National Library of Energy BETA

Sample records for laser-induced breakdown spectroscopy

  1. Overview of applications of Laser-Induced Breakdown Spectroscopy (LIBS)

    SciTech Connect (OSTI)

    Cremers, D.A.

    1987-01-01

    Laser-induced breakdown spectroscopy (LIBS) is a method of performing elemental analyses of solids, liquids, and gases using the microplasma produced by a focused laser pulse. Because the microplasma is formed by optical radiation, LIBS has some important advantages compared to conventional laboratory based analytical methods. Three applications are discussed which use the LIBS method. 6 refs., 8 figs., 2 tabs.

  2. Improved Laser Induced Breakdown Spectroscopy (LIBS) Elemental Composition

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Detection System - Energy Innovation Portal Industrial Technologies Industrial Technologies Geothermal Geothermal Find More Like This Return to Search Improved Laser Induced Breakdown Spectroscopy (LIBS) Elemental Composition Detection System A device to measure subsurface gases, liquids, and solids at subsurface conditions National Energy Technology Laboratory Contact NETL About This Technology Technology Marketing Summary This device can measure subsurface gases, liquids, and solids at

  3. Laser-induced breakdown spectroscopy for specimen analysis

    DOE Patents [OSTI]

    Kumar, Akshaya; Yu-Yueh, Fang; Burgess, Shane C.; Singh, Jagdish P.

    2006-08-15

    The present invention is directed to an apparatus, a system and a method for detecting the presence or absence of trace elements in a biological sample using Laser-Induced Breakdown Spectroscopy. The trace elements are used to develop a signature profile which is analyzed directly or compared with the known profile of a standard. In one aspect of the invention, the apparatus, system and method are used to detect malignant cancer cells in vivo.

  4. Analysis of organic vapors with laser induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Nozari, Hadi; Tavassoli, Seyed Hassan; Rezaei, Fatemeh

    2015-09-15

    In this paper, laser induced breakdown spectroscopy (LIBS) is utilized in the study of acetone, ethanol, methanol, cyclohexane, and nonane vapors. Carbon, hydrogen, oxygen, and nitrogen atomic emission spectra have been recorded following laser-induced breakdown of the organic vapors that are mixed with air inside a quartz chamber at atmospheric pressure. The plasma is generated with focused, Q-switched Nd:YAG radiation at the wavelength of 1064 nm. The effects of ignition and vapor pressure are discussed in view of the appearance of the emission spectra. The recorded spectra are proportional to the vapor pressure in air. The hydrogen and oxygen contributions diminish gradually with consecutive laser-plasma events without gas flow. The results show that LIBS can be used to characterize organic vapor.

  5. Laser-induced breakdown spectroscopy of alcohols and protein solutions

    SciTech Connect (OSTI)

    Melikechi, N.; Ding, H.; Marcano, O. A.; Rock, S.

    2008-04-15

    We report on the use of laser-induced breakdown spectroscopy for the study of organic samples that exhibit similar elemental composition. We evaluate the method for its potential application for the measurement of small spectroscopic differences between samples such as alcohols and water solution of proteins. We measure differences in the relative amplitudes of the oxygen peaks for alcohols and find that these correlate with the relative amount of oxygen atoms within the molecule. We also show that the spectra of proteins reveal differences that can be used for their detection and identification.

  6. Laser-induced fluorescence-cued, laser-induced breakdown spectroscopy biological-agent detection

    SciTech Connect (OSTI)

    Hybl, John D.; Tysk, Shane M.; Berry, Shaun R.; Jordan, Michael P

    2006-12-01

    Methods for accurately characterizing aerosols are required for detecting biological warfare agents. Currently, fluorescence-based biological agent sensors provide adequate detection sensitivity but suffer from high false-alarm rates. Combining single-particle fluorescence analysis with laser-induced breakdown spectroscopy (LIBS) provides additional discrimination and potentially reduces false-alarm rates. A transportable UV laser-induced fluorescence-cued LIBS test bed has been developed and used to evaluate the utility of LIBS for biological-agent detection. Analysis of these data indicates that LIBS adds discrimination capability to fluorescence-based biological-agent detectors.However, the data also show that LIBS signatures of biological agent simulants are affected by washing. This may limit the specificity of LIBS and narrow the scope of its applicability in biological-agent detection.

  7. Apparatus, system, and method for laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Effenberger, Jr., Andrew J; Scott, Jill R; McJunkin, Timothy R

    2014-11-18

    In laser-induced breakdown spectroscopy (LIBS), an apparatus includes a pulsed laser configured to generate a pulsed laser signal toward a sample, a constructive interference object and an optical element, each located in a path of light from the sample. The constructive interference object is configured to generate constructive interference patterns of the light. The optical element is configured to disperse the light. A LIBS system includes a first and a second optical element, and a data acquisition module. The data acquisition module is configured to determine an isotope measurement based, at least in part, on light received by an image sensor from the first and second optical elements. A method for performing LIBS includes generating a pulsed laser on a sample to generate light from a plasma, generating constructive interference patterns of the light, and dispersing the light into a plurality of wavelengths.

  8. Laser-induced breakdown spectroscopy in industrial and security applications

    SciTech Connect (OSTI)

    Bol'shakov, Alexander A.; Yoo, Jong H.; Liu Chunyi; Plumer, John R.; Russo, Richard E.

    2010-05-01

    Laser-induced breakdown spectroscopy (LIBS) offers rapid, localized chemical analysis of solid or liquid materials with high spatial resolution in lateral and depth profiling, without the need for sample preparation. Principal component analysis and partial least squares algorithms were applied to identify a variety of complex organic and inorganic samples. This work illustrates how LIBS analyzers can answer a multitude of real-world needs for rapid analysis, such as determination of lead in paint and children's toys, analysis of electronic and solder materials, quality control of fiberglass panels, discrimination of coffee beans from different vendors, and identification of generic versus brand-name drugs. Lateral and depth profiling was performed on children's toys and paint layers. Traditional one-element calibration or multivariate chemometric procedures were applied for elemental quantification, from single laser shot determination of metal traces at {approx}10 {mu}g/g to determination of halogens at 90 {mu}g/g using 50-shot spectral accumulation. The effectiveness of LIBS for security applications was demonstrated in the field by testing the 50-m standoff LIBS rasterizing detector.

  9. Note: A novel technique for analysis of aqueous solutions by laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Rusak, D. A.; Bell, Z. T.; Anthony, T. P.

    2015-11-15

    Surface-enhanced Raman spectroscopy (SERS) substrates typically consist of gold or silver nanoparticles deposited on a non-conductive substrate. In Raman spectroscopy, the nanoparticles produce an enhancement of the electromagnetic field which, in turn, leads to greater electronic excitation of molecules in the local environment. Here, we show that these same surfaces can be used to enhance the signal-to-noise ratio obtained in laser-induced breakdown spectroscopy of aqueous solutions. In this case, the SERS substrates not only lower breakdown thresholds and lead to more efficient plasma initiation but also provide an appropriately wettable surface for the deposition of the liquid. We refer to this technique as surface-enhanced laser-induced breakdown spectroscopy.

  10. Laser-induced breakdown spectroscopy at high temperatures in...

    Office of Scientific and Technical Information (OSTI)

    electric power generation boiler burning biomass, coat, or both, (2) at the exit of a ... Language: English Subject: 03 NATURAL GAS; 09 BIOMASS FUELS; BIOMASS; BOILERS; BREAKDOWN; ...

  11. Commercialization of laser-induced breakdown spectroscopy for lead-in-paint inspection

    SciTech Connect (OSTI)

    Myers, Richard A.; Kolodziejski, Noah J.; Squillante, Michael R

    2008-11-01

    A study was undertaken to determine if laser-induced breakdown spectroscopy (LIBS) can be a practical and competitive alternative to x-ray fluorescence (XRF) methods for lead-in-paint inspection. Experiments in the laboratory confirmed that LIBS is suitable for detecting lead in paint at the hazard levels defined by federal agencies. Although we compared speed, function, and cost, fundamental differences between the XRF and LIBS measurements limited our ability to make a quantitative performance comparison. While the LIBS method can achieve the required sensitivity and offers a way to obtain unique information during inspection, the current component costs will likely restrict interest in the method to niche applications.

  12. Remote Compositional Analysis of Spent-Fuel Residues Using Laser-Induced Breakdown Spectroscopy

    SciTech Connect (OSTI)

    Whitehouse, A. I.; Young, J.; Evans, C. P.; Brown, A.; Simpson, A.; Franco, J.

    2003-02-26

    We report on the application of a novel technique known as Laser-Induced Breakdown Spectroscopy (LIBS) for remotely detecting and characterizing the elemental composition of highly radioactive materials including spent-fuel residues and High-Level Waste (HLW). Within the UK nuclear industry, LIBS has been demonstrated to offer a convenient alternative to sampling and laboratory analysis of a wide range of materials irrespective of the activity of the material or the ambient radiation levels. Proven applications of this technology include in-situ compositional analysis of nuclear reactor components, remote detection and characterization of vitrified HLW and remote compositional analysis of highly-active gross contamination within a spent-fuel reprocessing plant.

  13. Laser-induced breakdown spectroscopy measurement in methane and biodiesel flames using an ungated detector

    SciTech Connect (OSTI)

    Eseller, Kemal E.; Yueh, Fang Y.; Singh, Jagdish P

    2008-11-01

    Laser-induced breakdown spectroscopy (LIBS) has been applied to measure the equivalence ratio of CH4/air flames using gated detection. In this work, we have developed an ungated, miniature LIBS-based sensor for studying CH4/air and biodiesel flames. We have used this sensor to characterize the biodiesel flame. LIBS spectra of biodiesel flames were recorded with different ethanol concentrations in the biodiesel and also at different axial locations within the flame. The sensor performance was evaluated with a CH4/air flame. LIBS signals of N, O, and H from a CH4/air flame were used to determine the equivalence ratio. A linear relationship between the intensity ratio of H and O lines and the calculated equivalence ratio were obtained with this sensor.

  14. Fiber optic laser-induced breakdown spectroscopy sensor for molten material analysis

    DOE Patents [OSTI]

    Zhang, Hansheng; Rai, Awadesh K.; Singh, Jagdish P.; Yueh, Fang-Yu

    2004-07-13

    A fiber optic laser-induced breakdown spectroscopy (LIBS) sensor, including a laser light source, a harmonic separator for directing the laser light, a dichroic mirror for reflecting the laser light, a coupling lens for coupling the laser light at an input of a multimode optical fiber, a connector for coupling the laser light from an output of the multimode optical fiber to an input of a high temperature holder, such as a holder made of stainless steel, and a detector portion for receiving emission signal and analyzing LIBS intensities. In one variation, the multimode optical fiber has silica core and silica cladding. The holder includes optical lenses for collimating and focusing the laser light in a molten alloy to produce a plasma, and for collecting and transmitting an emission signal to the multimode optical fiber.

  15. Determination of a brass alloy concentration composition using calibration-free laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Achouri, M.; Baba-Hamed, T.; Beldjilali, S. A. Belasri, A.

    2015-09-15

    Laser-induced breakdown spectroscopy (LIBS) is a technique that can provide qualitative and quantitative measurements of the characteristics of irradiated metals. In the present work, we have calculated the parameters of the plasma produced from a brass alloy sample under the action of a pulsed Nd: YAG laser operating at 1064 nm. The emission lines of copper atoms (Cu I), zinc atoms (Zn I), and lead atoms (Pb I), which are elements of a brass alloy composition, were used to investigate the parameters of the brass plasma. The spectral profiles of Cu, Zn, and Pb lines have been used to extract the electron temperature and density of the brass alloy plasma. The characteristics of Cu, Zn, and Pb were determined quantatively by the calibration-free LIBS (CF-LIBS) method considering for accurate analysis that the laser-induced ablated plasma is optically thin in local thermodynamic equilibrium conditions and the plasma ablation is stoichiometric. The Boltzmann plot method was used to evaluate the plasma temperature, and the Stark broadened profiles were used to determine the electron density. An algorithm based on the experimentally measured values of the intensity of spectral lines and the basic laws of plasma physics was developed for the determination of Cu, Zn, and Pb concentrations in the brass sample. The concentrations C{sub CF-LIBS} calculated by CF-LIBS and the certified concentrations C{sub certified} were very close.

  16. Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

    SciTech Connect (OSTI)

    Martin, Madhavi Z; Fox, Dr. Richard V; Miziolek, Andrzej W; DeLucia, Frank C; Andre, Nicolas O

    2015-01-01

    There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in real-world complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

  17. Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

    SciTech Connect (OSTI)

    Martin, Madhavi Z; Fox, Dr. Richard V; Miziolek, Andrzej W; DeLucia, Frank C; Andre, Nicolas O

    2015-01-01

    There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in realworld complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

  18. Spectral Analysis of Rare Earth Elements using Laser-Induced Breakdown Spectroscopy

    SciTech Connect (OSTI)

    Madhavi Z. Martin; Robert V. Fox; Andrzej W. Miziolek; Frank C. DeLucia, Jr.; Nicolas Andre

    2001-05-01

    There is growing interest in rapid analysis of rare earth elements (REEs) both due to the need to find new natural sources to satisfy increased demand in their use in various electronic devices, as well as the fact that they are used to estimate actinide masses for nuclear safeguards and nonproliferation. Laser-Induced Breakdown Spectroscopy (LIBS) appears to be a particularly well-suited spectroscopy-based technology to rapidly and accurately analyze the REEs in various matrices at low concentration levels (parts-per-million). Although LIBS spectra of REEs have been reported for a number of years, further work is still necessary in order to be able to quantify the concentrations of various REEs in realworld complex samples. LIBS offers advantages over conventional solution-based radiochemistry in terms of cost, analytical turnaround, waste generation, personnel dose, and contamination risk. Rare earth elements of commercial interest are found in the following three matrix groups: 1) raw ores and unrefined materials, 2) as components in refined products such as magnets, lighting phosphors, consumer electronics (which are mostly magnets and phosphors), catalysts, batteries, etc., and 3) waste/recyclable materials (aka e-waste). LIBS spectra for REEs such as Gd, Nd, and Sm found in rare earth magnets are presented.

  19. Investigation of historical metal objects using Laser Induced Breakdown Spectroscopy (LIBS) technique

    SciTech Connect (OSTI)

    Abdel-Kareem, O.; Ghoneim, M.; Harith, M. A.

    2011-09-22

    Analysis of metal objects is a necessary step for establishing an appropriate conservation treatment of an object or to follow up the application's result of the suggested treatments. The main considerations on selecting a method that can be used in investigation and analysis of metal objects are based on the diagnostic power, representative sampling, reproducibility, destructive nature/invasiveness of analysis and accessibility to the appropriate instrument. This study aims at evaluating the usefulness of the use of Laser Induced Breakdown Spectroscopy (LIBS) Technique for analysis of historical metal objects. In this study various historical metal objects collected from different museums and excavations in Egypt were investigated using (LIBS) technique. For evaluating usefulness of the suggested analytical protocol of this technique, the same investigated metal objects were investigated by other methods such as Scanning Electron Microscope with energy-dispersive x-ray analyzer (SEM-EDX) and X-ray Diffraction (XRD). This study confirms that Laser Induced Breakdown Spectroscopy (LIBS) Technique is considered very useful technique that can be used safely for investigating historical metal objects. LIBS analysis can quickly provide information on the qualitative and semi-quantitative elemental content of different metal objects and their characterization and classification. It is practically non-destructive technique with the critical advantage of being applicable in situ, thereby avoiding sampling and sample preparations. It is can be dependable, satisfactory and effective method for low cost study of archaeological and historical metals. But we have to take into consideration that the corrosion of metal leads to material alteration and possible loss of certain metals in the form of soluble salts. Certain corrosion products are known to leach out of the object and therefore, their low content does not necessarily reflect the composition of the metal at the time of

  20. Practical high resolution detection method for laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Andrew J. Effenberger Jr; Jill R. Scott

    2012-02-01

    A Fabry-Perot etalon was coupled to a Czerny-Turner spectrometer to acquire high-resolution measurements in laser-induced breakdown spectroscopy (LIBS). The spectrometer was built using an inexpensive etalon coupled to a standard 0.5-m imaging spectrometer. The Hg emission doublet at 313.2 nm was used to evaluate instrument performance because it has a splitting of 29 pm. The 313.2 nm doublet was chosen due to the similar splitting seen in isotope splitting from uranium at 424.437 nm, which is 25 pm. The Hg doublet was easily resolved from a continuous source Hg-lamp with a 2 s acquisition. The doublet was also resolved in LIBS spectra of cinnabar (HgS) from the accumulation of 600 laser shots at rate of 10 Hz, or 1 min, under a helium atmosphere. In addition to observed spitting of the 313.2 nm Hg doublet, the FWHM of the 313.1844 nm line from the doublet is reported at varying He atmospheric pressures. The high performance, low cost, and compact footprint makes this system highly competitive with 2-m double pass Czerny-Turner spectrometers.

  1. Quantification of rare earth elements using laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Martin, Madhavi; Martin, Rodger C.; Allman, Steve; Brice, Deanne; Wymore, Ann; Andre, Nicolas

    2015-10-21

    In this paper, a study of the optical emission as a function of concentration of laser-ablated yttrium (Y) and of six rare earth elements, europium (Eu), gadolinium (Gd), lanthanum (La), praseodymium (Pr), neodymium (Nd), and samarium (Sm), has been evaluated using the laser-induced breakdown spectroscopy (LIBS) technique. Statistical methodology using multivariate analysis has been used to obtain the sampling errors, coefficient of regression, calibration, and cross-validation of measurements as they relate to the LIBS analysis in graphite-matrix pellets that were doped with elements at several concentrations. Each element (in oxide form) was mixed in the graphite matrix in percentages ranging from 1% to 50% by weight and the LIBS spectra obtained for each composition as well as for pure oxide samples. Finally, a single pellet was mixed with all the elements in equal oxide masses to determine if we can identify the elemental peaks in a mixed pellet. This dataset is relevant for future application to studies of fission product content and distribution in irradiated nuclear fuels. These results demonstrate that LIBS technique is inherently well suited for the future challenge of in situ analysis of nuclear materials. Finally, these studies also show that LIBS spectral analysis using statistical methodology can provide quantitative results and suggest an approach in future to the far more challenging multielemental analysis of ~ 20 primary elements in high-burnup nuclear reactor fuel.

  2. Quantification of rare earth elements using laser-induced breakdown spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Martin, Madhavi; Martin, Rodger C.; Allman, Steve; Brice, Deanne; Wymore, Ann; Andre, Nicolas

    2015-10-21

    In this paper, a study of the optical emission as a function of concentration of laser-ablated yttrium (Y) and of six rare earth elements, europium (Eu), gadolinium (Gd), lanthanum (La), praseodymium (Pr), neodymium (Nd), and samarium (Sm), has been evaluated using the laser-induced breakdown spectroscopy (LIBS) technique. Statistical methodology using multivariate analysis has been used to obtain the sampling errors, coefficient of regression, calibration, and cross-validation of measurements as they relate to the LIBS analysis in graphite-matrix pellets that were doped with elements at several concentrations. Each element (in oxide form) was mixed in the graphite matrix in percentages rangingmore » from 1% to 50% by weight and the LIBS spectra obtained for each composition as well as for pure oxide samples. Finally, a single pellet was mixed with all the elements in equal oxide masses to determine if we can identify the elemental peaks in a mixed pellet. This dataset is relevant for future application to studies of fission product content and distribution in irradiated nuclear fuels. These results demonstrate that LIBS technique is inherently well suited for the future challenge of in situ analysis of nuclear materials. Finally, these studies also show that LIBS spectral analysis using statistical methodology can provide quantitative results and suggest an approach in future to the far more challenging multielemental analysis of ~ 20 primary elements in high-burnup nuclear reactor fuel.« less

  3. Exploring laser-induced breakdown spectroscopy for nuclear materials analysis and in-situ applications

    SciTech Connect (OSTI)

    Martin, Madhavi Z; Allman, Steve L; Brice, Deanne Jane; Martin, Rodger Carl; Andre, Nicolas O

    2012-01-01

    Laser-induced breakdown spectroscopy (LIBS) has been used to determine the limits of detection of strontium (Sr) and cesium (Cs), common nuclear fission products. Additionally, detection limits were determined for cerium (Ce), often used as a surrogate for radioactive plutonium in laboratory studies. Results were obtained using a laboratory instrument with a Nd:YAG laser at fundamental wavelength of 1064 nm, frequency doubled to 532 nm with energy of 50 mJ/pulse. The data was compared for different concentrations of Sr and Ce dispersed in a CaCO3 (white) and carbon (black) matrix. We have addressed the sampling errors, limits of detection, reproducibility, and accuracy of measurements as they relate to multivariate analysis in pellets that were doped with the different elements at various concentrations. These results demonstrate that LIBS technique is inherently well suited for in situ analysis of nuclear materials in hot cells. Three key advantages are evident: (1) small samples (mg) can be evaluated; (2) nuclear materials can be analyzed with minimal sample preparation; and (3) samples can be remotely analyzed very rapidly (ms-seconds). Our studies also show that the methods can be made quantitative. Very robust multivariate models have been used to provide quantitative measurement and statistical evaluation of complex materials derived from our previous research on wood and soil samples.

  4. Temperature effect on laser-induced breakdown spectroscopy spectra of molten and solid salts

    SciTech Connect (OSTI)

    Cynthia Hanson; Supathorn Phongikaroon; Jill R. Scott

    2014-07-01

    Laser-induced breakdown spectroscopy (LIBS) has been investigated as a potential analytical tool to improve operations and safeguards for electrorefiners, such as those used in processing spent nuclear fuel. This study set out to better understand the effect of sample temperature and physical state on LIBS spectra of molten and solid salts by building calibration curves of cerium and assessing self-absorption, plasma temperature, electron density, and local thermal equilibrium (LTE). Samples were composed of a LiCl–KCl eutectic salt, an internal standard of MnCl2, and varying concentrations of CeCl3 (0.1, 0.3, 0.5, 0.8, and 1.0 wt.% Ce) under different temperatures (773, 723, 673, 623, and 573 K). Analysis of salts in their molten form is preferred as plasma plumes from molten samples experienced less self-absorption, less variability in plasma temperature, and higher clearance of the minimum electron density required for local thermal equilibrium. These differences are attributed to plasma dynamics as a result of phase changes. Spectral reproducibility was also better in the molten state due to sample homogeneity.

  5. Rapid Analysis of Ash Composition Using Laser-Induced Breakdown Spectroscopy (LIBS)

    SciTech Connect (OSTI)

    Tyler L. Westover

    2013-01-01

    Inorganic compounds are known to be problematic in the thermochemical conversion of biomass to syngas and ultimately hydrocarbon fuels. The elements Si, K, Ca, Na, S, P, Cl, Mg, Fe, and Al are particularly problematic and are known to influence reaction pathways, contribute to fouling and corrosion, poison catalysts, and impact waste streams. Substantial quantities of inorganic species can be entrained in the bark of trees during harvest operations. Herbaceous feedstocks often have even greater quantities of inorganic constituents, which can account for as much as one-fifth of the total dry matter. Current methodologies to measure the concentrations of these elements, such as inductively coupled plasma-optical emission spectrometry/mass spectrometry (ICP-OES/MS) are expensive in time and reagents. This study demonstrates that a new methodology employing laser-induced breakdown spectroscopy (LIBS) can rapidly and accurately analyze the inorganic constituents in a wide range of biomass materials, including both woody and herbaceous examples. This technique requires little or no sample preparation, does not consume any reagents, and the analytical data is available immediately. In addition to comparing LIBS data with the results from ICP-OES methods, this work also includes discussions of sample preparation techniques, calibration curves for interpreting LIBS spectra, minimum detection limits, and the use of internal standards and standard reference materials.

  6. High-Resolution Laser-Induced Breakdown Spectroscopy used in Homeland Security and Forensic Applications

    SciTech Connect (OSTI)

    Martin, Madhavi Z; Wullschleger, Stan D; Vass, Arpad Alexander; Martin, Rodger Carl; Grissino-Mayer, Henri

    2006-01-01

    The technique of laser-induced breakdown spectroscopy (LIBS) to detect elements for a variety of homeland security applications such as nuclear materials identification and inventory,and forensic applications has been demonstrated. For nuclear materials applications, we detected and profiled metals in coatings that were used to encapsulate nuclear fuel. Multivariate analysis has been successfully employed in the quantification of elements present in treated wood and engineered wood composites. These examples demonstrate that LIBS-based techniques are inherently well suited for diverse environmental applications related to homeland security. Three key advantages are evident: (1) small samples (mg) are sufficient; (2) samples can be analyzed by LIBS very rapidly, and (3) biological materials such as human and animal bones and wood can be analyzed with minimal sample preparation. For forensic applications they have used LIBS to determine differences in animal and human bones. They have also applied this technique in the determination of counterfeit and non-counterfeit currency. They recently applied LIBS in helping to solve a murder case.

  7. Preliminary design of laser-induced breakdown spectroscopy for proto-Material Plasma Exposure eXperiment

    SciTech Connect (OSTI)

    Shaw, G.; Martin, M. Z.; Martin, R.; Biewer, T. M.

    2014-11-15

    Laser-induced breakdown spectroscopy (LIBS) is a technique for measuring surface matter composition. LIBS is performed by focusing laser radiation onto a target surface, ablating the surface, forming a plasma, and analyzing the light produced. LIBS surface analysis is a possible diagnostic for characterizing plasma-facing materials in ITER. Oak Ridge National Laboratory has enabled the initial installation of a laser-induced breakdown spectroscopy diagnostic on the prototype Material-Plasma Exposure eXperiment (Proto-MPEX), which strives to mimic the conditions found at the surface of the ITER divertor. This paper will discuss the LIBS implementation on Proto-MPEX, preliminary design of the fiber optic LIBS collection probe, and the expected results.

  8. Application of laser induced breakdown spectroscopy (LIBS) instrumentation for international safeguards

    SciTech Connect (OSTI)

    Barefield Ii, James E; Clegg, Samuel M; Lopez, Leon N; Le, Loan A; Veirs, D Kirk; Browne, Mike

    2010-01-01

    Advanced methodologies and improvements to current measurements techniques are needed to strengthen the effectiveness and efficiency of international safeguards. This need was recognized and discussed at a Technical Meeting on 'The Application of Laser Spectrometry Techniques in IAEA Safeguards' held at IAEA headquarters (September 2006). One of the principal recommendations from that meeting was the need to pursue the development of novel complementary access instrumentation based on Laser Induced Breakdown Spectroscopy (UBS) for the detection of gaseous and solid signatures and indicators of nuclear fuel cycle processes and associated materials'. Pursuant to this recommendation the Department of Safeguards (SG) under the Division of Technical Support (SGTS) convened the 'Experts and Users Advisory Meeting on Laser Induced Breakdown Spectroscopy (LIBS) for Safeguards Applications' also held at IAEA headquarters (July 2008). This meeting was attended by 12 LlBS experts from the Czech Republic, the European Commission, France, the Republic of South Korea, the United States of America, Germany, the United Kingdom of Great Britain, Canada, and Northern Ireland. Following a presentation of the needs of the IAEA inspectors, the LIBS experts agreed that needs as presented could be partially or fully fulfilled using LIBS instrumentation. Inspectors needs were grouped into the following broad categories: (1) Improvements to in-field measurements/environmental sampling; (2) Monitoring status of activities in Hot Cells; (3) Verify status of activity at a declared facility via process monitoring; and (4) Need for pre-screening of environmental samples before analysis. The primary tool employed by the IAEA to detect undeclared processes and activities at special nuclear material facilities and sites is environmental sampling. One of the objectives of the Next Generation Safeguards Initiative (NGSI) Program Plan calls for the development of advanced tools and methodologies to

  9. Remote Raman - laser induced breakdown spectroscopy (LIBS) geochemical investigation under Venus atmospheric conditions

    SciTech Connect (OSTI)

    Clegg, Sanuel M; Barefield, James E; Humphries, Seth D; Wiens, Roger C; Vaniman, D. T.; Sharma, S. K.; Misra, A. K.; Dyar, M. D.; Smrekar, S. E.

    2010-12-13

    The extreme Venus surface temperatures ({approx}740 K) and atmospheric pressures ({approx}93 atm) create a challenging environment for surface missions. Scientific investigations capable of Venus geochemical observations must be completed within hours of landing before the lander will be overcome by the harsh atmosphere. A combined remote Raman - LIBS (Laser Induced Breakdown Spectroscopy) instrument is capable of accomplishing the geochemical science goals without the risks associated with collecting samples and bringing them into the lander. Wiens et al. and Sharma et al. demonstrated that both analytical techniques can be integrated into a single instrument capable of planetary missions. The focus of this paper is to explore the capability to probe geologic samples with Raman - LIBS and demonstrate quantitative analysis under Venus surface conditions. Raman and LIBS are highly complementary analytical techniques capable of detecting both the mineralogical and geochemical composition of Venus surface materials. These techniques have the potential to profoundly increase our knowledge of the Venus surface composition, which is currently limited to geochemical data from Soviet Venera and VEGA landers that collectively suggest a surface composition that is primarily tholeiitic basaltic with some potentially more evolved compositions and, in some locations, K-rich trachyandesite. These landers were not equipped to probe the surface mineralogy as can be accomplished with Raman spectroscopy. Based on the observed compositional differences and recognizing the imprecise nature of the existing data, 15 samples were chosen to constitute a Venus-analog suite for this study, including five basalts, two each of andesites, dacites, and sulfates, and single samples of a foidite, trachyandesite, rhyolite, and basaltic trachyandesite under Venus conditions. LIBS data reduction involved generating a partial least squares (PLS) model with a subset of the rock powder standards to

  10. Identification of vapor-phase chemical warfare agent simulants and rocket fuels using laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Stearns, Jaime A.; McElman, Sarah E.; Dodd, James A.

