TY - CONF A1 - Gornushkin, Igor B. T1 - LIBS as an analytical method-facts, figures and high hopes T2 - Winter Plasma Conference 2014 CY - Amelia Island, USA DA - 2014-03-01 PY - 2014 AN - OPUS4-32125 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Data processing and modeling T2 - LIBS 2014 CY - Beijing, China DA - 2014-09-09 PY - 2014 AN - OPUS4-32128 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Standardless analysis of steel slags via plasma modeling T2 - LIBS 2014 CY - Beijing, China DA - 2014-09-06 PY - 2014 AN - OPUS4-32131 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Porizka, Pavel A1 - Demidov, Alexandr A1 - Kaiser, J. A1 - Keivanian, J. A1 - Gornushkin, Igor B. A1 - Panne, Ulrich A1 - Riedel, Jens T1 - Laser-induced breakdown spectroscopy for in situ qualitative and quantitative analysis of mineral ores N2 - In this work, the potential of laser-induced breakdown spectroscopy (LIBS) for discrimination and analysis of geological materials was examined. The research was focused on classification of mineral ores using their LIBS spectra prior to quantitative determination of copper. Quantitative analysis is not a trivial task in LIBS measurement because intensities of emission lines in laser-induced plasmas (LIP) are strongly affected by the sample matrix (matrix effect). To circumvent this effect, typically matrix-matched standards are used to obtain matrix-dependent calibration curves. If the sample set consists of a mixture of different matrices, even in this approach, the corresponding matrix has to be known prior to the downstream data analysis. For this categorization, the multielemental character of LIBS spectra can be of help. In this contribution, a principal component analysis (PCA) was employed on the measured data set to discriminate individual rocks as individual matrices against each other according to their overall elemental composition. Twenty-seven igneous rock samples were analyzed in the form of fine dust, classified and subsequently quantitatively analyzed. Two different LIBS setups in two laboratories were used to prove the reproducibility of classification and quantification. A superposition of partial calibration plots constructed from the individual clustered data displayed a large improvement in precision and accuracy compared to the calibration plot constructed from all ore samples. The classification of mineral samples with complex matrices can thus be recommended prior to LIBS system calibration and quantitative analysis. KW - Laser-induced breakdown spectroscopy KW - LIBS KW - Chemometrics KW - Principal component analysis KW - Geochemical analysis PY - 2014 DO - https://doi.org/10.1016/j.sab.2014.08.027 SN - 0584-8547 SN - 0038-6987 VL - 101 SP - 155 EP - 163 PB - Elsevier CY - Amsterdam AN - OPUS4-32588 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eschlböck-Fuchs, S. A1 - Demidov, Alexander A1 - Gornushkin, Igor B. A1 - Schmid, Thomas A1 - Rössler, R. A1 - Huber, N. A1 - Panne, Ulrich A1 - Pedarnig, J. D. T1 - Tomography of homogenized laser-induced plasma by Radon transform technique N2 - Tomography of a laser-induced plasma in air is performed by inverse Radon transform of angle-resolved plasma images. Plasmas were induced by single laser pulses (SP), double pulses (DP) in collinear geometry, and by a combination of single laser pulses with pulsed arc discharges (SP-AD). Images of plasmas on metallurgical steel slags were taken at delay times suitable for calibration-free laser-induced breakdown spectroscopy (CFLIBS). Delays ranged from few microseconds for SP and DP up to tens of microseconds for SP-AD excitation. The white-light and the spectrally resolved emissivity ε(x,y,z) was reconstructed for the three plasma excitation schemes. The electron number density Ne(x,y,z) and plasma temperature Te(x,y,z) were determined from Mg and Mn emission lines in reconstructed spectra employing the Saha-Boltzmann plot method. The SP plasma revealed strongly inhomogeneous emissivity and plasma temperature. Re-excitation of plasma by a second laser pulse (DP) and by an arc discharge (SP-AD) homogenized the plasma and reduced the spatial variation of ε and Te. The homogenization of a plasma is a promising approach to increase the accuracy of calibration-free LIBS analysis of complex materials. KW - Plasma tomography KW - Laser induced plasma KW - Radon transform technique KW - Laser induced breakdown spectroscopy (LIBS) KW - Steel slag KW - Calibration-free analysis PY - 2016 DO - https://doi.org/10.1016/j.sab.2016.07.007 VL - 123 SP - 59 EP - 67 PB - Elsevier B.V. AN - OPUS4-37452 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Shabanov, Sergej