Higher-Twist Contributions to Large Transverse Momentum Hadron Production in hadronic collisions (open access)

Higher-Twist Contributions to Large Transverse Momentum Hadron Production in hadronic collisions

The scaling behavior of large-p{sub {perpendicular}} hadron production in hadronic collisions is investigated. A significant deviation from the NLO QCD predictions is reported, especially at high values of x{sub {perpendicular}} = 2p{sub {perpendicular}}/{radical}s. In contrast, the prompt photon and jet production data prove in agreement with leading-twist expectations. These results are interpreted as coming from a non-negligible contribution of higher-twist processes, where the hadron is produced directly in the hard subprocess. Predictions for scaling exponents at RHIC are successfully compared to PHENIX preliminary measurements. We suggest to trigger on isolated large-p{sub {perpendicular}} hadron production to enhance higher-twist processes, and point that the use of isolated hadrons as a signal for new physics at colliders can be affected by the presence of direct hadron production processes.
Date: August 25, 2010
Creator: Arleo, Francois; /Annecy, LAPTH; Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; Hwang, Dae Sung; U., /Sejong et al.
Object Type: Article
System: The UNT Digital Library
Characterization of LER propagation in resists: Underlayer interfaces in ultra-thin resist films (open access)

Characterization of LER propagation in resists: Underlayer interfaces in ultra-thin resist films

None
Date: February 25, 2010
Creator: Georege, Simi; Naulleau, Patrick; Krishnamoorthy, Ahila; Wu, Zeyu; Kennedy, Joseph; Rutter, Edward et al.
Object Type: Article
System: The UNT Digital Library
Mechanical Design (open access)

Mechanical Design

The particle beam of the SXR (soft x-ray) beam line in the LCLS (Linac Coherent Light Source) has a high intensity in order to penetrate through samples at the atomic level. However, the intensity is so high that many experiments fail because of severe damage. To correct this issue, attenuators are put into the beam line to reduce this intensity to a level suitable for experimentation. Attenuation is defined as 'the gradual loss in intensity of any flux through a medium' by [1]. It is found that Beryllium and Boron Carbide can survive the intensity of the beam. At very thin films, both of these materials work very well as filters for reducing the beam intensity. Using a total of 12 filters, the first 9 being made of Beryllium and the rest made of Boron Carbide, the beam's energy range of photons can be attenuated between 800 eV and 9000 eV. The design of the filters allows attenuation for different beam intensities so that experiments can obtain different intensities from the beam if desired. The step of attenuation varies, but is relative to the thickness of the filter as a power function of 2. A relationship for this is f(n) …
Date: August 25, 2010
Creator: Shook, Richard & /SLAC, /Marquette U.
Object Type: Report
System: The UNT Digital Library
Summary of operations and performance of the Utica aquifer and North Lake Basin wetlands restoration project in December 2008-November 2009. (open access)

Summary of operations and performance of the Utica aquifer and North Lake Basin wetlands restoration project in December 2008-November 2009.

This document summarizes the performance of the groundwater restoration systems installed by the Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) at the former CCC/USDA grain storage facility in Utica, Nebraska, during the fifth year of system operation, from December 1, 2008, until November 30, 2009. Performance in earlier years was reported previously (Argonne 2005, 2006, 2008, 2009a). In the project at Utica, the CCC/USDA is cooperating with multiple state and federal agencies to remove carbon tetrachloride contamination from a shallow aquifer underlying the town and to provide supplemental treated groundwater for use in the restoration of a nearby wetlands area. Argonne National Laboratory has assisted the CCC/USDA by providing technical oversight for the aquifer restoration effort and facilities during this review period. This document presents overviews of the aquifer restoration facilities (Section 2) and system operations (Section 3), then describes groundwater production results (Section 4), groundwater treatment results (Section 5), and associated groundwater monitoring, system modifications, and costs during the review period (Section 6). Section 7 summarizes the present year of operation.
Date: May 25, 2010
Creator: LaFreniere, L. M. & Division, Environmental Science
Object Type: Report
System: The UNT Digital Library
Final Report for Colorado State University (open access)

