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Development of a readout technique for the high data rate BTeV pixel detector at Fermilab (open access)

Development of a readout technique for the high data rate BTeV pixel detector at Fermilab

The pixel detector for the BTeV experiment at Fermilab provides digitized data from approximately 22 million silicon pixel channels. Portions of the detector are six millimeters from the beam providing a substantial hit rate and high radiation dose. The pixel detector data will be employed by the lowest level trigger system for track reconstruction every beam crossing. These requirements impose a considerable constraint on the readout scheme. This paper presents a readout technique that provides the bandwidth that is adequate for high hit rates, minimizes the number of radiation hard components, and satisfies all other design constraints.
Date: November 5, 2001
Creator: al., Bradley K Hall et
System: The UNT Digital Library
Plutonium Immobilization Project - Cold Pour Phase 2 Test Results (open access)

Plutonium Immobilization Project - Cold Pour Phase 2 Test Results

The Plutonium Immobilization Project (PIP) is a program funded by the U.S. Department of Energy to develop technology for dispositioning excess weapons grade plutonium. This program introduces the ''Can-in-Canister'' (CIC) technology that immobilizes the plutonium by encapsulating it in ceramic forms (or pucks) and ultimately surrounding it with high-level waste glass to provide a deterrent to recovery. A cold (non-radioactive) test program was conducted to develop and verify the baseline design for the canister and internal hardware. Tests were conducted in two phases. Phase 1 Cold Pour Tests, conducted in 1999, were scoping tests. This paper describes the Phase 2 tests conducted in 2000 which verified the adequacy of the baseline CIC design and assured that the system would meet repository quality assurance requirements.
Date: January 5, 2001
Creator: Hamilton, L.
System: The UNT Digital Library
An Interferometric Electron Ruler With Picometer Accuracy in Gauaging Lattice Displacement. (open access)

An Interferometric Electron Ruler With Picometer Accuracy in Gauaging Lattice Displacement.

We report a novel technique to accurately measure interfacial lattice displacement by forming an electron probe close to a specimen in a manner similar to that originally proposed by Gabor to record a hologram. This method is based on the quantitative analysis of the interference pattern of shadow images in coherent electron diffraction. The approach is unique in that there are no adjustable microscope parameters, the contrast is strong even when the fault is viewed edge-on, and a large number of shadow images of the fault corresponding to different Bragg reflections can be studied simultaneously. Since it is an interferometric technique, the spatial resolution of the measurement is not limited by the wave length of the fast electrons. 1pm accuracy has been demonstrated in measuring the displacement associated stacking faults and grain boundaries in Bi-based superconductors. It is, to our knowledge, the highest that has been ever achieved in measurements of displacement vectors.
Date: August 5, 2001
Creator: Wu, L.; Zhu, Y. & Tafto, J.
System: The UNT Digital Library
The relational database aspects of Argonne's atlas control system. (open access)

The relational database aspects of Argonne's atlas control system.

None
Date: November 5, 2001
Creator: Quock, D. E. R.; Munson, F. H.; Eder, K. J. & Dean, S. L.
System: The UNT Digital Library
Photoacoustic Spectroscopy Using a Synchrotron Light Source (open access)

Photoacoustic Spectroscopy Using a Synchrotron Light Source

We have investigated the use of a synchrotron as a source for infrared photoacoustic spectroscopy. A synchrotron has an intrinsically high radiance, which is beneficial when photoacoustic spectroscopy is applied to small samples, especially at long wavelengths.
Date: February 5, 2001
Creator: Jackson, R. S.; Michaelian, K. H. & Homes, C. C.
System: The UNT Digital Library
Piston Wetting in an Optical DISI Engine: Fuel Films, Pool Fires, and Soot Generation (open access)

Piston Wetting in an Optical DISI Engine: Fuel Films, Pool Fires, and Soot Generation

Piston-wetting effects are investigated in an optical direct-injection spark-ignition (DISI) engine. Fuel spray impingement on the piston leads to the formation of fuel films, which are visualized with a laser-induced fluorescence (LIF) imaging technique. Oxygen quenching is found to reduce the fluorescence yield from liquid gasoline. Fuel films that exist during combustion of the premixed charge ignite to create piston-top pool fires. These fires are characterized using direct flame imaging. Soot produced by the pool fires is imaged using laser elastic scattering and is found to persist throughout the exhaust stroke, implying that piston-top pool fires are a likely source of engine-out particulate emissions for DISI engines.
Date: March 5, 2001
Creator: Stevens, Eric & Steeper, Richard
System: The UNT Digital Library
Phase Retrieval From Two Defocused Images by the Transport of Intensity Equation Formalism With Fast Fourier Transform. (open access)

Phase Retrieval From Two Defocused Images by the Transport of Intensity Equation Formalism With Fast Fourier Transform.

