Optical Absorption, Stability and Structure of NpO2+ Complexeswith Dicarboxylic Acids (open access)

Optical Absorption, Stability and Structure of NpO2+ Complexeswith Dicarboxylic Acids

Complexation of NpO2+ with oxalic acid (OX),2,2'-oxydiacetic acid (ODA), 2,2'-iminodiacetic acid (IDA) and 2,2'-thiodiacetic acid (TDA), has been studied using spectrophotometry in1 M NaClO4. Both the position and the intensity of the absorption band of NpO2+ at 980 nm are affected by the formation of NpO2+/dicarboxylate complexes, providing useful information on the complexation strength, the coordination mode and the structure of the complexes.
Date: January 4, 2006
Creator: Tian, Guoxin & Rao, Linfeng
Object Type: Article
System: The UNT Digital Library
Using Radar, Lidar, and Radiometer measurements to Classify Cloud Type and Study Middle-Level Cloud Properties (open access)

Using Radar, Lidar, and Radiometer measurements to Classify Cloud Type and Study Middle-Level Cloud Properties

The project is concerned with the characterization of cloud macrophysical and microphysical properties by combining radar, lidar, and radiometer measurements available from the U.S. Department of Energy's ARM Climate Research Facility (ACRF). To facilitate the production of integrated cloud product by applying different algorithms to the ARM data streams, an advanced cloud classification algorithm was developed to classified clouds into eight types at the SGP site based on ground-based active and passive measurements. Cloud type then can be used as a guidance to select an optimal retrieval algorithm for cloud microphysical property retrieval. The ultimate goal of the effort is to develop an operational cloud classification algorithm for ARM data streams. The vision 1 IDL code of the cloud classification algorithm based on the SGP ACRF site observations was delivered to the ARM cloud translator during 2004 ARM science team meeting. Another goal of the project is to study midlevel clouds, especially mixed-phase clouds, by developing new retrieval algorithms using integrated observations at the ACRF sites. Mixed-phase clouds play a particular role in the Arctic climate system. A multiple remote sensor based algorithm, which can provide ice water content and effective size profiles, liquid water path, and layer-mean effective radius …
Date: January 4, 2006
Creator: Wang, Zhien
Object Type: Report
System: The UNT Digital Library
Assessing the Effects of Radiation Damage on Ni-base Alloys for the Prometheus Space Reactor System (open access)

Assessing the Effects of Radiation Damage on Ni-base Alloys for the Prometheus Space Reactor System

Ni-base alloys were considered for the Prometheus space reactor pressure vessel with operational parameters of {approx}900 K for 15 years and fluences up to 160 x 10{sup 20} n/cm{sup 2} (E > 0.1 MeV). This paper reviews the effects of irradiation on the behavior of Ni-base alloys and shows that radiation-induced swelling and creep are minor considerations compared to significant embrittlement with neutron exposure. While the mechanism responsible for radiation-induced embrittlement is not fully understood, it is likely a combination of helium embrittlement and solute segregation that can be highly dependent on the alloy composition and exposure conditions. Transmutation calculations show that detrimental helium levels would be expected at the end of life for the inner safety rod vessel (thimble) and possibly the outer pressure vessel, primarily from high energy (E > 1 MeV) n,{alpha} reactions with {sup 58}Ni. Helium from {sup 10}B is significant only for the outer vessel due to the proximity of the outer vessel to the BeO control elements. Recommendations for further assessments of the material behavior and methods to minimize the effects of radiation damage through alloy design are provided.
Date: April 4, 2006
Creator: Angeliu, T.; Ward, J. & Witter, J.
Object Type: Report
System: The UNT Digital Library
Predicting Coupled Ocean-Atmosphere Modes with a Climate Modeling Hierarchy -- Final Report (open access)

Predicting Coupled Ocean-Atmosphere Modes with a Climate Modeling Hierarchy -- Final Report

