Abstract - INMM Annual Meeting 1998 Status of Underground Testing Program (open access)

Abstract - INMM Annual Meeting 1998 Status of Underground Testing Program

This report is about the INMM Annual Meeting 1998 Status of Underground Testing Program.
Date: February 5, 2008
Creator: Dr. William J. Boyle, Larry R. Hayes, Alan J. Mitchell
Object Type: Article
System: The UNT Digital Library
Advanced Large Area Plastic Scintillator Project (ALPS): Final Report (open access)

Advanced Large Area Plastic Scintillator Project (ALPS): Final Report

The advanced Large-Area Plastic Scintillator (ALPS) Project at Pacific Northwest National Laboratory investigated possible technological avenues for substantially advancing the state-of-the-art in gamma-ray detection via large-area plastic scintillators. The three predominant themes of these investigations comprised the following: * Maximizing light collection efficiency from a single large-area sheet of plastic scintillator, and optimizing hardware event trigger definition to retain detection efficiency while exploiting the power of coincidence to suppress single-PMT "dark current" background; * Utilizing anti-Compton vetoing and supplementary spectral information from a co-located secondary, or "Back" detector, to both (1) minimize Compton background in the low-energy portion of the "Front" scintillator's pulse-height spectrum, and (2) sharpen the statistical accuracy of the front detector's low-energy response prediction as impelmented in suitable energy-windowing algorithms; and * Investigating alternative materials to enhance the intrinsic gamma-ray detection efficiency of plastic-based sensors.
Date: February 5, 2008
Creator: Jordan, David V.; Reeder, Paul L.; Todd, Lindsay C.; Warren, Glen A.; McCormick, Kathleen R.; Stephens, Daniel L. et al.
Object Type: Report
System: The UNT Digital Library
Compound-Nucleus Formation Following Direct Interactions to Highly-Excited Final States (open access)

Compound-Nucleus Formation Following Direct Interactions to Highly-Excited Final States

When direct reactions populate highly excited, unbound configurations in the residual nucleus, the nucleus may further evolve into a compound nucleus. Alternatively, the residual system may decay by emitting particles into the continuum. Understanding the relative weights of these two processes as a function of the angular momentum and parity deposited in the nucleus is important for the surrogate-reaction technique. A particularly interesting case is compound-nucleus formation via the (d, p) reaction, which may be a useful tool for forming compound nuclei off the valley of stability in inverse-kinematics experiments. We present here a study of the compound formation probability for a closely-related direct reaction, direct-semidirect radiative neutron capture.
Date: February 5, 2008
Creator: Dietrich, F S
Object Type: Article
System: The UNT Digital Library
Development of a New Stratigraphic Trap Exploration Using Elastic-Wave Seismic Technology (open access)

Development of a New Stratigraphic Trap Exploration Using Elastic-Wave Seismic Technology

Vecta acquired 9 square miles of 9-C seismic data in Mountrail County, North Dakota with the Mission Canyon shoreline as a primary target. Vecta contracted the Institute Francais du Petrole in order to co-develop a more rigorous multicomponent seismic interpretation product. The final interpretation was very unique in that it utilized not only the 9-C seismic data but also the new jointly developed software. A Mission Canyon anomaly was developed in 2006; however, it was of insufficient size to be a commercial target at the time. Therefore, Vecta analyzed the shear data for anisotropy within the Bakken formation and successfully reentered an abandoned producer within the project area and drilled a horizontal leg through the anomalous zones of the middle member of the Bakken formation. The well was open hole completed, swab tested, sand fraced, and swab tested some more. No shows of oil were ever seen from the Bakken formation, but the well yielded considerable amounts of formation water. The well has been abandoned as non-commercial. From the swab tests, one may conclude considerable permeability exists in the formation, thus confirming the utility of the shear wave to detect fractures within the targeted formation.
Date: February 5, 2008
Creator: DeVault, Bryan
Object Type: Report
System: The UNT Digital Library
FY07 LDRD Final Report A Fracture Mechanics and Tribology Approach to Understanding Subsurface Damage on Fused Silica during Grinding and Polishing (open access)

