National Library of Energy BETA

Sample records for laser-induced breakdown spectroscopy

  1. Laser-Induced Breakdown Spectroscopy

    E-Print Network [OSTI]

    Nizkorodov, Sergey

    LIBS-1 Laser-Induced Breakdown Spectroscopy LIBS ANALYSIS OF METAL SURFACES Last updated: June 17, 2014 #12;LIBS-2 Laser­Induced Breakdown Spectroscopy (LIBS) LIBS ANALYSIS OF METAL SURFACES of species at a distance or in hard­to­reach or hazardous environments. Laser­Induced Breakdown Spectroscopy

  2. Methods for measurement of heterogeneous materials with laser-induced breakdown spectroscopy (LIBS)

    E-Print Network [OSTI]

    Effenberger, Andrew Jay

    2009-01-01

    pulse laser-induced breakdown spectroscopy ICCD – intensified charge-coupled device LSC – laser-supported combustion

  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. Trace metal mapping by laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Kaiser, Jozef [ORNL; Novotny, Dr. Karel [Masaryk University; Hrdlicka, A [Brno University of Technology, Czech Republic; Malina, R [Brno University of Technology, Czech Republic; Hartl, M [Brno University of Technology, Czech Republic; Kizek, R [Mendel University of Brno; Adam, V [Mendel University of Brno

    2012-01-01

    Abstract: Laser-Induced Breakdown Spectroscopy (LIBS) is a sensitive optical technique capable of fast multi-elemental analysis of solid, gaseous and liquid samples. The potential applications of lasers for spectrochemical analysis were developed shortly after its invention; however the massive development of LIBS is connected with the availability of powerful pulsed laser sources. Since the late 80s of 20th century LIBS dominated the analytical atomic spectroscopy scene and its application are developed continuously. Here we review the utilization of LIBS for trace elements mapping in different matrices. The main emphasis is on trace metal mapping in biological samples.

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

    DOE Patents [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.

  6. 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.

  7. Enhancing the analytical performance of laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Cremers, D.A.; Chinni, R.C.; Pichahchy, A.E.; Thornquist, H.K.

    1998-12-31

    This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The objective of this work is to enhance the analytical capabilities of laser-induced breakdown spectroscopy (LIBS). LIBS is a method of elemental analysis in which powerful laser pulses are focused on a sample to form a microplasma. LIBS is perhaps the most versatile elemental analysis method, applicable to a variety of different real-world analysis problems. Therefore, it is important to enhance the capabilities of the method as much as possible. Accomplishments include: (1) demonstration of signal enhancements of 5--30 times from soils and metals using a double pulse method; (2) development of a model of the observed enhancement obtained using double pulses; (3) demonstration that the analytical performance achievable using low laser-pulse energies (10 and 25 mJ) can match that achievable using an energy of 100 mJ; and (4) demonstration that time-gated detection is not necessary with LIBS.

  8. Procedure for calibration of a portable, real-time beryllium aerosol monitor based on laser-induced breakdown spectroscopy 

    E-Print Network [OSTI]

    Killough, David Thomas

    2000-01-01

    7300, "Elements by ICP." The most objectionable disadvantage to NIOSH Method 7300 is that a waiting period of approximately 8 hours is required to obtain results. Laser-induced Breakdown Spectroscopy (LIBS), sometimes called Laser-induced Plasma...

  9. 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.

  10. 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.

  11. Particle size limits for quantitative aerosol analysis using laser-induced breakdown spectroscopy: Temporal considerations

    E-Print Network [OSTI]

    Hahn, David W.

    dissociation, vaporization and linear analyte response of an individual particle suspended in a gas stream individual silica microspheres in an aerosolized air stream was investigated using laser-induced breakdown of analyte signals for the 2.47 and 4.09-micrometer particles was observed to be approximately constant

  12. Determination of elemental impurities in plastic calibration standards using laser induced breakdown spectroscopy

    SciTech Connect (OSTI)

    McIntyre, D.; Ayyalasomayajula, K.; Jain, J.; Singh, J.; Yu-Yueh, F.

    2012-01-01

    Dual-energy computed tomography (CT) scanning is a rapidly emerging imaging technique employed in nondestructive evaluation of various materials. CT has been used for characterizing rocks and visualizing multiphase flow through rocks for over 25 years. The most common technique for dual-energy CT scanning relies on homogeneous calibration standards to produce the most accurate decoupled data. However, the use of calibration standards with impurities increases the probability of error in the reconstructed data and results in poor rock characterization. Laser-induced breakdown spectroscopy was used to determine impurity concentration in a set of commercially purchased calibration standards used in dual-energy scanning for material identification with coal samples. Two calibration models were developed by using univariate calibration with the internal ratio method and multiple linear regression. Seven elements (Al, Fe, Mg, Na, Ni, Sr, and Ti) were examined in five different samples containing varying amounts of each ion to compare calibration from univariate data analysis and from multivariate data analysis. The contaminant concentrations were also measured by a commercially available inductively coupled plasma optical emission spectroscopy instrument, and the data were used as a reference in developing calibration curves for a modified version of the single linear regression model and the multiple linear regression model.

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

    SciTech Connect (OSTI)

    Shaw, G., E-mail: shawgc@ornl.gov [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States); University of Tennessee, Knoxville, Tennessee 37996 (United States); Martin, M. Z.; Martin, R.; Biewer, T. M. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830 (United States)

    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.

  14. 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.

  15. 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.

  16. High repetition rate laser-induced breakdown spectroscopy using acousto-optically gated detection

    SciTech Connect (OSTI)

    Po?ízka, Pavel [BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Straße 11, D-12489 Berlin (Germany); Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 61669 Brno (Czech Republic); Klessen, Benjamin; Gornushkin, Igor; Riedel, Jens [BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Straße 11, D-12489 Berlin (Germany); Kaiser, Jozef [Institute of Physical Engineering, Faculty of Mechanical Engineering, Brno University of Technology, Technicka 2896/2, 61669 Brno (Czech Republic); Panne, Ulrich [BAM Federal Institute for Materials Research and Testing, Richard-Willstätter-Straße 11, D-12489 Berlin (Germany); Chemistry Department, Humboldt Universität zu Berlin, Brook-Taylor-Straße 2, D-12489 Berlin (Germany)

    2014-07-15

    This contribution introduces a new type of setup for fast sample analysis using laser-induced breakdown spectroscopy (LIBS). The novel design combines a high repetition rate laser (up to 50 kHz) as excitation source and an acousto-optical modulator (AOM) as a fast switch for temporally gating the detection of the emitted light. The plasma radiation is led through the active medium of the AOM where it is diffracted on the transient ultrasonic Bragg grid. The diffracted radiation is detected by a compact Czerny-Turner spectrometer equipped with a CCD line detector. Utilizing the new combination of high repetition rate lasers and AOM gated detection, rapid measurements with total integration times of only 10 ms resulted in a limit of detection (LOD) of 0.13 wt.% for magnesium in aluminum alloys. This short integration time corresponds to 100 analyses/s. Temporal gating of LIP radiation results in improved LODs and consecutively higher sensitivity of the LIBS setup. Therefore, an AOM could be beneficially utilized to temporally detect plasmas induced by high repetition rate lasers. The AOM in combination with miniaturized Czerny-Turner spectrometers equipped with CCD line detectors and small footprint diode pumped solid state lasers results in temporally gateable compact LIBS setups.

  17. 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.

  18. Effect of atmosphere on collinear double-pulse laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

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

    2010-09-01

    Double pulse laser induced breakdown spectroscopy (DP-LIBS) has been shown to enhance LIBS spectra. Several researches have reported significant increases in signal-to-noise and or spectral intensity [1-4]. In addition to DP-LIBS, atmospheric conditions can also increase spectra intensity. For example, Iida [5] found that He and Ar both increase LIBS intensity compared to air at one 1 atm. It was also found that as the pressure was decreased to 100 Torr, LIBS intensity increased in Ar and air for single pulse (SP) LIBS. In this study, a collinear DP-LIBS scheme is used along with manipulation of the atmospheric conditions. The DP-LIBS scheme consists of a 355 nm ablative pulse fired into a sample contained in a vacuum chamber. A second analytical 1064 nm pulse is then fired 100 ns to 10 µs after and along the same path of the first pulse. Ar, He and air at pressures ranging from atmospheric pressure (630 Torr at elevation) to 10-5 Torr are introduced during DP-LIBS and SP-LIBS experiments. For a brass sample, a significant increase in spectral intensity of Cu and Zn lines were observed in DP-LIBS under Ar compared to DP-LIBS in air (Figure 1). It was also found that Cu and Zn lines acquired with SP-LIBS in Ar are nearly as intense as DP-LIBS in air. Signal-to-noise for lines from various samples will be reported for both DP-LIBS and SP-LIBS in Ar, He, and air at pressures ranging from 630 Torr to 10-5 Torr.

  19. 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 quantitatively determine the major elemental abundance of the remaining samples. PLS analysis suggests that the major element compositions can be determined with root mean square errors ca. 5% (absolute) for SiO{sub 2}, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}(total), MgO, and CaO, and ca. 2% or less for TiO{sub 2}, Cr{sub 2}O{sub 3}, MnO, K{sub 2}O, and Na{sub 2}O. Finally, the Raman experiments have been conducted under supercritical CO{sub 2} involving single-mineral and mixed-mineral samples containing talc, olivine, pyroxenes, feldspars, anhydrite, barite, and siderite. The Raman data have shown that the individual minerals can easily be identified individually or in mixtures.

  20. Electron-ion relaxation time dependent signal enhancement in ultrafast double-pulse laser-induced breakdown spectroscopy

    SciTech Connect (OSTI)

    Harilal, S. S.; Diwakar, P. K.; Hassanein, A. [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)] [Center for Materials Under Extreme Environment, School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

    2013-07-22

    We investigated the emission properties of collinear double-pulse compared to single-pulse ultrafast laser induced breakdown spectroscopy. Our results showed that the significant signal enhancement noticed in the double pulse scheme is strongly correlated to the characteristic electron-ion relaxation time and hence to the inter-pulse delays. Spectroscopic excitation temperature analysis showed that the improvement in signal enhancement is caused by the delayed pulse efficient reheating of the pre-plume. The signal enhancement is also found to be related to the upper excitation energy of the selected lines, i.e., more enhancement noticed for lines originating from higher excitation energy levels, indicating reheating is the major mechanism behind the signal improvement.

  1. 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.

  2. 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 1.7×10{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.

  3. 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.

  4. Design of a laser-induced breakdown spectroscopy system for on-line quality analysis of pulverized coal in power plants

    SciTech Connect (OSTI)

    Yin, W.B.; Zhang, L.; Dong, L.; Ma, W.G.; Jia, S.T. [Shanxi Agricultural University, Taiyuan (China)

    2009-08-15

    It is vitally important for a power plant to determine the chemical composition of coal prior to combustion in order to obtain optimal boiler control. In this work, a fully software-controlled laser-induced breakdown spectroscopy (LIBS) system comprising a LIBS apparatus and sampling equipment has been designed for possible application to power plants for on-line quality analysis of pulverized coal. Special attention was given to the LIBS system, the data processing methods (especially the normalization with Bode Rule/DC Level) and the specific settings (the software-controlled triggering source, high-pressure gas cleaning device, sample preparation module, sampling module, etc.), which gave the best direct measurement for C, H, Si, Na, Mg, Fe, Al, and Ti with measurement errors less than 10% for pulverized coal. Therefore, the apparatus is accurate enough to be applied to industries for on-line monitoring of pulverized coal. The method of proximate analysis was also introduced and the experimental error of A(ad) (Ash, 'ad' is an abbreviation for 'air dried') was shown in the range of 2.29 to 13.47%. The programmable logic controller (PLC) controlled on-line coal sampling equipment, which is designed based upon aerodynamics, and is capable of performing multipoint sampling and sample-preparation operation.

  5. 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 nor lab-based spectroscopy yielded even semi-quantitative SOC predictions. There was little SOC variability to explain across the eight fields, and on-the-go VisNIR was not able to capture the subtle SOC variability in these Montana soils. With more variation in soil clay content compared to SOC, both lab and on-the-go VisNIR showed better explanatory power. There are several potential explanations for poor on-the-go predictive accuracy: soil heterogeneity, field moisture, consistent sample presentation, and a difference between the spatial support of on-the-go measurements and soil samples collected for laboratory analyses. Though the current configuration of a commercially available on-the-go VisNIR system allows for rapid field scanning, on-the-go soil processing (i.e. drying, crushing, and sieving) could improve soil carbon predictions. Laser-induced breakdown spectroscopy (LIBS) is an emerging elemental analysis technology with the potential to provide rapid, accurate and precise analysis of soil constituents, such as carbon, in situ across landscapes. The research team evaluated the accuracy of LIBS for measuring soil profile carbon in field-moist, intact soil cores simulating conditions that might be encountered by a probe-mounted LIBS instrument measuring soil profile carbon in situ. Over the course of three experiments, more than120 intact soil cores from eight north central Montana wheat fields and the Washington State University (WSU) Cook Agronomy Farm near Pullman, WA were interrogated with LIBS for rapid total carbon (TC), inorganic carbon (IC), and SOC determination. Partial least squares regression models were derived and independently validated at field- and regional scales. Researchers obtained the best LIBS validation predictions for IC followed by TC and SOC. Laser-induced breakdown spectroscopy is fundamentally an elemental analysis technique, yet LIBS PLS2 models appeared to discriminate IC from TC. Regression coefficients from initial models suggested a reliance upon stoichiometric relationships between carbon (247.8 nm) and other elements

  6. Bulk measurement of copper and sodium content in CuIn(0.7)Ga(0.3)Se(2) (CIGS) solar cells with nanosecond pulse length laser induced breakdown spectroscopy (LIBS)

    E-Print Network [OSTI]

    Kowalczyk, Jeremy M D; DeAngelis, Alexander; Kaneshiro, Jess; Mallory, Stewart A; Chang, Yuancheng; Gaillard, Nicolas

    2013-01-01

    In this work, we show that laser induced breakdown spectroscopy (LIBS) with a nanosecond pulse laser can be used to measure the copper and sodium content of CuIn(0.7)Ga(0.3)Se(2) (CIGS) thin film solar cells on molybdenum. This method has four significant advantages over methods currently being employed: the method is inexpensive, measurements can be taken in times on the order of one second, without high vacuum, and at distances up to 5 meters or more. The final two points allow for in-line monitoring of device fabrication in laboratory or industrial environments. Specifically, we report a linear relationship between the copper and sodium spectral lines from LIBS and the atomic fraction of copper and sodium measured via secondary ion mass spectroscopy (SIMS), discuss the ablation process of this material with a nanosecond pulse laser compared to shorter pulse duration lasers, and examine the depth resolution of nanosecond pulse LIBS.

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

    SciTech Connect (OSTI)

    Rohlfing, E.A. [Sandia National Laboratories, Livermore, CA (United States)

    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.

  8. Characterization of hydrocarbon and mixed layers in TEXTOR by laser induced ablation spectroscopy

    E-Print Network [OSTI]

    Giesen, Thomas

    Characterization of hydrocarbon and mixed layers in TEXTOR by laser induced ablation spectroscopy) 014026 (4pp) doi:10.1088/0031-8949/2011/T145/014026 Characterization of hydrocarbon and mixed layers systematic laser-induced ablation spectroscopy (LIAS) measurements carried out on various surface layers

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

    DOE Patents [OSTI]

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

    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.

  10. Laser Induced Breakdown Spectroscopy and Applications Toward Thin Film Analysis

    E-Print Network [OSTI]

    Owens, Travis Nathan

    2011-01-01

    solar cells In recent years the focus on energy research has gained more popularity and much more funding,

  11. Aerosol measurements with laser-induced breakdown spectroscopy

    E-Print Network [OSTI]

    Lithgow, Gregg Arthur

    2007-01-01

    Emission Spectrometry. Analytical Chemistry, vol. 40, no. 5,an aluminum alloy. Analytical Chemistry, vol. 41, no. 6, p.TrAC-Trends in Analytical Chemistry, vol. 17, no. 6, p. 328,

  12. Laser Induced Breakdown Spectroscopy and Applications Toward Thin Film Analysis

    E-Print Network [OSTI]

    Owens, Travis Nathan

    2011-01-01

    1.5 Laserb) 60 shots, (c) 80 shots, and (d) 100 shots with 60mJ laserAutofocusing . . . . . . . . . . 2.4 Laser and Spectrometer

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

    Office of Scientific and Technical Information (OSTI)

    20853313 Resource Type: Journal Article Resource Relation: Journal Name: Applied Optics; Journal Volume: 45; Journal Issue: 18; Other Information: DOI: 10.1364AO.45.004411;...

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

    Office of Scientific and Technical Information (OSTI)

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

  15. Laser Induced Breakdown Spectroscopy and Applications Toward Thin Film Analysis

    E-Print Network [OSTI]

    Owens, Travis Nathan

    2011-01-01

    of CIGS solar cells . Conclusions . . . . . . . . . . . . .roll-to-roll printed CIGS solar cell on aluminum substrateDepth profiling of CIGS solar cell using a nanosecond Nd:YAG

  16. Laser Induced Breakdown Spectroscopy and Applications Toward Thin Film Analysis

    E-Print Network [OSTI]

    Owens, Travis Nathan

    2011-01-01

    Organic Thin Films 4.1 Introduction . . . . . . . . . . . .T iO 2 thin films. . . . . . . . . . . . . . . . . . . . .properties of the organic thin films. . . . . . . . .

  17. Laser-induced breakdown spectroscopy at high temperatures in industrial

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journalspectroscopy of aerosols(TechnicalConnectpulse in gas-filled hohlraums

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACT EVALUATION PLAN FOR THE SITE-218 58 84 168 167Control -

  19. 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.

  20. Modeling the effect of native and laser-induced states on the dielectric breakdown of wide band gap optical materials by multiple subpicosecond laser pulses

    SciTech Connect (OSTI)

    Emmert, Luke A.; Mero, Mark; Rudolph, Wolfgang [Department of Physics and Astronomy, University of New Mexico, Albuquerque, New Mexico 87131 (United States)

    2010-08-15

    A model for the multiple-pulse laser-induced breakdown behavior of dielectrics is presented. It is based on a critical conduction band (CB) electron density leading to dielectric breakdown. The evolution of the CB electron density during the pulse train is calculated using rate equations involving transitions between band and mid-gap states (native and laser-induced). Using realistic estimations for the trap density and ionization cross-section, the model is able to reproduce the experimentally observed drop in the multiple-pulse damage threshold relative to the single-pulse value, as long as the CB electron density is controlled primarily by avalanche ionization seeded by multiphoton ionization of the traps and the valence band. The model shows that at long pulse duration, the breakdown threshold becomes more sensitive to presence of traps close (within one photon energy) to the CB. The effect of native and laser-induced defects can be distinguished by their saturation behavior. Finally, measurements of the multiple-pulse damage threshold of hafnium oxide films are used to illustrate the application of the model.

  1. Single Variable and Multivariate Analysis of Remote Laser-Induced Breakdown Spectra for Prediction of Rb, Sr, Cr, Ba, and V in Igneous Rocks

    SciTech Connect (OSTI)

    Clegg, Samuel M [Los Alamos National Laboratory; Wiens, Roger C. [Los Alamos National Laboratory; Speicher, Elly A [MT HOLYOKE COLLEGE; Dyar, Melinda D [MT HOLYOKE COLLEGE; Carmosino, Marco L [MT HOLYOKE COLLEGE

    2010-12-23

    Laser-induced breakdown spectroscopy (LIBS) will be employed by the ChemCam instrument on the Mars Science Laboratory rover Curiosity to obtain UV, VIS, and VNIR atomic emission spectra of surface rocks and soils. LIBS quantitative analysis is complicated by chemical matrix effects related to abundances of neutral and ionized species in the resultant plasma, collisional interactions within plasma, laser-to-sample coupling efficiency, and self-absorption. Atmospheric composition and pressure also influence the intensity of LIBS plasma. These chemical matrix effects influence the ratio of intensity or area of a given emission line to the abundance of the element producing that line. To compensate for these complications, multivariate techniques, specifically partial least-squares regression (PLS), have been utilized to predict major element compositions (>1 wt.% oxide) of rocks, PLS methods regress one or multiple response variables (elemental concentrations) against multiple explanatory variables (intensity at each pixel of the spectrometers). Because PLS utilizes all available explanatory variable and eliminates multicollinearity, it generally performs better than univariate methods for prediction of major elements. However, peaks arising from emissions from trace elements may be masked by peaks of higher intensities from major elements. Thus in PLS regression, wherein a correlation coefficient is determined for each elemental concentration at each spectrometer pixel, trace elements may show high correlation with more intense lines resulting from optical emissions of other elements. This could result in error in predictions of trace element concentrations. Here, results of simple linear regression (SLR) and multivariate PLS-2 regression for determination of trace Rb, Sr, Cr, Ba, and V in igneous rock samples are compared. This study focuses on comparisons using only line intensities rather than peak areas to highlight differences between SLR and PLS.

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

    SciTech Connect (OSTI)

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

    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.

  3. Spectroscopic characterization of laser-induced tin plasma S. S. Harilal,a

    E-Print Network [OSTI]

    Harilal, S. S.

    using singly ionized Sn lines, while density measurements were made using the Stark broadening method deposition,5 nanoparticle and cluster production,6,7 and laser-induced breakdown spectroscopy LIBS .8 Laser setup very simple and adaptable to automation and remote sensing. Using OES one can obtain fundamental

  4. Methods for measurement of heterogeneous materials with laser-induced breakdown spectroscopy (LIBS)

    E-Print Network [OSTI]

    Effenberger, Andrew Jay

    2009-01-01

    a fiber-optic probe. Analytical Chemistry, vol. 68, p. 977,Fresenius Journal Analytical Chemistry, vol. 355, p.10,ablation of brass. Analytical Chemistry, vol. 77, p. 6687,

  5. Calibration Effects for Laser-Induced Breakdown Spectroscopy of Gaseous Sample Streams

    E-Print Network [OSTI]

    Hahn, David W.

    when nebulizing either lead acetate, lead chloride, or lead nitrate. Cadmium revealed a 27% difference in analyte response when comparing nebulized solutions of cadmium nitrate and cadmium chloride. In experi.19 Calibration curves were generated for three analytes, namely, cadmium, lead, and zinc, and were

  6. Methods for measurement of heterogeneous materials with laser-induced breakdown spectroscopy (LIBS)

    E-Print Network [OSTI]

    Effenberger, Andrew Jay

    2009-01-01

    Electrorefiners are used to reprocess nuclear fuel forElectrorefiners are used to reprocess nuclear fuel for

  7. Methods for measurement of heterogeneous materials with laser-induced breakdown spectroscopy (LIBS)

    E-Print Network [OSTI]

    Effenberger, Andrew Jay

    2009-01-01

    as in spent fuel reprocessing. The lead-glass shieldcurrently involved in the reprocessing of nuclear materialintegral piece of this reprocessing is an electrorefiner. A

  8. Laser-induced breakdown spectroscopy of alkali metals in high-temperature

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journalspectroscopy of aerosols(TechnicalConnectpulse in gas-filled hohlraumsgas

  9. 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 [Technische Universitaet Braunschweig, Institut fuer Physikalische und Theoretische Chemie Hans-Sommer-Str. 10, 38106 Braunschweig (Germany)

    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.

  10. 26 SpectrosiopY 24(9} September 2009 www.spectroscopyonlinc.com Laser-Induced Breakdown Spectroscopy

    E-Print Network [OSTI]

    Hahn, David W.

    calibration curves for three analytes -- namely cadmium, lead, and zinc -- which were characterized by initial acetate, lead chloride, or lead nitrate. In addition to analysis of particle-derived analyte signals

  11. 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.

  12. Laboratory evaluation of laser-induced breakdown spectroscopy (LIBS) as a new in situ chemical sensing technique for the deep ocean

    E-Print Network [OSTI]

    Michel, Anna Pauline Miranda, 1976-

    2007-01-01

    Present-day expeditionary oceanography is beginning to shift from a focus on short-term ship and submersible deployments to an ocean observatory mode where long-term temporally-focused studies are feasible. As a result, a ...

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

    Office of Scientific and Technical Information (OSTI)

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

  14. 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.

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

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journalspectroscopy of aerosols in high-temperature applications. (Journal Article) |

  16. Laser Induced Spectroscopy - Energy Innovation Portal

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousand CubicResourcelogo and- Energy Innovation Portal

  17. Quantitative Depth Profiling of Biporous Nickel Electrodes by Frequency-Domain Laser-Induced

    E-Print Network [OSTI]

    Mandelis, Andreas

    for the long-term stability and high efficiency of electrochemical energy conversion in fuel cells manufactured for use in electrochemical energy conversion de- vices, such as fuel cells. Index Headings: Laser-induced photoacoustic spectroscopy; Variable electrode porosities; Frequency response; Quantitative analysis; Fuel cells

  18. Ultraviolet versus infrared: Effects of ablation laser wavelength on the expansion of laser-induced plasma into one-atmosphere argon gas

    SciTech Connect (OSTI)

    Ma Qianli; Motto-Ros, Vincent; Laye, Fabrice; Yu Jin [Universite de Lyon, F-69622, Lyon, France, Universite Lyon 1, Villeurbanne, CNRS, UMR5579, LASIM (France); Lei Wenqi; Bai Xueshi; Zheng Lijuan; Zeng Heping [State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai (China)

    2012-03-01

    Laser-induced plasma from an aluminum target in one-atmosphere argon background has been investigated with ablation using nanosecond ultraviolet (UV: 355 nm) or infrared (IR: 1064 nm) laser pulses. Time- and space-resolved emission spectroscopy was used as a diagnostics tool to have access to the plasma parameters during its propagation into the background, such as optical emission intensity, electron density, and temperature. The specific feature of nanosecond laser ablation is that the pulse duration is significantly longer than the initiation time of the plasma. Laser-supported absorption wave due to post-ablation absorption of the laser radiation by the vapor plume and the shocked background gas plays a dominant role in the propagation and subsequently the behavior of the plasma. We demonstrate that the difference in absorption rate between UV and IR radiations leads to different propagation behaviors of the plasma produced with these radiations. The consequence is that higher electron density and temperature are observed for UV ablation. While for IR ablation, the plasma is found with lower electron density and temperature in a larger and more homogenous axial profile. The difference is also that for UV ablation, the background gas is principally evacuated by the expansion of the vapor plume as predicted by the standard piston model. While for IR ablation, the background gas is effectively mixed to the ejected vapor at least hundreds of nanoseconds after the initiation of the plasma. Our observations suggest a description by laser-supported combustion wave for the propagation of the plasma produced by UV laser, while that by laser-supported detonation wave for the propagation of the plasma produced by IR laser. Finally, practical consequences of specific expansion behavior for UV or IR ablation are discussed in terms of analytical performance promised by corresponding plasmas for application with laser-induced breakdown spectroscopy.

  19. Quantitative planar laser-induced fluorescence imaging of multi...

    Office of Scientific and Technical Information (OSTI)

    Article: Quantitative planar laser-induced fluorescence imaging of multi-component fuelair mixing in a firing gasoline-direct-injection engine: Effects of residual exhaust...

  20. Modeling of Laser-Induced Metal Combustion

    SciTech Connect (OSTI)

    Boley, C D; Rubenchik, A M

    2008-02-20

    Experiments involving the interaction of a high-power laser beam with metal targets demonstrate that combustion plays an important role. This process depends on reactions within an oxide layer, together with oxygenation and removal of this layer by the wind. We present an analytical model of laser-induced combustion. The model predicts the threshold for initiation of combustion, the growth of the combustion layer with time, and the threshold for self-supported combustion. Solutions are compared with detailed numerical modeling as benchmarked by laboratory experiments.

  1. Laser Induced Molecular Spectroscopy of Zn{sub 2} Molecule

    SciTech Connect (OSTI)

    Singh, Subhash C.; Gopal, Ram [Laser Spectroscopy and Nanomaterials Lab, Department of Physics, University of Allahabad, Allahabad-211002 (India)

    2008-11-14

    Laser produced spectra of zinc molecule have been recorded in the region of 540-670 nm using second harmonics of Nd: YAG laser, computer--controlled TRIAX 320 M monochromator with a reciprocal linear dispersion 2.64 nm/mm fitted with ICCD detector. The spectrum consists of 35 bands, which are classified into D ({sup 1} product {sub u}){yields}A({sup 3} product {sub g}) and C ({sup 1}{sigma}{sub u}{sup +}){yields}A({sup 3} product {sub g}) systems. We have recorded the florescence spectrum of zinc dimer by pumping and probing with the same laser, which proves that produced molecules are stable for more than 0.1 seconds.

  2. Flame front tracking by laser induced fluorescence spectroscopy and advanced

    E-Print Network [OSTI]

    Hamarneh, Ghassan

    surface characteristics in turbulent premixed propane/air combustion," Combustion and Flame 120(4), 407 References and links 1. J. Warnatz, U. Maas, and R.W. Dibble, Combustion - physical and chemical fundamentals, "Characterization of flame front surfaces in turbulent premixed methane/air combustion," Combustion and Flame 101

  3. 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.

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

    DOE Patents [OSTI]

    Vo-Dinh, Tuan (Knoxville, TN); Panjehpour, Masoud (Knoxville, TN); Overholt, Bergein F. (Knoxville, TN)

    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.

  5. Visualization of laser-induced breakdown and Ying-Ling Chen and J. W. L. Lewis

    E-Print Network [OSTI]

    Davis, Lloyd M.

    -going simulation modeling of laser-ignition. © 2001 Optical Society of American OCIS codes: (140.3440) Laser detonation wave for supersonic combustion. III," AIAA, 28th AIAA/SAE/ASME/ASEE joint propulsion Conference

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

    DOE Patents [OSTI]

    Ronn, Avigdor M. (Great Neck, NY)

    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.

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

    DOE Patents [OSTI]

    Ebinger, Michael H. (Santa Fe, NM); Harris, Ronny D. (Los Alamos, NM)

    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.

  8. Effect of temperature and CO2 concentration on laser-induced breakdown

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfate Reducing(Journal Article) | SciTech ConnectExperimentsGAMMA-RAYNp, Pu,a model proteina

  9. Laser-induced acoustic wave generation/propagation/interaction in water in various internal channels

    E-Print Network [OSTI]

    2010-01-01

    induced short plane acoustic wave focusing in water. Appl.Laser induced plane acoustic wave generation, propagationAT I O N Laser-induced acoustic wave generation/propagation/

  10. REVIEW ARTICLE Planar laser induced fluorescence in aqueous flows

    E-Print Network [OSTI]

    Crimaldi, John P.

    REVIEW ARTICLE Planar laser induced fluorescence in aqueous flows J. P. Crimaldi Received: 14 for measuring scalar concentra- tions in fluid flows. A fluorescent dye is used as a scalar proxy, and local Osbourne Reynolds performed his famous experiments on laminar and turbulent flow in round pipes (Reynolds

  11. 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.

  12. Interaction between jets during laser-induced forward transfer

    SciTech Connect (OSTI)

    Patrascioiu, A.; Florian, C.; Fernández-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.

  13. Carbon dioxide UV laser-induced fluorescence in high-pressure flames

    E-Print Network [OSTI]

    Lee, Tonghun

    Carbon dioxide UV laser-induced fluorescence in high-pressure flames W.G. Bessler a , C. Schulz a; in final form 16 May 2003 Published online 10 June 2003 Abstract Laser-induced fluorescence (LIF) of carbon dioxide is investigated with excitation between 215 and 255 nm with spectrally resolved detection in 5

  14. 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: dnrsp@uohyd.ac.in, E-mail: dnr-laserlab@yahoo.com [School of Physics, University of Hyderabad, Hyderabad 500046 (India); Deepak, K. L. N. [Department of Physics and Center for Research in Photonics, University of Ottawa, 150 Louis Pasteur, Ottawa K1N6N5, Ontario (Canada)

    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 (C?H?OH) and water (H?O) 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.

  15. Subwavenumber charge-coupled device spectrometer calibration using molecular iodine laser-induced fluorescence

    SciTech Connect (OSTI)

    Lambert, Joseph G. [Department of Physics, Drexel University, Philadelphia, Pennsylvania 19104 (United States); Hernandez-Diaz, Carlos; Williamson, J. Charles [Department of Chemistry, Willamette University, Salem, Oregon 97301 (United States)

    2010-01-15

    Spectrometers configured with charge-coupled devices (CCD) or other array-based detectors require calibration to convert from the pixel coordinate to a spectral coordinate. A CCD calibration method well suited for Raman spectroscopy has been developed based on the 514.5 nm Ar{sup +} laser-induced fluorescence (LIF) spectrum of room-temperature molecular iodine vapor. Over 360 primary and secondary I{sub 2} LIF calibration lines spanning 510-645 nm were identified as calibrant peaks using an instrumental resolution of 1 cm{sup -1}. Two instrument calibration functions were evaluated with these peaks: a second-order polynomial and a function derived from simple optomechanical considerations. The latter function provided better fitting characteristics. Calibration using I{sub 2} LIF was tested with measurements of both laser light scattering and Raman spectra. The I{sub 2} LIF reference spectra and the signal spectra were recorded simultaneously, with no cross talk, by separating the two signals spatially along the vertical axis of the CCD imager. In this way, every CCD image could be independently calibrated. An accuracy and a precision of {+-}0.05 cm{sup -1} were achieved with this calibration technique.

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

    Office of Scientific and Technical Information (OSTI)

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

  17. 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...

  18. NUMERICAL SIMULATION OF VORTEX BREAKDOWN

    E-Print Network [OSTI]

    Prete, Vincenza Del

    2011-01-01

    axis of the tube and is called the vortex core. The basicthe tube plus a perturbation caused by the vortex breakdown.of the tube. Thus the occurrence of the vortex breakdown

  19. NUMERICAL SIMULATION OF VORTEX BREAKDOWN

    E-Print Network [OSTI]

    Prete, Vincenza Del

    2011-01-01

    irrotational vortex. NRC Con. Aero Rep. LR-378. Hald, O. &vortex breakdown" phenomenon. Aero Dept. , Imperial ColI.

  20. Laser-induced synthesis and decay of Tritium under exposure of solid targets in heavy water

    E-Print Network [OSTI]

    E. V. Barmina; P. G. Kuzmin; S. F. Timashev; G. A. Shafeev

    2013-06-03

    The processes of laser-assisted synthesis of Tritium nuclei and their laser-induced decay in cold plasma in the vicinity of solid targets (Au, Ti, Se, etc.) immersed into heavy water are experimentally realized at peak laser intensity of 10E10-10E13 Watts per square centimeter. Initial stages of Tritium synthesis and their laser-induced beta-decay are interpreted on the basis of non-elastic interaction of plasma electrons having kinetic energy of 5-10 eV with nuclei of Deuterium and Tritium, respectively.

  1. Spectroscopy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque|SensitiveApril 2, 2014 Smith NamedDiversityAquiferSpectroscopy

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

    Office of Scientific and Technical Information (OSTI)

    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 laser-induced 6-8 keV...

  3. Work breakdown structure guide

    SciTech Connect (OSTI)

    Not Available

    1987-02-06

    Utilization of the work breakdown structure (WBS) technique is an effective aid in managing Department of Energy (DOE) programs and projects. The technique provides a framework for project management by focusing on the products that are being developed or constructed to solve technical problems. It assists both DOE and contractors in fulfilling their management responsibilities. This document provides guidance for use of the WBS technique for product oriented work identification and definition. It is one in a series of policy and guidance documents supporting DOE's project manaagement system.

  4. Thermal excitation of d band electrons in Au: implications for laser-induced phase transformations

    E-Print Network [OSTI]

    Zhigilei, Leonid V.

    Thermal excitation of d band electrons in Au: implications for laser-induced phase transformations of the electron heat capacity and the electron-phonon coupling factor are investigated for Au based on the electron density of states obtained from ab initio electronic structure calculations. Thermal excitation

  5. Enhancement of high-harmonic generation by laser-induced cluster vibration

    E-Print Network [OSTI]

    Enhancement of high-harmonic generation by laser-induced cluster vibration Yen-Mu Chen,1,2 Ming a new tool for studying the vibrational dynamics of nanometer atomic clusters. © 2007 Optical Society vibration was reported [8], and the results indicate that HHG is a very sensitive probe for vibrational

  6. Laser-induced resonance states as dynamic suppressors of ionization in high-frequency short pulses

    E-Print Network [OSTI]

    Barash, Danny

    distorted to a metastable well form; the electron either tunnels through or crosses over a potential barrier of a laser-induced resonance state, which is coupled by the pulse ramp to the ground state and acts to trap ionizing flux. PACS number s : 32.80.Rm I. INTRODUCTION The interaction of atomic electrons with intense

  7. Laser induced fluorescence of the ferroelectric plasma source assisted hollow anode discharge

    E-Print Network [OSTI]

    the plasma sources described in Refs. 4 and 11­13, where either thermionic cathode or magnetron or arc plasmaLaser induced fluorescence of the ferroelectric plasma source assisted hollow anode discharge V online 20 November 2009 Parameters of the plasma produced by a ferroelectric plasma source FPS assisted

  8. Development of an ion drift chamber for Laser Induced Fluorescence studies 

    E-Print Network [OSTI]

    Cain, Benjamin J

    1998-01-01

    The use of Laser Induced Fluorescence to image ions in a gas has been proposed for a possible new type of subatomic particle detector.1 As a means to investigate this idea, an ion drift chamber has been developed that produces a collimated beam...