V. A1 - Gornushkin, Igor B. T1 - Absorption tomography of laser induced plasmas N2 - An emission tomography of laser-induced plasmas employed in the laser induced breakdown spectroscopy (LIBS) requires signal integration times in a microsecond range during which the LIBS plasma cannot be considered stationary. Consequently, the use of the data for reconstructing the plasma properties under the assumption that the latter does not change significantly during the integration time leads to inaccurate results. To reduce the integration time, it is proposed to measure a plasma absorption in parallel rays using a scanning rectangular aperture whose dimension Δ along the scanning direction is about a characteristic size of plasma plumes (Δ ~ 1 cm) and the other dimension Δp is of the order of a uniformity length of plasma parameters (Δp ~ 10 µm). The aperture is moved step by step along the scanning direction and the total energy of photons coming through the aperture is measured during time T at each position of the aperture. Owing to the large size of the aperture, the integration time T is reduced by a factor ~ Δp/Δ. A numerical data processing is proposed to restore the spatial resolution of the plasma absorption along the scanning direction. It is determined by the scanning step Δs ≤ Δp. Another advantage of the proposed procedure is that inexpensive linear CCD or non-discrete (PMT, photodiode) detectors can be used instead of costly 2-dimensional detectors. KW - Plasma tomography KW - Laser induced plasma PY - 2012 DO - https://doi.org/10.1016/j.jqsrt.2011.12.016 SN - 0022-4073 VL - 113 IS - 7 SP - 518 EP - 523 PB - Pergamon Press CY - Oxford [u.a.] AN - OPUS4-25823 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Xue, Boyang A1 - You, Yi A1 - Gornushkin, Igor B. A1 - Zheng, R. A1 - Riedel, Jens T1 - High-throughput underwater elemental analysis by μJ-laser-induced breakdown spectroscopy at kHz repetition rates: part I, ultrasound-enhanced optical emission spectroscopy towards application perspectives N2 - In recent years, laser-induced breakdown spectroscopy (LIBS) has gained significant attention as a means for simple elemental analyses. The suitability of LIBS for contactless analysis allows it to be a perfect candidate for underwater applications. While the majority of LIBS systems still rely upon sub-kHz pulsed lasers, this contribution introduces 10s-kHz low pulse-energy lasers into underwater LIBS to improve the throughput and statistical validity. Interestingly, the spectral component significantly changed above a critical laser repetition-rate threshold. Spectral lines of atomic hydrogen and oxygen stemming from water become visible beyond a ∼10 kHz repetition rate. This observation suggests a different plasma dynamic compared to low repetition rates. When the pulse-to-pulse interval becomes sufficiently short, a cumulative effect begins to be significant. Apparently, the new phenomena occur on a timescale corresponding to a threshold rate of ∼10 kHz, i.e. ∼100 μs. Analytically, the high repetition rates result in improved statistical validity and throughput. More plasma events per unit time allowed the use of low efficiency Echelle spectrometers without compromising on the analytical performance. Meanwhile, the presence of H I and O I out of the water (as the matrix) also offers internal standardization in underwater elemental analysis. Since the laser fluence was on the lower edge of the plasma threshold, an additional ultrasound source was introduced to induce external perturbation, which significantly improved the plasma formation stability. A huge advantage of LIBS is the possibility of detecting almost all elements within a sample simultaneously. Throughout the periodic table, chlorine is one of the most challenging elements. Consequently, Ca2+ and Na+ were used as samples to demonstrate the capability of this high repetition-rate LIBS platform. As an ambitious benchmark for our system, chlorine detection in water was also discussed. KW - High repetition rate KW - Laser-induced breakdown spectroscopy PY - 2020 DO - https://doi.org/10.1039/D0JA00290A VL - 35 IS - 12 SP - 2901 EP - 2911 PB - The Royal Society of Chemistry AN - OPUS4-51564 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gottlieb, Cassian A1 - Gojani, Ardian A1 - Völker, Tobias A1 - Günther, Tobias A1 - Gornushkin, Igor B. A1 - Wilsch, Gerd A1 - Günster, Jens T1 - Investigation of grain sizes in cement-based materials and their influence on laser-induced plasmas by shadowgraphy and plasma imaging N2 - The effect of particle grain sizes in different cement-based