FY07 LDRD Final Report A Fracture Mechanics and Tribology Approach to Understanding Subsurface Damage on Fused Silica during Grinding and Polishing

The objective of this work is to develop a solid scientific understanding of the creation and characteristics of surface fractures formed during the grinding and polishing of brittle materials, specifically glass. In this study, we have experimentally characterized the morphology, number density, and depth distribution of various surface cracks as a function of various grinding and polishing processes (blanchard, fixed abrasive grinding, loose abrasive, pitch polishing and pad polishing). Also, the effects of load, abrasive particle (size, distribution, foreign particles, geometry, velocity), and lap material (pitch, pad) were examined. The resulting data were evaluated in terms of indentation fracture mechanics and tribological interactions (science of interacting surfaces) leading to several models to explain crack distribution behavior of ground surfaces and to explain the characteristics of scratches formed during polishing. This project has greatly advanced the scientific knowledge of microscopic mechanical damage occurring during grinding and polishing and has been of general interest. This knowledge-base has also enabled the design and optimization of surface finishing processes to create optical surfaces with far superior laser damage resistance. There are five major areas of scientific progress as a result of this LDRD. They are listed in Figure 1 and described briefly in this …
Date: February 5, 2008
Creator: Suratwala, T I; Miller, P E; Menapace, J A; Wong, L L; Steele, R A; Feit, M D et al.
Object Type: Report
System: The UNT Digital Library
Initial MAR Assessments to Access the Impact of Al-Dissolution on DWPF Operating Windows (open access)

Initial MAR Assessments to Access the Impact of Al-Dissolution on DWPF Operating Windows

SRNL was tasked to provide an assessment of the downstream impacts (or lack thereof) to DWPF of decisions regarding the implementation of Al-dissolution to support sludge mass reduction and processing. Based on future sludge batch compositional projections, assessments have been made with respect to the ability to maintain comparable projected operating windows for sludges with high temperature Al-dissolution and without Al-dissolution. In general, paper study assessments indicated that most of the future sludge batches (twelve with and fourteen without high temperature Al-dissolution) had multiple frits available that yielded relatively large operating windows. The projected operating windows were defined by the waste loading (WL) interval over which glasses were classified as acceptable based on current process control models and their related constraints. Although multiple frits were identified, using a 17-point width as a general guide for a reasonable operating window (e.g., 25-41% WL), there generally appeared to be more flexibility in frit selection for the without Al-dissolution flowsheets. This larger frit compositional platform could allow frit development efforts to make more significant adjustments to melt rate. However, based on the general observations of the paper study, there is essentially no clear distinction between the two options with which to drive a …
Date: February 5, 2008
Creator: Newell, J. D.; Edwards, T. B. & Peeler, D. K.
Object Type: Report
System: The UNT Digital Library
INL SITEWIDE INSTITUTIONAL CONTROLS, AND OPERATIONS AND MAINTENANCE PLAN FOR CERCLA RESPONSE ACTIONS (open access)

INL SITEWIDE INSTITUTIONAL CONTROLS, AND OPERATIONS AND MAINTENANCE PLAN FOR CERCLA RESPONSE ACTIONS

On November 9, 2002, the U.S. Environmental Protection Agency, the U.S. Department of Energy, and the Idaho Department of Environmental Quality approved the 'Record of Decision Experimental Breeder Reactor-I/Boiling Water Reactor Experiment Area and Miscellaneous Sites', which required a Site-wide institutional controls plan for the then Idaho National Engineering and Environmental Laboratory (now known as the Idaho National Laboratory). This document, first issued in June 2004, fulfilled that requirement. This revision identifies and consolidates the institutional controls and operations and maintenance requirements into a single document.
Date: February 5, 2008
Creator: Jolley, Wendell L.
Object Type: Report
System: The UNT Digital Library
Non-magnetic compensation in ferromagnetic Ga1-xMnxAs and Ga1-xMnxP synthesized by ion implantation and pulsed-laser melting (open access)

