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Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
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1

Ultrafast thin-film laser-induced breakdown spectroscopy of doped...  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast thin-film laser-induced breakdown spectroscopy of doped oxides Title Ultrafast thin-film laser-induced breakdown spectroscopy of doped oxides Publication Type Journal...

2

Double pulse laser induced breakdown spectroscopy; experimental study of  

NLE Websites -- All DOE Office Websites (Extended Search)

Double pulse laser induced breakdown spectroscopy; experimental study of Double pulse laser induced breakdown spectroscopy; experimental study of lead emission intensity dependence on the wavelengths and sample matrix Title Double pulse laser induced breakdown spectroscopy; experimental study of lead emission intensity dependence on the wavelengths and sample matrix Publication Type Journal Article Year of Publication 2009 Authors Piscitelli, Vincent, Mauro A. Martinez, Alberto J. Fernandez, Jhanis J. Gonzalez, Xianglei Mao, and Richard E. Russo Journal Spectrochimica Acta Part B Volume 64 Issue 2 Pagination 147-154 Date Published 02/2009 Keywords Double pulse LIBS, laser induced breakdown spectroscopy, lead Abstract Lead (Pb) emission intensity (atomic line 405.78 nm) dependence on the sample matrix (metal alloy) was studied by means of collinear double pulse (DP)-laser induced breakdown spectroscopy (LIBS). The measurement of the emission intensity produced by three different wavelength combinations (i.e. I:532 nm-II:1064 nm, I:532 nm-II:532 nm, and I:532 nm-II:355 nm) from three series of standard reference materials showed that the lead atomic line 405.78 nm emission intensity was dependent on the sample matrix for all the combination of wavelengths, however reduced dependency was found for the wavelength combination I:532 nm-II:355 nm.

3

Ultrafast laser induced breakdown spectroscopy of electrode/electrolyte  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast laser induced breakdown spectroscopy of electrode/electrolyte Ultrafast laser induced breakdown spectroscopy of electrode/electrolyte interfaces Title Ultrafast laser induced breakdown spectroscopy of electrode/electrolyte interfaces Publication Type Journal Article Year of Publication 2012 Authors Zormpa, Vasileia, Jaroslaw Syzdek, Xianglei Mao, Richard E. Russo, and Robert Kostecki Journal Applied Physics Letters Volume 100 Issue 23 Date Published 05-2012 ISSN 0003-6951 Keywords electrochemical electrodes, graphite, high-speed optical techniques, laser beam effects, organic compounds, pyrolysis, solid electrolytes Abstract Direct chemical analysis of electrode/electrolyte interfaces can provide critical information on surface phenomena that define and control the performance of Li-based battery systems. In this work, we introduce the use of ex situ femtosecond laser induced breakdown spectroscopy to probe compositional variations within the solid electrolyte interphase (SEI) layer. Nanometer-scale depth resolution was achieved for elemental and molecular depth profiling of SEI layers formed on highly oriented pyrolytic graphite electrodes in an organic carbonate-based electrolyte. This work demonstrates the unique ability of ultrafast laser spectroscopy as a highly versatile, light element-sensitive technique for direct chemical analysis of interfacial layers in electrochemical energy storage systems.

4

Laser-Induced Breakdown Spectroscopy Research Facility  

LIBS Research User Facility is focused on collaborative research in laser spark spectroscopy, laser ablation, and the development of techniques for application to ...

5

Laser-induced breakdown spectroscopy as a diagnostic tool for coal fines.  

E-Print Network (OSTI)

??Laser Induced Breakdown Spectroscopy (LIBS) is a technique that uses a laser, to focus down and atomize a sample of desired material. Focusing of the… (more)

Aurelio, I. Andrew.

2005-01-01T23:59:59.000Z

6

Elemental analysis of slurry samples with laser induced breakdown spectroscopy  

Science Conference Proceedings (OSTI)

Direct analysis of wet slurry samples with laser induced breakdown spectroscopy (LIBS) is challenging due to problems of sedimentation, splashing, and surface turbulence. Also, water can quench the laser plasma and suppress the LIBS signal, resulting in poor sensitivity. The effect of water on LIBS spectra from slurries was investigated. As the water content decreased, the LIBS signal was enhanced and the standard deviation was reduced. To improve LIBS slurry analysis, dried slurry samples prepared by applying slurry on PVC coated slides were evaluated. Univariate and multivariate calibration was performed on the LIBS spectra of the dried slurry samples for elemental analysis of Mg, Si, and Fe. Calibration results show that the dried slurry samples give a good correlation between spectral intensity and elemental concentration.

Eseller, Kemal E.; Tripathi, Markandey M.; Yueh, Fang-Yu; Singh, Jagdish P.

2010-05-01T23:59:59.000Z

7

Development of laser induced breakdown spectroscopy instrumentatin for safeguards applications  

DOE Green Energy (OSTI)

In September 2006, a Technical Meeting on Application of Laser Spectrometry Techniques in IAEA Safeguards was held at IAEA headquarters (HQ). One of the principal recommendations from this meeting was the need to 'pursue the development of novel complementary access instrumentation based on laser induced breakdown spectroscopy (LIBS) for the detection of gaseous and solid signatures and indicators of nuclear fuel cycle processes and associated materials.' Pursuant to this recommendation the Department of Safeguards (SG) under the Division of Technical Support (SGTS) convened the Experts and Users Advisory Meeting on Laser Induced Breakdown Spectroscopy (LIBS) for Safeguards Applications. This meeting was held at IAEA HQ from July 7-11,2008 and hosted by the Novel Technologies Unit (NTU). The meeting was attended by 12 LIBS experts from the Czech Republic, the European Commission, France, the Republic of Korea, the United States of America, Germany, the United Kingdom of Great Britain, Canada, and Northern Ireland. After a presentation of the needs of the IAEA inspectors, the LIBS experts were in agreement that needs as presented could be partially or fully fulfilled using LIBS instrumentation. The needs of the IAEA inspectors were grouped in the following broad categories: (1) Improvements to in-field measurements/environmental sampling; (2) Monitoring status of activity in a Hot Cell; (3) Verifying status of activity at a declared facility via process monitoring; and (4) Need for pre-screening of environmental samples before analysis. Under the Department of Energy/National Nuclear Security Administration (DOE/NNSA) Next Generation Safeguards Initiative (NGSI) Los Alamos National Laboratory is exploring three potential applications of LIBS for international safeguards. As part of this work, we are developing: (1) a user-friendly man-portable LIBS system to characterize samples across a wide range of elements in the periodic table from hydrogen up to heavy elements like plutonium and uranium; (2) a LIBS system that can be deployed in harsh environments such as gloveboxes and hot cells providing relative compositional analysis of process streams for example ratios like Cm/Pu and Cm/U; and (3) an inspector field deployable system that can be used to analyze the elemental composition of microscopic quantities of samples containing plutonium and uranium. In this paper we will describe our current development and performance testing results both in a fixed lab and measurements in field deployable configurations using LIBS instrumentation developed for applications to international safeguards.

Barefield Il, James E [Los Alamos National Laboratory; Clegg, Samuel M [Los Alamos National Laboratory; Le, Loan A [Los Alamos National Laboratory; Lopez, Leon N [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

8

Laser-Induced Breakdown Spectroscopy System Using a Passively Q-Switched Laser  

NLE Websites -- All DOE Office Websites (Extended Search)

Laser-Induced Breakdown Spectroscopy System Laser-Induced Breakdown Spectroscopy System Using a Passively Q-Switched Laser Opportunity Research is active on the patent-pending technology, titled "Laser-Induced Breakdown Spectroscopy (LIBS) System Using a Passively Q-Switched Laser." This technology is available for licensing and/or further collaborative research from the U.S. Department of Energy's National Energy Technology Laboratory. Overview Atomic spectroscopy systems such as LIBS are used in many applications where the elemental composition of a solid, liquid or gas sample is desired. In addition, this detection technology has the advantage of providing composition data without sample destruction. In LIBS systems, precise timing and control between the laser and the spectrometer detector are

9

Detection of trace phosphorus in steel using laser-induced breakdown spectroscopy combined with laser-induced fluorescence  

Science Conference Proceedings (OSTI)

Monitoring of light-element concentration in steel is very important for quality assurance in the steel industry. In this work, detection in open air of trace phosphorus (P) in steel using laser-induced breakdown spectroscopy (LIBS) combined with laser-induced fluorescence (LIF) has been investigated. An optical parametric oscillator wavelength-tunable laser was used to resonantly excite the P atoms within plasma plumes generated by a Q-switched Nd:YAG laser. A set of steel samples with P concentrations from 3.9 to 720 parts in 10{sup 6}(ppm) were analyzed using LIBS-LIF at wavelengths of 253.40 and 253.56 nm for resonant excitation of P atoms and fluorescence lines at wavelengths of 213.55 and 213.62 nm. The calibration curves were measured to determine the limit of detection for P in steel, which is estimated to be around 0.7 ppm. The results demonstrate the potential of LIBS-LIF to meet the requirements for on-line analyses in open air in the steel industry.

Shen, X. K.; Wang, H.; Xie, Z. Q.; Gao, Y.; Ling, H.; Lu, Y. F.

2009-05-01T23:59:59.000Z

10

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

Science Conference Proceedings (OSTI)

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.

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

2008-11-01T23:59:59.000Z

11

Laser-induced breakdown spectroscopy at high temperatures in industrial boilers and furnaces.  

DOE Green Energy (OSTI)

Laser-induced breakdown spectroscopy (LIBS) was applied (1) near the superheater of an electric power generation boiler burning biomass, coat, or both, (2) at the exit of a glass-melting furnace burning natural gas and oxygen, and (3) near the nose arches of two paper mill recovery boilers burning black liquor. Difficulties associated with the high temperatures and high particle loadings in these environments were surmounted by use of novel LIBS probes. Echelle and linear spectrometers coupled to intensified CCD cameras were used individually and sometimes simultaneously. Elements detected include Na, K, Ca, Mg, C, B, Si, Mn, Al, Fe, Rb, Cl, and Ti.

Walsh, Peter M. (University of Alabama at Birmingham and Southern Research Institute, Birmingham, AL); Shaddix, Christopher R.; Sickafoose, Shane M.; Blevins, Linda Gail

2003-02-01T23:59:59.000Z

12

Guided conversion to enhance cation detection in water using laser-induced breakdown spectroscopy  

Science Conference Proceedings (OSTI)

A novel approach, named guided conversion enhancement, has been established to improve the laser-induced breakdown spectroscopy (LIBS) sensitivity of cation detection in water. Two processes were involved in this approach: the main part was replacement reaction that converted the cations in water to solid granules on the surface of an immersed metallic sheet; the other was electric assistance that increased local cation concentration and strengthened the reaction. With the aid of replacement reaction and an electric field, a detection limit of 16 ppb was achieved for copper cation (Cu{sup 2+}) detection in a water solution of CuSO4. The obtained results suggest that this approach has significant potential to be developed as an effective method for underwater cation detection.

Lu Yuan; Li Ying; Wu Jianglai; Zhong Shilei; Zheng Ronger

2010-05-01T23:59:59.000Z

13

Evaluation of factors affecting the analysis of metals using laser-induced breakdown spectroscopy  

SciTech Connect

Some of the main factors affecting the analysis of solid steel using laser-induced break-down spectroscopy (LIBS) have been investigated and are reported here. Pulses from an electro-optically Q-switched Nd:YAG laser were focused on steel samples to generate a high temperature plasma. The spectrally resolved plasma light was time resolved and detected using a photodiode array. The effects that changes in the lens-to-sample distance, laser pulse energy, and position of the imaging lens had on the LIBS analysis are described. These effects were minimized by ratioing the absolute element signals to adjacent Fe-lines. Calibration curves for Mn, Si, and Cr are presented and the accuracy and precision of LIBS analysis listed for several elements. 12 refs.

Cremers, D.A.; Romero, D.J.

1986-01-01T23:59:59.000Z

14

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

SciTech Connect

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.

Tyler L. Westover

2013-01-01T23:59:59.000Z

15

Analysis of indium zinc oxide thin films by laser-induced breakdown spectroscopy  

Science Conference Proceedings (OSTI)

We have performed spectroscopic analysis of the plasma generated by Nd:YAG ({lambda} = 266 nm) laser irradiation of thin indium zinc oxide films with variable In content deposited by combinatorial pulsed laser deposition on glass substrates. The samples were irradiated in 5 x 10{sup 4} Pa argon using laser pulses of 5 ns duration and 10 mJ energy. The plasma emission spectra were recorded with an Echelle spectrometer coupled to a gated detector with different delays with respect to the laser pulse. The relative concentrations of indium and zinc were evaluated by comparing the measured spectra to the spectral radiance computed for a plasma in local thermal equilibrium. Plasma temperature and electron density were deduced from the relative intensities and Stark broadening of spectral lines of atomic zinc. Analyses at different locations on the deposited thin films revealed that the In/(In + Zn) concentration ratio significantly varies over the sample surface, from 0.4 at the borders to about 0.5 in the center of the film. The results demonstrate that laser-induced breakdown spectroscopy allows for precise and fast characterization of thin films with variable composition.

Popescu, A. C. [LP3, CNRS - Universite Aix-Marseille, 163 Ave. de Luminy, Marseille 13288 (France); National Institute for Lasers, Plasma and Radiation Physics, Magurele, Ilfov 077125 (Romania); Beldjilali, S. [LP3, CNRS - Universite Aix-Marseille, 163 Ave. de Luminy, Marseille 13288 (France); LPPMCA, Universite des Sciences et de la Technologie d'Oran, BP 1505 El Mnaouer, Oran (Algeria); Socol, G.; Mihailescu, I. N. [National Institute for Lasers, Plasma and Radiation Physics, Magurele, Ilfov 077125 (Romania); Craciun, V. [National Institute for Lasers, Plasma and Radiation Physics, Magurele, Ilfov 077125 (Romania); MAIC, University of Florida, Gainesville, FL 32611 (United States); Hermann, J. [LP3, CNRS - Universite Aix-Marseille, 163 Ave. de Luminy, Marseille 13288 (France)

2011-10-15T23:59:59.000Z

16

Micro-Crater Laser Induced Breakdown Spectroscopy--an Analytical approach in metals samples  

Science Conference Proceedings (OSTI)

The laser ablation has been increasing its popularity like as technique of chemical analysis. This is due to its great potentiality in the analysis of solid samples. On the way to contributing to the development of the technique, we in this work studied the laser induced breakdown spectroscopy (LIBS) in conditions of micro ablation for future studies of coverings and micro crates analysis. Craters between 2 and 7 micrometers of diameter were made using an Nd-YAG nanosecond laser in their fundamental emission of 1064 nm. In order to create these craters we use an objective lens of long distance work and 0.45 of numerical aperture. The atomic emission versus the energy of the laser and its effect on the size of craters was study. We found that below 3 micrometers although there was evidence of material removal by the formation of a crater, it was no detectable atomic emission for our instruments. In order to try to understand this, curves of size of crater versus plasma temperature using the Boltzmann distribution graphs taking the Copper emission lines in the visible region were made. In addition calibration curves for Copper and aluminum were made in two different matrices; one of it was a Cu/Zn alloy and the other a Zinc Matrix. The atomic lines Cu I (521.78 nm) and Al I (396.15 nm) was used. From the Calibration curve the analytical limit of detection and other analytical parameters were obtained.

Piscitelli, Vincent [UCV- Laboratorio de Espectroscopia Laser, Caracas (Venezuela); Lawrence Berkeley National laboratory, Berkeley, US (United States); Gonzalez, Jhanis; Mao Xianglei; Russo, Richard [Lawrence Berkeley National laboratory, Berkeley, US (United States); Fernandez, Alberto [UCV- Laboratorio de Espectroscopia Laser, Caracas (Venezuela)

2008-04-15T23:59:59.000Z

17

Program on Technology Innovation: Feasibility of Laser-Induced Breakdown Spectroscopy for Fuel Analysis—Phase II  

Science Conference Proceedings (OSTI)

In the first phase of this project, researchers evaluated the capabilities of laser-induced breakdown spectroscopy (LIBS) for fuel characterization in gasification applications. A LIBS system was assembled and optimized to identify and measure the elemental spectra from the following gasifier feedstocks: bituminous coal, lignite coal, and petroleum coke, including three blends of coal and pet coke as well as coal treated with limestone. Laboratory LIBS data were acquired and processed using artificial ne...

2011-12-30T23:59:59.000Z

18

Total Carbon Measurement in Soils Using Laser-Induced Breakdown Spectroscopy: Results from the Field and Implications for Carbon Sequestration  

NLE Websites -- All DOE Office Websites (Extended Search)

Total Carbon Measurement in Soils using Laser-Induced Breakdown Total Carbon Measurement in Soils using Laser-Induced Breakdown Spectroscopy: Results from the Field and Implications for Carbon Sequestration Michael H. Ebinger (mhe@lanl.gov, 505-667-3147) Environmental Dynamics and Spatial Analysis Group (EES-10), MS J495 Earth and Environmental Sciences Division Los Alamos National Laboratory, Los Alamos, NM 87545, USA. David A. Cremers (cremers_david@lanl.gov, 505-665-4180) Advanced Chemical Diagnostics and Instrumentation Group, MS J565 Chemistry Division Los Alamos National Laboratory, Los Alamos, NM 87545 David D. Breshears (daveb@lanl.gov, 505-665-2803) Environmental Dynamics and Spatial Analysis Group (EES-10), MS J495 Earth and Environmental Sciences Division Los Alamos National Laboratory, Los Alamos, NM 87545, USA.

19

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

DOE Green Energy (OSTI)

Advanced methodologies and improvements to current measurements techniques are needed to strengthen the effectiveness and efficiency of international safeguards. This need was recognized and discussed at a Technical Meeting on 'The Application of Laser Spectrometry Techniques in IAEA Safeguards' held at IAEA headquarters (September 2006). One of the principal recommendations from that meeting was the need to pursue the development of novel complementary access instrumentation based on Laser Induced Breakdown Spectroscopy (UBS) for the detection of gaseous and solid signatures and indicators of nuclear fuel cycle processes and associated materials'. Pursuant to this recommendation the Department of Safeguards (SG) under the Division of Technical Support (SGTS) convened the 'Experts and Users Advisory Meeting on Laser Induced Breakdown Spectroscopy (LIBS) for Safeguards Applications' also held at IAEA headquarters (July 2008). This meeting was attended by 12 LlBS experts from the Czech Republic, the European Commission, France, the Republic of South Korea, the United States of America, Germany, the United Kingdom of Great Britain, Canada, and Northern Ireland. Following a presentation of the needs of the IAEA inspectors, the LIBS experts agreed that needs as presented could be partially or fully fulfilled using LIBS instrumentation. Inspectors needs were grouped into the following broad categories: (1) Improvements to in-field measurements/environmental sampling; (2) Monitoring status of activities in Hot Cells; (3) Verify status of activity at a declared facility via process monitoring; and (4) Need for pre-screening of environmental samples before analysis. The primary tool employed by the IAEA to detect undeclared processes and activities at special nuclear material facilities and sites is environmental sampling. One of the objectives of the Next Generation Safeguards Initiative (NGSI) Program Plan calls for the development of advanced tools and methodologies to detect and analyze undeclared processing or production of special nuclear material. Los Alamos National Laboratory is currently investigating potential uses of LIBS for safeguards applications, including (1) a user-friendly man-portable LIBS system to characterize samples in real to near-real time (typical analysis time are on the order of minutes) across a wide range of elements in the periodic table from hydrogen up to heavy elements like plutonium and uranium, (2) a LIBS system that can be deployed in harsh environments such as hot cells and glove boxes providing relative compositional analysis of process streams for example ratios like Cm/Up and Cm/U, (3) an inspector field deployable system that can be used to analyze the elemental composition of microscopic quantities of samples containing plutonium and uranium, and (4) a high resolution LIBS system that can be used to determine the isotopic composition of samples containing for example uranium, plutonium... etc. In this paper, we will describe our current development and performance testing results for LIBS instrumentation both in a fixed lab and measurements in field deployable configurations.

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

2010-01-01T23:59:59.000Z

20

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

SciTech Connect

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.

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

2010-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Effect of Atmosphere on Collinear Double-Pulse Laser-Induced Breakdown Spectroscopy  

Science Conference Proceedings (OSTI)

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. In addition to DP-LIBS, atmospheric conditions can also increase spectra intensity. For example, 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 {micro}s 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{sup -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. 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{sup -5} Torr.

Andrew J. Effenberger, Jr; Jill R. Scott

2011-07-01T23:59:59.000Z

22

Laser Induced Spectroscopy  

INL’s Laser Induced Spectroscopy technology detects and measures the composition of a material or the molecules in the material. It traces the ...

23

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

E-Print Network (OSTI)

nuclear power station steam generator tubes by laser-inducednuclear power station steam generator tubes by laser-induced

Effenberger, Andrew Jay

2009-01-01T23:59:59.000Z

24

Laser-induced Breakdown Spectroscopy used to Detect Endophyte-mediated Accumulation of Metals by Tall Fescue  

Science Conference Proceedings (OSTI)

Laser-induced breakdown spectroscopy was used to determine the impact of endophyte (Neotyphodium sp.) infection on elemental composition of tall fescue (Festuca arundinacea). Leaf material from endophyte-infected (E+) and endophyte-free (E-) tall fescue populations in established plots was examined. Leaf-tissue digestates were also tested for metals, by ICP-MS. Seven of eleven metals (Ca, Mg, Fe, Mn, Cu, Ni and Zn) were measured by both techniques at concentrations great enough to reliably compare. Mg, Zn, and Cd, a toxic metal that can be present in forage, were readily detected by LIBS, even though Cd concentrations in the plants were below levels typically achieved using ICP-MS detection. Implications of these results for research on forage analysis and phytoremediation are discussed.

Martin, Madhavi Z [ORNL; Stewart, Arthur J [ORNL; Gwinn, Dr. Kimberley [University of Tennessee, Knoxville (UTK); Waller, John C [ORNL

2010-01-01T23:59:59.000Z

25

Comparison of a transmission grating spectrometer to a reflective grating spectrometer for standoff laser-induced breakdown spectroscopy measurements  

Science Conference Proceedings (OSTI)

We evaluate a new transmission grating spectrometer for standoff laser-induced breakdown spectroscopy (LIBS) measurements. LIBS spectra collected from standoff distances are often weak, with smaller peaks blending into the background and noise. Scattered light inside the spectrometer can also contribute to poor signal-to-background and signal-to-noise ratios for smaller emission peaks. Further, collecting standoff spectra can be difficult because most spectrometers are designed for laboratory environments and not for measurements in the field. To address these issues, a custom-designed small, lightweight transmission grating spectrometer with no moving parts was built that is well suited for standoff LIBS field measurements. The performance of the spectrometer was quantified through 10 m standoff LIBS measurements collected from aluminum alloy samples and measurements from spectra of a Hg-Ar lamp. The measurements were compared to those collected using a Czerny-Turner reflective grating spectrometer that covered a similar spectral range and used the same ICCD camera. Measurements using the transmission grating spectrometer had a 363% improved signal-to-noise ratio when measured using the 669 nm aluminum emission peak.

Weisberg, Arel; Craparo, Joseph; De Saro, Robert; Pawluczyk, Romuald

2010-05-01T23:59:59.000Z

26

,* Copper transport and accumulation in spruce stems (picea abies(L.) Karsten) revelaed by laser-induced breakdown spectroscopy  

SciTech Connect

Laser-Induced Breakdown Spectroscopy (LIBS) in double pulse configuration (DP LIBS) was used for scanning elemental spatial distribution in annual terminal stems of spruce (Picea abies (L.) Karsten). Cross sections of stems cultivated in Cu2+ solution of different concentrations were prepared and analyzed by DP LIBS. Raster scanning with 150 m spatial resolution was set and 2D (2-dimentional) maps of Cu and Ca distribution were created on the basis of the data obtained. Stem parts originating in the vicinity of the implementation of the cross sections were mineralized and subsequently Cu and Ca contents were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The results provide quantitative information about overall concentration of the elements in places, where LIBS measurements were performed. The fluorescence pictures were created to compare LIBS distribution maps and the fluorescence intensity (or the increase in autofluorescence) was used for the comparison of ICP-MS quantitative results. Results from these three methods can be utilized for quantitative measurements of copper ions transport in different plant compartments in dependence on the concentration of cultivation medium and/or the time of cultivation.

Krajcarova, Dr. Lucie [Czech Technical University; Novotny, Dr. Karel [Mendel University of Brno; Babula, Dr. Petr [Czech Technical University; Pravaznik, Dr Ivo [Czech Technical University; Kucerova, Dr. Petra [Czech Technical University; Vojtech, Dr. Adam [Czech Technical University; Martin, Madhavi Z [ORNL; Kizek, Dr. Rene [Czech Technical University; Kaiser, Jozef [ORNL

2013-01-01T23:59:59.000Z

27

Double-pulse and single-pulse laser-induced breakdown spectroscopy for distinguishing between gaseous and particulate phase analytes  

SciTech Connect

We explore the use of a combination of double-pulse and single-pulse laser-induced breakdown spectroscopy (LIBS) methodologies as a means of differentiating between solid-phase and gaseous-phase analytes (namely, carbon) in an aerosol stream. A range of spectral data was recorded for double-pulse and single-pulse configurations, including both ns and fs prepulse widths, while varying the gas-phase mass percentage of the carbon from about 10% to 90% for various fixed carbon concentrations. The carbon emission response, as measured by the peak-to-continuum ratio, was greater for the double-pulse configuration as compared with the single-pulse response and was also enhanced as the percentage of solid-phase carbon was increased. Using a combination of the double-pulse and single-pulse emission signals, a monotonically increasing response function was found to correlate with the percentage of gas-phase analyte. However, individual data points at the measured gas-phase percentages reveal considerable scatter from the predicted trend. Furthermore, the double-pulse to single-pulse ratio was only pronounced with the ns-ns configuration as compared with the fs-ns scheme. Overall, the LIBS methodology has been demonstrated as a potential means to discriminate between gas-phase and particulate-phase fractions of the same elemental species in an aerosol, although future optimization of the temporal parameters should be explored to improve the precision and accuracy of this approach.

Asgill, Michael E.; Brown, Michael S.; Frische, Kyle; Roquemore, William M.; Hahn, David W.

2010-05-01T23:59:59.000Z

28

Femtosecond laser induced breakdown for combustion diagnostics  

Science Conference Proceedings (OSTI)

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.

Kotzagianni, M. [Department of Physics, University of Patras, 26504 Patras (Greece); Institute of Chemical Engineering and High Temperature Chemical Processes (ICE-HT), Foundation for Research and Technology-Hellas (FORTH), 26504 Patras (Greece); Couris, S. [Department of Physics, University of Patras, 26504 Patras (Greece); Institute of Chemical Engineering and High Temperature Chemical Processes (ICE-HT), Foundation for Research and Technology-Hellas (FORTH), 26504 Patras (Greece); Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), Universite de Bourgogne, 21078 Dijon Cedex (France)

2012-06-25T23:59:59.000Z

29

Detection of chlorine with concentration of 0.18 kg/m{sup 3} in concrete by laser-induced breakdown spectroscopy  

Science Conference Proceedings (OSTI)

The chlorine concentration in concrete samples was measured by laser-induced breakdown spectroscopy (LIBS). One or two pulsed second harmonic Nd:YAG lasers ({lambda}=532 nm) were used for the generation of laser-induced breakdown, and an intensified CCD camera, spectrometer, and optical bundle fiber were used for spectral measurement. To maximize the spectral intensity of the chlorine fluorescence line at a wavelength of 837.59 nm, the time delay between laser irradiation and spectral measurement, the time delay between the two laser pulses in double-pulse measurement, and the gate width of the spectral measurement were optimized. The linear relationship between the spectral intensity of the chlorine fluorescence line and the chlorine concentration was verified for pressed samples with chlorine concentrations from 0.18 to 5.4 kg/m{sup 3}. The signal-to-noise ratio was higher than 2 for the sample with a chlorine concentration of 0.18 kg/m{sup 3} (0.008 wt. %). Thus, a chlorine concentration of 0.6 kg/m{sup 3}, at which the reinforcing bars in concrete structures start to corrode, can be detected. These results show that LIBS is effective for the quantitative measurement of chlorine concentration in concrete with high sensitivity.

Sugiyama, K.; Fujii, T.; Matsumura, T.; Shiogama, Y.; Yamaguchi, M.; Nemoto, K.

2010-05-01T23:59:59.000Z

30

Synergetic effects of double laser pulses for the formation of mild plasma in water: Toward non-gated underwater laser-induced breakdown spectroscopy  

Science Conference Proceedings (OSTI)

We experimentally study the dynamics of the plasma induced by the double-laser-pulse irradiation of solid target in water, and find that an appropriate choice of the pulse energies and pulse interval results in the production of an unprecedentedly mild (low-density) plasma, the emission spectra of which are very narrow even without the time-gated detection. The optimum pulse interval and pulse energies are 15-30 {mu}s and about {approx}1 mJ, respectively, where the latter values are much smaller than those typically employed for this kind of study. In order to clarify the mechanism for the formation of mild plasma we examine the role of the first and second laser pulses, and find that the first pulse produces the cavitation bubble without emission (and hence plasma), and the second pulse induces the mild plasma in the cavitation bubble. These findings may present a new phase of underwater laser-induced breakdown spectroscopy.

Sakka, Tetsuo [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan); Institute of Sustainability Science, Kyoto University, Uji, Kyoto 611-0011 (Japan); Tamura, Ayaka; Nakajima, Takashi; Fukami, Kazuhiro; Ogata, Yukio H. [Institute of Advanced Energy, Kyoto University, Uji, Kyoto 611-0011 (Japan)

2012-05-07T23:59:59.000Z

31

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

SciTech Connect

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.

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

2009-08-15T23:59:59.000Z

32

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

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

Lee Spangler; Ross Bricklemyer; David Brown

2012-03-15T23:59:59.000Z

33

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)  

Science Conference Proceedings (OSTI)

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

Lee Spangler; Ross Bricklemyer; David Brown

2012-03-15T23:59:59.000Z

34

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

DOE Patents (OSTI)

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.

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)

2008-05-06T23:59:59.000Z

35

Aerosol measurements with laser-induced breakdown spectroscopy  

E-Print Network (OSTI)

anthropogenic sulfate aerosols. Tellus, Ser. A, vol. 43, p.Twomey, Atmospheric Aerosols. New York : Elsevier ScientificCo. , 45. B.A. Albrecht, Aerosols, cloud microphysics, and

Lithgow, Gregg Arthur

2007-01-01T23:59:59.000Z

36

Laser Induced Breakdown Spectroscopy and Applications Toward Thin Film Analysis  

E-Print Network (OSTI)

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

Owens, Travis Nathan

2011-01-01T23:59:59.000Z

37

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

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.

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

2010-12-23T23:59:59.000Z

38

Measurement of Fuel Dilution of Oil in a Diesel Engine using Laser-Induced Fluorescence Spectroscopy  

DOE Green Energy (OSTI)

A technique for measuring the fuel dilution of oil in a diesel engine is presented. Fuel dilution can occur when advanced in-cylinder fuel injection techniques are employed for the purpose of producing rich exhaust for lean NOx trap catalyst regeneration. Laser-induced fluorescence (LIF) spectroscopy is used to monitor the oil in a Mercedes 1.7-liter engine operated on a dynamometer platform. A fluorescent dye suitable for use in diesel fuel and oil systems is added to the engine fuel. The LIF spectra are monitored to detect the growth of the dye signal relative to the background fluorescence of the oil; fuel mass concentration is quantified based on a known sample set. The technique was implemented with fiber optic probes which can be inserted at various points in the oil system of the engine. A low cost 532-nm laser diode was used for excitation of the fluorescence. Measurements of fuel dilution of oil are presented for various in-cylinder injection strategies for rich operation of the diesel engine. Rates of fuel dilution increase for all strategies relative to normal lean operation, and higher fuel dilution rates are observed when extra fuel injection occurs later in the combustion cycle when fuel penetration into the cylinder wall oil film is more likely.

Parks, II, James E [ORNL; Partridge Jr, William P [ORNL

2007-01-01T23:59:59.000Z

39

Comparative study of femtosecond and nanosecond laser-induced breakdown spectroscopy of depleted uranium  

SciTech Connect

We present spectra of depleted uranium metal from laser plasmas generated by nanosecond Nd:YAG (1064 nm) and femtosecond Ti:sapphire (800 nm) laser pulses. The latter pulses produce short-lived and relatively cool plasmas in comparison to the longer pulses, and the spectra of neutral uranium atoms appear immediately after excitation. Evidence for nonequilibrium excitation with femtosecond pulses is found in the dependence of spectral line intensities on the pulse chirp.

Emmert, Luke A.; Chinni, Rosemarie C.; Cremers, David A.; Jones, C. Randy; Rudolph, Wolfgang

2011-01-20T23:59:59.000Z

40

Applications of High Resolution Laser Induced Breakdown Spectroscopy for Environmental and Biological Samples  

SciTech Connect

This chapter details the application of LIBS in a number of environmental areas of research such as carbon sequestration and climate change. LIBS has also been shown to be useful in other high resolution environmental applications for example, elemental mapping and detection of metals in plant materials. LIBS has also been used in phytoremediation applications. Other biological research involves a detailed understanding of wood chemistry response to precipitation variations and also to forest fires. A cross-section of Mountain pine (pinceae Pinus pungen Lamb.) was scanned using a translational stage to determine the differences in the chemical features both before and after a fire event. Consequently, by monitoring the elemental composition pattern of a tree and by looking for abrupt changes, one can reconstruct the disturbance history of a tree and a forest. Lastly we have shown that multivariate analysis of the LIBS data is necessary to standardize the analysis and correlate to other standard laboratory techniques. LIBS along with multivariate statistical analysis makes it a very powerful technology that can be transferred from laboratory to field applications with ease.

Martin, Madhavi Z [ORNL; Labbe, Nicole [ORNL; Wagner, Rebekah J. [Pennsylvania State University, University Park, PA

2013-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
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41

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

E-Print Network (OSTI)

from laser ablation of brass. Analytical Chemistry, vol. 77,femtosecond laser ablation of brass: particulate and ICPMSand nanosecond laser ablation of brass. Journal Analytical

Effenberger, Andrew Jay

2009-01-01T23:59:59.000Z

42

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

E-Print Network (OSTI)

Common and Trace Elements in Molten Salts using LIBS….81 4.1would be to repeat the molten salt experiment discussed inspectra comparing pure molten salt with Cr doped…………….. . 95

Effenberger, Andrew Jay

2009-01-01T23:59:59.000Z

43

Breakdown  

Science Conference Proceedings (OSTI)

...M. Ieda, Dielectric Breakdown Process of Polymers, IEEE Trans. Electr. Insul., Vol EI-15 (No. 3), 1980, p 206...

44

Laser-Induced Underwater Plasma And Its Spectroscopic Applications  

SciTech Connect

Applications of Laser Induced Breakdown Spectroscopy (LIBS) for analysis of immersed solid and soft materials, and for liquid impurities are described. A method for improving the LIBS signal underwater and for obtaining quantitative analyses in presence of strong shot-to-shot variations of the plasma properties is proposed. Dynamic of the gas bubble formed by the laser pulse is also discussed, together with its importance in Double-Pulse (DP) laser excitation. Results of the studies relative to an application of multi-pulse sequence and its effects on the plasma and gas bubble formation are also presented.

Lazic, Violeta [ENEA, FIS-LAS, Via. E. Fermi 45, 00044 Frascati (Italy)

2008-09-23T23:59:59.000Z

45

Program on Technology Innovation: Feasibility of Laser-Induced Breakdown Spectroscopy for Fuel Analysis in Gasification Applications  

Science Conference Proceedings (OSTI)

Information on the composition of minerals in fuels and the slagging characteristics of the fuels are important for the efficient operation of gasifiers for power generation. Standard fuel fusibility and viscosity analysis have practical limitations that prevent their being used reliably to control real gasification processes. Recent developments in advanced laser-based methods have confirmed some maturity in technologies that could be used to determine coal elemental composition and properties. A study ...

2011-03-07T23:59:59.000Z

46

Plume splitting and rebounding in a high-intensity CO{sub 2} laser induced air plasma  

Science Conference Proceedings (OSTI)

The dynamics of plasma plume formed by high-intensity CO{sub 2} laser induced breakdown of air at atmospheric pressure is investigated. The laser wavelength is 10.6 {mu}m. Measurements were made using 3 ns gated fast photography as well as space and time resolved optical emission spectroscopy. The behavior of the plasma plume was studied with a laser energy of 3 J and 10 J. The results show that the evolution of the plasma plume is very complicated. The splitting and rebounding of the plasma plume is observed to occur early in the plumes history.

Chen Anmin; Jiang Yuanfei; Liu Hang; Jin Mingxing; Ding Dajun [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China)

2012-07-15T23:59:59.000Z

47

Early stage expansion and time-resolved spectral emission of laser-induced  

NLE Websites -- All DOE Office Websites (Extended Search)

Early stage expansion and time-resolved spectral emission of laser-induced Early stage expansion and time-resolved spectral emission of laser-induced plasma from polymer Title Early stage expansion and time-resolved spectral emission of laser-induced plasma from polymer Publication Type Journal Article Year of Publication 2009 Authors Boueri, Myriam, Matthieu Baudelet, Jin Yu, Xianglei Mao, Samuel S. Mao, and Richard E. Russo Journal Applied Surface Science Volume 255 Issue 24 Pagination 9566-9571 Date Published 09/2009 Keywords Early stage plasma expansion, Laser ablation of polymer, Plasma spectral emission Abstract In the nanosecond laser ablation regime, absorption of laser energy by the plasma during its early stage expansion critically influences the properties of the plasma and thus its interaction with ambient air. These influences can significantly alter spectral emission of the plasma. For organic samples especially, recombination of the plasma with the ambient air leads to interfering emissions with respect to emissions due to native species evaporated from the sample. Distinguishing interfering emissions due to ambient air represents a critical issue for the application of laser-induced breakdown spectroscopy (LIBS) to the analysis of organic materials. In this paper, we report observations of early stage expansion and interaction with ambient air of the plasma induced on a typical organic sample (nylon) using timeresolved shadowgraph. We compare, in the nanosecond ablation regime, plasmas induced by infrared (IR) laser pulses (1064 nanometers) and ultraviolet (UV) laser pulses (266 nanometers). Nanosecond ablation is compared with femtosecond ablation where the post-ablation interaction is absent. Subsequent to the early stage expansion, we observe for each studied ablation regime, spectral emission from CN, a typical radical for organic and biological samples. Time-resolved LIBS allows identifying emissions from native molecular species and those due to recombination with ambient air through their different time evolution behaviors.

48

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

E-Print Network (OSTI)

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 ...

Michel, Anna Pauline Miranda, 1976-

2007-01-01T23:59:59.000Z

49

The flip-over effect in self-similar laser-induced plasma expansion  

Science Conference Proceedings (OSTI)

We present a rigorous study of a dynamical model for a nonsymmetric expansion of laser-induced plasma plumes into the vacuum. The model is used in the laser film deposition technique and for remote chemical analysis in the so-called laser-induced breakdown spectroscopy. It defines a particular class of solutions of the hydrodynamics equations when the (plasma) mass density, pressure, and temperature as functions of position have level surfaces that are ellipsoids. The time evolution of ellipsoid semiaxes is determined by the dynamical model. In this model we investigate the flip-over effect: A pancakelike shape of the plasma plume turns into a cigarlike shape and vice versa in due course of its expansion. The effect has been observed in experiments as well as in numerical simulations. In many practical cases, axially symmetric plasma plumes with the adiabatic constant of (5/3) (ideal gas) are used. For this case we prove that the flip-over effect occurs exactly once in the above dynamical model. This rigorous result agrees with the earlier experimental and numerical evidence and, hence, validates a wide applicability of the model.

Baxter, Nathan P.; Shabanov, Sergei V. [Department of Mathematics, University of Florida, Gainesville, Florida 32611 (United States)

2008-09-15T23:59:59.000Z

50

VUV absorption spectroscopy measurements of the role of fast neutral atoms in high-power gap breakdown  

DOE Green Energy (OSTI)

The maximum power achieved in a wide variety of high-power devices, including electron and ion diodes, z pinches, and microwave generators, is presently limited by anode-cathode gap breakdown. A frequently-discussed hypothesis for this effect is ionization of fast neutral atoms injected throughout the anode-cathode gap during the power pulse. The authors describe a newly-developed diagnostic tool that provides the first direct test of this hypothesis. Time-resolved vacuum-ultraviolet absorption spectroscopy is used to directly probe fast neutral atoms with 1 mm spatial resolution in the 10 mm anode-cathode gap of the SABRE 5 MV, 1 TW applied-B ion diode. Absorption spectra collected during Ar RF glow discharges and with CO{sub 2} gas fills confirm the reliability of the diagnostic technique. Throughout the 50--100 ns ion diode pulses no measurable neutral absorption is seen, setting upper limits of 0.12--1.5 x 10{sup 14} cm{sup {minus}3} for ground state fast neutral atom densities of H, C, N, O, F. The absence of molecular absorption bands also sets upper limits of 0.16--1.2 x 10{sup 15} cm{sup {minus}3} for common simple molecules. These limits are low enough to rule out ionization throughout the gap as a breakdown mechanism. This technique can now be applied to quantify the role of neutral atoms in other high-power devices.

FILUK,A.B.; BAILEY,JAMES E.; CUNEO,MICHAEL E.; LAKE,PATRICK WAYNE; NASH,THOMAS J.; NOACK,DONALD D.; MARON,Y.

2000-03-20T23:59:59.000Z

51

In Situ Measurement of Tropospheric OH Radicals by Laser-Induced Fluorescence—A Description of the KFA Instrument  

Science Conference Proceedings (OSTI)

An instrument for the measurement of tropospheric OH radical concentrations by laser-induced fluorescence spectroscopy has been developed. Ambient air is expanded through a nozzle into a low-pressure fluorescence cell and is irradiated by a ...

F. Holland; M. Hessling; A. Hofzumahaus

1995-10-01T23:59:59.000Z

52

Direct evidence of mismatching effect on H emission in laser-induced atmospheric helium gas plasma  

Science Conference Proceedings (OSTI)

A time-resolved orthogonal double pulse laser-induced breakdown spectroscopy (LIBS) with helium surrounding gas is developed for the explicit demonstration of time mismatch between the passage of fast moving impurity hydrogen atoms and the formation of thermal shock wave plasma generated by the relatively slow moving major host atoms of much greater masses ablated from the same sample. Although this so-called 'mismatching effect' has been consistently shown to be responsible for the gas pressure induced intensity diminution of hydrogen emission in a number of LIBS measurements using different ambient gases, its explicit demonstration has yet to be reported. The previously reported helium assisted excitation process has made possible the use of surrounding helium gas in our experimental set-up for showing that the ablated hydrogen atoms indeed move faster than the simultaneously ablated much heavier major host atoms as signaled by the earlier H emission in the helium plasma generated by a separate laser prior to the laser ablation. This conclusion is further substantiated by the observed dominant distribution of H atoms in the forward cone-shaped target plasma.

