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X-Band Photo injector Beam Dynamics

Description: SLAC is studying the feasibility of using an X-band RF photocathode gun to produce low emittance bunches for applications such as a mono-energetic MeV {gamma} ray source (in collaboration with LLNL) and a photoinjector for a compact FEL. Beam dynamics studies are being done for a configuration consisting of a 5.5-cell X-band gun followed by several 53-cell high-gradient X-band accelerator structures. A fully 3D program, ImpactT, is used to track particles taking into account space charge forces… more
Date: December 13, 2011
Creator: Zhou, Feng; Adolphsen, Chris; Ding, Yuantao; Li, Zenghai & Vlieks, Arnold
Item Type: Refine your search to only Article
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X-ray diagnostics of hohlraum plasma flow

Description: In this study we use spectroscopy and x-ray imaging to investigate the macroscopic plasma flow in mm-sized laser-produced hohlraum plasmas. By using multiple diagnostics to triangulate the emission on a single experiment, we can pinpoint the position of dopants placed inside the hohlraum. X-ray emission from the foil has been used in the past to measure electron temperature. Here we analyze the spatial movement of dopant plasmas for comparison to hydrodynamic calculations.
Date: May 13, 1996
Creator: Back, C. A.; Glenzer, S. H.; Landen, O. L.; MacGowan, B. J. & Shepard, T. D.
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X-ray Induced Pinhole Closure in Point Projection X-ray Radiography

Description: In pinhole-assisted point-projection x-ray radiography (or ''backlighting''), pinholes are placed between the sample of interest and an x-ray source (or ''backlighter'') to effectively limit the source size and hence improve the spatial resolution of the system. Pinholes are generally placed close to such x-ray backlighters to increase the field-of-view, leading to possible vaporization and pinhole closure due to x-ray driven ablation, thereby potentially limiting the usefulness of this method.… more
Date: January 13, 2006
Creator: Bullock, A. B.; Landen, O. L.; Blue, B. E.; Edwards, J. & Bradley, D. K.
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X-Ray Microcalorimeters With Germanium Resistance Thermometers

Description: We report on the current of our work on x-ray microcalorimeters for use as high resolution x-ray spectrometers. To maximize the x-ray collecting area and the signal to noise ratio, the total heat capacity of the device must be minimized. This is best achieved if the calorimeter is divided into two components, a thermal sensor and an x-ray absorber. The thermal sensor is a neutron transmutation doped (NTD) germanium resistor made as small as possible to minimize the heat capacity of the calorime… more
Date: August 13, 1990
Creator: Labov, S.; Silver, E.; Pfafman, T.; Wai, Y. (Lawrence Livermore National Lab., CA (USA)); Beeman, J.; Goulding, F. et al.
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open access

X-ray microscope assemblies. Final report and metrology report

Description: This is the Final Report and Metrology Report prepared under Lawrence Livermore Laboratory Subcontract 9936205, X-ray Microscope Assemblies. The purpose of this program was to design, fabricate, and perform detailed metrology on an axisymmetric grazing-incidence x-ray microscope (XRMS) to be used as a diagnostic instrument in the Lawrence Livermore Laser Fusion Program. The optical configuration chosen for this device consists of two internally polished surfaces of revolution: an hyperboloid fa… more
Date: April 13, 1981
Creator: Zehnpfennig, T. F.
Item Type: Refine your search to only Report
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X-ray Optics and Diagnostics for the First Experiments on the Linac Coherent Light Source

Description: The Linac Coherent Light Source (LCLS) is a 1.5 to 15 {angstrom}-wavelength free-electron laser (FEL), currently proposed for the Stanford Linear Accelerator Center (SLAC). The photon output consists of high brightness, transversely coherent pulses with duration < 300 fs, together with a broad spontaneous spectrum with total power comparable to the coherent output. The output fluence, and pulse duration, pose special challenges for optical component and diagnostic designs. We discuss some of… more
Date: June 13, 2001
Creator: Wootton, A.; Arthur, J.; Barbee, T.; Bionta, R.; London, R.; Park, H. S. et al.
Item Type: Refine your search to only Article
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XPS studies of actinide materials. [X-ray photoemission spectroscopy, review]