    2010-05-01

    Application of laser-induced breakdown spectroscopy (LIBS) to the identification of security threats is a growing area of research. This work presents LIBS spectra of vapor-phase chemical warfare agent simulants and typical rocket fuels. A large dataset of spectra was acquired using a variety of gas mixtures and background pressures and processed using partial least squares analysis. The five compounds studied were identified with a 99% success rate by the best method. The temporal behavior of the emission lines as a function of chamber pressure and gas mixture was also investigated, revealing some interesting trends that merit further study.

  11. Femtosecond laser induced breakdown for combustion diagnostics

    SciTech Connect (OSTI)

    Kotzagianni, M.; Couris, S.

    2012-06-25

    The focused beam of a 100 fs, 800 nm laser is used to induce a spark in some laminar premixed air-methane flames operating with variable fuel content (equivalence ratio). The analysis of the light escaping from the plasma revealed that the Balmer hydrogen lines, H{sub {alpha}} and H{sub {beta}}, and some molecular origin emissions were the most prominent spectral features, while the CN ({Beta}{sup 2}{Sigma}{sup +}-{Chi}{sup 2}{Sigma}{sup +}) band intensity was found to depend linearly with methane content, suggesting that femtosecond laser induced breakdown spectroscopy can be a useful tool for the in-situ determination and local mapping of fuel content in hydrocarbon-air combustible mixtures.

  12. Elemental content of enamel and dentin after bleaching of teeth (a comparative study between laser-induced breakdown spectroscopy and x-ray photoelectron spectroscopy)

    SciTech Connect (OSTI)

    Imam, H.; Ahmed, Doaa; Eldakrouri, Ashraf; Department of Optometry and Vision Science, College of Applied Medical Science, King Saud University, Riyadh

    2013-06-21

    The elemental content of the superficial and inner enamel as well as that of dentin was analyzed using laser-induced breakdown spectroscopy (LIBS) and x-ray photoelectron spectroscopy (XPS) of bleached and unbleached tooth specimens. It is thus clear from the spectral analysis using both the LIBS and XPS technique that elemental changes (though insignificant within the scopes of this study) of variable intensities do occur on the surface of the enamel and extend deeper to reach dentin. The results of the LIBS revealed a slight reduction in the calcium levels in the bleached compared to the control specimens in all the different bleaching groups and in both enamel and dentin. The good correlation found between the LIBS and XPS results demonstrates the possibility of LIBS technique for detection of minor loss in calcium and phosphorus in enamel and dentin.

  13. Detection of rare earth elements in Powder River Basin sub-bituminous coal ash using laser-induced breakdown spectroscopy (LIBS)

    SciTech Connect (OSTI)

    Tran, Phuoc

    2015-10-01

    We reported our preliminary results on the use of laser-induced breakdown spectroscopy to analyze the rare earth elements contained in ash samples from Powder River Basin sub-bituminous coal (PRB-coal). We have identified many elements in the lanthanide series (cerium, europium, holmium, lanthanum, lutetium, praseodymium, promethium, samarium, terbium, ytterbium) and some elements in the actinide series (actinium, thorium, uranium, plutonium, berkelium, californium) in the ash samples. In addition, various metals were also seen to present in the ash samples

  14. Laser Induced Spectroscopy - Energy Innovation Portal

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laser Induced Spectroscopy Idaho National Laboratory Contact INL About This Technology Technology Marketing Summary INL's Laser Induced Spectroscopy technology detects and measures ...

  15. Homogeneity testing and quantitative analysis of manganese (Mn) in vitrified Mn-doped glasses by laser-induced breakdown spectroscopy (LIBS)

    SciTech Connect (OSTI)

    Unnikrishnan, V. K.; Nayak, Rajesh; Kartha, V. B.; Santhosh, C. E-mail: unnikrishnan.vk@manipal.edu; Sonavane, M. S.; Yeotikar, R. G.; Shah, M. L.; Gupta, G. P.; Suri, B. M.

    2014-09-15

    Laser-induced breakdown spectroscopy (LIBS), an atomic emission spectroscopy method, has rapidly grown as one of the best elemental analysis techniques over the past two decades. Homogeneity testing and quantitative analysis of manganese (Mn) in manganese-doped glasses have been carried out using an optimized LIBS system employing a nanosecond ultraviolet Nd:YAG laser as the source of excitation. The glass samples have been prepared using conventional vitrification methods. The laser pulse irradiance on the surface of the glass samples placed in air at atmospheric pressure was about 1.710{sup 9} W/cm{sup 2}. The spatially integrated plasma emission was collected and imaged on to the spectrograph slit using an optical-fiber-based collection system. Homogeneity was checked by recording LIBS spectra from different sites on the sample surface and analyzing the elemental emission intensities for concentration determination. Validation of the observed LIBS results was done by comparison with scanning electron microscope- energy dispersive X-ray spectroscopy (SEM-EDX) surface elemental mapping. The analytical performance of the LIBS system has been evaluated through the correlation of the LIBS determined concentrations of Mn with its certified values. The results are found to be in very good agreement with the certified concentrations.

  16. Performance testing of a Laser-Induced Breakdown Spectroscopy (LIBS) based continuous metal emissions monitor at a pyrolytic waste treatment facility

    SciTech Connect (OSTI)

    Hahn, D.W.; Hencken, K.R.; Johnsen, H.A.

    1997-07-01

    A program was initiated at Sandia National Laboratories to develop and demonstrate an advanced continuous emissions monitor that will provide realtime measurement of metal emissions in the wastestreams of thermal treatment facilities. This effort led to the development of a prototype metals monitor based on an optical technique referred to as laser-induced breakdown spectroscopy (LIBS). The measurements are performed in situ, and are both noninvasive and real-time. The automated software incorporates a new conditional analysis algorithm that utilizes single particle detection. The metal emissions monitor was tested during March 1997 at a pilot scale pyrolytic waste processing facility in Santa Fe Springs, California. This report describes the field test, including the monitor installation, test cycle, and overall instrument performance. The Clean Air Act metals chromium and manganese were recorded at concentrations from approximately 2 to 5 parts per billion. Iron was recorded at concentrations from 40 to 140 parts per billion. The overall accuracy was in very good agreement with contracted EPA Reference Method 29 results. Overall, the LIBS-based metals monitor performed exceptionally well on a waste treatment facility with very low metal emissions levels. 19 refs., 12 tabs., 3 figs.

  17. Matrix effect of sodium compounds on the determination of metal ions in aqueous solutions by underwater laser-induced breakdown spectroscopy

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Goueguel, Christian; McIntyre, Dustin L.; Jain, Jinesh; Karamalidis, Athanasios K.; Carson, Cantwell

    2015-06-30

    A significant portion of the carbon sequestration research being performed in the United States involves the risk assessment of injecting large quantities of carbon dioxide into deep saline aquifers. Leakage of CO2 has the potential to affect the quality of groundwater supplies in case contaminants migrate through underlying conduits. New remote sensing and near-surface monitoring technologies are needed to ensure that injection, abandoned, and monitoring wells are structurally sound, and that CO2 remains within the geologic storage reservoir. In this paper, we propose underwater laser-induced breakdown spectroscopy (underwater LIBS) as an analytical method for monitoring naturally occurring elements that canmore » act as tracers to detect a CO2 leak from storage sites. Laboratory-scale experiments were conducted to measure Sr2+, Ca2+, K+, and Li+ in bulk solutions to ascertain the analytical performance of underwater LIBS. We compared the effect of NaCl, Na2CO3, and Na2SO4 on the analytes calibration curves to determine underwater LIBS’ ability to analyze samples of sodium compounds. In all cases, the calibration curves showed a good linearity within 2 orders of magnitude. The limit of detections (LODs) obtained for K+ (30±1 ppb) and Li+ (60±2 ppb) were in ppb range, while higher LODs were observed for Ca2+ (0.94±0.14 ppm) and Sr2+ (2.89±0.11 ppm). Evaluation of the calibration curves for the analytes in mixed solutions showed dependence of the lines’ intensity with the sodium compounds. The intensities increased respectively in the presence of dissolved NaCl and Na2SO4, whereas the intensities slightly decreased in the presence of Na2CO3. Lastly, the capabilities of underwater LIBS to detect certain elements in the ppb or in the low ppm range make it particularly appealing for in situ monitoring of a CO2 leak.« less

  18. Matrix effect of sodium compounds on the determination of metal ions in aqueous solutions by underwater laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Goueguel, Christian; McIntyre, Dustin L.; Jain, Jinesh; Karamalidis, Athanasios K.; Carson, Cantwell

    2015-06-30

    A significant portion of the carbon sequestration research being performed in the United States involves the risk assessment of injecting large quantities of carbon dioxide into deep saline aquifers. Leakage of CO2 has the potential to affect the quality of groundwater supplies in case contaminants migrate through underlying conduits. New remote sensing and near-surface monitoring technologies are needed to ensure that injection, abandoned, and monitoring wells are structurally sound, and that CO2 remains within the geologic storage reservoir. In this paper, we propose underwater laser-induced breakdown spectroscopy (underwater LIBS) as an analytical method for monitoring naturally occurring elements that can act as tracers to detect a CO2 leak from storage sites. Laboratory-scale experiments were conducted to measure Sr2+, Ca2+, K+, and Li+ in bulk solutions to ascertain the analytical performance of underwater LIBS. We compared the effect of NaCl, Na2CO3, and Na2SO4 on the analytes calibration curves to determine underwater LIBS’ ability to analyze samples of sodium compounds. In all cases, the calibration curves showed a good linearity within 2 orders of magnitude. The limit of detections (LODs) obtained for K+ (30±1 ppb) and Li+ (60±2 ppb) were in ppb range, while higher LODs were observed for Ca2+ (0.94±0.14 ppm) and Sr2+ (2.89±0.11 ppm). Evaluation of the calibration curves for the analytes in mixed solutions showed dependence of the lines’ intensity with the sodium compounds. The intensities increased respectively in the presence of dissolved NaCl and Na2SO4, whereas the intensities slightly decreased in the presence of Na2CO3. Lastly, the capabilities of underwater LIBS to detect certain elements in the ppb or in the low ppm range make it

  19. Cropland Field Monitoring: MMV Page 1 Montana Cropland Enrolled Farm Fields Carbon Sequestration Field Sampling, Measurement, Monitoring, and Verification: Application of Visible-Near Infrared Diffuse Reflectance Spectroscopy (VNIR) and Laser-induced Breakdown Spectroscopy (LIBS)

    SciTech Connect (OSTI)

    Lee Spangler; Ross Bricklemyer; David Brown

    2012-03-15

    There is growing need for rapid, accurate, and inexpensive methods to measure, and verify soil organic carbon (SOC) change for national greenhouse gas accounting and the development of a soil carbon trading market. Laboratory based soil characterization typically requires significant soil processing, which is time and resource intensive. This severely limits application for large-region soil characterization. Thus, development of rapid and accurate methods for characterizing soils are needed to map soil properties for precision agriculture applications, improve regional and global soil carbon (C) stock and flux estimates and efficiently map sub-surface metal contamination, among others. The greatest gains for efficient soil characterization will come from collecting soil data in situ, thus minimizing soil sample transportation, processing, and lab-based measurement costs. Visible and near-infrared diffuse reflectance spectroscopy (VisNIR) and laser-induced breakdown spectroscopy (LIBS) are two complementary, yet fundamentally different spectroscopic techniques that have the potential to meet this need. These sensors have the potential to be mounted on a soil penetrometer and deployed for rapid soil profile characterization at field and landscape scales. Details of sensor interaction, efficient data management, and appropriate statistical analysis techniques for model calibrations are first needed. In situ or on-the-go VisNIR spectroscopy has been proposed as a rapid and inexpensive tool for intensively mapping soil texture and organic carbon (SOC). While lab-based VisNIR has been established as a viable technique for estimating various soil properties, few experiments have compared the predictive accuracy of on-the-go and lab-based VisNIR. Eight north central Montana wheat fields were intensively interrogated using on-the-go and lab-based VisNIR. Lab-based spectral data consistently provided more accurate predictions than on-the-go data. However, neither in situ

  20. Evaluation of a commercially available passively Q-switched Nd:YAG laser with LiF:F-2 saturable absorber for laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Carson, Cantwell; Goueguel, Christian; Sanghapi, Herve; Jinesh, Jain; McIntyre, Dustin

    2015-12-11

    Interest in passively Q-switched microchip lasers as a means for miniaturization of laser-induced breakdown spectroscopy (LIBS) apparatus has rapidly grown in the last years. To explore the possibility of using a comparatively UV–vis transparent absorber, we herein present the first report on the evaluation of a commercially available flash lamp-pumped passively Q-switched Nd:YAG laser with LiF: saturable absorber as an excitation source in LIBS. Quantitative measurements of barium, strontium, rubidium and lithium in granite, rhyolite, basalt and syenite whole-rock glass samples were performed. Using a gated intensified benchtop spectrometer, limits of detection of 0.97, 23, 37, and 144 ppm were obtained for Li, Sr, Rb, and Ba, respectively. Finally, we discuss the advantages of using such a laser unit for LIBS applications in terms of ablation efficiency, analytical performances, output energy, and standoff capabilities.

  1. Preliminary Design of Laser - induced Breakd own Spectroscopy for Proto - MPEX

    SciTech Connect (OSTI)

    Shaw, Guinevere C; Biewer, T.M.; Martin, Madhavi Z; Martin, Rodger Carl

    2014-01-01

    Laser-induced breakdown spectroscopy (LIBS) is a technique for measuring surface matter composition. LIBS is performed by focusing laser radiation onto a target surface, ablating the surface, forming a plasma, and analyzing the light produced. LIBS surface analysis is a possible diagnostic for characterizing plasma-facing materials in ITER. Oak Ridge National Laboratory (ORNL) has enabled the initial installation of a laser-induced breakdown spectroscopy diagnostic on the prototype Material-Plasma Exposure eXperiment (Proto-MPEX), which strives to mimic the conditions found at the surface of the ITER divertor. This paper will discuss the LIBS implementation on Proto-MPEX, preliminary design of the fiber optic LIBS collection probe, and the expected results.

  2. Applications of laser-induced gratings to spectroscopy and dynamics

    SciTech Connect (OSTI)

    Rohlfing, E.A.

    1993-12-01

    This program has traditionally emphasized two principal areas of research. The first is the spectroscopic characterization of large-amplitude motion on the ground-state potential surface of small, transient molecules. The second is the reactivity of carbonaceous clusters and its relevance to soot and fullerene formation in combustion. Motivated initially by the desire to find improved methods of obtaining stimulated emission pumping (SEP) spectra of transients, most of our recent work has centered on the use of laser-induced gratings or resonant four-wave mixing in free-jet expansions. These techniques show great promise for several chemical applications, including molecular spectroscopy and photodissociation dynamics. The author describes recent applications of two-color laser-induced grating spectroscopy (LIGS) to obtain background-free SEP spectra of transients and double resonance spectra of nonfluorescing species, and the use of photofragment transient gratings to probe photodissociation dynamics.

  3. Acoustic monitoring method and system in laser-induced optical breakdown (LIOB)

    DOE Patents [OSTI]

    O'Donnell, Matthew; Ye, Jing Yong; Norris, Theodore B.; Baker, Jr., James R.; Balogh, Lajos P.; Milas, Susanne M.; Emelianov, Stanislav Y.; Hollman, Kyle W.

    2008-05-06

    An acoustic monitoring method and system in laser-induced optical breakdown (LIOB) provides information which characterize material which is broken down, microbubbles in the material, and/or the microenvironment of the microbubbles. In one embodiment of the invention, femtosecond laser pulses are focused just inside the surface of a volume of aqueous solution which may include dendrimer nanocomposite (DNC) particles. A tightly focused, high frequency, single-element ultrasonic transducer is positioned such that its focus coincides axially and laterally with this laser focus. When optical breakdown occurs, a microbubble forms and a shock or pressure wave is emitted (i.e., acoustic emission). In addition to this acoustic signal, the microbubble may be actively probed with pulse-echo measurements from the same transducer. After the microbubble forms, received pulse-echo signals have an extra pulse, describing the microbubble location and providing a measure of axial microbubble size. Wavefield plots of successive recordings illustrate the generation, growth, and collapse of microbubbles due to optical breakdown. These same plots can also be used to quantify LIOB thresholds.

  4. Spectral selective radio frequency emissions from laser induced breakdown of target materials

    SciTech Connect (OSTI)

    Vinoth Kumar, L.; Manikanta, E.; Leela, Ch.; Prem Kiran, P.

    2014-08-11

    The radio frequency emissions scanned over broad spectral range (30 MHz–1 GHz) from single shot nanosecond (7 ns) and picosecond (30 ps) laser induced breakdown (LIB) of different target materials (atmospheric air, aluminum, and copper) are presented. The dominant emissions from ns-LIB, compared to those from the ps-LIB, indicate the presence and importance of atomic and molecular clusters in the plasma. The dynamics of laser pulse-matter interaction and the properties of the target materials were found to play an important role in determining the plasma parameters which subsequently determine the emissions. Thus, with a particular laser and target material, the emissions were observed to be spectral selective. The radiation detection capability was observed to be relatively higher, when the polarization of the input laser and the antenna is same.

  5. Laser-induced breakdown spectroscopy of alkali metals in high...

    Office of Scientific and Technical Information (OSTI)

    LIBS sampling at lower temperatures, or in a consistently oxidizing environment, or both are suggested strategies for circumventing these difficulties. Authors: Molina, Alejandro ; ...

  6. Hybrid interferometric/dispersive atomic spectroscopy of laser-induced uranium plasma

    SciTech Connect (OSTI)

    Morgan, Phyllis K.; Scott, Jill R.; Jovanovic, Igor

    2015-12-19

    An established optical emission spectroscopy technique, laser-induced breakdown spectroscopy (LIBS), holds promise for detection and rapid analysis of elements relevant for nuclear safeguards, nonproliferation, and nuclear power, including the measurement of isotope ratios. One such important application of LIBS is the measurement of uranium enrichment (235U/238U), which requires high spectral resolution (e.g., 25 pm for the 424.4 nm U II line). High-resolution dispersive spectrometers necessary for such measurements are typically bulky and expensive. We demonstrate the use of an alternative measurement approach, which is based on an inexpensive and compact Fabry–Perot etalon integrated with a low to moderate resolution Czerny–Turner spectrometer, to achieve the resolution needed for isotope selectivity of LIBS of uranium in ambient air. Furthermore, spectral line widths of ~ 10 pm have been measured at a center wavelength 424.437 nm, clearly discriminating the natural from the highly enriched uranium.

  7. Hybrid interferometric/dispersive atomic spectroscopy of laser-induced uranium plasma

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Morgan, Phyllis K.; Scott, Jill R.; Jovanovic, Igor

    2015-12-19

    An established optical emission spectroscopy technique, laser-induced breakdown spectroscopy (LIBS), holds promise for detection and rapid analysis of elements relevant for nuclear safeguards, nonproliferation, and nuclear power, including the measurement of isotope ratios. One such important application of LIBS is the measurement of uranium enrichment (235U/238U), which requires high spectral resolution (e.g., 25 pm for the 424.4 nm U II line). High-resolution dispersive spectrometers necessary for such measurements are typically bulky and expensive. We demonstrate the use of an alternative measurement approach, which is based on an inexpensive and compact Fabry–Perot etalon integrated with a low to moderate resolution Czerny–Turnermore » spectrometer, to achieve the resolution needed for isotope selectivity of LIBS of uranium in ambient air. Furthermore, spectral line widths of ~ 10 pm have been measured at a center wavelength 424.437 nm, clearly discriminating the natural from the highly enriched uranium.« less

  8. Time-Resolved Imaging of Material Response Following Laser-Induced Breakdown in the Bulk and Surface of Fused Silica

    SciTech Connect (OSTI)

    Raman, R N; Negres, R A; DeMange, P; Demos, S G

    2010-02-04

    Optical components within high energy laser systems are susceptible to laser-induced material modification when the breakdown threshold is exceeded or damage is initiated by pre-existing impurities or defects. These modifications are the result of exposure to extreme conditions involving the generation of high temperatures and pressures and occur on a volumetric scale of the order of a few cubic microns. The response of the material following localized energy deposition, including the timeline of events and the individual processes involved during this timeline, is still largely unknown. In this work, we investigate the events taking place during the entire timeline in both bulk and surface damage in fused silica using a set of time-resolved microscopy systems. These microscope systems offer up to 1 micron spatial resolution when imaging static or dynamic effects, allowing for imaging of the entire process with adequate temporal and spatial resolution. These systems incorporate various pump-probe geometries designed to optimize the sensitivity for detecting individual aspects of the process such as the propagation of shock waves, near-surface material motion, the speed of ejecta, and material transformations. The experimental results indicate that the material response can be separated into distinct phases, some terminating within a few tens of nanoseconds but some extending up to about 100 microseconds. Overall the results demonstrate that the final characteristics of the modified region depend on the material response to the energy deposition and not on the laser parameters.

  9. Laser-induced breakdown and damage generation by nonlinear frequency conversion in ferroelectric crystals: Experiment and theory

    SciTech Connect (OSTI)

    Louchev, Oleg A.; Saito, Norihito; Wada, Satoshi; Hatano, Hideki; Kitamura, Kenji

    2013-11-28

    Using our experimental data for ns pulsed second harmonic generation (SHG) by periodically poled stoichiometric LiTaO{sub 3} (PPSLT) crystals, we consider in detail the mechanism underlying laser-induced damage in ferroelectric crystals. This mechanism involves generation and heating of free electrons, providing an effective kinetic pathway for electric breakdown and crystal damage in ns pulsed operation via combined two-photon absorption (TPA) and induced pyroelectric field. In particular, a temperature increase in the lattice of ≈1 K induced initially by ns SHG and TPA at the rear of operating PPSLT crystal is found to induce a gradient of spontaneous polarization generating a pyroelectric field of ≈10 kV/cm, accelerating free electrons generated by TPA to an energy of ≈10 eV, followed by impact ionization and crystal damage. Under the damage threshold for ns operation, the impact ionization does not lead to the avalanche-like increase of free electron density, in contrast to the case of shorter ps and fs pulses. However, the total number of collisions by free electrons, ≈10{sup 18} cm{sup −3} (generated during the pulse and accelerated to the energy of ≈10 eV), can produce widespread structural defects, which by entrapping electrons dramatically increase linear absorption for both harmonics in subsequent pulses, creating a positive feedback for crystal lattice heating, pyroelectric field and crystal damage. Under pulse repetition, defect generation starting from the rear of the crystal can propagate towards its center and front side producing damage tracks along the laser beam and stopping SHG. Theoretical analysis leads to numerical estimates and analytical approximation for the threshold laser fluence for onset of this damage mechanism, which agree well with our (i) experiments for the input 1064 nm radiation in 6.8 kHz pulsed SHG by PPSLT crystal, (ii) pulsed low frequency 532 nm radiation transmission experiments, and also (iii) with the data

  10. Time evolution studies of laser induced chemical changes in InAs nanowire using Raman spectroscopy

    SciTech Connect (OSTI)

    Pal, Suparna; Aggarwal, R.; Kumari Gupta, Vandna; Ingale, Alka

    2014-07-07

    We report the study of time evolution of chemical changes on the surface of an InAs nanowire (NW) on laser irradiation in different power density regime, using Raman spectroscopy for a time span of 8–16 min. Mixture of metastable oxides like InAsO{sub 4,} As{sub 2}O{sub 3} are formed upon oxidation, which are reflected as sharp Raman peaks at ∼240–254 and 180–200 cm{sup −1}. Evidence of removal of arsenic layer by layer is also observed at higher power density. Position controlled laser induced chemical modification on a nanometer scale, without changing the core of the NW, can be useful for NW based device fabrication.

  11. Optimally enhanced optical emission in laser-induced air plasma by femtosecond double-pulse

    SciTech Connect (OSTI)

    Chen, Anmin; Institute of Theoretical Chemistry, State Key Laboratory of Theoretical and Computational Chemistry, Jilin University, Changchun 130012 ; Li, Suyu; Li, Shuchang; Jiang, Yuanfei; Ding, Dajun; Shao, Junfeng; Wang, Tingfeng; Huang, Xuri; Jin, Mingxing; State Key Laboratory of Laser Interaction with Matter, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033

    2013-10-15

    In laser-induced breakdown spectroscopy, a femtosecond double-pulse laser was used to induce air plasma. The plasma spectroscopy was observed to lead to significant increase of the intensity and reproducibility of the optical emission signal compared to femtosecond single-pulse laser. In particular, the optical emission intensity can be optimized by adjusting the delay time of femtosecond double-pulse. An appropriate pulse-to-pulse delay was selected, that was typically about 50 ps. This effect can be especially advantageous in the context of femtosecond laser-induced breakdown spectroscopy, plasma channel, and so on.

  12. Laser-induced reactions in a deep UV resist system: Studied with picosecond infrared spectroscopy

    SciTech Connect (OSTI)

    Lippert, T.; Koskelo, A.; Stoutland, P.O.

    1995-12-31

    One of the most technologically important uses of organic photochemistry is in the imaging industry where radiation-sensitive organic monomers and polymers are used in photoresists. A widely-used class of compounds for imaging applications are diazoketones; these compounds undergo a photoinduced Wolff rearrangement to form a ketene intermediate which subsequently hydrolyses to a base-soluble, carboxylic acid. Another use of organic molecules in polymer matrices is for dopant induced ablation of polymers. As part of a program to develop diagnostics for laser driven reactions in polymer matrices, we have investigated the photoinduced decomposition of 5-diazo-2,2-dimethyl-1,3-dioxane-4,6-dione (5-diazo Meldrum`s acid, DM) in a PMMA matrix using picosecond infrared spectroscopy. In particular, irradiation of DM with a 60 ps 266 nm laser pulse results in immediate bleaching of the diazo infrared band ({nu} = 2172 cm{sup -1}). Similarly, a new band appears within our instrument response at 2161 cm{sup -1} (FWHM = 29 cm{sup -1}) and is stable to greater than 6 ns.; we assign this band to the ketene photoproduct of the Wolff rearrangement. Using deconvolution techniques we estimate a limit for its rate of formation of {tau} < 20 ps. The linear dependence of the absorbance change with the pump power (266 nm) even above the threshold of ablation suggest that material ejection take place after 6ns.

  13. Laser induced fluorescence spectroscopy of the Ca dimer deposited on helium and mixed helium/xenon clusters

    SciTech Connect (OSTI)

    Gaveau, Marc-André; Pothier, Christophe; Briant, Marc; Mestdagh, Jean-Michel

    2014-12-09

    We study how the laser induced fluorescence spectroscopy of the calcium dimer deposited on pure helium clusters is modified by the addition of xenon atoms. In the wavelength range between 365 and 385 nm, the Ca dimer is excited from its ground state up to two excited electronic states leading to its photodissociation in Ca({sup 1}P)+Ca({sup 1}S): this process is monitored by recording the Ca({sup 1}P) fluorescence at 422.7nm. One of these electronic states of Ca{sub 2} is a diexcited one correlating to the Ca(4s4p{sup 3}P(+Ca(4s3d{sup 3}D), the other one is a repulsive state correlating to the Ca(4s4p1P)+Ca(4s21S) asymptote, accounting for the dissociation of Ca{sub 2} and the observation of the subsequent Ca({sup 1}P) emission. On pure helium clusters, the fluorescence exhibits the calcium atomic resonance line Ca({sup 1}S←{sup 1}P) at 422.7 nm (23652 cm{sup −1}) assigned to ejected calcium, and a narrow red sided band corresponding to calcium that remains solvated on the helium cluster. When adding xenon atoms to the helium clusters, the intensity of these two features decreases and a new spectral band appears on the red side of calcium resonance line; the intensity and the red shift of this component increase along with the xenon quantity deposited on the helium cluster: it is assigned to the emission of Ca({sup 1}P) associated with the small xenon aggregate embedded inside the helium cluster.

  14. 4D Density Determination of NH Radicals in an MSE Microplasma Combining Planar Laser Induced Fluorescence and Cavity Ring-Down Spectroscopy

    SciTech Connect (OSTI)

    Visser, Martin; Schenk, Andreas; Gericke, Karl-Heinz

    2010-10-13

    An application of microplasmas is surface modification under mild conditions and of small, well defined areas. For this, an understanding of the plasma composition is of importance. First results of our work on the production and detection of NH radicals in a capacitively coupled radio frequency (RF) microplasma are presented. A microstructured comb electrode was used to generate a glow discharge in a hydrogen/nitrogen gas mixture by applying 13.56 MHz RF voltage. The techniques of planar laser induced fluorescence (PLIF) and cavity ring-down spectroscopy (CRDS) are used for space and time resolved, quantitative detection of the NH radical in the plasma. The rotational temperature was determined to be 820 K and, the density 5.1x10{sup 12} cm{sup 3}. Also, time dependent behaviour of the NH production was observed.

  15. Femtosecond laser-induced crystallization of amorphous Sb{sub 2}Te{sub 3} film and coherent phonon spectroscopy characterization and optical injection of electron spins

    SciTech Connect (OSTI)

    Li Simian; Huang Huan; Wang Yang; Wu Yiqun; Gan Fuxi; Zhu Weiling; Wang Wenfang; Chen Ke; Yao Daoxin; Lai Tianshu

    2011-09-01

    A femtosecond laser-irradiated crystallizing technique is tried to convert amorphous Sb{sub 2}Te{sub 3} film into crystalline film. Sensitive coherent phonon spectroscopy (CPS) is used to monitor the crystallization of amorphous Sb{sub 2}Te{sub 3} film at the original irradiation site. The CPS reveals that the vibration strength of two phonon modes that correspond to the characteristic phonon modes (A{sub 1g}{sup 1} and E{sub g}) of crystalline Sb{sub 2}Te{sub 3} enhances with increasing laser irradiation fluence (LIF), showing the rise of the degree of crystallization with LIF and that femtosecond laser irradiation is a good post-treatment technique. Time-resolved circularly polarized pump-probe spectroscopy is used to investigate electron spin relaxation dynamics of the laser-induced crystallized Sb{sub 2}Te{sub 3} film. Spin relaxation process indeed is observed, confirming the theoretical predictions on the validity of spin-dependent optical transition selection rule and the feasibility of transient spin-grating-based optical detection scheme of spin-plasmon collective modes in Sb{sub 2}Te{sub 3}-like topological insulators.