The problem of phase retrieval from intensity measurements plays an important role in many fields of physical research, e.g. optics, electron and x-ray microscopy, crystallography, diffraction tomography and others. In practice the recorded images contain information only on the intensity distribution I(x,y) = {Psi}*{Psi} = {vert_bar}A{vert_bar}{sup 2} of the imaging wave function {Psi} = A*exp(-i{var_phi}) and the phase information {var_phi}(x,y) is usually lost. In general, the phase problem can be solved either by special holographic/interferometric methods, or by non-interferometric approaches based on intensity measurements in far Fraunhofer zone or in the Fresnel zone at two adjacent planes orthogonal to the optical axis. The latter approach uses the transport-of-intensity equation (TIE) formalism, introduced originally by Teague [1] and developed later in [2]. Applications of TIE to nonmagnetic materials and magnetic inductance mapping were successfully made in [3,4]. However, this approach still needs further improvement both in mathematics and in practical solutions, since the result is very sensitive to many experimental parameters.
Date: August 5, 2001
Creator: Volkov, V. V. & Zhu, Y.
System: The UNT Digital Library
Security Implications of Typical Grid Computing Usage Scenarios (open access)

Security Implications of Typical Grid Computing Usage Scenarios

A Computational Grid is a collection of heterogeneous computers and resources spread across multiple administrative domains with the intent of providing users uniform access to these resources. There are many ways to access the resources of a Computational Grid, each with unique security requirements and implications for both the resource user and the resource provider. A comprehensive set of Grid usage scenarios are presented and analyzed with regard to security requirements such as authentication, authorization, integrity, and confidentiality. The main value of these scenarios and the associated security discussions are to provide a library of situations against which an application designer can match, thereby facilitating security-aware application use and development from the initial stages of the application design and invocation. A broader goal of these scenarios are to increase the awareness of security issues in Grid Computing.
Date: June 5, 2001
Creator: Humphrey, Marty & Thompson, Mary R.
System: The UNT Digital Library
Plutonium Immobilization Project - Can-In-Canister Hardware Development/Selection (open access)

Plutonium Immobilization Project - Can-In-Canister Hardware Development/Selection

The Plutonium Immobilization Project (PIP) is a program funded by the U.S. Department of Energy to develop technology to disposition excess weapons grade plutonium. This program introduces the ''Can-in-Canister'' (CIC) technology that immobilizes the plutonium by encapsulating it in ceramic forms (or pucks) and ultimately surrounding it with high-level waste glass to provide a deterrent to recovery. Since there are significant radiation, contamination and security concerns, the project team is developing unique technologies to remotely perform plutonium immobilization tasks. This paper covers the design, development and testing of the magazines (cylinders containing cans of ceramic pucks) and the rack that holds them in place inside the waste glass canister. Several magazine and rack concepts were evaluated to produce a design that gives the optimal balance between resistance to thermal degradation and facilitation of remote handling. This paper also reviews the effort to develop a join ted arm robot that can remotely load seven magazines into defined locations inside a stationary canister working only through the 4 inch (102 mm) diameter canister throat.
Date: January 5, 2001
Creator: Hamilton, L.
System: The UNT Digital Library
BTeV level 1 vertex trigger (open access)

BTeV level 1 vertex trigger

BTeV is a B-physics experiment that expects to begin collecting data at the C0 interaction region of the Fermilab Tevatron in the year 2006. Its primary goal is to achieve unprecedented levels of sensitivity in the study of CP violation, mixing, and rare decays in b and c quark systems. In order to realize this, it will employ a state-of-the-art first-level vertex trigger (Level 1) that will look at every beam crossing to identify detached secondary vertices that provide evidence for heavy quark decays. This talk will briefly describe the BTeV detector and trigger, focus on the software and hardware aspects of the Level 1 vertex trigger, and describe work currently being done in these areas.
Date: November 5, 2001
Creator: Wang, Michael H.L.S.
System: The UNT Digital Library
PROBABILISTIC STRUCTURAL RESPONSE OF STRUCTURE UNDER COLLAPSE LOADING (open access)