mixtures on the laser-induced plasma evolution is studied using two experimental methods: (i) temporal and spatial evolution of the laser-induced shock wave is investigated using shadowgraphy and two-dimensional plasma imaging, and (ii) temporal and spatial distribution of elements in the plasma is investigated using two-dimensional spectral imaging. This study is motivated by the interest in applying laser-induced breakdown spectroscopy (LIBS) for chemical analysis of concrete, and subsequently obtain information related to damage assessment of structures like bridges and parking decks. The distribution of grain sizes is of major interest in civil engineering as for making concrete different aggregate grain sizes defined by a sieving curve (64mm to 0.125 mm) are needed. Aggregates up to a size of 180 μm can be excluded from the data set, therefore only the amount of small aggregates with a grain size below 180 μm must be considered with LIBS. All components of the concrete with a grain size smaller than 0.125mm are related to the flour grain content. Tested samples consisted of dry and hardened cement paste (water-cement ratio w/z=0.5), which served as a reference. Aggregate mixtures were made by adding flour grains (size 40 μm) and silica fume (size 0.1 μm) in different ratios to cement: 10%, 30%, 50% and 60%, all combined to the remaining percentage of dry or hydrated cement. The visualization results show that a dependance in the evolution of the plasma as a function of sample grain size can be detected only in the initial stages of the plasma formation, that is, at the initial 3 μs of the plasma life. Spectral information reveals the elemental distribution of the silicon and calcium in plasma, in both neutral and ionized form. Here also, a significant effect is observed in the first 1 μs of the plasma lifetime. KW - LIBS KW - Cement-based materials KW - Particle size KW - Shadowgraphy KW - Plasma imaging PY - 2020 DO - https://doi.org/10.1016/j.sab.2020.105772 VL - 165 SP - 105772 PB - Elsevier B.V. AN - OPUS4-50319 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Shabanov, Sergej V. A1 - Sennikov, P. G. T1 - Equilibrium Chemistry in BCl3–H2–Ar Plasma N2 - The approach, which was developed earlier for modeling chemical reactions in laser induced plasmas, is applied to radio-frequency discharge plasmas. The model is based on the assumption that all ionization processes and chemical reactions are at local thermodynamic equilibrium. A chemical composition of an argon-hydrogen plasma with an Addition of boron trichloride is studied as a function of plasma temperature and mole ratio H2∕BCl3. It is established that more than twenty simple and composite molecules and ions can be formed in the course of chemical reactions. The results are compared with those obtained earlier by means of another equilibrium model that uses ab-initio quantum chemical computations of thermochemical and kinetic data and a 0D thermochemical quilibrium solver. KW - Modeling chemical reactions KW - Plasma physics KW - Plasma enhanced chemical vapor deposition PY - 2019 DO - https://doi.org/10.1007/s11090-019-09985-6 VL - 39 IS - 4 SP - 1087 EP - 1102 PB - Springer AN - OPUS4-47817 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Laser induced plasma as a chemical reactor: how feasible? N2 - A goal of this work is to apply the model, which was initially developed for laser induced plasmas, to plasmas used in chemical reactors, in particular, the inductively-coupled-RF discharge plasma. The model predicts equilibrium chemical compositions of reaction mixtures as functions of plasma temperature and stoichiometry of reactants. The mixtures investigated are BCl3/H2/Ar and BF3/H2/Ar where Ar serves as the plasma-forming gas and H2 as a binding agent which binds the active species Cl and F and Cl- and F-containing intermediates to produce gaseous B and its condensate. An additional goal is to obtain information about intermediate reaction products for different ratios of BCl3/H2 and BF3/H2 and at different temperatures and different Ar flow rates. Also, chemical reactions in laser induced plasmas (LIPs) created on calcium hydrate and calcium carbonate targets in argon are modeled. The results are compared with those obtained by means of the equilibrium model based on the minimization of Gibbs free energy. T2 - 1st workshop on Tandem LIBS/LA-ICP-MS CY - BAM, Berlin, Adlershof DA - 18.11.2019 KW - LIBS KW - Laser induced plasma KW - Plasma modeling KW - Plasma chemical reactor PY - 2019 AN - OPUS4-49776 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Molecule formation in calcium carbonate and calcium