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in publisher: "SLAC National Accelerator Laboratory"  
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Galaxy Mergers with Adaptive Mesh Refinement: Star Formation and Hot Gas Outflow

Description: In hierarchical structure formation, merging of galaxies is frequent and known to dramatically affect their properties. To comprehend these interactions high-resolution simulations are indispensable because of the nonlinear coupling between pc and Mpc scales. To this end, we present the first adaptive mesh refinement (AMR) simulation of two merging, low mass, initially gas-rich galaxies (1.8 x 10{sup 10} M{sub {circle_dot}} each), including star formation and feedback. With galaxies resolved by… more
Date: June 22, 2011
Creator: Kim, Ji-hoon; /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Wise, John H.; /NASA, Goddard; Abel, Tom & /KIPAC, Menlo Park /Stanford U., Phys. Dept.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Analytical analysis of longitudinal space charge effects for a bunched beam with radial dependence

Description: The longitudinal space-charge (LSC) force can be a major cause of the microbunching instability in the linac for an x-ray free-electron laser. In this paper, the LSC-induced beam modulation is studied using an integral equation approach that takes into account the transverse (radial) variation of the LSC field for both the coasting-beam limit and a bunched beam. Variation of the beam energy and the transverse beam size is also incorporated. We discuss the validity of this approach and compare i… more
Date: June 16, 2008
Creator: Wu, Juhao; Huang, Zhirong & Emma, Paul
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Slowly Varying Dilaton Cosmologies and Their Field Theory Duals

Description: We consider a deformation of the AdS{sub 5} x S{sup 5} solution of IIB supergravity obtained by taking the boundary value of the dilaton to be time dependent. The time dependence is taken to be slowly varying on the AdS scale thereby introducing a small parameter {epsilon}. The boundary dilaton has a profile which asymptotes to a constant in the far past and future and attains a minimum value at intermediate times. We construct the sugra solution to first non-trivial order in {epsilon}, and fin… more
Date: June 28, 2011
Creator: Awad, Adel; Das, Sumit R.; Ghosh, Archisman; Oh, Jae-Hyuk & Trivedi, Sandip P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Optics Tuning Knobs for Facet

Description: FACET is a new facility under construction at the SLAC National Accelerator Laboratory. The FACET beam line is designed to provide 23 GeV tightly focused and compressed electron and positron bunches for beam driven plasma wakefield acceleration research and other experiments. Achieving optimal beam parameters for various experimental conditions requires the optics capability for tuning in a sufficiently wide range. This will be achieved by using optics tuning systems (knobs). Design of such sys… more
Date: June 2, 2011
Creator: Nosochkov, Yuri; Hogan, Mark J. & Wittmer, Walter
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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COMPENSATION OF DETECTOR SOLENOID IN SUPER-B

Description: The SUPER-B detector solenoid has a strong 1.5 T field in the Interaction Region (IR) area, and its tails extend over the range of several meters. The main effect of the solenoid field is coupling of the horizontal and vertical betatron motion which must be corrected in order to preserve the small design beam size at the Interaction Point. The additional effects are orbit and dispersion caused by the angle between the solenoid and beam trajectories. The proposed correction system provides local… more
Date: June 2, 2011
Creator: Nosochkov, Yuri; Bertsche, Kirk & Sullivan, Michael
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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On the Origin of the Mass-Metallicity Relation for GRB Host Galaxies

Description: We investigate the nature of the mass-metallicity (M-Z) relation for long gamma-ray burst (LGRB) host galaxies. Recent studies suggest that the M-Z relation for local LGRB host galaxies may be systematically offset towards lower metallicities relative to the M-Z relation defined by the general star forming galaxy (SDSS) population. The nature of this offset is consistent with suggestions that low metallicity environments may be required to produce high mass progenitors, although the detection o… more
Date: June 2, 2011
Creator: Kocevski, Daniel & West, Andrew A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A Terrestrial Search for Dark Contents of the Vacuum, Such as Dark Energy, Using Atom Interferometry

Description: We describe the theory and first experimental work on our concept for searching on earth for the presence of dark contents of the vacuum (DCV) using atom interferometry. Specifically, we have in mind any DCV that has not yet been detected on a laboratory scale, but which might manifest itself as dark energy on the cosmological scale. The experimental method uses two atom interferometers to cancel the effect of earth's gravity and diverse noise sources. It depends upon two assumptions: first, th… more
Date: June 11, 2012
Creator: Adler, Ronald J.; /Stanford U., HEPL /San Francisco State U.; Muller, Holger; /UC, Berkeley; Perl, Martin L. & /KIPAC, Menlo Park /SLAC
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Development of a Navigator and Imaging Techniques for the Cryogenic Dark Matter Search Detectors

