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1

Simulations Identify Requirements for LANL's High Intensity Laser...  

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

Identify Requirements for LANL's High Intensity Laser Lab cielo equip Fig. 1. Cielo is a 1.37 petaflops capability-class supercomputer installed at LANL, funded by the US DOE NNSA...

2

Slow Electrons Generated by Intense High-Frequency Laser Pulses  

Science Conference Proceedings (OSTI)

A very slow electron is shown to emerge when an intense high-frequency laser pulse is applied to a hydrogen negative ion. This counterintuitive effect cannot be accounted for by multiphoton or tunneling ionization mechanisms. We explore the effect and show that in the high-frequency regime the atomic electron is promoted to the continuum via a nonadiabatic transition caused by slow deformation of the dressed potential that follows a variation of the envelope of the laser pulse. This is a general mechanism, and a slow electron peak should always appear in the photoelectron spectrum when an atom is irradiated by a high-frequency pulse of finite length.

Toyota, Koudai; Watanabe, Shinichi [Department of Applied Physics and Chemistry, University of Electro-Communications, 1-5-1, Chofu-ga-oka, Chofu-shi, Tokyo (Japan); Tolstikhin, Oleg I. [Russian Research Center 'Kurchatov Institute', Kurchatov Square 1, Moscow 123182 (Russian Federation); Morishita, Toru [Department of Applied Physics and Chemistry, University of Electro-Communications, 1-5-1, Chofu-ga-oka, Chofu-shi, Tokyo (Japan); PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan)

2009-10-09T23:59:59.000Z

3

Frequency conversion of high-intensity, femtosecond laser pulses  

SciTech Connect

Almost since the invention of the laser, frequency conversion of optical pulses via non- linear processes has been an area of active interest. However, third harmonic generation using ~(~1 (THG) in solids is an area that has not received much attention because of ma- terial damage limits. Recently, the short, high-intensity pulses possible with chirped-pulse amplification (CPA) laser systems allow the use of intensities on the order of 1 TW/cm2 in thin solids without damage. As a light source to examine single-crystal THG in solids and other high field inter- actions, the design and construction of a Ti:sapphire-based CPA laser system capable of ultimately producing peak powers of 100 TW is presented. Of special interest is a novel, all-reflective pulse stretcher design which can stretch a pulse temporally by a factor of 20,000. The stretcher design can also compensate for the added material dispersion due to propagation through the amplifier chain and produce transform-limited 45 fs pulses upon compression. A series of laser-pumped amplifiers brings the peak power up to the terawatt level at 10 Hz, and the design calls for additional amplifiers to bring the power level to the 100 TW level for single shot operation. The theory for frequency conversion of these short pulses is presented, focusing on conversion to the third harmonic in single crystals of BBO, KD*P, and d-LAP (deuterated I-arginine phosphate). Conversion efficiencies of up to 6% are obtained with 500 fs pulses at 1053 nm in a 3 mm thick BBO crystal at 200 GW/cm 2. Contributions to this process by unphasematched, cascaded second harmonic generation and sum frequency generation are shown to be very significant. The angular relationship between the two orders is used to measure the tensor elements of C = xt3)/4 with Crs = -1.8 x 1O-23 m2/V2 and .15Cri + .54Crs = 4.0 x 1O-23 m2/V2. Conversion efficiency in d-LAP is about 20% that in BBO and conversion efficiency in KD*P is 1% that of BBO. It is calculated that conversion efficiencies of 30-40% are possible at intensities of 600-800 GW/cm2, which is the operating level of the Petawatt laser at LLNL. The main limiting factors are phase modulation and material damage.

Banks, P S

1997-06-01T23:59:59.000Z

4

High-Intensity Laser Diagnostics for OMEGA EP  

Science Conference Proceedings (OSTI)

OMEGA EP is a new high-energy petawatt laser system under construction at the University of Rochester’s Laboratory for Laser Energetics. This paper describes our designs for two diagnostics critical to OMEGA EP’s mission. The focal-spot diagnostic (FSD) is responsible for characterizing the focal spot of OMEGA EP’s off-axis parabolic mirror at full energy. The ultrafast temporal diagnostic (UTD) is responsible for characterizing pulse shapes of full-energy target shots ranging in width from petawatt laser at full energy.

Bromage, J.; Zuegel, J.D.; Bahk, S.-W.; Vickery, D.S.; Waxer, L.J.; Irwin, D.; Bagnoud, V.; Boni, R.; Moore, M.D.; Junquist, R.; Stoeckl, C.

2006-07-13T23:59:59.000Z

5

High-order harmonics from bow wave caustics driven by a high-intensity laser  

Science Conference Proceedings (OSTI)

We propose a new mechanism of high-order harmonic generation during an interaction of a high-intensity laser pulse with underdense plasma. A tightly focused laser pulse creates a cavity in plasma pushing electrons aside and exciting the wake wave and the bow wave. At the joint of the cavity wall and the bow wave boundary, an annular spike of electron density is formed. This spike surrounds the cavity and moves together with the laser pulse. Collective motion of electrons in the spike driven by the laser field generates high-order harmonics. A strong localization of the electron spike, its robustness to oscillations imposed by the laser field and, consequently, its ability to produce high-order harmonics is explained by catastrophe theory. The proposed mechanism explains the experimental observations of high-order harmonics with the 9 TW J-KAREN laser (JAEA, Japan) and the 120 TW Astra Gemini laser (CLF RAL, UK) [A. S. Pirozhkov, et al., arXiv:1004.4514 (2010); A. S. Pirozhkov et al, AIP Proceedings, this volume]. The theory is corroborated by high-resolution two-and three-dimensional particle-in-cell simulations.

Pirozhkov, A.S.; Kando, M.; Esirkepov, T.Zh. [Advanced Beam Technology Division, Japan Atomic Energy Agency (Japan); and others

2012-07-11T23:59:59.000Z

6

ANALYSIS AND MITIGATION OF X-RAY HAZARD GENERATED FROM HIGH INTENSITY LASER-TARGET INTERACTIONS  

SciTech Connect

Interaction of a high intensity laser with matter may generate an ionizing radiation hazard. Very limited studies have been made, however, on the laser-induced radiation protection issue. This work reviews available literature on the physics and characteristics of laser-induced X-ray hazards. Important aspects include the laser-to-electron energy conversion efficiency, electron angular distribution, electron energy spectrum and effective temperature, and bremsstrahlung production of X-rays in the target. The possible X-ray dose rates for several femtosecond Ti:sapphire laser systems used at SLAC, including the short pulse laser system for the Matter in Extreme Conditions Instrument (peak power 4 TW and peak intensity 2.4 x 10{sup 18} W/cm{sup 2}) were analysed. A graded approach to mitigate the laser-induced X-ray hazard with a combination of engineered and administrative controls is also proposed.

Qiu, Rui

2011-03-21T23:59:59.000Z

7

The Edward teller medal lecture: High intensity lasers and the road to ignition  

SciTech Connect

There has been much progress in the development of high intensity lasers and in the science of laser driven inertially confined fusion such that ignition is now a near term prospect. This lecture reviews the field with particular emphasis on areas of my own involvement. {copyright} {ital 1997 American Institute of Physics.}

Key, M.H. [Lawrence Livermore National Laboratory, Livermore, California94551 (United States)

1997-04-01T23:59:59.000Z

8

The Edward Teller medal lecture: High intensity lasers and the road to ignition  

SciTech Connect

There has been much progress in the development of high intensity lasers and in the science of laser driven inertially confined fusion such that ignition is now a near term prospect. This lecture reviews the field with particular emphasis on areas of my own involvement.

Key, M. H. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

1997-04-15T23:59:59.000Z

9

Edward Teller medal lecture: high intensity lasers and the road to ignition  

SciTech Connect

There has been much progress in the development of high intensity lasers and in the science of laser driven inertially confined fusion such that ignition is now a near term prospect. This lecture reviews the field with particular emphasis on areas of my own involvement.

Key, M.H.

1997-06-02T23:59:59.000Z

10

A Plasma Lens for High Intensity Laser Focusing  

SciTech Connect

A plasma lens based on a short hydrogen-filled alumina capillary discharge is experimentally characterized. For a plasma length of about 5mm, the focal length, measured from the plasma entrance, was {approx} 11 to 8mm for on axis densities of {approx} 2.5 to 5 x 1018cm-3, respectively. The plasma temperature away from the walls of the 1/2mm diameter capillary was estimated to be {approx} 8eV indicating that the plasma is fully ionized. Such a lens should thus be suitable for focusing very high intensity pulses. Comparisons of the measured focusing strength to that predicted by a first-order fluid model [N. A. Bobrova, et al., Phys. Rev. E 65, 016407 (2002)] shows reasonable agreement given that some of the observed plasma parameters are not predicted by this model.

Fang, F.; Clayton, C. E.; Marsh, K. A.; Joshi, C. [UCLA Department of Electrical Engineering, Los Angeles, CA, 90095 (United States); Lopes, N. C. [Grupo de Lasers e Plasmas, ESuperior Tecnico, Lisbon (Portugal); Ito, H. [Utsunomiya University, 7-1-2 Yoto, Utsunomiya City, Zip 321-8585 (Japan)

2006-11-27T23:59:59.000Z

11

Dynamical Schwinger effect and high-intensity lasers. Realising nonperturbative QED.  

Science Conference Proceedings (OSTI)

We consider the possibility of experimental verification of vacuum e{sup +}e{sup -} pair creation at the focus of two counter-propagating optical laser beams with intensities 10{sup 20}-10{sup 22} W/cm{sup 2}, achievable with present-day petawatt lasers, and approaching the Schwinger limit: 10{sup 29} W/cm{sup 2} to be reached at ELI. Our approach is based on the collisionless kinetic equation for the evolution of the e{sup +} and e{sup -} distribution functions governed by a non-Markovian source term for pair production. As possible experimental signals of vacuum pair production we consider e{sup +}e{sup -} annihilation into {gamma}-pairs and the refraction of a high-frequency probe laser beam by the produced e{sup +}e{sup -} plasma. We discuss the dependence of the dynamical pair production process on laser wavelength, with special emphasis on applications in the X-ray domain (X-FEL), as well as the prospects for {mu}{sup +}{mu}{sup -} and {pi}{sup +}{pi}{sup -} pair creation at high-intensity lasers. We investigate perspectives for using high-intensity lasers as 'boosters' of ion beams in the few-GeV per nucleon range, which is relevant, e.g., to the exploration of the QCD phase transition in laboratory experiments.

Blaschke, D. B.; Prozorkevich, A. V.; Roepke, G.; Roberts, C. D.; Schmidt, S. M.; Shkirmanov, D. S.; Smolyansky, S. A.; Physics; Univ. of Wroclaw; Joint Inst. for Nuclear Research; Univ. Rostock; Saratov State Univ.; Forschungszentrum Juelich GmbH

2009-11-01T23:59:59.000Z

12

Dynamical Schwinger effect and high-intensity lasers. Realising nonperturbative QED  

E-Print Network (OSTI)

We consider the possibility of experimental verification of vacuum e^+e^- pair creation at the focus of two counter-propagating optical laser beams with intensities 10^{20}-10^{22} W/cm^2, achievable with present-day petawatt lasers, and approaching the Schwinger limit: 10^{29} W/cm^2 to be reached at ELI. Our approach is based on the collisionless kinetic equation for the evolution of the e^+ and e^- distribution functions governed by a non-Markovian source term for pair production. As possible experimental signals of vacuum pair production we consider e^+e^- annihilation into gamma-pairs and the refraction of a high-frequency probe laser beam by the produced e^+e^- plasma. We discuss the dependence of the dynamical pair production process on laser wavelength, with special emphasis on applications in the X-ray domain (X-FEL), as well as the prospects for \\mu^+\\mu^- and \\pi^+\\pi^- pair creation at high-intensity lasers. We investigate perspectives for using high-intensity lasers as ``boosters'' of ion beams in the few-GeV per nucleon range, which is relevant, e.g., to the exploration of the QCD phase transition in laboratory experiments.

D. B. Blaschke; A. V. Prozorkevich; G. Roepke; C. D. Roberts; S. M. Schmidt; D. S. Shkirmanov; S. A. Smolyansky

2008-11-21T23:59:59.000Z

13

Time Integrated Soft X-ray Imaging in High Intensity Laser Experiments (thesis)  

Science Conference Proceedings (OSTI)

2009 marks a significant achievement and the dawn of a new era in high intensity laser research with the final commissioning of all 192 beams at the National Ignition Facility (NIF). NIF is a department of energy (DOE) funded project more than 10 years in the making located at the Lawrence Livermore National Laboratory (LLNL). The following research was done as one of many preliminary experiments done to prepare for these historic events. The primary focus of the experimental campaign this paper addresses is to test and develop a thermal x-radiation source using a short pulse laser. This data is hoped to provide information about the thermal transport mechanisms important in the development of prediction models in High Energy Density (HED) science. One of several diagnostics fielded was a soft x-ray imager (SXRI) which is detailed in this paper. The SXRI will be used to measure the relative size of the heated region and also the relative level of specific x-ray emissions among several shot and target configurations. The laser system used was the Titan laser located in the Jupiter Laser Facility (JLF) at Lawrence Livermore National Laboratory (LLNL). Titan uses the JLF Janus Nd:glass laser west frontend system with a Optical Parametric Chirped Pulse Amplification (OPCPA) in place of the nanosecond oscillator. The system is capable of producing laser intensities of over a petawatt with several tens of joules delivered in the beam.

Stafford, D

2009-06-01T23:59:59.000Z

14

Guiding of high intensity ultrashort laser pulses in plasma channels produced with the dual laser pulse ignitor-heater technique  

DOE Green Energy (OSTI)

The authors present results of experimental investigations of laser guiding in plasma channels. A new technique for plasma channel creation, the Ignitor-Heater scheme is proposed and experimentally tested in hydrogen and nitrogen. It makes use of two laser pulses. The Ignitor, an ultrashort (< 100 fs) laser pulse, is brought to a line focus using a cylindrical lens to ionize the gas. The Heater pulse (160 ps long) is used subsequently to heat the existing spark via inverse Bremsstrahlung. The hydrodynamic shock expansion creates a partially evacuated plasma channel with a density minimum on axis. Such a channel has properties of an optical waveguide. This technique allows creation of plasma channels in low atomic number gases, such as hydrogen, which is of importance for guiding of highly intense laser pulses. The channel density was diagnosed with time resolved longitudinal interferometry. From these measurements the plasma temperature was inferred. The guiding properties of the channels were tested by injecting a > 5 {times} 10{sup 17} W/cm{sup 2}, 75 fs laser pulse.

Volfbeyn, P.; Leemans, W.P.

1998-07-01T23:59:59.000Z

15

Nonlinear reflection of high intensity picosecond laser pulse from overdense plasma  

Science Conference Proceedings (OSTI)

The interaction of 1.5 ps FWHM laser pulses with solid targets at intensity 10{sup 15}-10{sup 17} W/cm{sup 2} and contrast ratio 10{sup 6} is studied. Red shift of a 'mirror' reflected fundamental wave and its second harmonic depending on the incident laser pulse energy and angle of incidence are observed. They are associated with Doppler shift corresponding to inward movement of the critical density surface from laser pondermotive pressure. Back scattered light has nonlinear dependence from laser intensity connected with SBS and changing of plasma surface.

Andreev, A. A.; Bayanov, V. I.; Vankov, A. B.; Kozlov, A. A.; Kurnin, I. V.; Platonov, K. Y.; Solovyev, N. A.; Chizhov, S. A.; Yashin, V. E. [Research Institute for Laser Physics, SC 'Vavilov State Optical Institute', 12, Birzhevaya line, St. Petersburg, 199034 (Russian Federation)

1998-02-20T23:59:59.000Z

16

Nonlinear reflection of high intensity picosecond laser pulse from overdense plasma  

Science Conference Proceedings (OSTI)

The interaction of 1.5 ps FWHM laser pulses with solid targets at intensity 10 15 –10 17 ? W/cm 2 and contrast ratio 10 6 is studied. Red shift of a “mirror” reflected fundamental wave and its second harmonic depending on the incident laser pulse energy and angle of incidence are observed. They are associated with Doppler shift corresponding to inward movement of the critical density surface from laser pondermotive pressure. Back scattered light has nonlinear dependence from laser intensity connected with SBS and changing of plasma surface.

A. A. Andreev; V. I. Bayanov; A. B. Vankov; A. A. Kozlov; I. V. Kurnin; K. Y. Platonov; N. A. Solovyev; S. A. Chizhov; V. E. Yashin

1998-01-01T23:59:59.000Z

17

Development and applications of compact high-intensity lasers* G. Mourou+ and D. Umstadter  

E-Print Network (OSTI)

'ttnt*t' ' 't**Bd ' 'r'"& lOi 10'4 lOiS lo'! 10" Laser intensity (W/cm') 1 oio :0 109 z g lo8 3 N `ij 10

Umstadter, Donald

18

Narrow Energy Spread Protons and Ions from High-Intensity, High-Contrast Laser Solid Target Interactions  

Science Conference Proceedings (OSTI)

Recent simulations show that an idealized, high intensity, short pulse laser can generate quasi-monoenergetic proton beams with energies over 100 MeV in an interaction with a thin film. However, most short pulse laser facilities with sufficient intensity have difficulty controlling the nanosecond and picosecond contrast necessary to realize such a regime. Experiments were performed to investigate proton and ion acceleration from a high contrast, short pulse laser by employing dual plasma mirrors along with a deformable mirror at the HERCULES laser facility at the Center for Ultrafast Optical Sciences, University of Michigan. Plasma mirrors were characterized, allowing a 50% throughput with an intensity contrast increase of 105. The focal spot quality was also exceptional, showing a 1.1 micron full width at half maximum (FWHM) focal diameter. Experiments were done using temporally cleaned 30 TW, 32 fs pulses to achieve an intensity of up to 10{sup 21} Wcm{sup -2} on Si{sub 3}N{sub 4} and Mylar targets with thicknesses ranging 50 nm to 13 microns. Proton beams with energy spreads below 2 MeV were observed from all thicknesses, peaking with energies up to 10.3 MeV and an energy spread of 0.8 MeV. Similar narrow energy spreads were observed for oxygen, nitrogen, and carbon at the silicon nitride thickness of 50 nm with energies up to 24 MeV with an energy spread of 3 MeV, whereas the energy spread is greatly increased at a larger thickness. Maximum energies were confirmed with CR39 track detectors, while a Thomson ion spectrometer was used to gauge the monoenergetic nature of the beam.

Dollar, Franklin; Matsuoka, Takeshi; McGuffey, Christopher; Bulanov, Stepan S.; Chvykov, Vladimir; Kalintchenko, Galina; Thomas, Alec G. R.; Willingale, Louise; Yanovsky, Victor; Maksimchuk, Anatoly; Krushelnick, Karl [Center for Ultrafast Optical Science, Univ. Of Michigan, Ann Arbor, MI 48109 (United States); Davis, Jack; Petrov, George [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)

2010-11-04T23:59:59.000Z

19

Design of a high-intensity RFQ for a possible LHC laser ion source  

E-Print Network (OSTI)

We have designed a 100 MHz RFQ to accelerate Pb25+ ions from 9.6 keV/u to 250 keV/u for the LHC ion program. We assume an input beam from a laser ion source with a total beam current of 90 mA, out of which 9 mA is Pb25+. The main challenge of the design is to match the tight longitudinal acceptance of the downstream Interdigital H structure while dealing with a high intensity beam composed of a variety of charge states. In this paper, we present a baseline setup optimized for nominal conditions, and show the sensitivity of the RFQ performance to varying input beam characteristics and rf parameters. Further studies will cover the compatibility of this design with an upgraded ECR source under investigation at CERN.

Hanke, K

2002-01-01T23:59:59.000Z

20

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

Note: This page contains sample records for the topic "high intensity laser" 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

Sensitivity to Dark Energy candidates by searching for four-wave mixing of high-intensity lasers in the vacuum  

E-Print Network (OSTI)

Theoretical challenges to understand Dark Matter and Dark Energy suggest the existence of low-mass and weakly coupling fields in the universe. The quasi-parallel photon-photon collision system (QPS) can provide chances to probe the resonant production of these light dark fields and the induced decay by the coherent nature of laser fields simultaneously. By focusing high-intensity lasers with different colors in the vacuum, new colors emerge as the signature of the interaction. Because four photons in the initial and final states interplay via the dark field exchange, this process is analogous to four-wave mixing in quantum optics, where the frequency sum and difference among the incident three waves generate the fourth wave with a new frequency via the nonlinear property of crystals. The interaction rate of the four-wave mixing process has the cubic dependence on the intensity of each wave. Therefore, if high-intensity laser fields are given, the sensitivity to the weakly coupling of dark fields to photons rapidly increases over the wide mass range below sub-eV. Based on the experimentally measurable photon energies and the linear polarization states, we formulate the relation between the accessible mass-coupling domains and the high-intensity laser parameters, where the effects of the finite spectrum width of pulse lasers are taken into account. The expected sensitivity suggests that we have a potential to explore interactions at the Super-Planckian coupling strength in the sub-eV mass range, if the cutting-edge laser technologies are properly combined.

Kensuke Homma

2012-11-09T23:59:59.000Z

22

Compton harmonic resonances, stochastic instabilities, quasilinear diffusion, and collisionless damping with ultra-high intensity laser waves  

SciTech Connect

The dynamics of electrons in two-dimensional, linearly or circularly polarized, ultra-high intensity (above 10{sup 18}W/cm{sup 2}) laser waves, is investigated. The Compton harmonic resonances are identified as the source of various stochastic instabilities. Both Arnold diffusion and resonance overlap are considered. The quasilinear kinetic equation, describing the evolution of the electron distribution function, is derived, and the associated collisionless damping coefficient is calculated. The implications of these new processes are considered and discussed.

Rax, J.M.

1992-04-01T23:59:59.000Z

23

Laser sustained discharge nozzle apparatus for the production of an intense beam of high kinetic energy atomic species  

DOE Patents (OSTI)

Laser sustained discharge apparatus for the production of intense beams of high kinetic energy atomic species. A portion of the plasma resulting from a laser sustained continuous optical discharge which generates energetic atomic species from a gaseous source thereof is expanded through a nozzle into a region of low pressure. The expanded plasma contains a significant concentration of the high kinetic energy atomic species which may be used to investigate the interaction of surfaces therewith. In particular, O-atoms having velocities in excess of 3.5 km/s can be generated for the purpose of studying their interaction with materials in order to develop protective materials for spacecraft which are exposed to such energetic O-atoms during operation in low earth orbit.

Cross, Jon B. (Santa Fe, NM); Cremers, David A. (Los Alamos, NM)

1988-01-01T23:59:59.000Z

24

Laser sustained discharge nozzle apparatus for the production of an intense beam of high kinetic energy atomic species  

DOE Patents (OSTI)

Laser sustained discharge apparatus for the production of intense beams of high kinetic energy atomic species is described. A portion of the plasma resulting from a laser sustained continuous optical discharge which generates energetic atomic species from a gaseous source thereof is expanded through a nozzle into a region of low pressure. The expanded plasma contains a significant concentration of the high kinetic energy atomic species which may be used to investigate the interaction of surfaces therewith. In particular, O-atoms having velocities in excess of 3.5 km/s can be generated for the purpose of studying their interaction with materials in order to develop protective materials for spacecraft which are exposed to such energetic O-atoms during operation in low earth orbit.

Cross, J.B.; Cremers, D.A.

1986-01-10T23:59:59.000Z

25

Production of high-density high-temperature plasma by collapsing small solid-density plasma shell with two ultra-intense laser pulses  

Science Conference Proceedings (OSTI)

Three-dimensional particle-in-cell simulations show that the anisotropic collapse of a plasma microshell by impact of two oppositely directed intense laser pulses can create at the center of the shell cavity a submicron-sized plasma of high density and temperature suitable for generating fusion neutrons.

Xu, H. [National Laboratory for Parallel and Distributed Processing, School of Computer Science, National University of Defense Technology, Changsha 410073 (China); Research Center of Laser Fusion, Chinese Academy of Engineering Physics, Mianyang 621900 (China); Yu Wei [Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Yu, M. Y. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Institute for Theoretical Physics I, Ruhr University, Bochum D-44780 (Germany); Wong, A. Y. [Department of Physics, University of California, Los Angeles, California 90095 (United States); Sheng, Z. M.; Zhang, J. [Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Murakami, M. [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan)

2012-04-02T23:59:59.000Z

26

Polarisation response of a gas medium in the field of a high-intensity ultrashort laser pulse: high order Kerr nonlinearities or plasma electron component?  

SciTech Connect

The polarisation response of quantum systems modelling silver and xenon atoms in the field of a high-intensity femtosecond Ti : sapphire laser (photon energy h{omega} Almost-Equal-To 1.5 eV), has been investigated by direct numerical integration of the Schroedinger equation. The applicability ranges of the perturbation theory and polarisation expansion in powers of field are determined. The contributions of excited atoms and electrons in the continuous-spectrum states to the polarisation response at the fundamental frequency, which arise as a result of excitation and photoionisation, are analysed. It is shown that specifically ionisation changes the sign of dielectric susceptibility with an increase in radiation intensity for the systems under consideration. (interaction of laser radiation with matter. laser plasmas)

Volkova, E A; Popov, Alexander M; Tikhonova, O V [D.V. Skobel'tsyn Institute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow (Russian Federation)

2012-08-31T23:59:59.000Z

27

Using high-intensity laser-generated energetic protons to radiograph directly driven implosions  

Science Conference Proceedings (OSTI)

The recent development of petawatt-class lasers with kilojoule-picosecond pulses, such as OMEGA EP [L. Waxer et al., Opt. Photonics News 16, 30 (2005)], provides a new diagnostic capability to study inertial-confinement-fusion (ICF) and high-energy-density (HED) plasmas. Specifically, petawatt OMEGA EP pulses have been used to backlight OMEGA implosions with energetic proton beams generated through the target normal sheath acceleration (TNSA) mechanism. This allows time-resolved studies of the mass distribution and electromagnetic field structures in ICF and HED plasmas. This principle has been previously demonstrated using Vulcan to backlight six-beam implosions [A. J. Mackinnon et al., Phys. Rev. Lett. 97, 045001 (2006)]. The TNSA proton backlighter offers better spatial and temporal resolution but poorer spatial uniformity and energy resolution than previous D{sup 3}He fusion-based techniques [C. Li et al., Rev. Sci. Instrum. 77, 10E725 (2006)]. A target and the experimental design technique to mitigate potential problems in using TNSA backlighting to study full-energy implosions is discussed. The first proton radiographs of 60-beam spherical OMEGA implosions using the techniques discussed in this paper are presented. Sample radiographs and suggestions for troubleshooting failed radiography shots using TNSA backlighting are given, and future applications of this technique at OMEGA and the NIF are discussed.

Zylstra, A. B.; Li, C. K.; Rinderknecht, H. G.; Seguin, F. H.; Petrasso, R. D. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Stoeckl, C.; Meyerhofer, D. D.; Nilson, P.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Le Pape, S.; Mackinnon, A.; Patel, P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2012-01-15T23:59:59.000Z

28

Laser guiding at relativistic intensities and wakefield particle accleration in plasma channels  

E-Print Network (OSTI)

Laser Guiding at Relativistic Intensities and Wakefieldfirst time in a high gradient laser wakefield accelerator byguiding the drive laser pulse. Channels formed by

2004-01-01T23:59:59.000Z

29

Intense laser field ionization of atom and molecular ion.  

E-Print Network (OSTI)

??In order to understand how does the intense laser interact with matter we first of all study the ionization process. In this highly nonlinear region… (more)

Long, Zi Jian

2008-01-01T23:59:59.000Z

30

Harmonic generation at high intensities  

Science Conference Proceedings (OSTI)

Atomic electrons subject to intense laser fields can absorb many photons, leading either to multiphoton ionization or the emission of a single, energetic photon which can be a high multiple of the laser frequency. The latter process, high-order harmonic generation, has been observed experimentally using a range of laser wavelengths and intensities over the past several years. Harmonic generation spectra have a generic form: a steep decline for the low order harmonics, followed by a plateau extending to high harmonic order, and finally an abrupt cutoff beyond which no harmonics are discernible. During the plateau the harmonic production is a very weak function of the process order. Harmonic generation is a promising source of coherent, tunable radiation in the XUV to soft X-ray range which could have a variety of scientific and possibly technological applications. Its conversion from an interesting multiphoton phenomenon to a useful laboratory radiation source requires a complete understanding of both its microscopic and macroscopic aspects. We present some recent results on the response of single atoms at intensities relevant to the short pulse experiments. The calculations employ time-dependent methods, which we briefly review in the next section. Following that we discuss the behavior of the harmonics as a function of laser intensity. Two features are notable: the slow scaling of the harmonic intensities with laser intensity, and the rapid variation in the phase of the individual harmonics with respect to harmonic order. We then give a simple empirical formula that predicts the extent of the plateau for a given ionization potential, wavelength and intensity.

Schafer, K.J.; Krause, J.L.; Kulander, K.C.

1993-06-01T23:59:59.000Z

31

Relativistic effects in the interaction of high intensity ultra-short laser pulse with collisional underdense plasma  

SciTech Connect

In this paper, the effect of weakly relativistic ponderomotive force in the interaction of intense laser pulse with nonisothermal, underdense, collisional plasma is studied. Ponderomotive force modifies the electron density and temperature distribution. By considering the weakly relativistic effect and ohmic heating of plasma electrons, the nonlinear dielectric permittivity of plasma medium is obtained and the equation of electromagnetic wave propagation in plasma is solved. It is shown that with considering the ohmic heating of electrons and collisions, the effect of ponderomotive force in weakly relativistic regime leads to steepening the electron density profile and increases the temperature of plasma electrons noticeably. Bunches of electrons in plasma become narrower. By increasing the laser pulse strength, the wavelength of density oscillations decreases. In this regime of laser-plasma interaction, electron temperature increases sharply by increasing the intensity of laser pulse. The amplitude of electric and magnetic fields increases by increasing the laser pulse energy while their wavelength decreases and they lost their sinusoidal form.

Abedi, Samira [Physics Department, North Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Dorranian, Davoud [Laser Lab., Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Abari, Mehdi Etehadi [Physics Department, Science Faculty, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Shokri, Babak [Physics Department, Science Faculty, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Laser-Plasma Research Institute, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of)

2011-09-15T23:59:59.000Z

32

HILL: The High-Intensity Laser Laboratory Core Team's Reply to Questions from the NNSA Experimental Facilities Panel  

SciTech Connect

Question 1 - The type of physics regimes that HILL can access for weapons studies is quite interesting. The question that arises for the proposal team is what priority does this type of experimental data have versus data that can be obtained with NIF, and Z. How does HILL rank in priority compared to MARIE 1.0 in terms of the experimental data it will provide? We reiterate that isochoric heating experiments to be conducted with HILL are complementary to the high energy density physics experiments at NIF and Z and uniquely access states of matter that neither other facility can access. It is our belief that HILL will enable several important questions, e.g., as related to mix morphology, radiation transfer from corrugated surfaces, and equations of state, to be run to ground through carefully diagnosed, 'unit-physics' experiments. Such experiments will substantially improve confidence in our computer models and provide a rigorous science basis for certification. Question 2 - A secondary question relates to the interests of LLNL and SNL in the physics that HILL can address. This should be spelled out clearly. I would like to see the other labs be part of the discussion regarding how important this capability would be if built. Both sister Labs have a keen interest in the physics enabled by high-intensity, high-energy lasers, as evinced by the Z Petawatt and NIF ARC upgrades to their signature facilities. LANL scientists have teamed with scientists from both Laboratories in high-intensity laser 'first experiments' envisioned for HILL and we fully intend to continue these profitable discussions going forward. In the preparation of the HILL proposal, feedback was solicited from the broader HEDP and weapons science communities. The consensus view was that HILL filled a critical gap and that there was a need for a facility like HILL to address outstanding questions in weapons science. It was recognized that co-location of HILL with a facility such as MaRIE 1.0, Z, NIF, or Omega may offer additional advantages and we would expect these to be explored and evaluated during the CD process. Question 3 - A laser/optics experts group should review this proposal to ensure the level of R&D is reasonable to provide a sufficient chance of success (>50%). In the preparation of the HILL proposal, we sent our proposal and cost estimates to laser designers/scientists across the complex. Though risks were identified with our design, the prevailing view of those we engaged was that the risks were appropriately represented by the TRL levels assigned and that the enabling R&D planned in our proposal was adequate for risk mitigation. Question 4 - More data and peer review is needed from its sister facilities around the world. It is our specific intent to conduct both scientific and technical workshops with the user community if the High Intensity Science field is further encouraged as part of the NNSA Roadmap. Question 5 - Does HILL have to be co-located with MARIE 1.0? Is that feasible from the point of view of TA-53 real estate? Multiple siting options were considered for HILL, including co-location with MaRIE 1.0 (the most cost-effective and flexible option), as well as in a separate, stand-alone building and in a retro-fitted existing building. The cost estimate included these contingencies and candidate locations for HILL in TA-53 were identified. There is actually significant space at TA-53 on the hill in the northeast end of the mesa. Question 6 - What would be the impact on the weapons program if this facility were NOT built? An inability to elucidate aspects of weapons science in the dense plasma regime and validate computer models for same. This will lead to reduced confidence in the computer tools used for certification. Question 7 - Will HILL allow some of the x-ray vulnerability studies proposed by SPARC? If so what does Sandia's vulnerability group think of this method versus SPARC. It is possible that some of the scope envisioned for SPARC could be achieved on HILL, although likely that the energy produced at HILL not bei

Albright, B J [Los Alamos National Laboratory

2012-08-02T23:59:59.000Z

33

Formation of silver nanoparticles inside a soda-lime glass matrix in the presence of a high intensity Ar{sup +} laser beam  

SciTech Connect

Formation and motion of the silver nanoparticles inside an ion-exchanged soda-lime glass in the presence of a focused high intensity continuous wave Ar{sup +} laser beam (intensity: 9.2 x 10{sup 4} W/cm{sup 2}) have been studied in here. One-dimensional diffusion equation has been used to model the diffusion of the silver ions into the glass matrix, and a two-dimensional reverse diffusion model has been introduced to explain the motion of the silver clusters and their migration toward the glass surface in the presence of the laser beam. The results of the mentioned models were in agreement with our measurements on thickness of the ion-exchange layer by means of optical microscopy and recorded morphology of the glass surface around the laser beam axis by using a Mirau interferometer. SEM micrographs were used to extract the size distribution of the migrated silver particles over the glass surface.

Niry, M. D.; Khalesifard, H. R. [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Optics Research Center, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Mostafavi-Amjad, J.; Ahangary, A. [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Azizian-Kalandaragh, Y. [Department of Physics, Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan 45137-66731 (Iran, Islamic Republic of); Department of Physics, University of Mohaghegh Ardabili (UMA), P.O. Box 179, Ardabil (Iran, Islamic Republic of)

2012-02-01T23:59:59.000Z

34

High intensity hadron accelerators  

SciTech Connect

This rapporteur report consists mainly of two parts. Part I is an abridged review of the status of all High Intensity Hadron Accelerator projects in the world in semi-tabulated form for quick reference and comparison. Part II is a brief discussion of the salient features of the different technologies involved. The discussion is based mainly on my personal experiences and opinions, tempered, I hope, by the discussions I participated in in the various parallel sessions of the workshop. In addition, appended at the end is my evaluation and expression of the merits of high intensity hadron accelerators as research facilities for nuclear and particle physics.

Teng, L.C.

1989-05-01T23:59:59.000Z

35

Spectral broadening and compression of high-intensity laser pulses in quasi-periodic systems with Kerr nonlinearity  

SciTech Connect

We report the results of theoretical studies and numerical simulations of optical high-power pulse compression systems based on the spectral broadening in a Kerr nonlinear medium with subsequent pulse compression in a dispersive delay line. It is shown that the effective spectral broadening requires suppressing a smallscale instability arising due to self-focusing, which is possible in quasi-periodic systems consisting of a nonlinear medium and optical relay telescopes transmitting images of the laser beam through the system. The numerical calculations have shown the possibility of broadening the spectrum, followed by 15-fold pulse compression until the instability is excited. (control of laser radiation parameters)

Vlasov, Sergei N; Koposova, E V; Yashin, V E

2012-11-30T23:59:59.000Z

36

X-ray polarization spectroscopy to study anisotropic velocity distribution of hot electrons produced by an ultra-high-intensity laser  

SciTech Connect

The anisotropy of the hot-electron velocity distribution in ultra-high-intensity laser produced plasma was studied with x-ray polarization spectroscopy using multilayer planar targets including x-ray emission tracer in the middle layer. This measurement serves as a diagnostic for hot-electron transport from the laser-plasma interaction region to the overdense region where drastic changes in the isotropy of the electron velocity distribution are observed. These polarization degrees are consistent with analysis of a three-dimensional polarization spectroscopy model coupled with particle-in-cell simulations. Electron velocity distribution in the underdense region is affected by the electric field of the laser and that in the overdense region becomes wider with increase in the tracer depth. A full-angular spread in the overdense region of 22.4 deg.{sub -2.4}{sup +5.4} was obtained from the measured polarization degree.

Inubushi, Y. [Institute of Laser Engineering, Osaka University, Suita, Osaka (Japan); Graduate School of Engineering, Osaka University, Suita, Osaka (Japan); Okano, Y.; Nishimura, H.; Cai, H.; Nagatomo, H.; Kai, T.; Fujioka, S.; Nakamura, T.; Johzaki, T.; Mima, K. [Institute of Laser Engineering, Osaka University, Suita, Osaka (Japan); Kawamura, T. [Tokyo Institute of Technology, Yokohama, Kanagawa (Japan); Batani, D.; Morace, A.; Redaelli, R. [Dipartmento di Fisica 'G. Occhialini', University of Milano-Bicocca, Milan (Italy); Fourment, C.; Santos, J. J.; Malka, G. [CELIA, Universite de Bordeaux/CNRS/CEA, Talence (France); Boscheron, A.; Bonville, O.; Grenier, J. [CEA/CESTA, Le Barp (France)

2010-03-15T23:59:59.000Z

37

High-Intensity Laser Interactions with Mass-Limited Solid Targets and Implications for Fast-Ignition Experiments on OMEGA EP  

Science Conference Proceedings (OSTI)

The modeling of petawatt laser-generated hot electrons in mass-limited solid-foil-target interactions at "relativistic" laser intensities is presented using copper targets and parameters motivated by recent experiments at the Rutherford Appleton Laboratory Petawatt and 100-TW facilities. Electron refluxing allows a unique determination of the laser-electron conversion efficiency and a test with simulations.

Myatt, J.; Theobald, W.; Delettrez, J.A.; Stoeckl, C.; Storm, M.; Sangster, T.C.; Maximov, A.V.; Short, R.W.

2007-03-23T23:59:59.000Z

38

Dependence of terahertz power from laser-produced plasma on laser intensity  

SciTech Connect

Power of terahertz radiation from plasma which is generated from air irradiated by coupled ({omega}, 2{omega}) femtosecond laser pulses is analyzed for high laser intensities, for which non-linear plasma effects on the pulse propagation become essential, with multidimensional particle-in-cell simulations including the self-consistent plasma kinetics. The growth rate of THz power becomes slower as the laser intensity increases. A reason of such a lowering of efficiency in THz emission is found to be ionization of air by the laser pulse, which results in poor focusing of laser pulses.

Shin, J.-H.; Zhidkov, A.; Jin, Z.; Hosokai, T.; Kodama, R. [Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita, Osaka 565-0871 (Japan); Photon Pioneers Center, Osaka University, 2-1, Yamadaoka, Suita, Osaka 565-0871 (Japan); Japan Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka (Japan)

2012-07-11T23:59:59.000Z

39

Optimizing electron-positron pair production on kilojoule-class high-intensity lasers for the purpose of pair-plasma creation  

Science Conference Proceedings (OSTI)

Expressions for the yield of electron-positron pairs, their energy spectra, and production rates have been obtained in the interaction of multi-kJ pulses of high-intensity laser light interacting with solid targets. The Bethe-Heitler conversion of hard x-ray bremsstrahlung [D. A. Gryaznykh, Y. Z. Kandiev, and V. A. Lykov, JETP Lett. 67, 257 (1998); K. Nakashima and H. Takabe, Phys. Plasmas 9, 1505 (2002)] is shown to dominate over direct production (trident process) [E. P. Liang, S. C. Wilks, and M. Tabak, Phys. Rev. Lett. 81, 4887 (1998)]. The yields and production rates have been optimized as a function of incident laser intensity by the choice of target material and dimensions, indicating that up to 5x10{sup 11} pairs can be produced on the OMEGA EP laser system [L. J. Waxer et al., Opt. Photonics News 16, 30 (2005)]. The corresponding production rates are high enough to make possible the creation of a pair plasma.

Myatt, J.; Delettrez, J. A.; Maximov, A. V.; Meyerhofer, D. D.; Short, R. W.; Stoeckl, C.; Storm, M. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States)

2009-06-15T23:59:59.000Z

40

Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions  

SciTech Connect

We present results from the grant entitled, ���¢��������Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions.���¢������� The research significantly advanced the understanding of basic high-energy density science (HEDS) on ultra intense laser and particle beam plasma interactions. This advancement in understanding was then used to to aid in the quest to make 1 GeV to 500 GeV plasma based accelerator stages. The work blended basic research with three-dimensions fully nonlinear and fully kinetic simulations including full-scale modeling of ongoing or planned experiments. The primary tool was three-dimensional particle-in-cell simulations. The simulations provided a test bed for theoretical ideas and models as well as a method to guide experiments. The research also included careful benchmarking of codes against experiment. High-fidelity full-scale modeling provided a means to extrapolate parameters into regimes that were not accessible to current or near term experiments, thereby allowing concepts to be tested with confidence before tens to hundreds of millions of dollars were spent building facilities. The research allowed the development of a hierarchy of PIC codes and diagnostics that is one of the most advanced in the world.

Mori, Warren, B.

2012-12-01T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" 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.


41

Quantitative Interpretation of Laser Ceilometer Intensity Profiles  

Science Conference Proceedings (OSTI)

The authors have used a commercially available laser ceilometer to measure vertical profiles of the optical extinction in rain. This application requires special signal processing to correct the raw data for the effects of receiver noise, high-...

R. R. Rogers; M-F. Lamoureux; L. R. Bissonnette; R. M. Peters

1997-06-01T23:59:59.000Z

42

High-Intensity Discharge Lighting  

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

High-intensity discharge (HID) lighting provides the highest efficacy and longest service life of any lighting type. It can save 75%-90% of lighting energy when it replaces incandescent lighting.

43

Atomic processes in plasmas under ultra-intense laser irradiation  

Science Conference Proceedings (OSTI)

Lasers delivering subpicosecond pulses with energies of a fraction of a Joule have made it possible to generate irradiance levels approaching 10{sup 20} W/cm{sup 2}. We presently operate two such systems, a KrF based excimer laser capable of producing a few 10{sup 17} W/cm{sup 2} at 248 nm with a repetition rate of 3--5 Hz and a XeCl based excimer laser capable of producing mid 10{sup 19} W/cm{sup 2} at 308 nm and 1 Hz. We will discuss some experimental results and the theory and modeling of the interaction of such intense laser pulses with aluminum. Because of a small ASE prepulse the high intensity interaction is not at the solid surface but rather at the n{sub e} = 2 {times} 10{sup 22} cm{sup {minus}3} critical density of the blowoff plasma generated by the ASE. The transient behavior of the plasma following the energy deposition by the intense subpicosecond pulse can be viewed as the energy-impulse response of the plasma. Experimental results and modeling of the x-ray emission from this plasma will be presented. 15 refs., 8 figs.

Schappert, G.T.; Casperson, D.E.; Cobble, J.A.; Comly, J.C.; Jones, L.A.; Kyrala, G.A.; LaGattuta, K.J.; Lee, P.H.Y.; Olson, G.L.; Taylor, A.J.

1989-11-01T23:59:59.000Z

44

Photoionization of hydrogen atom by coherent intense high-frequency short laser pulses: Direct propagation of electron wave packets on enormous spatial grids  

E-Print Network (OSTI)

The time-dependent Schr\\"{o}dinger equation for the hydrogen atom and its interaction with coherent intense high-frequency short laser pulses is solved numerically exactly by employing the code implemented for the multi-configurational time-dependent Hartree-Fock (MCTDHF) method. Thereby, the wavefunction is followed in space and time for times longer than the pulse duration. Results are explicitly shown for 3 and 10 fs pulses. Particular attention is paid to identifying the effect of dynamic interference of photoelectrons emitted with the same kinetic energy at different times during the rising and falling sides of the pulse predicted in [\\emph{Ph.V. Demekhin and L.S. Cederbaum}, Phys. Rev. Lett. \\textbf{108}, 253001 (2012)]. In order to be able to see the dynamic interference pattern in the computed electron spectra, the photoelectron wave packet has to be propagated over long distances. Clearly, complex absorption potentials often employed to compute spectra of emitted particles cannot be used to detect dy...

Demekhin, Philipp V; Cederbaum, Lorenz S

2013-01-01T23:59:59.000Z

45

Very high intensity reaction chamber design  

SciTech Connect

The problem of achieving very high intensity irradiation by light in minimal regions was studied. Three types of irradiation chamber are suggested: the common laser-reaction chamber, the folded concentric or near-concentric resonator, and the asymmetric confocal resonator. In all designs the ratio of high-intensity illuminated volume to other volume is highly dependent (to the $sup 3$/$sub 2$ power) on the power and fluence tolerances of optical elements, primarily mirrors. Optimization of energy coupling is discussed for the common cavity. For the concentric cavities, optimization for both coherent and incoherent beams is treated. Formulae and numerical examples give the size of chambers, aspect ratios, maximum pass number, image sizes, fluences, and the like. Similarly for the asymmetric confocal chamber, formulae and numerical examples for fluences, dimensions, losses, and totally contained pass numbers are given. (auth)

Devaney, J.J.

1975-09-01T23:59:59.000Z

46

Intensity clamping in the filament of femtosecond laser radiation  

SciTech Connect

We have studied numerically the evolution of the light field intensity and induced refractive index of a medium upon filamentation of femtosecond laser radiation in air. It is shown that the intensity clamping results from the dynamic balance of optical powers of nonlinear lenses, induced by radiation due to the Kerr nonlinearity of air, and laser plasma produced during photoionisation. We have found the relation between the peak values of the light field intensity and the electron density in laser-produced plasma, as well as the transverse sizes of the filament and the plasma channel. (effects of laser radiation on matter)

Kandidov, V P; Fedorov, V Yu; Tverskoi, O V; Kosareva, O G; Chin, S L

2011-04-30T23:59:59.000Z

47

System for obtaining smooth laser beams where intensity variations are reduced by spectral dispersion of the laser light (SSD)  

DOE Patents (OSTI)

In an SSD (smoothing by spectral dispersion) system which reduces the time-averaged spatial variations in intensity of the laser light to provide uniform illumination of a laser fusion target, an electro-optic phase modulator through which a laser beam passes produces a broadband output beam by imposing a frequency modulated bandwidth on the laser beam. A grating provides spatial and angular spectral dispersion of the beam. Due to the phase modulation, the frequencies ("colors") cycle across the beam. The dispersed beam may be amplified and frequency converted (e.g., tripled) in a plurality of beam lines. A distributed phase plate (DPP) in each line is irradiated by the spectrally dispersed beam and the beam is focused on the target where a smooth (uniform intensity) pattern is produced. The color cycling enhances smoothing and the use of a frequency modulated laser pulse prevents the formation of high intensity spikes which could damage the laser medium in the power amplifiers.

Skupsky, Stanley (Rochester, NY); Kessler, Terrance J. (Rochester, NY); Short, Robert W. (Rochester, NY); Craxton, Stephen (Rochester, NY); Letzring, Samuel A. (Honeoye Falls, NY); Soures, John (Pittsford, NY)

1991-01-01T23:59:59.000Z

48

Intense transient magnetic-field generation by laser plasma  

DOE Patents (OSTI)

In a laser system, the return current of a laser generated plasma is conducted near a target to subject that target to the magnetic field thereof. In alternate embodiments the target may be either a small non-fusion object for testing under the magnetic field or a laser-fusion pellet. In the laser-fusion embodiment, the laser-fusion pellet is irradiated during the return current flow and the intense transient magnetic field is used to control the hot electrons thereof to hinder them from striking and heating the core of the irradiated laser-fusion pellet.

Benjamin, R.F.

1981-08-18T23:59:59.000Z

49

Imaging the geometrical structure of the H{sub 2}{sup +} molecular ion by high-order above-threshold ionization in an intense laser field  

Science Conference Proceedings (OSTI)

Using a frequency-domain theory, we demonstrate that an angle-resolved high-order above-threshold ionization (HATI) spectrum carries three pieces of important information: the fingerprint of the molecular wave function in the direct above-threshold-ionization amplitude, the geometrical structure of the molecule in the potential scattering between two plane waves, and the interaction between the ionized electron and the laser field, manifested in a phase factor associated with laser-assisted collisions. As a result all main interference features in the HATI spectrum can be physically explained. As an application it is pointed out that the skeleton structure of a molecule can be better imaged using lasers of higher frequencies.

Guo Yingchun [Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062 (China); Fu Panming; Wang Bingbing [Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Yan Zongchao [Department of Physics, University of New Brunswick, P.O. Box 4400, Fredericton, New Brunswick, Canada E3B 5A3 (Canada); Center for Theoretical Atomic and Molecular Physics, Academy of Fundamental and Interdisciplinary Sciences, Harbin Institute of Technology, Harbin 150080 (China); Gong Jiangbin [Department of Physics and Center of Computational Science and Engineering, National University of Singapore, Singapore 117542 (Singapore)

2009-12-15T23:59:59.000Z

50

Gratings for High-Energy Petawatt Lasers  

Science Conference Proceedings (OSTI)

To enable high-energy petawatt laser operation we have developed the processing methods and tooling that produced both the world's largest multilayer dielectric reflection grating and the world's highest laser damage resistant gratings. We have successfully delivered the first ever 80 cm aperture multilayer dielectric grating to LLNL's Titan Intense Short Pulse Laser Facility. We report on the design, fabrication and characterization of multilayer dielectric diffraction gratings.

