Edge Turbulence Velocity Changes with Lithium Coating on NSTX (open access)

Edge Turbulence Velocity Changes with Lithium Coating on NSTX

Lithium coating improves energy confinement and eliminates edge localized modes in NSTX, but the mechanism of this improvement is not yet well understood. We used the gas-puff-imaging (GPI) diagnostic on NSTX to measure the changes in edge turbulence which occurred during a scan with variable lithium wall coating, in order to help understand the reason for the confinement improvement with lithium. There was a small increase in the edge turbulence poloidal velocity and a decrease in the poloidal velocity fluctuation level with increased lithium. The possible effect of varying edge neutral density on turbulence damping was evaluated for these cases in NSTX. __________________________________________________
Date: August 10, 2012
Creator: A. Cao, S.J. Zweben, D.P. Stotler, M. Bell, A. Diallo, S.M. Kaye and B. LeBlanc
Object Type: Report
System: The UNT Digital Library
Potential for luminosity improvement for low-energy RHIC operation with long bunches (open access)

Potential for luminosity improvement for low-energy RHIC operation with long bunches

Electron cooling was proposed to increase luminosity of the RHIC collider for heavy ion beams at low energies. Luminosity decreases as the square of bunch intensity due to the beam loss from the RF bucket as a result of the longitudinal intra beam scattering (IBS), as well as due to the transverse emittance growth because of the transverse IBS. Both transverse and longitudinal IBS can be counteracted with electron cooling. This would allow one to keep the initial peak luminosity close to constant throughout the store essentially without the beam loss. In addition, the phase-space density of the hadron beams can be further increased by providing stronger electron cooling. Unfortunately, the defining limitation for low energies in RHIC is expected to be the space charge. Here we explore an idea of additional improvement in luminosity, on top of the one coming from just IBS compensation and longer stores, which may be expected if one can operate with longer bunches at the space-charge limit in a collider. This approach together with electron cooling may result in about 10-fold improvement in total luminosity for low-energy RHIC program.
Date: February 10, 2012
Creator: A., Fedotov; Blaskiewicz&#44 & M.
Object Type: Report
System: The UNT Digital Library
LITERATURE REVIEW ON IMPACT OF GLYCOLATE ON THE 2H EVAPORATOR AND THE EFFLUENT TREATMENT FACILITY (open access)

LITERATURE REVIEW ON IMPACT OF GLYCOLATE ON THE 2H EVAPORATOR AND THE EFFLUENT TREATMENT FACILITY

Glycolic acid (GA) is being studied as an alternate reductant in the Defense Waste Processing Facility (DWPF) feed preparation process. It will either be a total or partial replacement for the formic acid that is currently used. A literature review has been conducted on the impact of glycolate on two post-DWPF downstream systems - the 2H Evaporator system and the Effluent Treatment Facility (ETF). The DWPF recycle stream serves as a portion of the feed to the 2H Evaporator. Glycolate enters the evaporator system from the glycolate in the recycle stream. The overhead (i.e., condensed phase) from the 2H Evaporator serves as a portion of the feed to the ETF. The literature search revealed that virtually no impact is anticipated for the 2H Evaporator. Glycolate may help reduce scale formation in the evaporator due to its high complexing ability. The drawback of the solubilizing ability is the potential impact on the criticality analysis of the 2H Evaporator system. It is recommended that at least a theoretical evaluation to confirm the finding that no self-propagating violent reactions with nitrate/nitrites will occur should be performed. Similarly, identification of sources of ignition relevant to glycolate and/or update of the composite flammability analysis to …
Date: May 10, 2012
Creator: Adu-Wusu, K.
Object Type: Report
System: The UNT Digital Library
Measuring Sparticles with the Matrix Element (open access)

