Cascaded Modulator-chicane Modules for Optical Manipulation of Relativistic Electron Beams (open access)

Cascaded Modulator-chicane Modules for Optical Manipulation of Relativistic Electron Beams

None
Date: February 7, 2013
Creator: Hemsing, Erik & Xiang, Dao
System: The UNT Digital Library
Echo-Enabled X-Ray Vortex Generation (open access)

Echo-Enabled X-Ray Vortex Generation

None
Date: February 7, 2013
Creator: Hemsing, E. & Marinelli, A.
System: The UNT Digital Library
Directed Relation Graph with Expert Knowledge for Skeletal Mechanism Reduction (open access)

Directed Relation Graph with Expert Knowledge for Skeletal Mechanism Reduction

None
Date: February 7, 2011
Creator: Lu, T; Plomer, M; Luo, Z; Sarathy, S M; Pitz, W J; Som, S et al.
System: The UNT Digital Library
Spin Physics at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC) (open access)

Spin Physics at A Fixed-Target ExpeRiment at the LHC (AFTER@LHC)

None
Date: February 7, 2013
Creator: Rakotozafindrabe, A.; /DAPNIA, Saclay; Anselmino, M.; /INFN, Turin; Arnaldi, R.; /INFN, Turin et al.
System: The UNT Digital Library
Prospectives for a Fixed-Target ExperRment at the LHC: AFTER@LHC (open access)

Prospectives for a Fixed-Target ExperRment at the LHC: AFTER@LHC

None
Date: February 7, 2013
Creator: Lansberg, J.P.; Chambert, V.; Didelez, J.P.; Genolini, B.; Hadjidakis, C.; Lorce, C. et al.
System: The UNT Digital Library
A Project to Design and Build the Magnets for a New Test Beamline, the ATF2, at KEK (open access)

A Project to Design and Build the Magnets for a New Test Beamline, the ATF2, at KEK

In order to achieve the high luminosity required at the proposed International Linear Collider (ILC), it is critical to focus the beams to nanometer size with the ILC Beam Delivery System, and to maintain the beams collisions with a nanometer-scale stability. To establish the technologies associated with this ultra-high precision beam handling, a special beamline has been designed and built as an extension of the existing extraction beamline of the Accelerator Test Facility at KEK, Japan. The ATF provides an adequate ultra-low emittance electron beam that is comparable to the ILC requirements; the ATF2 mimics the ILC final focus system to create a tightly focused, stable beam. There are 37 magnets in the ATF2, 29 quadrupoles, 5 sextupoles and 3 bends. These magnets had to be acquired in a short time and at minimum cost, which led to various acquisition strategies; but nevertheless they had to meet strict requirements on integrated strength, physical dimensions, compatibility with existing magnet movers and beam position monitors, mechanical stability and field stability and quality. This paper will describe how 2 styles of quadrupoles, 2 styles of sextupoles, one dipole style and their supports were designed, fabricated, refurbished or modified, measured and aligned by a …
Date: February 7, 2011
Creator: Spencer, Cherrill M.; /slac; Sugahara, Ryuhei; Masuzawa, Mika; /KEK, Tsukuba; Bolzon, Benoit et al.
System: The UNT Digital Library
New Perspectives for QCD Physics at the LHC (open access)

New Perspectives for QCD Physics at the LHC

I review a number of topics where conventional wisdom relevant to hadron physics at the LHC has been challenged. For example, the initial-state and final-state interactions of the quarks and gluons entering perturbative QCD hard-scattering subprocesses lead to the breakdown of traditional concepts of factorization and universality for transverse-momentum-dependent observables at leading twist. These soft-gluon rescattering effect produce single-spin asymmetries, the breakdown of the Lam-Tung relation in Drell-Yan reactions, as well as diffractive deep inelastic scattering, The antishadowing of nuclear structure functions is predicted to depend on the flavor quantum numbers of each quark and antiquark. Isolated hadrons can be produced at large transverse momentum directly within a hard higher-twist QCD subprocess, rather than from jet fragmentation, even at the LHC. Such 'direct' processes can explain the observed deviations from pQCD predictions of the power-law fall-off of inclusive hadron cross sections as well as the 'baryon anomaly' seen in high-centrality heavy-ion collisions at RHIC. The intrinsic charm contribution to the proton structure function at high x can explain the large rate for high p{sub T} photon plus charm-jet events observed at the Tevatron and imply a large production rate for charm and bottom jets at high p{sub T} at the …
Date: February 7, 2011
Creator: Brodsky, Stanley J. & /SLAC /Stanford U. /Southern Denmark U., CP3-Origins
System: The UNT Digital Library
CP Violation and Mixing in Charm Meson Decays from BaBar (open access)