Nguyen, H T; Britten, J A; Carlson, T C; Nissen, J D; Summers, L J; Hoaglan, C R; Aasen, M D; Peterson, J E; Jovanovic, I

2005-11-08T23:59:59.000Z

51

Request for Support for the Conference on Super Intense Laser Atom Physics  

Science Conference Proceedings (OSTI)

The Conference on Super Intense Laser Atom Physics (SILAP) was held in November 2003 in Dallas, Texas. The venue for the meeting was South Fork Ranch in the outskirts of Dallas. The topics of the meeting included high harmonic generation and attosecond pulse generation, strong field interactions with molecules and clusters, particle acceleration, and relativistic laser atom interactions.

Todd Ditmire

2004-10-21T23:59:59.000Z

52

High intensity protons in RHIC  

SciTech Connect

During the 2012 summer shutdown a pair of electron lenses will be installed in RHIC, allowing the beam-beam parameter to be increased by roughly 50 percent. To realize the corresponding luminosity increase bunch intensities have to be increased by 50 percent, to 2.5 {center_dot} 10{sup 11} protons per bunch. We list the various RHIC subsystems that are most affected by this increase, and propose beam studies to ensure their readiness. The proton luminosity in RHIC is presently limited by the beam-beam effect. To overcome this limitation, electron lenses will be installed in IR10. With the help of these devices, the headon beam-beam kick experienced during proton-proton collisions will be partially compensated, allowing for a larger beam-beam tuneshift at these collision points, and therefore increasing the luminosity. This will be accomplished by increasing the proton bunch intensity from the presently achieved 1.65 {center_dot} 10{sup 11} protons per bunch in 109 bunches per beam to 2.5 {center_dot} 10{sup 11}, thus roughly doubling the luminosity. In a further upgrade we aim for bunch intensities up to 3 {center_dot} 10{sup 11} protons per bunch. With RHIC originally being designed for a bunch intensity of 1 {center_dot} 10{sup 11} protons per bunch in 56 bunches, this six-fold increase in the total beam intensity by far exceeds the design parameters of the machine, and therefore potentially of its subsystems. In this note, we present a list of major subsystems that are of potential concern regarding this intensity upgrade, show their demonstrated performance at present intensities, and propose measures and beam experiments to study their readiness for the projected future intensities.

Montag, C.; Ahrens& #44; L.; Blaskiewicz& #44; M.; Brennan& #44; J.M.; Drees& #44; K.A.; Fischer& #44; W.; Huang& #44; H.; Minty& #44; M.; Robert-Demolaize& #44; G.; Thieberger& #44; P.; Yip& #44; K.

2012-01-05T23:59:59.000Z

53

STABILIZED HIGH INTENSITY SOURCE OF 80 kv  

SciTech Connect

With the change of the current load from 0 to 2.5 mamp and simultaneous change of incoming intensity from 270 to 190 v, the stabilized high-intensity source changes less than l%.. The stabilized intensity can be arranged in steps of 5 kv from 60 to 80 kv. The high-intensity stabilizer automatically switches on upon reaching 60 kv. (tr-auth)

Polivanov, V.V.; Izyurov, A.V.; Pyatakov, N.I.

1959-09-01T23:59:59.000Z

54

High-performance laser processing using manipulated ultrafast laser pulses  

Science Conference Proceedings (OSTI)

We employ manipulated ultrafast laser pulses to realize microprocessing with high-performance. Efficient microwelding of glass substrates by irradiation by a double-pulse train of ultrafast laser pulses is demonstrated. The bonding strength of two photostructurable glass substrates welded by double-pulse irradiation was evaluated to be 22.9 MPa, which is approximately 22% greater than that of a sample prepared by conventional irradiation by a single pulse train. Additionally, the fabrication of hollow microfluidic channels with a circular cross-sectional shape embedded in fused silica is realized by spatiotemporally focusing the ultrafast laser beam. We show both theoretically and experimentally that the spatiotemporal focusing of ultrafast laser beam allows for the creation of a three-dimensionally symmetric spherical peak intensity distribution at the focal spot.

Sugioka, Koji; Cheng Ya; Xu Zhizhan; Hanada, Yasutaka; Midorikawa, Katsumi [RIKEN - Advanced Science Institute, Wako, Saitama 351-0198 (Japan); State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences (China); RIKEN - Advanced Science Institute, Wako, Saitama 351-0198 (Japan)

2012-07-30T23:59:59.000Z

55

Transverse instability in high intensity proton rings  

SciTech Connect

In recent years, many applications are being considered for low energy high intensity proton synchrotrons. Most high intensity proton rings are at low energy below transition. Several aspects of the beam dynamics of this kind of rings are different from the electron or high energy rings. The transverse microwave instabilities will be discussed in this article.

Zhang, S.Y.; Weng, W.T.

1997-07-01T23:59:59.000Z

56

Explosive photodissociation of methane induced by ultrafast intense laser  

SciTech Connect

A new type of molecular fragmentation induced by femtosecond intense laser at the intensity of 2x10{sup 14} W/cm{sup 2} is reported. For the parent molecule of methane, ethylene, n-butane, and 1-butene, fluorescence from H (n=3{yields}2), CH (A {sup 2}{delta}, B {sup 2}{sigma}{sup -}, and C {sup 2}{sigma}{sup +}{yields}X {sup 2}{pi}), or C{sub 2} (d {sup 3}{pi}{sub g}{yields}a {sup 3}{pi}{sub u}) is observed in the spectrum. It shows that the fragmentation is a universal property of neutral molecule in the intense laser field. Unlike breaking only one or two chemical bonds in conventional UV photodissociation, the fragmentation caused by the intense laser undergoes vigorous changes, breaking most of the bonds in the molecule, like an explosion. The fragments are neutral species and cannot be produced through Coulomb explosion of multiply charged ion. The laser power dependence of CH (A{yields}X) emission of methane on a log-log scale has a slope of 10{+-}1. The fragmentation is thus explained as multiple channel dissociation of the superexcited state of parent molecule, which is created by multiphoton excitation.

Kong Fanao; Luo Qi; Xu Huailiang; Sharifi, Mehdi; Song Di; Chin, See Leang [Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China); Department of Physics, Engineering Physics and Optics, Laval University, Quebec G1K 7P4, Canada and Center for Optics, Photonics, and Laser, Laval University, Quebec G1K 7P4 (Canada); Institute of Chemistry, Chinese Academy of Sciences, Beijing 100080 (China); Department of Physics, Engineering Physics and Optics, Laval University, Quebec G1K 7P4 (Canada) and Center for Optics, Photonics, and Laser, Laval University, Quebec G1K 7P4 (Canada)

2006-10-07T23:59:59.000Z

57

Making Relativistic Positrons Using Ultra-Intense Short Pulse Lasers  

Science Conference Proceedings (OSTI)

This paper describes a new positron source produced using ultra-intense short pulse lasers. Although it has been studied in theory since as early as the 1970s, the use of lasers as a valuable new positron source was not demonstrated experimentally until recent years, when the petawatt-class short pulse lasers were developed. In 2008 and 2009, in a series of experiments performed at Lawrence Livermore National Laboratory, a large number of positrons were observed after shooting a millimeter thick solid gold target. Up to 2 x 10{sup 10} positrons per steradian ejected out the back of {approx}mm thick gold targets were detected. The targets were illuminated with short ({approx}1 ps) ultra-intense ({approx}1 x 10{sup 20} W/cm{sup 2}) laser pulses. These positrons are produced predominantly by the Bethe-Heitler process, and have an effective temperature of 2-4 MeV, with the distribution peaking at 4-7 MeV. The angular distribution of the positrons is anisotropic. For a wide range of applications, this new laser based positron source with its unique characteristics may complements the existing sources using radioactive isotopes and accelerators.

Chen, H; Wilks, S; Bonlie, J; Chen, C; Chen, S; Cone, K; Elberson, L; Gregori, G; Liang, E; Price, D; Van Maren, R; Meyerhofer, D D; Mithen, J; Murphy, C V; Myatt, J; Schneider, M; Shepherd, R; Stafford, D; Tommasini, R; Beiersdorfer, P

2009-08-24T23:59:59.000Z

58

High intensity performance of the Brookhaven AGS  

SciTech Connect

Experience and results from recent high intensity proton running periods of the Brookhaven AGS, during which a record intensity for a proton synchrotron of 6.3 x 10{sup 13} protons/pulse was reached, is presented. This high beam intensity allowed for the simultaneous operation of three high precision rare kaon decay experiments. The record beam intensities were achieved after the 1.5 GeV Booster was commissioned and a transition jump system, a powerful transverse damper, and an rf upgrade in the AGS were completed. Recently even higher intensity proton synchrotrons are studied for neutron spallation sources or proton driver for a muon collider. Implications of the experiences from the AGS to these proposals and also possible future upgrades for the AGS are discussed.

Brennan, J.M.; Roser, T.

1996-07-01T23:59:59.000Z

59

Stationary self-focusing of intense laser beam in cold quantum plasma using ramp density profile  

SciTech Connect

By using a transient density profile, we have demonstrated stationary self-focusing of an electromagnetic Gaussian beam in cold quantum plasma. The paper is devoted to the prospects of using upward increasing ramp density profile of an inhomogeneous nonlinear medium with quantum effects in self-focusing mechanism of high intense laser beam. We have found that the upward ramp density profile in addition to quantum effects causes much higher oscillation and better focusing of laser beam in cold quantum plasma in comparison to that in the classical relativistic case. Our computational results reveal the importance and influence of formation of electron density profiles in enhancing laser self-focusing.

Habibi, M. [Department of Physics, Shirvan Branch, Islamic Azad University, Shirvan (Iran, Islamic Republic of); Ghamari, F. [Department of Physics, Khorramabad Branch, Islamic Azad University, Khorramabad (Iran, Islamic Republic of)

2012-10-15T23:59:59.000Z

60

Computational Simulations of High Intensity X-Ray Matter Interaction  

SciTech Connect

Free electron lasers have the promise of producing extremely high-intensity short pulses of coherent, monochromatic radiation in the 1-10 keV energy range. For example, the Linac Coherent Light Source at Stanford is being designed to produce an output intensity of 2 x 10{sup 14} W/cm{sup 2} in a 230 fs pulse. These sources will open the door to many novel research studies. However, the intense x-ray pulses may damage the optical components necessary for studying and controlling the output. At the full output intensity, the dose to optical components at normal incidence ranges from 1-10 eV/atom for low-Z materials (Z < 14) at photon energies of 1 keV. It is important to have an understanding of the effects of such high doses in order to specify the composition, placement, and orientation of optical components, such as mirrors and monochromators. Doses of 10 eV/atom are certainly unacceptable since they will lead to ablation of the surface of the optical components. However, it is not precisely known what the damage thresholds are for the materials being considered for optical components for x-ray free electron lasers. In this paper, we present analytic estimates and computational simulations of the effects of high-intensity x-ray pulses on materials. We outline guidelines for the maximum dose to various materials and discuss implications for the design of optical components.

London, R A; Rionta, R; Tatchyn, R; Roessler, S

2001-08-02T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" 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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61

High-Intensity Proton Accelerator  

SciTech Connect

Analysis is presented for an eight-cavity proton cyclotron accelerator that could have advantages as compared with other accelerators because of its potentially high acceleration gradient. The high gradient is possible since protons orbit in a sequence of TE111 rotating mode cavities of equally diminishing frequencies with path lengths during acceleration that greatly exceed the cavity lengths. As the cavities operate at sequential harmonics of a basic repetition frequency, phase synchronism can be maintained over a relatively wide injection phase window without undue beam emittance growth. It is shown that use of radial vanes can allow cavity designs with significantly smaller radii, as compared with simple cylindrical cavities. Preliminary beam transport studies show that acceptable extraction and focusing of a proton beam after cyclic motion in this accelerator should be possible. Progress is also reported on design and tests of a four-cavity electron counterpart accelerator for experiments to study effects on beam quality arising from variations injection phase window width. This device is powered by four 500-MW pulsed amplifiers at 1500, 1800, 2100, and 2400 MHz that provide phase synchronous outputs, since they are driven from a with harmonics derived from a phase-locked 300 MHz source.

Jay L. Hirshfield

2011-12-27T23:59:59.000Z

62

Isochoric heating of reduced mass targets by ultra-intense laser produced relativistic electrons  

Science Conference Proceedings (OSTI)

We present measurements of the chlorine K-alpha emission from reduced mass targets, irradiated with ultra-high intensity laser pulses. Chlorinated plastic targets with diameters down to 50 micrometers and mass of a few 10{sup -8} g were irradiated with up to 7 J of laser energy focused to intensities of several 10{sup 19} W/cm{sup 2}. The conversion of laser energy to K-alpha radiation is measured, as well as high resolution spectra that allow observation of line shifts, indicating isochoric heating of the target up to 18 eV. A zero-dimensional 2-temperature equilibration model, combined with electron impact K-shell ionization and post processed spectra from collisional radiative calculations reproduces the observed K-alpha yields and line shifts, and shows the importance of target expansion due to the hot electron pressure.

Neumayer, P; Lee, H J; Offerman, D; Shipton, E; Kemp, A; Kritcher, A L; Doppner, T; Back, C A; Glenzer, S H

2009-02-04T23:59:59.000Z

63

Mechanism and computational model for Lyman-{alpha}-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas  

SciTech Connect

We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-{alpha} (Ly-{alpha}) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-{alpha} generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-{alpha} radiation generation can achieve a value of {approx}5x10{sup -4} which is restricted by the total combined absorption of the fundamental and generated radiation.

Louchev, Oleg A.; Saito, Norihito; Wada, Satoshi [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Bakule, Pavel [STFC, ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX (United Kingdom); Yokoyama, Koji [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Ishida, Katsuhiko; Iwasaki, Masahiko [Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan)

2011-09-15T23:59:59.000Z

64

Energetic electron propagation in solid targets driven by the intense electric fields of femtosecond laser pulses  

Science Conference Proceedings (OSTI)

An analytical model is used to interpret experimental data on the propagation of energetic electrons perpendicular to and parallel to the propagation direction of intense femtosecond laser pulses that are incident on solid targets. The pulses with {approx_equal}10{sup 20} W/cm{sup 2} intensity are incident normal onto a gadolinium or tungsten wire embedded in an aluminum substrate, and MeV electrons generated in the focal spot propagate along the laser direction into the irradiated wire. Electrons also propagate laterally from the focal spot through the aluminum substrate and into a dysprosium or hafnium spectator wire at a distance up to 1 mm from the irradiated wire. The ratio of the K shell emission from the spectator and irradiated wires is a measure of the numbers and energies of the MeV electrons propagating parallel to and perpendicular to the intense oscillating electric field of the laser pulse. It is found that the angular distribution of electrons from the focal spot is highly non-isotropic, and approximately twice as many electrons are driven by the electric field toward the spectator wire as into the irradiated wire. This quantitative result is consistent with the qualitative experimental observation that the oscillating electric field of an intense femtosecond laser pulse, when interacting with a heavy metal target, preferentially drives energetic electrons in the electric field direction as compared to perpendicular to the field.

Seely, J. F. [Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375 (United States); Szabo, C. I. [Artep, Inc., 2922 Excelsior Spring Circle, Ellicott City, Maryland 21042 (United States); Audebert, P.; Brambrink, E. [Laboratoire pour L'Utilisation des Lasers Intenses (LULI), Ecole Polytechnique, 91128 Palaiseau Cedex (France)

2011-06-15T23:59:59.000Z

65

Generation of strongly coupled Xe cluster nanoplasmas by low intensive soft x-ray laser irradiation  

Science Conference Proceedings (OSTI)

A seeding gas jet including Xe clusters was irradiated with a laser-driven plasma soft x-ray laser pulse ({lambda}=13.9 nm, {approx}7 ps, {<=}5 Multiplication-Sign 10{sup 9} W/cm{sup 2}), where the laser photon energy is high enough to ionize 4d core electrons. In order to clarify how the innershell ionization followed by the Auger electron emission is affected under the intense laser irradiation, the electron energy distribution was measured. Photoelectron spectra showed that the peak position attributed to 4d hole shifted to lower energy and the spectral width was broadened with increasing cluster size. Moreover, the energy distribution exhibited that a strongly coupled cluster nanoplasma with several eV was generated.

Namba, S.; Hasegawa, N.; Kishimoto, M.; Nishikino, M.; Kawachi, T. [Graduate School of Engineering, Hiroshima University,Kagamiyama 1-4-1, Higashi-Hiroshima, Hiroshima, 739-8527 (Japan); Quantum Beam Science Directorate, Japan Atomic Energy Agency, Umemidai 8-1, Kizugawa, Kyoto, 619-0215 (Japan)

2012-07-11T23:59:59.000Z

66

ENERGY DISTRIBUTION OF TWO-ELECTRON IONIZATION OF HELIUM IN AN INTENSE LASER FIELD.  

DOE Green Energy (OSTI)

It is well known that a neutral atom interacting with a strong laser field will ionize at sufficiently high intensity even for photon energies well below the ionization threshold. When the required number of photons becomes very large, this process is best described by the suppression of the Coulomb barrier by the laser's oscillating electric field, allowing the electron to tunnel into the continuum. As the laser intensity is increased, more tightly bound electrons may be successively liberated by this mechanism. Such a sequential multiple ionization, long accepted as a reasonable approach to the formidable problem of a multielectron atom interacting nonperturbatively with an intense electromagnetic field, provides fair estimates of the various charge state appearance intensities while the tunneling rates are in excellent agreement with single ionization yields. However, more accurate measurements revealed systematic and very large deviations from the tunneling rates: near appearance intensity under standard experimental conditions, the observed double ion yield is several orders of magnitude larger than predicted by the sequential rate. It soon became clear that electrons could not be considered as independent and that electron-electron correlation had to be taken into account. Dynamic correlations have been considered in several theories. First qualitatively in the shakeoff model; then empirically through the e-2e cross-section in the quantum/classical three-step model (tunnel ionization, acceleration by the oscillating electric field and e-2e recollision with the ion); recently through the so-called intense field many-body-S-matrix theory and a purely empirical model of collective tunnel ionization. The validity of these ideas has been examined using numerical models. The measurement of total ion yields over a dynamic range exceeding ten orders of magnitude, a major breakthrough made possible by the availability of high-repetition rate lasers at the beginning of the 90's, was for a long time the only quantitative data to confront theory.

LAFON,R.; CHALOUPKA,J.L.; SHEEHY,B.; DIMAURO,L.F.; PAUL,P.M.; AGOSTINI,P.; KULANDER,K.C.

2000-09-24T23:59:59.000Z

67

Phase conjugation of high energy lasers.  

Science Conference Proceedings (OSTI)

In this report we explore claims that phase conjugation of high energy lasers by stimulated Brillouin scattering (SBS) can compensate optical aberrations associated with severely distorted laser amplifier media and aberrations induced by the atmosphere. The SBS media tested was a gas cell pressurized up to 300 psi with SF6 or Xe or both. The laser was a 10 Hz, 3J, Q-switched Nd:YAG with 25 ns wide pulses. Atmospheric aberrations were created with space heaters, helium jets and phase plates designed with a Kolmogorov turbulence spectrum characterized by a Fried parameter, ro , ranging from 0.6 - 6.0 mm. Phase conjugate tests in the laboratory were conducted without amplification. For the strongest aberrations, D/ro ~ 20, created by combining the space heaters with the phase plate, the Strehl ratio was degraded by a factor of ~50. Phase conjugation in SF6 restored the peak focusable intensity to about 30% of the original laser. Phase conjugate tests at the outdoor laser range were conducted with laser amplifiers providing gain in combination with the SBS cell. A large 600,000 BTU kerosene space heater was used to create turbulence along the beam path. An atmospheric structure factor of Cn2 = 5x10-13 m2/3 caused the illumination beam to expand to a diameter 250mm and overfill the receiver. The phase conjugate amplified return could successfully be targeted back onto glints 5mm in diameter. Use of a lenslet arrays to lower the peak focusable intensity in the SBS cell failed to produce a useful phase conjugate beam; The Strehl ratio was degraded with multiple random lobes instead of a single focus. I will review literature results which show how multiple beams can be coherently combined by SBS when a confocal reflecting geometry is used to focus the laser in the SBS cell.

Bliss, David Emery; Valley, Michael T.; Atherton, Briggs W.; Bigman, Verle; Boye, Lydia Ann; Broyles, Robin Scott; Kimmel, Mark W.; Law, Ryan J.; Yoder, James R.

2013-01-01T23:59:59.000Z

68

HIGH INTENSITY PERFORMANCE OF THE BROOKHAVEN AGS.  

SciTech Connect

The Brookhaven AGS provides 24 GeV protons for a multi-user program of fixed-target high energy physics experiments, such as the study of extremely rare Kaon decays. Up to 7 x 10{sup 13} protons are slowly extracted over 2.2 seconds each 5.1 seconds. The muon storage ring of the g-2 experiment is supplied with bunches of 7 x 10{sup 12} protons. Since the completion of the a 1.9 GeV Booster synchrotron and installation of a new high-power rf system and transition jump system in the AGS various modes of operation have been explored to overcome space charge limits and beam instabilities at these extreme beam intensities. Experiments have been done using barrier cavities to enable accumulation of debunched beam in the AGS as a potential path to significantly higher intensities. We report on the present understanding of intensity limitations and prospects for overcoming them.

AHRENS,L.A.; ALESSI,J.; BLASKIEWICZ,M.; BRENNAN,J.M.; BROWN,K.; GARDNER,C.; GLENN,J.W.; ROSER,T.; SMITH,K.S.; VAN ASSELT,W.; ZHANG,S.Y.

1999-03-29T23:59:59.000Z

69

Resonant Auger Effect at High X-Ray Intensity  

SciTech Connect

The resonant Auger effect of atomic neon exposed to high-intensity x-ray radiation in resonance with the 1s {yields} 3p transition is discussed. High intensity here means that the x-ray peak intensity is sufficient ({approx} 10{sup 18} W/cm{sup 2}) to induce Rabi oscillations between the neon ground state and the 1s{sup -1}3p ({sup 1}P) state within the relaxation lifetime of the inner-shell vacancy. For the numerical analysis presented, an effective two-level model, including a description of the resonant Auger decay process, is employed. Both coherent and chaotic x-ray pulses are treated. The latter are used to simulate radiation from x-ray free-electron lasers based on the principle of self-amplified spontaneous emission. Observing x-ray-driven atomic population dynamics in the time domain is challenging for chaotic pulse ensembles. A more practical option for experiments using x-ray free-electron lasers is to measure the line profiles in the kinetic energy distribution of the resonant Auger electron. This provides information on both atomic population dynamics and x-ray pulse properties.

Rohringer, N; Santra, R

2008-03-27T23:59:59.000Z

70

AGS RESONANT EXTRACTION WITH HIGH INTENSITY BEAMS.  

SciTech Connect

The Brookhaven AGS third integer resonant extraction system allows the AGS to provide high quality, high intensity 25.5 GeV/c proton beams simultaneously to four target stations and as many as 8 experiments. With the increasing intensities (over 7 x 10{sup 13} protons/pulse) and associated longer spill periods (2.4 to 3 seconds long), we continue to run with low losses and high quality low modulation continuous current beams.[1] Learning to extract and transport these higher intensity beams has required a process of careful modeling and experimentation. We have had to learn how to correct for various instabilities and how to better match extraction and the transport lines to the higher emittance beams being accelerated in the AGS. Techniques employed include ''RF'' methods to smooth out momentum distributions and fine structure. We will present results of detailed multi-particle tracking modeling studies which enabled us to develop a clear understanding of beam loss mechanisms in the transport and extraction process. We will report on our status, experiences, and the present understanding of the intensity limitations imposed by resonant extraction and transport to fixed target stations.

AHRENS,L.; BROWN,K.; GLENN,J.W.; ROSER,T.; TSOUPAS,N.; VANASSELT,W.

1999-03-29T23:59:59.000Z

71

Interaction of High Intensity Electromagnetic Waves with Plasmas  

SciTech Connect

The focus of our work during the duration of this grant was on the following areas: (a) the fundamental plasma physics of intense laser-plasma interactions, including the nonlinear excitation of plasma waves for accelerator applications, as well as the recently discovered by us phenomenon of the relativistic bi-stability of relativistic plasma waves driven by a laser beatwave; (b) interaction of high power microwave beams with magnetized plasma, including some of the recently discovered by us phenomena such as the Undulator Induced Transparency (UIT) as well as the new approaches to dynamic manipulation of microwave pulses; (c) investigations of the multi-color laser pulse interactions in the plasma, including the recently discovered by us phenomenon of Electromagnetic Cascading (EC) and the effect of the EC of three-dimensional dynamics of laser pulses (enhanced/suppressed selffocusing etc.); (d) interaction of high-current electron beams with the ambient plasma in the context of Fast Ignitor (FI) physics, with the emphasis on the nonlinear dynamics of the Weibel instability and beam filamentation.

G. Shvets

2008-10-03T23:59:59.000Z

72

REFLECTED LIGHT INTENSITY DISTRIBUTIONS FROM DEFECTS ON HIGHLY REFLECTIVE SPHERES PDO 6984778, Topical Report  

SciTech Connect

A light reflection technique suitable for development into an automated surface quality certification system was investigated to determine if reflected light intensity distributions could be corre]ated with surface defect depths. Reflected laser light intensity distributions from pit and scratch defects on highly reflective spheres were studied with a commercial multi-element photodetector. It was found that the intensity distributions --Goll'lf be correlated with depths of pits and scratches in a size range of concern on highly reflective' spheres.

Klingsport, P. E.

1977-02-01T23:59:59.000Z

73

Electronic High-Intensity Discharge Lighting  

Science Conference Proceedings (OSTI)

This EPRI Technical Update addresses the most promising controllable energy efficient light source electronic high-intensity discharge (HID) lighting. Business and technical market factors (Chapter 2) explain the upcoming growth of the HID lamp and electronic HID ballast market. Future technical improvements are emphasized along with discussion of the importance of utility involvement in helping their customers make the switch from magnetically-ballasted HID lighting to higher efficiency electronic HID l...

2007-12-21T23:59:59.000Z

74

Higher order terms of radiative damping in extreme intense laser-matter interaction  

Science Conference Proceedings (OSTI)

The higher order terms of the Lorentz-Abraham-Dirac equation have been derived, and their effects are studied via a relativistic collisional particle-in-cell simulation. The dominant group of terms up to the fourth order of the Lorentz-Abraham-Dirac equation is identified for ultra-intense laser-matter interactions. The second order terms are found to be the damping terms of the Lorentz force while the first order terms represent friction in the equation of motion. Because the second order terms restrict electron acceleration during the laser interaction, electrons/ions are prevented from over-accelerating. Radiative damping becomes highly significant when I{>=} 10{sup 22} W/cm{sup 2} while Bremsstrahlung will be saturated, thus radiative damping will be a dominant source of hard x-rays in regimes at extreme intensities.

Pandit, Rishi R.; Sentoku, Yasuhiko [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States)

2012-07-15T23:59:59.000Z

75

Fiber Laser Front Ends for High Energy, Short Pulse Lasers  

SciTech Connect

We are developing a fiber laser system for short pulse (1-10ps), high energy ({approx}1kJ) glass laser systems. Fiber lasers are ideal for these systems as they are highly reliable and enable long term stable operation.

Dawson, J; Messerly, M; Phan, H; Siders, C; Beach, R; Barty, C

2007-06-21T23:59:59.000Z

76

High intensity discharge device containing oxytrihalides  

DOE Patents (OSTI)

A fill composition for a high intensity discharge device including mercury, niobium oxytrihalide, and a molecular stabilization agent is provided. The molar ratio of niobium oxytrihalide to the molecular stabilization agent in the fill is in the range of from about 5:1 to about 7.5:1. Niobium oxytrihalide is present in the fill in sufficient amount to produce, by dissociation in the discharge, atomic niobium, niobium oxide, NbO, and niobium dioxide, NbO.sub.2, with the molar ratio of niobium-containing vapor species to mercury in the fill being in the range of from about 0.01:1 to about 0.50:1; and mercury pressure of about 1 to about 50 atmospheres at lamp operating temperature. There is also provided a high intensity discharge device comprising a sealed light-transmissive arc tube; the arc tube including the above-described fill; and an energizing means for producing an electric discharge within the arc tube.

Lapatovich, Walter P. (Hudson, MA); Keeffe, William M. (Rockport, MA); Liebermann, Richard W. (Danvers, MA); Maya, Jakob (Brookline, MA)

1987-01-01T23:59:59.000Z

77

High intensity discharge device containing oxytrihalides  

DOE Patents (OSTI)

A fill composition for a high intensity discharge device including mercury, niobium oxytrihalide, and a molecular stabilization agent is provided. The molar ratio of niobium oxytrihalide to the molecular stabilization agent in the fill is in the range of from about 5:1 to about 7.5:1. Niobium oxytrihalide is present in the fill in sufficient amount to produce, by dissociation in the discharge, atomic niobium, niobium oxide, NbO, and niobium dioxide, NbO[sub 2], with the molar ratio of niobium-containing vapor species to mercury in the fill being in the range of from about 0.01:1 to about 0.50:1; and mercury pressure of about 1 to about 50 atmospheres at lamp operating temperature. There is also provided a high intensity discharge device comprising a sealed light-transmissive arc tube; the arc tube including the above-described fill; and an energizing means for producing an electric discharge within the arc tube. 7 figs.

Lapatovich, W.P.; Keeffe, W.M.; Liebermann, R.W.; Maya, J.

1987-06-09T23:59:59.000Z

78

An intensity-modulated dual-wavelength He-Ne laser for remote sensing of methane  

SciTech Connect

The differential absorption laser radar for methane sensing detects a leakage of methane gas by emitting into the atmosphere the light of a wavelength absorbable by methane, receiving the light returning after being reflected or scattered on a road or wall surface, etc., and measuring the light intensity lost during the travel. This methane detection system is highly practicable as it makes an instantaneous remote detection possible. The authors have developed a new He-Ne laser that could be used as the light source for the above system. This device emits a two-wavelength laser beam (one wavelength absorbable by methane and the other not absorbable by methane but used for referential purposes) from a single plasma tube, and there is no possibility of the axes of the two-wavelength component deviating from each other. Further, using this laser, they have developed a vehicle-mounted type differential absorption laser radar system which has successfully detected low density methane leakage while the vehicle was moving.

Ueki, T.; Tanaka, H.; Uehara, K.

1988-01-01T23:59:59.000Z

79

Optical Fiber High Temperature Sensor Instrumentation for Energy Intensive Industries  

SciTech Connect

This report summarizes technical progress during the program “Optical Fiber High Temperature Sensor Instrumentation for Energy Intensive Industries”, performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The objective of this program was to use technology recently invented at Virginia Tech to develop and demonstrate the application of self-calibrating optical fiber temperature and pressure sensors to several key energy-intensive industries where conventional, commercially available sensors exhibit greatly abbreviated lifetimes due primarily to environmental degradation. A number of significant technologies were developed under this program, including • a laser bonded silica high temperature fiber sensor with a high temperature capability up to 700°C and a frequency response up to 150 kHz, • the world’s smallest fiber Fabry-Perot high temperature pressure sensor (125 x 20 ?m) with 700°C capability, • UV-induced intrinsic Fabry-Perot interferometric sensors for distributed measurement, • a single crystal sapphire fiber-based sensor with a temperature capability up to 1600°C. These technologies have been well demonstrated and laboratory tested. Our work plan included conducting major field tests of these technologies at EPRI, Corning, Pratt & Whitney, and Global Energy; field validation of the technology is critical to ensuring its usefulness to U.S. industries. Unfortunately, due to budget cuts, DOE was unable to follow through with its funding commitment to support Energy Efficiency Science Initiative projects and this final phase was eliminated.

Cooper, Kristie L.; Wang, Anbo; Pickrell, Gary R.

2006-11-14T23:59:59.000Z

80

High Energy Laser Diagnostic Sensors  

Science Conference Proceedings (OSTI)

Recent advancements in high energy laser (HEL) sources have outpaced diagnostic tools capable of accurately quantifying system performance. Diagnostic tools are needed that allow system developers to measure the parameters that define HEL effectiveness. The two critical parameters for quantifying HEL effectiveness are the irradiance on target and resultant rise in target temperature. Off-board sensing has its limitations, including unpredictable changes in the reflectivity of the target, smoke and outgassing, and atmospheric distortion. On-board sensors overcome the limitations of off-board techniques but must survive high irradiance levels and extreme temperatures.We have developed sensors for on-target diagnostics of high energy laser beams and for the measurement of the thermal response of the target. The conformal sensors consist of an array of quantum dot photodetectors and resistive temperature detectors. The sensor arrays are lithographically fabricated on flexible substrates and can be attached to a variety of laser targets. We have developed a nanoparticle adhesive process that provides good thermal contact with the target and that ensures the sensor remains attached to the target for as long as the target survives. We have calibrated the temperature and irradiance sensors and demonstrated them in a HEL environment.

Luke, James R.; Goddard, Douglas N.; Thomas, David [AEgis Technologies Group, 10501 Research Rd SE, Suite D, Albuquerque, NM 87123, 505-938-9221 (United States); Lewis, Jay [RTI International, Research Triangle Park, NC (United States)

2010-10-08T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" 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

Apparatus and process for active pulse intensity control of laser beam  

DOE Patents (OSTI)

An optically controlled laser pulse energy control apparatus and process is disclosed wherein variations in the energy of a portion of the laser beam are used to vary the resistance of a photodetector such as a photoresistor through which a control voltage is fed to a light intensity controlling device through which a second portion of the laser beam passes. Light attenuation means are provided to vary the intensity of the laser light used to control the resistance of the photodetector. An optical delay path is provided through which the second portion of the beam travels before reaching the light intensity controlling device. The control voltage is supplied by a variable power supply. The apparatus may be tuned to properly attenuate the laser beam passing through the intensity controlling device by adjusting the power supply, the optical delay path, or the light attenuating means. 3 figs.

Wilcox, R.B.

1990-01-01T23:59:59.000Z

82

Apparatus and process for active pulse intensity control of laser beam  

SciTech Connect

An optically controlled laser pulse energy control apparatus and process is disclosed wherein variations in the energy of a portion of the laser beam are used to vary the resistance of a photodetector such as a photoresistor through which a control voltage is fed to a light intensity controlling device through which a second portion of the laser beam passes. Light attenuation means are provided to vary the intensity of the laser light used to control the resistance of the photodetector. An optical delay path is provided through which the second portion of the beam travels before reaching the light intensity controlling device. The control voltage is supplied by a variable power supply. The apparatus may be tuned to properly attenuate the laser beam passing through the intensity controlling device by adjusting the power supply, the optical delay path, or the light attenuating means.

Wilcox, Russell B. (Oakland, CA)

1992-01-01T23:59:59.000Z

83

Apparatus and process for active pulse intensity control of laser beam  

DOE Patents (OSTI)

An optically controlled laser pulse energy control apparatus and process is disclosed wherein variations in the energy of a portion of the laser beam are used to vary the resistance of a photodetector such as a photoresistor through which a control voltage is fed to a light intensity controlling device through which a second portion of the laser beam passes. Light attenuation means are provided to vary the intensity of the laser light used to control the resistance of the photodetector. An optical delay path is provided through which the second portion of the beam travels before reaching the light intensity controlling device. The control voltage is supplied by a variable power supply. The apparatus may be tuned to properly attenuate the laser beam passing through the intensity controlling device by adjusting the power supply, the optical delay path, or the light attenuating means. 3 figs.

Wilcox, R.B.

1990-12-31T23:59:59.000Z

84

HOT ELECTRON ENERGY DISTRIBUTIONS FROM ULTRA-INTENSE LASER SOLID INTERACTIONS  

SciTech Connect

We present experimental data of electron energy distributions from ultra-intense (>10{sup 19} W/cm{sup 2}) laser-solid interactions using the Rutherford Appleton Laboratory Vulcan petawatt laser. These measurements were made using a CCD-based magnetic spectrometer. We present details on the distinct effective temperatures that were obtained for a wide variety of targets as a function of laser intensity. It is found that as the intensity increases from 10{sup 17} W/cm{sup 2} to 10{sup 19} W/cm{sup 2}, a 0.4 dependence on the laser intensity is found. Between 10{sup 19} W/cm{sup 2} and 10{sup 20} W/cm{sup 2}, a gradual rolling off of temperature with intensity is observed.

Chen, H; Wilks, S C; Kruer, W L; Moon, S; Patel, N; Patel, P K; Shepherd, R; Snavely, R

2005-12-08T23:59:59.000Z

85

Laser Guiding for GeV Laser-Plasma Accelerators  

E-Print Network (OSTI)

Light pipe for high intensity laser pulses. Phys. Rev. Lett.and relativistically strong laser pulses in an underdensefrom Thomson scat- tering using laser wake?eld accelerators.

Leemans, Wim; Esarey, Eric; Geddes, Cameron; Schroeder, C.B.; Toth, Csaba

2005-01-01T23:59:59.000Z

86

Scaling to Ultra-High Intensities by High-Energy Petawatt Beam Combining  

SciTech Connect

The output pulse energy from a single-aperture high-energy laser amplifier (e.g. fusion lasers such as NIF and LMJ) are critically limited by a number of factors including optical damage, which places an upper bound on the operating fluence; parasitic gain, which limits together with manufacturing costs the maximum aperture size to {approx} 40-cm; and non-linear phase effects which limits the peak intensity. For 20-ns narrow band pulses down to transform-limited sub-picosecond pulses, these limiters combine to yield 10-kJ to 1-kJ maximum pulse energies with up to petawatt peak power. For example, the Advanced Radiographic Capability (ARC) project at NIF is designed to provide kilo-Joule pulses from 0.75-ps to 50-ps, with peak focused intensity above 10{sup 19} W/cm{sup 2}. Using such a high-energy petawatt (HEPW) beamline as a modular unit, they discuss large-scale architectures for coherently combining multiple HEPW pulses from independent apertures, called CAPE (Coherent Addition of Pulses for Energy), to significantly increase the peak achievable focused intensity. Importantly, the maximum intensity achievable with CAPE increases non-linearly. Clearly, the total integrated energy grows linearly with the number of apertures N used. However, as CAPE combines beams in the focal plane by increasing the angular convergence to focus (i.e. the f-number decreases), the foal spot diameter scales inversely with N. Hence the peak intensity scales as N{sup 2}. Using design estimates for the focal spot size and output pulse energy (limited by damage fluence on the final compressor gratings) versus compressed pulse duration in the ARC system, Figure 2 shows the scaled focal spot intensity and total energy for various CAPE configurations from 1,2,4, ..., up to 192 total beams. They see from the fixture that the peak intensity for event modest 8 to 16 beam combinations reaches the 10{sup 21} to 10{sup 22} W/cm{sup 2} regime. With greater number of apertures, or with improvements to the focusability of the individual beams, the maximum peak intensity can be increased further to {approx} 10{sup 24} W/cm{sup 2}. Lastly, an important feature of the CAPE architecture is the ability to coherently combine beams to produce complex spatio-temporal intensity distributions for laser-based accelerators (e.g. all-optical electron injection and acceleration) and high energy density science applications such as fast ignition.

Siders, C W; Jovanovic, I; Crane, J; Rushford, M; Lucianetti, A; Barty, C J

2006-06-23T23:59:59.000Z

87

High-Energy Laser Ponderomotive Acceleration  

SciTech Connect

A new concept of TeV-range laser ponderomotive acceleration in a plasma is proposed. Particles are accelerated in the point-like scattering by the leading front of the laser pulse, propagating at the group velocity less than the vacuum speed of light. In this scheme, the gain in particle energy is determined by the group velocity and does not depend on laser intensity, which determines the quantum probability of acceleration. The quantum and classical analysis of the scheme proposed is presented. Estimates show that the concept proposed is a promising technique for compact laser acceleration of TeV energy range.

Smetanin, I.V.; /Lebedev Inst.; Barnes, C.; /SLAC; Nakajima, K.; /KEK, Tsukuba

2006-03-10T23:59:59.000Z

88

Controlling double ionization of atoms in an intense bichromatic laser pulse  

SciTech Connect

We consider the classical dynamics of a two-electron system subjected to an intense bichromatic linearly polarized laser pulse. By varying the parameters of the field, such as the phase lag and the relative amplitude between the two colors of the field, we observe several trends from the statistical analysis of a large ensemble of trajectories initially in the ground-state energy of the helium atom: high sensitivity of the sequential double-ionization component, low sensitivity of the intensities where nonsequential double ionization occurs, while the corresponding yields can vary drastically. All these trends hold irrespective of which parameter is varied: the phase lag or the relative amplitude. We rationalize these observations by an analysis of the phase-space structures that drive the dynamics of this system and determine the extent of double ionization. These trends turn out to be mainly regulated by the dynamics of the inner electron.

Kamor, A.; Uzer, T. [School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332-0430 (United States); Mauger, F.; Chandre, C. [Centre de Physique Theorique, CNRS, Aix-Marseille Universite, Campus de Luminy, case 907, 13288 Marseille cedex 09 (France)

2011-03-15T23:59:59.000Z

89

Intensity-resolved Above Threshold Ionization Yields of Atoms with Ultrashort Laser Pulses  

E-Print Network (OSTI)

The above threshold ionization (ATI) spectra provide a diversity of information about a laser-atom ionization process such as laser intensity, pulse duration, carrier envelope phase, and atomic energy level spacing. However, the spatial distribution of intensities inherent in all laser beams reduces the resolution of this information. This research focuses on recovering the intensity-resolved ATI spectra from experimental data using a deconvolution algorithm. Electron ionization yields of xenon were measured for a set of laser pulse intensities using a time of flight (TOF) setup. Horizontally polarized, unchirped, 50fs pulses were used in the ionization process. All laser parameters other than the radiation intensity were held constant over the set of intensity measurements. A deconvolution algorithm was developed based on the experimental parameters. Then the deconvolution algorithm was applied to the experimental data to obtain the intensity-resolved total yield probability and ATI spectra. Finally, an error analysis was performed to determine the stability and accuracy of the algorithm as well as the quality of the data. It was found that the algorithm produced greater contrast for peaks in the ATI spectra where atom specific resonant behavior is observed. Additionally, the total yield probability showed that double ionization may be observed in the ionization yield. The error analysis revealed that the algorithm was stable under the experimental conditions for a range of intensities.

Hart, Nathan Andrew

2011-08-01T23:59:59.000Z

90

Intensity-dependent enhancements in high-order above-threshold ionization  

Science Conference Proceedings (OSTI)

The very pronounced intensity-dependent enhancements of groups of peaks of high-order above-threshold-ionization spectra of rare-gas atoms are investigated using an improved version of the strong-field approximation, which realistically models the respective atom. Two types of enhancements are found and explained in terms of constructive interference of the contributions of a large number of long quantum orbits. The first type is observed for intensities slightly below channel closings. Its intensity dependence is comparatively smooth and it is generated by comparatively few (of the order of 20) orbits. The second type occurs precisely at channel closings and exhibits an extremely sharp intensity dependence. It requires constructive interference of a very large number of long orbits (several hundreds) and generates cusps in the electron spectrum at integer multiples of the laser-photon energy. An interpretation of these enhancements as a threshold phenomenon is also given. An interplay of different types of the threshold anomalies is observed. The position of both types of enhancements, in the photoelectron-energy--laser-intensity plane, shifts to the next channel closing intensity with the change of the ground-state parity. The enhancements gradually disappear with decreasing laser pulse duration. This confirms the interpretation of enhancements as a consequence of the interference of long strong-laser-field-induced quantum orbits.

Milosevic, D. B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany); Hasovic, E.; Gazibegovic-Busuladzic, A. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo, Bosnia and Herzegovina (Bosnia and Herzegowina); Busuladzic, M. [Medical Faculty, University of Sarajevo, Cekalusa 90, 71000 Sarajevo (Bosnia and Herzegowina); Becker, W. [Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany)

2007-11-15T23:59:59.000Z

91

On the control of filamentation of intense laser beams propagating in underdense plasma  

SciTech Connect

In indirect drive ICF ignition designs, the laser energy is delivered into the hohlraum through the laser entrance holes (LEH), which are sized as small as practicable to minimize X-ray radiation losses. On the other hand, deleterious laser plasma processes, such as filamentation and stimulated back-scatter, typically increase with laser intensity. Ideally, therefore, the laser spot shape should be a close fit to the LEH, with uniform (envelope) intensity in the spot and minimal energy at larger radii spilling onto the LEH material. This keeps the laser intensity as low as possible consistent with the area of the LEH aperture and the power requirements of the design. This can be achieved (at least for apertures significantly larger than the laser's aberrated focal spot) by the use of custom-designed phase plates. However, outfitting the 192 beam (National Ignition facility) NIF laser with multiple sets of phase plates optimized for a variety of different LEH aperture sizes is an expensive proposition. It is thus important to assess the impact on laser-plasma interaction processes of using phase plates with a smaller than optimum focal spot (or even no phase plates at all!) and then de-focusing the beam to expand it to fill the LEH and lower its intensity. We find significant effects from the lack of uniformity of the laser envelope out of the focal plane, from changes in the characteristic sizes of the laser speckle, and on the efficacy of additional polarization and/or SSD beam smoothing. We quantify these effects with analytic estimates and simulations using our laser plasma interaction code pF3D.

Williams, E A

2005-10-21T23:59:59.000Z

92

High-Intensity Discharge Lighting Basics | Department of Energy  

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

High-Intensity Discharge Lighting Basics High-Intensity Discharge Lighting Basics High-Intensity Discharge Lighting Basics August 15, 2013 - 5:59pm Addthis High-intensity discharge (HID) lighting provides the highest efficacy and longest service life of any lighting type. It can save 75%-90% of lighting energy when it replaces incandescent lighting. Illustration of a high-intensity discharge (HID) lIllustration amp. The lamp is a tall cylindrical shape, and a cutout of the outer tube shows the materials inside. A long, thin cylinder called the arc tube runs through the lamp between two electrodes. The space around the arc tube is labeled as a vacuum. In a high-intensity discharge lamp, electricity arcs between two electrodes, creating an intensely bright light. Mercury, sodium, or metal halide gas

93

HIGH INTENSITY BEAM OPERATION OF THE BROOKHAVEN AGS  

SciTech Connect

For the last few years the Brookhaven AGS has operated at record proton intensities. This high beam intensity allowed for the simultaneous operation of several high precision rare kaon decay experiments. The record beam intensities were achieved after the AGS Booster was commissioned and a transition jump system, a powerful transverse damper, and an rf upgrade in the AGS were completed. The intensity is presently limited by space charge effects at both Booster and AGS injection and transverse instabilities in the AGS.

ROSER,T.

1999-06-28T23:59:59.000Z

94

Compact and highly efficient laser pump cavity  

SciTech Connect

A new, compact, side-pumped laser pump cavity design which uses non-conventional optics for injection of laser-diode light into a laser pump chamber includes a plurality of elongated light concentration channels. In one embodiment, the light concentration channels are compound parabolic concentrators (CPC) which have very small exit apertures so that light will not escape from the pumping chamber and will be multiply reflected through the laser rod. This new design effectively traps the pump radiation inside the pump chamber that encloses the laser rod. It enables more uniform laser pumping and highly effective recycle of pump radiation, leading to significantly improved laser performance. This new design also effectively widens the acceptable radiation wavelength of the diodes, resulting in a more reliable laser performance with lower cost.

Chang, Jim J. (Dublin, CA); Bass, Isaac L. (Castro Valley, CA); Zapata, Luis E. (Livermore, CA)

1999-01-01T23:59:59.000Z

95

Compact and highly efficient laser pump cavity  

SciTech Connect

A new, compact, side-pumped laser pump cavity design which uses non-conventional optics for injection of laser-diode light into a laser pump chamber includes a plurality of elongated light concentration channels. In one embodiment, the light concentration channels are compound parabolic concentrators (CPC) which have very small exit apertures so that light will not escape from the pumping chamber and will be multiply reflected through the laser rod. This new design effectively traps the pump radiation inside the pump chamber that encloses the laser rod. It enables more uniform laser pumping and highly effective recycle of pump radiation, leading to significantly improved laser performance. This new design also effectively widens the acceptable radiation wavelength of the diodes, resulting in a more reliable laser performance with lower cost.

Chang, J.J.; Bass, I.L.; Zapata, L.E.

1999-11-02T23:59:59.000Z

96

Performances of BNL high-intensity synchrotrons  

SciTech Connect

The AGS proton synchrotron was completed in 1960 with initial intensity in the 10 to the 10th power proton per pulse (ppp) range. Over the years, through many upgrades and improvements, the AGS now reached an intensity record of 6.3 {times} 10{sup 13} ppp, the highest world intensity record for a proton synchrotron on a single pulse basis. At the same time, the Booster reached 2.2 {times} 10{sup 13} ppp surpassing the design goal of 1.5 {times} 10{sup 13} ppp due to the introduction of second harmonic cavity during injection. The intensity limitation caused by space charge tune spread and its relationship to injection energy at 50 MeV, 200 MeV, and 1,500 MeV will be presented as well as many critical accelerator manipulations. BNL currently participates in the design of an accumulator ring for the SNS project at Oak Ridge. The status on the issues of halo formation, beam losses and collimation are also presented.

Weng, W.T.

1998-03-01T23:59:59.000Z

97

Asymmetric explosion of clusters in intense laser fields  

Science Conference Proceedings (OSTI)

We examine asymmetric expansion of argon clusters illuminated by 800 nm laser pulses of duration Almost-Equal-To 23fs, using three-dimensional particle-in-cell (PIC) simulation. For this short pulse duration, laser energy absorption by cluster electrons is dominated by the nonlinear resonance (NLR) absorption process [Phys. Rev. Lett. 96, 123401 (2006)]. In this work, we concentrate, particularly, on the ionic outcome in the NLR regime and show that higher charge states of argon ions are produced along the laser polarization than in the transverse directions leading to the anisotropy (asymmetry) in the ion energy distribution. This anisotropy already established during the short pulse duration (or in the early duration of a long pulse) may contribute to the anisotropic ion emission reported in cluster experiments with pulse duration longer than 100 fs. Our PIC results are compared with a charged-sphere model showing that cluster explosion is mainly due to Coulomb repulsion between the cluster ions.

Kundu, M. [Institute for Plasma Research, Bhat, Gandhinagar 382 428, Gujarat (India)

2012-08-15T23:59:59.000Z

98

Ultrahigh-intensity laser: physics of the extreme on a tabletop  

SciTech Connect

This paper reviews the development of ultrahigh-intensity laser technology from the early 1960`s to the present, explaining the obstacles to each increase in intensity and the technical means used to overcome them. These included the shortening of pulses, mode locking, and chirped pulse amplification (CPA). The particular technical advances that make CPA possible included the invention of matched pulse stretchers and compressors and the development of ultrabroadband gain media. The paper then discusses the generation of ultrashort pulses and their characteristics. It then moves on to the Petawatt laser, which incorporates the CPA technology. It then addresses the question of whether it is possible to forecast the ultimate peak power that can be achieved by a laser system of a given size. Applications of ultrahigh-intensity lasers in different physical regimes are discussed.

Mourou, G.A.; Barty, C.P.; Perry, M.D.

1997-10-10T23:59:59.000Z

99

Acceleration of electrons by a circularly polarized laser pulse in the presence of an intense axial magnetic field in vacuum  

Science Conference Proceedings (OSTI)

Acceleration of electrons by a circularly polarized laser pulse in the presence of a short duration intense axial magnetic field has been studied. Resonance occurs between the electrons and the laser field for an optimum magnetic field leading to effective energy transfer from laser to electrons. The value of optimum magnetic field is independent of the laser intensity and decreases with initial electron energy. The electrons rotate around the axis of the laser pulse with small angle of emittance and small energy spread. Acceleration gradient increases with laser intensity and decreases with initial electron energy.

Singh, K. P. [Computational Plasma Dynamics Laboratory, Kettering University, Flint, Michigan 48504 (United States)

2006-08-15T23:59:59.000Z

100

HOT ELECTRON ENERGY DISTRIBUTIONS FROM ULTRA-INTENSE LASER SOLID INTERACTIONS  

Science Conference Proceedings (OSTI)

Measurements of electron energy distributions from ultra-intense (>10{sup 19} W/cm{sup 2}) laser-solid interactions using an electron spectrometer are presented. These measurements were performed on the Vulcan petawatt laser at Rutherford Appleton Laboratory and the Callisto laser at Lawrence Livermore National Laboratory. The effective hot electron temperatures (T{sub hot}) have been measured for laser intensities (I{lambda}{sup 2}) from 10{sup 18} W/cm{sup 2} {micro}m{sup 2} to 10{sup 21} W/cm{sup 2} {micro}m{sup 2} for the first time, and T{sub hot} is found to increase as (I{lambda}{sup 2}){sup 0.34} {+-} 0.4. This scaling agrees well with the empirical scaling published by Beg et al. (1997), and is explained by a simple physical model that gives good agreement with experimental results and particle-in-cell simulations.

Chen, H; Wilks, S C; Kruer, W; Patel, P; Shepherd, R

2008-10-08T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" from the National Library of EnergyBeta (NLEBeta).
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101

High power regenerative laser amplifier  

DOE Patents (OSTI)

A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse.

Miller, John L. (Livermore, CA); Hackel, Lloyd A. (Livermore, CA); Dane, Clifford B. (Dublin, CA); Zapata, Luis E. (Livermore, CA)

1994-01-01T23:59:59.000Z

102

High power regenerative laser amplifier  

DOE Patents (OSTI)

A regenerative amplifier design capable of operating at high energy per pulse, for instance, from 20-100 Joules, at moderate repetition rates, for instance from 5-20 Hertz is provided. The laser amplifier comprises a gain medium and source of pump energy coupled with the gain medium; a Pockels cell, which rotates an incident beam in response to application of a control signal; an optical relay system defining a first relay plane near the gain medium and a second relay plane near the rotator; and a plurality of reflectors configured to define an optical path through the gain medium, optical relay and Pockels cell, such that each transit of the optical path includes at least one pass through the gain medium and only one pass through the Pockels cell. An input coupler, and an output coupler are provided, implemented by a single polarizer. A control circuit coupled to the Pockels cell generates the control signal in timed relationship with the input pulse so that the input pulse is captured by the input coupler and proceeds through at least one transit of the optical path, and then the control signal is applied to cause rotation of the pulse to a polarization reflected by the polarizer, after which the captured pulse passes through the gain medium at least once more and is reflected out of the optical path by the polarizer before passing through the rotator again to provide an amplified pulse. 7 figures.

Miller, J.L.; Hackel, L.A.; Dane, C.B.; Zapata, L.E.

1994-02-08T23:59:59.000Z

103

High intensity performance and upgrades at the Brookhaven AGS  

SciTech Connect

For the last two years the Brookhaven AGS has operated the slow extracted beam program at record proton intensities. This high beam intensity allowed for the simultaneous operation of three high precision rare kaon decay experiments. The record beam intensities were achieved after the 1.5 GeV Booster was commissioned and a transition jump system, a powerful transverse damper, and an rf upgrade in the AGS were completed. Recently even higher intensity proton synchrotrons are studied for neutron spallation sources or proton driver for a muon collider. Implications of the experiences from the AGS to these proposals and also possible future upgrades for the AGS are discussed.

Roser, T.

1996-12-31T23:59:59.000Z

104

Scientific applications for high-energy lasers  

Science Conference Proceedings (OSTI)

The convergence of numerous factors makes the time ripe for the development of a community of researchers to use the high-energy laser for scientific investigations. This document attempts to outline the steps necessary to access high-energy laser systems and create a realistic plan to implement usage. Since an academic/scientific user community does not exist in the USA to any viable extent, we include information on present capabilities at the Nova laser. This will briefly cover laser performance and diagnostics and a sampling of some current experimental projects. Further, to make the future possibilities clearer, we will describe the proposed next- generation high-energy laser, named for its inertial fusion confinement (ICF) goal, the multi-megaJoule, 500-teraWatt National Facility, or NIF.

Lee, R.W. [comp.

1994-03-01T23:59:59.000Z

105

Comoving acceleration of overdense electron-positron plasma by colliding ultra-intense laser pulses  

Science Conference Proceedings (OSTI)

Particle-in-cell (PIC) simulation results of sustained acceleration of electron-positron (e+e-) plasmas by comoving electromagnetic (EM) pulses are presented. When a thin slab of overdense e+e- plasma is irradiated with linear-polarized ultra-intense short laser pulses from both sides, the pulses are transmitted when the plasma is compressed to thinner than {approx}2 relativistic skin depths. A fraction of the plasma is then captured and efficiently accelerated by self-induced JxB forces. For 1 {mu}m laser and 10{sup 21} W cm{sup -2} intensity, the maximum energy exceeds GeV in a picosecond.

Liang, Edison [Rice University, P.O. Box 1892, Houston, Texas 77251 (United States)

2006-06-15T23:59:59.000Z

106

Tailoring the filamentation of intense femtosecond laser pulses with periodic lattices  

Science Conference Proceedings (OSTI)

We show numerically that by using periodic lattices the filamentation of intense femtosecond laser pulses, otherwise a result of competing nonlinear effects, can be well controlled with respect to its properties. The diffraction induced by the lattice provides a regularizing mechanism to the nonlinear self-action effects involved in filamentation. We demonstrate a new propagation regime of intense lattice solitons bridging the field of spatial solitons with that of femtosecond laser filamentation. The effective filamentation control is expected to have an important impact on numerous applications.

Panagiotopoulos, P.; Tzortzakis, S. [Institute of Electronic Structure and Laser, Foundation for Research and Technology Hellas, P.O. Box 1527, GR-71110 Heraklion (Greece); Efremidis, N. K. [Department of Applied Mathematics, University of Crete, P.O. Box 2208, GR-71003 Heraklion (Greece); Papazoglou, D. G. [Institute of Electronic Structure and Laser, Foundation for Research and Technology Hellas, P.O. Box 1527, GR-71110 Heraklion (Greece); Department of Materials Science and Technology, University of Crete, P.O. Box 2208, GR-71003 Heraklion (Greece); Couairon, A. [Centre de Physique Theorique, Centre National de la Recherche Scientifique, Ecole Polytechnique, F-91128 Palaiseau (France)

2010-12-15T23:59:59.000Z

107

Momentum distributions of sequential ionization generated by an intense laser pulse  

E-Print Network (OSTI)

The relative yield and momentum distributions of all multiply charged atomic ions generated by a short (30 fs) intense (10(14)-5 x 10(18) W/cm(2)) laser pulse are investigated using a Monte Carlo simulation. We predict a substantial shift in the maximum (centroid) of the ion-momentum distribution along the laser polarization as a function of the absolute phase. This effect should be experimentally detectable with currently available laser systems even for relatively long pulses, such as 25-30 fs. In addition to the numerical results, we present semianalytical scaling for the position of the maximum.

Shvetsov-Shilovski, N. I.; Sayler, A. M.; Rathje, T.; Paulus, Gerhard G.

2011-01-01T23:59:59.000Z

108

Analysis of a laser induced plasma in high pressure SF6 gas for high-voltage, high-current switching.  

E-Print Network (OSTI)

??The Laser Triggered Switch Program at Sandia National Laboratories is an intensive development study to understand and optimize the laser triggered gas switch (LTGS) for… (more)

Clark, Waylon

2007-01-01T23:59:59.000Z

109

Zettawatt-Exawatt Lasers and Their Applications in Ultrastrong-Field Physics High Energy Front  

E-Print Network (OSTI)

Since its birth, the laser has been extraordinarily effective in the study and applications of laser-matter interaction at the atomic and molecular level and in the nonlinear optics of the bound electron. In its early life, the laser was associated with the physics of electron volts and of the chemical bond. Over the past fifteen years, however, we have seen a surge in our ability to produce high intensities, five to six orders of magnitude higher than was possible before. At these intensities, particles, electrons and protons, acquire kinetic energy in the mega-electron-volt range through interaction with intense laser fields. This opens a new age for the laser, the age of nonlinear relativistic optics coupling even with nuclear physics. We suggest a path to reach an extremely high-intensity level $10^{26-28} $W/cm$^2$ in the coming decade, much beyond the current and near future intensity regime $10^{23} $W/cm$^2$, taking advantage of the megajoule laser facilities. Such a laser at extreme high intensity co...

Tajima, T

2001-01-01T23:59:59.000Z

110

Dual wavelength laser damage testing for high energy lasers.  

Science Conference Proceedings (OSTI)

As high energy laser systems evolve towards higher energies, fundamental material properties such as the laser-induced damage threshold (LIDT) of the optics limit the overall system performance. The Z-Backlighter Laser Facility at Sandia National Laboratories uses a pair of such kiljoule-class Nd:Phosphate Glass lasers for x-ray radiography of high energy density physics events on the Z-Accelerator. These two systems, the Z-Beamlet system operating at 527nm/ 1ns and the Z-Petawatt system operating at 1054nm/ 0.5ps, can be combined for some experimental applications. In these scenarios, dichroic beam combining optics and subsequent dual wavelength high reflectors will see a high fluence from combined simultaneous laser exposure and may even see lingering effects when used for pump-probe configurations. Only recently have researchers begun to explore such concerns, looking at individual and simultaneous exposures of optics to 1064 and third harmonic 355nm light from Nd:YAG [1]. However, to our knowledge, measurements of simultaneous and delayed dual wavelength damage thresholds on such optics have not been performed for exposure to 1054nm and its second harmonic light, especially when the pulses are of disparate pulse duration. The Z-Backlighter Facility has an instrumented damage tester setup to examine the issues of laser-induced damage thresholds in a variety of such situations [2] . Using this damage tester, we have measured the LIDT of dual wavelength high reflectors at 1054nm/0.5ps and 532nm/7ns, separately and spatially combined, both co-temporal and delayed, with single and multiple exposures. We found that the LIDT of the sample at 1054nm/0.5ps can be significantly lowered, from 1.32J/cm{sup 2} damage fluence with 1054/0.5ps only to 1.05 J/cm{sup 2} with the simultaneous presence of 532nm/7ns laser light at a fluence of 8.1 J/cm{sup 2}. This reduction of LIDT of the sample at 1054nm/0.5ps continues as the fluence of 532nm/7ns laser light simultaneously present increases. The reduction of LIDT does not occur when the 2 pulses are temporally separated. This paper will also present dual wavelength LIDT results of commercial dichroic beam-combining optics simultaneously exposed with laser light at 1054nm/2.5ns and 532nm/7ns.

Atherton, Briggs W.; Rambo, Patrick K.; Schwarz, Jens; Kimmel, Mark W.

2010-05-01T23:59:59.000Z

111

Compact, high energy gas laser  

DOE Patents (OSTI)

An electrically pumped gas laser amplifier unit having a disc-like configuration in which light propagation is radially outward from the axis rather than along the axis. The input optical energy is distributed over a much smaller area than the output optical energy, i.e., the amplified beam, while still preserving the simplicity of parallel electrodes for pumping the laser medium. The system may thus be driven by a comparatively low optical energy input, while at the same time, owing to the large output area, large energies may be extracted while maintaining the energy per unit area below the threshold of gas breakdown.

Rockwood, Stephen D. (Los Alamos, NM); Stapleton, Robert E. (Los Alamos, NM); Stratton, Thomas F. (Los Alamos, NM)

1976-08-03T23:59:59.000Z

112

ELECTRON CLOUD EFFECTS IN HIGH INTENSITY PROTON ACCELERATORS.  

SciTech Connect

One of the primary concerns in the design and operation of high-intensity proton synchrotrons and accumulators is the electron cloud and associated beam loss and instabilities. Electron-cloud effects are observed at high-intensity proton machines like the Los Alamos National Laboratory's PSR and CERN's SPS, and investigated experimentally and theoretically. In the design of next-generation high-intensity proton accelerators like the Spallation Neutron Source ring, emphasis is made in minimizing electron production and in enhancing Landau damping. This paper reviews the present understanding of the electron-cloud effects and presents mitigation measures.

WEI,J.; MACEK,R.J.

2002-04-14T23:59:59.000Z

113

A New High Intensity Electron Beam for Wakefield Acceleration...  

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

HIGH INTENSITY ELECTRON BEAM FOR WAKEFIELD ACCELERATION STUDIES* M.E. Conde , W. Gai, C. Jing, R. Konecny, W. Liu, J.G. Power, H. Wang, Z. Yusof ANL, Argonne, IL 60439, USA...

114

High Energy Laser for Space Debris Removal  

SciTech Connect

The National Ignition Facility (NIF) and Photon Science Directorate at Lawrence Livermore National Laboratory (LLNL) has substantial relevant experience in the construction of high energy lasers, and more recently in the development of advanced high average power solid state lasers. We are currently developing new concepts for advanced solid state laser drivers for the Laser Inertial Fusion Energy (LIFE) application, and other high average power laser applications that could become central technologies for use in space debris removal. The debris population most readily addressed by our laser technology is that of 0.1-10 cm sized debris in low earth orbit (LEO). In this application, a ground based laser system would engage an orbiting target and slow it down by ablating material from its surface which leads to reentry into the atmosphere, as proposed by NASA's ORION Project. The ORION concept of operations (CONOPS) is also described in general terms by Phipps. Key aspects of this approach include the need for high irradiance on target, 10{sup 8} to 10{sup 9} W/cm{sup 2}, which favors short (i.e., picoseconds to nanoseconds) laser pulse durations and high energy per pulse ({approx} > 10 kJ). Due to the target's orbital velocity, the potential duration of engagement is only of order 100 seconds, so a high pulse repetition rate is also essential. The laser technology needed for this application did not exist when ORION was first proposed, but today, a unique combination of emerging technologies could create a path to enable deployment in the near future. Our concepts for the laser system architecture are an extension of what was developed for the National Ignition Facility (NIF), combined with high repetition rate laser technology developed for Inertial Fusion Energy (IFE), and heat capacity laser technology developed for military applications. The 'front-end' seed pulse generator would be fiber-optics based, and would generate a temporally, and spectrally tailored pulse designed for high transmission through the atmosphere, as well as efficient ablative coupling to the target. The main amplifier would use either diode-pumped or flashlamp-pumped solid state gain media, depending on budget constraints of the project. A continuously operating system would use the gas-cooled amplifier technology developed for Mercury, while a burst-mode option would use the heat capacity laser technology. The ground-based system that we propose is capable of rapid engagement of targets whose orbits cross over the site, with potential for kill on a single pass. Very little target mass is ablated per pulse so the potential to create additional hazardous orbiting debris is minimal. Our cost estimates range from $2500 to $5000 per J depending on choices for laser gain medium, amplifier pump source, and thermal management method. A flashlamp-pumped, Nd:glass heat-capacity laser operating in the burst mode would have costs at the lower end of this spectrum and would suffice to demonstrate the efficacy of this approach as a prototype system. A diode-pumped, gas-cooled laser would have higher costs but could be operated continuously, and might be desirable for more demanding mission needs. Maneuverability can be incorporated in the system design if the additional cost is deemed acceptable. The laser system would need to be coupled with a target pointing and tracking telescope with guide-star-like wavefront correction capability.

Barty, C; Caird, J; Erlandson, A; Beach, R; Rubenchik, A

2009-10-30T23:59:59.000Z

115

High Energy Laser for Space Debris Removal  

SciTech Connect

The National Ignition Facility (NIF) and Photon Science Directorate at Lawrence Livermore National Laboratory (LLNL) has substantial relevant experience in the construction of high energy lasers, and more recently in the development of advanced high average power solid state lasers. We are currently developing new concepts for advanced solid state laser drivers for the Laser Inertial Fusion Energy (LIFE) application, and other high average power laser applications that could become central technologies for use in space debris removal. The debris population most readily addressed by our laser technology is that of 0.1-10 cm sized debris in low earth orbit (LEO). In this application, a ground based laser system would engage an orbiting target and slow it down by ablating material from its surface which leads to reentry into the atmosphere, as proposed by NASA's ORION Project. The ORION concept of operations (CONOPS) is also described in general terms by Phipps. Key aspects of this approach include the need for high irradiance on target, 10{sup 8} to 10{sup 9} W/cm{sup 2}, which favors short (i.e., picoseconds to nanoseconds) laser pulse durations and high energy per pulse ({approx} > 10 kJ). Due to the target's orbital velocity, the potential duration of engagement is only of order 100 seconds, so a high pulse repetition rate is also essential. The laser technology needed for this application did not exist when ORION was first proposed, but today, a unique combination of emerging technologies could create a path to enable deployment in the near future. Our concepts for the laser system architecture are an extension of what was developed for the National Ignition Facility (NIF), combined with high repetition rate laser technology developed for Inertial Fusion Energy (IFE), and heat capacity laser technology developed for military applications. The 'front-end' seed pulse generator would be fiber-optics based, and would generate a temporally, and spectrally tailored pulse designed for high transmission through the atmosphere, as well as efficient ablative coupling to the target. The main amplifier would use either diode-pumped or flashlamp-pumped solid state gain media, depending on budget constraints of the project. A continuously operating system would use the gas-cooled amplifier technology developed for Mercury, while a burst-mode option would use the heat capacity laser technology. The ground-based system that we propose is capable of rapid engagement of targets whose orbits cross over the site, with potential for kill on a single pass. Very little target mass is ablated per pulse so the potential to create additional hazardous orbiting debris is minimal. Our cost estimates range from $2500 to $5000 per J depending on choices for laser gain medium, amplifier pump source, and thermal management method. A flashlamp-pumped, Nd:glass heat-capacity laser operating in the burst mode would have costs at the lower end of this spectrum and would suffice to demonstrate the efficacy of this approach as a prototype system. A diode-pumped, gas-cooled laser would have higher costs but could be operated continuously, and might be desirable for more demanding mission needs. Maneuverability can be incorporated in the system design if the additional cost is deemed acceptable. The laser system would need to be coupled with a target pointing and tracking telescope with guide-star-like wavefront correction capability.

Barty, C; Caird, J; Erlandson, A; Beach, R; Rubenchik, A

2009-10-30T23:59:59.000Z

116

Laser Drilling with Gated High Power Fiber Lasers  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2010. Symposium, Laser Applications in Materials Processing. Presentation Title, Laser Drilling ...

117

Investigation of non-stationary self-focusing of intense laser pulse in cold quantum plasma using ramp density profile  

SciTech Connect

The authors have investigated the non-stationary self-focusing of Gaussian laser pulse in cold quantum plasma. In case of high dense plasma, the nonlinearity in the dielectric constant is mainly due to relativistic high intense interactions and quantum effects. In this paper, we have introduced a ramp density profile for plasma and presented graphically the behavior of spot size oscillations of pulse at rear and front portions of the pulse. It is observed that the ramp density profile and quantum effects play a vital role in stronger and better focusing at the rear of the pulse than at the front in cold quantum plasmas.

Habibi, M. [Department of Physics, Shirvan Branch, Islamic Azad University, Shirvan (Iran, Islamic Republic of); Ghamari, F. [Department of Physics, Khorramabad Branch, Islamic Azad University, Khorramabad (Iran, Islamic Republic of)

2012-11-15T23:59:59.000Z

118

High power gas transport laser  

SciTech Connect

Continuous wave output power from a gas transport laser is substantially increased by disposing a plurality of parallel cylindrically tubular cathodes in the main stream transversely of the direction of gas flow and spaced above a coextensive segmented anode in the opposite wall of the channel. Ballast resistors are connected between the cathodes, respectively, and the power supply to optimize the uniform arcless distribution of current passing between each cathode and the anode. Continuous output power greater than 3 kW is achieved with this electrode configuration.

Fahlen, T.S.; Kirk, R.F.

1978-02-28T23:59:59.000Z

119

Enhancing the energy of terahertz radiation from plasma produced by intense femtosecond laser pulses  

SciTech Connect

Terahertz (THz) radiation from atomic clusters illuminated by intense femtosecond laser pulses is investigated. By studying the angular distribution, polarization properties and energy dependence of THz waves, we aim to obtain a proper understanding of the mechanism of THz generation. The properties of THz waves measured in this study differ from those predicted by previously proposed mechanisms. To interpret these properties qualitatively, we propose that the radiation is generated by time-varying quadrupoles, which are produced by the ponderomotive force of the laser pulse.

Jahangiri, Fazel [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan) [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan); Laser and Plasma Research Institute, Shahid Beheshti University, Tehran (Iran, Islamic Republic of); Hashida, Masaki; Tokita, Shigeki; Sakabe, Shuji [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan) [Advanced Research Center for Beam Science, ICR, Kyoto University, Kyoto (Japan); Department of Physics, GSS, Kyoto University, Kyoto (Japan); Nagashima, Takeshi; Hangyo, Masanori [Department of Physics, GSS, Kyoto University, Kyoto (Japan) [Department of Physics, GSS, Kyoto University, Kyoto (Japan); Institute of Laser Engineering, Osaka University, Osaka (Japan)

2013-05-13T23:59:59.000Z

120

High density laser-driven target  

DOE Patents (OSTI)

A high density target for implosion by laser energy composed of a central quantity of fuel surrounded by a high-Z pusher shell with a low-Z ablator-pusher shell spaced therefrom forming a region filled with low-density material.

Lindl, John D. (San Ramon, CA)

1981-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" 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

Electric dipole-forbidden nuclear transitions driven by super-intense laser fields  

E-Print Network (OSTI)

Electric dipole-forbidden transitions of nuclei interacting with super-intense laser fields are investigated considering stable isotopes with suitable low-lying first excited states. Different classes of transitions are identified, and all magnetic sublevels corresponding to the near-resonantly driven nuclear transition are included in the description of the nuclear quantum system. We find that large transition matrix elements and convenient resonance energies qualify nuclear M1 transitions as good candidates for the coherent driving of nuclei. We discuss the implications of resonant interaction of intense laser fields with nuclei beyond the dipole approximation for the controlled preparation of excited nuclear states and important aspects of possible experiments aimed at observing these effects.

Adriana Pálffy; Jörg Evers; Christoph H. Keitel

2007-10-31T23:59:59.000Z

122

Nonsequential double ionization below laser-intensity threshold: Anticorrelation of electrons without excitation of parent ion  

SciTech Connect

Two-electron correlated spectra of nonsequential double ionization below laser-intensity threshold are known to exhibit back-to-back scattering of the electrons, i.e., the anticorrelation of the electrons. Currently, the widely accepted interpretation of the anticorrelation is recollision-induced excitation of the ion plus subsequent field ionization of the second electron. We argue that another mechanism, namely, simultaneous electron emission, when the time of return of the rescattered electron is equal to the time of liberation of the bounded electron (i.e., the ion has no time for excitation), can also explain the anticorrelation of the electrons in the deep, below laser-intensity threshold regime. Our conclusion is based on the results of the numerical solution of the time-dependent Schroedinger equation for a model system of two one-dimensional electrons, as well as on an adiabatic analytic model that allows for a closed-form solution.

Bondar, D. I. [University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); National Research Council of Canada, Ottawa, Ontario K1A 0R6 (Canada); Yudin, G. L. [National Research Council of Canada, Ottawa, Ontario K1A 0R6 (Canada); Universite de Sherbrooke, Sherbrooke, Quebec J1K 2R1 (Canada); Liu, W.-K. [University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Ivanov, M. Yu. [Imperial College, London SW7 2BW (United Kingdom); Bandrauk, A. D. [Universite de Sherbrooke, Sherbrooke, Quebec J1K 2R1 (Canada)

2011-01-15T23:59:59.000Z

123

Creating intense polarized electron beam via laser stripping and spin-orbit interaction  

DOE Green Energy (OSTI)

The recent advance in laser field make it possible to excite and strip electrons with definite spin from hydrogen atoms. The sources of hydrogen atoms with orders of magnitude higher currents (than that of the conventional polarized electron cathods) can be obtained from H{sup -} sources with good monochromatization. With one electron of H{sup -} stripped by a laser, the remained electron is excited to upper state (2P{sup 3/2} and 2P{sup 1/2}) by a circular polarization laser light from FEL. Then, it is excited to a high quantum number (n=7) with mostly one spin direction due to energy level split of the states with a definite direction of spin and angular momentum in an applied magnetic field and then it is stripped by a strong electric field of an RF cavity. This paper presents combination of lasers and fields to get high polarization and high current electron source.

Danilov, V.; Ptitsyn, V.; Gorlov, T.

2010-12-01T23:59:59.000Z

124

On the high intensity aspects of AGS Booster proton operation  

SciTech Connect

Observations of high intensity effects on the proton performance of the AGS Booster are presented, including present operational limits and correction methods. The transverse emittances, optimum tune working points, damping of coherent transverse oscillations and correction of stopband resonances through third-order are discussed in addition to the observed tune spread due to space charge forces. The initial longitudinal phase space distribution, capture and acceleration parameters and measurements are also given. Operational tools and strategies relevant to the high intensity setup are mentioned.

Reece, R.K.; Ahrens, L.A.; Bleser, E.J.; Brennan, J.M.; Gardner, C.; Glenn, J.W.; Roser, T.; Shoji, Y.; van Asselt, W.; Weng, W.T.

1993-06-01T23:59:59.000Z

125

On the high intensity aspects of AGS Booster proton operation  

SciTech Connect

Observations of high intensity effects on the proton performance of the AGS Booster are presented, including present operational limits and correction methods. The transverse emittances, optimum tune working points, damping of coherent transverse oscillations and correction of stopband resonances through third-order are discussed in addition to the observed tune spread due to space charge forces. The initial longitudinal phase space distribution, capture and acceleration parameters and measurements are also given. Operational tools and strategies relevant to the high intensity setup are mentioned.

Reece, R.K.; Ahrens, L.A.; Bleser, E.J.; Brennan, J.M.; Gardner, C.; Glenn, J.W.; Roser, T.; Shoji, Y.; van Asselt, W.; Weng, W.T.

1993-01-01T23:59:59.000Z

126

High intensity performance and upgrades at the Brookhaven AGS  

SciTech Connect

The high intensity proton beam of the AGS is used both for the slow-extracted-beam (SEB) area with many target station to produce secondary beams and the fast-extracted-beam (FEB) line used for the production of muons for the g-2 experiment and for high intensity target testing for the spallation neutron sources and muon production targets for the muon collider. The same FEB line will also be used for the transfer of beam to RHIC. The proton beam intensity in the AGS has increased steadily over the 35 year existence of the AGS, but the most dramatic increase occurred over the last couple of years with the addition of the new AGS Booster. All modifications associated with this are discussed.

Roser, T.

1998-12-01T23:59:59.000Z

127

High-Energy Petawatt Capability for the Omega Laser  

Science Conference Proceedings (OSTI)

The 60-beam Omega laser system at the University of Rochester's Laboratory for Laser Energetics (LLE) has been a workhorse on the frontier of laser fusion and high-energy-density physics for more than a decade. LLE scientists are currently extending the performance of this unique, direct-drive laser system by adding high-energy petawatt capabilities.

Waxer, L.J.; Maywar, D.N.; Kelly, J.H.; Kessler, T.J.; Kruschwitz, B.E.; Loucks, S.J.; McCrory, R.L.; Meyerhofer, D.D.; Morse, S.F.B.; Stoeckl, C.; Zuegel, J.D.

2005-07-25T23:59:59.000Z

128

System and method that suppresses intensity fluctuations for free space high-speed optical communication  

DOE Patents (OSTI)

A high-speed (Gbps), free space optical communication system is based on spectral encoding of radiation from a wide band light source, such as a laser. By using partially coherent laser beams in combination with a relatively slow photosensor, scintillations can be suppressed by orders of magnitude for distances of more than 10 km. To suppress the intensity fluctuations due to atmospheric turbulence, a source with partial transverse coherence in combination with slow response time photodetector is used. Information is encoded in the spectral domain of a wideband optical source by modulation of spectral amplitudes. A non-coherent light source with wide spectrum (an LED, for example) may be used for high-speed communication over short (less than about a mile) distances.

Berman, Gennady P. (Los Alamos, NM); Bishop, Alan R. (Los Alamos, NM); Nguyen, Dinh C. (Los Alamos, NM); Chernobrod, Boris M. (Santa Fe, NM); Gorshkov, Vacheslav N. (Kiev, UA)

2009-10-13T23:59:59.000Z

129

Drift tube suspension for high intensity linear accelerators  

DOE Patents (OSTI)

The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

Liska, D.J.; Schamaun, R.G.; Clark, D.C.; Potter, R.C.; Frank, J.A.

1980-03-11T23:59:59.000Z

130

Critical design issues of high intensity proton linacs  

SciTech Connect

Medium-energy proton linear accelerators are being studied as drivers for spallation applications requiring large amounts of beam powder. Important design factors for such high-intensity linacs are reviewed, and issues and concerns specific to this unprecedented power regime are discussed.

Lawrence, G.P.

1994-08-01T23:59:59.000Z

131

Drift tube suspension for high intensity linear accelerators  

SciTech Connect

The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

Liska, Donald J. (Los Alamos, NM); Schamaun, Roger G. (Los Alamos, NM); Clark, Donald C. (Los Alamos, NM); Potter, R. Christopher (Los Alamos, NM); Frank, Joseph A. (Los Alamos, NM)

1982-01-01T23:59:59.000Z

132

Some Intensive and Extensive Quantities in High-Energy Collisions  

E-Print Network (OSTI)

We review the evolution of some statistical and thermodynamical quantities measured in difference sizes of high-energy collisions at different energies. We differentiate between intensive and extensive quantities and discuss the importance of their distinguishability in characterizing possible critical phenomena of nuclear collisions at various energies with different initial conditions.

Tawfik, A

2013-01-01T23:59:59.000Z

133

Improved Spatial Filter for high power Lasers  

DOE Patents (OSTI)

A new pinhole architecture incorporates features intended to reduce the rate of plasma generation in a spatial filter for high-energy laser pulse beams. An elongated pinhole aperture is provided in an apertured body for rejecting off-axis rays of the laser pulse beam. The internal surface of the elongated aperture has a diameter which progressively tapers from a larger entrance cross-sectional area at an inlet to a smaller output cross-sectional area at an outlet. The tapered internal surface causes off-axis rays to be refracted in a low density plasma layer that forms on the internal surface or specularly reflected at grazing incidence from the internal surface. Off-axis rays of the high-energy pulse beam are rejected by this design. The external surface of the apertured body adjacent to the larger entrance cross-sectional area at the inlet to the elongated aperture is angled obliquely with respect to the to direction of the path of the high-energy laser pulse beam to backscatter off-axis rays away from the high-energy pulse beam. The aperture is formed as a truncated cone or alternatively with a tapered square cross-section. The internal surface of the aperture is coated with an ablative material, preferably high-density material which can be deposited with an exploding wire.

Estabrook, Kent G.; Celliers, Peter M.; Murray, James E.; DaSilva, Luiz; MacGowan, Brian J.; Rubenchik, Alexander M.; Manes, Kenneth R.; Drake, Robert P.; Afeyan, Bedros

1998-06-01T23:59:59.000Z

134

Double-slit vacuum polarisation effects in ultra-intense laser fields  

E-Print Network (OSTI)

The influence of the strong laser-driven vacuum on a propagating electromagnetic probe wave has been studied in detail. We investigate two scenarios comprising a focused probe laser beam passing through a region of vacuum polarised by an ultra-intense laser field. By splitting this strong field into two, separated, monochromatic Gaussian pulses counter-propagating in a plane perpendicular to the probe field axis, we demonstrate a leading order light-by-light diffraction effect that generates an interference pattern reminiscent of the classic double-slit experiment. We calculate the total number of probe photons diffracted as well as the number diffracted into regions where the vacuum polarisation signal is higher than the probe background. In addition, we calculate the induced ellipticity and polarisation rotation in the probe beam and show how, in the realistic situation in which the centres of the two strong fields are not exactly aligned, certain ranges of beam separation and observation distance may actually lead to an increase over the idealised case of a single strong laser beam.

B. King; A. Di Piazza; C. H. Keitel

2013-01-29T23:59:59.000Z

135

Ionisation of hydrogen molecule in intense ultrashort laser pulses: parallel versus perpendicular orientation  

E-Print Network (OSTI)

A theoretical comparison of the electronic excitation and ionisation behaviour of molecular hydrogen oriented either parallel or perpendicular to a linear polarised laser pulse is performed. The investigation is based on a non-perturbative treatment that solves the full time-dependent Schr\\"odinger equation of both correlated electrons within the fixed-nuclei approximation and the dipole. Results are shown for two different laser pulse lengths and intensities as well as for a large variety of photon frequencies starting in the 1- and reaching into the 6-photon regime. In order to investigate the influence of the intrinsic diatomic two-center problem even further, two values of the internuclear separation and a newly developed atomic model are considered.

Yulian V. Vanne; Alejandro Saenz

2008-04-03T23:59:59.000Z

136

Electron Generation and Transport in Intense Relativistic Laser-Plasma Interactions Relevant to Fast Ignition ICF  

SciTech Connect

The reentrant cone approach to Fast Ignition, an advanced Inertial Confinement Fusion scheme, remains one of the most attractive because of the potential to efficiently collect and guide the laser light into the cone tip and direct energetic electrons into the high density core of the fuel. However, in the presence of a preformed plasma, the laser energy is largely absorbed before it can reach the cone tip. Full scale fast ignition laser systems are envisioned to have prepulses ranging between 100 mJ to 1 J. A few of the imperative issues facing fast ignition, then, are the conversion efficiency with which the laser light is converted to hot electrons, the subsequent transport characteristics of those electrons, and requirements for maximum allowable prepulse this may put on the laser system. This dissertation examines the laser-to-fast electron conversion efficiency scaling with prepulse for cone-guided fast ignition. Work in developing an extreme ultraviolet imager diagnostic for the temperature measurements of electron-heated targets, as well as the validation of the use of a thin wire for simultaneous determination of electron number density and electron temperature will be discussed.

Ma, T

2010-04-21T23:59:59.000Z

137

BEAM HALO FORMATION IN HIGH-INTENSITY BEAMS.  

SciTech Connect

Studies of beam halo became unavoidable feature of high-intensity machines where uncontrolled beam loss should be kept to extremely small level. For a well controlled stable beam such a loss is typically associated with the low density halo surrounding beam core. In order to minimize uncontrolled beam loss or improve performance of an accelerator, it is very important to understand what are the sources of halo formation in a specific machine of interest. The dominant mechanisms are, in fact, different in linear accelerators, circular machines or Energy Recovering Linacs (ERL). In this paper, we summarize basic mechanisms of halo formation in high-intensity beams and discuss their application to various types of accelerators of interest, such as linacs, rings and ERL.

FEDOTOV, A.V.

2005-03-18T23:59:59.000Z

138

High gain x-ray lasers pumped by transient collisional excitation  

Science Conference Proceedings (OSTI)

We present recent results of x-ray laser amplification of spontaneous emission in Ne-like and Ni-like transient collisional excitation schemes. The plasma formation, ionization and collisional excitation can be optimized using two laser pulses of 1 ns and 1 ps duration at table-top energies of 5 J in each beam. High gain of 35 cm{sup -1} has been measured on the 147 {Angstrom} 4d{r_arrow}4p J=0{r_arrow}1 transition of Ni-like Pd and is a direct consequence of the nonstationary population inversion produced by the high intensity picosecond pulse. We report the dependence of the x-ray laser line intensity on the laser plasma conditions and compare the experimental measurements with hydrodynamic and atomic kinetics simulations for Ne-like and Ni-like lasing.

Dunn, J., LLNL

1998-06-16T23:59:59.000Z

139

Laser for high frequency modulated interferometry  

DOE Patents (OSTI)

A Stark-tuned laser operating in the 119 micron line of CH[sub 3]OH has an output power of several tens of milliwatts at 30 Watts of pump power while exhibiting a doublet splitting of about ten MHz with the application of a Stark field on the order of 500 volts/cm. This output power allows for use of the laser in a multi-channel interferometer, while its high operating frequency permits the interferometer to measure rapid electron density changes in a pellet injected or otherwise fueled plasma such as encountered in magnetic fusion devices. The laser includes a long far-infrared (FIR) pyrex resonator tube disposed within a cylindrical water jacket and incorporating charged electrodes for applying the Stark field to a gas confined therein. With the electrodes located within the resonator tube, the resonator tube walls are cooled by a flowing coolant without electrical breakdown in the coolant liquid during application of the Stark field. Wall cooling allows for substantially increased FIR output powers. Provision is made for introducing a buffer gas into the resonator tube for increasing laser output power and its operating bandwidth. 10 figures.

Mansfield, D.K.; Vocaturo, M.; Guttadora, L.J.

1991-07-23T23:59:59.000Z

140

Laser for high frequency modulated interferometry  

DOE Patents (OSTI)

A Stark-tuned laser operating in the 119 micron line of CH.sub.3 OH has an output power of several tens of milliwatts at 30 Watts of pump power while exhibiting a doublet splitting of about ten MHz with the application of a Stark field on the order of 500 volts/cm. This output power allows for use of the laser in a multi-channel interferometer, while its high operating frequency permits the interferometer to measure rapid electron density changes in a pellet injected or otherwise fueled plasma such as encountered in magnetic fusion devices. The laser includes a long far-infrared (FIR) pyrex resonator tube disposed within a cylindrical water jacket and incorporating charged electrodes for applying the Stark field to a gas confined therein. With the electrodes located within the resonator tube, the resonator tube walls are cooled by a flowing coolant without electrical breakdown in the coolant liquid during application of the Stark field. Wall cooling allows for substantially increased FIR output powers. Provision is made for introducing a buffer gas into the resonator tube for increasing laser output power and its operating bandwidth.

Mansfield, Dennis K. (E. Windsor, NJ); Vocaturo, Michael (Columbus, NJ); Guttadora, Lawrence J. (Iselin, NJ)

1991-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" 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

Laser for high frequency modulated interferometry  

DOE Patents (OSTI)

A Stark-tuned laser operating in the 119 micron line of CH{sub 3}OH has an output power of several tens of milliwatts at 30 Watts of pump power while exhibiting a doublet splitting of about ten MHz with the application of a Stark field on the order of 500 volts/cm. This output power allows for use of the laser in a multi-channel interferometer, while its high operating frequency permits the interferometer to measure rapid electron density changes in a pellet injected or otherwise fueled plasma such as encountered in magnetic fusion device. The laser includes a long far-infrared (FIR) Pyrex resonator tube disposed within a cylindrical water jacket and incorporating charged electrodes for applying the Stark field to a gas confined therein. With the electrodes located within the resonator tube, the resonator tube walls are cooled by a flowing coolant without electrical breakdown in the coolant liquid during application of the Stark field. Wall cooling allows for substantially increased FIR output powers. Provision is made for introducing a buffer gas into the resonator tube for increasing laser output power and its operating bandwidth.

Mansfield, D.K.; Vocatura, M.; Guttadora, L.J.

1989-12-05T23:59:59.000Z

142

Laboratory high-energy astrophysics on lasers  

SciTech Connect

The tremendous range of temperatures and densities spanned by astrophysical plasmas has significant overlap with conditions attainable using high-power laser facilities. These facilities provide an opportunity to create, control, and characterize plasmas in the laboratory that mirror conditions in some of the most important cosmological systems. Moreover, laboratory experiments can enhance astrophysical understanding by focusing on and isolating important physical processes, without necessarily reproducing the exact conditions of the integral system. Basic study of radiative properties, transport phenomena, thermodynamic response and hydrodynamic evolution in plasmas under properly scaled conditions leads both directly and indirectly to improved models of complex astrophysical systems. In this paper, we will discuss opportunities for current and planned highpower lasers to contribute to the study of high-energy astrophysics.

Goldstein, W.H.; Liedahl, D.A.; Walling, R.S.; Foord, M.E.; Osterheld, A.L.; Wilson, B.G.

1994-12-01T23:59:59.000Z

143

Scaling of Pressure with Intensity in Laser-Driven Shocks and Effects of Hot X-ray Preheat  

SciTech Connect

To drive shocks into solids with a laser we either illuminate the material directly, or to get higher pressures, illuminate a plastic ablator that overlays the material of interest. In both cases the illumination intensity is low, <<10{sup 13} W/cm{sup 2}, compared to that for traditional laser fusion targets. In this regime, the laser beam creates and interacts with a collisional, rather than a collisionless, plasma. We present scaling relationships for shock pressure with intensity derived from simulations for this low-intensity collisional plasma regime. In addition, sometimes the plastic-ablator targets have a thin flashcoating of Al on the plastic surface as a shine-through barrier; this Al layer can be a source of hot x-ray preheat. We discuss how the preheat affects the shock pressure, with application to simulating VISAR measurements from experiments conducted on various lasers on shock compression of Fe.

Colvin, J D; Kalantar, D H

2005-08-29T23:59:59.000Z

144

High-Power Solid-State Lasers from a Laser Glass Perspective  

Science Conference Proceedings (OSTI)

Advances in laser glass compositions and manufacturing have enabled a new class of high-energy/high-power (HEHP), petawatt (PW) and high-average-power (HAP) laser systems that are being used for fusion energy ignition demonstration, fundamental physics research and materials processing, respectively. The requirements for these three laser systems are different necessitating different glasses or groups of glasses. The manufacturing technology is now mature for melting, annealing, fabricating and finishing of laser glasses for all three applications. The laser glass properties of major importance for HEHP, PW and HAP applications are briefly reviewed and the compositions and properties of the most widely used commercial laser glasses summarized. Proposed advances in these three laser systems will require new glasses and new melting methods which are briefly discussed. The challenges presented by these laser systems will likely dominate the field of laser glass development over the next several decades.

Campbell, J H; Hayden, J S; Marker, A J

2010-12-17T23:59:59.000Z

145

Laser Guiding at Relativistic Intensities and Wakefield Particle Acceleration in Plasma Channels  

E-Print Network (OSTI)

pulsed, THz radiation from laser accelerated relativisticGuiding of Relativistic Laser Pulses by Plasma Channels,"Wake Fields by Colliding Laser Pulses,"Phys. Rev. Lett.

2005-01-01T23:59:59.000Z

146

High-power semiconductor separate-confinement double heterostructure lasers  

Science Conference Proceedings (OSTI)

The review is devoted to high-power semiconductor lasers. Historical reference is presented, physical and technological foundations are considered, and the concept of high-power semiconductor lasers is formulated. Fundamental and technological reasons limiting the optical power of a semiconductor laser are determined. The results of investigations of cw and pulsed high-power semiconductor lasers are presented. Main attention is paid to inspection of the results of experimental studies of single high-power semiconductor lasers. The review is mainly based on the data obtained in the laboratory of semiconductor luminescence and injection emitters at the A.F. Ioffe Physicotechnical Institute. (review)

Tarasov, I S [A.F. Ioffe Physical-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation)

2010-10-15T23:59:59.000Z

147

HIGH INTENSITY PERFORMANCE AND UPGRADES AT THE BROOKHAVEN AGS  

SciTech Connect

Fig. 1 shows the present layout of the AGS-RHIC accelerator complex. The high intensity proton beam of the AGS is used both for the slow-extracted-beam (SEB) area with many target station to produce secondary beams and the fast-extracted-beam (FEB) line used for the production of muons for the g-2 experiment and for high intensity target testing for the spallation neutron sources and muon production targets for the muon collider. The same FEB line will also be used for the transfer of beam to RHIC. The proton beam intensity in the AGS has increased steadily over the 35 year existence of the AGS, but the most dramatic increase occurred over the last couple of years with the addition of the new AGS Booster[1]. In Fig. 2 the history of the AGS intensity improvements is shown and the major upgrades are indicated. The AGS Booster has one quarter the circumference of the AGS and therefore allows four Booster beam pulses to be stacked in the AGS at an injection energy of 1.5--1.9 GeV. At this increased energy, space charge forces are much reduced and this in turn allows for the dramatic increase in the AGS beam intensity. The 200 MeV LINAC is being used both for the injection into the Booster as well as an isotope production facility. A recent upgrade of the LINAC rf system made it possible to operated at an average H{sup {minus}} current of 150 {micro}A and a maximum of 12 x 10{sup 13} H{sup {minus}} per 500 {micro}s LINAC pulse for the isotope production target. Typical beam currents during the 500 {micro}s pulse are about 80 mA at the source, 60 mA after the 750 keV RFQ, 38 mA after the first LINAC tank (10 MeV), and 37 mA at end of the LINAC at 200 MeV. The normalized beam emittance is about 2 {pi} mm mrad for 95% of the beam and the beam energy spread is about {+-}1.2 MeV. A magnetic fast chopper installed at 750 keV allows the shaping of the beam injected into the Booster to avoid excessive beam loss.

ROSER,T.

1998-05-04T23:59:59.000Z

148

ELECTRON COUD DYNAMICS IN HIGH-INTENSITY RINGS.  

SciTech Connect

Electron cloud due to beam-induced multipacting is one of the main concerns for the high intensity. Electrons generated and accumulated inside the beam pipe form an ''electron cloud'' that interacts with the circulating charged particle beam. With sizeable amount of electrons, this interaction can cause beam instability, beam loss and emittance growth. At the same time, the vacuum pressure will rise due to electron desorption. This talk intends to provide an overview of the mechanism and dynamics of the typical electron multipacting in various magnetic fields and mitigation measures with different beams.

WANG, L.; WEI, J.

2005-05-16T23:59:59.000Z

149

CW high intensity non-scaling FFAG proton drivers  

SciTech Connect

Accelerators are playing increasingly important roles in basic science, technology, and medicine including nuclear power, industrial irradiation, material science, and neutrino production. Proton and light-ion accelerators in particular have many research, energy and medical applications, providing one of the most effective treatments for many types of cancer. Ultra high-intensity and high-energy (GeV) proton drivers are a critical technology for accelerator-driven sub-critical reactors (ADS) and many HEP programs (Muon Collider). These high-intensity GeV-range proton drivers are particularly challenging, encountering duty cycle and space-charge limits in the synchrotron and machine size concerns in the weaker-focusing cyclotrons; a 10-20 MW proton driver is not presently considered technically achievable with conventional re-circulating accelerators. One, as-yet, unexplored re-circulating accelerator, the Fixed-field Alternating Gradient, or FFAG, is an attractive alternative to the cyclotron. Its strong focusing optics are expected to mitigate space charge effects, and a recent innovation in design has coupled stable tunes with isochronous orbits, making the FFAG capable of fixed-frequency, CW acceleration, as in the classical cyclotron. This paper reports on these new advances in FFAG accelerator technology and references advanced modeling tools for fixed-field accelerators developed for and unique to the code COSY INFINITY.

Johnstone, C.; /Fermilab; Berz, M.; Makino, K.; /Michigan State U.; Snopok, P.; /IIT, Chicago

2011-04-01T23:59:59.000Z

150

High-charge energetic electron bunch generated by intersecting laser pulses  

SciTech Connect

The interaction of two energetic electron bunches generated in the wakefields of two intense intersecting laser pulses in rarefied plasmas is investigated using particle-in-cell simulations. It is found that, with suitable intersection angle between the two laser pulses, the initially independent wakefield accelerated electron bunches can merged into a single one with high charge, energy, and narrow energy spread. The dynamics of the laser-pulse intersection and wake-bubble merging process is also investigated, and the crucial roles of the intersection angle are pointed out and analyzed.

Yang Lei; Deng Zhigang [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Department of Physics, Zhejiang University, Hangzhou 310027 (China); Zhou, C. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Yu, M. Y. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Wang, Xingang [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Department of Physics, Zhejiang University, Hangzhou 310027 (China); College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062 (China)

2013-03-15T23:59:59.000Z

151

High-Energy Petawatt Project at the University of Rochester's Laboratory for Laser Energetics  

Science Conference Proceedings (OSTI)

A high-energy petawatt laser, OMEGA EP, is currently under construction at the University of Rochester's Laboratory for Laser Energetics. Integrated into the existing OMEGA laser, it will support three major areas of research: (a) backlighting of high-energy-density plasmas, (b) integrated fast ignition experiments, and (c) high-intensity physics. The laser will provide two beams combined collinearly and coaxially with short pulses (~1 to 100 ps) and high energy (2.6 kJ at 10 ps). Cone-in-shell fuel-assembly experiments and simulations of short-pulse heated cryogenic targets are being performed in preparation for cryogenic integrated fast ignitor experiments on OMEGA EP.

Stoeckl, C.; Delettrez, J.A.; Kelly, J.H.; Kessler, T.J.; Kruschwitz, B.E.; Loucks, S.J.; McCrory, R.L.; Meyerhofer, D.D.; Maywar, D.N.; Morse, S.F.B.; Myatt, J.; Rigatti, A.L.; Waxer, L.J.; Zuegel, J.D.; Stephens, R.B.

2006-04-12T23:59:59.000Z

152

Evidence for ultra-fast heating in intense-laser irradiated reduced-mass targets  

Science Conference Proceedings (OSTI)

We report on an experiment irradiating individual argon droplets of 20 {mu}m diameter with laser pulses of several Joule energy at intensities of 10{sup 19} W/cm{sup 2}. K-shell emission spectroscopy was employed to determine the hot electron energy fraction and the time-integrated charge-state distribution. Spectral fitting indicates that bulk temperatures up to 160 eV are reached. Modelling of the hot-electron relaxation and generation of K-shell emission with collisional hot-electron stopping only is incompatible with the experimental results, and the data suggest an additional ultra-fast (sub-ps) heating contribution. For example, including resistive heating in the modelling yields a much better agreement with the observed final bulk temperature and qualitatively reproduces the observed charge state distribution.

Neumayer, P.; Gumberidze, A.; Hochhaus, D. C. [ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Frankfurt Institute for Advanced Studies FIAS, 60438 Frankfurt am Main (Germany); Aurand, B.; Stoehlker, T. [Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Costa Fraga, R. A.; Kalinin, A. [Institut fuer Kernphysik, J. W. Goethe University Frankfurt, 60438 Frankfurt am Main (Germany); Ecker, B. [Johannes Gutenberg University Mainz, 55099 Mainz (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Grisenti, R. E. [Institut fuer Kernphysik, J. W. Goethe University Frankfurt, 60438 Frankfurt am Main (Germany); Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Kaluza, M. C. [Helmholtz Institute Jena, 07743 Jena (Germany); IOQ Institute of Optics and Quantum Electronics, University of Jena (Germany); Kuehl, T. [Johannes Gutenberg University Mainz, 55099 Mainz (Germany); Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany); Helmholtz Institute Jena, 07743 Jena (Germany); Polz, J. [IOQ Institute of Optics and Quantum Electronics, University of Jena (Germany); Reuschl, R. [ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum fuer Schwerionenforschung, 64291 Darmstadt (Germany); Winters, D.; Winters, N.; Yin, Z. [Helmholtzzentrum fuer Schwerionenforschung GSI, 64291 Darmstadt (Germany)

2012-12-15T23:59:59.000Z

153

Comparison of techniques for solving the Laser Intensity Modulation Method (LIMM) equation  

Science Conference Proceedings (OSTI)

The Laser Intensity Modulation Method (LIMM) is a technique for the determination of polarization and/or space charge profiles in the thickness direction of ceramic and polymeric samples. The experimental data are analyzed by means of a Fredholm integral equation of the first kind. This equation admits to multiple and very different solutions. A number of techniques have been developed in order to obtain the most physically reasonable profile. Several techniques based on the regularization method have been proposed. A recent version, polynomial regularization, was developed by Lang. A completely different approach is the Monte Carlo method of Tuncer and Lang. Several sets of both simulated and experimental data are analyzed by the two methods in this paper. Conclusions concerning speed and accuracy are presented.

Lang, S B [Ben Gurion University of the Negev; Tuncer, Enis [ORNL

2008-01-01T23:59:59.000Z

154

Summary of sessions B and F: High intensity linacs and frontend & proton drivers  

SciTech Connect

This paper summarizes the sessions B&F of the 33rd ICFA Advanced Beam Dynamics Workshop on High Intensity & High Brightness Hadron Beams held in Bensheim, Germany. It covers high intensity linacs, front ends and proton driver topics.

Ferdinand, R.; /Saclay; Chou, W.; /Fermilab; Galambos, J.; /Oak Ridge

2005-01-01T23:59:59.000Z

155

Method and apparatus for tuning high power lasers  

DOE Patents (OSTI)

This invention relates to high power gas lasers that are adapted to be tuned to a desired lasing wavelength through the use of a gas cell to lower the gain at a natural lasing wavelength and "seeding" the laser with a beam from a low power laser which is lasing at the desired wavelength. This tuning is accomplished with no loss of power and produces a pulse with an altered pulse shape. It is potentially applicable to all gas lasers.

Hutchinson, Donald P. (Knoxville, TN); Vandersluis, Kenneth L. (Oak Ridge, TN)

1977-04-19T23:59:59.000Z

156

Resonant Auger Decay of Molecules in Intense X-Ray Laser Fields: Light-Induced Strong Nonadiabatic Effects  

Science Conference Proceedings (OSTI)

The resonant Auger process is studied in intense x-ray laser fields. It is shown that the dressing of the initial and decaying states by the field leads to coupled complex potential surfaces which, even for diatomic molecules, possess intersections at which the nonadiabatic couplings are singular. HCl is studied as an explicit showcase example. The exact results differ qualitatively from those without rotations. A wealth of nonadiabatic phenomena is expected in decay processes in intense x-ray fields.

Cederbaum, Lorenz S.; Chiang, Ying-Chih; Demekhin, Philipp V. [Theoretische Chemie, Universitaet Heidelberg, Im Neuenheimer Feld 229, 69120 Heidelberg (Germany); Moiseyev, Nimrod [Schulich Faculty of Chemistry and Minerva Center, Technion--Israel Institute of Technology, Haifa 32000 (Israel)

2011-03-25T23:59:59.000Z

157

HIGH INTENSITY LIGHT SOURCES (Part II of Thesis)  

SciTech Connect

A stable carbon arc operated in controlled atmosphere is described. The arc was designed to serve as a light source during lifetime studies of the B/sup 2/ SIGMA state of the CN molecule. The CN radiation from the plasma of the arc was investigated and found to have a brightness temperature of 5500 icient laborato K at lambda 3883 A. This is considerably higher than an estimate of the value required for lifetime measurements. The stability of the carbon arc under various conditions is discussed. For successful lifetime measurements, the light source employed must have a high brightness temperature (intensity). A method for the determination of the brightness temperature of a light source at a specific wave length is described. The method was used for determining the brightness temperatures of some available light sources. Sodium, thallium, and mercury discharge lamps, a medium-pressure mercury arc lamp, and the carbon arc were studied. (auth)

Worden, E.F. Jr.

1958-10-01T23:59:59.000Z

158

Super-high density laser fusion CTR  

SciTech Connect

From sixth European conference on controlled fusion and plasma physics; Moscow, USSR (30 Jul 1973). A basic discussion of laser-induced fusion is presented. Implosion development and applications are described. Implosion and thermonuclear physics are discussed in some detail along with laser technology, laser fusion reactors, and fusion energy conversion. (MOW)

Thiessen, A.; Zimmerman, G.; Weaver, T.; Emmett, J.; Nuckolls, J.; Wood, L.

1973-09-01T23:59:59.000Z

159

Future scientific applications for high-energy lasers  

Science Conference Proceedings (OSTI)

This report discusses future applications for high-energy lasers in the areas of astrophysics and space physics; hydrodynamics; material properties; plasma physics; radiation sources; and radiative properties.

Lee, R.W. [comp.

1994-08-01T23:59:59.000Z

160

High Temperature Fatigue Behavior of Laser Shock Peened ...  

Science Conference Proceedings (OSTI)

Presentation Title, High Temperature Fatigue Behavior of Laser Shock Peened IN718Plus Superalloy. Author(s), Vibhor Chaswal, S R Mannava, Dong Qian, ...

Note: This page contains sample records for the topic "high intensity laser" 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

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

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

Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Researchers at Berkeley Lab have been exploring the ways coherent synchrotron radiation (CSR) is generated in...

162

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

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

Power Coherent Terahertz Radiation Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Wednesday, 25 April 2007 00:00 Researchers at Berkeley Lab have been exploring...

163

Dissociation dynamics of diatomic molecules in intense laser fields: a scheme for the selection of relevant adiabatic potential curves  

E-Print Network (OSTI)

Dissociation dynamics of diatomic molecules in intense laser fields: a scheme for the selection wave packet emerges mainly on the repulsive |2pu > state, while a bound oscillat- ing part of the wave electronic states serve as a first criterion for se- lecting essential potential curves. This selection pro

Thumm, Uwe

164

High energy mode locked fiber oscillators for high contrast, high energy petawatt laser seed sources  

Science Conference Proceedings (OSTI)

In a high-energy petawatt laser beam line the ASE pulse contrast is directly related to the total laser gain. Thus a more energetic input pulse will result in increased pulse contrast at the target. We have developed a mode-locked fiber laser with high quality pulses and energies exceeding 25nJ. We believe this 25nJ result is scalable to higher energies. This oscillator has no intra-cavity dispersion compensation, which yields an extremely simple, and elegant laser configuration. We will discuss the design of this laser, our most recent results and characterization of all the key parameters relevant to it use as a seed laser. Our oscillator is a ring cavity mode-locked fiber laser [1]. These lasers operate in a self-similar pulse propagation regime characterized by a spectrum that is almost square. This mode was found theoretically [2] to occur only in the positive dispersion regime. Further increasing positive dispersion should lead to increasing pulse energy [2]. We established that the positive dispersion required for high-energy operation was approximately that of 2m of fiber. To this end, we constructed a laser cavity similar to [1], but with no gratings and only 2m of fiber, which we cladding pumped in order to ensure sufficient pump power was available to achieve mode-locked operation. A schematic of the laser is shown in figure 1 below. This laser produced low noise 25nJ pulses with a broad self similar spectrum (figure 2) and pulses that could be de-chirped to <100fs (figure 3). Pulse contrast is important in peta-watt laser systems. A major contributor to pulse contrast is amplified spontaneous emission (ASE), which is proportional to the gain in the laser chain. As the oscillator strength is increased, the required gain to reach 1PW pulses is decreased, reducing ASE and improving pulse contrast. We believe these lasers can be scaled in a stable fashion to pulse energies as high as 100nJ and have in fact seen 60nJ briefly in our lab, which is work still in progress. At this level, even if the pulses are not perfect, post-oscillator pulse cleaning can be used to create a clean high energy pulse for injection into a peta-watt laser beam line.

Dawson, J W; Messerly, M J; An, J; Kim, D; Barty, C J

2006-06-15T23:59:59.000Z

165

Beam experiments towards high-intensity beams in RHIC  

SciTech Connect

Proton bunch intensities in RHIC are planned to be increased from 2 {center_dot} 10{sup 11} to 3 {center_dot} 10{sup 11} protons per bunch to increase the luminosity, together with head-on beam-beam compensation using electron lenses. To study the feasibility of the intensity increase, beam experiments are being performed. Recent experimental results are presented.

Montag C.; Ahrens, L.; Brennan, J.M.; Blaskiewicz, M.; Drees, A.; Fischer, W.; Hayes, T.; Huang, H.; Mernick, K.; Robert-Demolaize, G.; Smith, K.; Than, R.; Thieberger, P.; Yip, K.; Zeno, K.; Zhang, S.Y.

2012-05-20T23:59:59.000Z

166

High intensity production of high and medium charge state uraniumand other heavy ion beams with VENUS  

SciTech Connect

The next generation, superconducting ECR ion source VENUS(Versatile ECR ion source for NUclear Science) started operation with 28GHzmicrowave heating in 2004. Since then it has produced world recordion beam intensities. For example, 2850 e mu A of O6+, 200 e mu A of U33+or U34+, and in respect to high charge state ions, 1 e mu A of Ar18+, 270e mu A of Ar16+, 28 e mu A of Xe35+ and 4.9 e mu A of U47+ have beenproduced. A brief overview of the latest developments leading to theserecord intensities is given and the production of high intensity uraniumbeams is discussed in more detail.

Leitner, Daniela; Galloway, Michelle L.; Loew, Timothy J.; Lyneis, Claude M.; Rodriguez, Ingrid Castro; Todd, Damon S.

2007-11-15T23:59:59.000Z

167

High energy XeBr electric discharge laser  

DOE Patents (OSTI)

A high energy XeBr laser for producing coherent radiation at 282 nm. The XeBr laser utilizes an electric discharge as the excitation source to minimize formation of molecular ions thereby minimizing absorption of laser radiation by the active medium. Additionally, HBr is used as the halogen donor which undergoes harpooning reactions with Xe.sub.M * to form XeBr*.

Sze, Robert C. (Santa Fe, NM); Scott, Peter B. (Los Alamos, NM)

1981-01-01T23:59:59.000Z

168

Modeling of high energy laser ignition of energetic materials  

SciTech Connect

We present a model for simulating high energy laser heating and ignition of confined energetic materials. The model considers the effect of irradiating a steel plate with long laser pulses and continuous lasers of several kilowatts and the thermal response of well-characterized high explosives for ignition. Since there is enough time for the thermal wave to propagate into the target and to create a region of hot spot in the high explosives, electron thermal diffusion of ultrashort (femto- and picosecond) lasing is ignored; instead, heat diffusion of absorbed laser energy in the solid target is modeled with thermal decomposition kinetic models of high explosives. Numerically simulated pulsed-laser heating of solid target and thermal explosion of cyclotrimethylenetrinitramine, triaminotrinitrobenzene, and octahydrotetranitrotetrazine are compared to experimental results. The experimental and numerical results are in good agreement.

Lee, Kyung-cheol; Kim, Ki-hong; Yoh, Jack J. [School of Mechanical and Aerospace Engineering, Seoul National University, Seoul, 151-742 (Korea, Republic of)

2008-04-15T23:59:59.000Z

169

Hot-electron production and suprathermal heat flux scaling with laser intensity from the two-plasmon-decay instability  

SciTech Connect

The fully kinetic reduced-description particle-in-cell (RPIC) method has been applied to simulations of two-plasmon-decay (TPD) instability, driven by crossed laser beams, in an inhomogeneous plasma for parameters consistent with recent direct-drive experiments related to laser-driven inertial fusion. The nonlinear saturated state is characterized by very spiky electric fields, with Langmuir cavitation occurring preferentially inside density channels produced by the ponderomotive beating of the crossed laser beams and the primary TPD Langmuir waves (LWs). The heated electron distribution function is, in all cases, bi-Maxwellian, with instantaneous hot-electron temperatures in the range 60-100 keV. The net hot-electron energy flux out of the system is a small fraction ({approx}1% to 2%) of the input laser intensity in these simulations. Scalings of the hot-electron temperature and suprathermal heat flux as functions of the laser intensity are obtained numerically from RPIC simulations. These simulations lead to the preliminary conclusion that Langmuir cavitation and collapse provide dissipation by producing suprathermal electrons, which stabilize the system in saturation and drive the LW spectrum to the small dissipation scales at the Landau cutoff. The Langmuir turbulence originates at an electron density 0.241 Multiplication-Sign the laser's critical density, where the crossed laser beams excite a 'triad' mode-a common forward LW plus a pair of backward LWs. Remnants of this 'triad' evolve in k-space and dominate the time-averaged energy spectrum. At times exceeding 10 ps, the excited Langmuir turbulence spreads toward lower densities. Comparisons of RPIC simulations with the extended Zakharov model are presented in appropriate regimes, and the necessary requirements for the validity of a quasi-linear Zakharov model (where the spatially averaged electron-velocity distribution is evolved) are verified by RPIC simulation results.

Vu, H. X. [University of California, San Diego, La Jolla, California 92093 (United States); DuBois, D. F. [Lodestar Research Corporation, Boulder, Colorado 80301 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Myatt, J. F. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Russell, D. A. [Lodestar Research Corporation, Boulder, Colorado 80301 (United States)

2012-10-15T23:59:59.000Z

170

400-Watt Electronic High-Bay Fixture for Metal-Halide High-Intensity Discharge Lighting  

Science Conference Proceedings (OSTI)

The product under assessment is an advanced lighting technology8212a 400-watt, metal-halide, electronic high-intensity discharge (HID) ballast technology designed to be operated as a stand-alone ballast or integrated as a fixture where the ballast becomes part of the fixture mechanical support system.

2008-06-12T23:59:59.000Z

171

Max Tech and Beyond: High-Intensity Discharge Lamps  

Science Conference Proceedings (OSTI)

High-intensity discharge (HID) lamps are most often found in industrial and commercial applications, and are the light source of choice in street and area lighting, and sports stadium illumination. HID lamps are produced in three types - mercury vapor (MV), high pressure sodium (HPS) and metal halide (MH). Of these, MV and MH are considered white-light sources (although the MV exhibits poor color rendering) and HPS produces a yellow-orange color light. A fourth lamp, low-pressure sodium (LPS), is not a HID lamp by definition, but it is used in similar applications and thus is often grouped with HID lamps. With the notable exception of MV which is comparatively inefficient and in decline in the US from both a sales and installed stock point of view; HPS, LPS and MH all have efficacies over 100 lumens per watt. The figure below presents the efficacy trends over time for commercially available HID lamps and LPS, starting with MV and LPS in 1930's followed by the development of HPS and MH in the 1960's. In HID lamps, light is generated by creating an electric arc between two electrodes in an arc tube. The particles in the arc are partially ionized, making them electrically conductive, and a light-emitting 'plasma' is created. This arc occurs within the arc tube, which for most HID lamps is enclosed within an evacuated outer bulb that thermally isolates and protects the hot arc tube from the surroundings. Unlike a fluorescent lamp that produces visible light through down-converting UV light with phosphors, the arc itself is the light source in an HID lamp, emitting visible radiation that is characteristic of the elements present in the plasma. Thus, the mixture of elements included in the arc tube is one critical factor determining the quality of the light emitted from the lamp, including its correlated color temperature (CCT) and color rendering index (CRI). Similar to fluorescent lamps, HID lamps require a ballast to start and maintain stable operating conditions, and this necessitates additional power beyond that used by the lamp itself. HID lamps offer important advantages compared to other lighting technologies, making them well suited for certain applications. HID lamps can be very efficient, have long operating lives, are relatively temperature-insensitive and produce a large quantity of light from a small package. For these reasons, HID lamps are often used when high levels of illumination are required over large areas and where operating and maintenance costs must be kept to a minimum. Furthermore, if the installation has a significant mounting height, high-power HID lamps can offer superior optical performance luminaires, reducing the number of lamps required to illuminate a given area. The indoor environments best suited to HID lamps are those with high ceilings, such as those commonly found in industrial spaces, warehouses, large retail spaces, sports halls and large public areas. Research into efficacy improvements for HID lighting technologies has generally followed market demand for these lamps, which is in decline for MV and LPS, has reached a plateau for HPS and is growing for MH. Several manufacturers interviewed for this study indicated that although solid-state lighting was now receiving the bulk of their company's R&D investment, there are still strong HID lamp research programs, which concentrate on MH technologies, with some limited amount of investment in HPS for specific niche applications (e.g., agricultural greenhouses). LPS and MV lamps are no longer being researched or improved in terms of efficacy or other performance attributes, although some consider MH HID lamps to be the next-generation MV lamp. Thus, the efficacy values of commercially available MV, LPS and HPS lamps are not expected to increase in the next 5 to 10 years. MH lamps, and more specifically, ceramic MH lamps are continuing to improve in efficacy as well as light quality, manufacturability and lamp life. Within an HID lamp, the light-producing plasma must be heated to sufficiently high temperatures to achieve high efficiencie

Scholand, Michael

2012-04-01T23:59:59.000Z

172

Apparatus for injecting high power laser light into a fiber optic cable  

DOE Patents (OSTI)

High intensity laser light is evenly injected into an optical fiber by the combination of a converging lens and a multisegment kinoform (binary optical element). The segments preferably have multi-order gratings on each which are aligned parallel to a radial line emanating from the center of the kinoform and pass through the center of the element. The grating in each segment causes circumferential (lateral) dispersion of the light, thereby avoiding detrimental concentration of light energy within the optical fiber.

Sweatt, William C. (Albuquerque, NM)

1997-01-01T23:59:59.000Z

173

Understanding High-Power Fiber-Optic Laser Beam Delivery  

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

High-Power Fiber-Optic Laser Beam Delivery High-Power Fiber-Optic Laser Beam Delivery The submitted manuscript has been authored by a contractor of the U.S. Government under contract No. W- 31-109-ENG-38. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes. Boyd V. Hunter and Keng H. Leong Argonne National Laboratory Technology Development Division Laser Applications Laboratory 9700 South Cass Avenue, Building 207 Argonne, Illinois 60439 Carl B. Miller, James F. Golden, Robert D. Glesias and Patrick J. Laverty U. S. Laser Corporation 825 Windham Court North P. O. Box 609 Wyckoff, New Jersey 07481 March 25, 1996 Manuscript to be submitted to Journal of Laser Applications

174

Design of high efficiency Mid IR QCL lasers  

E-Print Network (OSTI)

The proposed research is a study of designing high-efficiency Mid-IR quantum cascade lasers (QCL). This thesis explores "injector-less" designs for achieving lower voltage defects and improving wall plug efficiencies through ...

Hsu, Allen Long

2008-01-01T23:59:59.000Z

175

A high transmission analyzing magnet for intense high charge state beams  

DOE Green Energy (OSTI)

The low energy beam transport (LEBT) for VENUS will provide for extraction, mass analysis and transport to the axial injection line for the 88-Inch Cyclotron. The new LEBT was designed from the beginning to handle high intensity beams where space charge forces strongly affect the transmission. The magnet has a unique design with specially shaped poles to apply sextupole correction in both the horizontal and vertical plane.

Leitner, M.; Abbott, S.R.; Leitner, D.; Lyneis, C.

2002-06-11T23:59:59.000Z

176

High Power Lasers... Another approach to  

E-Print Network (OSTI)

Research Laboratory Washington, DC #12;2 Main points of the talk Fusion Energy based on lasers and direct employees, (900 PhDs + 400 MSc) · $800 M /year budget ·Field sites: · Washington DC (Main site) · Stennis (Hibachi) Amplifier Window Electron Beam Cathode Pulsed Power System Energy + ( Kr+ F2) ( KrF)* + F Kr

177

High average power diode pumped solid state lasers for CALIOPE  

Science Conference Proceedings (OSTI)

Diode pumping of solid state media offers the opportunity for very low maintenance, high efficiency, and compact laser systems. For remote sensing, such lasers may be used to pump tunable non-linear sources, or if tunable themselves, act directly or through harmonic crystals as the probe. The needs of long range remote sensing missions require laser performance in the several watts to kilowatts range. At these power performance levels, more advanced thermal management technologies are required for the diode pumps. The solid state laser design must now address a variety of issues arising from the thermal loads, including fracture limits, induced lensing and aberrations, induced birefringence, and laser cavity optical component performance degradation with average power loading. In order to highlight the design trade-offs involved in addressing the above issues, a variety of existing average power laser systems are briefly described. Included are two systems based on Spectra Diode Laboratory`s water impingement cooled diode packages: a two times diffraction limited, 200 watt average power, 200 Hz multi-rod laser/amplifier by Fibertek, and TRW`s 100 watt, 100 Hz, phase conjugated amplifier. The authors also present two laser systems built at Lawrence Livermore National Laboratory (LLNL) based on their more aggressive diode bar cooling package, which uses microchannel cooler technology capable of 100% duty factor operation. They then present the design of LLNL`s first generation OPO pump laser for remote sensing. This system is specified to run at 100 Hz, 20 nsec pulses each with 300 mJ, less than two times diffraction limited, and with a stable single longitudinal mode. The performance of the first testbed version will be presented. The authors conclude with directions their group is pursuing to advance average power lasers. This includes average power electro-optics, low heat load lasing media, and heat capacity lasers.

Comaskey, B.; Halpin, J.; Moran, B.

1994-07-01T23:59:59.000Z

178

HIGH INTENSITY LOW-ENERGY POSITRON SOURCE AT JEFFERSON  

SciTech Connect

We present a novel concept of a low-energy e{sup +} source with projected intensity on the order of 10{sup 10} slow e{sup +}/s. The key components of this concept are a continuous wave e{sup -} beam, a rotating positron-production target, a synchronized raster/anti-raster, a transport channel, and extraction of e{sup +} into a field-free area through a magnetic plug for moderation in a cryogenic solid. Components were designed in the framework of GEANT4-based (G4beamline) Monte Carlo simulation and TOSCA magnetic field calculation codes. Experimental data to demonstrate the effectiveness of the magnetic plug is presented.

Serkan Golge, Bogdan Wojtsekhowski, Branislav Vlahovic

2012-07-01T23:59:59.000Z

179

High-Voltage Power Supply System for Laser Isotope Separation  

SciTech Connect

This report presents several concepts for Laser High-Voltage Power Supply (HVPS) Systems for a Laser Isotope Separation facility. Selection of equipments and their arrangement into operational systems is based on proven designs and on application concepts now being developed. This report has identified a number of alternative system arrangements and has provided preliminary cost estimates for each. The report includes a recommendation for follow-on studies that will further define the optimum Laser HVPS Systems. Brief descriptions are given of Modulator/Regulator circuit trade-offs, system control interfaces, and their impact on costs.

Ketaily, E.C.; Buckner, R.P.; Uhrik, R.L.

1979-06-26T23:59:59.000Z

180

High pressure study of changes in energy and intensity of excitations in crystalline metal glyoximes  

SciTech Connect

The effect of high pressure has been measured on the energy and integrated intensity of electronic excitations of several layered crystals of glyoximes containing Ni, Pd, or Pt. Large changes in both energy and intensity were observed, both of which were completely reversible. The shifts in energy with pressure, are explained in terms of the relative spatial extent of the outer d and p orbitals of Ni, Pd, and Pt. The effects of back donation from the ligands and intensity borrowing from the higher energy charge transfer excitations are considered as possible causes of the observed intensity changes. It was concluded that intensity borrowing was the major cause of the observed changes.

Tkacz, M.; Drickamer, H.G.

1986-07-15T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" 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

Spacecraft Power Beaming Using High-Energy Lasers, Experimental Validation  

SciTech Connect

The lifetime of many spacecrafts are often limited by degradation of their electrical power subsystem, e.g. radiation-damaged solar arrays or failed batteries. Being able to beam power from terrestrial sites using high energy lasers, could alleviate this limitation, extending the lifetime of billions of dollars of satellite assets, as well as providing additional energy for electric propulsion that can be used for stationkeeping and orbital changes. In addition, extensive research at the Naval Postgraduate School (NPS) has shown the potential for annealing damaged solar cells using lasers. This paper describes that research and a proposed experiment to demonstrate the relevant concepts of high energy laser power beaming to an NPS-built and operated satellite. Preliminary results of ground experiment of laser illuminations of some of the solar panels of one of the spacecrafts are also presented.

Michael, Sherif [Naval Postgraduate School ECE Dep./Space Systems Academic Group, Monterey, CA 93943 (United States)

2008-04-28T23:59:59.000Z

182

High energy KrCl electric discharge laser  

SciTech Connect

A high energy KrCl laser for producing coherent radiation at 222 nm. Output energies on the order of 100 mJ per pulse are produced utilizing a discharge excitation source to minimize formation of molecular ions, thereby minimizing absorption of laser radiation by the active medium. Additionally, HCl is used as a halogen donor which undergoes a harpooning reaction with metastable Kr.sub.M * to form KrCl.

Sze, Robert C. (Santa Fe, NM); Scott, Peter B. (Los Alamos, NM)

1981-01-01T23:59:59.000Z

183

A non-intrusive beam power monitor for high power pulsed or continuous wave lasers  

DOE Patents (OSTI)

A system and method for monitoring the output of a laser is provided in which the output of a photodiode disposed in the cavity of the laser is used to provide a correlated indication of the laser power. The photodiode is disposed out of the laser beam to view the extraneous light generated in the laser cavity whose intensity has been found to be a direct correlation of the laser beam output power level. Further, the system provides means for monitoring the phase of the laser output beam relative to a modulated control signal through the photodiode monitor.

Hawsey, R.A.; Scudiere, M.B.

1991-05-29T23:59:59.000Z

184

A non-intrusive beam power monitor for high power pulsed or continuous wave lasers  

DOE Patents (OSTI)

A system for monitoring the output of a laser is provided in which the output of a photodiode disposed in the cavity of the laser is used to provide a correlated indication of the laser power. The photodiode is disposed out of the laser beam to view the extraneous light generated in the laser cavity whose intensity has been found to be a direct correlation of the laser beam output power level. Further, the system provides means for monitoring the phase of the laser output beam relative to a modulated control signal through the photodiode monitor. 4 figs.

Hawsey, R.A.; Scudiere, M.B.

1989-09-26T23:59:59.000Z

185

Experimental Investigation of the Reflection Mode Micro Laser Propulsion under Highly Frequent and Multi Pulse Laser  

SciTech Connect

Micro laser propulsion used for some space tasks of micro-satellites are preferred to providing small thrust and high specific impulse while keeping power consumption low. Most previous work on micro laser propulsion are about transmission mode (T-mode) using a CW laser. In this article, a pulsed fiber laser is used to study the micro laser propulsion performance under reflection mode. Multi pulse (ranged from 100 to 2000) tests are conducted on a double base propellant with the vacuum less than 10 Pa. The laser frequency is 20 kHz and two kinds of instantaneous power density 4.77x10{sup 6} W/cm{sup 2} and 2.39x10{sup 7} W/cm{sup 2} are used. It is found that the momentum coupling coefficient C{sub m} and the mean thrust F increases with the increasing pulse numbers, which is different to the previous work. By adjusting the irradiation time T, it is easy to get a large mean thrust, up to mN. When the energy density is the same, C{sub m}, I{sub sp}, F and {eta} increase with the increasing power density. Also I{sub sp} and {eta} are very low, laser ablation is insufficiently under the current condition. 3D Morphology of the ablation hole is obtained by confocal microscope for the first time.

Zhang Xinghua; Cai Jian [Microelectronic Equipment Technology Department, Institute of Microelectronics of the Chinese Academy of Sciences, Beijing, 100029 (China); Li Long [Department of Modern Mechanics, University of Science and Technology of China, Hefei, 230027 (China)

2011-11-10T23:59:59.000Z

186

Uniform irradiation of adjustable target spots in high-power laser driver  

Science Conference Proceedings (OSTI)

For smoothing and shaping the on-target laser patterns flexibly in high-power laser drivers, a scheme has been developed that includes a zoom lens array and two-dimensional smoothing by spectral dispersion (SSD). The size of the target pattern can be controlled handily by adjusting the focal length of the zoom lens array, while the profile of the pattern can be shaped by fine tuning the distance between the target and the focal plane of the principal focusing lens. High-frequency stripes inside the pattern caused by beamlet interference are wiped off by spectral dispersion. Detailed simulations indicate that SSD works somewhat differently for spots of different sizes. For small spots, SSD mainly smooths the intensity modulation of low-to-middle spatial frequency, while for large spots, SSD sweeps the fine speckle structure to reduce nonuniformity of middle-to-high frequency. Spatial spectra of the target patterns are given and their uniformity is evaluated.

Jiang Xiujuan; Li Jinghui; Li Huagang; Li Yang; Lin Zunqi

2011-09-20T23:59:59.000Z

187

Dichroic beamsplitter for high energy laser diagnostics  

DOE Patents (OSTI)

Wavefront control techniques are provided for the alignment and performance optimization of optical devices. A Shack-Hartmann wavefront sensor can be used to measure the wavefront distortion and a control system generates feedback error signal to optics inside the device to correct the wavefront. The system can be calibrated with a low-average-power probe laser. An optical element is provided to couple the optical device to a diagnostic/control package in a way that optimizes both the output power of the optical device and the coupling of the probe light into the diagnostics.

LaFortune, Kai N (Livermore, CA); Hurd, Randall (Tracy, CA); Fochs, Scott N (Livermore, CA); Rotter, Mark D (San Ramon, CA); Hackel, Lloyd (Livermore, CA)

2011-08-30T23:59:59.000Z

188

High power semiconductor laser diode arrays  

SciTech Connect

The cw optical power obtainable from semiconductor laser diodes has been extended to unprecedented levels in recent years through the use of multistripe arrays. By spreading out the optical power with more than 100 stripes, single-facet, cw output in exces of 5 Watts has been demonstrated, and 500 mW cw is now commercially available. Recent improvements to array performance include: arrays up to 1 cm wide that generates quasi-cw (150 usec pulse) output in excesss of 11 Watts, and a novel device structure which produces up to 215 mW cw in a single diffraction limited lobe.

Cross, P.S.

1986-08-15T23:59:59.000Z

189

Liquid lithium target as a high intensity, high energy neutron source  

DOE Patents (OSTI)

This invention provides a target jet for charged particles. In one embodiment the charged particles are high energy deuterons that bombard the target jet to produce high intensity, high energy neutrons. To this end, deuterons in a vacuum container bombard an endlessly circulating, free-falling, sheet-shaped, copiously flowing, liquid lithium jet that gushes by gravity from a rectangular cross-section vent on the inside of the container means to form a moving web in contact with the inside wall of the vacuum container. The neutrons are produced via break-up of the beam in the target by stripping, spallation and compound nuclear reactions in which the projectiles (deuterons) interact with the target (Li) to produce excited nuclei, which then "boil off" or evaporate a neutron.

Parkin, Don M. (Los Alamos, NM); Dudey, Norman D. (Glen Ellyn, IL)

1976-01-01T23:59:59.000Z

190

Direct High-Power Laser Acceleration of Ions for Medical Applications  

Science Conference Proceedings (OSTI)

Theoretical investigations show that linearly and radially polarized multiterawatt and petawatt laser beams, focused to subwavelength waist radii, can directly accelerate protons and carbon nuclei, over micron-size distances, to the energies required for hadron cancer therapy. Ions accelerated by radially polarized lasers have generally a more favorable energy spread than those accelerated by linearly polarized lasers of the same intensity.

Salamin, Yousef I. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Physics Department, American University of Sharjah, POB 26666, Sharjah (United Arab Emirates); Harman, Zoltan; Keitel, Christoph H. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany)

2008-04-18T23:59:59.000Z

191

Technical challenges for the future of high energy lasers  

SciTech Connect

The Solid-State, Heat-Capacity Laser (SSHCL) program at Lawrence Livermore National Laboratory is a multi-generation laser development effort scalable to the megawatt power levels with current performance approaching 100 kilowatts. This program is one of many designed to harness the power of lasers for use as directed energy weapons. There are many hurdles common to all of these programs that must be overcome to make the technology viable. There will be a in-depth discussion of the general issues facing state-of-the-art high energy lasers and paths to their resolution. Despite the relative simplicity of the SSHCL design, many challenges have been uncovered in the implementation of this particular system. An overview of these and their resolution are discussed. The overall system design of the SSHCL, technological strengths and weaknesses, and most recent experimental results will be presented.

LaFortune, K N; Hurd, R L; Fochs, S N; Rotter, M D; Pax, P H; Combs, R L; Olivier, S S; Brase, J M; Yamamoto, R M

2007-01-10T23:59:59.000Z

192

Bright High Average Power Table-top Soft X-Ray Lasers  

Science Conference Proceedings (OSTI)

We have demonstrated the generation of bright soft x-ray laser pulses with record-high average power from compact plasma amplifiers excited by ultrafast solid state lasers. These lasers have numerous applications in nanoscience and nanotechnology.

Rocca, Jorge [Colorado State University, Fort Collins; Reagan, Brendon [Colorado State University, Fort Collins; Wernsing, Keith [Colorado State University, Fort Collins; Luther, Brad [Colorado State University, Fort Collins; Curtis, Alden [Colorado State University, Fort Collins; Nichols,, Anthony [Colorado State University, Fort Collins; Wang, Yong [Colorado State University, Fort Collins; Alessi, David [Colorado State University, Fort Collins; Martz, Dale [Colorado State University, Fort Collins; Yin, Liang [Colorado State University, Fort Collins; Wang, Shoujun [Colorado State University, Fort Collins; Berrill, Mark A [ORNL; Furch, Federico [Colorado State University, Fort Collins; Woolston, Mark [Colorado State University, Fort Collins; Patel, Dinesh [Colorado State University, Fort Collins; Marconi, Mario [Colorado State University, Fort Collins; Menoni, Carmen [Colorado State University, Fort Collins

2012-01-01T23:59:59.000Z

193

Relative x-ray backlighter intensity comparison of ti and ti/sc combination foils driven in double-sided and single-sided laser configuration  

SciTech Connect

Use of multiple backlighter foils and/or double-sided laser interaction geometry with backlit imaging can result in improved backlighter efficiency. An experimental comparison of backlighter intensity for Ti foils and Ti/Sc combination foils in both the one-sided and double-sided laser-interaction configuration is presented. Spectrally-integrated framing camera images show intensity contributions of front and rear backlighter surfaces for both foil types. Analysis of time-resolved x-ray spectra collected from foil targets show the relative contribution of Ti and Sc 2-1 He-like resonance lines to the total backlighter intensity.

Bullock, A B; Landen, O L; Bradley, D K

2000-06-05T23:59:59.000Z

194

Device for providing high-intensity ion or electron beam  

SciTech Connect

A thin film of a low-thermionic-work-function material is maintained on the cathode of a device for producing a high-current, low-pressure gas discharge by means of sputter deposition from an auxiliary electrode. The auxiliary electrode includes a surface with a low-work-function material, such as thorium, uranium, plutonium or one of the rare earth elements, facing the cathode but at a disposition and electrical potential so as to extract ions from the gas discharge and sputter the low-work-function material onto the cathode. By continuously replenishing the cathode film, high thermionic emissions and ion plasmas can be realized and maintained over extended operating periods.

McClanahan, Edwin D. (Richland, WA); Moss, Ronald W. (Richland, WA)

1977-01-01T23:59:59.000Z

195

Production of intense highly charged ion beams with SERSE  

E-Print Network (OSTI)

The source SERSE is operational at LNS since June 1998 and many improvements have been carried out in this period. The frequency has been increased from 14.5 GHz to 18 GHz and the use of two frequency heating has given positive results. Metallic ion production has been tested by means of a high temperature oven and the preliminary results are described. Tests of magnetic field scaling and frequency scaling have confirmed the results of previous tests with SC-ECRIS at lower frequency and seems to suggest that the upgrading of the source to higher frequency may be considered.

Gammino, S; Ciavola, G; Castro, M; Chines, F; Marletta, S; Melin, G; Briand, P; Girard, A; Ludwig, P; Seyfert, P; Guillaume, D

1999-01-01T23:59:59.000Z

196

High removal rate laser-based coating removal system  

DOE Patents (OSTI)

A compact laser system that removes surface coatings (such as paint, dirt, etc.) at a removal rate as high as 1000 ft.sup.2 /hr or more without damaging the surface. A high repetition rate laser with multiple amplification passes propagating through at least one optical amplifier is used, along with a delivery system consisting of a telescoping and articulating tube which also contains an evacuation system for simultaneously sweeping up the debris produced in the process. The amplified beam can be converted to an output beam by passively switching the polarization of at least one amplified beam. The system also has a personal safety system which protects against accidental exposures.

Matthews, Dennis L. (Moss Beach, CA); Celliers, Peter M. (Berkeley, CA); Hackel, Lloyd (Livermore, CA); Da Silva, Luiz B. (Danville, CA); Dane, C. Brent (Livermore, CA); Mrowka, Stanley (Richmond, CA)

1999-11-16T23:59:59.000Z

197

High Velocity Laser Accelerated Deposition (HVLAD)  

... thus producing a very broad range of advanced high-temperature and corrosion ... from stress corrosion cracking, corrosion fatigue, hydrogen ...

198

High-intensity, high-brightness polarized and unpolarized beam production in charge-exchange collisions  

DOE Green Energy (OSTI)

Basic limitations on the high-intensity H{sup -} ion beam production were experimentally studied in charge-exchange collisions of the neutral atomic hydrogen beam in the Na-vapour jet ionizer cell. These studies are the part of the polarized source upgrade (to 10 mA peak current and 85% polarization) project for RHIC. In the source the atomic hydrogen beam of a 5-10 keV energy and total (equivalent) current up to 5 A is produced by neutralization of proton beam in pulsed hydrogen gas target. Formation of the proton beam (from the surface of the plasma emitter with a low transverse ion temperature {approx}0.2 eV) is produced by four-electrode spherical multi-aperture ion-optical system with geometrical focusing. The hydrogen atomic beam intensity up to 1.0 A/cm{sup 2} (equivalent) was obtained in the Na-jet ionizer aperture of a 2.0 cm diameter. At the first stage of the experiment H-beam with 36 mA current, 5 keV energy and {approx}1.0 cm {center_dot} mrad normalized emittance was obtained using the flat grids and magnetic focusing.

Zelenski, A.; Ritter, J.; Zubets, V.; Steski, D.; Atoian, G.; Davydenko, V.; Ivanov, A.; Kolmogorov, A.

2011-03-28T23:59:59.000Z

199

High-Intensity Plasma Glass Melter Final Technical Report  

Science Conference Proceedings (OSTI)

The purpose of this project was to demonstrate the energy efficiency and reduced emissions that can be obtained with a dual torch DC plasma transferred arc-melting system. Plasmelt Glass Technologies, LLC was formed to solicit and execute the project, which utilize a full-scale test melter system. The system is similar to the one that was originally constructed by Johns Manville, but Plasmelt has added significant improvements to the torch design and melter system that has extended the original JM short torch lives. The original JM design has been shown to achieve melt rates 5 to 10 times faster than conventional gas or electric melting, with improved energy efficiency and reduced emissions. This project began on 7/28/2003 and ended 7/27/06. A laboratory scale melter was designed, constructed, and operated to conduct multiple experimental melting trials on various glass compositions. Glass quality was assessed. Although the melter design is generic and equally applicable to all sectors within the glass industry, the development of this melter has focused primarily on fiberglass with additional exploratory melting trials of frits, specialty, and minerals-melting applications. Throughput, energy efficiency, and glass quality have been shown to be heavily dependent on the selected glass composition. During this project, Plasmelt completed the proof-of-concept work in our Boulder, CO Lab to show the technical feasibility of this transferred-arc plasma melter. Late in the project, the work was focused on developing the processes and evaluating the economic viability of plasma melting aimed at the specific glasses of interest to specific client companies. Post project work is on going with client companies to address broader non-glass materials such as refractories and industrial minerals. Exploratory melting trials have been conducted on several glasses of commercial interest including: C-glass, E-glass, S-Glass, AR-Glass, B-glass, Lighting Glass, NE-Glass, and various frits. Exploratory melts of non-glassy materials, such as wollastonite, zirconium silicate, and alumino-silicate melts were successfully done indicating that plasma melting has potential application beyond glass. Experimental results were generated that show the high quality of plasma-melted fiberglass compositions, such as E-glass, can result in good fiberizing performance. Fiberizing performance and tensile strength data were achieved during the project to support this conclusion. High seed counts are a feature of the current lab scale melter and must be dealt with via other means, since fining work was outside the scope of this project.

Gonterman, J. Ronald; Weinstein, Michael A.

2006-10-27T23:59:59.000Z

200

High Rate Laser Pitting Technique for Solar Cell Texturing  

SciTech Connect

High rate laser pitting technique for solar cell texturing Efficiency of crystalline silicon solar cells can be improved by creating a texture on the surface to increase optical absorption. Different techniques have been developed for texturing, with the current state-of-the-art (SOA) being wet chemical etching. The process has poor optical performance, produces surfaces that are difficult to passivate or contact and is relatively expensive due to the use of hazardous chemicals. This project shall develop an alternative process for texturing mc-Si using laser micromachining. It will have the following features compared to the current SOA texturing process: -Superior optical surfaces for reduced front-surface reflection and enhanced optical absorption in thin mc-Si substrates -Improved surface passivation -More easily integrated into advanced back-contact cell concepts -Reduced use of hazardous chemicals and waste treatment -Similar or lower cost The process is based on laser pitting. The objective is to develop and demonstrate a high rate laser pitting process which will exceed the rate of former laser texturing processes by a factor of ten. The laser and scanning technologies will be demonstrated on a laboratory scale, but will use inherently technologies that can easily be scaled to production rates. The drastic increase in process velocity is required for the process to be implemented as an in-line process in PV manufacturing. The project includes laser process development, development of advanced optical systems for beam manipulation and cell reflectivity and efficiency testing. An improvement of over 0.5% absolute in efficiency is anticipated after laser-based texturing. The surface textures will be characterized optically, and solar cells will be fabricated with the new laser texturing to ensure that the new process is compatible with high-efficiency cell processing. The result will be demonstration of a prototype process that is suitable for scale-up to a production tool and process. The developed technique will have an reducing impact on product pricing. As efficiency has a substantial impact on the economics of solar cell production due to the high material cost content; in essence, improved efficiency through cost-effective texturing reduces the material cost component since the product is priced in terms of $/W. The project is a collaboration between Fraunhofer USA, Inc. and a c-Si PV manufacturer.

Hans J. Herfurth; Henrikki Pantsar

2013-01-10T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" 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.


201

Guiding of Intense Laser Pulses in Efficient End-pumped Plasma Channels Generated by Self-guiding in Ar and H2 Clusters  

Science Conference Proceedings (OSTI)

We demonstrate that self-guiding of intense short pulses in clustered gases can be utilized to generate long plasma channels, which upon expansion form waveguides suitable for propagation of laser pulses at high intensity. This scheme has several advantages over waveguide-generation in non-clustered gases. The absorption of energy by the target depends on the size of the clusters and not on the average density of the gas, which allows greater control of the density encountered by the guided pulse. In particular, electron densities less than 1018 cm-3 are feasible. Moreover, since clusters absorb sub-picosecond pulses very efficiently, channel generation by an auxiliary long-pulse laser is no longer necessary and a considerably simpler setup suffices. The problem of taper at the channel entrance, an old bugbear of side-pumped waveguides in gases, is shown to be significantly reduced. Evidence will be presented of waveguide generation in gases of argon and hydrogen clusters, using different cryogenic sources. A slit source is used for argon, and waveguides 1017 Wcm-2 were guided. The results of a propagation code suggest that even longer channels are well within experimental reach. Argon, however, has the disadvantage that a super-intense pulse would likely produce further ionization, and hence suffer ionization induced defocusing. Hydrogen clusters, which can easily be fully ionized, were formed using a more efficient conical nozzle cooled to 90 K, limiting maximum waveguide lengths to < 3 mm. Though these channels are short, there is no obvious reason why a longer target would not allow longer waveguides to be generated, and the experiments demonstrate the utility of this novel scheme.

Kumarappan, V.; Kim, K.-Y.; Milchberg, H.M. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States); Antonsen, T.M. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742 (United States)

2004-12-07T23:59:59.000Z

202

Ionization of oriented carbonyl sulfide molecules by intense circularly polarized laser pulses  

Science Conference Proceedings (OSTI)

We present combined experimental and theoretical results on strong-field ionization of oriented carbonyl sulfide molecules by circularly polarized laser pulses. The obtained molecular frame photoelectron angular distributions show pronounced asymmetries perpendicular to the direction of the molecular electric dipole moment. These findings are explained by a tunneling model invoking the laser-induced Stark shifts associated with the dipoles and polarizabilities of the molecule and its unrelaxed cation. The focus of the present article is to understand the strong-field ionization of one-dimensionally-oriented polar molecules, in particular asymmetries in the emission direction of the photoelectrons. In the following article [Phys. Rev. A 83, 023406 (2011)] the focus is to understand strong-field ionization from three-dimensionally-oriented asymmetric top molecules, in particular the suppression of electron emission in nodal planes of molecular orbitals.

Dimitrovski, Darko; Abu-samha, Mahmoud; Madsen, Lars Bojer; Filsinger, Frank; Meijer, Gerard; Kuepper, Jochen [Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin (Germany); Holmegaard, Lotte; Kalhoej, Line [Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Nielsen, Jens H. [Department of Physics, Aarhus University, DK-8000 Aarhus C (Denmark); Stapelfeldt, Henrik [Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C (Denmark)

2011-02-15T23:59:59.000Z

203

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

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

Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Researchers at Berkeley Lab have been exploring the ways coherent synchrotron radiation (CSR) is generated in electron storage rings when femtosecond lasers are used to carve out ultrafast x-ray pulses by femtoslicing (see "Tailored Terahertz Pulses from a Laser-Modulated Electron Beam"). In their most recent work, the researchers reported the first observation of seeding an instability of the electron beam by the laser, and they presented a physical model that shows how this occurs under the proper conditions. Such a mechanism makes it possible to control the instability onset and to exploit its gain for the generation of pulses of terahertz CSR of unprecedented power. Terahertz radiation with a wavelength from about 1 cm to about 100 microns between the microwave and the infrared would provide access to a large number of fundamental phenomena. To mention only some of them: excited electrons orbit, small molecules rotate, proteins vibrate, superconducting energy gaps resonate, and gaseous and solid-state plasmas oscillate at terahertz frequencies. But generating terahertz radiation is ordinarily a challenging task for any kind of source, including storage-ring-based synchrotron light sources. The new findings by the ALS group could represent a significant step toward satisfying the need for powerful terahertz sources.

204

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

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

Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Laser Seeding Yields High-Power Coherent Terahertz Radiation Print Researchers at Berkeley Lab have been exploring the ways coherent synchrotron radiation (CSR) is generated in electron storage rings when femtosecond lasers are used to carve out ultrafast x-ray pulses by femtoslicing (see "Tailored Terahertz Pulses from a Laser-Modulated Electron Beam"). In their most recent work, the researchers reported the first observation of seeding an instability of the electron beam by the laser, and they presented a physical model that shows how this occurs under the proper conditions. Such a mechanism makes it possible to control the instability onset and to exploit its gain for the generation of pulses of terahertz CSR of unprecedented power. Terahertz radiation with a wavelength from about 1 cm to about 100 microns between the microwave and the infrared would provide access to a large number of fundamental phenomena. To mention only some of them: excited electrons orbit, small molecules rotate, proteins vibrate, superconducting energy gaps resonate, and gaseous and solid-state plasmas oscillate at terahertz frequencies. But generating terahertz radiation is ordinarily a challenging task for any kind of source, including storage-ring-based synchrotron light sources. The new findings by the ALS group could represent a significant step toward satisfying the need for powerful terahertz sources.

205

Initial Results of the New High Intensity Electron Gun at the...  

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

INITIAL RESULTS OF THE NEW HIGH INTENSITY ELECTRON GUN AT THE ARGONNE WAKEFIELD ACCELERATOR * M.E. Conde, W. Gai, R. Konecny, J.G. Power, P. Schoessow, X. Sun, ANL, Argonne, IL...

206

Resonant Auger decay of the core-excited C{sup *}O molecule in intense x-ray laser fields  

SciTech Connect

The dynamics of the resonant Auger (RA) process of the core-excited C*O(1s{sup -1}{pi}*,v{sub r}=0) molecule in an intense x-ray laser field is studied theoretically. The theoretical approach includes the analog of the conical intersections of the complex potential energy surfaces of the ground and 'dressed' resonant states due to intense x-ray pulses, taking into account the decay of the resonance and the direct photoionization of the ground state, both populating the same final ionic states coherently, as well as the direct photoionization of the resonance state itself. The light-induced nonadiabatic effect of the analog of the conical intersections of the resulting complex potential energy surfaces gives rise to strong coupling between the electronic, vibrational, and rotational degrees of freedom of the diatomic CO molecule. The interplay of the direct photoionization of the ground state and of the decay of the resonance increases dramatically with the field intensity. The coherent population of a final ionic state via both the direct photoionization and the resonant Auger decay channels induces strong interference effects with distinct patterns in the RA electron spectra. The individual impact of these physical processes on the total electron yield and on the CO{sup +}(A {sup 2}{Pi}) electron spectrum are demonstrated.

Demekhin, Philipp V.; Chiang, Ying-Chih; Cederbaum, Lorenz S. [Theoretische Chemie, Physikalisch-Chemisches Institut, Universitaet Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany)

2011-09-15T23:59:59.000Z

207

High Voltage Laboratory Testing of Femtosecond Laser Lightning Diversion  

Science Conference Proceedings (OSTI)

Lightning strikes cost the electric power industry an estimated 1 billion dollars annually in damage and lost revenue. One possible way of protecting critical and susceptible facilities from lightning strikes is to use lasers to trigger and divert lightning along a predetermined path. This report describes laboratory research on the use of ultrashort UV pulses and near IR pulses to trigger high voltage discharge.

1998-12-09T23:59:59.000Z

208

Self-focusing of intense high frequency electromagnetic waves in a collisional magnetoactive plasma  

Science Conference Proceedings (OSTI)

The self-focusing of an intense electromagnetic beam in a collisional magnetoactive plasma has been investigated by the perturbation method. Considering the relativistic and ponderomotive nonlinearities and the first three terms of perturbation expansion for the electron density and velocity, the nonlinear wave equation is obtained. This wave equation is solved by applying the source dependent expansion method and the evolution of electromagnetic beam spot-size is discussed. It is shown that the laser spot-size decreases with increasing the collision frequency and external magnetic field strength.

Niknam, A. R.; Hashemzadeh, M. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Evin, Tehran (Iran, Islamic Republic of); Aliakbari, A.; Majedi, S. [Physics Department, Faculty of Science, Tafresh University, Tafresh (Iran, Islamic Republic of); Haji Mirzaei, F. [Physics Department, Islamic Azad University, Arak Branch, Arak (Iran, Islamic Republic of)

2011-11-15T23:59:59.000Z

209

Time-dependent unitary perturbation theory for intense laser driven molecular orientation  

E-Print Network (OSTI)

We apply a time-dependent perturbation theory based on unitary transformations combined with averaging techniques, on molecular orientation dynamics by ultrashort pulses. We test the validity and the accuracy of this approach on LiCl described within a rigid-rotor model and find that it is more accurate than other approximations. Furthermore, it is shown that a noticeable orientation can be achieved for experimentally standard short laser pulses of zero time average. In this case, we determine the dynamically relevant parameters by using the perturbative propagator, that is derived from this scheme, and we investigate the temperature effects on the molecular orientation dynamics.

D. Sugny; A. Keller; O. Atabek; D. Daems; S. Guérin; H. R. Jauslin

2004-01-07T23:59:59.000Z

210

Application of High Powered Lasers to Perforated Completions  

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

Congress on Applications of Laser & Electro-Optics Congress on Applications of Laser & Electro-Optics October 13 - 16, 2003, Jacksonville, Florida Application of High Powered Lasers to Perforated Completions Zhiyue Xu, Claude B. Reed and Keng H. Leong Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 R. A. Parker Parker Geoscience Consulting, LLC, 6346 Secrest Street, Arvada, CO 80403 R. M. Graves, Petroleum Engineering Department, Colorado School of Mines, Golden, CO 80401 ABSTRACT As part of the process of drilling an oil or gas well, a steel production casing is often inserted to the bottom of the well and sealed with cement against the productive formation. Openings must be made through the steel casing wall and cement and into the rock formation to allow formation fluid to enter the well. Conventionally, a perforator is

211

Pulsed laser processing of high temperature superconducting thin films  

SciTech Connect

Systematic studies of the effects of pulsed laser deposition processing parameters on plume dynamics and resultant film properties have been performed. Plume angular distributions, cos{sup m}({theta}), were observed to be variable between 1 > m > 10 depending on laser energy density and spot size. Under optimized conditions, epitaxial, superconducting thin films could be grown in-situ on a variety of single-crystal substrates. High quality, 200 nm thick films were obtained at deposition rates approaching 15 nm/sec. Additionally, the patterning of YBa{sub 2}Cu{sub 3}O{sub 7-x} thin films has been achieved by a process which combines thermal oxygen diffusion and laser annealing. This process is performed under relatively mild conditions which allows the structural integrity of the films to be preserved. 9 refs., 6 figs.

Muenchausen, R.E.; Dye, R.C.; Estler, R.C.; Foltyn, S.; Garcia, A.R.; Hubbard, K.M.; Nogar, N.S.; Wu, X.D. (Los Alamos National Lab., NM (USA)); Carim, A.; Mukherjee, A.; Brueck, S.R.J. (New Mexico Univ., Albuquerque, NM (USA))

1990-01-01T23:59:59.000Z

212

STATUS OF SLOW EXTRACTION OF HIGH INTENSITY PROTONS FROM BROOKHAVEN'S AGS.  

SciTech Connect

The Brookhaven AGS third integer resonant extraction system allows the AGS to provide high quality, high intensity 25.5 GeV/c proton beams simultaneously to four target stations and as many as 8 experiments. With the increasing intensities (over 7 x 10{sup 13} protons/pulse) and associated longer spill periods (2.4 to 3 seconds long), we continue to run with low losses and high quality low modulation continuous current beams. We have an active program of high energy physics experiments, including the high precision measurement of the muons magnetic moment [1] and the discovery of the rare Kaon decay, K+ {yields} {pi} + {nu}{bar {nu}} [2]. This program is continuing into the future with the rare symmetry violating process experiments [3] currently being designed to operate at the AGS. In this paper, we will present results from operation of high intensity slow extraction, the problems we encounter, and our solutions to those problems.

BROWN,K.A.AHRENS,L.BRENNAN,J.M.GLENN,J.W.ROSER,T.RUSSO,T.TSOUPAS,N.SMITH,K.ZENO,K.

2003-05-12T23:59:59.000Z

213

Method and system for modulation of gain suppression in high average power laser systems  

Science Conference Proceedings (OSTI)

A high average power laser system with modulated gain suppression includes an input aperture associated with a first laser beam extraction path and an output aperture associated with the first laser beam extraction path. The system also includes a pinhole creation laser having an optical output directed along a pinhole creation path and an absorbing material positioned along both the first laser beam extraction path and the pinhole creation path. The system further includes a mechanism operable to translate the absorbing material in a direction crossing the first laser beam extraction laser path and a controller operable to modulate the second laser beam.

Bayramian, Andrew James (Manteca, CA)

2012-07-31T23:59:59.000Z

214

Improved Heat Transfer and Performance of High Intensity Combustion Systems for Reformer Furnace Applications  

E-Print Network (OSTI)

Developments over the past fifteen years have evolved new short flame, high intensity (1,000,000 BTU/HR/ft3 ) combustion systems for industrial uses. Such systems produce a more uniform and higher heat flux than conventional low intensity systems and should enable substantial capital cost savings in new furnace applications. Recent performance improvements established from tests of high intensity combustion systems are described along with advances made in the analytical prediction of design performance. High intensity combustion systems can operate at zero excess air conditions without generating undesirable constituents in the exhaust. A more uniform gas temperature and gas emissivity renders modeling and design of the furnace radiant heat transfer section more realistic. 'Over-design' to allow for the less determinate conditions typical of low intensity, turbulent diffusion oil flame systems should be avoidable. A model has been set up and results generated which indicate the potentialities of the above premise. The application of vortex stabilized high intensity burners for reformer furnaces in the petrochemical industry is then reviewed and emphasized.

Williams, F. D. M.; Kondratas, H. M.

1983-01-01T23:59:59.000Z

215

Theoretical study of quantum molecular reaction dynamics and of the effects of intense laser radiation on a diatomic molecule  

DOE Green Energy (OSTI)

Within the very broad field of molecular dynamics, we have concentrated on two simple yet important systems. The systems are simple enough so that they are adequately described with a single Born-Oppenheimer potential energy surface and that the dynamics can be calculated accurately. They are important because they give insight into solving more complicated systems. First we discuss H + H/sub 2/ reactive scattering. We present an exact formalism for atom-diatom reactive scattering which avoids the problem of finding a coordinate system appropriate for both reactants and products. We present computational results for collinear H + H/sub 2/ reactive scattering which agree very well with previous calculations. We also present a coupled channel distorted wave Born approximation for atom-diatom reactive scattering which we show is a first order approximation to our exact formalism. We present coupled channel DWBA results for three dimensional H + H/sub 2/ reactive scattering. The second system is an isolated HF molecule in an intense laser field. Using classical trajectories and quantum dynamics, we look at energy absorbed and transition probabilities as a function of the laser pulse time and also averaged over the pulse time. Calculations are performed for both rotating and nonrotating HF. We examine one and two photon absorption about the fundamental frequency, multiphoton absorption, and overtone absorption. 127 references, 31 figures, 12 tables.

Dardi, P.S.

1984-11-01T23:59:59.000Z

216

Generation of high intensity rf pulses in the ionosphere by means of in situ compression  

SciTech Connect

We demonstrate, using a simple model, that high intensity pulses can be generated from a frequency-chirped modifier of much lower intensity by making use of the dispersive properties of the ionosphere. We show that a frequency-chirped pulse can be constructed so that its various components overtake each other at a prescribed height, resulting in large (up to one hundred times) transient intensity enhancements as compared to those achievable from a steady modifier operating at the same power. We examine briefly one possible application: the enhancement of plasma wave amplitudes which occurs as a result of the interaction of such a compressed pulse with pre-generated turbulence.

Cowley, S.C.; Perkins, F.W.; Valeo, E.J.

1993-04-01T23:59:59.000Z

217

Relativistic theory of frequency blue-shift of an intense ionizing laser beam in a plasma  

SciTech Connect

Frequency up-conversion of a laser beam causing gas ionization in a cavity is considered in a fully relativistic fashion. A simple ionization model, based on one-photon and multiphoton processes is used. A Vlasov fully nonlinear and ionization-model independent description is used in calculating the current which drives the wave equation for the electric field. The evolution of the wave frequency and its upshift are contrasted with those obtained in the nonrelativistic limit. It is found that the nonrelativistic treatment overestimates the frequency upshift by a factor more than two. Purely relativistic effects, such as a significant frequency modulation and a respective temporal pulse compression, are observed in the exact case.

Hizanidis, K.; Vomvoridis, J.L. [National Technical Univ. of Athens (Greece); Mendonca, J.T. [Instituto Superior Tecnico, Lisbon (Portugal). Dept. of Physics; Frantzeskakis, D.J. [Univ. of Athens (Greece). Dept. of Physics

1996-04-01T23:59:59.000Z

218

General approach to few-cycle intense laser interactions with complex atoms  

Science Conference Proceedings (OSTI)

A general ab initio and nonperturbative method to solve the time-dependent Schroedinger equation (TDSE) for the interaction of a strong attosecond laser pulse with a general atom, i.e., beyond the models of quasi-one-electron or quasi-two-electron targets, is described. The field-free Hamiltonian and the dipole matrices are generated using a flexible B-spline R-matrix method. This numerical implementation enables us to construct term-dependent, nonorthogonal sets of one-electron orbitals for the bound and continuum electrons. The solution of the TDSE is propagated in time using the Arnoldi-Lanczos method, which does not require the diagonalization of any large matrices. The method is illustrated by an application to the multiphoton excitation and ionization of Ne atoms. Good agreement with R-matrix Floquet calculations for the generalized cross sections for two-photon ionization is achieved.

Guan Xiaoxu; Zatsarinny, O.; Bartschat, K. [Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311 (United States); Schneider, B. I. [Physics Division, National Science Foundation, Arlington, Virginia 22230 (United States); Feist, J. [Institute for Theoretical Physics, Vienna University of Technology, A-1040 Vienna (Austria); Noble, C. J. [Department of Physics and Astronomy, Drake University, Des Moines, Iowa 50311 (United States); Computational Science and Engineering Department, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom)

2007-11-15T23:59:59.000Z

219

Spectral analysis of x-ray emission created by intense laser irradiation of copper materials  

Science Conference Proceedings (OSTI)

We have measured the x-ray emission, primarily from K{sub {alpha}},K{sub {beta}}, and He{sub {alpha}} lines, of elemental copper foil and 'foam' targets irradiated with a mid-10{sup 16} W/cm{sup 2} laser pulse. The copper foam at 0.1 times solid density is observed to produce 50% greater He{sub {alpha}} line emission than copper foil, and the measured signal is well-fit by a sum of three synthetic spectra generated by the atomic physics code FLYCHK. Additionally, spectra from both targets reveal characteristic inner shell K{sub {alpha}} transitions from hot electron interaction with the bulk copper. However, only the larger-volume foam target produced significant K{sub {beta}} radiation, confirming a lower bulk temperature in the higher volume sample.

Huntington, C. M.; Kuranz, C. C.; Drake, R. P. [Atmospheric, Oceanic, Space Science, University of Michigan, Ann Arbor, Michigan 48103 (United States); Malamud, G. [Atmospheric, Oceanic, Space Science, University of Michigan, Ann Arbor, Michigan 48103 (United States); Department of Physics, Nuclear Research Center - Negev, 84190 Beer-Sheva (Israel); Park, H.-S.; Maddox, B. R. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

2012-10-15T23:59:59.000Z

220

Physics of short-wavelength-laser design  

Science Conference Proceedings (OSTI)

The physics and design of vuv and soft x-ray lasers pumped by ICF class high intensity infrared laser drivers are described (for example, the SHIVA laser facility at LLNL). Laser design and physics issues are discussed in the case of a photoionization pumping scheme involving Ne II and line pumping schemes involving H-like and He-like neon.

Hagelstein, P.L.

1981-01-01T23:59:59.000Z

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221

Overview of the High Intensity Neutrino Source Linac R&D program at Fermilab  

SciTech Connect

The Fermilab High Intensity Neutrino Source (HINS) Linac R&D program is building a first-of-a-kind 60 MeV superconducting H- linac. The HINS Linac incorporates superconducting solenoids for transverse focusing, high power RF vector modulators for independent control of multiple cavities powered from a single klystron, and superconducting spoke-type accelerating cavities starting at 10 MeV. This will be the first application and demonstration of any of these technologies in a low-energy, high-intensity proton/H- linear accelerator. The HINS effort is relevant to a high intensity, superconducting H- linac that might serve the next generation of neutrino physics and muon storage ring/collider experiments. An overview of the HINS program, machine design, status, and outlook is presented.

Webber, R.C.; Appollinari, G.; Carneiro, J.P.; Gonin, I.; Hanna, B.; Hays, S.; Khabiboulline, T.; Lanfranco, G.; Madrak, R.L.; Moretti, A.; Nicol, T.; /Fermilab /Argonne

2008-09-01T23:59:59.000Z

222

High removal rate laser-based coating removal system  

Science Conference Proceedings (OSTI)

A compact laser system is disclosed that removes surface coatings (such as paint, dirt, etc.) at a removal rate as high as 1,000 ft{sup 2}/hr or more without damaging the surface. A high repetition rate laser with multiple amplification passes propagating through at least one optical amplifier is used, along with a delivery system consisting of a telescoping and articulating tube which also contains an evacuation system for simultaneously sweeping up the debris produced in the process. The amplified beam can be converted to an output beam by passively switching the polarization of at least one amplified beam. The system also has a personal safety system which protects against accidental exposures.

Matthews, D.L.; Celliers, P.M.; Hackel, L.; Da Silva, L.B.; Dane, C.B.; Mrowka, S.

1999-11-16T23:59:59.000Z

223

High average power magnetic modulator for metal vapor lasers  

DOE Patents (OSTI)

A three-stage magnetic modulator utilizing magnetic pulse compression designed to provide a 60 kV pulse to a copper vapor laser at a 4.5 kHz repetition rate is disclosed. This modulator operates at 34 kW input power. The circuit includes a step up auto transformer and utilizes a rod and plate stack construction technique to achieve a high packing factor.

Ball, Don G. (Livermore, CA); Birx, Daniel L. (Oakley, CA); Cook, Edward G. (Livermore, CA); Miller, John L. (Livermore, CA)

1994-01-01T23:59:59.000Z

224

Development of critical surface diagnostic based on the ion acoustic decay instability in laser produced high density plasma  

SciTech Connect

We have developed a large angle, UV collective Thomson scattering (CTS) diagnostic for high density, hot plasma relevant to laser fusion. The CTS measured the basic parameters of the plasma waves (frequency, wave number), or the spectral density function for selected wave vectors of plasma waves, which were excited by the IADI (ion acoustic parametric decay instability). It is a good diagnostic tool for a local electron temperature measurement. The electron temperature was estimated by measuring either ion acoustic wave or electron plasma wave in the laser intensity window of 1laser produced high density plasma.

Mizuno, K.; DeGroot, J.S.; Drake, R.P.; Seka, W.; Craxton, R.S.; Estabrook, K.G.

1994-12-31T23:59:59.000Z

225

High-order harmonic generation with Rydberg atoms by using an intense few-cycle pulse  

Science Conference Proceedings (OSTI)

We demonstrate that high-order harmonic generation (HHG) with both high cutoff frequency and high conversion efficiency can be realized by using a Rydberg atom in a few-cycle laser pulse. This is because a Rydberg state has a large electron orbital radius and small binding energy; therefore an electron in the Rydberg state can be ionized easily and accelerated directly toward the core under the interaction of a few-cycle laser pulse, leading to emission of harmonic photons. In this case, the tunneling process of the electron is not involved and, hence, the conversion efficiency and the cutoff frequency of harmonic generation can be higher than that predicted by the conventional three-step model.

Zhai Zhen; Fu Panming; Wang Bingbing [Laboratory of Optical Physics, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China); Zhu Qiren [Institute of Atomic and Molecular Physics, Jilin University, Changchun 130012 (China); Chen Jing [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Yan Zongchao [Department of Physics, University of New Brunswick, P.O. Box 4400, Fredericton, New Brunswick E3B 5A3 (Canada)

2011-04-15T23:59:59.000Z

226

The LLNL/UCLA high gradient inverse free electron laser  

SciTech Connect

We describe the Inverse Free Electron Accelerator currently under construction at Lawrence Livermore National Lab. Upon completion of this accelerator, high brightness electrons generated in the photoinjector blowout regime and accelerated to 50 MeV by S-band accelerating sections will interact with > 4 TW peak power Ti:Sapphire laser in a highly tapered 50 cm undulator and experience an acceleration gradient of > 200 MeV/m. We present the final design of the accelerator as well as the results of start-to-end simulations investigating preservation of beam quality and tolerances involved with this accelerator.

Moody, J. T.; Musumeci, P.; Anderson, G.; Anderson, S.; Betts, S.; Fisher, S.; Gibson, D.; Tremaine, A.; Wu, S. [Department of Physics and Astronomy, UCLA, Los Angeles California, 90095 (United States); Lawrence Livermore National Laboratory (United States)

2012-12-21T23:59:59.000Z

227

A high-intensity plasma-sputter heavy negative ion source  

SciTech Connect

A multicusp magnetic field plasma surface ion source, normally used for H/sup /minus//ion beam formation, has been modified for the generation of high-intensity, pulsed, heavy negative ion beams suitable for a variety of uses. To date, the source has been utilized to produce mA intensity pulsed beams of more than 24 species. A brief description of the source, and basic pulsed-mode operational data, (e.g., intensity versus cesium oven temperature, sputter probe voltage, and discharge pressure), are given. In addition, illustrative examples of intensity versus time and the mass distributions of ion beams extracted from a number of samples along with emittance data, are also presented. Preliminary results obtained during dc operation of the source under low discharge power conditions suggest that sources of this type may also be used to produce high-intensity (mA) dc beams. The results of these investigations are given, as well, and the technical issues that must be addressed for this mode of operation are discussed. 15 refs., 10 figs., 2 tabs.

Alton, G.D.; Mori, Y.; Takagi, A.; Ueno, A.; Fukumoto, S.

1989-01-01T23:59:59.000Z

228

The Evolution Towards Grids: Ten Years of High-Speed, Wide Area, Data Intensive Computing  

E-Print Network (OSTI)

1 The Evolution Towards Grids: Ten Years of High-Speed, Wide Area, Data Intensive Computing William aggregating and scheduling many resources. Data must be located and staged, cache and network capacity must and non-destructive imaging to supply real-time data to a remote, on-line, airframe structures expert who

229

Space charge measurements with a high intensity bunch at the Fermilab Main Injector  

SciTech Connect

For Project X, the Fermilab Main Injector will be required to operate with 3 times higher bunch intensity. The plan to study the space charge effects at the injection energy with intense bunches will be discussed. A multi-MW proton facility has been established as a critical need for the U.S. HEP program by HEPAP and P5. Utilization of the Main Injector (MI) as a high intensity proton source capable of delivering in excess of 2 MW beam power will require a factor of three increase in bunch intensity compared to current operations. Instabilities associated with beam loading, space charge, and electron cloud effects are common issues for high intensity proton machines. The MI intensities for current operations and Project X are listed in Table 1. The MI provides proton beams for Fermilab's Tevatron Proton-Antiproton Collider and MINOS neutrino experiments. The proposed 2MW proton facility, Project X, utilizes both the Recycler (RR) and the MI. The RR will be reconfigured as a proton accumulator and injector to realize the factor 3 bunch intensity increase in the MI. Since the energy in the RR and the MI at injection will be 6-8 GeV, which is relatively low, space charge effects will be significant and need to be studied. Studies based on the formation of high intensity bunches in the MI will guide the design and fabrication of the RF cavities and space-charge mitigation devices required for 2 MW operation of the MI. It is possible to create the higher bunch intensities required in the MI using a coalescing technique that has been successfully developed at Fermilab. This paper will discuss a 5 bunch coalescing scheme at 8 GeV which will produce 2.5 x 10{sup 11} protons in one bunch. Bunch stretching will be added to the coalescing process. The required RF parameters were optimized with longitudinal simulations. The beam studies, that have a goal of 85% coalescing efficiency, were started in June 2010.

Seiya, K.; Chase, B.; Dey, J.; Joireman, P.; Kourbanis, I.; /Fermilab; Yagodnitsyna, A.; /Novosibirsk State U.

2011-03-01T23:59:59.000Z

230

High intensity electron beam ion trap for charge state boosting of radioactive ion beams  

SciTech Connect

A high intensity electron beam ion trap under development at LLNL could be adapted for charge state boosting of radioactive ion beams, enabling a substantial reduction in the size and cost of a post-accelerator. We report estimates of the acceptance, ionization time, charge state distribution, emittance, and beam intensity for charge state boosting of radioactive ions in this device. The estimates imply that, for tin isotopes, over 10{sup 10} ions/s can be ionized to q = 40+ with an absolute emittance of approximately 1 (pi) mm mrad at an energy of 30 x q.k.

Marrs, R.

1998-09-30T23:59:59.000Z

231

A study of fast electron energy transport in relativistically intense laser-plasma interactions with large density scalelengths  

SciTech Connect

A systematic experimental and computational investigation of the effects of three well characterized density scalelengths on fast electron energy transport in ultra-intense laser-solid interactions has been performed. Experimental evidence is presented which shows that, when the density scalelength is sufficiently large, the fast electron beam entering the solid-density plasma is best described by two distinct populations: those accelerated within the coronal plasma (the fast electron pre-beam) and those accelerated near or at the critical density surface (the fast electron main-beam). The former has considerably lower divergence and higher temperature than that of the main-beam with a half-angle of {approx}20 Degree-Sign . It contains up to 30% of the total fast electron energy absorbed into the target. The number, kinetic energy, and total energy of the fast electrons in the pre-beam are increased by an increase in density scalelength. With larger density scalelengths, the fast electrons heat a smaller cross sectional area of the target, causing the thinnest targets to reach significantly higher rear surface temperatures. Modelling indicates that the enhanced fast electron pre-beam associated with the large density scalelength interaction generates a magnetic field within the target of sufficient magnitude to partially collimate the subsequent, more divergent, fast electron main-beam.

Scott, R. H. H.; Norreys, P. A. [Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Perez, F.; Baton, S. D. [LULI, Ecole Polytechnique, UMR 7605, CNRS/CEA/UPMC, Route de Saclay, 91128 Palaiseau (France); Santos, J. J.; Nicolai, Ph.; Hulin, S. [Univ. Bordeaux/CNRS/CEA, CELIA, UMR 5107, 33405 Talence (France); Ridgers, C. P. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Davies, J. R. [GoLP, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Lancaster, K. L.; Trines, R. M. G. M. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Bell, A. R.; Tzoufras, M. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Rose, S. J. [Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom)

2012-05-15T23:59:59.000Z

232

A GPGPU based program to solve the TDSE in intense laser fields through the finite difference approach  

E-Print Network (OSTI)

We present a General-purpose computing on graphics processing units (GPGPU) based computational program and framework for the electronic dynamics of atomic systems under intense laser fields. We present our results using the case of hydrogen, however the code is trivially extensible to tackle problems within the single-active electron (SAE) approximation. Building on our previous work, we introduce the first available GPGPU based implementation of the Taylor, Runge-Kutta and Lanczos based methods created with strong field ab-initio simulations specifically in mind; CLTDSE. The code makes use of finite difference methods and the OpenCL framework for GPU acceleration. The specific example system used is the classic test system; Hydrogen. After introducing the standard theory, and specific quantities which are calculated, the code, including installation and usage, is discussed in-depth. This is followed by some examples and a short benchmark between an 8 hardware thread (i.e logical core) Intel Xeon CPU and an ...

Broin, Cathal Ó

2013-01-01T23:59:59.000Z

233

A GPGPU based program to solve the TDSE in intense laser fields through the finite difference approach  

E-Print Network (OSTI)

We present a General-purpose computing on graphics processing units (GPGPU) based computational program and framework for the electronic dynamics of atomic systems under intense laser fields. We present our results using the case of hydrogen, however the code is trivially extensible to tackle problems within the single-active electron (SAE) approximation. Building on our previous work, we introduce the first available GPGPU based implementation of the Taylor, Runge-Kutta and Lanczos based methods created with strong field ab-initio simulations specifically in mind; CLTDSE. The code makes use of finite difference methods and the OpenCL framework for GPU acceleration. The specific example system used is the classic test system; Hydrogen. After introducing the standard theory, and specific quantities which are calculated, the code, including installation and usage, is discussed in-depth. This is followed by some examples and a short benchmark between an 8 hardware thread (i.e logical core) Intel Xeon CPU and an AMD 6970 GPU, where the parallel algorithm runs 10 times faster on the GPU than the CPU.

Cathal Ó Broin; L. A. A Nikolopoulos

2013-08-08T23:59:59.000Z

234

Modeling of large aperture third harmonic frequency conversion of high power Nd:glass laser systems  

SciTech Connect

To provide high-energy, high-power beams at short wavelengths for inertial-confinement-fusion experiments, we routinely convert the 1.053-{mu}m output of the Nova, Nd:phosphate-glass, laser system to its third-harmonic wavelength. We describe performance and conversion efficiency modeling of the 3 {times} 3 arrays potassium-dihydrogen-phosphate crystal plates used for type II/type II phase-matched harmonic conversion of Nova 0.74-m diameter beams, and an alternate type I/type II phase-matching configuration that improves the third-harmonic conversion efficiency. These arrays provide energy conversion of up to 65% and intensity conversion to 70%. 19 refs., 11 figs.

Henesian, M.A.; Wegner, P.J.; Speck, D.R.; Bibeau, C.; Ehrlich, R.B.; Laumann, C.W.; Lawson, J.K.; Weiland, T.L.

1991-03-13T23:59:59.000Z

235

Explosively pumped laser light  

DOE Patents (OSTI)

A single shot laser pumped by detonation of an explosive in a shell casing. The shock wave from detonation of the explosive causes a rare gas to luminesce. The high intensity light from the gas enters a lasing medium, which thereafter outputs a pulse of laser light to disable optical sensors and personnel.

Piltch, Martin S. (Los Alamos, NM); Michelotti, Roy A. (Los Alamos, NM)

1991-01-01T23:59:59.000Z

236

Development of fluorides for high power laser optics  

Science Conference Proceedings (OSTI)

The laser-assisted thermonuclear fusion program has significant needs for improved optical materials with high transmission in the ultraviolet, and with low values of nonlinear index of refraction. Lithium fluoride (LiF) possesses a combination of optical properties which are of potential use. Single-crystalline LiF is limited by low mechanical strength. In this program, we investigated the technique of press-forging to increase the mechanical strength. LiF single crystals were press-forged over the temperature range 300 to 600/sup 0/C to produce fine-grained polycrystalline material.

Ready, J.F.; Vora, H.

1980-07-01T23:59:59.000Z

237

HIGH-INTENSITY EFFECTS IN THE LONGITUDINAL MOTION OF STORED PARTICLE BEAMS  

SciTech Connect

A brief review is given of the various self-field phenomena associated with the longitudinal motion of particles in storage rings. Although there are some high-intensity phenomena for which the coupling of longitudinal and transverse motion is essential, such as, for example, the headtail effect; the great majority of high-intensity phenomena primarily involve either longitudinal or transverse degrees of freedom. In this review, we restrict our attention to phenomena which are essentially longitudinal in nature. It is convenient to consider separately the behavior of unbunched (coasting) and bunched (external RF system in operation) beams. Detailed experimental information on coasting beams has been obtained on the ISR, on the (old) CERN electron model CESAR, and on electron ring accelerators. All high-energy electron storage rings have bunched beams and, of course, so do synchrotrons, so that there are a large number of sources of experimental information about the longitudinal motion of bunched beams.

Sessler, Andrew M.

1973-02-01T23:59:59.000Z

238

Volume 35A, number4 PHYSICS LETTERS l4June 1971 ULTRA-INTENSE LASER RADIATION AS A POSSIBLE ENERGY BOOSTER FOR RELATIVISTIC CHARGED PARTICLE *  

E-Print Network (OSTI)

A new effect of large energy absorption is predicted for a relativistic charged particle interacting ‘parallel ’ with an ultra—intense laser beam. For 10 example, V/cm in a a distance 10MeV electron of 1.3 mm. can absorb energy of 40MeV from a laser beam of A = 1.06!1 and ~ 3 x10 In the production of coherent y-ray radiation with ~=e2~2/mw2. For Wrmin = IT, Emax2E. from a laser beam being backscattered (‘anti- Let K=Emax/mc2, then the final total particle parallel ’ scattering) by a high energy electron energy is given by Emax=(l ÷K)E 0. To achieve beam [e.g., 1,2], it demonstrates the unusual this condition, the minimum value of ~ required role of an electron beam as a frequency multi- is plier for laser radiation. In this communication 1/2 (w~=r) = (mcw/e)(yK). a new effect of opposite sense is described in the mm (3) case of ‘parallel ’ scattering. Namely, when a rela- For a Nd-glass laser, w = 1.8x 5Eo. 1015 Under rad/sec this(x = tivistic laser beam charged moving particle almost is together interacting in the withsame a 1.06 condition, ii). When ( max)e K=2, Emax = 1 MeV and (~min)e ‘ 3 X direction, an abnormally large amount of energy 10’°volt/cm for an electron and (Emax)p’~2GeV can be transferred from the radiation to the par- and (d min)p 5.5 x 1013 volt/cm for a proton. tide, as if the radiation behaves as an energy For experimental verification of this effect amplifier for the particle with an electron beam, some other effects must Since (np 0)11 =n, ~0.(A-A0) = 0 and nJ30 = be taken into consideration. in the case of ‘parallel ’ scattering, the i) Beam divergence. After scattering, the energy absorbed by the particle is simply as [2] particle is deflected by the radiation with a trans-— f15 I verse momentum Pm. Since Porn = 0, the angle of ~11 — L~0,11 / ~‘oJ ‘ ‘ / deflection is given by ~ “Pm/Pn • With Pm = where (6o)~=(1 _p~)-1and E e 2(A-A 2/2mc2,-(e/c)j A-Aol = ±(2rne)1/2andPn = energy absorbed if the particle was initially 0) at [2], we have rest. For a relativistic particle E 2, ~ —±2mc2~5E (4 1 and ~~°~ii —2y~.Therefore, 0>>rnc eq. (1) becomes

Yau Wa Chan

1971-01-01T23:59:59.000Z

239

Measurement and interpretation of threshold stress intensity factors for steels in high-pressure hydrogen gas.  

DOE Green Energy (OSTI)

Threshold stress intensity factors were measured in high-pressure hydrogen gas for a variety of low alloy ferritic steels using both constant crack opening displacement and rising crack opening displacement procedures. The sustained load cracking procedures are generally consistent with those in ASME Article KD-10 of Section VIII Division 3 of the Boiler and Pressure Vessel Code, which was recently published to guide design of high-pressure hydrogen vessels. Three definitions of threshold were established for the two test methods: K{sub THi}* is the maximum applied stress intensity factor for which no crack extension was observed under constant displacement; K{sub THa} is the stress intensity factor at the arrest position for a crack that extended under constant displacement; and K{sub JH} is the stress intensity factor at the onset of crack extension under rising displacement. The apparent crack initiation threshold under constant displacement, K{sub THi}*, and the crack arrest threshold, K{sub THa}, were both found to be non-conservative due to the hydrogen exposure and crack-tip deformation histories associated with typical procedures for sustained-load cracking tests under constant displacement. In contrast, K{sub JH}, which is measured under concurrent rising displacement and hydrogen gas exposure, provides a more conservative hydrogen-assisted fracture threshold that is relevant to structural components in which sub-critical crack extension is driven by internal hydrogen gas pressure.

Nibur, Kevin A.

2010-11-01T23:59:59.000Z

240

Experimental astrophysics with high power lasers and Z pinches  

SciTech Connect

With the advent of high energy density (HED) experimental facilities, such as high-energy lasers and fast Z-pinch, pulsed-power facilities, mm-scale quantities of matter can be placed in extreme states of density, temperature, and/or velocity. This has enabled the emergence of a new class of experimental science, HED laboratory astrophysics, wherein the properties of matter and the processes that occur under extreme astrophysical conditions can be examined in the laboratory. Areas particularly suitable to this class of experimental astrophysics include the study of opacities relevant to stellar interiors; equations of state relevant to planetary interiors; strong shock driven nonlinear hydrodynamics and radiative dynamics, relevant to supernova explosions and subsequent evolution; protostellar jets and high Mach-number flows; radiatively driven molecular clouds and nonlinear photoevaporation front dynamics; and photoionized plasmas relevant to accretion disks around compact objects, such as black holes and neutron stars.

Remington, B A; Drake, R P; Ryutov, D D

2004-12-10T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" 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

The upgraded rf system for the AGS and high intensity proton beams  

SciTech Connect

The AGS has been upgraded over the past three years to produce a record beam intensity of 6 {times} 10{sup 13} protons per pulse for the fixed-target physics program. The major elements of the upgrade are: the new 1.5 GeV Booster synchrotron, the main magnet power supply, a high frequency longitudinal dilution cavity, a feedback damper for transverse instabilities, a fast gamma transition jump system, and a new high-power rf system. The new rf system and its role in achieving the high intensity goal are the subjects of this report. The rf system is heavily beam loaded, with 7 Amps of rf current in the beam and a peak power of 0.75 MW delivered to the beam by ten cavities. As an example of the scale of beam loading, at one point in the acceleration cycle the cavities are operated at 1.5 kV/gap; whereas, were it not for the new power amplifiers, the beam-induced voltage on the cavities would be over 25 kV/gap. The upgraded rf system, comprising: new power amplifiers, wide band rf feedback, improved cavities, and new low-level beam control electronics, is described. Results of measurements with beam, which characterize the system`s performance, are presented. A typical high intensity acceleration cycle is described with emphasis on the key challenges of beam loading.

Brennan, J.M. [Brookhaven National Lab., Upton, NY (United States). AGS Dept.

1995-05-01T23:59:59.000Z

242

Development of High Average Power Lasers for the Photon Collider  

SciTech Connect

The laser and optics system for the photon collider seeks to minimize the required laser power by using an optical stacking cavity to recirculate the laser light. An enhancement of between 300 to 400 is desired. In order to achieve this the laser pulses which drive the cavity must precisely match the phase of the pulse circulating within the cavity. We report on simulations of the performance of a stacking cavity to various variations of the drive laser in order to specify the required tolerances of the laser system.

Gronberg, Jeff; /LLNL, Livermore; Stuart, Brent; /LLNL, Livermore; Seryi, Andrei; /SLAC

2012-07-05T23:59:59.000Z

243

Commissioning of the new high-intensity ultracold neutron source at the Paul Scherrer Institut  

E-Print Network (OSTI)

Commissioning of the new high-intensity ultracold neutron (UCN) source at the Paul Scherrer Institut (PSI) has started in 2009. The design goal of this new generation high intensity UCN source is to surpass by a factor of ~100 the current ultracold neutron densities available for fundamental physics research, with the greatest thrust coming from the search for a neutron electric dipole moment. The PSI UCN source is based on neutron production via proton induced lead spallation, followed by neutron thermalization in heavy water and neutron cooling in a solid deuterium crystal to cold and ultracold energies. A successful beam test with up to 2 mA proton beam on the spallation target was conducted recently. Most source components are installed, others being finally mounted. The installation is on the track for the first cool-down and UCN production in 2010.

Bernhard Lauss

2010-11-17T23:59:59.000Z

244

Surface area generation and droplet size control in solvent extraction systems utilizing high intensity electric fields  

DOE Patents (OSTI)

A method and system for solvent extraction where droplets are shattered by a high intensity electric field. These shattered droplets form a plurality of smaller droplets which have a greater combined surface area than the original droplet. Dispersion, coalescence and phase separation are accomplished in one vessel through the use of the single pulsing high intensity electric field. Electric field conditions are chosen so that simultaneous dispersion and coalescence are taking place in the emulsion formed in the electric field. The electric field creates a large amount of interfacial surface area for solvent extraction when the droplet is disintegrated and is capable of controlling droplet size and thus droplet stability. These operations take place in the presence of a counter current flow of the continuous phase.

Scott, Timothy C. (Knoxville, TN); Wham, Robert M. (Oak Ridge, TN)

1988-01-01T23:59:59.000Z

245

Calculation of synchrotron radiation from high intensity electron beam at eRHIC  

Science Conference Proceedings (OSTI)

The Electron-Relativistic Heavy Ion Collider (eRHIC) at Brookhaven National Lab is an upgrade project for the existing RHIC. A 30 GeV energy recovery linac (ERL) will provide a high charge and high quality electron beam to collide with proton and ion beams. This will improve the luminosity by at least 2 orders of magnitude. The synchrotron radiation (SR) from the bending magnets and strong quadrupoles for such an intense beam could be penetrating the vacuum chamber and producing hazards to electronic devices and undesired background for detectors. In this paper, we calculate the SR spectral intensity, power density distributions and heat load on the chamber wall. We suggest the wall thickness required to stop the SR and estimate spectral characteristics of the residual and scattered background radiation outside the chamber.

Jing Y.; Chubar, O.; Litvinenko, V.

2012-05-20T23:59:59.000Z

246

Laser Spark Plug Development  

Science Conference Proceedings (OSTI)

To meet the ignition system needs of large bore high pressure lean burn natural gas engines a laser diode side pumped passively Q-switched laser igniter was designed and tested. The laser was designed to produce the optical intensities needed to initiate ignition in a lean burn high brake mean effective pressure (BMEP) engine. The experimentation explored a variety of optical and electrical input parameters that when combined produced a robust spark in air. The results show peak power levels exceeding 2 MW and peak focal intensities above 400 GW/cm2. Future research avenues and current progress with the initial prototype are presented and discussed.

McIntyre, D.L.; Richardson, S.W.; Woodruff, S.D.; McMillian, M.H.; Guutam, M. (West Virginia Univ., Morgantown, WV)

2007-04-01T23:59:59.000Z

247

Development of a high intensity EBIT for basic and applied science/011  

Science Conference Proceedings (OSTI)

The electron-beam ion trap (EBIT) is a device for producing and studying cold, very highly charged ions of any element, up to a fully ionized U{sup 92+}. These highly charged ions occur in hot plasmas and therefore play important roles in nuclear weapons, controlled fusion, and astrophysical phenomena. The remarkable interaction of these ions with surfaces may lead to technological applications. The highly charged ions can either be studied inside the EBIT itself with measurements of their x-ray emission spectra, or the ions can be extracted from the EBIT in order to study their interaction with solid material. Both types of measurements are being pursued vigorously with the two existing low-intensity EBITs at LLNL and with similar EBITs that have been built at six other laboratories around the world since the EBIT was first developed at LLNL 10 years ago. However, all existing EBITs have approximately the same intensity as the original LLNL EBIT; that is, they all produce about the same number of very-highly-charged ions (roughly 2 x 10{sup 6} per second) and the same number of x-ray photons (roughly 10{sup 7} per second). The goal of the High-Intensity-EBIT project is to increase the x-ray emission per centimeter of length along the electron beam by a factor of 100 and to increase the ion output by a factor of 1000. This dramatic increase in intensity will enable the next generation of basic and applied experimental research in the structure of highly charged ions. For example, the precision of EBIT x-ray measurements of atomic energy levels- which is now limited by count rate-can be improved by an order of magnitude, and new applications in surface science, nanotechnology, and microscopy will be possible with the expected intense ion beams. When the high ion output is combined with the demonstrated low emittance of EBIT ions, we will have a high-brightness source of highly charged ions that can be focused to submicrometer spots. One example of a measurement that will benefit from increased x-ray intensity is our study of the binding energy of high-Z heliumlike ions. The small ``two-electron`` contribution to this binding energy is a fundamental aspect of atomic structure. It arises from the small forces that the two electrons exert on each other in the presence of the much larger force from the atomic nucleus. Our existing EBIT measurements are sensitive to the so-called ``second order`` contribution to the two-electron binding energy, but with the High-Intensity EBIT we can probe an even more subtle effect: the screening by one electron of the quantum electrodynamic (QED) energy contribution from the other electron.

Marrs, R.E., LLNL

1998-02-05T23:59:59.000Z

248

650 mm long liquid hydrogen target for use in a high intensity electron beam  

DOE Green Energy (OSTI)

This paper describes a 650 mm long liquid hydrogen targetr constructed for use in the high intensity electron beam at the Stanford Linear Accelerator Center (SLAC). The main design problem was to construct a target that would permit the heat deposited by the electron beam to be removed rapidly without boiling the hydrogen so as to maintain constant target density for optimum data taking. Design requirements, cosntruction details and operating experience are discussed.

Mark, J.W.

1984-02-01T23:59:59.000Z

249

650 mm long liquid hydrogen target for use in a high intensity electron beam  

DOE Green Energy (OSTI)

This paper describes a 650 mm long liquid hydrogen target constructed for use in the high intensity electron beam at the Stanford Linear Accelerator Center. The main design problem was to construct a target that would permit the heat deposited by the electron beam to be removed rapidly without boiling the hydrogen so as to maintain constant target density for optimum data taking. Design requirements, construction details and operating experience are discussed.

Mark, J.W.

1983-07-01T23:59:59.000Z

250

Laser Seeding Yields High-Power Coherent Terahertz Radiation  

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

is generated in electron storage rings when femtosecond lasers are used to carve out ultrafast x-ray pulses by femtoslicing (see "Tailored Terahertz Pulses from a Laser-Modulated...

251

High-efficiency free-electron laser results  

Science Conference Proceedings (OSTI)

Results obtained with a tapered-wiggler free-electron laser demonstrate the concepts proposed by Morton for enhanced efficiency and show deceleration of electrons by as much as 7%, and extraction of more than 3% of the total electron-beam energy as laser energy when the laser is operated as an amplifier. The experiment is presently being reconfigured to examine its performance as a laser oscillator.

Boyer, K.; Baru, C.A.; Newnam, B.E.; Stein, W.E.; Warren, R.W.; Winston, J.G.; Young, L.M.

1983-01-01T23:59:59.000Z

252

High-power copper vapour lasers and applications  

Science Conference Proceedings (OSTI)

Expanded applications of copper vapor lasers has prompted increased demand for higher power and better beam quality. This paper reports recent progress in laser power scaling, MOPA operation, beam quality improvement, and applications in precision laser machining. Issues such as gas heating, radial delay, discharge instability, and window heating will also be discussed.

Chang, J.J.; Warner, B.E.; Boley, C.D.; Dragon, E.P.

1995-08-01T23:59:59.000Z

253

High intensity discharge 400-watt sodium ballast. Phase I. Final report  

SciTech Connect

The results of a research and development program directed toward design, test, and evaluation of energy efficient High Intensity Discharge (HID) Solid State 400-Watt Ballast lighting system are reported. Phase I of the project which was designed to modify the existing Datapower ballast to LBL configuration, measure performance characteristics, and compare efficiency with a core/coil ballast including energy loss analysis is covered. In addition, Datapower was tasked to build six (6) prototype 400-Watt High Pressure Sodium Ballasts for verification tests by an independent test facility and follow-on performance and life tests at LBL.

Felper, G.

1980-06-01T23:59:59.000Z

254

Low-Cost, High-Power Laser for Analytical and Other ...  

Search PNNL. PNNL Home; About; Research; Publications; Jobs; News; Contacts; Low-Cost, High-Power Laser for Analytical and Other Applications. ...

255

Gain media edge treatment to suppress amplified spontaneous emission in a high power laser  

DOE Patents (OSTI)

A novel method and apparatus for suppressing ASE and parasitic oscillation modes in a high average power laser is introduced. By roughening one or more peripheral edges of a solid-state crystal or ceramic laser gain media and by bonding such edges using a substantially high index bonding elastomer or epoxy to a predetermined electromagnetic absorbing arranged adjacent to the entire outer surface of the peripheral edges of the roughened laser gain media, ASE and parasitic oscillation modes can be effectively suppressed.

Hackel, Lloyd A. (Livermore, CA); Soules, Thomas F. (Livermore, CA); Fochs, Scott N. (Livermore, CA); Rotter, Mark D. (San Ramon, CA); Letts, Stephan A. (San Ramon, CA)

2008-12-09T23:59:59.000Z

256

Production of Sparks Via High Quality Laser Pulses Transmitted ...  

Fiber optic technology allows the laser to be located away from the extreme conditions inside the ... Fiber optic system allows diagnostic light to return for analysis.

257

High repetition rate fiber and integrated waveguide femtosecond lasers  

E-Print Network (OSTI)

Femtosecond lasers and the development of frequency combs have revolutionized multiple fields like metrology, spectroscopy, medical diagnostics and optical communications. However, to enable wider adoption of the technology ...

Sander, Michelle Y. (Michelle Yen-Ling)

2012-01-01T23:59:59.000Z

258

Nonperturbative Vacuum-Polarization Effects in Proton-Laser Collisions  

Science Conference Proceedings (OSTI)

In the collision of a high-energy proton beam and a strong laser field, merging of laser photons can occur due to the polarization of vacuum. The probability of photon merging is calculated by exactly accounting for the laser field which involves a highly nonperturbative dependence on the laser intensity and frequency. It is shown that the nonperturbative vacuum-polarization effects can be experimentally measured by combining the next generation of tabletop petawatt lasers with proton accelerators presently available.

Di Piazza, A.; Hatsagortsyan, K. Z.; Keitel, C. H. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

2008-01-11T23:59:59.000Z

259

High-intensity ion sources for accelerators with emphasis on H-beam formation and transport  

SciTech Connect

This paper lays out the fundamental working principles of a variety of high-current ion sources for accelerators in a tutorial manner, and gives examples of specific source types such as d. c. discharge- and rf-driven multicusp sources. Penning-type and ECR-based sources while discussing those principles, pointing out general performance limits as well as the performance parameters of specific sources. Laser-based, two-chamber-. and surface-ionization sources are briefly mentioned. Main aspects of this review are particle feed. ionization mechanism, beam formation and beam transport. Issues seen with beam formation and low-energy transport of negative hydrogen-ion beams are treated in detail.

Keller, Roderich [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

260

A Class Of Generalized Kapchinskij-Vladimirskij Solutions And Associated Envelope Equations For High-intensity Charged Particle Beams  

SciTech Connect

A class of generalized Kapchinskij-Vladimirskij solutions of the nonlinear Vlasov-Maxwell equations and the associated envelope equations for high-intensity beams in a periodic lattice is derived. It includes the classical Kapchinskij-Vladimirskij solution as a special case. For a given lattice, the distribution functions and the envelope equations are specified by eight free parameters. The class of solutions derived captures a wider range of dynamical envelope behavior for high-intensity beams, and thus provides a new theoretical tool to investigate the dynamics of high-intensity beams.

Hong Qin and Ronald C. Davidson

2012-04-25T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" 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.


261

Lasers and Optoelectronic Components Used with Lasers  

Science Conference Proceedings (OSTI)

... example, beam profile and relative intensity noise ... for the laser wavelengths and energies for which ... The laser power and energy measurements are ...

2013-06-28T23:59:59.000Z

262

Nonlinear laser energy depletion in laser-plasma accelerators  

E-Print Network (OSTI)

Nonlinear laser energydepletion in laser-plasma accelerators ? B. A. Shadwick,of intense, short-pulse lasers via excitation of plasma

Shadwick, B.A.

2009-01-01T23:59:59.000Z

263

Formation of ordered one-dimensional microstructures of dislocations in near-surface layer of semiconductor, under laser radiation with microstructured distribution of intensity  

Science Conference Proceedings (OSTI)

The paper presents the results of investigation the process of formation of the ordered microstructures of dislocations in the near-surface layer a single-crystal plate of silicon under the action of pulsed laser radiation with microstructured distribution intensity. It has been found that generation of the ordered one-dimensional microstructures of dislocations takes place. The period of these ordered microstructures is d{approx_equal}3 divide 4 {mu}m. A combination of one-dimensional structures of dislocations produces ordered two-dimensional structure of dislocations.

Banishev, A. F.; Banishev, A. A. [Institute on Laser and Information Technologies RAS (ILIT RAS), Svyatoozerskaya Str.1, 140700 Shatura, Moscow Region (Russian Federation)

2012-03-15T23:59:59.000Z

264

High-Intensity and High-Density Charge-Exchange Injection Studies into the CERN PS Booster at Intermediate Energies  

E-Print Network (OSTI)

For the high brilliance LHC ultimate beam and the high intensity CNGS beam, single batch injections into the CERN Proton Synchrotron (PS) will be used to increase the overall machine intensity compared with the present double batch injections. Charge-exchange injection into the PS Booster with a new linac at intermediate energies is thus examined. A key parameter to consider is the energy dependence of beam incoherent tune shifts at injection. Increasing the linac energy from the present 50 MeV to 160 MeV should yield a safer tune shift. For each PS Booster ring, a charge-exchange injection scheme is envisaged inside a proper straight section, redesigned with new bends to make a local bump and using the existing fast bump magnets for horizontal phase-space painting. ACCSIM simulations for charge-exchange injection at 160 MeV have been investigated for both LHC and CNGS beams. After optimizing the parameters that are used for the space charge tracking routines, the results of the simulations agree well with ex...