Measuring Sparticles with the Matrix Element

We apply the Matrix Element Method (MEM) to mass determination of squark pair production with direct decay to quarks and LSP at the LHC, showing that simultaneous mass determination of squarks and LSP is possible. We furthermore propose methods for inclusion of QCD radiation effects in the MEM. The goal of the LHC at CERN, scheduled to start this year, is to discover new physics through deviations from the Standard Model (SM) predictions. After discovery of deviations from the SM, the next step will be classification of the new physics. An important first goal in this process will be establishing a mass spectrum of the new particles. One of the most challenging scenarios is pair-production of new particles which decay to invisible massive particles, giving missing energy signals. Many methods have been proposed for mass determination in such scenarios (for a recent list of references, see e.g. [1]). In this proceeding, we report the first steps in applying the Matrix Element Method (MEM) in the context of supersymmetric scenarios giving missing energy signals. After a quick review of the MEM, we will focus on squark pair production, a process where other mass determination techniques have difficulties to simultaneously determine the …
Date: April 10, 2012
Creator: Alwall, Johan; /SLAC /Taiwan, Natl. Taiwan U.; Freitas, Ayres; U., /Pittsburgh; Mattelaer, Olivier & /INFN, Rome3 /Rome III U. /Louvain U.
Object Type: Article
System: The UNT Digital Library
Stauts of the Laser Inertial Fusion Energy (LIFE) Hohlraum Point Design (open access)

Stauts of the Laser Inertial Fusion Energy (LIFE) Hohlraum Point Design

Progress on the hohlraum point design for the LIFE engine is described. New features in the original design [Amendt et al., Fus. Sci. Technol. 60, 49 (2011)] are incorporated that address the imperatives of low target cost, high manufacturing throughput, efficient and prompt material recycling, an ability for near-term testing of key target design uncertainties on the National Ignition Facility, and robustness to target chamber environment and injection insults. To this end, the novel use of Pb hohlraums and aerogel-supported liquid DT fuel loading within a high-density-carbon (HDC) ablator is implemented in the hohlraum point design.
Date: April 10, 2012
Creator: Amendt, P.; Dunne, M.; Ho, D.; Lasinski, B.; Meeker, D. & Ross, J. S.
Object Type: Article
System: The UNT Digital Library
The SM and NLO Multileg Working Group: Summary Report (open access)

The SM and NLO Multileg Working Group: Summary Report

After years of waiting, and after six Les Houches workshops, the era of LHC running is finally upon us, albeit at a lower initial center-of-mass energy than originally planned. Thus, there has been a great sense of anticipation from both the experimental and theoretical communities. The last two years, in particular, have seen great productivity in the area of multi-parton calculations at leading order (LO), next-to-leading order (NLO) and next-to-next-to-leading order (NNLO), and this productivity is reflected in the proceedings of the NLM group. Both religions, Feynmanians and Unitarians, as well as agnostic experimenters, were well-represented in both the discussions at Les Houches, and in the contributions to the write-up. Next-to-leading order (NLO) is the first order at which the normalization, and in some cases the shape, of perturbative cross sections can be considered reliable. This can be especially true when probing extreme kinematic regions, as for example with boosted Higgs searches considered in several of the contributions to this writeup. A full understanding for both standard model and beyond the standard model physics at the LHC requires the development of fast, reliable programs for the calculation of multi-parton final states at NLO. There have been many advances in the …
Date: April 10, 2012
Creator: Andersen, J. R.; Archibald, J.; Badger, S.; Ball, R. D.; Bevilacqua, G.; Bierenbaum, I. et al.
Object Type: Article
System: The UNT Digital Library
Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab (open access)

Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab

A high energy beam absorber has been built for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In the facility's initial configuration, an electron beam will be accelerated through 3 TTF-type or ILC-type SRF cryomodules to an energy of 750MeV. The electron beam will be directed to one of multiple downstream experimental and diagnostic beam lines and then deposited in one of two beam absorbers. The facility is designed to accommodate up to 6 cryomodules, which would produce a 75kW beam at 1.5GeV; this is the driving design condition for the beam absorbers. The beam absorbers consist of water-cooled graphite, aluminum and copper layers contained in a helium-filled enclosure. This paper describes the mechanical implementation of the beam absorbers, with a focus on thermal design and analysis. The potential for radiation-induced degradation of the graphite is discussed.
Date: May 10, 2012
Creator: Baffes, C.; Church, M.; Leibfritz, J.; Oplt, S. & Rakhno, I.
Object Type: Article
System: The UNT Digital Library
Mach-Zehnder Modulator Performance Using the Comet Laser Facility and Implications for Use on NIF (open access)