  9. Laser-induced forward transfer on compliant receivers M. Feinaeugle1

    E-Print Network [OSTI]

    deposition by the laser-induced forward transfer process," Journal of Vacuum Science & Technology B and thus cause its undesirable shattering. To mitigate this effect, we have introduced a compliant polymer. Flyer velocity, polymer thickness, flyer geometry and Young's modulus were varied and the effect

  10. 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.

  11. 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.}

  12. Use of fiber optic guided, laser induced acoustic waves for nde 

    E-Print Network [OSTI]

    Duffer, Charles Edward

    1990-01-01

    OF SCIENCE December 1990 Major Subject: Mechanical Engineering USE OF FIBER OPTIC GUIDED, LASER INDUCED ACOUSTIC WAVES FOR NDE A Thesis by CHARLES EDWARD DUFFER Approved as to style and content by: Christian P. Burger (Chair of Committee) Peter... USING FIBER BUNDLES EXPERIMENTAL SET-UP EXPERIMENTAL PARAMETERS DATA ANALYSIS Time Domain Results Post Processing Frequency Domain Results 36 36 39 44 44 47 50 TABLE OF CONTENTS (CONTINUED) CHAPIER V RESEARCH APPLICATION COMBINATION...

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

    SciTech Connect (OSTI)

    Oumeziane, Amina Ait, E-mail: a.aitoumeziane@gmail.com; Liani, Bachir [Laboratoire de Physique Théorique, Abou Beker Blekaid University, Tlemcen (Algeria)] [Laboratoire de Physique Théorique, Abou Beker Blekaid University, Tlemcen (Algeria); Parisse, Jean-Denis [IUSTI UMR CNRS 7343, Aix-Marseille University, Marseille (France)] [IUSTI UMR CNRS 7343, Aix-Marseille University, Marseille (France)

    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.

  14. Appl Phys B (2012) 107:873880 DOI 10.1007/s00340-012-4997-6

    E-Print Network [OSTI]

    Harilal, S. S.

    2012-01-01

    of the spot sizes, inter-pulse delay times, energies of the preheating and re- heating pulses on the LIBS reheating in dual-pulse laser-induced breakdown spectroscopy R.W. Coons · S.S. Harilal · S.M. Hassan · A © Springer-Verlag 2012 Abstract Dual-pulse laser-induced breakdown spectrosco- py (LIBS) provides improved

  15. Coherent Raman spectroscopy of A. Rubano,1 D. Paparo,2 F. Miletto Granozio,2 U. Scotti di Uccio,2,3

    E-Print Network [OSTI]

    Marrucci, Lorenzo

    ­667 (2000). 5. D. S. Chemla and J. Shah, "Many-body and correlation effects in semiconductors," Nature 411 Raman spectroscopy of high-temperature superconductors," in Handbook of vibrational spectroscopy, J. M in semiconductors," J. Appl. Phys. 70, 4317­4321 (1991). 15. B. Fainberg, "Laser-induced grating spectroscopy

  16. 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.

  17. 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.; Théberge, 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 (25–300 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.

  18. 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.

  19. Laser-induced damage threshold of silicon in millisecond, nanosecond, and picosecond regimes

    SciTech Connect (OSTI)

    Wang, X.; Shen, Z. H.; Lu, J.; Ni, X. W. [School of Science, Nanjing University of Science and Technology, Nanjing 210094 (China)

    2010-08-15

    Millisecond, nanosecond, and picosecond laser pulse induced damage thresholds on single-crystal are investigated in this study. The thresholds of laser-induced damage on silicon are calculated theoretically for three pulse widths based on the thermal damage model. An axisymmetric mathematical model is established for the transient temperature field of the silicon. Experiments are performed to test the damage thresholds of silicon at various pulse widths. The results indicate that the damage thresholds obviously increase with the increasing of laser pulse width. Additionally, the experimental results agree well with theoretical calculations and numerical simulation results.

  20. Trace Detection of Metastable Helium Molecules in Superfluid Helium by Laser-Induced Fluorescence

    E-Print Network [OSTI]

    D. N. McKinsey; W. H. Lippincott; J. Nikkel; W. Rellergert

    2005-03-11

    We describe an approach to detecting ionizing radiation that combines the special properties of superfluid helium with the sensitivity of quantum optics techniques. Ionization in liquid helium results in the copious production of metastable helium molecules, which can be detected by laser-induced fluorescence. Each molecule can be probed many times using a cycling transition, resulting in the detection of individual molecules with high signal to noise. This technique could be used to detect neutrinos, weakly interacting massive particles, and ultracold neutrons, and to image superfluid flow in liquid He-4.

  1. J. Phys. B AL Mol. Opt Phys. 26 (1993) 1569-1578. Printed in the UK Pure and mixed state calculationsof the laser-induced

    E-Print Network [OSTI]

    Ford, Ian

    1993-01-01

    calculationsof the laser-induced ionizationof uranium I J Ford Theoretical Studies DepartmenL AEA lndusuial 1993 Abstracr In calculations of !he laser-induced ionizalion of uranium atoms it is necessary of the isotopes of uranium has major commercial importance in the nuclear fuel industry. As is well known

  2. Local laser induced rapid thermal oxidation of SOI substrates , R.A. Deutschmann, R. Neumann, K. Brunner, G. Abstreiter

    E-Print Network [OSTI]

    Deutschmann, Rainer

    Local laser induced rapid thermal oxidation of SOI substrates M. Huber* , R.A. Deutschmann, R by a focused laser beam. By focusing the cw light of an argon ion laser at a wavelength of 458 nm (514 nm) we achieve a diffraction limited laser spot of 315 nm (350 nm). The laser spot is scanned over the surface

  3. Fourth-order coherence-function theory of laser-induced molecular reorientational grating and population grating

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    2089 Fourth-order coherence-function theory of laser-induced molecular reorientational grating mécanisme de formation du réseau de population. Abstract. 2014 We have employed fourth-order coherence proposed to distinguish molecular reorientational grating from thermal grating. We then apply the fourth

  4. Laser-induced radial birefringence and spin-to-orbital optical angular momentum conversion in silver-doped glasses

    E-Print Network [OSTI]

    Marrucci, Lorenzo

    Laser-induced radial birefringence and spin-to-orbital optical angular momentum conversion Studies in Basic Sciences (IASBS), 45137-66731 Zanjan, Iran 2 Dipartimento di Scienze Fisiche, Universita online 8 July 2011) Samples of Agþ /Naþ ion-exchanged glass that have been subject to intense laser

  5. Surrogate Hamiltonian study of electronic relaxation in the femtosecond laser induced desorption of NONiO,,100...

    E-Print Network [OSTI]

    Koch, Christiane

    and configuration interaction calculations. Due to the localized electronic structure of NiO a direct optical to calculate the desorption dynamics. Desorption probabilities of the right order of magnitude and velocitiesSurrogate Hamiltonian study of electronic relaxation in the femtosecond laser induced desorption

  6. Laser-Induced Fluorescence Measurement of the Ion-Energy-Distribution Function in a Collisionless Reconnection Experiment

    E-Print Network [OSTI]

    Egedal, Jan

    Laser-Induced Fluorescence Measurement of the Ion-Energy-Distribution Function in a Collisionless for Plasma Physics, EURATOM Association, Greifswald 17491, Germany 2 Massachusetts Institute of Technology], which makes the reconnection drive independent from plasma production. For the present study

  7. Polarization dependent formation of femtosecond laser-induced periodic surface structures near stepped features

    SciTech Connect (OSTI)

    Murphy, Ryan D. [Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States); Torralva, Ben [Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Adams, David P. [Sandia National Laboratories, Albuquerque, New Mexico 87123 (United States); Yalisove, Steven M. [Department of Materials Science and Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2014-06-09

    Laser-induced periodic surface structures (LIPSS) are formed near 110?nm-tall Au microstructured edges on Si substrates after single-pulse femtosecond irradiation with a 150 fs pulse centered near a 780 nm wavelength. We investigate the contributions of Fresnel diffraction from step-edges and surface plasmon polariton (SPP) excitation to LIPSS formation on Au and Si surfaces. For certain laser polarization vector orientations, LIPSS formation is dominated by SPP excitation; however, when SPP excitation is minimized, Fresnel diffraction dominates. The LIPSS orientation and period distributions are shown to depend on which mechanism is activated. These results support previous observations of the laser polarization vector influencing LIPSS formation on bulk surfaces.

  8. 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.

  9. Time-resolved measurement of single pulse femtosecond laser-induced periodic surface structure formation

    E-Print Network [OSTI]

    Kafka, K R P; Li, H; Yi, A; Cheng, J; Chowdhury, E A

    2015-01-01

    Time-resolved diffraction microscopy technique has been used to observe the formation of laser-induced periodic surface structures (LIPSS) from the interaction of a single femtosecond laser pulse (pump) with a nano-scale groove mechanically formed on a single-crystal Cu substrate. The interaction dynamics (0-1200 ps) was captured by diffracting a time-delayed, frequency-doubled pulse from nascent LIPSS formation induced by the pump with an infinity-conjugate microscopy setup. The LIPSS ripples are observed to form sequentially outward from the groove edge, with the first one forming after 50 ps. A 1-D analytical model of electron heating and surface plasmon polariton (SPP) excitation induced by the interaction of incoming laser pulse with the groove edge qualitatively explains the time-evloution of LIPSS formation.

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

    SciTech Connect (OSTI)

    Choi, Sungho [Graduate School of Mechanical Engineering, Hanyang University, Seoul 133–791 (Korea, Republic of); Jhang, Kyung-Young, E-mail: kyjhang@hanyang.ac.kr [School of Mechanical Engineering, Hanyang University, Seoul 133–791 (Korea, Republic of)

    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.

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

    SciTech Connect (OSTI)

    Skolski, J. Z. P., E-mail: j.z.p.skolski@utwente.nl; Vincenc Obona, J. [Materials innovation institute M2i, Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Römer, G. R. B. E.; Huis in 't Veld, A. J. [Faculty of Engineering Technology, Chair of Applied Laser Technology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands)

    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.

  12. Imaging an aligned polyatomic molecule with laser-induced electron diffraction

    E-Print Network [OSTI]

    Pullen, Michael; Le, Anh-Thu; Baudisch, Matthias; Hemmer, Michaël; Senftleben, Arne; Schröter, Claus Dieter; Ullrich, Joachim; Moshammer, Robert; Lin, Chii-Dong; Biegert, Jens

    2015-01-01

    Laser-induced electron diffraction is an evolving tabletop method, which aims to image ultrafast structural changes in gas-phase polyatomic molecules with sub-{\\AA}ngstr\\"om spatial and femtosecond temporal resolution. Here, we provide the general foundation for the retrieval of multiple bond lengths from a polyatomic molecule by simultaneously measuring the C-C and C-H bond lengths in aligned acetylene. Our approach takes the method beyond the hitherto achieved imaging of simple diatomic molecules and is based upon the combination of a 160 kHz mid-IR few-cycle laser source with full three-dimensional electron-ion coincidence detection. Our technique provides an accessible and robust route towards imaging ultrafast processes in complex gas phase molecules with atto- to femto-second temporal resolution.

  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 Maxwell’s 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. 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 Maxwell’s 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 expectedmore »to be substantially lower than assuming complete scattering from the total visible footprint of the pits.« less

  15. Annual Report 2005 SPACE INSTITUTE

    E-Print Network [OSTI]

    Davis, Lloyd M.

    launched an effort in laser induced breakdown spectroscopy for two-phase, time-dependant rocket combustion University of Technology, Warsaw, Poland, by way of CFD Research in Huntsville, Alabama. These individuals

  16. ExecutiveSummary Applications

    E-Print Network [OSTI]

    Davis, Lloyd M.

    launched an effort in laser induced breakdown spectroscopy for two-phase, time-dependant rocket combustion University of Technology, Warsaw, Poland, by way of CFD Research in Huntsville, Alabama. These individuals

  17. 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.

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

    SciTech Connect (OSTI)

    Bataviciute, Gintare; Grigas, Povilas; Smalakys, Linas; Melninkaitis, Andrius [Laser Research Center, Vilnius University, Sauletekio al. 10, LT-10223 Vilnius (Lithuania)

    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).

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

    SciTech Connect (OSTI)

    Wagner, Frank R., E-mail: frank.wagner@fresnel.fr; Natoli, Jean-Yves; Akhouayri, Hassan; Commandré, Mireille [Institut Fresnel, CNRS, Aix-Marseille Université, Ecole Centrale Marseille, Campus de St Jérôme, 13013 Marseille (France); Duchateau, Guillaume [CELIA, UMR 5107 Université Bordeaux 1-CNRS-CEA, 351 Cours de la Libération, 33405 Talence Cedex (France)

    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.

  20. 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. [CIC microGUNE, Goiru Kalea 9 Polo Innovación Garaia, 20500 Arrasate-Mondragón (Spain); CEIT-IK4 and Tecnun, University of Navarra, Manuel Lardizábal 15, 20018 San Sebastián (Spain); Rodriguez, A. [CIC microGUNE, Goiru Kalea 9 Polo Innovación Garaia, 20500 Arrasate-Mondragón (Spain)

    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.

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

    DOE Patents [OSTI]

    Bolton, Paul R. (Menlo Park, CA)

    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.

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

    SciTech Connect (OSTI)

    Petrovi?, Suzana M.; Gakovi?, B.; Peruško, 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. DOE Work Breakdown Structure Handbook | Department of Energy

    Office of Environmental Management (EM)

    Work Breakdown Structure Handbook DOE Work Breakdown Structure Handbook This handbook provides suggested guidance and best practices on the development of product-oriented Work...

  4. 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...

  5. Time-resolved spectroscopy of CI and CII line emissions from an ultrafast laser induced solid graphite plasma

    SciTech Connect (OSTI)

    N, Smijesh, E-mail: smiju5247@gmail.com [Lasers and Nonlinear optics lab, Department of Physics, National Institute of Technology Calicut, Kozhikode - 673 601 India and Raman Research Institute, Sadashivanagar, Bangalore 560080 (India); K, Chandrasekharan, E-mail: csk@nitc.ac.in [Lasers and Nonlinear optics lab, Department of Physics, National Institute of Technology Calicut, Kozhikode - 673 601 (India); Philip, Reji, E-mail: reij@rri.res.in [Raman Research Institute, Sadashivanagar, Bangalore 560080 (India)

    2014-10-15

    We present an experimental characterization of the evolution dynamics of CI and CII lines in an ultrafast laser produced graphite plasma under various ambient conditions. Fast and slow components are observed in the temporal evolution of CI transition at 658.7 nm (3p{sup 1}P - 4d{sup 1}P{sup 0}) and CII transition at 426.7 nm (3d {sup 2}D - 4f {sup 2}F{sup 0}). Fast peak is due to the recombination of fast ions species with electrons, found to have an increase in velocity upon increasing the ambient pressure. Whereas the slow peaks in both cases can be the results of slow ions or slow neutrals in the plume.

  6. Analysis of oil flow mechanisms in internal combustion engines via high speed Laser Induced Fluorescence (LIF) spectroscopy

    E-Print Network [OSTI]

    Zanghi, Eric (Eric James)

    2014-01-01

    Automotive manufacturers have a significant challenge ahead of them with new more stringent regulations for exhaust emissions and fuel economy being implemented in the coming future. To make an impact on current emissions ...

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

    DOE Patents [OSTI]

    Snyder, Stuart C. (Idaho Falls, ID); Partin, Judy K. (Idaho Falls, ID); Grandy, Jon D. (Idaho Falls, ID); Jeffery, Charles L. (Blackfoot, ID)

    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.

  8. Quantitative Outgassing studies in DC Electrical breakdown

    E-Print Network [OSTI]

    Levinsen, Yngve Inntjore; Calatroni, Sergio; Taborelli, Mauro; Wünsch, Walter

    2010-01-01

    Breakdown in the accelerating structures sets an important limit to the performance of the CLIC linear collider. Vacuum degradation and subsequent beam instability are possible outcomes of a breakdown if too much gas is released from the cavity surface. Quantitative data of gas released by breakdowns are provided for copper (milled Cu-OFE, as-received and heat-treated), and molybdenum. These data are produced in a DC spark system based on a capacitance charged at fixed energy, and will serve as a reference for the vacuum design of the CLIC accelerating structures.

  9. Microwave gas breakdown in elliptical waveguides

    SciTech Connect (OSTI)

    Koufogiannis, I. D.; Sorolla, E., E-mail: eden.sorolla@epfl.ch; Mattes, M. [École Polytechnique Fédérale de Lausanne, Laboratoire d’Électromagnétisme et d'Acoustique (LEMA), Station 11, CH-1015 Lausanne (Switzerland)] [École Polytechnique Fédérale de Lausanne, Laboratoire d’Électromagnétisme et d'Acoustique (LEMA), Station 11, CH-1015 Lausanne (Switzerland)

    2014-01-15

    This paper analyzes the microwave gas discharge within elliptical waveguides excited by the fundamental mode. The Rayleigh-Ritz method has been applied to solve the continuity equation. The eigenvalue problem defined by the breakdown condition has been solved and the effective diffusion length of the elliptical waveguide has been calculated, what is used to find the corona threshold. This paper extends the microwave breakdown model developed for circular waveguides and shows the better corona withstanding capabilities of elliptical waveguides. The corona breakdown electric field threshold obtained with the variational method has been compared with the one calculated with the Finite Elements Method, showing excellent agreement.

  10. [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.

  11. 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.

  12. Formation of laser-induced periodic surface structures on fused silica upon two-color double-pulse irradiation

    SciTech Connect (OSTI)

    Höhm, S.; Herzlieb, M.; Rosenfeld, A. [Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Straße 2A, D-12489 Berlin (Germany)] [Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie (MBI), Max-Born-Straße 2A, D-12489 Berlin (Germany); Krüger, J.; Bonse, J. [BAM Bundesanstalt für Materialforschung und –prüfung, Unter den Eichen 87, D-12205 Berlin (Germany)] [BAM Bundesanstalt für Materialforschung und –prüfung, Unter den Eichen 87, D-12205 Berlin (Germany)

    2013-12-16

    The formation of laser-induced periodic surface structures (LIPSS) upon irradiation of fused silica with multiple irradiation sequences consisting of laser pulse pairs (50 fs single-pulse duration) of two different wavelengths (400 and 800 nm) is studied experimentally. Parallel polarized double-pulse sequences with a variable delay ?t between ?10 and +10 ps and between the individual fs-laser pulses were used to investigate the LIPSS periods versus ?t. These two-color experiments reveal the importance of the ultrafast energy deposition to the silica surface by the first laser pulse for LIPSS formation. The second laser pulse subsequently reinforces the previously seeded spatial LIPSS frequencies.

  13. 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.

  14. 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 investigation demonstrates the potential for the optimization and validation of more sophisticated bioheat models that incorporate the uncertainty of the data into the predictions, e.g. stochastic finite element methods.

  15. Breakdown of Stokes-Einstein relation in supercooled water

    E-Print Network [OSTI]

    Pradeep Kumar

    2007-02-06

    Water displays breakdown of the Stokes-Einstein relation at low temperatures. We hypothesize that the breakdown is a result of the structural changes and a sharp rise in dynamic heterogeneities that occurs low T upon crossing the Widom line.

  16. 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.

  17. 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.

  18. Mixing and Reaction Enhancement Characteristics of Laser-Induced Plasmas and Detonations in Laser-Augmented Scramjets

    SciTech Connect (OSTI)

    Negishi, Junya; Horisawa, Hideyuki [Dept. Aeronautics and Astronautics, Tokai University, 1117 Kitakaname, Hiratsuka, Kanagawa, JAPAN 259-1292 (Japan); Kimura, Itsuro [University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8856 (Japan)

    2006-05-02

    CFD simulations using a time-dependant Navier-Stokes equation with finite-rate chemistry on effects of a focused laser pulse for combustion and mixing enhancement characteristics were conducted for supersonic premixed hydrogen-air streams. From the results, it was confirmed that, depending on the laser energy density, radicals, a shock wave, and shock-induced local turbulences were being formed through the laser irradiation. Then recirculation zones with flamelets were induced. Moreover it was shown that these flamelets in the recirculation zones were being stabilized in the supersonic stream for a while. Consequently, it was shown that laser-induced plasmas could be effective in both combustion reaction and mixing enhancements for the supersonic combustion.

  19. 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).

  20. 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.

  1. 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.

  2. 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).

  3. 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 1.3 GHz RF test cell capable of operating both at high pressure and in vacuum with replaceable electrodes was designed, built, and power tested in preparation for testing the frequency and geometry effects of RF breakdown at Argonne National Lab. At the time of this report this cavity is still waiting for the 1.3 GHz klystron to be available at the Wakefield Test Facility. (3) Under a contract with Los Alamos National Lab, an 805 MHz RF test cavity, known as the All-Seasons Cavity (ASC), was designed and built by Muons, Inc. to operate either at high pressure or under vacuum. The LANL project to use the (ASC) was cancelled and the testing of the cavity has been continued under the grant reported on here using the Fermilab Mucool Test Area (MTA). The ASC is a true pillbox cavity that has performed under vacuum in high external magnetic field better than any other and has demonstrated that the high required accelerating gradients for many muon cooling beam line designs are possible. (4) Under ongoing support from the Muon Acceleration Program, microscopic surface analysis and computer simulations have been used to develop models of RF breakdown that apply to both pressurized and vacuum cavities. The understanding of RF breakdown will lead to better designs of RF cavities for many applications. An increase in the operating accelerating gradient, improved reliability and shorter conditioning times can generate very significant cost savings in many accelerator projects.

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

    SciTech Connect (OSTI)

    Gan, Li, E-mail: ligan0001@gmail.com; Mousen, Cheng; Xiaokang, Li [College of Aerospace Science and Engineering, National University of Defense Technology, Changsha (China)] [College of Aerospace Science and Engineering, National University of Defense Technology, Changsha (China)

    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.

  6. 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 ?s. 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

  7. 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.

  8. Spectroscopy and reactions of vibrationally excited transient molecules

    SciTech Connect (OSTI)

    Dai, H.L. [Univ. of Pennsylvania, Philadelphia (United States)

    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.

  9. 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.

  10. Soot particle sizing during high-pressure Diesel spray combustion via time-resolved laser-induced incandescence

    SciTech Connect (OSTI)

    Ryser, R.; Gerber, T.; Dreier, T. [Reaction Analysis Group, Department of General Energy, Paul Scherrer Institute, CH-5232 Villigen (Switzerland)

    2009-01-15

    Single-pulse time-resolved laser-induced incandescence (TiRe-LII) signal transients from soot particulates were acquired during unsteady high pressure Diesel combustion in a constant volume cell for typical top dead center conditions during a Diesel engine cycle. Measurements were performed for initial gas pressures between 1 and 3 MPa, injection pressures between 50 and 130 MPa and laser probe timings between 5 and 16 ms after start of fuel injection. In separate experiments and for the same cell operating conditions gas temperatures were deduced from spectrally resolved soot pyrometry measurements. Implementing the LII model of Kock et al. [Combust. Flame 147 (20006) 79-92] ensemble mean soot particle diameters were evaluated from least-squares fitting of theoretical cooling curves to experimental TiRe-LII signal transients. Since in the experiments the environmental gas temperature and the width of an assumed particle size distribution were not known, the effects of the initial choice of these parameters on retrieved particle diameters were investigated. It is shown that evaluated mean particle diameters are only slightly biased by the choice of typical size distribution widths and gas temperatures. For a fixed combustion phase mean particle diameters are not much affected by gas pressure, however they become smaller at high fuel injection pressure. At a mean chamber pressure of 1.39 MPa evaluated mean particle diameters increased by a factor of two for probe delays between 5 and 16 ms after start of injection irrespective of the choices of first-guess fitting variables, indicating a certain robustness of data analysis procedure. (author)

  11. Soot particle sizing during high-pressure Diesel spray combustion via time-resolved laser-induced incandescence

    SciTech Connect (OSTI)

    Ryser, R.; Gerber, T.; Dreier, T. [Reaction Analysis Group, Department of General Energy, Paul Scherrer Institute, CH-5232 Villigen PSI (Switzerland)

    2008-11-15

    Single-pulse time-resolved laser-induced incandescence (TiRe-LII) signal transients from soot particulates were acquired during unsteady high pressure Diesel combustion in a constant volume cell for typical top dead center conditions during a Diesel engine cycle. Measurements were performed for initial gas pressures between 1 and 3 MPa, injection pressures between 50 and 130 MPa and laser probe timings between 5 and 16 ms after start of fuel injection. In separate experiments and for the same cell operating conditions gas temperatures were deduced from spectrally resolved soot pyrometry measurements. Implementing the LII model of Kock et al. [Combust. Flame 147 (2006) 79-92] ensemble mean soot particle diameters were evaluated from least-squares fitting of theoretical cooling curves to experimental TiRe-LII signal transients. Since in the experiments the environmental gas temperature and the width of an assumed particle size distribution were not known, the effects of the initial choice of these parameters on retrieved particle diameters were investigated. It is shown that evaluated mean particle diameters are only slightly biased by the choice of typical size distribution widths and gas temperatures. For a fixed combustion phase mean particle diameters are not much affected by gas pressure, however they become smaller at high fuel injection pressure. At a mean chamber pressure of 1.39 MPa evaluated mean particle diameters increased by a factor of two for probe delays between 5 and 16 ms after start of injection irrespective of the choices of first-guess fitting variables, indicating a certain robustness of data analysis procedure. (author)

  12. 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.

  13. 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 (??? = 0.4–3 cm{sup ?1}) infrared lasers.

  14. Relationship Between Honeycombing and Collagen Breakdown in Skipjack Tuna, Katsuwonus pelamis

    E-Print Network [OSTI]

    Relationship Between Honeycombing and Collagen Breakdown in Skipjack Tuna, Katsuwonus pelamis between the amount of honeycombing and collagen breakdown in skipjack tuna, Kat- suwonus pelamis

  15. Laser induced chemical reactions

    E-Print Network [OSTI]

    Orel, Ann E.

    2010-01-01

    the simplest prototype chemical reaction, and since it is soLASER ENHANCEMENT OF CHEMICAL REACTIONS A. B. C. D. E.Laser Inhibition of Chemical Reaction Effect of Isotopic

  16. Cone penetrometer fiber optic raman spectroscopy probe assembly

    DOE Patents [OSTI]

    Kyle, Kevin R. (Brentwood, CA); Brown, Steven B. (Livermore, CA)

    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.

  17. Breakdown Anodization (BDA) for hierarchical structures of titanium oxide

    E-Print Network [OSTI]

    Choi, Soon Ju, S.M. Massachusetts Institute of Technology

    2013-01-01

    Breakdown Anodization (BDA) of titanium dioxide is a very promising, fast fabrication method to construct micro-scale and nano-scale structures on titanium surfaces. This method uses environmentally friendly electrolytes, ...

  18. Evaluation of the irising effect of a slow-gating intensified charge-coupled device on laser-induced incandescence measurements of soot

    SciTech Connect (OSTI)

    Shaddix, Christopher R.; Williams, Timothy C. [Combustion Research Facility, Sandia National Laboratories, 7011 East Avenue, Livermore, California 94550 (United States)

    2009-03-15

    Intensified charge-coupled devices (ICCDs) are used extensively in many scientific and engineering environments to image weak or temporally short optical events. To optimize the quantum efficiency of light collection, many of these devices are chosen to have characteristic intensifier gate times that are relatively slow, on the order of tens of nanoseconds. For many measurements associated with nanosecond laser sources, such as scattering-based diagnostics and most laser-induced fluorescence applications, the signals rise and decay sufficiently fast during and after the laser pulse that the intensifier gate may be set to close after the cessation of the signal and still effectively reject interferences associated with longer time scales. However, the relatively long time scale and complex temporal response of laser-induced incandescence (LII) of nanometer-sized particles (such as soot) offer a difficult challenge to the use of slow-gating ICCDs for quantitative measurements. In this paper, ultraviolet Rayleigh scattering imaging is used to quantify the irising effect of a slow-gating scientific ICCD camera, and an analysis is conducted of LII image data collected with this camera as a function of intensifier gate width. The results demonstrate that relatively prompt LII detection, generally desirable to minimize the influences of particle size and local gas pressure and temperature on measurements of the soot volume fraction, is strongly influenced by the irising effect of slow-gating ICCDs.

  19. 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.

  20. Neutral multi-MeV/u particles from laser-induced processes in ultra-dense deuterium D(0): accurate two-collector timing and magnetic analysis

    E-Print Network [OSTI]

    Leif Holmlid

    2015-08-06

    Laser-induced processes in ultra-dense deuterium D(0) layers eject multi-MeV u-1 particles using ns laser pulse energies of energy of the particles is in the range 1-50 MeV u-1. Their distributions are almost thermal at up to 13 MeV u-1 or are sharper than thermal. The fastest sharp peak may indicate shock-wave acceleration by many-body energy transfer. A magnetic field of 0.4 T deflects only a small part of the multi-MeV particle flux which thus mainly consists of neutral particles. By combining the TOF method with magnetic deflection, it is ascertained that the multi-MeV particles are studied and not any slower particle emission from the target. The neutral multi-MeV particles are concluded to be fragments of ultra-dense hydrogen HN(0) as observed in other experiments.

  1. Neutral multi-MeV/u particles from laser-induced processes in ultra-dense deuterium D(0): accurate two-collector timing and magnetic analysis

    E-Print Network [OSTI]

    Holmlid, Leif

    2015-01-01

    Laser-induced processes in ultra-dense deuterium D(0) layers eject multi-MeV u-1 particles using ns laser pulse energies of energy of the particles is in the range 1-50 MeV u-1. Their distributions are almost thermal at up to 13 MeV u-1 or are sharper than thermal. The fastest sharp peak may indicate shock-wave acceleration by many-body energy transfer. A magnetic field of 0.4 T deflects only a small part of the multi-MeV particle flux which thus mainly consists of neutral particles. By combining the TOF method with magnetic deflection, it is ascertained that the multi-MeV particles are studied and not any slower particle emission from the target. The neutral multi-MeV particles are concluded to be...

  2. 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.

  3. 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 magnetic field spreads from the hot spot over the surface that contains the toroidal gap, it will propagate through the gap and set up a steady state in the capsule. The main compression is then initiated. First, it closes the gap and crow-bars the field, then it compresses the fuel to ignition. In addition to this application, we discuss the use of this mechanism to induce Mega-gauss fields in laboratory apparatus for measurements of the effects of large magnetic fields on material samples. A preliminary target design for this purpose is presented. It is made of high-density material with no hydrogen surface contamination to minimize fast ion losses and to minimize x-ray preheat of the sample (the material, whose magnetic properties are to be measured). In it, the gap is designed to allow the magnetic field to move into the interior of the target while minimizing the flow of hot electrons into the interior. By adjusting the size of the gap as well as its configuration, the hot electron effects can be minimized. Since the strength of the magnetic field depends on the radial distance to the sample from the center of the conductor carrying the return current, the sample is located at a point of minimum conductor radius. This location also minimizes the effects on the measurement of any hot electrons that flow into the interior. Useful experiments can be accomplished with the “seed” field alone in this geometry. Compressing the capsule after the insertion of the seed field may allow experiments with even larger magnetic fields. We have used computer-simulation techniques to address a number of issues. Our conclusions include: • This magnetic-field generating mechanism is a viable method for generating magnetic fields in ICF targets and for laboratory experiments. • Useful experiments on material samples can be done with the seed field of 1 to10 Mega gauss (100 to 1000 Tesla) and higher magnetic fields can be obtained by subsequently compressing the capsule. • The results reported here can be studied experimentally with a modest CO2 laser that emits 4.5 J of ene

  4. 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.

  5. AirUCI Summer 2010 Schedule Monday, June 28

    E-Print Network [OSTI]

    Nizkorodov, Sergey

    concerns at surface interfaces - Catalysts and catalytic converters (p. 18 & 109­114) - Solar energy Hemminger on the energy science policy and the importance of basic research in dealing with the combined pollution - Laser­Induced Breakdown Spectroscopy (LIBS) of common materials · Common lab techniques

  6. AirUCI Summer Training Workshop in Environmental

    E-Print Network [OSTI]

    Nizkorodov, Sergey

    of Catalytic Converters to Reduce Air Pollution NOx PC Lab: Air PSE (Problem Solving Environment) PSE PC Lab - Ability of catalytic converters to reduce air pollution - Laser­Induced Breakdown Spectroscopy (LIBS to 10 am: Room Rowland Hall 390 · Lecture by Prof. Sergey Nizkorodov - The use of light in analytical

  7. AirUCI Summer Institute 2012 Schedule Monday, June 25

    E-Print Network [OSTI]

    Nizkorodov, Sergey

    by FTIR - Ability of catalytic converters to reduce air pollution - Laser­Induced Breakdown Spectroscopy - The use of light in analytical chemistry - Absorption of light and Beer's Law (p.6­9, 177­179, 184­Pitts - Light and Photochemistry (p. 6­7 and 13­16) - The Chapman reactions (p. 16­20), CFC's (p. 29, 55

  8. IOP PUBLISHING JOURNAL OF PHYSICS D: APPLIED PHYSICS J. Phys. D: Appl. Phys. 44 (2011) 355203 (4pp) doi:10.1088/0022-3727/44/35/355203

    E-Print Network [OSTI]

    Harilal, S. S.

    2011-01-01

    hosts multiple colliding plasmas as x-ray sources which are used to drive fusion in a fuel cell located and Technology (NCPST), Dublin City University, Glasnevin, Dublin 9, Ireland 2 School of Nuclear Engineering] and have spawned a wide range of applications including laser induced breakdown spectroscopy, LIBS [2

  9. 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.

  10. Electrical breakdown and ultrahigh electrical energy density in poly,,vinylidene fluoride-hexafluoropropylene... copolymer

    E-Print Network [OSTI]

    Suo, Zhigang

    Electrical breakdown and ultrahigh electrical energy density in poly,,vinylidene fluoride. Zhang1,3,a 1 Department of Electrical Engineering, The Pennsylvania State University, University Park investigates the electrical breakdown of a polar fluoropolymer, poly vinylidene fluoride

  11. Numerical simulation of laserinduced breakdown in Shankar Ghosh

    E-Print Network [OSTI]

    Mahesh, Krishnan

    1999), ignition of combustion gases (Phuoc 2000) and providing thrust to aerospace vehicles (Molina breakdown of air. The laser was pulsed for a duration of 18 nanoseconds. Adelgren et al. (2001) pulsed a Nd. However, experimental data show a wide separation in time­scales of the laser pulse duration and blast

  12. Studies of electrical breakdown processes across vacuum gaps between metallic electrodes

    E-Print Network [OSTI]

    Gilson, Erik

    Studies of electrical breakdown processes across vacuum gaps between metallic electrodes L Available online 3 June 2013 Keywords: Magnetic insulation Vacuum electrical breakdown Bacteria-induced electrical breakdown Accelerator a b s t r a c t An experimental program to elucidate the physical causes

  13. Neutral multi-MeV/u particles from laser-induced processes in ultra-dense deuterium D(0): accurate two-collector timing and magnetic analysis

    E-Print Network [OSTI]

    Leif Holmlid

    2015-08-28

    Laser-induced processes in ultra-dense deuterium D(0) layers eject multi-MeV u-1 particles using ns laser pulse energies of <200 mJ. Such particles have been observed previously as mA currents to time-of-flight (TOF) collectors at up to 1 m distance. The signal current is mainly due to the ejection of secondary electrons by impinging MeV particles on the collectors. Improved two-collector time-of-flight measurements now show that the energy of the particles is in the range 1-50 MeV u-1. Their distributions are almost thermal at up to 13 MeV u-1 or are sharper than thermal. The fastest sharp peak may indicate shock-wave acceleration by many-body energy transfer. A magnetic field of 0.4 T deflects only a small part of the multi-MeV particle flux which thus mainly consists of neutral particles. By combining the TOF method with magnetic deflection, it is ascertained that the multi-MeV particles are studied and not any slower particle emission from the target. The neutral multi-MeV particles are concluded to be fragments of ultra-dense hydrogen HN(0) as observed in other experiments.

