REVISED INDEPENDENT VERIFICATION SURVEY OF A AND B RADIOACTIVE WASTE TRANSFER LINES TRENCH BROOKHAVEN NATIONAL LABORATORY (open access)

REVISED INDEPENDENT VERIFICATION SURVEY OF A AND B RADIOACTIVE WASTE TRANSFER LINES TRENCH BROOKHAVEN NATIONAL LABORATORY

REVISED INDEPENDENT VERIFICATION SURVEY OF THE A AND B RADIOACTIVE WASTE TRANSFER LINES TRENCH, BROOKHAVEN NATIONAL LABORATORY 5062-SR-01-1
Date: February 10, 2010
Creator: Weaver, P. C.
Object Type: Report
System: The UNT Digital Library
Extreme Ultraviolet Laser-based Table-top Aerial Image Metrology of Lithographic Masks (open access)

Extreme Ultraviolet Laser-based Table-top Aerial Image Metrology of Lithographic Masks

We report the first at-wavelength line edge roughness measurements of patterned EUV lithography masks realized using a table-top aerial imaging system based on a table-top {lambda}=13.2 laser.
Date: February 10, 2010
Creator: Brizuela, F.; Carbajo, S.; Sakdinawat, A.; Wang, Y.; Alessi, D.; Martz, D. et al.
Object Type: Article
System: The UNT Digital Library
R&D ERL: G5 test and commissioning plan (open access)

R&D ERL: G5 test and commissioning plan

Gun-to-5-cell cavity (G5) setup (Fig 1-2) can be considered as the first stage of the final BNL ERL design. The goal of the G5 setup is to test critical ERL components with the beam and characterize the beam produced by the gun. Also, this test will be used to assess effectiveness of the zigzag merger, which will be installed later in the ERL setup. The major components under the test will include the SRF gun, the five-cell SRF cavity, vacuum components, parts of the control and diagnostic systems. G5 is designed to measure the following beam parameters: (1) projected bunch emittance (?) and Twiss parameters ({alpha}, {beta}); (2) slice emittance; (3) bunch length; and (4) longitudinal and transverse halo.
Date: February 10, 2010
Creator: Kayran, D. & Pozdeyev, E.
Object Type: Report
System: The UNT Digital Library
317/319 Phytoremediation site monitoring report - 2009 growing season : final report. (open access)

317/319 Phytoremediation site monitoring report - 2009 growing season : final report.

In 1999, Argonne National Laboratory (Argonne) designed and installed a series of engineered plantings consisting of a vegetative cover system and approximately 800 hybrid poplars and willows rooting at various predetermined depths. The plants were installed using various methods including Applied Natural Science's TreeWell{reg_sign} system. The goal of the installation was to protect downgradient surface and groundwater by intercepting the contaminated groundwater with the tree roots, removing moisture from the upgradient soil area, reducing water infiltration, preventing soil erosion, degrading and/or transpiring the residual volatile organic compounds (VOCs), and removing tritium from the subsoil and groundwater. This report presents the results of the monitoring activities conducted by Argonne's Energy Systems (ES) Division in the growing season of 2009. Monitoring of the planted trees began soon after the trees were installed in 1999 and has been conducted every summer since then. As the trees grew and consolidated their growth into the contaminated soil and groundwater, their exposure to the contaminants was progressively shown through tissue sampling. During the 2009 sampling campaign, VOC concentrations found in the French Drain area were in general consistent with or slightly lower than the 2008 results. Additionally, closely repeated, stand wide analyses showed contaminant fluctuations that …
Date: February 10, 2010
Creator: Negri, C .N.; Benda, P. L.; Gopalakrishnan, G. & Systems, Energy
Object Type: Report
System: The UNT Digital Library
BPM Breakdown Potential in the PEP-II B-factory Storage Ring Collider (open access)

BPM Breakdown Potential in the PEP-II B-factory Storage Ring Collider

High current B-Factory BPM designs incorporate a button type electrode which introduces a small gap between the button and the beam chamber. For achievable currents and bunch lengths, simulations indicate that electric potentials can be induced in this gap which are comparable to the breakdown voltage. This study characterizes beam induced voltages in the existing PEP-II storage ring collider BPM as a function of bunch length and beam current.
Date: February 10, 2010
Creator: Weathersby, Stephen & Novokhatski, Alexander
Object Type: Article
System: The UNT Digital Library
HOM Sensitivity in the PEP-II HER Vacuum Chamber (open access)