Final Report for Colorado State University

The final report for the project entitled "Representation-Independent Compiler Technology for Domain-Specific Analysis with the OpenAnalysis Toolkit".
Date: June 25, 2010
Creator: Strout, Michelle Mills
Object Type: Report
System: The UNT Digital Library
Canada Geese at the Hanford Site – Trends in Reproductive Success, Migration Patterns, and Contaminant Concentrations (open access)

Canada Geese at the Hanford Site – Trends in Reproductive Success, Migration Patterns, and Contaminant Concentrations

Pacific Northwest National Laboratory (PNNL) has conducted several studies for the U.S. Department of Energy (DOE) to evaluate the status and condition of Canada geese on the Hanford Reach of the Columbia River. This report summarizes results of studies of Canada geese (Branta canadensis moffitti) at the Hanford Site dating back to the 1950s. Results include information on the nesting (reproductive) success of Canada geese using the Hanford Reach, review of the local and regional migration of this species using data from bird banding studies, and summary data describing monitoring and investigations of the accumulation of Hanford-derived and environmental contaminants by resident goose populations.
Date: May 25, 2010
Creator: Simmons, Mary Ann; Poston, Ted M.; Tiller, Brett L.; Stegen, Amanda; Hand, Kristine D. & Brandenberger, Jill M.
Object Type: Report
System: The UNT Digital Library
Optimal Model-Based Fault Estimation and Correction for Particle Accelerators and Industrial Plants Using Combined Support Vector Machines and First Principles Models (open access)

Optimal Model-Based Fault Estimation and Correction for Particle Accelerators and Industrial Plants Using Combined Support Vector Machines and First Principles Models

Timely estimation of deviations from optimal performance in complex systems and the ability to identify corrective measures in response to the estimated parameter deviations has been the subject of extensive research over the past four decades. The implications in terms of lost revenue from costly industrial processes, operation of large-scale public works projects and the volume of the published literature on this topic clearly indicates the significance of the problem. Applications range from manufacturing industries (integrated circuits, automotive, etc.), to large-scale chemical plants, pharmaceutical production, power distribution grids, and avionics. In this project we investigated a new framework for building parsimonious models that are suited for diagnosis and fault estimation of complex technical systems. We used Support Vector Machines (SVMs) to model potentially time-varying parameters of a First-Principles (FP) description of the process. The combined SVM & FP model was built (i.e. model parameters were trained) using constrained optimization techniques. We used the trained models to estimate faults affecting simulated beam lifetime. In the case where a large number of process inputs are required for model-based fault estimation, the proposed framework performs an optimal nonlinear principal component analysis of the large-scale input space, and creates a lower dimension feature space …
Date: August 25, 2010
Creator: Sayyar-Rodsari, Bijan; Schweiger, Carl & /SLAC /Pavilion Technologies, Inc., Austin, TX
Object Type: Report
System: The UNT Digital Library
Nonlinear Gyrokinetic Theory With Polarization Drift (open access)

Nonlinear Gyrokinetic Theory With Polarization Drift

A set of the electrostatic toroidal gyrokinetic Vlasov equation and the Poisson equation, which explicitly includes the polarization drift, is derived systematically by using Lie-transform method. The polarization drift is introduced in the gyrocenter equations of motion, and the corresponding polarization density is derived. Contrary to the wide-spread expectation, the inclusion of the polarization drift in the gyrocenter equations of motion does not affect the expression for the polarization density significantly. This is due to modification of the gyrocenter phase-space volume caused by the electrostatic potential [T. S. Hahm, Phys. Plasmas 3, 4658 (1996)] .
Date: March 25, 2010
Creator: Wang, L. & Hahm, T. S.
Object Type: Report
System: The UNT Digital Library
Experimental Measurements of the Secondary Electron Yield in the Experimental Measurement of the Secondary Electron Yield in the PEP-II Particle Accelerator Beam Line (open access)

Experimental Measurements of the Secondary Electron Yield in the Experimental Measurement of the Secondary Electron Yield in the PEP-II Particle Accelerator Beam Line