hydroxide libs plasmas: model and experiment N2 - Analysis of calcium hydrate and calcium carbonate samples and their mixtures is important for archeology, anthropology, and geology. Laser-induced plasma spectroscopy (LIBS) is a suitable tool for such the analysis as it allows for in- and on-line real time chemical assays. LIBS is inherently a technique for atomic analysis; however, since recently, it is also used for molecular analysis. The information attained by the latter is mainly related to “secondary” chemistry that deals with re-association of atoms and ions into molecules at long delay times (≥10 μs) after the initial breakdown. Even though the direct information about the initial molecular content in the target may be lost, the molecular analysis by LIBS can still be useful to assess the composition of samples. In this work, chemical reactions in laser induced plasmas (LIPs) created on calcium hydrate and calcium carbonate targets in argon are modeled and compared to experiment. The model is based on the assumption that all ionization processes and chemical reactions are at local thermodynamic equilibrium. A chemical composition of argon-calcium-oxygen and argon-calcium-hydrogen plasmas is studied as a function of plasma temperature and pressure. It is established that more than twenty simple and composite molecules and ions can be formed in the course of chemical reactions. The results are compared with those obtained by means of the equilibrium model based on the minimization of Gibbs free energy. T2 - SciX 2019 CY - Palm Springs, USA DA - 13.10.2019 KW - Plasma diagnostics KW - LIBS KW - Laser induced plasma KW - Plasma modeling PY - 2019 AN - OPUS4-49775 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Modeling equilibrium chemistry in laser induced plasmas and plasma chemical reactors N2 - A goal of this work is to apply the model, which was initially developed for laser induced plasmas, to plasmas used in chemical reactors, in particular, the inductively-coupled-RF discharge plasma. The model predicts equilibrium chemical compositions of reaction mixtures as functions of plasma temperature and stoichiometry of reactants. The mixtures investigated are BCl3/H2/Ar and BF3/H2/Ar where Ar serves as the plasma-forming gas and H2 as a binding agent which binds the active species Cl and F and Cl- and F-containing intermediates to produce gaseous B and its condensate. An additional goal is to obtain information about intermediate reaction products for different ratios of BCl3/H2 and BF3/H2 and at different temperatures and different Ar flow rates. Also, chemical reactions in laser induced plasmas (LIPs) created on calcium hydrate and calcium carbonate targets in argon are modeled. The results are compared with those obtained by means of the equilibrium model based on the minimization of Gibbs free energy. T2 - SciX 2019 CY - Palm Springs, USA DA - 13.10.2019 KW - LIBS KW - Laser induced plasma KW - Plasma modeling PY - 2019 AN - OPUS4-49774 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Dell’Aglio, M. A1 - Motto-Ros, V. A1 - Pelascini, F. A1 - De Giacomo, A. T1 - Investigation on the material in the plasma phase by high temporally and spectrally resolved emission imaging during Pulsed Laser Ablation (PLAL) in Liquid for NPs production and consequent considerations on NPs formation N2 - In this paper experimental temperature and density maps of the laser induced plasma in water during Pulsed Laser ablation in Liquid (PLAL) for the production of metallic nanoparticles (NPs) has been determined. A detection system based on the simultaneous acquisition of two emission images at 515 and 410 nm has been constructed and the obtained images have been processed simultaneously by imaging software. The results of the data analysis show a variation of the temperature between 4000 and 7000 K over the plasma volume. Moreover, by the study of the temperature distribution and of the number densities along the plasma expansion axis it is possible to observe the condensation zone of the plasma where NPs can be formed. Finally, the time associated to the electron processes is estimated and the plasma charging effect on NPs is demonstrated. The set of observations retrieved from these experiments suggests the importance of the plasma phase for the growth of NPs and the necessity of considering the spatial distribution of plasma parameters for the understanding of one of the most important issues of the PLAL process, that is the source of solid material in the plasma phase. KW - LIBS KW - Laser induced plasma KW - Plasma modeling KW - Plasma diagnostics KW - Nanoparticle formation