  16. Improved Laser Induced Breakdown Spectroscopy (LIBS) Elemental Composition Detection System: A device to measure subsurface gases, liquids, and solids at subsurface conditions

    Energy Innovation Portal (Marketing Summaries) [EERE]

    2016-02-23

    This device can measure subsurface gases, liquids, and solids at subsurface conditions. Atomic identification and concentration measurements can be made on solids, liquids, and gases at down hole pressure and temperature conditions....

  17. Infrared laser induced plasma diagnostics of silver target

    SciTech Connect (OSTI)

    Ahmat, L. Nadeem, Ali; Ahmed, I.

    2014-09-15

    In the present work, the optical emission spectra of silver (Ag) plasma have been recorded and analyzed using the laser induced breakdown spectroscopy technique. The emission line intensities and plasma parameters were investigated as a function of lens to sample distance, laser irradiance, and distance from the target surface. The electron number density (n{sub e}) and electron temperature (T{sub e}) were determined using the Stark broadened line profile and Boltzmann plot method, respectively. A gradual increase in the spectral line intensities and the plasma parameters, n{sub e} from 2.89 × 10{sup 17} to 3.92 × 10{sup 17 }cm{sup −3} and T{sub e} from 4662 to 8967 K, was observed as the laser irradiance was increased 2.29 × 10{sup 10}–1.06 × 10{sup 11} W cm{sup −2}. The spatial variations in n{sub e} and T{sub e} were investigated from 0 to 5.25 mm from the target surface, yielding the electron number density from 4.78 × 10{sup 17} to 1.72 × 10{sup 17 }cm{sup −3} and electron temperature as 9869–3789 K. In addition, the emission intensities and the plasma parameters of silver were investigated by varying the ambient pressure from 0.36 to 1000 mbars.

  18. Laser-induced breakdown spectroscopic study of ammonium nitrate...

    Office of Scientific and Technical Information (OSTI)

    Copyright (c) 2013 Pleiades Publishing, Ltd.; http:www.springer-ny.com; Country of input: International Atomic Energy Agency (IAEA) Country of ...

  19. Interference of atomic alkali species with laser-induced breakdown...

    Office of Scientific and Technical Information (OSTI)

    Resource Type: Journal Article Resource Relation: Journal Name: Proposed for publication in Applied Optics. Research Org: Sandia National Laboratories Sponsoring Org: USDOE Country ...

  20. Laser-induced breakdown spectroscopic study of ammonium nitrate plasma

    SciTech Connect (OSTI)

    Hanif, M.; Salik, M.; Baig, M. A.

    2013-12-15

    We present the optical emission studies of the ammonium nitrate plasma produced by the fundamental (1064 nm) and second (532 nm) harmonics of a Q-switched Nd: YAG laser. The target material was placed in front of the laser beam in an open atmospheric air. The spectrum reveals numerous transitions of neutral nitrogen. We have studied the spatial behavior of the plasma temperature (T{sub e}) and electron number density (N{sub e}) determined using the Boltzmann plot method and Stark broadened line profiles, respectively. Besides, we have studied the variation of the plasma parameters as a function of the laser irradiance.

  1. " A Heterodyne Laser-induced Fluorescence Technique to Determine...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    A Heterodyne Laser-induced Fluorescence Technique to Determine Simultaneously the Bulk ... molecule velocity distribution using a heterodyne laser induced fluorescence technique. ...

  2. Simulation of nanosecond pulsed laser ablation of copper samples: A focus on laser induced plasma radiation

    SciTech Connect (OSTI)

    Aghaei, M.; Mehrabian, S.; Tavassoli, S. H.

    2008-09-01

    A thermal model for nanosecond pulsed laser ablation of Cu in one dimension and in ambient gas, He at 1 atm, is proposed in which equations concerning heat conduction in the target and gas dynamics in the plume are solved. These equations are coupled to each other through the energy and mass balances at interface between the target and the vapor and also Knudsen layer conditions. By assumption of local thermal equilibrium, Saha-Eggert equations are used to investigate plasma formation. The shielding effect of the plasma, due to photoionization and inverse bremsstrahlung processes, is considered. Bremsstrahlung and blackbody radiation and spectral emissions of the plasma are also investigated. Spatial and temporal distribution of the target temperature, number densities of Cu and He, pressure and temperature of the plume, bremsstrahlung and blackbody radiation, and also spectral emissions of Cu at three wavelengths (510, 516, and 521 nm) are obtained. Results show that the spectral power of Cu lines has the same pattern as CuI relative intensities from National Institute of Standard and Technology. Investigation of spatially integrated bremsstrahlung and blackbody radiation, and also Cu spectral emissions indicates that although in early times the bremsstrahlung radiation dominates the two other radiations, the Copper spectral emission is the dominant radiation in later times. It should be mentioned that the blackbody radiation has the least values in both time intervals. The results can be used for prediction of the optimum time and position of the spectral line emission, which is applicable in some time resolved spectroscopic techniques such as laser induced breakdown spectroscopy. Furthermore, the results suggest that for distinguishing between the spectral emission and the bremsstrahlung radiation, a spatially resolved spectroscopy can be used instead of the time resolved one.

  3. High resolution analysis of soil elements with laser-induced breakdown

    DOE Patents [OSTI]

    Ebinger, Michael H.; Harris, Ronny D.

    2010-04-06

    The invention is a system and method of detecting a concentration of an element in a soil sample wherein an opening or slot is formed in a container that supports a soil sample that was extracted from the ground whereupon at least a length of the soil sample is exposed via the opening. At each of a plurality of points along the exposed length thereof, the soil sample is ablated whereupon a plasma is formed that emits light characteristic of the elemental composition of the ablated soil sample. Each instance of emitted light is separated according to its wavelength and for at least one of the wavelengths a corresponding data value related to the intensity of the light is determined. As a function of each data value a concentration of an element at the corresponding point along the length of the soil core sample is determined.

  4. Method of molecular specie alteration by nonresonant laser induced dielectric breakdown

    DOE Patents [OSTI]

    Ronn, Avigdor M.

    1980-01-01

    Irradiation of a molecular specie by itself or in the presence of a secondary material at a pressure above a threshold value for the particular system by a laser of predetermined minimum power and having a frequency displaced from an absorption line of the specie causes severance of the weakest bond and a yield of products containing at least one dissociative fragment from said specie. A Rogowski type TEA CO.sub.2 --N.sub.2 --He laser has been used successfully on a wide variety of molecular species. Solid, liquid and gaseous end products have been obtained depending upon the starting materials. When solids have been produced they are in the form of microfine particles or microfine aggregates. A neodymium glass laser has also been used successfully.

  5. Laser-induced differential normalized fluorescence method for cancer diagnosis

    DOE Patents [OSTI]

    Vo-Dinh, Tuan; Panjehpour, Masoud; Overholt, Bergein F.

    1996-01-01

    An apparatus and method for cancer diagnosis are disclosed. The diagnostic method includes the steps of irradiating a tissue sample with monochromatic excitation light, producing a laser-induced fluorescence spectrum from emission radiation generated by interaction of the excitation light with the tissue sample, and dividing the intensity at each wavelength of the laser-induced fluorescence spectrum by the integrated area under the laser-induced fluorescence spectrum to produce a normalized spectrum. A mathematical difference between the normalized spectrum and an average value of a reference set of normalized spectra which correspond to normal tissues is calculated, which provides for amplifying small changes in weak signals from malignant tissues for improved analysis. The calculated differential normalized spectrum is correlated to a specific condition of a tissue sample.

  6. Laser-induced differential normalized fluorescence method for cancer diagnosis

    DOE Patents [OSTI]

    Vo-Dinh, T.; Panjehpour, M.; Overholt, B.F.

    1996-12-03

    An apparatus and method for cancer diagnosis are disclosed. The diagnostic method includes the steps of irradiating a tissue sample with monochromatic excitation light, producing a laser-induced fluorescence spectrum from emission radiation generated by interaction of the excitation light with the tissue sample, and dividing the intensity at each wavelength of the laser-induced fluorescence spectrum by the integrated area under the laser-induced fluorescence spectrum to produce a normalized spectrum. A mathematical difference between the normalized spectrum and an average value of a reference set of normalized spectra which correspond to normal tissues is calculated, which provides for amplifying small changes in weak signals from malignant tissues for improved analysis. The calculated differential normalized spectrum is correlated to a specific condition of a tissue sample. 5 figs.

  7. Crystal structure of laser-induced subsurface modifications in Si

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Verburg, P. C.; Smillie, L. A.; Römer, G. R. B. E.; Haberl, B.; Bradby, J. E.; Williams, J. S.; Huis in ’t Veld, A. J.

    2015-06-04

    Laser-induced subsurface modification of dielectric materials is a well-known technology. Applications include the production of optical components and selective etching. In addition to dielectric materials, the subsurface modification technology can be applied to silicon, by employing near to mid-infrared radiation. An application of subsurface modifications in silicon is laser-induced subsurface separation, which is a method to separate wafers into individual dies. Other applications for which proofs of concept exist are the formation of waveguides and resistivity tuning. However, limited knowledge is available about the crystal structure of subsurface modifications in silicon. In this paper, we investigate the geometry and crystalmore » structure of laser-induced subsurface modifications in monocrystalline silicon wafers. Finally, in addition to the generation of lattice defects, we found that transformations to amorphous silicon and Si-iii/Si-xii occur as a result of the laser irradiation.« less

  8. Crystal structure of laser-induced subsurface modifications in Si

    SciTech Connect (OSTI)

    Verburg, P. C.; Smillie, L. A.; Römer, G. R. B. E.; Haberl, B.; Bradby, J. E.; Williams, J. S.; Huis in ’t Veld, A. J.

    2015-06-04

    Laser-induced subsurface modification of dielectric materials is a well-known technology. Applications include the production of optical components and selective etching. In addition to dielectric materials, the subsurface modification technology can be applied to silicon, by employing near to mid-infrared radiation. An application of subsurface modifications in silicon is laser-induced subsurface separation, which is a method to separate wafers into individual dies. Other applications for which proofs of concept exist are the formation of waveguides and resistivity tuning. However, limited knowledge is available about the crystal structure of subsurface modifications in silicon. In this paper, we investigate the geometry and crystal structure of laser-induced subsurface modifications in monocrystalline silicon wafers. Finally, in addition to the generation of lattice defects, we found that transformations to amorphous silicon and Si-iii/Si-xii occur as a result of the laser irradiation.

  9. Investigating the dynamics of laser induced sparks in atmospheric helium using Rayleigh and Thomson scattering

    SciTech Connect (OSTI)

    Nedanovska, E.; Nersisyan, G.; Lewis, C. L. S.; Riley, D.; Graham, W. G.; Morgan, T. J.; Hüwel, L.; Murakami, T.

    2015-01-07

    We have used optical Rayleigh and Thomson scattering to investigate the expansion dynamics of laser induced plasma in atmospheric helium and to map its electron parameters both in time and space. The plasma is created using 9 ns duration, 140 mJ pulses from a Nd:YAG laser operating at 1064 nm, focused with a 10 cm focal length lens, and probed with 7 ns, 80 mJ, and 532 nm Nd:YAG laser pulses. Between 0.4 μs and 22.5 μs after breakdown, the electron density decreases from 3.3 × 10{sup 17 }cm{sup −3} to 9 × 10{sup 13 }cm{sup −3}, while the temperature drops from 3.2 eV to 0.1 eV. Spatially resolved Thomson scattering data recorded up to 17.5 μs reveal that during this time the laser induced plasma expands at a rate given by R ∼ t{sup 0.4} consistent with a non-radiative spherical blast wave. This data also indicate the development of a toroidal structure in the lateral profile of both electron temperature and density. Rayleigh scattering data show that the gas density decreases in the center of the expanding plasma with a central scattering peak reemerging after about 12 μs. We have utilized a zero dimensional kinetic global model to identify the dominant particle species versus delay time and this indicates that metastable helium and the He{sub 2}{sup +} molecular ion play an important role.

  10. Wavelength dependence of femtosecond laser-induced damage threshold of optical materials

    SciTech Connect (OSTI)

    Gallais, L. Douti, D.-B.; Commandré, M.; Batavičiūtė, G.; Pupka, E.; Ščiuka, M.; Smalakys, L.; Sirutkaitis, V.; Melninkaitis, A.

    2015-06-14

    An experimental and numerical study of the laser-induced damage of the surface of optical material in the femtosecond regime is presented. The objective of this work is to investigate the different processes involved as a function of the ratio of photon to bandgap energies and compare the results to models based on nonlinear ionization processes. Experimentally, the laser-induced damage threshold of optical materials has been studied in a range of wavelengths from 1030 nm (1.2 eV) to 310 nm (4 eV) with pulse durations of 100 fs with the use of an optical parametric amplifier system. Semi-conductors and dielectrics materials, in bulk or thin film forms, in a range of bandgap from 1 to 10 eV have been tested in order to investigate the scaling of the femtosecond laser damage threshold with the bandgap and photon energy. A model based on the Keldysh photo-ionization theory and the description of impact ionization by a multiple-rate-equation system is used to explain the dependence of laser-breakdown with the photon energy. The calculated damage fluence threshold is found to be consistent with experimental results. From these results, the relative importance of the ionization processes can be derived depending on material properties and irradiation conditions. Moreover, the observed damage morphologies can be described within the framework of the model by taking into account the dynamics of energy deposition with one dimensional propagation simulations in the excited material and thermodynamical considerations.

  11. Supersonic laser-induced jetting of aluminum micro-droplets

    SciTech Connect (OSTI)

    Zenou, M.; Sa'ar, A.; Kotler, Z.

    2015-05-04

    The droplet velocity and the incubation time of pure aluminum micro-droplets, printed using the method of sub-nanosecond laser induced forward transfer, have been measured indicating the formation of supersonic laser-induced jetting. The incubation time and the droplet velocity were extracted by measuring a transient electrical signal associated with droplet landing on the surface of the acceptor substrate. This technique has been exploited for studying small volume droplets, in the range of 10–100 femto-litters for which supersonic velocities were measured. The results suggest elastic propagation of the droplets across the donor-to-acceptor gap, a nonlinear deposition dynamics on the surface of the acceptor and overall efficient energy transfer from the laser beam to the droplets.

  12. Ultratrace analysis of transuranic actinides by laser-induced fluorescence

    DOE Patents [OSTI]

    Miller, S.M.

    1983-10-31

    Ultratrace quantities of transuranic actinides are detected indirectly by their effect on the fluorescent emissions of a preselected fluorescent species. Transuranic actinides in a sample are coprecipitated with a host lattice material containing at least one preselected fluorescent species. The actinide either quenches or enhances the laser-induced fluorescence of the preselected fluorescent species. The degree of enhancement or quenching is quantitatively related to the concentration of actinide in the sample.

  13. Ultratrace analysis of transuranic actinides by laser-induced fluorescence

    DOE Patents [OSTI]

    Miller, Steven M.

    1988-01-01

    Ultratrace quantities of transuranic actinides are detected indirectly by their effect on the fluorescent emissions of a preselected fluorescent species. Transuranic actinides in a sample are coprecipitated with a host lattice material containing at least one preselected fluorescent species. The actinide either quenches or enhances the laser-induced fluorescence of the preselected fluorescent species. The degree of enhancement or quenching is quantitatively related to the concentration of actinide in the sample.

  14. Module 2- Work Breakdown Structure

    Broader source: Energy.gov [DOE]

    This module defines and illustrates the Work Breakdown Structure (WBS), WBS dictionary, Organizational Breakdown Structure (OBS) and Responsibility Assignment Matrix (RAM).

  15. Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy Spectroscopy Print In spectroscopy experiments, a sample is illuminated with light and the various product particles (electrons, ions, or fluorescent photons) are detected and analyzed.The unifying feature is that some "property" of a material is measured as the x-ray (photon) energy is swept though a range of values. At the most basic level, one measures the absorption, transmission, or reflectivity of a sample as a function of photon energy. Probes that use the vacuum

  16. SAGE mission to Venus

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Raman spectroscopy and Laser-Induced Breakdown Spectroscopy will both be used on the SAGE lander, providing multiple measurements of the planet's surface and subsurface. Since the ...

  17. Interaction between jets during laser-induced forward transfer

    SciTech Connect (OSTI)

    Patrascioiu, A.; Florian, C.; Fernndez-Pradas, J. M.; Morenza, J. L.; Serra, P.; Hennig, G.; Delaporte, P.

    2014-07-07

    Simultaneous two-beam laser-induced forward transfer (LIFT) was carried out for various inter-beam separations, analyzing both the resulting printing outcomes and the corresponding liquid transfer dynamics. In a first experiment, droplets of an aqueous solution were printed onto a substrate at different inter-beam distances, which proved that a significant departure from the single-beam LIFT dynamics takes places at specific separations. In the second experiment, time-resolved imaging analysis revealed the existence of significant jet-jet interactions at those separations; such interactions proceed through a dynamics that results in remarkable jet deflection for which a possible onset mechanism is proposed.

  18. Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Spectroscopy Print In spectroscopy experiments, a sample is illuminated with light and the various product particles (electrons, ions, or fluorescent photons) are detected and analyzed.The unifying feature is that some "property" of a material is measured as the x-ray (photon) energy is swept though a range of values. At the most basic level, one measures the absorption, transmission, or reflectivity of a sample as a function of photon energy. Probes that use the vacuum ultraviolet

  19. Laser induced extraplanar propulsion for three-dimensional microfabrication

    SciTech Connect (OSTI)

    Birnbaum, A. J.; Pique, A.

    2011-03-28

    The laser induced extraplanar propulsion process is presented for the creation of controllable three-dimensional deformation of on-substrate components. It is demonstrated that the process is compatible with transparent substrates and ductile materials and is highly controllable in terms of the desired deformation via the adjustment of incident laser energy density. Copper films with thicknesses varying from 0.1-1 {mu}m are deformed over bending angles ranging from 0 deg. - 180 deg. A 355 nm laser at fluences ranging from 10-40 mJ/cm{sup 2} is used in conjunction with an indium-tin-oxide propulsion layer to demonstrate the process. Characterization is performed via electron and laser confocal microscopy.

  20. Ultrafast laser induced periodic sub-wavelength aluminum surface structures and nanoparticles in air and liquids

    SciTech Connect (OSTI)

    Kuladeep, Rajamudili; Dar, Mudasir H.; Rao, D. Narayana E-mail: dnr-laserlab@yahoo.com; Deepak, K. L. N.

    2014-09-21

    In this communication, we demonstrate the generation of laser-induced periodic sub-wavelength surface structures (LIPSS) or ripples on a bulk aluminum (Al) and Al nanoparticles (NPs) by femtosecond (fs) laser direct writing technique. Laser irradiation was performed on Al surface at normal incidence in air and by immersing in ethanol (C₂H₅OH) and water (H₂O) using linearly polarized Ti:sapphire fs laser pulses of ~110 fs pulse duration and ~800 nm wavelength. Field emission scanning electron microscope is utilized for imaging surface morphology of laser written structures and it reveals that the spatial periodicity as well as the surface morphology of the LIPSS depends on the surrounding dielectric medium and also on the various laser irradiation parameters. The observed LIPSS have been classified as low spatial frequency LIPSS which are perpendicularly oriented to the laser polarization with a periodicity from 460 to 620 nm and high spatial frequency LIPSS which spectacles a periodicity less than 100 nm with the orientation parallel to the polarization of the incident laser beam. Fabricated colloidal solutions, which contain the Al NPs, were characterized by UV-Vis absorption spectroscopy and transmission electron microscopy (TEM). TEM results reveal the formation of internal cavities in Al NPs both in ethanol and water. Formation mechanism of LIPSS and cavities inside the nanoparticles are discussed in detail.

  1. Confinement effects of shock waves on laser-induced plasma from a graphite target

    SciTech Connect (OSTI)

    Huang, Feiling; Liang, Peipei; Yang, Xu; Cai, Hua; Wu, Jiada; Xu, Ning; Ying, Zhifeng; Sun, Jian

    2015-06-15

    The spatial confinement effects of shock waves on the laser-induced plasma (LIP) from a graphite target in air were studied by probe beam deflection (PBD) measurements and optical emission spectroscopy (OES). A clear relationship between the confinement of the LIP by the shock wave and the effects on the LIP emission was observed, and the underlying mechanisms are discussed. PBD monitoring revealed that the laser-ablation induced shock wave could be well analogized to the shock wave generated by a point explosion and would be reflected by a block. OES measurements indicated that the optical emission of the LIP exhibited significant variations with the block placement. A first enhancement and then a fast decay of CN molecular emission as well as a suppression of carbon atomic emission were observed in the presence of the block. The results revealed that the reflected shock wave spatially confined the expansion of the LIP and compressed the LIP after encountering it, pushing back the species of the LIP and changing the density of the LIP species including luminous carbon atoms and CN molecules. It is suggested that the change of the LIP emission is attributed to the density variation of the LIP species due to the compression of the LIP and the reactions occurring in the plasma.

  2. DOE Announces $16 Million for 54 Projects to Help Commercialize...

    Broader source: Energy.gov (indexed) [DOE]

    ... Louisville, KY Laser Induced Breakdown Spectroscopy (LIBS) Subsurface Sensor Maturation, 246,423: Applied Spectra, Inc., Fremont, CA. Raman Gas Analyzer Cooperative Development, ...

  3. Evaluation of alkali concentration in conditions relevant to...

    Office of Scientific and Technical Information (OSTI)

    Conference: Evaluation of alkali concentration in conditions relevant to oxygennatural gas glass furnaces by laser-induced breakdown spectroscopy. Citation Details In-Document ...

  4. Laser induced focusing for over-dense plasma beams

    SciTech Connect (OSTI)

    Schmidt, Peter; Boine-Frankenheim, Oliver; Mulser, Peter

    2015-09-15

    The capability of ion acceleration with high power, pulsed lasers has become an active field of research in the past years. In this context, the radiation pressure acceleration (RPA) mechanism has been the topic of numerous theoretical and experimental publications. Within that mechanism, a high power, pulsed laser beam hits a thin film target. In contrast to the target normal sheath acceleration, the entire film target is accelerated as a bulk by the radiation pressure of the laser. Simulations predict heavy ion beams with kinetic energy up to GeV, as well as solid body densities. However, there are several effects which limit the efficiency of the RPA: On the one hand, the Rayleigh-Taylor-instability limits the predicted density. On the other hand, conventional accelerator elements, such as magnetic focusing devices are too bulky to be installed right after the target. Therefore, we present a new beam transport method, suitable for RPA-like/over-dense plasma beams: laser induced focusing.

  5. Efficient laser-induced 6 - 8 keV x-ray production from iron...

    Office of Scientific and Technical Information (OSTI)

    Journal Article: Efficient laser-induced 6 - 8 keV x-ray production from iron oxide aerogel and foil-lined cavity targets Citation Details In-Document Search Title: Efficient ...

  6. Laser Induced Nuclear Fusion, LINF, In Muonic Molecules With Ultrashort Super Intense Laser Fields

    SciTech Connect (OSTI)

    Bandrauk, Andre D.; Paramonov, Gennady K.

    2010-02-02

    Muonium molecules where muons replace electrons increase the stability of molecules to ionization at superhigh intensities, I>10{sup 20} W/cm{sup 2}. We show furthermore from numerical simulations that in the nonsymmetric series, pdu, dtu, ptu, the permanent dipole moments can be used to enhance LINF, Laser Induced Nuclear Fusion by laser induced recollision of the light nucleus with the heavier nucleus.

  7. Laser-induced periodic annular surface structures on fused silica surface

    SciTech Connect (OSTI)

    Liu, Yi; Brelet, Yohann; Forestier, Benjamin; Houard, Aurelien; Yu, Linwei; Deng, Yongkai; Jiang, Hongbing

    2013-06-24

    We report on the formation of laser-induced periodic annular surface structures on fused silica irradiated with multiple femtosecond laser pulses. This surface morphology emerges after the disappearance of the conventional laser induced periodic surface structures, under successive laser pulse irradiation. It is independent of the laser polarization and universally observed for different focusing geometries. We interpret its formation in terms of the interference between the reflected laser field on the surface of the damage crater and the incident laser pulse.

  8. Characterization Of High Explosives Detonations Via Laser-Induced Plasmas

    SciTech Connect (OSTI)

    Villa-Aleman, E.

    2015-10-08

    One objective of the Department of Energy’s National Security Administration is to develop technologies that can help the United States government to detect foreign nuclear weapons development activities. The realm of high explosive (HE) experiments is one of the key areas to assess the nuclear ambitions of a country. SRNL has participated in the collection of particulates from HE experiments and characterized the material with the purpose to correlate particulate matter with HE. Since these field campaigns are expensive, on-demand simulated laboratory-scale explosion experiments are needed to further our knowledge of the chemistry and particle formation in the process. Our goal is to develop an experimental test bed in the laboratory to test measurement concepts and correlate particle formation processes with the observables from the detonation fireball. The final objective is to use this knowledge to tailor our experimental setups in future field campaigns. The test bed uses pulsed laser-induced plasmas to simulate micro-explosions, with the intent to study the temporal behavior of the fireball observed in field tests. During FY15, a plan was prepared and executed which assembled two laser ablation systems, procured materials for study, and tested a Step-Scan Fourier Transform Infrared Spectrometer (SS-FTIR). Designs for a shadowgraph system for shock wave analysis, design for a micro-particulate collector from ablated pulse were accomplished. A novel spectroscopic system was conceived and a prototype system built for acquisition of spectral/temporal characterization of a high speed event such as from a high explosive detonation. Experiments and analyses will continue into FY16.

  9. Fundamental studies of passivity and passivity breakdown. Final report, [September 1993--September 1994

    SciTech Connect (OSTI)

    Macdonald, D.D.; Urquidi-Macdonald, M.

    1994-02-21

    Purpose is to understand the mechanisms for growth and breakdown of passive films on metal and alloy surfaces in aqueous medium; a secondary goal is to devise methods for predicting localized corrosion damage in industrial systems. Tasks currently being studied are: formation of bilayer structures in passive films on metals and alloys; passivity breakdown on solid vs. liquid gallium; roles of alloying elements in passivity breakdown; electrochemical impedance spectroscopy of passive films; electronic structure of passive oxide films; photoelectrochemical impedance spectroscopy of passive films; and kinetics of localized attack.

  10. RF breakdown experiments at SLAC

    SciTech Connect (OSTI)

    Laurent, L. [University of California Davis, Davis, California 95616 (United States); Vlieks, A.; Pearson, C.; Caryotakis, G.; Luhmann, N.C. [Stanford Linear Accelerator Center, Menlo Park, California 94025 (United States)

    1999-05-01

    RF breakdown is a critical issue in the conditioning of klystrons, accelerator sections, and rf components for the next linear collider (NLC), as well as other high gradient accelerators and high power microwave sources. SLAC is conducting a series of experiments using an X-band traveling wave ring to characterize the processes and trigger mechanisms associated with rf breakdown. The goal of the research is to identify materials, processes, and manufacturing methods that will increase the breakdown threshold and minimize the time required for conditioning. {copyright} {ital 1999 American Institute of Physics.}

  11. Laser-induced light emission from carbon nanoparticles

    SciTech Connect (OSTI)

    Osswald, S.; Behler, K.; Gogotsi, Y.

    2008-10-01

    Strong absorption of light in a broad wavelength range and poor thermal conductance between particles of carbon nanomaterials, such as nanotubes, onions, nanodiamond, and carbon black, lead to strong thermal emission (blackbody radiation) upon laser excitation, even at a very low (milliwatts) power. The lasers commonly used during Raman spectroscopy characterization of carbon can cause sample heating to very high temperatures. While conventional thermometry is difficult in the case of nanomaterials, Raman spectral features, such as the G band of graphitic carbon and thermal emission spectra were used to estimate the temperature during light emission that led to extensive graphitization and evaporation of carbon nanomaterials, indicating local temperatures exceeding 3500 deg. C.

  12. Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

    DOE Patents [OSTI]

    Yeung, Edward S.; Kuhr, Werner G.

    1996-02-20

    A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

  13. Means and method for capillary zone electrophoresis with laser-induced indirect fluorescence detection

    DOE Patents [OSTI]

    Yeung, Edwards; Kuhr, Werner G.

    1991-04-09

    A means and method for capillary zone electrphoresis with laser-induced indirect fluorescence detection. A detector is positioned on the capillary tube of a capillary zone electrophoresis system. The detector includes a laser which generates a laser beam which is imposed upon a small portion of the capillary tube. Fluorescence of the elutant electromigrating through the capillary tube is indirectly detected and recorded.

  14. Laser induced plasma on copper target, a non-equilibrium model

    SciTech Connect (OSTI)

    Oumeziane, Amina Ait Liani, Bachir; Parisse, Jean-Denis

    2014-02-15

    The aim of this work is to present a comprehensive numerical model for the UV laser ablation of metal targets, it focuses mainly on the prediction of laser induced plasma thresholds, the effect of the laser-plasma interaction, and the importance of the electronic non-equilibrium in the laser induced plume and its expansion in the background gas. This paper describes a set of numerical models for laser-matter interaction between 193-248 and 355 nm lasers and a copper target. Along with the thermal effects inside the material resulting from the irradiation of the latter with the pulsed laser, the laser-evaporated matter interaction and the plasma formation are thoroughly modelled. In the laser induced plume, the electronic nonequilibrium and the laser beam absorption have been investigated. Our calculations of the plasmas ignition thresholds on copper targets have been validated and compared to experimental as well as theoretical results. Comparison with experiment data indicates that our results are in good agreement with those reported in the literature. Furthermore, the inclusion of electronic non-equilibrium in our work indicated that this important process must be included in models of laser ablation and plasma plume formation.