Mach-Zehnder Modulator Performance Using the Comet Laser Facility and Implications for Use on NIF

None
Date: July 10, 2012
Creator: Beeman, B.; MacPhee, A. G.; Kimbrough, J. R.; Lacaille, G. A.; Barrios, M. A.; Emig, J. et al.
Object Type: Article
System: The UNT Digital Library
On the Lack of Evolution in Galaxy Star Formation Efficiency (open access)

On the Lack of Evolution in Galaxy Star Formation Efficiency

None
Date: December 10, 2012
Creator: Behroozi, Peter S.; Wechsler, Risa H.; /KIPAC, Menlo Park /SLAC; Conroy, Charlie & /UC, Santa Cruz, Astron. Astrophys.
Object Type: Article
System: The UNT Digital Library
Clic Cdr - Physics and Detectors: Clic Conceptual Design Report. (open access)

Clic Cdr - Physics and Detectors: Clic Conceptual Design Report.

This report forms part of the Conceptual Design Report (CDR) of the Compact LInear Collider (CLIC). The CLIC accelerator complex is described in a separate CDR volume. A third document, to appear later, will assess strategic scenarios for building and operating CLIC in successive center-of-mass energy stages. It is anticipated that CLIC will commence with operation at a few hundred GeV, giving access to precision standard-model physics like Higgs and top-quark physics. Then, depending on the physics landscape, CLIC operation would be staged in a few steps ultimately reaching the maximum 3 TeV center-of-mass energy. Such a scenario would maximize the physics potential of CLIC providing new physics discovery potential over a wide range of energies and the ability to make precision measurements of possible new states previously discovered at the Large Hadron Collider (LHC). The main purpose of this document is to address the physics potential of a future multi-TeV e{sup +}e{sup -} collider based on CLIC technology and to describe the essential features of a detector that are required to deliver the full physics potential of this machine. The experimental conditions at CLIC are significantly more challenging than those at previous electron-positron colliders due to the much higher …
Date: February 10, 2012
Creator: Berger, E.; Demarteau, M.; Repond, J.; Xia, L. & Weerts, H.
Object Type: Report
System: The UNT Digital Library
DEVELOPMENT OF THE HS99 AIR TRANSPORT TYPE A FISSILE PACKAGE (open access)

DEVELOPMENT OF THE HS99 AIR TRANSPORT TYPE A FISSILE PACKAGE

An air-transport Type A Fissile radioactive shipping package for the transport of special form uranium sources has been developed by the Savannah River National Laboratory (SRNL) for the Department of Homeland Security. The Package model number is HS99 for Homeland Security Model 99. This paper presents the major design features of the HS99 and highlights engineered materials necessary for meeting the design requirements for this light-weight Type AF packaging. A discussion is provided demonstrating how the HS99 complies with the regulatory safety requirements of the Nuclear Regulatory Commission. The paper summarizes the results of structural testing to specified in 10 CFR 71 for Normal Conditions of Transport and Hypothetical Accident Conditions events. Planned and proposed future missions for this packaging are also addressed.
Date: July 10, 2012
Creator: Blanton, P. & Eberl, K.
Object Type: Article
System: The UNT Digital Library
Multiplexed gas spectroscopy using tunable VCSELs (open access)

