Study of experimental and numerical simulation of laser ablation in
stainless steel

Khalil, A. H.; Sreenivasan, Narasimhan

doi:10.1002/lapl.200510024

Cited by 34 publications

(18 citation statements)

References 8 publications

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“…The saturation in T e and N e at higher laser intensity for untreated and treated samples for SP and DP excitation may be due to plasma shielding, i.e., reflection and/or absorption of the laser photons by the plasma plume, which depends upon the plasma frequency. The prompt electrons released from Si target excite and ionize the ambient molecules, which give enhancement in the emission intensity of spectral lines especially in the DP configuration [46][47][48] and treated samples.…”

Section: Plasma Parametersmentioning

confidence: 99%

Chemical etching method assisted double-pulse LIBS for the analysis of silicon crystals

Khalil

2015

Appl. Phys. A

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Two Nd:YAG lasers working in pulsed modes are combined in the same direction (collinear arrangement) to focus on silicon (Si) crystals in reduced oxygen atmosphere (0.1 mbar) for double-pulse laser-induced breakdown spectroscopy (DP-LIBS) system. Silicon crystals of (100) and (111) orientations were investigated, and Si samples were measured either without prior treatment (''untreated'') or after fabrication of nano-pores (''treated''). Nano-pores are produced by metal coating and by chemical etching. DP-LIBS spectra were compared for different Si samples (untreated, treated, (100) and (111) orientations), for double-pulse (DP) (with 266 nm pulse followed by 1064 nm pulse) excitation and for different delay times (times between the excitation laser pulse and the detection ICCD gate); treatment by chemical etching has been studied as well. The intensity of the atomic line Si I at 288.16 nm was enhanced by a factor of about three by using the DP-LIBS signals as compared to the single-pulse (SP) signal which could increase the sensitivity of the LIBS technique. This study proved that an optimized value of the etching time of Si during etching by chemical processes and short delay times are required. Plasma parameters [the electron temperature (T e ) and the electron number density (N e )] were calculated from measured SP-and DP-LIBS spectra. The most important result of this study is the much higher DP-LIBS intensity observed on Si (100) as compared to Si (111) for measurements under the same experimental conditions. This study could provide important reference data for the design and optimization of DP-LIBS systems involved in plasma-facing components diagnostics.

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Section: Plasma Parametersmentioning

confidence: 99%

Chemical etching method assisted double-pulse LIBS for the analysis of silicon crystals

Khalil

2015

Appl. Phys. A

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“…The time profiles of the emission lines have maxima at different delay times τ 10...20 μs after a laser shot. This non-monotonic decay of the emission intensity could be due to a complex combination of the repopulation of the atomic Na states by collisional cascade (Civiš et al 2010) and the transfer processes in ablation products (Khalil & Sreenivasan 2005;Kawaguchi et al 2008).…”

Section: Methodsmentioning

confidence: 99%

Na I spectra in the 1.4–14 micron range: transitions and oscillator strengths involving f-, g-, and h-states

Civiš

Ferus

Kubelík

et al. 2012

A&A

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Context. Compared with the visible and ultraviolet ranges, fewer atomic and ionic lines are available in the infrared spectral region. Atlases of stellar spectra often provide only a short list of identified lines, and modern laboratory-based spectral features for wavelengths longer than 1 micron are not available for most elements. For the efficient use of the growing capabilities of infrared (IR) astronomy, detailed spectroscopical information on atomic line features in the IR region is needed. Aims. Parts of the infrared stellar (e.g., solar) spectra in the 1200-1800 cm −1 (5.6-8 μm) range have never been observed from the ground because of heavy contamination of the spectrum by telluric absorption lines. Such an infrared spectrum represents a great challenge for laboratory observations of new, unknown infrared atomic transitions involving the atomic levels with high orbital momentum and their comparison with the available spectra. Methods. The vapors of excited Na I atoms are produced during the ablation of the salt (sodium iodide, Na I) targets by a highrepetition rate (1.0 kHz) pulsed nanosecond ArF laser ExciStar S-Industrial V2.0 1000, pulse length 12 ns, λ = 193 nm, output energy of 15 mJ, fluence about 2-20 J/cm 2 inside a vacuum chamber (average pressure 10 −2 Torr). The time-resolved emission spectrum of the neutral atomic potassium (Na I) was recorded in the 700-7000 cm −1 region using the Fourier transform infrared spectroscopy technique with a resolution of 0.02 cm −1 . The f -values calculated in the quantum-defect theory approximation are presented for the transitions involving the reported Na I levels.Results. This study reports precision laboratory measurements for 26 Na I lines in the range of 700-7000 cm −1 (14-1.4 μm), including 20 lines not measured previously in the laboratory. This results in newly observed 7h, 6h, and 6g levels, and improved energy determination for ten previously known levels. The doublet structure of the 4f level has been observed for the first time. For transitions between the observed levels, we report calculated f -values that agree reasonably well with experiment. Conclusions. The recorded Na I line features agree with the data from the available solar spectrum atlases. The energy values of Na I 4s, 4p, 5p, 6p, 4f, 5f, and 5g levels extracted from our spectra have lower uncertainties as compared to the values reported several decades ago, but the latter values slightly differ from ours.

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“…Laser decontamination means the removal of radioactivity from the radioactively contaminated surface by the laser beam. Khalil et al [7] presented an experimental and theoretical study of pulse laser ablation of stainless steel target. Various parameters such as laser power, pulse duration, enthalpy and heat capacity were used.…”

Section: Introductionmentioning

confidence: 99%

A comparative study on the laser removal of Cs+ ion from type 304 stainless steel

Won

Baigalmaa

Moon

et al. 2010

Korean J. Chem. Eng.

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A Q-switched Nd:YAG laser with a 1,064 nm and 450 mJ/pulse was employed to study the cleaning characteristics of Type 304 stainless steel specimens artificially contaminated with Cs + ions. Before laser irradiation, the specimens were treated with KCl and KNO 3 , respectively. The relative atomic molar percent of Cs + ion on a metal surface was analyzed by EPMA. Before and after the laser irradiation, the morphology of the metal surfaces was investigated by SEM. The optimum laser fluence determined in the experimental range was 57.3 J/cm 2 . For all the test specimens, more than 95% of the Cs + ions were removed by the application of 40 laser shots at 57.3 J/cm 2 . Cs + ion removal efficiency was improved by the addition of nitrate ions to the contaminated metal surface. Surface temperature during the laser irradiation was calculated using Hertz-Knudsen equation to investigate the surface characteristics. A portion of particulates generated during the laser irradiation was found to accumulate around a crater of the specimen treated with the KCl solution. It was concluded that the ablated Cs + ions formed an oxide after thermal activation on the surface and deposited on a metal surface for the KCl system. The higher Cs + ion removal efficiency of the KNO 3 system was attributed to the decomposition of the nitrate ions at a relatively low temperature and the easy reaction of the Cs + ions with the oxygen generated from the decomposition of nitrate ions.

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Study of experimental and numerical simulation of laser ablation in stainless steel

Cited by 34 publications

References 8 publications

Chemical etching method assisted double-pulse LIBS for the analysis of silicon crystals

Chemical etching method assisted double-pulse LIBS for the analysis of silicon crystals

Na I spectra in the 1.4–14 micron range: transitions and oscillator strengths involving f-, g-, and h-states

A comparative study on the laser removal of Cs+ ion from type 304 stainless steel

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