  15. Microsoft PowerPoint - BackeSHE2015LaserSpectroscopy [Kompatibilitätsmodus]

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laser Spectroscopy of Superheavy Elements Hartmut Backe 1 , Michael Block, Mustapha Laatiaoui, Werner Lauth 1 University of Mainz, Germany International Symposium Super Heavy Nuclei 2015, Texas A&M University, College Station, Texas, USA, March 31 - April 02, 2015 Outline 1. Introduction and Motivation 2. How Sensitive is Optical Spectroscopy? 3. Remarks on Laser Induced Fluorescence (LIF) Spectroscopy in a Buffer Gas Trap 4. RAdioactive Decay Detected Resonance Ionization Spectroscopy

  16. Cooperative effect of ultraviolet and near-infrared beams in laser-induced condensation

    SciTech Connect (OSTI)

    Matthews, M.; Henin, S.; Pomel, F.; Kasparian, J.; Wolf, J.-P.; Thberge, F.; Daigle, J.-F.; Lassonde, P.; Kieffer, J.-C.

    2013-12-23

    We demonstrate the cooperative effect of near infrared (NIR) and ultraviolet (UV) beams on laser-induced condensation. Launching a UV laser after a NIR pulse yields up to a 5-fold increase in the production of nanoparticles (25300 nm) as compared to a single NIR beam. This cooperative effect exceeds the sum of those from the individual beams and occurs for delays up to 1 ?s. We attribute it to the UV photolysis of ozone created by the NIR pulses. The resulting OH radicals oxidize NO{sub 2} and volatile organic compounds, producing condensable species.

  17. Temporal evolution of femtosecond laser induced plasma filament in air and N{sub 2}

    SciTech Connect (OSTI)

    Papeer, J.; Botton, M.; Zigler, A.; Gordon, D.; Sprangle, P.

    2013-12-09

    We present single shot, high resolution, time-resolved measurements of the relaxation of laser induced plasma filaments in air and in N{sub 2} gas. Based on the measurements of the time dependent electromagnetic signal in a waveguide, an accurate and simple derivation of the electron density in the filament is demonstrated. This experimental method does not require prior knowledge of filament dimensions or control over its exact spatial location. The experimental results are compared to numerical simulations of air plasma chemistry. Results reveal the role of various decay mechanisms including the importance of O{sub 4}{sup +} molecular levels.

  18. Quantitative characterization of a nonreacting, supersonic combustor flowfield using unified, laser-induced iodine fluorescence

    SciTech Connect (OSTI)

    Fletcher, D.G.; McDaniel, J.C.

    1989-01-01

    A calibrated, nonintrusive optical technique, laser-induced iodine fluorescence (LIIF) was used to quantify the steady, compressible flowfield of a nonreacting, supersonic combustor. The combustor was configured with single and staged, transverse-air injection into a supersonic-air freestream behind a rearward-facing step. Pressure, temperature, two-velocity components, and injectant mole fraction were measured with high spatial resolution in the three-dimensional flowfields. These experimental results provide a benchmark set of data for validation of computational fluid dynamic (CFD) codes being developed to model supersonic combustor flowfields. 8 refs.

  19. Resonant- and avalanche-ionization amplification of laser-induced plasma in air

    SciTech Connect (OSTI)

    Wu, Yue; Zhang, Zhili; Jiang, Naibo; Roy, Sukesh; Gord, James R.

    2014-10-14

    Amplification of laser-induced plasma in air is demonstrated utilizing resonant laser ionization and avalanche ionization. Molecular oxygen in air is ionized by a low-energy laser pulse employing (2 + 1) resonance-enhanced multi-photon ionization (REMPI) to generate seed electrons. Subsequent avalanche ionization of molecular oxygen and nitrogen significantly amplifies the laser-induced plasma. In this plasma-amplification effect, three-body attachments to molecular oxygen dominate the electron-generation and -loss processes, while either nitrogen or argon acts as the third body with low electron affinity. Contour maps of the electron density within the plasma obtained in O₂/N₂ and O₂/Ar gas mixtures are provided to show relative degrees of plasma amplification with respect to gas pressure and to verify that the seed electrons generated by O₂ 2 + 1 REMPI are selectively amplified by avalanche ionization of molecular nitrogen in a relatively low-pressure condition (≤100 Torr). Such plasma amplification occurring in air could be useful in aerospace applications at high altitude.

  20. Breakdown properties of irradiated MOS capacitors

    SciTech Connect (OSTI)

    Paccagnella, A.; Candelori, A.; Milani, A.; Formigoni, E.; Ghidini, G.; Drera, D.; Pellizzer, F.; Fuochi, P.G.; Lavale, M.

    1996-12-01

    The authors have studied the effects of ionizing and non-ionizing radiation on the breakdown properties of different types of MOS capacitors, with thick (200 nm) and thin (down to 8 nm) oxides. In general, no large variations of the average breakdown field, time-to-breakdown at constant voltage, or charge-to-breakdown at constant voltage, or charge-to-breakdown values have been observed after high dose irradiation (20 Mrad(Si) 9 MeV electrons on thin and thick oxides, 17(Si) Mrad Co{sup 60} gamma and 10{sup 14} neutrons/cm{sup 2} only on thick oxides). However, some modifications of the cumulative failure distributions have been observed in few of the oxides tested.

  1. Reconstruction of two-dimensional molecular structure with laser-induced electron diffraction from laser-aligned polyatomic molecules

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Yu, Chao; Wei, Hui; Wang, Xu; Le, Anh -Thu; Lu, Ruifeng; Lin, C. D.

    2015-10-27

    Imaging the transient process of molecules has been a basic way to investigate photochemical reactions and dynamics. Based on laser-induced electron diffraction and partial one-dimensional molecular alignment, here we provide two effective methods for reconstructing two-dimensional structure of polyatomic molecules. We demonstrate that electron diffraction images in both scattering angles and broadband energy can be utilized to retrieve complementary structure information, including positions of light atoms. Lastly, with picometre spatial resolution and the inherent femtosecond temporal resolution of lasers, laser-induced electron diffraction method offers significant opportunities for probing atomic motion in a large molecule in a typical pump-probe measurement.

  2. Mitigating Breakdown in High Energy Density Perovskite Polymer...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Mitigating Breakdown in High Energy Density Perovskite Polymer Nanocomposite Capacitors Mitigating Breakdown in High Energy Density Perovskite Polymer Nanocomposite Capacitors 2012 ...

  3. Kondo Breakdown in Topological Kondo Insulators (Journal Article...

    Office of Scientific and Technical Information (OSTI)

    Kondo Breakdown in Topological Kondo Insulators Prev Next Title: Kondo Breakdown in Topological Kondo Insulators Authors: Alexandrov, Victor ; Coleman, Piers ; Erten, Onur ...

  4. [Fundamental studies of passivity and passivity breakdown

    SciTech Connect (OSTI)

    Macdonald, D.D.

    1993-07-01

    We developed and experimentally tested physical models for growth and breakdown of passive films on metal surfaces. These models are ``point defect models,`` in which the growth and breakdown are described in terms of movement of anion and cation vacancies. The work during the past 5 years resulted in: theory of growth and breakdown of passive films, theory of corrosion-resistant alloys, electronic structure of passive films, and estimation of damage functions for energy systems. Proposals are give for the five ongoing tasks. 10 figs.

  5. Nanoscale Laser-Induced Spallation in SiO2 Films Containing Gold Nanoparticles

    SciTech Connect (OSTI)

    Kudryashov, S.I.; Allen, S.D.; Papernov, S.; Schmid, A.W.

    2006-02-16

    A phenomenological theory of ultraviolet pulsed-laser-induced spallation is proposed to interpret crater formation in SiO2 thin films containing absorbing 18.5-nm gold particles. The theory considers a spherical thermoacoustic stress wave propagating from a thermal source produced by laser-energy absorption inside the particle and surrounding ionized volume. Calculations show that the tensile stress associated with such an acoustic wave may exceed the local strength of the material and cause fracture and spallation of the top film portion. The theory provides an explanation of the experimentally observed complex (two-cone) shape of craters formed in the film with particle-lodging depth exceeding 110 nm. Theoretical estimates for the threshold stress amplitude and peak temperature in the thermal source are in qualitative agreement with the experimental observations.

  6. Properties of laser radiation scattering by a laser-induced spark plasma revisited after 40 years

    SciTech Connect (OSTI)

    Malyutin, A A

    2008-05-31

    Experimental studies of a laser-induced spark produced in air by 1.05-{mu}m, 100-ns pulses with spatial TEM{sub 00}, TEM{sub 01} and TEM{sub 02} modes are described. It is found that when the spark is observed at an angle of 90{sup 0} to the laser beam axis, the scattered radiation has the maximal intensity outside the beam waist. The intensity ratio of the scattered laser radiation for two orthogonal polarisations is {approx}100, and the spatial structures of their depolarisation considerably differ. These properties are explained by using a model of the Fresnel reflection from the spherical front of the plasma-undisturbed gas interface. (laser radiation scattering)

  7. Light scattering from laser induced pit ensembles on high power laser optics

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Feigenbaum, Eyal; Elhadj, Selim; Matthews, Manyalibo J.

    2015-01-01

    Far-field light scattering characteristics from randomly arranged shallow Gaussian-like shaped laser induced pits, found on optics exposed to high energy laser pulses, is studied. Closed-form expressions for the far-field intensity distribution and scattered power are derived for individual pits and validated using numerical calculations of both Fourier optics and FDTD solutions to Maxwells equations. It is found that the scattered power is proportional to the square of the pit width and approximately also to the square of the pit depth, with the proportionality factor scaling with pit depth. As a result, the power scattered from shallow pitted optics is expectedmoreto be substantially lower than assuming complete scattering from the total visible footprint of the pits.less

  8. Higher certainty of the laser-induced damage threshold test with a redistributing data treatment

    SciTech Connect (OSTI)

    Jensen, Lars; Mrohs, Marius; Gyamfi, Mark; Mädebach, Heinrich; Ristau, Detlev

    2015-10-15

    As a consequence of its statistical nature, the measurement of the laser-induced damage threshold holds always risks to over- or underestimate the real threshold value. As one of the established measurement procedures, the results of S-on-1 (and 1-on-1) tests outlined in the corresponding ISO standard 21 254 depend on the amount of data points and their distribution over the fluence scale. With the limited space on a test sample as well as the requirements on test site separation and beam sizes, the amount of data from one test is restricted. This paper reports on a way to treat damage test data in order to reduce the statistical error and therefore measurement uncertainty. Three simple assumptions allow for the assignment of one data point to multiple data bins and therefore virtually increase the available data base.

  9. Initiation time of near-infrared laser-induced slip on the surface of silicon wafers

    SciTech Connect (OSTI)

    Choi, Sungho; Jhang, Kyung-Young

    2014-06-23

    We have determined the initiation time of laser-induced slip on a silicon wafer surface subjected to a near-infrared continuous-wave laser by numerical simulations and experiments. First, numerical analysis was performed based on the heat transfer and thermoelasticity model to calculate the resolved shear stress and the temperature-dependent yield stress. Slip initiation time was predicted by finding the time at which the resolved shear stress reached the yield stress. Experimentally, the slip initiation time was measured by using a laser scattering technique that collects scattered light from the silicon wafer surface and detects strong scattering when the surface slip is initiated. The surface morphology of the silicon wafer surface after laser irradiation was also observed using an optical microscope to confirm the occurrence of slip. The measured slip initiation times agreed well with the numerical predictions.

  10. Modeling laser-induced periodic surface structures: Finite-difference time-domain feedback simulations

    SciTech Connect (OSTI)

    Skolski, J. Z. P. Vincenc Obona, J.; Römer, G. R. B. E.; Huis in 't Veld, A. J.

    2014-03-14

    A model predicting the formation of laser-induced periodic surface structures (LIPSSs) is presented. That is, the finite-difference time domain method is used to study the interaction of electromagnetic fields with rough surfaces. In this approach, the rough surface is modified by “ablation after each laser pulse,” according to the absorbed energy profile, in order to account for inter-pulse feedback mechanisms. LIPSSs with a periodicity significantly smaller than the laser wavelength are found to “grow” either parallel or orthogonal to the laser polarization. The change in orientation and periodicity follow from the model. LIPSSs with a periodicity larger than the wavelength of the laser radiation and complex superimposed LIPSS patterns are also predicted by the model.

  11. Measurement of optical scattered power from laser-induced shallow pits on silica

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Feigenbaum, Eyal; Nielsen, Norman; Matthews, Manyalibo J.

    2015-10-01

    We describe a model for far-field scattered power and irradiance by a silica glass slab with a shallow-pitted exit surface and is experimentally validated. The comparison to the model is performed using a precisely micromachined ensemble of ~11 μm wide laser ablated shallow pits producing 1% of the incident beam scatter in a 10 mrad angle. This series of samples with damage initiations and laser-induced shallow pits resulting from 351 nm, 5 ns pulsed laser cleaning of metal microparticles at different fluences between 2 J/cm2 and 11 J/cm2 are characterized as well and found in good agreement with model predictions.

  12. Measurement of optical scattered power from laser-induced shallow pits on silica

    SciTech Connect (OSTI)

    Feigenbaum, Eyal; Nielsen, Norman; Matthews, Manyalibo J.

    2015-10-01

    We describe a model for far-field scattered power and irradiance by a silica glass slab with a shallow-pitted exit surface and is experimentally validated. The comparison to the model is performed using a precisely micromachined ensemble of ~11 μm wide laser ablated shallow pits producing 1% of the incident beam scatter in a 10 mrad angle. This series of samples with damage initiations and laser-induced shallow pits resulting from 351 nm, 5 ns pulsed laser cleaning of metal microparticles at different fluences between 2 J/cm2 and 11 J/cm2 are characterized as well and found in good agreement with model predictions.

  13. Light scattering from laser induced pit ensembles on high power laser optics

    SciTech Connect (OSTI)

    Feigenbaum, Eyal [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Elhadj, Selim [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Matthews, Manyalibo J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-01-01

    Far-field light scattering characteristics from randomly arranged shallow Gaussian-like shaped laser induced pits, found on optics exposed to high energy laser pulses, is studied. Closed-form expressions for the far-field intensity distribution and scattered power are derived for individual pits and validated using numerical calculations of both Fourier optics and FDTD solutions to Maxwells equations. It is found that the scattered power is proportional to the square of the pit width and approximately also to the square of the pit depth, with the proportionality factor scaling with pit depth. As a result, the power scattered from shallow pitted optics is expected to be substantially lower than assuming complete scattering from the total visible footprint of the pits.

  14. Spark gap with low breakdown voltage jitter

    DOE Patents [OSTI]

    Rohwein, Gerald J.; Roose, Lars D.

    1996-01-01

    Novel spark gap devices and electrodes are disclosed. The novel spark gap devices and electrodes are suitable for use in a variety of spark gap device applications. The shape of the electrodes gives rise to local field enhancements and reduces breakdown voltage jitter. Breakdown voltage jitter of approximately 5% has been measured in spark gaps according the invention. Novel electrode geometries and materials are disclosed.

  15. Spark gap with low breakdown voltage jitter

    DOE Patents [OSTI]

    Rohwein, G.J.; Roose, L.D.

    1996-04-23

    Novel spark gap devices and electrodes are disclosed. The novel spark gap devices and electrodes are suitable for use in a variety of spark gap device applications. The shape of the electrodes gives rise to local field enhancements and reduces breakdown voltage jitter. Breakdown voltage jitter of approximately 5% has been measured in spark gaps according the invention. Novel electrode geometries and materials are disclosed. 13 figs.

  16. Surface breakdown igniter for mercury arc devices

    DOE Patents [OSTI]

    Bayless, John R.

    1977-01-01

    Surface breakdown igniter comprises a semiconductor of medium resistivity which has the arc device cathode as one electrode and has an igniter anode electrode so that when voltage is applied between the electrodes a spark is generated when electrical breakdown occurs over the surface of the semiconductor. The geometry of the igniter anode and cathode electrodes causes the igniter discharge to be forced away from the semiconductor surface.

  17. Humidity effects on wire insulation breakdown strength.

    SciTech Connect (OSTI)

    Appelhans, Leah

    2013-08-01

    Methods for the testing of the dielectric breakdown strength of insulation on metal wires under variable humidity conditions were developed. Two methods, an ASTM method and the twisted pair method, were compared to determine if the twisted pair method could be used for determination of breakdown strength under variable humidity conditions. It was concluded that, although there were small differences in outcomes between the two testing methods, the non-standard method (twisted pair) would be appropriate to use for further testing of the effects of humidity on breakdown performance. The dielectric breakdown strength of 34G copper wire insulated with double layer Poly-Thermaleze/Polyamide-imide insulation was measured using the twisted pair method under a variety of relative humidity (RH) conditions and exposure times. Humidity at 50% RH and below was not found to affect the dielectric breakdown strength. At 80% RH the dielectric breakdown strength was significantly diminished. No effect for exposure time up to 140 hours was observed at 50 or 80%RH.

  18. Measurement and Control of Glass Feedstocks

    SciTech Connect (OSTI)

    2005-08-01

    Laser-induced breakdown spectroscopy (LIBS) promises a new way for glass manufacturers to significantly increase productivity. By measuring the chemical makeup in raw materials and recycled glass cullet, LIBS can quickly detect contaminants and batch non...

  19. Monitoring and Control of Alkali Volatilization and Batch Carryover for Minimization of Particulates and Crown Corrosion

    SciTech Connect (OSTI)

    2001-01-01

    New Technology will Allow Glass Manufacturers to Optimize Furnace Conditions. Laser-induced breakdown spectroscopy is a continuous monitoring technique that glass manufacturers can use to reduce particulate matter emissions and extend furnace life.

  20. Four Los Alamos projects selected as R&D 100 Award finalists

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Finalists include X-ray imaging, pipe corrosion, data handling and damage-detection ... PipeLIBS (Laser-Induced Breakdown Spectroscopy) is an elemental-analysis system that uses ...

  1. Formation of laser-induced periodic surface structures on niobium by femtosecond laser irradiation

    SciTech Connect (OSTI)

    Pan, A.; Dias, A.; Gomez-Aranzadi, M.; Olaizola, S. M.; Rodriguez, A.

    2014-05-07

    The surface morphology of a Niobium sample, irradiated in air by a femtosecond laser with a wavelength of 800 nm and pulse duration of 100 fs, was examined. The period of the micro/nanostructures, parallel and perpendicularly oriented to the linearly polarized fs-laser beam, was studied by means of 2D Fast Fourier Transform analysis. The observed Laser-Induced Periodic Surface Structures (LIPSS) were classified as Low Spatial Frequency LIPSS (periods about 600 nm) and High Spatial Frequency LIPSS, showing a periodicity around 300 nm, both of them perpendicularly oriented to the polarization of the incident laser wave. Moreover, parallel high spatial frequency LIPSS were observed with periods around 100 nm located at the peripheral areas of the laser fingerprint and overwritten on the perpendicular periodic gratings. The results indicate that this method of micro/nanostructuring allows controlling the Niobium grating period by the number of pulses applied, so the scan speed and not the fluence is the key parameter of control. A discussion on the mechanism of the surface topology evolution was also introduced.

  2. Femtosecond laser-induced periodic surface structure on the Ti-based nanolayered thin films

    SciTech Connect (OSTI)

    Petrovi?, Suzana M.; Gakovi?, B.; Peruko, D.; Stratakis, E.; Department of Materials Science and Technology, University of Crete, 710 03 Heraklion, Crete ; Bogdanovi?-Radovi?, I.; ?ekada, M.; Fotakis, C.; Department of Physics, University of Crete, 714 09 Heraklion, Crete ; Jelenkovi?, B.

    2013-12-21

    Laser-induced periodic surface structures (LIPSSs) and chemical composition changes of Ti-based nanolayered thin films (Al/Ti, Ni/Ti) after femtosecond (fs) laser pulses action were studied. Irradiation is performed using linearly polarized Ti:Sapphire fs laser pulses of 40 fs pulse duration and 800 nm wavelength. The low spatial frequency LIPSS (LSFL), oriented perpendicular to the laser polarization with periods slightly lower than the irradiation wavelength, was typically formed at elevated laser fluences. On the contrary, high spatial frequency LIPSS (HSFL) with uniform period of 155 nm, parallel to the laser light polarization, appeared at low laser fluences, as well as in the wings of the Gaussian laser beam distribution for higher used fluence. LSFL formation was associated with the material ablation process and accompanied by the intense formation of nanoparticles, especially in the Ni/Ti system. The composition changes at the surface of both multilayer systems in the LSFL area indicated the intermixing between layers and the substrate. Concentration and distribution of all constitutive elements in the irradiated area with formed HSFLs were almost unchanged.

  3. Influence of substrate microcrystallinity on the orientation of laser-induced periodic surface structures

    SciTech Connect (OSTI)

    Nürnberger, P.; Reinhardt, H.; Kim, H-C.; Yang, F.; Peppler, K.; Janek, J.; Hampp, N.

    2015-10-07

    The research in this paper deals with the angular dependence of the formation of laser-induced periodic surface structures (LIPSS) by linearly polarized nanosecond laser pulses on polycrystalline austenitic stainless steel. Incident angles ranging from 45° to 70° lead to the generation of superimposed merely perpendicular oriented LIPSS on steel as well as on monocrystalline (100) silicon which was used as a reference material. Additional extraordinary orientations of superimposing LIPSS along with significantly different periodicities are found on polycrystalline steel but not on (100) silicon. Electron backscatter diffraction measurements indicate that the expansion of these LIPSS is limited to the grain size and affected by the crystal orientation of the individual grains. Atomic force microscopy imaging shows that LIPSS fringe heights are in good agreement with the theoretically predicted penetration depths of surface plasmon polaritons into stainless steel. These results indicate that optical anisotropies must be taken into account to fully describe the theory of light-matter interaction leading to LIPSS formation.

  4. Laser-Induced Forward Transfer Using Triazene Polymer Dynamic Releaser Layer

    SciTech Connect (OSTI)

    Stewart, James Shaw; Lippert, Thomas; Wokaun, Alexander; Nagel, Matthias; Nueesch, Frank

    2010-10-08

    This article presents a short review of the use of triazene polymer as a dynamic release layer (DRL) for laser-induced forward transfer (LIFT), before looking at the latest research in more detail. The field of triazene polymer ablation only started around 20 years ago and has grown rapidly into a number of different application areas. Most promisingly, triazene ablation has been refined as a method for propulsion, bringing the benefits of LIFT to the deposition of sensitive transfer materials. The key to understanding LIFT with a triazene DRL is to understand the more fundamental nature of triazene polymer ablation in both frontside and backside orientations. This article focuses on the most recent experimental results on LIFT with a triazene DRL: the effect of picosecond pulse lengths compared with nanosecond pulse lengths; the effect of reduced air pressure; and the improvements in transfer in terms of range of transfer materials, and transfer across a gap. The results all help improve fundamental understanding of triazene-based LIFT, and the transfer of functioning OLEDs demonstrates the capability of the technique.

  5. Microwave pulse compression from a storage cavity with laser-induced switching

    DOE Patents [OSTI]

    Bolton, Paul R.

    1992-01-01

    A laser-induced switch and a multiple cavity configuration are disclosed for producing high power microwave pulses. The microwave pulses are well controlled in wavelength and timing, with a quick rise time and a variable shape and power of the pulse. In addition, a method of reducing pre-pulse leakage to a low level is disclosed. Microwave energy is directed coherently to one or more cavities that stores the energy in a single mode, represented as a standing wave pattern. In order to switch the stored microwave energy out of the main cavity and into the branch waveguide, a laser-actuated switch is provided for the cavity. The switch includes a laser, associated optics for delivering the beam into the main cavity, and a switching gas positioned at an antinode in the main cavity. When actuated, the switching gas ionizes, creating a plasma, which becomes reflective to the microwave energy, changing the resonance of the cavity, and as a result the stored microwave energy is abruptly switched out of the cavity. The laser may directly pre-ionize the switching gas, or it may pump an impurity in the switching gas to an energy level which switches when a pre-selected cavity field is attained. Timing of switching the cavities is controlled by varying the pathlength of the actuating laser beam. For example, the pathlengths may be adjusted to output a single pulse of high power, or a series of quick lower power pulses.

  6. Femtosecond laser induced periodic surface structures on multi-layer graphene

    SciTech Connect (OSTI)

    Beltaos, Angela Kova?evi?, Aleksander G.; Matkovi?, Aleksandar; Ralevi?, Uro; Savi?-evi?, Svetlana; Jovanovi?, Djordje; Jelenkovi?, Branislav M.; Gaji?, Rado

    2014-11-28

    In this work, we present an observation of laser induced periodic surface structures (LIPSS) on graphene. LIPSS on other materials have been observed for nearly 50 years, but until now, not on graphene. Our findings for LIPSS on multi-layer graphene were consistent with previous reports of LIPSS on other materials, thus classifying them as high spatial frequency LIPSS. LIPSS on multi-layer graphene were generated in an air environment by a linearly polarized femtosecond laser with excitation wavelength ? of 840?nm, pulse duration ? of ?150 fs, and a fluence F of ?4.34.4 mJ/cm{sup 2}. The observed LIPSS were perpendicular to the laser polarization and had dimensions of width w of ?3040?nm and length l of ?0.51.5??m, and spatial periods ? of ?70100?nm (??/8?/12), amongst the smallest of spatial periods reported for LIPSS on other materials. The spatial period and width of the LIPSS were shown to decrease for an increased number of laser shots. The experimental results support the leading theory behind high spatial frequency LIPSS formation, implying the involvement of surface plasmon polaritons. This work demonstrates a new way to pattern multi-layer graphene in a controllable manner, promising for a variety of emerging graphene/LIPSS applications.

  7. Experimental evidence of new tetragonal polymorphs of silicon formed through ultrafast laser-induced confined microexplosion

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Rapp, L.; Haberl, B.; Pickard, C. J.; Bradby, J. E.; Gamaly, E. G.; Williams, J. S.; Rode, A. V.

    2015-06-29

    Ordinary materials can transform into novel phases with new crystal structures at extraordinary high pressure and temperature applied under both equilibrium and non-equilibrium conditions 1-6. The recently developed method of ultra-short laser-induced confined microexplosions 7-9 extends the range of possible new phases by initiating a highly non-equilibrium plasma state deep inside a bulk material 7-12. Ultra-high quenching rates can help to overcome kinetic barriers to the formation of new metastable phases, while the surrounding pristine crystal confines the affected material and preserves it for further study 10-12. Here we demonstrate that ultra-rapid pressure release from a completely disordered plasma statemore » in silicon produces several new metastable end phases quenched to ambient conditions. Their structure is determined from comparison to an ab initio random structure search which revealed six new energetically competitive potential phases, four tetragonal and two monoclinic ones. We show the presence of bt8 and st12, which have been predicted theoretically previously 13-15, but have not been observed in nature or in laboratory experiments. Additionally, the presence of the as yet unidentified silicon phase, Si-VIII and two of our other predicted tetragonal phases are highly likely within laser-affected zones. These findings pave the way for new materials with novel and exotic properties.« less

  8. Revision of laser-induced damage threshold evaluation from damage probability data

    SciTech Connect (OSTI)

    Bataviciute, Gintare; Grigas, Povilas; Smalakys, Linas; Melninkaitis, Andrius

    2013-04-15

    In this study, the applicability of commonly used Damage Frequency Method (DFM) is addressed in the context of Laser-Induced Damage Threshold (LIDT) testing with pulsed lasers. A simplified computer model representing the statistical interaction between laser irradiation and randomly distributed damage precursors is applied for Monte Carlo experiments. The reproducibility of LIDT predicted from DFM is examined under both idealized and realistic laser irradiation conditions by performing numerical 1-on-1 tests. A widely accepted linear fitting resulted in systematic errors when estimating LIDT and its error bars. For the same purpose, a Bayesian approach was proposed. A novel concept of parametric regression based on varying kernel and maximum likelihood fitting technique is introduced and studied. Such approach exhibited clear advantages over conventional linear fitting and led to more reproducible LIDT evaluation. Furthermore, LIDT error bars are obtained as a natural outcome of parametric fitting which exhibit realistic values. The proposed technique has been validated on two conventionally polished fused silica samples (355 nm, 5.7 ns).

  9. Catastrophic nanosecond laser induced damage in the bulk of potassium titanyl phosphate crystals

    SciTech Connect (OSTI)

    Wagner, Frank R. Natoli, Jean-Yves; Akhouayri, Hassan; Commandré, Mireille; Duchateau, Guillaume

    2014-06-28

    Due to its high effective nonlinearity and the possibility to produce periodically poled crystals, potassium titanyl phosphate (KTiOPO{sub 4}, KTP) is still one of the economically important nonlinear optical materials. In this overview article, we present a large study on catastrophic nanosecond laser induced damage in this material and the very similar RbTiOPO{sub 4} (RTP). Several different systematic studies are included: multiple pulse laser damage, multi-wavelength laser damage in KTP, damage resistance anisotropy, and variations of the laser damage thresholds for RTP crystals of different qualities. All measurements were carried out in comparable experimental conditions using a 1064 nm Q-switched laser and some were repeated at 532 nm. After summarizing the experimental results, we detail the proposed model for laser damage in this material and discuss the experimental results in this context. According to the model, nanosecond laser damage is caused by light-induced generation of transient laser-damage precursors which subsequently provide free electrons that are heated by the same nanosecond pulse. We also present a stimulated Raman scattering measurement and confront slightly different models to the experimental data. Finally, the physical nature of the transient damage precursors is discussed and similarities and differences to laser damage in other crystals are pointed out.