Beam instability caused by the electron cloud has been observed in positron and proton storage rings and it is expected to be a limiting factor in the performance of the positron Damping Ring (DR) of future Linear Colliders (LC) such as ILC and CLIC. To test a series of promising possible electron cloud mitigation techniques as surface coatings and grooves, in the Positron Low Energy Ring (LER) of the PEP-II accelerator, we have installed several test vacuum chambers including (i) a special chamber to monitor the variation of the secondary electron yield of technical surface materials and coatings under the effect of ion, electron and photon conditioning in situ in the beam line; (ii) chambers with grooves in a straight magnetic-free section; and (iii) coated chambers in a dedicated newly installed 4-magnet chicane to study mitigations in a magnetic field region. In this paper, we describe the ongoing R&D effort to mitigate the electron cloud effect for the LC damping ring, focusing on the first experimental area and on results of the reduction of the secondary electron yield due to in situ conditioning.
Date: August 25, 2010
Creator: Pivi, M. T. F.; Collet, G.; King, F.; Kirby, R. E.; Markiewicz, T.; Raubenheimer, T. O. et al.
Object Type: Article
System: The UNT Digital Library
Dynamic Characterization of Mock Explosive Material Using Reverse Taylor Impact Experiments (open access)

Dynamic Characterization of Mock Explosive Material Using Reverse Taylor Impact Experiments

The motivation for the current study is to evaluate the dynamic loading response of an inert mock explosive material used to replicate the physical and mechanical properties of LX-17-1 and PBX 9502 insensitive high explosives. The evaluation of dynamic material parameters is needed for predicting the deformation behavior including the onset of failure and intensity of fragmentation resulting from high velocity impact events. These parameters are necessary for developing and validating physically based material constitutive models that will characterize the safety and performance of energetic materials. The preliminary study uses a reverse Taylor impact configuration that was designed to measure the dynamic behavior of the explosive mock up to and including associated fragmentation. A stationary rod-shaped specimen was impacted using a compressed-gas gun by accelerating a rigid steel anvil attached to a sabot. The impact test employed high-speed imaging and velocity interferometry diagnostics for capturing the transient deformation of the sample at discrete times. Once established as a viable experimental technique with mock explosives, future studies will examine the dynamic response of insensitive high explosives and propellants.
Date: March 25, 2010
Creator: Ferranti, L; Gagliardi, F J; Cunningham, B J & Vandersall, K S
Object Type: Article
System: The UNT Digital Library
2010 Soil Characterization Report for the Area 11 Explosive Ordnance Disposal Unit, Nevada Test Site (open access)

2010 Soil Characterization Report for the Area 11 Explosive Ordnance Disposal Unit, Nevada Test Site

This soil characterization report summarizes sampling activities and analytical results, provides copies of laboratory data reports, and meets the requirements of Section IV.G.2 of the Permit (NEV HW0021, November 2005) and Sections P.3.d.7.b and P.3.n of the Permit Application (DOE/NV--1053-VOL 4, May 2005).
Date: February 25, 2010
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
Search for Muon Neutrino Disappearance in a Short-Baseline Accelerator Neutrino Beam (open access)

Search for Muon Neutrino Disappearance in a Short-Baseline Accelerator Neutrino Beam

We report a search for muon neutrino disappearance in the {Delta}m{sup 2} region of 0.5--40 eV{sup 2} using data from both Sci-BooNE and MiniBooNE experiments. SciBooNE data provides a constraint on the neutrino flux, so that the sensitivity to {nu}{sub {mu}} disappearance with both detectors is better than with just MiniBooNE alone. The preliminary sensitivity for a joint {nu}{sub {mu}} disappearance search is presented.
Date: April 25, 2010
Creator: Nakajima, Y. & U., /Kyoto
Object Type: Article
System: The UNT Digital Library
Towards an Understanding of the Role of Aragonite in the Mechanical Properties of Nacre (open access)

Towards an Understanding of the Role of Aragonite in the Mechanical Properties of Nacre