Zener Sukra Lie; Koo Hendrik Kurniawan [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); May On Tjia [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia); Rinda, Hedwig [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Suliyanti, Maria Margaretha [Research Center for Physics, Indonesia Institute of Sciences, Kawasan PUSPIPTEK, Serpong, Tangerang Selatan 15314, Banten (Indonesia); Syahrun Nur Abdulmadjid; Nasrullah Idris [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Alion Mangasi Marpaung [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, Rawamangun, Jakarta 12440 (Indonesia); Marincan Pardede [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Jobiliong, Eric [Department of Industrial Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Muliadi Ramli [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Heri Suyanto [Department of Physics, Faculty of Mathematics and Natural Sciences, Udayana University, Kampus Bukit Jimbaran, Denpasar 80361, Bali (Indonesia); Fukumoto, Kenichi; Kagawa, Kiichiro [Research Institute of Nuclear Engineering, University of Fukui, Fukui 910-8507 (Japan)

2013-02-07T23:59:59.000Z

53

Laser induced fluorescence of trapped molecular ions  

SciTech Connect

Laser induced fluoresence (LIF) spectra (laser excitation spectra) are conceptually among the most simple spectra to obtain. One need only confine a gaseous sample in a suitable container, direct a laser along one axis of the container, and monitor the sample's fluorescence at a right angle to the laser beam. As the laser wavelength is changed, the changes in fluorescence intensity map the absorption spectrum of the sample. (More precisely, only absorption to states which have a significant radiative decay component are monitored.) For ion spectroscopy, one could benefit in many ways by such an experiment. Most optical ion spectra have been observed by emission techniques, and, aside from the problems of spectral analysis, discharge emission methods often produce the spectra of many species, some of which may be unknown or uncertain. Implicit in the description of LIF given above is certainty as to the chemical identity of the carrier of the spectrum. This article describes a method by which the simplifying aspects of LIF can be extended to molecular ions (albeit with a considerable increase in experimental complexity over that necessary for stable neutral molecules).

Winn, J.S.

1980-10-01T23:59:59.000Z

54

The interaction of 193-nm excimer laser radiation with single-crystal zinc oxide: The generation of atomic Zn line emission at laser fluences below breakdown  

SciTech Connect

The production of gas phase atomic and ionic line spectra accompanying the high laser fluence irradiation of solid surfaces is well known and is most often due to the production and interaction of high densities of atoms, ions, and electrons generated from laser-induced breakdown. The resulting plasma expands and moves rapidly away from the irradiated spot and is accompanied by intense emission of light. This type of plume is well studied and is frequently exploited in the technique of chemical analysis known as laser induced breakdown spectroscopy. Here, we describe a similar but weaker emission of light generated in vacuum by the laser irradiation of single crystal ZnO at fluences well below breakdown; this emission consists entirely of optical line emission from excited atomic Zn. We compare the properties of the resulting laser-generated gas-phase light emission (above and below breakdown) and describe a mechanism for the production of the low-fluence optical emission resulting from a fortuitous choice of material and laser wavelength.

Kahn, E. H. [Washington State University, Pullman; Langford, S. C. [Washington State University, Pullman; Dickinson, J. T. [Washington State University, Pullman; Boatner, Lynn A [ORNL

2013-01-01T23:59:59.000Z

55

Dielectric Breakdown  

Science Conference Proceedings (OSTI)

... Contents. What is a Dielectric Breakdown? High-voltage transformers contain oil as their insulating dielectric. ... Figure 1: 4th-power-law example. ...

2011-01-12T23:59:59.000Z

56

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

SciTech Connect

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.

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)

2012-03-01T23:59:59.000Z

57

Carbon Isotope Separation and Molecular Formation in Laser-Induced...  

NLE Websites -- All DOE Office Websites (Extended Search)

Carbon Isotope Separation and Molecular Formation in Laser-Induced Plasmas by Laser Ablation Molecular Isotopic Spectrometry Title Carbon Isotope Separation and Molecular Formation...

58

Laser-Induced Damage of Calcium Fluoride  

Science Conference Proceedings (OSTI)

Radiation damage of materials has long been of fundamental interest, especially since the growth of laser technology. One such source of damage comes from UV laser light. Laser systems continue to move into shorter wavelength ranges, but unfortunately are limited by the damage threshold of their optical components. For example, semiconductor lithography is making its way into the 157nm range and requires a material that can not only transmit this light (air cannot), but also withstand the highly energetic photons present at this shorter wavelength. CaF2, an alkaline earth halide, is the chosen material for vacuum UV 157 nm excimer radiation. It can transmit light down to 120 nm and is relatively inexpensive. Although it is readily available through natural and synthetic sources, it is often times difficult to find in high purity. Impurities in the crystal can result in occupied states in the band gap that induce photon absorption [2] and ultimately lead to the degradation of the material. In order to predict how well CaF2 will perform under irradiation of short wavelength laser light, one must understand the mechanisms for laser-induced damage. Laser damage is often a two-step process: initial photons create new defects in the lattice and subsequent photons excite these defects. When laser light is incident on a solid surface there is an initial production of electron-hole (e-h) pairs, a heating of free electrons and a generation of local heating around optically absorbing centers [3]. Once this initial excitation converts to the driving energy for nuclear motion, the result is an ejection of atoms, ions and molecules from the surface, known as desorption or ablation [3]. Secondary processes further driving desorption are photoabsorption, successive excitations of self-trapped excitons (STE's) and defects, and ionization of neutrals by incident laser light [3]. The combination of laser-induced desorption and the alterations to the electronic and geometrical structure of the lattice result in defect formation. In the material CaF2 some of these defects take the form of F-centers, an electron trapped at a halogen vacancy [4], and H-centers, a F2- molecular ion at a single lattice site [5]. While the F-centers are stable, the H-centers are transient but can form into aggregates that are stable. There are many different configurations the defects can take based on the relative position of F and H centers in the lattice and this is extensively discussed in literature [1,4,5]. Once these defects have formed they cause further absorption of light, which ultimately induces particle emission and the production of even more defects. Various forms of laser-induced damage of CaF2 have been studied. For example, the mechanism for photon-stimulated desorption (PSD) of F+ from CaF2 (111) is discussed in ref. 6 and the energy threshold, distribution and kinetics governing electron-stimulated desorption (ESD) is investigated in ref. 7. The desorption of neutral Ca and F atoms has also been explored [1]. In this paper I focus on the emission of ions and neutrals from CaF2 under the irradiation of pulsed laser light at 266 nm, in addition to a brief study of its purity and transmittance.

Espana, Aubrey L.; Joly, Alan G.; Hess, Wayne P.; Dickinson, J T.

2004-12-01T23:59:59.000Z

59

" A Heterodyne Laser-induced Fluorescence Technique to Determine  

NLE Websites -- All DOE Office Websites (Extended Search)

A Heterodyne Laser-induced Fluorescence Technique to Determine A Heterodyne Laser-induced Fluorescence Technique to Determine Simultaneously the Bulk and Time Varying Molecule Velocity Distribution." Inventors Ahmed Diallo, Stephane Mazouffre.The method's primary goal is to determine simultaneously the bulk a The method's primary goal is to determine simultaneously the bulk and the time verying part of the molecule velocity distribution using a heterodyne laser induced fluorescence technique. Used in biology, chemistry and plasma physics laser-induced fluorescence is a well known technique to resolve the bulk velocity distribution of probed molecules and atoms in a medium. The novel approach is aimed at determining not only the bulk distribution, but also the time-varying velocity distribution. The two parts of the velocity distribution are key in the characterization of a

60

Publications  

NLE Websites -- All DOE Office Websites (Extended Search)

Vasileia, Jaroslaw Syzdek, Xianglei Mao, Richard E. Russo, and Robert Kostecki. "Ultrafast laser induced breakdown spectroscopy of electrodeelectrolyte interfaces." Applied...

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Laser-Induced Damage of Calcium Fluoride  

Science Conference Proceedings (OSTI)

As advances continue to be made in laser technology there is an increasing demand for materials that have high thresholds for laser-induced damage. Laser damage occurs when light is absorbed, creating defects in the crystal lattice. These defects can lead to the emission of atoms, ions and molecules from the sample. One specific field where laser damage is of serious concern is semiconductor lithography, which is beginning to use light at a wavelength of 157 nm. CaF2 is a candidate material for use in this new generation of lithography. In order to prevent unnecessary damage of optical components, it is necessary to understand the mechanisms for laser damage and the factors that serve to enhance it. In this research, we study various aspects of laser interactions with CaF2, including impurity absorbance and various forms of damage caused by incident laser light. Ultraviolet (UV) laser light at 266 nm with both femtosecond (fs) and nanosecond (ns) pulse widths is used to induce ion and neutral particle emission from cleaved samples of CaF2. The resulting mass spectra show significant differences suggesting that different mechanisms for desorption occur following excitation using the different pulse durations. Following irradiation by ns pulses at 266 nm, multiple single-photon absorption from defect states is likely responsible for ion emission whereas the fs case is driven by a multi-photon absorption process. This idea is further supported by the measurements made of the transmission and reflection of fs laser pulses at 266 nm, the results of which reveal a non-linear absorption process in effect at high incident intensities. In addition, the kinetic energy profiles of desorbed Ca and K contaminant atoms are different indicating that a different mechanism is responsible for their emission as well. Overall, these results show that purity plays a key role in the desorption of atoms from CaF2 when using ns pulses. On the other hand, once the irradiance reaches high levels, like that of the fs case, significant desorption is possible due to multi-photon absorption by the intrinsic material.

Espana, A.; Joly, A.G.; Hess, W.P.; Dickinson, J.T.

2004-01-01T23:59:59.000Z

62

High resolution analysis of soil elements with laser-induced breakdown  

SciTech Connect

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.

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

2010-04-06T23:59:59.000Z

63

Method of molecular specie alteration by nonresonant laser induced dielectric breakdown  

DOE Patents (OSTI)

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.

Ronn, Avigdor M. (Great Neck, NY)

1980-01-01T23:59:59.000Z

64

Laser-induced differential normalized fluorescence method for cancer diagnosis  

SciTech Connect

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.

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

1996-01-01T23:59:59.000Z

65

High frequency breakdown voltage  

SciTech Connect

This report contains information about the effect of frequency on the breakdown voltage of an air gap at standard pressure and temperature, 76 mm Hg and O{degrees}C, respectively. The frequencies of interest are 47 MHz and 60 MHz. Additionally, the breakdown in vacuum is briefly considered. The breakdown mechanism is explained on the basis of collision and ionization. The presence of the positive ions produced by ionization enhances the field in the gap, and thus determines the breakdown. When a low-frequency voltage is applied across the gap, the breakdown mechanism is the same as that caused by the DC or static voltage. However, when the frequency exceeds the first critical value f{sub c}, the positive ions are trapped in the gap, increasing the field considerably. This makes the breakdown occur earlier; in other words, the breakdown voltage is lowered. As the frequency increases two decades or more, the second critical frequency, f{sub ce}, is reached. This time the electrons start being trapped in the gap. Those electrons that travel multiple times across the gap before reaching the positive electrode result in an enormous number of electrons and positive ions being present in the gap. The result is a further decrease of the breakdown voltage. However, increasing the frequency does not decrease the breakdown voltage correspondingly. In fact, the associated breakdown field intensity is almost constant (about 29 kV/cm).The reason is that the recombination rate increases and counterbalances the production rate, thus reducing the effect of the positive ions` concentration in the gap. The theory of collision and ionization does not apply to the breakdown in vacuum. It seems that the breakdown in vacuum is primarily determined by the irregularities on the surfaces of the electrodes. Therefore, the effect of frequency on the breakdown, if any, is of secondary importance.

Chu, Thanh Duy

1992-03-01T23:59:59.000Z

66

Ultratrace analysis of transuranic actinides by laser-induced fluorescence  

DOE Patents (OSTI)

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.

Miller, Steven M. (Chelmsford, MA)

1988-01-01T23:59:59.000Z

67

Ultrafast electron beam imaging of femtosecond laser-induced plasma  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast electron beam imaging of femtosecond laser-induced plasma Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Title Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Publication Type Journal Article Year of Publication 2010 Authors Li, Junjie, Xuan Wang, Zhaoyang Chen, Richard Clinite, Samuel S. Mao, Pengfei Zhu, Zhengming Sheng, Jie Zhang, and Jianming Cao Journal Journal of Applied Physics Volume 107 Issue 8 Date Published 03/2010 Keywords copper, electron beam applications, high-speed optical techniques, laser ablation, plasma diagnostics, plasma production by laser Abstract Plasma dynamics in the early stage of laser ablation of a copper target are investigated in real time by making ultrafast electron shadow images and electron deflectometry measurements. These complementary techniques provide both a global view and a local perspective of the associated transient electric field and charge expansion dynamics. The results reveal that the charge cloud above the target surface is composed predominantly of thermally ejected electrons and that it is self-expanding, with a fast front-layer speed exceeding 107 m/s. The average electric field strength of the charge cloud induced by a pump fluence of 2.2 J/cm2 is estimated to be ∼ 2.4×105 V/m.

68

Patterning of Bi2O3 films using laser-induced forward and backward transfer techniques  

Science Conference Proceedings (OSTI)

Patterning of Bi"2O"3 films was performed by laser-induced forward transfer (LIFT) and backward transfer (LIBT) techniques using the SHG beam of a Nd:YAG pulsed laser. Patterned parallel tracks of the transferred film were obtained on glass sample plates ... Keywords: AFM, Bi2O3 film, Laser-induced backward transfer, Laser-induced forward transfer, SEM, SHG Nd:YAG laser

H. Sakata; S. Chakraborty; M. Wakaki

2012-08-01T23:59:59.000Z

69

Spectroscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

Spectroscopy Spectroscopy Spectroscopy Print In spectroscopy experiments, a sample is illuminated with light and the various product particles (electrons, ions, or fluorescent photons) are detected and analyzed.The unifying feature is that some "property" of a material is measured as the x-ray (photon) energy is swept though a range of values. At the most basic level, one measures the absorption, transmission, or reflectivity of a sample as a function of photon energy. Probes that use the vacuum ultraviolet (VUV) region of the spectrum (10-100 eV) are very well matched to the elucidation of bonding in solids, surfaces, and molecules; to the investigation of electron-electron correlations in solids, atoms, and ions; and to the study of reaction pathways in chemical dynamics. At the lowest end of this energy range (below 1 eV) we have infrared, far-infrared, and terahertz spectroscopies, which are well matched to vibrational modes and other modes of excitation.

70

Spectroscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

Spectroscopy Print Spectroscopy Print In spectroscopy experiments, a sample is illuminated with light and the various product particles (electrons, ions, or fluorescent photons) are detected and analyzed.The unifying feature is that some "property" of a material is measured as the x-ray (photon) energy is swept though a range of values. At the most basic level, one measures the absorption, transmission, or reflectivity of a sample as a function of photon energy. Probes that use the vacuum ultraviolet (VUV) region of the spectrum (10-100 eV) are very well matched to the elucidation of bonding in solids, surfaces, and molecules; to the investigation of electron-electron correlations in solids, atoms, and ions; and to the study of reaction pathways in chemical dynamics. At the lowest end of this energy range (below 1 eV) we have infrared, far-infrared, and terahertz spectroscopies, which are well matched to vibrational modes and other modes of excitation.

71

Spectroscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

Spectroscopy Print Spectroscopy Print In spectroscopy experiments, a sample is illuminated with light and the various product particles (electrons, ions, or fluorescent photons) are detected and analyzed.The unifying feature is that some "property" of a material is measured as the x-ray (photon) energy is swept though a range of values. At the most basic level, one measures the absorption, transmission, or reflectivity of a sample as a function of photon energy. Probes that use the vacuum ultraviolet (VUV) region of the spectrum (10-100 eV) are very well matched to the elucidation of bonding in solids, surfaces, and molecules; to the investigation of electron-electron correlations in solids, atoms, and ions; and to the study of reaction pathways in chemical dynamics. At the lowest end of this energy range (below 1 eV) we have infrared, far-infrared, and terahertz spectroscopies, which are well matched to vibrational modes and other modes of excitation.

72

Particulate measurement issues in diesel exhausts using laser induced incandescence  

DOE Green Energy (OSTI)

A number of studies in the recent past have identified Laser Induced Incandescence (LII) as a versatile technique for in-flame measurement of soot concentrations. Recently, a number of researchers have focused their attention in adapting this technique to measure particulate in diesel exhausts. However the agreement with established physical sampling techniques, such as the EPA recommended filter paper collection method, was found to be less than ideal. This paper reports the efforts to adapt this technique for diesel exhaust characterization. Many of the factors affecting LII signal were identified through computer modeling. Parameters that could not be determined through such a model were determined experimentally following a parametric study. Subsequently, LII measurements were performed in the exhaust of a modified lab burner, with conditions close to that of diesel engine exhausts. Such measurements show excellent agreement with those performed using the standard filter paper collection technique.

Gupta, S. B.; Poola, R. B.; Sekar, R.

2000-07-03T23:59:59.000Z

73

Fluence thresholds for laser-induced damage of optical components in the injector laser of the SSRL gun test facility  

E-Print Network (OSTI)

Fluence thresholds for laser-induced damage of optical components in the injector laser of the SSRL gun test facility

Bolton, P

2001-01-01T23:59:59.000Z

74

Structure Breakdown Workshop Schedule  

NLE Websites -- All DOE Office Websites (Extended Search)

Breakdown Breakdown Workshop SLAC, Orange Room August 28 - 30 , 2000 Announcement Workshop Poster Workshop Goals: The Goal of the workshop is to review understanding of warm structure breakdown phenomena, to define common terms for comparing tests and to identify avenues for further study. For a partial bibliography, please view the following URL : http://www-project.slac.stanford.edu/lc/wkshp/RFBreakdwn/references/publist.htm Schedule and Presentations: Monday, August 28 8:30 - Operation Experience and Definition of Problem Moderator - G. Loew (initial questions) Opening remarks and introduction (C. Adolphsen) (15min) CERN Structure Operation Results (W. Wuensch) (30 min) NLCTA Structure Operation Results (C. Adolphsen) (30 min) ASTA Structure Operation Results (R. Loewen) (20 min)

75

Quenching-independent measurement of species concentrations in flames by laser-induced fluorescence  

DOE Green Energy (OSTI)

This report describes work accomplished in the last two years on measurement of species concentrations in flames via laser-induced fluorescence. During this period, we have published absolute number densities of atomic hydrogen in subatmospheric, premixed C{sub 2}H{sub 4}/O{sub 2}/Ar flames at equivalence ratios of 1.0 and 1.7 via two-photon excited fluorescence. This work has led to the development of a new single-laser, two-step fluorescence method for the detection of atomic hydrogen in flames. Using photoionization controlled-loss spectroscopy (PICLS), we have verified the T{sup {minus}1/2} dependence of quenching on temperature for atomic hydrogen, in agreement with kinetic theory. Previous work on pyrometry using laser-saturated fluorescence (LSF) and the anomalous fluorescence from pyrene has evolved into publication of a major review paper on temperature measurements by light-scattering methods. Finally, we have demonstrated the feasibility of quantitative LSF measurements of NO concentration by obtaining relative saturation curves and NO fluorescence profiles. 25 refs.

Salmon, J.T.; Carter, C.D.; Laurendeau, N.M.

1990-09-01T23:59:59.000Z

76

Deuterium analysis in zircaloy using ps laser-induced low pressure plasma  

SciTech Connect

An experimental study on picosecond laser induced plasma spectroscopy of a zircaloy sample with low-pressure surrounding helium gas has been carried out to demonstrate its potential applicability to three-dimensional quantitative micro-analysis of deuterium impurities in zircaloy. This was achieved by adopting the optimal experimental condition ascertained in this study, which is specified as 7 mJ laser energy, 1.3 kPa helium pressure, and 50 {mu}s measurement window, and which was found to result in consistent D emission enhancement. Employing these operational parameters, a linear calibration line exhibiting a zero intercept was obtained from zircaloy-4 samples doped with various concentrations of D impurity, regarded as surrogates for H impurity. An additional measurement also yielded a detection limit of about 10 {mu}g/g for D impurity, well below the acceptable threshold of damaging H concentration in zircaloy. Each of these measurements was found to produce a crater size of only 25 {mu}m in diameter, promising its application for performing less-destructive measurements. The result of this study has thus paved the way for conducting a further experiment with hydrogen-doped zircaloy samples and the further technical development of a three-dimensional quantitative micro-analysis of detrimental hydrogen impurity in zircaloy vessels used in nuclear power plants.

Marpaung, Alion Mangasi [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, 10 Rawamangun, Jakarta (Indonesia); Lie, Zener Sukra; Niki, Hideaki [Department of Nuclear Power and Energy Safety Engineering, Graduate School of Engineering, University of Fukui, Fukui 910-8507 (Japan); Kagawa, Kiichiro; Fukumoto, Ken-ichi [Research Institute of Nuclear Engineering, University of Fukui, Fukui 910-8507 (Japan); Ramli, Muliadi [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Abdulmadjid, Syahrun Nur; Idris, Nasrullah [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Hedwig, Rinda [Department of Computer Engineering, Bina Nusantara University, 9 K. H. Syahdan, Jakarta 14810 (Indonesia); Tjia, May On [Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia); Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M. H. Thamrin Boulevard, Lippo Vilage, Tangerang, 15811 (Indonesia); Suliyanti, Maria Margaretha [Research Center for Physics, Indonesian Institute of Sciences, Kawasan PUSPIPTEK, Serpong Tangerang Selatan 15314, Banten (Indonesia); Jobiliong, Eric [Industrial Engineering Department, University of Pelita Harapan, 1100 M. H. Thamrin Boulevard, Lippo Vilage, Tangerang, 15811 (Indonesia); Kurniawan, Koo Hendrik [Research Center of Maju Makmur Mandiri Foundation, 40 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia)

2011-09-15T23:59:59.000Z

77

Costas Grigoropoulos  

NLE Websites -- All DOE Office Websites (Extended Search)

Mao, Erin K. Canfield, Costas P. Grigoropoulos, Xianglei Mao, and Richard E. Russo. "Ultrafast thin-film laser-induced breakdown spectroscopy of doped oxides." Applied Optics 49...

78

Suppressant:Perfluorocarbons (PFCs)  

Science Conference Proceedings (OSTI)

... Acid Gas Production in Inhibited Diffusion Flames.. ... Evaluation of Laser-Induced Breakdown Spectroscopy (LIBS) for ... to an External Energy Source.. ...

2012-03-20T23:59:59.000Z

79

Slide 1  

NLE Websites -- All DOE Office Websites (Extended Search)

Improved Laser Induced Breakdown Spectroscopy (LIBS) Elemental Composition Detection System Dustin L. McIntyre, PhD, PE Mechanical Engineer USDOE - NETL September 17, 2013 the...

80

Independent Oversight Inspection of the Hanford Site Chronic...  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

IH Industrial Hygiene IHT Industrial Hygiene Technician JHA Job Hazard Analysis LIBS Laser Induced Breakdown Spectroscopy Abbreviations Used in This Report iv | Hanford Site...

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Nervous breakdown causes  

NLE Websites -- All DOE Office Websites (Extended Search)

Nervous breakdown causes Nervous breakdown causes Name: Renee Nuckols Status: N/A Age: N/A Location: N/A Country: N/A Date: Around 1993 Question: Physiologically, what causes a mental/nervous breakdown besides normal everyday stress? Is it a process that kills neurons? Also please include some internal and external symptoms that occur prior to, during, and after a nervous breakdown. Replies: "Nervous breakdown" may be a misnomer, though. What "breaks down" is not so much the nerves and neurons, but the adrenal glands. A more accurate term would be the "exhaustion phase of the general adaption syndrome," but obviously that is quite a mouthful. Excessive STRESS is what can cause "nervous breakdowns." Stress includes the obvious things like exam pressures, trouble with parents or teachers, peer pressure, but also includes things like a significant personal achievement, making a major purchase, changes in routines of life (sleeping, eating habits), moving to a different part of town - even the change in seasons and temperatures. It can come from almost anything which causes a disturbance in normal living. Stress triggers a number of physiological changes collectively termed "GENERAL ADAPTATION SYNDROME." There are three phases: 1) alarm, 2) resistance, and 3) exhaustion. These phases are controlled and regulated by the adrenal glands. Your adrenal glands lie just above your kidneys and are composed of inner and outer parts. The inner part is called the adrenal medulla, and it secretes the hormones adrenaline and noradrenaline. These hormones help your body deal with stressful situations. If you were alone and met a gang in some back alley, your adrenal glands would flood your body with the hormones, your blood pressure, heart rate, sweat production would shoot way high! Your body is in a "FIGHT or FLIGHT" mode. (Just thinking about getting in such a situation may have caused some stress!) Well, whenever your body deals with smaller stresses, the same hormones are released. The outer part of the adrenal glands is the adrenal cortex. They also produce hormones, but slightly different ones: glucocorticoids and mineralcorticoids. Glucocorticoids can increase blood sugar levels profoundly, while mineralcorticoids affect mineral excretion. These hormones are largely responsible for helping the body deal with prolonged stress. They help provide extra energy and blood supply. For instance, if you had a whole week of finals, your adrenal cortex would work overtime as you burn the midnight oil studying. These instances are the "resistance" phase of the general adaptation syndrome.

82

Simulation of Laser-Induced Light Emissions from Water and Extraction of Raman Signal  

Science Conference Proceedings (OSTI)

A simulation of the laser-induced Raman and fluorescence spectra produced by laser irradiation of the water column is described as well as a method of extracting the Raman signal from the fluorescence spectra using multiple laser excitation ...

Jeffrey E. James; Chung San Lin; William P. Hooper

1999-03-01T23:59:59.000Z

83

Spectroscopic characterization of laser-induced tin plasma  

E-Print Network (OSTI)

H. R. Griem, Principles of Plasma Spectroscopy ?Cambridge,Beke?, Principles of Laser Plasmas ?Wiley-Interscience, NewIn the early stage of plasma evolution, the electron

Harilal, S S; O'Shay, B; Tillack, M S; Mathew, M V

2005-01-01T23:59:59.000Z

84

Soot temperature measurements and implications for time-resolved laser-induced incandescence (TIRE-LII)  

Science Conference Proceedings (OSTI)

Emission spectroscopy has been used to determine soot particle temperatures in an ethene diffusion flame both under normal combustion conditions and also after irradiation with an intense laser pulse. On the basis of these measurements, a check on the models and an improvement of parameters underlying time-resolved laser-induced incandescence (TIRE-LII) was performed. With this technique a two-dimensionally resolved measurement of soot primary particle sizes is feasible in a combustion process from the ratio of emission signals obtained at two delay times after a laser pulse, as the cooling behavior is characteristic of particle size. For accurate measurements, local gas temperatures must be known, which can be derived from the temperatures of the soot particles themselves. These have been measured by fitting full Planck curves to line-of-sight emission spectra after an inversion algorithm. The temperature and heat of vaporization of soot, which govern the energy and mass loss at high temperatures, were obtained by measurements of maximum particle temperature for various laser irradiances and a fit procedure to the theoretical dependence. Finally, the temperature decay of laser-heated soot was measured with high temporal resolution. Comparisons with model predictions show that soot temperatures are roughly 300 K higher than expected after the onset of vaporization, which indicates deficiencies in the present models of vaporization. It is demonstrated that the TIRE-LII performance is essentially unaffected by these shortcomings if LII signals are detected in a period where conductive heat transfer dominates and an appropriate correction is performed.

Schraml, S.; Dankers, S.; Bader, K.; Will, S.; Leipertz, A.

2000-03-01T23:59:59.000Z

85

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

E-Print Network (OSTI)

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.

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

2013-06-03T23:59:59.000Z

86

The fabrication of small molecule organic light-emitting diode pixels by laser-induced forward transfer  

E-Print Network (OSTI)

The fabrication of small molecule organic light-emitting diode pixels by laser-induced forward online 23 January 2013) Laser-induced forward transfer (LIFT) is a versatile organic light-emitting diode, a modified LIFT process has been used to fabricate small molecule Alq3 organic light-emitting diodes (SMOLEDs

87

Breakdown in the pretext tokamak  

DOE Green Energy (OSTI)

Data are presented on the application of ion cyclotron resonance RF power to preionization in tokamaks. We applied 0.3-3 kW at 12 MHz to hydrogen and obtained a visible discharge, but found no scaling of breakdown voltage with any parameter we were able to vary. A possible explanation for this, which implies that higher RF power would have been much more effective, is discussed. Finally, we present our investigation of the dV/dt dependence of breakdown voltage in PRETEXT, a phenomenon also seen in JFT-2. The breakdown is discussed in terms of the physics of Townsend discharges.

Benesch, J.F.

1981-06-01T23:59:59.000Z

88

Scanning delay generator for measurement of kinetic decays using laser-induced fluorescence techniques  

SciTech Connect

An electronic device is described which generates a delayed pulse, where the delay is increased in a step-like manner. This device finds application in the measurement of kinetic decays, particularly when laser-induced fluorescent (LIF) detection of the decaying species is used. The circuit uses 15 low-power Schottky TTL chips and is contained within a dual width NIM module.

Halpern, J.B.; Towns, T.G.

1982-11-01T23:59:59.000Z

89

X-ray line broadening as a compression diagnostic for laser-induced implosions  

SciTech Connect

It is suggested that the best way to measure maximum compressions in laser-induced implosion experiments may be to measure the line profiles of x-ray lines due to impurities in the compressed material. The experimental difficulties in making such measurements and the theoretical problems of interpreting these measurements are discussed.

Chapline, G.F.; DeWitt, H.E.; Hooper, C.F. Jr.

1974-12-01T23:59:59.000Z

90

DOE Work Breakdown Structure Handbook  

Energy.gov (U.S. Department of Energy (DOE))

This handbook provides suggested guidance and best practices on the development of product-oriented Work Breakdown Structures (WBS) that should be used by all projects within DOE to organize and...

91

AFM CHARACTERIZATION OF RAMAN LASER INDUCED DAMAGE ON CDZNTECRYSTAL SURFACES  

Science Conference Proceedings (OSTI)

High quality CdZnTe (or CZT) crystals have the potential for use in room temperature gamma-ray and X-ray spectrometers. Over the last decade, the methods for growing high quality CZT have improved the quality of the produced crystals however there are material features that can influence the performance of these materials as radiation detectors. The presence of structural heterogeneities within the crystals, such as twinning, pipes, grain boundaries (polycrystallinity), and secondary phases (SPs) can have an impact on the detector performance. There is considerable need for reliable and reproducible characterization methods for the measurement of crystal quality. With improvements in material characterization and synthesis, these crystals may become suitable for widespread use in gamma radiation detection. Characterization techniques currently utilized to test for quality and/or to predict performance of the crystal as a gamma-ray detector include infrared (IR) transmission imaging, synchrotron X-ray topography, photoluminescence spectroscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM) and Raman spectroscopy. In some cases, damage caused by characterization methods can have deleterious effects on the crystal performance. The availability of non-destructive analysis techniques is essential to validate a crystal's quality and its ability to be used for either qualitative or quantitative gamma-ray or X-ray detection. The work presented herein discusses the damage that occurs during characterization of the CZT surface by a laser during Raman spectroscopy, even at minimal laser powers. Previous Raman studies have shown that the localized annealing from tightly focused, low powered lasers results in areas of higher Te concentration on the CZT surface. This type of laser damage on the surface resulted in decreased detector performance which was most likely due to increased leakage current caused by areas of higher Te concentration. In this study, AFM was used to characterize the extent of damage to the CZT crystal surface following exposure to a Raman laser. AFM data reveal localized surface damage and increased conductivity in the areas exposed to the Raman laser beam.

Teague, L.; Duff, M.

2008-10-07T23:59:59.000Z

92

AFM CHARACTERIZATION OF LASER INDUCED DAMAGE ON CDZNTE CRYSTAL SURFACES  

Science Conference Proceedings (OSTI)

Semi-conducting CdZnTe (or CZT) crystals can be used in a variety of detector-type applications. CZT shows great promise for use as a gamma radiation spectrometer. However, its performance is adversely affected by point defects, structural and compositional heterogeneities within the crystals, such as twinning, pipes, grain boundaries (polycrystallinity), secondary phases and in some cases, damage caused by external forces. One example is damage that occurs during characterization of the surface by a laser during Raman spectroscopy. Even minimal laser power can cause Te enriched areas on the surface to appear. The Raman spectra resulting from measurements at moderate intensity laser power show large increases in peak intensity that is attributed to Te. Atomic Force Microscopy (AFM) was used to characterize the extent of damage to the CZT crystal surface following exposure to the Raman laser. AFM data reveal localized surface damage in the areas exposed to the Raman laser beam. The degree of surface damage to the crystal is dependent on the laser power, with the most observable damage occurring at high laser power. Moreover, intensity increases in the Te peaks of the Raman spectra are observed even at low laser power with little to no visible damage observed by AFM. AFM results also suggest that exposure to the same amount of laser power yields different amounts of surface damage depending on whether the exposed surface is the Te terminating face or the Cd terminating face of CZT.

Hawkins, S; Lucile Teague, L; Martine Duff, M; Eliel Villa-Aleman, E

2008-06-10T23:59:59.000Z

93

Prepulse effect on laser-induced water-window radiation from a liquid nitrogen jet  

E-Print Network (OSTI)

is schematically shown in Fig. 1. A high-purity nitrogen gas was cooled and liquefied through the cooling stagesPrepulse effect on laser-induced water-window radiation from a liquid nitrogen jet J. Son,a M. Cho.3­4.4 nm x ray from a liquid nitrogen jet. It is observed that a prepulse of only 2 mJ enhances

Kim, Jae-Hoon

94

Impulse breakdown delay in liquid dielectrics  

E-Print Network (OSTI)

Theoretical images of streamers, revealing the mechanisms behind impulse breakdown in liquid dielectrics, are presented. Streamers lead to electrical breakdown by forming paths, capable of carrying large current amplitudes ...

Jadidian, Jouya

95

RF breakdown effects in microwave power amplifiers  

E-Print Network (OSTI)

Electrical stresses in the transistors of high-efficiency switching power amplifiers can lead to hot-electron-induced "breakdown" in these devices. This thesis explores issues related to breakdown in the Transcom TC2571 ...

Arumilli, Gautham Venkat

2007-01-01T23:59:59.000Z

96

Xenon ion laser-induced fluorescence using a visible tunable diode laser near 680 nm  

SciTech Connect

Laser-induced fluorescence (LIF) measurements have been performed for the first time in a low temperature (T{sub e}{approx_equal}0.6 eV) Xe plasma using a tunable diode laser in the visible range of wavelengths. The transition in Xe II involved the ({sup 3}P{sub 1})5d[3]{sub 7/2} metastable state and the excitation wavelength was found to be 680.570{+-}0.001 nm (air). LIF measurements of I{sub 2} in a room temperature iodine gas cell were used to monitor the wavelength of the laser during the measurements.

Severn, Greg; Lee, Dongsoo; Hershkowitz, Noah [Department of Physics, University of San Diego, San Diego, California 92110 (United States); Department of Engineering Physics, University of Wisconsin at Madison, Madison, Wisconsin 53706 (United States)

2007-11-15T23:59:59.000Z

97

Observation of femtosecond laser-induced nanostructure-covered large scale waves on metals  

SciTech Connect

Following femtosecond (fs) laser pulse irradiation, we produce a type of periodic surface structure with a period tens of times greater than the laser wavelength and densely covered by an iterating pattern that consists of stripes of nanostructures and microscale cellular structures. The morphology of this large scale wave pattern crucially depends on laser fluence and the number of laser pulses, but not on the laser wavelength. Our study suggests that this large scale wave is initiated by fs laser induced surface unevenness followed by periodically distributed nonuniform surface heating from fs pulse irradiation.

Hwang, Taek Yong; Guo Chunlei [Institute of Optics, University of Rochester, Rochester, New York 14627 (United States)

2011-04-15T23:59:59.000Z

98

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

SciTech Connect

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 He{sub 2} 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 {sup 4}He.

McKinsey, D. N.; Lippincott, W.H.; Nikkel, J.A.; Rellergert, W.G. [Department of Physics, Yale University, P.O. Box 208120, New Haven, Connecticut 06520 (United States)

2005-09-09T23:59:59.000Z

99

Laser-induced damage in dielectrics with nanosecond to subpicosecond pulses. I. Experimental. Part 1  

Science Conference Proceedings (OSTI)

The authors report extensive laser-induced damage threshold measurements on pure and multilayer dielectrics at 1053 and 526 mm for pulse durations, {tau}, ranging from 140 fs to 1 ns. Qualitative differences in the morphology of damage and a departure from the diffusion-dominated {tau}{sup 1/2} scaling indicate that damage results from plasma formation and ablation for {tau}{le}10 ps and from conventional melting and boiling for {tau}>50 ps. A theoretical model based on electron production via multiphoton ionization, Joule heating, and collisional (avalanche) ionization is in good agreement with both the pulsewidth and wavelength scaling of experimental results.

Stuart, B.C.; Herman, S.; Perry, M.D.

1994-12-01T23:59:59.000Z

100

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

E-Print Network (OSTI)

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 pulse width in Laser Induced Stress Waves Thermometry (LISWT) for single crystalline silicon processing motivated the work. The model formulation developed is of a hyperbolic type capable of characterizing non-thermal melting and thermo-elastoviscoplastic deformation as functions of laser input parameters and ambient temperature. A plastic constitutive law is followed to describe the complex elasto-viscoplastic responses in silicon undergoing Rapid Thermal Processing (RTP) annealing at elevated temperatures. A system of nine first-order hyperbolic equations applicable to describing 3-D elasto-viscoplastic wave motions in silicon is developed. The group velocities of certain selected frequency components are shown to be viable thermal indicators, thus establishing the feasibility of exploiting nanosecond laser induced propagating stress waves for the high-resolution thermal profiling of silicon wafers. Femtosecond laser induced transport dynamics in silicon is formulated based on the relaxation-time approximation of the Boltzmann equation. Temperature-dependent multi-phonons, free-carrier absorptions, and the recombination and impact ionization processes governing the laser model and carrier numbers are considered using a set of balance equations. The balance equation of lattice energy and equations of motion of both parabolic and hyperbolic types are derived to describe the complex thermo-elastoplastodynamic behaviors of the material in response to ultrafast laser pulsing. The solution strategy implemented includes a multi-time scale axisymmetric model of finite geometry and a staggered-grid finite difference scheme that allows both velocity and stress be simultaneously determined without having to solve for displacements. Transport phenomena initiated by femtosecond pulses including the spatial and temporal evolutions of electron and lattice temperatures, along with electron-hole carrier density, are found to be functions of laser fluence and pulse width. The femtosecond laser heating model that admits hyperbolic energy transport is shown to remedy the dilemma that thermal disturbances propagate with infinite speed. Non-thermal melting fluence is examined favorably against published experimental data. That it is feasible to explore femtosecond laser induced displacement and stress components for 1K resolution thermal profiling is one of the conclusions reached.

Qi, Xuele

2009-12-01T23:59:59.000Z

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101

Laser-induced fusion of human embryonic stem cells with optical tweezers  

SciTech Connect

We report a study on the laser-induced fusion of human embryonic stem cells (hESCs) at the single-cell level. Cells were manipulated by optical tweezers and fused under irradiation with pulsed UV laser at 355 nm. Successful fusion was indicated by green fluorescence protein transfer. The influence of laser pulse energy on the fusion efficiency was investigated. The fused products were viable as gauged by live cell staining. Successful fusion of hESCs with somatic cells was also demonstrated. The reported fusion outcome may facilitate studies of cell differentiation, maturation, and reprogramming.

Chen Shuxun; Wang Xiaolin; Sun Dong [Department of Mechanical and Biomedical Engineering, City University of Hong Kong (Hong Kong); Cheng Jinping; Han Cheng, Shuk [Department of Biology and Chemistry, City University of Hong Kong (Hong Kong); Kong, Chi-Wing [Stem Cell and Regenerative Medicine Consortium, and Departments of Medicine and Physiology, LKS Faculty of Medicine, University of Hong Kong (Hong Kong); Li, Ronald A. [Stem Cell and Regenerative Medicine Consortium, and Departments of Medicine and Physiology, LKS Faculty of Medicine, University of Hong Kong (Hong Kong); Center of Cardiovascular Research, Mount Sinai School of Medicine, New York, New York 10029 (United States)

2013-07-15T23:59:59.000Z

102

Laser-induced implantation of silver particles into poly(vinyl alcohol) films and its application to electronic-circuit fabrication on encapsulated organic electronics  

Science Conference Proceedings (OSTI)

In this study, we propose a new laser-induced implantation based approach for embedding electronic interconnects in this study. Direct implantations of silver particles, vaporized by a pulsed laser from a silver film initially pre-coated on a transparent ... Keywords: Embedded electronic circuits, Encapsulation, Laser-induced implantation, Organic thin-film transistors, Polymeric light-emitting diodes

Kun-Tso Chen; Yu-Hsuan Lin; Jeng-Rong Ho; J.-W. John Cheng; Sung-Ho Liu; Jin-Long Liao; Jing-Yi Yan

2010-04-01T23:59:59.000Z

103

I CALCULATIONS ON ISOTOPE SEPARATION BY LASER INDUCED PHOTODISSOCIATION OF POLYATOMIC MOLECULES  

NLE Websites -- All DOE Office Websites (Extended Search)

; ; . I CALCULATIONS ON ISOTOPE SEPARATION BY LASER INDUCED PHOTODISSOCIATION OF POLYATOMIC MOLECULES F i n a l Report Willis E . Lamb, JY. U n i v e r s i t y of Arizona Tucson, Arizona 85721 NOTICE report was prepared 86 an account of work sponsored by the United Stater Government. Neither the United S t a m nor the United States Department of Encrwi, nor any of their employees, nor any of thelr contractors, Subcontractors, o r their employer, maker any warranty, exprels or Implied. or apumn my k@ liability or responsibility for the aceuraey. eompletencu or uvfulneu of any informtion, apparatus. product Process disclosed. or rtpreYnu that its ur would not infringe privately o m d righu. November 1978 Prepared f o r TIE UNITED STATES DEPARTMENT OF ENERGY Under Contract No. EN-77-S-02--000

104

Transition between mechanisms of laser-induced field-free molecular orientation  

E-Print Network (OSTI)

The transition between two distinct mechanisms for the laser-induced field-free orientation of CO molecules is observed via measurements of orientation revival times and subsequent comparison to theoretical calculations. In the first mechanism, which we find responsible for the orientation of CO up to peak intensities of 8 x 10^13 W/cm^2, the molecules are impulsively oriented through the hyperpolarizability interaction. At higher intensities, asymmetric depletion through orientation-selective ionization is the dominant orienting mechanism. In addition to the clear identification of the two regimes of orientation, we propose that careful measurements of the onset of the orientation depletion mechanism as a function of the laser intensity will provide a relatively simple route to calibrate absolute rates of non-perturbative strong-field molecular ionization.

Znakovskaya, Irina; De, Sankar; Li, Hui; Ray, Dipanwita; Corkum, Paul; Litvinyuk, Igor V; Cocke, C Lewis; Kling, Matthias F

2013-01-01T23:59:59.000Z

105

Detection of ultratrace levels of uranium in aqueous samples by laser-induced fluorescence spectrometry  

SciTech Connect

A new method of analysis for ultratrace quantities of ururanium in aqueous samples has been developed with a detection limit of 4 x 10/sup -14/M(10/sup -5/ ppb, 0.01 pg/mL). This detection level is considerably less than the average concentration of 0.1 ppb uranium found in natural groundwaters. The procedure consists of an initial coprecipitation of the solution uranium with calcium fluoride, calcination at 800/sup 0/C, and monitoring the uranium content by laser-induced fluorescence excitation (LIFE). Analytical data using this technique are presented for previously analyzed groundwater samples containing 10/sup -6/-10/sup -7/M uranium. The fluorescence yield dependence on calcination time and temperature and on cation and anion interferences is discussed.