  10. Cost Codes and the Work Breakdown Structure

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    1997-03-28

    The chapter discusses the purpose of the work breakdown structure (WBS) and code of account (COA) cost code system, shows the purpose and fundamental structure of both the WBS and the cost code system, and explains the interface between the two systems.

  11. Heat generation above break-even from laser-induced fusion in ultra-dense deuterium

    SciTech Connect (OSTI)

    Holmlid, Leif

    2015-08-15

    Previous results from laser-induced processes in ultra-dense deuterium D(0) give conclusive evidence for ejection of neutral massive particles with energy >10 MeV u{sup −1}. Such particles can only be formed from nuclear processes like nuclear fusion at the low laser intensity used. Heat generation is of interest for future fusion energy applications and has now been measured by a small copper (Cu) cylinder surrounding the laser target. The temperature rise of the Cu cylinder is measured with an NTC resistor during around 5000 laser shots per measured point. No heating in the apparatus or the gas feed is normally used. The fusion process is suboptimal relative to previously published studies by a factor of around 10. The small neutral particles H{sub N}(0) of ultra-dense hydrogen (size of a few pm) escape with a substantial fraction of the energy. Heat loss to the D{sub 2} gas (at <1 mbar pressure) is measured and compensated for under various conditions. Heat release of a few W is observed, at up to 50% higher energy than the total laser input thus a gain of 1.5. This is uniquely high for the use of deuterium as fusion fuel. With a slightly different setup, a thermal gain of 2 is reached, thus clearly above break-even for all neutronicity values possible. Also including the large kinetic energy which is directly measured for MeV particles leaving through a small opening gives a gain of 2.3. Taking into account the lower efficiency now due to the suboptimal fusion process, previous studies indicate a gain of at least 20 during long periods.

  12. Radiation characteristics of femtosecond laser-induced plasma channel Vee antenna

    SciTech Connect (OSTI)

    Choe, Yun-Sik; Hao, Zuoqiang; Lin, Jingquan

    2015-06-15

    A virtual reconfigurable plasma Vee antenna consisting of a set of laser plasma filaments produced by femtosecond laser pulses in air is investigated in this paper. The calculation results show that radiation pattern becomes more complex and gain shows initially rapid rise but gradually saturate as the leg length increases, but the pattern and gain are not seriously affected by the plasma conductivity; particularly, the gain of the Vee antenna with plasma conductivity σ = 100S/m can reach about 80% of that of a copper antenna. Radiation efficiency of the antenna has shown a strong dependence on radius of the antenna leg, and an efficiency of 65%, considered to have a proper performance, can be obtained with the channel radius of about 10 mm. Apex angle variation can lead to significant change of the radiation pattern and influence the gain; the best apex angle corresponding to maximal gain and good directivity for the third resonance antenna leg length is found to be at 74° at 600 MHz and σ = 100 S/m. The calculation has shown that at terawatt laser power level, the plasma channel conductivity is close to that of conventional plasma antenna, and peak gain of the Vee antenna is more than 8 dB with a good directivity. In addition, the radiation pattern of special Vee antennas with apex angle 180°-dipole antennas, for first and third resonance leg lengths, is compared and underneath physics of the difference is given. The laser-induced plasma channel antenna is especially suitable for achieving good directivity and gain, which has advantage over conventional plasma antenna with gas discharge tube or metal antenna.

  13. Model-independent determination of the astrophysical S factor in laser-induced fusion plasmas

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lattuada, D.; Barbarino, M.; Bonasera, A.; Bang, W.; Quevedo, H. J.; Warren, M.; Consoli, F.; De Angelis, R.; Andreoli, P.; Kimura, S.; et al

    2016-04-01

    In this paper, we present a new and general method for measuring the astrophysical S factor of nuclear reactions in laser-induced plasmas and we apply it to 2H(d,n)3He. The experiment was performed with the Texas Petawatt Laser, which delivered 150–270 fs pulses of energy ranging from 90 to 180 J to D2 or CD4 molecular clusters (where D denotes 2H). After removing the background noise, we used the measured time-of-flight data of energetic deuterium ions to obtain their energy distribution. We derive the S factor using the measured energy distribution of the ions, the measured volume of the fusion plasma,more » and the measured fusion yields. This method is model independent in the sense that no assumption on the state of the system is required, but it requires an accurate measurement of the ion energy distribution, especially at high energies, and of the relevant fusion yields. In the 2H(d,n)3He and 3He(d,p)4He cases discussed here, it is very important to apply the background subtraction for the energetic ions and to measure the fusion yields with high precision. While the available data on both ion distribution and fusion yields allow us to determine with good precision the S factor in the d+d case (lower Gamow energies), for the d+3He case the data are not precise enough to obtain the S factor using this method. Our results agree with other experiments within the experimental error, even though smaller values of the S factor were obtained. This might be due to the plasma environment differing from the beam target conditions in a conventional accelerator experiment.« less

  14. Ambient methods and apparatus for rapid laser trace constituent analysis

    DOE Patents [OSTI]

    Snyder, Stuart C.; Partin, Judy K.; Grandy, Jon D.; Jeffery, Charles L.

    2002-01-01

    A method and apparatus are disclosed for measuring trace amounts of constituents in samples by using laser induced breakdown spectroscopy and laser induced fluorescence under ambient conditions. The laser induced fluorescence is performed at a selected wavelength corresponding to an absorption state of a selected trace constituent. The intensity value of the emission decay signal which is generated by the trace constituent is compared to calibrated emission intensity decay values to determine the amount of trace constituent present.

  15. Prevention of breakdown behind railgun projectiles

    DOE Patents [OSTI]

    Hawke, R.S.

    1992-09-01

    An electromagnetic railgun accelerator system, for accelerating projectiles by a plasma arc, introduces a breakdown inhibiting gas into the railgun chamber behind the accelerating projectile. The breakdown inhibiting gas, which absorbs electrons, is a halide or a halide compound such as fluorine or SF[sub 6]. The gas is introduced between the railgun rails after the projectile has passed through inlets in the rails or the projectile; by coating the rails or the projectile with a material which releases the gas after the projectile passes over it; by fabricating the rails or the projectile or insulators out of a material which releases the gas into the portions of the chamber through which the projectile has travelled. The projectile may have a cavity at its rear to control the release of ablation products. 12 figs.

  16. Prevention of breakdown behind railgun projectiles

    DOE Patents [OSTI]

    Hawke, R.S.

    1992-10-13

    An electromagnetic railgun accelerator system, for accelerating projectiles by a plasma arc, introduces a breakdown inhibiting gas into the railgun chamber behind the accelerating projectile. The breakdown inhibiting gas, which absorbs electrons, is a halide or a halide compound such as fluorine or SF[sub 6]. The gas is introduced between the railgun rails after the projectile has passed through inlets in the rails or the projectile; by coating the rails or the projectile with a material which releases the gas after the projectile passes over it; by fabricating the rails or the projectile or insulators out of a material which releases the gas into the portions of the chamber through which the projectile has travelled. The projectile may have a cavity at its rear to control the release of ablation products. 12 figs.

  17. Prevention of breakdown behind railgun projectiles

    DOE Patents [OSTI]

    Hawke, Ronald S. (Livermore, CA)

    1992-01-01

    An electromagnetic railgun accelerator system, for accelerating projectiles (14, 15, 114, 214, 314, 414) by a plasma arc (3), introduces a breakdown inhibiting gas into the railgun chamber (26) behind the accelerating projectile (14). The breakdown inhibiting gas, which absorbs electrons, is a halide or a halide compound such as fluorine or SF.sub.6. The gas is introduced between the railgun rails (12) after the projectile (14) has passed through inlets (16) in the rails (12) or the projectile (114); by coating the rails (12) or the projectile (15) with a material (28) which releases the gas after the projectile (14) passes over it; by fabricating the rails (12) or the projectile (15) or insulators out of a material which releases the gas into the portions of the chamber (26) through which the projectile has travelled. The projectile (214, 314, 414) may have a cavity (232, 332, 432) at its rear to control the release of ablation products (4).

  18. Prevention of breakdown behind railgun projectiles

    DOE Patents [OSTI]

    Hawke, Ronald S. (Livermore, CA)

    1992-01-01

    An electromagnetic railgun accelerator system, for accelerating projectiles (14, 15, 114, 214, 314, 444) by a plasma arc (3), introduces a breakdown inhibiting gas into the railgun chamber (26) behind the accelerating projectile (14). The breakdown inhibiting gas, which absorbs electrons, is a halide or a halide compound such as fluorine or SF.sub.6. The gas is introduced between the railgun rails (12) after the projectile (14) has passed through inlets (16) in the rails (12) or the projectile (114); by coating the rails (12) or the projectile (15) with a material (28) which releases the gas after the projectile (14 ) passes over it; by fabricating the rails (12) or the projectile (15) or insulators out of a material which releases the gas into the portions of the chamber (26) through which the projectile has travelled. The projectile (214, 314, 414) may have a cavity (232, 332, 432) at its rear to control the release of ablation products (4).

  19. SU-E-J-161: Inverse Problems for Optical Parameters in Laser Induced Thermal Therapy

    SciTech Connect (OSTI)

    Fahrenholtz, SJ; Stafford, RJ; Fuentes, DT

    2014-06-01

    Purpose: Magnetic resonance-guided laser-induced thermal therapy (MRgLITT) is investigated as a neurosurgical intervention for oncological applications throughout the body by active post market studies. Real-time MR temperature imaging is used to monitor ablative thermal delivery in the clinic. Additionally, brain MRgLITT could improve through effective planning for laser fiber's placement. Mathematical bioheat models have been extensively investigated but require reliable patient specific physical parameter data, e.g. optical parameters. This abstract applies an inverse problem algorithm to characterize optical parameter data obtained from previous MRgLITT interventions. Methods: The implemented inverse problem has three primary components: a parameter-space search algorithm, a physics model, and training data. First, the parameter-space search algorithm uses a gradient-based quasi-Newton method to optimize the effective optical attenuation coefficient, ?-eff. A parameter reduction reduces the amount of optical parameter-space the algorithm must search. Second, the physics model is a simplified bioheat model for homogeneous tissue where closed-form Green's functions represent the exact solution. Third, the training data was temperature imaging data from 23 MRgLITT oncological brain ablations (980 nm wavelength) from seven different patients. Results: To three significant figures, the descriptive statistics for ?-eff were 1470 m{sup ?1} mean, 1360 m{sup ?1} median, 369 m{sup ?1} standard deviation, 933 m{sup ?1} minimum and 2260 m{sup ?1} maximum. The standard deviation normalized by the mean was 25.0%. The inverse problem took <30 minutes to optimize all 23 datasets. Conclusion: As expected, the inferred average is biased by underlying physics model. However, the standard deviation normalized by the mean is smaller than literature values and indicates an increased precision in the characterization of the optical parameters needed to plan MRgLITT procedures. This

  20. Improved generation of ion fluxes by a long laser pulse using laser-induced cavity pressure acceleration

    SciTech Connect (OSTI)

    Badziak, J.; Parys, P.; Rosi?ski, M.; Krousky, E.; Ullschmied, J.; Torrisi, L.; Dipartimento di Fisica, Universita di Messina, 98166 S. Agata, Messina

    2013-09-16

    Generation of ion fluxes in the laser-induced cavity pressure acceleration (LICPA) scheme is investigated by the time-of-flight method and compared with the one in the conventional laser-planar target interaction scheme. It is shown that the ion current density and intensity of the ion flux produced in the LICPA scheme from CD{sub 2} foil target irradiated by a 0.3-ns laser pulse of intensity ?10{sup 14}10{sup 15} W/cm{sup 2} are by an order of magnitude higher and the mean and maximum ion energies by a factor 45 higher than those for the conventional scheme.

  1. High-speed laser-induced fluorescence and spark plug absorption sensor diagnostics for mixing and combustion studies in engines

    SciTech Connect (OSTI)

    Cundy, Michael; Schucht, Torsten; Thiele, Olaf; Sick, Volker

    2009-02-01

    Simultaneous high-speed in-cylinder measurements of laser-induced fluorescence of biacetyl as a fuel tracer and mid-infrared broadband absorption of fuel and combustion products (water and carbon dioxide) using a spark plug probe are compared in an optical engine. The study addresses uncertainties and the applicability of absorption measurements at a location slightly offset to the spark plug when information about mixing at the spark plug is desired. Absorbance profiles reflect important engine operation events, such as valve opening and closing, mixing, combustion, and outgassing from crevices.

  2. Influence of crystal orientation on the formation of femtosecond laser-induced periodic surface structures and lattice defects accumulation

    SciTech Connect (OSTI)

    Sedao, Xxx; Garrelie, Florence Colombier, Jean-Philippe; Reynaud, Stéphanie; Pigeon, Florent; Maurice, Claire; Quey, Romain

    2014-04-28

    The influence of crystal orientation on the formation of femtosecond laser-induced periodic surface structures (LIPSS) has been investigated on a polycrystalline nickel sample. Electron Backscatter Diffraction characterization has been exploited to provide structural information within the laser spot on irradiated samples to determine the dependence of LIPSS formation and lattice defects (stacking faults, twins, dislocations) upon the crystal orientation. Significant differences are observed at low-to-medium number of laser pulses, outstandingly for (111)-oriented surface which favors lattice defects formation rather than LIPSS formation.

  3. Ultraviolet laser-induced poling inhibition produces bulk domains in MgO-doped lithium niobate crystals

    SciTech Connect (OSTI)

    Boes, Andreas, E-mail: s3363819@student.rmit.edu.au; Steigerwald, Hendrik; Sivan, Vijay; Mitchell, Arnan [School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria 3001 (Australia); ARC Center for Ultra-high Bandwidth Devices for Optical Systems (CUDOS), RMIT University, Melbourne, Victoria 3001 (Australia); Yudistira, Didit [School of Electrical and Computer Engineering, RMIT University, Melbourne, Victoria 3001 (Australia); Wade, Scott [Faculty of Science, Engineering and Technology, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia); Mailis, Sakellaris [Optoelectronics Research Centre, University of Southampton, Highfield, Southampton SO17 1BJ (United Kingdom); Soergel, Elisabeth [Institute of Physics, University of Bonn, Wegelerstr. 8, 53115 Bonn (Germany)

    2014-09-01

    We report the realization of high-resolution bulk domains achieved using a shallow, structured, domain inverted surface template obtained by UV laser-induced poling inhibition in MgO-doped lithium niobate. The quality of the obtained bulk domains is compared to those of the template and their application for second harmonic generation is demonstrated. The present method enables domain structures with a period length as small as 3??m to be achieved. Furthermore, we propose a potential physical mechanism that leads to the transformation of the surface template into bulk domains.

  4. Effect of defects on long-pulse laser-induced damage of two kinds of optical thin films

    SciTech Connect (OSTI)

    Wang Bin; Qin Yuan; Ni Xiaowu; Shen Zhonghua; Lu Jian

    2010-10-10

    In order to study the effect of defects on the laser-induced damage of different optical thin films, we carried out damage experiments on two kinds of thin films with a 1ms long-pulse laser. Surface-defect and subsurface-defect damage models were used to explain the damage morphology. The two-dimensional finite element method was applied to calculate the temperature and thermal-stress fields of these two films. The results show that damages of the two films are due to surface and subsurface defects, respectively. Furthermore, the different dominant defects for thin films of different structures are discussed.

  5. RF BREAKDOWN STUDIES USING PRESSURIZED CAVITIES

    SciTech Connect (OSTI)

    Johnson, Rolland

    2014-09-21

    Many present and future particle accelerators are limited by the maximum electric gradient and peak surface fields that can be realized in RF cavities. Despite considerable effort, a comprehensive theory of RF breakdown has not been achieved and mitigation techniques to improve practical maximum accelerating gradients have had only limited success. Part of the problem is that RF breakdown in an evacuated cavity involves a complex mixture of effects, which include the geometry, metallurgy, and surface preparation of the accelerating structures and the make-up and pressure of the residual gas in which plasmas form. Studies showed that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas, as needed for muon cooling channels, without the need for long conditioning times, even in the presence of strong external magnetic fields. This positive result was expected because the dense gas can practically eliminate dark currents and multipacting. In this project we used this high pressure technique to suppress effects of residual vacuum and geometry that are found in evacuated cavities in order to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. One of the interesting and useful outcomes of this project was the unanticipated collaborations with LANL and Fermilab that led to new insights as to the operation of evacuated normal-conducting RF cavities in high external magnetic fields. Other accomplishments included: (1) RF breakdown experiments to test the effects of SF6 dopant in H2 and He gases with Sn, Al, and Cu electrodes were carried out in an 805 MHz cavity and compared to calculations and computer simulations. The heavy corrosion caused by the SF6 components led to the suggestion that a small admixture of oxygen, instead of SF6, to the hydrogen would allow the same advantages without the corrosion in a practical muon beam line. (2) A

  6. COST BREAKDOWN AWARD NO: START DATE: EXPIRATION DATE: FISCAL YEAR BREAKDOWN OF FUNDS

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    COST BREAKDOWN AWARD NO: START DATE: EXPIRATION DATE: FISCAL YEAR BREAKDOWN OF FUNDS ELEMENTS FY FY FY FY FY TOTAL Direct Labor Overhead Materials Supplies Travel Other Direct Costs Subcontractors Total Direct Costs G&A Expense Total All Costs DOE Share* Awardee Share* Overhead Rate G&A Rate 1. The cost elements indicated are provided as an example only. Your firm should indicate the costs elements you have used on your invoices. 2. You should indicate the cost incurred for each of your

  7. Thickness effect on laser-induced-damage threshold of indium-tin oxide films at 1064 nm

    SciTech Connect (OSTI)

    Wang Haifeng; Huang Zhimeng; Zhang Dayong; Luo Fei; Huang Lixian; Li Yanglong; Luo Yongquan; Wang Weiping; Zhao Xiangjie

    2011-12-01

    Laser-induced-damage characteristics of commercial indium-tin oxide (ITO) films deposited by DC magnetron sputtering deposition on K9 glass substrates as a function of the film thickness have been studied at 1064 nm with a 10 ns laser pulse in the 1-on-1 mode, and the various mechanisms for thickness effect on laser-induced-damage threshold (LIDT) of the film have been discussed in detail. It is observed that laser-damage-resistance of ITO film shows dramatic thickness effect with the LIDT of the 50-nm ITO film 7.6 times as large as the value of 300 nm film, and the effect of depressed carrier density by decreasing the film thickness is demonstrated to be the primary reason. Our experiment findings indicate that searching transparent conductive oxide (TCO) film with low carrier density and high carrier mobility is an efficient technique to improve the laser-damage-resistance of TCO films based on maintaining their well electric conductivity.

  8. Quantum Oscillations from Nodal Bilayer Magnetic Breakdown in...

    Office of Scientific and Technical Information (OSTI)

    Title: Quantum Oscillations from Nodal Bilayer Magnetic Breakdown in the Underdoped High Temperature Superconductor YBa2Cu3O6+x Authors: Sebastian, Suchitra E. ; Harrison, N. ; ...

  9. Pre-breakdown evaluation of gas discharge mechanisms in microgaps

    SciTech Connect (OSTI)

    Semnani, Abbas; Peroulis, Dimitrios; Venkattraman, Ayyaswamy; Alexeenko, Alina A.

    2013-04-29

    The individual contributions of various gas discharge mechanisms to total pre-breakdown current in microgaps are quantified numerically. The variation of contributions of field emission and secondary electron emission with increasing electric field shows contrasting behavior even for a given gap size. The total current near breakdown decreases rapidly with gap size indicating that microscale discharges operate in a high-current, low-voltage regime. This study provides the first such analysis of breakdown mechanisms and aids in the formulation of physics-based theories for microscale breakdown.

  10. Using shaped pulses to probe energy deposition during laser-induced damage of SiO2 surfaces

    SciTech Connect (OSTI)

    Carr, C W; Cross, D; Feit, M D; Bude, J D

    2008-10-24

    Laser-induced damage initiation in silica has been shown to follow a power-law behavior with respect to pulse-length. Models based on thermal diffusion physics can successfully predict this scaling and the effect of pulse shape for pulses between about 3ns and 10ns. In this work we use sophisticated new measurement techniques and novel pulse shape experiments to test the limits of this scaling. We show that simple pulse length scaling fails for pulses below about 3ns. Furthermore, double pulse initiation experiments suggest that energy absorbed by the first pulse is lost on time scales much shorter than would be predicted for thermal diffusion. This time scale for energy loss can be strongly modulated by maintaining a small but non-zero intensity between the pulses. By producing damage with various pulse shapes and pulse trains it is demonstrated that the properties of any hypothetical thermal absorber become highly constrained.

  11. Enhancement of a laminar premixed methane/oxygen/nitrogen flame speed using femtosecond-laser-induced plasma

    SciTech Connect (OSTI)

    Yu Xin; Peng Jiangbo; Yi Yachao; Zhao Yongpeng; Chen Deying; Yu Junhua [National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin 150080 (China); Institute of Opto-electronics, Harbin Institute of Technology, Harbin 150080 (China); Yang Peng; Sun Rui [Institute of Combustion Engineering, Harbin Institute of Technology, Harbin 150001 (China)

    2010-07-05

    We first investigate the effects of femtosecond-laser-induced plasma on the flame speed of a laminar premixed methane/oxygen/nitrogen flame with a wide range of the equivalence ratios (0.8-1.05) at atmospheric pressure. It is experimentally found that the flame speed increases 20.5% at equivalence ratios 1.05. The self-emission spectra from the flame and the plasma are studied and an efficient production of active radicals under the action of femtosecond (fs)-laser pulses has been observed. Based on the experimental data obtained, the presence of oxygen atom and hydrocarbon radicals is suggested to be a key factor enhancing flame speed.

  12. Purification of Nanoscale Electron-Beam-Induced Platinum Deposits via a Pulsed Laser-Induced Oxidation Reaction

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Stanford, Michael G.; Lewis, Brett B.; Noh, Joo Hyon; Fowlkes, Jason Davidson; Roberts, Nicholas A.; Plank, Harald; Rack, Philip D.

    2014-11-05

    Platinum–carbon deposits made via electron-beam-induced deposition were purified in this study via a pulsed laser-induced oxidation reaction and erosion of the amorphous carbon to form pure platinum. Purification proceeds from the top down and is likely catalytically facilitated via the evolving platinum layer. Thermal simulations suggest a temperature threshold of ~485 K, and the purification rate is a function of the PtC5 thickness (80–360 nm) and laser pulse width (1–100 μs) in the ranges studied. The thickness dependence is attributed to the ~235 nm penetration depth of the PtC5 composite at the laser wavelength, and the pulse-width dependence is attributedmore » to the increased temperatures achieved at longer pulse widths. Finally, remarkably fast purification is realized at cumulative laser exposure times of less than 1 s.« less

  13. BH{sub 2} revisited: New, extensive measurements of laser-induced fluorescence transitions and ab initio calculations of near-spectroscopic accuracy

    SciTech Connect (OSTI)

    Sunahori, Fumie X.; Gharaibeh, Mohammed; Clouthier, Dennis J.; Tarroni, Riccardo

    2015-05-07

    The spectroscopy of gas phase BH{sub 2} has not been explored experimentally since the pioneering study of Herzberg and Johns in 1967. In the present work, laser-induced fluorescence (LIF) spectra of the A{sup ~} {sup 2}B{sub 1}(Π{sub u})−X{sup ~2}A{sub 1} band system of {sup 11}BH{sub 2}, {sup 10}BH{sub 2}, {sup 11}BD{sub 2}, and {sup 10}BD{sub 2} have been observed for the first time. The free radicals were “synthesized” by an electric discharge through a precursor mixture of 0.5% diborane (B{sub 2}H{sub 6} or B{sub 2}D{sub 6}) in high pressure argon at the exit of a pulsed valve. A total of 67 LIF bands have been measured and rotationally analyzed, 62 of them previously unobserved. These include transitions to a wide variety of excited state bending levels, to several stretch-bend combination levels, and to three ground state levels which gain intensity through Renner-Teller coupling to nearby excited state levels. As an aid to vibronic assignment of the spectra, very high level hybrid ab initio potential energy surfaces were built starting from the coupled cluster singles and doubles with perturbative triples (CCSD(T))/aug-cc-pV5Z level of theory for this seven-electron system. In an effort to obtain the highest possible accuracy, the potentials were corrected for core correlation, extrapolation to the complete basis set limit, electron correlation beyond CCSD(T), and diagonal Born-Oppenheimer effects. The spin-rovibronic states of the various isotopologues of BH{sub 2} were calculated for energies up to 22 000 cm{sup −1} above the X{sup ~} (000) level without any empirical adjustment of the potentials or fitting to experimental data. The agreement with the new LIF data is excellent, approaching near-spectroscopic accuracy (a few cm{sup −1}) and has allowed us to understand the complicated spin-rovibronic energy level structure even in the region of strong Renner-Teller resonances.

  14. X ray photoelectron analysis of oxide-semiconductor interface after breakdown in Al{sub 2}O{sub 3}/InGaAs stacks

    SciTech Connect (OSTI)

    Shekhter, P.; Palumbo, F.; Cohen Weinfeld, K.; Eizenberg, M.

    2014-09-08

    In this work, the post-breakdown characteristics of metal gate/Al{sub 2}O{sub 3}/InGaAs structures were studied using surface analysis by x ray photoelectron spectroscopy. The results show that for dielectric breakdown under positive bias, localized filaments consisting of oxidized substrate atoms (In, Ga and As) were formed, while following breakdown under negative bias, a decrease of oxidized substrate atoms was observed. Such differences in the microstructure at the oxide-semiconductor interface after breakdown for positive and negative voltages are explained by atomic diffusion of the contact atoms into the gate dielectric in the region of the breakdown spot by the current induced electro-migration effect. These findings show a major difference between Al{sub 2}O{sub 3}/InGaAs and SiO{sub 2}/Si interfaces, opening the way to a better understanding of the breakdown characteristics of III-V complementary-metal-oxide-semiconductor technology.

  15. Spectroscopy and reactions of vibrationally excited transient molecules

    SciTech Connect (OSTI)

    Dai, H.L.

    1993-12-01

    Spectroscopy, energy transfer and reactions of vibrationally excited transient molecules are studied through a combination of laser-based excitation techniques and efficient detection of emission from the energized molecules with frequency and time resolution. Specifically, a Time-resolved Fourier Transform Emission Spectroscopy technique has been developed for detecting dispersed laser-induced fluorescence in the IR, visible and UV regions. The structure and spectroscopy of the excited vibrational levels in the electronic ground state, as well as energy relaxation and reactions induced by specific vibronic excitations of a transient molecule can be characterized from time-resolved dispersed fluorescence in the visible and UV region. IR emissions from highly vibrational excited levels, on the other hand, reveal the pathways and rates of collision induced vibrational energy transfer.

  16. Laser induced effects on ZnO targets upon ablation at 266 and 308 nm wavelengths

    SciTech Connect (OSTI)

    Jadraque, Maria; Martin, Margarita; Domingo, Concepcion

    2008-07-15

    The development of structural changes in ZnO targets, upon laser irradiation at the wavelengths of 266 and 308 nm, is studied by Raman spectroscopy. At the wavelength of 308 nm, oxygen vacancies are found to develop monotonically with increasing laser intensity. At 266 nm, a structural change in the irradiated ZnO targets, possibly related to nanostructuring, is observed above the laser fluence of 0.45 J cm{sup -2}. The different natures of the laser target interaction processes taking place at both wavelengths are investigated through the characterization of the composition and energy distribution of the species ejected in the ablation. The energy of the neutral Zn and Zn{sub 2} present in the ablation at 308 nm shows a smooth dependence on laser fluence which is consistent with the observed smooth development of oxygen vacancies. At 266 nm, the average kinetic energy of the ejected fragments is higher than at 308 nm and changes abruptly with the ablating laser fluence, consistently with the presence of a fluence threshold above which structural transform is observed at this wavelength. The plume shows the same neutral composition (Zn, ZnO, and Zn{sub 2}) at both wavelengths but the dependence on fluence of the ratio of neutral atomic Zn to the dimer Zn{sub 2} shows significant differences. From the latter, different temperature regimes can be inferred in the plume generated at both wavelengths. At 266 nm the cationic composition of the plume is mainly stoichiometric whereas at 308 nm ZnO{sub 2(3)}H{sub 2(1)}{sup +} cations have the highest intensity.

  17. Vortex breakdown in closed containers with polygonal cross sections

    SciTech Connect (OSTI)

    Naumov, I. V. Dvoynishnikov, S. V.; Kabardin, I. K.; Tsoy, M. A.

    2015-12-15

    The vortex breakdown bubble in the confined flow generated by a rotating lid in closed containers with polygonal cross sections was analysed both experimentally and numerically for the height/radius aspect ratio equal to 2. The stagnation point locations of the breakdown bubble emergence and the corresponding Reynolds number were determined experimentally and in addition computed numerically by STAR-CCM+ CFD software for square, pentagonal, hexagonal, and octagonal cross section configurations. The flow pattern and the velocity were observed and measured by combining the seeding particle visualization and the temporal accuracy of laser Doppler anemometry. The vortex breakdown size and position on the container axis were determined for Reynolds numbers, ranging from 1450 to 2400. The obtained results were compared with the flow structure in the closed container of cubical and cylindrical configurations. It is shown that the measured evolution of steady vortex breakdown is in close agreement with the numerical results.

  18. MHK Cost Breakdown Structure Draft | OpenEI Community

    Open Energy Info (EERE)

    MHK Cost Breakdown Structure Draft Home > Groups > Water Power Forum Kch's picture Submitted by Kch(24) Member 15 July, 2014 - 07:07 CBS current energy GMREC LCOE levelized cost of...

