Evaluation and Testing of the ADVANTG Code on SNM Detection (open access)

Evaluation and Testing of the ADVANTG Code on SNM Detection

Pacific Northwest National Laboratory (PNNL) has been tasked with evaluating the effectiveness of ORNL’s new hybrid transport code, ADVANTG, on scenarios of interest to our NA-22 sponsor, specifically of detection of diversion of special nuclear material (SNM). PNNL staff have determined that acquisition and installation of ADVANTG was relatively straightforward for a code in its phase of development, but probably not yet sufficient for mass distribution to the general user. PNNL staff also determined that with little effort, ADVANTG generated weight windows that typically worked for the problems and generated results consistent with MCNP. With slightly greater effort of choosing a finer mesh around detectors or sample reaction tally regions, the figure of merit (FOM) could be further improved in most cases. This does take some limited knowledge of deterministic transport methods. The FOM could also be increased by limiting the energy range for a tally to the energy region of greatest interest. It was then found that an MCNP run with the full energy range for the tally showed improved statistics in the region used for the ADVANTG run. The specific case of interest chosen by the sponsor is the CIPN project from Las Alamos National Laboratory (LANL), which …
Date: September 24, 2013
Creator: Shaver, Mark W.; Casella, Andrew M.; Wittman, Richard S. & Hayes, John W.
Object Type: Report
System: The UNT Digital Library
LEEM investigations of clean surfaces driven by energetic ion beams (open access)

LEEM investigations of clean surfaces driven by energetic ion beams

The original purpose of this award was to use low‐energy electron microscopy (LEEM) to explore the dynamics of surfaces of clean single crystal surfaces when driven by a beam of energetic ions. The goal was to understand the nanoscience of hyperthermal growth, surface erosion by sublimation and irradiation, operation of surface sinks in irradiated materials, diffusion on driven surfaces, and the creation of structural patterns. This project was based on a novel LEEM system constructed by C. P. Flynn, which provided real‐time imaging of surface dynamics by scattering low energy electrons. With the passing of Prof. Flynn in late 2011, this project was completed under a slightly different scope by constructing a low‐energy, inelastic electron scattering (�EELS�) instrument. Consistent with Flynn�s original objectives for his LEEM system, this device probes the dynamics of crystal surfaces. However the measurements are not carried out in real time, but instead are done in the frequency domain, through the energy lost from the probe electrons. The purpose of this device is to study the collective bosonic excitations in a variety of materials, including high temperature superconductors, topological insulators, carbon allotropes including (but not limited to) graphene, etc. The ultimate goal here is to identify …
Date: April 24, 2013
Creator: Abbamonte, Peter M.
Object Type: Report
System: The UNT Digital Library
Optimization of Triplet Quadrupoles Field Quality for the LHC High Luminosity Lattice at Collision Energy (open access)

Optimization of Triplet Quadrupoles Field Quality for the LHC High Luminosity Lattice at Collision Energy

None
Date: May 24, 2013
Creator: Nosochkov, Y.; Cai, Y.; Wang, M. H.; Fartoukh, S.; Giovannozzi, M.; De Maria, R. et al.
Object Type: Article
System: The UNT Digital Library
Flow Shear Effects in the Onset Physics of Resistive MHD Instabilities in Tokamaks. Final report (open access)

Flow Shear Effects in the Onset Physics of Resistive MHD Instabilities in Tokamaks. Final report

The progress in this research centers around the computational analysis of flow shear effects in the onset of a 3/2 mode driven by a 1/1 mode in DIII-D equilibria. The initial idea was to try and calculate, via nonlinear simulations with NIMROD, the effects of rotation shear on driven 3/2 and 2/1 seed island physics, in experimentally relevant DIIID equilibria. The simulations indicated that very small seed islands were directly driven, as shielding between the sawtooth and the surfaces is significant at the high Lundquist numbers of the experiment. Instead, long after the initial crash the difference in linear stability of the 3/2, which remained prevalent despite the flattening of the core profiles from the sawtooth, contributed to a difference in the eventual seed island evolution. Essentially the seed islands grew or decayed long after the sawtooth crash, and not directly from it. Effectively the dominant 1/1 mode was found to be dragging the coupled modes surrounding it at a high rate through the plasma at their surfaces. The 1/1 mode is locked to the local frame of the plasma in the core, where the flow rate is greatest. The resonant perturbations at the surrounding surfaces propagate in the 'high …
Date: April 24, 2013
Creator: Brennan, Dylan P.
Object Type: Report
System: The UNT Digital Library
Optimization Studies for ISOL Type High-Powered Targets (open access)

