jeddah, KSA. Zain Yamani, Ph.D. Physics Department KFUPM. Presentation plan. Introduction: What is LIBS?
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Compositional Study of Different Currency Coins Using Non-Destructive Laser Induced Breakdown Spectroscopy
Zain Yamani, Ph.D.
LIBS: Laser Induced Breakdown Spectroscopy
LIBS is an analytical method by which one can determine (qualitatively and quantitatively) the elemental composition of solid, liquid or gas samples.
This is not to say that there are no complications in LIBS.
Of course, there are!
(applications, from the literature)
Rotating sample holder
LIBS for coin compositional determination
PDA ~ optical multi-channel analyzer
With a Photo-Diode Array (PDA), one can simultaneously detect the intensity of many “different” wavelengths.
10% iron in KBr (calibration pellet)
Data: 4000-4400 Å
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!!
There are similarities between the three spectra; for example, all have Fe peaks (e.g., @ 4228 Å.
The game token does not contain copper (e.g. @ 4180, 4275 & 4377 Å).
The real currencies do contain copper!!
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.
The Euro coin does not have the 4201 & 4401Å Ni peaks.
The game token has more iron and nickel than the other (real) currencies.
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).
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.
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.
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.
Is LIBS absolutely NDT?
Also, check Applied Optics vol 42 (30), Oct. 2003 (theme issue)
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.
Thank you for your attention
Power [energy per pulse & pulse width] dependence
Atmosphere type and pressure
Shot to shot energy fluctuation
Depends on photon energy [esp. plasma absorption]