Perry, D.L. (Univ. of California, Berkeley); Klainer, S.M.; Bowman, H.R.; Milanovich, F.P.; Hirschfeld, T.; Miller, S.

1981-06-01T23:59:59.000Z

106

A laser-induced repetitive fast neutron source applied for gold activation analysis  

SciTech Connect

A laser-induced repetitively operated fast neutron source was developed for applications in laser-driven nuclear physics research. The developed neutron source, which has a neutron yield of approximately 4 Multiplication-Sign 10{sup 5} n/pulse and can be operated up to a pulse repetition rate of 10 Hz, was applied for a gold activation analysis. Relatively strong delayed gamma spectra of the activated gold were measured at 333 keV and 355 keV, and proved the possibility of the neutron source for activation analyses. In addition, the nuclear reactions responsible for the measured gamma spectra of gold were elucidated by the 14 MeV fast neutrons resulting from the D(t,n)He{sup 4} nuclear reaction, for which the required tritium originated from the primary fusion reaction, D(d,p)T{sup 3}.

Lee, Sungman; Park, Sangsoon; Lee, Kitae; Cha, Hyungki [Quantum Optics Division, Korea Atomic Energy Research Institute, Daejeon 305-600 (Korea, Republic of)

2012-12-15T23:59:59.000Z

107

Sequential Printing by Laser-Induced Forward Transfer To Fabricate a Polymer Light-Emitting Diode Pixel  

E-Print Network (OSTI)

Sequential Printing by Laser-Induced Forward Transfer To Fabricate a Polymer Light-Emitting Diode-1015, Lausanne, Switzerland ABSTRACT: Patterned deposition of polymer light-emitting diode (PLED Organic light-emitting diodes (OLEDs) have been investigated in detail for nearly a quarter of a century,1

108

Red-green-blue polymer light-emitting diode pixels printed by optimized laser-induced forward transfer  

E-Print Network (OSTI)

Red-green-blue polymer light-emitting diode pixels printed by optimized laser-induced forward tri-color organic light-emitting diode (OLED) pixels. At reduced pressures, and with a defined donor already been used to fabricate basic small-molecule organic light-emitting diodes (OLEDs)2,3 and polymeric

109

Controlled Vortex Breakdown on Modified Delta Wings  

Science Conference Proceedings (OSTI)

This paper studies the effect of perturbation to the breakdown of the leading-edge vortices over delta wings. The passive perturbation in the normal direction is achieved by installing the hemisphere-like bulges on the delta wing along the projection ... Keywords: Bulge perturbation, Delta wing, Vortex breakdown

S. Srigrarom; N. Lewpiriyawong

2007-08-01T23:59:59.000Z

110

Final_Tech_Session_Schedule_and_Location.xls  

NLE Websites -- All DOE Office Websites (Extended Search)

and Nitrogen Using Laser-Induced Breakdown Spectroscopy (LIBS) Ronny D. Harris 1 , Michael H. Ebinger 1 , Clifton W. Meyer 1 and David A. Cremers 1 Earth and Environmental Sciences...

111

Vortex Breakdown in Atmospheric Columnar Vortices  

Science Conference Proceedings (OSTI)

Vortex breakdown occurs in tornadoes and waterspouts. This phenomenon may give information on the state and future behavior of those whirlwinds. Because of the rarity of recorded events, archival sources are consulted for qualitative descriptions ...

H. J. Lugt

1989-12-01T23:59:59.000Z

112

Spark gap with low breakdown voltage jitter  

SciTech Connect

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

Rohwein, Gerald J. (Albuquerque, NM); Roose, Lars D. (Albuquerque, NM)

1996-01-01T23:59:59.000Z

113

Surface breakdown igniter for mercury arc devices  

DOE Patents (OSTI)

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

Bayless, John R. (Malibu, CA)

1977-01-01T23:59:59.000Z

114

Humidity effects on wire insulation breakdown strength.  

SciTech Connect

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.

Appelhans, Leah

2013-08-01T23:59:59.000Z

115

Quantitative laser-induced incandescence measurements of soot in turbulent pool fires.  

DOE Green Energy (OSTI)

Laser-induced incandescence measurements have recently been obtained from 10% and 30% toluene in methanol blended fuel pool fires of 2-m diameter. Calibration of the instrument was performed using an ethylene/air laminar diffusion flame produced by a Santoro-type burner which allowed the extraction of absolute soot-volume-fractions from these images. Performance of the optical probe was characterized using the laminar diffusion flame and corrections were implemented for signal dependence upon detector gain, flat field, and location within the probe laser sheet when processing the images. Probability density functions of the soot-volume fraction were constructed for the blended fuels used in this study and the mean values were determined to be 0.0077 and 0.028 ppm for the 10% and 30% blended fuels, respectively. Signal trapping was estimated for the two types of blended fuel and it was determined to be negligible for the 10% toluene/methanol blend and require {approx}10% correction for the 30% toluene/methanol blend.

Frederickson, Kraig; Grasser, Thomas W.; Kearney, Sean Patrick

2009-12-01T23:59:59.000Z

116

A new post-column reactor-laser induced fluorescence detector for capillary electrophoresis  

Science Conference Proceedings (OSTI)

Capillary zone electrophoresis (CZE), a powerful separation method based on the differential migration of charged species under the influence of an electric field, has been widely used for separations covering from small ions to big biomolecules. Chapter 1 describes the method, then discusses detection of the separated analytes by laser induced fluorescence and by chemical derivatization, and the use of O-phthaldialdehyde (OPA) as a post-column reagent. Chapter 2 describes a post-column reactor which uses two narrow bore capillaries connected coaxially. This reactor differs from other coaxial reactors in terms of capillary dimensions, reagent flow control, ease of construction and most importantly, better limits of detection. The derivatization reagent is electroosmotically driven into the reaction capillary and the reagent flow rate is independently controlled by a high voltage power supply. Amino acids, amines and proteins, derivatized by OPA/2-mercaptoethanol using this post-column reactor coupled with LIF detection, show low attomole mass limits of detection, and for the first time, the authors demonstrate single cell capability with a post-column derivatization scheme. The single cell capability shows that this reactor could find applications in assaying non-fluorescent or electrochemically inactive components in individual biological cells in the future.

Zhang Liling

1996-01-02T23:59:59.000Z

117

Study on the effects of ion motion on laser-induced plasma wakes  

Science Conference Proceedings (OSTI)

A 2D analytical model is presented for the generation of plasma wakes (or bubbles) with an ultra-intense laser pulse by taking into account the response of plasma ions. It is shown that the effect of ion motion becomes significant at the laser intensity exceeding 10{sup 21} W/cm{sup 2} and plasma background density below 10{sup 19} cm{sup -3}. In this regime, ion motion tends to suppress the electrostatic field induced by charge separation and makes the electron acceleration less effective. As a result, the assumption of immobile ions overestimates the efficiency of laser wake-field acceleration of electrons. Based on the analytical model, the dynamics of plasma ions in laser-induced wake field is investigated. It is found that only one bubble appears as the plasmas background density exceeds the resonant density and the deposited laser energy is concentrated into the bubble, resulting in the generation of an ion bunch with extremely high energy density.

Zhou Suyun [Institute of Modern Optical Technologies, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006 (China); School of Materials Sciences and Engineering, Jiangxi Science and Technology Normal University, Nanchang 330013 (China); Yu Wei [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Science, Shanghai 201800 (China); Yuan Xiao [Institute of Modern Optical Technologies, Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006 (China); Xu Han [National Laboratory for Parallel and Distributed Processing, School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Cao, L. H.; Cai, H. B.; Zhou, C. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

2012-09-15T23:59:59.000Z

118

Underwater pressure amplification of laser-induced plasma shock waves for particle removal applications  

Science Conference Proceedings (OSTI)

Underwater amplification of laser-induced plasma (LIP)-generated transient pressure waves using shock tubes is introduced and demonstrated. Previously, it has been shown that LIP for noncontact particle removal is possible on the sub-100-nm level. This is now enhanced through shock tube utilization in a medium such as water by substantially increasing shock wave pressure for the same pulse energy. A shock tube constrains the volume and changes the propagation direction of the expanding plasma core by focusing a pulsed-laser beam inside a tube with a blind end, thus increasing the wave front pressure generated. Current amplification approach can reduce radiation exposure of the substrate from the shock wave because of the increased distance from the LIP core to the substrate provided by the increased pressure per unit pulse energy. For the same pulsed laser, with the aid of a shock tube, substantial levels of pressure amplitude amplification (8.95) and maximum pressure (6.48 MPa) are observed and reported.

Dunbar, Thomas J.; Cetinkaya, Cetin [Department of Mechanical and Aeronautical Engineering, Clarkson University, Potsdam, New York 13699-5725 (United States) and Center for Advanced Materials Processing, Clarkson University, Potsdam, New York 13699-5725 (United States)

2007-07-30T23:59:59.000Z

119

Estimating the pressure of laser-induced plasma shockwave by stimulated Raman shift of lattice translational modes  

Science Conference Proceedings (OSTI)

The current paper investigates stimulated Raman scattering (SRS) when laser-induced plasma is formed in heavy water by focusing an intense pulsed 532 nm Nd:YAG laser beam at room temperature. An unexpected low-frequency SRS line attributed to the lattice translational modes of ice-VII (D{sub 2}O) is observed. The pressure of the plasma shockwave is estimated using low-frequency SRS line shift.

Li Zhanlong [State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012 (China); College of Physics, Jilin University, Changchun 130012 (China); Shan Xiaoning; Li Zuowei; Zhou Mi; Men Zhiwei [College of Physics, Jilin University, Changchun 130012 (China); Cao Junsheng [State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Wang Yiding [College of Electronic Science and Engineering and Key Laboratory on Integrated Optoelectronics, Jilin University, Changchun 130012 (China); Sun Chenglin [State Key Laboratory of Superhard Materials, College of Physics, Jilin University, Changchun 130012 (China)

2012-07-09T23:59:59.000Z

120

Metal film deposition by laser breakdown chemical vapor deposition  

Science Conference Proceedings (OSTI)

Dielectric breakdown of gas mixtures can be used to deposit homogeneous thin films by chemical vapor deposition with appropriate control of flow and pressure conditions to suppress gas phase nucleation and particle formation. Using a pulsed CO/sub 2/ laser operating at 10.6 microns where there is no significant resonant absorption in any of the source gases, we have succeeded in depositing homogeneous films from several gas phase precursors by gas phase laser pyrolysis. Nickel and molybdenum from the respective carbonyls and tungsten from the hexafluoride have been examined to date. In each case the gas precursor is buffered to reduce the partial pressure of the reactants and to induce breakdown. The films are spectrally reflective and uniform over a large area. Films have been characterized by Auger electron spectroscopy, x-ray diffraction, pull tests, and resistivity measurements. The highest quality films have resulted from the nickel depositions. Detailed x-ray diffraction analysis of these films yields a very small domain size (approx. 50 A) consistent with rapid quenching from the gas phase reaction zone. This analysis also shows nickel carbide formation consistent with the temperature of the reaction zone and the Auger electron spectroscopy results which show some carbon and oxygen incorporation (8% and 1% respectively). Gas phase transport and condensation of the molybdenum carbonyl results in substantial carbon and oxygen contamination of the molybdenum films requiring heated substrates, a requirement not consistent with the goals of the program to maximize the quench rate of the deposition. Results from tungsten deposition experiments representing a reduction chemistry instead of the decomposition chemistry involved in the carbonyl experiments are also reported.

Jervis, T.R.

1985-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

Generation of laser-induced plasma in supercritical water and vibrational spectroscopic study of accompanying stimulated Raman scattering  

Science Conference Proceedings (OSTI)

We have formed a laser-induced plasma (LIP) in supercritical water (SCW) and studied associated molecular vibrations using spectroscopic methods. The accompanying forward and backward stimulated Raman scattering (SRS) of water molecules showed anisotropic behavior at supercritical conditions (>647 K and >22.1 MPa). The Raman shift of the backward SRS indicated that attractive interactions between water molecules and excess electrons generated by the LIP were dominant in the SCW. The backward SRS spectrum provided a microscopic view of the hydration environment around an excess electron, which is useful for controlling electron-driven chemical reactions and materials processing in SCW.

Yui, Hiroharu [Department of Chemistry, Faculty of Science, Tokyo University of Science, Kagurazaka 1-3, Shinjyuku-ku, Tokyo 162-8601 (Japan); PRESTO-JST, Sanbancho 5, Chiyoda-ku, Tokyo 102-0075 (Japan); Tomai, Takaaki; Sawada, Masayoshi; Terashima, Kazuo [Department of Advanced Materials Science, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8561 (Japan)

2011-08-29T23:59:59.000Z

122

Observation of Laser Induced Magnetization Dynamics in Co/Pd Multilayers with Coherent X-ray Scattering  

SciTech Connect

We report on time-resolved coherent x-ray scattering experiments of laser induced magnetization dynamics in Co/Pd multilayers with a high repetition rate optical pump x-ray probe setup. Starting from a multi-domain ground state, the magnetization is uniformly reduced after excitation by an intense 50 fs laser pulse. Using the normalized time correlation, we study the magnetization recovery on a picosecond timescale. The dynamic scattering intensity is separated into an elastic portion at length scales above 65 nm which retains memory of the initial domain magnetization, and a fluctuating portion at smaller length scales corresponding to domain boundary motion during recovery.

Wu, Benny

2012-04-05T23:59:59.000Z

123

RF Breakdown of Metallic Surfaces in Hydrogen  

DOE Green Energy (OSTI)

In earlier reports, microscopic images of the surfaces of metallic electrodes used in high-pressure gas-filled 805 MHz RF cavity experiments were used to investigate the mechanism of RF breakdown of tungsten, molybdenum, and beryllium electrode surfaces. Plots of remnants were consistent with the breakdown events being due to field emission, due to the quantum mechanical tunnelling of electrons through a barrier as described by Fowler and Nordheim. In the work described here, these studies have been extended to include tin, aluminium, and copper. Contamination of the surfaces, discovered after the experiments concluded, have cast some doubt on the proper qualities to assign to the metallic surfaces. However, two significant results are noted. First, the maximum stable RF gradient of contaminated copper electrodes is higher than for a clean surface. Second, the addition of as little as 0.01% of SF6 to the hydrogen gas increased the maximum stable gradient, which implies that models of RF breakdown in hydrogen gas will be important to the study of metallic breakdown.

BastaniNejad, M.; Elmustafa, A.A.; /Old Dominion U.; Yonehara, K.; Chung, M.; Jansson, A.; Hu, M.; Moretti, A.; Popovic, M.; /Fermilab; Alsharo'a, M.; Neubauer, M.; Sah, R.; /Muons Inc., Batavia

2009-05-01T23:59:59.000Z

124

Breakdown of Stokes-Einstein relation in supercooled water  

E-Print Network (OSTI)

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.

Pradeep Kumar

2007-02-06T23:59:59.000Z

125

Recent Studies of RF Breakdown Physics in Normal Conducting Cavities  

SciTech Connect

The operating accelerating gradient in normal conducting accelerating structures is often limited by rf breakdown. The behavior of the rf breakdown depends on multiple parameters, including the input rf power, rf circuit, cavity shape and material. Here we discuss recent experimental data and theoretical studies of rf breakdown physics.

Dolgashev, Valery; /SLAC

2012-06-11T23:59:59.000Z

126

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

Science Conference Proceedings (OSTI)

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

Wang Haifeng; Huang Zhimeng; Zhang Dayong; Luo Fei; Huang Lixian; Li Yanglong; Luo Yongquan; Wang Weiping; Zhao Xiangjie [Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang 621900 (China)

2011-12-01T23:59:59.000Z

127

Greatly Enhanced Detectability of Geothermal Tracers Through Laser-Induced Fluorescence  

DOE Green Energy (OSTI)

WE have successfully completed a four-year R and D project to greatly reduce the detection limit of fluorescent tracers through the use of emerging laser-excitation, optical fiber, and CCD-spectroscopy technologies. Whereas the efforts over the first two years were directed at demonstrating a reduction in the detection limit of fluorescent compounds by a factor of 100 and at identifying several new fluorescein-derived tracer candidates, our recent efforts were focused primarily on the field demonstration of new tracers having detection limits in the low parts-per-quadrillion range. During the summer of 2001, we initiated field tests at the Dixie Valley, Nevada and at the Beowawe, Nevada geothermal fields using very small quantities of the fluorescein-derivative 6-carboxyfluorescein. Subsequently, we succeeded in measuring sub-part-per-trillion quantities of that candidate tracer at both the Beowawe and Dixie Valley geothermal reservoirs-using approximately 530 g of tracer at each setting. Our studies indicate that we could have observed a breakthrough using only 0.53 g of 6-carboxyfluorescein. This represents a reduction by a factor of 170,000 below the mass of tracer used in a previous tracer test at Beowawe.

Peter Rose; Joel Harris; Phaedra Kilbourn; James Kleimeyer; Troy Carter

2002-10-30T23:59:59.000Z

128

Laser-induced incandescence and elastic-scattering measurements of particulate-matter volume fraction changes during passage through a dilution tunnel  

DOE Green Energy (OSTI)

Modern diesel engines produce far less mass of particulate matter than their predecessors, but this advance has been achieved at the expense of a significant increase in the number of sub-micron sized particles. This change in soot morphology has created the need for new instrumentation capable of measuring small volumes and sizes of particulate matter in a reasonable period of time, and preferably in real-time. Laser-induced incandescence and laser elastic scattering are complementary techniques suitable for this task. Optical measurements are presented for a diesel engine exhaust and compared with measurements performed using a scanning mobility particle sizer. This study investigates the effects of exhaust dilution and temperature control of the sampling system. It is also shown that laser-induced vaporization of low temperature volatile material is a potentially valuable technique for measuring the volatile component of exhaust particulate matter.

Robert M. Green; Peter O. Witze

2000-07-10T23:59:59.000Z

129

Laser-induced damage investigation at 1064 nmin KTiOPO4 crystals and its analogy with RbTiOPO4  

SciTech Connect

Bulk laser-induced damage at 1064 nm has been investigated in KTiOPO4 (KTP) and RbTiOPO4 (RTP) crystals with a nanosecond pulsed Nd:YAG laser. Both crystals belong to the same family. Throughout this study, their comparison shows a very similar laser-damage behavior. The evolution of the damage resistance under a high number of shots per site (10,000 shots) reveals a fatigue effect of KTP and RTP crystals. In addition, S-on-1 damage probability curves have been measured in both crystals for all combinations of polarization and propagation direction aligned with the principal axes of the crystals. The results show an influence of the polarization on the laser-induced damage threshold (LIDT), with a significantly higher threshold along the z axis, whereas no effect of the propagation direction has been observed. This LIDT anisotropy is discussed with regard to the crystallographic structure.

Hildenbrand, A.; Wagner, F. R.; Akhouayri, H.; Natoli, J.-Y.; Commandre, M.; Theodore, F.; Albrecht, H.

2009-07-20T23:59:59.000Z

130

Laser-induced fluorescence measurements and kinetic analysis of Si atom formation in a rotating disk chemical vapor deposition reactor  

SciTech Connect

An extensive set of laser-induced fluorescence (LIF) measurements of Si atoms during the chemical vapor deposition (CVD) of silicon from silane and disilane in a research rotating disk reactor are presented. The experimental results are compared in detail with predictions from a numerical model of CVD from silane and disilane that treats the fluid flow coupled to gas-phase and gas-surface chemistry. The comparisons showed that the unimolecular decomposition of SiH[sub 2] could not account for the observed gas-phase Si atom density profiles. The H[sub 3]SiSiH [leftrightarrow] Si + SiH[sub 4] and H[sub 3]SiSiH + SiH[sub 2] [leftrightarrow] Si + Si[sub 2]H[sub 6] reactions are proposed as the primary Si atom production routes. The model is in good agreement with the measured shapes of the Si atom profiles and the trends in Si atom density with susceptor temperature, pressure, and reactant gas mixture. 33 refs., 12 figs., 3 tabs.

Ho, P.; Coltrin, M.E.; Breiland, W.G. (Sandia National Lab., Albuquerque, NM (United States))

1994-10-06T23:59:59.000Z

131

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

SciTech Connect

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

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

2010-10-26T23:59:59.000Z

132

Trends in Ln(III) Sorption to Quartz Assessed by Molecular Dynamics Simulations and Laser Induced Flourescence Studies  

Science Conference Proceedings (OSTI)

Molecular dynamics simulations were performed to examine trends in trivalent lanthanide [Ln(III)] sorption to quartz surface SiOH0 and SiO- sites across the 4f period. Complementary laser induced fluorescence studies examined Eu(III) sorption to quartz at varying ionic strength such that the surface sorbed species could be extrapolated at zero ionic strength, the conditions under which the simulations are performed. This allowed for direct comparison of the data, enabling a molecular understanding of the surface sorbed species and the role of the ion surface charge density upon the interfacial reactivity. Thus, this combined theoretical and experimental approach aids in the prediction of the fate of trivalent radioactive contaminants at temporary and permanent nuclear waste storage sites. Potential of mean force molecular dynamics, as well as simulations of pre-sorbed Ln(III) species agrees with the spectroscopic study of Eu(III) sorption, indicating that strongly bound inner-sphere complexes are formed upon sorption to an SiO- site. The coordination shell of the ion contains 6-7 waters of hydration and it is predicted that surface OH groups dissociate from the quartz and bind within the inner coordination shell of Eu(III). Molecular simulations predict less-strongly bound inner2 sphere species in early lanthanides and more strongly bound species in late lanthanides, following trends in the ionic radius of the 4f ions. The participation of surface dissociated OHgroups within the inner coordination shell of the Ln(III) ion is, however, consistent across the series studied. Sorption to a fully protonated quartz surface is not predicted to be favorable by any Ln(III), except perhaps Lu.

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

2011-11-08T23:59:59.000Z

133

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

Science Conference Proceedings (OSTI)

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)

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

2008-11-15T23:59:59.000Z

134

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

Science Conference Proceedings (OSTI)

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)

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

2009-01-15T23:59:59.000Z

135

Wakefield Breakdown Test of a Diamond-Loaded Accelerating Structure  

NLE Websites -- All DOE Office Websites (Extended Search)

WAKEFIELD BREAKDOWN TEST OF A DIAMOND-LOADED ACCELERATING STRUCTURE S. Antipov, C. Jing, A. Kanareykin, P. Schoessow Euclid TechLabs LLC, Solon, OH, 44139 USA M. Conde, W. Gai, S....

136

Wakefield Breakdown Test of a Diamond-loaded Accelerating Structure...  

NLE Websites -- All DOE Office Websites (Extended Search)

WAKEFIELD BREAKDOWN TEST OF A DIAMOND-LOADED ACCELERATING STRUCTURE AT THE AWA S. Antipov, C. Jing, P. Schoessow, J. E. Butler, S. Zuo and A. Kanareykin, Euclid Techlabs LLC,...

137

Cone penetrometer fiber optic raman spectroscopy probe assembly  

DOE Patents (OSTI)

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.

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

2000-01-01T23:59:59.000Z

138

Transient Behaviour and Helium Discharge in Cryogenic Distribution Line (QRL) Headers Following Breakdown of Insulation Vacuum  

E-Print Network (OSTI)

Transient Behaviour and Helium Discharge in Cryogenic Distribution Line (QRL) Headers Following Breakdown of Insulation Vacuum

Chorowski, M

1997-01-01T23:59:59.000Z

139

Laser induced chemical reactions  

E-Print Network (OSTI)

of Basic Energy Sciences, Chemical Sciences Division of theINFRARED LASER ENHANCEMENT OF CHEMICAL REACTIONS A. B. C. D.Laser Inhibition of Chemical Reaction Effect of Isotopic

Orel, Ann E.

2010-01-01T23:59:59.000Z

140

REAL-TIME IN SITU DETECTION OF ORGANIC CONTAMINANTS BY LASER-INDUCED FLUORESCENCE SYSTEM. Final tropical report (Task 1.3).  

SciTech Connect

This report summarizes the results of the field demonstration of a laser-induced fluorescence (LIF) method for characterization of brownfields and other contaminated sites. The technology was provided and demonstrated by Dakota Technologies, Inc. (DTI), of Fargo, North Dakota. LIF generates continuous data on the distribution of polycyclic aromatic hydrocarbons (PAHs) within the soil profile. The sensor used to record real-time data is deployed into the soil using a modified truck-mounted Geoprobe percussion soil probing device. The summary of observations described in the following text represents an independent evaluation of the performance, usefulness, and economics of the demonstrated technology for characterization at PAH-contaminated sites.

Daniel J. Stepan; James A. Sorensen; Jaroslav Solc

1999-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

MHK Cost Breakdown Structure Draft | OpenEI Community  

Open Energy Info (EERE)

MHK Cost Breakdown Structure Draft MHK Cost Breakdown Structure Draft Home > Groups > Water Power Forum Kch's picture Submitted by Kch(24) Member 9 April, 2013 - 13:30 CBS current energy GMREC LCOE levelized cost of energy marine energy MHK ocean energy The generalized Cost Breakdown Structure (CBS) for marine and hydrokinetic (MHK) projects is a hierarchical structure designed to facilitate the collection and organization of lifecycle costs of any type of MHK project, including wave energy converters and current energy convertners. At a high level, the categories in the CBS will be applicable to all projects; at a detailed level, however, the CBS includes many cost categories that will pertain to one project but not others. It is expected that many of the detailed levels of the CBS will be populated with "NA" or left blank.

142

High-voltage atmospheric breakdown across intervening rutile dielectrics.  

SciTech Connect

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.

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

2013-09-01T23:59:59.000Z

143

Estimating building consumption breakdowns using ON/OFF state sensing and incremental sub-meter deployment  

Science Conference Proceedings (OSTI)

This paper considers the problem of estimating the power breakdowns for the main appliances inside a building using a small number of power meters and the knowledge of the ON/OFF states of individual appliances. First we solve the breakdown estimation ... Keywords: electric load estimation, electricity consumption monitoring, energy breakdowns

Deokwoo Jung; Andreas Savvides

2010-11-01T23:59:59.000Z

144

Atomic Spectroscopy Data Center  

Science Conference Proceedings (OSTI)

Atomic Spectroscopy Data Center. Summary: ... Atomic Spectroscopy Data Webpage. End Date: ongoing. Lead Organizational Unit: physlab. Contact. ...

2013-06-06T23:59:59.000Z

145

PHENIX Work Breakdown Structure. Cost and schedule review copy  

Science Conference Proceedings (OSTI)

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.

Not Available

1994-02-01T23:59:59.000Z

146

Vehicle Technologies Office: Fact #526: July 7, 2008 Price Breakdown for a  

NLE Websites -- All DOE Office Websites (Extended Search)

6: July 7, 2008 6: July 7, 2008 Price Breakdown for a Gallon of Gasoline and a Gallon of Diesel to someone by E-mail Share Vehicle Technologies Office: Fact #526: July 7, 2008 Price Breakdown for a Gallon of Gasoline and a Gallon of Diesel on Facebook Tweet about Vehicle Technologies Office: Fact #526: July 7, 2008 Price Breakdown for a Gallon of Gasoline and a Gallon of Diesel on Twitter Bookmark Vehicle Technologies Office: Fact #526: July 7, 2008 Price Breakdown for a Gallon of Gasoline and a Gallon of Diesel on Google Bookmark Vehicle Technologies Office: Fact #526: July 7, 2008 Price Breakdown for a Gallon of Gasoline and a Gallon of Diesel on Delicious Rank Vehicle Technologies Office: Fact #526: July 7, 2008 Price Breakdown for a Gallon of Gasoline and a Gallon of Diesel on Digg

147

 

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Analytical Development uses class III and IV high power lasers for numerous spectroscopy applications including Laser Induced Breakdown Analytical Development uses class III and IV high power lasers for numerous spectroscopy applications including Laser Induced Breakdown Spectroscopy (LIBS), Laser Ablation methods, Raman Spectroscopy, and several particle sizing and light scattering applications. To support the setup, staging, and maintenance of these systems, AD occupies labs 147 & 148 in 999-2W (& lab C143/147 in 773A). These labs have optical benches, laser warning lights, and door and window curtains for blocking open beam laser emissions. In addition, the instrumentation is usually made mobile or portable for field application where open beam is not allowed. This EEC covers general set-up, maintenance and troubleshooting of laser spectroscopy within Analytical Development. Set-up includes placement of lasers systems within proper laser controlled environments, mirror and lens placement

148

 

NLE Websites -- All DOE Office Websites (Extended Search)

Analytical Development uses class III and IV high power lasers for numerous spectroscopy applications including Laser Induced Breakdown Analytical Development uses class III and IV high power lasers for numerous spectroscopy applications including Laser Induced Breakdown Spectroscopy (LIBS), Laser Ablation methods, Raman Spectroscopy, and several particle sizing and light scattering applications. To support the setup, staging, and maintenance of these systems, AD occupies labs 147 & 148 in 999-2W (& lab C143/147 in 773A). These labs have optical benches, laser warning lights, and door and window curtains for blocking open beam laser emissions. In addition, the instrumentation is usually made mobile or portable for field application where open beam is not allowed. This EEC covers general set-up, maintenance and troubleshooting of laser spectroscopy within Analytical Development. Set-up includes placement of lasers systems within proper laser controlled environments, mirror and lens

149

Detailed modeling and laser-induced fluorescence imaging of nitric oxide in a NH(i)-seeded non-premixed methane/air flame  

Science Conference Proceedings (OSTI)

In this paper we study the formation of NO in laminar, nitrogen diluted methane diffusion flames that are seeded with ammonia in the fuel stream. We have performed numerical simulations with detailed chemistry as well as laser-induced fluorescence imaging measurements for a range of ammonia injection rates. For comparison with the experimental data, synthetic LIF images are calculated based on the numerical data accounting for temperature and fluorescence quenching effects. We demonstrate good agreement between measurements and computations. The LIF corrections inferred from the simulation are then used to calculate absolute NO mole fractions from the measured signal.The NO formation in both doped and undoped flames occurs in the flame sheet. In the undoped flame, four different mechanisms including thermal and prompt NO appear to contribute to NO formation. As the NH3 seeding level increases, fuel-NO becomes the dominant mechanism and N2 shifts from being a net reactant to being a net product. Nitric oxide in the undoped flame as well as in the core region of the doped flames are underpredicted by the model; we attribute this mainly to inaccuracies in the NO recycling chemistry on the fuel-rich side of the flame sheet.

Bell, John B.; Day, Marcus S.; Grcar, Joseph F.; Bessler, Wolfgang G.; Schulz, Christof; Glarborg, Peter; Jensen, Anker D.

2001-12-14T23:59:59.000Z

150

DOE G 430.1-1 Chp 5, Cost Codes and the Work Breakdown Structure  

Directives, Delegations, and Requirements

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 ...

1997-03-28T23:59:59.000Z

151

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

SciTech Connect

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.

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

2012-12-15T23:59:59.000Z

152

How natural is a natural interface? An evaluation procedure based on action breakdowns  

Science Conference Proceedings (OSTI)

This paper describes an issue-based method to evaluate the naturalness of an interface. The method consists of the execution of a series of tasks on that interface, which is subsequently systematically analyzed to identify breakdowns in the users' actions. ... Keywords: Action breakdown, Naturalness, Systematic video analysis, Usability

Luciano Gamberini; Anna Spagnolli; Lisa Prontu; Sarah Furlan; Francesco Martino; Beatriz Rey Solaz; Mariano Alcañiz; Josè Antonio Lozano

2013-01-01T23:59:59.000Z

153

Isotope effects and Born-Oppenheimer breakdown in excited singlet states of the lithium dimer  

E-Print Network (OSTI)

Isotope effects and Born-Oppenheimer breakdown in excited singlet states of the lithium dimer A-Oppenheimer breakdown in four singlet electronic states correlating with (2s 2s), (2s 2p), and (2p 2p) lithium atoms , and 1 1 g states of the lithium dimer. This paper also reports Fourier transform measurements of the B

Le Roy, Robert J.

154

Laser-induced chemical reactions. [H + H/sub 2/; F + H/sub 2/; H + HF; Cl + H/sub 2/; H + HCl; H + LiF  

DOE Green Energy (OSTI)

A classical model for the interaction of laser radiation with a molecular system is derived. This model is used to study the enhancement of a chemical reaction via a collision induced absorption. It was found that an infrared laser will in general enhance the rate of a chemical reaction, even if the reactants are infrared inactive. Results for an illustrative analytically solvable model are presented, as well as results from classical trajectory studies on a number of systems. The collision induced absorption spectrum in these systems can be written as the Fourier transform of a particular dipole correlation function. This is used to obtain the collision induced absorption spectrum for a state-selected, mono-energetic reactive collision system. Examples treated are a one-dimensional barrier problem, reactive and nonreactive collisions of H + H/sub 2/, and a modified H + H/sub 2/ potential energy surface which leads to a collision intermediate. An extension of the classical model to treat laser-induced electronically nonadiabatic collision processes is constructed. The model treats all degrees of freedom, molecular, electronic and radiation, in a dynamically consistent framework within classical mechanics. Application is made to several systems. Several interesting phenomena are discovered including a Franck-Condon-like effect causing maxima in the reaction probability at energies much below the classical threshold, laser de-enhancement of chemical reactions and an isotope effect. In order to assess the validity of the classical model for electronically nonadiabatic process (without a laser field), a model problem involving energy transfer in a collinear atom-diatom system is studied, and the results compared to the available quantum mechanical calculation. The calculations are in qualitative agreement.

Orel, A.E.

1980-12-01T23:59:59.000Z

155

Laser induced phosphorescence uranium analysis  

DOE Patents (OSTI)

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.

Bushaw, B.A.

1983-06-10T23:59:59.000Z

156

Breakdown of Cell Wall Nanostructure in Dilute Acid Pretreated Biomass  

Science Conference Proceedings (OSTI)

The generation of bioethanol from lignocellulosic biomass holds great promise for renewable and clean energy production. A better understanding of the complex mechanisms of lignocellulose breakdown during various pretreatment methods is needed to realize this potential in a cost and energy efficient way. Here, we use small-angle neutron scattering (SANS) to characterize morphological changes in switchgrass lignocellulose across molecular to sub-micron length scales resulting from the industrially-relevant dilute acid pretreatment method. Our results demonstrate that dilute acid pretreatment increases the cross-sectional radius of the crystalline cellulose fibril. This change is accompanied by removal of hemicellulose and the formation of Rg ~ 135 lignin aggregates. The structural signature of smooth cell wall surfaces is observed at length scales larger than 1000 , and it remains remarkably invariable during pretreatment. This study elucidates the interplay of the different biomolecular components in the break down process of switchgrass by dilute acid pretreatment. The results are important for the development of efficient strategies of biomass to biofuel conversion.

Pingali, Sai Venkatesh [ORNL; Urban, Volker S [ORNL; Heller, William T [ORNL; McGaughey, Joseph [ORNL; O'Neill, Hugh Michael [ORNL; Foston, Marcus B [ORNL; Myles, Dean A A [ORNL; Ragauskas, Arthur J [ORNL; Evans, Barbara R [ORNL

2010-01-01T23:59:59.000Z

157

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

DOE Green Energy (OSTI)

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.

Igor V. Litvinyuk, and Itzik Ben-Itzhak

2012-04-01T23:59:59.000Z

158

Structure test results from SLAC (NLCTA) show breakdown and damage at  

NLE Websites -- All DOE Office Websites (Extended Search)

test results from SLAC (NLCTA) show breakdown and damage at test results from SLAC (NLCTA) show breakdown and damage at gradients well below expectations from single cavity tests. The papers and presentations listed here illustrate some recent work on the topic. SLAC meeting notes are found here. Overview - Basic understanding of the role of particulate contaminants (Hasan Padamsee, PAC97) Literature study - Field emission and high voltage breakdown - (presentation by D. Burke 1996) References listed in D. Burke summary: SLAC Breakdown in S-band structures (Loew and Wang 1988) High Gradient studies in structures (Loew and Wang 1990) High Gradient tests (Wang et.al. 1994) Properties of Periodic Accelerating Structures for Linear Colliders (Wang 1989) Field emission in high gradient structures - (Loew and Wang -School 1997)

159

A Fire Risk Breakdown System for Electrical Power Lines in the North of Brazil  

Science Conference Proceedings (OSTI)

Anthropogenic or spontaneous fires (hotspots) are the main causes of unexpected breakdowns of electrical power lines in the North of Brazil. This research has tested, adapted and implemented a pre-operational system aiming to prevent electrical ...

Gutemberg Borges França; Antonio Nascimento de Oliveira; Célia Maria Paiva; Leonardo de Faria Peres; Michael Bezerra da Silva; Luciana Maria Temponi de Oliveira

160

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

E-Print Network (OSTI)

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 ...

Hwang, Jae-Won George, 1980-

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

Charge transport and breakdown physics in liquid/solid insulation systems  

E-Print Network (OSTI)

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 ...

Jadidian, Jouya

2013-01-01T23:59:59.000Z

162

An Observational Study of the Final Breakdown of the Southern Hemisphere Stratospheric Vortex in 2002  

Science Conference Proceedings (OSTI)

The 2002 Southern Hemisphere final warming occurred early, following an unusually active winter and the first recorded major warming in the Antarctic. The breakdown of the stratospheric polar vortex in October and November 2002 is examined using ...

Yvan J. Orsolini; Cora E. Randall; Gloria L. Manney; Douglas R. Allen

2005-03-01T23:59:59.000Z

163

Factors contributing to the breakdown of sodium beta-alumina  

DOE Green Energy (OSTI)

Clarification of the breakdown process occurring during charge transfer in sodium beta alumina solid electrolytes was derived from: (1) studying the effects of molten sodium contact at 350/sup 0/C on single crystal sodium beta alumina and polycrystalline sodium beta alumina; (2) determination of critical current density by monitoring acoustic emissions accompanying crack growth in sodium/sodium beta alumina/sodium cells subjected to linear current ramping at 1 mA cm/sup -2/ sec/sup -1/; (3) failure analysis conducted on cycled electrolytes, some from commercial sodium/sulfur cells, which had been subjected to up to 703 Ahr cm/sup -2/ of charge transfer. Gray coloration developing in beta aluminas in contact with molten sodium was found to be a consequence of formation, through reduction by sodium, of oxygen vacancies charge compensated by electrons. Electronic conductivity of the electrolyte increases as a result. No second phase formation was detected. Colored electrolytes from sodium/sulfur cells show evidence of a newly recognized degradation mechanism in which fracture occurs when sodium is reduced and deposited internally under pressure as metal in regions where an electronic conductivity gradient exists. Heating colored beta aluminas in air produces reoxidation and bleaching. Kinetics and other properties of the coloration and bleaching processes were determined. Critical current density was found to bear an inverse relation to average electrolyte grain size. Evidence was found in the cycled electrolytes for a slow crack growth mechanism and a progressive mode of degradation advancing from the sulfur electrode interface. Implications of the findings for the construction and operation of sodium/sulfur battery systems are discussed.

Buechele, A.C.

1982-05-01T23:59:59.000Z

164

Auger electron spectroscopy  

SciTech Connect

A review of Auger electron spectroscopy is presented. Methods, resolution, sensitivity, and uses are discussed. 30 references, 10 figures. (GHT)

Somorjai, G.A.

1980-12-01T23:59:59.000Z

165

RF Breakdown Studies Using a 1.3 GHZ Test Cell  

DOE Green Energy (OSTI)

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. Recent studies have shown that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas without the need for long conditioning times, because the dense gas can dramatically reduce dark currents and multipacting. In this project we use this high pressure technique to suppress effects of residual vacuum and geometry found in evacuated cavities to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. A 1.3-GHz RF test cell with replaceable electrodes (e.g. Mo, Cu, Be, W, and Nb) and pressure barrier capable of operating both at high pressure and in vacuum has been designed and built, and preliminary testing has been completed. A series of detailed experiments is planned at the Argonne Wakefield Accelerator. At the same time, computer simulations of the RF Breakdown process will be carried out to help develop a consistent physics model of RF Breakdown. In order to study the effect of the radiofrequency on RF Breakdown, a second test cell will be designed, fabricated, and tested at a lower frequency, most likely 402.5 MHz.

Sah, R.; Johnson, R.P.; Neubauer, M.; /Muons Inc., Batavia; Conde, M.; Gai, W.; /Argonne; Moretti, A.; Popovic, M.; Yonehara, K.; /Fermilab; Byrd, J.; Li, D.; /LBL, Berkeley; BastaniNejad, M.; /Old Dominion U.

2009-05-01T23:59:59.000Z

166

RF Breakdown Studies Using a 1.3-GHz Text Cell  

DOE Green Energy (OSTI)

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. Recent studies have shown that high gradients can be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas without the need for long conditioning times, because the dense gas can dramatically reduce dark currents and multipacting. In this project we use this high pressure technique to suppress effects of residual vacuum and geometry found in evacuated cavities to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. A 1.3-GHz RF test cell with replaceable electrodes (e.g. Mo, Cu, Be, W, and Nb) and pressure barrier capable of operating both at high pressure and in vacuum has been designed and built, and preliminary testing has been completed. A series of detailed experiments is planned at the Argonne Wakefield Accelerator. At the same time, computer simulations of the RF Breakdown process will be carried out to help develop a consistent physics model of RF Breakdown. In order to study the effect of the radiofrequency on RF Breakdown, a second test cell will be designed, fabricated, and tested at a lower frequency, most likely 402.5 MHz.

Sah, R.; Johnson, R. P.; Neubauer, M.; Conde, M.; Gai, W.; Moretti, A.; Popovic, M.; Yonehara, K.; Byrd, J.; Li, D.; BastaniNejad, M.; Elmustafa, M.

2009-05-04T23:59:59.000Z

167

The X$^1\\Sigma^+$ and a$^3\\Sigma^+$ states of LiCs studied by Fourier-transform spectroscopy  

E-Print Network (OSTI)

We present the first high-resolution spectroscopic study of LiCs. LiCs is formed in a heat pipe oven and studied via laser-induced fluorescence Fourier-transform spectroscopy. By exciting molecules through the X$^1\\Sigma^+$-B$^1\\Pi$ and X$^1\\Sigma^+$-D$^1\\Pi$ transitions vibrational levels of the X$^1\\Sigma^+$ ground state have been observed up to 3cm^{-1} below the dissociation limit enabling an accurate construction of the potential. Furthermore, rovibrational levels in the a$^3\\Sigma^+$ triplet ground state have been observed because the excited states obtain sufficient triplet character at the corresponding excited atomic asymptote. With the help of coupled channels calculations accurate singlet and triplet ground state potentials were derived reaching the atomic ground state asymptote and allowing first predictions of cold collision properties of Li + Cs pairs.

Staanum, P; Pashov, A; Tiemann, E; Knoeckel, Horst; Pashov, Asen; Staanum, Peter; Tiemann, Eberhard

2007-01-01T23:59:59.000Z

168

Breakdown Limits on Gigavolt-per-Meter Electron-Beam-Driven Wakefields in Dielectric Structures  

SciTech Connect

First measurements of the breakdown threshold in a dielectric subjected to GV/m wakefields produced by short (30-330 fs), 28.5 GeV electron bunches have been made. Fused silica tubes of 100 {micro}m inner diameter were exposed to a range of bunch lengths, allowing surface dielectric fields up to 27 GV/m to be generated. The onset of breakdown, detected through light emission from the tube ends, is observed to occur when the peak electric field at the dielectric surface reaches 13.8 {+-} 0.7 GV/m. The correlation of structure damage to beam-induced breakdown is established using an array of postexposure inspection techniques.