Optimization Studies for ISOL Type High-Powered Targets

The research studied one-step and two-step Isotope Separation on Line (ISOL) targets for future radioactive beam facilities with high driver-beam power through advanced computer simulations. As a target material uranium carbide in the form of foils was used because of increasing demand for actinide targets in rare-isotope beam facilities and because such material was under development in ISAC at TRIUMF when this project started. Simulations of effusion were performed for one-step and two step targets and the effects of target dimensions and foil matrix were studied. Diffusion simulations were limited by availability of diffusion parameters for UCx material at reduced density; however, the viability of the combined diffusion?effusion simulation methodology was demonstrated and could be used to extract physical parameters such as diffusion coefficients and effusion delay times from experimental isotope release curves. Dissipation of the heat from the isotope-producing targets is the limiting factor for high-power beam operation both for the direct and two-step targets. Detailed target models were used to simulate proton beam interactions with the targets to obtain the fission rates and power deposition distributions, which were then applied in the heat transfer calculations to study the performance of the targets. Results indicate that a direct target, …
Date: September 24, 2013
Creator: Remec, Igor & Ronningen, Reginald Martin
Object Type: Report
System: The UNT Digital Library
A PIC-Fluid Hybrid Algorithm for Multi-scale Simulations of Laser-plasma Interactions (open access)

A PIC-Fluid Hybrid Algorithm for Multi-scale Simulations of Laser-plasma Interactions

None
Date: June 24, 2013
Creator: Cohen, B I; Dimits, A M; Fiuza, F; Kemp, A & Strozzi, D
Object Type: Article
System: The UNT Digital Library
Compositional threshold for Nuclear Waste Glass Durability (open access)

Compositional threshold for Nuclear Waste Glass Durability

Within the composition space of glasses, a distinct threshold appears to exist that separates "good" glasses, i.e., those which are sufficiently durable, from "bad" glasses of a low durability. The objective of our research is to clarify the origin of this threshold by exploring the relationship between glass composition, glass structure and chemical durability around the threshold region.
Date: April 24, 2013
Creator: Kruger, Albert A.; Farooqi, Rahmatullah & Hrma, Pavel R.
Object Type: Article
System: The UNT Digital Library
Ground Source Integrated Heat Pump (GS-IHP) Development (open access)

Ground Source Integrated Heat Pump (GS-IHP) Development

Between October 2008 and May 2013 ORNL and ClimateMaster, Inc. (CM) engaged in a Cooperative Research and Development Agreement (CRADA) to develop a groundsource integrated heat pump (GS-IHP) system for the US residential market. A initial prototype was designed and fabricated, lab-tested, and modeled in TRNSYS (SOLAR Energy Laboratory, et al, 2010) to predict annual performance relative to 1) a baseline suite of equipment meeting minimum efficiency standards in effect in 2006 (combination of air-source heat pump (ASHP) and resistance water heater) and 2) a state-of-the-art (SOA) two-capacity ground-source heat pump with desuperheater water heater (WH) option (GSHPwDS). Predicted total annual energy savings, while providing space conditioning and water heating for a 2600 ft{sup 2} (242 m{sup 2}) house at 5 U.S. locations, ranged from 52 to 59%, averaging 55%, relative to the minimum efficiency suite. Predicted energy use for water heating was reduced 68 to 78% relative to resistance WH. Predicted total annual savings for the GSHPwDS relative to the same baseline averaged 22.6% with water heating energy use reduced by 10 to 30% from desuperheater contributions. The 1st generation (or alpha) prototype design for the GS-IHP was finalized in 2010 and field test samples were fabricated for testing …
Date: May 24, 2013
Creator: Baxter, V. D.; Rice, K.; Murphy, R.; Munk, J.; Ally, Moonis; Shen, Bo et al.
Object Type: Report
System: The UNT Digital Library
Ultrafast probing of the x-ray-induced lattice and electron dynamics in graphite at atomic-resolution (open access)