PROBABILISTIC STRUCTURAL RESPONSE OF STRUCTURE UNDER COLLAPSE LOADING

Engineers at Los Alamos National Laboratory (LANL) are currently developing the capability to provide a reliability-based structural evaluation technique for performing weapon reliability assessments. To enhance the analyst's confidence with these new methods, an integrated experiment and analysis project has been developed. The uncertainty associated with the collapse response of commercially available spherical marine float is evaluated with the aid of the non-linear explicit dynamics code DYNA3D (Whirley and Engelmann 1988) coupled with the probabilistic code NESSUS (Numerical Evaluation of Stochastic Structures Under Stress) (Thacker et al. 1998). Variations in geometric shape parameters and uncertainties in material parameters are characterized and included in the probabilistic model.
Date: January 5, 2001
Creator: PEPIN, J.; RODRIGUEZ, E. & AL, ET
System: The UNT Digital Library
ELECTRON MICROSCOPY ANALYSIS OF THE INTERMEDIATE PHASES FORMED DURING THE NUCLEATION OF YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} FILM (open access)

ELECTRON MICROSCOPY ANALYSIS OF THE INTERMEDIATE PHASES FORMED DURING THE NUCLEATION OF YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} FILM

Recently, considerable efforts have been made in growing bi-axially aligned thick YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) films on a flexible, textured metallic substrate for electrical power applications. The BaF{sub 2} post-deposition annealing process is one of the most promising methods. To understand the nucleation and growth mechanism of YBCO in this process, extended transmission electron microscopy analysis has been made. Here, we report on the evolution of Ba-Y oxy-fluoride which is pertinent to the epitaxial YBCO nucleation process on SrTiO{sub 3} (STO) substrate.
Date: August 5, 2001
Creator: Wu, L.; Zhu, Y.; Slovyov, v. F.; Wiesmann, H. J. & Suenaga, M.
System: The UNT Digital Library
62-TeV center of mass hadron collider with superbunch beams (open access)

62-TeV center of mass hadron collider with superbunch beams

The scheme of a 62-TeV center of mass p-p collider with superbunch beams at Fermilab is proposed as a practical and realistically achievable future project. It will be built in two stages, using the same tunnel, first with a 2 Tesla low field magnet collider ring and later with a 10 Tesla high field magnet collider ring. Both low and high field magnets have twin bore aperture and will be installed in the tunnel with the circumference of 87.25 km. In each bore a proton beam is accelerated, using induction cavities to increase luminosity. In the first stage they install a 7 TeV accelerator ring with operating field of 2 Tesla, based on the superferric transmission-line design. This ring will be operated at a 14-TeV center of mass collider. This will have the same energy as the LHC, but it will have 15 times higher luminosity, namely 1.5 x 10{sup 35}/cm{sup 2}/sec. The estimated synchrotron radiation is negligible with this machine. The existing Fermilab accelerator system, including the 150 GeV main injector, will be used as the injector system. Its rough cost estimation and schedule for this first stage are presented. In the second stage proton beams are accelerated, also …
Date: November 5, 2001
Creator: al., Ryuji Yamada et
System: The UNT Digital Library
Development of a next-generation regional weather research and forecast model. (open access)

Development of a next-generation regional weather research and forecast model.

The Weather Research and Forecast (WRF) project is a multi-institutional effort to develop an advanced mesoscale forecast and data assimilation system that is accurate, efficient, and scalable across a range of scales and over a host of computer platforms. The first release, WRF 1.0, was November 30, 2000, with operational deployment targeted for the 2004-05 time frame. This paper provides an overview of the project and current status of the WRF development effort in the areas of numerics and physics, software and data architecture, and single-source parallelism and performance portability.
Date: February 5, 2001
Creator: Michalakes, J.; Chen, S.; Dudhia, J.; Hart, L.; Klemp, J.; Middlecoff, J. et al.
System: The UNT Digital Library
Computational Design Studies for an Ion Extraction System for a ''volume-type'' ECR Ion Source (open access)

Computational Design Studies for an Ion Extraction System for a ''volume-type'' ECR Ion Source