CP Violation and Mixing in Charm Meson Decays from BaBar

Mixing and CP violation in charm meson decays provide a unique probe of possible physics beyond the standard model. In this paper, we give a brief review of the current measurements from the BABAR experiment.
Date: February 7, 2011
Creator: Chen, Chunhui & U., /Iowa State
System: The UNT Digital Library
Measuring the Magnetic Center Behavior of an ILC Superconducting Quadrupole Prototype (open access)

Measuring the Magnetic Center Behavior of an ILC Superconducting Quadrupole Prototype

The main linacs of the proposed International Linear Collider (ILC) consist of superconducting cavities operated at 2K. The accelerating cavities are contained in a contiguous series of cryogenic modules that also house the main linac quadrupoles, thus the quadrupoles also need to be superconducting. In an early ILC design, these magnets are about 0.6 m long, have cos (2{theta}) coils, and operate at constant field gradients up to 60 T/m. In order to preserve the small beam emittances in the ILC linacs, the e+ and e- beams need to traverse the quadrupoles near their magnetic centers. A quadrupole shunting technique is used to measure the quadrupole alignment with the beams; this process requires the magnetic centers move by no more than about 5 micrometers when their strength is changed. To determine if such tight stability is achievable in a superconducting quadrupole, we at SLAC measured the magnetic center motions in a prototype ILC quadrupole built at CIEMAT in Spain. A rotating coil technique was used with a better than 0.1 micrometer precision in the relative field center position, and less than a 2 micrometer systematic error over 30 minutes. This paper describes the warm-bore cryomodule that houses the quadrupole in …
Date: February 7, 2011
Creator: Spencer, Cherrill M.; Adolphsen, Chris; Berndt, Martin; Jensen, David R.; Rogers, Ron; Sheppard, John C. et al.
System: The UNT Digital Library
OPERATIONS REVIEW OF THE SAVANNAH RIVER SITE INTEGRATED SALT DISPOSITION PROCESS - 11327 (open access)

OPERATIONS REVIEW OF THE SAVANNAH RIVER SITE INTEGRATED SALT DISPOSITION PROCESS - 11327

The Savannah River Site (SRS) is removing liquid radioactive waste from its Tank Farm. To treat waste streams that are low in Cs-137, Sr-90, and actinides, SRS developed the Actinide Removal Process and implemented the Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU). The Actinide Removal Process contacts salt solution with monosodium titanate to sorb strontium and select actinides. After monosodium titanate contact, the resulting slurry is filtered to remove the monosodium titanate (and sorbed strontium and actinides) and entrained sludge. The filtrate is transferred to the MCU for further treatment to remove cesium. The solid particulates removed by the filter are concentrated to {approx} 5 wt %, washed to reduce the sodium concentration, and transferred to the Defense Waste Processing Facility for vitrification. The CSSX process extracts the cesium from the radioactive waste using a customized solvent to produce a Decontaminated Salt Solution (DSS), and strips and concentrates the cesium from the solvent with dilute nitric acid. The DSS is incorporated in grout while the strip acid solution is transferred to the Defense Waste Processing Facility for vitrification. The facilities began radiological processing in April 2008 and started processing of the third campaign ('MarcoBatch 3') of waste in June …
Date: February 7, 2011
Creator: Peters, T.; Poirier, M.; Fondeur, F.; Fink, S.; Brown, S. & Geeting, M.
System: The UNT Digital Library
Three years of Swift/BAT Survey of AGN: Reconciling Theory and Observations? (open access)

Three years of Swift/BAT Survey of AGN: Reconciling Theory and Observations?

It is well accepted that unabsorbed as well as absorbed AGN are needed to explain the nature and the shape of the Cosmic X-ray background, even if the fraction of highly absorbed objects (dubbed Compton-thick sources) substantially still escapes detection. We derive and analyze the absorption distribution using a complete sample of AGN detected by Swift-BAT in the first three years of the survey. The fraction of Compton-thick AGN represents only 4.6% of the total AGN population detected by Swift-BAT. However, we show that once corrected for the bias against the detection of very absorbed sources the real intrinsic fraction of Compton-thick AGN is 20{sub -6}{sup +9}%. We proved for the first time (also in the BAT band) that the anti-correlation of the fraction of absorbed AGN and luminosity it tightly connected to the different behavior of the luminosity functions (XLFs) of absorbed and unabsorbed AGN. This points towards a difference between the two subsamples of objects with absorbed AGN being, on average, intrinsically less luminous than unobscured ones. Moreover the XLFs show that the fraction of obscured AGN might also decrease at very low luminosity. This can be successfully interpreted in the framework of a disk cloud outflow scenario …
Date: February 7, 2011
Creator: Burlon, D.; /Garching, Max Planck Inst., MPE; Ajello, M.; /SLAC /KIPAC, Menlo Park; Greiner, J.; /Garching, Max Planck Inst., MPE et al.
System: The UNT Digital Library
Advances in Parallel Electromagnetic Codes for Accelerator Science and Development (open access)