Ultrafast probing of the x-ray-induced lattice and electron dynamics in graphite at atomic-resolution

None
Date: January 24, 2013
Creator: Hau-Riege, S.
Object Type: Report
System: The UNT Digital Library
Physiochemical Evidence of Faulting Processes and Modeling of Fluid in Evolving Fault Systems in Southern California (open access)

Physiochemical Evidence of Faulting Processes and Modeling of Fluid in Evolving Fault Systems in Southern California

Our study targets recent (Plio-Pleistocene) faults and young (Tertiary) petroleum fields in southern California. Faults include the Refugio Fault in the Transverse Ranges, the Ellwood Fault in the Santa Barbara Channel, and most recently the Newport- Inglewood in the Los Angeles Basin. Subsurface core and tubing scale samples, outcrop samples, well logs, reservoir properties, pore pressures, fluid compositions, and published structural-seismic sections have been used to characterize the tectonic/diagenetic history of the faults. As part of the effort to understand the diagenetic processes within these fault zones, we have studied analogous processes of rapid carbonate precipitation (scaling) in petroleum reservoir tubing and manmade tunnels. From this, we have identified geochemical signatures in carbonate that characterize rapid CO2 degassing. These data provide constraints for finite element models that predict fluid pressures, multiphase flow patterns, rates and patterns of deformation, subsurface temperatures and heat flow, and geochemistry associated with large fault systems.
Date: May 24, 2013
Creator: Boles, James
Object Type: Report
System: The UNT Digital Library
Radiation Detection Computational Benchmark Scenarios (open access)

Radiation Detection Computational Benchmark Scenarios

Modeling forms an important component of radiation detection development, allowing for testing of new detector designs, evaluation of existing equipment against a wide variety of potential threat sources, and assessing operation performance of radiation detection systems. This can, however, result in large and complex scenarios which are time consuming to model. A variety of approaches to radiation transport modeling exist with complementary strengths and weaknesses for different problems. This variety of approaches, and the development of promising new tools (such as ORNL’s ADVANTG) which combine benefits of multiple approaches, illustrates the need for a means of evaluating or comparing different techniques for radiation detection problems. This report presents a set of 9 benchmark problems for comparing different types of radiation transport calculations, identifying appropriate tools for classes of problems, and testing and guiding the development of new methods. The benchmarks were drawn primarily from existing or previous calculations with a preference for scenarios which include experimental data, or otherwise have results with a high level of confidence, are non-sensitive, and represent problem sets of interest to NA-22. From a technical perspective, the benchmarks were chosen to span a range of difficulty and to include gamma transport, neutron transport, or both …
Date: September 24, 2013
Creator: Shaver, Mark W.; Casella, Andrew M.; Wittman, Richard S. & McDonald, Ben S.
Object Type: Report
System: The UNT Digital Library
Transforming the representation of the boundary layer and low clouds for high-resolution regional climate modeling: Final report (open access)

Transforming the representation of the boundary layer and low clouds for high-resolution regional climate modeling: Final report

Stratocumulus and shallow cumulus clouds in subtropical oceanic regions (e.g., Southeast Pacific) cover thousands of square kilometers and play a key role in regulating global climate (e.g., Klein and Hartmann, 1993). Numerical modeling is an essential tool to study these clouds in regional and global systems, but the current generation of climate and weather models has difficulties in representing them in a realistic way (e.g., Siebesma et al., 2004; Stevens et al., 2007; Teixeira et al., 2011). While numerical models resolve the large-scale flow, subgrid-scale parameterizations are needed to estimate small-scale properties (e.g. boundary layer turbulence and convection, clouds, radiation), which have significant influence on the resolved scale due to the complex nonlinear nature of the atmosphere. To represent the contribution of these fine-scale processes to the resolved scale, climate models use various parameterizations, which are the main pieces in the model that contribute to the low clouds dynamics and therefore are the major sources of errors or approximations in their representation. In this project, we aim to 1) improve our understanding of the physical processes in thermal circulation and cloud formation, 2) examine the performance and sensitivity of various parameterizations in the regional weather model (Weather Research and Forecasting …
Date: July 24, 2013
Creator: Huang, Hsin-Yuan & Hall, Alex
Object Type: Report
System: The UNT Digital Library
Intensity Frontier Instrumentation (open access)