  14. Comparison of nanosecond and picosecond excitation for interference-free two-photon laser-induced fluorescence detection of atomic hydrogen in flames

    SciTech Connect (OSTI)

    Kulatilaka, Waruna D.; Patterson, Brian D.; Frank, Jonathan H.; Settersten, Thomas B

    2008-09-10

    Two-photon laser-induced fluorescence (TP-LIF) line imaging of atomic hydrogen was investigated in a series of premixed CH4/O2/N2, H2/O2, and H2/O2/N2 flames using excitation with either picosecond or nanosecond pulsed lasers operating at 205 nm. Radial TP-LIF profiles were measured for a range of pulse fluences to determine the maximum interference-free signal levels and the corresponding picosecond and nanosecond laser fluences in each of 12 flames. For an interference-free measurement, the shape of the TP-LIF profile is independent of laser fluence. For larger fluences, distortions in the profile are attributed to photodissociation of H2O, CH3, and/or other combustion intermediates, and stimulated emission. In comparison with the nanosecond laser, excitation with the picosecond laser can effectively reduce the photolytic interference and produces approximately an order of magnitude larger interference-free signal in CH4/O2/N2 flames with equivalence ratios in the range of 0.5{<=}{phi}{<=}1.4, and in H{sub 2}/O{sub 2} flames with 0.3{<=}{phi}{<=}1.2. Although photolytic interference limits the nanosecond laser fluence in all flames, stimulated emission, occurring between the laser-excited level, H(n=3), and H(n=2), is the limiting factor for picosecond excitation in the flames with the highest H atom concentration. Nanosecond excitation is advantageous in the richest ({phi}=1.64) CH4/O2/N2 flame and in H2/O2/N2 flames. The optimal excitation pulse width for interference-free H atom detection depends on the relative concentrations of hydrogen atoms and photolytic precursors, the flame temperature, and the laser path length within the flame.

  15. 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.

  16. Thermally activated breakdown in a simple polymer model

    E-Print Network [OSTI]

    S. Fugmann; I. M. Sokolov

    2009-10-28

    We consider the thermally activated fragmentation of a homopolymer chain. In our simple model the dynamics of the intact chain is a Rouse one until a bond breaks and bond breakdown is considered as a first passage problem over a barrier to an absorbing boundary. Using the framework of the Wilemski-Fixman approximation we calculate activation times of individual bonds for free and grafted chains. We show that these times crucially depend on the length of the chain and the location of the bond yielding a minimum at the free chain ends. Theoretical findings are qualitatively confirmed by Brownian dynamics simulations.

  17. Breakdown of the Dipole Approximation in Strong-Field Ionization

    E-Print Network [OSTI]

    A. Ludwig; J. Maurer; B. W. Mayer; C. R. Phillips; L. Gallmann; U. Keller

    2014-10-02

    We report the breakdown of the electric dipole approximation in the long-wavelength limit in strong-field ionization with linearly polarized few-cycle mid-infrared laser pulses at intensities on the order of 10$^{13}$ W/cm$^2$. Photoelectron momentum distributions were recorded by velocity map imaging and projected onto the beam propagation axis. We observe an increasing shift of the peak of this projection opposite to the beam propagation direction with increasing laser intensities. From a comparison with semi-classical simulations, we identify the combined action of the magnetic field of the laser pulse and the Coulomb potential as origin of our observations.

  18. 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.

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

    SciTech Connect (OSTI)

    Yang Yiming; Yuan Chengwei; Qian Baoliang [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    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.

  20. 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.

  1. 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.

  2. THE RELATIONSHIP BETWEEN CRYSTALLOGRAPHIC ORIENTATION AND THE PASSIVITY AND BREAKDOWN OF BERYLLIUM

    E-Print Network [OSTI]

    THE RELATIONSHIP BETWEEN CRYSTALLOGRAPHIC ORIENTATION AND THE PASSIVITY AND BREAKDOWN OF BERYLLIUM corrosion for S200D beryllium (Be) was found to decrease logarithmically with increasing chloride

  3. Breakdown of the Stokes-Einstein Relation in Supercooled Water

    E-Print Network [OSTI]

    Pradeep Kumar; S. V. Buldyrev; S. R. Becker; P. H. Poole; F. W. Starr; H. E. Stanley

    2007-02-06

    Supercooled water exhibits a breakdown of the Stokes-Einstein relation between the diffusion constant $D$ and the alpha relaxation time $\\tau_{\\alpha}$. For water simulated with the TIP5P and ST2 potentials, we find that the temperature of the decoupling of diffusion and alpha relaxation correlates with the temperature of the maximum in specific heat that corresponds to crossing the Widom line $T_W(P)$. Specifically, we find that our results for $D\\tau_{\\alpha}/T$ collapse onto a single master curve if temperature is replaced by $T-T_W(P)$, where $T_W(P)$ is the temperature where the constant-pressure specific heat achieves a maximum. Also, we find agreement between our ST2 simulations and experimental values of $D\\tau_{\\alpha}/T$. We further find that the size of the mobile molecule clusters (dynamical heterogeneities) increases sharply near $T_W(P)$. Moreover, our calculations of mobile particle cluster size $_w$ for different pressures, where $t^*$ is the time for which the mobile particle cluster size is largest, also collapse onto a single master curve if $T$ is replaced by $T-T_W(P)$. The crossover to a more locally structured low density liquid (LDL) environment as $T\\to T_W(P)$ appears to be well correlated with both the breakdown of the Stokes-Einstein relation and the growth of dynamic heterogeneities.

  4. Laser induced phosphorescence uranium analysis

    DOE Patents [OSTI]

    Bushaw, Bruce A. (Kennewick, WA)

    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.

  5. 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.

  6. 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.

  7. DOE-Imaging grant FG02-06ER15829, entitled "Developing Laser-Induced Re-Collision Electron Self-Diffraction" Brief summary of accomplishments

    SciTech Connect (OSTI)

    Igor V. Litvinyuk, and Itzik Ben-Itzhak

    2012-04-01

    Our principal goal was the experimental demonstration of Laser-Induced Electron Diffraction (LIED). Key steps along the development of this experimental technique have been accomplished and reported in the publications listed in this brief report. We started with measuring 3D electron momenta spectra in aligned nitrogen and oxygen molecules. Chakra Maharjan (Ph.D. student of Lew Cocke) was a lead researcher on this project. Although Chakra succeeded in obtaining those spectra, we were scooped by the publication of identical results in Science by the NRC Ottawa group. Our results were never published as a refereed article, but became a part of Chakra's Ph.D. dissertation. That Science paper was the first experimental demonstration of Laser-Induced Electron Diffraction (LIED). Chakra also worked on wavelength dependence of 3D ATI spectra of atoms and molecules using tunable OPA pulses. Another Ph.D. student, Maia Magrakvelidze (her GRA was funded by the grant), started working on COLTRIMS experiments using OPA pulses (1800 nm wavelength). After some initial experiments it became apparent that COLTRIMS did not yield sufficient count rates of electrons in the high-energy part of the spectrum to see diffraction signatures with acceptable statistics (unfavorable scaling of the electron yield with laser wavelength was partly to blame). Nevertheless, Maia managed to use COLTRIMS and OPA to measure the angular dependence of the tunneling ionization rate in D{sub 2} molecules. Following the initial trial experiments, the decision was made to switch from COLTRIMS to VMI in order to increase the count rates by a factor of {approx}100, which may have given us a chance to see LIED. Research Associate Dr. Sankar De (his salary was funded by the grant), in collaboration with Matthias Kling's group (then at MPQ Garching), proceeded to design a special multi-electrode VMI spectrometer for capturing high-energy ATI electrons and to install it in place of COLTRIMS inside our experimental chamber. That apparatus was later used for the first demonstration of field-free orientation in CO using two-color laser pulses as well as for a series of other experiments, such as pump-probe studies of molecular dynamics with few-cycle laser pulses, control of electron localization in dissociating hydrogen molecules using two-color laser pulses, and ATI spectra of Xe ionized by two-color laser pulses. In parallel, Dipanwita Ray (Ph.D. student of Lew Cocke) worked on measuring angle-resolved ATI spectra of noble gases using a stereo-ATI phasemeter as a TOF electron spectrometer. She observed the angular diffraction structures in 3D ATI spectra of Ar, Kr and Xe, which were interpreted in terms of the Quantitative Rescattering theory newly developed by C.D. Lin. We also attempted to use a much more powerful OPA (five times more energy per pulse than the one we had at JRML) available at the Advanced Laser Light Source (ALLS) in Montreal to observe LIED. Two visits to ALLS by the PI, Igor Litvinyuk, and one visit by the PI's Ph.D. student (Irina Bocharova) were funded by the grant. Though we failed to observe LIED (the repetition rate of the ALLS OPA was too low at only 100 Hz), this international collaboration resulted in several publications on other related subjects, such as the wavelength dependence of laser Coulomb explosion of hydrogen, the wavelength dependence of non-sequential double ionization of neon and argon, the demonstration of charge-resonance enhanced ionization in CO{sub 2}, and the study of non-elastic scattering processes in H{sub 2}. Theoretical efforts to account for the hydrogen Coulomb explosion experiment resulted in another paper by Maia Magrakvelidze as lead author. Although for various reasons we failed to achieve our main goal of observing LIED, we salute the recent success in this endeavor by Lou DiMauro's group (with theoretical support from our KSU colleague C.D. Lin) published in Nature, which validates our approach.

  8. Positive and negative effects of dielectric breakdown in transformer oil based magnetic fluids

    SciTech Connect (OSTI)

    Lee, Jong-Chul, E-mail: jclee01@gwnu.ac.kr [School of Mechanical and Automotive Engineering, Gangneung-Wonju National University, Wonju 220711 (Korea, Republic of)] [School of Mechanical and Automotive Engineering, Gangneung-Wonju National University, Wonju 220711 (Korea, Republic of); Lee, Won-Ho [Graduate School of Automotive Engineering, Gangneung-Wonju National University, Wonju 220711 (Korea, Republic of)] [Graduate School of Automotive Engineering, Gangneung-Wonju National University, Wonju 220711 (Korea, Republic of); Lee, Se-Hee [Department of Electrical Engineering, Kyungpook National University, Daegu 702701 (Korea, Republic of)] [Department of Electrical Engineering, Kyungpook National University, Daegu 702701 (Korea, Republic of); Lee, Sangyoup, E-mail: sangyoup@kist.re.kr [Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 136791 (Korea, Republic of)] [Biomedical Research Institute, Korea Institute of Science and Technology, Seoul 136791 (Korea, Republic of)

    2012-10-15

    The transformer oil based magnetic fluids can be considered as the next-generation insulation fluids because they offer exciting new possibilities to enhance dielectric breakdown voltage as well as heat transfer performance compared to pure transformer oils. In this study, we have investigated the dielectric breakdown strength of the fluids with the various volume concentrations of nanoparticles in accordance with IEC 156 standard and have tried to find the reason for changing the dielectric breakdown voltage of the fluids from the magnetic field analysis. It was found that the dielectric breakdown voltage of pure transformer oil is around 12 kV with the gap distance of 1.5 mm. In the case of our transformer oil-based magnetic fluids with 0.08% < ? < 0.6% (? means the volume concentration of magnetic nanoparticles), the dielectric breakdown voltage shows above 40 kV, which is 3.3 times higher positively than that of pure transformer oil. Negatively in the case when the volume concentration of magnetic nanoparticles is above 0.65%, the dielectric breakdown voltage decreases reversely. From the magnetic field analysis, the reason might be considered as two situations: the positive is for the conductive nanoparticles dispersed well near the electrodes, which play an important role in converting fast electrons to slow negatively charged particles, and the negative is for the agglomeration of the particles near the electrodes, which leads to the breakdown initiation.

  9. Analysis Code for High Gradient Dielectric Insulator Surface Breakdown

    SciTech Connect (OSTI)

    Ives, Robert Lawrence [Calabazas Creek Research, Inc.; Verboncoeur, John [University of California - Berkeley; Aldan, Manuel [University of California, Berkeley

    2010-05-30

    High voltage (HV) insulators are critical components in high-energy, accelerator and pulsed power systems that drive diverse applications in the national security, nuclear weapons science, defense and industrial arenas. In these systems, the insulator may separate vacuum/non-vacuum regions or conductors with high electrical field gradients. These insulators will often fail at electric fields over an order of magnitude lower than their intrinsic dielectric strength due to flashover at the dielectric interface. Decades of studies have produced a wealth of information on fundamental processes and mechanisms important for flashover initiation, but only for relatively simple insulator configurations in controlled environments. Accelerator and pulsed power system designers are faced with applying the fundamental knowledge to complex, operational devices with escalating HV requirements. Designers are forced to rely on “best practices” and expensive prototype testing, providing boundaries for successful operation. However, the safety margin is difficult to estimate, and system design must be very conservative for situations where testing is not practicable, or replacement of failed parts is disruptive or expensive. The Phase I program demonstrated the feasibility of developing an advanced code for modeling insulator breakdown. Such a code would be of great interest for a number of applications, including high energy physics, microwave source development, fusion sciences, and other research and industrial applications using high voltage devices.

  10. 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...

  11. 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.

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

    Open Energy Info (EERE)

    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 base on a recent...

  13. Charge transport and breakdown physics in liquid/solid insulation systems

    E-Print Network [OSTI]

    Jadidian, Jouya

    2013-01-01

    Liquid dielectrics provide superior electrical breakdown strength and heat transfer capability, especially when used in combination with liquid-immersed solid dielectrics. Over the past half-century, there has been extensive ...

  14. Elucidating the mechanisms behind pre-breakdown phenomena in transformer oil systems

    E-Print Network [OSTI]

    Hwang, Jae-Won George, 1980-

    2010-01-01

    The widespread use of dielectric liquids for high voltage insulation and power apparatus cooling is due to their greater electrical breakdown strength and thermal conductivity than gaseous insulators. In addition, their ...

  15. BREAKDOWN OF LINDSTEDT EXPANSION FOR CHAOTIC MAPS GUIDO GENTILE AND TITUS S. VAN ERP

    E-Print Network [OSTI]

    Roma "La Sapienza", Università di

    BREAKDOWN OF LINDSTEDT EXPANSION FOR CHAOTIC MAPS GUIDO GENTILE AND TITUS S. VAN ERP Abstract; critical constant; natural boundary. 1 #12; 2 GUIDO GENTILE AND TITUS S. VAN ERP The theoretical framework

  16. BREAKDOWN OF LINDSTEDT EXPANSION FOR CHAOTIC MAPS GUIDO GENTILE AND TITUS S. VAN ERP

    E-Print Network [OSTI]

    Gentile, Guido

    BREAKDOWN OF LINDSTEDT EXPANSION FOR CHAOTIC MAPS GUIDO GENTILE AND TITUS S. VAN ERP Abstract; critical constant; natural boundary. 1 #12;2 GUIDO GENTILE AND TITUS S. VAN ERP The theoretical framework

  17. 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.

  18. Sandia Energy - Nonlinear Laser Spectroscopy

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

    Nonlinear Laser Spectroscopy Home Transportation Energy Predictive Simulation of Engines Diagnostics Gas-Phase Diagnostics Nonlinear Laser Spectroscopy Nonlinear Laser...

  19. Microwave breakdown for the TE{sub 10} mode in a rectangular waveguide

    SciTech Connect (OSTI)

    Malik, Hitendra K.; Aria, Anil K. [Plasma Waves and Particle Acceleration Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi–110 016 (India)] [Plasma Waves and Particle Acceleration Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi–110 016 (India)

    2013-08-15

    Microwave breakdown is studied for the lowest order TE{sub 10} mode in a rectangular waveguide with the help of direct variational approach via the continuity equation along with the use of ionisation and attachment frequency. We investigate the role of the ionisation, attachment of electron with neutral gas or air molecules and the diffusion on microwave breakdown threshold in the waveguide filled with air or Ar Gas. We examine the effect of different gases and microwave parameters on the diffusion length and the breakdown threshold of electric field of continuous microwave and pulsed microwave. We also employ numerical approach for obtaining the results and compare them with the ones of variational approach.

  20. In situ study on low-k interconnect time-dependent-dielectric-breakdown mechanisms

    SciTech Connect (OSTI)

    Boon Yeap, Kong, E-mail: KongBoon.Yeap@globalfoundries.com [GLOBALFOUNDRIES, Fab8, 400 Stonebreak Rd. Extension, Malta, New York 12020 (United States); Fraunhofer Institute for Ceramic Technologies and Systems, Maria-Reiche-Str. 2, D-01109 Dresden (Germany); Gall, Martin; Liao, Zhongquan; Sander, Christoph; Muehle, Uwe; Zschech, Ehrenfried [Fraunhofer Institute for Ceramic Technologies and Systems, Maria-Reiche-Str. 2, D-01109 Dresden (Germany); Justison, Patrick [GLOBALFOUNDRIES, Fab8, 400 Stonebreak Rd. Extension, Malta, New York 12020 (United States); Aubel, Oliver; Hauschildt, Meike; Beyer, Armand; Vogel, Norman [GLOBALFOUNDRIES Dresden Module One LLC and Co. KG, Wilschdorfer Landstr. 101, D-01109 Dresden (Germany)

    2014-03-28

    An in situ transmission-electron-microscopy methodology is developed to observe time-dependent dielectric breakdown (TDDB) in an advanced Cu/ultra-low-k interconnect stack. A test structure, namely a “tip-to-tip” structure, was designed to localize the TDDB degradation in small dielectrics regions. A constant voltage is applied at 25?°C to the “tip-to-tip” structure, while structural changes are observed at nanoscale. Cu nanoparticle formation, agglomeration, and migration processes are observed after dielectric breakdown. The Cu nanoparticles are positively charged, since they move in opposite direction to the electron flow. Measurements of ionic current, using the Triangular-Voltage-Stress method, suggest that Cu migration is not possible before dielectric breakdown, unless the Cu/ultra-low-k interconnect stacks are heated to 200?°C and above.

  1. Sparse breakdown and statistical sneakthrough'' effects in low-altitude microwave propagation

    SciTech Connect (OSTI)

    Alvarez, R.A.; Bolton, P.R.; Sieger, G.E.; Fittinghoff, D.N.

    1990-01-01

    It is generally assumed that the beam intensity that can be transmitted through the atmosphere by a high-power microwave pulse will be limited by the air-breakdown threshold. Air breakdown by microwave has been studied extensively, both theoretically and experimentally. It is a cascade process in which free electrons, driven by the microwave electric field, generate further ionization through collisions with air molecules. The process can disrupt the propagation of a microwave pulse if the electron plasma density grows to within an appreciable fraction of critical density. In a pulsed beam this can happen if, and only if, the field strength is sufficiently large and the beam encounters one or more initiating free seed'' electrons sufficiently early in the pulse. This paper discusses this sparse breakdown in low-altitude wave propagation.

  2. Wiedenhfer et al. Inter-Organizational Crisis Management Infrastructure for Electrical Power Breakdowns

    E-Print Network [OSTI]

    .pipek}@uni-siegen.de ABSTRACT Major electricity breakdowns like the Northeast Blackout (USA) in 2003 or the blackout in most on electricity, as was the case in 2003 in the Northeast Blackout, USA, or 2005 in Western Europe (Lorenz, 2010Wiedenhöfer et al. Inter-Organizational Crisis Management Infrastructure for Electrical Power

  3. Plug flow and the breakdown of Bagnold scaling in cohesive granular flows Robert Brewster,1

    E-Print Network [OSTI]

    Levine, Alex J.

    Plug flow and the breakdown of Bagnold scaling in cohesive granular flows Robert Brewster,1 Gary S Cohesive granular media flowing down an inclined plane are studied by discrete element simulations. Previous work on cohesionless granular media demonstrated that within the steady flow regime where gravi

  4. Some three-dimensional problems related to dielectric breakdown and polycrystal plasticity

    E-Print Network [OSTI]

    Some three-dimensional problems related to dielectric breakdown and polycrystal plasticity Adriana estimate which scales differently when the yield set of the basic crystal is highly eccentric. For 3D. In both settings the Sachs bound is optimal. 1 Introduction The analysis of rigid, perfectly-plastic

  5. Breakdown of 2mm symmetry in electron diffraction from multiwalled carbon nanotubes

    E-Print Network [OSTI]

    Qin, Lu-Chang

    Breakdown of 2mm symmetry in electron diffraction from multiwalled carbon nanotubes Zejian Liu of single-walled carbon nanotubes always have 2mm symmetry regardless if the nanotubes them- selves have such symmetry. We here show that, for the case of multiwalled carbon nanotubes, the 2mm symmetry can break down

  6. Leakage current and dielectric breakdown behavior in annealed SiO2 aerogel films

    E-Print Network [OSTI]

    Jo, Moon-Ho

    Leakage current and dielectric breakdown behavior in annealed SiO2 aerogel films Moon-Ho Jo behavior in annealed SiO2 aerogel films for intermetal dielectric applications was investigated in a metal­insulator­semiconductor structure. SiO2 aerogel films with porosities of 70% exhibited Poole­Frenkel conduction both before

  7. Optical breakdown in transparent media with adjustable axial length and location

    E-Print Network [OSTI]

    Palanker, Daniel

    Optical breakdown in transparent media with adjustable axial length and location Ilya Toytman,1 of transparent materials. It might be useful for ophthalmic surgical applications including cataract surgery­430 (2006). 10. O. Brzobohatý, T. Cizmár, and P. Zemánek, "High quality quasi-Bessel beam generated by round

  8. Laser-induced fluorescence measurements of NCN in low-pressure CH{sub 4}/O{sub 2}/N{sub 2} flames and its role in prompt NO formation

    SciTech Connect (OSTI)

    Sutton, Jeffrey A.; Williams, Bradley A.; Fleming, James W. [Navy Technology Center for Safety and Survivability, Chemistry Division, Combustion Dynamics Section, Code 6185, Naval Research Laboratory, Washington, DC 20375-5342 (United States)

    2008-05-15

    NCN profiles were measured for five rich and lean premixed, low-pressure methane flames using laser-induced fluorescence (LIF). A semiquantitative determination of the NCN mole fractions as a function of spatial height above the burner is made by calibrating the NCN LIF signals using highly accurate OH LIF measurements in an adjacent spectral region. The resulting calibration yields an uncertainty estimate of a factor of 3 for the absolute values, but only {+-}25% for the relative NCN profiles. For all flame conditions, the NCN profiles occur immediately downstream of previously measured CH profiles. In addition, high correlations are found between the peak CH and peak NCN concentrations and the peak NCN and postflame NO concentrations over all equivalence ratios. These observations are consistent with NCN being the primary product channel from the CH + N{sub 2} reaction and the initial intermediate in the prompt NO formation. This is the first mechanistic study in hydrocarbon flames that provides such experimental evidence. The experimental profiles are compared to numerical calculations using modified versions of two well-established hydrocarbon kinetic mechanisms. Reasonable agreement between the calculations and experiment is found for NCN profile shape, location of peak NCN concentrations, and absolute mole fractions. However, the dependence on stoichiometry of the peak NCN concentration is overestimated. Further work is required on NCN kinetics for modeling prompt NO in laminar premixed flames. (author)

  9. 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.}

  10. 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 site. They are often marked by vacuum bursts and an increase in power reflected from the structure. The usual cause for NDB's during processing is the ''explosion'' of field emitters at sharp geometrical features on the metal surface. Exposed impurities in the metal surface can also produce NDB's as they are ''burned'' off by H-field heating or explosive field emission. The breakdown process can be roughly divided into four stages: (1) the formation of ''plasma spots'' at field emission sites, each spot leaving a crater-like footprint; (2) crater clustering, and the formation of areas with hundreds of overlapping craters; (3) surface melting in the region of a crater cluster; (4) the process after surface melting that leads to destructive breakdown.

  11. Investigating the effective range of vacuum ultraviolet-mediated breakdown in high-power microwave metamaterials

    SciTech Connect (OSTI)

    Liu, Chien-Hao, E-mail: cliu82@wisc.edu; Neher, Joel D., E-mail: jdneher@wisc.edu; Booske, John H., E-mail: booske@engr.wisc.edu; Behdad, Nader, E-mail: behdad@wisc.edu [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706 (United States)

    2014-10-14

    Metamaterials and periodic structures operating under high-power excitations are susceptible to breakdown. It was recently demonstrated that a localized breakdown created in a given region of a periodic structure can facilitate breakdown in other regions of the structure where the intensity of the incident electromagnetic fields may not be high enough to cause breakdown under normal circumstances. It was also demonstrated that this phenomenon is due to the generation of vacuum ultraviolet radiation at the location of the initial discharge, which propagates to the neighboring regions (e.g., other unit cells in a periodic structure) and facilitates the generation of a discharge at a lower incident power level. In this paper, we present the results of an experimental study conducted to determine the effective range of this physical phenomenon for periodic structures that operate in air and in pure nitrogen gas at atmospheric pressure levels. It is demonstrated that when breakdown is induced in a periodic structure using a high-power pulse with a frequency of 9.382 GHz, duration of 0.8 ?s, and peak power level of 25 kW, this phenomenon is highly likely to happen in radii of approximately 16–17 mm from the location of the initial discharge under these test conditions. The results of this study are significant in designing metamaterials and periodic structures for high-power microwave applications as they suggest that a localized discharge created in such a periodic structure with a periodicity less than 16–17 mm can spread over a large surface and result in a distributed discharge.

  12. ELECTRON PARAMAGNETIC RESONANCE SPECTROSCOPY

    E-Print Network [OSTI]

    Crofts, Antony R.

    . Excellent textbooks in EPR spectroscopy cover basic materials [2­5]. Many monographs are devoted to the consideration of more specific topics including theory, instrumentation, or application to selected paramagnetic species [6­19]. Handbooks of EPR spectroscopy [20, 21] are also available, as are periodic reviews

  13. Effect of Bubbles on Liquid Nitrogen Breakdown in Plane-Plane Electrode Geometry From 100-250 kPa

    SciTech Connect (OSTI)

    Sauers, Isidor [ORNL; James, David Randy [ORNL; Tuncer, Enis [ORNL; Polyzos, Georgios [ORNL; Pace, Marshall O [ORNL

    2011-01-01

    Liquid nitrogen (LN(2)) is used as the cryogen and dielectric for many high temperature superconducting, high voltage applications. When a quench in the superconductor occurs, bubbles are generated which can affect the dielectric breakdown properties of the LN(2). Experiments were performed using plane-plane electrode geometry where bubbles were introduced into the gap through a pinhole in the ground electrode. Bubbles were generated using one or more kapton heaters producing heater powers up to 30 W. Pressure was varied from 100-250 kPa. Breakdown strength was found to be relatively constant up to a given heater power and pressure at which the breakdown strength drops to a low value depending on the pressure. After the drop the breakdown strength continues to drop gradually at higher heater power. This is particularly illustrated at 100 kPa. After the drop in breakdown strength the breakdown is believed to be due to the formation of a vapor bridge. Also the heater power at which the breakdown strength changes from that of LN(2) to that of gaseous nitrogen increases with increasing pressure. The data can provide design constraints for high temperature superconducting fault current limiters (FCLs) so that the formation of a vapor bridge can be suppressed or avoided.

  14. 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.

  15. Effect of magnetic field on breakdown voltage characteristics of a multigap pseudospark

    SciTech Connect (OSTI)

    Sriram, D.; Jain, K.K. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)] [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

    1997-06-01

    An experimental investigation of the effect of magnetic field on the breakdown voltage characteristics of a multigap pseudospark device, with hydrogen gas, in a hollow anode{endash}cathode, as well as a hollow cathode{endash}anode configuration, is presented. The breakdown pressure at a particular discharge voltage increases with the increase in the applied axial magnetic field, and the magnitude of the increase is more pronounced at lower discharge voltages causing a right shift to the characteristic discharge curve in both the configurations. Application of a transverse magnetic field also resulted in a shift of the characteristic discharge curve towards the right. The observed results are compared and discussed with that found for parallel electrode geometry. {copyright} {ital 1997 American Institute of Physics.}

  16. Application of dynamic displacement current for diagnostics of subnanosecond breakdowns in an inhomogeneous electric field

    SciTech Connect (OSTI)

    Shao Tao; Zhang Cheng; Yan Ping [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Power Electronics and Electric Drive, Chinese Academy of Sciences, Beijing 100190 (China); Tarasenko, Victor F.; Burachenko, Alexandr G.; Rybka, Dmitry V.; Kostyrya, Igor' D.; Lomaev, Mikhail I.; Baksht, Evgeni Kh. [Institute of High Current Electronics, Russian Academy of Sciences, Tomsk 634055 (Russian Federation)

    2013-05-15

    The breakdown of different air gaps at high overvoltages in an inhomogeneous electric field was investigated with a time resolution of up to 100 ps. Dynamic displacement current was used for diagnostics of ionization processes between the ionization wave front and a plane anode. It is demonstrated that during the generation of a supershort avalanche electron beam (SAEB) with amplitudes of {approx}10 A and more, conductivity in the air gaps at the breakdown stage is ensured by the ionization wave, whose front propagates from the electrode of small curvature radius, and by the dynamic displacement current between the ionization wave front and the plane electrode. The amplitude of the dynamic displacement current measured by a current shunt is 100 times greater than the SAEB. It is shown that with small gaps and with a large cathode diameter, the amplitude of the dynamic displacement current during a subnanosecond rise time of applied pulse voltage can be higher than 4 kA.

  17. Electroneutrality Breakdown and Specific Ion Effects in Nanoconfined Aqueous Electrolytes Observed by NMR

    E-Print Network [OSTI]

    Zhi-Xiang Luo; Yun-Zhao Xing; Yan-Chun Ling; Alfred Kleinhammes; Yue Wu

    2015-02-24

    Ion distribution in aqueous electrolytes near the interface plays critical roles in electrochemical, biological and colloidal systems and is expected to be particularly significant inside nanoconfined regions. Electroneutrality of the total charge inside nanoconfined regions is commonly assumed a priori in solving ion distribution of aqueous electrolytes nanoconfined by uncharged hydrophobic surfaces with no direct experimental validation. Here, we use a quantitative nuclear magnetic resonance approach to investigate the properties of aqueous electrolytes nanoconfined in graphitic-like nanoporous carbon. Substantial electroneutrality breakdown in nanoconfined regions and very asymmetric responses of cations and anions to the charging of nanoconfining surfaces are observed. The electroneutrality breakdown is shown to depend strongly on the propensity of anions toward the water-carbon interface and such ion-specific response follows generally the anion ranking of the Hofmeister series. The experimental observations are further supported by numerical evaluation using the generalized Poisson-Boltzmann equation

  18. Rescaling of microwave breakdown theory for monatomic gases by particle-in-cell/Monte Carlo simulations

    SciTech Connect (OSTI)

    Wang, Huihui; Meng, Lin; Liu, Dagang; Liu, Laqun [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)] [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2013-12-15

    A particle-in-cell/Monte Carlo code is developed to rescale the microwave breakdown theory which is put forward by Vyskrebentsev and Raizer. The results of simulations show that there is a distinct error in this theory when the high energy tail of electron energy distribution function increases. A rescaling factor is proposed to modify this theory, and the change rule of the rescaling factor is presented.

  19. Toward pure electronic spectroscopy

    E-Print Network [OSTI]

    Petrovi?, Vladimir, 1978-

    2009-01-01

    In this thesis is summarized the progress toward completing our understanding of the Rydberg system of CaF and developing Pure Electronic Spectroscopy. The Rydberg system of CaF possesses a paradigmatic character due to ...

  20. Pulsed Zeeman spectroscopy 

    E-Print Network [OSTI]

    Cullen, Raymond Paul

    1967-01-01

    PULSED ZEEMAN SPECTROSCOPY A Thesis Raymond P. Cullen Submitted to the Graduate Collepe of the Texas MM University in partial fulfillment of the requirements for the degree of MASTER OE SCIENCE August 1967 Major Subject: Chemistry PULSRD... ZEEHA&'I SPRCTPOSC::)Py A The. ", is by Raymond P. Cullen Approved es to style and content by: (Chairman o~ Commi. tee) August 1967 Pulsed Zceman Spectroscopy (August 1967) Raymond P. Cullen, B. S. , Texas A6M University Directed by: Dr...

  1. 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.

  2. Radioiodine detector based on laser induced fluorescence

    DOE Patents [OSTI]

    McDonald, Jimmie R. (Upper Marlboro, MD); Baronavski, Andrew P. (Alexandria, VA)

    1980-01-01

    The invention involves the measurement of the concentration of the radioisotope .sup.129 I.sub.2 in the presence of a gas. The invention uses a laser to excite a sample of the .sup.129 I.sub.2 in a sample gas chamber and a reference sample of a known concentration of .sup.129 I.sub.2 in a reference gas chamber. The .sup.129 I.sub.2 in the sample and reference gas chamber each gives off fluorescence emissions which are received by photomultipliers which provide signals to a detector. The detector uses a ratioing technique to determine the concentration of .sup.129 I.sub.2 in the sample gas chamber.

  3. Nuclear reactivity control using laser induced polarization

    DOE Patents [OSTI]

    Bowman, Charles D. (Los Alamos, NM)

    1990-01-01

    A control element for reactivity control of a fission source provides an atomic density of .sup.3 He in a control volume which is effective to control criticality as the .sup.3 He is spin-polarized. Spin-polarization of the .sup.3 He affects the cross section of the control volume for fission neturons and hence, the reactivity. An irradiation source is directed within the .sup.3 He for spin-polarizing the .sup.3 He. An alkali-metal vapor may be included with the .sup.3 He where a laser spin-polarizes the alkali-metal atoms which in turn, spin-couple with .sup.3 He to spin-polarize the .sup.3 He atoms.

  4. Nuclear reactivity control using laser induced polarization

    DOE Patents [OSTI]

    Bowman, Charles D. (Los Alamos, NM)

    1991-01-01

    A control element for reactivity control of a fission source provides an atomic density of .sup.3 He in a control volume which is effective to control criticality as the .sup.3 He is spin-polarized. Spin-polarization of the .sup.3 He affects the cross section of the control volume for fission neutrons and hence, the reactivity. An irradiation source is directed within the .sup.3 He for spin-polarizing the .sup.3 He. An alkali-metal vapor may be included with the .sup.3 He where a laser spin-polarizes the alkali-metal atoms which in turn, spin-couple with .sup.3 He to spin-polarize the .sup.3 He atoms.

  5. Laser induced ponderomotive convection in water

    E-Print Network [OSTI]

    Shneider, M N

    2015-01-01

    A new mechanism for inducing convection during IR laser interaction with water or any absorbing polar liquid is described theoretically. The numerical simulations performed using the developed model show that the ponderomotive force produces water flow in the direction of the laser beam propagation. In the later stage of interaction, when water temperature rises, the Archimedes force becomes first comparable and then dominant producing convection directed against the vector of gravitational acceleration (upward). The theoretical estimates and the numerical simulations predict fluid dynamics that is similar to the observed in the previous experiments.

  6. Sandia Energy - Laser-Induced Fluorescence

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation of Fe(II)Geothermal Energy &Water Power ProgramLarge Eddy

  7. Spectroscopy of semiconductor materials

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque|SensitiveApril 2, 2014 SmithSpectroscopy ofSpectroscopy ofAg 3 VO

  8. 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.

  9. 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.

  10. DIFFUSING ACOUSTIC WAVE SPECTROSCOPY: FIELD FLUCTUATION SPECTROSCOPY WITH MULTIPLY

    E-Print Network [OSTI]

    Page, John

    DIFFUSING ACOUSTIC WAVE SPECTROSCOPY: FIELD FLUCTUATION SPECTROSCOPY WITH MULTIPLY SCATTERED Martyrs, B.P. 166, 38042 Grenoble Cedex 9, France Abstract. Diffusing Acoustic Wave Spectroscopy (DAWS that acoustic waves, and ultrasonic waves in particular, are playing in understanding the rich diversity of wave

  11. Supplemental Discussion Infrared spectroscopy

    E-Print Network [OSTI]

    Brown, Michael E.

    Supplemental Discussion Infrared spectroscopy We obtained near infrared reflectance spectra of 26 /~160 (see Supplemental Figure 1). The region between 1.81 and 1.89 µm has residual contamination the 50 Myr time period (see Supplemental Figure 2). doi: 10.1038/nature05619 SUPPLEMENTARY INFORMATION

  12. Pre-breakdown cavitation development in the dielectric fluid in the inhomogeneous, pulsed electric fields

    E-Print Network [OSTI]

    Mikhail N. Shneider; Mikhail Pekker

    2014-12-01

    We consider the development of pre-breakdown cavitation nanopores appearing in the dielectric fluid under the influence of the electrostrictive stresses in the inhomogeneous pulsed electric field. It is shown that three characteristic regions can be distinguished near the needle electrode. In the first region, where the electric field gradient is greatest, the cavitation nanopores, occurring during the voltage nanosecond pulse, may grow to the size at which an electron accelerated by the field inside the pores can acquire enough energy for excitation and ionization of the liquid on the opposite pore wall, i.e., the breakdown conditions are satisfied. In the second region, the negative pressure caused by the electrostriction is large enough for the cavitation initiation (which can be registered by optical methods), but, during the voltage pulse, the pores do not reach the size at which the potential difference across their borders becomes sufficient for ionization or excitation of water molecules. And, in the third, the development of cavitation is impossible, due to an insufficient level of the negative pressure: in this area, the spontaneously occurring micropores do not grow and collapse under the influence of surface tension forces. This paper discusses the expansion dynamics of the cavitation pores and their most probable shape.

  13. 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.

  14. 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.

  15. 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.