Numerical studies have been performed for optimally extracting high-intensity, space-charged-limited multi-charged ion beams from an all-permanent-magnet, ''volume-type'' ECR ion source, equipped with a three-electrode extraction system. These studies clearly demonstrate the importance of being able to adjust the extraction gap in order to ensure high quality, minimum divergence (highly transportable) ion beams. Optimum extraction conditions are reached whenever the plasma meniscus has an optimum curvature for a given current density. Optimum perveance (optimum current) values are found to closely agree with those derived from elementary analytical theory for extraction of space-charge-dominated beams. Details of the electrode system design as well as angular divergence and RMS emittance versus extraction parameter data (e.g., perveance and extraction gap) are provided for ion beams of varying charge-state and mass, extracted under the influence of a mirror-geometry plasma confinement magnetic field.
Date: November 5, 2001
Creator: Zaim, H.
System: The UNT Digital Library
Thermal and mechanical effects of quenches on Nb{sub 3}Sn high field hadron collider magnets (open access)

Thermal and mechanical effects of quenches on Nb{sub 3}Sn high field hadron collider magnets

Thermal and its resulting mechanical stress due to quenches inside short and long epoxy impregnated Nb{sub 3}Sn high field magnets are studied with a quench simulation program, Kuench, and ANSYS program. For the protection of a long high field magnet, we have to use heaters to dump the stored energy uniformly inside the magnet, after detection of a spontaneous quench. The time delay of starting a forced quench with heaters, is estimated using ANSYS. Using this information, the thermal distribution in two-dimensional magnet cross section is studied. First a one meter model magnet with a dump resistor is used to estimate the effects and then a 10 meter long magnet is studied. The two-dimensional temperature distributions in the magnet cross sections are recorded every 5 ms, and visually displayed. With this visual animation displays we can understand intuitively the thermal and quench propagation in 2-dimensional field. The quenching cables get heated locally much more than the surrounding material and non-quenching conductor cables. With a one meter magnet with a dump resistor of 30 m{Omega}, typically only the quench starting cables and its neighbor cables get heated up to 100 K without significant effects from the heaters. With a10 meter magnet, …
Date: November 5, 2001
Creator: al., Ryuji Yamada et
System: The UNT Digital Library
Effusive-flow characterization of arbitrary size and geometry target/vapor transport systems: radioactive ion beam applications (open access)

Effusive-flow characterization of arbitrary size and geometry target/vapor transport systems: radioactive ion beam applications

The principal factors that severely limit intensities of short-lived radioactive ion beams produced by the Isotope Separator On-Line (ISOL) technique are time delays due to diffusion of radioactive species from solid or liquid target materials and their effusive-flow transport to the ion source. Although diffusion times can be reduced by proper design of short diffusion length, highly refractory targets, effusive-flow times are more difficult to assess. After diffusion from the target material, the species must travel through the target material and vapor transport system to the ion source. The time required for effusive-flow transport to the ion source depends on the conduction path, chemical reactions between the species and target material and materials of construction as well as the physical size and geometry of the transport system. We have developed a fast-valve (1 ms closing time) for introducing gaseous or vapor-state species into the target/vapor transport/ion source/system th at permits measurement of effusive-flow times for any gaseous or vaporous species (chemically active or chemically inactive) through any vapor transport system, independent of size and geometry. Characteristic times are determined from the exponential decay of the momentum analyzed ion beam intensity for the species.during effusive-flow through the vapor transport system under …
Date: November 5, 2001
Creator: Bilheux, J.-C.
System: The UNT Digital Library
Optimization of the Ion-Cut Process in Si and SiC (open access)

Optimization of the Ion-Cut Process in Si and SiC

None
Date: January 5, 2001
Creator: Holland, O.W.
System: The UNT Digital Library
Maintaining data quality in an environmental testing laboratory (open access)

Maintaining data quality in an environmental testing laboratory

In today's competitive and highly litigious world, it is critical that any laboratory generating data for the environmental and allied industries have a world-class Quality Assurance Program. This Plan must conform to the requirements of every agency and client with whom the lab does business. The goal of such a program is data defensibility; i.e., data validity. Data (usually qualitative analyte [compound or element] identifications and quantitative numerical results) are the end results of nearly all analytical laboratory processes, and the source of revenue. Clients pay for results. The clients expect the results to be accurate, precise, and repeatable. If their data has to go to court, the laboratory will be called upon to defend the accuracy and precision of their work. Without a strong QA program, this will be impossible. The potential implications and repercussions of non-defensible lab data are far-reaching and very costly in terms of loss of future revenues and in legal judgments.
Date: March 5, 2001
Creator: Cohen, Roy J.
System: The UNT Digital Library
Performance and cost of particle air filtration technologies (open access)

Performance and cost of particle air filtration technologies

None
Date: May 5, 2001
Creator: Fisk, William J. & Faulkner, David
System: The UNT Digital Library
Analysis of Geomechanical Behavior for the Drift Scale Test (open access)

Analysis of Geomechanical Behavior for the Drift Scale Test

The Drift Scale Test (DST) now underway at Yucca Mountain has been simulated using a Drift Scale Distinct Element (DSDE) model. Simulated deformations show good agreement with field deformation measurements. Results indicate most fracture deformation is located above the crown of the Heated Drift. This work is part of the model validation effort for the DSDE model, which is used to assess thermal-mechanical effects on the hydrology of the rock mass surrounding a potential repository.
Date: March 5, 2001
Creator: Blair, S.C.; Carlson, S.R. & Wagoner, J.L.
System: The UNT Digital Library
10 (micro)m and 5 (micro)m Pinhole-Assisted Point-Projection Backlit Imaging for NIF (open access)

10 (micro)m and 5 (micro)m Pinhole-Assisted Point-Projection Backlit Imaging for NIF

Pinhole-assisted point-projection backlighting with 10{micro}m and 5 {micro}m pinholes placed a small distance of order 1 mm away from the backlighter produces images with large field of view and high resolution. Pinholes placed closely to high-power backlighter sources can vaporize and close due to x-ray driven ablation, thereby limiting the usefulness of this method. A study of streaked 1-D backlit imaging of 25 {micro}m W wires using the OMEGA laser is presented. The pinhole closure timescale for 10 {micro}m pinholes placed 0.45 mm and 1 mm distant from the backlighter is 1.3 ns and 2.2 ns, respectively. Similar timescales for 5 {micro}m pinholes is also presented. Successful wire imaging prior to pinhole closure is clearly demonstrated.
Date: June 5, 2001
Creator: Bullock, A. B.; Landen, O. L. & Bradley, D. K.
System: The UNT Digital Library
EXAFS and activity studies of the poisoning effect on Cl on Pt/Al{sub 2}O{sub 3} catalysts during oxidation reactions. (open access)

EXAFS and activity studies of the poisoning effect on Cl on Pt/Al{sub 2}O{sub 3} catalysts during oxidation reactions.

The effect of Cl on the activity of Pt/Al{sub 2}O{sub 3} catalysts for methane oxidation has been studied by H{sub 2} and CO chemisorption, O{sub 2} isotopic exchange, kinetic studies and EXAFS spectroscopy. Catalysts containing 1.5% pt/Al{sub 2}O{sub 3} were prepared by incipient wetness from H{sub 2}PtCl{sub 6} and Pt(NH{sub 3}){sub 4}(NO{sub 3}){sub 2} precursors. Both reduced catalysts have similar dispersion (0.8) as determined by H{sub 2} chemisorption. At low methane concentration (0.3 vol.% CH{sub 4}, 16 vol.% O{sub 2}) the Cl-free catalyst was about 20 times more active during complete methane oxidation than the Cl-containing catalyst. Both CO chemisorption and oxygen exchange were observed on the Cl-free catalyst, whereas they were not detected on the Cl-containing catalyst. On the Cl-free catalyst, only Pt-Pt and Pt-O bonds were detected from the EXAFS results, while on the Cl-containing catalyst additional Pt-Cl bonds were present. The effect of chlorine on activity strongly depended on the reactant concentration. Exposure of the Cl-free catalyst to higher concentrations of methane (3 vol.% CH{sub 4}) reduced the activity to a level similar to that of the Cl-containing catalyst. Addition of HCl to the Cl-free catalyst rendered the activity identical to the catalyst prepared from Cl-containing precursors. …
Date: April 5, 2001
Creator: Gracia, F.; Wolf, E. E.; Miller, J. T. & Kropf, A. J.
System: The UNT Digital Library
Strange Goings on in Quark Matter. (open access)

Strange Goings on in Quark Matter.

We review recent work on how the superfluid state of three flavor quark matter is affected by non-zero quark masses and chemical potentials. The study of hadronic matter at high baryon density has recently attracted a lot of interest. At zero baryon density chiral symmetry is broken by a quark-anti-quark condensate. At high density condensation in the quark-anti-quark channel is suppressed. Instead, attractive interactions in the color anti-symmetric quark-quark channel favor the formation of diquark condensates. As a consequence, cold dense quark matter is expected to be a color superconductor. The symmetry breaking pattern depends on the density, the number of quark flavors, and their masses. A particularly symmetric phase is the color-flavor-locked (CFL) phase of three flavor quark matter. This phase is believed to be the true ground state of ordinary matter at very large density.
Date: June 5, 2001
Creator: Schafer, T.
System: The UNT Digital Library