Intensity Frontier Instrumentation

The fundamental origin of flavor in the Standard Model (SM) remains a mystery. Despite the roughly eighty years since Rabi asked “Who ordered that?” upon learning of the discovery of the muon, we have not understood the reason that there are three generations or, more recently, why the quark and neutrino mixing matrices and masses are so different. The solution to the flavor problem would give profound insights into physics beyond the Standard Model (BSM) and tell us about the couplings and the mass scale at which the next level of insight can be found. The SM fails to explain all observed phenomena: new interactions and yet unseen particles must exist. They may manifest themselves by causing SM reactions to differ from often very precise predictions. The Intensity Frontier (1) explores these fundamental questions by searching for new physics in extremely rare processes or those forbidden in the SM. This often requires massive and/or extremely finely tuned detectors.
Date: September 24, 2013
Creator: S., Kettell; Rameika, R. & Tshirhart, B.
Object Type: Report
System: The UNT Digital Library
CHARACTERIZATION OF GLOVEBOX GLOVES FOR THE SAVANNAH RIVER SITE (open access)

CHARACTERIZATION OF GLOVEBOX GLOVES FOR THE SAVANNAH RIVER SITE

A task was undertaken to characterize glovebox gloves that are currently used in the facilities at Savannah River Site (SRS) as well as some experimental and advanced compound gloves that have been proposed for use. Gloves from four manufacturers were tested for permeation in hydrogen and air, thermal stability, tensile properties, puncture resistance and dynamic mechanical response. The gloves were compared to each other within the type and also to the butyl rubber glove that is widely used at the SRS. The permeation testing demonstrated that the butyl compounds from three of the vendors behaved similarly and exhibited hydrogen permeabilities of .52‐.84 x10{sup ‐7} cc H{sub 2}*cm / (cm{sup 2}*atm). The Viton� glove performed at the lower edge of this bound, while the more advanced composite gloves exhibited permeabilities greater than a factor of two compared to butyl. Thermogravimetric analysis was used to determine the amount of material lost under slightly aggressive conditions. Glove losses are important since they can affect the life of glovebox stripper systems. During testing at 90, 120, and 150�C, the samples lost most of the mass in the initial 60 minutes of thermal exposure and as expected increasing the temperature increased the mass loss and …
Date: January 24, 2013
Creator: Korinko, P.
Object Type: Article
System: The UNT Digital Library
A Programming Framework for Scientific Applications on CPU-GPU Systems (open access)

A Programming Framework for Scientific Applications on CPU-GPU Systems

At a high level, my research interests center around designing, programming, and evaluating computer systems that use new approaches to solve interesting problems. The rapid change of technology allows a variety of different architectural approaches to computationally difficult problems, and a constantly shifting set of constraints and trends makes the solutions to these problems both challenging and interesting. One of the most important recent trends in computing has been a move to commodity parallel architectures. This sea change is motivated by the industry’s inability to continue to profitably increase performance on a single processor and instead to move to multiple parallel processors. In the period of review, my most significant work has been leading a research group looking at the use of the graphics processing unit (GPU) as a general-purpose processor. GPUs can potentially deliver superior performance on a broad range of problems than their CPU counterparts, but effectively mapping complex applications to a parallel programming model with an emerging programming environment is a significant and important research problem.
Date: March 24, 2013
Creator: Owens, John
Object Type: Report
System: The UNT Digital Library
Bounding the Higgs Width Through Interferometry (open access)

Bounding the Higgs Width Through Interferometry

None
Date: May 24, 2013
Creator: Dixon, Lance J. & Li, Ye
Object Type: Article
System: The UNT Digital Library
Challenges to the 2015 NPT Review Conference (open access)