Non-magnetic compensation in ferromagnetic Ga1-xMnxAs and Ga1-xMnxP synthesized by ion implantation and pulsed-laser melting

The electronic and magnetic effects of intentional compensation with non-magnetic donors are investigated in the ferromagnetic semiconductors Ga1-xMnxAs and Ga1-xMnxP synthesized using ion implantation and pulsed-laser melting (II-PLM). It is demonstrated that compensation with non-magnetic donors and MnI have similarqualitative effects on materials properties. With compensation TC decreases, resistivity increases, and stronger magnetoresistance and anomalous Hall effect attributed to skew scattering are observed. Ga1-xMnxAs can be controllably compensated with Te through a metal-insulator transition through which the magnetic and electrical properties vary continuously. The resistivity of insulating Ga1-xMnxAs:Te can be described by thermal activation to the mobility edge and simply-activated hopping transport. Ga1-xMnxP doped with S is insulating at all compositions but shows decreasing TC with compensation. The existence of a ferromagnetic insulating state in Ga1-xMnxAs:Te and Ga1-xMnxP:S having TCs of the same order as the uncompensated materials demonstrates that localized holes are effective at mediating ferromagnetism in ferromagnetic semiconductors through the percolation of ferromagnetic 'puddles' which at low temperatures.
Date: February 5, 2008
Creator: Scarpulla, M. A.; Stone, P. R.; Sharp, I. D.; Haller, E. E.; Dubon, O. D.; Beeman, J. W. et al.
Object Type: Article
System: The UNT Digital Library
Occupational Medicine Implications of Engineered Nanoscale Particulate Matter (open access)

Occupational Medicine Implications of Engineered Nanoscale Particulate Matter

None
Date: February 5, 2008
Creator: Kelly, Richard & Kelly, Richard J.
Object Type: Article
System: The UNT Digital Library
PERMEABILITY, SOLUBILITY, AND INTERACTION OF HYDROGEN IN POLYMERS- AN ASSESSMENT OF MATERIALS FOR HYDROGEN TRANSPORT (open access)

PERMEABILITY, SOLUBILITY, AND INTERACTION OF HYDROGEN IN POLYMERS- AN ASSESSMENT OF MATERIALS FOR HYDROGEN TRANSPORT

Fiber-reinforced polymer (FRP) piping has been identified as a leading candidate for use in a transport system for the Hydrogen Economy. Understanding the permeation and leakage of hydrogen through the candidate materials is vital to effective materials system selection or design and development of safe and efficient materials for this application. A survey of the literature showed that little data on hydrogen permeation are available and no mechanistically-based models to quantitatively predict permeation behavior have been developed. However, several qualitative trends in gaseous permeation have been identified and simple calculations have been performed to identify leakage rates for polymers of varying crystallinity. Additionally, no plausible mechanism was found for the degradation of polymeric materials in the presence of pure hydrogen. The absence of anticipated degradation is due to lack of interactions between hydrogen and FRP and very low solubility coefficients of hydrogen in polymeric materials. Recommendations are made to address research and testing needs to support successful materials development and use of FRP materials for hydrogen transport and distribution.
Date: February 5, 2008
Creator: Kane, M
Object Type: Report
System: The UNT Digital Library
Preserving Nuclear Grade Knowledge (open access)

Preserving Nuclear Grade Knowledge

When people think of the government they think of the President, or Congress, or the Internal Revenue Service (IRS), but there are thousands of people in government-related jobs doing things most don’t really notice everyday. You can find them everywhere, from the space science folks at NASA, to the Federal Bureau of Investigations (FBI) watching out for the bad guys. There are Rangers, and Social Workers, Nurses and Agricultural Managers. They are people working to keep the many facets of the USA rolling. One very diverse bunch is The Department of Energy (DOE) , a group who is expanding the ways we make and save energy to power our cars, homes, and businesses. Tucked away under the DOE is the National Nuclear Security Administration, the NNSA is an agency that maintains the safety, security, and reliability of the U.S. nuclear weapons stockpile. It works to reduce global danger from weapons of mass destruction. It provides the U.S. Navy with safe nuclear propulsion, and it responds to nuclear and radiological emergencies in the United States and abroad, and it supports efforts in science and technology*. (* DOE/NNSA/KCP website info)
Date: February 5, 2008
Creator: Lange, Bob
Object Type: Article
System: The UNT Digital Library
A Proposal for First-Ever Measurement of Coherent Neutrino-Nucleus Scattering (open access)