Thompson, M.C.; /UCLA /LLNL, Livermore; Badakov, H.; Cook, A.M.; Rosenzweig, J.B.; Tikhoplav, R.; Travish, G.; /UCLA; Blumenfeld, I.; Hogan, M.J.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; /SLAC; Muggli, P.; /Southern California U.; Scott, A.; /UC, Santa Barbara; Yoder, R.B.; /Manhattan Coll., Riverdale

2008-06-17T23:59:59.000Z

169

Microcontroller based system for electrical breakdown time delay measurement in gas-filled devices  

SciTech Connect

This paper presents realization of a digital embedded system for measuring electrical breakdown time delay. The proposed system consists of three major parts: dc voltage supply, analog subsystem, and a digital subsystem. Any dc power source with the range from 100 to 1000 V can be used in this application. The analog subsystem should provide fast and accurate voltage switching on the testing device as well as transform the signals that represent the voltage pulse on the device and the device breakdown into the form suitable for detection by a digital subsystem. The insulated gate bipolar transistor IRG4PH40KD driven by TC429 MOSFET driver is used for high voltage switching on the device. The aim of a digital subsystem is to detect the signals from the analog subsystem and to measure the elapsed time between their occurrences. Moreover, the digital subsystem controls various parameters that influence time delay and provides fast data storage for a large number of measured data. For this propose, we used the PIC18F4550 microcontroller with a full-speed compatible universal serial bus (USB) engine. Operation of this system is verified on different commercial and custom made gas devices with different structure and breakdown mechanisms. The electrical breakdown time delay measurements have been carried out as a function of several parameters, which dominantly influence electrical breakdown time delay. The obtained results have been verified using statistical methods, and they show good agreement with the theory. The proposed system shows good repeatability, sensitivity, and stability for measuring the electrical breakdown time delay.

Pejovic, Milic M.; Denic, Dragan B.; Pejovic, Momcilo M.; Nesic, Nikola T.; Vasovic, Nikola [Faculty of Electronic Engineering, University of Nis, Aleksandra Medvedeva 14, 18000 Nis (Serbia)

2010-10-15T23:59:59.000Z

170

X-Band Photonic Band-Gap Accelerator Structure Breakdown Experiment  

SciTech Connect

In order to understand the performance of photonic band-gap (PBG) structures under realistic high gradient, high power, high repetition rate operation, a PBG accelerator structure was designed and tested at X band (11.424 GHz). The structure consisted of a single test cell with matching cells before and after the structure. The design followed principles previously established in testing a series of conventional pillbox structures. The PBG structure was tested at an accelerating gradient of 65 MV/m yielding a breakdown rate of two breakdowns per hour at 60 Hz. An accelerating gradient above 110 MV/m was demonstrated at a higher breakdown rate. Significant pulsed heating occurred on the surface of the inner rods of the PBG structure, with a temperature rise of 85 K estimated when operating in 100 ns pulses at a gradient of 100 MV/m and a surface magnetic field of 890 kA/m. A temperature rise of up to 250 K was estimated for some shots. The iris surfaces, the location of peak electric field, surprisingly had no damage, but the inner rods, the location of the peak magnetic fields and a large temperature rise, had significant damage. Breakdown in accelerator structures is generally understood in terms of electric field effects. These PBG structure results highlight the unexpected role of magnetic fields in breakdown. The hypothesis is presented that the moderate level electric field on the inner rods, about 14 MV/m, is enhanced at small tips and projections caused by pulsed heating, leading to breakdown. Future PBG structures should be built to minimize pulsed surface heating and temperature rise.

Marsh, Roark A.; /MIT /MIT /NIFS, Gifu /JAERI, Kyoto /LLNL, Livermore; Shapiro, Michael A.; Temkin, Richard J.; /MIT; Dolgashev, Valery A.; Laurent, Lisa L.; Lewandowski, James R.; Yeremian, A.Dian; Tantawi, Sami G.; /SLAC

2012-06-11T23:59:59.000Z

171

A hybrid method for flowshops scheduling with condition-based maintenance constraint and machines breakdown  

Science Conference Proceedings (OSTI)

One of the most important assumptions in production scheduling is that the machines are permanently available without any breakdown. In the real world of scheduling, machines can be made unavailable due to various reasons such as preventive maintenance ... Keywords: Condition-based monitoring, Flowshop, Meta-heuristic, Preventive maintenance, Tauguchi

Ehram Safari; Seyed Jafar Sadjadi

2011-03-01T23:59:59.000Z

172

Leakage current and dielectric breakdown behavior in annealed SiO2 aerogel films  

E-Print Network (OSTI)

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

Jo, Moon-Ho

173

Geologic repository work breakdown structure and dictionary---Development and evaluation phase (PE-02)  

Science Conference Proceedings (OSTI)

Revision 2 of the OGR Work Breakdown Structure and Dictionary -- Development and Evaluation Phase (PE-02) supersedes Revision 1, August 1989, in its entirety. The revision is to delete the Exploratory Shaft Facility'' work scape and replace it with Exploratory Studies Facility'' work scape.

Not Available

1991-08-01T23:59:59.000Z

174

Twin logic gates: improved logic reliability by redundancy concerning gate oxide breakdown  

Science Conference Proceedings (OSTI)

Because of the aggressive scaling of integrated circuits and the given limits of atomic scales, circuit designers have to become more and more aware of the arising reliability and yield concerns. So far, only very little research efforts have been put ... Keywords: gate oxide breakdown, integrated circuit design, redundant systems, reliability

Hagen Saemrow; Claas Cornelius; Frank Sill; Andreas Tockhorn; Dirk Timmermann

2009-08-01T23:59:59.000Z

175

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

SciTech Connect

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.

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)

2013-01-28T23:59:59.000Z

176

Microsoft PowerPoint - Proceedings Cover Sheets  

NLE Websites -- All DOE Office Websites (Extended Search)

Total Soil Carbon and Other Nutrients Using Laser-Induced Breakdown Total Soil Carbon and Other Nutrients Using Laser-Induced Breakdown Spectroscopy (LIBS) R. D. Harris, P. J. Unkefer, M. H. Ebinger, C. W. Meyer, J. E. Fessenden-Rahn, and S. M. Clegg Introduction Developing accurate and rapid methods of measuring soil and plant nutrients is important for increasing soil productivity as well as reducing the costs of precision farming. Loss of soil carbon during the past 150 years has depleted many of the most productive soils and resulted in degradation of marginal soils. Organic matter is needed in soil to provide texture and prevent leaching of other essential nutrients. Terrestrial carbon management and sequestration produces a variety of benefits which include reclamation of degraded lands, increased soil productivity, reduced erosion, and potentially, slowing carbon

177

Animation of JILA Frequency Comb Spectroscopy Technique  

Science Conference Proceedings (OSTI)

Animation of JILA Frequency Comb Spectroscopy Technique. The new JILA "frequency comb spectroscopy" technique ...

2012-08-17T23:59:59.000Z

178

Microsoft Word - SEC J_Appendix F - National Work Breakdown Str_Negotiated  

National Nuclear Security Administration (NNSA)

F, Page 1 F, Page 1 SECTION J APPENDIX F NATIONAL WORK BREAKDOWN STRUCTURE The Department of Energy, National Nuclear Security Administration (DOE/NNSA), Office of Defense Programs, manages a large, complex, and diverse portfolio of weapons activities. To help facilitate and integrate the management of this portfolio, the Office of Defense Programs is establishing a National Work Breakdown Structure (NWBS). The NWBS will provide a consistent framework for planning, programming, budgeting, and evaluation of work required to execute the Defense Programs mission. Over time, the NWBS is anticipated to be expanded to all NNSA and DOE program activities. The NWBS will be contained in a relational database that serves as an easy-to-use tool for DOE/NNSA

179

Non-Gaussian Resistance Noise near Electrical Breakdown in Granular Materials  

E-Print Network (OSTI)

The distribution of resistance fluctuations of conducting thin films with granular structure near electrical breakdown is studied by numerical simulations. The film is modeled as a resistor network in a steady state determined by the competition between two biased processes, breaking and recovery. Systems of different sizes and with different levels of internal disorder are considered. Sharp deviations from a Gaussian distribution are found near breakdown and the effect increases with the degree of internal disorder. However, we show that in general this non-Gaussianity is related to the finite size of the system and vanishes in the large size limit. Nevertheless, near the critical point of the conductor-insulator transition, deviations from Gaussianity persist when the size is increased and the distribution of resistance fluctuations is well fitted by the universal Bramwell-Holdsworth-Pinton distribution.

C. Pennetta; E. Alfinito; L. Reggiani; S. Ruffo

2004-01-20T23:59:59.000Z

180

NIST Atomic Spectroscopy Data Center  

Science Conference Proceedings (OSTI)

Atomic Spectroscopy Data Center. ... Responds to user requests for data, literature references, and technical information. ...

2011-11-29T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

EMSL: Capabilities: Spectroscopy and Diffraction  

NLE Websites -- All DOE Office Websites (Extended Search)

Spectroscopy and Diffraction Spectroscopy and Diffraction Additional Information Meet the Spectroscopy and Diffraction Experts Related EMSL User Projects Spectroscopy and Diffraction Tools are Applied to all Science Themes Tutorial: XPS Tools for Surface Analysis Spectroscopy and Diffraction brochure EMSL's suite of spectroscopy and diffraction instruments allows users to study solid-, liquid-, and gas-phase sample structure and composition with remarkable resolution. Ideal for integrated studies, spectrometers and diffractometers are easily coupled with EMSL's computational and modeling capabilities, allowing users to apply a multifaceted research approach for experimental data interpretation and gain fundamental understanding of scientific problems. At EMSL, spectroscopy and diffraction instruments are

182

Genesis of Tropical Storm Eugene (2005) from Merging Vortices Associated with ITCZ Breakdowns. Part III: Sensitivity to Various Genesis Parameters  

Science Conference Proceedings (OSTI)

In this study, a series of sensitivity simulations is performed to examine the processes leading to the genesis of Tropical Storm Eugene (2005) from merging vortices associated with the breakdowns of the intertropical convergence zone (ITCZ) over ...

Chanh Q. Kieu; Da-Lin Zhang

2010-06-01T23:59:59.000Z

183

Technique Subgroupings Spectroscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

and NSLS-II beamlines according to DOE Technique Scheme and NSLS-II beamlines according to DOE Technique Scheme Technique Subgroupings Spectroscopy 01 - Low Energy Spectroscopy Infrared Photoemission U12IR, U4IR / MET* U5UA, U13 / ESM 02 - Soft X-Ray Spectroscopy Soft X-ray Spectroscopy Tender XAS U4B, U7A, X24A / SST, SSS* X15B, X19A / TES* 03 - Hard X-ray Spectroscopy EXAFS X3A, X3B, X11A, X11B, X18A, X18B, X23A2 / ISS, BMM, QAS*, XAS* 04 - Optics/Calibration/Metrology U3C,X8A/ OFT,MID Scattering 05 X-ray Diffraction X-Ray Powder Diffraction Extreme Conditions Energy Dispersive Micro-Beam Diffraction X7B,X10B,X14A,X16C,X17A / XPD,IXD* X17B2,X17B3,X17C / XPD, TEC*, 4DE* X17B1, X17B2 / NA X13B / MXD* 06 MX, footprinting Protein Crystallography X-ray footprinting X4A, X4C, X6A, X12B, X12C, X25, X29 / FMX, AMX, NYX;

184

Dielectric Breakdown  

Science Conference Proceedings (OSTI)

... High-voltage transformers contain oil as their insulating dielectric. ... The detailed electric-field distribution around the growing tree must be repeatedly ...

2011-01-12T23:59:59.000Z

185

Dielectric Breakdown  

Science Conference Proceedings (OSTI)

... Laying the model out on a large rectangular grid (128 X 128 X ... of streamer- tree growth have been approximated by different power-law responses ...

2012-12-12T23:59:59.000Z

186

2008 Vibrational Spectroscopy  

SciTech Connect

The conference focuses on using vibrational spectroscopy to probe structure and dynamics of molecules in gases, liquids, and interfaces. 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 systems.

Philip J. Reid

2009-09-21T23:59:59.000Z

187

Effect of high solenoidal magnetic fields on breakdown voltages of high vacuum 805 MHz cavities  

DOE Green Energy (OSTI)

There is an on going international collaboration studying the feasibility and cost of building a muon collider or neutrino factory [1,2]. An important aspect of this study is the full understanding of ionization cooling of muons by many orders of magnitude for the collider case. An important muon ionization cooling experiment, MICE [3], has been proposed to demonstrate and validate the technology that could be used for cooling. Ionization cooling is accomplished by passing a high-emittance muon beam alternately through regions of low Z material, such as liquid hydrogen, and very high accelerating RF Cavities within a multi-Tesla solenoidal field. To determine the effect of very large solenoidal magnetic fields on the generation of dark current, x-rays and on the breakdown voltage gradients of vacuum RF cavities, a test facility has been established at Fermilab in Lab G. This facility consists of a 12 MW 805 MHz RF station and a large warm bore 5 T solenoidal superconducting magnet containing a pill box type cavity with thin removable window apertures. This system allows dark current and breakdown studies of different window configurations and materials. The results of this study will be presented. The study has shown that the peak achievable accelerating gradient is reduced by a factor greater than 2 when solenoidal field of greater than 2 T are applied to the cavity.

Moretti, A.; Bross, A.; Geer, S.; Qian, Z.; /Fermilab; Norem, J.; /Argonne; Li, D.; Zisman, M.; /LBL, Berkeley; Torun, Y.; /IIT, Chicago; Rimmer, R.; /Jefferson Lab; Errede,; /Illinois U., Urbana

2005-10-01T23:59:59.000Z

188

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

Science Conference Proceedings (OSTI)

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.

Yeckel, Christopher; Curry, Randy [Department of Computer and Electrical Engineering, Center for Physical and Power Electronics, University of Missouri--Columbia, Columbia, Missouri 65211 (United States)

2011-09-15T23:59:59.000Z

189

On the delayed gas breakdown in a ringing theta-pinch with bias magnetic field  

Science Conference Proceedings (OSTI)

A single particle model and particle-in-cell simulations are used to elucidate the breakdown physics in a ringing theta-pinch with a bias magnetic field. Previous experimental results show that gas breakdown occurs when the bias magnetic field is nullified by the theta-pinch magnetic field. The analyses presented here agree with the experimental results and show that electron kinetic energy does not exceed the ionization threshold of deuterium until the net magnetic field is approximately zero. Despite the presence of a strong electric field, the gyromotion of electrons within the bias magnetic field prevents them from gaining energy necessary to ionize the gas. Parametric analysis of the peak electron energy as a function of the bias and pre-ionization magnetic fields reveals that: (1) when the bias magnetic field is Almost-Equal-To 97% of the pre-ionization magnetic field, peak electron energies are highly erratic resulting in poor overall ionization, and (2) full ionization with repeatable behavior requires a pre-ionization to bias magnetic field ratio of approximately 2 to 1 or higher.

Meeks, Warner C.; Rovey, Joshua L. [Mechanical and Aerospace Engineering, Missouri University of Science and Technology, Rolla, Missouri 65409-0050 (United States)

2012-05-15T23:59:59.000Z

190

NIST State-resolved Biomolecular Spectroscopies  

Science Conference Proceedings (OSTI)

State-resolved Spectroscopy of Biomolecules. Summary: ... For examples, see State-resolved terahertz spectroscopy of biomolecules. ...

2012-10-18T23:59:59.000Z

191

Nuclear reactivity control using laser induced polarization  

DOE Patents (OSTI)

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.

Bowman, Charles D. (Los Alamos, NM)

1991-01-01T23:59:59.000Z

192

Nuclear reactivity control using laser induced polarization  

DOE Patents (OSTI)

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.

Bowman, Charles D. (Los Alamos, NM)

1990-01-01T23:59:59.000Z

193

LASER INDUCED FLUORESCENCE OF TRAPPED MOLECULAR IONS  

E-Print Network (OSTI)

by Phil Eggers) produces a ttl signal with the same periodelectrical drawing. The ttl signal from this circuit (termedthe R.F. ttl) along with the pulse indicating when it is

Grieman, Frederick Joseph.

2010-01-01T23:59:59.000Z

194

Laser Induced Lightning: Thunderstorm Lightning Diversion  

Science Conference Proceedings (OSTI)

Lightning causes extensive damage to industrial and commercial facilities and residences. In addition, utilities lose revenue from lighting caused outages, resulting in substantial losses. This project deals with the development of a laser based system to divert lightning from striking susceptible facilities, such as nuclear power plants, critical substations and lines, operation control centers, and customer process control plants.

1999-11-29T23:59:59.000Z

195

LASER INDUCED FLUORESCENCE OF TRAPPED MOLECULAR IONS  

E-Print Network (OSTI)

System Laser Power Measurement Wavelength Calibration SystemLaser Power Measurement Wavelength Calibration PAGE Fluorescence Detection Systemmeasurement system. The actual time for initiation of the detection gate with respect to the laser

Grieman, Frederick Joseph.

2010-01-01T23:59:59.000Z

196

Laser-induced quantum pumping in graphene  

SciTech Connect

We investigate non-adiabatic electron pumping in graphene generated by laser irradiation with linear polarization parallel or perpendicular to the transport direction. Transport is dominated by the spatially asymmetric excitation of electrons from evanescent into propagating modes. For a laser with parallel polarization, the pumping response exhibits a subharmonic resonant enhancement which directly probes the Fermi energy; no such enhancement occurs for perpendicular polarization. The resonance mechanism relies on the chirality of charge carriers in graphene.

San-Jose, Pablo [Instituto de Estructura de la Materia (IEM-CSIC), Serrano 123, 28006 Madrid (Spain); Prada, Elsa; Kohler, Sigmund [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, 28049 Madrid (Spain); Schomerus, Henning [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom)

2012-10-08T23:59:59.000Z

197

Nuclear reactivity control using laser induced polarization  

DOE Patents (OSTI)

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 figs.

Bowman, C.D.

1989-05-26T23:59:59.000Z

198

Quantitative planar laser-induced fluorescence imaging of multi-component fuel/air mixing in a firing gasoline-direct-injection engine: Effects of residual exhaust gas on quantitative PLIF  

SciTech Connect

A study of in-cylinder fuel-air mixing distributions in a firing gasoline-direct-injection engine is reported using planar laser-induced fluorescence (PLIF) imaging. A multi-component fuel synthesised from three pairs of components chosen to simulate light, medium and heavy fractions was seeded with one of three tracers, each chosen to co-evaporate with and thus follow one of the fractions, in order to account for differential volatility of such components in typical gasoline fuels. In order to make quantitative measurements of fuel-air ratio from PLIF images, initial calibration was by recording PLIF images of homogeneous fuel-air mixtures under similar conditions of in-cylinder temperature and pressure using a re-circulation loop and a motored engine. This calibration method was found to be affected by two significant factors. Firstly, calibration was affected by variation of signal collection efficiency arising from build-up of absorbing deposits on the windows during firing cycles, which are not present under motored conditions. Secondly, the effects of residual exhaust gas present in the firing engine were not accounted for using a calibration loop with a motored engine. In order to account for these factors a novel method of PLIF calibration is presented whereby 'bookend' calibration measurements for each tracer separately are performed under firing conditions, utilising injection into a large upstream heated plenum to promote the formation of homogeneous in-cylinder mixtures. These calibration datasets contain sufficient information to not only characterise the quantum efficiency of each tracer during a typical engine cycle, but also monitor imaging efficiency, and, importantly, account for the impact of exhaust gas residuals (EGR). By use of this method EGR is identified as a significant factor in quantitative PLIF for fuel mixing diagnostics in firing engines. The effects of cyclic variation in fuel concentration on burn rate are analysed for different fuel injection strategies. Finally, mixture distributions for late injection obtained using quantitative PLIF are compared to predictions of computational fluid dynamics calculations. (author)

Williams, Ben; Ewart, Paul [Department of Physics, Oxford University, Parks Road, Oxford OX1 3PU (United Kingdom); Wang, Xiaowei; Stone, Richard [Department of Engineering Science, Oxford University, Parks Road, Oxford OX1 3PJ (United Kingdom); Ma, Hongrui; Walmsley, Harold; Cracknell, Roger [Shell Global Solutions (UK), Shell Research Centre Thornton, P. O. Box 1, Chester, CH1 3SH (United Kingdom); Stevens, Robert; Richardson, David; Fu, Huiyu; Wallace, Stan [Jaguar Cars, Engineering Centre, Abbey Road, Whitley, Coventry, CV3 4LF (United Kingdom)

2010-10-15T23:59:59.000Z

199

Unraveling EXAFS spectroscopy  

SciTech Connect

The past several years have witnessed the emergence of Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy from an esoteric technique to a widely available structural spectroscopic tool. Several in-depth review articles and books are available on the subject, but some aspects of theory or data reduction may be beyond the scope or need of the average chemist. In this article the authors will try to reduce the mystique surrounding EXAFS and clarify the terminology and concepts in the EXAFS literature. They will concentrate primarily on theory and data analysis and conclude with a few applications.

Fay, M.J.; Proctor, A.; Hoffman, D.P.; Hercules, D.M

1988-11-01T23:59:59.000Z

200

High voltage research (breakdown strengths of gaseous and liquid insulators) and environmental effects of dielectric gases. Semiannual report, October 1, 1979-March 31, 1980  

Science Conference Proceedings (OSTI)

Topics covered include basic studies of gaseous dielectrics, direct current breakdown strengths of gases/mixtures, environmental effects studies and decomposition analyses, impulse studies, breakdown strengths of binary mixtures with concentric cylinder geometry, and a discussion of the experimental apparatus. (GHT)

Christophorou, L.G.; James, D.R.; Pai, R.Y.

1980-08-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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201

Burgers-like equation for spontaneous breakdown of the chiral symmetry in QCD  

E-Print Network (OSTI)

We link the spontaneous breakdown of chiral symmetry in Euclidean QCD to the collision of spectral shock waves in the vicinity of zero eigenvalue of Dirac operator. The mechanism, originating from complex Burger's-like equation for viscid, pressureless, one-dimensional flow of eigenvalues, is similar to recently observed weak-strong coupling phase transition in large $N_c$ Yang-Mills theory. The spectral viscosity is proportional to the inverse of the size of the random matrix that replaces the Dirac operator in the universal (ergodic) regime. We obtain the exact scaling function and critical exponents of the chiral phase transition for the averaged characteristic polynomial for $N_c \\ge3$ QCD. We reinterpret our results in terms of known properties of chiral random matrix models and lattice data.

Jean-Paul Blaizot; Maciej A. Nowak; Piotr Warcho?

2013-03-10T23:59:59.000Z

202

Model of High Current Breakdown from Cathode Field Emission in Aged Wire Chambers  

SciTech Connect

Observing single electron pulses provides insight into the mechanism that leads to sudden high current jumps (breakdown) in aged wire chambers. This single electron activity is found to be consistent with the Fowler-Nordheim equation for field emission of electrons from a cathode surface in a high electric field. The high electric field arises from the positive ion buildup on a very thin insulating layer on the cathode surface. A model is presented to explain the transient behavior of single electron pulses in response to abrupt changes in chamber ionization, as well as the steady state rate during a long term aging run. The model is based on properties of the insulating layer (dielectric constant, conductivity, and hole-mobility) as well as the Fowler-Nordheim equation.

Boyarski, A

2004-02-25T23:59:59.000Z

203

To the electrostrictive mechanism of nanosecond-pulsed breakdown in liquid phase  

E-Print Network (OSTI)

In this study we have studied the initial stage of the nanosecond-pulsed discharge development in liquid phase. Modeling predicts that in the case of fast rising strong nonhomogeneous electric fields in the vicinity of high voltage pin electrode a region saturated with nanoscale non-uniformities may be developed. This phenomenon is attributed to the electrostriction mechanisms and may be used to explain development of breakdown in liquid phase. In this work, schlieren method was used in order to demonstrate formation of negative pressure region in liquids with different dielectric permittivity constants: water, ethanol and ethanol-water mixture. It is shown that this density perturbation, formed at the raising edge of the high voltage pulse, is followed by a generation of a shock wave propagating with the speed of sound away from the electrode, with negative pressure behind it.

Seepersad, Yohan; Pekker, Mikhail; Shneider, Mikhail N; Fridman, Alexander

2013-01-01T23:59:59.000Z

204

Enhancement of RF Breakdown Threshold of Microwave Cavities by Magnetic Insulation  

Science Conference Proceedings (OSTI)

Limitations on the maximum achievable accelerating gradient of microwave cavities can influence the performance, length, and cost of particle accelerators. Gradient limitations are believed to be initiated by electron emission from the cavity surfaces. Here, we show that field emission is effectively suppressed by applying a tangential magnetic field to the cavity walls, so higher gradients can be achieved. Numerical simulations indicate that the magnetic field prevents electrons leaving these surfaces and subsequently picking up energy from the electric field. Our results agree with current experimental data. Two specific examples illustrate the implementation of magnetic insulation into prospective particle accelerator applications. The ultimate goal of several research efforts is to integrate high-gradient radio-frequency (rf) structures into next generation particle accelerators. For instance, the Muon Accelerator Program is looking at developing low-frequency cavities for muon cooling, and the International Linear Collider is optimizing the performance of 1.3 GHz rf structures aimed at designing a 1 TeV electron-positron collider. Furthermore, the High Gradient RF Collaboration is examining high frequency (f > 10 GHz) structures intended for an electron-positron collider operating at energies in the TeV range. In all this research, the accelerating gradient will be one of the crucial parameters affecting their design, construction, and cost. Limitations from rf breakdown strongly influence the development of accelerators since it limits the machine's maximum gradient. The emission of electrons from the cavity surfaces seemingly is a necessary stage in the breakdown process, acting either as a direct cause of breakdown or as precursor for other secondary effects. Typically, electron currents arise from sharp edges or cracks on the cavities surfaces, where the strength of the electric field is strongly enhanced compared to that of the nominal field when the surfaces of the cavity are perfect planes. Subsequently, a stream of emitted electrons can be accelerated by the rf electric field toward the opposing cavity walls. Upon impact, they heat a localized region, resulting in the eventual breakdown by a variety of secondary mechanisms. Therefore, it is advantageous to develop techniques that could suppress field emission within rf cavities. It has been proposed that high voltages up to about a gigavolt range may be sustained in voltage transformers, by adopting the principle of magnetic insulation in ultrahigh vacuum. The basic idea is to suppress field emission by applying a suitably directed magnetic field of sufficient strength to force the electrons orbits back on to the rf emitting surface. More recently, it was shown that magnetic insulation could be very effective in suppressing field emission and multipacting in rectangular coupler waveguides. Hence, the question arises whether the same principle is applicable to rf accelerating structures. In this Letter, we shall consider application of the concept to low-frequency (201-805 MHz) muon accelerator cavities.

Stratakis, D.; Gallardo, J.; Palmer, R.B.

2011-03-28T23:59:59.000Z

205

Charmonium and Light Meson Spectroscopy  

E-Print Network (OSTI)

This talk reviews recent experimental results on selected topics in the spectroscopy of charmonia, charmonium-like states and light mesons.

Kai Zhu

2012-12-10T23:59:59.000Z

206

NIST: Atomic Spectroscopy Group - Homepage  

Science Conference Proceedings (OSTI)

... The program in atomic spectroscopy at NIST provides accurate reference data on spectral lines and energy levels for a wide variety of important ...

2013-07-31T23:59:59.000Z

207

High Breakdown ( > \\hbox {1500 V} ) AlGaN/GaN HEMTs by Substrate-Transfer Technology  

E-Print Network (OSTI)

In this letter, we present a new technology to increase the breakdown voltage of AlGaN/GaN high-electron-mobility transistors (HEMTs) grown on Si substrates. This new technology is based on the removal of the original Si ...

Lu, Bin

208

Spectroscopy of Solar Neutrinos  

E-Print Network (OSTI)

In the last years, liquid-scintillator detectors have opened a new window for the observation of low-energetic astrophysical neutrino sources. In 2007, the solar neutrino experiment Borexino began its data-taking in the Gran Sasso underground laboratory. High energy resolution and excellent radioactive background conditions in the detector allow the first-time spectroscopic measurement of solar neutrinos in the sub-MeV energy regime. The experimental results of the Beryllium-7 neutrino flux measurements as well as the prospects for the detection of solar Boron-8, pep and CNO neutrinos are presented in the context of the currently discussed ambiguities in solar metallicity. In addition, the potential of the future SNO+ and LENA experiments for high-precision solar neutrino spectroscopy will be outlined.

Michael Wurm; Franz von Feilitzsch; Marianne Goeger-Neff; Tobias Lachenmaier; Timo Lewke; Quirin Meindl; Randoplh Moellenberg; Lothar Oberauer; Walter Potzel; Marc Tippmann; Christoph Traunsteiner; Juergen Winter

2010-04-06T23:59:59.000Z

209

Observation of exclusively He-induced H emission in cooled laser plasma  

Science Conference Proceedings (OSTI)

An experiment was performed for the observation of H emission induced in a cooled laser-induced atmospheric pressure gas plasma of He atoms in their metastable excited state. The strong H emission detected clearly established, to the exclusion of other well known major excitation processes, the exclusive contribution of the He-induced excitation (HIE) mechanism. The process is suggested to take place by means of energy transfer from the excited He atoms to the H atoms via Penning collision induced ionization involving electron exchange. The result further shows that this mechanism may also work for elements other than H and thereby strongly suggests the use of ambient He gas to broaden and complement the applications of standard laser-induced breakdown spectroscopy.

Lie, Z. S.; Niki, H. [Program of Nuclear Power and Energy Safety Engineering, Graduate School of Engineering, Fukui University, Fukui 910-8507 (Japan); Kagawa, K. [Department of Physics, Faculty of Education and Regional Studies, Fukui University, 9-1 bunkyo 3-chome, Fukui 910-8507 (Japan); Tjia, May On [Physics of Magnetism and Photonics Research Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia); Hedwig, R. [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Pardede, M. [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Vilage, Tangerang, 15811 (Indonesia); Jobiliong, E. [Industrial Engineering Department, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Vilage, Tangerang, 15811 (Indonesia); Suliyanti, M. M. [Research Center for Physics, Indonesian Institute of Sciences, Kawasan PUSPIPTEK, Serpong Tangerang Selatan 15314, Banten (Indonesia); Abdulmadjid, S. N.; Kurniawan, K. H. [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia)

2011-05-15T23:59:59.000Z

210

High altitude atmospheric discharges according to the runaway air breakdown mechanism  

SciTech Connect

High altitude optical transients - red sprites, blue jets, and elves - are modeled in the context of the relativistic electron runaway air breakdown mechanism. These emissions are usually associated with large mesoscale convective systems (hereafter MCS). In thunderstorms cloud electrification proceeds over a time scale long enough to permit the conducting atmosphere above the cloud to polarize and short out the thunderstorm electric field. When a lightning strike rapidly neutralizes a cloud charge layer runaway driving fields can develop in the stratosphere and mesosphere. According to present simulations of the full runaway process the variety of observed optical emissions are due to the nature of the normal lightning event in the MCS that kick starts the runaway avalanche. In this paper the authors describe some details of the model, present the results of the evolution of the primary electron population, and summarize the initial conditions necessary for different types of discharges. Two companion papers present (a) the predicted optical, gamma ray, and radio emissions caused by these electrical discharges, and (b) the time evolution of the secondary electron population and its implications in terms of observables.

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

1997-04-01T23:59:59.000Z

211

VERY LOW FREQUENCY BREAKDOWN PROPERTIES OF ELECTRICAL INSULATION MATERIALS AT CRYOGENIC TEMPERATURES  

SciTech Connect

For long cables or equipment with large capacitance it is not always possible to conduct high voltage withstand at tests at 60 Hz due to limitations in charging currents of the power supply. Very low frequency (typically at a frequency of 0.1 Hz) has been used for conventional cables as a way of getting around the charging current limitation. For superconducting grid applications the same issues apply. However there is very little data at cryogenic temperatures on how materials perform at low frequency compared to 60 Hz and whether higher voltages should be applied when performing a high voltage acceptability test. Various materials including G10 (fiberglass reinforced plastic or FRP), Cryoflex (a tape insulation used in some high temperature superconducting cables), kapton (commonly used polyimide), polycarbonate, and polyetherimide, and in liquid nitrogen alone have been tested using a step method for frequencies of 60 Hz, 0.1 Hz, and dc. The dwell time at each step was chosen so that the aging factor would be the same in both the 60 Hz and 0.1 Hz tests. The data indicated that, while there is a small frequency dependence for liquid nitrogen, there are significant differences for the solid materials studied. Breakdown data for these materials and for model cables will be shown and discussed.

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

2010-01-01T23:59:59.000Z

212

Hadron Spectroscopy in COMPASS  

E-Print Network (OSTI)

The COmmon Muon and Proton Apparatus for Structure and Spectroscopy (COMPASS) is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron (SPS) aimed at studying the structure and spectrum of hadrons. In the naive Constituent Quark Model (CQM) mesons are bound states of quarks and antiquarks. QCD, however, predict the existence of hadrons beyond the CQM with exotic properties interpreted as excited glue (hybrids) or even pure gluonic bound states (glueballs). One main goal of COMPASS is to search for these states. Particularly interesting are so called spin-exotic mesons which have J^{PC} quantum numbers forbidden for ordinary q\\bar{q} states. Its large acceptance, high resolution, and high-rate capability make the COMPASS experiment an excellent device to study the spectrum of light-quark mesons in diffractive and central production reactions up to masses of about 2.5 GeV. COMPASS is able to measure final states with charged as well as neutral particles, so that resonances can be studied in different reactions and decay channels. During 2008 and 2009 COMPASS acquired large data samples using negative and positive secondary hadron beams on lH_2, Ni, and Pb targets. The presented overview of the first results from this data set focuses in particular on the search for spin-exotic mesons in diffractively produced \\pi^-\\pi^+\\pi^-, \\eta\\pi, \\eta'\\pi, and \\pi^-\\pi^+\\pi^-\\pi^+\\pi^- final states and the analysis of central-production of \\pi^+\\pi^- pairs in order to study glueball candidates in the scalar sector.

Boris Grube; for the COMPASS Collaboration

2013-01-31T23:59:59.000Z

213

Ring resonant cavities for spectroscopy  

DOE Patents (OSTI)

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.

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

1999-06-15T23:59:59.000Z

214

Suspension stirrer for NMR spectroscopy  

DOE Patents (OSTI)

This invention relates to nuclear magnetic resonance (NMR) spectroscopy and, more particularly, to the application of NMR spectroscopy to cell culture samples. A perfusion treatment system maintains microenvironmental conditions about cell spheroids during nuclear magnetic resonance (NMR) examination. A non-magnetic stirring assembly is inserted within a conventional NMR tube to continuously and uniformly supply a perfusate adjacent the spheroids. The perfusate is circulated during the spheroid stirring to maintain known perfusion conditions and eliminate artifacts from the NMR data. 4 figs.

Freyer, J.P; Coulter, J.R.

1990-12-02T23:59:59.000Z

215

Test 4, "NMR Spectroscopy", Chem416, FS93, Dr. Glaser --1 --Chemistry 416 "Spectroscopy"Chemistry 416 "Spectroscopy"  

E-Print Network (OSTI)

Test 4, "NMR Spectroscopy", Chem416, FS93, Dr. Glaser -- 1 -- Chemistry 416 "Spectroscopy "Take Home" Examination "NMR Spectroscopy" Hand-out: Wednesday, December 1, 1993 Collect: Friday Question 4 (13C Inc. Sys.) 20 Total 100 #12;Test 4, "NMR Spectroscopy", Chem416, FS93, Dr. Glaser -- 2

Glaser, Rainer

216

Rapid analysis of steels using laser-based techniques  

SciTech Connect

Based on the data obtained by this study, we conclude that laser-based techniques can be used to provide at least semi-quantitative information about the elemental composition of molten steel. Of the two techniques investigated here, the Sample-Only method appears preferable to the LIBS (laser-induced breakdown spectroscopy) method because of its superior analytical performance. In addition, the Sample-Only method would probably be easier to incorporate into a steel plant environment. However, before either technique can be applied to steel monitoring, additional research is needed.

Cremers, D.A.; Archuleta, F.L.; Dilworth, H.C.

1985-01-01T23:59:59.000Z

217

Investigating Ultrasonic Diffraction Grating Spectroscopy and ...  

Investigating Ultrasonic Diffraction Grating Spectroscopy and Reflection Techniques for Characterization Slurry Properties Investigating Ultrasonic Diffraction Grating

218

Spectroscopy (XSD) | Advanced Photon Source  

NLE Websites -- All DOE Office Websites (Extended Search)

Useful Links Useful Links Spectroscopy Group (X-ray Science Division) The Spectroscopy Group operates the Sector-20 bending magnet (BM) and insertion device (ID) beamlines, and the bending magnet beamline at Sector-9. Beamlines 20-ID (Undulator A) Supported Techniques ·X-ray absorption fine structure (XAFS) ·Surface Diffraction ·X-ray Raman Scattering ·Resonant X-ray Emission Spectroscopy ·Micro-XAFS ·Confocal X-ray microscopy ·Micro-fluorescence ·Micro-XRD Discipline ·Material Science ·Environmental Science ·Chemistry Click [20-ID] under "Beamlines" above for technical information 20-BM Supported Techniques X-ray absorption fine structure (XAFS) Micro-fluorescence Micro-XAFS Micro-diffraction Discipline ·Material Science ·Environmental Science ·Chemistry Click [20-BM] under "Beamlines" above for technical information

219

Environmental Spectroscopy and Biogeochemistry Facility  

NLE Websites -- All DOE Office Websites (Extended Search)

ES&B Overview ES&B Overview Section 2-2-1 Environmental Spectroscopy and Biogeochemistry Facility The Environmental Spectroscopy and Biogeochemistry (ES&B) Facility focuses on environ- mental molecular science and application of the fundamental concepts of physical chemistry to the study of chemical reactions in heterogeneous natural materials, with an emphasis on soil and subsurface systems. The ES&B Facility staff, along with other Pacific Northwest National Laboratory (PNNL) staff, form a multidisciplinary research team with expertise in chemistry, mineral physics, geochemistry, soil chemistry, microbiology, hydrology, and environmental engineering. Capabilities Capabilities are available for materials characterization, aqueous- and solid-phase speciation

220

Quantum spectroscopy of plasmonic nanostructures  

E-Print Network (OSTI)

We use frequency entangled photons, generated via spontaneous parametric down conversion, to measure the broadband spectral response of an array of gold nanoparticles exhibiting Fano-type plasmon resonance. Refractive index sensing of a liquid is performed by measuring the shift of the array resonance. This method is robust in excessively noisy conditions compared with conventional broadband transmission spectroscopy. Detection of a refractive index change is demonstrated with a noise level 70 times higher than the signal, which is shown to be inaccessible with the conventional transmission spectroscopy. Use of low photon fluxes makes this method suitable for measurements of photosensitive bio-samples and chemical substances.

Dmitry A. Kalashnikov; Zhenying Pan; Arseniy I. Kuznetsov; Leonid A. Krivitsky

2013-12-11T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

X-ray Absorption Spectroscopy  

SciTech Connect

This review gives a brief description of the theory and application of X-ray absorption spectroscopy, both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS), especially, pertaining to photosynthesis. The advantages and limitations of the methods are discussed. Recent advances in extended EXAFS and polarized EXAFS using oriented membranes and single crystals are explained. Developments in theory in understanding the XANES spectra are described. The application of X-ray absorption spectroscopy to the study of the Mn4Ca cluster in Photosystem II is presented.

Yano, Junko; Yachandra, Vittal K.

2009-07-09T23:59:59.000Z

222

Spectroscopy of transient neutral species via negative ion photoelectron spectroscopy  

SciTech Connect

Negative ion photoelectron spectroscopy has been used to study two types of transient neutral species: bound free radicals (NO{sub 2} and NO{sub 3}) and unstable neutral species ((IHI) and (FH{sub 2})). The negative ion time-of-flight photoelectron spectrometer used for these experiments is described in detail.

Weaver, A.

1991-12-01T23:59:59.000Z

223

Spectroscopy of transient neutral species via negative ion photoelectron spectroscopy  

Science Conference Proceedings (OSTI)

Negative ion photoelectron spectroscopy has been used to study two types of transient neutral species: bound free radicals (NO{sub 2} and NO{sub 3}) and unstable neutral species ([IHI] and [FH{sub 2}]). The negative ion time-of-flight photoelectron spectrometer used for these experiments is described in detail.

Weaver, A.

1991-12-01T23:59:59.000Z

224

Diagnosing breast cancer using diffuse reflectance spectroscopy and intrinsic fluorescence spectroscopy  

E-Print Network (OSTI)

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 ...

Fitzmaurice, Maryann

225

Ramsey spectroscopy with squeezed light  

E-Print Network (OSTI)

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.

Qu, Kenan

2013-01-01T23:59:59.000Z

226

DEVELOPMENTS IN HEAVY QUARKONIUM SPECTROSCOPY  

E-Print Network (OSTI)

­ 1­ DEVELOPMENTS IN HEAVY QUARKONIUM SPECTROSCOPY Written May 2012 by S. Eidelman (Budker Inst. Navas (Univ. Granada), and C. Patrignani (Univ. Genova, INFN). A golden age for heavy quarkonium physics at HERA and the Tevatron matured; and heavy-ion collisions at RHIC opened a window on the deconfinement

227

NMR Spectroscopy Protein-NMR  

E-Print Network (OSTI)

Keywords NMR Spectroscopy Protein-NMR Physical Organic Chemistry » Prof. Dr. Stefan Berger The research group of Prof. Dr. Stefan Berger focuses its work on: 1. Protein-NMR for the genera- tion of Protein-Structures. This includes application of all mod- ern 3D NMR pulse sequences for fully 15 N and 13

Schüler, Axel

228

The formation of a plasma channel in the optical breakdown of a gas by tubular Bessel beams  

Science Conference Proceedings (OSTI)

The plasma formed by the breakdown of gases (argon was used in the experiments, whereas argon and helium were considered in the calculations) at atmospheric pressure in light beams was studied experimentally and modelled numerically. The field amplitude in these beams was virtually constant in the direction of propagation and described by a high-order Bessel function in the radial direction. The initial stage in the evolution of a spark, when the tubular configuration of the heating-radiation caustic exerts the greatest influence on the characteristics of the plasma channel, was investigated. (interaction of laser radiation with matter. laser plasma)

Bychkov, S S; Gorlov, S V; Margolin, L Ya; Pyatnitskii, Lev N; Tal'virskii, A D; Shpatakovskaya, Galina V [Scientific Association for High Temperatures, Russian Academy of Sciences, Moscow (Russian Federation)

1999-03-31T23:59:59.000Z

229

High voltage research (breakdown strengths of gaseous and liquid insulators). Semiannual report, April 1--September 30, 1977  

DOE Green Energy (OSTI)

Direct current breakdown strength measurements on a large number of multicomponent gas mixtures at low (approximately less than 1 atm) and high (approximately less than 5 atm) pressures led to the discovery of many gas mixtures of electron-attaching gases and strongly electron-attaching gases with N/sub 2/ and C/sub 3/F/sub 8/ which are superior to SF/sub 6/. Of special significance are mixtures containing C/sub 4/F/sub 6/ (perfluoro-2-butyne). The breakdown strength of one such mixture (20 percent C/sub 4/F/sub 6/ to 80 percent SF/sub 6/) is approximately 30 percent higher than pure SF/sub 6/ under identical conditions, both at low (approximately 0.7 atm) and high (4.6 atm) pressures. Perfluorocyclohexene (C/sub 6/F/sub 10/) and C/sub 5/F/sub 8/ (perfluorocyclopentene) were found at low pressure (approximately 0.2 atm) to be, respectively, approximately 2.1 and 2.2 times better than SF/sub 6/ under comparable conditions; they both have a potential as additives in gas mixtures. The effect of the inelastic electron scattering properties of a gas via negative ion resonances in the low-energy range (1 to approximately 4 eV) on the breakdown strength has been demonstrated for H/sub 2/, N/sub 2/, and CO and binary mixtures of these with SF/sub 6/ and C/sub 4/F/sub 6/ (perfluoro-2-butyne). The construction of a new high pressure (to approximately 11 atm), variable temperature (-50/sup 0/C to + 150/sup 0/C) apparatus has been completed and a practical test facility utilizing cylindrical electrode geometries has been put into operation; the first results on the latter apparatus were on SF/sub 6/-N/sub 2/ and c-C/sub 4/F/sub 8/--N/sub 2/ mixtures. Studies of environmental effects of dielectric gases via their electron-impact-induced decompositions and analysis of their breakdown products have begun using mass spectrometry and gas chromatography; C/sub 4/F/sub 6/ (perfluoro-2-butyne) seems to be resistant to electron-impact-induced decomposition indicating long-term stability.