Challenges to the 2015 NPT Review Conference

N/A
Date: May 24, 2013
Creator: S., Burk
Object Type: Report
System: The UNT Digital Library
Energy Savings for Occupancy-Based Control (OBC) of Variable-Air-Volume (VAV) Systems (open access)

Energy Savings for Occupancy-Based Control (OBC) of Variable-Air-Volume (VAV) Systems

This study evaluates the savings potential of occupancy based control (OBC) for large office buildings with VAV terminal boxes installed.
Date: January 24, 2013
Creator: Zhang, Jian; Lutes, Robert G.; Liu, Guopeng & Brambley, Michael R.
Object Type: Report
System: The UNT Digital Library
Cosmic Ray Studies with the Fermi Gamma-ray Space Telescope Large Area Telescope (open access)

Cosmic Ray Studies with the Fermi Gamma-ray Space Telescope Large Area Telescope

None
Date: April 24, 2013
Creator: Thompson, D. J.; Baldini, L. & Uchiyama, Y.
Object Type: Article
System: The UNT Digital Library
Beam Ion Instability in SPEAR3: Measurements, Analyses and Simulations (open access)

Beam Ion Instability in SPEAR3: Measurements, Analyses and Simulations

None
Date: June 24, 2013
Creator: Wang, L.; Safranek, J.; Cai, Y.; Corbett, J.; Hettel, B.; Raubenheimer, T.O. et al.
Object Type: Article
System: The UNT Digital Library
Laboratory Report on Performance Evaluation of Key Constituents during Pre-Treatment of High Level Waste Direct Feed (open access)

Laboratory Report on Performance Evaluation of Key Constituents during Pre-Treatment of High Level Waste Direct Feed

The analytical capabilities of the 222-S Laboratory are tested against the requirements for an optional start up scenario of the Waste Treatment and Immobilization Plant on the Hanford Site. In this case, washed and in-tank leached sludge would be sent directly to the High Level Melter, bypassing Pretreatment. The sludge samples would need to be analyzed for certain key constituents in terms identifying melter-related issues and adjustment needs. The analyses on original tank waste as well as on washed and leached material were performed using five sludge samples from tanks 241-AY-102, 241-AZ-102, 241-AN-106, 241-AW-105, and 241-SY-102. Additionally, solid phase characterization was applied to determine the changes in mineralogy throughout the pre-treatment steps.
Date: June 24, 2013
Creator: Huber, Heinz J.
Object Type: Report
System: The UNT Digital Library
Discovery Searches for Light New Physics with BaBar (open access)

Discovery Searches for Light New Physics with BaBar

None
Date: May 24, 2013
Creator: Lopez-March, Neus
Object Type: Article
System: The UNT Digital Library
Properties of Alfven Eigenmodes in the TAE range on the National Spherical Torus Experiment-Upgrade (open access)

Properties of Alfven Eigenmodes in the TAE range on the National Spherical Torus Experiment-Upgrade

A second Neutral Beam (NB) injection line is being installed on the NSTX Upgrade device, resulting in six NB sources with di erent tangency radii that will be available for heating and current drive. This work explores the properties of instabilities in the frequency range of the Toroidal Alfv#19;en Eigenmode (TAE) for NSTX-U scenarios with various NB injection geometries, from more perpendicular to more tangential, and with increased toroidal magnetic eld with respect to previous NSTX scenarios. Predictions are based on analysis through the ideal MHD code NOVA-K. For the scenarios considered in this work, modi cations of the Alfv#19;en continuum result in a frequency upshift and a broadening of the radial mode structure. The latter e ect may have consequences for fast ion transport and loss. Preliminary stability considerations indicate that TAEs are potentially unstable, with ion Landau damping representing the dominant damping mechanism
Date: April 24, 2013
Creator: unknown
Object Type: Report
System: The UNT Digital Library
redMaPPer II: X-ray and SZ Performance Benchmarks for the SDSS Catalog (open access)

redMaPPer II: X-ray and SZ Performance Benchmarks for the SDSS Catalog

None
Date: April 24, 2013
Creator: Rozo, Eduardo & Rykoff, Eli S.
Object Type: Article
System: The UNT Digital Library