Advances in Parallel Electromagnetic Codes for Accelerator Science and Development

Over a decade of concerted effort in code development for accelerator applications has resulted in a new set of electromagnetic codes which are based on higher-order finite elements for superior geometry fidelity and better solution accuracy. SLAC's ACE3P code suite is designed to harness the power of massively parallel computers to tackle large complex problems with the increased memory and solve them at greater speed. The US DOE supports the computational science R&D under the SciDAC project to improve the scalability of ACE3P, and provides the high performance computing resources needed for the applications. This paper summarizes the advances in the ACE3P set of codes, explains the capabilities of the modules, and presents results from selected applications covering a range of problems in accelerator science and development important to the Office of Science.
Date: February 7, 2011
Creator: Ko, Kwok; Candel, Arno; Ge, Lixin; Kabel, Andreas; Lee, Rich; Li, Zenghai et al.
System: The UNT Digital Library
SLAC Linac Preparations for FACET (open access)

SLAC Linac Preparations for FACET

The SLAC 3km linear electron accelerator has been cut at the two-thirds point to provide beams to two independent programs. The last third provides the electron beam for the Linac Coherent Light Source (LCLS), leaving the first two-thirds available for FACET, the new experimental facility for accelerator science and test beams. In this paper, we describe this separation and projects to prepare the linac for the FACET experimental program.
Date: February 7, 2011
Creator: Erickson, R.; Bentson, L.; Kharakh, D.; Owens, A.; Schuh, P.; Seeman, J. et al.
System: The UNT Digital Library
A Different Look at Dark Energy and the Time Variation of Fundamental Constants (open access)

A Different Look at Dark Energy and the Time Variation of Fundamental Constants

This paper makes the simple observation that a fundamental length, or cutoff, in the context of Friedmann-Lemaitre-Robertson-Walker (FRW) cosmology implies very different things than for a static universe. It is argued that it is reasonable to assume that this cutoff is implemented by fixing the number of quantum degrees of freedom per co-moving volume (as opposed to a Planck volume) and the relationship of the vacuum-energy of all of the fields in the theory to the cosmological constant (or dark energy) is re-examined. The restrictions that need to be satisfied by a generic theory to avoid conflicts with current experiments are discussed, and it is shown that in any theory satisfying these constraints knowing the difference between w and minus one allows one to predict w. It is argued that this is a robust result and if this prediction fails the idea of a fundamental cutoff of the type being discussed can be ruled out. Finally, it is observed that, within the context of a specific theory, a co-moving cutoff implies a predictable time variation of fundamental constants. This is accompanied by a general discussion of why this is so, what are the strongest phenomenological limits upon this predicted variation, …
Date: February 7, 2011
Creator: Weinstein, Marvin
System: The UNT Digital Library
Direct Probes of Linearly Polarized Gluons inside Unpolarized Hadrons (open access)

Direct Probes of Linearly Polarized Gluons inside Unpolarized Hadrons

We show that the unmeasured distribution of linearly polarized gluons inside unpolarized hadrons can be directly probed in jet or heavy quark pair production both in electron-hadron and hadron-hadron collisions. We present expressions for the simplest cos 2{phi} asymmetries and estimate their maximal value in the particular case of electron-hadron collisions. Measurements of the linearly polarized gluon distribution in the proton should be feasible in future EIC or LHeC experiments.
Date: February 7, 2011
Creator: Boer, Daniel; Brodsky, Stanley J.; Mulders, Piet J. & Pisano, Cristian
System: The UNT Digital Library
Study of \Bpilnu and \Brholnu decays and determination of \Vub at \babar (open access)