Nacre, also known as mother-of-pearl, is a biocomposite material that exhibits higher strength and fracture toughness than its component materials. It derives its strength from the brick-and-mortar layering of aragonite (CaCO{sub 3}) platelets and organic binder. It is believed that the protein binder helps redistribute the stress throughout all tablets for optimal mechanical performance. In this study, we attempt to measure the mechanical properties of aragonite within nacre and compare them to bulk aragonite and bulk nacre and understand the redistribution of stresses. Here we show that x-ray diffraction techniques are useful for isolating and measuring strain of crystallites within a composite material. Our results show that the apparent stiffness of aragonite varies with crystallographic directions and is higher than the stiffness of bulk nacre in all cases, meaning that aragonite tablets are exposed to less than the average bulk stress. The average force applied to the bulk sample is partitioned between the aragonite and the binder, so that the protein layer bears as much as 27.2% of the total applied force. Different crystallographic directions exhibit behaviors different than bulk aragonite or bulk nacre. These are related to texture of aragonite platelets (i.e. preferred orientations within nacre). By examining nacre, …
Date: August 25, 2010
Creator: unknown
Object Type: Report
System: The UNT Digital Library
MBE Growth of Graded Structures for Polarized Electron Emitters (open access)

MBE Growth of Graded Structures for Polarized Electron Emitters

SVT Associates, in collaboration with SLAC, have investigated two novel photocathode design concepts in an effort to increase polarization and quantum efficiency. AlGaAsSb/GaAs superlattice photocathodes were fabricated to explore the effect of antimony on device operation. In the second approach, an internal electrical field was created within the superlattice active layer by varying the aluminum composition in AlGaAs/GaAs. A 25% increase in quantum efficiency as a result of the gradient was observed.
Date: August 25, 2010
Creator: unknown
Object Type: Report
System: The UNT Digital Library
A Radiometric All-Sky Infrared Camera (RASICAM) for DES/CTIO (open access)

A Radiometric All-Sky Infrared Camera (RASICAM) for DES/CTIO

A novel radiometric all-sky infrared camera [RASICAM] has been constructed to allow automated real-time quantitative assessment of night sky conditions for the Dark Energy Camera [DECam] located on the Blanco Telescope at the Cerro Tololo Inter-American Observatory in Chile. The camera is optimized to detect the position, motion and optical depth of thin, high (8-10km) cirrus clouds and contrails by measuring their apparent temperature above the night sky background. The camera system utilizes a novel wide-field equiresolution catadioptic mirror system that provides sky coverage of 2{pi} azimuth and 14-90{sup o} from zenith. Several new technological and design innovations allow the RASICAM system to provide unprecedented cloud detection and IR-based photometricity quantification. The design of the RASICAM system is presented.
Date: August 25, 2010
Creator: Lewis, Peter M.; Rogers, Howard & Schindler, Rafe H.
Object Type: Article
System: The UNT Digital Library
Higgs Mass Constraints on a Fourth Family: Upper and Lower Limits on CKM Mixing (open access)

Higgs Mass Constraints on a Fourth Family: Upper and Lower Limits on CKM Mixing

Theoretical and experimental limits on the Higgs boson mass restrict CKM mixing of a possible fourth family beyond the constraints previously obtained from precision electroweak data alone. Existing experimental and theoretical bounds on m{sub H} already significantly restrict the allowed parameter space. Zero CKM mixing is excluded and mixing of order {theta}{sub Cabbibo} is allowed. Upper and lower limits on 3-4 CKM mixing are exhibited as a function of m{sub H}. We use the default inputs of the Electroweak Working Group and also explore the sensitivity of both the three and four family fits to alternative inputs.
Date: June 25, 2010
Creator: Chanowitz, Michael S.
Object Type: Article
System: The UNT Digital Library
X-Ray Tomographic Reconstruction (open access)