PY - 2019 DO - https://doi.org/10.1088/1361-6595/ab369b VL - 28 IS - 8 SP - Article Number: 085017 PB - IOP Publishing AN - OPUS4-48753 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Optimization and detailed spectroscopic characterization of an improved SH-LIBS setup N2 - The spatial heterodyne detection principle has a great potential in spectroscopy. It has an optical setup similar to that of a Michelson interferometer, with the mirrors replaced by diffraction gratings positioned at fixed, equal distances from the beamsplitter and are slightly tilted. The resulting interference pattern is recorded by a digital camera and the spectrum is recovered by using Fourier transformation. Although SHS was initially developed for astronomical and satellite-based atmospheric measurements, but in recent years it has been started to be applied in other branches of spectroscopy too. Recently the area of laser-induced breakdown spectroscopy (LIBS) has also discovered the potential of SHS. The main appeal of SHS detection in LIBS includes the compactness and robustness of the setup (in view of field applications) and the flexibility to optimize the setup for either high sensitivity or for high resolution, which can be benficially exploited in applications like stand-off measurements, quantitative analysis with isotope resolution, etc. In the present work, we have improved and further optimized our initial LIBS-SHS setup described in a previous conference. By using optical simulations, we have modelled the light transmission efficiency, instrumental function and imaging properties of the system. We significantly improved and automated the spectral and image data processing sequence. The optimizations carried out resulted in an improved spectral resolution and repeatability, a lower spectral background and the elimination of the central line artifact originating from the Fourier transformation procedure. A detailed characterization of the LIBS spectroscopy performance (e.g. resolution, spectral coverage, tuning range, linearity, etc.), including a comparison with that of a LIBS setup based on a conventional dispersion CCD spectrometer was also performed. T2 - European Winter Conference on Plasma Spectrochemistry (EWSPS-2019) CY - Pau, France DA - 03.02.2019 KW - SHS KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Spatial heterodyne spectrometer PY - 2019 AN - OPUS4-48047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Laser induced Plasma: Modeling and diagnostics N2 - Laser-induced plasmas are widely used in many areas of science and technology; examples include spectrochemical analysis, thin film deposition, material processing, and even jet propulsion. Several topics will be addressed. First, general phenomenology of laser-induced plasmas will be discussed. Then, a chemical model will be presented based on a coupled solution of Navier-Stokes, state, radiative transfer, material transport, and chemical (Guldberg-Waage) equations. Results of computer simulations for several chemical systems will be shown and compared to experimental observations obtained by optical imaging, spectroscopy, and tomography. The latter diagnostic tools will also be briefly discussed. T2 - Lecture at the Dept of Chemistry of Czeged University (Hungary) on 31.05.2019 CY - Czeged, Hungary DA - 31.05.2019 KW - Plasma KW - LIBS KW - Plasma modeling PY - 2019 AN - OPUS4-48188 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Several approaches to calibration-free LIBS: Advantages and pitfalls N2 - An overview of calibration-free laser induced breakdown spectroscopy (CF LIBS) methods is presented. Advantages and pitfalls of these methods are critically discussed. T2 - Workshop of the Spectrochemical Working Committee (SWC) of the Hungarian Academy of Sciences CY - Budapest, Hungary DA - 05.06.2019 KW - Calibration-free LIBS KW - CF LIBS algorithms PY - 2019 AN - OPUS4-48189 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Equilibrium chemistry of boron halides in plasma chemical reactors N2 - High purity halides of III-VI group elements, especially chloride and fluorides, are used in gas phase technologies for obtaining high purity materials and coatings. The reduction of halides in hydrogen-halide mixtures can be achieved in various discharge plasmas, e.g. inductively coupled, ark, and even laser-induced plasmas. Existing models of such plasmas are not sufficiently accurate to predict a yield of the targeted compounds and to describe the plasma processes involved in formation of these compounds. Besides, a construction of costly plasma-chemical reactors can be alleviated by the prior modeling of