A Proposal for First-Ever Measurement of Coherent Neutrino-Nucleus Scattering

We propose to build and deploy a 10-kg dual-phase argon ionization detector for the detection of coherent neutrino-nucleus scattering, which is described by the reaction; {nu} + (Z,N) {yields} {nu} + (Z,N), where {nu} is the scattering neutrino, and (Z,N) is the target nucleus of atomic number Z and neutron number N. Its detection would validate central tenets of the Standard Model. We have built a gas-phase argon ionization detector to determine the feasibility of measuring the small recoil energies ({approx} 1keV) predicted from coherent neutrino scattering, and to characterize the recoil spectrum of the argon nuclei induced by scattering from medium-energy neutrons. We present calibrations made with 55-Fe, a low-energy X-ray source, and report on measurements to date of the recoil spectra from the 2-MeV LINAC Li-target neutron source at LLNL. A high signal-to-noise measurement of the recoil spectrum will not only serve as an important milestone in achieving the sensitivity necessary for measuring coherent neutrino-nucleus scattering, but will break new scientific ground on its own.
Date: February 5, 2008
Creator: Winant, C D; Bernstein, A; Foxe, M P; Hagmann, C A; Jovanovic, I; Kazkaz, K M et al.
Object Type: Report
System: The UNT Digital Library
Report on Qiagen Columns with Precipitation versus Packed Bed Technology for Trace Amounts of DNA (open access)

Report on Qiagen Columns with Precipitation versus Packed Bed Technology for Trace Amounts of DNA

The assured limit of detection (LOD), where 100% of the PCR assays are successful, for the Qiagen spin column is dramatically improved when combined with an ethanol precipitation step of the eluted sample. A detailed SOP for the ethanol precipitation was delivered as a separate report. A key finding in the precipitation work was to incubate the ethanol precipitation at -20{sup o}C overnight when concentrating low copy number samples. Combining this modified ethanol precipitation with the Qiagen spin columns, the limit of assured detection was improved by 1-2 orders of magnitude, for the aliquot and assay variables used. The lower limit of detection (defined as when at least 1 assay of 1 aliquot was positive) was only improved by approximately 1 order of magnitude. The packed bed process has the potential of a 20-fold improvement in the limit of detection compared to Qiagen plus precipitation, based on a mass balance analysis for the entire DNA concentration and purification processes. Figure ES1 shows a mass balance for all the DNA processing steps. The packed bed process minimizes losses from elution, precipitation, and pipetting (aliquoting and transferring). Figure ES1 assumes that 100 copies of DNA serve as the input sample. Efficiencies for …
Date: February 5, 2008
Creator: Wheeler, E. K.; Erler, A. M. & Seiler, A.
Object Type: Report
System: The UNT Digital Library
Research, Monitoring, and Evaluation for the Federal Columbia River Estuary Program (open access)

Research, Monitoring, and Evaluation for the Federal Columbia River Estuary Program

