Research on CdZnTe and Other Novel Room Temperature Gamma Ray Spectrometer Materials (open access)

Research on CdZnTe and Other Novel Room Temperature Gamma Ray Spectrometer Materials

Room temperature gamma-ray spectrometers are being developed for a number of years for national security applications where high sensitivity, low operating power and compactness are indispensable. The technology has matured now to the point where large volume (several cubic centimeters) and high energy resolution (approximately 1% at 660 eV) of gamma photons, are becoming available for their incorporation into portable systems for remote sensing of signatures from nuclear materials.
Date: May 5, 2007
Creator: Burger, Arnold; Groza, Michael; Cui, Yunlong; Roy, Utpal N. & Guo, M.
Object Type: Report
System: The UNT Digital Library
Record of Decision for Tank Farm Soil and INTEC Groundwater, Operable Unit 3-14 (open access)

Record of Decision for Tank Farm Soil and INTEC Groundwater, Operable Unit 3-14

This decision document presents the selected remedy for Operable Unit (OU) 3-14 tank farm soil and groundwater at the Idaho Nuclear Technology and Engineering Center (INTEC), which is located on the Idaho National Laboratory (INL) Site. The tank farm was initially evaluated in the OU 3-13 Record of Decision (ROD), and it was determined that additional information was needed to make a final decision. Additional information has been obtained on the nature and extent of contamination in the tank farm and on the impact to groundwater. The selected remedy was chosen in accordance with the Comprehensive Environmental Response, Liability and Compensation Act of 1980 (CERCLA) (42 USC 9601 et seq.), as amended by the Superfund Amendments and Reauthorization Act of 1986 (Public Law 99-499) and the National Oil and Hazardous Substances Pollution Contingency Plan (40 CFR 300). The selected remedy is intended to be the final action for tank farm soil and groundwater at INTEC. The response action selected in this ROD is necessary to protect the public health, welfare, or the environment from actual or threatened releases of hazardous substances into the environment. Such a release or threat of release may present an imminent and substantial endangerment to public …
Date: May 16, 2007
Creator: Cahn, L. S.
Object Type: Report
System: The UNT Digital Library
Record of Decision Tank Farm Soil and INTEC Groundwater (open access)

Record of Decision Tank Farm Soil and INTEC Groundwater

This decision document presents the selected remedy for Operable Unit (OU) 3-14 tank farm soil and groundwater at the Idaho Nuclear Technology and Engineering Center (INTEC), which is located on the Idaho National Laboratory (INL) Site. The tank farm was initially evaluated in the OU 3-13 Record of Decision (ROD), and it was determined that additional information was needed to make a final decision. Additional information has been obtained on the nature and extent of contamination in the tank farm and on the impact of groundwater. The selected remedy was chosen in accordance with the Comprehensive Environmental Response, Liability and Compensation Act of 1980 (CERCLA) (42 USC 9601 et seq.), as amended by the Superfund Amendments and Reauthorization Act of 1986 (Public Law 99-499) and the National Oil and Hazardous Substances Pollution Contingency Plan (40 CFR 300). The selected remedy is intended to be the final action for tank far soil and groundwater at INTEC.
Date: May 1, 2007
Creator: Cahn, L. S.
Object Type: Report
System: The UNT Digital Library
CDZNTE ROOM-TEMPERATURE SEMICONDUCTOR GAMMA-RAY DETECTOR FOR NATIONAL-SECURITY APPLICATIONS. (open access)

CDZNTE ROOM-TEMPERATURE SEMICONDUCTOR GAMMA-RAY DETECTOR FOR NATIONAL-SECURITY APPLICATIONS.