  19. Temperature activated absorption during laser-induced damage: The evolution of laser-supported solid-state absorption fronts

    SciTech Connect (OSTI)

    Carr, C W; Bude, J D; Shen, N; Demange, P

    2010-10-26

    Previously we have shown that the size of laser induced damage sites in both KDP and SiO{sub 2} is largely governed by the duration of the laser pulse which creates them. Here we present a model based on experiment and simulation that accounts for this behavior. Specifically, we show that solid-state laser-supported absorption fronts are generated during a damage event and that these fronts propagate at constant velocities for laser intensities up to 4 GW/cm{sup 2}. It is the constant absorption front velocity that leads to the dependence of laser damage site size on pulse duration. We show that these absorption fronts are driven principally by the temperature-activated deep sub band-gap optical absorptivity, free electron transport, and thermal diffusion in defect-free silica for temperatures up to 15,000K and pressures < 15GPa. In addition to the practical application of selecting an optimal laser for pre-initiation of large aperture optics, this work serves as a platform for understanding general laser-matter interactions in dielectrics under a variety of conditions.

  20. Calculation of laser induced impulse based on the laser supported detonation wave model with dissociation, ionization and radiation

    SciTech Connect (OSTI)

    Gan, Li Mousen, Cheng; Xiaokang, Li

    2014-03-15

    In the laser intensity range that the laser supported detonation (LSD) wave can be maintained, dissociation, ionization and radiation take a substantial part of the incidence laser energy. There is little treatment on the phenomenon in the existing models, which brings obvious discrepancies between their predictions and the experiment results. Taking into account the impact of dissociation, ionization and radiation in the conservations of mass, momentum and energy, a modified LSD wave model is developed which fits the experimental data more effectively rather than the existing models. Taking into consideration the pressure decay of the normal and the radial rarefaction, the laser induced impulse that is delivered to the target surface is calculated in the air; and the dependencies of impulse performance on laser intensity, pulse width, ambient pressure and spot size are indicated. The results confirm that the dissociation is the pivotal factor of the appearance of the momentum coupling coefficient extremum. This study focuses on a more thorough understanding of LSD and the interaction between laser and matter.

  1. Pulsed laser-induced oxygen deficiency at TiO{sub 2} surface: Anomalous structure and electrical transport properties

    SciTech Connect (OSTI)

    Nakajima, Tomohiko; Tsuchiya, Tetsuo; Kumagai, Toshiya

    2009-09-15

    We have studied pulsed laser-induced oxygen deficiencies at rutile TiO{sub 2} surfaces. The crystal surface was successfully reduced by excimer laser irradiation, and an oxygen-deficient TiO{sub 2-{delta}} layer with 160 nm thickness was formed by means of ArF laser irradiation at 140 mJ/cm{sup 2} for 2000 pulses. The TiO{sub 2-{delta}} layer fundamentally maintained a rutile structure, though this structure was distorted by many stacking faults caused by the large oxygen deficiency. The electrical resistivity of the obtained TiO{sub 2-{delta}} layer exhibited unconventional metallic behavior with hysteresis. A metal-insulator transition occurred at 42 K, and the electrical resistivity exceeded 10{sup 4} OMEGA cm below 42 K. This metal-insulator transition could be caused by bipolaronic ordering derived from Ti-Ti pairings that formed along the stacking faults. The constant magnetization behavior observed below 42 K is consistent with the bipolaronic scenario that has been observed previously for Ti{sub 4}O{sub 7}. These peculiar electrical properties are strongly linked to the oxygen-deficient crystal structure, which contains many stacking faults formed by instantaneous heating during excimer laser irradiation. - Graphical abstract: A pulsed laser-irradiated TiO{sub 2-{delta}} substrate showed an unconventional metallic phase, with hysteresis over a wide range of temperatures and a metal-insulator transition at 42 K.

  2. A comparison of ion beam measurements by retarding field energy analyzer and laser induced fluorescence in helicon plasma devices

    SciTech Connect (OSTI)

    Gulbrandsen, N. Fredriksen, Å.; Carr, J.; Scime, E.

    2015-03-15

    Both Laser-Induced Fluorescence (LIF) and Retarding Field Energy Analyzers (RFEA) have been applied to the investigation of beams formed in inductively coupled helicon plasmas. While the LIF technique provides a direct measurement of the velocity distribution in the plasma, the RFEA measures ion flux as a function of a retarding potential. In this paper, we present a method to compare the two techniques, by converting the LIF velocity distribution to an equivalent of a RFEA measurement. We applied this method to compare new LIF and RFEA measurements in two different experiments; the Hot Helicon Experiment (HELIX) - Large Experiment on Instabilities and Anisotropies (LEIA) at West Virginia University and Njord at University of Tromsø. We find good agreement between beam energies of the two methods. In agreement with earlier observations, the RFEA is found to measure ion beams with densities too low for the LIF to resolve. In addition, we present measurements of the axial development of the ion beam in both experiments. Beam densities drop exponentially with distance from the source, both in LIF and RFEA measurements. The effective quenching cross section from LIF in LEIA is found to be σ{sub b,*}=4×10{sup −19} m{sup 2}, and the effective beam collisional cross sections by RFEA in Njord to be σ{sub b}=1.7×10{sup −18} m{sup 2}.

  3. Effects of aggregate morphology and size on laser-induced incandescence and scattering from black carbon (mature soot)

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bambha, Ray P.; Michelsen, Hope A.

    2015-07-03

    We have used a Single-Particle Soot Photometer (SP2) to measure time-resolved laser-induced incandescence (LII) and laser scatter from combustion-generated mature soot with a fractal dimension of 1.88 extracted from a burner. We have also made measurements on restructured mature-soot particles with a fractal dimension of 2.3–2.4. We reproduced the LII and laser-scatter temporal profiles with an energy- and mass-balance model, which accounted for heating of particles passed through a CW-laser beam over laser–particle interaction times of ~10 μs. Furthermore, the results demonstrate a strong influence of aggregate size and morphology on LII and scattering signals. Conductive cooling competes with absorptivemore » heating on these time scales; the effects are reduced with increasing aggregate size and fractal dimension. These effects can lead to a significant delay in the onset of the LII signal and may explain an apparent low bias in the SP2 measurements for small particle sizes, particularly for fresh, mature soot. The results also reveal significant perturbations to the measured scattering signal from LII interference and suggest rapid expansion of the aggregates during sublimation.« less

  4. Laser-induced temperature jump/time-resolved infrared study of the fast events in protein folding

    SciTech Connect (OSTI)

    Woodruff, W.H.; Dyer, R.B.; Williams, S. [Los Alamos National Laboratory, NM (United States); Callender, H.; Gilmanshin, R. [CUNY, NY (United States)

    1996-10-01

    Laser-induced temperature jump followed by time-resolved infrared probe of reaction dynamics are used to study the temporal evolution of polypeptide structure during protein folding and unfolding. Reactions are initiated in times of 50 ps or longer by T-jumps of 10`s of degrees, obtained by laser excitation of water overtone absorbances. Observation of the Amide I transient absorbances reveal melting lifetimes of helices unconstrained by tertiary structure to be ca. 160 ns in a model 21-peptide and ca. 30 ns in {open_quotes}molten globule{close_quotes} apomyoglobin. No other processes are observed in these systems over the timescale 50 ps to 2 ms. Equilibrium data suggest the corresponding helix formation lifetimes to be ca. 16 and 1 ns, respectively. In {open_quotes}native{close_quotes} apomyoglobin two helix melting lifetimes are observed and we infer that a third occurs on a timescale inaccessible to our experiment (> 1 ms). The shorter observed lifetime, as in the molten globule, is ca. 30 ns. The longer lifetime is ca. 70 {mu}s. We suggest that the slower process is helix melting that is rate-limited by the unfolding of tertiary structure. Equilibrium data suggest a lifetime of ca. 1 {mu}s for the development of these tertiary folds.

  5. Effects of repetitive pulsing on multi-kHz planar laser-induced incandescence imaging in laminar and turbulent flames

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Michael, James B.; Venkateswaran, Prabhakar; Shaddix, Christopher R.; Meyer, Terrence R.

    2015-04-08

    Planar laser-induced incandescence (LII) imaging is reported at repetition rates up to 100 kHz using a burst-mode laser system to enable studies of soot formation dynamics in highly turbulent flames. Furthermore, to quantify the accuracy and uncertainty of relative soot volume fraction measurements, the temporal evolution of the LII field in laminar and turbulent flames is examined at various laser operating conditions. Under high-speed repetitive probing, it is found that LII signals are sensitive to changes in soot physical characteristics when operating at high laser fluences within the soot vaporization regime. For these laser conditions, strong planar LII signals aremore » observed at measurement rates up to 100 kHz but are primarily useful for qualitative tracking of soot structure dynamics. However, LII signals collected at lower fluences allow sequential planar measurements of the relative soot volume fraction with a sufficient signal-to-noise ratio at repetition rates of 10–50 kHz. Finally, guidelines for identifying and avoiding the onset of repetitive probe effects in the LII signals are discussed, along with other potential sources of measurement error and uncertainty.« less

  6. AVLIS Production Plant work breakdown structure and Dictionary

    SciTech Connect (OSTI)

    Not Available

    1984-11-15

    The work breakdown structure has been prepared for the AVLIS Production Plant to define, organize, and identify the work efforts and is summarized in Fig. 1-1 for the top three project levels. The work breakdown structure itself is intended to be the primary organizational tool of the AVLIS Production Plant and is consistent with the overall AVLIS Program Work Breakdown Structure. It is designed to provide a framework for definition and accounting of all of the elements that are required for the eventual design, procurement, and construction of the AVLIS Production Plant. During the present phase of the AVLIS Project, the conceptual engineering phase, the work breakdown structure is intended to be the master structure and project organizer of documents, designs, and cost estimates. As the master project organizer, the key role of the work breakdown structure is to provide the mechanism for developing completeness in AVLIS cost estimates and design development of all hardware and systems. The work breakdown structure provides the framework for tracking, on a one-to-one basis, the component design criteria, systems requirements, design concepts, design drawings, performance projections, and conceptual cost estimates. It also serves as a vehicle for contract reporting. 12 figures, 2 tables.

  7. Laser induced rovibrational cooling of the linear polyatomic ion C{sub 2}H{sub 2}{sup +}

    SciTech Connect (OSTI)

    Deb, Nabanita; Heazlewood, Brianna R.; Rennick, Christopher J.; Softley, Timothy P.

    2014-04-28

    The laser-induced blackbody-assisted rotational cooling of a linear polyatomic ion, C{sub 2}H{sub 2}{sup +}, in its {sup 2}? ground electronic state in the presence of the blackbody radiation field at 300 K and 77 K is investigated theoretically using a rate-equations model. Although pure rotational transitions are forbidden in this non-polar species, the ?{sub 5} cis-bending mode is infrared active and the (1-0) band of this mode strongly overlaps the 300 K blackbody spectrum. Hence the lifetimes of state-selected rotational levels are found to be short compared to the typical timescale of ion trapping experiments. The ?{sub 5} (1-0) transition is split by the Renner-Teller coupling of vibrational and electronic angular momentum, and by the spin-orbit coupling, into six principal components and these effects are included in the calculations. In this paper, a rotational-cooling scheme is proposed that involves simultaneous pumping of a set of closely spaced Q-branch transitions on the {sup 2}?{sub 5/2} ? {sup 2}?{sub 3/2} band together with two Q-branch lines in the {sup 2}?{sup +} ? {sup 2}?{sub 1/2} band. It is shown that this should lead to >70% of total population in the lowest rotational level at 300 K and over 99% at 77 K. In principle, the multiple Q-branch lines could be pumped with just two broad-band (??? = 0.43 cm{sup ?1}) infrared lasers.

  8. Rapid Laser Induced Crystallization of Amorphous NiTi Films Observed by Nanosecond Dynamic Transmission Electron Microscopy (DTEM)

    SciTech Connect (OSTI)

    LaGrange, T; Campbell, G H; Browning, N D; Reed, B W; Grummon, D S

    2010-03-01

    The crystallization processes of the as-deposited, amorphous NiTi thin films have been studied in detail using techniques such as differential scanning calorimetry and, in-situ TEM. The kinetic data have been analyzed in terms of Johnson-Mehl-Avrami-Kolomogrov (JMAK) semi-empirical formula. The kinetic parameters determined from this analysis have been useful in defining process control parameters for tailoring microstructural features and shape memory properties. Due to the commercial push to shrink thin film-based devices, unique processing techniques have been developed using laser-based annealing to spatially control the microstructure evolution down to sub-micron levels. Nanosecond, pulse laser annealing is particularly attractive since it limits the amount of peripheral heating and unwanted microstructural changes to underlying or surrounding material. However, crystallization under pulsed laser irradiation can differ significantly from conventional thermal annealing, e.g., slow heating in a furnace. This is especially true for amorphous NiTi materials and relevant for shape memory thin film based microelectromechanical systems (MEMS) applications. There is little to no data on the crystallization kinetics of NiTi under pulsed laser irradiation, primarily due to the high crystallization rates intrinsic to high temperature annealing and the spatial and temporal resolution limits of standard techniques. However, with the high time and spatial resolution capabilities of the dynamic transmission electron microscope (DTEM) constructed at Lawrence Livermore National Laboratory, the rapid nucleation events occurring from pulsed laser irradiation can be directly observed and nucleation rates can be quantified. This paper briefly explains the DTEM approach and how it used to investigate the pulsed laser induced crystallization processes in NiTi and to determine kinetic parameters.

  9. Quantification of online removal of refractory black carbon using laser-induced incandescence in the single particle soot photometer

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Aiken, Allison C.; McMeeking, Gavin R.; Levin, Ezra J. T.; Dubey, Manvendra K.; DeMott, Paul J.; Kreidenweis, Sonia M.

    2016-04-05

    Refractory black carbon (rBC) is an aerosol that has important impacts on climate and human health. rBC is often mixed with other species, making it difficult to isolate and quantify its important effects on physical and optical properties of ambient aerosol. To solve this measurement challenge, a new method to remove rBC was developed using laser-induced incandescence (LII) by Levin et al. in 2014. Application of the method with the Single Particle Soot Photometer (SP2) is used to determine the effects of rBC on ice nucleating particles (INP). Here, we quantify the efficacy of the method in the laboratory usingmore » the rBC surrogate Aquadag. Polydisperse and mobility-selected samples (100–500 nm diameter, 0.44–36.05 fg), are quantified by a second SP2. Removal rates are reported by mass and number. For the mobility-selected samples, the average percentages removed by mass and number of the original size are 88.9 ± 18.6% and 87.3 ± 21.9%, respectively. Removal of Aquadag is efficient for particles >100 nm mass-equivalent diameter (dme), enabling application for microphysical studies. However, the removal of particles ≤100 nm dme is less efficient. Absorption and scattering measurements are reported to assess its use to isolate brown carbon (BrC) absorption. Scattering removal rates for the mobility-selected samples are >90% on average, yet absorption rates are 53% on average across all wavelengths. Therefore, application to isolate effects of microphysical properties determined by larger sizes is promising, but will be challenging for optical properties. Lastly, the results reported also have implications for other instruments employing internal LII, e.g., the Soot Particle Aerosol Mass Spectrometer (SP-AMS).« less

  10. Cone penetrometer fiber optic raman spectroscopy probe assembly

    DOE Patents [OSTI]

    Kyle, Kevin R.; Brown, Steven B.

    2000-01-01

    A chemically and mechanically robust optical Raman spectroscopy probe assembly that can be incorporated in a cone penetrometer (CPT) for subsurface deployment. This assembly consists of an optical Raman probe and a penetrometer compatible optical probe housing. The probe is intended for in-situ chemical analysis of chemical constituents in the surrounding environment. The probe is optically linked via fiber optics to the light source and the detection system at the surface. A built-in broadband light source provides a strobe method for direct measurement of sample optical density. A mechanically stable sapphire window is sealed directly into the side-wall of the housing using a metallic, chemically resistant, hermetic seal design. This window permits transmission of the interrogation light beam and the resultant signal. The spectroscopy probe assembly is capable of accepting Raman, Laser induced Fluorescence, reflectance, and other optical probes with collimated output for CPT deployment.

  11. High-voltage atmospheric breakdown across intervening rutile dielectrics.

    SciTech Connect (OSTI)

    Williamson, Kenneth Martin; Simpson, Sean; Coats, Rebecca Sue; Jorgenson, Roy Eberhardt; Hjalmarson, Harold Paul; Pasik, Michael Francis

    2013-09-01

    This report documents work conducted in FY13 on electrical discharge experiments performed to develop predictive computational models of the fundamental processes of surface breakdown in the vicinity of high-permittivity material interfaces. Further, experiments were conducted to determine if free carrier electrons could be excited into the conduction band thus lowering the effective breakdown voltage when UV photons (4.66 eV) from a high energy pulsed laser were incident on the rutile sample. This report documents the numerical approach, the experimental setup, and summarizes the data and simulations. Lastly, it describes the path forward and challenges that must be overcome in order to improve future experiments for characterizing the breakdown behavior for rutile.

  12. Laser-Induced Fluorescence

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing ... Heavy Duty Fuels DISI Combustion HCCISCCI Fundamentals Spray Combustion Modeling ...

  13. Laser-Induced Fluorescence

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Induced Fluorescence - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced Nuclear

  14. A relationship between statistical time to breakdown distributions and pre-breakdown negative differential resistance at nanometric scale

    SciTech Connect (OSTI)

    Foissac, R.; Blonkowski, S.; Delcroix, P.; Kogelschatz, M.

    2014-07-14

    Using an ultra-high vacuum Conductive atomic force microscopy (C-AFM) current voltage, pre-breakdown negative differential resistance (NDR) characteristics are measured together with the time dependent dielectric breakdown (TDDB) distributions of Si/SiON (1.4 and 2.6?nm thick). Those experimental characteristics are systematically compared. The NDR effect is modelled by a conductive filament growth. It is showed that the Weibull TDDB statistic distribution scale factor is proportional to the growth rate of an individual filament and then has the same dependence on the electric field. The proportionality factor is a power law of the ratio between the surfaces of the CAFM tip and the filament's top. Moreover, it was found that, for the high fields used in those experiments, the TDDB acceleration factor as the growth rate characteristic is proportional to the Zener tunnelling probability. Those observations are discussed in the framework of possible breakdown or forming mechanism.

  15. Laser-induced damage of intrinsic and extrinsic defects by picosecond pulses on multilayer dielectric coatings for petawatt-class lasers

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Negres, Raluca A.; Carr, Christopher W.; Laurence, Ted A.; Stanion, Ken; Guss, Gabe; Cross, David A.; Wegner, Paul J.; Stolz, Christopher J.

    2016-08-01

    Here, we describe a damage testing system and its use in investigating laser-induced optical damage initiated by both intrinsic and extrinsic precursors on multilayer dielectric coatings suitable for use in high-energy, large-aperture petawatt-class lasers. We employ small-area damage test methodologies to evaluate the intrinsic damage resistance of various coatings as a function of deposition methods and coating materials under simulated use conditions. In addition, we demonstrate that damage initiation by raster scanning at lower fluences and growth threshold testing are required to probe the density of extrinsic defects, which will limit large-aperture optics performance.

  16. (Tenth international conference on conduction and breakdown in dielectric liquids)

    SciTech Connect (OSTI)

    Christophorou, L.G.

    1990-10-05

    The traveler attended the 10th International Conference on Conduction and Breakdown in dielectric Liquids held in Grenoble, France, September 10--14, 1990. He chaired the opening session of the conference, presented one paper, co-authored a second paper presented at the meeting, participated in the discussions during the formal sessions, and had informal discussions with many of the participants.

  17. RF breakdown of 805 MHz cavities in strong magnetic fields

    SciTech Connect (OSTI)

    Bowring, D.; Stratakis, D.; Kochemirovskiy, A.; Leonova, M.; Moretti, A.; Palmer, M.; Peterson, D.; Yonehara, K.; Freemire, B.; Lane, P.; Torun, Y.; Haase, A.

    2015-05-03

    Ionization cooling of intense muon beams requires the operation of high-gradient, normal-conducting RF structures in the presence of strong magnetic fields. We have measured the breakdown rate in several RF cavities operating at several frequencies. Cavities operating within solenoidal magnetic fields B > 0.25 T show an increased RF breakdown rate at lower gradients compared with similar operation when B = 0 T. Ultimately, this breakdown behavior limits the maximum safe operating gradient of the cavity. Beyond ionization cooling, this issue affects the design of photoinjectors and klystrons, among other applications. We have built an 805 MHz pillbox-type RF cavity to serve as an experimental testbed for this phenomenon. This cavity is designed to study the problem of RF breakdown in strong magnetic fields using various cavity materials and surface treatments, and with precise control over sources of systematic error. We present results from tests in which the cavity was run with all copper surfaces in a variety of magnetic fields.

  18. The development and deployment of a ground-based, laser-induced fluorescence instrument for the in situ detection of iodine monoxide radicals

    SciTech Connect (OSTI)

    Thurlow, M. E. Hannun, R. A.; Lapson, L. B.; Anderson, J. G.; Co, D. T.; Argonne-Northwestern Solar Energy Research Center and Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113 ; O'Brien, A. S.; Department of Civil and Environmental Engineering, Princeton University, Princeton, New Jersey 08544 ; Hanisco, T. F.; NASA Goddard Space Flight Center, Code 614, Greenbelt, Maryland 20771

    2014-04-15

    High abundances of iodine monoxide (IO) are known to exist and to participate in local photochemistry of the marine boundary layer. Of particular interest are the roles IO plays in the formation of new particles in coastal marine environments and in depletion episodes of ozone and mercury in the Arctic polar spring. This paper describes a ground-based instrument that measures IO at mixing ratios less than one part in 10{sup 12}. The IO radical is measured by detecting laser-induced fluorescence at wavelengths longer that 500 nm. Tunable visible light is used to pump the A{sup 2}Π{sub 3/2} (v{sup ′} = 2) ← X{sup 2}Π{sub 3/2} (v{sup ″} = 0) transition of IO near 445 nm. The laser light is produced by a solid-state, Nd:YAG-pumped Ti:Sapphire laser at 5 kHz repetition rate. The laser-induced fluorescence instrument performs reliably with very high signal-to-noise ratios (>10) achieved in short integration times (<1 min). The observations from a validation deployment to the Shoals Marine Lab on Appledore Island, ME are presented and are broadly consistent with in situ observations from European Coastal Sites. Mixing ratios ranged from the instrumental detection limit (<1 pptv) to 10 pptv. These data represent the first in situ point measurements of IO in North America.

  19. Nanosecond laser-induced damage at different initial temperatures of Ta{sub 2}O{sub 5} films prepared by dual ion beam sputtering

    SciTech Connect (OSTI)

    Xu, Cheng Jia, Jiaojiao; Fan, Heliang; Qiang, Yinghuai; Liu, Jiongtian; Yang, Di; Hu, Guohang; Li, Dawei

    2014-08-07

    Ta{sub 2}O{sub 5} films were deposited by dual ion beam sputtering method. The nanosecond laser-induced damage threshold (LIDT) at different initial temperatures and time of the films was investigated by an in situ high temperature laser-induced damage testing platform. It was shown that, when the initial temperature increased from 298 K to 383 K, the LIDT at 1064 nm and 12 ns significantly decreased by nearly 14%. Then the LIDT at 1064 nm and 12 ns decreased slower with the same temperature increment. Different damage morphologies were found at different initial temperatures. At low initial temperatures, it was the defects-isolated damage while at high initial temperatures it was the defects-combined damage. The theoretical calculations based on the defect-induced damage model revealed that both the significant increase of the highest temperature and the duration contributed to the different damage morphologies. With the initial temperature being increased, the thermal-stress coupling damage mechanism transformed gradually to the thermal dominant damage mechanism.

  20. Characteristics of the dynamics of breakdown filaments in Al{sub 2}O{sub 3}/InGaAs stacks

    SciTech Connect (OSTI)

    Palumbo, F.; Shekhter, P.; Eizenberg, M.; Cohen Weinfeld, K.

    2015-09-21

    In this paper, the Al{sub 2}O{sub 3}/InGaAs interface was studied by X-ray photoelectron spectroscopy (XPS) after a breakdown (BD) event at positive bias applied to the gate contact. The dynamics of the BD event were studied by comparable XPS measurements with different current compliance levels during the BD event. The overall results show that indium atoms from the substrate move towards the oxide by an electro-migration process and oxidize upon arrival following a power law dependence on the current compliance of the BD event. Such a result reveals the physical feature of the breakdown characteristics of III-V based metal-oxide-semiconductor devices.

  1. Laser-induced magnetic fields in ICF capsules, Final Report, DE-FG02-08ER85128, Phase 1

    SciTech Connect (OSTI)

    Lindman, Erick L

    2009-11-05

    Laser-induced magnetic fields in ICF capsules Final Report, DE-FG02-08ER85128, Phase 1 E. L. LINDMAN, Otowi Technical Services, Los Alamos, NM. The performance of an inertial-confinement-fusion (ICF) capsule can be improved by inserting a magnetic field into it before compressing it [Kirkpatrick, et al., Fusion Technol. 27, 205 (1995)]. To obtain standoff in an ICF power generator, a method of inserting the field without the use of low-inductance leads attached to the capsule is desired. A mechanism for generating such a field using a laser was discovered in Japan [Sakagami, et al., Phys. Rev. Lett. 42, 839 (1979), Kolodner and Yablonovitch, Phys. Rev. Lett. 43, 1402 (1979)] and studied at Los Alamos in the 1980s [M. A. Yates, et al., Phys. Rev. Lett. 49, 1702 (1982); Forslund and Brackbill, Phys. Rev. Lett. 48, 1614 (1982)]. In this mechanism, a p-polarized laser beam strikes a solid target producing hot electrons that are accelerated away from the target surface by resonant absorption. An electric field is created that returns the hot electrons to the target. But, they do not return to the target along the same trajectory on which they left. The resulting current produces a toroidal magnetic field that was observed to spread over a region outside the hot spot with a radius of a millimeter. No experimental measurements of the magnetic field strength were performed. Estimates from computer simulation suggest that field strengths in the range of 1 to 10 Mega gauss (100 to 1000 Tesla) were obtained outside of the laser spot. To use this mechanism to insert a magnetic field into an ICF capsule, the capsule must be redesigned. In one approach, a central conductor is added, a toroidal gap is cut in the outer wall and the DT fuel is frozen on the inner surface of the capsule. The capsule is dropped into the reaction chamber and struck first with the laser that generates the magnetic field. The laser hot spot is positioned at the center of the toroidal gap. As the

  2. Femtosecond laser-induced phase transformations in amorphous Cu{sub 77}Ni{sub 6}Sn{sub 10}P{sub 7} alloy

    SciTech Connect (OSTI)

    Zhang, Y.; Zou, G.; Wu, A.; Bai, H.; Liu, L.; Chen, N.; Zhou, Y.

    2015-01-14

    In this study, the femtosecond laser-induced crystallization of CuNiSnP amorphous ribbons was investigated by utilizing an amplified Ti:sapphire laser system. X-ray diffraction and scanning electronic microscope were applied to examine the phase and morphology changes of the amorphous ribbons. Micromachining without crystallization, surface patterning, and selective crystallization were successfully achieved by changing laser parameters. Obvious crystallization occurred under the condition that the laser fluence was smaller than the ablation threshold, indicating that the structural evolution of the material depends strongly on the laser parameters. Back cooling method was used to inhibit heat accumulation; a reversible transformation between the disordered amorphous and crystalline phases can be achieved by using this method.

  3. Development of a two-line OH-laser-induced fluorescence thermometry diagnostics strategy for gas-phase temperature measurements in engines

    SciTech Connect (OSTI)

    Devillers, R.; Bruneaux, G.; Schulz, C

    2008-11-01

    This study aims at optimizing two-line OH thermometry strategies for in-cylinder measurement in internal combustion engines. Various aspects are investigated experimentally, such as the selection of suitable OH lines and the possibility of using a single calibration coefficient for variable mixture composition, temperature, and pressure conditions. Two kinds of experimental systems have been investigated. First, a laminar methane-air burner flame at atmospheric pressure, whose stability allowed the determination of OH-laser-induced fluorescence (LIF) intensity ratios from nonsimultaneous imaging. The temperature distribution in the flame is presented for OH-transition pairs with various temperature sensitivities. The burner flame was studied for equivalence ratios from {phi}=0.93 to 1.30 in order to check for the stability of calibration over various flame conditions. Additionally, OH LIF images were acquired in an optical engine for the chosen OH transitions yielding data about the effect of pressure on OH LIF signals under realistic experimental conditions.

  4. Investigation of thermodynamic equilibrium in laser-induced aluminum plasma using the H{sub α} line profiles and Thomson scattering spectra

    SciTech Connect (OSTI)

    Cvejić, M. E-mail: krzysztof.dzierzega@uj.edu.pl; Dzierżęga, K. E-mail: krzysztof.dzierzega@uj.edu.pl; Pięta, T.

    2015-07-13

    We have studied isothermal equilibrium in the laser-induced plasma from aluminum pellets in argon at pressure of 200 mbar by using a method which combines the standard laser Thomson scattering and analysis of the H{sub α}, Stark-broadened, line profiles. Plasma was created using 4.5 ns, 4 mJ pulses from a Nd:YAG laser at 1064 nm. While electron density and temperature were determined from the electron feature of Thomson scattering spectra, the heavy particle temperature was obtained from the H{sub α} full profile applying computer simulation including ion-dynamical effects. We have found strong imbalance between these two temperatures during entire plasma evolution which indicates its non-isothermal character. At the same time, according to the McWhirter criterion, the electron density was high enough to establish plasma in local thermodynamic equilibrium.