Description: Applications of x-ray photoemission spectroscopy (XPS) to the study of actinide materials are reviewed. Examples discussed here include the band structures of thorium and uranium metal, the multiplet structure associated with the 5f electron states in oxides of the transuranium elements, the test for temporal configurations in NpO/sub 2/, crystal field splitting of the U 6p/sub /sup 3///sub 2// level in a series of uranyl compounds, mixed oxidation states in Cf/sub 7/O/sub 12/, and a test for t… more
Date: September 13, 1976
Creator: Veal, B. W.; Lam, D. J.; Hoekstra, H. R.; Diamond, H. & Carnall, W. T.
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Yahoo! Compute Coop (YCC): A Next-Generation Passive Cooling Design for Data Centers

Description: The purpose of the Yahoo! Compute Coop (YCC) project is to research, design, build and implement a greenfield "efficient data factory" and to specifically demonstrate that the YCC concept is feasible for large facilities housing tens of thousands of heat-producing computing servers. The project scope for the Yahoo! Compute Coop technology includes: - Analyzing and implementing ways in which to drastically decrease energy consumption and waste output. - Analyzing the laws of thermodynamics and i… more
Date: September 13, 2011
Creator: Robison, A. D.; Page, Christina & Lytle, Bob
Item Type: Refine your search to only Report
open access

Year 2000 Computing Challenge: Important Progress Made, Yet Much Work Remains to Ensure Delivery of Critical Services

Description: Testimony issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO discussed the progress being made in addressing the year 2000 computing challenge, focusing on: (1) the federal government's progress and the challenges that remain in correcting its systems; (2) state and local government year 2000 issues; and (3) the readiness of key public infrastructure and economic sectors."
Date: August 13, 1999
Creator: United States. General Accounting Office.
Item Type: Refine your search to only Text
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Year 2000 Computing Crisis: Additional Work Remains to Ensure Delivery of Critical Services

Description: Testimony issued by the General Accounting Office with an abstract that begins "Pursuant to a congressional request, GAO discussed federal agencies' progress in addressing the year 2000 computing challenge and outlined actions needed to ensure a smooth conversion to the next century, focusing on the: (1) status of the federal government's remediation of its mission-critical systems; (2) remaining challenges facing the government in ensuring the continuity of business operations, namely end-to-e… more
Date: April 13, 1999
Creator: United States. General Accounting Office.
Item Type: Refine your search to only Text
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Yemen: Background and U.S. Relations

Description: This report provides an overview and analysis of U.S.-Yemeni relations amidst evolving political change in Yemeni leadership, ongoing U.S. counterterrorism operations against Al Qaeda in the Arabian Peninsula (AQAP) operatives at large in Yemen's hinterlands, and international efforts to bolster the country's stability despite an array of daunting socio-economic problems.
Date: January 13, 2010
Creator: Sharp, Jeremy M.
Item Type: Refine your search to only Report
open access

''Yields of Radionuclides Created by Photonuclear Reactions on Be, C, Na, C1, and Ge, Using Bremsstrahlung of 150-MeV Electrons''

Description: The bremsstrahlung created by 150-MeV electrons impinging on a tantalum radiator was used to study photonuclear reactions on samples containing Be, C, Na, Cl and Ge. For Ge fifteen radioisotopes, ranging in half life between 2.6 min and 271 days, and in mass between 65 and 75, were obtained in sufficient amount to determine their yields quantitatively using known decay gamma-rays. Special equipment is described which was developed to create the bremsstrahlung using a beam-sharing mode, while mi… more
Date: December 13, 2001
Creator: Dickens, J.K.
Item Type: Refine your search to only Report
open access

The Z accelerator as a source of > 100 kJ of x-rays above 4.8 keV

Description: Recent K-shell scaling experiments on the 20 MA Z accelerator at Sandia National Laboratories have shown that large diameter (40 and 55 mm) arrays can be imploded with 80 to 210 wires of titanium or stainless steel. These implosions have produced up to 150 kJ of > 4.5 keV x-rays and 65 kJ of > 6.0 keV x-rays in 7 to 18 ns FWHM pulses. This is a major advance in plasma radiation source (PRS) capability since there is presently limited test capability above 3 keV. In fact, Z produces more > 4.5 k… more
Date: April 13, 1998
Creator: Deeney, C.; Coverdale, C. A. & Spielman, R. B.
Item Type: Refine your search to only Article
open access