X-Ray Tomographic Reconstruction

Tomographic scans have revolutionized imaging techniques used in medical and biological research by resolving individual sample slices instead of several superimposed images that are obtained from regular x-ray scans. X-Ray fluorescence computed tomography, a more specific tomography technique, bombards the sample with synchrotron x-rays and detects the fluorescent photons emitted from the sample. However, since x-rays are attenuated as they pass through the sample, tomographic scans often produce images with erroneous low densities in areas where the x-rays have already passed through most of the sample. To correct for this and correctly reconstruct the data in order to obtain the most accurate images, a program employing iterative methods based on the inverse Radon transform was written. Applying this reconstruction method to a tomographic image recovered some of the lost densities, providing a more accurate image from which element concentrations and internal structure can be determined.
Date: August 25, 2010
Creator: Schmittberger, Bonnie
Object Type: Report
System: The UNT Digital Library
Status of Neutrino Physics Experiments (open access)

Status of Neutrino Physics Experiments

Relevant results from neutrino physics experiments since FPCP2009 with an emphasis on oscillations and the ability to measure or limit the mixing angle {theta}{sub 13}.
Date: May 25, 2010
Creator: Jaffe, D.
Object Type: Article
System: The UNT Digital Library
Noise Amplification in Echo-Enabled Harmonic Generation (EEHG) (open access)

Noise Amplification in Echo-Enabled Harmonic Generation (EEHG)

Two essential elements of a seeded FEL based on the echo-enabled harmonic generation (EEHG) are the undulator-modulators, in which a laser beam modulates the beam energy. We study how the interaction of electrons in these undulators changes the noise properties of the beam. This paper is based on the method of noise analysis developed in Ref. [1] and extends it for the case of EEHG.
Date: August 25, 2010
Creator: Stupakov, Gennady
Object Type: Article
System: The UNT Digital Library
Gauge/Gravity Duality and Hadron Physics in the Light-Front (open access)

Gauge/Gravity Duality and Hadron Physics in the Light-Front

We discuss some remarkable features of the light-front holographic mapping of classical gravity in anti-de Sitter space modified by a confining dilaton background. In particular, we show that a positive-sign dilaton solution exp(+k{sup 2}z{sup 2}) has better chances to describe the correct hadronic phenomenology than the negative solution exp (-k{sup 2}z{sup 2}) extensively studied in the literature. We also show that the use of twist-scaling dimensions, instead of canonical dimensions, is required to give a good description of the spectrum and form factors of hadrons. Another key element is the explicit connection of AdS modes of total angular momentum J with the internal structure of hadrons and the proper identification of the orbital angular momentum of the constituents.
Date: August 25, 2010
Creator: de Teramond, Guy F.; U., /Costa Rica; Brodsky, Stanley J. & /SLAC /Southern Denmark U., CP3-Origins
Object Type: Article
System: The UNT Digital Library
Synthesis of Samarium Cobalt Nanoblades (open access)

Synthesis of Samarium Cobalt Nanoblades

As new portable particle acceleration technologies become feasible the need for small high performance permanent magnets becomes critical. With particle accelerating cavities of a few microns, the photonic crystal fiber (PCF) candidate demands magnets of comparable size. To address this need, samarium cobalt (SmCo) nanoblades were attempted to be synthesized using the polyol process. Since it is preferable to have blades of 1-2 {micro}m in length, key parameters affecting size and morphology including method of stirring, reaction temperature, reaction time and addition of hydroxide were examined. Nanoparticles consisting of 70-200 nm spherical clusters with a 3-5 nm polyvinylpyrrolidone (PVP) coating were synthesized at 285 C and found to be ferromagnetic. Nanoblades of 25nm in length were observed at the surface of the nanoclusters and appeared to suggest agglomeration was occurring even with PVP employed. Morphology and size were characterized using a transmission electron microscope (TEM). Powder X-Ray Diffraction (XRD) analysis was conducted to determine composition but no supportive evidence for any particular SmCo phase has yet been observed.
Date: August 25, 2010
Creator: Steele, Darren M.
Object Type: Report
System: The UNT Digital Library
Thermometric- and Acoustic-Based Beam Power Monitor for Ultra-Bright X-Rays (open access)

