TY - JOUR A1 - Müller, Maike A1 - Gornushkin, Igor B. A1 - Florek, S. A1 - Mory, D. A1 - Panne, Ulrich T1 - Approach to Detection in Laser-Induced Breakdown Spectroscopy JF - Analytical chemistry N2 - Gated detection with intensified detectors, e.g., ICCDs, is today the accepted approach for detection of plasma emission in laser-induced breakdown spectroscopy (LIBS). However, these systems are more cost-intensive and less robust than nonintensified CCDs. The objective of this paper is to compare, both theoretically and experimentally, the performance of an intensified (ICCD) and nonintensified (CCD) detectors for detection of plasma emission in LIBS. The CCD is used in combination with a mechanical chopper, which blocks the early continuum radiation from the plasma. The detectors are attached sequentially to an echelle spectrometer under the same experimental conditions. The laser plasma is induced on a series of steel samples under atmospheric conditions. Our results indicate that there is no substantial difference in the performance of the CCD and ICCD. Signal-to-noise ratios and limits of detection achieved with the CCD for Si, Ni, Cr, Mo, Cu, and V in steel are comparable or even better than those obtained with the ICCD. This result is further confirmed by simulation of the plasma emission signal and the corresponding response of the detectors in the limit of quantum (photon) noise. KW - LIBS KW - Detektorvergleich KW - ICCD CCD PY - 2007 DO - https://doi.org/10.1021/ac0621470 SN - 0003-2700 SN - 1520-6882 VL - 79 IS - 12 SP - 4419 EP - 4426 PB - American Chemical Society CY - Washington, DC AN - OPUS4-15044 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Panne, Ulrich A1 - Winefordner, J. D. T1 - Linear correlation for identification of materials by laser induced breakdown spectroscopy: Improvement via spectral filtering and masking JF - Spectrochimica acta B N2 - The purpose of this work is to improve the performance of a linear correlation method used for material identification in laser induced breakdown spectroscopy. The improved correlation procedure is proposed based on the selection and use of only essential spectral information and ignoring empty spectral fragments. The method is tested on glass samples of forensic interest. The 100% identification capability of the new method is demonstrated in contrast to the traditional approach where the identification rate falls below 100% for many samples. KW - Correlation analysis KW - Linear correlation KW - Material identification KW - Laser induced plasma KW - LIBS PY - 2009 DO - https://doi.org/10.1016/j.sab.2009.07.038 SN - 0584-8547 SN - 0038-6987 VL - 64 IS - 10 SP - 1040 EP - 1047 PB - Elsevier CY - Amsterdam AN - OPUS4-20621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Höhse, Marek A1 - Mory, D. A1 - Florek, S. A1 - Weritz, Friederike A1 - Gornushkin, Igor B. A1 - Panne, Ulrich T1 - A combined laser-induced breakdown and Raman spectroscopy Echelle system for elemental and molecular microanalysis JF - Spectrochimica acta B N2 - Raman and laser-induced breakdown spectroscopy is integrated into a single system for molecular and elemental microanalyses. Both analyses are performed on the same ~ 0.002 mm² sample spot allowing the assessment of sample heterogeneity on a micrometric scale through mapping and scanning. The core of the spectrometer system is a novel high resolution dual arm Echelle spectrograph utilized for both techniques. In contrast to scanning Raman spectroscopy systems, the Echelle-Raman spectrograph provides a high resolution spectrum in a broad spectral range of 200-6000 cm- 1 without moving the dispersive element. The system displays comparable or better sensitivity and spectral resolution in comparison to a state-of-the-art scanning Raman microscope and allows short analysis times for both Raman and laser induced breakdown spectroscopy. The laser-induced breakdown spectroscopy performance of the system is characterized by ppm detection limits, high spectral resolving power (15,000), and broad spectral range (290-945 nm). The capability of the system is demonstrated with the mapping of heterogeneous mineral samples and layer by layer analysis of pigments revealing the advantages of combining the techniques in a single unified set-up. KW - LIBS KW - Raman KW - Echelle KW - Laser-induced breakdown spectroscopy KW - Hyphenated technique PY - 2009 DO - https://doi.org/10.1016/j.sab.2009.09.004 SN - 0584-8547 SN - 0038-6987 VL - 64 IS - 11-12 SP - 1219 EP - 1227 PB - Elsevier CY - Amsterdam AN - OPUS4-20493 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Shabanov, Sergej V. A1 - Merk, Sven A1 - Tognoni, E. A1 - Panne, Ulrich T1 - Effects of non-uniformity of laser induced plasma on plasma temperature and concentrations determined by the Boltzmann plot method: implications from plasma modeling JF - Journal of analytical atomic spectrometry PY - 2010 DO - https://doi.org/10.1039/C0JA00016G SN - 0267-9477 SN - 1364-5544 VL - 25 SP - 1643 EP - 1653 PB - Royal Society