Study of \Bpilnu and \Brholnu decays and determination of \Vub at \babar

The authors report a measurement of the branching fractions for B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu} and B{sup 0} {yields} {rho}{sup -}{ell}{sup +}{nu} decays using charged and neutral B decays with isospin constraints. They find {beta}(B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu}) = (1.41 {+-} 0.05 {+-} 0.07) x 10{sup -4}, and {beta}(B{sup 0} {yields} {rho}{sup -}{ell}{sup +}{nu}) = (1.75 {+-} 0.15 {+-} 0.27) x 10{sup -4}, where the first error is statistical and the second is systematic. They measure {Delta}{beta}/{Delta}q{sup 2}, with 6 q{sup 2} bins for B{sup 0} {yields} {pi}{sup -}{ell}{sup +}{nu} and 3 q{sup 2} bins for B{sup 0} {yields} {rho}{sup -}{ell}{sup +}{nu}, and compare the distributions in data with theoretical predictions for the form factors. They use these branching fractions and form-factor calculations to determine |V{sub ub}|. Based on a combined fit to the FNAL/MILC lattice QCD calculation and data over the full q{sup 2} range, they find |V{sub ub}| = (2.95 {+-} 0.31) x 10{sup -3}.
Date: February 7, 2011
Creator: Wulsin, H.Wells
System: The UNT Digital Library
Naturalness from Runaways in Direct Mediation (open access)

Naturalness from Runaways in Direct Mediation

Postulating that the NMSSM singlet is a meson of a microscopic confining theory opens up new model-building possibilities. Based on this, we construct calculable models of direct mediation that solve the {mu}/B{mu} problem and simultaneously lead to realistic phenomenology. The singlet that couples to the Higgs fields develops a runaway produced by soft interactions, then stabilized by a small superpotential perturbation. The mechanism is first realized in an O'Raifeartaigh model of direct gauge mediation with metastable supersymmetry breaking. Focusing then on the microscopic theory, we argue that super QCD with massless and massive flavors in the free magnetic phase gives rise to this dynamics in the infrared. A deformation of the SQCD superpotential leads to large spontaneous R-symmetry breaking, gaugino masses naturally at the scale of the Higgs mass parameters, and absence of CP violating phases.
Date: February 7, 2011
Creator: Schafer-Nameki, Sakura; Tamarit, Carlos & Torroba, Gonzalo
System: The UNT Digital Library
Measurement of the gamma gamma* --> eta and gamma gamma* --> eta' transition form factors (open access)

Measurement of the gamma gamma* --> eta and gamma gamma* --> eta' transition form factors

We study the reactions e{sup +}e{sup -} {yields} e{sup +}e{sup -} {eta}{sup (/)} in the single-tag mode and measure the {gamma}{gamma}* {yields} {eta}{sup (/)} transition form factors in the momentum transfer range from 4 to 40 GeV{sup 2}. The analysis is based on 469 fb{sup -1} of integrated luminosity collected at PEP-II with the BABAR detector at e{sup +}e{sup -} center-of-mass energies near 10.6 GeV.
Date: February 7, 2011
Creator: del Amo Sanchez et al, P.
System: The UNT Digital Library
Charm Spectroscopy from B Factories (open access)

Charm Spectroscopy from B Factories

A brief review of the excited D{sub s} and D mesons is presented. A precision measurement of the D{sub s1}(2536) mass and width parameters is reported by BABAR. Finally, a recent BABAR study of the D{pi} and D*{pi} final states shows first observations of the radial excitations of the D{sup 0}, D*{sup 0}, and D*{sup +}, as well as the L = 2 excited states of the D{sup 0} and D{sup +}, where L is the orbital angular momentum of the quarks.
Date: February 7, 2011
Creator: Benitez, J.
System: The UNT Digital Library
Small Column Ion Exchange Design and Safety Strategy (open access)

Small Column Ion Exchange Design and Safety Strategy

Small Column Ion Exchange (SCIX) is a transformational technology originally developed by the Department of Energy (DOE) Environmental Management (EM-30) office and is now being deployed at the Savannah River Site (SRS) to significantly increase overall salt processing capacity and accelerate the Liquid Waste System life-cycle. The process combines strontium and actinide removal using Monosodium Titanate (MST), Rotary Microfiltration, and cesium removal using Crystalline Silicotitanate (CST, specifically UOP IONSIV{reg_sign}IE-911 ion exchanger) to create a low level waste stream to be disposed in grout and a high level waste stream to be vitrified. The process also includes preparation of the streams for disposal, e.g., grinding of the loaded CST material. These waste processing components are technically mature and flowsheet integration studies are being performed including glass formulations studies, application specific thermal modeling, and mixing studies. The deployment program includes design and fabrication of the Rotary Microfilter (RMF) assembly, ion-exchange columns (IXCs), and grinder module, utilizing an integrated system safety design approach. The design concept is to install the process inside an existing waste tank, Tank 41H. The process consists of a feed pump with a set of four RMFs, two IXCs, a media grinder, three Submersible Mixer Pumps (SMPs), and all …
Date: February 7, 2011
Creator: Huff, T.; Rios-Armstrong, M.; Edwards, R. & Herman, D.
System: The UNT Digital Library
A 10,000 groove/mm multilayer coated grating for EUV spectroscopy (open access)