Christophorou, L. G.; James, D. R.; Pai, R. Y.; Mathis, R. A.; Pace, M. O.; Bouldin, D. W.; Christodoulides, A. A.; Chan, C. C.

1977-11-01T23:59:59.000Z

230

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

Science Conference Proceedings (OSTI)

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.

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

2001-09-01T23:59:59.000Z

231

Raman Spectroscopy for Experimental Investigation of Microscale ...  

Science Conference Proceedings (OSTI)

New Saccharification Process of Cellulosic Biomass by Microwave Irradiation · Novel Lamination Method for Large Armor Panels · Raman Spectroscopy for ...

232

Al composition dependence of breakdown voltage in Al{sub x}Ga{sub 1-x}N Schottky rectifiers  

SciTech Connect

Planar geometry, lateral Schottky rectifiers were fabricated on high resistivity Al{sub x}Ga{sub 1-x}N (x=0-0.25) epitaxial layers grown on sapphire substrates. The reverse breakdown voltages of unpassivated devices increased with Al composition, varying from 2.3 kV for GaN to 4.3 kV for Al{sub 0.25}Ga{sub 0.75}N. The reverse current-voltage (I-V) characteristics showed classical Shockley-Read-Hall recombination as the dominant mechanism, with I{proportional_to}V{sup 0.5}. The reverse current density in all diodes was in the range 5-10x10{sup -6} A cm{sup -2} at 2 kV. The use of p{sup +} guard rings was effective in preventing premature edge breakdown and with optimum ring width increased V{sub B} from 2.3 to 3.1 kV in GaN diodes. (c) 2000 American Institute of Physics.

Zhang, A. P. [Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611 (United States)] [Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611 (United States); Dang, G. [Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611 (United States)] [Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611 (United States); Ren, F. [Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611 (United States)] [Department of Chemical Engineering, University of Florida, Gainesville, Florida 32611 (United States); Han, J. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Polyakov, A. Y. [Institute of Rare Metals, Moscow 109017, Russia (Russian Federation)] [Institute of Rare Metals, Moscow 109017, Russia (Russian Federation); Smirnov, N. B. [Institute of Rare Metals, Moscow 109017, Russia (Russian Federation)] [Institute of Rare Metals, Moscow 109017, Russia (Russian Federation); Govorkov, A. V. [Institute of Rare Metals, Moscow 109017, Russia (Russian Federation)] [Institute of Rare Metals, Moscow 109017, Russia (Russian Federation); Redwing, J. M. [Epitronics, Phoenix, Arizona 85027 (United States)] [Epitronics, Phoenix, Arizona 85027 (United States); Cao, X. A. [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States)] [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Pearton, S. J. [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States)] [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States)

2000-03-27T23:59:59.000Z

233

Pressure-dependent electron attachment and breakdown strengths of unitary gases, and synergism of binary gas mixtures: a relationship  

SciTech Connect

The relationship between the pressure-dependent electron attachment rate constants (k/sub a/) which have been observed in 1-C/sub 3/F/sub 6/ and in several perfluoroalkanes, and the uniform field breakdown strengths (E/N)/sub lim/ in these gases is discussed. Measurements of the pressure dependence of k/sub a/ of OCS in a buffer gas of Ar are presented and the possible pressure dependence of (E/N)/sub lim/ in OCS is discussed. Uniform field breakdown measurements have been performed in C/sub 3/F/sub 8/, n-C/sub 4/F/sub 10/, and SO/sub 2/ over a range of gas pressures (3 less than or equal to P/sub T/ less than or equal to 290 kPa) and are reported. All three molecules have been found to possess pressure-dependent (E/N)/sub lim/ values. The various types of synergistic behavior which have been observed in binary gas dielectric mixtures are summarized and discussed. A new mechanism is outlined which can explain the synergism observed in several gas mixtures where the (E/N)/sub lim/ values of the mixutres are greater than those of the individual gas constituents. Model calculations are presented which support this mechanism, and can be used to explain the pressure-dependent synergistic effects which have been reported in 1-C/sub 3/F/sub 6//SF/sub 6/ gas mixture.

Hunter, S.R.; Christophorou, L.G.

1984-04-01T23:59:59.000Z

234

Light Hadron Spectroscopy and Charmonium  

E-Print Network (OSTI)

During the last few years there has been a renaissance in charm and charmonium spectroscopy with higher precision measurements at the $\\psi^{'}$ and $\\psi(3770)$ coming from BESII and CLEOc and many new discoveries coming from B-factories. In this paper, I review some new results on "classical" charmonium and $e^+ e^- \\to$ hadrons using B-factory Initial State Radiation and two photon events.

Frederick A. Harris

2008-10-17T23:59:59.000Z

235

spectroscopy  

Science Conference Proceedings (OSTI)

... of crystal spectrometers where the energy dispersion is polarization selective. ... by observing forbidden (M1) transitions within the ground term of ...

2010-12-07T23:59:59.000Z

236

Simultaneous beta and gamma spectroscopy  

DOE Patents (OSTI)

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.

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

2010-03-23T23:59:59.000Z

237

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

E-Print Network (OSTI)

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.

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

2011-07-22T23:59:59.000Z

238

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

DOE Green Energy (OSTI)

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.

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

2010-12-01T23:59:59.000Z

239

NIST Ultrafast Terahertz Spectroscopy and Imaging  

Science Conference Proceedings (OSTI)

... THz spectrometer for spectral determinations of samples (0.2 to 10 THz) and transient spectroscopy of bimolecular, photovoltaic, and materials ...

2013-09-20T23:59:59.000Z

240

High-Efficiency Neutron Detection and Spectroscopy  

Science Conference Proceedings (OSTI)

High-Efficiency Neutron Detection and Spectroscopy. ... such as searches for WIMP dark matter, neutrinoless double beta decay, and solar neutrinos. ...

2013-07-22T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


241

Optical sensing based on wavelength modulation spectroscopy  

DOE Patents (OSTI)

Techniques, apparatus and systems for using Wavelength Modulation Spectroscopy measurements to optically monitor gas media such as gases in gas combustion chambers.

Buckley, Steven G. (Redmond, WA); Gharavi, Mohammadreza (Tehran, IR); Borchers; Marco (Berlin, DE)

2011-06-28T23:59:59.000Z

242

Standoff Spectroscopy Using a Conditioned Target ...  

... and households Patent Charles W. Van Neste, Marissa E. Morales-Rodriguez, Lawrence R. Senesac, and Thomas G. Thundat, Standoff Spectroscopy Using ...

243

Photoelectron spectroscopy of negative ions  

Science Conference Proceedings (OSTI)

Ultraviolet photoelectron spectroscopy of negative ions was used to probe the anionic and neutral states of the halogen monoxides, halogen dioxides, halocarbenes, and fluorovinylidene species. Ions, created in a flowing afterglow source, were mass selected and photodetached by continuous monochromatic laser radiation, and the kinetic energy of the photodetached electrons were determined. The photoelectron spectra provide electronic and vibrational structure. Photoelectron spectra of the halogen monoxides yielded adiabatic electron affinities, neutral and anion frequencies, and spin-orbit splittings. Franck-Condon analyses provided the change in bond length between the neutral and anion species. Neutral heats of formation and dissociation energies were combined with electron affinities to determine anion heats of formation and dissociation energies. Adiabatic electron affinities, neutral vibrational frequencies and anion vibrational frequencies were determined from photoelectron spectra of OClO[sup [minus

Gilles, M.K.

1993-01-01T23:59:59.000Z

244

The COMPASS Hadron Spectroscopy Programme  

E-Print Network (OSTI)

COMPASS is a fixed-target experiment at the CERN SPS for the investigation of the structure and the dynamics of hadrons. The experimental setup features a large acceptance and high momentum resolution spectrometer including particle identification and calorimetry and is therefore ideal to access a broad range of different final states. Following the promising observation of a spin-exotic resonance during an earlier pilot run, COMPASS focused on light-quark hadron spectroscopy during the years 2008 and 2009. A data set, world leading in terms of statistics and resolution, has been collected with a 190GeV/c hadron beam impinging on either liquid hydrogen or nuclear targets. Spin-exotic meson and glueball candidates formed in both diffractive dissociation and central production are presently studied. Since the beam composition includes protons, the excited baryon spectrum is also accessible. Furthermore, Primakoff reactions have the potential to determine radiative widths of the resonances and to probe chiral pe...

Austregesilo, A

2012-01-01T23:59:59.000Z

245

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

DOE Green Energy (OSTI)

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.

Ahsan Choudhuri

2011-03-31T23:59:59.000Z

246

Ab initio Calculation of Thermodynamic Data for Oxygenated Hydrocarbon Fuels and Radial Breakdown Species: R(OMe)n  

DOE Green Energy (OSTI)

There has long been interest in the use of oxygenated hydrocarbon additives to conventional fuels. These oxygenates have been shown to reduce soot emissions in diesel engines and CO emissions in spark-ignition engines; and often allow diesel operation with decreased NO{sub x}. The current widely used additive, MTBE is targeted for elimination as a gasoline additive due to its damaging effects on the environment. This creates a need for alternative oxygenated additives; and more importantly, amplifies the importance to fully understand the thermochemical and kinetic properties on these oxyhydrocarbons fuels and for their intermediate and radical breakdown products. We use CBS-Q and density-functional methods with isodesmic reactions (with group balance when possible) to compute thermodynamic quantities for these species. We have studied hydrocarbons with multiple substituted methoxy groups. In several cases, multioxygenated species are evaluated that may have potential use as new oxygenated fuel additives. Thermodynamic quantities (H{sub 298}{sup 0}, S{sub 298}{sup 0}, C{sub p}(T)) as well as group additivity contributions for the new oxygenated groups are reported. We also report trends in bond-energies with increasing methoxy substitution.

Kubota, A; Pitz, W J; Westbrook, C K; Bozzelli, J; Glaude, P-A

2001-03-23T23:59:59.000Z

247

Spectroscopy of {sup 257}Rf.  

Science Conference Proceedings (OSTI)

The isotope {sup 257}Rf was produced in the fusion-evaporation reaction {sup 208}Pb({sup 50}Ti,n){sup 257}Rf. Reaction products were separated and identified by mass. Delayed spectroscopy of {sup 257}Rf and its decay products was performed. A partial decay scheme with configuration assignments is proposed based on hindrance factors. The excitation energy of the 1/2{sup +}[620] configuration in {sup 253}No is proposed. The energy of this 1/2{sup +} state in a series of N=151 isotones increases with nuclear charge, reflecting an increase in the N=152 gap. This gap is deduced to grow substantially from 850 to 1400 keV between Z=94 and 102. An isomeric state in {sup 257}Rf, with a half-life of 160{sub -31}{sup +42} {micro}s, was discovered by detecting internal conversion electrons followed by decay. It is interpreted as a three-quasiparticle high-K isomer. A second group of internal conversion electrons, with a half-life of 4.1{sub -1.3}{sup +2.4} s, followed by decay, was also observed. These events might originate from the decay of excited states in {sup 257}Lr, populated by electron-capture decay of {sup 257}Rf. Fission of {sup 257}Rf was unambiguously detected, with a branching ratio of b{sub Rf}{sup SF} = 0.02 {+-} 0.01.

Qian, J.; Heinz, A.; Khoo, T. L.; Janssens, R. V. F.; Peterson, D.; Seweryniak, D.; Ahmad, I.; Asai, M.; Back, B. B.; Carpenter, M. P.; Garnsworthy, A. B.; Greene, J. P.; Hecht, A. A.; Jiang, C. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; Robinson, A.; Savard, G.; Scott, R.; Vondrasek, R.; Wang, X.; Winkler, R.; Zhu, S.; Yale Univ.; Japan Atomic Energy Agency; Univ. of Surrey; Univ. of Maryland

2009-06-01T23:59:59.000Z

248

Spectroscopy of {sup 257}Rf  

Science Conference Proceedings (OSTI)

The isotope {sup 257}Rf was produced in the fusion-evaporation reaction {sup 208}Pb({sup 50}Ti,n){sup 257}Rf. Reaction products were separated and identified by mass. Delayed spectroscopy of {sup 257}Rf and its decay products was performed. A partial decay scheme with configuration assignments is proposed based on {alpha} hindrance factors. The excitation energy of the 1/2{sup +}[620] configuration in {sup 253}No is proposed. The energy of this 1/2{sup +} state in a series of N=151 isotones increases with nuclear charge, reflecting an increase in the N=152 gap. This gap is deduced to grow substantially from 850 to 1400 keV between Z=94 and 102. An isomeric state in {sup 257}Rf, with a half-life of 160{sub -31}{sup +42} {mu}s, was discovered by detecting internal conversion electrons followed by {alpha} decay. It is interpreted as a three-quasiparticle high-K isomer. A second group of internal conversion electrons, with a half-life of 4.1{sub -1.3}{sup +2.4} s, followed by {alpha} decay, was also observed. These events might originate from the decay of excited states in {sup 257}Lr, populated by electron-capture decay of {sup 257}Rf. Fission of {sup 257}Rf was unambiguously detected, with a branching ratio of b{sub Rf}{sup SF}=0.02{+-}0.01.

Qian, J.; Heinz, A.; Winkler, R. [WNSL, Yale University, New Haven, Connecticut 06511 (United States); Khoo, T. L.; Janssens, R. V. F.; Peterson, D.; Seweryniak, D.; Ahmad, I.; Back, B. B.; Carpenter, M. P.; Greene, J. P.; Jiang, C. L.; Kondev, F. G.; Lauritsen, T.; Lister, C. J.; Robinson, A.; Savard, G.; Scott, R.; Vondrasek, R.; Wang, X. [Argonne National Laboratory, Illinois 60439 (United States)] (and others)

2009-06-15T23:59:59.000Z

249

Method and apparatus for optoacoustic spectroscopy  

DOE Patents (OSTI)

A method and apparatus that significantly increases the sensitivity and flexibility of laser optoacoustic spectroscopy, with reduced size. With the method, it no longer is necessary to limit the use of laser optoacoustic spectroscopy to species whose absorption must match available laser radiation. Instead, "doping" with a relatively small amount of an optically absorbing gas yields optoacoustic signatures of nonabsorbing materials (gases, liquids, solids, and aerosols), thus significantly increasing the sensitivity and flexibility of optoacoustic spectroscopy. Several applications of this method are demonstated and/or suggested.

Amer, Nabil M. (Berkeley, CA)

1979-01-01T23:59:59.000Z

250

Temperature peaking at beginning of breakdown in 2.45 GHz pulsed off-resonance electron cyclotron resonance ion source hydrogen plasma  

SciTech Connect

An experimental study of temperature and density evolution during breakdown in off-resonance ECR hydrogen plasma is presented. Under square 2.45 GHz microwave excitation pulses with a frequency of 50 Hz and relative high microwave power, unexpected transient temperature peaks that reach 18 eV during 20 {mu}s are reported at very beginning of plasma breakdown. Decays of such peaks reach final stable temperatures of 5 eV at flat top microwave excitation pulse. Evidence of interplay between incoming power and duty cycle giving different kind of plasma parameters evolutions engaged to microwave coupling times is observed. Under relative high power conditions where short microwave coupling times are recorded, high temperature peaks are measured. However, for lower incoming powers and longer coupling times, temperature evolves gradually to a higher final temperature without peaking. On the other hand, the early instant where temperature peaks are observed also suggest a possible connection with preglow processes during breakdown in ECRIS plasmas.

Cortazar, O. D. [Universidad de Castilla-La Mancha. E.T.S.I.I., Camilo J. Cela s/n, 13071-C. Real (Spain); Megia-Macias, A.; Vizcaino-de-Julian, A. [E.S.S. Bilbao, Edificio Cosimet, Landabarri 2, 48940-Leioa, Vizcaya (Spain)

2012-10-15T23:59:59.000Z

251

Publications  

NLE Websites -- All DOE Office Websites (Extended Search)

7 results: 7 results: BibTex RIS RTF XML Sort by: Author Title Type [ Year (Desc) ] Filters: Author is Alberto J. Fernandez [Clear All Filters] 2009 Piscitelli, Vincent, Mauro A. Martinez, Alberto J. Fernandez, Jhanis J. Gonzalez, Xianglei Mao, and Richard E. Russo. "Double pulse laser induced breakdown spectroscopy; experimental study of lead emission intensity dependence on the wavelengths and sample matrix." Spectrochimica Acta Part B 64, no. 2 (2009): 147-154. 2008 Gonzalez, Jhanis J., Alberto J. Fernandez, Dayana Oropeza, Xianglei Mao, and Richard E. Russo. "Femtosecond laser ablation: Experimental study of the repetition rate influence on qualitative and quantitative ICP-MS performance." Spectrochimica Acta Part B-Atomic Spectroscopy 63 (2008):

252

Instrument Series: Spectroscopy and Diffraction XPS Imaging  

NLE Websites -- All DOE Office Websites (Extended Search)

XPS Imaging XPS Imaging The X-ray photoelectron spectroscopy (XPS) imaging system provides fast, quantitative, real-time parallel imaging with highest resolution spectroscopy at all analysis areas. In addition, the system is equipped with temperature programmed desorption (TPD), ultraviolet photoelectron spectroscopy (UPS), ion scattering spectroscopy (ISS), a cluster/Ar + ion gun, and a five-axis automated stage with variable temperature sample environment at the analysis chamber. The system is also integrated with a radial distribution chamber (RDC), a full-size glove box, and a cold-stage at the sample introduction for air-sensitive, liquid-semisolid, biological and environmental sample transfers. In addition, the RDC has a simple sample transfer mechanism to the

253

An Evolutionary Approach in Quantitative Spectroscopy  

Science Conference Proceedings (OSTI)

This paper describes investigations into using evolutionary search for quantitative spectroscopy. Given the spectrum (intensity × frequency) of a sample of material of interest, we would like to be able to infer the make-up of the material in terms ...

Phil Husbands; Pedro Paulo Balbi de Oliveira

1998-11-01T23:59:59.000Z

254

Meson Spectroscopy at CLAS and CLAS12  

Science Conference Proceedings (OSTI)

We report on meson spectroscopy using the CLAS at Jefferson Lab. We study photo?production of exotic mesons and strangeonia on the largest data sample ever to be produced at photon energies of about 5 GeV. We also describe an experiment to continue meson spectroscopy at CLAS12 (CLAS energy upgrade) using electroproduction at very low Q 2 (“quasireal photons”) up to photon energies of 10 GeV.

Carlos Salgado; The CLAS Collaboration

2011-01-01T23:59:59.000Z

255

Analysis of Combustion Efficiency Using Laser-Induced ...  

Science Conference Proceedings (OSTI)

A Solid State Thermoelectric Power Generator Prototype Designed to Recover Radiant Waste Heat ... An Overview of Energy Consumption and Waste Generation in the Recovery ... Global Primary Aluminium Industry 2010 Life Cycle Inventory.

256

DNA fragment sizing and sorting by laser-induced fluorescence  

DOE Patents (OSTI)

A method is provided for obtaining DNA fingerprints using high speed detection systems, such as flow cytometry to determine unique characteristics of DNA pieces from a selected sample. In one characterization the DNA piece is fragmented at preselected sites to produce a plurality of DNA fragments. The DNA piece or the resulting DNA fragments are treated with a dye effective to stain stoichiometrically the DNA fragments. The fluorescence from the dye in the stained fragments is then examined to generate an output functionally related to the number of nucleotides in each one of the DNA fragments. In one embodiment, the intensity of the fluorescence emissions from each fragment is directly proportional to the fragment length. Additional dyes can be bound to the DNA piece and DNA fragments to provide information additional to length information. Oligonucleotide specific dyes and/or hybridization probes can be bound to the DNA fragments to provide information on oligonucleotide distribution or probe hybridization to DNA fragments of different sizes.

Jett, J.H.; Hammond, M.L.; Keller, R.A.; Marrone, B.L.; Martin, J.C.

1992-12-31T23:59:59.000Z

257

Aerosol beam-focus laser-induced plasma spectrometer device  

SciTech Connect

An apparatus for detecting elements in an aerosol includes an aerosol beam focuser for concentrating aerosol into an aerosol beam; a laser for directing a laser beam into the aerosol beam to form a plasma; a detection device that detects a wavelength of a light emission caused by the formation of the plasma. The detection device can be a spectrometer having at least one grating and a gated intensified charge-coupled device. The apparatus may also include a processor that correlates the wavelength of the light emission caused by the formation of the plasma with an identity of an element that corresponds to the wavelength. Furthermore, the apparatus can also include an aerosol generator for forming an aerosol beam from bulk materials. A method for detecting elements in an aerosol is also disclosed.

Cheng, Meng-Dawn (Oak Ridge, TN)

2002-01-01T23:59:59.000Z

258

Laser-induced micron size clustering in thiophenol vapor  

SciTech Connect

Positively charged micron sized clusters are efficiently produced following irradiation of thiophenol vapor at 248 nm by a single KrF laser pulse of 30 ns duration. The production mechanism has been studied by examining the effect of N[sub 2], Ar, and He as diffusion media in mixtures with thiophenol, and by varying the laser pulse energy and excitation wavelength. A qualitative summary of possible mechanisms that may be responsible for the experimental results is presented providing a framework for understanding the observed cluster growth. The measurements indicate an optimum set of parameters for growth of large clusters and also show that the cluster charge can be controlled by selection of the buffer gas mixture.

Zafiropulos, V.; Kollia, Z.; Fotakis, C. (FORTH-Institute for Electronic Structure and Laser, P.O. Box 1527, GR 71110 Heraklion, Crete (Greece)); Stockdale, J.A.D. (L-463, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States))

1993-03-15T23:59:59.000Z

259

Spatial diagnostics of the laser induced lithium fluoride plasma  

SciTech Connect

We present spatial characteristics of the lithium fluoride plasma generated by the fundamental and second harmonic of a Nd:YAG laser. The plume emission has been recorded spatially using five spectrometers covering the spectral region from 200 nm to 720 nm. The electron density is measured from the Stark broadened line profile of the line at 610.37 nm, whereas the plasma temperature has been determined using the Boltzmann plot method including all the observed spectral lines of lithium. Both the plasma parameters; electron density and plasma temperature decrease with the increase of the distance from the target surface. The thermal conduction towards the target, the radiative cooling of the plasma, and the conversion of thermal energy into kinetic energy are the main mechanisms responsible for the spatially decrease of the plasma parameters.

Baig, M. A.; Qamar, Aisha; Fareed, M. A.; Anwar-ul-Haq, M.; Ali, Raheel [Atomic and Molecular Physics Laboratory, Department of Physics, Quaid-i-Azam University, 45320 Islamabad (Pakistan)

2012-06-15T23:59:59.000Z

260

UV laser induced photochromic centers in cerium doped calcium fluoride  

Science Conference Proceedings (OSTI)

The optical excitation of the lowest 4f to 5d transition in Ce/sup 3 +/:CaF/sub 2/ by the 308 mm output of a Xe-Cl excimer laser results in strong coloration. The centers created were found to be divalent cerium ions at cubic sites. The system exhibits photochromic properties; the crystal can be returned to the original transparent state by illuminating it with light which is absorbed by the divalent cerium ions. The creation process for these photochromic centers involves a resonant two-photon transition from the 4f ground state of the cerium ion to the conduction band of the CaF/sub 2/ host. The lowest 5d level of the cerium ion serves as the real intermediate state for this transition. The photoionized electron can be trapped by another trivalent cerium ion at a site of cubic symmetry. These impurity sites with O/sub h/ symmetry result when the charge compensator associated with the rare earth ion is somewhat removed from the cerium ion site. The charge compensator is needed to maintain charge neutrality in the crystal when a trivalent rare earth is substituted for a Ca ion in the host lattice. The absence of a local charge compensator at a Ce/sup 3 +/ site with O/sub h/ symmetry, provides a net positive Coulombic potential, which aids in the trapping of electrons from the conduction band. The capture of an electron by a cerium ion at cubic site, changes the valence state of the ion to Ce/sup 2 +/ which accounts for the coloration of the crystal after illumination with uv laser light. A model for the production of the photochromic centers is presented.

Pogatshnik, G.J.; Hamilton, D.S.

1987-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
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261

Orientation of molecules via laser-induced anti-alignment  

E-Print Network (OSTI)

We show that field-free molecular orientation induced by a half-cycle pulse may be considerably enhanced by an additional laser pulse inducing molecular anti-alignment. Two qualitatively different enhancement mechanisms are identified depending on the pulse order, and their effects are optimized with the help of quasi-classical as well as fully quantum models.

E. Gershnabel; I. Sh. Averbukh; R. J. Gordon

2005-09-14T23:59:59.000Z

262

COMPETING REACTION CHANNELS IN IR LASER INDUCED UNIMOLECULAR REACTIONS  

E-Print Network (OSTI)

the signal is due to thermal cooling. (Sjiun qjD) ^ijsueiuiendotheraic process giving thermal cooling (T* - 200 K ) andis followed by a slower, thermal cooling. oscillations are

Berman, M.R.

2010-01-01T23:59:59.000Z

263

Laser-induced spark ignition fundamental and applications  

SciTech Connect

Laser ignition has become an active research topic in recent years because it has the potential to replace the conventional electric spark plugs in engines that are required to operate under much higher compression ratios, faster compression rates, and much leaner fuel-to-air ratios than gas engines today. It is anticipated that the igniter in these engines will face with pressures as high as 50MPa and temperatures as high as 4000 K. Using the conventional ignition system, the required voltage and energy must be greatly increased (voltages in excess of 40 kV) to reliably ignite the air and fuel mixture under these conditions. Increasing the voltage and energy does not always improve ignitability but it does create greater reliability problem. The objective of this paper is to review past work to identify some fundamental issues underlying the physics of the laser spark ignition process and research needs in order to bring the laser ignition concept into the realm of reality.

Tran, P.X.

2006-05-01T23:59:59.000Z

264

Pulsed Laser Induced Self-Organization of Bilayer Liquids to ...  

Science Conference Proceedings (OSTI)

Abstract Scope, There are many applications in biology and electronics that can be enabled by nanoparticles which simultaneously exhibit ferromagnetism (FM) ...

265

Ultrafast Laser Induced Structures in ZnSe  

Science Conference Proceedings (OSTI)

High Thermal Energy Storage Density LiNO3-KNO3-NaNO2-KNO2 Quaternary Molten Salt System for Parabolic Trough Concentrating Solar Power Generation.

266

Purification of silane via laser-induced chemistry  

DOE Patents (OSTI)

Impurities such as PH.sub.3, AsH.sub.3, and B.sub.2 H.sub.6 may be removed from SiH.sub.4 by means of selective photolysis with ultraviolet radiation of the appropriate wavelength. An ArF laser operating at 193 nm provides an efficient and effective radiation source for the photolysis.

Clark, John H. (Los Alamos, NM); Anderson, Robert G. (Los Alamos, NM)

1979-01-01T23:59:59.000Z

267

Demonstration of Solar-Pumped Laser-Induced Magnesium ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, 2012 TMS Annual Meeting & Exhibition. Symposium , Magnesium Technology 2012. Presentation Title, Demonstration of ...

268

Picosecond laser induced electric field modulation of carotenoid absorption bands  

DOE Green Energy (OSTI)

We present a new and unique way of forming an intense electric field near a molecule in order to induce electrochromism. We have done this by creating an electron-hole pair within close proximity to, but electronically isolated form, a polarizable molecule. The molecular system that we have utilized consists of a zinc porphyrin -- pyromellitic diimide light induced charge transfer complex held rigidly proximate to a {beta}-carotene using a calix[4]arene linkage. The formation of the charge separated state of the porphyrin-diimide results in a dipole formed by the 8.4 {Angstrom} separation of the electron-hole pair. The electric field from this dipole was found to induce electrochromism in the carotene.

Gosztola, D.; Yamada, Hiroko; Wasielewski, M.R.

1994-04-01T23:59:59.000Z

269

Laser induced modification and ablation of InAs nanowires  

SciTech Connect

InAs nanowires were irradiated locally under an ambient condition using a focused laser beam, which led to laser ablation and thinning of the nanowires. We show that the laser beam can induce a reduction of the local As concentration in an InAs nanowire; the change leads to a significant decrease of local melting temperature of InAs, which results in the thinning and eventually breaking of the nanowire. The results indicate that chemical and mechanical modifications of an InAs nanowire can be accomplished by using a confocal laser beam, which may prove to be a convenient approach in fabricating nanostructural materials and nanodevices.

He Jiayu; Chen Pingping; Lu Wei; Dai Ning [Shanghai Institute of Technical Physics, Academy Science of China, Shanghai (China); Zhu Daming [Department of Physics, University of Missouri - Kansas City, Kansas City, Missouri 64110 (United States)

2012-05-01T23:59:59.000Z

270

Highly-sensitive Stoichiometric Analysis by Laser-induced ...  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2013. Symposium, Optical and X-ray Imaging Techniques for Material Characterization.

271

Ultrafast Spectroscopy of Warm Dense Matter  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast Spectroscopy of Warm Dense Matter Print Ultrafast Spectroscopy of Warm Dense Matter Print Being neither solid, liquid, gas, nor plasma, warm dense matter (WDM) occupies a no man's land in the map of material phases. Its temperature can range between that of planetary cores (tens of thousands K) to that of stellar cores (hundreds of thousands K). Not only is it prevalent throughout the universe, it is relevant to inertial confinement fusion (ICF) and material performance under extreme conditions. However, because of its extreme temperatures and pressures, WDM tends to be drastically transient and thus difficult to study in the laboratory. Now, researchers have set up ultrafast x-ray absorption spectroscopy at the ALS to measure the electronic structure of WDMs, demonstrating that fast-changing electron temperatures of matter under extreme conditions can be determined with picosecond resolution.

272

Spectroscopy and atomic force microscopy of biomass  

NLE Websites -- All DOE Office Websites (Extended Search)

Spectroscopy Spectroscopy and atomic force microscopy of biomass L. Tetard a,b , A. Passian a,b,n , R.H. Farahi a , U.C. Kalluri c , B.H. Davison c , T. Thundat a,b a Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA b Department of Physics, University of Tennessee, Knoxville, TN 37996, USA c Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, USA a r t i c l e i n f o Keywords: Atomic force microscopy Spectroscopy Plant cells Biomass Nanomechanics a b s t r a c t Scanning probe microscopy has emerged as a powerful approach to a broader understanding of the molecular architecture of cell walls, which may shed light on the challenge of efficient cellulosic ethanol production. We have obtained preliminary images of both Populus and switchgrass samples using atomic force microscopy (AFM). The results show distinctive features that are shared by switchgrass

273

Synchrotron Mossbauer Spectroscopy of powder samples  

SciTech Connect

Synchrotron Mossbauer Spectroscopy, SMS, is an emerging technique that allows fast and accurate determination of hyperfine field parameters similar to conventional Mossbauer spectroscopy with radioactive sources. This new technique, however, is qualitatively different from Mossbauer spectroscopy in terms of equipment, methodology, and analysis to warrant a new name. In this paper, the authors report on isomer shift and quadrupole splitting measurements of Mohr`s salt, Fe(NH{sub 4}){sub 2}(SO{sub 4}){sub 2}{center_dot}6H{sub 2}O for demonstration purposes. Theoretical calculations were performed and compared to experiments both in energy and time domain to demonstrate the influence of thickness distribution and preferential alignment of powder samples. Such measurements may prove to be useful when the data collection times are reduced to few seconds in the third generation, undulator based synchrotron radiation sources.

Alp, E.E.; Sturhahn, W.; Toellner, T.

1994-08-01T23:59:59.000Z

274

99thth Annual Proceedings of the Fred S. GrodinsFred S. Grodins  

E-Print Network (OSTI)

10:00 Lo, Joe Piezoelectric Optical MEMS Scanning Fluorescence Biosensor 10:15 Butte, Pramod Intra-Operative Time-Resolved Laser Induced Fluorescence Spectroscopy of Human Glial Tumors 10:30 Givrad, Tina-Resolved Laser Induced Fluorescence Spectroscopy of Human Glial Tumors 2 Chatterjee, Susmita Stimulus

Southern California, University of

275

Compressed sensing for multidimensional electronic spectroscopy experiments  

E-Print Network (OSTI)

Compressed sensing is a processing method that significantly reduces the number of measurements needed to accurately resolve signals in many fields of science and engineering. We develop a two-dimensional (2D) variant of compressed sensing for multidimensional electronic spectroscopy and apply it to experimental data. For the model system of atomic rubidium vapor, we find that compressed sensing provides significantly better resolution of 2D spectra than a conventional discrete Fourier transform from the same experimental data. We believe that by combining powerful resolution with ease of use, compressed sensing can be a powerful tool for the analysis and interpretation of ultrafast spectroscopy data.

J. N. Sanders; S. Mostame; S. K. Saikin; X. Andrade; J. R. Widom; A. H. Marcus; A. Aspuru-Guzik

2012-07-16T23:59:59.000Z

276

Spectroscopy of element 115 decay chains  

Science Conference Proceedings (OSTI)

A high-resolution a, X-ray and -ray coincidence spectroscopy experiment was conducted at the GSI Helmholtzzentrum fu r Schwerionenforschung. Thirty correlated a-decay chains were detected following the fusion-evaporation reaction 48Ca + 243Am. The observations are consistent with previous assignments of similar decay chains to originate from element Z = 115. The data includes first candidates of fingerprinting the decay step Mt --> Bh with characteristic X rays. For the first time, precise spectroscopy allows the derivation of excitation schemes of isotopes along the decay chains starting with elements Z > 112. Comprehensive Monte-Carlo simulations accompany the data analysis. Nuclear structure models provide a first level interpretation.

Rudolph, Dirk [Lund University, Sweden; Forsberg, U. [Lund University, Sweden; Golubev, P. [Lund University, Sweden; Sarmiento, L. G. [Lund University, Sweden; Yakushev, A. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Andersson, L.-L. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Di Nitto, A. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Duehllmann, Ch. E. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Gates, J. M. [Lawrence Berkeley National Laboratory (LBNL); Gregorich, K. E. [Lawrence Berkeley National Laboratory (LBNL); Gross, Carl J [ORNL; Hessberger, F. P. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Herzberg, R.-D [University of Liverpool; Khuyagbaatar, J. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Kratz, J. V. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Rykaczewski, Krzysztof Piotr [ORNL; Schaedel, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Aberg, S. [Lund University, Sweden; Ackermann, D. [GSI-Hemholtzzentrum fur Schwerionenforschung, Darmstadt, Germany; Block, M. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Brand, H. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Carlsson, B. G. [Lund University, Sweden; Cox, D. [University of Liverpool; Derkx, X. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Eberhardt, K. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Even, J. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Fahlander, C. [Lund University, Sweden; Gerl, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Jaeger, E. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kindler, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Krier, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kojouharov, I. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Kurz, N. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Lommel, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Mistry, A. [University of Liverpool; Mokry, C. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Nitsche, H. [Lawrence Berkeley National Laboratory (LBNL); Omtvedt, J. P. [Paul Scherrer Institut, Villigen, Switzerland; Papadakis, P. [University of Liverpool; Ragnarsson, I. [Lund University, Sweden; Runke, J. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Schaffner, H. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Schausten, B. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Thoerle-Pospiech, P. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Torres, T. [Gesellschaft fur Schwerionenforschung (GSI), Germany; Traut, T. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Trautmann, N. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany; Tuerler, A. [Paul Scherrer Institut, Villigen, Switzerland; Ward, A. [University of Liverpool; Ward, D. E. [Lund University, Sweden; Wiehl, N. [Johannes Gutenberg-Universitaet Mainz, Mainz, Germany

2013-01-01T23:59:59.000Z

277

A New Spin on Photoemission Spectroscopy  

SciTech Connect

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.

Advanced Light Source; Jozwiak, Chris

2008-12-18T23:59:59.000Z

278

Results and Frontiers in Lattice Baryon Spectroscopy  

SciTech Connect

The Lattice Hadron Physics Collaboration (LHPC) baryon spectroscopy effort is reviewed. To date the LHPC has performed exploratory Lattice QCD calculations of the low-lying spectrum of Nucleon and Delta baryons. These calculations demonstrate the effectiveness of our method by obtaining the masses of an unprecedented number of excited states with definite quantum numbers. Future work of the project is outlined.

Bulava, John; Morningstar, Colin [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Edwards, Robert; Richards, David [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Fleming, George [Yale University New Haven, CT 06520 (United States); Juge, K. Jimmy [Department of Physics, University of the Pacific, Stockton, CA 95211 (United States); Lichtl, Adam C. [RBRC, Brookhaven National Laboratory, Upton, NY 11973 (United States); Mathur, Nilmani [Tata Institute of Fundamental Research, Mumbai 40005 (India); Wallace, Stephen J. [University of Maryland, College Park, MD 20742 (United States)

2007-10-26T23:59:59.000Z

279

Baryon spectroscopy with CLAS at Jefferson Lab  

Science Conference Proceedings (OSTI)

A substantial part of the experimental efforts at the experimental Hall-B of Jefferson Laboratory is dedicated to this studies of light baryon spectroscopy. In this report a general overview of the experimental capabilities in the Experimental Hall-B will be presented together with preliminary results of recent double polarization measurements and finally overall status of the program.

Eugene Pasyuk, CLAS Collaboration

2012-04-01T23:59:59.000Z

280

Extensions of quartz-enhanced photoacoustic spectroscopy  

E-Print Network (OSTI)

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 ...

Masurkar, Amrita V

2009-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Photoelectron Spectroscopy of U Oxide at LLNL  

Science Conference Proceedings (OSTI)

In our laboratory at LLNL, an effort is underway to investigate the underlying complexity of 5f electronic structure with spin-resolved photoelectron spectroscopy using chiral photonic excitation, i.e. Fano Spectroscopy. Our previous Fano measurements with Ce indicate the efficacy of this approach and theoretical calculations and spectral simulations suggest that Fano Spectroscopy may resolve the controversy concerning Pu electronic structure and electron correlation. To this end, we have constructed and commissioned a new Fano Spectrometer, testing it with the relativistic 5d system Pt. Here, our preliminary photoelectron spectra of the UO{sub 2} system are presented. X-ray photoelectron spectroscopy has been used to characterize a sample of UO{sub 2} grown on an underlying substrate of Uranium. Both AlK{alpha} (1487 eV) and MgK{alpha} (1254 eV) emission were utilized as the excitation. Using XPS and comparing to reference spectra, it has been shown that our sample is clearly UO{sub 2}.

Tobin, J G; Yu, S; Chung, B W; Waddill, G D

2010-03-02T23:59:59.000Z

282

Lateral Al{sub x}Ga{sub 1-x}N power rectifiers with 9.7 kV reverse breakdown voltage  

SciTech Connect

Al{sub x}Ga{sub 1-x}N (x=0--0.25) Schottky rectifiers were fabricated in a lateral geometry employing p{sup +}-implanted guard rings and rectifying contact overlap onto an SiO{sub 2} passivation layer. The reverse breakdown voltage (V{sub B}) increased with the spacing between Schottky and ohmic metal contacts, reaching 9700 V for Al{sub 0.25}Ga{sub 0.75}N and 6350 V for GaN, respectively, for 100 {mu}m gap spacing. Assuming lateral depletion, these values correspond to breakdown field strengths of {<=}9.67x10{sup 5}Vcm{sup -1}, which is roughly a factor of 20 lower than the theoretical maximum in bulk GaN. The figure of merit (V{sub B}){sup 2}/R{sub ON}, where R{sub ON} is the on-state resistance, was in the range 94--268 MWcm-2 for all the devices.

Zhang, A. P.; Johnson, J. W.; Ren, F.; Han, J.; Polyakov, A. Y.; Smirnov, N. B.; Govorkov, A. V.; Redwing, J. M.; Lee, K. P.; Pearton, S. J.

2001-02-05T23:59:59.000Z

283

Depth-resolved cathodoluminescence spectroscopy of silicon supersaturated with sulfur  

E-Print Network (OSTI)

We investigate the luminescence of Si supersaturated with S (Si:S) using depth-resolved cathodoluminescence spectroscopy and secondary ion mass spectroscopy as the S concentration is varied over 2 orders of magnitude ...

Fabbri, Filippo

284

Electric Cell-impedance Spectroscopy at the Biological-inorganic ...  

Science Conference Proceedings (OSTI)

Presentation Title, Electric Cell-impedance Spectroscopy at the Biological- inorganic Interface, Shewanella Oneidensis - Gold, for Microbial Fuel Cell ...

285

Time-resolved multiple probe spectroscopy  

SciTech Connect

Time-resolved multiple probe spectroscopy combines optical, electronic, and data acquisition capabilities to enable measurement of picosecond to millisecond time-resolved spectra within a single experiment, using a single activation pulse. This technology enables a wide range of dynamic processes to be studied on a single laser and sample system. The technique includes a 1 kHz pump, 10 kHz probe flash photolysis-like mode of acquisition (pump-probe-probe-probe, etc.), increasing the amount of information from each experiment. We demonstrate the capability of the instrument by measuring the photolysis of tungsten hexacarbonyl (W(CO){sub 6}) monitored by IR absorption spectroscopy, following picosecond vibrational cooling of product formation through to slower bimolecular diffusion reactions on the microsecond time scale.

Greetham, G. M.; Sole, D.; Clark, I. P.; Parker, A. W.; Pollard, M. R.; Towrie, M. [Central Laser Facility, Science and Technology Facilities Council, Research Complex at Harwell, Rutherford Appleton Laboratory, Harwell, Oxfordshire, OX11 0QX (United Kingdom)

2012-10-15T23:59:59.000Z

286

Charge exchange recombination spectroscopy on fusion devices  

Science Conference Proceedings (OSTI)

For fusion, obtaining reliable measurements of basic plasma parameters like ion and electron densities and temperatures is a primary goal. For theory, measurements are needed as a function of time and space to understand plasma transport and confinement with the ultimate goal of achieving economic nuclear fusion power. Electron profile measurements and plasma spectroscopy for the plasma ions are introduced. With the advent of Neutral Beam auxiliary plasma heating, Charge Exchange Recombination Spectroscopy provides accurate and time resolved measurements of the ions in large volume fusion devices. In acknowledgement of Nicol Peacock's role in the development of these techniques, still at the forefront of plasma fusion research, this paper describes the evolution of this diagnostic method.

