Analyses of Plasmas Produced by Laser Ablation of Fresh Aliments

2011 ◽  
Vol 227 ◽  
pp. 49-52 ◽  
Author(s):  
Sid Ahmed Beldjilali ◽  
Jörg Hermann ◽  
Tewfik Baba-Hamed ◽  
Ahmed Belasri

Detection and analysis of trace mineral elements in vegetables, and more generally in food by laser-induced breakdown spectroscopy (LIBS) promises applications with expected outcomes in nutrition quality. LIBS ensures contactless, real-time measurements of multielemental samples without any preparation of the samples surface. However, its application to analyses of aliments such as vegetables has one main drawback. Organic materials are strongly inhomogeneous and the physical properties that govern the processes of laser energy absorption, material ablation and plasma formation depend on a large number of parameters making calibration with standard samples impossible. This technique requires therefore a calibration-free approach that allows one to deduce the relative elemental concentrations from the intensities of spectral lines emitted from the laser-produced plasma. The main difficulty of such an approach is related to the temporal and spatial variation of the plasma properties. Therefore we have performed spectroscopic analysis of the plasma produced by Nd:Yag laser ablation of potato flesh and skin. The emission spectra recorded with an Echelle spectrometer with ICCD detector were compared to the spectral radiance computed for a plasma in local thermal equilibrium to deduce the mass fractions of the mineral elements.

2020 ◽  
Vol 1 (2) ◽  
pp. 5-8
Author(s):  
Komang Gde Suastika, Heri Suyanto, Gunarjo, Sadiana, Darmaji

Abstract - Laser-Induced Breakdown Spectroscopy (LIBS) is one method of atomic emission spectroscopy using laser ablation as an energy source. This method is used to characterize the type of amethysts that originally come from Sukamara, Central Kalimantan. The result of amethyst characterization can be used as a reference for claiming the natural wealth of the amethyst. The amethyst samples are directly taken from the amethyst mining field in the District Gem Amethyst and consist of four color variations: white, black, yellow, and purple. These samples were analyzed by LIBS, using laser energy of 120 mJ, delay time detection of 2 μs and accumulation of 3, with and without cleaning. The purpose of this study is to determine emission spectra characteristics, contained elements, and physical characteristics of each amethyst sample. The spectra show that the amethyst samples contain some elements such as Al, Ca, K, Fe, Gd, Ba, Si, Be, H, O, N, Cl and Pu with various emission intensities. The value of emission intensity corresponds to concentration of element in the sample. Hence, the characteristics of the amethysts are based on their concentration value. The element with the highest concentration in all samples is Si, which is related to the chemical formula of SiO2. The element with the lowest concentration in all samples is Ca that is found in black and yellow amethysts. The emission intensity of Fe element can distinguish between white, purple, and yellow amethyst. If Fe emission intensity is very low, it indicates yellow sample. Thus, we may conclude that LIBS is a method that can be used to characterize the amethyst samples.Key words: amethyst, impurity, laser-induced, breakdown spectroscopy, characteristic, gemstones


2019 ◽  
Vol 14 (31) ◽  
pp. 205-214
Author(s):  
Ali A-K. Hussain

In this work, the spectra for plasma glow produced by pulseNd:YAG laser (λ=532 and 1064nm) on Ag:Al alloy with same molarratio samples in distilled water were analyzed by studying the atomiclines compared with aluminum and silver strong standard lines. Theeffect of laser energies of the range 300 to 800 mJ on spectral lines,produced by laser ablation, were investigated using opticalspectroscopy. The electron temperature was found to be increasedfrom 1.698 to 1.899 eV, while the electron density decreased from2.247×1015 to 5.08×1014 cm-3 with increasing laser energy from 300to 800 mJ with wavelength of 1064 nm. The values of electrontemperature using second harmonic frequency are greater than of1064 nm, which increased from 2.405 to 2.444 eV, while the electrondensity decreased from 2.210×1015 to 1.516×1015 cm-3 withincreasing laser energy for the same energy range.


2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940022
Author(s):  
V. V. Kiris ◽  
A. V. Butsen ◽  
E. A. Ershov-Pavlov ◽  
M. I. Nedelko ◽  
A. A. Nevar

Composite Ag–Cu and Ni–C nanoparticles were synthesized by laser ablation and spark discharge in liquid, respectively. An amplification of the signal during laser induced breakdown spectroscopy was observed after deposition of the nanoparticles on the surface of an aluminum foil. The emission intensity of the laser plume increased from 2 to 20 times depending on the spectral lines used for the measurements. The intensity growth was higher for Ag–Cu nanoparticles.


2021 ◽  
Vol 9 ◽  
Author(s):  
Junxiao Wang ◽  
Yang Zhao ◽  
Lei Zhang ◽  
Shuqing Wang ◽  
Maogen Su ◽  
...  

Through the theoretical simulation and analysis of the whole process of laser ablating target and producing plasma with high spatio-temporal resolution, it is helpful for people to gain a more complete understanding of the ablation process of target and the evolution process of plasma parameters, which has an important guiding role for the improvement and optimization of laser ablation technology. Alloys are commonly used in daily life, but there are few researches on laser-induced alloy targets at present. Therefore, based on the thermal model of laser ablation and the two-dimensional axisymmetric multi-species hydrodynamic model, the process of laser ablating Al-Mg alloy under atmospheric pressure argon is theoretically simulated, and the ablation process of alloy target and the spatio-temporal evolution results of plasma parameters under different laser irradiances are compared. At high laser irradiance, the melt and evaporation depth, laser energy absorption and plasma characterization parameters are much greater than those at low laser irradiance, and the species energy distribution at different laser irradiance also presents different trends. In addition, the velocity of different species is calculated according to the position-time diagram of the maximum emission intensity, and they expand at a constant speed during the studied time. These results can provide some theoretical guidance for the early application of laser-induced breakdown spectroscopy in metallurgy.


2021 ◽  
Vol 51 (3) ◽  
Author(s):  
Hussein Salloom ◽  
Tagreed Hamad

In this work, laser-induced breakdown spectroscopy (LIBS) analysis is optimized for direct estimation of elemental composition, thermal conductivity and hardness for Ni-Cr-Nb alloys. These alloys were chosen with a variable elemental content of niobium and chromium. The influence of laser energy and shot numbers on measuring line intensity was investigated. Based on the ratio between two spectral lines, calibration curves were formed to estimate the element concentration and LIBS results were confirmed with related energy-dispersive X-ray spectroscopy (EDS) data. Hardness and thermal conductivity estimation using LIBS were done by measuring the ratio between two spectral lines, plasma excitation temperature and electron density for different samples. Semi-empirical formulas correlated hardness and thermal conductivity with plasma temperature were established.


Author(s):  
Baida M. AHMED ◽  
Shaimaa Hussein Abd MUSLIM ◽  
Muntadher Jawad KHOUDHAIR

The plasma spectroscopy analysis for Iron induced plasma was carried out using a Q-switched Nd: YAG pulsed laser system. The Laser wavelength was (1064) nm, Emission spectra were obtained using different energies in the range (600-900) mJ. Electron temperatures are evaluated at different laser peak powers from Boltzmann (-1/KBT) and Suha equation, also, the electron densities are deduced using stark broadening. A limited number of suitable Fe lines are detected and the plasma parameters are discussed. The Electron temperatures of (Fe) are measured and were found to be in the range of (1.8–1.88) eV. It is observed in the case of iron the electron temperature is proportional with laser energy and the highest peak in (Fe) arrive at (55396.52). Keywords: Iron Plasma, Laser-Induced Plasma Spectroscopy, Plasma Parameters.


2019 ◽  
Vol 73 (4) ◽  
pp. 380-386 ◽  
Author(s):  
Sheng Niu ◽  
Lijuan Zheng ◽  
Abdul Qayyum Khan ◽  
Heping Zeng

We demonstrated a unique method for the detection of heavy metals, such as Ni, Cr, and Cd, at trace level in aqueous solutions by laser induced breakdown spectroscopy (LIBS) enriched by aluminum oxide (Al2O3) nanoparticles (NP) adsorption. Al2O3 NPs were used for the sample phase transformation and heavy metals pre-concentration because of its excellent adsorption capacity and sparse spectral lines. The influence of laser wavelength and laser irradiance on the signal intensity was investigated. With 45 mL solutions used for enrichment and adsorption, limits of detection obtained for Ni, Cr, and Cd were 9.61, 8.49, and 71.6 μg/L under 532 nm laser ablation, and 22.5, 20.4, and 83.8 μg/L under 1064 nm laser ablation, respectively. The relative standard deviations of all elements were about 12% or 13%. Moreover, Al2O3 NPs adsorption enrichment of target elements was verified and the detection sensitivity was improved by increasing the amount of sample solutions.


2020 ◽  
pp. 000370282097304
Author(s):  
Amal A. Khedr ◽  
Mahmoud A. Sliem ◽  
Mohamed Abdel-Harith

In the present work, nanoparticle-enhanced laser-induced breakdown spectroscopy was used to analyze an aluminum alloy. Although LIBS has numerous advantages, it suffers from low sensitivity and low detection limits compared to other spectrochemical analytical methods. However, using gold nanoparticles helps to overcome such drawbacks and enhances the LIBS sensitivity in analyzing aluminum alloy in the current work. Aluminum was the major element in the analyzed samples (99.9%), while magnesium (Mg) was the minor element (0.1%). The spread of gold nanoparticles onto the Al alloy and using a laser with different pulse energies were exploited to enhance the Al alloy spectral lines. The results showed that Au NPs successfully improved the alloy spectral lines intensity by eight times, which could be useful for detecting many trace elements in higher matrix alloys. Under the assumption of local thermodynamic equilibrium, the Boltzmann plot was used to calculate the plasma temperature. Besides, the electron density was calculated using Mg and H lines at Mg(I) at 285.2 nm and Hα(I) at 656.2 nm, respectively. Three-dimensional contour mapping and color fill images contributed to understanding the behavior of the involved effects.


1998 ◽  
Vol 538 ◽  
Author(s):  
V. Zhigilei ◽  
Barbara J. Garrison

AbstractLaser ablation of organic solids is a complex collective phenomenon that includes processes occurring at different length and time scales. A mesoscopic breathing sphere model developed recently for molecular dynamics simulation of laser ablation and damage of organic solids has significantly expanded the length-scale (up to hundreds of nanometers) and the time-scale (up to nanoseconds) of the simulations. The laser induced buildup of a high pressure within the absorbing volume and generation of the pressure waves propagating from the absorption region poses an additional challenge for molecular-level simulation. A new dynamic boundary condition is developed to minimize the effects of the reflection of the wave from the boundary of the computational cell. The boundary condition accounts for the laser induced pressure wave propagation as well as the direct laser energy deposition in the boundary region.


1990 ◽  
Vol 191 ◽  
Author(s):  
Michael E. Geusic ◽  
Alan F. Stewart ◽  
Larry R. Pederson ◽  
William J. Weber ◽  
Kenneth R. Marken ◽  
...  

ABSTRACTExcimer laser ablation with an in situ heat treatment was used to prepare high quality superconducting YBa2Cu3O7−x thin films on (100)-SrTiO3 and (100)-LaAlO3 substrates. A pulsed excimer laser (XeCl; 308 nm) was used to ablate a rotating, bulk YBa2Cu3O7−x target at a laser energy density of 2–3 J/cm2. Based on four-probe dc resistance measurements, the films exhibited superconducting transition temperatures (Tc, midpoint) of 88 and 87K with 2K (90–10%) transition widths for SrTiO3 and LaAlO3, respectively. Transport critical current densities (Jc) measured at 77K were 2 × 106 and 1 × 106 A/cm2 in zero field for SrTiO3 and LaAlO3, respectively. X-ray diffraction (XRD) analysis showed the films to be highly oriented, with the c-axis perpendicular to the substrate surface.


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