Z-Pinch Drivers for Shock Physics Research

Description: The recent development of Z pinch drivers for producing intense radiation envkomn~ enables study of physical and mechanical properties of condensed materials in regimes previously inaccessible in the Mm-am-y. With Z pinch radiation sources, it is possible fo subject mm-sized sampies to pianar compressions of a fe w Mbar. Tie-resolved velocity interferometry was used to perform the first shock loading and unloading profiles in Al and Be for ablatively driven shock$s to 3 Mbar and the first iseri… more
Date: October 13, 1998
Creator: Asay, J.; Bernard, M.; Clark, B.; Fleming, K.; Hall, C.; Holland, K. et al.
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The "Z" Pulsed Radiation Source: Recent Developments in Equation of State Measurement Capabilities

Description: The Sandia Z machine is a source of intense radiation which can be used to drive ablative shocks for equation of state studies. In developing the capability to diagnose these types of studies on Z, techniques commonly used in conventional impact generated experiments were leveraged. The primary diagnostic transferred was velocity interferome~, VLSAR, [1] which not only provides Hugoniot particle velocity measurements, but also indications of shock stability and wave attenuation. In addition to … more
Date: October 13, 1998
Creator: Asay, J.R.; Chandler, G.; Clark, B.; Fleming, K.; Hall, C.A.; Holland, K. et al.
Item Type: Refine your search to only Article
open access

ZEOLITE CHARACTERIZATION TESTING

Description: The Savannah River Site isolates tritium from its process streams for eventual recycling. This is done by catalyzing the formation of tritiated water (from process streams) and then sorbing that water on a 3A zeolite (molsieve) bed. The tritium is recovered by regenerating the saturated bed into a Mg-based water cracking unit. The process described has been in use for about 15 years. Recently chloride stress corrosion cracking (SCC) was noted in the system piping. This has resulted in the need … more
Date: September 13, 2007
Creator: Jacobs, W & Herbert Nigg, H
Item Type: Refine your search to only Article
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Zephyr: A secure Internet-based process to streamline engineering procurements using the World Wide Web

Description: Lawrence Livermore National Laboratory (LLNL) is piloting an Internet- based paperless process called `Zephyr` to streamline engineering procurements. Major benefits have accrued by using Zephyr in reducing procurement time, speeding the engineering development cycle, facilitating industrial collaboration, and reducing overall costs. Programs at LLNL are benefiting by the efficiencies introduced since implementing Zephyr`s engineering and commerce on the Internet.
Date: August 13, 1996
Creator: Jordan, C. W.; Cavitt, R. E.; Niven, W. A.; Warren, F. E.; Taylor, S. S.; Sharick, T. M. et al.
Item Type: Refine your search to only Article
open access

ZIRCEX KINETICS AND URANIUM LOSS STUDY

Description: A study was made of the effects of temperature, impurities in the hydrogen chloride, flow rates, and niobium content on both the reaction rates and insoluble uranium losses in the Zircex Process is presented. (W.L.H.)
Date: November 13, 1957
Creator: Carter, T. J., Jr. & Stone, R. A.
Item Type: Refine your search to only Report
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Zircex Kinetics And Uranium Loss Study

Description: "A study was made of the effects of temperature, impurities in the hydrogen chloride, flow rates, and niobium content on both the reaction rates and insoluble uranium losses in the Zircex Process is presented."
Date: November 13, 1957
Creator: Carter, Jr, T. J. & Stone, R. A.
Item Type: Refine your search to only Report
open access

Zonal flow excitation by drift waves in toroidal plasmas

Description: Recent 3D gyrokinetic and gyrofluid simulations in toroidal plasmas have demonstrated that zonal flows play a crucial role in regulating the nonlinear evolution of electrostatic drift-wave instabilities such as the ion temperature gradient (ITG) modes and, as a consequence, the level of the anomalous ion thermal transport, and that zonal flows could be spontaneously excited by ITG turbulence, suggesting parametric instability processes as the generation mechanism. Diamond et. al. have proposed … more
Date: June 13, 2000
Creator: Chen, L; Lin, Z. & White, R.
Item Type: Refine your search to only Article
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