A 10,000 groove/mm multilayer coated grating for EUV spectroscopy

Ultra-high spectral resolution in the EUV and soft x-ray energy ranges requires the use of very high line density gratings with optimal design resulting in use of a Blazed Multilayer Grating (BMG) structure. Here we demonstrate the production of near-atomically perfect Si blazed substrates with an ultra-high groove density (10,000 l/mm) together with the measured and theoretical performance of an Al/Zr multilayer coating on the grating. A 1st order absolute efficiency of 13percent and 24.6percent was achieved at incidence angles of 11o and 36o respectively. Cross-sectional TEM shows the effect of smoothing caused by the surface mobility of deposited atoms and we correlate this effect with a reduction in peak diffraction efficiency. This work shows the high performance that can be achieved with BMGs based on small-period anisotropic etched Si substrates, but also the constraints imposed by the surface mobility of deposited species.
Date: February 7, 2011
Creator: Voronov, Dmytro; Anderson, Erik; Cambie, Rossana; Cabrini, Stefano; Dhuey, Scott; Goray, Leonid et al.
System: The UNT Digital Library
Design of Flexure-based Precision Transmission Mechanisms using Screw Theory (open access)

Design of Flexure-based Precision Transmission Mechanisms using Screw Theory

This paper enables the synthesis of flexure-based transmission mechanisms that possess multiple decoupled inputs and outputs of any type (e.g. rotations, translations, and/or screw motions), which are linked by designer-specified transmission ratios. A comprehensive library of geometric shapes is utilized from which every feasible concept that possesses the desired transmission characteristics may be rapidly conceptualized and compared before an optimal concept is selected. These geometric shapes represent the rigorous mathematics of screw theory and uniquely link a body's desired motions to the flexible constraints that enable those motions. This paper's impact is most significant to the design of nano-positioners, microscopy stages, optical mounts, and sensors. A flexure-based microscopy stage was designed, fabricated, and tested to demonstrate the utility of the theory.
Date: February 7, 2011
Creator: Hopkins, J B & Panas, R M
System: The UNT Digital Library
Photon Beamlines and Diagnostics at LCLS (open access)

Photon Beamlines and Diagnostics at LCLS

The Linac Coherent Light Source (LCLS) is the first hard-x-ray free electron laser in operation. The turn-on of LCLS was rapid and operation has been reliable. Performance has exceeded the design parameters in several areas. The photon energy output covers a range from 480 eV to over 9 keV; the pulse energy is typically 2-3 mJ, with a maximum of 4 mJ at 2 keV. Electron pulse lengths can be varied from 500 fs to shorter than 10 fs. A low-charge option at 20 pC is being explored, which delivers pulses shorter than 10 fs with a reduced pulse energy, typically around 0.2 mJ. On-demand, single-shot and multi-shot modes up to 60 Hz (planned is 120 Hz) can be made available. The photon diagnostics built for LCLS have been commissioned and provide measurements of various properties of the FEL beam, such as pulse energy, beam size and position, wavelength, and allows for intensity attenuation over the entire wavelength range. The two soft x-ray instruments, the Atomic Molecular and Optics (AMO) and Soft X-ray Material Science (SXR) stations, are fully operational and completed their second user run in mid September 2010. The third user run is scheduled from October to December …
Date: February 7, 2011
Creator: Moeller, S.; Arthur, J.; Brachmann, A.; Coffee, R.; Decker, F.-J.; Edstrom, S. et al.
System: The UNT Digital Library
MELTING OF GLASS BATCH - MODEL FOR MULTIPLE OVERLAPPING GAS-EVOLVING REACTIONS (open access)

MELTING OF GLASS BATCH - MODEL FOR MULTIPLE OVERLAPPING GAS-EVOLVING REACTIONS

In this study, we present a model for the kinetics of multiple overlapping reactions. Mathematical representation of the kinetics of gas-evolving reactions is crucial for the modeling of the feed-to-glass conversion in a waste-glass melter. The model simulates multiple gas-evolving reactions that occur during heating of a high-alumina high-level waste melter feed. To obtain satisfactory kinetic parameters, we employed Kissinger's method combined with least-squares analysis. The power-law kinetics with variable reaction order sufficed for obtaining excellent agreement with measured thermogravimetric analysis data.
Date: February 7, 2012
Creator: Kruger, A. A.; Pierce, D. A.; Pokorny, R. & Hrma, P. R.
System: The UNT Digital Library