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open access

Investigation of Sodium Distribution in Phosphate Glasses Using Spin-Echo {sup 23}Na NMR

Description: The spatial arrangement of sodium cations for a series of sodium phosphate glasses, xNa{sub 2}O(100-x)P{sub 2}O{sub 5} (x<55), were investigated using {sup 23}Na spin-echo NMR spectroscopy. The spin-echo decay rate is a function of the Na-Na homonuclear dipolar coupling and is related to the spatial proximity of neighboring Na nuclei. The spin-echo decay rate in these sodium phosphate glasses increases non-linearly with higher sodium number density, and thus provides a measure of the Na-Na e… more
Date: September 16, 1999
Creator: ALAM, TODD M.; BOYLE, TIMOTHY J.; BROW, RICHARD K.; CLICK, CAROL C.; CONZONE, SAM; McLAUGHLIN, JAY et al.
open access

HIGH-INTENSITY, HIGH CHARGE-STATE HEAVY ION SOURCES

Description: There are many accelerator applications for high intensity heavy ion sources, with recent needs including dc beams for RIA, and pulsed beams for injection into synchrotrons such as RHIC and LHC. The present status of sources producing high currents of high charge state heavy ions is reviewed. These sources include ECR, EBIS, and Laser ion sources. Benefits and limitations for these type sources are described. Possible future improvements in these sources are also mentioned.
Date: August 16, 2004
Creator: ALESSI,J. G.
open access

FUTURE PLANS AT BNL: RHIC-II AND eRHIC.

Description: The development of future facilities relevant to the study of deep inelastic scattering at BNL is described.
Date: April 16, 2007
Creator: ARONSON,S.
open access

Data Torturing and the Misuse of Statistical Tools

Description: Statistical concepts, methods, and tools are often used in the implementation of statistical thinking. Unfortunately, statistical tools are all too often misused by not applying them in the context of statistical thinking that focuses on processes, variation, and data. The consequences of this misuse may be ''data torturing'' or going beyond reasonable interpretation of the facts due to a misunderstanding of the processes creating the data or the misinterpretation of variability in the data. In… more
Date: August 16, 1999
Creator: Abate, Marcey L.
open access

Growth and Fabrication of GaN/AlGaN Heterojunction Bipolar Transistor

Description: A GaN/AlGaN heterojunction bipolar transistor structure with Mg doping in the base and Si Doping in the emitter and collector regions was grown by Metal Organic Chemical Vapor Deposition in c-axis Al(2)O(3). Secondary Ion Mass Spectrometry measurements showed no increase in the O concentration (2-3x10(18) cm(-3)) in the AlGaN emitter and fairly low levels of C (~4-5x10(17) cm (-3)) throughout the structure. Due to the non-ohmic behavior of the base contact at room temperature, the current gain … more
Date: March 16, 1999
Creator: Abernathy, C. R.; Baca, A. G.; Cao, X. A.; Cho, H.; Dang, G. T.; Donovan, S. M. et al.
open access

Corrosion of structural materials by lead-based reactor coolants.

Description: Advanced nuclear reactor design has, in recent years, focused increasingly on the use of heavy-liquid-metal coolants, such as lead and lead-bismuth eutectic. Similarly, programs on accelerator-based transmutation systems have also considered the use of such coolants. Russian experience with heavy-metal coolants for nuclear reactors has lent credence to the validity of this approach. Of significant concern is the compatibility of structural materials with these coolants. We have used a thermal c… more
Date: November 16, 2000
Creator: Abraham, D. P.; Leibowitz, L.; Maroni, V. A.; McDeavitt, S. M. & Raraz, A. G.
open access

Multidimensional solitons in fiber arrays

Description: We demonstrate that nonlinear optical fiber arrays can support stable soliton-like pulses with finite energy. The bound state that we have found is localized both in time and in a spatial domain in the direction perpendicular to the pulse propagation. We have proved the boundedness of the Hamiltonian function for the array. Finally, numerical studies support our analytical conclusions.
Date: August 16, 1993
Creator: Aceves, A. B.; De Angelis, C.; Rubenchik, A. M. & Turitsyn, S. K.
open access

Computer modeling in the design and evaluation of electric and hybrid vehicles

Description: This demonstration project uses modern simulation techniques to illustrate the important technologies and design variables that an auto-designer would consider in production a high efficiency, low emissions vehicle. Simulation and modeling techniques use the idea of capturing the relationships between real components of the systems with mathematical equations. These equations are then solved on a computer to simulate the behavior or performance of the system under various conditions. In the cur… more
Date: August 16, 1996
Creator: Aceves, S. M.; Smith, J. R. & Johnson, N. L.
open access

Waste form development and characterization in pyrometallurgical treatment of spent nuclear fuel.

Description: Electrometallurgical treatment is a compact, inexpensive method that is being developed at Argonne National Laboratory to deal with spent nuclear fuel, primarily metallic and oxide fuels. In this method, metallic nuclear fuel constituents are electrorefined in a molten salt to separate uranium from the rest of the spent fuel. Oxide and other fuels are subjected to appropriate head end steps to convert them to metallic form prior to electrorefining. The treatment process generates two kinds of h… more
Date: April 16, 1998
Creator: Ackerman, J.
open access

Search for Dark Matter Satellites Using the FERMI-LAT

Description: Numerical simulations based on the {Lambda}CDM model of cosmology predict a large number of as yet unobserved Galactic dark matter satellites. We report the results of a Large Area Telescope (LAT) search for these satellites via the {gamma}-ray emission expected from the annihilation of weakly interacting massive particle (WIMP) dark matter. Some dark matter satellites are expected to have hard {gamma}-ray spectra, finite angular extents, and a lack of counterparts at other wavelengths. We soug… more
Date: August 16, 2012
Creator: Ackermann, M.; Albert, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D. et al.
open access

Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at sqrt(sNN) = 200 GeV

Description: Identified mid-rapidity particle spectra of {pi}{sup {+-}}, K{sup {+-}}, and p({bar p}) from 200 GeV p+p and d+Au collisions are reported. A time-of-flight detector based on multi-gap resistive plate chamber technology is used for particle identification. The particle-species dependence of the Cronin effect is observed to be significantly smaller than that at lower energies. The ratio of the nuclear modification factor (R{sub dAu}) between (p+ {bar p}) and charged hadrons (h) in the transverse … more
Date: September 16, 2003
Creator: Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
open access

Securing collaborative environments

Description: The diverse set of organizations and software components involved in a typical collaboratory make providing a seamless security solution difficult. In addition, the users need support for a broad range of frequency and locations for access to the collaboratory. A collaboratory security solution needs to be robust enough to ensure that valid participants are not denied access because of its failure. There are many tools that can be applied to the task of securing collaborative environments and t… more
Date: May 16, 2002
Creator: Agarwal, Deborah; Jackson, Keith & Thompson, Mary
open access

Study of the high-j states in {sup 249}Cm.

Description: The authors have performed the reaction {sup 248}Cm({sup 4}He, {sup 3}He) using 98.5-MeV alpha particles from the IUCF cyclotron to populate high-j states in {sup 249}Cm. A tentative assignment of the K{sub 17/2} component of the 1/2{sup +}[880] Nilsson state has been made.
Date: July 16, 1998
Creator: Ahmad, I.
open access

Large-Signal Injection-Level Spectroscopy of Impurities in Silicon

Description: Deep level defects in silicon are identified by measuring the recombination lifetime as a function of the injection level. The basic models for recombination at deep and shallow centers is developed. The defect used for the theoretical model is the well-known interstitial Fe ion in silicon. Data are presented on silicon samples ranging in defect content from intentionally Fe-doped samples to an ultra-pure float-zone grown sample. These data are analyzed in terms of the injection-level spectrosc… more
Date: October 16, 1998
Creator: Ahrenkiel, R. K. & Johnston, S. W.
open access

Recombination Lifetime of InxGa1-xAs Alloys Used in Thermophotovoltaic Converters

Description: The family of ternary compounds of composition InxGa1-xAs are of considerable interest for thermophotovoltaic energy converters. The recombination lifetimes of the various compositions are critical to the successful application of these materials as efficient converters. Here we will describe experimental results on the composition. In0.53Ga0.47 that is lattice-matched to InP. We will also describe lifetime results on the compositions In0.68Ga0.32As, with bandgap of 0.60 eV to compositions In0.… more
Date: February 16, 1999
Creator: Ahrenkiel, R. K.; Ellingson, R.; Johnston, S.; Webb, J.; Carapella, J. & Wanlass, M.
open access

Setup and Performance of the Rhic Injector Accelerators for the 2005 Run With Copper Ions.