Description: This project contributes to the detection of flaws in the germanium detectors for the Cryogenic Dark Matter Search (CDMS) experiment. Specifically, after imaging the detector surface with a precise imaging and measuring device, they developed software to stitch the resulting images together, applying any necessary rotations, offsets, and averaging, to produce a smooth image of the whole detector that can be used to detect flaws on the surface of the detector. These images were also tiled approp… more
Date: June 22, 2011
Creator: Wilen, Chris & /Carleton Coll. /KIPAC, Menlo Park
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Radiation Transport Calculations and Simulations

Description: This article is an introduction to the Monte Carlo method as used in particle transport. After a description at an elementary level of the mathematical basis of the method, the Boltzmann equation and its physical meaning are presented, followed by Monte Carlo integration and random sampling, and by a general description of the main aspects and components of a typical Monte Carlo particle transport code. In particular, the most common biasing techniques are described, as well as the concepts of … more
Date: June 30, 2011
Creator: Fasso, Alberto & Ferrari, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Gluons and the Quark Sea at High Energies: Distributions, Polarization, Tomography

Description: This report on the science case for an Electron-Ion Collider (EIC) is the result of a ten-week program at the Institute for Nuclear Theory (INT) in Seattle (from September 13-November 19, 2010), motivated by the need to develop a strong case for the continued study of the QCD description of hadron structure in the coming decades. Hadron structure in the valence quark region will be studied extensively with the Jefferson Lab 12 GeV science program, the subject of an INT program the previous year… more
Date: June 7, 2012
Creator: Boer, Daniel; Diehl, Markus; Milner, Richard; Venugopalan, Raju; Vogelsang, Werner; Kaplan, David et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Stable Non-Supersymmetric Throats in String Theory

Description: We construct a large class of non-supersymmetric AdS-like throat geometries in string theory by taking non-supersymmetric orbifolds of supersymmetric backgrounds. The scale of SUSY breaking is the AdS radius, and the dual field theory has explicitly broken supersymmetry. The large hierarchy of energy scales in these geometries is stable. We establish this by showing that the dual gauge theories do not have any relevant operators which are singlets under the global symmetries. When the geometrie… more
Date: June 28, 2011
Creator: Kachru, Shamit; Simic, Dusan; /Stanford U., ITP /SLAC /Santa Barbara, KITP; Trivedi, Sandip P. & /Tata Inst. /Stanford U., ITP /SLAC
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Laser Assisted Emittance Transfer for Storage Ring Lasing

Description: In modern storage rings the transverse emittance of electron beams can be comparable to that from state-of-art photoinjectors, but the intrinsic low peak current and large energy spread pre-cludes the possibility of realizing short-wavelength high-gain free electron lasers (FELs) in storage rings. In this note I propose a technique to significantly increase beam peak current without greatly increasing beam energy spread, which is achieved by transferring part of the longitudinal emittance to tr… more
Date: June 1, 2011
Creator: Xiang, Dao
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

A 4 to 0.1 nm FEL Based on the SLAC Linac

Description: The author show that using existing electron gun technology and a high energy linac like the one at SLAC, it is possible to build a Free Electron Laser operating around the 4 nm water window. A modest improvement in the gun performance would further allow to extend the FEL to the 0.1 nm region. Such a system would produce radiation with a brightness many order of magnitude above that of any synchrotron radiation source, existing or under construction, with laser power in the multigawatt region … more
Date: June 5, 2012
Creator: Pellegrini, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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New Technique for Speciation of Uranium in Sediments Following Acetate-Stimulated Bioremediation

Description: Acetate-stimulated bioremediation is a promising new technique for sequestering toxic uranium contamination from groundwater. The speciation of uranium in sediments after such bioremediation attempts remains unknown as a result of low uranium concentration, and is important to analyzing the stability of sequestered uranium. A new technique was developed for investigating the oxidation state and local molecular structure of uranium from field site sediments using X-Ray Absorption Spectroscopy (X… more
Date: June 22, 2011
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Comparing the Calibration and Simulation Data of the Cryogenic Dark Matter Search

Description: The Cryogenic Dark Matter Search, or CDMS, collaboration is preparing a new experiment called SuperCDMS. CDMS uses Germanium detectors to attempt the direct detection of dark matter. To do this, they measure the ionization and heat produced during an event where a WIMP scatters off of germanium crystal lattice. To prepare for the experiment the detectors are calibrated with various radioactive sources. The response of the detectors is also modeled by a Monte Carlo simulation. These simulations … more
Date: June 22, 2011
Creator: DiFranzo, Anthony & /SLAC, /Rensselaer Poly.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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