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["Welcome to Bab's Café, In memory of Barbara Becker"]

Description: Photograph of four people looking at the camera under a white tent pavilion, with a sign, prominently displayed which reads, "Welcome to Bab's Café, In Memory of Barbara Becker" in red letters with flowers and smiley faces patterned around the text. The four people all wear LSR crew t-shirts and are standing in front of two folding tables covered with food-serving dishes and containers. Boxes appear stacked behind the pair to the left.
Date: November 6, 2005
Item Type: Refine your search to only Photograph
Partner: UNT Libraries Special Collections

[Workers together for Mary's baby shower]

Description: A photograph of Multicultural Center workers gathered together for Mary's baby shower. Mary is sitting in front of them and Rushika Patel, Andrea Robledo, Cheylon Brown, and Tracy are among those behind her. There is a Lightweight Travel System baby carrier in front of them and balloons behind them.
Date: January 6, 2005
Creator: University of North Texas. Multicultural Center.
Item Type: Refine your search to only Photograph
Partner: UNT Libraries Special Collections
open access

A First Look at Beam Diagnostics for the Rhic Electron Cooling Project.

Description: High energy electron cooling [1] is essential to meet the luminosity specification for RHIC II [2]. In preparation for electron cooling, an Energy Recovery Linac (ERL) test facility [3] is under construction at BNL. A preliminary description of Diagnostics for the ERL was presented at an earlier workshop [4]. A significant portion of the eCooling Diagnostics will be a simple extension of those developed for the ERL test facility. In this paper we present a preliminary report on eCooling Diagnos… more
Date: June 6, 2005
Creator: Cameron, P.; Ben-Zvi, Ilan; Kewisch, J. & Litvinenko, V.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

The Effects and Possible Origins of Mains Ripple in the Vicinity of the Betatron Spectrum.

Description: With the advent of significant improvement in the sensitivity of observation of the betatron spectrum, the appearance of spectral lines at harmonics of the mains power frequency has been observed in the PS and SPS at CERN, the Tevatron at FNAL, and RHIC at BNL. These lines are potentially problematic for accurate tune tracking and the implementation of tune feedback We discuss the possible origins of these lines, and present data to support our discussion.
Date: June 6, 2005
Creator: Cameron, P.; Gasior, M.; Jones, R. & Tan, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

ADVANCES TOWARDS THE MEASUREMENT AND CONTROL LHC TUNE AND CHROMATICITY

Description: Requirements for tune and chromaticity control in most superconducting hadron machines, and in particular the LHC, are stringent. In order to reach nominal operation, the LHC will almost certainly require feedback on both tune and chromaticity. Experience at RHIC has also shown that coupling control is crucial to successful tune feedback. A prototype baseband phase-locked loop (PLL) tune measurement system has recently been brought into operation at RHIC as part of the US LHC Accelerator Resear… more
Date: June 6, 2005
Creator: Cameron, P.; Cupolo, J.; Degen, C.; Dellapenna, A.; Hoff, L.; Mead, J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

{sup 48}Ti(n,xnpa{gamma}) reaction cross sections using spallation neutrons for E{sub n} = 1 to 20 MeV

Description: {gamma}-ray excitation functions have been measured for the interaction of fast neutrons with {sup 48}Ti (neutron energy from 1 MeV to 250 MeV). The Los Alamos National Laboratory spallation neutron source, at the LANSCE/WNR facility, provided a ''white'' neutron beam which is produced by bombarding a natural W target with a pulsed proton beam. The prompt-reaction {gamma} rays were measured with the large-scale Compton-suppressed Ge spectrometer, GEANIE. Neutron energies were determined by the … more
Date: January 6, 2005
Creator: Dashdorj, D.; Mitchell, G. E.; Garrett, P. E.; Agvaanluvsan, U.; Becker, J. A.; Bernstein, L. A. et al.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

The Surrogate Method - An Indirect Approach to Compound-Nucleus Reactions

Description: An indirect method for determining cross sections for reactions proceeding through a compound nucleus is presented. Exploring indirect approaches for obtaining reaction cross sections is important since a large number of reactions relevant to astrophysics cannot be measured with currently available techniques. Of particular importance are reactions involving unstable nuclei. Some applications of the Surrogate nuclear reactions method are considered and challenges that need to be addressed are o… more
Date: April 6, 2005
Creator: Escher, J; Ahle, L; Bernstein, L; Burke, J; Church, J A; Dietrich, F et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

ELECTROMAGNETIC SIMULATIONS OF HELICAL-BASED ION ACCELERATION STRUCTURES

Description: Helix structures have been proposed [1] for accelerating low energy ion beams using MV/m fields in order to increase the coupling efficiency of the pulsed power system and to tailor the electromagnetic wave propagation speed with the particle beam speed as the beam gains energy. Calculations presented here show the electromagnetic field as it propagates along the helix structure, field stresses around the helix structure (for voltage breakdown determination), optimizations to the helix and driv… more
Date: May 6, 2005
Creator: Nelson, S D; Caporaso, G; Friedman, A; Poole, B R; Briggs, R & Waldron, W
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Exploring heavy-quark energy loss via b-tagging in heavy ion collisions at the LHC

Description: A strategy to study flavor-dependent parton energy loss by tagging heavy quark jets in p+p, p+Pb and Pb+Pb collisions at the LHC is discussed. Estimates for production cross-sections and experimental techniques employed at collider detectors to search for Q{bar Q} jets are presented and a brief evaluation of the capabilities of CMS, ALICE and ATLAS detectors are given.
Date: January 6, 2005
Creator: Klay, J L
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Diode Pumped Alkali Vapor Lasers - A New Pathway to High Beam Quality at High Average Power

Description: Resonance-transition alkali-vapor lasers have only recently been demonstrated [1] but are already attracting considerable attention. Alkali-atom-vapor gain media are among the simplest possible systems known, so there is much laboratory data upon which to base performance predictions. Therefore, accurate modeling is possible, as shown by the zero- free-parameter fits [2] to experimental data on alkali-vapor lasers pumped with Ti:sapphire lasers. The practical advantages of two of the alkali sys… more
Date: May 6, 2005
Creator: Page, R H; Boley, C D; Rubenchik, A M & Beach, R J
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Spin distribution in preequilibrium reactions for 48Ti + n.

Description: Cross section measurements were made of prompt {gamma}-ray production as a function of incident neutron energy on a {sup 48}Ti sample. Partial {gamma}-ray cross sections for transitions in {sup 45-48}Ti, {sup 44-48}Sc, and {sup 42-45}Ca have been determined. Energetic neutrons were delivered by the Los Alamos National Laboratory spallation neutron source located at the LANSCE/WNR facility. The prompt-reaction {gamma} rays were detected with the large-scale Compton-suppressed germanium array for… more
Date: April 6, 2005
Creator: Dashdorj, D
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

The Vetter-Sturtevant Shock Tube Problem in KULL

Description: The goal of the EZturb mix model in KULL is to predict the turbulent mixing process as it evolves from Rayleigh-Taylor, Richtmyer-Meshkov, or Kelvin-Helmholtz instabilities. In this report we focus on an example of the Richtmyer-Meshkov instability (which occurs when a shock hits an interface between fluids of different densities) with the additional complication of reshock. The experiment by Vetter & Sturtevant (VS) [1], involving a Mach 1.50 incident shock striking an air/SF{sub 6} interface,… more
Date: October 6, 2005
Creator: Ulitsky, M S
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

A hybrid method for computing forces on curved dislocations threading to free surfaces

Description: Dislocations threading to free surfaces present a challenge for numerical implementation of traction-free boundary conditions. The difficulty arises when canonical (singular) solutions of dislocation mechanics are used in combination with the Finite Element or Boundary Element (Green's function) methods. A new hybrid method is developed here in which the singular part and the non-singular (regular) part of the image stress are dealt with separately. A special analytical solution for a semi-infi… more
Date: June 6, 2005
Creator: Tang, M; Cai, W; Xu, G & Bulatov, V V
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Exploring Lifetime Effects in Femtoscopy