Description: Copper ions for the 2005 run [1] of the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) are accelerated in the Tandem, Booster and AGS prior to injection into RHIC. The setup and performance of these accelerators with copper are reviewed in this paper.
Date: May 16, 2005
Creator: Ahrens, L.; Alessi, J. & Gardner, C. J.
open access

The Luminosity Function of Fermi-detected Flat-Spectrum Radio Quasars

Description: Fermi has provided the largest sample of {gamma}-ray selected blazars to date. In this work we use a complete sample of FSRQs detected during the first year of operation to determine the luminosity function (LF) and its evolution with cosmic time. The number density of FSRQs grows dramatically up to redshift {approx}0.5-2.0 and declines thereafter. The redshift of the peak in the density is luminosity dependent, with more luminous sources peaking at earlier times; thus the LF of {gamma}-ray FSR… more
Date: April 16, 2012
Creator: Ajello, M.; Shaw, M. S.; Romani, R. W.; Dermer, C. D.; Costamante, L.; King, O. G. et al.
open access

Three-Body Breakup Dynamics in Dissociative Recombination

Description: Using the CRYRing Facility in Stockholm Coupled with an MCP-CCD detector, and a differential stopping foil, we have determined dynamic parameters in the three-body dissociative recombination of H<sub>2</sub>O<sup>+</sup>. These include the distribution between the O(<sup>3</sup>P) and O(<sup>1</sup>D) channels, the distribution of H atom recoil energies in the O(<sup>3</sup>P) channel and the distribution of angles between the two departing H atoms.
Date: June 16, 1999
Creator: Al-Khalili, A.; Datz, S.; Derkatch, A.; Larsson, M.; Rosén, S.; Shi, W. et al.
open access

Advanced Compton scattering light source R&D at LLNL

Description: We report the design and current status of a monoenergetic laser-based Compton scattering 0.5-2.5 MeV {gamma}-ray source. Previous nuclear resonance fluorescence results and future linac and laser developments for the source are presented. At MeV photon energies relevant for nuclear processes, Compton scattering light sources are attractive because of their relative compactness and improved brightness above 100 keV, compared to typical 4th generation synchrotrons. Recent progress in accelerator… more
Date: February 16, 2010
Creator: Albert, F.; Anderson, S. G.; Anderson, G.; Betts, S. M.; Chu, T. S.; Gibson, D. J. et al.
open access

The Very Large Hadron Collider

Description: I present some of the current ideas about a Very Large Hadron Collider [1] which could eventually extend the high energy frontier beyond that of the Large Hadron Collider (LHC) or any other machine seriously conceived at this time.
Date: February 16, 1999
Creator: Albrow, Michael G.
open access

Coherent beam-beam effects, theory & observations

Description: Current theoretical understanding of the coherent beam-beam effect as well as its experimental observations are discussed: conditions under which the coherent beambeam modes may appear, possibility of their resonant interaction (coherent resonances), stability of beam-beam oscillations in the presence of external impedances. A special attention is given to the coherent beam-beam modes of finite length bunches: the synchro-betatron coupling is shown to provide reduction in the coherent tuneshift… more
Date: July 16, 2003
Creator: Alexahin, Yuri I
open access

Availability Performance and Considerations for LCLS X-Ray FEL at SLAC

Description: The Linac Coherent Light Source (LCLS) is an X-ray Free Electron Laser (FEL) facility located at the SLAC National Accelerator Laboratory. LCLS has been in operation since spring 2009, and it has completed its 3rd user run. LCLS is the first in its class of X-ray FEL user facilities, and presents different availability challenges compared to storage ring light sources. This paper presents recent availability performance of the FEL as well as factors to consider when defining the operational ava… more
Date: August 16, 2011
Creator: Allen, W. B.; Brachmann, A.; Colocho, W.; Stanek, M. & Warren, J.
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