  16. String-theoretic breakdown of effective field theory near black hole horizons

    E-Print Network [OSTI]

    Dodelson, Matthew

    2015-01-01

    We investigate the validity of the equivalence principle near horizons in string theory, analyzing the breakdown of effective field theory caused by longitudinal string spreading effects. An experiment is set up where a detector is thrown into a black hole a long time after an early infalling string. Light cone gauge calculations, taken at face value, indicate a detectable level of root-mean-square longitudinal spreading of the initial string as measured by the late infaller. This results from the large relative boost between the string and detector in the near horizon region, which develops automatically despite their modest initial energies outside the black hole and the weak curvature in the geometry. We subject this scenario to basic consistency checks, using these to obtain a relatively conservative criterion for its detectability. In a companion paper, we exhibit longitudinal nonlocality in well-defined gauge-invariant S-matrix calculations, obtaining results consistent with the predicted spreading albe...

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

    SciTech Connect (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.

  18. Breakdown of metastable political duopoly due to asymmetry of emotions in partisan propaganda

    E-Print Network [OSTI]

    Sobkowicz, Pawel

    2015-01-01

    We present results of opinion dynamics simulations based on the emotion/information/opinion (E/I/O) model, applied to a strongly polarized society. Under certain conditions the model leads to metastable coexistence of two subcommunities (supporting each of the opinions) of comparable size -- which corresponds to bipartisan split found in many real world communities. Spurred by the recent breakdown of such system, which existed in Poland for over 9 years, we extend the model by allowing a third opinion. We show that if the propaganda messages of the two incumbent parties differ in emotional tone, the system may be "invaded" by a newcomer third party very quickly -- in qualitative agreement with the actual political situation in Poland in 2015.

  19. Experimental Demonstration of Effective Medium Approximation Breakdown in Deeply Subwavelength All-Dielectric Multilayers

    E-Print Network [OSTI]

    Zhukovsky, Sergei V; Takayama, Osamu; Shkondin, Evgeniy; Malureanu, Radu; Jensen, Flemming; Lavrinenko, Andrei V

    2015-01-01

    We experimentally demonstrate the effect of anomalous breakdown of the effective medium approximation in all-dielectric deeply subwavelength thickness ($d \\sim\\lambda/160-\\lambda/30$) multilayers, as recently predicted theoretically [H.H. Sheinfux et al., Phys. Rev. Lett. 113, 243901 (2014)]. Multilayer stacks are composed of alternating alumina and titania layers fabricated using atomic layer deposition. For light incident on such multilayers at angles near the total internal reflection we observe pronounced differences in the reflectance spectra for structures with 10-nm versus 20-nm thick layers, as well as for structures with different layers ordering, contrary to the predictions of the effective medium approximation. The reflectance difference can reach values up to 0.5, owing to the chosen geometrical configuration with an additional resonator layer employed for the enhancement of the effect. Our results are important for the development of new high-precision multilayer ellipsometry methods and schemes,...

  20. Magnetic breakdown and Landau level spectra of a tunable double-quantum-well Fermi surface

    SciTech Connect (OSTI)

    Simmons, J.A.; Harff, N.E.; Lyo, S.K.; Klem, J.F. [Sandia National Labs., Albuquerque, NM (United States); Boebinger, G.S.; Pfeiffer, L.N.; West, K.W. [Lucent Technologies, Murray Hill, NJ (United States). Bell Labs.

    1997-12-31

    By measuring longitudinal resistance, the authors map the Landau level spectra of double quantum wells as a function of both parallel (B{sub {parallel}}) and perpendicular (B{sub {perpendicular}}) magnetic fields. In this continuously tunable highly non-parabolic system, the cyclotron masses of the two Fermi surface orbits change in opposite directions with B{sub {parallel}}. This causes the two corresponding ladders of Landau levels formed at finite B{sub {perpendicular}} to exhibit multiple crossings. They also observe a third set of landau levels, independent of B{sub {parallel}}, which arise from magnetic breakdown of the Fermi surface. Both semiclassical and full quantum mechanical calculations show good agreement with the data.

  1. Evolution of the electron energy distribution function during genesis of breakdown plasma

    SciTech Connect (OSTI)

    Bhattacharjee, Sudeep; Paul, Samit; Ghosh, Sayandip [Department of Physics, Indian Institute of Technology – Kanpur, Kanpur 208016 (India)

    2014-08-15

    During the process of plasma initiation by an electromagnetic wave, it is found that the electron energy distribution function (EEDF) that is initially Maxwellian with the most probable energy at room temperature, evolves with time and tends toward a Bi-Maxwellian?–?indicating attainment of thermodynamic equilibrium in the individual electron populations prior to breakdown, with a significant increase in hot electron density. In the intermediate states during the evolution, however, non-equilibrium processes are prevalent under fast pulse excitation and the EEDF initially exhibits substantial deviation from a Maxwellian. An analysis of the deviation has been carried out by optimizing the residual sum of squares of the probabilities obtained from the simulation and a fitted Maxwellian curve. The equilibrium regain time defined as the time required to attain thermodynamic equilibrium again, is investigated as a function of neutral pressure, wave electric, and external magnetostatic fields.

  2. Grain-scale thermoelastic stresses and spatiotemporal temperature gradients on airless bodies, implications for rock breakdown

    E-Print Network [OSTI]

    Molaro, Jamie L; Langer, Steve A

    2015-01-01

    Thermomechanical processes such as fatigue and shock have been suggested to cause and contribute to rock breakdown on Earth, and on other planetary bodies, particularly airless bodies in the inner solar system. In this study, we modeled grain-scale stresses induced by diurnal temperature variations on simple microstructures made of pyroxene and plagioclase on various solar system bodies. We found that a heterogeneous microstructure on the Moon experiences peak tensile stresses on the order of 100 MPa. The stresses induced are controlled by the coefficient of thermal expansion and Young's modulus of the mineral constituents, and the average stress within the microstructure is determined by relative volume of each mineral. Amplification of stresses occurs at surface-parallel boundaries between adjacent mineral grains and at the tips of pore spaces. We also found that microscopic spatial and temporal surface temperature gradients do not correlate with high stresses, making them inappropriate proxies for investig...

  3. Extreme seasonality of litter breakdown in an arctic spring-fed stream is driven by shredder phenology, not

    E-Print Network [OSTI]

    Benstead, Jon

    regimes. We used an alternative approach to investigate the importance of temperature by quantifying seasonal patterns in litter breakdown in an arctic spring-fed stream (Ivishak Spring, North Slope, Alaska) that experiences extreme seasonality in light availability and energy inputs while fluctuations in water

  4. 518 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 33, NO. 2, APRIL 2005 Plasma Dynamics During Breakdown in

    E-Print Network [OSTI]

    Kushner, Mark

    , lamp, modeling, plasma. METAL halide arc lamps are widely used sources of in- door and large area518 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 33, NO. 2, APRIL 2005 Plasma Dynamics During plasma hydrodynamics model was used to investigate breakdown in metal halide lamp. Images depicting

  5. Electrical and Sensing Properties of Single-Walled Carbon Nanotubes Network: Effect of Alignment and Selective Breakdown

    E-Print Network [OSTI]

    Full Paper Electrical and Sensing Properties of Single-Walled Carbon Nanotubes Network: Effect The electrical transport and NH3 sensing properties of randomly oriented and aligned SWNT networks were presented. Gated electrical breakdown was implemented to selectively remove metallic (m-) SWNTs, thereby reducing

  6. `I'll just pass you to Customer Service...' Communication Breakdown Between the Users and Suppliers of Clinical Technology

    E-Print Network [OSTI]

    Johnson, Chris

    `I'll just pass you to Customer Service...' Communication Breakdown Between the Users and Suppliers and suppliers. Recent mishaps have shown that clinicians may not know whether a device has actually from suppliers who may not have been directly responsible for the development of the device

  7. Method of Controlling Corona Effects and Breakdown Voltage of Small Air Gaps Stressed by Impulse Voltages

    E-Print Network [OSTI]

    Athanasios Maglaras; Trifon Kousiouris; Frangiskos Topalis; Dimitrios Katsaros; Leandros A. Maglaras; Konstantina Giannakopoulou

    2014-10-15

    This paper investigates the influence of a resistor on the dielectric behavior of an air gap. The resistor is connected in series with the air gap and the latter is stressed by impulse voltage. Air gap arrangements of different geometry with either the rod or the plate grounded are stressed with impulse voltages of both positive and negative polarity. The resistor is connected in series with the air gap in the return circuit connecting the gap with the impulse generator. The method followed involves the investigation of the graphs of the charging time concerning the air gaps capacitances, in connection to the value of the resistor, the geometry of the gap, the effect of grounding and the polarity effect. It is determined that the charging time of the air gap increases, as the value of the resistor increases. It is also determined that the peak voltage value of the fully charged air gap decreases as the value of the resistor increases. The results of the mathematical and simulation analysis are compared with the results of the oscillograms taken from experimental work. In addition and consequently to the above results it is concluded from the experimental work that the in series connection of the resistor in the circuit has significant influence on corona pulses (partial discharges) occurring in the gap and on the breakdown voltage of the gap. A new method of controlling the corona effects and consequently the breakdown voltage of small air gaps stressed by impulse voltage of short duration in connection to the ground effect and the polarity effect has arisen. Furthermore through mathematical analysis of the charging graphs obtained from simulation and experimental oscillograms there was a calculation of the values of the capacitance of the air gaps in relation to their geometry and the results were compared to the values calculated with mathematical analysis.

  8. Spectroscopy of $^{26}$F

    E-Print Network [OSTI]

    Stanoiu, M; Sorlin, O; Dombradi, Zs; Azaiez, F; Brown, B A; Borcea, C; Bourgeois, C; Elekes, Z; Fülöp, Zs; Grévy, S; Guillemaud-Mueller, D; Ibrahim, F; Kerek, A; Krasznahorkay, A; Lewitowicz, M; Lukyanov, S M; Mrazek, J; Negoita, F; Penionzhkevich, Yu -E; Podolyak, Zs; Porquet, M G; Roussel-Chomaz, P; Saint-Laurent, M G; Savajols, H; Sletten, G; Timar, J; Timis, C

    2012-01-01

    The structure of the weakly-bound $^{26}_{\\;\\;9}$F$_{17}$ odd-odd nucleus, produced from $^{27,28}$Na nuclei, has been investigated at GANIL by means of the in-beam $\\gamma$-ray spectroscopy technique. A single $\\gamma$-line is observed at 657(7) keV in $^{26}_{9}$F which has been ascribed to the decay of the excited J=$2^+$ state to the J=1$^+$ ground state. The possible presence of intruder negative parity states in $^{26}$F is also discussed.

  9. Dark Matter Velocity Spectroscopy

    E-Print Network [OSTI]

    Eric G. Speckhard; Kenny C. Y. Ng; John F. Beacom; Ranjan Laha

    2015-07-31

    Dark matter decays or annihilations that produce line-like spectra may be smoking-gun signals. However, even such distinctive signatures can be mimicked by astrophysical or instrumental causes. We show that velocity spectroscopy-the measurement of energy shifts induced by relative motion of source and observer-can separate these three causes with minimal theoretical uncertainties. The principal obstacle has been energy resolution, but upcoming experiments will reach the required 0.1% level. As an example, we show that the imminent Astro-H mission can use Milky Way observations to separate possible causes of the 3.5-keV line. We discuss other applications.

  10. Automated Interpretation of LIBS Spectra using a Fuzzy Logic Inference Engine

    SciTech Connect (OSTI)

    Jeremy J. Hatch; Timothy R. McJunkin; Cynthia Hanson; Jill R. Scott

    2012-02-01

    Automated interpretation of laser-induced breakdown spectroscopy (LIBS) data is necessary due to the plethora of spectra that can be acquired in a relatively short time. However, traditional chemometric and artificial neural network methods that have been employed are not always transparent to a skilled user. A fuzzy logic approach to data interpretation has now been adapted to LIBS spectral interpretation. A fuzzy logic inference engine (FLIE) was used to differentiate between various copper containing and stainless steel alloys as well as unknowns. Results using FLIE indicate a high degree of confidence in spectral assignment.

  11. Quantitative analysis of tin alloy combined with artificial neural network prediction

    SciTech Connect (OSTI)

    Oh, Seong Y.; Yueh, Fang-Yu; Singh, Jagdish P.

    2010-05-01

    Laser-induced breakdown spectroscopy was applied to quantitative analysis of three impurities in Sn alloy. The impurities analysis was based on the internal standard method using the Sn I 333.062-nm line as the reference line to achieve the best reproducible results. Minor-element concentrations (Ag, Cu, Pb) in the alloy were comparatively evaluated by artificial neural networks (ANNs) and calibration curves. ANN was found to effectively predict elemental concentrations with a trend of nonlinear growth due to self-absorption. The limits of detection for Ag, Cu, and Pb in Sn alloy were determined to be 29, 197, and 213 ppm, respectively.

  12. Apparatus and method for quantitative determination of materials contained in fluids

    DOE Patents [OSTI]

    Radziemski, L.J.; Cremers, D.A.

    1982-09-07

    Apparatus and method for near real-time in-situ monitoring of particulates and vapors contained in fluids are described. Initial filtration of a known volume of the fluid sample is combined with laser-induced dielectric breakdown spectroscopy of the filter employed to obtain qualitative and quantitative information with high sensitivity. Application of the invention to monitoring of beryllium, beryllium oxide, or other beryllium-alloy dusts is shown. Significant shortening of analysis time is achieved from the usual chemical techniques of analysis.

  13. Dual fiber microprobe for mapping elemental distributions in biological cells

    DOE Patents [OSTI]

    Martin, Rodger C [Powell, TN; Martin, Madhavi Z [Powell, TN

    2007-07-31

    Laser-induced breakdown spectroscopy (LIBS) is applied on a microscale for in situ elemental analysis and spatial mapping in biological cells. A high power laser beam is focused onto a cell surface using a dual branching optical fiber probe for optical excitation of the cell constituents. Dual spectrometers and ICCD detectors capture the emission spectra from the excited cell(s). Repeated probing or repositioning of the laser beam with respect to the cell can provide 2-D or 3-D mapping of the cell.

  14. Apparatus and method for quantitative determination of materials contained in fluids

    DOE Patents [OSTI]

    Radziemski, Leon J. (Los Alamos, NM); Cremers, David A. (Los Alamos, NM)

    1985-01-01

    Apparatus and method for near real-time in-situ monitoring of particulates and vapors contained in fluids. Initial filtration of a known volume of the fluid sample is combined with laser-induced dielectric breakdown spectroscopy of the filter employed to obtain qualitative and quantitative information with high sensitivity. Application of the invention to monitoring of beryllium, beryllium oxide, or other beryllium-alloy dusts is demonstrated. Significant shortening of analysis time is achieved from those of the usual chemical techniques of analysis.

  15. Fourier Transform Infrared (FTIR) Spectroscopy

    E-Print Network [OSTI]

    Gerwert, Klaus

    Fourier Transform Infrared (FTIR) Spectroscopy Klaus Gerwert, Lehrstuhl fu¨r Biophysik, Ruhr, Germany Based in part on the previous version of this Encyclopedia of Life Sciences (ELS) article, Fourier Transform IR by Johannes Orphal. Fourier transform infrared (FTIR) spectroscopy is an experimental technique

  16. The light meson spectroscopy program

    SciTech Connect (OSTI)

    Smith, Elton S.

    2014-06-01

    Recent discoveries of a number of unexpected new charmomium-like meson states at the BaBar and Belle B-factories have demonstrated how little is still known about meson spectroscopy. In this talk we will review recent highlights of the light quark spectroscopy from collider and fixed target experiments.

  17. Time of flight emission spectroscopy of laser produced nickel plasma: Short-pulse and ultrafast excitations

    SciTech Connect (OSTI)

    Smijesh, N.; Chandrasekharan, K. [Laser and Nonlinear Optics Laboratory, Department of Physics, National Institute of Technology Calicut, Calicut 673601 (India); Joshi, Jagdish C.; Philip, Reji, E-mail: reji@rri.res.in [Ultrafast and Nonlinear Optics Lab, Light and Matter Physics Group, Raman Research Institute, Bangalore 560080 (India)

    2014-07-07

    We report the experimental investigation and comparison of the temporal features of short-pulse (7 ns) and ultrafast (100 fs) laser produced plasmas generated from a solid nickel target, expanding into a nitrogen background. When the ambient pressure is varied in a large range of 10??Torr to 10²Torr, the plume intensity is found to increase rapidly as the pressure crosses 1 Torr. Time of flight (TOF) spectroscopy of emission from neutral nickel (Ni I) at 361.9 nm (3d?(²D) 4p ? 3d?(²D) 4s transition) reveals two peaks (fast and slow species) in short-pulse excitation and a single peak in ultrafast excitation. The fast and slow peaks represent recombined neutrals and un-ionized neutrals, respectively. TOF emission from singly ionized nickel (Ni II) studied using the 428.5 nm (3p?3d?(³P) 4s? 3p?3d? 4s) transition shows only a single peak for either excitation. Velocities of the neutral and ionic species are determined from TOF measurements carried out at different positions (i.e., at distances of 2 mm and 4 mm, respectively, from the target surface) on the plume axis. Measured velocities indicate acceleration of neutrals and ions, which is caused by the Coulomb pull of the electrons enveloping the plume front in the case of ultrafast excitation. Both Coulomb pull and laser-plasma interaction contribute to the acceleration in the case of short-pulse excitation. These investigations provide new information on the pressure dependent temporal behavior of nickel plasmas produced by short-pulse and ultrafast laser pulses, which have potential uses in applications such as pulsed laser deposition and laser-induced nanoparticle generation.

  18. Protected subspace Ramsey spectroscopy

    E-Print Network [OSTI]

    Laurin Ostermann; David Plankensteiner; Helmut Ritsch; Claudiu Genes

    2014-11-27

    We study a modified Ramsey spectroscopy technique employing slowly decaying states for quantum metrology applications using dense ensembles. While closely positioned atoms exhibit superradiant collective decay and dipole-dipole induced frequency shifts, recent results [Ostermann, Ritsch and Genes, Phys. Rev. Lett. \\textbf{111}, 123601 (2013)] suggest the possibility to suppress such detrimental effects and achieve an even better scaling of the frequency sensitivity with interrogation time than for noninteracting particles. Here we present an in-depth analysis of this 'protected subspace Ramsey technique' using improved analytical modeling and numerical simulations including larger 3D samples. Surprisingly we find that using sub-radiant states of $N$ particles to encode the atomic coherence yields a scaling of the optimal sensitivity better than $1/\\sqrt{N}$. Applied to ultracold atoms in 3D optical lattices we predict a precision beyond the single atom linewidth.

  19. On the breakdown of perturbative integrability in large N matrix models

    E-Print Network [OSTI]

    Thomas Klose

    2005-07-21

    We study the perturbative integrability of the planar sector of a massive SU(N) matrix quantum mechanical theory with global SO(6) invariance and Yang-Mills-like interaction. This model arises as a consistent truncation of maximally supersymmetric Yang-Mills theory on a three-sphere to the lowest modes of the scalar fields. In fact, our studies mimic the current investigations concerning the integrability properties of this gauge theory. Like in the field theory we can prove the planar integrability of the SO(6) model at first perturbative order. At higher orders we restrict ourselves to the widely studied SU(2) subsector spanned by two complexified scalar fields of the theory. We show that our toy model satisfies all commonly studied integrability requirements such as degeneracies in the spectrum, existence of conserved charges and factorized scattering up to third perturbative order. These are the same qualitative features as the ones found in super Yang-Mills theory, which were enough to conjecture the all-loop integrability of that theory. For the SO(6) model, however, we show that these properties are not sufficient to predict higher loop integrability. In fact, we explicitly demonstrate the breakdown of perturbative integrability at fourth order.

  20. Optical, radio and x-ray radiation of red sprites produced by runaway air breakdown

    SciTech Connect (OSTI)

    Yukhimuk, V.; Roussel-Dupre, R.; Symbalisty, E.; Taranenko, Y.

    1997-04-01

    The authors use the runaway air breakdown model of upward discharges to calculate optical, radio, and X-ray radiation generated by red sprites. Red sprites are high altitude (up to 90 km) lightning discharges. Aircraft based observations show that sprites are predominantly red in color at altitudes above {approximately}55 km with faint blue tendrils, which extend downward to an altitude of 40 km; the duration of a single sprite is less than 17 ms, their maximum brightness is about 600 kR, and estimated total optical energy is about 1--5 kJ per event. The ground based observations show similar results, and provide some additional information on spatial and temporal structure of sprites, and on sprite locations. One difference between aircraft and ground-based observations is that blue tendrils are rarely observed from the ground. Sprites usually occur above the anvils of large mesoscale convective systems and correlate with strong positive cloud to ground discharge. Upward discharges are the most probable source of X-ray emission observed above large thunderstorm complexes by the Compton Gamma-ray Observatory. To escape the atmosphere these {gamma}-rays must originate above 25 km altitude. Red sprites are usually observed at altitudes higher than 50 km, and are therefore a likely source of this x-ray emission.

  1. IEEE TRANSACTIONS ON DEVICE AND MATERIALS RELIABILITY, VOL. 5, NO. 2, JUNE 2005 231 Hydrogen-Induced Changes in the Breakdown

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    -Induced Changes in the Breakdown Voltage of InP HEMTs Roxann R. Blanchard, Jesús A. del Alamo, and Albert Cornet Alamo is with the Massachusetts Institute of Technology, Cam- bridge, MA 02139 USA (e-mail: alamo

  2. New and Emerging Technologies for Real-Time Air and Surface Beryllium Monitoring

    SciTech Connect (OSTI)

    Phifer, B.E. Jr.; Churnetski, E.L.; Cooke, L.E.; Reed, J.J.; Howell, M.L.; Smith, V.D.

    2001-09-01

    In this study, five emerging technologies were identified for real-time monitoring of airborne beryllium: Microwave-Induced Plasma Spectroscopy (MIPS), Aerosol Beam-Focused Laser-Induced Plasma Spectroscopy (ABFLIPS), Laser-Induced Breakdown Spectroscopy (LIBS), Surfaced-Enhanced Raman Scattering (SERS) Spectroscopy, and Micro-Calorimetric Spectroscopy (CalSpec). Desired features of real-time air beryllium monitoring instrumentation were developed from the Y-12 CBDPP. These features were used as guidelines for the identification of potential technologies as well as their unique demonstrated capability to provide real-time monitoring of similar materials. However, best available technologies were considered, regardless of their ability to comply with the desired features. None of the five technologies have the capability to measure the particle size of airborne beryllium. Although reducing the total concentration of airborne beryllium is important, current literature suggests that reducing or eliminating the concentration of respirable beryllium is critical for worker health protection. Eight emerging technologies were identified for surface monitoring of beryllium. CalSpec, MIPS, SERS, LIBS, Laser Ablation, Absorptive Stripping Voltametry (ASV), Modified Inductively Coupled Plasma (ICP) Spectroscopy, and Gamma BeAST. Desired features of real-time surface beryllium monitoring were developed from the Y-12 CBDPP. These features were used as guidelines for the identification of potential technologies. However, the best available technologies were considered regardless of their ability to comply with the desired features.

  3. Measurements of the volt-ampere characteristics and the breakdown voltages of direct-current helium and hydrogen discharges in microgaps

    SciTech Connect (OSTI)

    Klas, M.; Matej?ik, Š.; Radjenovi?, B.; Radmilovi?-Radjenovi?, M.

    2014-10-15

    The discharge phenomena for micro meter gap sizes include many interesting problems from engineering and physical perspectives. In this paper, the authors deal with the experimental and theoretical results of the breakdown voltage and current-voltage characteristics of the direct-current helium and hydrogen discharges. The measurements were performed at a constant pressure of around one atmosphere, while varying the gap size between two parallel plane tungsten electrodes between 1??m and 100??m. From the measured breakdown voltage curves, the effective yields and the ionization coefficients were derived for both gases. Present data for the ionization coefficients correlate with the data obtained for the breakdown voltage curves measured for fixed 100??m interelectrode separation. The current-voltage characteristics were plotted for the various gap sizes illustrating the role of the field emission effects in the microgaps. Based on the Fowler-Nordheim theory, the enhancement factors were determined. The gap spacing dependence of the field emission current can be explained by the introduction of two ideas, the first being a space charge effect by emitted electrons, and the second a change in the breakdown mechanism. Experimental results, presented here, demonstrate that Townsend phenomenology breaks down when field emission becomes the key mechanism affecting the breakdown and deforming the left hand side of the breakdown voltage curves.

  4. Fiber Laser Based Nonlinear Spectroscopy

    E-Print Network [OSTI]

    Adany, Peter

    2012-08-31

    To date, nonlinear spectroscopy has been considered an expensive technique and confined mostly to experimental laboratory settings. Over recent years, optical-fiber lasers that are highly reliable, simple to operate and relatively inexpensive have...

  5. Ring resonant cavities for spectroscopy

    DOE Patents [OSTI]

    Zare, R.N.; Martin, J.; Paldus, B.A.; Xie, J.

    1999-06-15

    Ring-shaped resonant cavities for spectroscopy allow a reduction in optical feedback to the light source, and provide information on the interaction of both s- and p-polarized light with samples. A laser light source is locked to a single cavity mode. An intracavity acousto-optic modulator may be used to couple light into the cavity. The cavity geometry is particularly useful for Cavity Ring-Down Spectroscopy (CRDS). 6 figs.

  6. High spatial resolution mapping of deposition layers on plasma facing materials by laser ablation microprobe time-of-flight mass spectroscopy

    SciTech Connect (OSTI)

    Xiao, Qingmei; Li, Cong; Hai, Ran; Zhang, Lei; Feng, Chunlei; Ding, Hongbin, E-mail: hding@dlut.edu.cn [School of Physics and Optical Electronic Technology, Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Chinese Ministry of Education, Dalian University of Technology, Dalian 116024 (China); Zhou, Yan; Yan, Longwen; Duan, Xuru [Southwestern Institute of Physics, P.O. Box 432, No. 3 South Section 3, Circle Road 2, Chengdu 610041, Sichuan (China)

    2014-05-15

    A laser ablation microprobe time-of-flight mass spectroscopy (LAM-TOF-MS) system with high spatial resolution, ?20 nm in depth and ?500 ?m or better on the surface, is developed to analyze the composition distributions of deposition layers on the first wall materials or first mirrors in tokamak. The LAM-TOF-MS system consists of a laser ablation microprobe combined with a TOF-MS and a data acquisition system based on a LabVIEW program software package. Laser induced ablation combined with TOF-MS is an attractive method to analyze the depth profile of deposited layer with successive laser shots, therefore, it can provide information for composition reconstruction of the plasma wall interaction process. In this work, we demonstrate that the LAM-TOF-MS system is capable of characterizing the depth profile as well as mapping 2D composition of deposited film on the molybdenum first mirror retrieved from HL-2A tokamak, with particular emphasis on some of the species produced during the ablation process. The presented LAM-TOF-MS system provides not only the 3D characterization of deposition but also the removal efficiency of species of concern.

  7. TIME-RESOLVED VIBRATIONAL SPECTROSCOPY

    SciTech Connect (OSTI)

    Andrei Tokmakoff, MIT; Paul Champion, Northeastern University; Edwin J. Heilweil, NIST; Keith A. Nelson, MIT; Larry Ziegler, Boston University

    2009-05-14

    This document contains the Proceedings from the 14th International Conference on Time-Resolved Vibrational Spectroscopy, which was held in Meredith, NH from May 9-14, 2009. The study of molecular dynamics in chemical reaction and biological processes using time-resolved spectroscopy plays an important role in our understanding of energy conversion, storage, and utilization problems. Fundamental studies of chemical reactivity, molecular rearrangements, and charge transport are broadly supported by the DOE�s Office of Science because of their role in the development of alternative energy sources, the understanding of biological energy conversion processes, the efficient utilization of existing energy resources, and the mitigation of reactive intermediates in radiation chemistry. In addition, time-resolved spectroscopy is central to all five of DOE�s grand challenges for fundamental energy science. The Time-Resolved Vibrational Spectroscopy conference is organized biennially to bring the leaders in this field from around the globe together with young scientists to discuss the most recent scientific and technological advances. The latest technology in ultrafast infrared, Raman, and terahertz spectroscopy and the scientific advances that these methods enable were covered. Particular emphasis was placed on new experimental methods used to probe molecular dynamics in liquids, solids, interfaces, nanostructured materials, and biomolecules.

  8. Near-critical phase explosion promoting breakdown plasma ignition during laser ablation of graphite

    SciTech Connect (OSTI)

    Ionin, A. A.; Kudryashov, S. I.; Seleznev, L. V. [P.N. Lebedev Physical Institute, Russian Academy of Sciences, 119991 Moscow (Russian Federation)

    2010-07-15

    Removal rate, air shock, and ablative recoil pressure parameters were measured as a function of laser intensity I{sub peak} during nanosecond laser ablation of graphite. Surface vaporization of molten graphite at low intensities I{sub peak}<0.15 GW/cm{sup 2} was observed to transform into its near-critical phase explosion (intense homogeneous boiling) at the threshold intensity I{sub PE}approx =0.15 GW/cm{sup 2} in the form of a drastic, correlated rise of removal rate, air shock, and ablative recoil pressure magnitudes. Just above this threshold (I{sub peak}>=0.25 GW/cm{sup 2}), the explosive mass removal ended up with saturation of the removal rate, much slower increase of the air and recoil pressure magnitudes, and appearance of a visible surface plasma spark. In this regime, the measured far-field air shock pressure amplitude exhibits a sublinear dependence on laser intensity (propor toI{sub peak}{sup 4/9}), while the source plasma shock pressure demonstrates a sublinear trend (propor toI{sub peak}{sup 3/4}), both indicating the subcritical character of the plasma. Against expectations, in this regime the plasma recoil pressure increases versus I{sub peak} superlinearly (propor toI{sub peak}{sup 1.1}), rather than sublinearly (propor toI{sub peak}{sup 3/4}), with the mentioned difference related to the intensity-dependent initial spatial plasma dimensions within the laser waist on the graphite surface and to the plasma formation time during the heating laser pulse (overall, the pressure source effect). The strict coincidence of the phase explosion, providing high (kbar) hydrodynamic pressures of ablation products, and the ignition of ablative laser plasma in the carbon plume may indicate the ablative pressure-dependent character of the underlying optical breakdown at the high plume pressures, initiating the plasma formation. The experimental data evidence that the spatiotemporal extension of the plasma in the laser plume and ambient air during the heating laser pulse is supported by fast lateral electron and radiative heat conduction (laser-supported combustion wave regime), rather than by propagation of a strong shock wave (laser-supported detonation wave regime).

  9. Diagnosing breast cancer using diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy

    E-Print Network [OSTI]

    Fitzmaurice, Maryann

    Using diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy, we have developed an algorithm that successfully classifies normal breast tissue, fibrocystic change, fibroadenoma, and infiltrating ductal ...

  10. The role of phase instabilities in the early material response...

    Office of Scientific and Technical Information (OSTI)

    The role of phase instabilities in the early material response during laser-induced breakdown in bulk fused silica Citation Details In-Document Search Title: The role of phase...

  11. Role of phase instabilities in the early response of bulk fused...

    Office of Scientific and Technical Information (OSTI)

    Role of phase instabilities in the early response of bulk fused silica during laser-induced breakdown Citation Details In-Document Search Title: Role of phase instabilities in the...

  12. The surface structure of ?-uranophane and its interaction with Eu(III) – An integrated computational and fluorescence spectroscopy study

    SciTech Connect (OSTI)

    Kuta, Jadwiga; Wang, Zheming; Wisuri, Katy; Wander, Matthew C F.; Wall, Nathalie; Clark, Aurora E.

    2013-02-15

    Uranophane is a rare U(VI) secondary silicate mineral formed in nature by the oxidation of the primary mineral uraninite. It is also relevant to the long-term geochemistry of nuclear waste repositories, where it can be formed under oxidizing conditions and has the potential to act as a secondary barrier to the migration of radionuclides through mineral sorption reactions. A combination of classical molecular dynamics and ab-initio density functional theory (DFT) has been employed to investigate the uranophane|water interface as well as the interfacial reactivity of the U(VI) silicate toward acidic conditions and radionuclide ion sorption. The sorption simulations have been complemented by experimental sorption studies and laser induced fluorescence spectroscopy to help identify the molecular structure of the surface sorbed species. Experimental distances and essential coordination numbers are properly captured by the simulation results within bulk uranophane, while interfacial water is found to orient primarily with the hydrogen-atoms directed towards the negatively charged surface. Sorption sites for water are observed to belong to 3 different groups: (1) those involving uranyl oxygen, (2) involving uranyl and silica hydroxyl oxygen atoms, and (3) involving hydroxyl hydrogen. The pKa of the surface -OH groups have been calculated using a variety of models, including a bond valence approach and utilization of the energetics of deprotonation within DFT. Under basic conditions, deprotonation of the Si-OH groups is likely responsible for uranophane dissolution. Finally, the stability and structure of surface sorbed Eu3+ has been examined, with a stable inner-sphere species being observed.

  13. A Roadmap For Meson Spectroscopy

    E-Print Network [OSTI]

    M. G. Olsson

    2002-07-31

    An efficient classification of light quark meson states is discussed based on the dominance of angular and radial quark excitation. A synthesis of Regge and quark dynamics allows a natural unification of light quark-antiquark spectroscopies and indicates the states that fall outside this category such as molecules, hybrids, and glueballs.

  14. High-spin nuclear spectroscopy

    SciTech Connect (OSTI)

    Diamond, R.M.

    1986-07-01

    High-spin spectroscopy is the study of the changes in nuclear structure, properties, and behavior with increasing angular momentum. It involves the complex interplay between collective and single-particle motion, between shape and deformation changes, particle alignments, and changes in the pairing correlations. A review of progress in theory, experimentation, and instrumentation in this field is given. (DWL)

  15. Thermal Lens Spectroscopy Mladen Franko

    E-Print Network [OSTI]

    Reid, Scott A.

    Thermal Lens Spectroscopy Mladen Franko Laboratory of Environmental Research, University of Nova-beam Instruments 5 3.3 Differential Thermal Lens Instruments 7 3.4 Multiwavelength and Tunable Thermal Lens Spectrometers 8 3.5 Circular Dichroism TLS Instruments 9 3.6 Miniaturization of Thermal Lens Instruments 9 4

  16. Ramsey spectroscopy with squeezed light

    E-Print Network [OSTI]

    Kenan Qu; G. S. Agarwal

    2013-07-12

    Traditional Ramsey spectroscopy has the frequency resolution $2\\pi/T$, where $T$ is the time separation between two light fields. Using squeezed states and two-atom excitation joint detection, we present a new scheme achieving a higher resolution $\\pi/T$. We use two mode squeezed light which exhibits strong entanglement.

  17. GUEST EDITORIAL Coherent Multidimensional Optical Spectroscopy

    E-Print Network [OSTI]

    Mukamel, Shaul

    motions offering dramatically more information. In 1D spectroscopy, the linear electrical polarization to the picosecond, electronically off-resonant, coher- ent anti-Stokes Raman spectroscopy (CARS) measurements of

  18. Electrochemistry, Photoelectrochemistry And Photoelectron Spectroscopy Of Nanostructured Metal Oxides

    E-Print Network [OSTI]

    Södergren, S

    1997-01-01

    Electrochemistry, Photoelectrochemistry And Photoelectron Spectroscopy Of Nanostructured Metal Oxides

  19. Anomalous ring-down effects and breakdown of the decay rate concept in optical cavities with negative group delay

    E-Print Network [OSTI]

    T. Lauprêtre; S. Schwartz; R. Ghosh; I. Carusotto; F. Goldfarb; F. Bretenaker

    2012-01-06

    Propagation of light pulses through negative group velocity media is known to give rise to a number of paradoxical situations that seem to violate causality. The solution of these paradoxes has triggered the investigation of a number of interesting and unexpected features of light propagation. Here we report a combined theoretical and experimental study of the ring-down oscillations in optical cavities filled with a medium with such a strongly negative frequency dispersion to give a negative round-trip group delay time. We theoretically anticipate that causality imposes the existence of additional resonance peaks in the cavity transmission, resulting in a non-exponential decay of the cavity field and in a breakdown of the cavity decay rate concept. Our predictions are validated by simulations and by an experiment using a room-temperature gas of metastable helium atoms in the detuned electromagnetically induced transparency regime as the cavity medium.