Duval, B. P. [Centre de Recherches en Physique des Plasmas, EPFL, Lausanne (Switzerland)

2012-05-25T23:59:59.000Z

287

NIR Spectroscopy Development and Alternate Technology Uses  

Science Conference Proceedings (OSTI)

This report describes tests conducted to further develop a near-infrared (NIR) optical spectroscopy system designed to remotely detect corrosion on transmission line conductors. Besides evaluating the performance of the system on additional conductors, researchers refined the design of the prototype system in preparation for field testing.BackgroundCorrosion of the core of the aluminum conductor steel-reinforced (ACSR) conductors used in transmission lines is ...

2012-12-12T23:59:59.000Z

288

Publications  

NLE Websites -- All DOE Office Websites (Extended Search)

7 results: 7 results: BibTex RIS RTF XML Sort by: Author Title Type [ Year (Desc) ] Filters: Author is Costas P. Grigoropoulos [Clear All Filters] 2010 Owens, Travis, Samuel S. Mao, Erin K. Canfield, Costas P. Grigoropoulos, Xianglei Mao, and Richard E. Russo. "Ultrafast thin-film laser-induced breakdown spectroscopy of doped oxides." Applied Optics 49 (2010): C67-C69. Barcelo, Steven J., Matthew Rogers, Costas P. Grigoropoulos, and Samuel S. Mao. "Hydrogen Storage property of sandwiched magnesium hydride naoparticle thin film." International Journal of Hydrogen Energy (2010). 2009 Rogers, Matthew, Steven J. Barcelo, Xiaobo Chen, Thomas J. Richardson, Vincent Berube, Gang Chen, Mildred S. Dresselhaus, Costas P. Grigoropoulos, and Samuel S. Mao. "Hydrogen Storage Characteristics of Nanograined

289

U  

NLE Websites -- All DOE Office Websites (Extended Search)

4, 2008 4, 2008 Dustin McIntyre, a mechanical engineer at the U.S. Department of Energy's National Energy Technology Laboratory (NETL), is one of the inventors of a laser spark distribution and ignition system developed at NETL which has recently been issued a patent. f al electrical spark plugs. McIntyre, a resident of Morgantown, WV, received his BS degrees in electrical engineering and computer engineering and MS and PhD in mechanical engineering from West Virginia University in Morgantown, WV. Producing a high peak power laser spark from a single low power pulse, this laser spark distribution and ignition system has application in natural gas-fueled reciprocating engines, turbine combustors, explosives, and laser- induced breakdown spectroscopy diagnostic sensors. The laser spark plug

290

Microsoft PowerPoint - Hanson_LIBS_IPRC  

NLE Websites -- All DOE Office Websites (Extended Search)

Effect Effect of Temperature Variation on LIBS Spectra of Molten Salts Cynthia Hanson and Supathorn Phongikaroon Nuclear Engineering Program, University of Idaho Jeremy J. Hatch and Jill R. Scott Interfacial Chemistry, Idaho National Laboratory International Pyroprocessing Research Conference 2012 8-29-12 Agenda * Mark-IV Electrorefiner * Motivation * Overview of LIBS (Laser-induced Breakdown Spectroscopy) * Project Objective * Experimental Set-up and Method Development * Results * Summary and Future Work 2 Mark-IV Electrorefiner * Processes used nuclear fuel (UNF) * Uranium from UNF is electrochemically transferred through the salt forming deposits on the cathode * Build up of fission products, transuranics, etc. inhibits efficiency and creates liabilities 3 Challenge for in-situ Electrorefiner Analysis 4 * No current method for real time analysis of salt * 500 ï‚°C operating

291

Feedstock Quality Factor Calibration and Data Model Development  

DOE Green Energy (OSTI)

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.

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

2010-05-01T23:59:59.000Z

292

Monitoring changes in soil carbon resulting from intensive production, a non-traditional agricultural methodology.  

Science Conference Proceedings (OSTI)

New Mexico State University and a group of New Mexico farmers are evaluating an innovative agricultural technique they call Intensive Production (IP). In contrast to conventional agricultural practice, IP uses intercropping, green fallowing, application of soil amendments and soil microbial inocula to sequester carbon as plant biomass, resulting in improved soil quality. Sandia National Laboratories role was to identify a non-invasive, cost effective technology to monitor soil carbon changes. A technological review indicated that Laser Induced Breakdown Spectroscopy (LIBS) best met the farmers' objectives. Sandia partnered with Los Alamos National Laboratory (LANL) to analyze farmers' test plots using a portable LIBS developed at LANL. Real-time LIBS field sample analysis was conducted and grab samples were collected for laboratory comparison. The field and laboratory results correlated well implying the strong potential for LIBS as an economical field scale analytical tool for analysis of elements such as carbon, nitrogen, and phosphate.

Dwyer, Brian P.

2013-03-01T23:59:59.000Z

293

Bipin Bihari resume  

NLE Websites -- All DOE Office Websites (Extended Search)

Bipin Bihari Bipin Bihari Argonne National Laboratory Energy Systems Division 9700 South Cass Avenue, Building 362 Argonne, IL 60439 phone: 630/252-6492, fax: 630/252-3443 e-mail: bihari@anl.gov Professional Experience ï‚· 2004-Present. Argonne National Laboratory o Designing fiber optic laser delivery for a laser based ignition application in a large bore multi-cylinder reciprocation natural gas engine o Developing optical diagnostics techniques for natural gas engines o Using laser induced breakdown spectroscopy as a diagnostic tool in engines ï‚· 1997-2003. Sr. Scientist/Small Business Innovation Research (SBIR) Program manager, Omega Optics, Inc./Radiant Photonics, Austin, Texas/ Microelectronics Research Center, University of Texas-Austin, Texas

294

Laser Spark Distribution and Ignition System  

NLE Websites -- All DOE Office Websites (Extended Search)

Spark Distribution and Ignition System Spark Distribution and Ignition System Opportunity The Department of Energy's National Energy Technology Laboratory (NETL) is seeking licensing partners interested in implement- ing United States Patent Number 7,421,166 entitled "Laser Spark Distribution and Ignition System." Disclosed in this patent is NETL's laser spark distribution and ignition system, which reduces the high-power optical requirements normally needed for such a system by using optical fibers to deliver low-peak-energy pumping pulses to a laser amplifier or laser oscillator. Laser spark generators then produce a high-peak-power laser spark from a single low power pulse. The system has ap- plications in natural gas fueled reciprocating engines, turbine combustors, explosives, and laser induced breakdown spectroscopy diagnostic sensors.

295

Photoelectron spectroscopy of supersonic molecular beams  

DOE Green Energy (OSTI)

A new technique for performing high resolution molecular photoelectron spectroscopy is described, beginning with its conceptual development, through the construction of a prototypal apparatus, to the initial applications on a particularly favorable molecular system. The distinguishing features of this technique are: (1) the introduction of the sample in the form of a collimated supersonic molecular beam; and (2) the use of an electrostatic deflection energy analyzer which is carefully optimized in terms of sensitivity and resolution. This combination makes it possible to obtain photoelectron spectra at a new level of detail for many small molecules. Three experiments are described which rely on the capability to perform rotationally-resolved photoelectron spectroscopy on the hydrogen molecule and its isotopes. The first is a measurement of the ionic vibrational and rotational spectroscopic constants and the vibrationally-selected photoionization cross sections. The second is a determination of the photoelectron asymmetry parameter, ..beta.., for selected rotational transitions. The third is an investigation of the rotational relaxation in a free jet expansion, using photoelectron spectroscopy as a probe of the rotational state population distributions. In the closing chapter an assessment is made of the successes and limitations of the technique, and an indication is given of areas for further improvement in future spectrometers.

Pollard, J.E.

1982-05-01T23:59:59.000Z

296

Work Breakdown Structure and Plant/Equipment Designation System Numbering Scheme for the High Temperature Gas- Cooled Reactor (HTGR) Component Test Capability (CTC)  

SciTech Connect

This white paper investigates the potential integration of the CTC work breakdown structure numbering scheme with a plant/equipment numbering system (PNS), or alternatively referred to in industry as a reference designation system (RDS). Ideally, the goal of such integration would be a single, common referencing system for the life cycle of the CTC that supports all the various processes (e.g., information, execution, and control) that necessitate plant and equipment numbers be assigned. This white paper focuses on discovering the full scope of Idaho National Laboratory (INL) processes to which this goal might be applied as well as the factors likely to affect decisions about implementation. Later, a procedure for assigning these numbers will be developed using this white paper as a starting point and that reflects the resolved scope and outcome of associated decisions.

Jeffrey D Bryan

2009-09-01T23:59:59.000Z

297

Issues in Light Meson Spectroscopy: The Case for Meson Spectroscopy at Cebaf  

E-Print Network (OSTI)

I review some outstanding issues in meson spectroscopy. The most important qualitative issue is whether hadrons with explicit gluonic degrees of freedom exist. To answer this question requires a much better understanding of conventional $q\\bar{q}$ mesons. I therefore begin by examining the status of conventional meson spectroscopy and how the situation can be improved. The expected properties of gluonic excitations are discussed with particular emphasis on hybrids to give guidance to experimental searches. Multiquark systems are commented upon as they are likely to be important in the mass region under study and will have to be understood better. In the final section I discuss the opportunities that CEBAF can offer for the study of meson spectroscopy.

Stephen Godfrey

1994-06-10T23:59:59.000Z

298

Observations of Ferroelastic Switching by Raman Spectroscopy  

E-Print Network (OSTI)

Thermal barrier coatings (TBCs) have become an important part of turbine technology by providing thermal protection to the underlying metallic components. These coatings are typically made from a zirconia-based ceramics which have a low thermal conductivity and thermal expansion coefficients similar to those of the superalloys. Early failure in these coatings is most often due to foreign object damage and erosion resulting in delamination and spallation. To protect against these types of failure, new materials with increased toughness are needed. There are two main toughening mechanisms in ceramics: transformation toughening, which is limited to low temperature applications and ferroelastic toughening which is accessible at all temperatures. Ferroelastic toughening occurs when the c-axis of the tetragonal grain undergoes reorientation under the application of an external stress. In this study, ferroelastic toughening is examined by Raman spectroscopy. It is shown that by using polarized confocal Raman spectroscopy one can not only observed the ferroelastic process, but also measure the parameters that control the increase in toughness observed. Ferroelastic toughening was observed in two ways in the 18mol% ceria stabilized zirconia (18CSZ) samples studied here. Samples were either exposed to indentation damage or uniaxial loading. In both of these cases maps of the ceramic surface were taken using Raman spectroscopy following loading and the relative intensities of the tetragonal peaks were analyzed. The resulting intensity profiles were used to monitor the reorientation of domains corresponding to ferroelastic toughening. Changes in domain orientation were observed that corresponded to the reorientation of domains along cracks as well as on a larger scale along those cracks. Domain reorientation was also observed under uniaxial loading and the stresses required for domain formation and movement were measured.

Bolon, Amy Marie

2011-12-01T23:59:59.000Z

299

Photoionization electronic spectroscopy of AlAg  

Science Conference Proceedings (OSTI)

AlAg is produced in a supersonic molecular beam by laser vaporization of alloy samples in a pulsed nozzle cluster source. Electronic spectroscopy is studied with resonant two-photon photoionization. In addition to the two electronic excited states previously reported by Clements and Barrow, we have observed ten new states. Vibrational analyses are presented for each of these states, and rotational analyses are given for selected states. The number and characteristics of these excited states are compared to the predictions of recent [ital ab] [ital initio] calculations.

Robbins, D.L.; Yeh, C.S.; Pilgrim, J.S.; Lang, G.L.; Duncan, M.A. (Department of Chemistry, University of Georgia, Athens, Georgia 30602 (United States))

1994-04-01T23:59:59.000Z

300

High-resolution flurescence spectroscopy in immunoanalysis  

SciTech Connect

The work presented in this dissertation combines highly sensitive and selective fluorescence line-narrowing spectroscopy (FLNS) detection with various modes of immunoanalytical techniques. It has been shown that FLNS is capable of directly probing molecules immunocomplexed with antibodies, eliminating analytical ambiguities that may arise from interferences that accompany traditional immunochemical techniques. Moreover, the utilization of highly cross-reactive antibodies for highly specific analyte determination has been demonstrated. Finally, they demonstrate the first example of the spectral resolution of diastereomeric analytes based on their interaction with a cross-reactive antibody.

Grubor, Nenad M.

2005-05-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Light Meson Spectroscopy with the Kloe Experiment  

E-Print Network (OSTI)

We describe the status of the analyses in progress on light meson spectroscopy in the KLOE experiment. We present the analyses of phi decays into f0(980)gamma and a0(980)gamma, the Dalitz plot analysis of the eta to pie+ pie- pie0 decay, the branching ratio measurement of eta to pie0 gamma gamma, the upper limits on Br(eta to 3 gamma) and Br(eta to pie^+ pie^-), the measurement of the ratio Br(phi to eta' gamma)/Br(phi to eta gamma) and phi leptonic width measurements.

The KLOE collaboration; B. Di Micco

2004-10-25T23:59:59.000Z

302

Integral-field spectroscopy of SLACS lenses  

E-Print Network (OSTI)

The combination of two-dimensional kinematics and gravitational lens modelling permits detailed reconstruction of the phase-space structure of early-type galaxies and sets constraints on the dark-matter distribution in their inner regions. We describe a project which combines integral-field spectroscopy from an ESO Large Programme using VIMOS on the VLT with deep HST ACS and NICMOS images to study a sample of 17 early-type lens galaxies at redshifts between 0.1 and 0.3, drawn from the Sloan Lens ACS survey (SLACS).

Oliver Czoske; Matteo Barnabe; Leon Koopmans

2008-11-14T23:59:59.000Z

303

Cavity-locked ring down spectroscopy  

DOE Patents (OSTI)

Distinct locking and sampling light beams are used in a cavity ring-down spectroscopy (CRDS) system to perform multiple ring-down measurements while the laser and ring-down cavity are continuously locked. The sampling and locking light beams have different frequencies, to ensure that the sampling and locking light are decoupled within the cavity. Preferably, the ring-down cavity is ring-shaped, the sampling light is s-polarized, and the locking light is p-polarized. Transmitted sampling light is used for ring-down measurements, while reflected locking light is used for locking in a Pound-Drever scheme.

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

2000-01-01T23:59:59.000Z

304

Precision spectroscopy of the helium atom.  

SciTech Connect

Persistent efforts in both theory and experiment have yielded increasingly precise understanding of the helium atom. Because of its simplicity, the helium atom has long been a testing ground for relativistic and quantum electrodynamic effects in few-body atomic systems theoretically and experimentally. Comparison between theory and experiment of the helium spectroscopy in 1s2p{sup 3}P{sub J} can potentially extract a very precise value of the fine structure constant a. The helium atom can also be used to explore exotic nuclear structures. In this paper, we provide a brief review of the recent advances in precision calculations and measurements of the helium atom.

Hu, S.-M.; Lu, Z.-T.; Yan, Z.-C.; Physics; Univ. of Science and Technology of China; Univ. of Chicago; Univ. of New Brunswick

2009-06-01T23:59:59.000Z

305

Study of clusters using negative ion photodetachment spectroscopy  

SciTech Connect

The weak van der Waals interaction between an open-shell halogen atom and a closed-shell atom or molecule has been investigated using zero electron kinetic energy (ZEKE) spectroscopy. This technique is also applied to study the low-lying electronic states in GaAs and GaAs{sup {minus}}. In addition, the spectroscopy and electron detachment dynamics of several small carbon cluster anions are studied using resonant multiphoton detachment spectroscopy.

Zhao, Yuexing

1995-12-01T23:59:59.000Z

306

Application of QCLs to ns IR Spectroscopy Following Pulse Radiolysis  

NLE Websites -- All DOE Office Websites (Extended Search)

External-Cavity Quantum Cascade Infrared Lasers to Nanosecond Time-Resolved Infrared Spectroscopy of Condensed-Phase Samples Following Pulse Radiolysis David C. Grills, Andrew R....

307

Coherent Anti-Stokes Raman Spectroscopy (CARS) - Available ...  

Search PNNL. PNNL Home; About; Research; Publications; Jobs; News; Contacts; Coherent Anti-Stokes Raman Spectroscopy (CARS) Battelle Number(s): 11982. ...

308

High voltage research (breakdown strengths of gaseous and liquid insulators) and environmental effects of dielectric gases. Semiannual report, April 1, 1979-September 30, 1979. [Health and Safety Research Div. , ORNL  

Science Conference Proceedings (OSTI)

A number of gas mixtures are suggested for industrial-scale testing. Electron attachment rates were measured and unfolded to give attachment cross section functions for CCl/sub 3/F, CCl/sub 2/F/sub 2/, and CClF/sub 3/ each in N/sub 2/, and for CCl/sub 3/F in Ar. Electron attachment rates were measured also for n-C/sub 6/F/sub 14/ in both Ar and N/sub 2/. The effects of molecular structure on energy, cross section, and lifetime of negative ion states of organic molecules were considered. A study was made of the potential role of electron detachment in breakdown. The role of dipolar scattering of electrons in inhibiting breakdown was investigated. The nature of synergisms among constituents of a gas dielectric mixture is discussed. Examples are cited from recent breakdown measurements. Breakdown measurements in plane-plane geometry were made for CF/sub 4/, 1,1,1-CH/sub 3/CF/sub 3/, and CHF/sub 3/. Similar measurements were conducted with binary mixtures containing one of (c-C/sub 4/F/sub 8/, SF/sub 6/) and one of (CF/sub 4/, CH/sub 2/F/sub 2/, 1,1,1-CH/sub 3/CF/sub 3/, CH/sub 2/F/sub 2/). Of special interest in these results were observed synergisms and the effect of dipole moment on the breakdown strengths. The initial fragmentation of 1,1,2-C/sub 2/Cl/sub 3/F/sub 3/ under electron impact was studied. Final decomposition products of sparked SF/sub 6//2-C/sub 4/F/sub 6/ mixtures were identified and quantified. The breakdown products of SF/sub 6/ were studied. Impulse measurements concentrated on c-C/sub 4/F/sub 8//SF/sub 6/ mixtures. Values of V/sub 50/, V/sub NO/, and V/sub 10x/ were obtained and evaluated. In the practical conditions of cylindrical geometry with and without surface roughness, many multicomponent mixtures of the gases SF/sub 6/, c-C/sub 4/F/sub 8/, 2-C/sub 4/F/sub 8/, N/sub 2/, and 1,1,1-CH/sub 3/CF/sub 3/ were tested, at both 1 and 4.4 atmospheres. The electric fields were calculated. In the study of liquid dielectrics n-hexane and perfluoro-n-hexane were tested. 35 figures, 20 tables.

Christophorou, L.G.; James, D.R.; Pai, R.Y.; Mathis, R.A.; Sauers, I.; Frees, L.; Pace, M.O.; Bouldin, D.W.; Chan, C.C.

1980-01-01T23:59:59.000Z

309

Remote Adjustable focus Raman Spectroscopy Probe  

DOE Patents (OSTI)

A remote adjustable focus Raman spectroscopy probe allows for analyzing Raman scattered light from a point of interest external to the probe. An environmental barrier including at least one window separates the probe from the point of interest. An optical tube is disposed adjacent to the environmental barrier and includes along working length compound lens objective next to the window. A beam splitter and a mirror are at the other end. A mechanical means is used to translate the probe body in the X, Y, and Z directions resulting in a variable focus optical apparatus. Laser light is reflected by the beam splitter and directed toward the compound lens objective, then through the window and focused on the point of interest. Raman scattered light is then collected by the compound lens objective and directed through the beam splitter to a mirror. A device for analyzing the light, such as a monochrometer, is coupled to the mirror.

Schmucker, John E.; Blasi, Raymond J.; Archer, William B.

1998-07-28T23:59:59.000Z

310

Quantitative Spectroscopy of BA-type Supergiants  

E-Print Network (OSTI)

Luminous BA-SGs allow topics ranging from NLTE physics and the evolution of massive stars to the chemical evolution of galaxies and cosmology to be addressed. A hybrid NLTE technique for the quantitative spectroscopy of BA-SGs is discussed. Thorough tests and first applications of the spectrum synthesis method are presented for four bright Galactic objects. Stellar parameters are derived from spectroscopic indicators. The internal accuracy of the method allows the 1sigma-uncertainties to be reduced to reduce random errors and remove systematic trends in the analysis. Inappropriate LTE analyses tend to systematically underestimate iron group abundances and overestimate the light and alpha-process element abundances by up to factors of 2-3 on the mean. Contrary to common assumptions, significant NLTE abundance correction...

Przybilla, N; Becker, S R; Kudritzki, R P

2005-01-01T23:59:59.000Z

311

New developments in IR surface vibrational spectroscopy  

DOE Green Energy (OSTI)

Low frequency dynamics at surfaces, particularly in the region of the adsorbate-substrate vibrational modes is of fundamental importance in areas as varied as sliding friction, catalysis, corrosion and epitaxial growth. This paper reviews the new developments in low frequency Infrared Reflection Absorption Spectroscopy using synchrotron radiation as the source. Absolute changes induced in the far infrared for several adsorbate systems on Cu, including CO and H, are dominated by broadband reflectance changes and dipole forbidden vibrational modes which in some cases are an order of magnitude stronger than the dipole allowed modes. The experimental data can be explained by a theory developed by Persson, in which the dielectric response of the substrate is seen as playing a crucial role in the dynamics. In particular the relationships between the wavelength of the light, the penetration depth and the electron mean-free path, are critical.

Hirschmugl, C.J.; Lamont, C.L.A.; Williams, G.P. [Brookhaven National Lab., Upton, NY (United States). National Synchrotron Light Source

1995-12-31T23:59:59.000Z

312

Delta, iota and other meson spectroscopies  

Science Conference Proceedings (OSTI)

This talk is given from the point of view of an experimentalist. Meson spectroscopy in the 1 to 3 GeV region is interesting because experiments exploring this region, in particular radiative psi decay, have found a rich structure of resonances too complicated to unravel with any one experiment, and not easily interpreted with any one theoretical model. None of the theoretical calculations predicting all kinds of interesting and exotic objects in this region is very convincing or reliable. Additional input from anti pp annihilation can be very useful in helping to find the answers to the following open questions: what exactly is this spectrum, what are the masses and quantum numbers of the resonances, as determined from analysis of data without theoretical prejudices; how is this spectrum described by QCD, is there evidence for new kinds of states like glue-balls, hybrids, axions, Higgses or multiquark exotics, and is there any evidence for new physics beyond QCD. 20 refs.

Lipkin, H.J.

1986-05-01T23:59:59.000Z

313

Pu electronic structure and photoelectron spectroscopy  

Science Conference Proceedings (OSTI)

The electronic structure of PuCoGa{sub 5}, Pu metal, and PuO{sub 2} is explored using photoelectron spectroscopy. Ground state electronic properties are inferred from temperature dependent photoemission near the Fermi energy for Pu metal. Angle-resolved photoemission details the energy vs. crystaJ momentum landscape near the Fermi energy for PuCoGa{sub 5} which shows significant dispersion in the quasiparticle peak near the Fermi energy. For the Mott insulators AnO{sub 2}(An = U, Pu) the photoemission results are compared against hybrid functional calculations and the model prediction of a cross over from ionic to covalent bonding is found to be reasonable.

Joyce, John J [Los Alamos National Laboratory; Durakiewicz, Tomasz [Los Alamos National Laboratory; Graham, Kevin S [Los Alamos National Laboratory; Bauer, Eric D [Los Alamos National Laboratory; Moore, David P [Los Alamos National Laboratory; Mitchell, Jeremy N [Los Alamos National Laboratory; Kennison, John A [Los Alamos National Laboratory; Martin, Richard L [Los Alamos National Laboratory; Roy, Lindsay E [Los Alamos National Laboratory; Scuseria, G. E. [RICE UNIV

2010-01-01T23:59:59.000Z

314

Remote adjustable focus Raman spectroscopy probe  

DOE Patents (OSTI)

A remote adjustable focus Raman spectroscopy probe allows for analyzing Raman scattered light from a point of interest external probe. An environmental barrier including at least one window separates the probe from the point of interest. An optical tube is disposed adjacent to the environmental barrier and includes a long working length compound lens objective next to the window. A beam splitter and a mirror are at the other end. A mechanical means is used to translated the prove body in the X, Y, and Z directions resulting in a variable focus optical apparatus. Laser light is reflected by the beam splitter and directed toward the compound lens objective, then through the window and focused on the point of interest. Raman scattered light is then collected by the compound lens objective and directed through the beam splitter to a mirror. A device for analyzing the light, such as a monochrometer, is coupled to the mirror.

Schmucker, John E. (Hurt, VA); Blasi, Raymond J. (Harrison City, PA); Archer, William B. (Bethel Park, PA)

1999-01-01T23:59:59.000Z

315

Anion photoelectron spectroscopy of radicals and clusters  

SciTech Connect

Anion photoelectron spectroscopy is used to study free radicals and clusters. The low-lying {sup 2}{Sigma} and {sup 2}{Pi} states of C{sub 2n}H (n = 1--4) have been studied. The anion photoelectron spectra yielded electron affinities, term values, and vibrational frequencies for these combustion and astrophysically relevant species. Photoelectron angular distributions allowed the author to correctly assign the electronic symmetry of the ground and first excited states and to assess the degree of vibronic coupling in C{sub 2}H and C{sub 4}H. Other radicals studied include NCN and I{sub 3}. The author was able to observe the low-lying singlet and triplet states of NCN for the first time. Measurement of the electron affinity of I{sub 3} revealed that it has a bound ground state and attachment of an argon atom to this moiety enabled him to resolve the symmetric stretching progression.

Travis, Taylor R.

1999-12-16T23:59:59.000Z

316

Spectroscopy, Kinetics, and Dynamics of Combustion Radicals  

SciTech Connect

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.

Nesbitt, David J. [Research/Professor

2013-08-06T23:59:59.000Z

317

Core Level Spectroscopies Surface Science and X-Ray Spectroscopy Group  

NLE Websites -- All DOE Office Websites (Extended Search)

Core Level Spectroscopy Creation and Decay of Core Holes Spectroscopic Techniques X-ray Photoelectron (XPS) X-ray Absorption (XAS) X-ray Emission (XES) Auger Electron (AES) Core holes are created by the ionization of a core electron in XPS and by excitation in XAS . The XPS and XAS final states are highly unstable and the core hole decays by non-radiant Auger relaxation (AES) or by radiant x-ray emission processes (XES). XPS and AES probe the unoccupied electronic stru cture, while XAS projects the unoccupied valence states of the system onto a particular atom. A brief description of the each of the different spectroscopies illustrated by schematic pictures of the creation and decay with data measured for N2 adsorbed on Ni(100) can be found by scrolling

318

Guanine tautomerism revealed by UVUV and IRUV hole burning spectroscopy  

E-Print Network (OSTI)

Guanine tautomerism revealed by UV­UV and IR­UV hole burning spectroscopy E. Nir Department spectroscopy. 1-methylguanine, in which the Keto­Enol tautomerism is blocked, shows hole burning spectra from hole burning SHB by using two counter- propagating dye laser pulses with a delay of about 150 ns

de Vries, Mattanjah S.

319

Probing brain oxygenation with near infrared spectroscopy  

E-Print Network (OSTI)

The fundamentals of near infrared spectroscopy (NIRS) are reviewed. This technique allows to measure the oxygenation of the brain tissue. The particular problems involved in detecting regional brain oxygenation (rSO2) are discussed. The dominant chromophore (light absorber) in tissue is water. Only in the NIR light region of 650-1000 nm, the overall absorption is sufficiently low, and the NIR light can be detected across a thick layer of tissues, among them the skin, the scull and the brain. In this region, there are many absorbing light chromophores, but only three are important as far as the oxygenation is concerned. They are the hemoglobin (HbO2), the deoxy-hemoglobin (Hb) and cytochrome oxidase (CtOx). In the last 20 years there was an enormous growth in the instrumentation and applications of NIRS. . The devices that were used in our experiments were : Somanetics's INVOS Brain Oximeter (IBO) and Toomim's HEG spectrophotometer. The performances of both devices were compared including their merits and draw...

Gersten, Alexander; Raz, Amir; Fried, Robert

2011-01-01T23:59:59.000Z

320

On spectroscopy for a whole Abelian model  

Science Conference Proceedings (OSTI)

Postulated on the whole meaning a whole abelian gauge symmetry is being introduced. Various physical areas as complexity, statistical mechanics, quantum mechanics are partially supporting this approach where the whole is at origin. However, the reductionist crisis given by quark confinement definitely sustains this insight. It says that fundamental parts can not be seen isolatedely. Consequently, there is an experimental situation where the parts should be substituted by something more. This makes us to look for writing the wholeness principle under gauge theory. For this, one reinterprets the gauge parameter where instead of compensating fields it is organizing a systemic gauge symmetry. Now, it introduces a fields set {l_brace}A{sub {mu}I}{r_brace} rotating under a common gauge symmetry. Thus, given a fields collection {l_brace}A{sub {mu}I}{r_brace} as origin, the effort at this work is to investigate on its spectroscopy. Analyze for the abelian case the correspondent involved quanta. Understand that for a whole model diversity replaces elementarity. Derive the associated quantum numbers as spin, mass, charge, discrete symmetries in terms of such systemic symmetry. Observe how the particles diversity is manifested in terms of wholeness.

Chauca, J.; Doria, R. [CBPF, Rio de Janeiro (Brazil); Aprendanet, Petropolis, 25600 (Brazil)

2012-09-24T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

EXPERIMENTS ON SELECTIVE EXCITATION OF MULTIPLE-QUANTUM TRANSITIONS IN NMR SPECTROSCOPY  

E-Print Network (OSTI)

M. Mehring, High Resolution NMR Spectroscopy in Solids (sequences for producing quantum NMR spectra. multiple~ InMULTIPLE-QUANTUM TRANSITIONS IN NMR SPECTROSCOPY W.S. Warren

Warren, W.S.

2013-01-01T23:59:59.000Z

322

Bimolecular reaction dynamics from photoelectron spectroscopy of negative ions  

DOE Green Energy (OSTI)

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

Bradforth, S.E.

1992-11-01T23:59:59.000Z

323

Magnetic spectroscopy and microscopy of functional materials  

SciTech Connect

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).

Jenkins, C.A.

2011-01-28T23:59:59.000Z

324

Broadband Dielectric Spectroscopy on Human Blood  

E-Print Network (OSTI)

Dielectric spectra of human blood reveal a rich variety of dynamic processes. Achieving a better characterization and understanding of these processes not only is of academic interest but also of high relevance for medical applications as, e.g., the determination of absorption rates of electromagnetic radiation by the human body. The dielectric properties of human blood are studied using broadband dielectric spectroscopy, systematically investigating the dependence on temperature and hematocrit value. By covering a frequency range from 1 Hz to 40 GHz, information on all the typical dispersion regions of biological matter is obtained. We find no evidence for a low-frequency relaxation (alpha-relaxation) caused, e.g., by counterion diffusion effects as reported for some types of biological matter. The analysis of a strong Maxwell-Wagner relaxation arising from the polarization of the cell membranes in the 1-100 MHz region (beta-relaxation) allows for the test of model predictions and the determination of various intrinsic cell properties. In the microwave region beyond 1 GHz, the reorientational motion of water molecules in the blood plasma leads to another relaxation feature (gamma-relaxation). Between beta- and gamma-relaxation, significant dispersion is observed, which, however, can be explained by a superposition of these relaxation processes and is not due to an additional delta-relaxation often found in biological matter. Our measurements provide dielectric data on human blood of so far unsurpassed precision for a broad parameter range. All data are provided in electronic form to serve as basis for the calculation of the absorption rate of electromagnetic radiation and other medical purposes. Moreover, by investigating an exceptionally broad frequency range, valuable new information on the dynamic processes in blood is obtained.

M. Wolf; R. Gulich; P. Lunkenheimer; A. Loidl

2011-05-25T23:59:59.000Z

325

Nonlinear optical spectroscopy of diamond surfaces  

DOE Green Energy (OSTI)

Second harmonic generation (SHG) and infrared-visible sum frequency generation (SFG) spectroscopies have been shown to be powerful and versatile for studying surfaces with submonolayer sensitivity. They have been used in this work to study bare diamond surfaces and molecular adsorption on them. In particular, infrared-visible SFG as a surface vibrational spectroscopic technique has been employed to identify and monitor in-situ surface bonds and species on the diamond (111) surface. The CH stretch spectra allow us to investigate hydrogen adsorption, desorption, abstraction, and the nature of the hydrogen termination. The C(111) surface dosed with atomic hydrogen was found to be in a monohydride configuration with the hydrogen atoms situated at top-sites. The ratio of the abstraction rate to the adsorption rate was appreciable during atomic hydrogen dosing. Kinetic parameters for thermal desorption of H on C(111) were determined showing a near first-order kinetics. For the fully H-terminated (111) surface, a large (110 cm{sup {minus}1}) anharmonicity and {approximately}19 psec lifetime were measured for the first-excited CH stretch mode. The bare reconstructed C(111)-(2 {times} l) surface showed the presence of CC stretch modes which were consistent with the Pandey {pi}-bonded chain structure. When exposed to the methyl radical, the SFG spectra of the C(111) surface showed features suggesting the presence of adsorbed methyl species. After heating to sufficiently high temperatures, they were converted into the monohydride species. Preliminary results on the hydrogen-terminated diamond (100) surface are also presented.

Chin, R.P.

1995-04-01T23:59:59.000Z

326

Neutrino Spectroscopy with Atoms and Molecules  

E-Print Network (OSTI)

We give a comprehensive account of our proposed experimental method of using atoms or molecules in order to measure parameters of neutrinos still undetermined; the absolute mass scale, the mass hierarchy pattern (normal or inverted), the neutrino mass type (Majorana or Dirac), and the CP violating phases including Majorana phases. There are advantages of atomic targets, due to the closeness of available atomic energies to anticipated neutrino masses, over nuclear target experiments. Disadvantage of using atomic targets, the smallness of rates, is overcome by the macro-coherent amplification mechanism. The atomic or molecular process we use is a cooperative deexcitation of a collective body of atoms in a metastable level |e> emitting a neutrino pair and a photon; |e> -> |g> + gamma + nu_i nu_j where nu_i's are neutrino mass eigenstates. The macro-coherence is developed by trigger laser irradiation. We discuss aspects of the macro-coherence development by setting up the master equation for the target quantum state and propagating electric field. With a choice of heavy target atom or molecule such as Xe or I_2 that has a large M1 x E1 matrix element between |e> and |g>, we show that one can determine three neutrino masses along with the mass hierarchy pattern by measuring the photon spectral shape. If one uses a target of available energy of a fraction of 1 eV, Majorana CP phases may be determined. Our master equation, when applied to E1 x E1 transition such as pH_2 vibrational transition Xv=1 -> 0, can describe explosive PSR events in which most of the energy stored in |e> is released within a few nanoseconds. The present paper is intended to be self-contained explaining some details related theoretical works in the past, and further reports new simulations and our ongoing experimental efforts of the project to realize the neutrino mass spectroscopy using atoms/molecules.

Atsushi Fukumi; Susumu Kuma; Yuki Miyamoto; Kyo Nakajima; Itsuo Nakano; Hajime Nanjo; Chiaki Ohae; Noboru Sasao; Minoru Tanaka; Takashi Taniguchi; Satoshi Uetake; Tomonari Wakabayashi; Takuya Yamaguchi; Akihiro Yoshimi; Motohiko Yoshimura

2012-11-21T23:59:59.000Z

327

Microsoft PowerPoint - SpectroscopyTechniques_XANES  

NLE Websites -- All DOE Office Websites (Extended Search)

Near Edge Spectroscopy (XANES) Near Edge Spectroscopy (XANES) XANES: XANES: * Element specific * Highly sensitive to bond angles, bond lengths, and the presence of adsorbates NEXAFS (Near Edge X-ray Absorption Fine Structure): * Synonymous with XANES but soft x-ray spectroscopy (< 1keV) * Fine structure within about 30 eV of the absorption edge EXAFS XANES / XRD C bi i S EXAFS-XANES / XRD Combination Spectroscopy * XAFS-XANES and XRD techniques give complementary information about the structure of materials. * XRD is effective in materials with medium- to long-range A typical XANES Spectrum XRD is effective in materials with medium to long range order while XAFS provides short-range information. *The simultaneous collection of the XRD and XAFS- XANES data in situ will allow

328

Raman Spectroscopy of High Thermal Conductivity AlN Ceramics ...  

Science Conference Proceedings (OSTI)

Thermal conductivity of AlN ceramics was measured by laser flash method. Raman spectroscopy was used to characterize oxygen related defects of AlN ... Transport in Co-Based Materials for Fuel Cells and Oxygen Separation Membranes.

329

Microwave quantum logic spectroscopy and control of molecular ions  

E-Print Network (OSTI)

A general method for rotational microwave spectroscopy and control of polar molecular ions via direct microwave addressing is considered. Our method makes use of spatially varying ac Stark shifts, induced by far off-resonant, ...

Drewsen, M

330

Radio-frequency spectroscopy of ultracold atomic Fermi gases  

E-Print Network (OSTI)

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 ...

Schirotzek, Andre

2010-01-01T23:59:59.000Z

331

Precision spectroscopy by photon-recoil signal amplification  

E-Print Network (OSTI)

Precision spectroscopy of atomic and molecular ions offers a window to new physics, but is typically limited to species with a cycling transition for laser cooling and detection. Quantum logic spectroscopy has overcome this limitation for species with long-lived excited states. Here, we extend quantum logic spectroscopy to fast, dipole-allowed transitions and apply it to perform an absolute frequency measurement. We detect the absorption of photons by the spectroscopically investigated ion through the photon recoil imparted on a co-trapped ion of a different species, on which we can perform efficient quantum logic detection techniques. This amplifies the recoil signal from a few absorbed photons to thousands of fluorescence photons. We resolve the line center of a dipole-allowed transition in 40Ca+ to 1/300 of its observed linewidth, rendering this measurement one of the most accurate of a broad transition. The simplicity and versatility of this approach enables spectroscopy of many previously inaccessible species.

Yong Wan; Florian Gebert; Jannes B. Wübbena; Nils Scharnhorst; Sana Amairi; Ian D. Leroux; Börge Hemmerling; Niels Lörch; Klemens Hammerer; Piet O. Schmidt

2013-09-26T23:59:59.000Z

332

Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy  

NLE Websites -- All DOE Office Websites (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...

333

Fourier Transform Infrared Spectroscopy for Process Monitoring and Control  

E-Print Network (OSTI)

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.

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

1994-04-01T23:59:59.000Z

334

FRONTIER SYNCHROTRON INFRARED SPECTROSCOPY BEAMLINE UNDER EXTREME CONDITIONS (FIS)  

NLE Websites -- All DOE Office Websites (Extended Search)

FRONTIER SYNCHROTRON INFRARED SPECTROSCOPY FRONTIER SYNCHROTRON INFRARED SPECTROSCOPY BEAMLINE UNDER EXTREME CONDITIONS (FIS) Proposal Team: L. Carr 1 , D. Dolan 2 , R. Hemley 3 , S. Jacobson 4 , S. Karato 5 , Z. Liu 3 , W. Panero 6 , M. Pravica 7 , and T. Zhou 8 1 Brookhaven National Laboratory, 2 Sandia National Laboratories, 3 Carnegie Institution of Washington, 4 Northwestern University, 5 Yale University, 6 Ohio State University, 7 University of Nevada, 8 New Jersey Institute of Technology TECHNIQUES AND CAPABILITIES APPLICATIONS SPECIFIC PROJECTS / ADDITIONAL INFORMATION * TECHNIQUE(S): Fourier transform infrared spectroscopy; Raman and visible spectroscopy; Diamond anvil cell techniques for static high pressure; Gas-gun launchers for dynamic compression; Cryogenic techniques combined with DACs;

335

Breakdown of NISS Conference Proceedings  

Science Conference Proceedings (OSTI)

... Encryption (SAFE) Act (.pdf) (98,156 bytes / 95 KB) Catherine Miller Horiuchi, Sacramento Municipal Utility District, University of Southern California. ...

336

Virtual workplaces : when metaphors breakdown  

E-Print Network (OSTI)

Our model of work is shaped by the places we choose to work and the tools we choose to work with. As we introduce new technologies and build new environments our model is changing. Today's virtual workplaces are grounded ...

Gallemore, Thomas W. I. (Thomas Wilson Ira), 1969-

1998-01-01T23:59:59.000Z

337

Barotropic Aspects of ITCZ Breakdown  

Science Conference Proceedings (OSTI)

In satellite images the ITCZ (intertropical convergence zone) is sometimes observed to undulate and break down into a series of tropical disturbances. Tropical cyclones may later develop within these disturbances and move into higher latitudes ...

Rosana Nieto Ferreira; Wayne H. Schubert

1997-01-01T23:59:59.000Z

338

Breakdown of NISS Conference Proceedings  

Science Conference Proceedings (OSTI)

... Kimberly Kaplan, Computer Sciences Corporation James Reynolds, Cygnacom Solutions, Incorporated Edward McLaughlin, National Software ...

339

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

SciTech Connect

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.

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)

2012-03-19T23:59:59.000Z

340

INFRARED ABSORPTION SPECTROSCOPY AND CHEMICAL KINETICS OF FREE RADICALS  

NLE Websites -- All DOE Office Websites (Extended Search)

mNAL PERFORMANCE REPORT mNAL PERFORMANCE REPORT for INFRARED ABSORPTION SPECTROSCOPY AND CHEMICAL KINETICS OF FREE RADICALS DE-FG05-85ER13439 1-AUG-1985 to 31-JUL-1994 Robert F. Curl and Graham P. Glass Principal Investigators Introduction This research was directed at the detection, monitoring, and study (by infrared absorption spectroscopy) of the chemical kinetic behavior of small free radical species thought to be important intermediates in combustion. The work typically progressed from the detection and analysis of the infrared spectrum of combustion radical to the utilization of the infrared spectrum thus obtained in the investigation of chemical kinetics of the radical species. The methodology employed was infrared kinetic spectroscopy. In this technique the radical is produced by UV flash photolysis using an excimer laser and then

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341

Photon Sciences | Beamlines | SRX: Submicron Resolution X-ray Spectroscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

SRX: Submicron Resolution X-ray Spectroscopy SRX: Submicron Resolution X-ray Spectroscopy Poster | Fact Sheet | Preliminary Design Report Scientific Scope Scientific communities such as environmental sciences, life sciences, and material sciences have identified the need to develop analytical resources to advance the understanding of complex natural and engineered systems that are heterogeneous on the micron to nanometer scale. These needs for high intensity x-ray nanoprobes resulted in the commitment of the NSLS-II Project to build the Submicron Resolution X-ray (SRX) Spectroscopy beamline showing a unique combination of high spectral resolution over a very broad energy range and very high beam intensity in a sub-micrometer spot. NSLS-II will provide one of the best sources in the world for such an instrument.