plasma processes that may occur in such reactors. A goal of this work is to extend the model, which was initially developed for laser induced Plasmas, to plasmas used in chemical reactors, in particular, the inductively-coupled-RF discharge Plasma. The model predicts equilibrium chemical compositions of reaction mixtures as functions of plasma temperature and stoichiometry of reactants. The mixtures investigated are BCl3/H2/Ar and BF3/H2/Ar where Ar serves as the plasma-forming gas and H2 as a binding agent which binds the active species Cl and F and Cl- and F-containing intermediates to produce gaseous B and its condensate. An additional goal is to obtain information about intermediate reaction products for different ratios of BCl3/H2 and BF3/H2 and at different temperatures and different Ar flow rates. It is found that the desired components B and B2 appear at appreciable concentrations of >0.1% and ~0.01% respectively only at temperatures above 3000 K. It is also established that the effect of charged species on the reaction products is miniscule for temperatures below 5000 K. The expected yield of boron as a function of the original mole fraction H2/BCl3 and H2/BF3 is calculated. The mole fractions are varied in the range 0.1-1000 and the temperature in the range 1000-10000 K. It is shown that the yield of boron increases with increasing the molar ratio H2/BCl3 and H2/BF3 up to ~100 in the temperature range 2000-5000 K. At higher temperatures, T>5000 K, the boron concentration reaches its maximum and does not depend on the concentration of hydrogen; all molecules dissociate and chemical reactions proceed only between charged particles (mostly elemental ions) and electrons. The calculated plasma parameters and composition are compared with experimental data obtained by optical emission spectroscopy. The calculated plasma temperature and electron density are shown to be in good agreement with the measured ones. T2 - European Winter Conference on Plasma Spectrochemistry (EWSPS-2019) CY - Pau, France DA - 03.02.2019 KW - Chemical reactors KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics PY - 2019 AN - OPUS4-47541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Modeling chemistry in laser-induced and other types of plasmas N2 - A goal of this work is to extend the model, which was initially developed for laser induced plasmas, to plasmas used in chemical reactors, in particular, the inductively-coupled-RF discharge plasma. The model predicts equilibrium chemical compositions of reaction mixtures as functions of plasma temperature and stoichiometry of reactants. The mixtures investigated are BCl3/H2/Ar and BF3/H2/Ar where Ar serves as the plasma-forming gas and H2 as a binding agent which binds the active species Cl and F and Cl- and F-containing intermediates to produce gaseous B and its condensate. An additional goal is to obtain information about intermediate reaction products for different ratios of BCl3/H2 and BF3/H2 and at different temperatures and different Ar flow rates. It is found that the desired components B and B2 appear at appreciable concentrations of >0.1% and ~0.01% respectively only at temperatures above 3000 K. It is also established that the effect of charged species on the reaction products is miniscule for temperatures below 5000 K. The expected yield of boron as a function of the original mole fraction H2/BCl3 and H2/BF3 is calculated. The mole fractions are varied in the range 0.1-1000 and the temperature in the range 1000-10000 K. It is shown that the yield of boron increases with increasing the molar ratio H2/BCl3 and H2/BF3 up to ~100 in the temperature range 2000-5000 K. At higher temperatures, T>5000 K, the boron concentration reaches its maximum and does not depend on the concentration of hydrogen; all molecules dissociate and chemical reactions proceed only between charged particles (mostly elemental ions) and electrons. The calculated plasma parameters and composition are compared with experimental data obtained by optical emission spectroscopy. The calculated plasma temperature and electron density are shown to be in good agreement with the measured ones. T2 - Workshop on Laser and Plasmas Applications CY - Bari, Italy DA - 04.03.2019 KW - Plasma KW - LIBS KW - Plasma modeling PY - 2019 AN - OPUS4-47545 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gojani, Ardian A1 - Palásti, David J. A1 - Paul, Andrea A1 - Galbács, G. A1 - Gornushkin, Igor B. T1 - Analysis and classification of liquid samples by spatial heterodyne spectroscopy N2 - Spatial heterodyne spectroscopy (SHS) is used for quantitative analysis and classification