  20. The Passivity and Breakdown of Beryllium in Aqueous Solutions M.A. Hill, D.P. Butt, and R.S. Lillard

    E-Print Network [OSTI]

    The Passivity and Breakdown of Beryllium in Aqueous Solutions M.A. Hill, D.P. Butt, and R beryllium (Be) has been studied as a function of pH. Below pH 2, Be exhibited active dissolution at all, the presence of the fluoride increased the passive current density of beryllium, but had no effect

  1. Atmospheric pressure He-air plasma jet: Breakdown process and propagation phenomenon

    SciTech Connect (OSTI)

    Begum, Asma; Laroussi, Mounir; Pervez, Mohammad Rasel

    2013-06-15

    In this paper He-discharge (plasma jet/bullet) in atmospheric pressure air and its progression phenomenon has been studied experimentally using ICCD camera, optical emission spectroscopy (OES) and calibrated dielectric probe measurements. The repetitive nanosecond pulse has applied to a plasma pencil to generate discharge in the helium gas channel. The discharge propagation speed was measured from the ICCD images. The axial electric field distribution in the plasma jet is inferred from the optical emission spectroscopic data and from the probe measurement. The correlation between the jet velocities, jet length with the pulse duration is established. It shows that the plasma jet is not isolated from the input voltage along its propagation path. The discharge propagation speed, the electron density and the local and average electric field distribution along the plasma jet axis predicted from the experimental results are in good agreement with the data predicted by numerical simulation of the streamer propagation presented in different literatures. The ionization phenomenon of the discharge predicts the key ionization parameters, such as speed, peak electric field in the front, and electron density. The maximum local electric field measured by OES is 95 kV/cm at 1.3 cm of the jet axis, and average EF measured by probe is 24 kV/cm at the same place of the jet. The average and local electron density estimated are in the order of 10{sup 11} cm{sup -3} and it reaches to the maximum of 10{sup 12} cm{sup -3}.

  2. Final Report: Investigation of Catalytic Pathways for Lignin Breakdown into Monomers and Fuels

    SciTech Connect (OSTI)

    Gluckstein, Jeffrey A; Hu, Michael Z.; Kidder, Michelle; McFarlane, Joanna; Narula, Chaitanya Kumar; Sturgeon, Matthew R

    2010-12-01

    Lignin is a biopolymer that comprises up to 35% of woody biomass by dry weight. It is currently underutilized compared to cellulose and hemicellulose, the other two primary components of woody biomass. Lignin has an irregular structure of methoxylated aromatic groups linked by a suite of ether and alkyl bonds which makes it difficult to degrade selectively. However, the aromatic components of lignin also make it promising as a base material for the production of aromatic fuel additives and cyclic chemical feed stocks such as styrene, benzene, and cyclohexanol. Our laboratory research focused on three methods to selectively cleave and deoxygenate purified lignin under mild conditions: acidolysis, hydrogenation and electrocatalysis. (1) Acidolysis was undertaken in CH2Cl2 at room temperature. (2) Hydrogenation was carried out by dissolving lignin and a rhodium catalyst in 1:1 water:methoxyethanol under a 1 atm H2 environment. (3) Electrocatalysis of lignin involved reacting electrically generated hydrogen atoms at a catalytic palladium cathode with lignin dissolved in a solution of aqueous methanol. In all of the experiments, the lignin degradation products were identified and quantified by gas chromatography mass spectroscopy and flame ionization detection. Yields were low, but this may have reflected the difficulty in recovering the various fractions after conversion. The homogeneous hydrogenation of lignin showed fragmentation into monomers, while the electrocatalytic hydrogenation showed production of polyaromatic hydrocarbons and substituted benzenes. In addition to the experiments, promising pathways for the conversion of lignin were assessed. Three conversion methods were compared based on their material and energy inputs and proposed improvements using better catalyst and process technology. A variety of areas were noted as needing further experimental and theoretical effort to increase the feasibility of lignin conversion to fuels.

  3. Spectroscopy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTechtail.Theory ofDidDevelopment Top ScientificTechnologies |DOE RateBusiness

  4. Spectroscopy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque|SensitiveApril 2, 2014 Smith

  5. Simultaneous beta and gamma spectroscopy

    DOE Patents [OSTI]

    Farsoni, Abdollah T. (Corvallis, OR); Hamby, David M. (Corvallis, OR)

    2010-03-23

    A phoswich radiation detector for simultaneous spectroscopy of beta rays and gamma rays includes three scintillators with different decay time characteristics. Two of the three scintillators are used for beta detection and the third scintillator is used for gamma detection. A pulse induced by an interaction of radiation with the detector is digitally analyzed to classify the type of event as beta, gamma, or unknown. A pulse is classified as a beta event if the pulse originated from just the first scintillator alone or from just the first and the second scintillator. A pulse from just the third scintillator is recorded as gamma event. Other pulses are rejected as unknown events.

  6. Charmed baryon spectroscopy with Belle

    SciTech Connect (OSTI)

    Lesiak, Tadeusz [Institute of Nuclear Physics PAN, Radzikowskiego 152, 31-142 Cracow (Poland)

    2007-02-27

    Recent studies concerning charmed baryon spectroscopy, performed by the Belle collaboration, are briefly described. We report the first observation of two new baryons {xi}cx(2980) and {xi}cx(3077), a precise determination of the masses of {xi}c(2645) and {xi}c(2815), observation of the {lambda}c(2940)+ and experimental constraints on the possible spin-parity of the {lambda}c(2880)+. Observations of several exclusive decays of B mesons to the final states containing charmed baryons are also briefly presented.

  7. Development of MEMS photoacoustic spectroscopy

    SciTech Connect (OSTI)

    Robinson, Alex Lockwood; Eichenfield, Matthew S.; Griffin, Benjamin; Harvey, Heidi Alyssa; Nielson, Gregory N.; Okandan, Murat; Langlois, Eric; Resnick, Paul James; Shaw, Michael J.; Young, Ian; Givler, Richard C.; Reinke, Charles M.

    2014-01-01

    After years in the field, many materials suffer degradation, off-gassing, and chemical changes causing build-up of measurable chemical atmospheres. Stand-alone embedded chemical sensors are typically limited in specificity, require electrical lines, and/or calibration drift makes data reliability questionable. Along with size, these "Achilles' heels" have prevented incorporation of gas sensing into sealed, hazardous locations which would highly benefit from in-situ analysis. We report on development of an all-optical, mid-IR, fiber-optic based MEMS Photoacoustic Spectroscopy solution to address these limitations. Concurrent modeling and computational simulation are used to guide hardware design and implementation.

  8. Sandia Energy - Photoionization Mass Spectroscopy

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation of Fe(II)Geothermal Energy &WaterNewPhotoionization Mass Spectroscopy Home

  9. Combining Feedback Absorption Spectroscopy, Amplified Resonance...

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

    On-Board Measurement of Ammonia and Nitrous Oxide Using Feedback Absorption Laser Spectroscopy Combined with Amplified Resonance and Low Pressure Sampling Cummins...

  10. ELECTRON SPECTROSCOPY STUDIES OF CLEAN OXIDE SURFACES, CHEMISORBED MOLECULES AND PHOTO-ASSISTED PROCESSES

    E-Print Network [OSTI]

    Lo, Wei Jen

    2011-01-01

    electron diffraction (LEED), Auger electron spectroscopy (electron diffraction (LEED), Auger electron spectroscopy (The elastic peak: LEED . . . Auger electron spectroscopy

  11. Nonlinear Spectroscopy of Trapped Ions

    E-Print Network [OSTI]

    Frank Schlawin; Manuel Gessner; Shaul Mukamel; Andreas Buchleitner

    2014-10-07

    Nonlinear spectroscopy employs a series of laser pulses to interrogate dynamics in large interacting many-body systems, and has become a highly successful method for experiments in chemical physics. Current quantum optical experiments approach system sizes and levels of complexity which require the development of efficient techniques to assess spectral and dynamical features with scalable experimental overhead. However, established methods from optical spectroscopy of macroscopic ensembles cannot be applied straightforwardly to few-atom systems. Based on the ideas proposed in [M. Gessner et al. New J. Phys. 16 092001 (2014)], we develop a diagrammatic approach to construct nonlinear measurement protocols for controlled quantum systems and discuss experimental implementations with trapped ion technology in detail. These methods in combination with distinct features of ultra-cold matter systems allow us to monitor and analyze excitation dynamics in both the electronic and vibrational degrees of freedom. They are independent of system size, and can therefore reliably probe systems where, e.g., quantum state tomography becomes prohibitively expensive. We propose signals that can probe steady state currents, detect the influence of anharmonicities on phonon transport, and identify signatures of chaotic dynamics near a quantum phase transition in an Ising-type spin chain.

  12. Photoacoustic spectroscopy sample array vessel and photoacoustic spectroscopy method for using the same

    DOE Patents [OSTI]

    Amonette, James E.; Autrey, S. Thomas; Foster-Mills, Nancy S.; Green, David

    2005-03-29

    Methods and apparatus for analysis of multiple samples by photoacoustic spectroscopy are disclosed. Particularly, a photoacoustic spectroscopy sample array vessel including a vessel body having multiple sample cells connected thereto is disclosed. At least one acoustic detector is acoustically coupled with the vessel body. Methods for analyzing the multiple samples in the sample array vessels using photoacoustic spectroscopy are provided.

  13. Photoacoustic spectroscopy sample array vessels and photoacoustic spectroscopy methods for using the same

    DOE Patents [OSTI]

    Amonette, James E.; Autrey, S. Thomas; Foster-Mills, Nancy S.

    2006-02-14

    Methods and apparatus for simultaneous or sequential, rapid analysis of multiple samples by photoacoustic spectroscopy are disclosed. Particularly, a photoacoustic spectroscopy sample array vessel including a vessel body having multiple sample cells connected thereto is disclosed. At least one acoustic detector is acoustically positioned near the sample cells. Methods for analyzing the multiple samples in the sample array vessels using photoacoustic spectroscopy are provided.

  14. Effects of Combustion-Induced Vortex Breakdown on Flashback Limits of Syngas-Fueled Gas Turbine Combustors

    SciTech Connect (OSTI)

    Ahsan Choudhuri

    2011-03-31

    Turbine combustors of advanced power systems have goals to achieve very low pollutants emissions, fuel variability, and fuel flexibility. Future generation gas turbine combustors should tolerate fuel compositions ranging from natural gas to a broad range of syngas without sacrificing operational advantages and low emission characteristics. Additionally, current designs of advanced turbine combustors use various degrees of swirl and lean premixing for stabilizing flames and controlling high temperature NOx formation zones. However, issues of fuel variability and NOx control through premixing also bring a number of concerns, especially combustor flashback and flame blowout. Flashback is a combustion condition at which the flame propagates upstream against the gas stream into the burner tube. Flashback is a critical issue for premixed combustor designs, because it not only causes serious hardware damages but also increases pollutant emissions. In swirl stabilized lean premixed turbine combustors onset of flashback may occur due to (i) boundary layer flame propagation (critical velocity gradient), (ii) turbulent flame propagation in core flow, (iii) combustion instabilities, and (iv) upstream flame propagation induced by combustion induced vortex breakdown (CIVB). Flashback due to first two foregoing mechanisms is a topic of classical interest and has been studied extensively. Generally, analytical theories and experimental determinations of laminar and turbulent burning velocities model these mechanisms with sufficient precision for design usages. However, the swirling flow complicates the flashback processes in premixed combustions and the first two mechanisms inadequately describe the flashback propensity of most practical combustor designs. The presence of hydrogen in syngas significantly increases the potential for flashback. Due to high laminar burning velocity and low lean flammability limit, hydrogen tends to shift the combustor operating conditions towards flashback regime. Even a small amount of hydrogen in a fuel blend triggers the onset of flashback by altering the kinetics and thermophysical characteristics of the mixture. Additionally, the presence of hydrogen in the fuel mixture modifies the response of the flame to the global effects of stretch and preferential diffusion. Despite its immense importance in fuel flexible combustor design, little is known about the magnitude of fuel effects on CIVB induced flashback mechanism. Hence, this project investigates the effects of syngas compositions on flashback resulting from combustion induced vortex breakdown. The project uses controlled experiments and parametric modeling to understand the velocity field and flame interaction leading to CIVB driven flashback.

  15. Laser induced rotation of trapped chiral and achiral nematic droplets

    E-Print Network [OSTI]

    Marjan Mosallaeipour; Yashodhan Hatwalne; N. V. Madhusudana; Sharath Ananthamurthy

    2010-02-05

    We study the response of optically trapped achiral and chiralised nematic liquid crystal droplets to linear as well as circular polarised light. We find that there is internal dissipation in rotating achiral nematic droplets trapped in glycerine. We also demonstrate that some chiralised droplets rotate under linearly polarised light. The best fit to our data on chiralised droplets indicates that rotational frequency of these droplets with radius R is approximately proportional to1/R^2, rather than to 1/R^3.

  16. Quantum Hooke's Law to classify pulse laser induced ultrafast melting

    SciTech Connect (OSTI)

    Hu, Hao; Ding, Hepeng; Liu, Feng

    2015-02-03

    Ultrafast crystal-to-liquid phase transition induced by femtosecond pulse laser excitation is an interesting material's behavior manifesting the complexity of light-matter interaction. There exist two types of such phase transitions: one occurs at a time scale shorter than a picosecond via a nonthermal process mediated by electron-hole plasma formation; the other at a longer time scale via a thermal melting process mediated by electron-phonon interaction. However, it remains unclear what material would undergo which process and why? Here, by exploiting the property of quantum electronic stress (QES) governed by quantum Hooke's law, we classify the transitions by two distinct classes of materials: the faster nonthermal process can only occur in materials like ice having an anomalous phase diagram characterized with dTm/dP < 0, where Tm is the melting temperature and P is pressure, above a high threshold laser fluence; while the slower thermal process may occur in all materials. Especially, the nonthermal transition is shown to be induced by the QES, acting like a negative internal pressure, which drives the crystal into a “super pressing” state to spontaneously transform into a higher-density liquid phase. Our findings significantly advance fundamental understanding of ultrafast crystal-to-liquid phase transitions, enabling quantitative a priori predictions.

  17. Quantum Hooke's Law to classify pulse laser induced ultrafast melting

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

    Hu, Hao; Ding, Hepeng; Liu, Feng

    2015-02-03

    Ultrafast crystal-to-liquid phase transition induced by femtosecond pulse laser excitation is an interesting material's behavior manifesting the complexity of light-matter interaction. There exist two types of such phase transitions: one occurs at a time scale shorter than a picosecond via a nonthermal process mediated by electron-hole plasma formation; the other at a longer time scale via a thermal melting process mediated by electron-phonon interaction. However, it remains unclear what material would undergo which process and why? Here, by exploiting the property of quantum electronic stress (QES) governed by quantum Hooke's law, we classify the transitions by two distinct classes ofmore »materials: the faster nonthermal process can only occur in materials like ice having an anomalous phase diagram characterized with dTm/dP m is the melting temperature and P is pressure, above a high threshold laser fluence; while the slower thermal process may occur in all materials. Especially, the nonthermal transition is shown to be induced by the QES, acting like a negative internal pressure, which drives the crystal into a “super pressing” state to spontaneously transform into a higher-density liquid phase. Our findings significantly advance fundamental understanding of ultrafast crystal-to-liquid phase transitions, enabling quantitative a priori predictions.« less

  18. Laser induced popcornlike conformational transition of nanodiamond as a nanoknife

    SciTech Connect (OSTI)

    Chang, C.-C.; Chen, P.-H.; Chu, H.-L.; Lee, T.-C.; Chou, C.-C.; Chao, J.-I; Su, C.-Y.; Chen, J.S.; Tsai, J.-S.; Tsai, C.-M.; Ho, Y.-P.; Sun, K.W.; Cheng, C.-L.; Chen, F.-R.

    2008-07-21

    Nanodiamond (ND) is surrounded by layers of graphite on its surface. This unique structure feature creates unusual fluorescence spectra, which can be used as an indicator to monitor its surface modification. Meanwhile, the impurity, nitroso (C-N=O) inside the ND can be photolyzed by two-photon absorption, releasing NO to facilitate the formation of a sp{sup 3} diamond structure in the core of ND and transforming it into a sp{sup 2} graphite structure. Such a conformational transition enlarges the size of ND from 8 to 90 nm, resulting in a popcornlike structure. This transition reaction may be useful as nanoknives in biomedical application.

  19. Woodhead Publishing Limited, 2010 Advances in laser-induced plastic

    E-Print Network [OSTI]

    Yao, Y. Lawrence

    in a local increase in temperature, e.g. laser cutting, drilling, welding, in a sense these processes to desired, controllable mechanical deformation, there exist what may be thought of as intermediate steps

  20. Laser induced neutron production by explosion of the deuterium clusters

    SciTech Connect (OSTI)

    Holkundkar, Amol R., E-mail: amol.holkundkar@pilani.bits-pilani.ac.in [Department of Physics, Birla Institute of Technology and Science, Pilani 333 031 (India); Mishra, Gaurav, E-mail: gauravm@barc.gov.in; Gupta, N. K., E-mail: nkgupta@barc.gov.in [Theoretical Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2014-01-15

    The high energy deuterium ions serve as compact source of neutrons when fused with either deuterium or tritium atoms. In view of this, the explosion of the deuterium clusters under the influence of the laser pulse with intensity ranging from 10{sup 15} to 10{sup 19}?W/cm{sup 2} is being studied along with the effect of the cluster radius and inter-cluster distance. The objective of this article is to study the efficiency of the deuterium cluster as a compact source of neutrons under various laser and cluster parameters. It is being observed that the cluster density (number of clusters per unit volume) is quite important to gain high neutron yield.

  1. UV-tunable laser induced phototransformations of matrix isolated anethole

    SciTech Connect (OSTI)

    Krupa, Justyna; Wierzejewska, Maria E-mail: rfausto@ci.uc.pt; Nunes, Cláudio M.; Fausto, Rui E-mail: rfausto@ci.uc.pt

    2014-03-14

    A matrix isolation study of the infrared spectra and structure of anethole (1-methoxy-4-(1-propenyl)benzene) has been carried out, showing the presence of two E conformers (AE1, AE2) of the molecule in the as-deposited matrices. Irradiation using ultraviolet-tunable laser light at 308–307 nm induced conformationally selective phototransformations of these forms into two less stable Z conformers (AZ1, AZ2). The back reactions were also detected upon irradiation at 301 nm. On the whole, the obtained results allow for full assignment of the infrared spectra of all the four experimentally observed anethole isomers and showed that the narrowband UV-induced E-Z photoisomerization is an efficient and selective way to interconvert the two isomers of anethole into each other, with conformational discrimination. Photolysis of anethole was observed as well, with initial methoxyl O–C bond cleavage and formation of CH{sub 3} and p-propenylphenoxy (AR) radicals, followed by radical recombination to form 2-methyl-4-propenyl-2,4-cyclohexadienone, which subsequently undergoes ring-opening generating several conformers of long-chain conjugated ketenes. Interpretation of the experimental observations was supported by density functional theory (B3LYP and B2PLYD) calculations.

  2. Terahertz generation in multiple laser-induced air plasmas

    E-Print Network [OSTI]

    Chen, Meng-Ku; Kim, Jae Hun; Yang, Chia-En; Yin, Stuart Shizhuo; Hui, Rongqing; Ruffin, Paul

    2008-01-01

    of this enhancement effect of the terahertz generation is studied by quantitatively measuring the intensity of the generated terahertz wave as a function of phase difference between adjacent air plasmas. It is found out that the superposition is the main mechanism...

  3. Laser Induced Selective Alignment of Water Spin Isomers

    E-Print Network [OSTI]

    E. Gershnabel; I. Sh. Averbukh

    2008-09-26

    We consider laser alignment of ortho and para spin isomers of water molecules by using strong and short off-resonance laser pulses. A single pulse is found to create a distinct transient alignment and antialignment of the isomeric species. We suggest selective alignment of one isomeric species (leaving the other species randomly aligned) by a pair of two laser pulses.

  4. Laser-induced nonresonant nuclear excitation in muonic atoms

    E-Print Network [OSTI]

    A. Shahbaz; C. Müller; T. J. Buervenich; C. H. Keitel

    2008-12-13

    Coherent nuclear excitation in strongly laser-driven muonic atoms is calculated. The nuclear transition is caused by the time-dependent Coulomb field of the oscillating charge density of the bound muon. A closed-form analytical expression for electric multipole transitions is derived and applied to various isotopes; the excitation probabilities are in general very small. We compare the process with other nuclear excitation mechanisms through coupling with atomic shells and discuss the prospects to observe it in experiment.

  5. COMPETING REACTION CHANNELS IN IR LASER INDUCED UNIMOLECULAR REACTIONS

    E-Print Network [OSTI]

    Berman, M.R.

    2010-01-01

    dihydronaphthalene V-l. ments. styrene (3), o-allyltoluene (arc benzocyclobutene (2), styrene (3), o-allyltoluene (£),amounts of tetralin, styrene and 1,2-dihydronaphthalene. GC

  6. Ultrafast laser-induced changes in optical properties of semiconductors

    SciTech Connect (OSTI)

    Chirila, C. C.; Lim, Freda C. H.; Gavaza, M. G. [Institute of High Performance Computing, 1 Fusionopolis Way, 16-16 Connexis, 138632 (Singapore)

    2012-04-01

    We study the effect of laser radiation on optical properties of semiconductors of industrial interest. The material is pumped with a laser of chosen central frequency, for which the absorption is maximal, thus inducing electron dynamics, which modifies the optical properties. By using an improved theoretical model, we study ultrafast dynamic changes in the refraction index and reflectivity corresponding to a wide frequency-interval of probing radiation and identify that interval where these optical changes are most significant.

  7. Ultra Sensitive Laser Induced Fluorescence Sensor (SEN 4)

    E-Print Network [OSTI]

    Leyla Sabet; Arnaud Benahmed; Chih-Ming Ho

    2006-01-01

    the star topology The received signal at the fusion centerfusion center (FC) – P i is power gain factor, Figure 1: Different generic topologies considered for distributed parameter estimation: linear, star

  8. Laser induced electron acceleration in vacuum K. P. Singha)

    E-Print Network [OSTI]

    Singh, Kunwar Pal

    of the laser wave and initial electron energy. The electric field of the laser wave is taken as E x^A0 cos to much higher energies.4,5 In the beat wave scheme, the laser exerts an axial ponderomotive force of Technology, New Delhi-110016, India Received 12 September 2003; accepted 21 November 2003 Electron

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

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired SolarAboutXuRod Hunt (208) 386-52542 120 Federal Columbia River

  10. Noise autocorrelation spectroscopy with coherent Raman scattering

    E-Print Network [OSTI]

    Loss, Daniel

    LETTERS Noise autocorrelation spectroscopy with coherent Raman scattering XIAOJI G. XU, STANISLAV O to noise. Here, we present a new approach to coherent Raman spectroscopy in which high resolution is achieved by means of deliberately introduced noise. The proposed method combines the efficiency

  11. DIFFUSING ACOUSTIC WAVE TRANSPORT AND SPECTROSCOPY

    E-Print Network [OSTI]

    Page, John

    1 Chapter DIFFUSING ACOUSTIC WAVE TRANSPORT AND SPECTROSCOPY J.H. PAGE, M.L. COWAN Dept. of Physics waves, multiple scattering, energy velocity, Diffusing Acoustic Wave Spectroscopy. Abstract the diffusive transport of ultrasonic waves, and then describe a new ultrasonic technique, Diffusing Acoustic

  12. Gas-Phase Spectroscopy of Biomolecular

    E-Print Network [OSTI]

    de Vries, Mattanjah S.

    Gas-Phase Spectroscopy of Biomolecular Building Blocks Mattanjah S. de Vries1 and Pavel Hobza2 1, REMPI, computational chemistry, spectral hole burning, jet cooling Abstract Gas-phase spectroscopy lends. In recent years, we have seen enormous progress in the study of biomolecular building blocks in the gas

  13. APPLIED SPECTROSCOPY 135A focal point

    E-Print Network [OSTI]

    Denver, University of

    measured as a ratio to the mea- sured emission of CO2 and calibrated by means of a certified cylinder 2190 E. ILIFF AVE. DENVER, COLORADO 80208 Spectroscopy Applied to On-Road Mobile Source Emissions INTRODUCTION N ot to be confused with emis- sion spectroscopy, the detec- tion of mobile source emis- sions

  14. Diffractive optical elements for spectroscopy Hallvard Angelskar

    E-Print Network [OSTI]

    Johansen, Tom Henning

    Diffractive optical elements for spectroscopy by Hallvard Angelsk°ar Submitted in partial;Abstract Diffractive optical elements can be used in spectroscopy instruments to fulfill several tasks to precisely fabricate complex diffractive optical elements with feature sizes below the micrometer scale

  15. RAMAN SPECTROSCOPY OF GRAPHENE AND RELATED MATERIALS

    E-Print Network [OSTI]

    Chen, Yong P.

    structure of graphene. (b) Graphene is a zero-gap semiconductor. Its 2-D nature leads to a linear dispersionChapter 19 RAMAN SPECTROSCOPY OF GRAPHENE AND RELATED MATERIALS Isaac Childres*a,b , Luis A This chapter is a review of the application of Raman spectroscopy in characterizing the properties of graphene

  16. Evolution, biodiversity, taxonomy FTIR spectroscopy and taxonomic purpose

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Evolution, biodiversity, taxonomy FTIR spectroscopy and taxonomic purpose: Contribution. taxonomy / FTIR spectroscopy / Streptococcus / Lactobacillus Résumé -- Apport de la spectroscopie infrarouge à transformée de Fourier en taxonomie : contribution à la classification de bactéries lactiques

  17. The Spectroscopy of Neutron-Rich sdf-Shell Nuclei Using the CLARA-PRISMA Setup

    SciTech Connect (OSTI)

    Liang, X.; Hodsdon, A.; Chapman, R.; Burns, M.; Keyes, K.; Ollier, J.; Papenberg, A.; Spohr, K.; Azaiez, F.; Ibrahim, F.; Stanoiu, M.; Haas, F.; Caurier, E.; Curien, D.; Nowacki, F.; Salsac, M.-D.; Bazzacco, D.; Beghini, S.; Farnea, E.; Menegazzo, R.

    2006-08-14

    Since the discovery of the breakdown of shell effects in very neutron-rich N=20 and 28 nuclei, studies of the properties of nuclei far from stability have been of intense interest since they provide a unique opportunity to increase our understanding of nuclear interactions in extreme conditions and often challenge our theoretical models.Deep-inelastic processes can be used to populated high spin states of neutron-rich nuclei. In the deep-inelastic processes, an equilibration in N/Z between the target and projectile nuclei is achieved. For most heavy neutron-rich target nuclei, the N/Z ratio is 1.5 - 1.6, while for the possible neutron-rich sdf-shell projectile it is about 1.2. Thus by using deep-inelastic processes one can populate neutron-rich nuclei around N=20 and N=28.New results for the spectroscopy of neutron-rich N=22 36Si and 37P are presented here.

  18. Updated Spitzer emission spectroscopy of bright transiting hot...

    Office of Scientific and Technical Information (OSTI)

    Updated Spitzer emission spectroscopy of bright transiting hot Jupiter HD 189733b Citation Details In-Document Search Title: Updated Spitzer emission spectroscopy of bright...

  19. Raman spectroscopy in hot compressed hydrogen and nitrogen -...

    Office of Scientific and Technical Information (OSTI)

    Raman spectroscopy in hot compressed hydrogen and nitrogen - implications for the intramolecular potential Citation Details In-Document Search Title: Raman spectroscopy in hot...

  20. THRESHOLD RADIOACTIVITY FOR BULK FOOD SAMPLES BY GAMMA SPECTROSCOPY...

    Office of Scientific and Technical Information (OSTI)

    THRESHOLD RADIOACTIVITY FOR BULK FOOD SAMPLES BY GAMMA SPECTROSCOPY Citation Details In-Document Search Title: THRESHOLD RADIOACTIVITY FOR BULK FOOD SAMPLES BY GAMMA SPECTROSCOPY...

  1. Noninvasive glucose sensing by transcutaneous Raman spectroscopy

    E-Print Network [OSTI]

    Shih, Wei-Chuan

    We present the development of a transcutaneous Raman spectroscopy system and analysis algorithm for noninvasive glucose sensing. The instrument and algorithm were tested in a preclinical study in which a dog model was used. ...

  2. Scanning tunneling spectroscopy of unoccupied surface resonances

    E-Print Network [OSTI]

    Persson, Mats

    - induced series, produced when an electron is trapped in a potential well define* *d by the image Scanning tunneling spectroscopy of unoccupied surface resonances at free-electron-like metal surfaces. T. Fond'eny, S

  3. Developments and advances in nonlinear terahertz spectroscopy

    E-Print Network [OSTI]

    Brandt, Nathaniel Curran

    2014-01-01

    Nonlinear terahertz (THz) spectroscopy is a rapidly developing field, which is concerned with driving and observing nonlinear material responses in the THz range of the electromagnetic spectrum. In this thesis, I present ...

  4. Gas-Phase IR Spectroscopy of Nucleobases

    E-Print Network [OSTI]

    de Vries, MS

    2015-01-01

    ionization spectroscopy of gas phase guanine: Evidence for2007) Imino tautomers of gas-phase guanine from mid-infraredAlkali Metal Cation Size on Gas Phase Conformation. J. Am.

  5. Anion Photoelectron Spectroscopy of Exotic Species

    E-Print Network [OSTI]

    Yen, Terry A.

    2010-01-01

    Hatami, F. , et al. , InP quantum dots embedded in GaP:spectroscopy of InP quantum dots. Journal of Physicalfor InP with applications to large quantum dots. Physical

  6. A Narrowband Ultrasonic Spectroscopy Technique for the Inspection of

    E-Print Network [OSTI]

    This thesis introduces a narrowband ultrasonic spectroscopy (NBUS) technique for non-destructive testing. NBUS

  7. The singlettriplet spectroscopy of 1,3-butadiene using cavity ring-down spectroscopy

    E-Print Network [OSTI]

    Zwier, Timothy S.

    The singlet­triplet spectroscopy of 1,3-butadiene using cavity ring-down spectroscopy Allison G of gas-phase 1,3-butadiene (C4H6) has been investigated over the region from 20 500 to 23 000 cm 1 using polyene, the electronic struc- ture of the ground and excited electronic states of 1,3- butadiene has

  8. Development of Real-Time Coal Monitoring Instrument

    SciTech Connect (OSTI)

    Rajan Gurjar, Ph.D.

    2010-06-17

    Relying on coal for energy requires optimizing the extraction of heat content from various blends of coal fuel and reducing harmful constituents and byproducts. Having a real-time measurement instrument provides relevant information about toxic constituents released in the atmosphere from burning coal and optimizes the performance of a power plant. A few commercial instruments exist and have been in operation for more than a decade. However, most of these instruments are based on radioactive sources and are bulky, expensive and time-consuming. The proposed instrument is based on the Laser Induced Breakdown Spectroscopy (LIBS). The advantage of LIBS is that it is a standoff instrument, does not require sample preparation and provides precise information about sample constituents.

  9. Feedstock Quality Factor Calibration and Data Model Development

    SciTech Connect (OSTI)

    Richard D. Boardman; Tyler L. Westover; Garold L. Gresham

    2010-05-01

    The goal of the feedstock assembly operation is to deliver uniform, quality-assured feedstock materials that will enhance downstream system performance by avoiding problems in the conversion equipment. In order to achieve this goal, there is a need for rapid screening tools and methodologies for assessing the thermochemical quality characteristics of biomass feedstock through the assembly process. Laser-induced breakdown spectroscopy (LIBS) has been identified as potential technique that could allow rapid elemental analyses of the inorganic content of biomass feedstocks; and consequently, would complement the carbohydrate data provided by near-infrared spectrometry (NIRS). These constituents, including Si, K, Ca, Na, S, P, Cl, Mg, Fe and Al, create a number of downstream problems in thermochemical processes. In particular, they reduce the energy content of the feedstock, influence reaction pathways, contribute to fouling and corrosion within systems, poison catalysts, and impact waste streams.

  10. Raman subrecoil spectroscopy of cold cesium atoms

    E-Print Network [OSTI]

    J. Ringot; P. Szriftgiser; J. C. Garreau

    2001-07-28

    We describe and characterize a setup for subrecoil stimulated Raman spectroscopy of cold cesium atoms. We study in particular the performances of a method designed to active control and stabilization of the magnetic fields across a cold-atom cloud inside a small vacuum cell. The performance of the setup is monitored by {\\em copropagative-beam} stimulated Raman spectroscopy of a cold cesium sample. The root mean-square value of the residual magnetic field is 300 $\\mu G$, with a compensation bandwidth of 500 Hz. The shape of the observed spectra is theoretically interpreted and compares very well to numerically generated spectra.

  11. A Brief History of Spectroscopy on EBIT

    SciTech Connect (OSTI)

    Beiersdorfer, P

    2007-02-28

    In the autumn of 1986, the first electron beam ion trap, EBIT, was put into service as a light source for the spectroscopy of highly charged ions. On the occasion of the twentieth anniversary of EBIT, we review its early uses for spectroscopy, from the first measurements of x rays from L-shell xenon ions in 1986 to its conversion to SuperEBIT in 1992 and rebirth as EBIT-I in 2001. Together with their sibling, EBIT-II, these machines have been used at Livermore to perform a multitude of seminal studies of the physics of highly charged ions.

  12. Spectroscopy of Supercapacitor Electrodes In Operando

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque|SensitiveApril 2, 2014 SmithSpectroscopy ofSpectroscopy of

  13. Noise spectroscopy of an optical microresonator

    SciTech Connect (OSTI)

    Kozlov, G. G.

    2013-05-15

    The noise spectrum is calculated for the intensity of light transmitted through an optical microresonator whose thickness experiences thermal oscillations. The noise spectrum reveals a maximum at the frequency of an acoustic mode localized in the optical microresonator and depends on the size of the illuminated region. The noise intensity estimates show that it can be detected by the modern noise spectroscopy technique.

  14. Inelastic Tunneling Spectroscopy in Unconventional Superconductors

    E-Print Network [OSTI]

    Inelastic Tunneling Spectroscopy in Unconventional Superconductors Molecular Vibration and Single Superconductors ­ p.1/13 #12;Old Results R.C. Jaklevic and J. Lambe, Phys. Rev. Lett. 17, 1139-1140 (1966 in Unconventional Superconductors ­ p.2/13 #12;STM observation of local inelastic mode B.C. Stipe, M.A Rezaei, and W

  15. Nanoparticles and nanowires: synchrotron spectroscopy studies

    SciTech Connect (OSTI)

    Sham, T.K.

    2008-08-11

    This paper reviews the research in nanomaterials conducted in our laboratory in the last decade using conventional and synchrotron radiation techniques. While preparative and conventional characterisation techniques are described, emphasis is placed on the analysis of nanomaterials using synchrotron radiation. Materials of primary interests are metal nanoparticles and semiconductor nanowires and nanoribbons. Synchrotron techniques based on absorption spectroscopy such as X-ray absorption fine structures (XAFS), which includes X-ray absorption near edge structures (XANES) and extended X-ray absorption fine structures (EXFAS), and de-excitation spectroscopy, including X-ray excited optical luminescence (XEOL), time-resolved X-ray excited optical luminescence (TRXEOL) and X-ray emission spectroscopy (XES) are described. We show that the tunability, brightness, polarisation and time structure of synchrotron radiation are providing unprecedented capabilities for nanomaterials analysis. Synchrotron studies of prototype systems such as gold nanoparticles, 1-D nanowires of group IV materials, C, Si and Ge as well as nanodiamond, and compound semiconductors, ZnS, CdS, ZnO and related materials are used to illustrate the power and unique capabilities of synchrotron spectroscopy in the characterisation of local structure, electronic structure and optical properties of nanomaterials.

  16. Laser spectroscopy and dynamics of transient species

    SciTech Connect (OSTI)

    Clouthier, D.J.

    1993-12-01

    The goal of this program is to study the vibrational and electronic spectra and excited state dynamics of a number of transient sulfur and oxygen species. A variety of supersonic jet techniques, as well as high resolution FT-IR and intracavity dye laser spectroscopy, have been applied to these studies.

  17. Spectroscopy and decays of charm and bottom

    SciTech Connect (OSTI)

    Butler, J.N.

    1997-10-01

    After a brief review of the quark model, we discuss our present knowledge of the spectroscopy of charm and bottom mesons and baryons. We go on to review the lifetimes, semileptonic, and purely leptonic decays of these particles. We conclude with a brief discussion B and D mixing and rare decays.

  18. Submitted to Applied Spectroscopy December 2006

    E-Print Network [OSTI]

    of the components. However, the blends exhibited greatly reduced PMMA backbone vibrational intensities, suggesting biomedical applications such as bone fillers or bone grafts. Of the two blend components, one is transientSubmitted to Applied Spectroscopy December 2006 Raman Characterization in Blends of Poly

  19. Optical spectroscopy of bilayer Baisong Geng

    E-Print Network [OSTI]

    Zettl, Alex

    -gate bilayer graphene device, we were able to control the carrier doping and a semiconductor bandgap the inversion symmetry between the top and bottom graphene layers. This semiconductor bandgap canOptical spectroscopy of bilayer graphene Baisong Geng 1,2 , Jason Horng 1 , Yuanbo Zhang 1

  20. A New Spin on Photoemission Spectroscopy

    SciTech Connect (OSTI)

    Advanced Light Source; Jozwiak, Chris

    2008-12-18

    The electronic spin degree of freedom is of general fundamental importance to all matter. Understanding its complex roles and behavior in the solid state, particularly in highly correlated and magnetic materials, has grown increasingly desirable as technology demands advanced devices and materials based on ever stricter comprehension and control of the electron spin. However, direct and efficient spin dependent probes of electronic structure are currently lacking. Angle Resolved Photoemission Spectroscopy (ARPES) has become one of the most successful experimental tools for elucidating solid state electronic structures, bolstered bycontinual breakthroughs in efficient instrumentation. In contrast, spin-resolved photoemission spectroscopy has lagged behind due to a lack of similar instrumental advances. The power of photoemission spectroscopy and the pertinence of electronic spin in the current research climate combine to make breakthroughs in Spin and Angle Resolved Photoemission Spectroscopy (SARPES) a high priority . This thesis details the development of a unique instrument for efficient SARPES and represents a radical departure from conventional methods. A custom designed spin polarimeter based on low energy exchange scattering is developed, with projected efficiency gains of two orders of magnitude over current state-of-the-art polarimeters. For energy analysis, the popular hemispherical analyzer is eschewed for a custom Time-of-Flight (TOF) analyzer offering an additional order of magnitude gain in efficiency. The combined instrument signifies the breakthrough needed to perform the high resolution SARPES experiments necessary for untangling the complex spin-dependent electronic structures central to today?s condensed matter physics.