Multiplexed gas spectroscopy using tunable VCSELs

Detection and identification of gas species using tunable laser diode laser absorption spectroscopy has been performed using vertical cavity surface emitting lasers (VCSEL). Two detection methods are compared: direct absorbance and wavelength modulation spectroscopy (WMS). In the first, the output of a DC-based laser is directly monitored to detect for any quench at the targeted specie wavelength. In the latter, the emission wavelength of the laser is modulated by applying a sinusoidal component on the drive current of frequency {omega}, and measuring the harmonics component (2{omega}) of the photo-detected current. This method shows a better sensitivity measured as signal to noise ratio, and is less susceptible to interference effects such as scattering or fouling. Gas detection was initially performed at room temperature and atmospheric conditions using VCSELs of emission wavelength 763 nm for oxygen and 1392 nm for water, scanning over a range of approximately 10 nm, sufficient to cover 5-10 gas specific absorption lines that enable identification and quantization of gas composition. The amplitude and frequency modulation parameters were optimized for each detected gas species, by performing two dimensional sweeps for both tuning current and either amplitude or frequency, respectively. We found that the highest detected signal is observed …
Date: April 10, 2012
Creator: Bond, T; Bond, S; McCarrick, J; Zumstein, J; Chang, A; Moran, B et al.
Object Type: Article
System: The UNT Digital Library
The role of members of viral quasispecies in adaptation to new host environments (open access)

The role of members of viral quasispecies in adaptation to new host environments

None
Date: February 10, 2012
Creator: Borucki, M.; Allen, J. E.; Chen-Harris, H.; Mabery, S.; Vanier, G.; Torres, C. et al.
Object Type: Article
System: The UNT Digital Library
NEAMS Update. Quarterly Report for April - June 2012 (open access)

NEAMS Update. Quarterly Report for April - June 2012

None
Date: August 10, 2012
Creator: Bradley, K. S.; Hayes, S.; Pointer, D.; Summers, R.; Sadasivan, P.; Sun, X. et al.
Object Type: Report
System: The UNT Digital Library
NEAMS update quarterly report for January - March 2012. (open access)

NEAMS update quarterly report for January - March 2012.

Quarterly highlights are: (1) The integration of Denovo and AMP was demonstrated in an AMP simulation of the thermo-mechanics of a complete fuel assembly; (2) Bison was enhanced with a mechanistic fuel cracking model; (3) Mechanistic algorithms were incorporated into various lower-length-scale models to represent fission gases and dislocations in UO2 fuels; (4) Marmot was improved to allow faster testing of mesoscale models using larger problem domains; (5) Component models of reactor piping were developed for use in Relap-7; (6) The mesh generator of Proteus was updated to accept a mesh specification from Moose and equations were formulated for the intermediate-fidelity Proteus-2D1D module; (7) A new pressure solver was implemented in Nek5000 and demonstrated to work 2.5 times faster than the previous solver; (8) Work continued on volume-holdup models for two fuel reprocessing operations: voloxidation and dissolution; (9) Progress was made on a pyroprocessing model and the characterization of pyroprocessing emission signatures; (10) A new 1D groundwater waste transport code was delivered to the used fuel disposition (UFD) campaign; (11) Efforts on waste form modeling included empirical simulation of sodium-borosilicate glass compositions; (12) The Waste team developed three prototypes for modeling hydride reorientation in fuel cladding during very long-term fuel …
Date: May 10, 2012
Creator: Bradley, K. S.; Hayes, S.; Pointer, D.; Summers, R.; Sadasivan, P.; Sun, X. et al.
Object Type: Report
System: The UNT Digital Library
Derivation of site-specific relationships between hydraulic parameters and p-wave velocities based on hydraulic and seismic tomography (open access)

Derivation of site-specific relationships between hydraulic parameters and p-wave velocities based on hydraulic and seismic tomography

In this study, hydraulic and seismic tomographic measurements were used to derive a site-specific relationship between the geophysical parameter p-wave velocity and the hydraulic parameters, diffusivity and specific storage. Our field study includes diffusivity tomograms derived from hydraulic travel time tomography, specific storage tomograms, derived from hydraulic attenuation tomography, and p-wave velocity tomograms, derived from seismic tomography. The tomographic inversion was performed in all three cases with the SIRT (Simultaneous Iterative Reconstruction Technique) algorithm, using a ray tracing technique with curved trajectories. The experimental set-up was designed such that the p-wave velocity tomogram overlaps the hydraulic tomograms by half. The experiments were performed at a wellcharacterized sand and gravel aquifer, located in the Leine River valley near Göttingen, Germany. Access to the shallow subsurface was provided by direct-push technology. The high spatial resolution of hydraulic and seismic tomography was exploited to derive representative site-specific relationships between the hydraulic and geophysical parameters, based on the area where geophysical and hydraulic tests were performed. The transformation of the p-wave velocities into hydraulic properties was undertaken using a k-means cluster analysis. Results demonstrate that the combination of hydraulic and geophysical tomographic data is a promising approach to improve hydrogeophysical site characterization.
Date: January 10, 2012
Creator: Brauchler, R.; Doetsch, J.; Dietrich, P. & Sauter, M.
Object Type: Article
System: The UNT Digital Library
Compiled MPI: Cost-Effective Exascale Applications Development (open access)