Thermometric- and Acoustic-Based Beam Power Monitor for Ultra-Bright X-Rays

A design for an average beam power monitor for ultra-bright X-ray sources is proposed that makes simultaneous use of calorimetry and radiation acoustics. Radiation incident on a solid target will induce heating and ultrasonic vibrations, both of which may be measured to give a fairly precise value of the beam power. The monitor is intended for measuring ultra-bright Free-Electron Laser (FEL) X-ray beams, for which traditional monitoring technologies such as photo-diodes or scintillators are unsuitable. The monitor consists of a Boron Carbide (B{sub 4}C) target designed to absorb most of the incident beam's energy. Resistance temperature detectors (RTD) and piezoelectric actuators are mounted on the outward faces of the target to measure the temperature changes and ultrasonic vibrations induced by the incident beam. The design was tested using an optical pulsed beam (780 nm, 120 and 360 Hz) from a Ti:sapphire oscillator at several energies between 0.8 and 2.6 mJ. The RTDs measured an increase in temperature of about 10 K over a period of several minutes. The piezoelectric sensors recorded ringing acoustic oscillations at 580 {+-} 40 kHz. Most importantly, the amplitude of the acoustic signals was observed to scale linearly with beam power up to 2 mJ of …
Date: August 25, 2010
Creator: Bentsen, Gregory & /SLAC, /Rochester U.
Object Type: Report
System: The UNT Digital Library
Lattice Development for Pep-X High Brightness Light Source (open access)

Lattice Development for Pep-X High Brightness Light Source

Design of PEP-X high brightness light source machine is under development at SLAC. The PEP-X is a proposed replacement for the PEP-II in the existing 2.2 km tunnel. Two of the PEP-X six arcs contain DBA type lattice providing 30 dispersion free straights suitable for 3.5 m long undulators. The lattice contains TME cells in the other four arcs and 89.3 m wiggler in a long straight section yielding a horizontal emittance of {approx}0.1 nm-rad at 4.5 GeV. The recent lattice modifications are aimed at increasing the predicted brightness and improving beam dynamic properties. The standard DBA cells are modified into supercells for providing low-{beta} undulator straights. The DBA and TME cell phase advance is better optimized. Harmonic sextupoles are added to minimize the sextupole driven resonance effects and amplitude dependent tune shift. Finally, the injection scheme is changed from vertical to horizontal plane in order to avoid large vertical amplitudes of injected beam within small vertical aperture of undulators.
Date: August 25, 2010
Creator: Nosochkov, Yuri; Cai, Yunhai & Wang, Min-Huey
Object Type: Article
System: The UNT Digital Library
COMPARISON OF SIMULATION CODES FOR MICROWAVE INSTABILITY IN BUNCHED BEAMS (open access)

COMPARISON OF SIMULATION CODES FOR MICROWAVE INSTABILITY IN BUNCHED BEAMS

In accelerator design, there is often a need to evaluate the threshold to the (longitudinal) microwave instability for a bunched beam in an electron storage ring. Several computational tools are available that allow them, once given the wakefield representing a ring, to numerically find the threshold current and to simulate the development of the instability. In this work, they present results of coputer simulations using two codes recently developed at the SLAC National Accelerator Laboratory: a Vlasov-Fokker-Planck (VFP) solver based on an algorithm by Warnock and Ellison, and a program that find the threshold from the linearized Vlasov equation. They apply the programs to find the instability threshold for three models of ring impedances: that of a Q = 1 resonator, of shielded coherent synchrotron radiation (CSR), and of a resistive wall. The first example is wel-bheaved, but the other two are singular wakes that need special care. Note that similar numerical studies of the threshold of a Q = 1 resonantor wake have been performed by Oide and Yokova, and others. They compare the results of the two programs and discuss their respective capabilities and limitations. In this report they assume the slippage factor {eta} is always positive. They …
Date: August 25, 2010
Creator: Bane, K.L.F.; Cai, Y. & Stupakov, G.
Object Type: Article
System: The UNT Digital Library