  1. Oil Classification with Fluorescence Spectroscopy Engineering Physics

    E-Print Network [OSTI]

    Oldenburg, Carl von Ossietzky Universität

    detected by these channels. The investigation used three methods to examine crude oil, heavy oil, sludge1 Oil Classification with Fluorescence Spectroscopy Engineering Physics Master of Engineering and classification of oil spills on water surfaces. It is an overview of the laser remote sensor technique

  2. Extensions of quartz-enhanced photoacoustic spectroscopy

    E-Print Network [OSTI]

    Masurkar, Amrita V

    2009-01-01

    The goal of this thesis was to perform quartz-enhanced photoacoustic spectroscopy (QEPAS) on trace concentrations of NH3 in the 1.53 pm region with a DFB laser without the use of a resonating cavity. I analyzed the process ...

  3. Defect analysis using resonant ultrasound spectroscopy 

    E-Print Network [OSTI]

    Flynn, Kevin Joseph

    2009-05-15

    ....................................................................... 6 1.3 Resonant NDT Methods....................................................................... 7 1.3.1 Impact Excitation Technique ...................................................... 7 1.3.2 Resonant Ultrasound Spectroscopy... Page Figure 3.5 First torsional mode about X axis (X Torsion 1) for samples without (left) and with (right) the notch...................................... 44 Figure 3.6 First bending mode about Y axis (Y Bend 1) for samples without (left...

  4. Theoretical and experimental investigation of polarization spectroscopy 

    E-Print Network [OSTI]

    Hanna, Sherif Fayez

    2001-01-01

    , Sweden. Polarization spectroscopy saturation curves in the co-propagating beam geometry from the excitation of OH A ²[]?-X²[] (0,0) at the Q?(8) line for sub-atmospheric pressures have been fitted to the proposed model. The model proposed in this work...

  5. Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy

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

    Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Wednesday, 29 October 2008 00:00 Graphene-a single layer...

  6. Raman spectroscopy of complex defined media: biopharmaceutical applications

    E-Print Network [OSTI]

    Ram, Rajeev J.

    , grown in shake flasks in batch fermentation mode, using Raman spectroscopy and explicit model glutamine, glutamate, glucose, la

  7. Imaging Fourier transform spectroscopy with multi-aperture telescopes

    E-Print Network [OSTI]

    Fienup, James R.

    Imaging Fourier transform spectroscopy with multi-aperture telescopes Samuel T. Thurman and James R Hanover St., Palo Alto, CA 94304 Abstract: Fourier spectroscopy can be performed with multi Society of America OCIS codes: (300.6300) Spectroscopy, Fourier transforms; (110.6770) Telescopes; (120

  8. Fourier Transform Heterodyne Spectroscopy of Liquid Interfaces A thesis presented

    E-Print Network [OSTI]

    Mazur, Eric

    Fourier Transform Heterodyne Spectroscopy of Liquid Interfaces A thesis presented by Doo Soo Chung Abstract This thesis describes the application of a novel Fourier transform heterodyne spectroscopy of fluid interfaces 3 1.4 Organization of this thesis 5 2 Fourier Transform Heterodyne Spectroscopy 7 2

  9. Introduction and Motivation Experimental Methods in Meson Spectroscopy

    E-Print Network [OSTI]

    Credé, Volker

    Introduction and Motivation Experimental Methods in Meson Spectroscopy Glueballs and Light Mesons, Italy 03/15/2010 V. Credé Glueballs and Light-Meson Spectroscopy #12;Introduction and Motivation Summary and Outlook Outline 1 Introduction and Motivation The Quark Model of Hadrons Meson Spectroscopy 2

  10. Transition state spectroscopy of the I + HI reaction in clusters: Photoelectron spectroscopy of (n = 115)IHI-- Ar

    E-Print Network [OSTI]

    Neumark, Daniel M.

    Transition state spectroscopy of the I + HI reaction in clusters: Photoelectron spectroscopy of (n spectroscopy and dynamics of the I ] HI reaction by measuring the anion photoelectron (PE) spectra Ar, and BrHI~ É Ar were studied in our laboratory. In this paper weIHI~ É N 2 O,18,19 examine

  11. Imaging of the spatial distribution of atoms in an optical-breakdown plasma with one-dimensional coherent hyper-Raman scattering

    SciTech Connect (OSTI)

    Akimov, Denis A; Zheltikov, Aleksei M; Koroteev, Nikolai I; Naumov, A N; Fedotov, Andrei B; Miles, R B; Sidorov-Biryukov, D A

    1998-12-31

    A technique based on coherent four-wave mixing with a hyper-Raman resonance in wide beams was developed for line-by-line reconstruction of the spatial distribution of excited atoms in a laser-produced plasma. This method was used to study the spatial distribution of excited lead atoms in an optical-breakdown plasma formed on a metal target. A comparison was made of the technique of constructing plasma images line-by-line with a four-photon technique of point-by-point measurements. Estimates were obtained of the spatial resolution of the proposed technique. Potential applications of this approach in plasma diagnostics were analysed. (interaction of laser radiation with matter. laser plasma)

  12. Anode initiated impulse breakdown in water: the dependence on pulse rise time for nanosecond and sub-nanosecond pulses and initiation mechanism based on electrostriction

    E-Print Network [OSTI]

    Seepersad, Yohan; Dobrynin, Danil

    2015-01-01

    The effect of the voltage rise time on nanosecond and sub-nanosecond impulse breakdown of distilled water is studied. The dependence of anode initiated streamer inception on this parameter is shown to be more intricate than previously reported, particularly as it relates to mechanisms directly in the liquid phase. Dynamics of the emission phase for sub-nanosecond pulses with 600ps rise time are presented to enable comparison with previous work on nanosecond initiation features. Schlieren imaging is also used to show the development of optical density perturbations and rarefactions as a result of electrostriction in the liquid which were previously found for nanosecond pulses as well. The mechanism of nanopore generation in the liquid due to fast impulses proposed by Shneider, Pekker and Fridman is used to explain the results.

  13. Chiral specific electron vortex beam spectroscopy

    E-Print Network [OSTI]

    J. Yuan; S. M. Lloyd; M. Babiker

    2013-07-29

    Electron vortex beams carry well-defined orbital angular momentum (OAM) about the propagation axis. Such beams are thus characterised by chirality features which make them potentially useful as probes of magnetic and other chiral materials. An analysis of the inelastic processes in which electron vortex beams interact with atoms and which involve OAM exchange is outlined, leading to the multipolar selection rules governing this chiral specific electron vortex beam spectroscopy. Our results show clearly that the selection rules are dependent on the dynamical state and location of the atoms involved. In the most favorable scenario, this form of electron spectroscopy can induce magnetic sublevel transitions which are commonly probed using circularly polarized photon beams.

  14. Trace Explosive Detection using Photothermal Deflection Spectroscopy

    SciTech Connect (OSTI)

    Krause, Adam R; Van Neste, Charles W; Senesac, Larry R; Thundat, Thomas George; Finot, Eric

    2008-01-01

    Satisfying the conditions of high sensitivity and high selectivity using portable sensors that are also reversible is a challenge. Miniature sensors such as microcantilevers offer high sensitivity but suffer from poor selectivity due to the lack of sufficiently selective receptors. Although many of the mass deployable spectroscopic techniques provide high selectivity, they do not have high sensitivity. Here, we show that this challenge can be overcome by combining photothermal spectroscopy on a bimaterial microcantilever with the mass induced change in the cantilever's resonance frequency. Detection using adsorption-induced resonant frequency shift together with photothermal deflection spectroscopy shows extremely high selectivity with a subnanogram limit of detection for vapor phase adsorbed explosives, such as pentaerythritol tetranitrate (PETN), cyclotrimethylene trinitramine (RDX), and trinitrotoluene (TNT).

  15. (Resonance ionization spectroscopy and its applications)

    SciTech Connect (OSTI)

    Ramsey, J.M.

    1990-10-11

    The Fifth International Symposium in Resonance Ionization Spectroscopy and Its Applications was attended. The Joint Research Centre of the European Communities at Ispra, Italy was also visited. The traveler presented an invited talk, chaired a meeting session and gave an impromptu presentation on how current laser technology limits the development of commercial instrumentation based upon Resonance Ionization Spectroscopy. The conference was truely international with scientists from 19 countries and less than 1/4 from the US. The meeting also provided a health mixture of experimentalists and theoreticians. Technical developments reported included the use of electric field ionization from laser prepared Rydberg states as a way to reduce background signals and commercial development of an optical parametric oscillator for replacing pulsed dye laser. A speaker from the Soviet Union suggested their willingness to market hardware they have developed based upon the resonance ionization technique.

  16. Infrared microcalorimetric spectroscopy using quantum cascade lasers

    SciTech Connect (OSTI)

    Morales Rodriguez, Marissa E [ORNL; Senesac, Larry R [ORNL; Rajic, Slobodan [ORNL; Lavrik, Nickolay V [ORNL; Smith, Barton [ORNL; Datskos, Panos G [ORNL

    2013-01-01

    We have investigated an infrared (IR) microcalorimetric spectroscopy technique that can be used to detect the presence of trace amounts of target molecules. The chemical detection is accomplished by obtaining the IR photothermal spectra of molecules absorbed on the surface of uncooled thermal micromechanical detectors. IR microcalorimetric spectroscopy requires no chemical specific coatings and the chemical specificity of the presented method is a consequence of the wavelength-specific absorption of IR photons from tunable quantum cascade lasers due to vibrational spectral bands of the analyte. We have obtained IR photothermal spectra for trace concentrations of RDX and a monolayer of 2-mercaptoethanol, over the wavelength region from 6 to 10 m. We found that in this wavelength region both chemicals exhibit a number of photothermal absorption features that are in good agreement with their respective IR spectra.

  17. Meson Spectroscopy At Jlab At 12 Gev

    SciTech Connect (OSTI)

    Fegan, Stuart

    2014-12-01

    The 12 GeV upgrade to the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab will enable a new generation of experiments in hadronic nuclear physics, seeking to address fundamental questions in our understanding of QCD. The existence of exotic states, suggested by both quark models and lattice calculations, would allow gluonic degrees of freedom to be explored, and may help explain the role played by gluons in the QCD interaction. This article will review the meson spectroscopy program being planned at the lab following the 12 GeV upgrade, utilising real and quasi-real photon beams in two of the lab's four experimental halls, whose distinct capabilities will enable an extensive set of spectroscopy experiments to be performed at the same facility.

  18. Spin noise spectroscopy of ZnO

    SciTech Connect (OSTI)

    Horn, H.; Berski, F.; Hübner, J.; Oestreich, M.; Balocchi, A.; Marie, X.; Mansur-Al-Suleiman, M.; Bakin, A.; Waag, A.

    2013-12-04

    We investigate the thermal equilibrium dynamics of electron spins bound to donors in nanoporous ZnO by optical spin noise spectroscopy. The spin noise spectra reveal two noise contributions: A weak spin noise signal from undisturbed localized donor electrons with a dephasing time of 24 ns due to hyperfine interaction and a strong spin noise signal with a spin dephasing time of 5 ns which we attribute to localized donor electrons which interact with lattice defects.

  19. Dielectric breakdown properties of hot SF{sub 6}-CO{sub 2} mixtures at temperatures of 300–3500?K and pressures of 0.01–1.0?MPa

    SciTech Connect (OSTI)

    Zhong, Linlin; Yang, Aijun; Wang, Xiaohua, E-mail: xhw@mail.xjtu.edu.cn; Liu, Dingxin; Wu, Yi; Rong, Mingzhe, E-mail: mzrong@mail.xjtu.edu.cn [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049 (China)] [State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049 (China)

    2014-05-15

    Recently, much attention has been paid to SF{sub 6}-CO{sub 2} mixtures as one of substitutes for pure SF{sub 6} gas. In this paper, the dielectric breakdown properties of hot SF{sub 6}-CO{sub 2} mixtures are investigated at temperatures of 300–3500?K and pressures of 0.01–1.0?MPa. Under the assumptions of local thermodynamic equilibrium and local chemical equilibrium, the equilibrium compositions of hot SF{sub 6}-CO{sub 2} mixtures with different CO{sub 2} proportions are obtained based on Gibbs free energy minimization. The cross sections for interactions between electrons and neutral species are presented. Some unknown ionization cross sections are determined theoretically using Deutsch–Märk (DM) formalism based on quantum chemistry. Two-term Boltzmann equation is adopted to calculate the electron energy distribution function, reduced ionization coefficient, reduced attachment coefficient, and reduced effective ionization coefficient. Then the reduced critical electric field strength of mixtures, corresponding to dielectric breakdown performances, is determined when the generation and loss of electrons are balanced. Finally, the influences of temperature, pressure, and CO{sub 2} proportion on the reduced critical electric field strength are studied. It is found that a large percentage of CO{sub 2} can obviously reduce concentrations of high-energy electrons. At temperatures above 1750?K, an addition of CO{sub 2} to SF{sub 6} gas can enhance dielectric breakdown performances. However, at low temperatures, too much CO{sub 2} added into mixtures can reduce dielectric breakdown abilities. In addition, increasing gas pressure can improve dielectric breakdown performances. But the influence will be no more significant if pressure is over 0.8?MPa.

  20. Analog detection for cavity lifetime spectroscopy

    DOE Patents [OSTI]

    Zare, Richard N. (Stanford, CA); Harb, Charles C. (Palo Alto, CA); Paldus, Barbara A. (Mountain View, CA); Spence, Thomas G. (Palo Alto, CA)

    2003-01-01

    An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

  1. Analog detection for cavity lifetime spectroscopy

    DOE Patents [OSTI]

    Zare, Richard N. (Stanford, CA); Harb, Charles C. (Palo Alto, CA); Paldus, Barbara A. (Mountain View, CA); Spence, Thomas G. (Palo Alto, CA)

    2001-05-15

    An analog detection system for determining a ring-down rate or decay rate 1/.tau. of an exponentially decaying ring-down beam issuing from a lifetime or ring-down cavity during a ring-down phase. Alternatively, the analog detection system determines a build-up rate of an exponentially growing beam issuing from the cavity during a ring-up phase. The analog system can be employed in continuous wave cavity ring-down spectroscopy (CW CRDS) and pulsed CRDS (P CRDS) arrangements utilizing any type of ring-down cavity including ring-cavities and linear cavities.

  2. Note: Low energy inverse photoemission spectroscopy apparatus

    SciTech Connect (OSTI)

    Yoshida, Hiroyuki, E-mail: yoshida@e.kuicr.kyoto-u.ac.jp [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan)] [Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011 (Japan)

    2014-01-15

    An apparatus for the low-energy inverse photoemission spectroscopy is described. In this technique, low energy electron having kinetic energy below 4 eV is incident to the sample and detect the emitted photons in the near ultraviolet range (below 5 eV, longer than 250 nm) to investigate the unoccupied states of the solid materials. Compared with the prototype apparatus reported previously [H. Yoshida, Chem. Phys. Lett. 539–540, 180–185 (2012)], the collection efficiency of photons is improved by a factor of four and practically any conductive substrates can be used. The overall resolution is 0.27 eV.

  3. B and D spectroscopy at LEP

    SciTech Connect (OSTI)

    Muheim, Franz

    1999-02-17

    Results from the four LEP experiments ALEPH, DELPHI, L3, and OPAL on the spectroscopy of B and charmed mesons are presented. The predictions of Heavy Quark Effective Theory (HQET) for the masses and the widths of excited L=1 B mesons are supported by a new measurement from L3. A few B{sub c}{sup +} candidate events have masses consistent with the recent CDF observation and the predictions. New results on D** production and B{yields}D**l{nu} are also presented. The evidence for a D*{sup '} meson reported recently by DELPHI is not supported by OPAL and CLEO.

  4. Ultrafast Spectroscopy of Warm Dense Matter

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservationBio-Inspired SolarAbout /Two0 - 19 Publications 1.Design » Design forSpectroscopy

  5. Spectroscopy of Supercapacitor Electrodes In Operando

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect Photovoltaics -7541C.3 Special Report:Spectroscopic ion beamSpectroscopy of

  6. Spectroscopy of Supercapacitor Electrodes In Operando

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect Photovoltaics -7541C.3 Special Report:Spectroscopic ion beamSpectroscopy

  7. Spectroscopy of Supercapacitor Electrodes In Operando

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect Photovoltaics -7541C.3 Special Report:Spectroscopic ionSpectroscopy of

  8. Ultrafast Spectroscopy of Warm Dense Matter

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPPfinal design andBiofuelsUltrafastUltrafast Spectroscopy of

  9. Ultrafast Spectroscopy of Warm Dense Matter

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPPfinal design andBiofuelsUltrafastUltrafast Spectroscopy

  10. Spectroscopy of Supercapacitor Electrodes In Operando

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque|SensitiveApril 2, 2014 SmithSpectroscopy of Supercapacitor

  11. Spectroscopy of Supercapacitor Electrodes In Operando

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity ofkandz-cm11 Outreach Home RoomPreservation ofAlbuquerque|SensitiveApril 2, 2014 SmithSpectroscopy of

  12. Laser Focus World highlights Kaminski's home-grown ARPES spectroscopy...

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

    Laser Focus World highlights Kaminski's home-grown ARPES spectroscopy system Laser Focus World senior editor Gail Overton wrote a story on angled-resolved photo-emission...

  13. Two-photon spectroscopy of excitons with entangled photons

    E-Print Network [OSTI]

    Schlawin, F; Schlawin, F; Mukamel, S

    2013-01-01

    probe experiment with entangled photons. The two beams arethe light state changes from twin photons to squeezed light.139, 244110 (2013) Two-photon spectroscopy of excitons with

  14. Optical Spectroscopy for Materials Applications | The Ames Laboratory

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

    Optical Spectroscopy for Materials Applications The two main objectives of the Smith research group are: (1) to measure the organization and dynamics of biological structures, and...

  15. 10 Questions for a Spectroscopy Expert: Nancy Hess | Department...

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

    share how she's using molecular level spectroscopy to protect water supplies and advance carbon capture and sequestration technologies, and how the Apollo missions, Jacques...

  16. Diffusing acoustic wave spectroscopy M. L. Cowan,1

    E-Print Network [OSTI]

    Page, John

    Diffusing acoustic wave spectroscopy M. L. Cowan,1 I. P. Jones,1, * J. H. Page,1,2, and D. A. Weitz called diffusing acoustic wave spec- troscopy DAWS . In this technique, the motion of the scatterers e the particle velocity correlation function. Potential appli- cations of diffusing acoustic wave spectroscopy

  17. Laser Locking with Doppler-free Saturated Absorption Spectroscopy

    E-Print Network [OSTI]

    Novikova, Irina

    - 1 - Laser Locking with Doppler-free Saturated Absorption Spectroscopy Paul L. Stubbs, Advisor the frequency of a 795 nm diode laser using a saturated absorption spectroscopy method. Laser locking in AMO physics is done to stabilize the frequency of lasers used in the laboratory in order to make results more

  18. Optical Spectroscopy of Hydrogenic Atoms MIT Department of Physics

    E-Print Network [OSTI]

    Seager, Sara

    Optical Spectroscopy of Hydrogenic Atoms MIT Department of Physics (Dated: September 1, 2013) This experiment is an exercise in optical spectroscopy in a study of the spectra of "hydrogenic" atoms, i.e. atoms with one "optical" electron outside a closed shell of other electrons. Measurements include finding

  19. THZ TRANSMISSION SPECTROSCOPY APPLIED TO DIELECTRICS AND MICROWAVE CERAMICS

    E-Print Network [OSTI]

    KuÂ?el, Petr

    THZ TRANSMISSION SPECTROSCOPY APPLIED TO DIELECTRICS AND MICROWAVE CERAMICS ALEXEJ PASHKIN, ELENA of Ba(Mg1/3Ta2/3)O3 (BMT) high-permittivity microwave ceramics was measured in the sub; time-resolved spectroscopy; microwave ceramics INTRODUCTION The method of time-domain terahertz

  20. EUV spectroscopy on the SSPX spheromak

    SciTech Connect (OSTI)

    Clementson, J T; Beiersdorfer, P; Gu, M F; McLean, H S; Wood, R D

    2008-03-17

    EUV plasma spectroscopy is one the diagnostics implemented at the Sustained Spheromak Physics Experiment (SSPX) at the Lawrence Livermore National Laboratory. A grating spectrometer covering the spectral region of 25-450 {angstrom} with a resolution of 0.4 {angstrom} was used as an impurity diagnostic to monitor the plasmas and to carry out atomic physics research. Several low-Z impurities have been found in the spheromak, notably B, C, N, and O. Of the heavier elements, Ti, Cu, and W were found in the plasmas. As a relatively dense and low-temperature laboratory plasma device, SSPX served as an excellent radiation source for investigation of atomic spectra in a regime not readily attained in other devices. We have injected atomic titanium and tungsten hexacarbonyl into the spheromak under different operating conditions. We also report on electron temperature and electron density measurements based on the K{alpha} lines from B IV at 60 {angstrom}.

  1. TOF spectroscopy measurement using waveform digitizer

    E-Print Network [OSTI]

    Longxiang Liu; Hongwei Wang; Yugang Ma; Xiguang Cao; Xiangzhou Cai; Jingen Chen; Guilin Zhang; Jianlong Han; Guogiang Zhang; Jifeng Hu; Xiaohe Wang

    2015-09-17

    The photoneutron source (PNS, phase 1), an electron linear accelerator (linac)-based pulsed neutron facility that uses the time-of-flight (TOF) technique, was constructed for the acquisition of nuclear data from the thorium molten salt reactor(TMSR) at the Shanghai Institute of Applied Physics (SINAP). The neutron detector signal, with the information on the pulse arrival time, pulse shape, and pulse height, was recorded by using a waveform digitizer (WFD). By using the pulse height and pulse-shape discrimination (PSD) analysis to identify neutrons and $\\gamma$-rays, the neutron TOF spectrum was obtained by employing a simple electronic design, and a new WFD-based DAQ system was developed and tested in this commissioning experiment. The developed DAQ system is characterized by a very high efficiency with respect to millisecond neutron TOF spectroscopy

  2. Review of Flicker Noise Spectroscopy in Electrochemistry

    E-Print Network [OSTI]

    Timashev, Serge F; 10.1142/S0219477507003829

    2008-01-01

    This review presents the fundamentals of Flicker-Noise Spectroscopy (FNS), a general phenomenological methodology in which the dynamics and structure of complex systems, characterized by nonlinear interactions, dissipation, and inertia, are analyzed by extracting information from various signals with stochastically varying components generated by the systems. The basic idea of FNS is to treat the correlation links present in sequences of different irregularities, such as spikes, "jumps", and discontinuities in derivatives of different orders, on all levels of the spatiotemporal hierarchy of the system under study as main information carriers. The tools to extract and analyze the information are power spectra and difference moments (structural functions) of various orders. Presently, FNS can be applied to three types of problems: (1) determination of parameters or patterns that characterize the dynamics or structural features of complex systems; (2) finding precursors of abrupt changes in the state of various ...

  3. Spectroscopy, Kinetics, and Dynamics of Combustion Radicals

    SciTech Connect (OSTI)

    Nesbitt, David J.

    2013-08-06

    Spectroscopy, kinetics and dynamics of jet cooled hydrocarbon transients relevant to the DOE combustion mission have been explored, exploiting i) high resolution IR lasers, ii) slit discharge sources for formation of jet cooled radicals, and iii) high sensitivity detection with direct laser absorption methods and near the quantum shot noise limit. What makes this combination powerful is that such transients can be made under high concentrations and pressures characteristic of actual combustion conditions, and yet with the resulting species rapidly cooled (T ?10-15K) in the slit supersonic expansion. Combined with the power of IR laser absorption methods, this provides novel access to spectral detection and study of many critical combustion species.

  4. Multiplex coherent raman spectroscopy detector and method

    DOE Patents [OSTI]

    Chen, Peter; Joyner, Candace C.; Patrick, Sheena T.; Guyer, Dean R.

    2004-06-08

    A multiplex coherent Raman spectrometer (10) and spectroscopy method rapidly detects and identifies individual components of a chemical mixture separated by a separation technique, such as gas chromatography. The spectrometer (10) and method accurately identify a variety of compounds because they produce the entire gas phase vibrational Raman spectrum of the unknown gas. This is accomplished by tilting a Raman cell (20) to produce a high-intensity, backward-stimulated, coherent Raman beam of 683 nm, which drives a degenerate optical parametric oscillator (28) to produce a broadband beam of 1100-1700 nm covering a range of more than 3000 wavenumber. This broadband beam is combined with a narrowband beam of 532 nm having a bandwidth of 0.003 wavenumbers and focused into a heated windowless cell (38) that receives gases separated by a gas chromatograph (40). The Raman radiation scattered from these gases is filtered and sent to a monochromator (50) with multichannel detection.

  5. Development of the charge exchange recombination spectroscopy and the beam emission spectroscopy on the EAST tokamak

    SciTech Connect (OSTI)

    Li, Y. Y.; Fu, J.; Lyu, B., E-mail: blu@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); Du, X. W.; Li, C. Y.; Yu, Y.; Wang, Q. P. [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026 (China); Zhang, Y.; Yin, X. H.; Ye, M. Y.; Wan, B. N. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, Anhui 230031 (China); School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026 (China); Hellermann, M. von [FOM-Institute for Plasma Physics “Rijnhuizen,” Association EURATOM, Trilateral Euregio Cluster, 3430BE Nieuwegein (Netherlands); Shi, Y. J. [School of Nuclear Science and Technology, University of Science and Technology of China, Hefei, Anhui 230026 (China); WCI for Fusion Theory, National Fusion Research Institute, 52 Eoeun-Dong, Yusung-Gu, Daejeon 305-333 (Korea, Republic of)

    2014-11-15

    Charge eXchange Recombination Spectroscopy (CXRS) and Beam Emission Spectroscopy (BES) diagnostics based on a heating neutral beam have recently been installed on EAST to provide local measurements of ion temperature, velocity, and density. The system design features common light collection optics for CXRS and BES, background channels for the toroidal views, multi-chord viewing sightlines, and high throughput lens-based spectrometers with good signal to noise ratio for high time resolution measurements. Additionally, two spectrometers each has a tunable grating to observe any wavelength of interest are used for the CXRS and one utilizes a fixed-wavelength grating to achieve higher diffraction efficiency for the BES system. A real-time wavelength correction is implemented to achieve a high-accuracy wavelength calibration. Alignment and calibration are performed. Initial performance test results are presented.

  6. Spectroscopy of Photovoltaic Materials: Charge-Transfer Complexes and Titanium Dioxide

    E-Print Network [OSTI]

    Dillon, Robert

    2013-01-01

    RIVERSIDE Spectroscopy of Photovoltaic Materials: Charge-DISSERTATION Spectroscopy of Photovoltaic Materials: Charge-function of photovoltaic (PV) and photocatalytic (PC)

  7. Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions

    SciTech Connect (OSTI)

    Bradforth, S.E.

    1992-11-01

    The transition state region of a neutral bimolecular reaction may be experimentally investigated by photoelectron spectroscopy of an appropriate negative ion. The photoelectron spectrum provides information on the spectroscopy and dynamics of the short lived transition state and may be used to develop model potential energy surfaces that are semi-quantitative in this important region. The principles of bound [yields] bound negative ion photoelectron spectroscopy are illustrated by way of an example: a full analysis of the photoelectron bands of CN[sup [minus

  8. Collinear laser spectroscopy of atomic cadmium

    E-Print Network [OSTI]

    Nadja Frömmgen; Dimiter L. Balabanski; Mark L. Bissell; Jacek Biero?; Klaus Blaum; Bradley Cheal; Kieran Flanagan; Stephan Fritzsche; Christopher Geppert; Michael Hammen; Magdalena Kowalska; Kim Kreim; Andreas Krieger; Rainer Neugart; Gerda Neyens; Mustafa M. Rajabali; Wilfried Nörtershäuser; Jasna Papuga; Deyan T. Yordanov

    2015-07-14

    Hyperfine structure $A$ and $B$ factors of the atomic $5s\\,5p\\,\\; ^3\\rm{P}_2 \\rightarrow 5s\\,6s\\,\\; ^3\\rm{S}_1$ transition are determined from collinear laser spectroscopy data of $^{107-123}$Cd and $^{111m-123m}$Cd. Nuclear magnetic moments and electric quadrupole moments are extracted using reference dipole moments and calculated electric field gradients, respectively. The hyperfine structure anomaly for isotopes with $s_{1/2}$ and $d_{5/2}$ nuclear ground states and isomeric $h_{11/2}$ states is evaluated and a linear relationship is observed for all nuclear states except $s_{1/2}$. This corresponds to the Moskowitz-Lombardi rule that was established in the mercury region of the nuclear chart but in the case of cadmium the slope is distinctively smaller than for mercury. In total four atomic and ionic levels were analyzed and all of them exhibit a similar behaviour. The electric field gradient for the atomic $5s\\,5p\\,\\; ^3\\mathrm{P}_2$ level is derived from multi-configuration Dirac-Hartree-Fock calculations in order to evaluate the spectroscopic nuclear quadrupole moments. The results are consistent with those obtained in an ionic transition and based on a similar calculation.

  9. Squeezed-light spin noise spectroscopy

    E-Print Network [OSTI]

    Lucivero, Vito Giovanni; Kong, Jia; Mitchell, Morgan W

    2015-01-01

    We report quantum enhancement of Faraday rotation spin noise spectroscopy by polarization squeezing of the probe beam. Using natural abundance Rb in \\SI{100}{Torr}of N$_2$ buffer gas, and squeezed light from a sub-threshold optical parametric oscillator stabilized \\SI{20}{GHz}to the blue of the D$_1$ resonance, we observe that an input squeezing of \\SI{3.0}{dB} improves the signal-to-noise ratio by \\SI{1.5}{dB} to \\SI{2.6}{dB} over the combined (power)$\\otimes$(number density) ranges (\\SI{0.5}{mW} to \\SI{4.0}{mW})$\\otimes$(\\SI{1.5d12}{cm\\tothe{-3}} to \\SI{1.3d13}{cm\\tothe{-3}}), covering the full practical range and into the strongly-perturbed regime. We show that in these conditions squeezing improves the trade-off between statistical noise and systematic shifts, a new kind of quantum advantage.

  10. Squeezed-light spin noise spectroscopy

    E-Print Network [OSTI]

    Vito Giovanni Lucivero; Ricardo Jiménez-Martínez; Jia Kong; Morgan W. Mitchell

    2015-09-18

    We report quantum enhancement of Faraday rotation spin noise spectroscopy by polarization squeezing of the probe beam. Using natural abundance Rb in \\SI{100}{Torr}of N$_2$ buffer gas, and squeezed light from a sub-threshold optical parametric oscillator stabilized \\SI{20}{GHz}to the blue of the D$_1$ resonance, we observe that an input squeezing of \\SI{3.0}{dB} improves the signal-to-noise ratio by \\SI{1.5}{dB} to \\SI{2.6}{dB} over the combined (power)$\\otimes$(number density) ranges (\\SI{0.5}{mW} to \\SI{4.0}{mW})$\\otimes$(\\SI{1.5d12}{cm\\tothe{-3}} to \\SI{1.3d13}{cm\\tothe{-3}}), covering the full practical range and into the strongly-perturbed regime. We show that in these conditions squeezing improves the trade-off between statistical noise and systematic shifts, a new kind of quantum advantage.

  11. High resolution spectroscopy of ultracool M dwarfs

    E-Print Network [OSTI]

    I. Neill Reid; J. Davy Kirkpatrick; J. Liebert; J. E. Gizis; C. C. Dahn; D. G. Monet

    2002-04-17

    (abridged) We present high-resolution echelle spectroscopy of a photometricaly-selected sample if thirty-nine dwarfs with spectral types between M6.5 and L0.5. Two stars, 2MASSI 0253202+271333 and 2MASSW 0952219-192431, are double-lined spectroscopic binaries. We have used our observations to search for Li I 6708 A absorption, characteristic of sub-stellar mass; estimate the level of chromospheric activity through measurement of H-alpha emission fluxes; measure rotational velocities via line broadening; and determine radial velocities and Galactic space motions. Two dwarfs have strong lithium absorption, the previously-known brown dwarf, LP 944-20, and 2MASSI J0335020+234235, which we identify as a probable 0.06 M_sun brown dwarf, age ~1 Gyr. We have investigated the prospect of using the observed frequency of lithium absorption amongst ultracool M dwarfs (M7 to M9.5) as a probe of the initial mass function. The available observations are difficult to reconcile with Salpeter-like power-law mass functions (alpha > 2) for masses below 0.1M_Sun. A comparison between the rotational velocities and -alpha fluxes shows no evidence for significant correlation. Velocity dispersions are significantly lower than those measured for nearby M dwarfs, but show remarkable similarity to results for earlier-type emission-line (dMe) dwarfs. The latter are generally assigned ages of less than ~3 Gyrs.

  12. Linear optics, Raman scattering, and spin noise spectroscopy

    E-Print Network [OSTI]

    Glazov, M M

    2015-01-01

    Spin noise spectroscopy (SNS) is a new method for studying magnetic resonance and spin dynamics based on measuring the Faraday rotation noise. In strong contrast with methods of nonlinear optics, the spectroscopy of spin noise is considered to be essentially nonperturbative. Presently, however, it became clear that the SNS, as an optical technique, demonstrates properties lying far beyond the bounds of conventional linear optics. Specifically, the SNS shows dependence of the signal on the light power density, makes it possible to penetrate inside an inhomogeneously broadened absorption band and to determine its homogeneous width, allows one to realize an effective pump-probe spectroscopy without any optical nonlinearity, etc. This may seem especially puzzling when taken into account that SNS can be considered just as a version of Raman spectroscopy, which is known to be deprived of such abilities. In this paper, we clarify this apparent inconsistency.

  13. Quantitative biological Raman spectroscopy for non-invasive blood analysis

    E-Print Network [OSTI]

    Shih, Wei-Chuan

    2007-01-01

    The long term goal of this project is the measurement of clinically-relevant analytes in the blood tissue matrix of human subjects using near-infrared Raman spectroscopy, with the shorter term research directed towards ...

  14. Early diagnosis of cancer using light scattering spectroscopy

    E-Print Network [OSTI]

    Backman, Vadim, 1973-

    2001-01-01

    This thesis presents a novel optical technique, light scattering spectroscopy (LSS), developed for quantitative characterization of tissue morphology as well as in vivo detection and diagnosis of the diseases associated ...

  15. Electrochemical Impedance Spectroscopy using adjustable nanometer-gap electrodes

    E-Print Network [OSTI]

    Ma, Hongshen, 1978-

    2007-01-01

    Electrochemical Impedance Spectroscopy (EIS) is a simple yet powerful chemical analysis technique for measuring the electrical permittivity and conductivity of liquids and gases. Presently, the limiting factor for using ...

  16. Surface enhanced Raman spectroscopy on a flat graphene surface

    E-Print Network [OSTI]

    Xu, Weigao

    Surface enhanced Raman spectroscopy (SERS) is an attractive analytical technique, which enables single-molecule sensitive detection and provides its special chemical fingerprints. During the past decades, researchers have ...

  17. Impedance Spectroscopy Systems Suitable for Biomedical Cell Impedance Measurement 

    E-Print Network [OSTI]

    Huang, Hao

    2013-06-03

    Impedance spectroscopy (IS) is an important technique for monitoring and detection of biomaterials. In order to enable point-of-care systems, low-cost IS systems capable of rapidly measuring a wide range of biomaterials ...

  18. Radio-frequency spectroscopy of ultracold atomic Fermi gases

    E-Print Network [OSTI]

    Schirotzek, Andre

    2010-01-01

    This thesis presents experiments investigating the phase diagram of ultracold atomic Fermi gases using radio-frequency spectroscopy. The tunability of many experimental parameters including the temperature, the interparticle ...

  19. Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy

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

    Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print Graphene-a single layer of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned...

  20. Photoinduced phase transitions studied by femtosecond single-shot spectroscopy

    E-Print Network [OSTI]

    Shin, Taeho

    2010-01-01

    Single-shot femtosecond spectroscopy has been developed and employed for the study of phase transitions of solid-state materials. Using two crossed echelons, a two dimensional spatial delay gradient was generated across a ...