  5. The effect of pulse duration on the growth rate of laser-induced damage sites at 351 nm on fused silica surfaces

    SciTech Connect (OSTI)

    Negres, R A; Norton, M A; Liao, Z M; Cross, D A; Bude, J D; Carr, C W

    2009-10-29

    Past work in the area of laser-induced damage growth has shown growth rates to be primarily dependent on the laser fluence and wavelength. More recent studies suggest that growth rate, similar to the damage initiation process, is affected by a number of additional parameters including pulse duration, pulse shape, site size, and internal structure. In this study, we focus on the effect of pulse duration on the growth rate of laser damage sites located on the exit surface of fused silica optics. Our results demonstrate, for the first time, a significant dependence of growth rate at 351 nm on pulse duration from 1 ns to 15 ns as {tau}{sup 0.3} for sites in the 50-100 {micro}m size range.

  6. Generation of ultra-high-pressure shocks by collision of a fast plasma projectile driven in the laser-induced cavity pressure acceleration scheme with a solid target

    SciTech Connect (OSTI)

    Badziak, J.; Rosiński, M.; Krousky, E.; Kucharik, M.; Liska, R.; Ullschmied, J.

    2015-03-15

    A novel, efficient method of generating ultra-high-pressure shocks is proposed and investigated. In this method, the shock is generated by collision of a fast plasma projectile (a macro-particle) driven by laser-induced cavity pressure acceleration (LICPA) with a solid target placed at the LICPA accelerator channel exit. Using the measurements performed at the kilojoule PALS laser facility and two-dimensional hydrodynamic simulations, it is shown that the shock pressure ∼ Gbar can be produced with this method at the laser driver energy of only a few hundred joules, by an order of magnitude lower than the energy needed for production of such pressure with other laser-based methods known so far.

  7. CoverSheet

    Office of Scientific and Technical Information (OSTI)

    N C L A S S I F I E D 42 42 Slide 42 Venus Surface and Atmosphere Geochemical Explorer (SAGE) Remote Raman & Laser-Induced Breakdown Spectroscopy (LIBS) U N C L A S S I F I E D U N...

  8. PHENIX Work Breakdown Structure. Cost and schedule review copy

    SciTech Connect (OSTI)

    Not Available

    1994-02-01

    The Work Breakdown Structure (WBS) Book begins with this Overview section, which contains the high-level summary cost estimate, the cost profile, and the global construction schedule. The summary cost estimate shows the total US cost and the cost in terms of PHENIX construction funds for building the PHENIX detector. All costs in the WBS book are shown in FY 1993 dollars. Also shown are the institutional and foreign contributions, the level of pre-operations funding, and the cost of deferred items. Pie charts are presented at PHENIX WBS level 1 and 2 that show this information. The PHENIX construction funds are shown broken down to PHENIX WBS level 3 items per fiscal year, and the resulting profile is compared to the RHIC target profile. An accumulated difference of the two profiles is also shown. The PHENIX global construction schedule is presented at the end of the Overview section. Following the Overview are sections for each subsystem. Each subsystem section begins with a summary cost estimate, cost profile, and critical path. The total level 3 cost is broken down into fixed costs (M&S), engineering costs (EDIA) and labor costs. Costs are further broken down in terms of PHENIX construction funds, institutional and foreign contributions, pre-operations funding, and deferred items. Also shown is the contingency at level 3 and the level 4 breakdown of the total cost. The cost profile in fiscal years is shown at level 3. The subsystem summaries are followed by the full cost estimate and schedule sheets for that subsystem. These detailed sheets are typically carried down to level 7 or 8. The cost estimate shows Total, M&S, EDIA, and Labor breakdowns, as well as contingency, for each WBS entry.

  9. Asymmetric Bimodal Accelerator Cavity for Raising rf Breakdown Thresholds

    SciTech Connect (OSTI)

    Kuzikov, S. V.; Kazakov, S. Yu.; Jiang, Y.; Hirshfield, J. L.

    2010-05-28

    We consider an axisymmetric microwave cavity for an accelerator structure whose eigenfrequency for its second lowest TM-like axisymmetric mode is twice that of the lowest such mode, and for which the fields are asymmetric along its axis. In this cavity, the peak amplitude of the rf electric field that points into either longitudinal face can be smaller than the peak field which points out. Computations show that a structure using such cavities might support an accelerating gradient about 47% greater than that for a structure using similar single-mode cavities, without an increase in breakdown probability.

  10. Gas breakdown driven by L band short-pulse high-power microwave

    SciTech Connect (OSTI)

    Yang Yiming; Yuan Chengwei; Qian Baoliang

    2012-12-15

    High power microwave (HPM) driven gas breakdown is a major factor in limiting the radiation and transmission of HPM. A method that HPM driven gas breakdown could be obtained by changing the aperture of horn antenna is studied in this paper. Changing the effective aperture of horn antenna can adjust the electric field in near field zone, leading to gas breakdown. With this method, measurements of air and SF{sub 6} breakdowns are carried out on a magnetically insulated transmission-line oscillators, which is capable of generating HPM with pulse duration of 30 ns, and frequency of 1.74 GHz. The typical breakdown waveforms of air and SF{sub 6} are presented. Besides, the breakdown field strengths of the two gases are derived at different pressures. It is found that the effects of air and SF{sub 6} breakdown on the transmission of HPM are different: air breakdown mainly shortens the pulse width of HPM while SF{sub 6} breakdown mainly reduces the peak output power of HPM. The electric field threshold of SF{sub 6} is about 2.4 times larger than that of air. These differences suggest that gas properties have a great effect on the transmission characteristic of HPM in gases.

  11. Studies on gas breakdown in pulsed radio frequency atmospheric pressure glow discharges

    SciTech Connect (OSTI)

    Huo, W. G. [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China) [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China); School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029 (China); Jian, S. J.; Yao, J.; Ding, Z. F., E-mail: zfding@dlut.edu.cn [School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116023 (China)

    2014-05-15

    In pulsed RF atmospheric pressure glow discharges, the gas breakdown judged by the rapid drop in the amplitude of the pulsed RF voltage is no longer universally true. The steep increment of the plasma-absorbed RF power is proposed to determine the gas breakdown. The averaged plasma-absorbed RF power over a pulse period is used to evaluate effects of the preceding pulsed RF discharge on the breakdown voltage of the following one, finding that the breakdown voltage decreases with the increment in the averaged plasma-absorbed RF power under constant pulse duty ratio. Effects of the pulse off-time on the breakdown voltage and the breakdown delay time are also studied. The obtained dependence of the breakdown voltage on the pulse off-time is indicative of the transitional plasma diffusion processes in the afterglow. The breakdown voltage varies rapidly as the plasma diffuses fast in the region of moderate pulse off-time. The contribution of nitrogen atom recombination at the alumina surface is demonstrated in the prolonged memory effect on the breakdown delay time vs. the pulse off-time and experimentally validated by introducing a trace amount of nitrogen into argon at short and long pulse off-times.

  12. Visual and Electrical Evidence Supporting a Two-Plasma Mechanism of Vacuum Breakdown Initiation

    SciTech Connect (OSTI)

    Castano-Giraldo, C.; Aghazarian, Maro; Caughman, John B; Ruzic, D. N.

    2012-01-01

    The energy available during vacuum breakdown between copper electrodes at high vacuum was limited using resistors in series with the vacuum gap and arresting diodes. Surviving features observed with SEM in postmortem samples were tentatively correlated with electrical signals captured during breakdown using a Rogowski coil and a high-voltage probe. The visual and electrical evidence is consistent with the qualitative model of vacuum breakdown by unipolar arc formation by Schwirzke [1, 2]. The evidence paints a picture of two plasmas of different composition and scale being created during vacuum breakdown: an initial plasma made of degassed material from the metal surface, ignites a plasma made up of the electrode material.

  13. Breakdown in hydrogen and deuterium gases in static and radio-frequency fields

    SciTech Connect (OSTI)

    Korolov, I. Donkó, Z.

    2015-09-15

    We report the results of a combined experimental and modeling study of the electrical breakdown of hydrogen and deuterium in static (DC) and radio-frequency (RF) (13.56 MHz) electric fields. For the simulations of the breakdown events, simplified models are used and only electrons are traced by Monte Carlo simulation. The experimental DC Paschen curve of hydrogen is used for the determination of the effective secondary electron emission coefficient. A very good agreement between the experimental and the calculated RF breakdown characteristics for hydrogen is found. For deuterium, on the other hand, presently available cross section sets do not allow a reproduction of RF breakdown characteristics.

  14. Scaling law for direct current field emission-driven microscale gas breakdown

    SciTech Connect (OSTI)

    Venkattraman, A.; Alexeenko, A. A.

    2012-12-15

    The effects of field emission on direct current breakdown in microscale gaps filled with an ambient neutral gas are studied numerically and analytically. Fundamental numerical experiments using the particle-in-cell/Monte Carlo collisions method are used to systematically quantify microscale ionization and space-charge enhancement of field emission. The numerical experiments are then used to validate a scaling law for the modified Paschen curve that bridges field emission-driven breakdown with the macroscale Paschen law. Analytical expressions are derived for the increase in cathode electric field, total steady state current density, and the ion-enhancement coefficient including a new breakdown criterion. It also includes the effect of all key parameters such as pressure, operating gas, and field-enhancement factor providing a better predictive capability than existing microscale breakdown models. The field-enhancement factor is shown to be the most sensitive parameter with its increase leading to a significant drop in the threshold breakdown electric field and also to a gradual merging with the Paschen law. The proposed scaling law is also shown to agree well with two independent sets of experimental data for microscale breakdown in air. The ability to accurately describe not just the breakdown voltage but the entire pre-breakdown process for given operating conditions makes the proposed model a suitable candidate for the design and analysis of electrostatic microscale devices.

  15. Breakdown of semiclassical methods in de Sitter space

    SciTech Connect (OSTI)

    Burgess, C.P.; Holman, R.; Leblond, L.; Shandera, S. E-mail: rh4a@andrew.cmu.edu E-mail: sshandera@perimeterinstitute.ca

    2010-10-01

    Massless interacting scalar fields in de Sitter space have long been known to experience large fluctuations over length scales larger than Hubble distances. A similar situation arises in condensed matter physics in the vicinity of a critical point, and in this better-understood situation these large fluctuations indicate the failure in this regime of mean-field methods. We argue that for non-Goldstone scalars in de Sitter space, these fluctuations can also be interpreted as signaling the complete breakdown of the semi-classical methods widely used throughout cosmology. By power-counting the infrared properties of Feynman graphs in de Sitter space we find that for a massive scalar interacting through a λ φ{sup 4} interaction, control over the loop approximation is lost for masses smaller than m ≅ √λ H/2π, where H is the Hubble scale. We briefly discuss some potential implications for inflationary cosmology.

  16. Dynamics of optical breakdown in air induced by single and double nanosecond laser pulses

    SciTech Connect (OSTI)

    Mahdieh, Mohammad Hossein Akbari Jafarabadi, Marzieh

    2015-12-15

    In this paper, an optical breakdown in air induced by single and double nanosecond laser pulses was studied. A high power Nd:YAG laser beam was used for producing optical breakdown plasma in the air. The dynamics of breakdown plasma were studied using an optical probe beam. A portion of the laser beam was used, as the probe beam and was aligned to propagate (perpendicular to the pump beam) through the breakdown region. The transmission of the probe beam (through the breakdown region) was temporally measured for both single and double pulse irradiations. The results were used to describe the evolution of the induced plasma in both conditions. These results show that the plasma formation time and its absorptivity are strongly dependent on the single or double pulse configurations.

  17. Review of recent theories and experiments for improving high-power microwave window breakdown thresholds

    SciTech Connect (OSTI)

    Chang Chao; Liu Guozhi; Tang Chuanxiang; Chen Changhua; Fang Jinyong

    2011-05-15

    Dielectric window breakdown is a serious challenge in high-power microwave (HPM) transmission and radiation. Breakdown at the vacuum/dielectric interface is triggered by multipactor and finally realized by plasma avalanche in the ambient desorbed or evaporated gas layer above the dielectric. Methods of improving breakdown thresholds are key challenges in HPM systems. First, the main theoretical and experimental progress is reviewed. Next, the mechanisms of multipactor suppression for periodic rectangular and triangular surface profiles by dynamic analysis and particle-in-cell simulations are surveyed. Improved HPM breakdown thresholds are demonstrated by proof-of-principle and multigigawatt experiments. The current theories and experiments of using dc magnetic field to resonantly accelerate electrons to suppress multipactor are also synthesized. These methods of periodic profiles and magnetic field may solve the key issues of HPM vacuum dielectric breakdown.

  18. Electric properties and carrier multiplication in breakdown sites in multi-crystalline silicon solar cells

    SciTech Connect (OSTI)

    Schneemann, Matthias; Carius, Reinhard; Rau, Uwe; Kirchartz, Thomas

    2015-05-28

    This paper studies the effective electrical size and carrier multiplication of breakdown sites in multi-crystalline silicon solar cells. The local series resistance limits the current of each breakdown site and is thereby linearizing the current-voltage characteristic. This fact allows the estimation of the effective electrical diameters to be as low as 100 nm. Using a laser beam induced current (LBIC) measurement with a high spatial resolution, we find carrier multiplication factors on the order of 30 (Zener-type breakdown) and 100 (avalanche breakdown) as new lower limits. Hence, we prove that also the so-called Zener-type breakdown is followed by avalanche multiplication. We explain that previous measurements of the carrier multiplication using thermography yield results higher than unity, only if the spatial defect density is high enough, and the illumination intensity is lower than what was used for the LBIC method. The individual series resistances of the breakdown sites limit the current through these breakdown sites. Therefore, the measured multiplication factors depend on the applied voltage as well as on the injected photocurrent. Both dependencies are successfully simulated using a series-resistance-limited diode model.

  19. A study of dielectric breakdown along insulators surrounding conductors in liquid argon

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lockwitz, Sarah; Jostlein, Hans

    2016-03-22

    High voltage breakdown in liquid argon is an important concern in the design of liquid argon time projection chambers, which are often used as neutrino and dark matter detectors. We have made systematic measurements of breakdown voltages in liquid argon along insulators surrounding negative rod electrodes where the breakdown is initiated at the anode. The measurements were performed in an open cryostat filled with commercial grade liquid argon exposed to air, and not the ultra-pure argon required for electron drift. While not addressing all high voltage concerns in liquid argon, these measurements have direct relevance to the design of highmore » voltage feedthroughs especially for averting the common problem of flash-over breakdown. The purpose of these tests is to understand the effects of materials, of breakdown path length, and of surface topology for this geometry and setup. We have found that the only material-specific effects are those due to their permittivity. We have found that the breakdown voltage has no dependence on the length of the exposed insulator. Lastly, a model for the breakdown mechanism is presented that can help inform future designs.« less

  20. Analytical investigation of electrical breakdown properties in a nitrogen-SF{sub 6} mixture gas

    SciTech Connect (OSTI)

    Uhm, Han S.; Byeon, Yong S.; Song, Ki B.; Choi, Eun H.; Ryu, Han-Yong; Lee, Jaimin

    2010-11-15

    The electrical breakdown properties in nitrogen gas mixed with SF{sub 6} are analytically investigated in this article by making use of the ionization and attachment coefficients of the mixed gas. The ionization coefficients of nitrogen and SF{sub 6} gas are obtained in terms of the electron temperature T{sub e} by assuming a Maxwellian distribution of the electron energy. The attachment coefficient of SF{sub 6} gas is also obtained in terms of the gas temperature T{sub e}. An algebraic equation is obtained, relating explicitly the electron breakdown temperature T{sub b} in terms of the SF{sub 6} mole fraction {chi}. It was found from this equation that the breakdown temperature T{sub b} increases from approximately 2 to 5.3 eV as the mole fraction {chi} increases from zero to unity. The breakdown temperature T{sub b} of the electrons increases very rapidly from a small value and then approaches 5.3 eV slowly as the SF{sub 6} mole fraction increases from zero to unity. This indicates that even a small mole fraction of SF{sub 6} in the gas dominates the electron behavior in the breakdown system. The breakdown electric field E{sub b} derived is almost linearly proportional to the breakdown electron temperature T{sub b}. The experimental data agree remarkably well with the theoretical results. Therefore, it is concluded that even a small fraction of SF{sub 6} gas dominates nitrogen in determining the breakdown field. In this context, nearly 25% of the SF{sub 6} mole fraction provides a reasonable enhancement of the breakdown field for practical applications.

  1. Experimental investigation of breakdown voltage characteristics of single-gap and multigap pseudosparks

    SciTech Connect (OSTI)

    Liu, C.J.; Rhee, M.J.

    1995-06-01

    Simple empirical scaling laws that can be applied universally are determined for breakdown voltage characteristics of single-gap and multigap pseudosparks. For the single-gap pseudospark, the breakdown voltage is found to be a function of the product of the gas pressure squared, the anode-cathode gap distance, and the hollow cavity diameter, p{sup 2}dD, and a function of the product pd for a gap distance less than and greater than three times the cavity diameter, respectively. For the multigap pseudospark, however, the breakdown voltage is found to be only a function of the product p{sup 2}dD.

  2. Can surface cracks and unipolar arcs explain breakdown and gradient limits?

    SciTech Connect (OSTI)

    Insepov, Zeke; Norem, Jim

    2013-01-15

    The authors argue that the physics of unipolar arcs and surface cracks can help understand rf breakdown and vacuum arc data. They outline a model of the basic mechanisms involved in breakdown and explore how the physics of unipolar arcs and cracks can simplify the picture of breakdown and gradient limits in accelerators, tokamaks as well as laser ablation, micrometeorites, and other applications. Cracks are commonly seen in SEM images of arc damage and they are produced as the liquid metal cools. They can produce the required field enhancements to explain field emission data and can produce mechanical failure of the surface that would trigger breakdown events. Unipolar arcs can produce currents sufficient to short out rf structures, and can cause the sort of damage seen in SEM images. They should be unstable, and possibly self-quenching, as seen in optical fluctuations and surface damage. The authors describe some details and consider the predictions of this simple model.

  3. Where do the default values for the cost of system breakdowns...

    Open Energy Info (EERE)

    Where do the default values for the cost of system breakdowns come from in SAM, for direct and indirect costs, such as 0.63 per DC watt for panels. 0.18 for inverters. Are these...

  4. Laser Enables Inexpensive Elemental Analysis | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laser Enables Inexpensive Elemental Analysis New Laser Enables Inexpensive but Flexible Elemental Analysis Laser induced breakdown spectroscopy, or LIBS, is a type of atomic emission spectroscopy. LIBS operates by focusing the laser onto a small area at the surface of the specimen; when the laser is discharged it ablates (vaporizes) a very small amount of material, in the range of nanograms to picograms, which generates a plasma plume with temperatures in excess of 10,000 K. There is a short

  5. Effects of load voltage on voltage breakdown modes of electrical exploding aluminum wires in air

    SciTech Connect (OSTI)

    Wu, Jian; Li, Xingwen Yang, Zefeng; Wang, Kun; Chao, Youchuang; Shi, Zongqian; Jia, Shenli; Qiu, Aici

    2015-06-15

    The effects of the load voltage on the breakdown modes are investigated in exploding aluminum wires driven by a 1 kA, 0.1 kA/ns pulsed current in air. From laser probing images taken by laser shadowgraphy, schlieren imaging, and interferometry, the position of the shockwave front, the plasma channel, and the wire core edge of the exploding product can be determined. The breakdown mode makes a transition from the internal mode, which involves breakdown inside the wire core, to the shunting mode, which involves breakdown in the compressed air, with decreasing charging voltage. The breakdown electrical field for a gaseous aluminum wire core of nearly solid density is estimated to be more than 20 kV/cm, while the value for gaseous aluminum of approximately 0.2% solid density decreases to 15–20 kV/cm. The breakdown field in shunting mode is less than 20 kV/cm and is strongly affected by the vaporized aluminum, the desorbed gas, and the electrons emitted from the wire core during the current pause. Ohmic heating during voltage collapses will induce further energy deposition in the current channel and thus will result in different expansion speeds for both the wire core and the shockwave front in the different modes.

  6. Laser-induced incandescence (LII)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... Mountain Gondola to see the amazing views of the mountain and the lake at the top. ... folklore, statistics, landmarks, beaches, movies, and secret sports of Lake Tahoe. ...

  7. Laser induced phosphorescence uranium analysis

    DOE Patents [OSTI]

    Bushaw, B.A.

    1983-06-10

    A method is described for measuring the uranium content of aqueous solutions wherein a uranyl phosphate complex is irradiated with a 5 nanosecond pulse of 425 nanometer laser light and resultant 520 nanometer emissions are observed for a period of 50 to 400 microseconds after the pulse. Plotting the natural logarithm of emission intensity as a function of time yields an intercept value which is proportional to uranium concentration.

  8. Laser induced phosphorescence uranium analysis

    DOE Patents [OSTI]

    Bushaw, Bruce A.

    1986-01-01

    A method is described for measuring the uranium content of aqueous solutions wherein a uranyl phosphate complex is irradiated with a 5 nanosecond pulse of 425 nanometer laser light and resultant 520 nanometer emissions are observed for a period of 50 to 400 microseconds after the pulse. Plotting the natural logarithm of emission intensity as a function of time yields an intercept value which is proportional to uranium concentration.

  9. Laser-induced incandescence (LII)

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    induced incandescence (LII) - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced

  10. Heterodyne laser spectroscopy system

    DOE Patents [OSTI]

    Wyeth, Richard W.; Paisner, Jeffrey A.; Story, Thomas

    1989-01-01

    A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency and the like, and provides spectral analysis of a laser beam.

  11. Heterodyne laser spectroscopy system

    DOE Patents [OSTI]

    Wyeth, Richard W.; Paisner, Jeffrey A.; Story, Thomas

    1990-01-01

    A heterodyne laser spectroscopy system utilizes laser heterodyne techniques for purposes of laser isotope separation spectroscopy, vapor diagnostics, processing of precise laser frequency offsets from a reference frequency, and provides spectral analysis of a laser beam.

  12. High stored-energy breakdown tests on electrodes made of stainless steel, copper, titanium and molybdenum

    SciTech Connect (OSTI)

    Esch, H. P. L. de Simonin, A.; Grand, C.

    2015-04-08

    IRFM have conducted resilience tests on electrodes made of Cu, stainless steel 304L, Ti and Mo against breakdowns up to 170 kV and 300 J. The tests of the 10×10 cm{sup 2} electrodes have been performed at an electrode distance d=11 mm under vacuum (P∼5×10{sup −6} mbar). No great difference in voltage holding between the materials could be identified; all materials could reach a voltage holding between 140 and 170 kV over the 11 mm gap, i.e. results scatter within a ±10% band. After exposure to ∼10000 seconds of high-voltage (HV) on-time, having accumulated ∼1000 breakdowns, the electrodes were inspected. The anodes were covered with large and small craters. The rugosity of the anodes had increased substantially, that of the cathodes to a lesser extent. The molybdenum electrodes are least affected, but this does not show in their voltage holding capability. It is hypothesized that penetrating high-energy electrons from the breakdown project heat below the surface of the anode and cause a micro-explosion of material when melting point is exceeded. Polished electrodes have also been tested. The polishing results in a substantially reduced breakdown rate in the beginning, but after having suffered a relatively small number (∼100) of breakdowns, the polished electrodes behaved the same as the unpolished ones.

  13. Electrical Breakdown Physics in Photoconductive Semiconductor Switches (PCSS).

    SciTech Connect (OSTI)

    Mar, Alan; Zutavern, Fred J.; Vawter, Gregory A.; Hjalmarson, Harold P.; Gallegos, Richard Joseph; Bigman, Verle Howard

    2016-01-01

    of 200kV (DC) and 5kA current that can be stacked in parallel to achieve 100's of kA with 10e5 shot lifetime. The new vertical switch design configuration generates parallel filaments in the bulk GaAs (as opposed to just beneath the surface as in previous designs) to achieve breakdown fields close to the maximum for the bulk GaAs while operating in air, and with 2-D scalability of the number of current-sharing filaments. This design also may be highly compatible with 2-D VCSEL arrays for optical triggering. The demonstration of this design in this LDRD utilized standard thickness wafers to trigger 0.4kA at 35kV/cm (limited by 0.6mm wafer thickness), tested to 1e5 shots with no detectable degradation of switch performance. Higher fields, total current, and switching voltages would be achievable with thicker GaAs wafers. Another important application pursued in this LDRD is the use of PCSS for trigger generator applications. Conventional in-plane PCSS have achieved triggering of a 100kV sparkgap (Kinetech-type) switch of the type similar to switches being considered for accelerator upgrades. The trigger is also being developed for pulsed power for HPM applications that require miniaturization and robust performance in noisy compact environments. This has spawned new programs for developing this technology, including an STTR for VCSEL trigger laser integration, also pursuing other follow-on applications.

  14. The quantum mechanics of ion-enhanced field emission and how it influences microscale gas breakdown

    SciTech Connect (OSTI)

    Li, Yingjie; Go, David B.

    2014-09-14

    The presence of a positive gas ion can enhance cold electron field emission by deforming the potential barrier and increasing the tunneling probability of electronsa process known as ion-enhanced field emission. In microscale gas discharges, ion-enhanced field emission produces additional emission from the cathode and effectively reduces the voltage required to breakdown a gaseous medium at the microscale (<10 ?m). In this work, we enhance classic field emission theory by determining the impact of a gaseous ion on electron tunneling and compute the effect of ion-enhanced field emission on the breakdown voltage. We reveal that the current density for ion-enhanced field emission retains the same scaling as vacuum cold field emission and that this leads to deviations from traditional breakdown theory at microscale dimensions.

  15. Single and repetitive short-pulse high-power microwave window breakdown

    SciTech Connect (OSTI)

    Chang, C.; Tang, C. X.; Shao, H.; Chen, C. H.; Huang, W. H.

    2010-05-15

    The mechanisms of high-power microwave breakdown for single and repetitive short pulses are analyzed. By calculation, multipactor saturation with electron density much higher than the critical plasma density is found not to result in microwave cutoff. It is local high pressure about Torr class that rapid plasma avalanche and final breakdown are realized in a 10-20 ns short pulse. It is found by calculation that the power deposited by saturated multipactor and the rf loss of protrusions are sufficient to induce vaporizing surface material and enhancing the ambient pressure in a single short pulse. For repetitive pulses, the accumulation of heat and plasma may respectively carbonize the surface material and lower the repetitive breakdown threshold.

  16. Acoustic effects at interaction of laser radiation with a liquid accompanied by optical breakdown

    SciTech Connect (OSTI)

    Bulanov, A. V.; Nagorny, I. G.

    2012-09-04

    The experimental researches of acoustic emission from optical breakdown in liquids are presented. Spectral characteristics and power of the acoustic waves generated in a liquid by optical breakdown at interaction of laser radiation with the wavelength of 532 nanometers were studied. It is shown, that two spectral maxima characterizing acoustic emission are observed. The shift of low-frequency maximum depending on the laser energy pulse is observed. As a whole, the linear dependence of acoustic pressure on the energy of laser pulse is observed. It is shown, that using acoustic data it is possible to reproduce function R(t) which will be in accord with characteristic dependences R(t), obtained from optical data. The last is especially important for breakdown studying in opaque environments.

  17. Breakdown assisted by a novel electron drift injection in the J-TEXT tokamak

    SciTech Connect (OSTI)

    Wang, Nengchao; Jin, Hai; Zhuang, Ge Ding, Yonghua; Pan, Yuan; Cen, Yishun; Chen, Zhipeng; Huang, Hai; Liu, Dequan; Rao, Bo; Zhang, Ming; Zou, Bichen

    2014-07-15

    A novel electron drift injection (EDI) system aiming to improve breakdown behavior has been designed and constructed on the Joint Texas EXperiment Tokamak Tokamak. Electrons emitted by the system undergo the EB drift, ?B drift and curvature drift in sequence in order to traverse the confining magnetic field. A local electrostatic well, generated by a concave-shaped plate biased more negative than the cathode, is introduced to interrupt the emitted electrons moving along the magnetic field line (in the parallel direction) in an attempt to bring an enhancement of the injection efficiency and depth. A series of experiments have demonstrated the feasibility of this method, and a penetration distance deeper than 9.5 cm is achieved. Notable breakdown improvements, including the reduction of breakdown delay and average loop voltage, are observed for discharges assisted by EDI. The lower limit of successfully ionized pressure is expanded.

  18. Study of the effect of properties of material on vacuum breakdown initiated by laser radiation

    SciTech Connect (OSTI)

    Seleznev, V. P.; Revazov, V. O.

    2015-12-15

    In this work, the effect of various properties of materials on vacuum breakdown initiated by laser radiation is considered. Estimating calculations are performed which show that the material of the target electrode distinctly affects the minimum energy of laser radiation needed for igniting a vacuum spark. The experimental studies carried out confirm the estimating calculations, and a number of materials are revealed which can be arranged in order of increase in the energy needed for the formation of breakdown in vacuum by the impact of a laser pulse.

  19. High resolution electronic spectroscopy of the A {sup 2}Σ{sup −} − X {sup 2}Π{sub 1/2} transition of PtN

    SciTech Connect (OSTI)

    Womack, Kaitlin; O’Brien, Leah C.; Whittemore, Sean; O’Brien, James J.; Le, Anh; Steimle, Timothy C.

    2014-08-28

    The (2,0) vibrational band of the A {sup 2}Σ{sup −} − X {sup 2}Π{sub 1/2} transition of platinum nitride, PtN, was recorded at Doppler-limited resolution using intracavity laser absorption spectroscopy (ILS) and at sub-Doppler resolution using molecular beam laser induced fluorescence (LIF) spectroscopy. Isotopologue structure for {sup 194}PtN, {sup 195}PtN, and {sup 196}PtN, magnetic hyperfine splitting due to {sup 195}Pt (I = ½), and nuclear quadrupole splitting due to {sup 14}N (I = 1) were observed in the spectrum. Molecular constants for the ground and excited states are derived. The hyperfine interactions are used to illuminate the nature of the A {sup 2}Σ{sup −} excited electronic state.