Compiled MPI: Cost-Effective Exascale Applications Development

The complexity of petascale and exascale machines makes it increasingly difficult to develop applications that can take advantage of them. Future systems are expected to feature billion-way parallelism, complex heterogeneous compute nodes and poor availability of memory (Peter Kogge, 2008). This new challenge for application development is motivating a significant amount of research and development on new programming models and runtime systems designed to simplify large-scale application development. Unfortunately, DoE has significant multi-decadal investment in a large family of mission-critical scientific applications. Scaling these applications to exascale machines will require a significant investment that will dwarf the costs of hardware procurement. A key reason for the difficulty in transitioning today's applications to exascale hardware is their reliance on explicit programming techniques, such as the Message Passing Interface (MPI) programming model to enable parallelism. MPI provides a portable and high performance message-passing system that enables scalable performance on a wide variety of platforms. However, it also forces developers to lock the details of parallelization together with application logic, making it very difficult to adapt the application to significant changes in the underlying system. Further, MPI's explicit interface makes it difficult to separate the application's synchronization and communication structure, reducing the amount …
Date: April 10, 2012
Creator: Bronevetsky, G.; Quinlan, D.; Lumsdaine, A. & Hoefler, T.
Object Type: Report
System: The UNT Digital Library
Measurements of the Electron Cloud Density in the PEP-II Low Energy Ring (open access)

Measurements of the Electron Cloud Density in the PEP-II Low Energy Ring

Clouds of low energy electrons in the vacuum beam pipes of accelerators of positively charged particle beams present a serious limitation for operation of these machines at high currents. Because of the size of these accelerators, it is difficult to probe the low energy electron clouds over substantial lengths of the beam pipe. We have developed a novel technique to directly measure the electron cloud density via the phase shift induced in a TE wave that is independently excited and transmitted over a section of the accelerator. We infer the absolute phase shift with relatively high accuracy from the phase modulation of the transmission due to the modulation of the electron cloud density from a gap in the positively charged beam. We have used this technique for the first time to measure the average electron cloud density over a 50 m straight section in the positron ring of the PEP-II collider at the Stanford Linear Accelerator Center. We have also measured the variation of the density by using low field solenoid magnets to control the electrons.
Date: April 10, 2012
Creator: Byrd, J.; De Santis, S.; Sonnad, K.; Caspers, F.; Kroyer, T.; Krasnykh, A. et al.
Object Type: Article
System: The UNT Digital Library
Final Technical Report for DUSEL Research and Development on Sub-Kelvin Germanium Detectors for Ton Scale Dark Matter Search (open access)

Final Technical Report for DUSEL Research and Development on Sub-Kelvin Germanium Detectors for Ton Scale Dark Matter Search

We have supported one graduate student and a small percentage of fabrication staff on $135k per year for three years plus one no cost extension year on this DUSEL R&D grant.  There were three themes within our research program: (1) how to improve the radial sensitivity for single sided phonon readout with four equal area sensors of which three form a central circle and fourth a surrounding ring; (2) how to instrument double sided phonon readouts which will give us better surface event rejection and increased fiducial volume for future CDMS style detectors; and (3) can we manufacture much larger Ge detectors using six inch diameter material which is not suitable for standard gamma ray spectroscopy.
Date: September 10, 2012
Creator: Cabrera, Prof. Blas
Object Type: Report
System: The UNT Digital Library
Theory of Microwave Instability and Coherent Synchrotron Radiation in Electron Storage Rings (open access)