  1. Crystallization Kinetics of Thermosensitive Colloids Probed by Transmission Spectroscopy

    E-Print Network [OSTI]

    Wu, Jianzhong

    Crystallization Kinetics of Thermosensitive Colloids Probed by Transmission Spectroscopy Shijun hard spheres, soft spheres, and PNIPAM spheres. Introduction Crystallization of colloidal systems systems.1-15 In recent years, colloidal crystals have been used extensively for the fabrication

  2. A first site of galaxy cluster formation: complete spectroscopy...

    Office of Scientific and Technical Information (OSTI)

    A first site of galaxy cluster formation: complete spectroscopy of a protocluster at z 6.01 Citation Details In-Document Search Title: A first site of galaxy cluster formation:...

  3. Detection of integrins using surface enhanced raman spectroscopy 

    E-Print Network [OSTI]

    Gant, Virgil Alexander

    2005-08-29

    changes of integrins on the surface of a cell maybe possible by developing a combined device such as an atomic force microscope (AFM) and surface enhanced Raman spectroscopy (SERS) system. However, the focus of this research is to first determine...

  4. Fourier Transform Infrared Spectroscopy for Process Monitoring and Control 

    E-Print Network [OSTI]

    Solomon, P. R.; Carangelo, M. D.; Carangelo, R. M.

    1994-01-01

    This paper discusses recent applications of FT-IR spectroscopy to measure gas concentrations and temperatures, and particle sizes. Advances in hardware are discussed and results for field tests in pulp and paper and utility boilers are presented....

  5. Staff Research Physicist (X-Ray Spectroscopy) | Princeton Plasma...

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

    position to work on X-ray spectroscopy, atomic physics, X-ray instrumentation, and high energy density physics. Near-term research goals include participating in the design,...

  6. Quenched hadron spectroscopy with improved staggered quark action

    E-Print Network [OSTI]

    MILC Collaboration; Claude Bernard; Tom Blum; Thomas A. DeGrand; Carleton DeTar; Steven Gottlieb; Urs M. Heller; James Hetrick; Craig McNeile; K. Rummukainen; Bob Sugar; Doug Toussaint

    1997-12-11

    We investigate light hadron spectroscopy with an improved quenched staggered quark action. We compare the results obtained with an improved gauge plus an improved quark action, an improved gauge plus standard quark action, and the standard gauge plus standard quark action. Most of the improvement in the spectroscopy results is due to the improved gauge sector. However, the improved quark action substantially reduces violations of Lorentz invariance, as evidenced by the meson dispersion relations.

  7. Mercury dimer spectroscopy and an Einstein-Podolsky-Rosen experiment 

    E-Print Network [OSTI]

    Qu, Xinmei

    2009-05-15

    SPECTROSCOPY AND AN EINSTEIN-PODOLSKY-ROSEN EXPERIMENT A Dissertation by XINMEI QU Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY... August 2008 Major Subject: Physics MERCURY DIMER SPECTROSCOPY AND AN EINSTEIN-PODOLSKY-ROSEN EXPERIMENT A Dissertation by XINMEI QU Submitted to the Office of Graduate Studies of Texas A&M University in partial...

  8. Chemical Shifts in X-ray and Photo-Electron Spectroscopy: A Historical review

    E-Print Network [OSTI]

    Lindgren, Ingvar

    Chemical Shifts in X-ray and Photo-Electron Spectroscopy: A Historical review Ingvar Lindgren 1 Introduction 2 2 Chemical shift in X-ray spectroscopy 2 2.1 Discovery of the chemical shift in X-ray spectroscopy . . . . . . . . . . . . . 3 2.2 Interpretation of the chemical shift in X-ray spectroscopy

  9. Exoplanet characterization with long slit spectroscopy

    E-Print Network [OSTI]

    Arthur Vigan; Maud Langlois; Claire Moutou; Kjetil Dohlen

    2008-08-28

    Extrasolar planets observation and characterization by high contrast imaging instruments is set to be a very important subject in observational astronomy. Dedicated instruments are being developed to achieve this goal with very high efficiency. In particular, full spectroscopic characterization of low temperature planetary companions is an extremely important milestone. We present a new data analysis method for long slit spectroscopy (LSS) with coronagraphy, which allows characterization of planetary companions of low effective temperature. In a speckle-limited regime, this method allows an accurate estimation and subtraction of the scattered starlight, to extract a clean spectrum of the planetary companion. We performed intensive LSS simulations with IDL/CAOS to obtain realistic spectra of low (R=35) and medium (R=400) resolution in the J, H, and K bands. The simulated spectra were used to test our method and estimate its performance in terms of contrast reduction and extracted spectra quality. Our simulations are based on a software package dedicated to the development of SPHERE, a second generation instrument for the ESO-VLT. Our method allows a contrast reduction of 0.5 to 2.0 magnitudes compared to the coronagraphic observations. For M0 and G0 stars located at 10 pc, we show that it would lead to the characterization of companions with Teff of 600 K and 900 K respectively, at angular separations of 1.0 as. We also show that errors in the wavelength calibration can produce significant errors in the characterization, and must therefore be minimized as much as possible.

  10. Magnetic spectroscopy and microscopy of functional materials

    SciTech Connect (OSTI)

    Jenkins, C.A.

    2011-01-28

    Heusler intermetallics Mn{sub 2}Y Ga and X{sub 2}MnGa (X; Y =Fe, Co, Ni) undergo tetragonal magnetostructural transitions that can result in half metallicity, magnetic shape memory, or the magnetocaloric effect. Understanding the magnetism and magnetic behavior in functional materials is often the most direct route to being able to optimize current materials for todays applications and to design novel ones for tomorrow. Synchrotron soft x-ray magnetic spectromicroscopy techniques are well suited to explore the the competing effects from the magnetization and the lattice parameters in these materials as they provide detailed element-, valence-, and site-specifc information on the coupling of crystallographic ordering and electronic structure as well as external parameters like temperature and pressure on the bonding and exchange. Fundamental work preparing the model systems of spintronic, multiferroic, and energy-related compositions is presented for context. The methodology of synchrotron spectroscopy is presented and applied to not only magnetic characterization but also of developing a systematic screening method for future examples of materials exhibiting any of the above effects. The chapter progression is as follows: an introduction to the concepts and materials under consideration (Chapter 1); an overview of sample preparation techniques and results, and the kinds of characterization methods employed (Chapter 2); spectro- and microscopic explorations of X{sub 2}MnGa/Ge (Chapter 3); spectroscopic investigations of the composition series Mn{sub 2}Y Ga to the logical Mn{sub 3}Ga endpoint (Chapter 4); and a summary and overview of upcoming work (Chapter 5). Appendices include the results of a Think Tank for the Graduate School of Excellence MAINZ (Appendix A) and details of an imaging project now in progress on magnetic reversal and domain wall observation in the classical Heusler material Co{sub 2}FeSi (Appendix B).

  11. TREE TRAILS Annual Benefits Breakdown

    E-Print Network [OSTI]

    side of a building can warm inside spaces. Trees slow down winds around buildings and help decrease heat loss. Find an animated model showing trees around a house at 1. http://treebenefits.com/calculator/ USDA Forest Service Center for Urban Forest Research http://www.fs.fed.us/psw/programs/uesd/uep/ Arbor

  12. 2012 ELECTRONIC SPECTROSCOPY & DYNAMICS GORDON RESEARCH CONFERENCE, JULY 22-27, 2012

    SciTech Connect (OSTI)

    Kohler, Bern

    2012-07-27

    Topics covered in this GRC include high-resolution spectroscopy, coherent electronic energy transport in biology, excited state theory and dynamics, excitonics, electronic spectroscopy of cold and ultracold molecules, and the spectroscopy of nanostructures. Several sessions will highlight innovative techniques such as time-resolved x-ray spectroscopy, frequency combs, and liquid microjet photoelectron spectroscopy that have forged stimulating new connections between gas-phase and condensed-phase work.

  13. Breakdown by magnetic field in a La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/MgO/Fe spin valve

    SciTech Connect (OSTI)

    Wu Xiaojie; Meng Jian [State Key Laboratory of Rare Earth Resources Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, 5625 Renmin Street, Changchun 130022 (China); Zhang Zhenzhong [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, 3888 Dongnanhu Road, Changchun 130033 (China)

    2012-03-19

    A La{sub 0.7}Sr{sub 0.3}MnO{sub 3}/MgO/Fe spin valve with inverse tunneling magnetoresistance (TMR) was fabricated on a (100) SrTiO{sub 3} substrate by radio frequency magnetron sputtering. Giant TMR ratios up to 540% were obtained. The breakdown of the spin valve was observed at high magnetic field, which was attributed to the joint action of the invalidation of MgO barrier and the shift of Fermi energy in La{sub 0.7}Sr{sub 0.3}MnO{sub 3} at high magnetic field.

  14. Study of asymmetries of Cd(Zn)Te devices investigated using photo-induced current transient spectroscopy, Rutherford backscattering, surface photo-voltage spectroscopy, and gamma ray spectroscopies

    SciTech Connect (OSTI)

    Crocco, J.; Bensalah, H.; Zheng, Q.; Dieguez, E.; Corregidor, V.; Avles, E.; Castaldini, A.; Fraboni, B.; Cavalcoli, D.; Cavallini, A.; Vela, O.

    2012-10-01

    Despite these recent advancements in preparing the surface of Cd(Zn)Te devices for detector applications, large asymmetries in the electronic properties of planar Cd(Zn)Te detectors are common. Furthermore, for the development of patterned electrode geometries, selection of each electrode surface is crucial for minimizing dark current in the device. This investigation presented here has been carried out with three objectives. Each objective is oriented towards establishing reliable methods for the selection of the anode and cathode surfaces independent of the crystallographic orientation. The objectives of this study are (i) investigate how the asymmetry in I-V characteristics of Cd(Zn)Te devices may be associated with the TeO2 interfacial layer using Rutherford backscattering to study the structure at the Au-Cd(Zn)Te interface, (ii) develop an understanding of how the concentration of the active traps in Cd(Zn)Te varies with the external bias, and (iii) propose non-destructive methods for selection of the anode and cathode which are independent of crystallographic orientation. The spectroscopic methods employed in this investigation include Rutherford backscattering spectroscopy, photo-induced current transient spectroscopy, and surface photo-voltage spectroscopy, as well as gamma ray spectroscopy to demonstrate the influence on detector properties.

  15. Femtosecond Coherent Anti-Stokes Raman Spectroscopy (CARS) As Next Generation Nonlinear LIDAR Spectroscopy and Microscopy

    SciTech Connect (OSTI)

    Ooi, C. H. Raymond

    2009-07-10

    Nonlinear spectroscopy using coherent anti-Stokes Raman scattering and femtosecond laser pulses has been successfully developed as powerful tools for chemical analysis and biological imaging. Recent developments show promising possibilities of incorporating CARS into LIDAR system for remote detection of molecular species in airborne particles. The corresponding theory is being developed to describe nonlinear scattering of a mesoscopic particle composed of complex molecules by laser pulses with arbitrary shape and spectral content. Microscopic many-body transform theory is used to compute the third order susceptibility for CARS in molecules with known absorption spectrum and vibrational modes. The theory is combined with an integral scattering formula and Mie-Lorentz formulae, giving a rigorous formalism which provides powerful numerical experimentation of CARS spectra, particularly on the variations with the laser parameters and the direction of detection.

  16. In Situ Diffuse Reflectance IR Spectroscopy and X-ray Absorption Spectroscopy for Fast Catalytic Processes

    SciTech Connect (OSTI)

    N Marinkovic; Q Wang; A Frenkel

    2011-12-31

    A new instrument for synchronous in situ investigations of catalytic materials by IR and X-ray absorption spectroscopies was designed and built at the X18A beamline of the National Synchrotron Light Source of Brookhaven National Laboratory. It provides analytical tools for solving structural, electronic and kinetic problems in catalysis science by two complementary methods. Among the features attractive for catalysis research are the broad range of catalytically active elements that can be investigated (starting with Ni and beyond), the wide range of reaction conditions (temperatures up to 873 K, various reactive gases) and time scales (starting from tens of seconds). The results of several representative experiments that illustrate the attractive capabilities of the new set-up are discussed.

  17. Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

    SciTech Connect (OSTI)

    Battaglieri, Marco; Briscoe, William; Celentano, Andrea; Chung, Suh-Urk; D'Angelo, Annalisa; De Vita, Rafaella; Döring, Michael; Dudek, Jozef; Eidelman, S.; Fegan, Stuart; Ferretti, J.; Filippi, A.; Fox, G.; Galata, G.; García-Tecocoatzi, H.; Glazier, Derek; Grube, B.; Hanhart, C.; Hoferichter, M.; Hughes, S. M.; Ireland, David G.; Ketzer, B.; Klein, Franz J.; Kubis, B.; Liu, B.; Masjuan, P.; Mathieu, Vincent; McKinnon, Brian; Mitchel, R.; Nerling, F.; Paul, S.; Peláez, J. R.; Rademacker, J.; Rizzo, Alessandro; Salgado, Carlos; Santopinto, E.; Sarantsev, Andrey V.; Sato, Toru; Schlüter, T.; da Silva, M. L.L.; Stankovic, I.; Strakovsky, Igor; Szczepaniak, Adam; Vassallo, A.; Walford, Natalie K.; Watts, Daniel P.

    2015-01-01

    The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopy in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.

  18. Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

    E-Print Network [OSTI]

    M. Battaglieri; B. J. Briscoe; A. Celentano; S. -U. Chung; A. D'Angelo; R. De Vita; M. Döring; J. Dudek; S. Eidelman; S. Fegan; J. Ferretti; A. Filippi; G. Fox; G. Galata; H. Garcia-Tecocoatzi; D. I. Glazier; B. Grube; C. Hanhart; M. Hoferichter; S. M. Hughes; D. G. Ireland; B. Ketzer; F. J. Klein; B. Kubis; B. Liu; P. Masjuan; V. Mathieu; B. McKinnon; R. Mitchell; F. Nerling; S. Paul; J. R. Pelaez; J. Rademacker; A. Rizzo; C. Salgado; E. Santopinto; A. V. Sarantsev; T. Sato; T. Schlüter; M. L. L. da Silva; I. Stankovic; I. Strakovsky; A. Szczepaniak; A. Vassallo; N. K. Walford; D. P. Watts; L. Zana

    2015-03-30

    The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopy in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.

  19. 2010 GRC VIBRATIONAL SPECTROSCOPY AUGUST 1 - AUGUST 6, 2010

    SciTech Connect (OSTI)

    Brooks Pate

    2010-08-06

    The Vibrational Spectroscopy conference focuses on using vibrational spectroscopy to probe structure and dynamics of molecules in gases, liquids, and at interfaces. The conference explores the wide range of state-of-the-art techniques based on vibrational motion. These techniques span the fields of time-domain, high-resolution frequency-domain, spatially-resolved, nonlinear and multidimensional spectroscopies. The conference highlights the application of these techniques in chemistry, materials, biology, and medicine. The theory of molecular vibrational motion and its connection to spectroscopic signatures and chemical reaction dynamics is the third major theme of the meeting. The goal is to bring together a collection of researchers who share common interests and who will gain from discussing work at the forefront of several connected areas. The intent is to emphasize the insights and understanding that studies of vibrations provide about a variety of molecular systems ranging from small polyatomic molecules to large biomolecules and nanomaterials.

  20. Single electron detection and spectroscopy via relativistic cyclotron radiation

    E-Print Network [OSTI]

    D. M. Asner; R. F. Bradley; L. de Viveiros; P. J. Doe; J. L. Fernandes; M. Fertl; E. C. Finn; J. A. Formaggio; D. Furse; A. M. Jones; J. N. Kofron; B. H. LaRoque; M. Leber; E. L. McBride; M. L. Miller; P. Mohanmurthy; B. Monreal; N. S. Oblath; R. G. H. Robertson; L. J Rosenberg; G. Rybka; D. Rysewyk; M. G. Sternberg; J. R. Tedeschi; T. Thummler; B. A. VanDevender; N. L. Woods

    2015-05-01

    It has been understood since 1897 that accelerating charges must emit electromagnetic radiation. Cyclotron radiation, the particular form of radiation emitted by an electron orbiting in a magnetic field, was first derived in 1904. Despite the simplicity of this concept, and the enormous utility of electron spectroscopy in nuclear and particle physics, single-electron cyclotron radiation has never been observed directly. Here we demonstrate single-electron detection in a novel radiofrequency spec- trometer. We observe the cyclotron radiation emitted by individual magnetically-trapped electrons that are produced with mildly-relativistic energies by a gaseous radioactive source. The relativistic shift in the cyclotron frequency permits a precise electron energy measurement. Precise beta elec- tron spectroscopy from gaseous radiation sources is a key technique in modern efforts to measure the neutrino mass via the tritium decay endpoint, and this work demonstrates a fundamentally new approach to precision beta spectroscopy for future neutrino mass experiments.

  1. Hyper-Ramsey spectroscopy of optical clock transitions

    SciTech Connect (OSTI)

    Yudin, V. I.; Taichenachev, A. V.; Oates, C. W.; Barber, Z. W.; Lemke, N. D.; Ludlow, A. D.; Sterr, U.; Lisdat, Ch.; Riehle, F. [Institute of Laser Physics, Siberian Branch of Russian Academy of Sciences, Novosibirsk 630090, Russia, Novosibirsk State University, Novosibirsk 630090, Russia, and Novosibirsk State Technical University, Novosibirsk 630092 (Russian Federation); National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305 (United States); Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116 Braunschweig (Germany)

    2010-07-15

    We present nonstandard optical Ramsey schemes that use pulses individually tailored in duration, phase, and frequency to cancel spurious frequency shifts related to the excitation itself. In particular, the field shifts and their uncertainties can be radically suppressed (by two to four orders of magnitude) in comparison with the usual Ramsey method (using two equal pulses) as well as with single-pulse Rabi spectroscopy. Atom interferometers and optical clocks based on two-photon transitions, heavily forbidden transitions, or magnetically induced spectroscopy could significantly benefit from this method. In the latter case, these frequency shifts can be suppressed considerably below a fractional level of 10{sup -17}. Moreover, our approach opens the door for high-precision optical clocks based on direct frequency comb spectroscopy.

  2. Infrared absorption spectroscopy and chemical kinetics of free radicals

    SciTech Connect (OSTI)

    Curl, R.F.; Glass, G.P. [Rice Univ., Houston, TX (United States)

    1993-12-01

    This research is directed at the detection, monitoring, and study of chemical kinetic behavior by infrared absorption spectroscopy of small free radical species thought to be important intermediates in combustion. During the last year, infrared kinetic spectroscopy using excimer laser flash photolysis and color-center laser probing has been employed to study the high resolution spectrum of HCCN, the rate constant of the reaction between ethynyl (C{sub 2}H) radical and H{sub 2} in the temperature region between 295 and 875 K, and the recombination rate of propargyl (CH{sub 2}CCH) at room temperature.

  3. Detection of Physiologically Relevant Alcohol Concentrations Using Raman Spectroscopy 

    E-Print Network [OSTI]

    McKay, Joshua L.

    2006-08-16

    . A. Watson, J. P. Wicksted, R. D. Stith, and W. F. March, ?Analysis of metabolites in aqueous solutions by using laser Raman spectroscopy,? Applied Optics, 32-6, 925-929, (1993). 5. A. J. Berger, Y. Wang, and M. S. Feld, ?Rapid, noninvasive... concentration measurements of aqueous biological analytes by near-infrared Raman spectroscopy,? Applied Optics, 35-1, 209-212, (1996). 29 6. A. J. Berger, I. Itzkan, and M. S. Feld, ?Feasibility of measuring blood glucose concentration by near...

  4. Spectroscopy and Decay of $B$ Hadrons at the Tevatron

    SciTech Connect (OSTI)

    Paulini, Manfred

    2007-02-01

    The authors review recent results on heavy quark physics focusing on Run II measurements of B hadron spectroscopy and decay at the Tevatron. A wealth of new B physics measurements from CDF and D0 has been available. These include the spectroscopy of excited B states (B**, B**{sub s}) and the observation of the {Sigma}{sub b} baryon. The discussion of the decays of B hadrons and measurements of branching fractions focuses on charmless two-body decays of B {yields} h{sup +}h{sup -}. They report several new B{sub s}{sup 0} and {Lambda}{sub b}{sup 0} decay channels.

  5. Development of Advanced Electrochemical Emission Spectroscopy for Monitoring Corrosion in Simulated DOE Liquid Waste

    SciTech Connect (OSTI)

    Digby D. Macdonald; Brian M. Marx; Sejin Ahn; Julio de Ruiz; Balaji Soundararaja; Morgan Smith; and Wendy Coulson

    2008-01-15

    Various forms of general and localized corrosion represent principal threats to the integrity of DOE liquid waste storage tanks. These tanks, which are of a single wall or double wall design, depending upon their age, are fabricated from welded carbon steel and contain a complex waste-form comprised of NaOH and NaNO{sub 3}, along with trace amounts of phosphate, sulfate, carbonate, and chloride. Because waste leakage can have a profound environmental impact, considerable interest exists in predicting the accumulation of corrosion damage, so as to more effectively schedule maintenance and repair. The different tasks that are being carried out under the current program are as follows: (1) Theoretical and experimental assessment of general corrosion of iron/steel in borate buffer solutions by using electrochemical impedance spectroscopy (EIS), ellipsometry and XPS techniques; (2) Development of a damage function analysis (DFA) which would help in predicting the accumulation of damage due to pitting corrosion in an environment prototypical of DOE liquid waste systems; (3) Experimental measurement of crack growth rate, acoustic emission signals and coupling currents for fracture in carbon and low alloy steels as functions of mechanical (stress intensity), chemical (conductivity), electrochemical (corrosion potential, ECP), and microstructural (grain size, precipitate size, etc) variables in a systematic manner, with particular attention being focused on the structure of the noise in the current and its correlation with the acoustic emissions; (4) Development of fracture mechanisms for carbon and low alloy steels that are consistent with the crack growth rate, coupling current data and acoustic emissions; (5) Inserting advanced crack growth rate models for SCC into existing deterministic codes for predicting the evolution of corrosion damage in DOE liquid waste storage tanks; (6) Computer simulation of the anodic and cathodic activity on the surface of the steel samples in order to exactly predict the corrosion mechanisms; (7) Wavelet analysis of EC noise data from steel samples undergoing corrosion in an environment similar to that of the high level waste storage containers, to extract data pertaining to general, pitting and stress corrosion processes, from the overall data. The Point Defect Model (PDM) is directly applied as the theoretical assessment method for describing the passive film formed on iron/steels. The PDM is used to describe general corrosion in the passive region of iron. In addition, previous work suggests that pit formation is due to the coalescence of cation vacancies at the metal/film interface which would make it possible to use the PDM parameters to predict the onset of pitting. This previous work suggests that once the critical vacancy density is reached, the film ruptures to form a pit. Based upon the kinetic parameters derived for the general corrosion case, two parameters relating to the cation vacancy formation and annihilation can be calculated. These two parameters can then be applied to predict the transition from general to pitting corrosion for iron/mild steels. If cation vacancy coalescence is shown to lead to pitting, it can have a profound effect on the direction of future studies involving the onset of pitting corrosion. The work has yielded a number of important findings, including an unequivocal demonstration of the role of chloride ion in passivity breakdown on nickel in terms of cation vacancy generation within the passive film, the first detection and characterization of individual micro fracture events in stress corrosion cracking, and the determination of kinetic parameters for the generation and annihilation of point defects in the passive film on iron. The existence of coupling between the internal crack environment and the external cathodic environment, as predicted by the coupled environment fracture model (CEFM), has also been indisputably established for the AISI 4340/NaOH system. It is evident from the studies that analysis of coupling current noise is a very sensitive tool f

  6. Development of Advanced Electrochemical Emission Spectroscopy for Monitoring Corrosion in Simulated DOE Liquid Waste

    SciTech Connect (OSTI)

    Digby Macdonald; Brian Marx; Balaji Soundararajan; Morgan Smith

    2005-07-28

    The different tasks that have been carried out under the current program are as follows: (1) Theoretical and experimental assessment of general corrosion of iron/steel in borate buffer solutions by using electrochemical impedance spectroscopy (EIS), ellipsometry and XPS techniques; (2) Development of a damage function analysis (DFA), which would help in predicting the accumulation of damage due to pitting corrosion in an environment prototypical of DOE liquid waste systems; (3) Experimental measurement of crack growth rate, acoustic emission signals, and coupling currents for fracture in carbon and low alloy steels as functions of mechanical (stress intensity), chemical (conductivity), electrochemical (corrosion potential, ECP), and microstructural (grain size, precipitate size, etc) variables in a systematic manner, with particular attention being focused on the structure of the noise in the current and its correlation with the acoustic emissions; (4) Development of fracture mechanisms for carbon and low alloy steels that are consistent with the crack growth rate, coupling current data and acoustic emissions; (5) Inserting advanced crack growth rate models for SCC into existing deterministic codes for predicting the evolution of corrosion damage in DOE liquid waste storage tanks; (6) Computer simulation of the anodic and cathodic activity on the surface of the steel samples in order to exactly predict the corrosion mechanisms; (7) Wavelet analysis of EC noise data from steel samples undergoing corrosion in an environment similar to that of the high level waste storage containers, to extract data pertaining to general, pitting and stress corrosion processes, from the overall data. The work has yielded a number of important findings, including an unequivocal demonstration of the role of chloride ion in passivity breakdown on nickel in terms of cation vacancy generation within the passive film, the first detection and characterization of individual micro fracture events in stress corrosion cracking, and the determination of kinetic parameters for the generation and annihilation of point defects in the passive film on iron. The existence of coupling between the internal crack environment and the external cathodic environment, as predicted by the coupled environment fracture model (CEFM), has also been indisputably established for the AISI 4340/NaOH system. It is evident from the studies that analysis of coupling current noise is a very sensitive tool for studying the crack tip processes in relation to the chemical, mechanical, electrochemical, and microstructural properties of the system. Experiments are currently being carried out to explore these crack tip processes by simultaneous measurement of the acoustic activity at the crack tip in an effort to validate the coupling current data. These latter data are now being used to deterministically predict the accumulation of general and localized corrosion damage on carbon in prototypical DOE liquid waste storage tanks. Computer simulation of the cathodic and anodic activity on the steel surfaces is also being carried out in an effort to simulate the actual corrosion process. Wavelet analysis of the coupling current data promises to be a useful tool to differentiate between the different corrosion mechanisms. Hence, wavelet analysis of the coupling current data from the DOE waste containers is also being carried out to extract data pertaining to general, pitting and stress corrosion processes, from the overall data which is bound to contain noise fluctuations due to any or all of the above mentioned processes.

  7. Radio frequency sheath formation and excitation around a stepped electrode

    SciTech Connect (OSTI)

    Barnat, E.V.; Hebner, G.A. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1423 (United States)

    2005-03-15

    Plasma and sheath structure around a rf excited stepped electrode is investigated. Laser-induced fluorescence dip spectroscopy is used to spatially resolve sheath fields in an argon discharge while optical emission and laser-induced fluorescence are used to measure the spatial structure of the surrounding discharge for various discharge conditions and step-junction configurations. The presence of the step perturbs the spatial structure of the fields around the step as well as the excitation in the region above the step.

  8. Wavelength modulation spectroscopy using novel mechanical light chopper blade designs

    E-Print Network [OSTI]

    Ghosh, Sandip

    Wavelength modulation spectroscopy using novel mechanical light chopper blade designs Jayeeta 23 May 2005; published online 21 July 2005 We describe two mechanical light chopper blade designs wavelength for positive grating orders. Our two designs, the alternating double-slot blade and the vertical

  9. New Frontiers in Solar Physics: Broadband Imaging Spectroscopy with the

    E-Print Network [OSTI]

    , the solar panel of the AASC recommended an integrated suite of instrumentation designed to meetNew Frontiers in Solar Physics: Broadband Imaging Spectroscopy with the Frequency Agile Solar and other astrophysical objects and processes. Outstanding problems in solar physics include the magnetic

  10. Amyloid Oligomer Formation Probed by Water Proton Magnetic Resonance Spectroscopy

    E-Print Network [OSTI]

    Berry, R. Stephen

    Amyloid Oligomer Formation Probed by Water Proton Magnetic Resonance Spectroscopy J. H. Walton, R, Chicago, Illinois; and § Department of Pharmacology, University of California, Davis, California ABSTRACT Formation of amyloid oligomers, the most toxic species of amyloids in degenerative diseases, is critically

  11. Analysis Tools for Next-Generation Hadron Spectroscopy Experiments

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

    Battaglieri, Marco; Briscoe, William; Celentano, Andrea; Chung, Suh-Urk; D'Angelo, Annalisa; De Vita, Rafaella; Döring, Michael; Dudek, Jozef; Eidelman, S.; Fegan, Stuart; et al

    2015-01-01

    The series of workshops on New Partial-Wave Analysis Tools for Next-Generation Hadron Spectroscopy Experiments was initiated with the ATHOS 2012 meeting, which took place in Camogli, Italy, June 20-22, 2012. It was followed by ATHOS 2013 in Kloster Seeon near Munich, Germany, May 21-24, 2013. The third, ATHOS3, meeting is planned for April 13-17, 2015 at The George Washington University Virginia Science and Technology Campus, USA. The workshops focus on the development of amplitude analysis tools for meson and baryon spectroscopy, and complement other programs in hadron spectroscopy organized in the recent past including the INT-JLab Workshop on Hadron Spectroscopymore »in Seattle in 2009, the International Workshop on Amplitude Analysis in Hadron Spectroscopy at the ECT*-Trento in 2011, the School on Amplitude Analysis in Modern Physics in Bad Honnef in 2011, the Jefferson Lab Advanced Study Institute Summer School in 2012, and the School on Concepts of Modern Amplitude Analysis Techniques in Flecken-Zechlin near Berlin in September 2013. The aim of this document is to summarize the discussions that took place at the ATHOS 2012 and ATHOS 2013 meetings. We do not attempt a comprehensive review of the field of amplitude analysis, but offer a collection of thoughts that we hope may lay the ground for such a document.« less

  12. Use of gamma spectroscopy for neutronic analysis of LMFBR Blankets

    E-Print Network [OSTI]

    Kang, Ch?ang-sun

    It was the purpose of the present investigation to extend and apply Ge(Li) gamma-ray spectroscopy to the study of fast reactor blankets. The focal point for this research was the Blanket Test Facility at the MITR and Blanket ...

  13. Charm and Charmonium Spectroscopy in BaBar

    SciTech Connect (OSTI)

    Negrini, M.; /Ferrara U.

    2008-02-06

    The BABAR experiment at the PEP-II B-factory offers excellent opportunities in charm and charmonium spectroscopy. The recent observation of new states in the D{sub s} and in the charmonium mass regions revived the interest in this field. Recent BABAR results are presented.

  14. Infrared Spectroscopy of Explosives Residues: Measurement Techniques and Spectral Analysis

    SciTech Connect (OSTI)

    Phillips, Mark C.; Bernacki, Bruce E.

    2015-03-11

    Infrared laser spectroscopy of explosives is a promising technique for standoff and non-contact detection applications. However, the interpretation of spectra obtained in typical standoff measurement configurations presents numerous challenges. Understanding the variability in observed spectra from explosives residues and particles is crucial for design and implementation of detection algorithms with high detection confidence and low false alarm probability. We discuss a series of infrared spectroscopic techniques applied toward measuring and interpreting the reflectance spectra obtained from explosives particles and residues. These techniques utilize the high spectral radiance, broad tuning range, rapid wavelength tuning, high scan reproducibility, and low noise of an external cavity quantum cascade laser (ECQCL) system developed at Pacific Northwest National Laboratory. The ECQCL source permits measurements in configurations which would be either impractical or overly time-consuming with broadband, incoherent infrared sources, and enables a combination of rapid measurement speed and high detection sensitivity. The spectroscopic methods employed include standoff hyperspectral reflectance imaging, quantitative measurements of diffuse reflectance spectra, reflection-absorption infrared spectroscopy, microscopic imaging and spectroscopy, and nano-scale imaging and spectroscopy. Measurements of explosives particles and residues reveal important factors affecting observed reflectance spectra, including measurement geometry, substrate on which the explosives are deposited, and morphological effects such as particle shape, size, orientation, and crystal structure.

  15. Thermal infrared emission spectroscopy of the pyroxene mineral series

    E-Print Network [OSTI]

    Hamilton, Victoria E.

    Thermal infrared emission spectroscopy of the pyroxene mineral series Victoria E. Hamilton within the two structural groups, as well as minerals within solid solution series. The exact number of reststrahlen features observed and their positions are dependent on mineral structure and cation occupancy

  16. Cysteine engineering of polyproteins for single-molecule force spectroscopy

    E-Print Network [OSTI]

    Dietz, Hendrik

    polyprotein construction. The basic concept of cysteine engineering of polyproteins is out- lined in Figure 1Cysteine engineering of polyproteins for single- molecule force spectroscopy Hendrik Dietz, Morten. We describe in detail the method to construct polyproteins with precisely controlled linkage

  17. Skin cancer detection by oblique-incidence diffuse reflectance spectroscopy 

    E-Print Network [OSTI]

    Smith, Elizabeth Brooks

    2009-05-15

    Skin cancer is the most common form of cancer and it is on the rise. If skin cancer is diagnosed early enough, the survival rate is close to 90%. Oblique-incidence diffuse reflectance (OIR) spectroscopy offers a technology that may be used...

  18. Spectroscopy of He 2 Floating on the Liquid Helium Surface

    E-Print Network [OSTI]

    Northby, Jan A.

    Spectroscopy of He 2 Floating on the Liquid Helium Surface Chih-Ching Hu, Raghuram Petluri, Jan A helium molecules produced in electron bombarded helium nanodroplets subsequently are detached by infrared highly sensitive detection of the absorption spectrum. Recent experiments utilize a new tunable infrared

  19. Postdoc Position in Microfluidics and Single Cell Raman Spectroscopy

    E-Print Network [OSTI]

    Horn, Matthias

    Postdoc Position in Microfluidics and Single Cell Raman Spectroscopy Department of Microbial and Environmental Microfluidics Group (http://web.mit.edu/romanstocker) Department of Civil & Environmental (junior or senior) with strong expertise in microfluidics and an interest in applying it to microbial

  20. Broadband microwave imaging spectroscopy with a solardedicated array

    E-Print Network [OSTI]

    Broad­band microwave imaging spectroscopy with a solar­dedicated array T.S. Bastian a , D.E. Gary b of Astronomy, University of Maryland, College Park, MD 20742 d Solar Astronomy 264­33, Caltech, Pasadena, CA the thermal structure of the solar atmosphere, and to study energy release and particle energization

  1. Multidimensional femtosecond spectroscopies of vibrational motions in liquids: Semiclassical expansion

    E-Print Network [OSTI]

    Mukamel, Shaul

    for nuclear wave packets, even when the system itself may be highly nonclassical. Two sources and vibrational anharmonicities--are identified. Formal analogy between the present equations and the time in nuclear magnetic resonance spectroscopy4 to provide invaluable information on the struc- ture and dynamics

  2. Pulsed laser Raman spectroscopy in the laser-heated diamond anvil...

    Office of Scientific and Technical Information (OSTI)

    Pulsed laser Raman spectroscopy in the laser-heated diamond anvil cell Citation Details In-Document Search Title: Pulsed laser Raman spectroscopy in the laser-heated diamond anvil...

  3. A computational approach to spectroscopy of molecular systems : modeling, prediction, and design

    E-Print Network [OSTI]

    Horning, Andrew D. (Andrew Davis)

    2015-01-01

    This thesis describes a series of approaches for modeling spectroscopy of molecular systems in aqueous environments, focusing on proton transfer, water dynamics, and hydrogen bonding interactions. The spectroscopy motivating ...

  4. X-Ray Spectroscopy of the Mn(4) Ca Cluster in the Water-Oxidation...

    Office of Scientific and Technical Information (OSTI)

    X-Ray Spectroscopy of the Mn(4) Ca Cluster in the Water-Oxidation Complex of Photosystem II Citation Details In-Document Search Title: X-Ray Spectroscopy of the Mn(4) Ca Cluster in...

  5. Development of multimodal spectroscopy for the detection of vulnerable atherosclerotic plaques

    E-Print Network [OSTI]

    Š?epanovi?, Obrad R., 1980-

    2008-01-01

    The combination of reflectance, fluorescence, and Raman spectroscopy - which is termed multimodal spectroscopy (MMS) - provides complementary and depth-sensitive information about tissue composition. As such, MMS can provide ...

  6. Geophysical applications of nuclear resonant spectroscopy Wolfgang Sturhahn and Jennifer M. Jackson*

    E-Print Network [OSTI]

    Jackson, Jennifer M.