HOM Sensitivity in the PEP-II HER Vacuum Chamber

Synchrotron radiation is the main source of vacuum chamber heating in the PEP-II storage ring collider. This heating is reduced substantially as lattice energy is lowered. Energy scans over {Upsilon} energy states were performed by varying the high energy ring (HER) lattice energy at constant gap voltage and frequency. We observed unexpected temperature rise at particular locations when HER lattice energy was lowered from 8.6 GeV ({Upsilon}(3S)) to 8.0 GeV ({Upsilon}(2S)) while most other temperatures decreased. Bunch length measurements reveal a shorter bunch at the lower energy. The shortened bunch overheated a beam position monitoring electrode causing a vacuum breach. We explain the unexpected heating as a consequence of increased higher order mode (HOM) power generated by a shortened bunch. In this case, temperature rise helps to identify HOM sources and HOM sensitive vacuum chamber elements. Reduction of gap voltage helps to reduce this unexpected heating.
Date: February 10, 2010
Creator: Weathersby, Stephen; Novokhatski, Alexander & Sullivan, Mike
Object Type: Article
System: The UNT Digital Library
An Exact SU(2) Symmetry and Persistent Spin Helix in a Spin-Orbit Coupled System (open access)

An Exact SU(2) Symmetry and Persistent Spin Helix in a Spin-Orbit Coupled System

Spin-orbit coupled systems generally break the spin rotation symmetry. However, for a model with equal Rashba and Dresselhauss coupling constant (the ReD model), and for the [110] Dresselhauss model, a new type of SU(2) spin rotation symmetry is discovered. This symmetry is robust against spin-independent disorder and interactions, and is generated by operators whose wavevector depends on the coupling strength. It renders the spin lifetime infinite at this wavevector, giving rise to a Persistent Spin Helix (PSH). We obtain the spin fluctuation dynamics at, and away, from the symmetry point, and suggest experiments to observe the PSH.
Date: February 10, 2010
Creator: Bernevig, Andrei
Object Type: Article
System: The UNT Digital Library
Beam Fields in an Integrated Cavity, Coupler and Window Configuration (open access)

Beam Fields in an Integrated Cavity, Coupler and Window Configuration

In a multi-bunch high current storage ring, beam generated fields couple strongly into the RF cavity coupler structure when beam arrival times are in resonance with cavity fields. In this study the integrated effect of beam fields over several thousand RF periods is simulated for the complete cavity, coupler, window and waveguide system of the PEP-II B-factory storage ring collider. We show that the beam generated fields at frequencies corresponding to several bunch spacings for this case gives rise to high field strength near the ceramic window which could limit the performance of future high current storage rings such as PEP-X or Super B-factories.
Date: February 10, 2010
Creator: Weathersby, Stephen & Novokhatski, Alexander
Object Type: Article
System: The UNT Digital Library
Robust Algorithm for Computing Statistical Stark Broadening of Spectral Lines (open access)

Robust Algorithm for Computing Statistical Stark Broadening of Spectral Lines

A method previously developed to solve large-scale linear systems is applied to statistical Stark broadened line shape calculations. The method is formally exact, numerically stable, and allows optimization of the integration over the quasi-static field to assure numerical accuracy. Furthermore, the method does not increase the computational effort and often can decrease it compared to the conventional approach.
Date: February 10, 2010
Creator: Iglesias, C A & Sonnad, V
Object Type: Article
System: The UNT Digital Library
Improving Reproducibility in Sputtered Beryllium and Graded Copper Doped Beryllium Capsules (open access)

Improving Reproducibility in Sputtered Beryllium and Graded Copper Doped Beryllium Capsules

None
Date: February 10, 2010
Creator: Youngblood, K.; Hayes, J.; Moreno, K.; Nikoo, A.; Xu, H.; Alford, C. et al.
Object Type: Article
System: The UNT Digital Library
Modeling Blood Flow in a Tilted IVC Filter: Does Tilt Adversely Affect Hemodynamics? (open access)

Modeling Blood Flow in a Tilted IVC Filter: Does Tilt Adversely Affect Hemodynamics?