Theory of Microwave Instability and Coherent Synchrotron Radiation in Electron Storage Rings

None
Date: December 10, 2012
Creator: Cai, Y
Object Type: Article
System: The UNT Digital Library
Biofuels from Bacteria, Electricity, and CO2 (open access)

Biofuels from Bacteria, Electricity, and CO2

Advanced Research Projects Agency-Energy project sheet summarizing general information about the Electrofuels program including critical needs, innovation and advantages, impacts, and contact information. This sheet discusses combining ammonia and bacteria to produce liquid fuel as part of the "Biofuels from CO2 Using Ammonia or Iron-Oxidizing Bacteria in Reverse Microbial Fuel Cells" project.
Date: May 10, 2012
Creator: Columbia University
Object Type: Text
System: The UNT Digital Library
A New Biology for the 21st Century; Ensuring the United States Leads the Coming Biology Revolution (open access)

A New Biology for the 21st Century; Ensuring the United States Leads the Coming Biology Revolution

In July, 2008, the National Institutes of Health (NIH), National Science Foundation (NSF), and Department of Energy (DOE) asked the National Research Council’s Board on Life Sciences to convene a committee to examine the current state of biological research in the United States and recommend how best to capitalize on recent technological and scientific advances that have allowed biologists to integrate biological research findings, collect and interpret vastly increased amounts of data, and predict the behavior of complex biological systems. From September 2008 through July of 2009, a committee of 16 experts from the fields of biology, engineering and computational science undertook to delineate those scientific and technological advances and come to a consensus on how the U.S. might best capitalize on them. This report, authored by the Committee on a New Biology for the 21st Century, describes the committee’s work and conclusions.
Date: May 10, 2012
Creator: Committee on a New Biology for the 21st Century
Object Type: Report
System: The UNT Digital Library
Proceedings of RIKEN BNL Research Center Workshop: P- and CP-odd Effects in Hot and Dense Matter (2012) (open access)

Proceedings of RIKEN BNL Research Center Workshop: P- and CP-odd Effects in Hot and Dense Matter (2012)

N/A
Date: August 10, 2012
Creator: D., Kharzeev; Liao, J.; Shuryak, E. & Yee, H.-U.
Object Type: Report
System: The UNT Digital Library
COMPARISON OF RESULTS FOR QUARTER 1 SURFACE WATER SPLIT SAMPLES COLLECTED AT THE NUCLEAR FUEL SERVICES SITE ERWIN, TENNESSEE (open access)

COMPARISON OF RESULTS FOR QUARTER 1 SURFACE WATER SPLIT SAMPLES COLLECTED AT THE NUCLEAR FUEL SERVICES SITE ERWIN, TENNESSEE

Oak Ridge Associated Universities (ORAU), under the Oak Ridge Institute for Science and Education (ORISE) contract, collected split surface water samples with Nuclear Fuel Services (NFS) representatives on August 22, 2012. Representatives from the U.S. Nuclear Regulatory Commission and Tennessee Department of Environment and Conservation were also in attendance. Samples were collected at four surface water stations, as required in the approved Request for Technical Assistance number 11-018. These stations included Nolichucky River upstream (NRU), Nolichucky River downstream (NRD), Martin Creek upstream (MCU), and Martin Creek downstream (MCD). Both ORAU and NFS performed gross alpha and gross beta analyses. The comparison of results using the duplicate error ratio (DER), also known as the normalized absolute difference. A DER ≤ 3 indicates that, at a 99% confidence interval, split sample results do not differ significantly when compared to their respective one standard deviation (sigma) uncertainty. The NFS split sample report does not specify the confidence level of reported uncertainties. Therefore, standard two sigma reporting is assumed and uncertainty values were divided by 1.96. A comparison of split sample results, using the DER equation, indicates one set with a DER greater than 3. A DER of 3.1 is calculated for gross alpha …
Date: October 10, 2012
Creator: David A. King, CHP, PMP
Object Type: Report
System: The UNT Digital Library