Description: We investigate the role of lifetime effects from resonances and emission duration tails in femtoscopy at RHIC in two Blast-Wave models. We find the non-Gaussian components compare well with published source imaged data, but the value of R{sub out} obtained from Gaussian fits is not insensitive to the non-Gaussian contributions when realistic acceptance cuts are applied to models.
Date: September 6, 2005
Creator: Brown, D.; Soltz, R.; Newby, J. & Kisiel, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Material dynamics under extreme conditions of pressure and strain rate

Description: Solid state experiments at extreme pressures (10-100 GPa) and strain rates ({approx}10{sup 6}-10{sup 8}s{sup -1}) are being developed on high-energy laser facilities, and offer the possibility for exploring new regimes of materials science. These extreme solid-state conditions can be accessed with either shock loading or with a quasi-isentropic ramped pressure drive. Velocity interferometer measurements establish the high pressure conditions. Constitutive models for solid-state strength under t… more
Date: September 6, 2005
Creator: Remington, Bruce A.; Allen, Patrick; Bringa, Eduaro; Hawreliak, Jim; Ho, Darwin; Lorenz, K. Thomas et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Electron Dynamics of Silicon Surface States: Second-Harmonic HoleBurning on Si(111)7x7

Description: The ultrafast dynamics of electronic excitations of the surface dangling bond states of Si(111) 7 x 7 has been investigated by second harmonic generation as a probe of transient spectral hole burning. Spectral holes induced by a 100 fs pump at {approx_equal} 1.5 eV and their decay are interpreted in terms of electronic dephasing times as short as 15 fs. This fast time scale together with the strong excitation-induced dephasing observed is interpreted in terms of carrier-carrier scattering. In a… more
Date: June 6, 2005
Creator: McGuire, John A.; Raschke, Markus B. & Shen, Yuen-Ron
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Ignition Target Fabrication and Fielding for the National Ignition Facility

Description: Continued advances in the design of ignition targets have stimulating new development paths for target fabrication, with potentially important simplifications for fielding cryogenic ignition targets for the National Ignition Facility. Including graded dopants in ablators as well as optimizing capsule and fuel layer dimensions increase implosion stability. This has led to developments of micron-scale fill tubes to fill and field the targets. Rapid progress has been made in development of the gra… more
Date: October 6, 2005
Creator: Bernat, T. P.; Huang, H.; Nikroo, A.; Stephens, R.; Wilkens, H.; Xu, H. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Effect of Wavefront Error on 10^-7 Contrast Measurements

Description: We have measured a contrast of 6.5 {center_dot} 10{sup -8} from 10-25{lambda}/D in visible light on the Extreme Adaptive Optics testbed using a shaped pupil for diffraction suppression. The testbed was designed with a minimal number of high-quality optics to ensure low wavefront error and uses a phase shifting diffraction interferometer for metrology. This level of contrast is within the regime needed for imaging young Jupiter-like planets, a primary application of high-contrast imaging. We hav… more
Date: October 6, 2005
Creator: Evans, J. W.; Sommargren, G.; Macintosh, B.; Severson, S. & Dillon, D.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Localized Corrosion of Alloy 22 -Fabrication Effects-FY05 Summary Report

Description: This report deals with the impact of fabrication processes on the localized corrosion behavior of Alloy 22 (N06022). The four fabrication processes that were analyzed are: (1) Surface stress mitigation of final closure weld, (2) Manufacturing of the mockup container, (3) Black annealing of the container and (4) Use of different heats of Alloy 22 for container fabrication. Immersion and Electrochemical tests performed in the laboratory are generally aggressive and do not represent actual reposit… more
Date: October 6, 2005
Creator: Rebak, R B
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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