of Chemistry CY - London AN - OPUS4-22942 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Panne, Ulrich T1 - Radiative models of laser-induced plasma and pump-probe diagnostics relevant to laser-induced breakdown spectroscopy JF - Spectrochimica acta B N2 - The paper describes past and present efforts in modeling of laser-induced plasma and overviews plasma diagnostics carried out by pump-probe techniques. Besides general information on existing plasma models, the emphasis is given to models relevant to spectrochemical analysis, i.e. models of radiating plasma. Special attention is paid to collisional-radiative (CR) and collisional-dominated (CD) plasma models where radiative processes play an important role. Also, calibration-free (CF) models are considered which may endow with the possibility for standardless spectroscopic analysis. In the diagnostic part, only methods based on the use of additional diagnostic tools (auxiliary lasers, optics, and probes) are described omitting those based on plasma own radiation. A short review is provided on image-based diagnostics (shadowgraphy, schlieren, and interferometry), absorption and fluorescence, Langmuir probe, and less frequently used cavity ringdown and Thomson scattering methods. KW - Laser ablation KW - Modeling KW - Plasma diagnostics KW - Laser-induced breakdown spectroscopy PY - 2010 DO - https://doi.org/10.1016/j.sab.2010.03.021 SN - 0584-8547 SN - 0038-6987 VL - 65 IS - 5 SP - 345 EP - 359 PB - Elsevier CY - Amsterdam AN - OPUS4-24003 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Höhse, Marek A1 - Gornushkin, Igor B. A1 - Merk, Sven A1 - Panne, Ulrich T1 - Assessment of suitability of diode pumped solid state lasers for laser induced breakdown and Raman spectroscopy JF - Journal of analytical atomic spectrometry N2 - The potential of a diode pumped solid state (DPSS) laser for laser induced breakdown spectroscopy (LIBS) and Raman spectroscopy was investigated. The DPSS laser operating at repetition rates of 1 Hz–200 kHz, pulse energy of ~1 mJ, and pulse duration of ~20 ns was added to a conventional LIBS system equipped with the flashlamp-pumped Nd:YAG laser (10 Hz, 400 mJ, 6 ns) to directly compare the two laser systems. Despite the lower mass ablated per laser pulse (~several nanograms) and a weaker plasma, the total mass ablated per measurement interval (~1 s) and total emission signal were significantly higher than those obtained with the flashlamp pumped Nd:YAG laser. This resulted in the improved signal-to-noise ratio and better limits of detection (LOD). The best LODs were obtained for Cu, Cr and Ni in ultrapure standard iron samples, 0.7 ppm, 1 ppm and 5 ppm, correspondingly. The plasma from the DPSS laser was characterized in terms of its radiative properties, temperature, and shockwave propagation speed. The suitability of this laser for LIBS-Raman was demonstrated by mapping the elemental and molecular composition of a mineral sample. The results strongly imply that DPSS lasers are the promising source for LIBS, Raman, or combined LIBS-Raman spectroscopy. PY - 2011 DO - https://doi.org/10.1039/c0ja00038h SN - 0267-9477 SN - 1364-5544 VL - 26 IS - 2 SP - 414 EP - 424 PB - Royal Society of Chemistry CY - London AN - OPUS4-22943 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Merk, Sven A1 - Shabanov, Sergej V. A1 - Gornushkin, Igor B. A1 - Panne, Ulrich T1 - Laser-induced plasma tomography by the Radon transform JF - Journal of analytical atomic spectrometry N2 - The Radon transform is tested as a method for reconstruction of the emissivity distribution of asymmetric laser induced plasmas. Two types of experiments were carried out. First, the plasma asymmetry is introduced via focusing the laser by a cylindrical lens to create plasma plumes elongated along the symmetry axis of the lens. Second, an asymmetric power distribution across the laser beam is created by reflecting the latter from a damaged mirror. Various effects on the quality of the plasma emissivity reconstructed by the Radon tomography method are investigated. The understanding of these effects appears to be essential to design a proper experimental setup to study LIBS plasmas by the Radon tomography method. It is demonstrated that the Radon tomography can successfully be used for experimental studies of asymmetric LIBS plasmas. KW - Radon transform KW - Laser induced plasma KW - LIBS KW - Plasma tomography PY - 2011 DO - https://doi.org/10.1039/c1ja10187k SN - 0267-9477 SN - 1364-5544 VL - 26 SP - 2483 EP - 2492 PB - Royal Society of Chemistry CY - London AN - OPUS4-24889 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Matiaske, Anna-Maria A1 - Gornushkin, Igor B. A1 - Panne, Ulrich T1 - Double-pulse laser-induced breakdown spectroscopy for analysis of molten glass JF - Analytical and bioanalytical chemistry N2 - A mobile double-pulse laser-induced breakdown spectroscopy system for industrial environments is presented. Its capabilities as a process analytical technique for the recovery of metals from molten