of liquid samples. SHS is a version of a Michelson interferometer with no moving parts and with diffraction gratings in place of mirrors. The instrument converts frequency-resolved information into spatially resolved one and records it in the form of interferograms. The back-extraction of spectral information is done by the Fast Fourier transform. A SHS instrument is constructed with the resolving power 5000 and spectral range 522 - 593 nm. Two original technical solutions are used as compared to previous SHS instruments: the use of a high frequency diode pumped solid state (DPSS) laser for excitation of Raman spectra and a microscope-based collection system. Raman spectra are excited at 532 nm at the repetition rate 80 kHz. Raman shifts between 330 cm-1 and 1600 cm-1 are measured. A new application of SHS is demonstrated: for the first time it is used for quantitative Raman analysis to determine concentrations of cyclohexane in isopropanol and glycerol in water. Two calibration strategies are employed: univariate based on the construction of a calibration plot and multivariate based on partial least square regression (PLSR). The detection limits for both cyclohexane in isopropanol and glycerol in water are at a 0.5 mass% level. In addition to the Raman-SHS chemical analysis, classification of industrial oils (biodiesel, poly(1-decene), gasoline, heavy oil IFO380, polybutenes, and lubricant) is performed using their Raman-fluorescence spectra and principal component analysis (PCA). The oils are easily discriminated as they show distinct non-overlapping patterns in the space of principal components. KW - Spectroscopy KW - Atomic KW - Laser induced breakdown KW - Lasers PY - 2019 DO - https://doi.org/10.1177/0003702819863847 SN - 1943-3530 VL - 73 IS - 12 SP - 1409 EP - 1419 PB - Sage AN - OPUS4-48599 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Model of stimulated emission in aluminum laser-induced plasma produced by resonance pumping N2 - Stimulated emission observed experimentally in aluminum laser induced plasma is modeled via a kinetic approach. The simulated emission at several cascade transitions is created by a pump laser guided through the plasma at several microseconds after its creation and tuned in resonance with the strong transition at 266 nm. A two-dimensional space-time collisional radiative plasma model explains the creation of the population inversion and lasing at wavelengths 2.1 μm and 396.1 nm. The population inversion for lasing at 2.1 μm is created by depopulation of the ground state and population of the upper state via absorption of resonant radiation at 266 nm. The population inversion for lasing at 396.1 nm occurs during the laser pulse via the decay of the population of the pumped upper state to the lasing state via cascade transitions driven optically and by collisions. The model predicts that the population inversion and corresponding gain may reach high values even at moderate pump energies of several μJ per pulse. The efficiency of lasing at 2.1 μm and 396.1 nm is estimated to be on the order of a percent of laser pump energy. The polarization effect that the pump radiation at 266 nm imposes on the stimulated emission at 396.1 nm is discussed. The calculated results are favorably compared to experiment. T2 - FLAMN, June 30- July 4 2019 CY - St. Petersburg, Russia DA - 30.06.2019 KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics PY - 2019 AN - OPUS4-48598 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gornushkin, Igor B. T1 - Calibration-free LIBS of steel samples N2 - An improved algorithm for calibration-free laser induced breakdown spectroscopy (CF LIBS) is presented which includes several novel features in comparison with previously proposed similar algorithms. In particular, it allows using spectral lines with arbitrary optical thickness for the construction of Saha-Boltzmann plots, retrieves the absorption path length (plasma diameter) directly from a spectrum, replaces the Lorentzian line profile function by the Voigt function, and allows for self-absorption correction using pre-calculated and tabulated data rather than approximating functions. The tabulated data embody the solutions of the radiative transfer equation for numerous combinations of optical thicknesses and line widths. The algorithm is used to analyze 100 low alloy steel spectra. T2 - 20.06.2019 LTB workshop on LIBS analysis of steel CY - Berlin, LTB, Germany DA - 20.06.2019 KW - Laser induced plasma KW - LIBS KW - Plasma modeling KW - Plasma diagnostics KW - Chemical reactors PY - 2019 AN - OPUS4-48600 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -