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Modal photon densities

Description: The short wavelength laser code XRASER uses line raidation fields whose dimensions are photons/mode. In this document, we discuss modal photon densities and provide formulas relating these units to units more familiar to the LLNL community.
Date: June 21, 1982
Creator: Hagelstein, P.L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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2660 A holographic interferometry of laser produced plasmas from tilted disk targets

Description: Using double exposure holographic interferometry, an investigation has been made of the Nd laser produced plasmas surrounding disk targets irradiated at different angles of incidence. Measurements have produced a detailed description of the plasma profile necessary for realistic simulations of resonance absorption. A 2660A 15 psec probe pulse is produced by frequency quadrupling a fraction of the main Nd laser pulse from the Janus laser. F/1 and f/10 lenses were utilized to irradiate the target… more
Date: October 21, 1977
Creator: Auerbach, J.M.; Attwood, D.T.; Lee, P.H.Y. & Sweeney, D.W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A table-top femtosecond time-resolved soft x-ray transient absorption spectrometer

Description: A laser-based, table-top instrument is constructed to perform femtosecond soft x-ray transient absorption spectroscopy. Ultrashort soft x-ray pulses produced via high-order harmonic generation of the amplified output of a femtosecond Ti:sapphire laser system are used to probe atomic core-level transient absorptions in atoms and molecules. The results provide chemically specific, time-resolved dynamics with sub-50-fs time resolution. In this setup, high-order harmonics generated in a Ne-filled c… more
Date: May 21, 2008
Creator: Leone, Stephen; Loh, Zhi-Heng; Khalil, Munira; Correa, Raoul E. & Leone, Stephen R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Use of molecular modeling to determine the interaction and competition of gases within coal for carbon dioxide sequestration, Annual Technical Progress Report: 2005

Description: Molecular modeling was employed to both visualize and probe our understanding of carbon dioxide sequestration within a bituminous coal. A large-scale (>20,000 atoms) 3D molecular representation of Pocahontas No. 3 coal was generated. This model was constructed based on a the review data of Stock and Muntean, oxidation and decarboxylation data for aromatic clustersize frequency of Stock and Obeng, and the combination of Laser Desorption Mass Spectrometry data with HRTEM, enabled the inclusion… more
Date: April 21, 2006
Creator: Evanseck, Jeffrey D.; Madura, Jeffry D. & Mathews, Jonathan P.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Portable, Low-cost NMR with Laser-Lathe Lithography Produced

Description: Nuclear Magnetic Resonance (NMR) is unsurpassed in its ability to non-destructively probe chemical identity. Portable, low-cost NMR sensors would enable on-site identification of potentially hazardous substances, as well as the study of samples in a variety of industrial applications. Recent developments in RF microcoil construction (i.e. coils much smaller than the standard 5 mm NMR RF coils), have dramatically increased NMR sensitivity and decreased the limits-of-detection (LOD). We are using… more
Date: December 21, 2006
Creator: Herberg, J. L.; Demas, V.; Malba, V.; Bernhardt, A.; Evans, L.; Harvey, C. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Direct Determination of the Ionization Energies of PtC, PtO, and PtO2 with VUVRadiation

Description: Photoionization efficiency curves were measured for gas-phase PtC, PtO, and PtO2 using tunable vacuum ultraviolet (VUV) radiation at the Advanced Light Source. The molecules were prepared by laser ablation of a platinum tube, followed by reaction with CH4 or N2O and supersonic expansion. These measurements providethe first directly measured ionization energy for PtC, IE(PtC) = 9.45 +- 0.05 eV. The direct measurement also gives greatly improved ionization energies for the platinum oxides, IE(PtO… more
Date: July 21, 2008
Creator: Citir, Murat; Metz, Ricardo B.; Belau, Leonid & Ahmed, Musahid
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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In-situ Studies of the Martensitic Transformation in Ti Thin Films using the Dynamic Transmission Microscope (DTEM)

Description: The {alpha} to {beta} transition in pure Ti occurs mainly by a 'martensitic type' phase transformation. In such transformations, growth rates and interface velocities tend to be very large, on the order of 10{sup 3} m/s, making it difficult to observe the transformation experimentally. With thin films, it becomes even more difficult to observe, since the large surface augments the nucleation and transformation rates to levels that require nanosecond temporal resolution for experimental observat… more
Date: November 21, 2005
Creator: LaGrange, T. B.; Campbell, G. H.; Colvin, J. D.; King, W. E.; Browning, N. D.; Armstrong, M. R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Shot Automation for the National Ignition Facility

Description: A shot automation framework has been developed and deployed during the past year to automate shots performed on the National Ignition Facility (NIF) using the Integrated Computer Control System This framework automates a 4-8 hour shot sequence, that includes inputting shot goals from a physics model, set up of the laser and diagnostics, automatic alignment of laser beams and verification of status. This sequence consists of set of preparatory verification shots, leading to amplified system shot… more
Date: September 21, 2005
Creator: Lagin, L. J.; Bettenhausen, R. C.; Beeler, R. G.; Bowers, G. A.; Carey, R.; Casavant, D. D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Structural transformations in Sc/Si multilayers irradiated by EUVlasers

Description: Multilayer mirrors for the extreme ultraviolet (EUV) are keyelements for numerous applications of coherent EUV sources such as newtabletop lasers and free-electron lasers. However the field ofapplications is limited by the radiation and thermal stability of themultilayers. Taking into account the growing power of EUV sources thestability of the optics becomes crucial. To overcome this problem it isnecessary to study the degradation of multilayers and try to increasetheir temporal and thermal st… more
Date: August 21, 2007
Creator: Voronov, D. L.; Zubarev, E. N.; Pershyn, Y. P.; Sevryukova, V. A.; Kondratenko, V. V.; Vinogradov, A. V. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Synchrotron Facilities and Free Electron Lasers

Description: Synchrotron radiation (SR) is electromagnetic radiation emitted when a charged particle travels along a curved trajectory. Initially encountered as a nuisance around orbits of high energy synchrotron accelerators, it gradually became an indispensable research tool in many applications: crystallography, X-ray lithography, micromechanics, structural biology, microprobe X-ray experiments, etc. So-called first generation SR sources were exploiting SR in parasitic mode at electron accelerators built… more
Date: December 21, 2007
Creator: Vaclav, Vylet; U., /Duke & Liu, James
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Studies of Closure Phenomena in Pinholes Irradiated by Nd Laser Pulses

Description: The plasma closure of spatial filter pinholes is a critical parameter in the performance of high energy glass laser systems. Using 50 to 100 J, 300 psec FWHM laser pulses on the Janus laser, an investigation has been made on closure effects in 300 ..mu..m to 500 ..mu..m diameter pinholes of various materials and thicknesses. Calorimetry measurements have yielded data on pinhole transmission and intensity loading on the periphery of the pinhole. Ultrafast streak photography measurements indicate… more
Date: August 21, 1978
Creator: Auerbach, J. M.; Holmes, N. C.; Hunt, J. T. & Linford, G. J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Pulsed-laser heating: a tool for studying degradation of materials subjected to repeated high-temperature excursions

Description: The use of pulsed-laser heating was evaluated as a means to obtain high cyclic peak temperatures with short rise times. A two-stage neodymium glass laser was used which produces a 600-..mu..s pulse with energy outputs of up to 100 J. Small disk-shaped samples of AISI 4340 steel served as targets. Some of these were coated with a tungsten deposit. The rear face of some of the targets was instrumented for evaluation of temperature, strain, and stress response. Post-shot metallographic evaluations… more
Date: August 21, 1980
Creator: Goldberg, A. & Cornell, R.H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Sol-gel coatings for high power laser optics-past, present and future

Description: An investigation into the preparation of sol-gel coatings for high power lasers was started at LLNL in 1983 and AR coatings were successfully developed for use in the Nova laser in 1984. Several other large lasers now use these coatings. Subsequent work on HR coatings resulted in AlOOH/SiO{sub 2} and later ZrO{sub 2} or HfO{sub 2}/SiO{sub 2} systems of good optical performance. The use of organic polymer binders gave increased damage threshold and enhanced optical performance. We are in the pro… more
Date: December 21, 1993
Creator: Thomas, I. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Ionization balance and gain calculations for neon-like selenium x-ray laser plasmas

Description: The authors have developed compact collisional-radiative models to describe the ionization balance and excitation mechanisms in neon-like selenium x-ray laser plasmas. These models can be used for calculations of the ionization dynamics, detailed emission spectra, and gain coefficients. Careful attention has been paid to indirect processes such as dielectronic recombination, excitation-autoionization, and resonant excitation. They discuss the importance of different atomic processes and model a… more
Date: January 21, 1994
Creator: Osterheld, A. L.; Walling, R. S. & Young, B. K. F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Blue and Green Light? Wavelength Scaling for NIF

Description: Use of the National Ignition Facility to also output frequency-doubled (.53{micro}m) laser light would allow significantly more energy to be delivered to targets as well as significantly greater bandwidth for beam smoothing. This green light option could provide access to new ICF target designs and a wider range of plasma conditions for other applications. The wavelength scaling of the interaction physics is a key issue in assessing this green light option. Wavelength scaling theory based on th… more
Date: August 21, 2003
Creator: Suter, L.; Miller, M.; Moody, J. & Kruer, W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Laser- and Radar-based Mission Concepts for Suborbital and Spaceborne Monitoring of Seismic Surface Waves