342

2010 GRC VIBRATIONAL SPECTROSCOPY AUGUST 1 - AUGUST 6, 2010  

SciTech Connect

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.

Brooks Pate

2010-08-06T23:59:59.000Z

343

Charm and Charmonium Spectroscopy at B-factories  

SciTech Connect

Since a few years, charm and charmonium spectroscopy has revived, both from experimental and theoretical point of views. Many new states have been discovered triggering numerous theoretical publications. The B-factories with their large enriched charm sample have played a leading role on the experimental side with the observation and study of most of the new states. Other experiments such as CLEO and CDF have also contributed. Classical hadron spectroscopy predicted some of these new states, but not all of them. Therefore a lot of effort have been spent in order to understand the nature of the later. We are summarizing here the most recent and important results in hadron spectroscopy, including strange-charm mesons, charm baryons and charmonium and charmonium-like states.

Grenier, Philippe; /SLAC /Ecole Normale Superieure, CNRS

2007-05-18T23:59:59.000Z

344

Optical and plasmonic spectroscopy with cantilever shaped materials  

NLE Websites -- All DOE Office Websites (Extended Search)

plasmonic spectroscopy with cantilever shaped materials plasmonic spectroscopy with cantilever shaped materials This article has been downloaded from IOPscience. Please scroll down to see the full text article. 2011 J. Phys. D: Appl. Phys. 44 445102 (http://iopscience.iop.org/0022-3727/44/44/445102) Download details: IP Address: 128.219.49.13 The article was downloaded on 28/12/2012 at 18:01 Please note that terms and conditions apply. View the table of contents for this issue, or go to the journal homepage for more Home Search Collections Journals About Contact us My IOPscience IOP PUBLISHING JOURNAL OF PHYSICS D: APPLIED PHYSICS J. Phys. D: Appl. Phys. 44 (2011) 445102 (9pp) doi:10.1088/0022-3727/44/44/445102 Optical and plasmonic spectroscopy with cantilever shaped materials L Tetard 1 , A Passian 1,2 , R H Farahi 1 , B H Davison 1 , A L Lereu 3 and T Thundat

345

2-2 Environmental Spectroscopy & Biogeochemistry Facility  

NLE Websites -- All DOE Office Websites (Extended Search)

ES&B Overview ES&B Overview Environmental Spectroscopy & Biogeochemistry Facility The Environmental Spectroscopy & Biogeochemistry (ES&B) Facility focuses on environ- mental molecular science and application of the fundamental concepts of physical chemistry to the study of chemical reactions in heterogeneous natural materials, with an emphasis on soil and subsurface systems. The ES&B Facility staff, along with other Pacific Northwest National Laboratory (PNNL) staff, form a multidisciplinary organization with expertise in chemistry, mineral physics, geochemistry, soil chemistry, microbiology, hydrology, and environmental engineering. Capabilities are available for materials characterization, aqueous-phase and solid-phase speciation and reaction/kinetic measurements, analytical environmental chemistry, molecular

346

Photocapacitance spectroscopy of surface states on indium phosphide photoelectrodes  

SciTech Connect

Indium phosphide photoelectrodes have been studied in situ using electrochemical photocapacitance spectroscopy. The observed photocapacitance spectra were a strong function of electrode surface conditions. The photoionization energies of the chemically induced surface states correlated well with previously reported values determined by surface photovoltage spectroscopy. The chemical treatment of the InP electrode surface with Co and Pt reduced the concentration of deep level interface states near the valence band and introduced a new state at E/sub v/+1.2 eV.

Goodman, C.E.; Wessels, B.W.; Ang, P.G.P.

1984-08-15T23:59:59.000Z

347

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

SciTech Connect

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

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

2008-01-15T23:59:59.000Z

348

Excited State Spectroscopy in the Lattice Gross-Neveu Model  

E-Print Network (OSTI)

We present preliminary results of an excited state spectroscopy calculation in the 2-d lattice Gross-Neveu model. We address the construction of suitable interpolators for the variational method and their overlap with excitations. We comment on the role of the eigenvectors as a tool for matching scattering states on lattices with different volumes.

Julia Danzer; Christof Gattringer

2007-10-09T23:59:59.000Z

349

Development of Raman Spectroscopy for a Steam Generator Heated Crevice  

Science Conference Proceedings (OSTI)

The crevice formed by the tube / tube support plate (tube/TSP) intersection in a pressurized water reactor (PWR) steam generator (SG) is a concentration site for nonvolatile impurities from steam generator water (referred to as hideout). This report describes development of a Raman spectroscopy device to investigate this chemical concentration process in situ in a simulated heated crevice.

2003-11-11T23:59:59.000Z

350

Positron annihilation spectroscopy study of materials for reactor vessels  

Science Conference Proceedings (OSTI)

Steels used in the nuclear industry have been experimentally studied by positron annihilation spectroscopy. Analysis of the experimental results and their comparison with the existing data make it possible to reveal vacancy defects, in particular, those caused by neutron radiation, and to determine their size.

Grafutin, V. I.; Prokop'ev, E. P. [Institute for Theoretical and Experimental Physics (Russian Federation); Krsjak, V.; Burcl, R.; Haehner, P.; Zeman, A. [Joint Research Centre of the European Commission, Institute for Energy (Netherlands); Ilyukhina, O. V., E-mail: ilyukhina@itep.ru [Institute for Theoretical and Experimental Physics (Russian Federation); Erak, D. [Russian Research Centre Kurchatov Institute (Russian Federation); Mogilevskyi, M. A.; Myasischeva, G. G.; Funtikov, Yu. V. [Institute for Theoretical and Experimental Physics (Russian Federation)

2011-02-15T23:59:59.000Z

351

Single atom identification by energy dispersive x-ray spectroscopy  

SciTech Connect

Using aberration-corrected scanning transmission electron microscope and energy dispersive x-ray spectroscopy, single, isolated impurity atoms of silicon and platinum in monolayer and multilayer graphene are identified. Simultaneously acquired electron energy loss spectra confirm the elemental identification. Contamination difficulties are overcome by employing near-UHV sample conditions. Signal intensities agree within a factor of two with standardless estimates.

Lovejoy, T. C.; Dellby, N.; Krivanek, O. L. [Nion, 1102 8th St., Kirkland, Washington 98033 (United States); Ramasse, Q. M. [SuperSTEM Laboratory, STFC Daresbury, Keckwick Lane, Daresbury WA4 4AD (United Kingdom); Falke, M.; Kaeppel, A.; Terborg, R. [Bruker Nano GmbH, Schwarzschildstr. 12, 12489 Berlin (Germany); Zan, R. [School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom)

2012-04-09T23:59:59.000Z

352

Novel gold cantilever for nano-Raman spectroscopy of graphene  

Science Conference Proceedings (OSTI)

This paper presents the simultaneous topographical and tip-enhanced Raman imaging of single layer and multilayer graphene flakes. The probe tips suitable for tapping mode atomic force microscopy (AFM) and tip-enhanced Raman spectroscopy have been fabricated ... Keywords: Atomic force microscopy, Graphene, Nano-Raman, Tip-enhanced

Valentinas Snitka; Raul D. Rodrigues; Vitas Lendraitis

2011-08-01T23:59:59.000Z

353

Development of multimodal spectroscopy for the detection of vulnerable atherosclerotic plaques  

E-Print Network (OSTI)

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 ...

Š?epanovi?, Obrad R., 1980-

2008-01-01T23:59:59.000Z

354

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

E-Print Network (OSTI)

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

Jackson, Jennifer M.

355

Standoff Detection of Chemicals Using Rydberg Fingerprint Spectroscopy and Microwave Rayleigh Scattering  

The invention relates to a method for standoff trace chemical sensing. The basis forthe technique is Rydberg Fingerprint Spectroscopy followed by microwave-baseddetection.In Rydberg Fingerprint Spectroscopy, target molecules are first excited to ...

356

High-resolution NMR spectroscopy of biological tissues using projected Magic Angle Spinning  

E-Print Network (OSTI)

High-resolution NMR spectroscopy of biological tissues using486-5744 pines@berkeley.edu NMR spectroscopy of biologicalAbstract: High-resolution NMR spectra of materials subject

Martin, Rachel W.; Jachmann, Rebecca C.; Sakellariou, Dimitris; Nielsen, Ulla Gro; Pines, Alexander

2005-01-01T23:59:59.000Z

357

Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print 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 by applying a gate voltage. The charge carriers in graphene can travel ballistically over great distances (~1 micron) without scattering. These unusual electronic properties make graphene a promising candidate for future nanoelectronics. Using infrared spectromicroscopy at ALS Beamline 1.4, a group of researchers from the University of California at San Diego, Columbia University, and the ALS has succeeded in probing the dynamical properties of the charge carriers in graphene with an accuracy never before achieved. Their results have uncovered signatures of many-body interactions in graphene and have demonstrated the potential of graphene for novel applications in optoelectronics.

358

Microsoft PowerPoint - SpectroscopyTechniques_EXAFS  

NLE Websites -- All DOE Office Websites (Extended Search)

X-ray Absorption Fine Structure Spectroscopy (EXAFS) X-ray Absorption Fine Structure Spectroscopy (EXAFS) * Provides details on how x rays are absorbed by an atom at energies near X18A,B,X19A * Provides details on how x-rays are absorbed by an atom at energies near and above the core-level binding energies of that atom * Gives the modulation of an atom's x-ray absorption probability due to the chemical and physical state of the atom * Especially sensitive to the formal oxidation state, coordination chemistry, and the distances, coordination numbers, and species of the atoms immediately surrounding the selected element * Provides a practical, and relatively simple, way to determine the chemical state and local atomic structure for a selected atomic species

359

Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

Dirac Charge Dynamcs in Graphene 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 of carbon atoms arranged in a honeycomb lattice-has very high conductivity that can be tuned by applying a gate voltage. The charge carriers in graphene can travel ballistically over great distances (~1 micron) without scattering. These unusual electronic properties make graphene a promising candidate for future nanoelectronics. Using infrared spectromicroscopy at ALS Beamline 1.4, a group of researchers from the University of California at San Diego, Columbia University, and the ALS has succeeded in probing the dynamical properties of the charge carriers in graphene with an accuracy never before achieved. Their results have uncovered signatures of many-body interactions in graphene and have demonstrated the potential of graphene for novel applications in optoelectronics.

360

Photoelectron Spectroscopy under Ambient Pressure and Temperature Conditions  

SciTech Connect

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.

Ogletree, D. Frank; Bluhm, Hendrik; Hebenstreit, Eleonore B.; Salmeron, Miquel

2009-02-27T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Time-frequency resolved ultrafast spectroscopy techniques using wavelet analysis  

E-Print Network (OSTI)

New experimental techniques based on non-linear ultrafast spectroscopies have been developed over the last few years, and have been demonstrated to provide powerful probes of quantum dynamics in different types of molecular aggregates, including both natural and artificial light harvesting complexes. Fourier transform-based spectroscopies have been particularly successful, yet 'complete' spectral information normally necessitates the loss of all information on the temporal sequence of events in a signal. This information though is particularly important in transient or multi-stage processes, in which the spectral decomposition of the data evolves in time. By going through several examples of ultrafast quantum dynamics, we demonstrate that the use of wavelets provide an efficient and accurate way to simultaneously acquire both temporal and frequency information about a signal, and argue that this greatly aids the elucidation and interpretation of physical process responsible for non-stationary spectroscopic features, such as those encountered in coherent excitonic energy transport.

Javier Prior; Enrique Castro; Alex W. Chin; Javier Almeida; Susana F. Huelga; Martin B. Plenio

2013-08-21T23:59:59.000Z

362

Exploitation of resonance Raman spectroscopy as a remote chemical sensor  

SciTech Connect

We have discussed recent experimental results using a resonance-Raman-based LIDAR system as a remote chemical sensor. This spectroscopy has the fundamental advantage that it is based on optical fingerprints that are insensitive to environmental perturbations. By taking advantage of resonance enhancement, which 6 orders-of-magnitude, can be as large as 4 to an increased sensing range for a given chemical concentration or lower detection limit for a given stand-off distance can be realized. The success discussed above can in part be traced back to the use of new state-of-the-art technologies which, only recently, have allowed the phenomenon of resonance-enhanced Raman spectroscopy to be fully exploited as a remote chemical sensor platform. Since many chemicals have electronic transitions in the UV/IS, it is expected that many will have pronounced resonance enhancements.

Sedlacek, A.J.; Chen, C.L.

1995-08-01T23:59:59.000Z

363

Photodissociation dynamics and spectroscopy of free radical combustion intermediates  

Science Conference Proceedings (OSTI)

The photodissociation spectroscopy and dynamics of free radicals is studied by the technique of fast beam photofragment translational spectroscopy. Photodetachment of internally cold, mass-selected negative ions produces a clean source of radicals, which are subsequently dissociated and detected. The photofragment yield as a function of photon energy is obtained, mapping out the dissociative and predissociative electronic states of the radical. In addition, the photodissociation dynamics, product branching ratios, and bond energies are probed at fixed photon energies by measuring the translational energy, P(E{sub T}), and angular distribution of the recoiling fragments using a time- and position-sensitive detector. Ab initio calculations are combined with dynamical and statistical models to interpret the observed data. The photodissociation of three prototypical hydrocarbon combustion intermediates forms the core of this work.

Osborn, D.L.

1996-12-01T23:59:59.000Z

364

Impedance spectroscopy of electrodes modified by Langmuir-Blodgett films  

SciTech Connect

The techniques of a.c. impedance spectroscopy and FTIR spectroscopy are used to investigate the properties of Langmuir-Blodgett (LB) films deposited respectively on ITO (Indium Tin Oxyde) coated glass electrode, and on Calcium Fluoride plates. 22-tricosenoic acid is transferred from a subphase containing an electrolyte and a redox system (Fe(CN){sup 3{minus}/4{minus}}). The IR spectra show selective insertion of the Fe(CN){sup 4{minus}} ion in the film. Measurements of the complex impedance of 22-tricosenoic acid are then presented and discussed as a function of the number of deposited layers. An equivalent electrical circuit is proposed which takes into account the defects of the film. {copyright} {ital 1996 American Institute of Physics.}

Vignau, L.; Morand, J.P. [Laboratoire de Photophysique-Photochimie Moleculaire (France); Frimigacci, M. [Ecole Nationale Superieure de Chimie et de Physique de Bordeaux, Universite de Bordeaux I, 33405 Talence Cedex (France)

1996-01-01T23:59:59.000Z

365

Raman/FTIR spectroscopy of oil shale retort gases  

DOE Green Energy (OSTI)

A Raman facility was assembled in order to aid in the evaluation of the feasibility of using Raman or FTIR spectroscopy for analyzing gas mixtures of interest in oil shale. Applications considered in oil shale research included both retort monitoring and laboratory kinetic studies. Both techniques gave limits of detection between 10 and 1000 ppM for ten representative pertinent gases. Both techniques are inferior as a general analytical technique for oil shale gas analysis in comparison with mass spectroscopy, which had detection limits between 1 and 50 ppM for the same gases. The conclusion of the feasibility study was to recommend that mass spectroscopic techniques be used for analyzing gases of interest to oil shale.

Richardson, J.H.; Monaco, S.B.; Sanborn, R.H.; Hirschfeld, T.B.; Taylor, J.R.

1982-08-01T23:59:59.000Z

366

Method and apparatus for two-dimensional spectroscopy  

SciTech Connect

Preferred embodiments of the invention provide for methods and systems of 2D spectroscopy using ultrafast, first light and second light beams and a CCD array detector. A cylindrically-focused second light beam interrogates a target that is optically interactive with a frequency-dispersed excitation (first light) pulse, whereupon the second light beam is frequency-dispersed at right angle orientation to its line of focus, so that the horizontal dimension encodes the spatial location of the second light pulse and the first light frequency, while the vertical dimension encodes the second light frequency. Differential spectra of the first and second light pulses result in a 2D frequency-frequency surface equivalent to double-resonance spectroscopy. Because the first light frequency is spatially encoded in the sample, an entire surface can be acquired in a single interaction of the first and second light pulses.

DeCamp, Matthew F. (Swarthmore, PA); Tokmakoff, Andrei (Lexington, MA)

2010-10-12T23:59:59.000Z

367

Free-Electron Laser-Powered Electron Paramagnetic Resonance Spectroscopy  

E-Print Network (OSTI)

Electron paramagnetic resonance (EPR) spectroscopy interrogates unpaired electron spins in solids and liquids to reveal local structure and dynamics; for example, EPR has elucidated parts of the structure of protein complexes that have resisted all other techniques in structural biology. EPR can also probe the interplay of light and electricity in organic solar cells and light-emitting diodes, and the origin of decoherence in condensed matter, which is of fundamental importance to the development of quantum information processors. Like nuclear magnetic resonance (NMR), EPR spectroscopy becomes more powerful at high magnetic fields and frequencies, and with excitation by coherent pulses rather than continuous waves. However, the difficulty of generating sequences of powerful pulses at frequencies above 100 GHz has, until now, confined high-power pulsed EPR to magnetic fields of 3.5 T and below. Here we demonstrate that ~1 kW pulses from a free-electron laser (FEL) can power a pulsed EPR spectrometer at 240 GHz...

Takahashi, S; Edwards, D T; van Tol, J; Ramian, G; Han, S; Sherwin, M S

2012-01-01T23:59:59.000Z

368

Photodissociation spectroscopy and dynamics of free radicals, clusters, and ions  

Science Conference Proceedings (OSTI)

The photodissociation spectroscopy and dynamics of free radicals and ions is studied to characterize the dissociative electronic states in these species. To accomplish this, a special method of radical production, based on the photodetachment of the corresponding negative ion, has been combined with the technique of fast beam photofragment translational spectroscopy. The photofragment yield as a function of photon energy is obtained, mapping out the dissociative and predissociative electronic states. Branching ratios to various product channels, the translational energy distributions of the fragments, and bond dissociation energies are then determined at selected photon energies. The detailed picture of photodissociation dynamics is provided with the aid of ab initio calculations and a statistical model to interpret the observed data. Important reaction intermediates in combustion reactions have been studied: CCO, C{sub 2}H{sub 5}O, and linear C{sub n} (n = 4--6).

Hyeon, Choi

1999-12-16T23:59:59.000Z

369

Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy  

NLE Websites -- All DOE Office Websites (Extended Search)

Dirac Charge Dynamcs in Graphene by Infrared Spectroscopy Print 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 by applying a gate voltage. The charge carriers in graphene can travel ballistically over great distances (~1 micron) without scattering. These unusual electronic properties make graphene a promising candidate for future nanoelectronics. Using infrared spectromicroscopy at ALS Beamline 1.4, a group of researchers from the University of California at San Diego, Columbia University, and the ALS has succeeded in probing the dynamical properties of the charge carriers in graphene with an accuracy never before achieved. Their results have uncovered signatures of many-body interactions in graphene and have demonstrated the potential of graphene for novel applications in optoelectronics.

370

Supplemental Report: Application of Emission Spectroscopy to Monitoring Technetium  

Science Conference Proceedings (OSTI)

This report provides supplemental information to an earlier report BNF-98-003-0199, ''Evaluation of Emission Spectroscopy for the On-Line Analysis of Technetium''. In this report data is included from real Hanford samples as well as for solutions spiked with technetium. This supplemental work confirms the ability of ICP-ES to monitor technetium as it breaks through an ion exchange process.

Spencer, W.A.

2000-07-27T23:59:59.000Z

371

Advances in Optical Spectroscopy and Imaging of Breast Lesions  

SciTech Connect

A review is presented of recent advances in optical imaging and spectroscopy and the use of light for addressing breast cancer issues. Spectroscopic techniques offer the means to characterize tissue components and obtain functional information in real time. Three-dimensional optical imaging of the breast using various illumination and signal collection schemes in combination with image reconstruction algorithms may provide a new tool for cancer detection and monitoring of treatment.

Demos, S; Vogel, A J; Gandjbakhche, A H

2006-01-03T23:59:59.000Z

372

Laser produced plasma diagnostics by cavity ringdown spectroscopy and applications  

SciTech Connect

Laser-produced plasmas have many applications for which detailed characterization of the plume is requested. Cavity ring-down spectroscopy is a versatile absorption method which provides data on the plume and its surroundings, with spatial and temporal resolution. The measured absorption line shapes contain information about angular and velocity distributions within the plume. In various plasmas we have observed molecules or metastable atoms which were not present in the emission spectra.

Milosevic, S. [Institute of Physics, Zagreb (Croatia)

2012-05-25T23:59:59.000Z

373

Spectroscopy of a Qubit Array via a Single Transmission Line  

E-Print Network (OSTI)

Frequency-selective readout for superconducting qubits opens the way towards scaling qubit circuits up without increasing the number of measurement lines. Here we demonstrate the readout of an array of 7 flux qubits located on the same chip. Each qubit is placed near an individual lambda/4 resonator which, in turn, is coupled to a common microwave transmission line. We performed spectroscopy of all qubits and determined their parameters in a single measurement run.

Jerger, M; Macha, P; Huebner, U; Lukashenko, A; Il'ichev, E; Ustinov, A V

2011-01-01T23:59:59.000Z

374

Rapid Compositional Analysis of Microalgae by NIR Spectroscopy  

DOE Green Energy (OSTI)

One of the challenges associated with the development of algal biofuels is the rapid determination of the composition of algae. The oil content in particular is important in a biofuels production process and selecting the right algal strain from a pool of potentially thousands of candidates remains difficult. This article discusses how near infrared (NIR) spectroscopy is a technology that could be used for distinguishing algal strains and more importantly, differentiating between high and low oil content of biomass.

Laurens, L. M. L.; Wolfrum, E. J.

2012-03-01T23:59:59.000Z

375

Measuring of exhaust gas emissions using absorption spectroscopy  

Science Conference Proceedings (OSTI)

This paper describes an optical fibre sensor for the detection of NOx (NO2 and NO) and CO2 in the exhaust system of a road vehicle. The measurement is based on a free path interaction zone which is interrogated using ... Keywords: absorption spectroscopy, air pollution, carbon dioxide, emissions measurement, exhaust gas emissions, gas sensors, infrared, nitrogen dioxide, nitrogen oxide, optical fibre sensors, ultraviolet, vehicle emissions

Eamonn Hawe; Gerard Dooly; Colin Fitzpatrick; Paul Chambers; Elfed Lewis; W. Z. Zhao; T. Sun; K. T. V. Grattan; M. Degner; H. Ewald; S. Lochmann; G. Bramman; C. Wei; D. Hitchen; J. Lucas; A. Al-Shamma'a; E. Merlone-Borla; P. Faraldi; M. Pidria

2008-02-01T23:59:59.000Z

376

Nonlinearity sensing via photon-statistics excitation spectroscopy  

SciTech Connect

We propose photon-statistics excitation spectroscopy as an adequate tool to describe the optical response of a nonlinear system. To this end we suggest to use optical excitation with varying photon statistics as another spectroscopic degree of freedom to gather information about the system in question. The responses of several simple model systems to excitation beams with different photon statistics are discussed. Possible spectroscopic applications in terms of identifying lasing operation are pointed out.

Assmann, Marc; Bayer, Manfred [Experimentelle Physik 2, Technische Universitaet Dortmund, D-44221 Dortmund (Germany)

2011-11-15T23:59:59.000Z

377

Application of photothermal deflection spectroscopy to electrochemical interfaces  

DOE Green Energy (OSTI)

This dissertation discusses the theory and practice of Photothermal Deflection Spectroscopy (PDS, which is also known as probe beam deflection spectroscopy, PBDS, probe deflection technique, and mirage effect spectroscopy) with respect to electrochemical systems. Much of the discussion is also relevant to non-electrochemical systems. PDS can measure the optical absorption spectrum of interfaces and concentration gradients in the electrolyte adjacent to the electrode. These measurements can be made on a wide variety of electrode surfaces and can be performed under dynamic conditions. The first three chapters discuss the theory of the phenomena that can be detected by PDS, and the equipment used in a PDS system. A secondary gradient technique'' is proposed, which places the probe beam on the back of an electrode. The results of a numerical model yield a method for determining the offset of the probe beam from the electrode surface based on the frequency response of the PDS signal. The origin and control of noise in the PDS signal are discussed. A majority of the signal noise appears to be acoustic in origin. The electrochemical oxidation of platinum is used to demonstrate that PDS has sub-monolayer sensitivity necessary to study interfacial chemistry. The results allow us to propose a two-reaction oxidation mechanism: the platinum is electrochemically oxidized to form platinum dihydroxide and dehydrated by a non-electrochemical second-order reaction. The final chapter discusses the relation of PDS to similar and competing techniques, and considers possibilities for the future of the technique.

Rudnicki, J.D.; McLarnon, F.R.; Cairns, E.J.

1992-03-01T23:59:59.000Z

378

Application of photothermal deflection spectroscopy to electrochemical interfaces  

DOE Green Energy (OSTI)

This dissertation discusses the theory and practice of Photothermal Deflection Spectroscopy (PDS, which is also known as probe beam deflection spectroscopy, PBDS, probe deflection technique, and mirage effect spectroscopy) with respect to electrochemical systems. Much of the discussion is also relevant to non-electrochemical systems. PDS can measure the optical absorption spectrum of interfaces and concentration gradients in the electrolyte adjacent to the electrode. These measurements can be made on a wide variety of electrode surfaces and can be performed under dynamic conditions. The first three chapters discuss the theory of the phenomena that can be detected by PDS, and the equipment used in a PDS system. A ``secondary gradient technique`` is proposed, which places the probe beam on the back of an electrode. The results of a numerical model yield a method for determining the offset of the probe beam from the electrode surface based on the frequency response of the PDS signal. The origin and control of noise in the PDS signal are discussed. A majority of the signal noise appears to be acoustic in origin. The electrochemical oxidation of platinum is used to demonstrate that PDS has sub-monolayer sensitivity necessary to study interfacial chemistry. The results allow us to propose a two-reaction oxidation mechanism: the platinum is electrochemically oxidized to form platinum dihydroxide and dehydrated by a non-electrochemical second-order reaction. The final chapter discusses the relation of PDS to similar and competing techniques, and considers possibilities for the future of the technique.

Rudnicki, J.D.; McLarnon, F.R.; Cairns, E.J.

1992-03-01T23:59:59.000Z

379

Raman spectroscopy on simple molecular systems at very high density  

DOE Green Energy (OSTI)

We present an overview of how Raman spectroscopy is done on simple molecular substances at high pressures. Raman spectroscopy is one of the most powerful tools for studying these substances. It is often the quickest means to explore changes in crystal and molecular structures, changes in bond strength, and the formation of new chemical species. Raman measurements have been made at pressures up to 200 GPa (2 Mbar). Even more astonishing is the range of temperatures (4-5200/degree/K) achieved in various static and dynamic (shock-wave) pressure experiments. One point we particularly wish to emphasize is the need for a good theoretical understanding to properly interpret and use experimental results. This is particularly true at ultra-high pressures, where strong crystal field effects can be misinterpreted as incipient insulator-metal transitions. We have tried to point out apparatus, techniques, and results that we feel are particularly noteworthy. We have also included some of the /open quotes/oral tradition/close quotes/ of high pressure Raman spectroscopy -- useful little things that rarely or never appear in print. Because this field is rapidly expanding, we discuss a number of exciting new techniques that have been informally communicated to us, especially those that seem to open new possibilities. 58 refs., 18 figs.

Schiferl, D.; LeSar, R.S.; Moore, D.S.

1988-01-01T23:59:59.000Z

380

Measurement of Carbon for Carbon Sequestration and Site Monitoring,  

Science Conference Proceedings (OSTI)

Laser induced breakdown spectroscopy (LIBS) is basically an emission spectroscopy technique where atoms and ions are primarily formed in their excited states as a result of interaction between a tightly focused laser beam and the material sample. The interaction between matter and high-density photons generates a plasma plume, which evolves with time and may eventually acquire thermodynamic equilibrium. One of the important features of this technique is that it does not require any sample preparation, unlike conventional spectroscopic analytical techniques. Samples in the form of solids, liquids, gels, gases, plasmas and biological materials (like teeth, leaf or blood) can be studied with almost equal ease. LIBS has rapidly developed into a major analytical technology with the capability of detecting all chemical elements in a sample, of real- time response, and of close-contact or stand-off analysis of targets. The present book has been written by active specialists in this field, it includes the basic principles, the latest developments in instrumentation and the applications of LIBS . It will be useful to analytical chemists and spectroscopists as an important source of information and also to graduate students and researchers engaged in the fields of combustion, environmental science, and planetary and space exploration.

Martin, Madhavi Z [ORNL; Wullschleger, Stan D [ORNL; Garten Jr, Charles T [ORNL; Palumbo, Anthony Vito [ORNL

2007-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


381

Photo-oxidation of Ge Nanocrystals: Kinetic Measurements by InSitu Raman Spectroscopy  

SciTech Connect

Ge nanocrystals are formed in silica by ion beam synthesis and are subsequently exposed by selective HF etching of the silica. Under ambient conditions, the exposed nanocrystals are stable after formation of a protective native oxide shell of no more than a few monolayers. However, under visible laser illumination at room temperature and in the presence of O{sub 2}, the nanocrystals rapidly oxidize. The oxidation rate was monitored by measuring the Raman spectra of the Ge nanocrystals in-situ. The intensity ratio of the anti-Stokes to the Stokes line indicated that no significant laser-induced heating of illuminated nanocrystals occurs. Therefore, the oxidation reaction rate enhancement is due to a photo-chemical process. The oxidation rate varies nearly linearly with the logarithm of the laser intensity, and at constant laser intensity the rate increases with increasing photon energy. These kinetic measurements, along with the power dependencies, are described quantitatively by an electron active oxidation mechanism involving tunneling of optically excited electrons through the forming oxide skin and subsequent transport of oxygen ions to the Ge nanocrystal surface.

Sharp, I.D.; Xu, Q.; Yuan, C.W.; Beeman, J.W.; Ager III, J.W.; Chrzan, D.C.; Haller, E.E.

2006-11-22T23:59:59.000Z

382

Pulsed laser-induced charge collection in GaAs MESFETs  

Science Conference Proceedings (OSTI)

Pulsed picosecond lasers with variable wavelength have been used to investigate the details of charge collection in GaAs MESFETs. In short gate-length devices, charge collection at the drain may be much larger than at the gate and greater than the charge produced by the laser pulses.

Knudson, A.R.; Campbell, A.B.; McMorrow (Naval Research Lab., Washington, DC (USA)); Buchner, S.; Kang, K. (Martin Marietta Labs., Baltimore, MD (USA)); Weatherford, T. (SFA Inc., Landover, MD (US)); Srinivas, V.; Swartzlander, G.A. Jr.; Chen, Y.J. (Maryland Univ., Baltimore, MD (USA))

1990-12-01T23:59:59.000Z

383

Measuring OH and HO2 in the Troposphere by Laser-Induced Fluorescence at Low Pressure  

Science Conference Proceedings (OSTI)

The hydroxyl radical OH oxidizes many lime gases in the atmosphere. It initiates and then participates in chemical reactions that lead to such phenomena as photochemical smog, acid rain, and stratospheric ozone depletion. Because OH is so ...

William H. Brune; Philip S. Stevens; James H. Mather

1995-10-01T23:59:59.000Z

384

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

SciTech Connect

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.

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

2006-10-01T23:59:59.000Z

385

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

DOE Patents (OSTI)

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.

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

2010-11-23T23:59:59.000Z

386

Detecting and Imaging He2 Molecules in Superfluid Helium by Laser-Induced Fluorescence  

E-Print Network (OSTI)

Dissertation Director: Professor Daniel N. McKinsey September 2008 #12;Copyright c 2008 by Wade G. Rellergert

McKinsey, Daniel

387

Velocity distribution measurements in atomic beams generated using laser induced back-ablation  

E-Print Network (OSTI)

We present measurements of the velocity distribution of calcium atoms in an atomic beam generated using a dual-stage laser back-ablation apparatus. Distributions are measured using a velocity selective Doppler time-of-flight technique. They are Boltzmann-like with rms velocities corresponding to temperatures above the melting point for calcium. Contrary to a recent report in the literature, this method does not generate a sub-thermal atomic beam.

Denning, A; Lee, S; Ammonson, M; Bergeson, S D

2008-01-01T23:59:59.000Z

388

MOLECULAR BEAM STUDIES OF IR LASER INDUCED MULTIPHOTON DISSOCIATION AND VIBRATIONAL PREDISSOCIATION  

E-Print Network (OSTI)

However, the dissociation rate increases rapidly with thehow the dissociation rate increases with the excess energy (9 the dissociation rate increases faster with excess energy,

Lee, Yuan T.

2013-01-01T23:59:59.000Z

389

NON-CONTACT MICROSCALE MANIPULATION USING LASER-INDUCED CONVECTION FLOWS  

E-Print Network (OSTI)

Hulin-Hubard and Daniel Lemoal. Finally my warmest gratitude goes to those whose presence in my life of the Heisenberg equation must thus be taken out to a superior order. This approach was developed by Bogoli- ubov

Paris-Sud XI, Université de

390

Interfaces in Thermoplastic Composites Probed by Laser-Induced Acoustic Emission  

Science Conference Proceedings (OSTI)

The mechanical properties and durability of carbon fiber composites depend not only on the properties of the constituent fiber and matrix but also on the quality of the interfacial bond. Many of the techniques for evaluating this bonding rely on model ...

Prosser W. H.; Hinkley J. A.

1994-01-01T23:59:59.000Z

391

Laser-induced damage in dielectrics with nanosecond to subpicosecond pulses  

Science Conference Proceedings (OSTI)

We report extensive measurements of damage thresholds for fused silica and calcium fluoride at 1053 and 526 nm for pulse durations [tau] ranging from 270 fs to 1 ns. Qualitative differences in the morphology of damage and a departure from the diffusion-dominated [tau][sup 1/2] scaling indicate that damage results from plasma formation and ablation for [tau][le]10 ps and from conventional melting and boiling for [tau][gt]100 ps. A theoretical model based on electron production via multiphoton ionization, Joule heating, and collisional (avalanche) ionization is in good agreement with experimental results.

Stuart, B.C.; Feit, M.D.; Rubenchik, A.M.; Shore, B.W.; Perry, M.D. (Lawrence Livermore National Laboratory, P.O. Box 808, L-443, Livermore, California 94550 (United States))

1995-03-20T23:59:59.000Z

392

Crater effects on H and D emission from laser induced low-pressure helium plasma  

Science Conference Proceedings (OSTI)

An experimental study has been performed on the effects of crater depth on the hydrogen and deuterium emission intensities measured from laser plasmas generated in low-pressure helium ambient gas from zircaloy-4 samples doped with different H and D impurity concentrations as well as a standard brass sample for comparison. The results show that aside from emission of the host atom, the emission intensities of other ablated atoms of significantly smaller masses as well as that of the He atom generally exhibit relatively rapid initial decline with increasing crater depth. This trend was found to have its origin in the decreasing laser power density arriving at the crater bottom and thereby weakened the shock wave generated in the crater. As the crater deepened, the declining trend of the intensity appeared to level off as a result of compensation of the decreasing laser power density by the enhanced plasma confinement at increasing crater depth. Meanwhile, the result also reveals the significant contribution of the He-assisted excitation process to the doped hydrogen and deuterium emission intensities, leading to similar crater-depth dependent variation patterns in contrast to that associated with the surface water, with growing dominance of this common feature at the later stage of the plasma expansion. Therefore, a carefully chosen set of gate delay and gate width which are properly adapted to the crater-depth dependent behavior of the emission intensity may produce the desired intrinsic emission data for quantitative depth profiling of H impurity trapped inside the zircaloy wall.

Pardede, Marincan; Lie, Tjung Jie; Kurniawan, Koo Hendrik [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Kembangan, Jakarta Barat 11630 (Indonesia); Niki, Hideaki; Fukumoto, Kenichi [Program of Nuclear Power and Energy Safety Engineering, Graduate School of Engineering, Fukui University, Fukui 910-8507 (Japan); Maruyama, Tadashi [Integrated Research Institute, Tokyo Institute of Technology, 4259 Nagatsuda-cho, Midori-ku, Yokohama 226-8503 (Japan); Kagawa, Kiichiro [Department of Physics, Faculty of Education and Regional Studies, Fukui University, 9-1 bunkyo 3-chome, Fukui 910-8507 (Japan); Tjia, May On [Physics of Magnetism and Photonics Research Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia)

2009-09-15T23:59:59.000Z

393

DETECTION OF ULTRA-TRACE LEVELS OF URANIUM IN AQUEOUS SAMPLES BY LASER INDUCED FLUORESCENCE SPECTROMETRY  

E-Print Network (OSTI)

uranium have been reported in the chemical literature (1), many of which involve initial separation or enrichment

Perry, Dale L.

2012-01-01T23:59:59.000Z

394

Generation of laser-induced cavitation bubbles with a digital hologram  

E-Print Network (OSTI)

, in which a high power light emitting diode (LED, model P7, Seoul Semiconductor, Seoul, South Korea with a homebuilt strobe consisting of a high power light emitting diode (LED) and a current amplifier. 3. Results

Ohl, Claus-Dieter

395

Glass-wool study of laser-induced spin currents en route to hyperpolarized Cs salt  

SciTech Connect

The nuclear spin polarization of optically pumped Cs atoms flows to the surface of Cs hydride in a vapor cell. A fine glass wool lightly coated with the salt helps greatly increase the surface area in contact with the pumped atoms and enhance the spin polarization of the salt nuclei. Even though the glass wool randomly scatters the pump light, the atomic vapor can be polarized with unpolarized light in a magnetic field. The measured enhancement in the salt enables study of the polarizations of light and atomic nuclei very near the salt surface.

Ishikawa, Kiyoshi [Graduate School of Material Science, University of Hyogo, Ako-gun, Hyogo 678-1297 (Japan)

2011-07-15T23:59:59.000Z

396

Identification Of Natural Dyes On Archaeological Textile Objects Using Laser Induced Fluorescent Technique  

SciTech Connect

This study aims to evaluate the use of Laser Fluorescent as a non-destructive technique for identification of natural dyes on archaeological textile objects. In this study wool textile samples were dyed with 10 natural dyes such as cochineal, cutch, henna, indigo, Lac, madder, safflower, saffron, sumac and turmeric. These dyes common present on archaeological textile objects to be used as standard dyed textile samples. These selected natural dyes will be used as known references that can be used a guide to identify unknown archaeological dyes. The dyed textile samples were investigated with laser radiation in different wavelengths to detect the best wavelengths for identification each dye. This study confirms that Laser Florescent is very useful and a rapid technique can be used as a non-destructive technique for identification of natural dyes on archaeological textile objects. The results obtained with this study can be a guide for all conservators in identification of natural organic dyes on archaeological textile objects.

Abdel-Kareem, O. [Conservation Department, Faculty of Archaeology, Cairo University (Egypt); Eltokhy, A.; Harith, M. A. [National Institute of Laser Enhanced Science, Cairo University (Egypt)

2011-09-22T23:59:59.000Z

397

Laser-induced separation of hydrogen isotopes in the liquid phase  

DOE Patents (OSTI)

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.

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)

1980-01-01T23:59:59.000Z

398

Spectroscopic Studies of Pulsed-Laser-Induced Damage Sites in Heated CaF2 Crystals  

SciTech Connect

Proceedings contain all papers presented at the 13th Symposium on Optical Materials for High-Powered Lasers, held at the National Institute of Standards and Technology in Boulder, CO, 28 Sept. - 1 Oct. 1998.

Bozlee, Brian J.; Exarhos, Gregory J.; Teel, Randy W.

1999-09-01T23:59:59.000Z

399

Planar laser-induced fluorescence of nitric oxide in isomeric butanol and butane stagnation flames.  

E-Print Network (OSTI)

??The significant efforts to reduce global fossil fuel dependence have led to the development of biofuels as an alternative. Despite their growing significance, alcohol biofuels… (more)

Chung, Gregory

2012-01-01T23:59:59.000Z

400

Determination of strain localization in aluminum alloys using laser-induced photoelectron emission  

E-Print Network (OSTI)

emission during exposure to ultraviolet light. We report measurements of photoelectron emission during the broad face of the gauge section is exposed to pulsed excimer laser radiation 248 nm . We show tests, but are susceptible to changes in internal microstructural accompanying strain hardening.6

Dickinson, J. Thomas

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

Determination of the transient electron temperature in a femtosecond-laser-induced air plasma filament  

Science Conference Proceedings (OSTI)

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.

Sun Zhanliang; Chen Jinhai; Rudolph, Wolfgang [University of New Mexico, Department of Physics and Astronomy, Albuquerque, New Mexico 87131 (United States)

2011-04-15T23:59:59.000Z

402

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

SciTech Connect

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.

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

2011-12-27T23:59:59.000Z

403

Induced Current Characteristics Due to Laser Induced Plasma and Its Application to Laser Processing Monitoring  

Science Conference Proceedings (OSTI)

In laser processing, suitable conditions for laser and gas play important role in ensuring a high quality of processing. To determine suitable conditions, we employed the electromagnetic phenomena associated with laser plasma generation. An electrode circuit was utilised to detect induced current due to the fast electrons propelled from the material during laser material processing. The characteristics of induced current were examined by changing parameters such as supplied voltage, laser pulse energy, number of laser shots, and type of ambient gas. These characteristics were compared with the optical emission characteristics. It was shown that the induced current technique proposed in this study is much more sensitive than the optical method in monitoring laser processing, that is to determine the precise focusing condition, and to accurately determine the moment of completion of laser beam penetration. In this study it was also shown that the induced current technique induced by CW CO{sub 2} laser can be applied in industrial material processing for monitoring the penetration completion in a stainless steel plate drilling process.

Madjid, Syahrun Nur; Idris, Nasrullah [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Banda Aceh (Indonesia); Kurniawan, Koo Hendrik [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Kagawa, Kiichiro [Department of Physics, Faculty of Education and Regional Studies, University of Fukui, 9-1 Bunkyo 3-chome, Fukui 910-8507 (Japan)

2011-03-30T23:59:59.000Z

404

Coherent optical phonon spectroscopy studies of femtosecond-laser modified Sb{sub 2}Te{sub 3} films  

Science Conference Proceedings (OSTI)

We performed time-resolved reflectivity measurements to monitor changes in optical phonon modes in Sb{sub 2}Te{sub 3} thin films under femtosecond laser irradiation. We found that a phonon mode at 3.64 THz appears after high-fluence laser irradiation, in addition to the phonon modes of Sb{sub 2}Te{sub 3}. We determined that the additional mode is due to Te segregation as a result of laser-induced decomposition of the Sb{sub 2}Te{sub 3} film. This experiment clearly illustrates the irreversible effects of femtosecond laser irradiation during the measurement of coherent optical phonon dynamics in Sb{sub 2}Te{sub 3}.

Li Yuwei; Wang Guoyu [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Center for Solar and Thermal Energy Conversion, University of Michigan, Michigan 48109 (United States); Stoica, Vladimir A. [Center for Solar and Thermal Energy Conversion, University of Michigan, Michigan 48109 (United States); Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States); Endicott, Lynn [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Uher, Ctirad; Clarke, Roy [Department of Physics, University of Michigan, Ann Arbor, Michigan 48109 (United States); Center for Solar and Thermal Energy Conversion, University of Michigan, Michigan 48109 (United States); Applied Physics Program, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2010-10-25T23:59:59.000Z

405

Infrared spectroscopy and hydrogen isotope geochemistry of hydrous silicate glasses  

DOE Green Energy (OSTI)

The focus of this project is the combined appication of infrared spectroscopy and stable isotope geochemistry to the study of hydrogen-bearing species dissolved in silicate melts and glasses. We are conducting laboratory experiments aimed at determining the fractionation of D and H between melt species (OH and H{sub 2}O) and hydrous vapor and the diffusivities of these species in glasses and melts. Knowledge of these parameters is critical to understanding the behavior of hydrogen isotopes during igneous processes and hydrothermal processes. These results also could be valuable in application of glass technology to development of nuclear waste disposal strategies.