inorganic wastes are investigated. Using low-melting glass doped with different amounts of additives as a model system for recycling slags, the optimum number of shots, laser inter-pulse and acquisition delay times are optimized for solid and liquid (1200 °C) glass. Limits of detection from 7 ppm (Mn) to 194 ppm (Zn) are achieved working at a distance of 75 cm from the sample. To simplify the quantification of molten samples in an industrial furnace, the possibility is examined of using solid standards for analysis of molten material. KW - Laser-induced breakdown spectroscopy KW - LIBS KW - Double-pulse LIBS KW - Molten glass KW - Recycling PY - 2011 DO - https://doi.org/10.1007/s00216-011-5165-2 SN - 1618-2642 SN - 1618-2650 VL - 402 IS - 8 SP - 2597 EP - 2606 PB - Springer CY - Berlin AN - OPUS4-23950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Shabanov, Sergej V. A1 - Panne, Ulrich T1 - Abel inversion applied to a transient laser induced plasma: implications from plasma modeling JF - Journal of analytical atomic spectrometry N2 - We test the effects of non-uniformity, non-transparency, and non-stationarity of a laser-induced plasma on the results obtained by the Abel inversion method. The method is commonly used for obtaining spatially resolved emissivity of axially symmetric non-homogeneous radiating objects. Besides the axial symmetry, the plasma is assumed to be optically thin. As the method addresses a certain plasma state, the plasma is required to be stationary during measurements. It is difficult to satisfy the aforementioned conditions for transient laser induced plasmas. As such the plasmas are not stationary; they have steep gradients of thermodynamic parameters that rapidly vary during the plasma evolution. Therefore, any conclusion based on time-integrated measurements and the corresponding data processing should account for these effects. In this work, we use the collision-dominated plasma model to generate time- and spatially resolved synthetic spectra. The spectra are processed by executing the Abel inversion using two numerical algorithms. Thus obtained spatially resolved plasma parameters (emissivity, temperature, and number density) are compared with the exact parameters used to set up the model. In doing so, the accuracy of the Abel inversion method is assessed. Special attention is paid to the dynamic aspect of the expanding plasma and possible errors which result from time-integrated measurements. PY - 2011 DO - https://doi.org/10.1039/c1ja10044k SN - 0267-9477 SN - 1364-5544 VL - 26 IS - 7 SP - 1457 EP - 1465 PB - Royal Society of Chemistry CY - London AN - OPUS4-25824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gornushkin, Igor B. A1 - Merk, Sven A1 - Demidov, Alexandr A1 - Panne, Ulrich A1 - Shabanov, Sergej V. A1 - Smith, B.W. A1 - Omenetto, N. T1 - Tomography of single and double pulse laser-induced plasma using Radon transform technique JF - Spectrochimica acta B N2 - The Radon transform tomography is used for reconstruction of the emissivity distribution in single- (SP) and double-pulse (DP) laser induced plasmas in orthogonal geometry. The orthogonal DP plasma is intrinsically asymmetric and thus suitable for the Radon reconstruction. The DP plasma consists of two plasmas separated by a short time interval of ~ 1 µs. The first plasma is created in air near the surface of a Si wafer and is followed (pre-ablation mode) or preceded (post-ablation mode) by the second plasma induced on this surface. A spectrometer moves in a semi-circular path around the plasma keeping the plasma in the rotation center. The optical detection is arranged so that a thin plasma layer parallel to the target surface is monitored. The axial symmetry of the SP plasma is investigated by comparing data from the Abel inversion taken at different angles and Radon reconstruction. The multi-angle measurements are used to estimate errors of the Abel reconstruction due to asymmetries of the plasma. Time-resolved Radon reconstruction in white light is performed for the DP plasma in both pre- and post-ablation modes. In the former case, the effect of ablated aerosol on the formation of the air plasma is monitored. In the latter case, a formation of an asymmetric compression shock created by the target plasma inside the air plasma is visualized. This observation is supported by computer simulations. An interaction of the two plasmas is studied by spectrally resolved Radon reconstruction revealing a complex distribution of target and ambient species inside the plasma at all studied delay times. Overall, it is demonstrated that Radon-based tomography is an informative tool to study transient asymmetric laser induced plasmas. KW - Radon transform tomography of SP KW - DP laser induced plasma KW - LIBS KW - Orthogonal double pulse plasma PY - 2012 DO - https://doi.org/10.1016/j.sab.2012.06.033 SN - 0584-8547 SN - 0038-6987 VL - 76 SP - 203 EP - 213 PB - Elsevier CY - Amsterdam AN - OPUS4-27438 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -