Electron number density measurements using laser-induced breakdown spectroscopy of ionized nitrogen spectral lines

In this work, the Stark broadening parameters (widths and shifts) of the 2203.5 Å and 4386.5 Å Pb(II) spectral lines have been investigated and measured in laser-induced breakdown spectroscopy (LIBS), using a lead sample (99.999% purity). A Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser operating at its fundamental wavelength (10 640 Å), generating pulses of 290 mJ, 7 ns of duration, and a repeat frequency of 20 Hz, has been used for the ablation of said lead sample in vacuum and in a controlled argon atmosphere. A study to understand the expansion dynamics of the lead produced plasma was performed. The spectra have been obtained and measured at different time delays of the plasma evolution in the range of 0.15–9 μs, at which the temperature and electron number density are in the ranges of 28 200–8000 K and 1.3 × 1017 to 3 × 1015 cm−3, respectively. A graphical representation of the evolution of temperature and electron number density versus 0.3 to 6.5 μs delay from the laser pulse is presented. The important effect of the different environment where the plasma expands has been pointed out. Local thermodynamic equilibrium conditions have been checked. The obtained results of the Stark widths and shifts at the different temperatures and densities of electrons have been compared with the limited data available in the literature. This study aims to obtain more accurate values for these parameters and also to establish regularities and similarities for said parameters.

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Spatial confinement effects employed by metallic blocker and Ar gas pressures on laser-induced breakdown spectroscopy and surface modifications of laser-irradiated Mg

Laser and Particle Beams ◽

10.1017/s0263034617000210 ◽

2017 ◽

Vol 35 (2) ◽

pp. 313-325 ◽

Cited By ~ 3

Author(s):

A. Hayat ◽

S. Bashir ◽

M. S. Rafique ◽

R. Ahmed ◽

M. Akram ◽

...

Keyword(s):

Electron Temperature ◽

Electron Number Density ◽

Number Density ◽

Confinement Effects ◽

Electron Number ◽

Plasma Parameters ◽

Spatial Confinement ◽

Breakdown Spectroscopy ◽

Laser Induced Breakdown ◽

Ar Gas

AbstractSpatial confinement effects on plasma parameters and surface morphology of laser-ablated Mg are studied by introducing a metallic blocker as well as argon (Ar) gas at different pressures. Nd: YAG laser at various fluences ranging from 7 to 28 J/cm2 was employed to generate Mg plasma. Confinement effects offered by metallic blocker are investigated by placing the blocker at different distances of 6, 8, and 10 mm from the target surface; whereas spatial confinement offered by environmental gas is explored under four different pressures of 5, 10, 20, and 50 Torr. Laser-induced breakdown spectroscopy analysis revealed that both plasma parameters, that is, excitation temperature and electron number density initially are strongly dependent upon both pressures of environmental gases and distances of blockers. The maximum electron temperature of Mg plasma is achieved at Ar gas pressure of 20 Torr, whereas maximum electron number density is achieved at 50 Torr. It is also observed that spatial confinement offered by metallic blocker is responsible for the significant enhancement of both electron temperature and electron number density of Mg plasma. Maximum values of electron temperature and electron number density without blocker are 8335 K and 2.4 × 1016 cm−3, respectively, whereas these values are enhanced to 12,200 K and 4 × 1016 cm−3 in the presence of blocker. Physical mechanisms responsible for the enhancement of Mg plasma parameters are plasma compression, confinement and pronounced collisional excitations due to reflection of shock waves. Scanning electron microscope analysis was performed to explore the surface morphology of laser-ablated Mg. It reveals the formation of ripples and channels that become more distinct in the presence of blocker due to plasma confinement. The optimum combination of blocker distance, fluence and Ar pressure can identify the suitable conditions for defining the role of plasma parameters for surface structuring.

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Gold Nanoparticle-Enhanced Laser-Induced Breakdown Spectroscopy and Three-Dimensional Contour Imaging of an Aluminum Alloy

Applied Spectroscopy ◽

10.1177/0003702820973040 ◽

2020 ◽

pp. 000370282097304

Author(s):

Amal A. Khedr ◽

Mahmoud A. Sliem ◽

Mohamed Abdel-Harith

Keyword(s):

Gold Nanoparticles ◽

Aluminum Alloy ◽

Three Dimensional ◽

Plasma Temperature ◽

Spectral Lines ◽

Laser Induced Breakdown Spectroscopy ◽

Al Alloy ◽

Boltzmann Plot ◽

Breakdown Spectroscopy ◽

Laser Induced Breakdown

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.

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Magnetic field effect on laser-induced breakdown spectroscopy and surface modifications of germanium at various fluences

Laser and Particle Beams ◽

10.1017/s0263034617000039 ◽

2017 ◽

Vol 35 (1) ◽

pp. 159-169 ◽

Cited By ~ 11

Author(s):

H. Iftikhar ◽

S. Bashir ◽

A. Dawood ◽

M. Akram ◽

A. Hayat ◽

...

Keyword(s):

Magnetic Field ◽

Electron Temperature ◽

Surface Modifications ◽

Laser Induced Breakdown Spectroscopy ◽

Excitation Temperature ◽

Number Density ◽

Plasma Parameters ◽

Breakdown Spectroscopy ◽

Laser Induced Breakdown ◽

The Magnetic Field

AbstractThe effect of the transverse magnetic field on laser-induced breakdown spectroscopy and surface modifications of germanium (Ge) has been investigated at various fluences. Ge targets were exposed to Nd: YAG laser pulses (1064 nm, 10 ns, 1 Hz) at different fluences ranging from 3 to 25.6 J/cm2 to generate Ge plasma under argon environment at a pressure of 50 Torr. The magnetic field of strength 0.45 Tesla perpendicular to the direction of plasma expansion was employed by using two permanent magnets. The emission spectra of laser-induced Ge plasma was detected by the laser-induced breakdown spectroscopy system. The electron temperature and number density of Ge plasma are evaluated by using the Boltzmann plot and stark broadening methods, respectively. The variations in emission intensity, electron temperature (Te), and number density (ne) of Germanium plasma are explored at various fluences, with and without employment of the magnetic field. It is observed that the magnetic field is responsible for significant enhancement of both excitation temperature and number density at all fluences. It is revealed that an excitation temperature increases from Te,max,without B = 16,190 to Te,max,with B = 20,123 K. Similarly, the two times enhancement in the electron density is observed from ne,max,without B = 2 × 1018 to ne,max,with B = 4 × 1018 cm−3. The overall enhancement in Ge plasma parameters in the presence of the magnetic field is attributed to the Joule heating effect and adiabatic compression. With increasing fluence both plasma parameters increase and achieve their maxima at a fluence of 12.8 J/cm2 and then decrease. In order to correlate the plasma parameters with surface modification, scanning electron microscope analysis of irradiated Ge was performed. Droplets and cones are formed for both cases. However, the growth of ridges and distinctness of features is more pronounced in case of the absence of the magnetic field; whereas surface structures become more diffusive in the presence of the magnetic field.

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Nanoparticle-Enhanced Laser Induced Breakdown Spectroscopy Using Copper–Silver and Nickel–Carbon Nanocomposites on Aluminium

International Journal of Nanoscience ◽

10.1142/s0219581x19400222 ◽

2019 ◽

Vol 18 (03n04) ◽

pp. 1940022

Author(s):

V. V. Kiris ◽

A. V. Butsen ◽

E. A. Ershov-Pavlov ◽

M. I. Nedelko ◽

A. A. Nevar

Keyword(s):

Laser Ablation ◽

Emission Intensity ◽

Aluminum Foil ◽

Spectral Lines ◽

Laser Induced Breakdown Spectroscopy ◽

Cu Nanoparticles ◽

Laser Plume ◽

Carbon Nanocomposites ◽

Breakdown Spectroscopy ◽

Laser Induced Breakdown

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.

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