  20. Breakdown of Angular Momentum Selection Rules in High Pressure Optical Pumping Experiments

    SciTech Connect (OSTI)

    Lancor, B.; Wyllie, R.; Walker, T. G.; Babcock, E.

    2010-08-20

    We present measurements, by using two complementary methods, of the breakdown of atomic angular momentum selection rules in He-broadened Rb vapor. Atomic dark states are rendered weakly absorbing due to fine-structure mixing during Rb-He collisions. The effect substantially increases the photon demand for optical pumping of dense vapors.

  1. A Theory for the Comparative RF Surface Fields at Destructive Breakdown for Various Metels

    SciTech Connect (OSTI)

    Wilson, Perry; /SLAC

    2006-03-20

    By destructive breakdown we mean a breakdown event that results in surface melting over large areas on the iris tip region of an accelerator structure. The melting is the result of the formation of macroscopic areas of plasma in contact with the surface. The plasma bombards the surface with an intense ion current ({approx}10{sup 8} A/cm{sup 2}), which is equivalent to a pressure on the order of a thousand Atmospheres. A radial gradient in the pressure produces a ponderomotive force that causes molten copper to migrate away from the iris tip, resulting in a measurable change in the iris shape. This distortion in the iris shape in turn produces an error in the cell-to-cell phase shift of the accelerating wave with a consequent loss in synchronism with the electron beam and a reduction in the effective accelerating gradient. Assuming a long lifetime is desired for the structure, such breakdowns must be avoided or at least limited in number. The accelerating gradient at which these breakdowns begin to occur imposes, therefore, an absolute limit on an operationally attainable gradient. The destructive breakdown limit (DBL) on the accelerating gradient depends on a number of factors, such as the geometry of the irises and coupler, the accuracy of the cell-to-cell tuning (''field flatness''), and the properties of the metal used in the high E-field regions of the structure. In this note we consider only the question of the dependence of the DBL on the metal used in the high surface field areas of the structure. There are also various types of non-destructive breakdowns (NDB's) that occur during the ''processing'' period that, after the initial application of high power, is necessary to bring the gradient up to the desired operating level. During this period, as the input power and gradient are gradually increased, thousands of such NDB's occur. These breakdowns produce a collapse in the fields in the structure as energy stored in the fields is absorbed at the breakdown

  2. labNotes | netl.doe.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    LabNotes NETL Validates Innovative Spectrometry Technique libs-PIC.JPG Graphic representation of in situ measurements of calcium carbonate dissolution under rising CO2 pressure using underwater laser-induced breakdown spectroscopy. Image used as the front cover for the Journal of Analytical Atomic Spectrometry's July 2016 issue. An article highlighting NETL's research into the use of laser spectrometry to collect data vital to ensuring the efficacy and safety of geologic carbon storage sites was

  3. NREL: Measurements and Characterization - Reflectance Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... Photoluminescence Spectroscopy Minority-Carrier Lifetime Spectroscopy Fourier-Transform Infrared & Raman Spectroscopy Spectroscopic Ellipsometry Capacitance Techniques Scanning ...

  4. Transition between breakdown regimes in a temperature-dependent mixture of argon and mercury using 100 kHz excitation

    SciTech Connect (OSTI)

    Sobota, A.; Bos, R. A. J. M. van den; Kroesen, G. [Dept. of Applied Physics, Eindhoven University of Technology, Postbus 513, 5600MB Eindhoven (Netherlands); Manders, F. [Philips Innovative Applications, Steenweg op Gierle 417, B-2300 Turnhout (Belgium)

    2013-01-28

    The paper examines the breakdown process at 100 kHz in a changing temperature-dependent mixture of Ar and Hg and the associated transitions between breakdown regimes. Each measurement series started at 1400 K, 10 bar of Hg, and 0.05% admixture of Ar and finished by natural cooling at room temperature, 150 mbar of Ar, and 0.01% admixture of Hg. The E/N at breakdown as a function of temperature and gas composition was found to have a particular shape with a peak at 600 K, when Hg makes up for 66% of the gaseous mixture and Ar 34%. This peak was found to be an effect of the mixture itself, not the temperature effects or the possible presence of electronegative species. The analysis has shown that at this frequency both streamer and diffuse breakdown can take place, depending on the temperature and gas composition. Streamer discharges during breakdown are present at high temperatures and high Hg pressure, while at room temperature in 150 mbar of Ar the breakdown has a diffuse nature. In between those two cases, the radius of the discharges during breakdown was found to change in a monotonic manner, covering one order of magnitude from the size typical for streamer discharges to a diffuse discharge comparable to the size of the reactor.

  5. Photoemission Spectroscopy at SRI2013

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Photoemission Spectroscopy at SRI2013 Workshop on Photoemission Spectroscopy: The Upcoming Decades Organizers: Alexei Fedorov (ALS) and Peter Johnson (BNL) Tuesday, June 18, 2013 *...

  6. In-situ characterization of femtosecond laser-induced crystallization in borosilicate glass using time-resolved surface third-harmonic generation

    SciTech Connect (OSTI)

    Liu, Weimin; Wang, Liang; Han, Fangyuan; Fang, Chong

    2013-11-11

    Coherent phonon dynamics in condensed-phase medium are responsible for important material properties including thermal and electrical conductivities. We report a structural dynamics technique, time-resolved surface third-harmonic generation (TRSTHG) spectroscopy, to capture transient phonon propagation near the surface of polycrystalline CaF{sub 2} and amorphous borosilicate (BK7) glass. Our approach time-resolves the background-free, high-sensitivity third harmonic generation (THG) signal in between the two crossing near-IR pulses. Pronounced intensity quantum beats reveal the impulsively excited low-frequency Raman mode evolution on the femtosecond to picosecond timescale. After amplified laser irradiation, danburite-crystal-like structure units form at the glass surface. This versatile TRSTHG setup paves the way to mechanistically study and design advanced thermoelectrics and photovoltaics.

  7. Nonlinear Laser Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    ... Nonlinear optical techniques investigated in this program include time-resolved coherent anti-Stokes Raman spectroscopy, degenerate four-wave mixing, coherent 1D and 2D imaging ...

  8. Performance and breakdown characteristics of irradiated vertical power GaN P-i-N diodes

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    King, M. P.; Armstrong, A. M.; Dickerson, J. R.; Vizkelethy, G.; Fleming, R. M.; Campbell, J.; Wampler, W. R.; Kizilyalli, I. C.; Bour, D. P.; Aktas, O.; et al

    2015-10-29

    Electrical performance and defect characterization of vertical GaN P-i-N diodes before and after irradiation with 2.5 MeV protons and neutrons is investigated. Devices exhibit increase in specific on-resistance following irradiation with protons and neutrons, indicating displacement damage introduces defects into the p-GaN and n- drift regions of the device that impact on-state device performance. The breakdown voltage of these devices, initially above 1700 V, is observed to decrease only slightly for particle fluence <; 1013 cm-2. Furthermore, the unipolar figure of merit for power devices indicates that while the on-resistance and breakdown voltage degrade with irradiation, vertical GaN P-i-Ns remainmore » superior to the performance of the best available, unirradiated silicon devices and on-par with unirradiated modern SiC-based power devices.« less

  9. Liquid Argon Dielectric Breakdown Studies with the MicroBooNE Purification System

    SciTech Connect (OSTI)

    Acciarri, R.; Carls, B.; James, C.; Johnson, B.; Jostlein, H.; Lockwitz, S.; Lundberg, B.; Raaf, J. L.; Rameika, R.; Rebel, B.; Zeller, G. P.; Zuckerbrot, M.

    2014-11-04

    The proliferation of liquid argon time projection chamber detectors makes the characterization of the dielectric properties of liquid argon a critical task. To improve understanding of these properties, a systematic study of the breakdown electric field in liquid argon was conducted using a dedicated cryostat connected to the MicroBooNE cryogenic system at Fermilab. An electrode sphere-plate geometry was implemented using spheres with diameters of 1.3 mm, 5.0 mm, and 76 mm. The MicroBooNE cryogenic system allowed measurements to be taken at a variety of electronegative contamination levels ranging from a few parts-per-million to tens of parts-per-trillion. The cathode-anode distance was varied from 0.1 mm to 2.5 cm. The results demonstrate a geometric dependence of the electric field strength at breakdown. This study is the first time that the dependence of the breakdown field on stressed cathode area has been shown for liquid argon.

  10. Non-linear optical studies of adsorbates: Spectroscopy and dynamics

    SciTech Connect (OSTI)

    Zhu, Xiangdong.

    1989-08-01

    In the first part of this thesis, we have established a systematic procedure to apply the surface optical second-harmonic generation (SHG) technique to study surface dynamics of adsorbates. In particular, we have developed a novel technique for studies of molecular surface diffusions. In this technique, the laser-induced desorption with two interfering laser beams is used to produce a monolayer grating of adsorbates. The monolayer grating is detected with diffractions of optical SHG. By monitoring the first-order second-harmonic diffraction, we can follow the time evolution of the grating modulation from which we are able to deduce the diffusion constant of the adsorbates on the surface. We have successfully applied this technique to investigate the surface diffusion of CO on Ni(111). The unique advantages of this novel technique will enable us to readily study anisotropy of a surface diffusion with variable grating orientation, and to investigate diffusion processes of a large dynamic range with variable grating spacings. In the second part of this work, we demonstrate that optical infrared-visible sum-frequency generation (SFG) from surfaces can be used as a viable surface vibrational spectroscopic technique. We have successfully recorded the first vibrational spectrum of a monolayer of adsorbates using optical infrared-visible SFG. The qualitative and quantitative correlation of optical SFG with infrared absorption and Raman scattering spectroscopies are examined and experimentally demonstrated. We have further investigated the possibility to use transient infrared-visible SFG to probe vibrational transients and ultrafast relaxations on surfaces. 146 refs.

  11. Formation and direct writing of color centers in LiF using a laser-induced extreme ultraviolet plasma in combination with a Schwarzschild objective

    SciTech Connect (OSTI)

    Barkusky, Frank; Peth, Christian; Mann, Klaus; Feigl, Torsten; Kaiser, Norbert

    2005-10-15

    In order to generate high-energy densities of 13.5 nm radiation, an extreme ultraviolet (EUV) Schwarzschild mirror objective with a numerical aperture of 0.44 and a demagnification of 10 was developed and adapted to a compact laser-based EUV source. The annular spherical mirror substrates were coated with Mo/Si multilayer systems. With a single mirror reflectance of more than 65% the total transmittance of the Schwarzschild objective exceeds 40% at 13.5 nm. From the properties of the EUV source (pulse energy 3 mJ at 13.5 nm and plasma diameter approximately 300 {mu}m), energy densities of 73 mJ/cm{sup 2} at a pulse length of 6 ns can be estimated in the image plane of the objective. As a first application, the formation of color centers in lithium fluoride crystals by EUV radiation was investigated. F{sub 2}, F{sub 3}, and F{sub 3}{sup +} color centers could be identified by absorption spectroscopy. The formation dynamics was studied as a function of the EUV dose. By imaging of a pinhole positioned behind the plasma, an EUV spot of 5 {mu}m diameter was generated, which accomplishes direct writing of color centers with micrometer resolution.

  12. From Organized High-Throughput Data to Phenomenological Theory using Machine Learning: The Example of Dielectric Breakdown

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Kim, Chiho; Pilania, Ghanshyam; Ramprasad, Ramamurthy

    2016-02-02

    Understanding the behavior (and failure) of dielectric insulators experiencing extreme electric fields is critical to the operation of present and emerging electrical and electronic devices. Despite its importance, the development of a predictive theory of dielectric breakdown has remained a challenge, owing to the complex multiscale nature of this process. We focus on the intrinsic dielectric breakdown field of insulators—the theoretical limit of breakdown determined purely by the chemistry of the material, i.e., the elements the material is composed of, the atomic-level structure, and the bonding. Starting from a benchmark dataset (generated from laborious first principles computations) of the intrinsicmore » dielectric breakdown field of a variety of model insulators, simple predictive phenomenological models of dielectric breakdown are distilled using advanced statistical or machine learning schemes, revealing key correlations and analytical relationships between the breakdown field and easily accessible material properties. Lastly, the models are shown to be general, and can hence guide the screening and systematic identification of high electric field tolerant materials.« less

  13. PROTON RESONANCE SPECTROSCOPY

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    as a i i . : lJIiaSJ :ShUiI,,:;II. Iii II; PROTON RESONANCE SPECTROSCOPY IN 29p LAWRENCE H. JAMES Triangle Universities Nuclear Laboratory Department of Physics North Carolina State University 1989 - - .. - .. - .. Abstract James, Lawrence Hoy Proton Resonance Spectroscopy in 29 p (Under the direc- tion of Gary E. Mitchell) Proton elastic scattering on 28Si was measured with good beam energy resolution in the proton energy range Ep=1.4 to E =3.75 MeV, and proton inelastic scattering on p 28Si

  14. Synchrotron radiation infrared microscopic study of non-bridging...

    Office of Scientific and Technical Information (OSTI)

    Title: Synchrotron radiation infrared microscopic study of non-bridging oxygen modes associated with laser-induced breakdown of fused silica Authors: Matthews, M J ; Carr, C W ; ...

  15. The {ital T}{sub 1}({ital n}{pi}{asterisk}){l_arrow}{ital S}{sub 0} laser induced phosphorescence excitation spectrum of acetaldehyde in a supersonic free jet: Torsion and wagging potentials in the lowest triplet state

    SciTech Connect (OSTI)

    Liu, H.; Lim, E.C.; Munoz-Caro, C.; Nino, A.; Judge, R.H.; Moule, D.C.

    1996-08-01

    The laser induced {ital T}{sub 1}({ital n}{pi}{asterisk}){l_arrow}{ital S}{sub 0} phosphorescence excitation spectrum of jet-cooled acetaldehyde has been observed for the first time with a rotating slit nozzle excitation system. The vibronic origins were fitted to a set of levels that were obtained from a Hamiltonian that employed flexible torsion-wagging large amplitude coordinates. The potential surface extracted from the fitting procedure yielded barriers to torsion and inversion of 609.68 and 869.02 cm{sup {minus}1}, respectively. Minima in the potential hypersurface at {theta}=61.7{degree} and {alpha}=42.2{degree} defined the equilibrium positions for the torsion and wagging coordinates. A comparison to the corresponding {ital S}{sub 1}-state parameters showed that the torsion barrier (in cm{sup {minus}1}) does not greatly change, {ital S}{sub 1}/{ital T}{sub 1}=710.8/609.7, whereas the barrier height for the wagging-inversion barrier increases dramatically, 574.4/869.0. {copyright} {ital 1996 American Institute of Physics.}

  16. Photoionization Mass Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Photoionization Mass Spectroscopy - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs

  17. Dielectric breakdown properties of hot SF{sub 6}/He mixtures predicted from basic data

    SciTech Connect (OSTI)

    Wang, Weizong; State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an Shaanxi 710049 ; Tu, Xin; Mei, Danhua; Rong, Mingzhe

    2013-11-15

    Sulfur hexafluoride (SF{sub 6}) gas has a quite high global warming potential and hence it is required that applying any substitute for SF{sub 6} gas. Much interest in the use of a mixture of helium and SF{sub 6} as arc quenching medium was investigated indicating a higher recovery performance of arc interruption than that of pure SF{sub 6}. It is known that the electrical breakdown in a circuit breaker after arc interruption occurs in a hot gas environment, with a complicated species composition because of the occurrence of dissociation and other reactions. The likelihood of breakdown relies on the electron interactions with all these species. The critical reduced electric field strength (the field at which breakdown can occur, relative to the number density) of hot SF{sub 6}/He mixtures related to the dielectric recovery phase of a high voltage circuit breaker is calculated in the temperature range from 300 K to 3500 K. The critically reduced electric field strength of these mixtures was obtained by balancing electron generation and loss mechanisms. These were evaluated using the electron energy distribution function derived from the Boltzmann transport equation under the two-term approximation. Good agreement was found between calculations for pure hot SF{sub 6} and pure hot He and experimental results and previous calculations. The addition of He to SF{sub 6} was found to decrease the critical reduced electric field strength in the whole temperature range due to a lack of electron impact attachment process for helium regardless its high ionization potential. This indicates that not the behaviour of dielectric strength but possibly the higher energy dissipation capability caused mainly by light mass and high specific heat as well as thermal conductivity of atomic helium contributes most to a higher dielectric recovery performance of arc interruption for SF{sub 6}/He mixtures.

  18. Breakdown voltage improvement of standard MOS technologies targeted at smart power

    SciTech Connect (OSTI)

    Santos, P.M.; Simas, M.I.C.; Lanca, M.; Finco, S.; Behrens, F.H.

    1995-12-31

    This paper presents and discusses trade-offs of three different design techniques intended to improve the breakdown voltage of n-type lateral medium power transistors to be fabricated in a conventional low cost CMOS technology. A thorough analysis of the static and dynamic characteristics of the modified structures was carried out with the support of a two-dimensional device simulator. The motivation behind this work was the construction of a low cost smart power microsystem, including control, sensing and protection circuitries, targeted at an electronic ballast for efficient control of the power delivered to fluorescent lamps.

  19. SMB, X-ray Absorption Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Absorption Spectroscopy X-ray Absorption Spectroscopy X-ray absorption spectroscopy (XAS) is a well-established technique for simultaneous local geometric and electronic structure...

  20. Al00.3Ga0.7N PN diode with breakdown voltage >1600 V

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Allerman, A. A.; Armstrong, A. M.; Fischer, A. J.; Dickerson, J. R.; Crawford, M. H.; King, M. P.; Moseley, M. W.; Wierer, J. J.; Kaplar, R. J.

    2016-07-21

    Demonstration of Al00.3Ga0.7N PN diodes grown with breakdown voltages in excess of 1600 V is reported. The total epilayer thickness is 9.1 μm and was grown by metal-organic vapour-phase epitaxy on 1.3-mm-thick sapphire in order to achieve crack-free structures. A junction termination edge structure was employed to control the lateral electric fields. A current density of 3.5 kA/cm2 was achieved under DC forward bias and a reverse leakage current <3 nA was measured for voltages <1200 V. The differential on-resistance of 16 mΩ cm2 is limited by the lateral conductivity of the n-type contact layer required by the front-surface contactmore » geometry of the device. An effective critical electric field of 5.9 MV/cm was determined from the epilayer properties and the reverse current–voltage characteristics. To our knowledge, this is the first aluminium gallium nitride (AlGaN)-based PN diode exhibiting a breakdown voltage in excess of 1 kV. Finally, we note that a Baliga figure of merit (Vbr2/Rspec,on) of 150 MW/cm2 found is the highest reported for an AlGaN PN diode and illustrates the potential of larger-bandgap AlGaN alloys for high-voltage devices.« less

  1. Cost and schedule control systems criteria for contract performance measurement: work breakdown structure guide

    SciTech Connect (OSTI)

    Not Available

    1981-10-01

    This document provides guidance on development and use of the Work Breakdown Structure (WBS) technique. It describes the types of work breakdown structures, their preparation, and their effective use for organizing, planning, and controlling projects and contracts managed by the Department of Energy (DOE). The WBS technique is the preferred management tool for identifying and defining work. It provides an ordered framework for planning and controlling the work efforts to be performed in achieving technical objectives and for summarizing data, and the quantitative and narrative reports used for monitoring cost, schedule and technical performance. A WBS is developed for first identifying the major end items or systems to be produced, followed by their successive subdivision into increasingly detailed and manageable subsidiary products. Most of these subsidiary products are the direct result of work, while others are simply the aggregation of selected products into a logical set for management control purposes. In either case, detailed tasks are eventually identified for each product on the WBS at the level where work will be performed. As a minimum, these detailed tasks or work packages identify the product, describe the effort to be performed, identify the resources to be applied, specify the budget and schedule constraints, and the technical requirements, and identify the organizational element responsible for work accomplishment.

  2. INVESTIGATION OF BREAKDOWN INDUCED SURFACE DAMAGE ON 805 MHZ PILLBOX CAVITY INTERIOR SURFACES

    SciTech Connect (OSTI)

    Jana, M. R.; Chung, M.; Leonova, M.; Moretti, A.; Tollestrup, A.; Yonehara, K.; Freemire, B.; Torun, Y.; Bowring, D.; Flanagan, G.

    2013-09-25

    The MuCool Test Area (MTA) at Fermilab is a facility to develop the technology required for ionization cooling for a future Muon Collider and/or Neutrino Factory. As part of this research program, we have tested two 805 MHz vacuum RF cavities in a multi-Tesla magnetic field to study the effects of the static magnetic field on the cavity operation. This study gives useful information on field emitters in the cavity, dark current, surface conditioning, breakdown mechanisms and material properties of the cavity. All these factors determine the maximum accelerating gradient in the cavity. This paper discusses the image processing technique for quantitative estimation of spark damage spot distribution on cavity interior surfaces. The distribution is compared with the electric field distribution predicted by a computer code calculation. The local spark density is proportional to probability of surface breakdown and shows a power law dependence on the maximum electric field (E). This E dependence is consistent with the dark current calculated from the Fowler-Nordheim equation.

  3. Gas breakdown mechanism in pulse-modulated asymmetric ratio frequency dielectric barrier discharges

    SciTech Connect (OSTI)

    Wang, Qi; Sun, Jizhong, E-mail: jsun@dlut.edu.cn; Ding, Zhenfeng; Ding, Hongbin; Wang, Dezhen [School of Physics and Optoelectronic Engineering, Dalian University of Technology, Dalian 116023 (China); Nozaki, Tomohiro [Department of Mechanical Sciences and Engineering, Tokyo Institute of Technology, Tokyo 152-8550 (Japan); Wang, Zhanhui [Southwestern Institute of Physics, Chengdu 610041 (China)

    2014-08-15

    The gas breakdown mechanisms, especially the roles of metastable species in atmospheric pressure pulse-modulated ratio frequency barrier discharges with co-axial cylindrical electrodes, were studied numerically using a one dimensional self-consistent fluid model. Simulation results showed that in low duty cycle cases, the electrons generated from the channels associated with metastable species played a more important role in initializing next breakdown than the direct ionization of helium atoms of electronic grounded states by electron-impact. In order to quantitatively evaluate the contribution to the discharge by the metastables, we defined a characteristic time and examined how the value varied with the gap distance and the electrode asymmetry. The results indicated that the lifetime of the metastable species (including He*and He{sub 2}{sup *}) was much longer than that of the pulse-on period and as effective sources of producing electrons they lasted over a period up to millisecond. When the ratio of the outer radius to the inner radius of the cylindrical electrodes was far bigger than one, it was found that the metastables distributed mainly in a cylindrical region around the inner electrode. When the ratio decreased as the inner electrode moved outward, the density of metastables in the discharge region near the outer electrode became gradually noticeable. As the discharging gap continued to decrease, the two hill-shaped distributions gradually merged to one big hill. When the discharge spacing was fixed, asymmetric electrodes facilitated the discharge.

  4. Spectrographic temperature measurement of a high power breakdown arc in a high pressure gas switch

    SciTech Connect (OSTI)

    Yeckel, Christopher; Curry, Randy

    2011-09-15

    A procedure for obtaining an approximate temperature value of conducting plasma generated during self-break closure of a RIMFIRE gas switch is described. The plasma is in the form of a breakdown arc which conducts approximately 12 kJ of energy in 1 {mu}s. A spectrographic analysis of the trigger-section of the 6-MV RIMFIRE laser triggered gas switch used in Sandia National Laboratory's ''Z-Machine'' has been made. It is assumed that the breakdown plasma has sufficiently approached local thermodynamic equilibrium allowing a black-body temperature model to be applied. This model allows the plasma temperature and radiated power to be approximated. The gas dielectric used in these tests was pressurized SF{sub 6}. The electrode gap is set at 4.59 cm for each test. The electrode material is stainless steel and insulator material is poly(methyl methacrylate). A spectrum range from 220 to 550 nanometers has been observed and calibrated using two spectral irradiance lamps and three spectrograph gratings. The approximate plasma temperature is reported.

  5. Nonlinear Laser Spectroscopy

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Laser Spectroscopy - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power Supercritical CO2 Geothermal Natural Gas Safety, Security & Resilience of the Energy Infrastructure Energy Storage Nuclear Power & Engineering Grid Modernization Battery Testing Nuclear Energy Defense Waste Management Programs Advanced Nuclear

  6. Calculation of the spatial resolution in two-photon absorption spectroscopy applied to plasma diagnosis

    SciTech Connect (OSTI)

    Garcia-Lechuga, M.; Fuentes, L. M.; Grützmacher, K.; Pérez, C. Rosa, M. I. de la

    2014-10-07

    We report a detailed characterization of the spatial resolution provided by two-photon absorption spectroscopy suited for plasma diagnosis via the 1S-2S transition of atomic hydrogen for optogalvanic detection and laser induced fluorescence (LIF). A precise knowledge of the spatial resolution is crucial for a correct interpretation of measurements, if the plasma parameters to be analysed undergo strong spatial variations. The present study is based on a novel approach which provides a reliable and realistic determination of the spatial resolution. Measured irradiance distribution of laser beam waists in the overlap volume, provided by a high resolution UV camera, are employed to resolve coupled rate equations accounting for two-photon excitation, fluorescence decay and ionization. The resulting three-dimensional yield distributions reveal in detail the spatial resolution for optogalvanic and LIF detection and related saturation due to depletion. Two-photon absorption profiles broader than the Fourier transform-limited laser bandwidth are also incorporated in the calculations. The approach allows an accurate analysis of the spatial resolution present in recent and future measurements.

  7. (Resonance ionization spectroscopy)

    SciTech Connect (OSTI)

    Young, J.P.

    1990-10-11

    J. P. Young attended the Fifth International Symposium on Resonance Ionization Spectroscopy and presented an invited oral presentation on research he and coworkers had carried out in applying diode lasers to resonance ionization mass spectrometry. A summary of the conference is given along with an assessment of some of the presentations that the author found of interest. Young also visited Professor Marassi at the University of Camerino to present a seminar and discuss mutual interests in a new molten salt research project of the author. Some of the studies at Camerino are described. Ideas concerning the author's research that came from private discussions are also presented here.

  8. Two-phase mixed media dielectric with macro dielectric beads for enhancing resistivity and breakdown strength

    DOE Patents [OSTI]

    Falabella, Steven; Meyer, Glenn A; Tang, Vincent; Guethlein, Gary

    2014-06-10

    A two-phase mixed media insulator having a dielectric fluid filling the interstices between macro-sized dielectric beads packed into a confined volume, so that the packed dielectric beads inhibit electro-hydrodynamically driven current flows of the dielectric liquid and thereby increase the resistivity and breakdown strength of the two-phase insulator over the dielectric liquid alone. In addition, an electrical apparatus incorporates the two-phase mixed media insulator to insulate between electrical components of different electrical potentials. And a method of electrically insulating between electrical components of different electrical potentials fills a confined volume between the electrical components with the two-phase dielectric composite, so that the macro dielectric beads are packed in the confined volume and interstices formed between the macro dielectric beads are filled with the dielectric liquid.

  9. Nonlinear theory of drift-cyclotron kinetics and the possible breakdown of gyro-kinetics

    SciTech Connect (OSTI)

    Waltz, R. E.; Deng Zhao

    2013-01-15

    A nonlinear theory of drift-cyclotron kinetics (termed cyclo-kinetics here) is formulated to test the breakdown of the gyro-kinetic approximations. Six dimensional cyclo-kinetics can be regarded as an extension of five dimensional gyro-kinetics to include high-frequency cyclotron waves, which can interrupt the low-frequency gyro-averaging in the (sixth velocity grid) gyro-phase angle. Nonlinear cyclo-kinetics has no limit on the amplitude of the perturbations. Formally, there is no gyro-averaging when all cyclotron (gyro-phase angle) harmonics of the perturbed distribution function (delta-f) are retained. Retaining only the (low frequency) zeroth cyclotron harmonic in cyclo-kinetics recovers both linear and nonlinear gyro-kinetics. Simple recipes are given for converting continuum nonlinear delta-f gyro-kinetic transport simulation codes to cyclo-kinetics codes by retaining (at least some) higher cyclotron harmonics.

  10. Corrosion potential and breakdown potential distributions for stainless steels in seawater

    SciTech Connect (OSTI)

    Salvago, G.; Fumagalli, G.; Taccani, G.

    1996-10-01

    The definition of corrosion potential was examined in relation to stainless steels in seawater. The experimental investigation was extended to include austenitic, ferritic and superaustenitic stainless steels. From each material, between 30 and 100 specimens were taken for a total of over 1,000. Measurements of the corrosion potentials of specimens of different sizes and under different exposure conditions were carried out as well as those of the breakdown potentials in cells that could contain up to 100 specimens and also measurements on galvanic couples. All the tests were performed with natural seawater in experiments lasting over a period from 1 to 18 months. The results obtained have shown that: The corrosion potentials of stainless steel in seawater are dispersed in a wide range; The dispersion is not only attributable to fluctuations of the environmental characteristics or to differences between the specimens of the same steel but is an intrinsic characteristic of the specific corrosion system; The distribution of the corrosion potentials measured on the same specimen at different times is similar to the distribution of the corrosion potentials of different specimens, of the same sample, measured at the same time. The distribution of corrosion potentials, like the distribution of breakdown potentials, is affected by the size of the specimens, the exposure conditions and whether forms of localized corrosions are present. A peculiar role in the corrosion potential distribution appears to be played by the galvanic coupling between the surface of the stainless steel and predetermined non-uniform areas such as the edges of the specimens or not predetermined like the areas of development of the localized attack or fluctuating in space and time like the areas of potential or incipient attack.