Epstein, S.; Stolper, E.

1992-01-01T23:59:59.000Z

406

Application of Raman spectroscopy to high-temperature analytical measurements  

Science Conference Proceedings (OSTI)

There are numerous analytical applications of scatter-emission and/or absorption spectroscopy applied to liquids and solids at 0 to 350 C. This paper describes an all-silica fiberoptic probe which is useful for spectral analyses from 0 to 1600 K and can be used in harsh chemical environments. The probe has been used for Raman spectral analyses of many molten salt and solid material systems to 1000 C. It has applications for such studies at higher temperature ranges. The instrumentation required along with the demonstrated and proposed applications of the all-silica probe are presented and discussed.

Young, J.P.; Dai, S.; Lee, Y.; Xizo, H.

1997-01-01T23:59:59.000Z

407

Near-infrared spectroscopy. Innovative technology summary report  

Science Conference Proceedings (OSTI)

A near-infrared (NIR) spectroscopy system with a remote fiber-optic probe was developed and demonstrated to measure the water content of high-level radioactive wastes from the underground storage tanks at the Hanford Site in richland Washington. The technology was developed as a cost-effective and safer alternative to the thermogravimetric analysis (TGA) technique in use as the baseline. This work was supported by the Tanks Focus Area (TFA) within the Department of Energy`s (DOE) Office of Science and Technology (OST) in cooperation with the Hanford Tank Waste Remediation System (TWRS) Program.

Not Available

1999-07-01T23:59:59.000Z

408

8th international conference on electronic spectroscopy and structure  

SciTech Connect

Gathering from 33 countries around the world, 408 registrants and a number of local drop-in participants descended on the Clark Kerr Campus of the University of California, Berkeley, from Monday, August 7 through Saturday, August 12, 2000 for the Eighth International Conference on Electronic Structure and Spectroscopy (ICESS8). At the conference, participants benefited from an extensive scientific program comprising more than 100 oral presentations (plenary lectures and invited and contributed talks) and 330 poster presentations, as well as ample time for socializing and a tour of the Advanced Light Source (ALS) at the nearby Lawrence Berkeley National Laboratory.

Robinson, Art

2000-10-16T23:59:59.000Z

409

Position-Sensitive Nuclear Spectroscopy with Pixel Detectors  

SciTech Connect

State-of-the-art hybrid semiconductor pixel detectors such as Medipix2 are suitable for energy- and position-sensitive nuclear spectroscopy. In addition to excellent energy- and spatial-resolution, these devices can operate in spectroscopic, single-quantum counting and/or on-line tracking mode. A devoted compact USB-readout interface provides functionality and ease of operation. The compact and versatile Medipix2/USB radiation camera provides visualization, vacuum and room-temperature operation as a real-time portable active nuclear emulsion.

Granja, Carlos; Vykydal, Zdenek; Jakubek, Jan; Pospisil, Stanislav [Institute of Experimental and Applied Physics, Czech Technical University in Prague Horska 3a/22, 12800 Prague 2 (Czech Republic)

2007-10-26T23:59:59.000Z

410

Elastic properties of gamma-Pu by resonant ultrasound spectroscopy  

Science Conference Proceedings (OSTI)

Despite intense experimental and theoretical work on Pu, there is still little understanding of the strange properties of this metal. We used resonant ultrasound spectroscopy method to investigate the elastic properties of pure polycrystalline Pu at high temperatures. Shear and longitudinal elastic moduli of the {gamma}-phase of Pu were determined simultaneously and the bulk modulus was computed from them. A smooth linear and large decrease of all elastic moduli with increasing temperature was observed. We calculated the Poisson ratio and found that it increases from 0.242 at 519K to 0.252 at 571K.

Migliori, Albert [Los Alamos National Laboratory; Betts, J [Los Alamos National Laboratory; Trugman, A [Los Alamos National Laboratory; Mielke, C H [Los Alamos National Laboratory; Mitchell, J N [Los Alamos National Laboratory; Ramos, M [Los Alamos National Laboratory; Stroe, I [WORXESTER, MA

2009-01-01T23:59:59.000Z

411

Results from Point Contact Tunnelling Spectroscopy and Atomic Layer Deposition  

SciTech Connect

We have shown previously that magnetic niobium oxides can influence the superconducting density of states at the surface of cavity-grade niobium coupons. We will present recent results obtained by Point Contact Tunneling spectroscopy (PCT) on coupons removed from hot and cold spots in a niobium cavity, as well as a comparative study of magnetic oxides on mild baked/unbaked electropolished coupons. We will also describe recent results obtained from coated cavities, ALD films properties and new materials using Atomic Layer Deposition (ALD).

Proslier, Th. [Illinois Institute of Technology; Zasadzinski, J. [Illinois Institute of Technology; Ciovati, Gianluigi [JLAB; Kneisel, Peter K. [JLAB; Elam, J. W. [ANL; Norem, J. [ANL; Pellin, M. J. [ANL

2009-11-01T23:59:59.000Z

412

Excited-Nucleon Spectroscopy with 2+1 Fermion Flavors  

E-Print Network (OSTI)

We present progress made by the Hadron Spectrum Collaboration (HSC) in determining the tower of excited nucleon states using 2+1-flavor anisotropic clover lattices. The HSC has been investigating interpolating operators projected into irreducible representations of the cubic group in order to better calculate two-point correlators for nucleon spectroscopy; results are published for quenched and 2-flavor anisotropic Wilson lattices. In this work, we present the latest results using a new technique, distillation, which allows us to reach higher statistics than before. Future directions will be outlined at the end.

Saul Cohen; John M. Bulava; Justin Foley; Colin Morningstar; Ricky Wong; Robert G. Edwards; Balint Joo; David G. Richards; K. Jimmy Juge; Huey-Wen Lin; Nilmani Mathur; Michael J. Peardon; Sinead M. Ryan

2009-11-17T23:59:59.000Z

413

Excited-Nucleon Spectroscopy with 2+1 Fermion Flavors  

Science Conference Proceedings (OSTI)

We present progress made by the Hadron Spectrum Collaboration (HSC) in determining the tower of excited nucleon states using 2+1-flavor anisotropic clover lattices. The HSC has been investigating interpolating operators projected into irreducible representations of the cubic group in order to better calculate two-point correlators for nucleon spectroscopy; results are published for quenched and 2-flavor anisotropic Wilson lattices. In this work, we present the latest results using a new technique, distillation, which allows us to reach higher statistics than before. Future directions will be outlined at the end.

Cohen, Saul; Foley, Justin; Morningstar, Colin; Wong, Ricky; Edwards, Robert G; Joo, Balint; Richards, David G; Juge, Jimmy; Lin, Huey-Lin; Mathur, Nilmani; Peardon, Micheal J

2010-01-01T23:59:59.000Z

414

Holdup Measures on an SRNL Mossbauer Spectroscopy Instrument  

SciTech Connect

Gamma-ray holdup measurements of a Mossbauer spectroscopy instrument are described and modeled. In the qualitative acquisitions obtained in a low background area of Savannah River National Laboratory, only Am-241 and Np-237 activity were observed. The Am-241 was known to be the instrumental activation source, while the Np-237 is clearly observed as a source of contamination internal to the instrument. The two sources of activity are modeled separately in two acquisition configurations using two separate modeling tools. The results agree well, demonstrating a content of (1980 {+-} 150) {mu}Ci Am-241 and (110 {+-} 50) {mu}Ci of Np-237.

Dewberry, R.; Brown, T.; Salaymeh, S.

2010-05-05T23:59:59.000Z

415

Band Structure Asymmetry of Bilayer Graphene Revealed by Infrared Spectroscopy  

Science Conference Proceedings (OSTI)

We report on infrared spectroscopy of bilayer graphene integrated in gated structures. We observe a significant asymmetry in the optical conductivity upon electrostatic doping of electrons and holes. We show that this finding arises from a marked asymmetry between the valence and conduction bands, which is mainly due to the inequivalence of the two sublattices within the graphene layer and the next-nearest-neighbor interlayer coupling. From the conductivity data, the energy difference of the two sublattices and the interlayer coupling energy are directly determined.

Li, Z.Q.; Henriksen, E.A.; Jiang, Z.; Hao, Zhao; Martin, Michael C.; Kim, P.; Stormer, H.L.; Basov, Dimitri N.

2008-12-10T23:59:59.000Z

416

10 Questions for a Spectroscopy Expert: Nancy Hess | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Spectroscopy Expert: Nancy Hess Spectroscopy Expert: Nancy Hess 10 Questions for a Spectroscopy Expert: Nancy Hess April 14, 2011 - 4:34pm Addthis Nancy Hess | Photo Courtesy of Pacific Northwest National Lab (PNNL) Nancy Hess | Photo Courtesy of Pacific Northwest National Lab (PNNL) Niketa Kumar Niketa Kumar Public Affairs Specialist, Office of Public Affairs "I have always enjoyed the beauty and the complexity of processes in the natural world -- Spectroscopy gives you that insight." Nancy Hess, Spectroscopy Expert Meet Nancy Hess -- an expert in spectroscopy (i.e. the change in light intensity and/or frequency resulting from its interaction with matter that gives information about electronic structure, geometry and chemical bonds). At Pacific Northwest National Lab (PNNL), she leads the

417

Charge exchange spectroscopy as a fast ion diagnostic on TEXTOR  

SciTech Connect

An upgraded charge exchange spectroscopy diagnostic has been taken into operation at the TEXTOR tokamak. The angles of the viewing lines with the toroidal magnetic field are close to the pitch angles at birth of fast ions injected by one of the neutral beam injectors. Using another neutral beam for active spectroscopy, injected counter the direction in which fast ions injected by the first beam are circulating, we can simultaneously measure a fast ion tail on the blue wing of the D{sub {alpha}} spectrum while the beam emission spectrum is Doppler shifted to the red wing. An analysis combining the two parts of the spectrum offers possibilities to improve the accuracy of the absolute (fast) ion density profiles. Fast beam modulation or passive viewing lines cannot be used for background subtraction on this diagnostic setup and therefore the background has to be modeled and fitted to the data together with a spectral model for the slowing down feature. The analysis of the fast ion D{sub {alpha}} spectrum obtained with the new diagnostic is discussed.

Delabie, E.; Jaspers, R. J. E.; Hellermann, M. G. von [FOM-Rijnhuizen, EURATOM-FOM, NL-3430 BE Nieuwegein (Netherlands); Nielsen, S. K. [Association EURATOM-Risoe National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Marchuk, O. [Forschungszentrum Juelich, EURATOM-FZJ, D-52424 Juelich (Germany)

2008-10-15T23:59:59.000Z

418

Mechanized selection of fiber optic arrays for spectroscopy measurements  

Science Conference Proceedings (OSTI)

A 400-fiber optic bundle has been installed as part of the beam emission spectroscopy diagnostic for measuring density fluctuations in Tokamak Fusion Test Reactor. One hundred bundles, each composed of four 1-mm-diam fibers, transmit {ital H}{sub {alpha}} light 50 m away to 20 detectors located outside the radiation area. To shorten the time spent manually switching the bundles among the 20 detectors, a mechanized fiber selector was installed. The fiber bundles were separated into radial and poloidal groups of 220 and 180 fibers and coupled by a computer-controlled, motorized precision translation stage. The fibers were fastened to a plate and placed less than 0.003 in. from an identical plate that holds a similar array of fibers which transmits the light to the detectors. Holding the fiber spacing tolerance to 0.001 in., and using refractive index matching fluid, the highest measured loss was less than 0.5 dB, and generally was very small compared to the fiber's insertion loss. The stages are actuated with precision encoded micrometers and controlled by the beam emission spectroscopy VAX-resident software via a RS-232/CAMAC interface allowing arbitrary selections of fibers between plasma discharges with a 5 min repetition rate.

Paul, S.F.; Cylinder, D.; Durst, R.D.; Fonck, R.J. (Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States))

1992-10-01T23:59:59.000Z

419

Ultrafast X-ray and 2-dimensional UV Spectroscopy of TiO2 ...  

Science Conference Proceedings (OSTI)

Presentation Title, Ultrafast X-ray and 2-dimensional UV Spectroscopy of TiO2 Nanoparticles. Author(s), Majed Chergui. On-Site Speaker (Planned), Majed ...

420

Anatomy-Based Algorithms for Detecting Oral Cancer Using Reflectance and Fluorescence Spectroscopy  

E-Print Network (OSTI)

OBJECTIVES: We used reflectance and fluorescence spectroscopy to noninvasively and quantitatively distinguish benign from dysplastic/malignant oral lesions. We designed diagnostic algorithms to account for differences in ...

McGee, Sasha

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Scanning angle Raman spectroscopy: Investigation of Raman scatter enhancement techniques for chemical analysis  

SciTech Connect

This thesis outlines advancements in Raman scatter enhancement techniques by applying evanescent fields, standing-waves (waveguides) and surface enhancements to increase the generated mean square electric field, which is directly related to the intensity of Raman scattering. These techniques are accomplished by employing scanning angle Raman spectroscopy and surface enhanced Raman spectroscopy. A 1064 nm multichannel Raman spectrometer is discussed for chemical analysis of lignin. Extending dispersive multichannel Raman spectroscopy to 1064 nm reduces the fluorescence interference that can mask the weaker Raman scattering. Overall, these techniques help address the major obstacles in Raman spectroscopy for chemical analysis, which include the inherently weak Raman cross section and susceptibility to fluorescence interference.

Meyer, Matthew W. [Ames Laboratory

2013-03-14T23:59:59.000Z

422

Characterization for the Onset of Crystallization of Amorphous to Microcrystalline Silicon by Optical Spectroscopies  

DOE Green Energy (OSTI)

We study the amorphous to microcrystalline silicon films made at three laboratories by using Raman, photoluminescence- and optical-abosrption spectroscopies.

Yue, G.; Han, D.; Ganguly, G.; Wang, Q.; Yang, J.; Guha, S.

2000-01-01T23:59:59.000Z

423

SPIN POLARIZED PHOTOELECTRON SPECTROSCOPY AS A PROBE OF MAGNETIC SYSTEMS.  

SciTech Connect

Spin-polarized photoelectron spectroscopy has developed into a versatile tool for the study of surface and thin film magnetism. In this chapter, we examine the methodology of the technique and its recent application to a number of different problems. We first examine the photoemission process itself followed by a detailed review of spin-polarization measurement techniques and the related experimental requirements. We review studies of spin polarized surface states, interface states and quantum well states followed by studies of the technologically important oxide systems including half-metallic transition metal oxides, ferromagnet/oxide interfaces and the antiferromagnetic cuprates that exhibit high Tc Superconductivity. We also discuss the application of high-resolution photoemission with spin resolving capabilities to the study of spin dependent self energy effects.

JOHNSON, P.D.; GUNTHERODT, G.

2006-11-01T23:59:59.000Z

424

Application of nonlinear wave modulation spectroscopy to discern material damage  

SciTech Connect

Materials containing structural damage have a far greater nonlinear elastic response than materials with no structural damage. This is the basis for nonlinear wave diagnostics of damage, methods which are remarkably sensitive to the detection and progression of damage in materials. Here the authors describe one nonlinear method, the application of harmonics and sum and difference frequency to discern damage in materials. The method is termed Nonlinear Wave Modulation Spectroscopy (NWMS). It consists of exciting a sample with continuous waves of two separate frequencies simultaneously, and inspecting the harmonics of the two waves, and their sum and difference frequencies (sidebands). Undamaged materials are essentially linear in their response to the two waves, while the same material, when damaged, becomes highly nonlinear, manifested by harmonics and sideband generation. The authors illustrate the method by experiments on uncracked and cracked plexiglass and sandstone samples, and by applying it to intact and damaged engine components.

Johnson, P.A. [Los Alamos National Lab., NM (United States); Sutin, A. [Stevens Inst. of Tech., Hoboken, NJ (United States); Abeele, K.E.A. van den [Catholic Univ. Leuven (Belgium). Dept. of Building Physics

1999-04-01T23:59:59.000Z

425

Introducing many-body physics using atomic spectroscopy  

E-Print Network (OSTI)

Atoms constitute relatively simple many-body systems, making them suitable objects for developing an understanding of basic aspects of many-body physics. Photoabsorption spectroscopy is a prominent method to study the electronic structure of atoms and the inherent many-body interactions. In this article the impact of many-body effects on well-known spectroscopic features such as Rydberg series, Fano resonances, Cooper minima, and giant resonances is studied, and related many-body phenomena in other fields are outlined. To calculate photoabsorption cross sections the time-dependent configuration interaction singles (TDCIS) model is employed. The conceptual clearness of TDCIS in combination with the compactness of atomic systems allows for a pedagogical introduction to many-body phenomena.

Krebs, Dietrich; Santra, Robin

2013-01-01T23:59:59.000Z

426

Determination of Actinide Isotope Ratios Using Glow Discharge Optogalvanic Spectroscopy  

SciTech Connect

Diode-laser excited optogalvanic spectroscopy (OGS) of a glow discharge has been utilized to measure U-235/U-235 + U-238 isotope ratios. This ``optical mass spectrometric`` measurement has been demonstrated for a number of samples including uranium oxide, fluoride, and metal. Various diode-laser accessible atomic transitions in the 775 to 835 nm region have been evaluated; these transitions were chosen by considering OGS sensitivity and isotope shift. Using the 831.84 nm uranium line, for example, it was possible to measure the U-235/U-235 + U-238 isotope ratio (0.0026) of depleted uranium samples. A prototypical field instrument to make these measurements has been assembled and demonstrated. A U-236 spectral line was identified in a sample of enriched uranium, and an abundance sensitivity was measured.

Young, J.P.; Shaw, R.W.; Barshick, C.M.; Ramsey, J.M.

1997-08-01T23:59:59.000Z

427

Direct speciation of metal and metalloid ions by optical spectroscopies  

DOE Green Energy (OSTI)

Molecular level spectroscopic investigations of organic/inorganic interactions provide important new information on sedimentary geochemistry through the identification of interactions over moderate temperature and pH ranges. Although the official title of this project indicates the use of only optical spectroscopies, a combination of Uv/Vis/IR absorption, Raman scattering, and {sup 29}Si and {sup 13}C nuclear magnetic resonance (NMR) experiments are actually employed. A major advantage of integrating spectroscopic results with diagenesis studies is the ability to directly examine the mechanisms of interactions, even in complex matrices and with competing processes. Furthermore, we are extending these techniques to probe fluid inclusions with micro Raman and luminescence techniques to directly compare laboratory results with natural reservoir systems. 25 refs., 4 figs.

Tait, C.D.; Janecky, D.R.; Clark, D.L.; Ekberg, S.A.; Dixon, P.R.; Musgrave, J.A. (Los Alamos National Lab., NM (United States)); Bennett, P.C. (Texas Univ., Austin, TX (United States). Dept. of Geological Sciences)

1991-01-01T23:59:59.000Z

428

Low energy neutral spectroscopy during pulsed discharge cleaning in PLT  

DOE Green Energy (OSTI)

The efflux of neutral hydrogen from PLT during discharge cleaning has been measured using a time-of-flight spectrometer. During high ionization pulsed discharge cleaning (PDC), the flux in the energy range of 5 to 1000 eV varies from 10/sup 14/ H/sup 0//cm/sup 2/xs to 10/sup 16/ H/sup 0//cm/sup 2/xs and the average energy from 10 to 80 eV. The energy distributions are nearly single temperature Maxwellians. Low ionization PDC (Taylor-type) produces a 1000 times lower fluence in the same energy range; however, a flux of 10/sup 16/ H/sup 0//cm/sup 2/xs at energies less than 5 eV is inferred. The detailed submillisecond time variation of these parameters with the fill gas pressure and state of cleanliness of the machine is presented. Comparisons with UV spectroscopy, bolometric measurements, and residual gas analysis are made.

Ruzic, D.; Cohen, S.; Denne, B.; Schivell, J.

1983-04-01T23:59:59.000Z

429

Graphene Thickness Determination Using Reflection and Contrast Spectroscopy  

E-Print Network (OSTI)

We have clearly discriminated the single-, bilayer-, and multiple-layer graphene (graphene sheet. We provide two easy-to-use methods to determine the number of graphene layers based on contrast spectra: a graphic method and an analytical method. We also show that the refractive index of graphene is different from that of graphite. The results are compared with those obtained using Raman spectroscopy. The recent success in extracting graphite sheets in multiple layers, and even monolayer graphene, from highly ordered pyrolytic graphite (HOPG) using a technique called micromechanical cleavage 1,2 has stimulated great interest in both the fundamental physics study and the potential applications of graphene. 3 Graphene has a two-dimensional (2D) crystal structure, which is the basic building block for other sp 2

Z. H. Ni; H. M. Wang; J. Kasim; H. M. Fan; T. Yu; Y. H. Wu; Y. P. Feng; Z. X. Shen

2007-01-01T23:59:59.000Z

430

Experimental Study of Hypernuclei Electroproduction by High Precision Spectroscopy  

SciTech Connect

Jlab experiment E01-011, carried out in 2005 in JLab Hall C, is the second generation of the hypernuclear spectroscopy experiments by the (e,e{prime}K{sup +}) reaction. The (e,e{prime}K{sup +}) reaction is complimentary to the associated production reactions (K{sup -},{pi}{sup -}), ({pi}{sup +},K{sup +}) since, due to a larger momentum transfer to a hyperon, excitations of both spin-non-flip and spin-flip states are possible. The experiment uses high quality and continuous primary electron beam to produce neutron rich hypernuclei on various targets by the electroproduction. The experimental setup consists of splitter magnet, high resolution kaon spectrometer (HKS) and electron spectrometer (Enge) implemented in new configuration, the so called 'Tilt Method'. Production data was taken on multiple targets: CH{sub 2}, {sup 6}Li, {sup 7}Li, {sup 9}Be, {sup 10}B, {sup 12}C and {sup 28}Si. In present study the analysis of CH{sub 2}, {sup 12}C and {sup 28}Si is presented. The elementary processes of p(e,e{prime}K{sup +}){Lambda}/{Sigma} from CH{sup 2} data were used for calibration of the spectrometer optics and kinematics. The hypernuclear spectra of {sup 12}{sub {Lambda}}B was obtained with ground state resolution of 0.47 {+-} 0.07 MeV (FWHM), the best ever achieved. Feasibility of the electroproduction reaction to study medium to heavy targets has been proven with the first high resolution beyond p-shell hypernuclear spectra from {sup 28}{sub {Lambda}}Al hypernuclei. The obtained results of the E01-011 experiment confirmed that hypernuclear spectroscopy by the (e,e{prime}K{sup +}) reaction is a very useful technique.

Tomislav Seva

2009-12-01T23:59:59.000Z

431

Remote monitoring of volcanic gases using passive Fourier transform spectroscopy  

SciTech Connect

Volcanic gases provide important insights on the internal workings of volcanoes and changes in their composition and total flux can warn of impending changes in a volcano`s eruptive state. In addition, volcanoes are important contributors to the earth`s atmosphere, and understanding this volcanic contribution is crucial for unraveling the effect of anthropogenic gases on the global climate. Studies of volcanic gases have long relied upon direct in situ sampling, which requires volcanologists to work on-site within a volcanic crater. In recent years, spectroscopic techniques have increasingly been employed to obtain information on volcanic gases from greater distances and thus at reduced risk. These techniques have included UV correlation spectroscopy (Cospec) for SO{sub 2} monitoring, the most widely-used technique, and infrared spectroscopy in a variety of configurations, both open- and closed-path. Francis et al. have demonstrated good results using the sun as the IR source. This solar occultation technique is quite useful, but puts rather strong restrictions on the location of instrument and is thus best suited to more accessible volcanoes. In order to maximize the flexibility and range of FTIR measurements at volcanoes, work over the last few years has emphasized techniques which utilize the strong radiance contrast between the volcanic gas plume and the sky. The authors have successfully employed these techniques at several volcanoes, including the White Island and Ruapehu volcanoes in New Zealand, the Kilauea volcano on Hawaii, and Mt. Etna in Italy. But Popocatepetl (5452 m), the recently re-awakened volcano 70 km southeast of downtown Mexico City, has provided perhaps the best examples to date of the usefulness of these techniques.

Love, S.P.; Goff, F.; Counce, D.; Schmidt, S.C. [Los Alamos National Lab., NM (United States); Siebe, C.; Delgado, H. [Univ. Nactional Autonoma de Mexico, Coyoacan (Mexico)

1999-06-01T23:59:59.000Z

432

Introduction to NMR Spectroscopy and Physics. C-13 NMR in more detail than "Summary" 83 Chem 355 Jasperse C-13 NMR  

E-Print Network (OSTI)

Introduction to NMR Spectroscopy and Physics. C-13 NMR in more detail than "Summary" 83 Chem 355 Jasperse C-13 NMR I. Introduction to Spectroscopy Spectroscopy involves gaining information from, the most important type of spectroscopy is "NMR" ("Nuclear Magnetic Resonance" spectroscopy). NMR

Jasperse, Craig P.

433

Reflectance Vis/NIR spectroscopy for nondestructive taste characterization of Valencia oranges  

Science Conference Proceedings (OSTI)

The feasibility of reflectance Vis/NIR spectroscopy was investigated for taste characterization of Valencia oranges based on taste attributes including soluble solids content (SSC) and titratable acidity (TA), as well as taste indices including SSC to ... Keywords: BrimA, Nondestructive, Taste, Valencia orange, Vis/NIR spectroscopy

Bahareh Jamshidi; Saeid Minaei; Ezzedin Mohajerani; Hassan Ghassemian

2012-07-01T23:59:59.000Z

434

Measurement of uranium enrichment by gamma spectroscopy: result of an experimental design  

E-Print Network (OSTI)

PAPER Measurement of uranium enrichment by gamma spectroscopy: result of an experimental design Gamma spectroscopy is commonly used in nuclear safeguards to measure uranium enrichment. An experimental design has been carried out for the measurement of uranium enrichment using this technique with different

435

Absorption spectroscopy in hollow-glass waveguides using infrared laser diodes  

Science Conference Proceedings (OSTI)

Hollow-glass waveguides may be a viable technology that, in some cases, may supplant heavier multi-pass cells such as White or Herriott cells for performing trace detection using tunable diode laser absorption spectroscopy. We report here a series of experiments for testing the suitability of waveguides for infrared spectroscopy. The loss characteristics of 1 mm bore diameter waveguides have been measured for straight and coiled lengths. Using direct absorption spectroscopy we have found that the absorption pathlength is approximately equal to the physical length of the waveguide. Broadband FM diode laser spectroscopy produces a comparable signal-to-noise ratio with less than a second of signal averaging. Finally, we have also performed near-infrared spectroscopy of nitrous oxide flowing through a waveguide using a telecommunications diode laser.

Blake, Thomas A.; Kelly, James F.; Stewart, Timothy L.; Hartman, John S.; Sharpe, Steven W.; Sams, Robert L.

2002-07-10T23:59:59.000Z

436

Revised Version DESY04128 arXiv:physics/0408137  

E-Print Network (OSTI)

of flexible molecules in this intermediate size regime.6 The method has been applied first to the methyl using the methods of IR-UV hole-filling spectroscopy HFS and IR-induced population transfer spectroscopy. These changes in population were detected using laser-induced fluorescence downstream in the expansion. In HFS

437

Cone Penetrometer for Subsurface Heavy Metals Detection. Semiannual report, November 1, 1996--March 31, 1997  

Science Conference Proceedings (OSTI)

Surface and subsurface contamination of soils by heavy metals, including Pb, Cr, Cu, Zn, and Cd, has become an area of concern for many industrial and government organizations (1). Conventional sampling and analysis techniques for soil provide a high degree of sensitivity and selectivity for individual analytes. However, obtaining a representative sampling and analysis from a particular site using conventional techniques is time consuming and costly (2). Additionally, conventional methods are difficult to implement in the field for in situ and/or real-time applications. Therefore, there is a need for characterization and monitoring techniques for heavy metals in soils which allow cost-effective, rapid, in situ measurements. Laser-induced breakdown spectroscopy (LIBS) has been used to successfully measure metals content in a variety of matrices (3-15) including soil (16,17). Under the Department of Energy (DOE) Federal Energy Technology Center (FETC) Industry Program, Science {ampersand} Engineering Associates (SEA) is developing a subsurface cone penetrometer (CPT) probe for heavy metals detection that employs LIBS (18). The LIES-CPT unit is to be applied to in situ, real-time sampling and analysis of heavy metals in soil. As part of its contract with DOE FETC, SEA is scheduled to field test its LIBS-CPT system in September 1997.

Grisanti, Ames A.; Timpe, Ronald C.; Foster, H.J.; Eylands, Kurt E.; Crocker, Charlene R.

1997-12-31T23:59:59.000Z

438

In-Situ Real Time Measurements of Molten Glass Properties, Final Report  

SciTech Connect

Energy Research Company (ERCo) of Staten Island, NY has developed a sensor capable of measuring in situ and in real time, both the elemental composition and the temperature of molten glass. A prototype sensor has been designed, constructed and tested in ERCo's laboratory. The sensor was used to collect atomic emission spectra from molten fiberglass via Laser Induced Breakdown Spectroscopy (LIBS). From these spectra, we were able to readily identify all elements of interest (B, Si, Ca, Fe, Mg, Na, Sr, Al). The high signal-to-background signals achieved suggest that data from the sensor can be used to determine elemental concentrations, either through calibration curves or using ERCo's calibrationless method. ERCo's technology fits in well with DOE's Glass Industry Technology Roadmap which emphasizes the need for accurate process and feedstock sensors. Listed first under technological barriers to increased production efficiency is the 'Inability to accurately measure and control the production process'. A large-scale glass melting furnace, developed by SenCer Inc. of Penn Yan, NY was installed in ERCo's laboratory to ensure that a large enough quantity of glass could be melted and held at temperature in the presence of the water-cooled laser sensor without solidifying the glass.

Robert De Saro; Joe Craparo

2007-12-16T23:59:59.000Z

439

Experimental and computational study of complex shockwave dynamics in laser ablation plumes in argon atmosphere  

SciTech Connect

We investigated spatio-temporal evolution of ns laser ablation plumes at atmospheric pressure, a favored condition for laser-induced breakdown spectroscopy and laser-ablation inductively coupled plasma mass-spectrometry. The 1064 nm, 6 ns pulses from a Nd:YAG laser were focused on to an Al target and the generated plasma was allowed to expand in 1 atm Ar. The hydrodynamic expansion features were studied using focused shadowgraphy and gated 2 ns self-emission visible imaging. Shadowgram images showed material ejection and generation of shock fronts. A secondary shock is observed behind the primary shock during the time window of 100-500 ns with instabilities near the laser cone angle. By comparing the self-emission images obtained using fast photography, it is concluded that the secondary shocks observed in the shadowgraphy were generated by fast moving target material. The plume front estimates using fast photography exhibited reasonable agreement with data obtained from shadowgraphy at early times {<=}400 ns. However, at later times, fast photography images showed plume confinement while the shadowgraphic images showed propagation of the plume front even at greater times. The structure and dynamics of the plume obtained from optical diagnostic tools were compared to numerical simulations. We have shown that the main features of plume expansion in ambient Ar observed in the experiments can be reproduced using a continuum hydrodynamics model which provided valuable insight into the expansion dynamics and shock structure of the plasma plume.

Harilal, S. S.; Miloshevsky, G. V.; Diwakar, P. K.; LaHaye, N. L.; Hassanein, A. [Center for Materials under Extreme Environment, and School of Nuclear Engineering, Purdue University, West Lafayette, Indiana 47907 (United States)

2012-08-15T23:59:59.000Z

440

EM Task 13 -- Cone penetrometer for subsurface heavy metals detection. Semi-annual report, April 1--September 30, 1997  

SciTech Connect

Surface and subsurface contamination of soils by heavy metals, including Pb, Cr, Cu, Zn, and Cd has become an area of concern for many industrial and government organizations. Conventional sampling and analysis techniques for soil provide a high degree of sensitivity and selectivity for individual analytes. However, obtaining a representative sampling and analysis from a particular site using conventional techniques is time-consuming and costly. Additionally, conventional methods are difficult to implement in the field for in situ and/or real-time applications. Therefore, there is a need for characterization and monitoring techniques for heavy metals in soils which allow cost-effective, rapid, in situ measurements. Laser induced breakdown spectroscopy (LIBS) has been used to successfully measure metals content in a variety of matrices including soil. Science and Engineering Associates (SEA) is developing a subsurface cone penetrometer (CPT) probe for heavy metal detection that employs LIBS. The LIBS/CPT unit is to be applied to in situ, real-time sampling and analysis of heavy metals in soil. The overall objectives of this project are to evaluate potential calibration techniques for the LIBS/CPT instrument and to provide a preliminary evaluation of the LIBS instrument calibration using samples obtained from the field.

Grisanti, A.A.; Timpe, R.C.; Foster, H.J.; Eylands, K.E.; Crocker, C.R.

1997-12-31T23:59:59.000Z

Note: This page contains sample records for the topic "laser-induced breakdown spectroscopy" from the National Library of EnergyBeta (NLEBeta).
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to obtain the most current and comprehensive results.


441

Summary report of FY 1995 Raman spectroscopy technology development  

Science Conference Proceedings (OSTI)

US DOE is sponsoring development of remote, fiber-optic Raman spectroscopy for rapid chemical characterization of Hanford high-level radioactive tank waste. Deployment targets for this technology are analytical hot cells and, via the Light-Duty Utility Arm and cone penetrometer, the waste tanks themselves. Perceived benefits of fiber-optic Raman spectroscopy are (1) rapid generation of tank-waste safety-related data, (2) reduced personnel exposure to highly radioactive waste, (3) reduced tank-waste sampling and analysis costs, and (4) reduced radioactive analytical waste. This document presents the results from the investigation of two dispersive, transmission-grating Raman systems and four fiber-optic Raman probe designs with non-radioactive tank waste simulants. One Raman system used a 532-nm, 400 mW, solid-state laser; the other used a 785-nm, 500 mW, solid-state diode laser. We found (1) the transmission-grating systems had better wavelength stability than previously tried Czerny-Turner-Based systems and (2) the 785-nm system`s specie detection limits in the spectral fingerprint regiion were at least as good as those for the 532-nm system. Based on these results, and the fact that some tank wastes luminesce with 514.5nm excitation, we selected the 785-nm system for hot-cell use. Of the four probes tested, three had a ``six-around-on`` fiber probe design; the fourth probe was a one-fiber-in-one-fiber-out, diffuse-relectance design. Comparison of the four probes` signal-to-noise rations, rations, transmission/collection efficiencies, and probe-silica Raman backgrounds showed that the best probe for use with Hanford-Site tank waste should (1) be filtered as close to the probe tip as possible to reduce the probe-silica Raman background and (2) have multiple collection fibers. The responses of all the probes tested showed a strong dependence on probe-sample distance, and the presence of a probe window appeared to increase the probe`s silica Raman background.

Douglas, J.G.

1995-11-01T23:59:59.000Z

442

Assaying protein import into mitochondria using fluorescence spectroscopy  

E-Print Network (OSTI)

Most proteins residing in the mitochondrial matrix are synthesized in the cytosol and post-translationally imported into the mitochondrial matrix. The matrix-targeted preproteins traverse the outer mitochondrial membrane (OM) via the Translocase of the Outer Membrane (TOM) complex, and the inner mitochondrial membrane (IM) via the Translocase of the Inner Membrane 23 (TIM23) complex. A novel system was set up to examine the import of matrix-targeted preproteins into mitochondria using fluorescence spectroscopy. The fluorescent probe 6-(7-nitrobenz-2-oxa-1,3-diazol-4- yl)aminohexanoic acid (NBD) was site-specifically incorporated into different positions along the model matrix protein Su9-DHFR. The fluorescent-labeled polypeptides were either fully imported into isolated mitochondria or were arrested along the translocation pathway by the binding of methotrexate (MTX) to the DHFR moiety, creating NBDSu9- DHFRÂ?MTX import intermediates. The NBD-Su9-DHFR polypeptides were able to be fully imported into the mitochondrial matrix in the absence of MTX, and were inaccessible to externally-added iodide ion quenchers. Treatment of the mitochondria with the pore-forming antibiotic alamethicin allowed the iodide ion quenchers access to the matrix through pores in the inner membrane (IM). After Alamethicin treatment the fully-imported NBD-Su9-DHFR polypeptides were accessible to the externally-added iodide ions. The extent of collisional quenching of the NBD fluorophores by the iodide ions was measured as the Stern-Volmer quenching constant, Ksv. Ksv values were obtained for the NBD-Su9-DHFR polypeptides in the presence of MTX (import intermediates) or in the absence of MTX (fully-imported). The Ksv values for NBD-Su9- DHFR import intermediates were similar, despite the location of the NBD probe along the translocation pathway. These Ksv values were similar to those obtained for the fullyimported NBD-Su9-DHFR polypeptides (-MTX). The locations of the varying probe positions along the import pathway were addressed using chemical crosslinking of Su9- DHFR Cys mutants. The use of fluorescence spectroscopy, in association with chemical crosslinking, to analyze the mitochondrial protein import pathways will prove a useful tool to probe the environment of the nascent chain as it is crossing the import pathway (the TOM, TIM23 complexes).

Cargill, Holly Beth

2003-05-01T23:59:59.000Z

443

Method of using a nuclear magnetic resonance spectroscopy standard  

DOE Patents (OSTI)

(CH.sub.3).sub.3 SiNSO is produced by the reaction of ((CH.sub.3).sub.3 Si).sub.2 NH with SO.sub.2. Also produced in the reaction are ((CH.sub.3).sub.3 Si).sub.2 O and a new solid compound [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ]. Both (CH.sub.3).sub.3 SiNSO and [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] have fluorescent properties. The reaction of the subject invention is used in a method of measuring the concentration of SO.sub.2 pollutants in gases. By the method, a sample of gas is bubbled through a solution of ((CH.sub.3).sub.3 Si).sub.2 NH, whereby any SO.sub.2 present in the gas will react to produce the two fluorescent products. The measured fluorescence of these products can then be used to calculate the concentration of SO.sub.2 in the original gas sample. The solid product [NH.sub.4 ][(CH.sub.3).sub.3 SiOSO.sub.2 ] may be used as a standard in solid state NMR spectroscopy, wherein the resonance peaks of either .sup.1 H, .sup.13 C, .sup.15 N, or .sup.29 Si may be used as a reference.

Spicer, Leonard D. (Salt Lake City, UT); Bennett, Dennis W. (Clemson, SC); Davis, Jon F. (Salt Lake City, UT)

1985-01-01T23:59:59.000Z

444

Surface enhanced Raman spectroscopy for microfluidic pillar arrayed separation chips  

SciTech Connect

Numerous studies have addressed the challenges of implementing miniaturized microfluidic platforms for chemical and biological separation applications. However, the integration of real time detection schemes capable of providing valuable sample information under continuous, ultra low volume flow regimes has not fully been addressed. In this report we present a chip based chromatography system comprising of a pillar array separation column followed by a reagent channel for passive mixing of a silver colloidal solution into the eluent stream to enable surface enhanced Raman spectroscopy (SERS) detection. Our design is the first integrated chip based microfluidic device to combine pressure driven separation capability with real time SERS detection. With this approach we demonstrate the ability to collect distinctive SERS spectra with or without complete resolution of chromatographic bands. Computational fluidic dynamic (CFD) simulations are used to model the diffusive mixing behavior and velocity profiles of the two confluent streams in the microfluidic channels. We evaluate the SERS spectral band intensity and chromatographic efficiency of model analytes with respect to kinetic factors as well as signal acquisition rates. Additionally, we discuss the use of a pluronic modified silver colloidal solution as a means of eliminating contamination generally caused by nanoparticle adhesion to channel surfaces.

Taylor, Lisa [University of Tennessee, Knoxville (UTK); Kirchner, Teresa B [ORNL; Lavrik, Nickolay V [ORNL; Sepaniak, Michael [University of Tennessee, Knoxville (UTK)

2012-01-01T23:59:59.000Z

445

Visible spectroscopy in the DIII-D divertor  

SciTech Connect

Spectroscopy measurements in the DIII-D divertor have been carried out with a survey spectrometer which provides simultaneous registration of the visible spectrum over the region 400--900 nm with a resolution of 0.2 nm. Broad spectral coverage is achieved through use of a fiberoptic transformer assembly to map the curved focal plane of a fast (f/3) Rowland-circle spectrograph into a rastered format on the rectangular sensor area of a two-dimensional CCD camera. Vertical grouping of pixels during CCD readout integrates the signal intensity over the height of each spectral segment in the rastered image, minimizing readout time. For the full visible spectrum, readout time is 50 ms. Faster response time (< 10 ms) may be obtained by selecting for readout just a small number of the twenty spectral segments in the image on the CCD. Simultaneous recording of low charge states of carbon, oxygen and injected impurities has yielded information about gas recycling and impurity behavior at the divertor strike points. Transport of lithium to the divertor region during lithium pellet injection has been studied, as well as cumulative deposition of lithium on the divertor targets from pellet injection over many successive discharges.

Brooks, N.H. [General Atomics, San Diego, CA (United States); Fehling, D.; Hillis, D.L.; Klepper, C.C. [Oak Ridge National Lab., TN (United States); Naumenko, N. [Inst. of Physics, Minsk (Belarus); Tugarinov, S. [TRINITI Lab., Troitsk (Russian Federation); Whyte, D.G. [INRS-Energie et Materiaux, Varennes, Quebec (Canada)

1996-06-01T23:59:59.000Z

446

Single-molecule force spectroscopy: Practical limitations beyond Bell's model  

E-Print Network (OSTI)

Single-molecule force spectroscopy experiments, as well as a number of other physical systems, are governed by thermally activated transitions out of a metastable state under the action of a steadily increasing external force. The main observable in such experiments is the distribution of the forces, at which the escape events occur. The challenge in interpreting the experimental data is to relate them to the microscopic system properties. We work out a maximum likelihood approach and show that it is the optimal method to tackle this problem. When fitting actual experimental data it is unavoidable to assume some functional form for the force-dependent escape rate. We consider a quite general and common such functional form and demonstrate by means of data from a realistic computer experiment that the maximum number of fit parameters that can be determined reliably is three. They are related to the force-free escape rate and the position and height of the activation barrier. Furthermore, the results for the first two of these fit parameters show little dependence on the assumption about the manner in which the barrier decreases with the applied force, while the last one, the barrier height in the absence of force, depends strongly on this assumption.

Sebastian Getfert; Mykhaylo Evstigneev; Peter Reimann

2008-05-19T23:59:59.000Z

447

Simulated X-Ray Absorption Spectroscopy on the Water Dimer  

DOE Green Energy (OSTI)

The ability of an individual H{sub 2}O molecule to form multiple hydrogen bonds with neighboring molecules makes it an ideal substance for the study of hydrogen bonding. X-ray absorption spectroscopy (XAS) can be used to study what intermolecular structur