None
Date: February 10, 2010
Creator: Singer, M. A. & Wang, S. L.
Object Type: Article
System: The UNT Digital Library
Determination of rotatable and frozen CoO spins and their relationship to exchange bias in CoO/Fe/Ag(001) (open access)

Determination of rotatable and frozen CoO spins and their relationship to exchange bias in CoO/Fe/Ag(001)

The exchange bias of epitaxially grown CoO/Fe/Ag(001) was investigated using X-ray Magnetic Circular Dichroism (XMCD) and X-ray Magnetic Linear Dichroism (XMLD) techniques. A direct XMLD measurement on the CoO layer during the Fe magnetization reversal shows that the CoO compensated spins are rotatable at thinner thickness and frozen, i.e. fixed in direction to the lattice, at larger thickness. By a quantitative determination of the rotatable and frozen CoO spins as a function of the CoO film thickness, we find the remarkable result that the exchange bias is well established before frozen spins are detectable in the CoO film, contrary to the common assumption that the majority of antiferromagnetic spins need to be frozen to generate the exchange bias. We further show that the rotatable/frozen CoO spins are uniformly distributed in the CoO film.
Date: February 10, 2010
Creator: Wu, J.; Park, J.; Kim, W.; Arenholz, E.; Liberati, M.; Scholl, A. et al.
Object Type: Article
System: The UNT Digital Library
A moving target: responding to magnetic and structural disorder in lanthanide- and actinide-based superconductors (open access)

A moving target: responding to magnetic and structural disorder in lanthanide- and actinide-based superconductors

The effects of various chemical substitutions and induced lattice disorder in the Ce- and Pu-based 115 superconductors are reviewed, with particular emphasis on results from x-ray absorption fine structure (XAFS) measurements. The PuCoGa{sub 5} system offers the opportunity to follow changes in magnetic and electronic properties due to lattice disorder as a function of time in the same samples, in addition to the more traditional approach of perturbing the superconducting state through chemical substitutions. The reviewed work establishes a baseline for such future studies by determining the intrinsic lattice order in the 115 system, successfully understanding disorder as introduced through chemical substitutions in the Ce-based 115s, and beginning to explore the surprisingly large role of self-irradiation damage directly on the PuCoGa{sub 5} lattice. These studies lay the foundation for the harder future work toward measuring chemical substitutions in PuCoGa{sub 5}, correlating effects with non-Fermi liquid behavior, and obtaining a better structural picture of the distortions induced by {alpha}-decay of the plutonium nucleus.
Date: February 10, 2010
Creator: Booth, Corwin H.; Bauer, Eric D. & Mitchel, Jeremy N.
Object Type: Article
System: The UNT Digital Library
Effect of NiO spin orientation on the magnetic anisotropy of the Fe film in epitaxially grown Fe/NiO/Ag(001) and Fe/NiO/MgO(001) (open access)

Effect of NiO spin orientation on the magnetic anisotropy of the Fe film in epitaxially grown Fe/NiO/Ag(001) and Fe/NiO/MgO(001)

Single crystalline Fe/NiO bilayers were epitaxially grown on Ag(001) and on MgO(001), and investigated by Low Energy Electron Diffraction (LEED), Magneto-Optic Kerr Effect (MOKE), and X-ray Magnetic Linear Dichroism (XMLD). We find that while the Fe film has an in-plane magnetization in both Fe/NiO/Ag(001) and Fe/NiO/MgO(001) systems, the NiO spin orientation changes from in-plane direction in Fe/NiO/Ag(001) to out-of-plane direction in Fe/NiO/MgO(001). These two different NiO spin orientations generate remarkable different effects that the NiO induced magnetic anisotropy in the Fe film is much greater in Fe/NiO/Ag(001) than in Fe/NiO/MgO(001). XMLD measurement shows that the much greater magnetic anisotropy in Fe/NiO/Ag(001) is due to a 90{sup o}-coupling between the in-plane NiO spins and the in-plane Fe spins.
Date: February 10, 2010
Creator: Kim, W.; Jin, E.; Wu, J.; Park, J.; Arenholz, E.; Scholl, A. et al.
Object Type: Article
System: The UNT Digital Library