One important mission of the Department of Energy's National Nuclear Security Administration is to develop reliable gamma-ray detectors to meet the widespread needs of users for effective techniques to detect and identify special nuclear- and radioactive-materials. Accordingly, the Nonproliferation and National Security Department at Brookhaven National Laboratory was tasked to evaluate existing technology and to develop improved room-temperature detectors based on semiconductors, such as CdZnTe (CZT). Our research covers two important areas: Improving the quality of CZT material, and exploring new CZT-based gamma-ray detectors. In this paper, we report on our recent findings from the material characterization and tests of actual CZT devices fabricated in our laboratory and from materials/detectors supplied by different commercial vendors. In particular, we emphasize the critical role of secondary phases in the current CZT material and issues in fabricating the CZT detectors, both of which affect their performance.
Date: May 4, 2007
Creator: Camarda, G. S.; Bolotnikov, A. E.; Cui, Y.; Hossain, A.; Kohman, K. T. & James, R. B.
Object Type: Article
System: The UNT Digital Library
Seismic velocity estimation from time migration (open access)

Seismic velocity estimation from time migration

This is concerned with imaging and wave propagation in nonhomogeneous media, and includes a collection of computational techniques, such as level set methods with material transport, Dijkstra-like Hamilton-Jacobi solvers for first arrival Eikonal equations and techniques for data smoothing. The theoretical components include aspects of seismic ray theory, and the results rely on careful comparison with experiment and incorporation as input into large production-style geophysical processing codes. Producing an accurate image of the Earth's interior is a challenging aspect of oil recovery and earthquake analysis. The ultimate computational goal, which is to accurately produce a detailed interior map of the Earth's makeup on the basis of external soundings and measurements, is currently out of reach for several reasons. First, although vast amounts of data have been obtained in some regions, this has not been done uniformly, and the data contain noise and artifacts. Simply sifting through the data is a massive computational job. Second, the fundamental inverse problem, namely to deduce the local sound speeds of the earth that give rise to measured reacted signals, is exceedingly difficult: shadow zones and complex structures can make for ill-posed problems, and require vast computational resources. Nonetheless, seismic imaging is a crucial part …
Date: May 31, 2007
Creator: Cameron, Maria Kourkina
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Thermal Effects on Thin Laser-Peened Ferritic-Martensitic Samples (open access)

Thermal Effects on Thin Laser-Peened Ferritic-Martensitic Samples

None
Date: May 17, 2007
Creator: Caro, M.; Zalesky, T.; Hosemann, P.; El-dasher, B. S.; Halsey, W. G. & Stuart, B.
Object Type: Report
System: The UNT Digital Library
The Performance Effect of Multi-core on ScientificApplications (open access)

The Performance Effect of Multi-core on ScientificApplications

The historical trend of increasing single CPU performancehas given way to roadmap of increasing core count. The challenge ofeffectively utilizing these multi-core chips is just starting to beexplored by vendors and application developers alike. In this study, wepresent some performance measurements of several complete scientificapplications on single and dual core Cray XT3 and XT4 systems with a viewto characterizing the effects of switching to multi-core chips. Weconsider effects within a node by using applications run at lowconcurrencies, and also effects on node-interconnect interaction usinghigher concurrency results. Finally, we construct a simple performancemodel based on the principle on-chip shared resource--memorybandwidth--and use this to predict the performance of the forthcomingquad-core system.
Date: May 14, 2007
Creator: Carter, Jonathan; He, Yun; Shalf, John; Shan, Hongzhang; Strohmaier, Erich & Wasserman, Harvey
Object Type: Article
System: The UNT Digital Library
ANALYSIS OF SPECIAL WASTE CONFIGURATIONS AT THE SRS WASTE MANAGEMENT FACILITIES (open access)

ANALYSIS OF SPECIAL WASTE CONFIGURATIONS AT THE SRS WASTE MANAGEMENT FACILITIES

Job Control Waste (JCW) at the Savannah River Site (SRS) Solid Waste Management Facilities (SWMF) may be disposed of in special containers, and the analysis of these containers requires developing specific analysis methodologies. A method has been developed for the routine assay of prohibited items (liquids, etc.) contained in a 30-gallon drum that is then placed into a 55-gallon drum. Method development consisted of system calibration with a NIST standard at various drum-to-detector distances, method verification with a liquid sample containing a known amount of Pu-238, and modeling the inner container using Ortec Isotopic software. Using this method for measurement of the known standard in the drum-in-drum configuration produced excellent agreement (within 15%) with the known value. Savannah River Site Solid Waste Management also requested analysis of waste contained in large black boxes (commonly 18-feet x 12-feet x 7-feet) stored at the SWMF. These boxes are frequently stored in high background areas and background radiation must be considered for each analysis. A detection limit of less than 150 fissile-gram-equivalents (FGE) of TRU waste is required for the black-box analyses. There is usually excellent agreement for the measurements at different distances and measurement uncertainties of about 50% are obtained at distances …
Date: May 14, 2007
Creator: Casella, V & Raymond Dewberry, R
Object Type: Article
System: The UNT Digital Library
TUNGSTEN SHIELDS FOR CS-137 INLINE MONITORS IN THE CAUSTIC SIDE SOLVENT EXTRACTION PROCESS (open access)

TUNGSTEN SHIELDS FOR CS-137 INLINE MONITORS IN THE CAUSTIC SIDE SOLVENT EXTRACTION PROCESS

The Department of Energy (DOE) selected Caustic-Side Solvent Extraction (CSSX) as the preferred technology for the removal of radioactive cesium from High-Level Waste (HLW) at the Savannah River Site (SRS). The CSSX process is a continuous process that uses a novel solvent to extract cesium from highly radioactive waste and concentrate it in dilute nitric acid. In-line analyses are performed with gamma-ray monitors to measure the C-137 concentration in the decontaminated salt solution (DSS) and in the strip effluent (SE). Sodium iodide (NaI) monitors are used to measure the Cs-137 concentration before the DSS Hold Tank, while Geiger-Mueller (GM) monitors are used for Cs-137 measurements before the SE hold tank. Tungsten shields were designed using Monte Carlo calculations and fabricated to provide the needed reduction of the process background radiation at the detector positions. A one-inch tungsten cylindrical shield reduced the background radiation by a factor of fifty that was adequate for the GM detectors, while a three-and-one-half-inch tungsten cylindrical shield was required for the NaI detectors. Testing of the NaI shield was performed at the SRS Instrument Calibration Facility. Based on this testing, the as-built shield is predicted to be able to detect the MCU DSS stream at concentrations …
Date: May 10, 2007
Creator: Casella, V; Mark Hogue, M; Javier Reyes-Jimenez, J; Paul Filpus-Luyckx, P; Timothy Riley, T; Fred Ogden, F et al.
Object Type: Article
System: The UNT Digital Library
ITER Shape Controller and Transport Simulations (open access)

ITER Shape Controller and Transport Simulations

We currently use the CORSICA integrated modeling code for scenario studies for both the DIII-D and ITER experiments. In these simulations, free- or fixed-boundary equilibria are simultaneously converged with thermal evolution determined from transport models providing temperature and current density profiles. Using a combination of fixed boundary evolution followed by free-boundary calculation to determine the separatrix and coil currents. In the free-boundary calculation, we use the state-space controller representation with transport simulations to provide feedback modeling of shape, vertical stability and profile control. In addition to a tightly coupled calculation with simulator and controller imbedded inside CORSICA, we also use a remote procedure call interface to couple the CORSICA non-linear plasma simulations to the controller environments developed within the Mathworks Matlab/Simulink environment. We present transport simulations using full shape and vertical stability control with evolution of the temperature profiles to provide simulations of the ITER controller and plasma response.
Date: May 31, 2007
Creator: Casper, T A; Meyer, W H; Pearlstein, L D & Portone, A
Object Type: Article
System: The UNT Digital Library
Chiral perturbation theory with tensor sources (open access)

Chiral perturbation theory with tensor sources

We construct the most general chirally-invariant Lagrangian for mesons in the presence of external sources coupled to the tensor current \bar psi sigma_mu nu psi. In order to have only even terms in the chiral expansion, we consider the new source of O(p2). With this choice, we build the even-parity effective Lagrangian up to the p6-order (NLO). While there are only 4 new terms at the p4-order, at p6-order we find 78 terms for n_f=2 and 113 terms for n_f=3. We provide a detailed discussion on the different mechanisms that ensure that our final set of operators is complete and non-redundant. We also examine the odd-parity sector, to conclude that the first operators appear at the p8-order (NNLO).
Date: May 21, 2007
Creator: Cata, Oscar; Cata, Oscar & Mateu, Vicent
Object Type: Article
System: The UNT Digital Library
Model-based Layer Estimation using a Hybrid Genetic/Gradient Search Optimization Algorithm (open access)

Model-based Layer Estimation using a Hybrid Genetic/Gradient Search Optimization Algorithm

A particle swarm optimization (PSO) algorithm is combined with a gradient search method in a model-based approach for extracting interface positions in a one-dimensional multilayer structure from acoustic or radar reflections. The basic approach is to predict the reflection measurement using a simulation of one-dimensional wave propagation in a multi-layer, evaluate the error between prediction and measurement, and then update the simulation parameters to minimize the error. Gradient search methods alone fail due to the number of local minima in the error surface close to the desired global minimum. The PSO approach avoids this problem by randomly sampling the region of the error surface around the global minimum, but at the cost of a large number of evaluations of the simulator. The hybrid approach uses the PSO at the beginning to locate the general area around the global minimum then switches to the gradient search method to zero in on it. Examples of the algorithm applied to the detection of interior walls of a building from reflected ultra-wideband radar signals are shown. Other possible applications are optical inspection of coatings and ultrasonic measurement of multilayer structures.
Date: May 17, 2007
Creator: Chambers, D.; Lehman, S. & Dowla, F.
Object Type: Article
System: The UNT Digital Library
Millisecond Kinetics of Nanocrystal Cation Exchange Using Microfluidic X-ray Absorption Spectroscopy (open access)

Millisecond Kinetics of Nanocrystal Cation Exchange Using Microfluidic X-ray Absorption Spectroscopy

We describe the use of a flow-focusing microfluidic reactorto measure the kinetics of theCdSe-to-Ag2Se nanocrystal cation exchangereaction using micro-X-ray absorption spectroscopy (mu XAS). The smallmicroreactor dimensions facilitate the millisecond mixing of CdSenanocrystal and Ag+ reactant solutions, and the transposition of thereaction time onto spatial coordinates enables the in situ observation ofthe millisecond reaction with mu XAS. XAS spectra show the progression ofCdSe nanocrystals to Ag2Se over the course of 100 ms without the presenceof long-lived intermediates. These results, along with supporting stoppedflow absorption experiments, suggest that this nanocrystal cationexchange reaction is highly efficient and provide insight into how thereaction progresses in individual particles. This experiment illustratesthe value and potential of in situ microfluidic X-ray synchrotrontechniques for detailed studies of the millisecond structuraltransformations of nanoparticles and other solution-phase reactions inwhich diffusive mixing initiates changes in local bond structures oroxidation states.
Date: May 7, 2007
Creator: Chan, Emory M.; Marcus, Matthew A.; Fakra, Sirine; Elnaggar, Mariam S.; Mathies, Richard A. & Alivisatos, A. Paul
Object Type: Article
System: The UNT Digital Library
Fuel Savings and Emission Reductions from Next-Generation Mobile Air Conditioning Technology in India: Preprint (open access)

Fuel Savings and Emission Reductions from Next-Generation Mobile Air Conditioning Technology in India: Preprint

This paper quantifies the mobile air-conditioning fuel consumption of the typical Indian vehicle, exploring potential fuel savings and emissions reductions these systems for the next generation of vehicles.
Date: May 1, 2007
Creator: Chaney, L.; Thundiyil, K.; Chidambaram, S.; Abbi, Y. P. & Anderson, S.
Object Type: Article
System: The UNT Digital Library
Cosmic Ray induced Neutron and Gamma-Ray bursts in a Lead Pile (open access)

Cosmic Ray induced Neutron and Gamma-Ray bursts in a Lead Pile

The neutron background is created primarily by cosmic rays interactions. Of particular interest for SNM detection is an understanding of burst events that resemble fission chains. We have been studying the interaction of cosmic rays with a lead pile that is efficient at creating neutron bursts from cosmic ray interactions. The neutron burst size depends on the configuration of the lead. We have found that the largest bursts appear to have been created by primaries of energy over 100 GeV that have had a diffractive interaction with the atmosphere. The large events trigger muon coincidence paddles with very high efficiency, and the resulting interactions with the lead pile can create over 10, 000 neutrons in a burst.
Date: May 8, 2007
Creator: Chapline, G; Hagmann, C; Kerr, P; Snyderman, N J & Wurtz, R
Object Type: Report
System: The UNT Digital Library
Measurement of CP-Violating Asymmetries in B0 to D(*)+D- (open access)

Measurement of CP-Violating Asymmetries in B0 to D(*)+D-

None
Date: May 11, 2007
Creator: Chen, C
Object Type: Article
System: The UNT Digital Library
FIRST Winged And X-Shaped Radio Source Candidates (open access)

FIRST Winged And X-Shaped Radio Source Candidates

A small number of double-lobed radio galaxies are found with an additional pair of extended low surface brightness 'wings' of emission giving them a distinctive 'X'-shaped appearance. One popular explanation for the unusual morphologies posits that the central supermassive black hole (SMBH)/accretion disk system underwent a recent realignment; in a merger scenario, the active lobes mark the post-merger axis of the resultant system (e.g., Merritt & Ekers 2002). However, this and other interpretations are not well tested on the few (about one dozen) known examples. In part to remedy this deficiency, a large sample of winged and X-shaped radio sources is being compiled for a systematic study. An initial sample of 100 new candidates is described as well as some of the follow-up work being pursued to test the different scenarios.
Date: May 30, 2007
Creator: Cheung, C.C.; /KIPAC, Menlo Park; Springmann, A. & /KIPAC, Menlo Park /Wellesley Coll.
Object Type: Article
System: The UNT Digital Library
Measurement of the Production Cross Section of Top Quark Pairs in the Lepton + Jets Channel at d0 and Atlas and Interpretation in Terms of Charged Higgs Boson at Atlas (open access)

Measurement of the Production Cross Section of Top Quark Pairs in the Lepton + Jets Channel at d0 and Atlas and Interpretation in Terms of Charged Higgs Boson at Atlas

None
Date: May 1, 2007
Creator: Chevallier, Florent & /LPSC, Grenoble
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Qualification of Automated Low-Field NMR Relaxometry for Quality Control of Polymers in a Production Setting (open access)

Qualification of Automated Low-Field NMR Relaxometry for Quality Control of Polymers in a Production Setting

Implementation of a low field time-domain NMR scanner as a diagnostic tool in the production of new polymer components is described in the context of qualification of a new QA/QC device. A study to determine the optimal experimental parameters was performed and a robotic autosampler was built to enable scanning of multiple pads. Relationships between T{sub 2} values and physical properties of DC745 slabs were investigated, and the appropriate sampling parameters for the production setting were determined. Two versions of a robotic autosampler were built, and for the component described here a fourth radial axis was required in addition to traditional X, Y, and Z movement to eliminate the large variability in T{sub 2} due to inconsistent sample coverage caused by complex rib geometry of the component. Data show that with appropriate choice of experimental conditions of the NMR detector and the detection geometry of the robotic autosampler, sufficient resolution of variations in crosslink density on the millimeter scale could be determined. All data to date demonstrates that low-field NMR devices are a feasible tool for use in production settings for non-destructive quality control of polymer components.
Date: May 11, 2007
Creator: Chinn, S; Cook-Tendulkar, A; Maxwell, R; Wheeler, H; Wilson, M & Xie, Z
Object Type: Article
System: The UNT Digital Library
Combustion Control and Diagnostics Sensor Testing in a Thermal Barrier Coated Combustor (open access)

Combustion Control and Diagnostics Sensor Testing in a Thermal Barrier Coated Combustor

The combustion control and diagnostics sensor (CCADS) continues to be developed as an in-situ combustion sensor, with immediate application to natural gas fired turbines. In-situ combustion monitoring is also expected to benefit advanced power plants of the future, fueled by coal-derived syngas, liquified natural gas (LNG), hydrogen, or hydrogen blend fuels. The in-situ monitoring that CCADS provides can enable the optimal operation of advanced, fuel-flexible turbines for minimal pollutant emissions and maximum efficiency over the full operating range of an advanced turbine. Previous work has demonstrated CCADS as a useful sensor for in-situ monitoring of natural gas combustion, including detection of important combustion events such as flashback and lean blowoff, in experimental combustors without thermal barrier coatings (TBC). Since typical TBC materials are electrical insulators at room temperature, and CCADS operation requires conduction of electrical current to the walls of the combustor, a TBC on the combustion liner was identified as a potential barrier to CCADS operation in commercial application. This paper reports on CCADS experiments in a turbulent lean premixed combustor with a yttria-stabilized zirconia (YSZ) thermal barrier coating on the combustor wall. The tests were conducted at 0.1 MPa (1 atm), with a 15V excitation voltage on the …
Date: May 1, 2007
Creator: Chorpening, B.T.; Dukes, M.G.; Robey, E.H. & Thornton, J.D.
Object Type: Article
System: The UNT Digital Library
Lawrence Livermore National Laboratory Annual Report 2006 (open access)

Lawrence Livermore National Laboratory Annual Report 2006

For the Laboratory and staff, 2006 was a year of outstanding achievements. As our many accomplishments in this annual report illustrate, the Laboratory's focus on important problems that affect our nation's security and our researchers breakthroughs in science and technology have led to major successes. As a national laboratory that is part of the Department of Energy's National Nuclear Security Administration (DOE/NNSA), Livermore is a key contributor to the Stockpile Stewardship Program for maintaining the safety, security, and reliability of the nation's nuclear weapons stockpile. The program has been highly successful, and our annual report features some of the Laboratory's significant stockpile stewardship accomplishments in 2006. A notable example is a long-term study with Los Alamos National Laboratory, which found that weapon pit performance will not sharply degrade from the aging effects on plutonium. The conclusion was based on a wide range of nonnuclear experiments, detailed simulations, theoretical advances, and thorough analyses of the results of past nuclear tests. The study was a superb scientific effort. The continuing success of stockpile stewardship enabled NNSA in 2006 to lay out Complex 2030, a vision for a transformed nuclear weapons complex that is more responsive, cost efficient, and highly secure. One of …
Date: May 24, 2007
Creator: Chrzanowski, P & Walter, K
Object Type: Report
System: The UNT Digital Library
Measurement of the W-boson helicity fractions in top-quark decays at CDF (open access)

Measurement of the W-boson helicity fractions in top-quark decays at CDF

We present a measurement of the fractions F{sub 0} and F{sub +} of longitudinally polarized and right-handed W bosons in top-quark decays using data collected with the CDF II detector. The data set used in the analysis corresponds to an integrated luminosity of approximately 955 pb{sup -1}. We select t{bar t} candidate events with one lepton, at least four jets, and missing transverse energy. Our helicity measurement uses the decay angle {theta}*, which is defined as the angle between the momentum of the charged lepton in the W boson rest-frame and the W momentum in the top-quark rest-frame. The cos{theta}* distribution in the data is determined by full kinematic reconstruction of the t{bar t} candidates. We find F{sub 0}= 0.59 {+-} 0.12(stat){sup +0.07}{sub -0.06}(syst) and F{sub +}=-0.03 {+-} 0.06(stat){sup +0.04}{sub -0.03}(syst), which is consistent with the standard model prediction. We set an upper limit on the fraction of right-handed W bosons of F{sub +} {le} 0.10 at the 95% confidence level.
Date: May 1, 2007
Creator: Chwalek, Thorsten
Object Type: Article
System: The UNT Digital Library
Model-Based Algorithms for Detecting Cable Damage from Time-Domain Reflectomertry Measurements (open access)

Model-Based Algorithms for Detecting Cable Damage from Time-Domain Reflectomertry Measurements

None
Date: May 3, 2007
Creator: Clark, G A
Object Type: Article
System: The UNT Digital Library
Some Basic Research Problems Related to Energy (open access)

Some Basic Research Problems Related to Energy

This paper discusses work on correlation functions in hard sphere fluids, colloidal suspension and Lorentz lattice gas cellular automata. (LSP)
Date: May 1, 2007
Creator: Cohen, E.G.D.
Object Type: Report
System: The UNT Digital Library