Martini, M

2004-01-01T23:59:59.000Z

265

Attaining and using extremely high intensities of solar energy with non-imaging concentrators  

SciTech Connect

Using the principles and techniques of non-imaging optics, solar concentrations that approach the theoretical maximum can be achieved. In this paper, the authors review recent progress in attaining, measuring, and using such ultrahigh solar fluxes. In particular, they review the design principles for optimized two-stage concentrators and solar furnaces and discuss the characteristics and properties of a variety of non-imaging secondaries which have been employed. These include Compound Parabolic Concentrators (CPC) type secondaries, Dielectric Totally Internally Reflecting Concentrators (DTIRC), and flow-line or {open_quotes}trumpet{close_quotes} concentrators. The usual design is a configuration where {phi}, the rim angle of the primary, is small, that is, corresponding to a system with a relatively large focal length to diameter (F/D) ratio. All three types of secondary are characterized by a design acceptance angle {phi}{sub a} which must be greater than or equal to {phi}. The design parameters and trade-offs for each of these systems including strategies for choice of particular secondary and degree of truncation, are presented. The authors review the calorimetric techniques used to measure these high intensities and describe a newly developed technique for {open_quotes}extracting{close_quotes} light from inside a high index medium. Finally they review a number of potential applications for highly concentrated solar energy and the current status of the associated technology. By making possible new and unique applications for intense solar flux, these techniques have opened a whole new frontier for research and development of potential economic uses of solar energy. 63 refs., 34 figs., 3 tabs.

Jenkins, D.; O`Gallagher, J.; Winston, R.

1997-12-31T23:59:59.000Z

266

Segmented lasing tube for high temperature laser assembly  

DOE Patents (OSTI)

A high temperature laser assembly capable of withstanding operating temperatures in excess of 1500.degree. C. is described comprising a segmented cylindrical ceramic lasing tube having a plurality of cylindrical ceramic lasing tube segments of the same inner and outer diameters non-rigidly joined together in axial alignment; insulation of uniform thickness surround the walls of the ceramic lasing tube; a ceramic casing, preferably of quartz, surrounding the insulation; and a fluid cooled metal jacket surrounds the ceramic casing. In a preferred embodiment, the inner surface of each of the ceramic lasing tube segments are provided with a pair of oppositely spaced grooves in the wall thereof parallel to the center axis of the segmented cylindrical ceramic lasing tube, and both of the grooves and the center axis of the segmented cylindrical ceramic lasing tube lie in a common plane, with the grooves in each ceramic lasing tube segment in circumferential alignment with the grooves in the adjoining ceramic lasing tube segments; and one or more ceramic plates, all lying in a common plane to one another and with the central axis of the segmented ceramic lasing tube, are received in the grooves to provide additional wall area in the segmented ceramic lasing tube for collision and return to ground state of metastable metal atoms within the segmented ceramic lasing tube.

Sawicki, Richard H. (Danville, CA); Alger, Terry W. (Tracy, CA); Finucane, Raymond G. (Pleasanton, CA); Hall, Jerome P. (Livermore, CA)

1996-01-01T23:59:59.000Z

267

Absolute intensity calibration of the Wendelstein 7-X high efficiency extreme ultraviolet overview spectrometer system  

Science Conference Proceedings (OSTI)

The new high effiency extreme ultraviolet overview spectrometer (HEXOS) system for the stellarator Wendelstein 7-X is now mounted for testing and adjustment at the tokamak experiment for technology oriented research (TEXTOR). One part of the testing phase was the intensity calibration of the two double spectrometers which in total cover a spectral range from 2.5 to 160.0 nm with overlap. This work presents the current intensity calibration curves for HEXOS and describes the method of calibration. The calibration was implemented with calibrated lines of a hollow cathode light source and the branching ratio technique. The hollow cathode light source provides calibrated lines from 16 up to 147 nm. We could extend the calibrated region in the spectrometers down to 2.8 nm by using the branching line pairs emitted by an uncalibrated pinch extreme ultraviolet light source as well as emission lines from boron and carbon in TEXTOR plasmas. In total HEXOS is calibrated from 2.8 up to 147 nm, which covers most of the observable wavelength region. The approximate density of carbon in the range of the minor radius from 18 to 35 cm in a TEXTOR plasma determined by simulating calibrated vacuum ultraviolet emission lines with a transport code was 5.5x10{sup 17} m{sup -3} which corresponds to a local carbon concentration of 2%.

Greiche, Albert; Biel, Wolfgang; Marchuk, Oleksandr [Institut fuer Energieforschung-Plasmaphysik, Forschungszentrum Juelich GmbH, EURATOM Association, Trilateral Euregio Cluster, D-52425 Juelich (Germany); Burhenn, Rainer [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-17491 Greifswald (Germany)

2008-09-15T23:59:59.000Z

268

Influence of Intense Beam in High Pressure Hydrogen Gas Filled RF Cavities  

DOE Green Energy (OSTI)

The influence of an intense beam in a high-pressure gas filled RF cavity has been measured by using a 400 MeV proton beam in the Mucool Test Area at Fermilab. The ionization process generates dense plasma in the cavity and the resultant power loss to the plasma is determined by measuring the cavity voltage on a sampling oscilloscope. The energy loss has been observed with various peak RF field gradients (E), gas pressures (p), and beam intensities in nitrogen and hydrogen gases. Observed RF energy dissipation in single electron (dw) in N{sub 2} and H{sub 2} gases was 2 10{sup -17} and 3 10{sup -17} Joules/RF cycle at E/p = 8 V/cm/Torr, respectively. More detailed dw measurement have been done in H{sub 2} gas at three different gas pressures. There is a clear discrepancy between the observed dw and analytical one. The discrepancy may be due to the gas density effect that has already been observed in various experiments.

Yonehara, K.; Chung, M.; Collura, M.G.; Jana, M.R.; Leonova, M.; Moretti, A.; Popovic, M.; Schwarz, T.; Tollestrup, A.; /Fermilab; Johnson, R.P.; Franagan, G.; /Muons, Inc. /IIT

2012-05-01T23:59:59.000Z

269

A Lightweight, High-performance I/O Management Package for Data-intensive Computing  

Science Conference Proceedings (OSTI)

Our group has been working with ANL collaborators on the topic â??bridging the gap between parallel file system and local file systemâ?ť during the course of this project period. We visited Argonne National Lab -- Dr. Robert Rossâ??s group for one week in the past summer 2007. We looked over our current project progress and planned the activities for the incoming years 2008-09. The PI met Dr. Robert Ross several times such as HEC FSIO workshop 08, SCâ??08 and SCâ??10. We explored the opportunities to develop a production system by leveraging our current prototype to (SOGP+PVFS) a new PVFS version. We delivered SOGP+PVFS codes to ANL PVFS2 group in 2008.We also talked about exploring a potential project on developing new parallel programming models and runtime systems for data-intensive scalable computing (DISC). The methodology is to evolve MPI towards DISC by incorporating some functions of Google MapReduce parallel programming model. More recently, we are together exploring how to leverage existing works to perform (1) coordination/aggregation of local I/O operations prior to movement over the WAN, (2) efficient bulk data movement over the WAN, (3) latency hiding techniques for latency-intensive operations. Since 2009, we start applying Hadoop/MapReduce to some HEC applications with LANL scientists John Bent and Salman Habib. Another on-going work is to improve checkpoint performance at I/O forwarding Layer for the Road Runner super computer with James Nuetz and Gary Gridder at LANL. Two senior undergraduates from our research group did summer internships about high-performance file and storage system projects in LANL since 2008 for consecutive three years. Both of them are now pursuing Ph.D. degree in our group and will be 4th year in the PhD program in Fall 2011 and go to LANL to advance two above-mentioned works during this winter break. Since 2009, we have been collaborating with several computer scientists (Gary Grider, John bent, Parks Fields, James Nunez, Hsing-Bung Chen, etc) from HPC5 and James Ahrens from Advanced Computing Laboratory in Los Alamos National Laboratory. We hold a weekly conference and/or video meeting on advancing works at two fronts: the hardware/software infrastructure of building large-scale data intensive cluster and research publications. Our group members assist in constructing several onsite LANL data intensive clusters. Two parties have been developing software codes and research papers together using both sidesâ?? resources.

Wang, Jun

2011-06-22T23:59:59.000Z

270

Analysis of Intense Poleward Water Vapor Transports into High Latitudes of Western North America  

Science Conference Proceedings (OSTI)

Significant cool season precipitation along the western coast of North America is often associated with intense water vapor transport (IWVT) from the Pacific Ocean during favorable synoptic-scale flow regimes. These relatively narrow and intense ...

Alain Roberge; John R. Gyakum; Eyad H. Atallah

2009-12-01T23:59:59.000Z

271

The National Ignition Facility National Ignition Campaign Short Pulse Lasers High-Average-Power Laser  

E-Print Network (OSTI)

-Average-Power Laser NIF-1005-11471 07BEW/dj P9765 Agenda #12;P9516NIF-0805-11197 01EIM/dj Stockpile Stewardship #12;P9504NIF-0404-08345r2 27EIM/ld Basic Science and Cosmology #12;NIF-0702-05346rIFSA Fusion Energy Campaign and point design NIF-0305-10564 23MLS/cld P8719 The NIF Laser User Optics Physics Operations

272

Production of Sparks via High-Quality Laser Pulses Through ...  

Fiber optic technology allows the laser to be located away from the ... The system allows light produced by the combus-tion to return from the cylinder for analysis.

273

Characterization and analysis of highly diagonal Terahertz Quantum Cascade Lasers  

E-Print Network (OSTI)

The as yet unattained milestone of room-temperature operation is essential for establishing Terahertz Quantum Cascade Lasers (THz QCLs) as practical sources of THz radiation. Temperature performance is hypothesized to be ...

Chan, Chun Wang Ivan

2010-01-01T23:59:59.000Z

274

Industrial Application of High Combustion Intensity Systems and Energy Conservation Implications  

E-Print Network (OSTI)

In the past decade industrial combustion technology has been advanced through adaptations of the equipment operating with dramatically reduced excess air requirements and use of air preheat techniques. The importance of operating industrial combustion equipment at stoichiometric conditions is emphasized. The calculated fuel savings resulting from elimination of excess air and use of heat recovery air preheat are reviewed. Design parameters for the aerodynamic design and control of the combustion process are quantified for vortex stabilized systems. Design analyses of the fuel injectors used with gaseous, liquid and pulverized coal fuels are also presented. The resulting high intensity combustion systems evolved are illustrated with photographs of flames in actual installations and during equipment development testing. Attention to detail in equipment manufacture and proper field adjustment of combustion equipment is essential in achieving the dramatic fuel savings that are possible.

Williams, F. D. M.; Anderson, L. E.

1982-01-01T23:59:59.000Z

275

High-Power Laser Pulse Recirculation for Inverse Compton Scattering-Produced Gamma-Rays  

Science Conference Proceedings (OSTI)

Inverse Compton scattering of high-power laser pulses on relativistic electron bunches represents an attractive method for high-brightness, quasi-monoenergetic {gamma}-ray production. The efficiency of {gamma}-ray generation via inverse Compton scattering is severely constrained by the small Thomson scattering cross section. Furthermore, repetition rates of high-energy short-pulse lasers are poorly matched with those available from electron accelerators, resulting in low repetition rates for generated {gamma}-rays. Laser recirculation has been proposed as a method to address those limitations, but has been limited to only small pulse energies and peak powers. Here we propose and experimentally demonstrate an alternative method for laser pulse recirculation that is uniquely capable of recirculating short pulses with energies exceeding 1 J. Inverse Compton scattering of recirculated Joule-level laser pulses has a potential to produce unprecedented peak and average {gamma}-ray brightness in the next generation of sources.

Jovanovic, I; Shverdin, M; Gibson, D; Brown, C

2007-04-17T23:59:59.000Z

276

Application of high powered lasers to drilling and completing deep walls.  

SciTech Connect

High powered laser rock drilling was studied as a revolutionary method for drilling and completing deep gas and oil wells. The objectives of this 2002 to 2003 fiscal year research were to study the concept that large diameter holes can be created by multiple overlapping small beam spots, to determine the ability of lasers to drill rock submerged to some depth in water, to demonstrate the possibilities of lasers for perforating application, and to determine the wavelength effects on rock removal. Laser technology applied to well drilling and completion operations is attractive because it has the potential to reduce drilling time, create a ceramic lining that may eliminate the need for steel casing, provide additional monitor-on-drilling laser sensors and improve well performance through improved perforation. The results from this research will help engineering design on a laser-based well drilling system.

Reed, C. B.; Xu, Z.; Parker, R. A.; Gahan, B. C.; Batarseh, S.; Graves, R. M.; Figueroa, H.; Deeg, W.

2003-07-30T23:59:59.000Z

277

Method for optical pumping of thin laser media at high average power  

DOE Patents (OSTI)

A thin, planar laser material is bonded to a light guide of an index-matched material forming a composite disk. Diode array or other pump light is introduced into the composite disk through the edges of the disk. Pump light trapped within the composite disk depletes as it multi-passes the laser medium before reaching an opposing edge of the disk. The resulting compound optical structure efficiently delivers concentrated pump light and to a laser medium of minimum thickness. The external face of the laser medium is used for cooling. A high performance cooler attached to the external face of the laser medium rejects heat. Laser beam extraction is parallel to the heat flux to minimize optical distortions.

Zapata, Luis E. (Livermore, CA); Beach, Raymond J. (Livermore, CA); Honea, Eric C. (Sunol, CA); Payne, Stephen A. (Castro Valley, CA)

2004-07-13T23:59:59.000Z

278

Optimized laser pulse profile for efficient radiation pressure acceleration of ions  

SciTech Connect

The radiation pressure acceleration regime of laser ion acceleration requires high intensity laser pulses to function efficiently. Moreover the foil should be opaque for incident radiation during the interaction to ensure maximum momentum transfer from the pulse to the foil, which requires proper matching of the target to the laser pulse. However, in the ultrarela-tivistic regime, this leads to large acceleration distances, over which the high laser intensity for a Gaussian laser pulse must be maintained. It is shown that proper tailoring of the laser pulse profile can significantly reduce the acceleration distance, leading to a compact laser ion accelerator, requiring less energy to operate.

Bulanov, S. S.; Schroeder, C. B.; Esarey, E.; Leemans, W. P. [University of California, Berkeley, California 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States) and University of California, Berkeley, California 94720 (United States)

2012-12-21T23:59:59.000Z

279

Optimized laser pulse profile for efficient radiation pressure acceleration of ions  

Science Conference Proceedings (OSTI)

The radiation pressure acceleration regime of laser ion acceleration requires high intensity laser pulses to function efficiently. Moreover, the foil should be opaque for incident radiation during the interaction to ensure maximum momentum transfer from the pulse to the foil, which requires proper matching of the target to the laser pulse. However, in the ultrarelativistic regime, this leads to large acceleration distances, over which the high laser intensity for a Gaussian laser pulse must be maintained. It is shown that proper tailoring of the laser pulse profile can significantly reduce the acceleration distance, leading to a compact laser ion accelerator, requiring less energy to operate.

Bulanov, S. S. [University of California, Berkeley, California 94720 (United States); Schroeder, C. B.; Esarey, E. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Leemans, W. P. [University of California, Berkeley, California 94720 (United States); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

2012-09-15T23:59:59.000Z

280

Fabrication of Gold-Platinum Nanoalloy by High-Intensity Laser ...  

Science Conference Proceedings (OSTI)

After irradiation, absorption peak arise from surface plasmon resonance of gold nanoparticles ... Engineering Shapes in Nanotechnology: Helicity on Demand.

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281

High energy bursts from a solid state laser operated in the heat capacity limited regime  

DOE Patents (OSTI)

High energy bursts are produced from a solid state laser operated in a heat capacity limited regime. Instead of cooling the laser, the active medium is thermally well isolated. As a result, the active medium will heat up until it reaches some maximum acceptable temperature. The waste heat is stored in the active medium itself. Therefore, the amount of energy the laser can put out during operation is proportional to its mass, the heat capacity of the active medium, and the temperature difference over which it is being operated. The high energy burst capacity of a heat capacity operated solid state laser, together with the absence of a heavy, power consuming steady state cooling system for the active medium, will make a variety of applications possible. Alternately, cooling takes place during a separate sequence when the laser is not operating. Industrial applications include new material working processes.

Albrecht, Georg (Livermore, CA); George, E. Victor (Livermore, CA); Krupke, William F. (Pleasanton, CA); Sooy, Walter (Pleasanton, CA); Sutton, Steven B. (Manteca, CA)

1996-01-01T23:59:59.000Z

282

High energy bursts from a solid state laser operated in the heat capacity limited regime  

DOE Patents (OSTI)

High energy bursts are produced from a solid state laser operated in a heat capacity limited regime. Instead of cooling the laser, the active medium is thermally well isolated. As a result, the active medium will heat up until it reaches some maximum acceptable temperature. The waste heat is stored in the active medium itself. Therefore, the amount of energy the laser can put out during operation is proportional to its mass, the heat capacity of the active medium, and the temperature difference over which it is being operated. The high energy burst capacity of a heat capacity operated solid state laser, together with the absence of a heavy, power consuming steady state cooling system for the active medium, will make a variety of applications possible. Alternately, cooling takes place during a separate sequence when the laser is not operating. Industrial applications include new material working processes. 5 figs.

Albrecht, G.; George, E.V.; Krupke, W.F.; Sooy, W.; Sutton, S.B.

1996-06-11T23:59:59.000Z

283

High-intensity-discharger 400-W sodium ballast. Phase II. Final report  

SciTech Connect

A research and development program directed toward design, test, and evaluation of an energy efficient High Intensity Discharge (HID) Solid-State 400 Watt Ballast lighting system was undertaken. Under Phase I of the project, the existing ballast was modified, performance characteristics were measured, efficiency was compared with a core/coil ballast including energy loss analysis. Six (6) prototype 400 W High Pressure Sodium Ballasts were built, for verification tests by an independent test facility prior to follow-on performance and life tests. This report covers Phase II of the project which was designed to make test data comparisons on results received from the independent test laboratory, determine methods to increase ballast efficiency, determine the importance of power factors, conduct bulb life tests, perform specification review, performance versus cost analysis, investigate the ballast to determine compliance with new FCC requirement, and determine a line transient specification in respect to solid state ballasting. In addition, Phase II required reliability testing, a manufacturing test plan, a marketing study for solid-state ballast, and the manufacture and delivery of fifteen (15) demonstration ballast units to LBL. These requirements are discussed.

Felper, G.

1981-10-01T23:59:59.000Z

284

High efficiency 2 micrometer laser utilizing wing-pumped Tm{sup 3+} and a laser diode array end-pumping architecture  

DOE Patents (OSTI)

Wing pumping a Tm{sup 3+} doped, end pumped solid state laser generates 2 {micro}m laser radiation at high average powers with high efficiency. Using laser diode arrays to end-pump the laser rod or slab in the wing of the Tm{sup 3+} absorption band near 785 nm results in 2-for-1 quantum efficiency in Tm{sup 3+} because high Tm{sup 3+} concentrations can be used. Wing pumping allows the thermal power generated in the rod or slab to be distributed over a large enough volume to make thermal management practical in the laser gain medium even at high average power operation. The approach is applicable to CW, Q-switched, and rep-pulsed free-laser operation. 7 figs.

Beach, R.J.

1997-11-18T23:59:59.000Z

285

High efficiency 2 micrometer laser utilizing wing-pumped Tm.sup.3+ and a laser diode array end-pumping architecture  

DOE Patents (OSTI)

Wing pumping a Tm.sup.3+ doped, end pumped solid state laser generates 2 .mu.m laser radiation at high average powers with high efficiency. Using laser diode arrays to end-pump the laser rod or slab in the wing of the Tm.sup.3+ absorption band near 785 nm results in 2-for-1 quantum efficiency in Tm.sup.3+ because high Tm.sup.3+ concentrations can be used. Wing pumping allows the thermal power generated in the rod or slab to be distributed over a large enough volume to make thermal management practical in the laser gain medium even at high average power operation. The approach is applicable to CW, Q-switched, and rep-pulsed free-laser operation.

Beach, Raymond J. (Livermore, CA)

1997-01-01T23:59:59.000Z

286

D&D Toolbox Robotic Deployment of High Resolution Laser Imaging for  

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

D&D Toolbox Robotic Deployment of High Resolution Laser Imaging for D&D Toolbox Robotic Deployment of High Resolution Laser Imaging for Characterization D&D Toolbox Robotic Deployment of High Resolution Laser Imaging for Characterization The characterization of complex and/or hazardous facilities for the purposes of planning D&D projects can be excessively time consuming and present unacceptable hazards for personnel who enter or access the facility. D&D Toolbox Robotic Deployment of High Resolution Laser Imaging for Characterization More Documents & Publications D&D Toolbox Project - Technology Demonstration of Fixatives Applied to Hot Cell Facilities via Remote Sprayer Platforms Above on the left is K-25, at Oak Ridge before and after the 844,000 sq-ft demolition. In addition, on the right: K Cooling Tower at Savannah River Site demolition.

287

D&D Toolbox Robotic Deployment of High Resolution Laser Imaging for  

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

Robotic Deployment of High Resolution Laser Imaging for Robotic Deployment of High Resolution Laser Imaging for Characterization D&D Toolbox Robotic Deployment of High Resolution Laser Imaging for Characterization The characterization of complex and/or hazardous facilities for the purposes of planning D&D projects can be excessively time consuming and present unacceptable hazards for personnel who enter or access the facility. D&D Toolbox Robotic Deployment of High Resolution Laser Imaging for Characterization More Documents & Publications Above on the left is K-25, at Oak Ridge before and after the 844,000 sq-ft demolition. In addition, on the right: K Cooling Tower at Savannah River Site demolition. Deactivation & Decommissioning (D&D) Program Map DOE EM Project Experience & Lessons Learned for In Situ Decommissioning

288

High repetition rate mode-locked erbium-doped fiber lasers with complete electric field control  

E-Print Network (OSTI)

Recent advances in fully-stabilized mode-locked laser systems are enabling many applications, including optical arbitrary waveform generation (OAWG). In this thesis work, we describe the development of high repetition-rate ...

Sickler, Jason William, 1978-

2008-01-01T23:59:59.000Z

289

Climate Change: Anticipated Effects on High-Energy Laser Weapon Systems in Maritime Environments  

Science Conference Proceedings (OSTI)

This study quantifies the potential impacts on ship-defense high-energy-laser (HEL) performance due to atmospheric effects in the marine boundary layer driven by recent observations and analysis of worldwide sea surface temperatures (SSTs). The ...

Steven T. Fiorino; Robb M. Randall; Richard J. Bartell; Adam D. Downs; Peter C. Chu; C. W. Fan

2011-01-01T23:59:59.000Z

290

Improved performance of high average power semiconductor arrays for applications in diode pumped solid state lasers  

Science Conference Proceedings (OSTI)

The average power performance capability of semiconductor diode laser arrays has improved dramatically over the past several years. These performance improvements, combined with cost reductions pursued by LLNL and others in the fabrication and packaging of diode lasers, have continued to reduce the price per average watt of laser diode radiation. Presently, we are at the point where the manufacturers of commercial high average power solid state laser systems used in material processing applications can now seriously consider the replacement of their flashlamp pumps with laser diode pump sources. Additionally, a low cost technique developed and demonstrated at LLNL for optically conditioning the output radiation of diode laser arrays has enabled a new and scalable average power diode-end-pumping architecture that can be simply implemented in diode pumped solid state laser systems (DPSSL`s). This development allows the high average power DPSSL designer to look beyond the Nd ion for the first time. Along with high average power DPSSL`s which are appropriate for material processing applications, low and intermediate average power DPSSL`s are now realizable at low enough costs to be attractive for use in many medical, electronic, and lithographic applications.

Beach, R.; Emanuel, M.; Benett, W.; Freitas, B.; Ciarlo, D.; Carlson, N.; Sutton, S.; Skidmore, J.; Solarz, R.

1994-01-01T23:59:59.000Z

291

Collective Focusing of Intense Ion Beam Pulses for High-energy Density Physics Applications  

SciTech Connect

The collective focusing concept in which a weak magnetic lens provides strong focusing of an intense ion beam pulse carrying a neutralizing electron background is investigated by making use of advanced particle-in-cell simulations and reduced analytical models. The original analysis by Robertson Phys. Rev. Lett. 48, 149 (1982) is extended to the parameter regimes of particular importance for several high-energy density physics applications. The present paper investigates (1) the effects of non-neutral collective focusing in a moderately strong magnetic field; (2) the diamagnetic effects leading to suppression of the applied magnetic field due to the presence of the beam pulse; and (3) the influence of a finite-radius conducting wall surrounding the beam cross-section on beam neutralization. In addition, it is demonstrated that the use of the collective focusing lens can significantly simplify the technical realization of the final focusing of ion beam pulses in the Neutralized Drift Compression Experiment-I (NDCX-I) , and the conceptual designs of possible experiments on NDCX-I are investigated by making use of advanced numerical simulations. 2011 American Institute of Physics

Mikhail A. Dorf, Igor D. Kaganovich, Edward A. Startsev and Ronald C. Davidson

2011-04-27T23:59:59.000Z

292

Ionization of one- and three-dimensionally-oriented asymmetric-top molecules by intense circularly polarized femtosecond laser pulses  

SciTech Connect

We present a combined experimental and theoretical study on strong-field ionization of a three-dimensionally-oriented asymmetric top molecule, benzonitrile (C{sub 7}H{sub 5}N), by circularly polarized, nonresonant femtosecond laser pulses. Prior to the interaction with the strong field, the molecules are quantum-state selected using a deflector and three-dimensionally (3D) aligned and oriented adiabatically using an elliptically polarized laser pulse in combination with a static electric field. A characteristic splitting in the molecular frame photoelectron momentum distribution reveals the position of the nodal planes of the molecular orbitals from which ionization occurs. The experimental results are supported by a theoretical tunneling model that includes and quantifies the splitting in the momentum distribution. The focus of the present article is to understand strong-field ionization from 3D-oriented asymmetric top molecules, in particular the suppression of electron emission in nodal planes of molecular orbitals. In the preceding article [Dimitrovski et al., Phys. Rev. A 83, 023405 (2011)] the focus is to understand the strong-field ionization of one-dimensionally-oriented polar molecules, in particular asymmetries in the emission direction of the photoelectrons.

Hansen, Jonas L. [Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C (Denmark); Holmegaard, Lotte; Kalhoej, Line; Kragh, Sofie Louise [Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Stapelfeldt, Henrik [Department of Chemistry, Aarhus University, DK-8000 Aarhus C (Denmark); Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C (Denmark); Filsinger, Frank; Meijer, Gerard; Kuepper, Jochen; Dimitrovski, Darko; Abu-samha, Mahmoud; Martiny, Christian Per Juul; Madsen, Lars Bojer [Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, D-14195 Berlin (Germany); Lundbeck Foundation Theoretical Center for Quantum System Research, Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark)

2011-02-15T23:59:59.000Z

293

Relativistic second-harmonic generation of a laser from underdense plasmas  

Science Conference Proceedings (OSTI)

A high intensity laser obliquely incident on a vacuum-plasma interface produces second-harmonic radiation in the reflected component. The efficiency of second-harmonic generation increases with the angle of incidence, up to critical angle of incidence (our model is not valid beyond critical angle of incidence). The efficiency also depends on electron density, showing a maximum at {omega}{sub p}{sup 2}/{omega}{sup 2} congruent with 0.7, where {omega}{sub p} and {omega} are relativistic plasma frequency and laser frequency, respectively. The efficiency of second-harmonic generation increases sharply with laser intensity in the nonrelativistic regime and saturates at higher intensities. The intensity of the second harmonic is proportional to square of the laser intensity at low pump laser intensities and tends to proportional to laser intensity in the strong relativistic regime.

Singh, K.P.; Gupta, D.N.; Yadav, Sushila; Tripathi, V.K. [Computational Plasma Dynamics Laboratory, Mechanical Engineering, Kettering University, Flint, Michigan 48504 (United States); Department of Physics, Indian Institute of Technology, New Delhi 110016 (India)

2005-01-01T23:59:59.000Z

294

High temperature thermographic measurements of laser heated silica  

SciTech Connect

In situ spatial and temporal surface temperature profiles of CO{sub 2} laser-heated silica were obtained using a long wave infrared (LWIR) HgCdTe camera. Solutions to the linear diffusion equation with volumetric and surface heating are shown to describe the temperature evolution for a range of beam powers, over which the peak surface temperature scales linearly with power. These solutions were used with on-axis steady state and transient experimental temperatures to extract thermal diffusivity and conductivity for a variety of materials, including silica, spinel, sapphire, and lithium fluoride. Experimentally-derived thermal properties agreed well with reported values and, for silica, thermal conductivity and diffusivity are shown to be approximately independent of temperature between 300 and 2800K. While for silica our analysis based on a temperature independent thermal conductivity is shown to be accurate, for other materials studied this treatment yields effective thermal properties that represent reasonable approximations for laser heating. Implementation of a single-wavelength radiation measurement in the semi-transparent regime is generally discussed, and estimates of the apparent temperature deviation from the actual outer surface temperature are also presented. The experimental approach and the simple analysis presented yield surface temperature measurements that can be used to validate more complex physical models, help discriminate dominant heat transport mechanisms, and to predict temperature distribution and evolution during laser-based material processing.

Elhadj, S; Yang, S T; Matthews, M J; Cooke, D J; Bude, J D; Johnson, M; Feit, M; Draggoo, V; Bisson, S E

2009-11-02T23:59:59.000Z

295

Analytic fluid theory of beam spiraling in high-intensity cyclotrons  

E-Print Network (OSTI)

Using a two-dimensional fluid description, we investigate the nonlinear radial-longitudinal dynamics of intense beams in isochronous cyclotrons in the nonrelativistic limit. With a multiscale analysis separating the time ...

Cerfon, A. J.

296

Generalized Kapchinskij-Vladimirskij Distribution and Envelope Equation for High-intensity Beams in a Coupled Transverse Focusing Lattice  

SciTech Connect

In an uncoupled lattice, the Kapchinskij-Vladimirskij (KV) distribution function first analyzed in 1959 is the only known exact solution of the nonlinear Vlasov-Maxwell equations for high- intensity beams including self-fields in a self-consistent manner. The KV solution is generalized here to high-intensity beams in a coupled transverse lattice using the recently developed generalized Courant-Snyder invariant for coupled transverse dynamics. This solution projects to a rotating, pulsating elliptical beam in transverse configuration space, determined by the generalized matrix envelope equation.

Hong Qin, Moses Chung, and Ronald C. Davidson

2009-11-20T23:59:59.000Z

297

Laser Radiometry  

Science Conference Proceedings (OSTI)

... over a wide range of powers, energies, and wavelengths. ... the SI units for laser power and energy. ... Novel power meter for high-efficiency laser diode ...

2012-04-18T23:59:59.000Z

298

Generation and use of high power 213 nm and 266 nm laser radiation and tunable 210-400 nm laser radiation with BBO crystal matrix array  

SciTech Connect

A 213 nm laser beam is capable of single photon ablative photodecomposition for the removal of a polymer or biological material substrate. Breaking the molecular bonds and displacing the molecules away from the substrate in a very short time period results in most of the laser photon energy being carried away by the displaced molecules, thus minimizing thermal damage to the substrate. The incident laser beam may be unfocussed and is preferably produced by quintupling the 1064 nm radiation from a Nd:YAG solid state laser, i.e., at 213 nm. In one application, the 213 nm laser beam is expanded in cross section and directed through a plurality of small beta barium borate (BBO) crystals for increasing the energy per photon of the laser radiation directed onto the substrate. The BBO crystals are arranged in a crystal matrix array to provide a large laser beam transmission area capable of accommodating high energy laser radiation without damaging the BBO crystals. The BBO crystal matrix array may also be used with 266 nm laser radiation for carrying out single or multi photon ablative photodecomposition. The BBO crystal matrix array may also be used in an optical parametric oscillator mode to generate high power tunable laser radiation in the range of 210-400 nm.

Gruen, Dieter M. (Downers Grove, IL)

2000-01-01T23:59:59.000Z

299

Vapor-Phase-Deposited Organosilane Coatings as "Hardening" Agents for High-Peak-Power Laser Optics  

Science Conference Proceedings (OSTI)

Multilayer-dielectric (MLD) diffraction gratings are used in high-power laser systems to compress laser-energy pulses. The peak power deliverable on target for these short-pulse petawatt class systems is limited by the laser-damage resistance of the optical components in the system, especially the MLD gratings. Recent experiments in our laboratory have shown that vapor treatment of MLD gratings at room temperature with organosilanes such as hexamethyldisilazane (HMDS) produces an increase in their damage threshold as compared to uncoated MLD grating control samples.

Marshall, K.L.; Culakova, Z.; Ashe, B.; Giacofei, C.; Rigatti, A.L.; Kessler, T.J.; Schmid, A.W.; Oliver, J.B.; Kozlov, A.

2008-01-07T23:59:59.000Z

300

Picosecond laser structuration under high pressures: Observation of boron nitride nanorods  

SciTech Connect

We report on picosecond UV-laser processing of hexagonal boron nitride (BN) at moderately high pressures above 500 bar. The main effect is specific to the ambient gas and laser pulse duration in the ablation regime: when samples are irradiated by 5 or 0.45 ps laser pulses in nitrogen gas environment, multiple nucleation of a new crystalline product-BN nanorods-takes place. This process is triggered on structural defects, which number density strongly decreases upon recrystallization. Nonlinear photon absorption by adsorbed nitrogen molecules is suggested to mediate the nucleation growth. High pressure is responsible for the confinement and strong backscattering of ablation products. A strong surface structuring also appears at longer 150 ps laser irradiation in similar experimental conditions. However, the transformed product in this case is amorphous strongly contaminated by boron suboxides B{sub x}O{sub y}.

Museur, Luc [Laboratoire de Physique des Lasers-LPL CNRS, Institut Galilee, Universite Paris 13, 93430 Villetaneuse (France); Petitet, Jean-Pierre; Kanaev, Andrei V. [Laboratoire d' Ingenierie des Materiaux et des Hautes Pressions-LIMHP CNRS, Institut Galilee, Universite Paris 13, 93430 Villetaneuse (France); Michel, Jean-Pierre [Laboratoire d' Ingenierie des Materiaux et des Hautes Pressions-LIMHP CNRS, Institut Galilee, Universite Paris 13, 93430 Villetaneuse (France); Laboratoire des Proprietes Mecaniques et Thermodynamiques des Materiaux-LPMTM CNRS, Institut Galilee, Universite Paris 13, 93430 Villetaneuse (France); Marine, Wladimir [Centre Interdisciplinaire de Nanoscience de Marseille-CINaM, UPR CNRS 3118, Faculte des Science de Luminy, 13288 Marseille (France); Anglos, Demetrios [Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (IESL-FORTH), 71110 Heraklion, Crete (Greece); Fotakis, Costas [Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (IESL-FORTH), 71110 Heraklion, Crete (Greece); Department of Physics, University of Crete, Heraklion, Crete (Greece)

2008-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" 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

Conceptual design of a high-intensity positron source for the Advanced Neutron Source  

SciTech Connect

The Advanced Neutron Source (ANS) is a planned new basic and applied research facility based on a powerful steady-state research reactor that provides neutrons for measurements and experiments in the fields of materials science and engineering, biology, chemistry, materials analysis, and nuclear science. The useful neutron flux will be at least five times more than is available in the world`s best existing reactor facility. Construction of the ANS provides a unique opportunity to build a positron spectroscopy facility (PSF) with very-high-intensity beams based on the radioactive decay of a positron-generating isotope. The estimated maximum beam current is 1000 to 5000 times higher than that available at the world`s best existing positron research facility. Such an improvement in beam capability, coupled with complementary detectors, will reduce experiment durations from months to less than one hour while simultaneously improving output resolution. This facility will remove the existing barriers to the routine use of positron-based analytical techniques and will be a giant step toward realization of the full potential of the application of positron spectroscopy to materials science. The ANS PSF is based on a batch cycle process using {sup 64}Cu isotope as the positron emitter and represents the status of the design at the end of last year. Recent work not included in this report, has led to a proposal for placing the laboratory space for the positron experiments outside the ANS containment; however, the design of the positron source is not changed by that relocation. Hydraulic and pneumatic flight tubes transport the source material between the reactor and the positron source where the beam is generated and conditioned. The beam is then transported through a beam pipe to one of several available detectors. The design presented here includes all systems necessary to support the positron source, but the beam pipe and detectors have not been addressed yet.

Hulett, L.D.; Eberle, C.C.

1994-12-01T23:59:59.000Z

302

Inertial fusion with ultra-powerful lasers  

SciTech Connect

Ultra-high intensity lasers can be used to ignite ICF capsules with a few tens of kilojoules of light and can lead to high gain with as little as 100 kilojoules of incident laser light. We propose a scheme with three phases. First, a capsule is imploded as in the conventional approach to inertial fusion to assemble a high density fuel configuration. Second, a hole is bored through capsule corona composed of ablated material, pushing critical density close to the high density core of the capsule, by employing the ponderomotive force associated with high intensity laser light. Finally, the fuel is ignited by suprathermal electrons, produced in the high intensity laser plasma interactions, which propagate from critical density to this high density core. This paper reviews two models of energy gain in ICF capsules and explains why ultra-high intensity lasers allow access to the model producing the higher gains. This new scheme also drastically reduces the difficulty of the implosion and thereby allows lower quality fabrication and less stringent beam quality and symmetry requirements from the implosion driver. The difficulty of the fusion scheme is transferred to the technological difficulty of producing the ultra-high-intensity laser and of transporting this energy to the fuel.

Tabak, M.; Hammer, J.; Glinsky, M.; Kruer, W.; Wilks, S.; Woodworth, J.; Campbell, E.M.; Perry, M.D.; Mason, R.

1993-10-01T23:59:59.000Z

303

Laser isotope separation by multiple photon absorption  

DOE Patents (OSTI)

Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, in the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO.sub.2 laser light may be used to highly enrich .sup.34 S in natural SF.sub.6 and .sup.11 B in natural BCl.sub.3.

Robinson, C. Paul (Los Alamos, NM); Rockwood, Stephen D. (Los Alamos, NM); Jensen, Reed J. (Los Alamos, NM); Lyman, John L. (Los Alamos, NM); Aldridge, III, Jack P. (Los Alamos, NM)

1977-01-01T23:59:59.000Z

304

Laser isotope separation by multiple photon absorption  

DOE Patents (OSTI)

Multiple photon absorption from an intense beam of infrared laser light may be used to induce selective chemical reactions in molecular species which result in isotope separation or enrichment. The molecular species must have a sufficient density of vibrational states in its vibrational manifold that, is the presence of sufficiently intense infrared laser light tuned to selectively excite only those molecules containing a particular isotope, multiple photon absorption can occur. By this technique, for example, intense CO.sub.2 laser light may be used to highly enrich .sup.34 S in natural SF.sub.6 and .sup.11 B in natural BCl.sub.3.

Robinson, C. Paul (Los Alamos, NM); Rockwood, Stephen D. (Los Alamos, NM); Jensen, Reed J. (Los Alamos, NM); Lyman, John L. (Los Alamos, NM); Aldridge, III, Jack P. (Los Alamos, NM)

1987-01-01T23:59:59.000Z

305

KrF laser path to high gain ICF (inertial confinement fusion) laboratory microfusion facility  

SciTech Connect

The krypton-fluoride laser has many desirable features for inertial confinement fusion. Because it is a gas laser capable of operation with high efficiency, it is the only known laser candidate capable of meeting the driver requirements for inertial fusion energy (IFE) production. Los Alamos National Laboratory has defined a program plan to develop KrF lasers for IFE production. This plan develops the KrF laser and demonstrates the target performance in single-pulse facilities. A 100-kJ Laser Target Test Facility (LTTF) is proposed as the next step, to be followed by a 3 to 10-MJ Laboratory Microfusion Facility (LMF). The LTTF will resolve many target physics issues and accurately define the driver energy required for the LMF. It is also proposed that the technology development for IFE, such as the high-efficiency, high-reliability, repetitively pulsed driver, the reactor, mass production of targets, and the mechanism of injecting targets be developed in parallel with the single-pulse facilities. 11 refs., 4 figs.

Harris, D.B.; Sullivan, J.A.; Figueiro, J.F.; Cartwright, D.C.; McDonald, T.E.; Hauer, A.A.; Coggeshall, S.V.; Younger, S.M.

1990-01-01T23:59:59.000Z

306

Cladding glass ceramic for use in high powered lasers  

DOE Patents (OSTI)

A Cu-doped/Fe-doped low expansion glass ceramic composition comprising in Wt. %: SiO{sub 2} 50--65; Al{sub 2}O{sub 3} 18--27; P{sub 2}O{sub 5} 0--10; Li{sub 2}O 2--6; Na{sub 2}O 0--2; K{sub 2}O 0--2; B{sub 2}O{sub 3} 0--1; MgO 0--4; ZnO 0--5; CaO 0--4; BaO 0--5; TiO{sub 2} 1--3; ZrO{sub 3} 1--3; As{sub 2}O{sub 3} 0--1.5; Sb{sub 2}O{sub 3} 0--1.5; CuO 0--3; and Fe{sub 2}O{sub 3} 0--1 wherein the total amount of SiO{sub 2}, Al{sub 2}O{sub 3} and P{sub 2}O{sub 5} is 80--89 wt. %, and said glass ceramic contains as a dopant 0.1--3 wt. % CuO, 0.1--1 wt. % Fe{sub 2}O{sub 3} or a combined CuO+Fe{sub 2}O{sub 3} amount of 0.1--4 wt. %. The glass ceramic composition is suitable for use as a cladding material for solid laser energy storage mediums as well as for use in beam attenuators for measuring laser energy level and beam blocks or beam dumps used for absorbing excess or unused laser energy.

Marker, A.J.; Campbell, J.H.

1998-02-17T23:59:59.000Z

307

Cladding glass ceramic for use in high powered lasers  

DOE Green Energy (OSTI)

A Cu-doped/Fe-doped low expansion glass ceramic composition comprising in Wt. %: SiO{sub 2} 50--65; Al{sub 2}O{sub 3} 18--27; P{sub 2}O{sub 5} 0--10; Li{sub 2}O 2--6; Na{sub 2}O 0--2; K{sub 2}O 0--2; B{sub 2}O{sub 3} 0--1; MgO 0--4; ZnO 0--5; CaO 0--4; BaO 0--5; TiO{sub 2} 1--3; ZrO{sub 3} 1--3; As{sub 2}O{sub 3} 0--1.5; Sb{sub 2}O{sub 3} 0--1.5; CuO 0--3; and Fe{sub 2}O{sub 3} 0--1 wherein the total amount of SiO{sub 2}, Al{sub 2}O{sub 3} and P{sub 2}O{sub 5} is 80--89 wt. %, and said glass ceramic contains as a dopant 0.1--3 wt. % CuO, 0.1--1 wt. % Fe{sub 2}O{sub 3} or a combined CuO+Fe{sub 2}O{sub 3} amount of 0.1--4 wt. %. The glass ceramic composition is suitable for use as a cladding material for solid laser energy storage mediums as well as for use in beam attenuators for measuring laser energy level and beam blocks or beam dumps used for absorbing excess or unused laser energy.

Marker, Alexander J. (Moscow, PA); Campbell, John H. (Livermore, CA)

1998-01-01T23:59:59.000Z

308

Speckle-free laser imaging  

E-Print Network (OSTI)

Many imaging applications require increasingly bright illumination sources, motivating the replacement of conventional thermal light sources with light emitting diodes (LEDs), superluminescent diodes (SLDs) and lasers. Despite their brightness, lasers and SLDs are poorly suited for full-field imaging applications because their high spatial coherence leads to coherent artifacts known as speckle that corrupt image formation. We recently demonstrated that random lasers can be engineered to provide low spatial coherence. Here, we exploit the low spatial coherence of specifically-designed random lasers to perform speckle-free full-field imaging in the setting of significant optical scattering. We quantitatively demonstrate that images generated with random laser illumination exhibit higher resolution than images generated with spatially coherent illumination. By providing intense laser illumination without the drawback of coherent artifacts, random lasers are well suited for a host of full-field imaging applicatio...

Redding, Brandon; Cao, Hui

2011-01-01T23:59:59.000Z

309

Experimental Estimate of Beam Loading and Minimum rf Voltage for Acceleration of High Intensity Beam in the Fermilab Booster  

E-Print Network (OSTI)

The difference between the rf voltage seen by the beam and the accelerating voltage required to match the rate of change of the Booster magnetic field is used to estimate the energy loss per beam turn. Because the rf voltage (RFSUM) and the synchronous phase can be experimentally measured, they can be used to calculate the effective accelerating voltage. Also an RFSUM reduction technique has been applied to measure experimentally the RFSUM limit at which the beam loss starts. With information on beam energy loss, the running conditions, especially for the high intensity beam, can be optimized in order to achieve a higher intensity beam from the Fermilab Booster.

Yang, X; Norem, J; Yang, Xi

2004-01-01T23:59:59.000Z

310

Experimental estimate of beam loading and minimum rf voltage for acceleration of high intensity beam in the Fermilab Booster  

SciTech Connect

The difference between the rf voltage seen by the beam and the accelerating voltage required to match the rate of change of the Booster magnetic field is used to estimate the energy loss per beam turn. Because the rf voltage (RFSUM) and the synchronous phase can be experimentally measured, they can be used to calculate the effective accelerating voltage. Also an RFSUM reduction technique has been applied to measure experimentally the RFSUM limit at which the beam loss starts. With information on beam energy loss, the running conditions, especially for the high intensity beam, can be optimized in order to achieve a higher intensity beam from the Fermilab Booster.

Xi Yang; Charles M Ankenbrandt and Jim Norem

2004-04-01T23:59:59.000Z

311

Stimulated Brillouin scattering mirror system, high power laser and laser peening method and system using same  

DOE Patents (OSTI)

A laser system, such as a master oscillator/power amplifier system, comprises a gain medium and a stimulated Brillouin scattering SBS mirror system. The SBS mirror system includes an in situ filtered SBS medium that comprises a compound having a small negative non-linear index of refraction, such as a perfluoro compound. An SBS relay telescope having a telescope focal point includes a baffle at the telescope focal point which blocks off angle beams. A beam splitter is placed between the SBS mirror system and the SBS relay telescope, directing a fraction of the beam to an alternate beam path for an alignment fiducial. The SBS mirror system has a collimated SBS cell and a focused SBS cell. An adjustable attenuator is placed between the collimated SBS cell and the focused SBS cell, by which pulse width of the reflected beam can be adjusted.

Dane, C. Brent (Livermore, CA); Hackel, Lloyd (Livermore, CA); Harris, Fritz B. (Rocklin, CA)

2007-04-24T23:59:59.000Z

312

Specification of optical components for a high average-power laser environment  

Science Conference Proceedings (OSTI)

Optical component specifications for the high-average-power lasers and transport system used in the Atomic Vapor Laser Isotope Separation (AVLIS) plant must address demanding system performance requirements. The need for high performance optics has to be balanced against the practical desire to reduce the supply risks of cost and schedule. This is addressed in optical system design, careful planning with the optical industry, demonstration of plant quality parts, qualification of optical suppliers and processes, comprehensive procedures for evaluation and test, and a plan for corrective action.

Taylor, J.R.; Chow, R.; Rinmdahl, K.A.; Willis, J.B.; Wong, J.N.

1997-06-25T23:59:59.000Z

313

High-power laser and arc welding of thorium-doped iridium alloys  

SciTech Connect

The arc and laser weldabilities of two Ir-0.3% W alloys containing 60 and 200 wt ppM Th have been investigated. The Ir-.03% W alloy containing 200 wt ppM Th is severely prone to hot cracking during gas tungsten-arc welding. Weld metal cracking results from the combined effects of heat-affected zone liquation cracking and solidification cracking. Scanning electron microscopic analysis of the fractured surface revealed patches of low-melting eutectic. The cracking is influenced to a great extent by the fusion zone microstructure and thorium content. The alloy has been welded with a continuous-wave high-power CO/sub 2/ laser system with beam power ranging from 5 to 10 kW and welding speeds of 8 to 25 mm/s. Successful laser welds without hot cracking have been obtained in this particular alloy. This is attributable to the highly concentrated heat source available in the laser beam and the refinement in fusion zone microstructure obtained during laser welding. Efforts to refine the fusion zone structure during gas tungsten-arc welding of Ir-0.3 % W alloy containing 60 wt ppM Th were partially successful. Here transverse arc oscillation during gas tungsten-arc welding refines the fusion zone structure to a certain extent. However, microstructural analysis of this alloy's laser welds indicates further refinement in the fusion zone microstructure than in that from the gas tungsten-arc process using arc oscillations. The fusion zone structure of the laser weld is a strong function of welding speed.

David, S.A.; Liu, C.T.

1980-05-01T23:59:59.000Z

314

High-power laser and arc welding of thorium-doped iridium alloys  

DOE Green Energy (OSTI)

The arc and laser weldabilities of two Ir-0.3% W alloys containing 60 and 200 wt ppM Th have been investigated. The Ir-.03% W alloy containing 200 wt ppM Th is severely prone to hot cracking during gas tungsten-arc welding. Weld metal cracking results from the combined effects of heat-affected zone liquation cracking and solidification cracking. Scanning electron microscopic analysis of the fractured surface revealed patches of low-melting eutectic. The cracking is influenced to a great extent by the fusion zone microstructure and thorium content. The alloy has been welded with a continuous-wave high-power CO/sub 2/ laser system with beam power ranging from 5 to 10 kW and welding speeds of 8 to 25 mm/s. Successful laser welds without hot cracking have been obtained in this particular alloy. This is attributable to the highly concentrated heat source available in the laser beam and the refinement in fusion zone microstructure obtained during laser welding. Efforts to refine the fusion zone structure during gas tungsten-arc welding of Ir-0.3 % W alloy containing 60 wt ppM Th were partially successful. Here transverse arc oscillation during gas tungsten-arc welding refines the fusion zone structure to a certain extent. However, microstructural analysis of this alloy's laser welds indicates further refinement in the fusion zone microstructure than in that from the gas tungsten-arc process using arc oscillations. The fusion zone structure of the laser weld is a strong function of welding speed.