The purpose ofthis document is to describe research, monitoring, and evaluation (RME) for the Federal Columbia River Estuary Program. The intent of this RME effort is to provide data and information to evaluate progress toward meeting program goals and objectives and support decision-making in the Estuary Program. The goal of the Estuary Program is to understand, conserve, and restore the estuary ecosystem to improve the performance of listed salmonid populations. The Estuary Program has five general objectives, designed to fulfill the program goal, as follows. 1. Understand the primary stressors affecting ecosystem controlling factors, such as ocean conditions and invasive species. 2. Conserve and restore factors controlling ecosystem structures and processes, such as hydrodynamics and water quality. 3. Increase the quantity and quality of ecosystem structures, i.e., habitats, juvenile salmonids use during migration through the estuary. 4. Maintain the food web to benefit salmonid performance. 5. Improve salmonid performance in terms of life history diversity, foraging success, growth, and survival. The goal of estuary RME is to provide pertinent and timely research and monitoring information to planners, implementers, and managers of the Estuary Program. In conclusion, the estuary RME effort is designed to meet the research and monitoring needs of …
Date: February 5, 2008
Creator: Johnson, Gary E.; Diefenderfer, Heida L.; Ebberts, Blaine D.; Tortorici, Cathy; Yerxa, Tracey; Leary, J. et al.
Object Type: Report
System: The UNT Digital Library
Supersymmetry in Elementary Particle Physics (open access)

Supersymmetry in Elementary Particle Physics

These lectures give a general introduction to supersymmetry, emphasizing its application to models of elementary particle physics at the 100 GeV energy scale. I discuss the following topics: the construction of supersymmetric Lagrangians with scalars, fermions, and gauge bosons, the structure and mass spectrum of the Minimal Supersymmetric Standard Model (MSSM), the measurement of the parameters of the MSSM at high-energy colliders, and the solutions that the MSSM gives to the problems of electroweak symmetry breaking and dark matter.
Date: February 5, 2008
Creator: Peskin, Michael E.
Object Type: Article
System: The UNT Digital Library
Uncooled Micro-Cantilever Infrared Imager Optimization (open access)

Uncooled Micro-Cantilever Infrared Imager Optimization

We report on the development, fabrication and characterization of microcantilever based uncooled focal plane array (FPA) for infrared imaging. By combining a streamlined design of microcantilever thermal transducers with a highly efficient optical readout, we minimized the fabrication complexity while achieving a competitive level of imaging performance. The microcantilever FPAs were fabricated using a straightforward fabrication process that involved only three photolithographic steps (i.e. three masks). A designed and constructed prototype of an IR imager employed a simple optical readout based on a noncoherent low-power light source. The main figures of merit of the IR imager were found to be comparable to those of uncooled MEMS infrared detectors with substantially higher degree of fabrication complexity. In particular, the NETD and the response time of the implemented MEMS IR detector were measured to be as low as 0.5K and 6 ms, respectively. The potential of the implemented designs can also be concluded from the fact that the constructed prototype enabled IR imaging of close to room temperature objects without the use of any advanced data processing. The most unique and practically valuable feature of the implemented FPAs, however, is their scalability to high resolution formats, such as 2000 x 2000, without …
Date: February 5, 2008
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Design, Installation and Performance of the New insulator for NSTX CHI Experiments (open access)

Design, Installation and Performance of the New insulator for NSTX CHI Experiments

Coaxial Helicity Injection (CHI), a non-inductive method to initiate plasma and generate toroidal plasma current, is being investigated in the National Spherical Torus Experiment (NSTX). The center stack and outer vacuum vessel are separated by insulating gaps at the top and bottom of the slim central column so that a high voltage (up to 2 kV) can be applied between them from a pulsed power supply or a capacitor bank to initiate an arc discharge. In the presence of a suitable poloidal magnetic field, the discharge is initiated at the lower gap (the injector gap) and because of the strong toroidal field develops a helical structure resulting in substantial toroidal plasma current being driven. In NSTX, up to 390 kA of toroidal current has been generated for an injected current of 25 kA. The early investigations of CHI however frequently developed arcs across the insulator at the top of the machine (the absorber gap), which terminated the desired discharge. This arcing greatly restricted the operational space available for CHI studies. During 2002, the absorber region was modified to suppress these arcs. The new design includes a new ceramic insulator on the high field side of the absorber region with a …
Date: March 5, 2008
Creator: Mueller, D.; Chrzanowski, J.; Gates, D.; Menard, J.; Raman, R.; Jarboe, T. R. et al.
Object Type: Article
System: The UNT Digital Library
Laboratory Investigations of a Low-Swirl Injector with H2 and CH4 at Gas Turbine Conditions (open access)