    Geophysical applications of nuclear resonant spectroscopy Wolfgang Sturhahn and Jennifer M. Jackson summarize recent developments of nuclear resonant spectroscopy methods like nuclear resonant inelastic x important information on valence, spin state, and magnetic ordering. Both methods use a nuclear resonant

  7. In Operando Soft X-ray Spectroscopy of 3D Graphene Supercapacitor...

    Office of Scientific and Technical Information (OSTI)

    In Operando Soft X-ray Spectroscopy of 3D Graphene Supercapacitor Electrodes Citation Details In-Document Search Title: In Operando Soft X-ray Spectroscopy of 3D Graphene...

  8. The structure of langmuir monolayers probed with vibrational sum frequency spectroscopy 

    E-Print Network [OSTI]

    Gurau, Marc Cory

    2005-08-29

    structure have been examined with vibrational sum frequency spectroscopy (VSFS). This second order nonlinear optical spectroscopy is particularly well suited for simultaneous investigations of the monolayer and the associated water structure...

  9. Development of High-Throughput Microfluidic Impedance Spectroscopy Platform for Analyzing Microdroplets in Droplet Microfluidic System 

    E-Print Network [OSTI]

    Sobahi, Nebras MohammedKamal A.

    2014-07-22

    This thesis presents the development of a high-throughput microfluidic impedance spectroscopy platform for electrically detecting analyzing impedance measurements of non-contact and label free microdroplets. This microfluidic impedance spectroscopy...

  10. In situ characterization of soil properties using visible near-infrared diffuse reflectance spectroscopy 

    E-Print Network [OSTI]

    Waiser, Travis Heath

    2007-09-17

    Diffuse reflectance spectroscopy (DRS) is a rapid proximal-sensing method that is being used more and more in laboratory settings to measure soil properties. Diffuse reflectance spectroscopy research that has been completed in laboratories shows...

  11. Studies of the laser-induced fluorescence of explosives and explosive compositions.

    SciTech Connect (OSTI)

    Hargis, Philip Joseph, Jr.; Thorne, Lawrence R.; Phifer, Carol Celeste; Parmeter, John Ethan; Schmitt, Randal L.

    2006-10-01

    Continuing use of explosives by terrorists throughout the world has led to great interest in explosives detection technology, especially in technologies that have potential for standoff detection. This LDRD was undertaken in order to investigate the possible detection of explosive particulates at safe standoff distances in an attempt to identify vehicles that might contain large vehicle bombs (LVBs). The explosives investigated have included the common homogeneous or molecular explosives, 2,4,6-trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), cyclonite or hexogen (RDX), octogen (HMX), and the heterogeneous explosive, ammonium nitrate/fuel oil (ANFO), and its components. We have investigated standard excited/dispersed fluorescence, laser-excited prompt and delayed dispersed fluorescence using excitation wavelengths of 266 and 355 nm, the effects of polarization of the laser excitation light, and fluorescence imaging microscopy using 365- and 470-nm excitation. The four nitro-based, homogeneous explosives (TNT, PETN, RDX, and HMX) exhibit virtually no native fluorescence, but do exhibit quenching effects of varying magnitude when adsorbed on fluorescing surfaces. Ammonium nitrate and fuel oil mixtures fluoresce primarily due to the fuel oil, and, in some cases, due to the presence of hydrophobic coatings on ammonium nitrate prill or impurities in the ammonium nitrate itself. Pure ammonium nitrate shows no detectable fluorescence. These results are of scientific interest, but they provide little hope for the use of UV-excited fluorescence as a technique to perform safe standoff detection of adsorbed explosive particulates under real-world conditions with a useful degree of reliability.

  12. Dynamics of charge clouds ejected from laser-induced warm dense gold nanofilms

    SciTech Connect (OSTI)

    Zhou, Jun; Li, Junjie; Correa, Alfredo A.; Tang, Shao; Ping, Yuan; Ogitsu, Tadashi; Li, Dong; Zhou, Qiong; Cao, Jianming

    2014-10-24

    We report the first systematic study of the ejected charge dynamics surrounding laser-produced 30-nm warm dense gold films using single-shot femtosecond electron shadow imaging and deflectometry. The results reveal a two-step dynamical process of the ejected electrons under the high pump fluence conditions: an initial emission and accumulation of a large amount of electrons near the pumped surface region followed by the formation of hemispherical clouds of electrons on both sides of the film, which are escaping into the vacuum at a nearly isotropic and constant velocity with an unusually high kinetic energy of more than 300 eV. We also developed a model of the escaping charge distribution that not only reproduces the main features of the observed charge expansion dynamics but also allows us to extract the number of ejected electrons remaining in the cloud.

  13. Determining Pad-Wafer Contact using Dual Emission Laser Induced Fluorescence Caprice Gray1

    E-Print Network [OSTI]

    White, Robert D.

    energy required to break and re-order the chemical bonds on the glass substrate surface so thickness, asperity layer compressibility, surface roughness measurements and polishing pad rebound

  14. Nanosecond laser-induced phase transitions in pulsed laser deposition-deposited GeTe films

    SciTech Connect (OSTI)

    Sun, Xinxing, E-mail: xinxing.sun@iom-leipzig.de; Thelander, Erik; Lorenz, Pierre; Gerlach, Jürgen W.; Decker, Ulrich; Rauschenbach, Bernd [Leibniz Institute of Surface Modification, Permoserstr. 15, D-04318, Leipzig (Germany)

    2014-10-07

    Phase transformations between amorphous and crystalline states induced by irradiation of pulsed laser deposition grown GeTe thin films with nanosecond laser pulses at 248 nm and pulse duration of 20 ns are studied. Structural and optical properties of the Ge-Te phase-change films were studied by X-ray diffraction and optical reflectivity measurements as a function of the number of laser pulses between 0 and 30 pulses and of the laser fluence up to 195 mJ/cm². A reversible phase transition by using pulse numbers ? 5 at a fluence above the threshold fluence between 11 and 14 mJ/cm² for crystallization and single pulses at a fluence between 162 and 182 mJ/cm² for amorphization could be proved. For laser fluences from 36 up to 130 mJ/cm², a high optical contrast of 14.7% between the amorphous and crystalline state is measured. A simple model is used that allows the discussion on the distribution of temperature in dependency on the laser fluence.

  15. Laser-induced short time scale thermal chemistry of perfluoropolyether lubricant films

    SciTech Connect (OSTI)

    Heller, J.; Mate, C.J.; Poon, C.C.; Tam, A.C.

    1999-11-09

    The authors investigate the effect of heating a perfluoropolyether lubricant film in a localized area for relatively short time periods using laser irradiation versus conventional oven heating. These experiments help provide understanding on how flash temperatures generated at frictional contacts affect the thermal chemistry of lubricant films. In these experiments, a CO{sub 2} laser heats a 50 {micro}m wide area of a silicon wafer for time periods ranging from 0.1 to 60 s. The surface temperature within the heated area (up to 280 C in these experiments) is monitored with a second laser by measuring the change in reflectivity near the center of the heated area. A major difference observed for laser heating compared to oven heating is that the effective evaporation rate is orders of magnitude higher for laser heating. If the lubricant film is heated for sufficiently long enough time at high temperatures, the authors are able to observe thermal bonding of the lubricant via its alcohol end groups to the silicon oxide surface, followed by thermal decomposition of the lubricant molecules. After laser heating, the authors are able to observe the diffusion of lubricant back into the localized heated area using a combination of optical microscopy and imaging ellipsometry.

  16. Local Investigation of Femtosecond Laser Induced Dynamics of Water Nanoclusters on Cu(111) Michael Mehlhorn,1

    E-Print Network [OSTI]

    Alavi, Ali

    .37.Ef, 68.43.Bc, 82.30.Rs, 82.53.St There is broad interest in supported water-ice and the mechanims

  17. Laser desorption ionization and peptide sequencing on laser induced silicon microcolumn arrays

    DOE Patents [OSTI]

    Vertes, Akos (Reston, VA); Chen, Yong (San Diego, CA)

    2011-12-27

    The present invention provides a method of producing a laser-patterned silicon surface, especially silicon wafers for use in laser desorption ionization (LDI-MS) (including MALDI-MS and SELDI-MS), devices containing the same, and methods of testing samples employing the same. The surface is prepared by subjecting a silicon substrate to multiple laser shots from a high-power picosecond or femtosecond laser while in a processing environment, e.g., underwater, and generates a remarkable homogenous microcolumn array capable of providing an improved substrate for LDI-MS.

  18. Femtosecond laser-induced formation of submicrometer spikes on a semiconductor substrate

    DOE Patents [OSTI]

    Mazur, Eric; Shen, Mengyan

    2013-12-03

    The present invention generally provides a semiconductor substrates having submicron-sized surface features generated by irradiating the surface with ultra short laser pulses. In one aspect, a method of processing a semiconductor substrate is disclosed that includes placing at least a portion of a surface of the substrate in contact with a fluid, and exposing that surface portion to one or more femtosecond pulses so as to modify the topography of that portion. The modification can include, e.g., generating a plurality of submicron-sized spikes in an upper layer of the surface.

  19. Laser-induced ultrafast electron emission from a field emission tip

    E-Print Network [OSTI]

    Brett Barwick; Chris Corder; James Strohaber; Nate Chandler-Smith; Cornelis Uiterwaal; Herman Batelaan

    2007-03-08

    We show that a field emission tip electron source that is triggered with a femtosecond laser pulse can generate electron pulses shorter than the laser pulse duration (~100 fs). The emission process is sensitive to a power law of the laser intensity, which supports an emission mechanism based on multiphoton absorption followed by over-the-barrier emission. Observed continuous transitions between power laws of different orders are indicative of field emission processes. We show that the source can also be operated so that thermionic emission processes become significant. Understanding these different emission processes is relevant for the production of sub-cycle electron pulses.

  20. Laser-induced photoelectrochemistry on n- and p-InP electrodes

    SciTech Connect (OSTI)

    Cook, R.L.; Dempsey, P.F.; Sammells, A.F.

    1986-09-01

    Time-resolved laser pulse photoelectrochemical and forward current measurements were performed on p-InP/ aqueous electrolyte interfaces as a function of the electrolyte (1M KOH and 1M HCIO/sub 4/) and etch pretreatment (12M HCl or 6:1:1:1:HNO/sub 3/:HCl:CH/sub 3/COOH:HClO/sub 4/). Such measurements show that etch pretreatment may affect carrier transfer mechanisms at the interface but had little effect on the barrier height. Barrier heights in 1M HClO/sub 4/ were ..beta..200 mV larger than in 1M KOH. Photopotential decay after laser pulse excitation was found to follow a (time)/sup -2/3/ dependence. A linear relationship was also found by plotting (% full laser intensity)/sup 5/3/ vs. slope of the t/sup -2/3/ curves indicating that relaxation of the semiconductor depletion region contributes to the observed time dependency of the transient photopotential. Analysis of the photopotential decay data by plotting ln((exp(Ep(t=o))-1)/(exp(Ep(t))-1)) vs. time suggest that carrier tr4apping may be important at the p-lnP/electrolyte interface and the 6:1:1:1 etch pretreatment may be more effective than 12M HCl in reducing the trap density.

  1. Laser-induced separation of hydrogen isotopes in the liquid phase

    DOE Patents [OSTI]

    Freund, Samuel M. (Los Alamos, NM); Maier, II, William B. (Los Alamos, NM); Beattie, Willard H. (Los Alamos, NM); Holland, Redus F. (Los Alamos, NM)

    1980-01-01

    Hydrogen isotope separation is achieved by either (a) dissolving a hydrogen-bearing feedstock compound in a liquid solvent, or (b) liquefying a hydrogen-bearing feedstock compound, the liquid phase thus resulting being kept at a temperature at which spectral features of the feedstock relating to a particular hydrogen isotope are resolved, i.e., a clear-cut isotope shift is delineated, irradiating the liquid phase with monochromatic radiation of a wavelength which at least preferentially excites those molecules of the feedstock containing a first hydrogen isotope, inducing photochemical reaction in the excited molecules, and separating the reaction product containing the first isotope from the liquid phase.

  2. High Spatial Resolution Laser Cavity Extinction and Laser Induced Incandescence in Low Soot Producing Flames

    E-Print Network [OSTI]

    Tian, B.; Gao, Y.; Balusamy, S.; Hochgreb, S.

    2015-06-26

    1 Introduction Soot particles generated from combustion are both a significant atmo- spheric pollutant, as well as a contributor to climate change [1–4]. Many techniques have therefore been developed to measure soot particles from a variety... ,34] is that the present technique does not rely on pulsed, shot-to-shot measurements, but rather a low power, low cost CW laser. This allows for a much simpler, less expensive system, which does not require a fast response detector and signal receiver capable of nanosec...

  3. Ultrafast Laser Induced Thermo-Elasto-Visco-Plastodynamics in Single Crystalline Silicon 

    E-Print Network [OSTI]

    Qi, Xuele

    2011-02-22

    A comprehensive model for describing the fundamental mechanism dictating the interaction of ultrafast laser pulse with single crystalline silicon wafer is formulated. The need for establishing the feasibility of employing lasers of subpicosecond...

  4. Aerosol Mass Spectrometry via Laser-Induced Incandescence Particle Vaporization Final Report

    SciTech Connect (OSTI)

    Timothy B. Onasch

    2011-10-20

    We have successfully developed and commercialized a soot particle aerosol mass spectrometer (SP-AMS) instrument to measure mass, size, and chemical information of soot particles in ambient environments. The SP-AMS instrument has been calibrated and extensively tested in the laboratory and during initial field studies. The first instrument paper describing the SP-AMS has been submitted for publication in a peer reviewed journal and there are several related papers covering initial field studies and laboratory studies that are in preparation. We have currently sold 5 SP-AMS instruments (either as complete systems or as SP modules to existing AMS instrument operators).

  5. Effect of temperature and CO2 concentration on laser-induced...

    Office of Scientific and Technical Information (OSTI)

    (LIBS) was used in the evaluation of aerosol concentration in the exhaust of an oxygennatural-gas glass furnace. Experiments showed that for a delay time of 10 micros and a...

  6. Femtosecond laser-induced formation of submicrometer spikes on a semiconductor substrate

    DOE Patents [OSTI]

    Mazur, Eric (Concord, MA); Shen, Mengyan (Arlington, MA)

    2008-10-28

    The present invention generally provides semiconductor substrates having submicron-sized surface features generated by irradiating the surface with ultra short laser pulses. In one aspect, a method of processing a semiconductor substrate is disclosed that includes placing at least a portion of a surface of the substrate in contact with a fluid, and exposing that surface portion to one or more femtosecond pulses so as to modify the topography of that portion. The modification can include, e.g., generating a plurality of submicron-sized spikes in an upper layer of the surface.

  7. Time-Dependent Ion Velocity Distribution: A novel Heterodyne Laser-Induced Fluorescence with Coupled

    E-Print Network [OSTI]

    with Coupled Wave Excitation IEPC-2013-239 Presented at the 33rd International Electric Propulsion Conference Physics Laboratory, adiallo@pppl.gov 1 The 33rd International Electric Propulsion Conference, The George in the power consumption of commercial spacecrafts. The physics governing these oscillations which in turn lead

  8. Laser induced reentrant freezing in two-dimensional attractive colloidal systems

    E-Print Network [OSTI]

    Pinaki Chaudhuri; Chinmay Das; Chandan Dasgupta; H. R. Krishnamurthy; A. K. Sood

    2005-09-11

    The effects of an externally applied one-dimensional periodic potential on the freezing/melting behaviour of two-dimensional systems of colloidal particles with a short-range attractive interaction are studied using Monte Carlo simulations. In such systems, incommensuration results when the periodicity of the external potential does not match the length-scale at which the minimum of the attractive potential occurs. To study the effects of this incommensuration, we consider two different models for the system. Our simulations for both these models show the phenomenon of reentrant freezing as the strength of the periodic potential is varied. Our simulations also show that different exotic phases can form when the strength of the periodic potential is high, depending on the length-scale at which the minimum of the attractive pair-potential occurs.

  9. Pump probe imaging of nanosecond laser induced bubbles in agar gel

    E-Print Network [OSTI]

    Aguilar, Guillermo

    .0000) General. References and links 1. A. Brujan and A. Vogel, "Stress wave emission and cavitation bubble lysis: Time-resolved imaging and analysis of hydrodynamic effects," Biophysical Journal 91

  10. Laser-induced fluorescence fiber optic probe measurement of oil dilution by fuel

    DOE Patents [OSTI]

    Parks, II, James E [Knoxville, TN; Partridge, Jr., William P [Oak Ridge, TN

    2010-11-23

    Apparatus for detecting fuel in oil includes an excitation light source in optical communication with an oil sample for exposing the oil sample to excitation light in order to excite the oil sample from a non-excited state to an excited state and a spectrally selective device in optical communication with the oil sample for detecting light emitted from the oil sample as the oil sample returns from the excited state to a non-excited state to produce spectral indicia that can be analyzed to determine the presence of fuel in the oil sample. A method of detecting fuel in oil includes the steps of exposing a oil sample to excitation light in order to excite the oil sample from a non-excited state to an excited state, as the oil sample returns from the excited state to a non-excited state, detecting light emitted from the oil sample to produce spectral indicia; and analyzing the spectral indicia to determine the presence of fuel in the oil sample.

  11. Effect of Surface Charge on Laser-induced Neutral Atom Desorption

    SciTech Connect (OSTI)

    Beck, Kenneth M.; Joly, Alan G.; Hess, Wayne P.

    2010-10-01

    When an ionic metal oxide crystal is cleaved, inhomogeneous electrical charging of the surface can be a result. Such an effect has been well-documented in magnesium oxide (100). For example, recent rigorous AFM studies indicate that nanoscale charged clusters of MgO are created during cleavage, with high concentrations often located at terrace step edges.[1] In addition, ablation processes of freshly cleaved magnesium oxide crystals may be effected by remnant surface charging and microstructures.[2] We report here that such surface charging strongly impacts even neutral atom desorption, even under conditions of extremely mild excitation of surface terrace features. In our experiments, single crystal MgO (100) is cleaved in air and placed in an ultra-high vacuum chamber (UHV). We irradiate the crystal at 6.4 eV, photon energy resonant with five-coordinated (5-C) terrace sites and probe desorbing neutral oxygen atoms. It is found that a significant fraction of desorbed neutral oxygen atoms from the charged surface possess kinetic energies in excess of 0.7 eV. This is in contrast to uncharged samples (discharged in vacuo over 24 hours) that display a near-thermal oxygen atom distribution.

  12. Dynamics of charge clouds ejected from laser-induced warm dense gold nanofilms

    SciTech Connect (OSTI)

    Zhou, Jun; Li, Junjie; Correa, Alfredo A.; Tang, Shao; Ping, Yuan; Ogitsu, Tadashi; Li, Dong; Zhou, Qiong; Cao, Jianming

    2014-10-24

    We report the first systematic study of the ejected charge dynamics surrounding laser-produced 30- nm warm dense gold films using single-shot femtosecond electron shadow imaging and deflectometry. The results reveal a two-step dynamical process of the ejected electrons under the high pump fluence conditions: an initial emission and accumulation of a large amount of electrons near the pumped surface region followed by the formation of hemispherical clouds of electrons on both sides of the film, which are escaping into the vacuum at a nearly isotropic and constant velocity with an unusually high kinetic energy of more than 300 eV. We also developed a model of the escaping charge distribution that not only reproduces the main features of the observed charge expansion dynamics but also allows us to extract the number of ejected electrons remaining in the cloud.

  13. Determination of population, alignment, and orientation using laser induced fluorescence with unresolved emission

    E-Print Network [OSTI]

    with unresolved emission Andrew C. Kummel, Greg O. Sitz, and Richard N. Zare Department ofChemistry, Stanford expressions are evaluated for the case in which the emission is unresolved and collected independent ofits polarization and for the case in which the emission is unresolved but is analyzed with a polarizer. When

  14. Laser induced modulation of the Landau level structure in single-layer graphene

    E-Print Network [OSTI]

    Alexander Lopez; Antonio Di Teodoro; John Schliemann; Bertrand Berche; Benjamin Santos

    2015-07-30

    We present perturbative analytical results of the Landau level quasienergy spectrum, autocorrelation function and out of plane pseudospin polarization for a single graphene sheet subject to intense circularly polarized terahertz radiation. For the quasienergy spectrum, we find a striking non trivial level-dependent dynamically induced gap structure. This photoinduced modulation of the energy band structure gives rise to shifts of the revival times in the autocorrelation function and it also leads to modulation of the oscillations in the dynamical evolution of the out of plane pseudospin polarization, which measures the angular momentum transfer between light and graphene electrons. For a coherent state, chosen as an initial pseudospin configuration, the dynamics induces additional quantum revivals of the wave function that manifest as shifts of the maxima and minima of the autocorrelation function, with additional partial revivals and beating patterns. These additional maxima and beating patterns stem from the effective dynamical coupling of the static eigenstates. We discuss the possible experimental detection schemes of our theoretical results and their relevance in new practical implementation of radiation fields in graphene physics.

  15. DETECTION OF ULTRA-TRACE LEVELS OF URANIUM IN AQUEOUS SAMPLES BY LASER INDUCED FLUORESCENCE SPECTROMETRY

    E-Print Network [OSTI]

    Perry, Dale L.

    2012-01-01

    deposits (especially around nuclear waste repositories) requires rapid, high sensitive analytical techniques. Hydrogeochemical exploration for uranium

  16. Temporal femtosecond pulse shaping dependence of laser-induced periodic surface structures in fused silica

    SciTech Connect (OSTI)

    Shi, Xuesong; Jiang, Lan; Li, Xin, E-mail: lixin02@bit.edu.cn; Zhang, Kaihu; Yu, Dong; Yu, Yanwu [NanoManufacturing Fundamental Research Joint Laboratory of National Science Foundation of China, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081 (China); Lu, Yongfeng [Department of Electrical Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska 68588-0511 (United States)

    2014-07-21

    The dependence of periodic structures and ablated areas on temporal pulse shaping is studied upon irradiation of fused silica by femtosecond laser triple-pulse trains. Three types of periodic structures can be obtained by using pulse trains with designed pulse delays, in which the three-dimensional nanopillar arrays with ?100–150?nm diameters and ?200?nm heights are first fabricated in one step. These nanopillars arise from the break of the ridges of ripples in the upper portion, which is caused by the split of orthogonal ripples in the bottom part. The localized transient electron dynamics and corresponding material properties are considered for the morphological observations.

  17. Laser-induced acoustic wave generation/propagation/interaction in water in various internal channels

    E-Print Network [OSTI]

    2010-01-01

    induced plane acoustic wave generation, propagation andinduced acoustic wave generation/propagation/interaction insingle acoustic wave generation, propagation, interaction

  18. New method for measuring low NO concentrations using laser induced two photon ionization

    E-Print Network [OSTI]

    Lee, Shan-Hu

    and Technology, The University of Tokyo, Komaba 4-6-1, Meguro, Tokyo 153, Japan Received 28 January 1997 resulting from the D 2 X 2 transition was de- tected. Since the fluorescence occurs near 190 nm, a wave- length region free from laser generated background noise, signal-limited SL measurement conditions

  19. Barium Ion Extraction and Identification from Laser Induced Fluorescence in Gas for the

    E-Print Network [OSTI]

    Wechsler, Risa H.

    is increasingly interested in neutrinoless double beta decay. A potential measurement of the decay rate would neutrinoless double beta decay experiments, especially if the neutrino mass is low. This thesis describes three of a gas phase detector for a neutrinoless double beta decay measurement. It has been determined

  20. Generation of laser-induced cavitation bubbles with a digital hologram

    E-Print Network [OSTI]

    Quinto-Su, P. A; Venugopalan, V.; Ohl, C.-D.

    2008-01-01

    in which a high power light emitting diode (LED, model P7,of a high power light emitting diode (LED) and a current

  1. DEVELOPMENT OF LASER-INDUCED FLUORESCENCE DIAGNOSTIC FOR THE PAUL TRAP SIMULATOR EXPERIMENT

    E-Print Network [OSTI]

    Gilson, Erik

    scientific research in high energy and nuclear physics, to applications such as spallation neutron sources, ion-beam-driven high energy density physics, and nuclear waste transmutation, to mention a few [1 with initial test results. Research supported by the U.S. Department of Energy mchung@princeton.edu BARIUM

  2. Femtosecond laser-induced formation of submicrometer spikes on a semiconductor substrate

    DOE Patents [OSTI]

    Mazur, Eric (Concord, MA), Shen; Mengyan (Belmont, MA)

    2011-02-08

    The present invention generally provides semiconductor substrates having submicron-sized surface features generated by irradiating the surface with ultra short laser pulses. In one aspect, a method of processing a semiconductor substrate is disclosed that includes placing at least a portion of a surface of the substrate in contact with a fluid, and exposing that surface portion to one or more femtosecond pulses so as to modify the topography of that portion. The modification can include, e.g., generating a plurality of submicron-sized spikes in an upper layer of the surface.

  3. Dynamics of charge clouds ejected from laser-induced warm dense gold nanofilms

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

    Zhou, Jun; Li, Junjie; Correa, Alfredo A.; Tang, Shao; Ping, Yuan; Ogitsu, Tadashi; Li, Dong; Zhou, Qiong; Cao, Jianming

    2014-10-24

    We report the first systematic study of the ejected charge dynamics surrounding laser-produced 30-nm warm dense gold films using single-shot femtosecond electron shadow imaging and deflectometry. The results reveal a two-step dynamical process of the ejected electrons under the high pump fluence conditions: an initial emission and accumulation of a large amount of electrons near the pumped surface region followed by the formation of hemispherical clouds of electrons on both sides of the film, which are escaping into the vacuum at a nearly isotropic and constant velocity with an unusually high kinetic energy of more than 300 eV. We alsomore »developed a model of the escaping charge distribution that not only reproduces the main features of the observed charge expansion dynamics but also allows us to extract the number of ejected electrons remaining in the cloud.« less

  4. Determination of the transient electron temperature in a femtosecond-laser-induced air plasma filament

    SciTech Connect (OSTI)

    Sun Zhanliang; Chen Jinhai; Rudolph, Wolfgang

    2011-04-15

    The transient electron temperature in a weakly ionized femtosecond-laser-produced air plasma filament was determined from optical absorption and diffraction experiments. The electron temperature and plasma density decay on similar time scales of a few hundred picoseconds. Comparison with plasma theory reveals the importance of inelastic collisions that lead to energy transfer to vibrational degrees of freedom of air molecules during the plasma cooling.

  5. Ion Dynamics in a Single and Dual Radio Frequency Sheath Measured by Laser-Induced Fluorescence

    E-Print Network [OSTI]

    Moore, Nathaniel Breckenridge

    2015-01-01

    at the 56 th APS Division of Plasma Physics meeting, Newat the 55 th APS Division of Plasma Physics meeting, Denver,

  6. Non-linear photochemical pathways in laser induced atmospheric aerosol formation

    E-Print Network [OSTI]

    Mongin, Denis; Schubert, Elise; Brisset, Jean-Gabriel; Berti, Nicolas; Moret, Michel; Prévôt, André S H; Baltensperger, Urs; Kasparian, Jérôme; Wolf, Jean-Pierre

    2015-01-01

    We measured the chemical composition and the size distribution of aerosols generated by femtosecond-Terawatt laser pulses in the atmosphere using an aerosol mass spectrometer (AMS). We show that nitric acid condenses in the form of ammonium nitrate, and that oxidized volatile organics also contribute to particle growth. These two components account for two thirds and one third, respectively, of the dry laser-condensed mass. They appear in two different modes centred at 380 nm and 150 nm. The number concentration of particles between 25 and 300 nm increases by a factor of 15. Pre-existing water droplets strongly increase the oxidative properties of the laser-activated atmosphere, substantially enhancing the condensation of organics under laser illumination.

  7. Mechanical failure characterization of optical components caused by laser induced damage initiated at contaminants

    SciTech Connect (OSTI)

    Faux, D. R., LLNL

    1997-12-01

    The goal of this research is to quantify by numerical techniques the effects of surface and subsurface absorbing defects on damage initiation and growth in high power laser optical components. The defects include laser absorbing spots (e.g., surface particulate contamination) and surface damage regions (e.g., micro-cracks and voids) which are present due to environmental exposure and fabrication processes. This report focuses on three sources of contamination that can cause damage to optical components: (1) Front surface particle contamination, (2) Back surface particle contamination, and (3) Subsurface particle contamination. The DYNA2D (non-linear structural mechanics) code was used to model the growth of damage in the glass substrate. The damage in the nominally transparent glass substrate as a result of front surface particle contamination was found to be dependent on the magnitude of the resultant pressure pulse applied to the particle and the initial area of contact between the particle and glass substrate. The pressures generated from a back surface particle being blown off the surface provided sufficient loading to severely damage (crack) the glass substrate. A subsurface Ceria dioxide particle showed a strong surface interaction that influenced the formation and direction of the damage (cracking) that ultimately resulted in the blow-out of the damaged material leaving a relatively clean crater in the glass. Crater shape and size was determined. Since fused silica is the most transparent, and therefore laser damage resistant, of the optical materials, it is used for the most at-risk optical elements. The present studies are for a fused silica substrate. Some oxides such as Ceria are transparent in the infrared and visible, but absorbing in the UV part of the spectrum. Because ICF lasers like NIF use frequency tripling, effects of such oxides must be included.

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

    Office of Scientific and Technical Information (OSTI)

    C; Colvin, J; Gammon, S; Jaquez, J; Satcher, J; Fournier, K B 70 PLASMA PHYSICS AND FUSION Abstract not provided Lawrence Livermore National Laboratory (LLNL), Livermore, CA...

  9. Laser induced electron acceleration in a tapered magnetic wiggler K. P. Singha)

    E-Print Network [OSTI]

    Singh, Kunwar Pal

    is the dephasing of the trapped electron with respect to the driver laser wave. As the electron energy increases Department of Physics, Indian Institute of Technology, New Delhi-110016, India Received 8 July 2003; accepted is satisfied and energy gained by the electron increases. The resonance condition is sensitive to the electron

  10. Numerical and experimental investigation of laser induced tube bending Wenchuan Li andY. Lawrence Yao

    E-Print Network [OSTI]

    Yao, Y. Lawrence

    normally requires repeated annealing when mechanical bending is used. Silve, et a!. investigated procedures for laser bending ofsquare cross-section tubes ofmild steel1 · Different scanning sequences were compared

  11. Laser Induced Nuclear Physics and Applications K.W.D. Ledingham,

    E-Print Network [OSTI]

    Strathclyde, University of

    receiving an injection of a pharmaceutical labeled with a short-lived + emitting source which collects used radio- pharmaceutical is 2-fluoro-2-deoxyglucose 2-[18 F]FDG. Over the last few years the value of PET FDG in the management of cancer patients has been widely demonstrated. Figure 1 highlights

  12. Ion Dynamics in a Single and Dual Radio Frequency Sheath Measured by Laser-Induced Fluorescence

    E-Print Network [OSTI]

    Moore, Nathaniel Breckenridge

    2015-01-01

    and phase resolved ion energy and ion angular distributions27 FIGURE 2.6. Ion energy distribution functions in a dual52 FIGURE 5.2. Example vertical ion energy distribution

  13. Soft x-ray free-electron laser induced damage to inorganic scintillators

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

    Burian, Tomáš; Hájková, V?ra; Chalupský, Jaromír; Vyšín, Lud?k; Bohá?ek, Pavel; P?e?ek, Martin; Wild, Jan; Özkan, Cigdem; Coppola, Nicola; Farahani, Shafagh Dastjani; et al

    2015-01-07

    An irreversible response of inorganic scintillators to intense soft x-ray laser radiation was investigated at the FLASH (Free-electron LASer in Hamburg) facility. Three ionic crystals, namely, Ce:YAG (cerium-doped yttrium aluminum garnet), PbWO4 (lead tungstate), and ZnO (zinc oxide), were exposed to single 4.6 nm ultra-short laser pulses of variable pulse energy (up to 12 ?J) under normal incidence conditions with tight focus. Damaged areas produced with various levels of pulse fluences, were analyzed on the surface of irradiated samples using differential interference contrast (DIC) and atomic force microscopy (AFM). The effective beam area of 22.2 ± 2.2 ?m2 was determinedmore »by means of the ablation imprints method with the use of poly(methyl methacrylate) - PMMA. Applied to the three inorganic materials, this procedure gave almost the same values of an effective area. The single-shot damage threshold fluence was determined for each of these inorganic materials. The Ce:YAG sample seems to be the most radiation resistant under the given irradiation conditions, its damage threshold was determined to be as high as 660.8 ± 71.2 mJ/cm2. Contrary to that, the PbWO4 sample exhibited the lowest radiation resistance with a threshold fluence of 62.6 ± 11.9 mJ/cm2. The threshold for ZnO was found to be 167.8 ± 30.8 mJ/cm2. Both interaction and material characteristics responsible for the damage threshold difference are discussed in the article.« less

  14. Quantitative planar laser-induced fluorescence imaging of multi-component

    Office of Scientific and Technical Information (OSTI)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantity of NaturalDukeWakefieldSulfateSciTech ConnectSpeedingConnect Pulse energy measurement(Conference) | SciTechfuel/air

  15. I CALCULATIONS ON ISOTOPE SEPARATION BY LASER INDUCED PHOTODISSOCIATION OF POLYATOMIC MOLECULES

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverse (JournalvivoHighHussein KhalilResearch &ENERGY I NFRASTRUCTURE - _-f; . I

  16. Protein Characterisation by Synchrotron Radiation Circular Dichroism (SRCD) Spectroscopy

    SciTech Connect (OSTI)

    Wallace, B.

    2009-01-01

    Circular dichroism (CD) spectroscopy is a well-established technique for the study of proteins. Synchrotron radiation circular dichroism (SRCD) spectroscopy extends the utility of conventional CD spectroscopy (i.e. using laboratory-based instruments) because the high light flux from a synchrotron enables collection of data to lower wavelengths, detection of spectra with higher signal-to-noise levels and measurements in the presence of strongly absorbing non-chiral components such as salts, buffers, lipids and detergents. This review describes developments in instrumentation, methodologies and bioinformatics that have enabled new applications of the SRCD technique for the study of proteins. It includes examples of the use of SRCD spectroscopy for providing static and dynamic structural information on molecules, including determinations of secondary structures of intact proteins and domains, assessment of protein stability, detection of conformational changes associated with ligand and drug binding, monitoring of environmental effects, examination of the processes of protein folding and membrane insertion, comparisons of mutant and modified proteins, identification of intermolecular interactions and complex formation, determination of the dispositions of proteins in membranes, identification of natively disordered proteins and their binding partners and examination of the carbohydrate components of glycoproteins. It also discusses how SRCD can be used in conjunction with macromolecular crystallography and other biophysical techniques to provide a more complete picture of protein structures and functions, including how proteins interact with other macromolecules and ligands. This review also includes a discussion of potential new applications in structural and functional genomics using SRCD spectroscopy and future instrumentation and bioinformatics developments that will enable such studies. Finally, the appendix describes a number of computational/bioinformatics resources for secondary structure analyses that take advantage of the improved data quality available from SRCD. In summary, this review discusses how SRCD can be used for a wide range of structural and functional studies of proteins.

  17. X-ray line polarization spectroscopy of Li-like satellite line...

    Office of Scientific and Technical Information (OSTI)

    United States Language: English Subject: 74; ANISOTROPY; DISTRIBUTION FUNCTIONS; ELECTRONS; KINETICS; LASERS; PLASMA; POLARIZATION; PULSES; SATELLITES; SPECTRA; SPECTROSCOPY...

  18. Ion dip spectroscopy of cold molecules and ions. Progress report and renewal proposal

    SciTech Connect (OSTI)

    Wessel, J.

    1987-08-13

    A research program is underway with the objective of developing techniques of high resolution multiphoton spectroscopy for selective, ultrasensitive molecular detection. Methods under study include various forms of ion dip spectroscopy and new methods of ion fragmentation spectroscopy. The studies are providing a new understanding of the fundamental spectroscopy and photophysics of large molecular ions. Dimer and cluster ions of polynuclear aromatics and related species are also being investigated, with potential detection applications.

  19. Discrepancies between isotope ratio infrared spectroscopy and isotope ratio mass spectrometry for the

    E-Print Network [OSTI]

    Goldsmith, Greg

    -axis integrated cavity output spectroscopy (OA-ICOS, Los Gatos Research) and wavelength-scanned cavity ring

  20. Photoelectron Spectroscopy under Ambient Pressure and Temperature Conditions

    SciTech Connect (OSTI)

    Ogletree, D. Frank; Bluhm, Hendrik; Hebenstreit, Eleonore B.; Salmeron, Miquel

    2009-02-27

    We describe the development and applications of novel instrumentation for photoemission spectroscopy of solid or liquid surfaces in the presence of gases under ambient conditions or pressure and temperature. The new instrument overcomes the strong scattering of electrons in gases by the use of an aperture close to the surface followed by a differentially-pumped electrostatic lens system. In addition to the scattering problem, experiments in the presence of condensed water or other liquids require the development of special sample holders to provide localized cooling. We discuss the first two generations of Ambient Pressure PhotoEmission Spectroscopy (APPES) instruments developed at synchrotron light sources (ALS in Berkeley and BESSY in Berlin), with special focus on the Berkeley instruments. Applications to environmental science and catalytic chemical research are illustrated in two examples.