David, S.A.; Liu, C.T.

1980-05-01T23:59:59.000Z

315

Intense multimicrojoule high-order harmonics generated from neutral atoms of In{sub 2}O{sub 3} nanoparticles  

Science Conference Proceedings (OSTI)

We studied high-order harmonic generation from plasma that contains an abundance of indium oxide nanoparticles. We found that harmonics from nanoparticle-containing plasma are considerably more intense than from plasma produced on the In{sub 2}O{sub 3} bulk target, with high-order harmonic energy ranging from 6 {mu}J (for the ninth harmonic) to 1 {mu}J (for the 17th harmonic) in the former case. The harmonic cutoff from nanoparticles was at the 21st order, which is lower than that observed using indium oxide solid target. By comparing the harmonic spectra obtained from solid and nanoparticle indium oxide targets, we concluded that intense harmonics in the latter case are dominantly generated from neutral atoms of the In{sub 2}O{sub 3} nanoparticles.

Elouga Bom, L. B.; Abdul-Hadi, J.; Vidal, F.; Ozaki, T. [Centre Energie, Materiaux et Telecommunications, Institut National de la Recherche Scientifique, 1650 Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada); Ganeev, R. A. [Centre Energie, Materiaux et Telecommunications, Institut National de la Recherche Scientifique, 1650 Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada); Scientific Association Akadempribor, Uzbekistan Academy of Sciences, Akademgorodok, Tashkent 100125 (Uzbekistan)

2009-03-16T23:59:59.000Z

316

High intensity uranium beams from the superHILAC and the bevatron: final report  

Science Conference Proceedings (OSTI)

The two injectors formerly used at the SuperHILAC were a 750-kV air-insulated Cockcroft-Walton (EVE) and a 2.5-MV pressurized HV multiplier (ADAM). The EVE injector can deliver adequate intensities of ions up to mass 40 (argon). The ADAM injector can accelerate ions with lower charge-to-mass ratios, and they can produce beams of heavier ions. The intensity of these beams decreases as the mass number increases, with the lowest practical intensity being achieved with lead beams. Experience with the two existing injectors provided substantial help in defining the general requirements for a new injector which would provide ample beams above mass 40. The requirements for acceptance by the first tank of the SuperHILAC are a particle velocity ..beta.. = 0.0154 (corresponding to an energy of 113 keV/amu) and a charge-to-mass ratio of 0.046 or larger. Present ion source performance dictates an air-insulated Cockcroft-Walton as a pre-accelerator because of its easy accessibility and its good overall reliability. The low charge state ions then receive further acceleration and, if necessary, subsequent stripping to the required charge state before injection into the SuperHILAC. A low-beta linac of the Widereoe type has been built to perform this acceleration. The injector system described consists of a Cockcroft-Walton pre-injector, injection beam lines and isotope analysis, a low-velocity linear accelerator, and SuperHILAC control center modifications.

Not Available

1982-03-01T23:59:59.000Z

317

X-ray Methods in High-Intensity Discharges and Metal-Halide Lamps: X-ray Induced Fluorescence  

SciTech Connect

We describe the use of x-ray induced fluorescence to study metal-halide high-intensity discharge lamps and to measure equilibrium vapor pressures of metal-halide salts. The physical principles of metal-halide lamps, relevant aspects of x-ray-atom interactions, the experimental method using synchrotron radiation, and x-ray induced fluorescence measurements relevant to metal-halide lamps are covered.

Curry, John J.; Lapatovich, Walter P.; Henins, Albert (NIST)

2011-12-09T23:59:59.000Z

318

Refractory oxide hosts for a high power, broadly tunable laser with high quantum efficiency and method of making same  

DOE Patents (OSTI)

Refractory oxide crystals having high-quantum efficiency and high thermal stability for use as broadly tunable laser host materials. The crystals are formed by removing hydrogen from a single crystal of the oxide material to a level below about 10/sup 12/ protons per cm/sup 3/ and subsequently thermochemically reducing the oxygen content of the crystal to form sufficient oxygen anion vacancies so that short-lived F/sup +/ luminescence is produced when the crystal is optically excited.

Chen, Yok; Gonzalez, R.

1985-07-03T23:59:59.000Z

319

Refractory oxide hosts for a high power, broadly tunable laser with high quantum efficiency and method of making same  

DOE Patents (OSTI)

Refractory oxide crystals having high-quantum efficiency and high thermal stability for use as broadly tunable laser host materials. The crystals are formed by removing hydrogen from a single crystal of the oxide material to a level below about 10.sup.12 protons per cm.sup.3 and subsequently thermochemically reducing the oxygen content of the crystal to form sufficient oxygen anion vacancies so that short-lived F.sup.+ luminescence is produced when the crystal is optically excited.

Chen, Yok (Oak Ridge, TN); Gonzalez, Roberto (Madrid, ES)

1986-01-01T23:59:59.000Z

320

The Use of Large Transparent Ceramics in a High Powered, Diode Pumped Solid State Laser  

SciTech Connect

The advent of large transparent ceramics is one of the key enabling technological advances that have shown that the development of very high average power compact solid state lasers is achievable. Large ceramic neodymium doped yttrium aluminum garnet (Nd:YAG) amplifier slabs are used in Lawrence Livermore National Laboratory's (LLNL) Solid State Heat Capacity Laser (SSHCL), which has achieved world record average output powers in excess of 67 kilowatts. We will describe the attributes of using large transparent ceramics, our present system architecture and corresponding performance; as well as describe our near term future plans.

Yamamoto, R; Bhachu, B; Cutter, K; Fochs, S; Letts, S; Parks, C; Rotter, M; Soules, T

2007-09-24T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" 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

Science on high-energy lasers: From today to the NIF  

SciTech Connect

This document presents both a concise definition of the current capabilities of high energy lasers and a description of capabilities of the NIF (National Ignition Facility). Five scientific areas are discussed (Astrophysics, Hydrodynamics, Material Properties, Plasma Physics, Radiation Sources, and Radiative Properties). In these five areas we project a picture of the future based on investigations that are being carried on today. Even with this very conservative approach we find that the development of new higher energy lasers will make many extremely exciting areas accessible to us.

Lee, R.W.; Petrasso, R.; Falcone, R.W.

1995-01-01T23:59:59.000Z

322

Radiation from laser accelerated electron bunches: Coherent terahertz and femtosecond X-rays  

E-Print Network (OSTI)

by an intense ultrashort laser pulse,” Science, vol. 298,generated from intense laser-plasma interactions,” Appl.monochromatic x-rays in the laser synchrotron source

2004-01-01T23:59:59.000Z

323

Ultrashort pulse high repetition rate laser system for biological tissue processing  

DOE Patents (OSTI)

A method and apparatus is disclosed for fast, efficient, precise and damage-free biological tissue removal using an ultrashort pulse duration laser system operating at high pulse repetition rates. The duration of each laser pulse is on the order of about 1 fs to less than 50 ps such that energy deposition is localized in a small depth and occurs before significant hydrodynamic motion and thermal conduction, leading to collateral damage, can take place. The depth of material removed per pulse is on the order of about 1 micrometer, and the minimal thermal and mechanical effects associated with this ablation method allows for high repetition rate operation, in the region 10 to over 1000 Hertz, which, in turn, achieves high material removal rates. The input laser energy per ablated volume of tissue is small, and the energy density required to ablate material decreases with decreasing pulse width. The ablation threshold and ablation rate are only weakly dependent on tissue type and condition, allowing for maximum flexibility of use in various biological tissue removal applications. The use of a chirped-pulse amplified Titanium-doped sapphire laser is disclosed as the source in one embodiment.

Neev, Joseph (Laguna Beach, CA); Da Silva, Luiz B. (Danville, CA); Matthews, Dennis L. (Moss Beach, CA); Glinsky, Michael E. (Livermore, CA); Stuart, Brent C. (Fremont, CA); Perry, Michael D. (Livermore, CA); Feit, Michael D. (Livermore, CA); Rubenchik, Alexander M. (Livermore, CA)

1998-01-01T23:59:59.000Z

324

Design of a High Intensity Neutron Source for Neutron-Induced Fission Yield Studies  

E-Print Network (OSTI)

The upgraded IGISOL facility with JYFLTRAP, at the accelerator laboratory of the University of Jyv\\"askyl\\"a, has been supplied with a new cyclotron which will provide protons of the order of 100 {\\mu}A with up to 30 MeV energy, or deuterons with half the energy and intensity. This makes it an ideal place for measurements of neutron-induced fission products from various actinides, in view of proposed future nuclear fuel cycles. The groups at Uppsala University and University of Jyv\\"askyl\\"a are working on the design of a neutron converter that will be used as neutron source in fission yield studies. The design is based on simulations with Monte Carlo codes and a benchmark measurement that was recently performed at The Svedberg Laboratory in Uppsala. In order to obtain a competitive count rate the fission targets will be placed very close to the neutron converter. The goal is to have a flexible design that will enable the use of neutron fields with different energy distributions. In the present paper, some considerations for the design of the neutron converter will be discussed, together with different scenarios for which fission targets and neutron energies to focus on.

M. Lantz; D. Gorelov; A. Jokinen; V. S. Kolhinen; A. Mattera; H. Penttilä; S. Pomp; V. Rakopoulos; S. Rinta-Antila; A. Solders

2013-04-09T23:59:59.000Z

325

High intensity discharge lamp self-adjusting ballast system sensitive to the radiant energy or heat of the lamp  

SciTech Connect

This patent describes a self-adjusting ballast system for mercury vapor, high intensity discharge lamps having outputs of 100 watts or greater, comprising: a direct current source; a lamp circuit containing a high intensity discharge lamp; sensing means for sensing the radiant energy output of the lamp; a pulse width modulator which, in response to the output of the sensing means, varies the width of the pulses that power the lamp during warm-up of the lamp; a high frequency oscillator; a DC to AC converter that converts current from the direct source to pulses of alternating current for powering the lamp, the converter comprising: at least one switch for gating current to the lamp; a switch control means, responsive to the high frequency oscillator, for controlling the switch and controlling the frequency of the alternating current pulses that power the lamp; current sensing means for sensing the current being supplied to the lamp; and current control means for limiting the current through the lamp to a predetermined safe level when the current sensed by the current sensing means exceeds a reference value.

Kuhnel, D.S.; Ottenstein, S.A.

1987-07-21T23:59:59.000Z

326

High-power SRS lasers - coherent summators (the way it was)  

Science Conference Proceedings (OSTI)

The history of the research works performed under the guidance of H.G. Basov and aimed at developing high-energy lasers - coherent summators (CSs) - based on stimulated Raman scattering (SRS) in liquid nitrogen and liquid oxygen is reported. The work was performed jointly by researchers of FIAN [the Laboratory of Quantum Radiophysics (LQRP)] and VNIIEF. Many problems were solved as a result of these studies. Liquid nitrogen and oxygen were found to be optimal active media for high-power SRS lasers with high energy per pulse. A method for purifying these cryogenic liquids from micro- and nanoimpurities was developed, which made it possible to eliminate nonlinear loss of pump radiation and converted radiation in the active medium and ensure effective operation of SRS lasers - coherent summators (SRSL CSs) with high output energy. Cryogenic cells providing high optical homogeneity of liquid nitrogen and oxygen were developed, which ensured low (at a level of 0.1 mrad) divergence of converted radiation with high energy density. Raster focusing systems providing optimal concentration of pump radiation in the active medium were designed. These studies resulted in the development of high-power highenergy SRSL CSs with a low beam divergence, based on liquid nitrogen ({lambda}{sub S} = 1.89 {mu}m) and liquid oxygen ({lambda}{sub S} = 1.65 {mu}m), with pumping by explosively pumped iodine lasers (EPILs) ({lambda}{sub p} = 1.315 {mu}m). The characteristics of the SRSL CSs developed were record for that time (the end of 1960s and the beginning of 1970s): energy up to 2.5 kJ per 10-{mu}s pulse, beam divergence {approx}10{sup -4} rad, and beam energy density of several hundreds of J cm{sup -2}. (special issue devoted to the 90th anniversary of n.g. basov)

Grasiuk, Arkadii Z; Zubarev, I G; Efimkov, V F; Smirnov, V G [P N Lebedev Physical Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2012-12-31T23:59:59.000Z

327

High-speed Photography of Pyrotechnic Materials and Components with a Coppper Vapor Laser  

SciTech Connect

The evaluation of the properties of energetic materials, such as burn rate and ignition energy, is of primary importance in understanding their reactions and the functioning of devices containing them. One method for recording such information is high-speed photography at rates of up to 20,000 images per second. When a copper vapor lazer is synchronized with the camera, laser-illuminated images can be recorded that detail the performance of a material or component in a manner never before possible. Recent results from high-speed photography of several pyrotechnic materials and devices will be presented. These include a pyrotechnic torch, laser ignition of high explosives, and a functioning igniter. Equilibrium chemical computations have recently been begun on the pyrotechnic torch to obtain flame compositions and temperatures. The results of these calculations, and their explanation of the change in torch function with composition, will be discussed.

Dosser, Larry R.; Reed, John W.; Stark, Margaret A.

1978-10-01T23:59:59.000Z

328

Laser particle sorter  

DOE Patents (OSTI)

Method and apparatus are provided for sorting particles, such as biological particles. A first laser is used to define an optical path having an intensity gradient which is effective to propel the particles along the path but which is sufficiently weak that the particles are not trapped in an axial direction. A probe laser beam is provided for interrogating the particles to identify predetermined phenotypical characteristics of the particles. A second laser beam is provided to intersect the driving first laser beam, wherein the second laser beam is activated by an output signal indicative of a predetermined characteristic. The second laser beam is switchable between a first intensity and a second intensity, where the first intensity is effective to displace selected particles from the driving laser beam and the second intensity is effective to propel selected particles along the deflection laser beam. The selected particles may then be propelled by the deflection beam to a location effective for further analysis. 2 figs.

Martin, J.C.; Buican, T.N.

1987-11-30T23:59:59.000Z

329

Laser focus compensating sensing and imaging device  

DOE Patents (OSTI)

A laser focus compensating sensing and imaging device permits the focus of a single focal point of different frequency laser beams emanating from the same source point. In particular it allows the focusing of laser beams originating from the same laser device but having differing intensities so that a low intensity beam will not convert to a higher frequency when passing through a conversion crystal associated with the laser generating device. The laser focus compensating sensing and imaging device uses a cassegrain system to fold the lower frequency, low intensity beam back upon itself so that it will focus at the same focal point as a high intensity beam. An angular tilt compensating lens is mounted about the secondary mirror of the cassegrain system to assist in alignment. In addition cameras or CCD`s are mounted with the primary mirror to sense the focused image. A convex lens in positioned coaxial with the cassegrain system on the side of the primary mirror distal of the secondary for use in aligning a target with the laser beam. A first alternate embodiment includes a cassegrain system using a series of shuttles and an internally mounted dichroic mirror. A second alternate embodiment uses two laser focus compensating sensing and imaging devices for aligning a moving tool with a work piece.

Vann, C.S.

1992-12-31T23:59:59.000Z

330

FY96-98 Summary Report Mercury: Next Generation Laser for High Energy Density Physics SI-014  

SciTech Connect

The scope of the Mercury Laser project encompasses the research, development, and engineering required to build a new generation of diode-pumped solid-state lasers for Inertial Confinement Fusion (ICF). The Mercury Laser will be the first integrated demonstration of laser diodes, crystals, and gas cooling within a scalable laser architecture. This report is intended to summarize the progress accomplished during the first three years of the project. Due to the technological challenges associated with production of 900 nm diode-bars, heatsinks, and high optical-quality Yb:S-FAP crystals, the initial focus of the project was primarily centered on the R&D in these three areas. During the third year of the project, the R&D continued in parallel with the development of computer codes, partial activation of the laser, component testing, and code validation where appropriate.

Bayramian, A.; Beach, R.; Bibeau, C.; Chanteloup, J.-C.; Ebbers, C.; Emanuel, M.; Freitas, B.; Fulkerson, S.; Kanz, K.; Hinz, A.; Marshall, C.; Mills, S.; Nakano, H.; Orth, C.; Rothenberg, J.; Schaffers, K.; Seppala, L.; Skidmore, J.; Smith, L.; Sutton, S.; Telford, S.; Zapata, L.

2000-05-25T23:59:59.000Z

331

FY96-98 Summary Report Mercury: Next Generation Laser for High Energy Density Physics SI-014  

SciTech Connect

The scope of the Mercury Laser project encompasses the research, development, and engineering required to build a new generation of diode-pumped solid-state lasers for Inertial Confinement Fusion (ICF). The Mercury Laser will be the first integrated demonstration of laser diodes, crystals, and gas cooling within a scalable laser architecture. This report is intended to summarize the progress accomplished during the first three years of the project. Due to the technological challenges associated with production of 900 nm diode-bars, heatsinks, and high optical-quality Yb:S-FAP crystals, the initial focus of the project was primarily centered on the R&D in these three areas. During the third year of the project, the R&D continued in parallel with the development of computer codes, partial activation of the laser, component testing, and code validation where appropriate.

Bayramian, A; Beach, R; Bibeau, C; Chanteloup, J; Ebbers, C; Emanuel, M; Freitas, B; Fulkerson, S; Kanz, K; Hinz, A; Marshall, C; Mills, S; Nakano, H; Orth, C; Rothenberg, J; Schaffers, K; Seppala, L; Skidmore, I; Smith, L; Sutton, S; Telford, S; Zapata, L

2000-05-23T23:59:59.000Z

332

Laser-Triggered Lightning Laboratory Tests: Preparation for Testing at Mississippi State University High-Voltage Laboratory  

Science Conference Proceedings (OSTI)

Lightning diversion using laser technology could be operationally used in the power industry to protect sensitive facilities such as nuclear power plants and critical substations, control centers, and customer facilities. This report provides results to date and plans for large-scale, high-voltage laboratory testing of laser-triggered lightning technology.

1998-01-15T23:59:59.000Z

333

Laser ablation based fuel ignition  

DOE Patents (OSTI)

There is provided a method of fuel/oxidizer ignition comprising: (a) application of laser light to a material surface which is absorptive to the laser radiation; (b) heating of the material surface with the laser light to produce a high temperature ablation plume which emanates from the heated surface as an intensely hot cloud of vaporized surface material; and (c) contacting the fuel/oxidizer mixture with the hot ablation cloud at or near the surface of the material in order to heat the fuel to a temperature sufficient to initiate fuel ignition. 3 figs.

Early, J.W.; Lester, C.S.

1998-06-23T23:59:59.000Z

334

High harmonic attosecond pulse train amplification in a free electron laser  

SciTech Connect

It is shown using three-dimensional simulations that the temporal structure of an attosecond pulse train, such as that generated via high harmonic generation in noble gases, may be retained in a free electron laser amplifier through to saturation using a mode-locked optical klystron configuration. At wavelengths of {approx}12 nm, a train of attosecond pulses of widths {approx}300 as with peak powers in excess of 1 GW are predicted.

McNeil, B.W.; Sheehy, B.; Thompson, N.R.; Dunning, D.J.

2011-03-04T23:59:59.000Z

335

High-order-harmonic generation in gas with a flat-top laser beam  

Science Conference Proceedings (OSTI)

We present experimental and numerical results on high-order-harmonic generation with a flat-top laser beam. We show that a simple binary tunable phase plate, made of two concentric glass plates, can produce a flat-top profile at the focus of a Gaussian infrared beam. Both experiments and numerical calculations show that there is a scaling law between the harmonic generation efficiency and the increase of the generation volume.

Boutu, W.; Auguste, T.; Binazon, L.; Gobert, O.; Carre, B. [Service des Photons, Atomes et Molecules, CEA-Saclay, FR-91191 Gif-sur-Yvette Cedex (France); Boyko, O.; Valentin, C. [Laboratoire d'Optique Appliquee, UMR 7639 ENSTA/CNRS/Ecole Polytechnique, FR-91761 Palaiseau (France); Sola, I.; Constant, E.; Mevel, E. [Universite de Bordeaux, CEA, CNRS UMR 5107, CELIA (Centre Lasers Intenses et Applications), FR-33400 Talence (France); Balcou, Ph. [Laboratoire d'Optique Appliquee, UMR 7639 ENSTA/CNRS/Ecole Polytechnique, FR-91761 Palaiseau (France); Universite de Bordeaux, CEA, CNRS UMR 5107, CELIA (Centre Lasers Intenses et Applications), FR-33400 Talence (France); Merdji, H. [Service des Photons, Atomes et Molecules, CEA-Saclay, FR-91191 Gif-sur-Yvette Cedex (France); PULSE Institute for Ultrafast Energy Science, Stanford Linear Accelerator Center, Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025 (United States)

2011-12-15T23:59:59.000Z

336

Time-dependent polarization states of high power, ultrashort laser pulses during atmospheric propagation  

E-Print Network (OSTI)

We investigate, through simulation, the evolution of polarization states during atmospheric propagation of high power, ultrashort laser pulses. A delayed rotational response model handling arbitrary, transverse polarization couples both the amplitude and phase of the polarization states. We find that, while circularly and linearly polarized pulses maintain their polarization, elliptically polarized pulses become depolarized due to energy equilibration between left and right circularly polarized states. The depolarization can be detrimental to remote radiation generation schemes and obscures time-integrated polarization measurements.

Palastro, J P

2013-01-01T23:59:59.000Z

337

Optical pyrometer system for collisionless shock experiments in high-power laser-produced plasmas  

Science Conference Proceedings (OSTI)

A temporally and spatially resolved optical pyrometer system has been fielded on Gekko XII experiments. The system is based on the self-emission measurements with a gated optical imager (GOI) and a streaked optical pyrometer (SOP). Both detectors measure the intensity of the self-emission from laser-produced plasmas at the wavelength of 450 nm with a bandpass filter with a width of {approx}10 nm in FWHM. The measurements were calibrated with different methods, and both results agreed with each other within 30% as previously reported [T. Morita et al., Astrophys. Space Sci. 336, 283 (2011)]. As a tool for measuring the properties of low-density plasmas, the system is applicable for the measurements of the electron temperature and density in collisionless shock experiments [Y. Kuramitsu et al., Phys. Rev. Lett. 106, 175002 (2011)].

Morita, T.; Sakawa, Y.; Kuramitsu, Y.; Sano, T.; Takabe, H. [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan); Dono, S.; Ide, T.; Tanji, H.; Shiroshita, A. [Graduate School of Engineering, Osaka University, 1-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Shibata, S.; Aoki, H. [Graduate School of Science, Osaka University, 1-1 Machikane-yama, Toyonaka, Osaka 560-0043 (Japan); Waugh, J. N.; Woolsey, N. C. [Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom); Gregory, C. D. [LULI, Ecole Polytechnique, CNRS, CEA, UPMC, Route de Saclay, 91128 Palaiseau (France)

2012-10-15T23:59:59.000Z

338

Oxide Target Designs for High Primary Beam Intensities for Future Radioactive Ion Beam Facilities  

SciTech Connect

Oxide targets used nowadays in ISOL facilities can only accommodate up to a few kW incoming beam power because of the targets' moderate operation temperatures and their low thermal conductivities. A generic design to accommodate a 100 kW, 1 GeV proton beam, used as baseline parameters in the ongoing EURISOL-DS project, along with the numerical and experimental tools required for its validation, are reported here. We provide some details on these high-power composite oxide-refractory metal targets and on the proposed arrangement in several sub-units merging into a single ion source.

Stora, T.; Bouquerel, E.; Bruno, L.; Catherall, R.; Fernandes, S.; Kasprowicz, P.; Lettry, J.; Marzari, S.; Noah, E.; Penescu, L.; Wilfinger, R. [AB Department, CERN, CH-1211 Geneva 23 (Switzerland); Singh, B. S. Nara [Department of Physics, University of York, York, Y10 5DD (United Kingdom)

2009-03-10T23:59:59.000Z

339

Contribution to the numerical study of turbulence in high intensity discharge lamps  

SciTech Connect

We present in this paper a comparison between results obtained with a laminar and turbulent models for high-pressure mercury arc. The two models are based on the resolution of bidimensional time-dependent equations by a semi-implicit finite-element code. The numerical computation of turbulent model is solved with large eddy simulation model; this approach takes into account the various scales of turbulence by a filtering method on each scale. The results show the quantitative influence of turbulence on the flow fields and also the difference between laminar and turbulent effects on the dynamic thermal behaviour and on the characteristics of the discharge.

Kaziz, S.; Ben Ahmed, R.; Helali, H.; Gazzah, H.; Charrada, K. [Unite d'Etude des Milieux Ionises et Reactifs, IPEIM, 5019 route de Kairouan Monastir (Tunisia)

2011-07-15T23:59:59.000Z

340

LambdaStation: Exploiting Advance Networks In Data Intensive High Energy Physics Applications  

SciTech Connect

Lambda Station software implements selective, dynamic, secure path control between local storage & analysis facilities, and high bandwidth, wide-area networks (WANs). It is intended to facilitate use of desirable, alternate wide area network paths which may only be intermittently available, or subject to policies that restrict usage to specified traffic. Lambda Station clients gain awareness of potential alternate network paths via Clarens-based web services, including path characteristics such as bandwidth and availability. If alternate path setup is requested and granted, Lambda Station will configure the local network infrastructure to properly forward designated data flows via the alternate path. A fully functional implementation of Lambda Station, capable of dynamic alternate WAN path setup and teardown, has been successfully developed. A limited Lambda Station-awareness capability within the Storage Resource Manager (SRM) product has been developed. Lambda Station has been successfully tested in a number of venues, including Super Computing 2008. LambdaStation software, developed by the Fermilab team, enables dynamic allocation of alternate network paths for high impact traffic and to forward designated flows across LAN. It negotiates with reservation and provisioning systems of WAN control planes, be it based on SONET channels, demand tunnels, or dynamic circuit networks. It creates End-To-End circuit between single hosts, computer farms or networks with predictable performance characteristics, preserving QoS if supported in LAN and WAN and tied security policy allowing only specific traffic to be forwarded or received through created path. Lambda Station project also explores Network Awareness capabilities.

Harvey B. Newman

2009-09-11T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" from the National Library of EnergyBeta (NLEBeta).
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341

Pulsed laser ablation plasmas generated in CO{sub 2} under high-pressure conditions up to supercritical fluid  

Science Conference Proceedings (OSTI)

Pulsed laser ablation of solids in supercritical media has a large potential for nanomaterials fabrication. We investigated plasmas generated by pulsed laser ablation of Ni targets in CO{sub 2} at pressures ranging from 0.1 to 16 MPa at 304.5 K. Plasma species were characterized by optical emission spectroscopy, and the evolution of cavitation bubbles and shockwaves were observed by time-resolved shadowgraph imaging. Ni and O atomic emissions decreased with increasing gas pressure; however, near the critical point the intensities reached local maxima, probably due to the enhancement of the plasma excitation and effective quenching resulting from the large density fluctuation.

Kato, Toru; Stauss, Sven; Kato, Satoshi; Urabe, Keiichiro; Terashima, Kazuo [Department of Advanced Materials Science, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Baba, Motoyoshi; Suemoto, Tohru [Division of Advanced Spectroscopy, Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan)

2012-11-26T23:59:59.000Z

342

High-intensity discharge (HID) solid-state ballast program: engineering development report. Phase II  

SciTech Connect

A high frequency (28 to 31/sup 0/K Hz) electronic current source (ballast) designed to drive a 200 watt 100 volt sodium vapor gas discharge lamp is described. A resonant switching power amplifier system utilizing a novel constant power feedback loop is employed to maintain the lamp input power constant within two percent via changes due to lamp aging etc. The lamp input power and therefore the light output is adjustable from 50 to 100 percent of rated power. A input (electronic filter) inverter, changes the 277 volts alternating voltage input to a regulated direct current (DC) voltage used to power the output stage. The inverter reflects, a essentially unity power factor load to the power input source at all times.

Carlson, R.S.

1983-12-01T23:59:59.000Z

343

Design features of high-intensity medium-energy superconducting heavy-ion Linac.  

DOE Green Energy (OSTI)

The proposed Rare Isotope Accelerator (RIA) requires the construction of a cw 1.4 GV superconducting (SC) linac that is capable of producing 400 kW beams of all ions from protons at 900 MeV to uranium at 400 MeV/u. The design of such a linac was outlined at the previous Linac conference. This linac will accelerate multiple-charge-states (multi-q) of the heaviest ion beams, for which the beam current is limited by ion-source performance. The linac consists of two different types of accelerating and focusing lattice: for uranium below {approx}85 MeV/u the focusing is provided by SC solenoids installed in cryostats with the SC resonators while in the high-beta section the focusing elements are located outside of the cryostats. A detailed design has been developed for the focusing-accelerating lattice of the linac. Beam dynamics studies have been performed with the goal of optimization of the linac structure in order to reduce a possible effective emittance growth of the multi-q uranium beam. A wide tuning range of the accelerating and focusing fields is required for acceleration of the variety of ions with different charge-to-mass ratios to the highest possible energy in single charge state mode. The focusing must be retuned for different ion masses to avoid resonance coupling between the transverse and longitudinal motions. Any visible impact of this coupling on the formation of beam halo must be avoided due to the high beam power.

Ostroumov, P. N.

2002-09-20T23:59:59.000Z

344

Consequences of intensity constraints on inertial confinement fusion  

SciTech Connect

It is shown that the conflicting requirements of high implosion efficiency (low corona temperature) and adequate energy transport (high corona temperature) can, together with other effects, limit useful infrared light intensities to values on the order of 100 Tw/cm/sup 2/. Increased interest in ultraviolet lasers, for which this intensity constraint is expected to be less severe, and the entry of charged-particle drivers in the inertial confinement fusion (ICF) competition are consequences of this limitation. Analytical results based on a simple model are presented which show how the gain of an ICF target is modified by the existence of an arbitrary intensity constraint.

Kidder, R.E.

1979-09-13T23:59:59.000Z

345

Study of second harmonic generation by high power laser beam in magneto plasma  

SciTech Connect

This paper examines the problem of nonlinear generation of second harmonic of a high power laser pulse propagating in magnetized plasma. The propagation of strong laser beam is proposed in the direction perpendicular to a relatively weak static magnetic field. The laser pulse is taken to be linearly polarized, with the orientation of its electric field that corresponds to an ordinary electromagnetic wave. Besides the standard ponderomotive nonlinearity, the appropriate wave equation also contains the nonlinearity that arises from the relativistic electron jitter velocities. During its propagation, the laser beam gets filamented on account of relativistic and pondermotive nonlinearities present in the plasma. The generated plasma wave gets coupled into the filamentary structures of the pump beam. Due to the expected presence of the beam filamentation, the work has been carried out by considering modified paraxial approximation (i.e., beyond the standard paraxial approximation of a very broad beam). It is found that the power of the plasma wave is significantly affected by the magnetic field strength in the presence of both relativistic and pondermotive nonlinearities. It is investigated that the second harmonic generation is also considerably modified by altering the strength of magnetic field. To see the effect of static magnetic field on the harmonic generation, a key parameter, i.e., the ratio of the cyclotron frequency {omega}{sub c}=eB{sub 0}/mc over the laser frequency {omega}{sub 0} has been used, where c is the velocity of light, m and e are the mass and charge of the electron and B{sub 0} is the externally applied magnetic field.

Sharma, Prerana [Ujjain Engineering College, Ujjain, Madhya Pradesh 465010 (India); Sharma, R. P. [Centre for Energy Studies, Indian Institute of Technology, New Delhi 110016 (India)

2012-12-15T23:59:59.000Z

346

Applications of Nd:YAG laser micromanufacturing in High Temperature Gas Reactor research  

SciTech Connect

Two innovative applications of Nd:YAG laser micromachining techniques are demonstrated in this publication. Research projects to determine the fission product transport mechanisms in TRISO coated particles necessitate heat treatment studies as well as the manufacturing of a unique sealed system for experimentation at very high temperatures. This article describes firstly the design and creation of an alumina jig designed to contain 500 {mu}m diameter ZrO2 spheres intended for annealing experiments at temperatures up to 1600 C. Functional requirements of this jig are the precision positioning of spheres for laser ablation, welding and post weld heat treatment in order to ensure process repeatability and accurate indexing of individual spheres. The design challenges and the performance of the holding device are reported. Secondly the manufacture of a sealing system using laser micromachining is reported. ZrO2 micro plugs isolate the openings of micro-machined cavities to produce a gas-tight seal fit for application in a high temperature environment. The technique is described along with a discussion of the problems experienced during the sealing process. Typical problems experienced were seating dimensions and the relative small size ({approx} 200 {mu}m) of these plugs that posed handling challenges. Manufacturing processes for both the tapered seating cavity and the plug are demonstrated. In conclusion, this article demonstrates the application of Nd-YAG micromachining in an innovative way to solve practical research problems.

I. J. van Rooyen; C. A. Smal; J. Steyn; H. Greyling

2012-08-01T23:59:59.000Z

347

D&D Toolbox Robotic Deployment of High Resolution Laser Imaging for Characterization  

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

Tech Stage: Demonstration D&D Toolbox: Project OR-071203, OR-071303; Deployed at SRS P Reactor Area Closure Project PBS SR-0040 The robotically deployed laser surveying system was demonstrated in the Purification room of SRS P-Reactor on September 24, 2008. Page 1 of 2 Savannah River Site South Carolina Michigan D&D Toolbox Robotic Deployment of High Resolution Laser Imaging for Characterization Challenge The characterization of complex and/or hazardous facilities for the purposes of planning D&D projects can be excessively time consuming and present unacceptable hazards for personnel who enter or access the facility. Planners must know the condition of facilities which may have been abandoned in years past with little or no

348

High passive-stability diode-laser design for use in atomic-physics experiments  

E-Print Network (OSTI)

We present the design and performance characterization of an external cavity diode-laser system optimized for high stability, low passive spectral linewidth, low cost, and ease of in-house assembly. The main cavity body is machined from a single aluminum block for robustness to temperature changes and mechanical vibrations, and features a stiff and light diffraction-grating arm to suppress low-frequency mechanical resonances. The cavity is vacuum-sealed, and a custom-molded silicone external housing further isolates the system from acoustic noise and temperature fluctuations. Beam shaping, optical isolation, and fiber coupling are integrated, and the design is easily adapted to many commonly used wavelengths. Resonance data, passive-linewidth data, and passive stability characterization of the new design demonstrate that its performance exceeds published specifications for commercial precision diode-laser systems. The design is fully documented and freely available.

Cook, Eryn C; Brown-Heft, Tobias L; Garman, Jeffrey C; Steck, Daniel A

2012-01-01T23:59:59.000Z

349

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

350

Method and apparatus for reducing diffraction-induced damage in high power laser amplifier systems  

DOE Patents (OSTI)

Self-focusing damage caused by diffraction in laser amplifier systems may be minimized by appropriately tailoring the input optical beam profile by passing the beam through an aperture having a uniform high optical transmission within a particular radius r.sub.o and a transmission which drops gradually to a low value at greater radii. Apertures having the desired transmission characteristics may readily be manufactured by exposing high resolution photographic films and plates to a diffuse, disk-shaped light source and mask arrangement.

Campillo, Anthony J. (Los Alamos, NM); Newnam, Brian E. (Los Alamos, NM); Shapiro, Stanley L. (Los Alamos, NM); Terrell, Jr., N. James (Los Alamos, NM)

1976-01-01T23:59:59.000Z

351

Power Beamed Photon Sails: New Capabilities Resulting From Recent Maturation Of Key Solar Sail And High Power Laser Technologies  

SciTech Connect

This paper revisits some content in the First International Symposium on Beamed Energy Propulsion in 2002 related to the concept of propellantless in-space propulsion utilizing an external high energy laser to provide momentum to an ultralightweight (gossamer) spacecraft. The design and construction of the NanoSail-D solar sail demonstration spacecraft has demonstrated in space flight hardware the concept of small, very light--yet capable--spacecraft. The results of the Joint High Power Solid State Laser (JHPSSL) have also increased the effectiveness and reduced the cost of an entry level laser source. This paper identifies the impact from improved system parameters on current mission applications.

Montgomery, Edward E. IV [United States Army Space and Missile Defense Command, Huntsville, Alabama (United States)

2010-05-06T23:59:59.000Z

352

Assessment of Electrical, Efficiency, and Photometric Performance of Advanced Lighting Sources: Dimmable Advanced Lighting Technolog ies -- Electronic High-Intensity Discharge Ballasts  

Science Conference Proceedings (OSTI)

This EPRI Technical Update addresses the dimming performance of electronic high-intensity discharge (HID) ballasts. Chapter 1 provides a discussion of basic lighting control, the importance of considering power quality in lighting control, lighting control methods and parameters, and the advantages and future of lighting control. Chapter 2 addresses in more depth the dimming methods used in advanced lighting sources and controls for incandescent, fluorescent, high-intensity discharge (HID) and light-emit...

2008-12-18T23:59:59.000Z

353

Nonlinear propagation of a high-power focused femtosecond laser pulse in air under atmospheric and reduced pressure  

Science Conference Proceedings (OSTI)

This paper examines the propagation of focused femtosecond gigawatt laser pulses in air under normal and reduced pressure in the case of Kerr self-focusing and photoionisation of the medium. The influence of gas density on the beam dimensions and power and the electron density in the plasma column in the nonlinear focus zone of the laser beam has been studied experimentally and by numerical simulation. It has been shown that, in rarefied air, the radiation-induced reduction in the rate of plasma formation diminishes the blocking effect of the plasma on the growth of the beam intensity in the case of tight focusing. This allows higher power densities of ultrashort laser pulses to be reached in the focal waist region in comparison with beam self-focusing under atmospheric pressure.

Geints, Yu E; Zemlyanov, A A; Ionin, Andrei A; Kudryashov, Sergei I; Seleznev, L V; Sinitsyn, D V; Sunchugasheva, E S

2012-04-30T23:59:59.000Z

354

Particle physics with a laser-driven positronium atom  

E-Print Network (OSTI)

A detailed quantum-electrodynamic calculation of muon pair creation in laser-driven electron-positron collisions is presented. The colliding particles stem from a positronium atom exposed to a superintense laser wave of linear polarization, which allows for high luminosity. The threshold laser intensity of this high-energy reaction amounts to a few 10^22 W/cm^2 in the near-infrared frequency range. The muons produced form an ultrarelativistic, strongly collimated beam, which is explicable in terms of a classical simple-man's model. Our results indicate that the process can be observed at high positronium densities with the help of present-day laser technology.

Carsten Müller; Karen Z. Hatsagortsyan; Christoph H. Keitel

2007-05-07T23:59:59.000Z

355

Laser Beam Delivery [Laser Applications Laboratory] - Nuclear...  

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

Laser Glazing of Railroad Rails High Power Laser Beam Delivery Decontamination and Decommissioning Refractory Alloy Welding Robots Applications Other Facilities Other Capabilities...

356

Searching for optimal mitigation geometries for laser resistant multilayer high reflector coatings  

SciTech Connect

Growing laser damage sites on multilayer high reflector coatings can limit mirror performance. One of the strategies to improve laser damage resistance is to replace the growing damage sites with pre-designed benign mitigation structures. By mitigating the weakest site on the optic, the large aperture mirror will have a laser resistance comparable to the intrinsic value of the multilayer coating. To determine the optimal mitigation geometry, the finite difference time domain method (FDTD) was used to quantify the electric-field intensification within the multilayer, at the presence of different conical pits. We find that the field intensification induced by the mitigation pit is strongly dependent on the polarization and the angle of incidence (AOI) of the incoming wave. Therefore the optimal mitigation conical pit geometry is application specific. Furthermore, our simulation also illustrates an alternative means to achieve an optimal mitigation structure by matching the cone angle of the structure with the AOI of the incoming wave, except for the p-polarization wave at a range of incident angles between 30{sup o} and 45{sup o}.

Qiu, S R; Wolfe, J E; Monterrosa, A M; Feit, M D; Pistor, T V; STolz, C J

2011-02-11T23:59:59.000Z

357

Guest Editorial: Laser Damage  

SciTech Connect

Laser damage of optical materials, first reported in 1964, continues to limit the output energy and power of pulsed and continuous-wave laser systems. In spite of some 48 years of research in this area, interest from the international laser community to laser damage issues remains at a very high level and does not show any sign of decreasing. Moreover, it grows with the development of novel laser systems, for example, ultrafast and short-wavelength lasers that involve new damage effects and specific mechanisms not studied before. This interest is evident from the high level of attendance and presentations at the annual SPIE Laser Damage Symposium (aka, Boulder Damage Symposium) that has been held in Boulder, Colorado, since 1969. This special section of Optical Engineering is the first one devoted to the entire field of laser damage rather than to a specific part. It is prepared in response to growing interest from the international laser-damage community. Some papers in this special section were presented at the Laser Damage Symposium; others were submitted in response to the general call for papers for this special section. The 18 papers compiled into this special section represent many sides of the broad field of laser-damage research. They consider theoretical studies of the fundamental mechanisms of laser damage including laser-driven electron dynamics in solids (O. Brenk and B. Rethfeld; A. Nikiforov, A. Epifanov, and S. Garnov; T. Apostolova et al.), modeling of propagation effects for ultrashort high-intensity laser pulses (J. Gulley), an overview of mechanisms of inclusion-induced damage (M. Koldunov and A. Manenkov), the formation of specific periodic ripples on a metal surface by femtosecond laser pulses (M. Ahsan and M. Lee), and the laser-plasma effects on damage in glass (Y. Li et al). Material characterization is represented by the papers devoted to accurate and reliable measurements of absorption with special emphasis on thin films (C. Mühlig and S. Bublitz; B. Cho, E. Danielewicz, and J. Rudisill; W. Palm et al; and J. Lu et al.). Statistical treatment of measurements of the laser-damage threshold (J. Arenberg) and the relationship to damage mechanisms (F. Wagner et al.) represent the large subfield of laser-damage measurements. Various aspects of multilayer coating and thin-film characterization are considered in papers by B. Cho, J. Rudisill, and E. Danielewicz (spectral shift in multilayer mirrors) and R. Weber et al. (novel approach to damage studies based on third-harmonic generation microscopy). Of special interest for readers is the paper by C. Stolz that summarizes the results of four “thin-film damage competitions” organized as a part of the Laser Damage Symposium. Another paper is devoted to thermal annealing of damage precursors (N. Shen et al.). Finally, the influence of nano-size contamination on initiation of laser damage by ultrashort pulses is considered in paper of V. Komolov et al.

Vitaly Gruzdev, Michelle D. Shinn

2012-12-01T23:59:59.000Z

358

Preformed transient gas channels for laser wakefield particle acceleration  

SciTech Connect

Acceleration of electrons by laser-driven plasma wake fields is limited by the range over which a laser pulse can maintain its intensity. This distance is typically given by the Rayleigh range for the focused laser beam, usually on the order of 0.1 mm to 1 mm. For practical particle acceleration, interaction distances on the order of centimeters are required. Therefore, some means of guiding high intensity laser pulses is necessary. Light intensities on the order of a few times 10{sup 17} W/cm{sup 2} are required for laser wakefield acceleration schemes using near IR radiation. Gas densities on the order of or greater than 10{sup 17} cm{sup {minus}3} are also needed. Laser-atom interaction studies in this density and intensity regime are generally limited by the concomitant problems in beam propagation introduced by the creation of a plasma. In addition to the interaction distance limit imposed by the Rayleigh range, defocusing of the high intensity laser pulse further limits the peak intensity which can be achieved. To solve the problem of beam propagation limitations in laser-plasma wakefield experiments, two potential methods for creating transient propagation channels in gaseous targets are investigated. The first involves creation of a charge-neutral channel in a gas by an initial laser pulse, which then is ionized by a second, ultrashort, high-intensity pulse to create a waveguide. The second method involves the ionization of a gas column by an ultrashort pulse; a transient waveguide is formed by the subsequent expansion of the heated plasma into the neutral gas.

Wood, W.M.

1994-11-01T23:59:59.000Z

359

HIGH LATITUDE ULYSSES OBSERVATIONS OF THE H/HE INTENSITY RATIO UNDER SOLAR MINIMUM AND SOLAR MAXIMUM CONDITIONS  

DOE Green Energy (OSTI)

We analyze measurements of the 0.5-1.0 MeV/nucleon H/He intensity ratio from the Ulysses spacecraft during its first (1992-94) and second (1999-2000) ascent to southern high latitude regions of the heliosphere. These cover a broad range of heliocentric distances (from 5.2 to 2.0 AU) and out-of-ecliptic latitudes (from 18{degree}S to 80{degree}S). During Ulysses' first southern pass, the HI-SCALE instrument measured a series of enhanced particle fluxes associated with the passage of a recurrent corotating interaction region (CIR). Low values ({approximately}6) of the H/He ratio were observed in these recurrent corotating events, with a clear minimum following the passage of the corotating reverse shock. When Ulysses reached high southern latitudes (>40{degree}S), the H/He ratio always remained below {approximately}10 except during two transient solar events that brought the ratio to high (>20) values. Ulysses' second southern pass was characterized by a higher average value of the H/He ratio. No recurrent pattern was observed in the energetic ion intensity which was dominated by the occurrence of transient events of solar origin. Numerous CIRs, many of which were bounded by forward and reverse shock pairs, were still observed in the solar wind and magnetic field data. The arrival of those CIRs at Ulysses did not always result in a decrease of the H/He ratio; on the contrary, many CIRs showed a higher H/He ratio than some transient events. Within a CIR, however, the H/He ratio usually increased around the forward shock and decreased towards the reverse shock. Throughout the second ascent to southern heliolatitudes, the H/He ratio seldom decreased below {approximately}10 even at high latitudes (>40{degree}S). We interpret these higher values of the H/He ratio in terms of the increasing level of solar activity together with the poor definition and short life that corotating solar wind structures have under solar maximum conditions. The global filling of the heliosphere by transient solar events and the fact that in 1999-2000 Ulysses observed only intermediate (<650 km s{sup {minus}1}) solar wind speed (whose contents in pick-up He is less energetic than in the fast solar wind streams observed in 1992-1994) favored the protons with respect to alpha particles. Hence the fact that the average values of the H/He ratio observed by Ulysses during the rising phase of the solar cycle (1999-2000) were higher than those observed during the declining phase (1992-1994).

J. GOSLING; D. LARIO; ET AL

2001-03-01T23:59:59.000Z

360

Laser driven quasi-isentropic compression experiments (ICE) for dynamically loading materials at high strain rates  

Science Conference Proceedings (OSTI)

We demonstrate the recently developed technique of laser driven isentropic compression (ICE) for dynamically compressing Al samples at high loading rates close to the room temperature isentrope and up to peak stresses above 100GPa. Upon analysis of the unloading profiles from a multi-stepped Al/LiF target a continuous path through Stress-Density space may be calculated. For materials with phase transformations ramp compression techniques reveals the location of equilibrium phase boundaries and provide information on the kinetics of the lattice re-ordering.

Smith, R; Eggert, J; Celliers, P; Jankowski, A; Lorenz, T; Moon, S; Edwards, M J; Collins, G

2006-03-30T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" 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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to obtain the most current and comprehensive results.


361

Observation of Synchrotron Radiation from Electrons Accelerated in a Petawatt-Laser-Generated Plasma Cavity  

Science Conference Proceedings (OSTI)

The dynamics of plasma electrons in the focus of a petawatt laser beam are studied via measurements of their x-ray synchrotron radiation. With increasing laser intensity, a forward directed beam of x rays extending to 50 keV is observed. The measured x rays are well described in the synchrotron asymptotic limit of electrons oscillating in a plasma channel. The critical energy of the measured synchrotron spectrum is found to scale as the Maxwellian temperature of the simultaneously measured electron spectra. At low laser intensity transverse oscillations are negligible as the electrons are predominantly accelerated axially by the laser generated wakefield. At high laser intensity, electrons are directly accelerated by the laser and enter a highly radiative regime with up to 5% of their energy converted into x rays.

Kneip, S.; Nagel, S. R.; Bellei, C.; Dangor, A. E.; Mangles, S. P. D.; Nilson, P. M.; Willingale, L.; Najmudin, Z. [Blackett Laboratory, Imperial College London SW7 2AZ (United Kingdom); Bourgeois, N.; Marques, J. R. [Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, 91128 Palaiseau (France); Gopal, A. [Department of Electronics, Technological Educational Institute of Crete, Romanou, 3-GR73133 Chania (Greece); Heathcote, R. [Central Laser Facility, Rutherford Appleton Laboratory, Oxon OX11 0QX (United Kingdom); Maksimchuk, A.; Reed, S. [Center for Ultrafast Optical Science (CUOS) University of Michigan, Ann Arbor, Michigan 48109 (United States); Phuoc, K. Ta; Rousse, A. [Laboratoire d'Optique Applique, ENSTA, Ecole Polytechnique, 91761 Palaiseau (France); Tzoufras, M.; Tsung, F. S.; Mori, W. B. [Department of Physics and Astronomy and Department of Electrical Engineering, UCLA, Los Angeles, California 90095 (United States); Krushelnick, K. [Blackett Laboratory, Imperial College London SW7 2AZ (United Kingdom); Center for Ultrafast Optical Science (CUOS) University of Michigan, Ann Arbor, Michigan 48109 (United States)

2008-03-14T23:59:59.000Z

362

X-ray spectroscopy of buried layer foils irradiated with an ultra high intensity short pulse laser  

E-Print Network (OSTI)

The image plate, FujiFilm BAS-TR, was wrapped in 5 µm of Alwere read using the FujiFilm BAS-1800 II with 50 µm scanningThe image plate, FujiFilm BAS-MS, was fully enclosed 18 µm

Chen, Sophia Nan

2009-01-01T23:59:59.000Z

363

Synchronization of sub-picosecond electron and laser pulses  

SciTech Connect

Sub-picosecond laser-electron synchronization is required to take full advantage of the experimental possibilities arising from the marriage of modern high intensity lasers and high brightness electron beams in the same laboratory. Two particular scenarios stand out in this regard, injection of ultra-short electron pulses in short wavelength laser-driven plasma accelerators, and Compton scattering of laser photons from short electron pulses. Both of these applications demand synchronization, which is sub-picosecond, with tens of femtosecond synchronization implied for next generation experiments. The design of a microwave timing modulator system is now being investigated in more detail. (AIP) {copyright} {ital 1999 American Institute of Physics.}

Rosenzweig, J.B. [UCLA Department of Physics and Astronomy, 405 Hilgard Ave., Los Angeles, California 90095 (United States); Le Sage, G.P. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

1999-07-01T23:59:59.000Z

364

Synchronization of sub-picosecond electron and laser pulses  

SciTech Connect

Sub-picosecond laser-electron synchronization is required to take full advantage of the experimental possibilities arising from the marriage of modern high intensity lasers and high brightness electron beams in the same laboratory. Two particular scenarios stand out in this regard, injection of ultra-short electron pulses in short wavelength laser-driven plasma accelerators, and Compton scattering of laser photons from short electron pulses. Both of these applications demand synchronization, which is sub-picosecond, with tens of femtosecond synchronization implied for next generation experiments. The design of a microwave timing modulator system is now being investigated in more detail.