Description: The development of a suborbital or spaceborne system to monitor seismic waves poses an intriguing prospect for advancing the state of seismology. This capability would enable an unprecedented global mapping of the velocity structure of the earth's crust, understanding of earthquake rupture dynamics and wave propagation effects, and event source location, characterization and discrimination that are critical for both fundamental earthquake research and nuclear non-proliferation applications. As … more
Date: September 21, 2004
Creator: Foxall, W; Schultz, C A & Tralli, D M
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Laser System for Photoelectron and X-Ray Production in the PLEIADES Compton Light Source

Description: The PLEIADES (Picosecond Laser-Electron Interaction for the Dynamic Evaluation of Structures) facility provides tunable short x-ray pulses with energies of 30-140 keV and pulse durations of 0.3-5 ps by scattering an intense, ultrashort laser pulse off a 35-75 MeV electron beam. Synchronization of the laser and electron beam is obtained by using a photoinjector gun, and using the same laser system to generate the electrons and the scattering laser. The Ti Ti:Sapphire, chirped pulse amplification… more
Date: April 21, 2005
Creator: Gibson, D J; Barty, C J; Betts, S M; Crane, J K & Jovanovic, I
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Precision Micron Hole Drilling using a Frequency Doubled, Diode Pumped Solid State Laser

Description: This work represents the second phase of a program to demonstrate precision laser drilling with minimal Heat Affected Zone. The technique uses a Diode Pumped Solid State Laser with two wavelengths and two modes of operation. The fundamental mode of the DPSSL at 1.06 microns is used to drill a hole with a diameter of a fraction of a millimeter diameter in a millimeter thick substrate quickly, but with low precision. This hole is then machined to precision dimensions using the second harmonic of … more
Date: April 21, 2004
Creator: Friedman, H W & Pierce, E L
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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An Assessment of Molecular Dynamic Force Fields for Silica for Use in Simulating Laser Damage Mitigation

Description: We compare force fields (FF's) that have been used in molecular dynamic (MD) simulations of silica in order to assess their applicability for use in simulating IR-laser damage mitigation. Although pairwise FF?s obtained by fitting quantum mechanical calculations such as the BKS and CHIK potentials have been shown to reproduce many of the properties of silica including the stability of silica polymorphs and the densification of the liquid, we show that melting temperatures and fictive temperatur… more
Date: October 21, 2010
Creator: Soules, T F; Gilmer, G H; Matthews, M J; Stolken, J S & Feit, M D
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The Mercury Laser Advances Laser Technology for Power Generation

Description: The National Ignition Facility (NIF) at Lawrence Livermore Laboratory is on target to demonstrate 'breakeven' - creating as much fusion-energy output as laser-energy input. NIF will compress a tiny sphere of hydrogen isotopes with 1.8 MJ of laser light in a 20-ns pulse, packing the isotopes so tightly that they fuse together, producing helium nuclei and releasing energy in the form of energetic particles. The achievement of breakeven will culminate an enormous effort by thousands of scientists … more
Date: January 21, 2009
Creator: Ebbers, C A; Caird, J & Moses, E
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Solid Collection Efforts: Ta Collimator Evaluation

Description: Ta collimator sets that were part of the gated x-ray detector diagnostic (GXD) at NIF were analyzed for debris distribution and damage in 2011. These disks (ranging in thickness from 250 to 750 {mu}m) were fielded approximately 10 cm from target chamber center (TCC) on various symcap, THD and re-emit shots. The nose cone holder and forward Ta collimator (facing target chamber center, TCC) from all shots show evidence of surface melt. Non-destructive analysis techniques such as optical microscop… more
Date: November 21, 2011
Creator: Gostic, J M
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Unification and extension of the similarity scaling criteria and mixing transition for studying astrophysics using high energy density laboratory experiments or numerial simulations

Description: The Euler similarity criteria for laboratory experiments and time-dependent mixing transition are important concepts introduced recently for application to prediction and analysis of astrophysical phenomena. However Euler scaling by itself provides no information on the distinctive spectral range of high Reynolds number turbulent flows found in astrophysics situations. On the other hand, time-dependent mixing transition gives no indication on whether a flow that just passed the mixing transitio… more
Date: August 21, 2006
Creator: Zhou, Y
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Picosecond x-ray spectral studies

Description: Temporally and spectrally resolved x-ray emission is an important diagnostic tool for the study of target heating and compression induced by sub-nanosecond laser pulses. The use of the Livermore 15 psec x-ray streak camera to record x-ray emissions in the 1-10 keV range is described. In particular, significant progress is reported during the past year in defining the camera as a quantitative diagnostic instrument, and its implementation for multi-channel, time resolved K-edge filter measurement… more
Date: July 21, 1976
Creator: Attwood, D. T. & Coleman, L. W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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