Laboratory Investigations of a Low-Swirl Injector with H2 and CH4 at Gas Turbine Conditions

Laboratory experiments were conducted at gas turbine and atmospheric conditions (0.101 < P{sub 0} < 0.810 MPa, 298 < T{sub 0} < 580K, 18 < U{sub 0} < 60 m/s) to characterize the overall behaviors and emissions of the turbulent premixed flames produced by a low-swirl injector (LSI) for gas turbines. The objective was to investigate the effects of hydrogen on the combustion processes for the adaptation to gas turbines in an IGCC power plant. The experiments at high pressures and temperatures showed that the LSI can operate with 100% H{sub 2} at up to {phi} = 0.5 and has a slightly higher flashback tolerance than an idealized high-swirl design. With increasing H{sub 2} fuel concentration, the lifted LSI flame begins to shift closer to the exit and eventually attaches to the nozzle rim and assumes a different shape at 100% H{sub 2}. The STP experiments show the same phenomena. The analysis of velocity data from PIV shows that the stabilization mechanism of the LSI remains unchanged up to 60% H{sub 2}. The change in the flame position with increasing H{sub 2} concentration is attributed to the increase in the turbulent flame speed. The NO{sub x} emissions show a log …
Date: March 5, 2008
Creator: Cheng, R. K.; Littlejohn, D.; Strakey, P.A. & Sidwell, T.
Object Type: Article
System: The UNT Digital Library
Mechanism of Phosphorus Removal from Hanford Tank Sludge by Caustic Leaching (open access)

Mechanism of Phosphorus Removal from Hanford Tank Sludge by Caustic Leaching

Two experiments were conducted to explore the mechanism by which phosphorus is removed from Hanford tank sludge by caustic leaching. In the first experiment, a series of phosphate salts were treated with 3 M NaOH under conditions prototypic of the actual leaching process to be performed in the Waste Treatment and Immobilization Plant (WTP). The phosphates used were aluminum phosphate, bismuth phosphate, chromium(III) phosphate, and -tri-calcium phosphate; all of these phases have previously been determined to exist in Hanford tank sludge. The leachate solution was sampled at selected time intervals and analyzed for the specific metal ion involved (Al, Bi, Ca, or Cr) and for P (total and as phosphate). The solids remaining after completion of the caustic leaching step were analyzed to determine the reaction product. In the second experiment, the dependence of P removal from bismuth phosphate was examined as a function of the hydroxide ion concentration. It was anticipated that a plot of log[phosphate] versus log[hydroxide] would provide insight into the phosphorus-removal mechanism. This report describes the test activities outlined in Section 6.3.2.1, Preliminary Investigation of Phosphate Dissolution, in Test Plan TP-RPP-WTP-467, Rev.1. The objectives, success criteria, and test conditions of Section 6.3.2.1 are summarized here.
Date: March 5, 2008
Creator: Lumetta, Gregg J.
Object Type: Report
System: The UNT Digital Library
OFFGAS GENERATION FROM THE DISPOSITION OF SCRAP PLUTONIUM BY VITRIFICATION SIMULANT TESTS (open access)

OFFGAS GENERATION FROM THE DISPOSITION OF SCRAP PLUTONIUM BY VITRIFICATION SIMULANT TESTS

The Department of Energy Office of Environmental Management is supporting R&D for the conceptual design of the Plutonium Disposition Project at the Savannah River Site in Aiken, SC to reduce the attractiveness of plutonium scrap by fabricating a durable plutonium oxide glass form and immobilizing this form within the high-level waste glass prepared in the Defense Waste Processing Facility. A glass formulation was developed that is capable of incorporating large amounts of actinides as well as accommodating many impurities that may be associated with impure Pu feed streams. The basis for the glass formulation was derived from commercial glasses that had high lanthanide loadings. A development effort led to a Lanthanide BoroSilicate (LaBS) glass that accommodated significant quantities of actinides, tolerated impurities associated with the actinide feed streams and could be processed using established melter technologies. A Cylindrical Induction Melter (CIM) was used for vitrification of the Pu LaBS glass. Induction melting for the immobilization of americium and curium (Am/Cm) in a glass matrix was first demonstrated in 1997. The induction melting system was developed to vitrify a non-radioactive Am/Cm simulant combined with a glass frit. Most of the development of the melter itself was completed as part of that …
Date: March 5, 2008
Creator: Zamecnik, J; Patricia Toole, P; David Best, D; Timothy Jones, T; Donald02 Miller, D; Whitney Thomas, W et al.
Object Type: Article
System: The UNT Digital Library
Melting Sequence of Quarkonia (open access)

Melting Sequence of Quarkonia

In this talk I discuss what we can learn about quarkonium dissociation from lattice-potential based models, and summarize the current understanding of lattice data on quarkonium.
Date: April 5, 2008
Creator: Mocsy,A.
Object Type: Article
System: The UNT Digital Library
Molecular Surface Chemistry by Metal Single Crystals and Nanoparticles from Vacuum to High Pressure. (open access)

Molecular Surface Chemistry by Metal Single Crystals and Nanoparticles from Vacuum to High Pressure.

Model systems for studying molecular surface chemistry have evolved from single crystal surfaces at low pressure to colloidal nanoparticles at high pressure. Low pressure surface structure studies of platinum single crystals using molecular beam surface scattering and low energy electron diffraction techniques probe the unique activity of defects, steps and kinks at the surface for dissociation reactions (H-H, C-H, C-C, O{double_bond}O bonds). High-pressure investigations of platinum single crystals using sum frequency generation vibrational spectroscopy have revealed the presence and the nature of reaction intermediates. High pressure scanning tunneling microscopy of platinum single crystal surfaces showed adsorbate mobility during a catalytic reaction. Nanoparticle systems are used to determine the role of metal-oxide interfaces, site blocking and the role of surface structures in reactive surface chemistry. The size, shape and composition of nanoparticles play important roles in determining reaction activity and selectivity.
Date: April 5, 2008
Creator: Somorjai, Gabor A. & Park, Jeong Y.
Object Type: Article
System: The UNT Digital Library
Prototype Performance of Novel Muon Telescope Detector at STAR. (open access)

Prototype Performance of Novel Muon Telescope Detector at STAR.

Research on a large-area, cost-effective Muon Telescope Detector (MTD) has been carried out for RHIC and for next generation detectors at future QCD Lab. We utilize state-of-the-art multi-gap resistive plate chambers with large modules and long readout strips in detector design. The results from cosmic ray and beam test will be presented to address intrinsic timing and spatial resolution for a Long-MRPC. The prototype performance of a novel muon telescope detector at STAR will be reported, including muon identification capability, timing and spatial resolution.
Date: April 5, 2008
Creator: Ruan,L.
Object Type: Article
System: The UNT Digital Library
A systematic study of J/psi suppression in cold nuclear matter (open access)

A systematic study of J/psi suppression in cold nuclear matter

Understanding the effects of cold nuclear matter on J/psi production is a key requirement in order to interpret the J/psi suppression reported in heavy-ion collisions. Based on a Glauber model, the J/psi-nucleon inelastic cross section is determined from a statistical analysis of J/psi world data on nuclear targets. The global fit of all data gives sigmaJ/psiN = 3.4 +/- 0.2 mb, significantly smaller than previous estimates, yet the chi2 of the fit is pretty large, chi2/ndf = 1.5. A similar value, sigmaJ/psiN = 3.5 +/- 0.2 +/- 1.7 mb, is obtained when the De Florian-Sassot modifications of the nuclear parton densities are included in the analysis, although we emphasize that the present uncertainties on gluon (anti)shadowing do not allow for a precise determination of sigmaJ/psiN. Finally, the possible energy dependence of the J/psi-nucleon inelastic cross section is investigated within this framework. No significant energy dependence of the J/psi-N interaction is observed.
Date: April 5, 2008
Creator: Arleo, Francois & Tram, Vi-Nham
Object Type: Article
System: The UNT Digital Library