Rosenzweig, J. B.; Le Sage, G. P. [UCLA Department of Physics and Astronomy, 405 Hilgard Ave., Los Angeles, California 90095 (United States); Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

1999-07-12T23:59:59.000Z

365

Experimental setup for laser spectroscopy of molecules in a high magnetic field  

Science Conference Proceedings (OSTI)

An experimental setup to measure the effects of a high magnetic field on the structure and decay dynamics of molecules is designed and constructed. A vacuum chamber is mounted in the bore of a superconducting magnet. A molecular beam passes in the chamber. Pulsed laser light excites the molecules in the field. The parent or fragment ions are extracted by an electric field parallel to the magnetic field. They are detected by a microchannel plate. Their mass and charge are determined by the time-of-flight method. The performance of the setup was examined using resonance-enhanced two-photon ionization through the X 2 ? – A 2 ? + transition of nitric oxide (NO) molecules. The ions were detected with sufficient mass resolution to discriminate the species in a field of up to 10 T. This is the first experiment to succeed in the mass-selective detection of ions by the time-of-flight method in a high magnetic field. By measuring NO + ion current as a function of the laser frequency

Yasuyuki Kimura and Ken Takazawa

2011-01-01T23:59:59.000Z

366

High resolution laser spectroscopy of cesium and rubidium molecules with optically induced coherence  

E-Print Network (OSTI)

This work is devoted to the study of the quantum coherent effects in diatomic molecular systems by using high resolution laser spectroscopy. In particular, we have studied the rubidium diatomic molecular gaseous medium's absorption spectrum with high resolution single mode laser spectroscopy. The derived electronic and rotational vibrational constants were used in the backward Raman amplification experiment of Rb diatomic molecule. Both experimental results and theoretical calculation confirms that there is strong backward directionally dependent radiation. This effect can further be utilized in remote detection of chemical material. In the saturated spectroscopy experiment of the cesium diatomic molecule, long-lived ground state coherence was observed. The coherence would decay at a rate less than the natural life time of the excited states, which indicates great possibility for performing the quantum optics experiments previously performed in atomic systems only. Electromagnetically induced transparency has been observed in many atomic systems for many years, while it has been seldom realized in molecular systems. In our experiment of electromagnetically induced transparency in cesium diatomic molecules, we utilized Ă?Â? energy levels, and observed subnatural linewidth. This is the first time to realize a Ă?Â? type EIT in a molecular ensemble. This experiment will lead to many other experiments of quantum effects in a molecular system, such like magnetic optical rotation, light storage in ensemble of molecules. Magnetically induced chirality in an atomic ensemble is also investigated in my research.

Chen, Hui

2006-08-01T23:59:59.000Z

367

Chirped pulse inverse free-electron laser vacuum accelerator  

SciTech Connect

A chirped pulse inverse free-electron laser (IFEL) vacuum accelerator for high gradient laser acceleration in vacuum. By the use of an ultrashort (femtosecond), ultrahigh intensity chirped laser pulse both the IFEL interaction bandwidth and accelerating gradient are increased, thus yielding large gains in a compact system. In addition, the IFEL resonance condition can be maintained throughout the interaction region by using a chirped drive laser wave. In addition, diffraction can be alleviated by taking advantage of the laser optical bandwidth with negative dispersion focusing optics to produce a chromatic line focus. The combination of these features results in a compact, efficient vacuum laser accelerator which finds many applications including high energy physics, compact table-top laser accelerator for medical imaging and therapy, material science, and basic physics.

Hartemann, Frederic V. (Dublin, CA); Baldis, Hector A. (Pleasanton, CA); Landahl, Eric C. (Walnut Creek, CA)

2002-01-01T23:59:59.000Z

368

High energy bursts from a solid state laser operated in the heat capacity limited regime  

DOE Patents (OSTI)

Solid state laser technology is a very well developed field and numerous embodiments and modes of operation have been demonstrated. A more recent development has been the pumping of a solid state laser active medium with an array of diode lasers (diode pumping, for short). These diode pump packages have previously been developed to pump solid state lasers with good efficiency, but low average power. This invention is a method and the resulting apparatus for operating a solid state laser in the heat capacity mode. Instead of cooling the laser, the active medium will heat up until it reaches some maximum acceptable temperature. The waste heat is stored in the active medium itself.

Albrecht, G.; George, E.V.; Krupke, W. [and others

1994-12-31T23:59:59.000Z

369

Laser Systems for Orbital Debris Removal  

SciTech Connect

The use of a ground based laser for space debris cleaning was investigated by the ORION project in 1996. Since that study the greatest technological advance in the development of high energy pulsed laser systems has taken place within the NIF project at LLNL. The proposed next laser system to follow the NIF at LLNL will be a high rep rate version of the NIF based on diode-pumping rather than flashlamp excitation; the so called 'LIFE' laser system. Because a single 'LIFE' beamline could be built up in a few year time frame, and has performance characteristics relevant to the space debris clearing problem, such a beamline could enable a near term demonstration of space debris cleaning. Moreover, the specifics of debris cleaning make it possible to simplify the LIFE laser beyond what is required for a fusion drive laser, and so substantially reduce its cost. Starting with the requirements for laser intensity on the target, and then considering beam delivery, we will flow back the laser requirements needed for space debris cleaning. Using these derived requirements we will then optimize the pulse duration, the operational regime, and the output pulse energy of the laser with a focus of simplifying its overall design. Anticipated simplifications include operation in the heat capacity regime, eliminating cooling requirements on the laser gain slabs, and relaxing B-integral and birefrigence requirements.

Rubenchik, A M; Barty, C P; Beach, R J; Erlandson, A C; Caird, J A

2010-02-05T23:59:59.000Z

370

A Secure Web Application Providing Public Access to High-Performance Data Intensive Scientific Resources - ScalaBLAST Web Application  

SciTech Connect

This work presents the ScalaBLAST Web Application (SWA), a web based application implemented using the PHP script language, MySQL DBMS, and Apache web server under a GNU/Linux platform. SWA is an application built as part of the Data Intensive Computer for Complex Biological Systems (DICCBS) project at the Pacific Northwest National Laboratory (PNNL). SWA delivers accelerated throughput of bioinformatics analysis via high-performance computing through a convenient, easy-to-use web interface. This approach greatly enhances emerging fields of study in biology such as ontology-based homology, and multiple whole genome comparisons which, in the absence of a tool like SWA, require a heroic effort to overcome the computational bottleneck associated with genome analysis. The current version of SWA includes a user account management system, a web based user interface, and a backend process that generates the files necessary for the Internet scientific community to submit a ScalaBLAST parallel processing job on a dedicated cluster.

Curtis, Darren S.; Peterson, Elena S.; Oehmen, Chris S.

2008-05-04T23:59:59.000Z

371

MR-Guided High-Intensity Focused Ultrasound Ablation of Breast Cancer with a Dedicated Breast Platform  

SciTech Connect

Optimizing the treatment of breast cancer remains a major topic of interest. In current clinical practice, breast-conserving therapy is the standard of care for patients with localized breast cancer. Technological developments have fueled interest in less invasive breast cancer treatment. Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) is a completely noninvasive ablation technique. Focused beams of ultrasound are used for ablation of the target lesion without disrupting the skin and subcutaneous tissues in the beam path. MRI is an excellent imaging method for tumor targeting, treatment monitoring, and evaluation of treatment results. The combination of HIFU and MR imaging offers an opportunity for image-guided ablation of breast cancer. Previous studies of MR-HIFU in breast cancer patients reported a limited efficacy, which hampered the clinical translation of this technique. These prior studies were performed without an MR-HIFU system specifically developed for breast cancer treatment. In this article, a novel and dedicated MR-HIFU breast platform is presented. This system has been designed for safe and effective MR-HIFU ablation of breast cancer. Furthermore, both clinical and technical challenges are discussed, which have to be solved before MR-HIFU ablation of breast cancer can be implemented in routine clinical practice.

Merckel, Laura G., E-mail: L.G.Merckel-2@umcutrecht.nl [University Medical Center Utrecht, Department of Radiology (Netherlands); Bartels, Lambertus W., E-mail: W.Bartels@umcutrecht.nl [University Medical Center Utrecht, Image Sciences Institute (Netherlands); Koehler, Max O., E-mail: max.kohler@philips.com [Philips Healthcare (Finland); Bongard, H. J. G. Desiree van den, E-mail: D.vandenBongard@umcutrecht.nl [University Medical Center Utrecht, Department of Radiotherapy (Netherlands); Deckers, Roel, E-mail: R.Deckers-2@umcutrecht.nl [University Medical Center Utrecht, Image Sciences Institute (Netherlands)] [University Medical Center Utrecht, Image Sciences Institute (Netherlands); Mali, Willem P. Th. M., E-mail: W.Mali@umcutrecht.nl [University Medical Center Utrecht, Department of Radiology (Netherlands); Binkert, Christoph A., E-mail: Christoph.Binkert@ksw.ch [Cantonal Hospital Winterthur, Department of Radiology (Switzerland); Moonen, Chrit T., E-mail: C.Moonen@umcutrecht.nl [University Medical Center Utrecht, Image Sciences Institute (Netherlands); Gilhuijs, Kenneth G. A., E-mail: K.G.A.Gilhuijs@umcutrecht.nl; Bosch, Maurice A. A. J. van den, E-mail: mbosch@umcutrecht.nl [University Medical Center Utrecht, Department of Radiology (Netherlands)

2013-04-15T23:59:59.000Z

372

Dynamic T{sub 2}-mapping during magnetic resonance guided high intensity focused ultrasound ablation of bone marrow  

Science Conference Proceedings (OSTI)

Focal bone tumor treatments include amputation, limb-sparing surgical excision with bone reconstruction, and high-dose external-beam radiation therapy. Magnetic resonance guided high intensity focused ultrasound (MR-HIFU) is an effective non-invasive thermotherapy for palliative management of bone metastases pain. MR thermometry (MRT) measures the proton resonance frequency shift (PRFS) of water molecules and produces accurate (<1 Degree-Sign C) and dynamic (<5s) thermal maps in soft tissues. PRFS-MRT is ineffective in fatty tissues such as yellow bone marrow and, since accurate temperature measurements are required in the bone to ensure adequate thermal dose, MR-HIFU is not indicated for primary bone tumor treatments. Magnetic relaxation times are sensitive to lipid temperature and we hypothesize that bone marrow temperature can be determined accurately by measuring changes in T{sub 2}, since T{sub 2} increases linearly in fat during heating. T{sub 2}-mapping using dual echo times during a dynamic turbo spin-echo pulse sequence enabled rapid measurement of T{sub 2}. Calibration of T{sub 2}-based thermal maps involved heating the marrow in a bovine femur and simultaneously measuring T{sub 2} and temperature with a thermocouple. A positive T{sub 2} temperature dependence in bone marrow of 20 ms/ Degree-Sign C was observed. Dynamic T{sub 2}-mapping should enable accurate temperature monitoring during MR-HIFU treatment of bone marrow and shows promise for improving the safety and reducing the invasiveness of pediatric bone tumor treatments.

Waspe, Adam C.; Looi, Thomas; Mougenot, Charles; Amaral, Joao; Temple, Michael; Sivaloganathan, Siv; Drake, James M. [Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada); Philips Healthcare Canada, Markham, ON, L6C 2S3 (Canada); Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada); Department of Applied Mathematics, University of Waterloo, Waterloo, ON, N2L 3G1 (Canada); Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada)

2012-11-28T23:59:59.000Z

373

Relativistic Laser Plasma Research for Fast Ignition Laser Fusion  

E-Print Network (OSTI)

Reviewed are the present status and future prospects of the laser fusion research at the ILE (Institute of Laser Engineering) Osaka. The Gekko XII and Peta Watt laser system have been operated for investigating the fast ignition, the relativistic laser plasma interactions and so on. In particular, the fast ignition experiments with cone shell target have been in progress as the UK and US-Japan collaboration programs. In the experiments, the imploded high density plasmas are heated by irradiating 500 J level peta watt laser pulse. The thermal neutron yield is found to increase by three orders of magnitude by injecting the peta watt laser into the cone shell target. Transport of relativistic high density electron is the critical issue as the basic physics for understanding the dense plasma heating process. By the theory, simulation and experiment, the collective phenomena in the interactions of intense relativistic electron current with dense plasmas has been investigated to find the formation of self organized flow as the result of filamentation (Weibel) instability. Through the present understanding, the new project, FIREX-I has started recently to prove the principle of the fast ignition scheme. Keywords: fast ignition, peta watt laser, relativistic electron, weibel instability

Mima Kunioki; Tanaka Kazuo. A; Kodama Ryosuke; Johzaki Tomohiro; Nagatomo Hideo; Shiraga Hiroyuki; Miyanaga Noriaki; Azechi Hiroshi; Nakai Mitsuo; Norimatsu Takayoshi; Nagai Keiji; Sunahara Atsushi; Nishihara Katsunobu; Taguchi Toshihiro; Sakagami Hitoshi; Sentoku Yasuhiko; Ruhl Hartmut

2003-01-01T23:59:59.000Z

374

Laser Welding of Metals [Laser Applications Laboratory] - Nuclear  

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

Laser Welding of Metals Laser Welding of Metals Capabilities Engineering Experimentation Reactor Safety Experimentation Aerosol Experiments System Components Laser Applications Overview Laser Oil & Gas Well Drilling Laser Heat Treatment Laser Welding of Metals On-line Monitoring Laser Beam Delivery Laser Glazing of Railroad Rails High Power Laser Beam Delivery Decontamination and Decommissioning Refractory Alloy Welding Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Laser Applications Laboratory Laser Welding of Metals Project description: High-speed laser welding of metals. Category: Project with industrial partner (Delphi Energy and Engine Management Systems) Bookmark and Share

375

Fusion pumped laser  

DOE Patents (OSTI)

The apparatus of this invention may comprise a system for generating laser radiation from a high-energy neutron source. The neutron source is a tokamak fusion reactor generating a long pulse of high-energy neutrons and having a temperature and magnetic field effective to generate a neutron flux of at least 10/sup 15/ neutrons/cm/sup 2//center dot/s. Conversion means are provided adjacent the fusion reactor at a location operable for converting the high-energy neutrons to an energy source with an intensity and energy effective to excite a preselected lasing medium. A lasing medium is spaced about and responsive to the energy source to generate a population inversion effective to support laser oscillations for generating output radiation. 2 figs., 2 tabs.

Pappas, D.S.

1987-07-31T23:59:59.000Z

376

Preparations for a high gradient inverse free electron laser experiment at Brookhaven national laboratory  

SciTech Connect

Preparations for an inverse free electron laser experiment at Brookhaven National Laboratory's Accelerator Test Facilty are presented. Details of the experimental setup including beam and laser transport optics are first discussed. Next, the driving laser pulse structure is investigated and initial diagnostics are explored and compared to simulations. Finally, planned improvements to the experimental setup are discussed.

Duris, J.; Li, R. K.; Musumeci, P.; Sakai, Y.; Threlkeld, E.; Williams, O.; Fedurin, M.; Kusche, K.; Pogorelsky, I.; Polyanskiy, M.; Yakimenko, V. [UCLA Department of Physics and Astronomy, Los Angeles, CA 90095 (United States); Accelerator Test Facility, Brookhaven National Laboratory, Upton, NY, 11973 (United States)

2012-12-21T23:59:59.000Z

377

Magnetic reconnection in high-energy-density laser-produced plasmas  

SciTech Connect

Recently, novel experiments on magnetic reconnection have been conducted in laser-produced plasmas in a high-energy-density regime. Individual plasma bubbles self-generate toroidal, mega-gauss-scale magnetic fields through the Biermann battery effect. When multiple bubbles are created at small separation, they expand into one another, driving reconnection of this field. Reconnection in the experiments was reported to be much faster than allowed by both Sweet-Parker, and even Hall-MHD theories, when normalized to the nominal magnetic fields self-generated by single bubbles. Through particle-in-cell simulations (both with and without a binary collision operator), we model the bubble interaction at parameters and geometry relevant to the experiments. This paper discusses in detail the reconnection regime of the laser-driven experiments and reports the qualitative features of simulations. We find substantial flux-pileup effects, which boost the relevant magnetic field for reconnection in the current sheet. When this is accounted for, the normalized reconnection rates are much more in line with standard two-fluid theory of reconnection. At the largest system sizes, we additionally find that the current sheet is prone to breakup into plasmoids.

Fox, W.; Bhattacharjee, A.; Germaschewski, K. [Center for Integrated Computation and Analysis of Reconnection and Turbulence, and Center for Magnetic Self-Organization in Laboratory and Astrophysical Plasmas, University of New Hampshire, Durham, New Hampshire 03824 (United States)

2012-05-15T23:59:59.000Z

378

Free electron lasers  

SciTech Connect

A review of experimental and theoretical concepts of a free electron laser is given. The possibilities of scaling these lasers to high powers are discussed. (MOW)

Brau, C.A.

1980-01-01T23:59:59.000Z

379

Advanced Laser Diagnostics Development for the Characterization of Gaseous High Speed Flows  

E-Print Network (OSTI)

The study of high-speed flows represents a challenging problem in the fluid dynamics field due to the presence of chemical reactions and non-equilibrium effects. Hypersonic flights, where speeds reach Mach 5 and above, are particularly influenced by these effects, resulting in a direct impact on the flow and consequently on the aerodynamic performance of a vehicle traveling at these speeds. The study of hypersonic flow conditions requires the experimental capability of determining local temperatures, pressures and velocities using non-intrusive techniques. Furthermore, the simultaneous measurement of two or more variables in a complex flow boosts the amount of information that is obtained since valuable correlations can be established. This research includes the design, construction and characterization of a hypersonic flow apparatus explicitly intended as a tool for advanced laser diagnostics development. This apparatus is characterized by its pulsed operation mode that translates into a significant reduction in mass flow rates and can be operated for long periods at Mach numbers ranging from 2.8 to 6.2. The flow conditions during the uniform flow time interval of each pulse vary by less than 1%, generating a flow of sufficient quality for quantitative measurements. The development of a laser diagnostic technique, the VENOM technique, which is a non-intrusive method to provide simultaneous 2-D measurements of the mean and instantaneous fluctuations in two-component velocity and temperature is also presented. This technique represents the first single diagnostic capable of instantaneous two-component velocimetry and thermometry in a gaseous flow field by combining two Nitric Oxide Planar Laser Induced Fluorescence methods: two-component Molecular Tagging Velocimetry and two-line thermometry, employing the nascent NO(v"=1) arising from the NO2 photodissociation as a molecular tracer. The VENOM technique is expected to be not only applicable to cold high-speed flows, which is the focus of the present work, but also to combustion and other reactive or high-enthalpy flow fields.

Sanchez-Gonzalez, Rodrigo

2012-05-01T23:59:59.000Z

380

Zig Zag Nd Laser - Industrial Partnerships Office  

The Laser Systems Group at LLNL has developed a high energy, high average power solid state laser system capable of performing production rate laser shot peening.

Note: This page contains sample records for the topic "high intensity laser" 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

Correlated-Intensity velocimeter for Arbitrary Reflector  

SciTech Connect

A velocimetry apparatus and method comprising splitting incoming reflected laser light and directing the laser light into first and second arms, filtering the laser light with passband filters in the first and second arms, one having a positive passband slope and the other having a negative passband slope, and detecting the filtered laser light via light intensity detectors following the passband filters in the first and second arms

Wang, Zhehui (Los Alamos, NM); Luo, Shengnian (Los Alamos, NM); Barnes, Cris W. (Arlington, VA); Paul, Stephen F. (West Orange, NJ)

2008-11-11T23:59:59.000Z

382

CO{sub 2} laser pulse shortening by laser ablation of a metal target  

Science Conference Proceedings (OSTI)

A repeatable and flexible technique for pulse shortening of laser pulses has been applied to transversely excited atmospheric (TEA) CO{sub 2} laser pulses. The technique involves focusing the laser output onto a highly reflective metal target so that plasma is formed, which then operates as a shutter due to strong laser absorption and scattering. Precise control of the focused laser intensity allows for timing of the shutter so that different temporal portions of the pulse can be reflected from the target surface before plasma formation occurs. This type of shutter enables one to reduce the pulse duration down to {approx}2 ns and to remove the low power, long duration tails that are present in TEA CO{sub 2} pulses. The transmitted energy is reduced as the pulse duration is decreased but the reflected power is {approx}10 MW for all pulse durations. A simple laser heating model verifies that the pulse shortening depends directly on the plasma formation time, which in turn is dependent on the applied laser intensity. It is envisaged that this plasma shutter will be used as a tool for pulse shaping in the search for laser pulse conditions to optimize conversion efficiency from laser energy to useable extreme ultraviolet (EUV) radiation for EUV source development.

Donnelly, T.; Mazoyer, M.; Lynch, A.; O'Sullivan, G.; O'Reilly, F.; Dunne, P.; Cummins, T. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)

2012-03-15T23:59:59.000Z

383

Quality of Life After Hypofractionated Concomitant Intensity-Modulated Radiotherapy Boost for High-Risk Prostate Cancer  

SciTech Connect

Purpose: To evaluate the change in health-related quality of life (QOL) of patients with high-risk prostate cancer treated using hypofractionated radiotherapy combined with long-term androgen deprivation therapy. Methods and Materials: A prospective Phase I-II study enrolled patients with any of the following: clinical Stage T3 disease, prostate-specific antigen level {>=}20 ng/mL, or Gleason score 8-10. Radiotherapy consisted of 45 Gy (1.8 Gy per fraction) to the pelvic lymph nodes with a concomitant 22.5 Gy intensity-modulated radiotherapy boost to the prostate, for a total of 67.5 Gy (2.7 Gy per fraction) in 25 fractions over 5 weeks. Daily image guidance was performed using three gold seed fiducials. Quality of life was measured using the Expanded Prostate Cancer Index Composite (EPIC), a validated tool that assesses four primary domains (urinary, bowel, sexual, and hormonal). Results: From 2004 to 2007, 97 patients were treated. Median follow-up was 39 months. Compared with baseline, at 24 months there was no statistically significant change in the mean urinary domain score (p = 0.99), whereas there were decreases in the bowel (p < 0.01), sexual (p < 0.01), and hormonal (p < 0.01) domains. The proportion of patients reporting a clinically significant difference in EPIC urinary, bowel, sexual, and hormonal scores at 24 months was 27%, 31%, 55%, and 60%, respectively. However, moderate and severe distress related to these symptoms was minimal, with increases of only 3% and 5% in the urinary and bowel domains, respectively. Conclusions: Hypofractionated radiotherapy combined with long-term androgen deprivation therapy was well tolerated. Although there were modest rates of clinically significant patient-reported urinary and bowel toxicity, most of this caused only mild distress, and moderate and severe effects on QOL were limited. Additional follow-up is ongoing to characterize long-term QOL.

Quon, Harvey [Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Cheung, Patrick C.F., E-mail: patrick.cheung@sunnybrook.ca [Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Loblaw, D. Andrew; Morton, Gerard; Pang, Geordi; Szumacher, Ewa; Danjoux, Cyril [Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON (Canada); Department of Radiation Oncology, University of Toronto, Toronto, ON (Canada); Choo, Richard [Department of Radiation Oncology, Mayo Clinic, Rochester, MN (United States); Kiss, Alex; Mamedov, Alexandre; Deabreu, Andrea [Odette Cancer Centre, Sunnybrook Health Sciences Centre, Toronto, ON (Canada)

2012-06-01T23:59:59.000Z

384

A Langmuir Probe Diagnostic for Use in Inhomogeneous, Time-Varying Plasmas Produced by High-Energy Laser Ablation  

SciTech Connect

Langmuir probes (LP) are used extensively to characterize plasma environments produced by radio frequency, pulsed plasma thrusters, and laser ablation. We discuss here the development of a LP diagnostic to examine high-density, high-temperature inhomogeneous plasmas such as those that can be created at the University of Rochester's Laboratory for Laser Energetics OMEGA facility. We have configured our diagnostic to examine the velocity of the plasma expanding from the target. We observe velocities of approximately 16-17 cm/{micro}s, with individual LP currents displaying complex structures, perhaps due to the multiple atomic species and ionization states that exist.

Patterson, J R; Emig, J A; Fournier, K B; Jenkins, P P; Trautz, K M; Seiler, S W; Davis, J F

2012-05-01T23:59:59.000Z

385

Laser device  

DOE Patents (OSTI)

A laser device includes a target position, an optical component separated a distance J from the target position, and a laser energy source separated a distance H from the optical component, distance H being greater than distance J. A laser source manipulation mechanism exhibits a mechanical resolution of positioning the laser source. The mechanical resolution is less than a spatial resolution of laser energy at the target position as directed through the optical component. A vertical and a lateral index that intersect at an origin can be defined for the optical component. The manipulation mechanism can auto align laser aim through the origin during laser source motion. The laser source manipulation mechanism can include a mechanical index. The mechanical index can include a pivot point for laser source lateral motion and a reference point for laser source vertical motion. The target position can be located within an adverse environment including at least one of a high magnetic field, a vacuum system, a high pressure system, and a hazardous zone. The laser source and an electro-mechanical part of the manipulation mechanism can be located outside the adverse environment. The manipulation mechanism can include a Peaucellier linkage.

Scott, Jill R. (Idaho Falls, ID); Tremblay, Paul L. (Idaho Falls, ID)

2007-07-10T23:59:59.000Z

386

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

387

Near-IR absorption in high-purity photothermorefractive glass and holographic optical elements: measurement and application for high-energy lasers  

SciTech Connect

Volume Bragg gratings (VBGs) in photothermorefractive (PTR) glass are widely used for laser beam control including high-power laser systems. Among them, spectral beam combining based on VBGs is one of the most promising. Achieving 100+ kW of combined laser beams requires the development of PTR glass and VBGs with an extremely low absorption coefficient and therefore methods of its measurement. This paper describes the calorimetric method that was developed for measuring a low absorption coefficient in PTR glass and VBGs. It is based on transmission monitoring of the intrinsic Fabry-Perot interferometer produced by the plane-parallel surfaces of the measured optical elements when heated by high-power laser radiation. An absorption coefficient at 1085 nm as low as 5x10{sup -5} cm{sup -1} is demonstrated in pristine PTR glass while an absorption coefficient as low as 1x10{sup -4} cm{sup -1} is measured in high-efficiency reflecting Bragg gratings with highest purity. The actual level of absorption in PTR glass allows laser beam control at the 10 kW level, while the 100 kW level would require active cooling and/or decreasing the absorption in PTR Bragg gratings to a value similar to that in virgin PTR glass.

Lumeau, Julien; Glebova, Larissa; Glebov, Leonid B.

2011-10-20T23:59:59.000Z

388

Particle Generation by Laser Ablation in Support of Chemical Analysis of High Level Mixed Waste from Plutonium Production Operations  

Science Conference Proceedings (OSTI)

Investigate particles produced by laser irradiation and their analysis by Laser Ablation Inductively Coupled Plasma Mass Spectroscopy (LA/ICP-MS), with a view towards optimizing particle production for analysis of high level waste materials and waste glass. LA/ICP-MS has considerable potential to increase the safety and speed of analysis required for the remediation of high level wastes from cold war plutonium production operations. In some sample types, notably the sodium nitrate-based wastes at Hanford and elsewhere, chemical analysis using typical laser conditions depends strongly on the details of sample history composition in a complex fashion, rendering the results of analysis uncertain. Conversely, waste glass materials appear to be better behaved and require different strategies to optimize analysis.

J. Thomas Dickinson; Michael L. Alexander

2001-11-30T23:59:59.000Z

389

Laser Glazing of Railroad Rails [Laser Applications Laboratory] - Nuclear  

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

Laser Glazing of Railroad Laser Glazing of Railroad Rails Capabilities Engineering Experimentation Reactor Safety Experimentation Aerosol Experiments System Components Laser Applications Overview Laser Oil & Gas Well Drilling Laser Heat Treatment Laser Welding of Metals On-line Monitoring Laser Beam Delivery Laser Glazing of Railroad Rails High Power Laser Beam Delivery Decontamination and Decommissioning Refractory Alloy Welding Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Laser Applications Laboratory Laser Glazing of Railroad Rails Project description: Laser glazing of rails. Category: Project with industrial partner (American Association of Railroads) Bookmark and Share

390

FREE-ELECTRON LASERS  

SciTech Connect

We can now produce intense, coherent light at wavelengths where no conventional lasers exist. The recent successes of devices known as free-electron lasers mark a striking confluence of two conceptual developments that themselves are only a few decades old. The first of these, the laser, is a product of the fifties and sixties whose essential characteristics have made it a staple resource in almost every field of science and technology. In a practical sense, what defines a laser is its emission of monochromatic, coherent light (that is, light of a single wavelength, with its waves locked in step) at a wavelength in the infrared, visible, or ultraviolet region of the electromagnetic spectrum. A second kind of light, called synchrotron radiation, is a by-product of the age of particle accelerators and was first observed in the laboratory in 1947. As the energies of accelerators grew in the 1960s and 70s, intense, incoherent beams of ultraviolet radiation and x--rays became available at machines built for high-energy physics research. Today, several facilities operate solely as sources of synchrotron light. Unlike the well-collimated monochromatic light emitted by lasers, however, this incoherent radiation is like a sweeping searchlight--more accurately, like the headlight of a train on a circular track--whose wavelengths encompass a wide spectral band. Now, in several laboratories around the world, researchers have exploited the physics of these two light sources and have combined the virtues of both in a single contrivance, the free-electron laser, or FEL (1). The emitted light is laserlike in its narrow, sharply peaked spectral distribution and in its phase coherence, yet it can be of a wavelength unavailable with ordinary lasers. Furthermore, like synchrotron radiation, but unlike the output of most conventional lasers, the radiation emitted by free-electron lasers can be tuned, that is, its wavelength can be easily varied across a wide range. The promise of this new technology extends from the fields of solid-state physics, gas- and liquid-phase photochemistry, and surface catalysis to futuristic schemes for ultrahigh-energy linear accelerators.

Sessler, A.M.; Vaughan, D.

1986-04-01T23:59:59.000Z

391

Generalized Courant-Snyder Theory and Kapchinskij-Vladimirskij Distribution For High-intensity Beams In A Coupled Transverse Focusing Lattice  

SciTech Connect

The Courant-Snyder (CS) theory and the Kapchinskij-Vladimirskij (KV) distribution for high-intensity beams in a uncoupled focusing lattice are generalized to the case of coupled transverse dynamics. The envelope function is generalized to an envelope matrix, and the envelope equation becomes a matrix envelope equation with matrix operations that are non-commutative. In an uncoupled lattice, the KV distribution function, first analyzed in 1959, is the only known exact solution of the nonlinear Vlasov-Maxwell equations for high-intensity beams including self-fields in a self-consistent manner. The KV solution is generalized to high-intensity beams in a coupled transverse lattice using the generalized CS invariant. This solution projects to a rotating, pulsating elliptical beam in transverse configuration space. The fully self-consistent solution reduces the nonlinear Vlasov-Maxwell equations to a nonlinear matrix ordinary differential equation for the envelope matrix, which determines the geometry of the pulsating and rotating beam ellipse. These results provide us with a new theoretical tool to investigate the dynamics of high-intensity beams in a coupled transverse lattice. A strongly coupled lattice, a so-called N-rolling lattice, is studied as an example. It is found that strong coupling does not deteriorate the beam quality. Instead, the coupling induces beam rotation, and reduces beam pulsation.

Hong QIn, Ronald Davidson

2011-07-18T23:59:59.000Z

392

Characterization of the backscattered radiation from petawatt laser matter interactions  

Science Conference Proceedings (OSTI)

The development of high peak power and energy laser systems require the assurance that any backscattered radiation will not lead to damage of the laser system. We present the characterization of the backscattered radiation for different target types and conditions at petawatt power levels and intensities (>10{sup 20}W/cm{sup 2}). We observe that radiation is generated between 700 and 900 nm, as well as the expected self emission and laser fundamental. The percentage of the incident light backscattered reduces as a function of the incident energy and is typically petawatt laser interactions.

Vernon, Edwina D.; Musgrave, Ian O.; Green, James; Heathcote, Robert; Lancaster, Kate L.; Mendes, Cedric; Hawkes, Steve J.; Hernandez-Gomez, Cristina; Pepler, Dave A

2008-06-20T23:59:59.000Z

393

The Impact of Intrinsic Heavy Quark Distributions in the Proton on New Physics Searches at the High Intensity Frontier  

SciTech Connect

The possibility of an intense proton facility, at 'Project X' or elsewhere, will provide many new opportunities for searches for physics beyond the Standard Model. A Project X can serve a yet broader role in the search for new physics, and in this note we highlight the manner in which thus-enabled studies of the flavor structure of the proton, particularly of its intrinsic heavy quark content, facilitate other direct and indirect searches for new physics. Intrinsic heavy quarks in both light and heavy hadrons play a key role in searches for physics BSM with hadrons - and their study at the Intensity Frontier may prove crucial to establishing its existence.

Brodsky, Stanley; /SLAC; Gardner, Susan; /Kentucky U.

2012-02-16T23:59:59.000Z

394

Fusion pumped laser  

SciTech Connect

Apparatus is provided for generating energy in the form of laser radiation. A tokamak fusion reactor is provided for generating a long, or continuous, pulse of high-energy neutrons. The tokamak design provides a temperature and a magnetic field which is effective to generate a neutron flux of at least 10.sup.15 neutrons/cm.sup.2.s. A conversion medium receives neutrons from the tokamak and converts the high-energy neutrons to an energy source with an intensity and an energy effective to excite a preselected lasing medium. The energy source typically comprises fission fragments, alpha particles, and radiation from a fission event. A lasing medium is provided which is responsive to the energy source to generate a population inversion which is effective to support laser oscillations for generating output radiation.

Pappas, Daniel S. (Los Alamos, NM)

1989-01-01T23:59:59.000Z

395

AGS intensity upgrades  

SciTech Connect

After the successful completion of the AGS Booster and several upgrades of the AGS, a new intensity record of 6.3 x 10{sup 13} protons per pulse accelerated to 24 GeV was achieved. The high intensity slow-extracted beam program at the AGS typically serves about five production targets and about eight experiments including three rare Kaon decay experiments. Further intensity upgrades are being discussed that could increase the average delivered beam intensity by up to a factor of four.

Roser, T.

1995-12-01T23:59:59.000Z

396

High efficiency cholesteric liquid crystal lasers with an external stable resonator  

E-Print Network (OSTI)

Shirvani-Mahdavi,1,2 Shima Fardad,2 Ezeddin Mohajerani,1 and Shin-Tson Wu2* 1 Laser and Plasma Research

Richardson, Martin C.

397

Circularly polarized high-efficiency cholesteric liquid crystal lasers with a tunable  

E-Print Network (OSTI)

retarder Hamidreza Shirvani-Mahdavi,1,2 Ezeddin Mohajerani,1 and Shin-Tson Wu2* 1 Laser and Plasma Research

Wu, Shin-Tson

398

Promising high-pressure DF - CO{sub 2} laser for amplifying picosecond radiation pulses  

Science Conference Proceedings (OSTI)

A scheme of the experiment is described and the results of measuring the small-signal gain in the active medium of a pulsed chemical DF - CO{sub 2} laser at a medium pressure in the range from 1 to 2.5 atm are reported. The values obtained (above 5 m{sup -1} at a pressure of 2.5 atm) make this laser a promising final amplifier of a multiterawatt laser system in the 10-{mu}m wavelength region. (lasers)

Agroskin, V Ya; Bravy, B G; Vasil'ev, G K; Kashtanov, S A; Makarov, E F; Sotnichenko, S A; Chernyshev, Yu A [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

2012-10-31T23:59:59.000Z

399

Advanced laser processing and photoluminescence characterisation of high efficiency silicon solar cells.  

E-Print Network (OSTI)

??Many current technologies used in solar cell fabrication have been successfully adapted from the integrated circuits industry. The success of laser processing applications in this… (more)

Abbott, Malcolm David

2006-01-01T23:59:59.000Z

400

Low-cost, highly efficient, and tunable ultrafast laser technology based on directly diode-pumped Cr:Colquiriites  

E-Print Network (OSTI)

This doctoral project aims to develop robust, ultra low-cost ($5,000-20,000), highly-efficient, and tunable femtosecond laser technology based on diode-pumped Cr:Colquiriite gain media (Cr:LiCAF, Cr3+:LiSAF and Cr:LiSGaF). ...

Demirbas, Umit

2010-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "high intensity laser" 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

Laser supported solid state absorption fronts in silica  

SciTech Connect

We develop a model based on simulation and experiment that explains the behavior of solid-state laser-supported absorption fronts generated in fused silica during high intensity (up to 5GW/cm{sup 2}) laser exposure. We find that the absorption front velocity is constant in time and is nearly linear in laser intensity. Further, this model can explain the dependence of laser damage site size on these parameters. This behavior is 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. The regime of parameter space critical to this problem spans and extends that measured by other means. It serves as a platform for understanding general laser-matter interactions in dielectrics under a variety of conditions.

Carr, C W; Bude, J D

2010-02-09T23:59:59.000Z

402

Laser-Material Interactions: A Study of Laser Energy Coupling with Solids  

E-Print Network (OSTI)

1971) Effects of High-Power Laser Radiation, Academic Presin Effects of High-Power Laser Radiation, (Academic Press,for modeling gas discharge lasers", Boulder, Colo. : Univ.

Shannon, M.A.

2009-01-01T23:59:59.000Z

403

Final LDRD report : science-based solutions to achieve high-performance deep-UV laser diodes.  

SciTech Connect

We present the results of a three year LDRD project that has focused on overcoming major materials roadblocks to achieving AlGaN-based deep-UV laser diodes. We describe our growth approach to achieving AlGaN templates with greater than ten times reduction of threading dislocations which resulted in greater than seven times enhancement of AlGaN quantum well photoluminescence and 15 times increase in electroluminescence from LED test structures. We describe the application of deep-level optical spectroscopy to AlGaN epilayers to quantify deep level energies and densities and further correlate defect properties with AlGaN luminescence efficiency. We further review our development of p-type short period superlattice structures as an approach to mitigate the high acceptor activation energies in AlGaN alloys. Finally, we describe our laser diode fabrication process, highlighting the development of highly vertical and smooth etched laser facets, as well as characterization of resulting laser heterostructures.

Armstrong, Andrew M.; Miller, Mary A.; Crawford, Mary Hagerott; Alessi, Leonard J.; Smith, Michael L.; Henry, Tanya A.; Westlake, Karl R.; Cross, Karen Charlene; Allerman, Andrew Alan; Lee, Stephen Roger

2011-12-01T23:59:59.000Z

404

Numerical simulation of transient, incongruent vaporization induced by high power laser  

Science Conference Proceedings (OSTI)

A mathematical model and numerical calculations were developed to solve the heat and mass transfer problems specifically for uranum oxide subject to laser irradiation. It can easily be modified for other heat sources or/and other materials. In the uranium-oxygen system, oxygen is the preferentially vaporizing component, and as a result of the finite mobility of oxygen in the solid, an oxygen deficiency is set up near the surface. Because of the bivariant behavior of uranium oxide, the heat transfer problem and the oxygen diffusion problem are coupled and a numerical method of simultaneously solving the two boundary value problems is studied. The temperature dependence of the thermal properties and oxygen diffusivity, as well as the highly ablative effect on the surface, leads to considerable non-linearities in both the governing differential equations and the boundary conditions. Based on the earlier work done in this laboratory by Olstad and Olander on Iron and on Zirconium hydride, the generality of the problem is expanded and the efficiency of the numerical scheme is improved. The finite difference method, along with some advanced numerical techniques, is found to be an efficient way to solve this problem.

Tsai, C.H.

1981-01-01T23:59:59.000Z

405

High-precision diode-laser-based temperature measurement for air refractive index compensation  

Science Conference Proceedings (OSTI)

We present a laser-based system to measure the refractive index of air over a long path length. In optical distance measurements, it is essential to know the refractive index of air with high accuracy. Commonly, the refractive index of air is calculated from the properties of the ambient air using either Ciddor or Edlen equations, where the dominant uncertainty component is in most cases the air temperature. The method developed in this work utilizes direct absorption spectroscopy of oxygen to measure the average temperature of air and of water vapor to measure relative humidity. The method allows measurement of temperature and humidity over the same beam path as in optical distance measurement, providing spatially well-matching data. Indoor and outdoor measurements demonstrate the effectiveness of the method. In particular, we demonstrate an effective compensation of the refractive index of air in an interferometric length measurement at a time-variant and spatially nonhomogeneous temperature over a long time period. Further, we were able to demonstrate 7 mK RMS noise over a 67 m path length using a 120 s sample time. To our knowledge, this is the best temperature precision reported for a spectroscopic temperature measurement.

Hieta, Tuomas; Merimaa, Mikko; Vainio, Markku; Seppae, Jeremias; Lassila, Antti

2011-11-01T23:59:59.000Z

406

Assessment of Electrical, Efficiency, and Photometric Performance of Advanced Lighting Technologies: Dimmable Advanced Lighting Tech nologies -- Electronic Fluorescent, High-Intensity Discharge, and Light-Emitting Diode  

Science Conference Proceedings (OSTI)

This EPRI Technical Report is a compilation of four technical updates that address the basic dimming performance of advanced lighting sources: EPRI report 1018476 for linear fluorescent ballasts, 1018477 for hot and cold cathode compact fluorescent lamps, 1018479 for electronic high-intensity discharge (HID) ballasts, and 1018480 for light-emitting diode (LED) lighting. Chapter 1 provides a discussion of basic lighting control, the importance of considering power quality in lighting control, lighting con...

2008-12-22T23:59:59.000Z

407

Schwinger Vacuum Pair Production in Chirped Laser Pulses  

E-Print Network (OSTI)

The recent developments of high intensity ultra-short laser pulses have raised the hopes of observing Schwinger vacuum pair production which is one of the important non-perturbative phenomena in Quantum electrodynamics (QED). The quantitative analysis of realistic high intensity laser pulses is vital for understanding the effect of the field parameters on the momentum spectrum of the produced particles. In this study, we analyze chirped laser pulses with a sub-cycle structure, and investigate the effects of the chirp parameter on the momentum spectrum of the produced particles. The combined effect of the chirp and carrier phase of the laser pulse is also analyzed. These effects are qualitatively explained by investigating the turning point structure of the potential within the framework of the complex WKB scattering approach to pair production.

Cesim K. Dumlu

2010-06-19T23:59:59.000Z

408

The Simultaneous Measurement of Rainfall Intensity, Drop-Size Distribution, and the Scattering of Visible Light  

Science Conference Proceedings (OSTI)

Field measurements were made of the attenuation of a low-power. He-Ne laser beam over a 272-m path. Concurrently, high-resolution (10 s) measurements of rainfall intensity were obtained at several points along the path and drop-size distributions ...

C. D. Stow; S. G. Bradley; K. Paulson; L. Couper

1991-10-01T23:59:59.000Z

409

Driving high-gain shock-ignited inertial confinement fusion targets by green laser light  

Science Conference Proceedings (OSTI)

Standard direct-drive inertial confinement fusion requires UV light irradiation in order to achieve ignition at total laser energy of the order of 1 MJ. The shock-ignition approach opens up the possibility of igniting fusion targets using green light by reducing the implosion velocity and laser-driven ablation pressure. An analytical model is derived, allowing to rescale UV-driven targets to green light. Gain in the range 100-200 is obtained for total laser energy in the range 1.5-3 MJ. With respect to the original UV design, the rescaled targets are less sensitive to irradiation asymmetries and hydrodynamic instabilities, while operating in the same laser-plasma interaction regime.

Atzeni, Stefano; Marocchino, Alberto; Schiavi, Angelo [Dipartimento SBAI, Universita di Roma 'La Sapienza' and CNISM, Via A. Scarpa 14-16, I-00161 Roma (Italy)

2012-09-15T23:59:59.000Z

410

Laser-Driven Magnetic-Flux Compression in High-Energy-Density Plasmas  

E-Print Network (OSTI)

The demonstration of magnetic field compression to many tens of megagauss in cylindrical implosions of inertial confinement fusion targets is reported for the first time. The OMEGA laser [T.?R. Boehly et al., Opt. Commun. ...

Gotchev, O. V.

411

High temperature, magnetic field assisted (sub)THz quantum cascade laser  

E-Print Network (OSTI)

We demonstrate magnetic field assisted, (sub)THz quantum cascade laser operating above 200 K. This is achieved through the application of strong magnetic fields which provide an additional lateral confinement in order to ...

Wade, Aaron

412

Integrated high-repetition-rate femtosecond lasers at 1.55 [mu]m  

E-Print Network (OSTI)

Performance of state-of-the-art, electronic analog-to-digital converters is currently limited by the 100-fs aperture jitter. However, optical sampling can overcome the jitter limit by using femtosecond lasers that have ...

Byun, Hyunil

2010-01-01T23:59:59.000Z

413

Lawrence Livermore Laser Fusion Program: a status report  

SciTech Connect

The Laser Fusion Program at the Lawrence Livermore Laboratory is presently emerging from a three-year period of intensive development of the tools required for significant DT implosion experiments of continuously increasing scale. These diverse tools include target design codes, sophisticated target fabrication techniques, radically new diagnostics instrumentation, high peak- power-high brightness laser technology, and fully integrated laser-target- diagnostic irradiation facilities. These tools have recently led to the successful production of neutrons from compressed DT-containing targets together with a wealth of correlating plasma physics data. The current status of major program activities at LLL will be reviewed and major future milestones will be projected. (auth)

Krupke, W.F.

1975-04-15T23:59:59.000Z

414

Laser Detection Of Material Thickness  

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

Detection Of Material Thickness Detection Of Material Thickness Laser Detection Of Material Thickness There is provided a method for measuring material thickness. Available for thumbnail of Feynman Center (505) 665-9090 Email Laser Detection Of Material Thickness There is provided a method for measuring material thickness comprising: (a) contacting a surface of a material to be measured with a high intensity short duration laser pulse at a light wavelength which heats the area of contact with the material, thereby creating an acoustical pulse within the material: (b) timing the intervals between deflections in the contacted surface caused by the reverberation of acoustical pulses between the contacted surface and the opposite surface of the material: and (c) determining the thickness of the material by calculating the proportion of

415

Integrated Laser-Target Interaction Experiments on the RAL Petawatt Laser  

Science Conference Proceedings (OSTI)

Since the construction of the first Petawatt laser on the Nova laser facility at Lawrence Livermore National Laboratory we are witnessing the emergence of similar Petawatt-class laser systems at laboratories all around the world. This new generation of lasers, able to deliver several hundred joules of energy in a sub-picosecond pulse, has enabled a host of new discoveries to be made and continues to provide a valuable tool to explore new regimes in relativistic laser-plasma physics--encompassing high energy X-rays and -rays, relativistic electrons, intense ion beams, and superstrong magnetic fields. The coupling in the near-future of multi-kiloJoule Petawatt-class lasers with large-scale fusion lasers.including the NIF and Omega EP (US), LIL (France), and FIREX (Japan)--will further expand opportunities in fast ignition, high energy X-ray radiography, and high energy density physics research. The 500 J Petawatt laser at the Rutherford Appleton Laboratory is currently the highest energy short-pulse laser in the world. In this paper we describe a recent experimental campaign carried out on the facility. The campaign, performed by a large collaborative team from eight different laboratories, was designed to study a variety of relativistic laser-interaction phenomena including laser absorption, fast electron transport, proton heating, and high-brightness x-ray generation. The wide scope of the experiment necessitated the deployment of a very large set of diagnostics--in total twenty-five separate instruments. In order to obtain the most comprehensive set of measurements all twenty-five diagnostics were fielded simultaneously on every shot.

Patel, P K; Key, M H; Mackinnon, A J; Berry, R; Borghesi, M; Chambers, D M; Chen, H; Clarke, R; Damian, C; Eagleton, R; Freeman, R; Glenzer, S; Gregori, G; Heathcote, R; Hey, D; Izumi, N; Kar, S; King, J; Nikroo, A; Niles, A; Park, H S; Pasley, J; Patel, N; Shepherd, R; Snavely, R A; Steinman, D; Stoeckl, C; Storm, M; Town, R; Van Maren, R; Theobald, W; Wilks, S C; Zhang, B

2006-10-11T23:59:59.000Z

416

Preparation of diamond-like carbon and boron nitirde films by high-intensity pulsed ion beam deposition  

SciTech Connect

Intense ion beams (300-keV C{sup +}, O{sup +}, and H{sup +}, 20--30 kA, 50 to 400-ns pulsewidth, up to 0.3-Hz repetition rate) were used to prepare diamond-like carbon (DLC) and boron nitride (BN) films. Deposition rates of up to 25{plus_minus}5 nm/pulse were obtained with instantaneous rates exceeding 1 mm/s. Most films were uniform, light brown, translucent, and nonporous with some micron-size particulates. Raman and parallel electron energy loss spectroscopy indicated the presence of DLC. The films possessed favorable electron field-emission characteristics desirable for cold-cathode displays. Transmission electron microscopy (TEM) and transmission electron diffraction (TED) revealed that the C films contained diamond crystals with 25 to 125-nm grain size. BN films were composed of hexagonal, cubic and wurtzite phases.

Rej, D.J.; Davis, H.A. [Los Alamos National Lab., NM (United States); Remnev, G.E. [Tomsk Polytechnic Univ., Tomsk (Russian Federation). Nuclear Physics Institute.] [and others

1995-05-01T23:59:59.000Z