The goal of the project was to determine midlatitude climate predictability associated with tropical-extratropical interactions on interannual-to-interdecadal time scales. Our strategy was to develop and test a hierarchy of climate models, bringing together large GCM-based climate models with simple fluid-dynamical coupled ocean-ice-atmosphere models, through the use of advanced probabilistic network (PN) models. PN models were used to develop a new diagnostic methodology for analyzing coupled ocean-atmosphere interactions in large climate simulations made with the NCAR Parallel Climate Model (PCM), and to make these tools user-friendly and available to other researchers. We focused on interactions between the tropics and extratropics through atmospheric teleconnections (the Hadley cell, Rossby waves and nonlinear circulation regimes) over both the North Atlantic and North Pacific, and the ocean’s thermohaline circulation (THC) in the Atlantic. We tested the hypothesis that variations in the strength of the THC alter sea surface temperatures in the tropical Atlantic, and that the latter influence the atmosphere in high latitudes through an atmospheric teleconnection, feeding back onto the THC. The PN model framework was used to mediate between the understanding gained with simplified primitive equations models and multi-century simulations made with the PCM. The project team is interdisciplinary and built on an …
Date: August 4, 2006
Creator: Ghil, Michael; Robertson, Andrew W.; Kravtsov, Sergey & Smyth, Padhraic
Object Type: Report
System: The UNT Digital Library
A QUICK KEY TO THE SUBFAMILIES AND GENERA OF ANTS OF THE SAVANNAH RIVER SITE, AIKEN, SC (open access)

A QUICK KEY TO THE SUBFAMILIES AND GENERA OF ANTS OF THE SAVANNAH RIVER SITE, AIKEN, SC

This taxonomic key was devised to support development of a Rapid Bioassessment Protocol using ants at the Savannah River Site. The emphasis is on ''rapid'' and, because the available keys contained a large number of genera not known to occur at the Savannah River Site, we found that the available keys were unwieldy. Because these keys contained more genera than we would likely encounter and because this larger number of genera required both more couplets in the key and often required examination of characters that are difficult to assess without higher magnifications (60X or higher) more time was required to process samples. In developing this set of keys I recognize that the character sets used may lead to some errors but I believe that the error rate will be small and, for the purpose of rapid bioassessment, this error rate will be acceptable provided that overall sample sizes are adequate. Oliver and Beattie (1996a, 1996b) found that for rapid assessment of biodiversity the same results were found when identifications were done to morphospecies by people with minimal expertise as when the same data sets were identified by subject matter experts. Basset et al. (2004) concluded that it was not as …
Date: October 4, 2006
Creator: Martin, D
Object Type: Report
System: The UNT Digital Library
Summary Of Identification Of Rrgulatory Acceptability Of Enhanced Attenuation Categories (open access)

Summary Of Identification Of Rrgulatory Acceptability Of Enhanced Attenuation Categories

Chlorinated solvents once introduced to the subsurface are a persistent contaminant. Though many types of active treatments have been developed and deployed to treat contaminated sites, most sites will ultimately incorporate the use of passive treatments into the remediation process. A process favored by many is the use of Monitored Natural Attenuation that relies on the natural attenuation processes occurring within the system to remediate the contaminants. However, it is likely there will be instances where the natural attenuation processes will be insufficient to reduce the level of contamination to acceptable levels in an acceptable span of time. Rather than redeploying source treatments, the Department of Energy along with the Interstate Technology and Regulatory Council (ITRC) are developing the concept of Enhanced Attenuation (EA). An enhancement is any type of intervention that might be implemented in a source-plume system that increases the magnitude of attenuation by natural processes beyond that which occurs without intervention. Enhanced Attenuation is the result of applying an enhancement or intervention technique that will sustainably manipulate a natural attenuation process leading to an increased reduction in mass flux of contaminants. Efforts are moving forward along several fronts in developing this concept. This effort is a follow-on …
Date: January 4, 2006
Creator: Vangelas, K
Object Type: Report
System: The UNT Digital Library
Brief History of Ffag Accelerators. (open access)

Brief History of Ffag Accelerators.

Colleagues of mine have asked me few times why we have today so much interest in Fixed-Field Alternating-Gradient (FFAG) accelerators when these were invented a long time ago, and have always been ignored since then. I try here to give a reply with a short history of FFAG accelerators, at least as I know it. I take also the opportunity to clarify few definitions.
Date: December 4, 2006
Creator: Ruggiero, A.
Object Type: Article
System: The UNT Digital Library
X-ray Pulse Length Characterization using the Surface Magneto Optic Kerr Effect (open access)

X-ray Pulse Length Characterization using the Surface Magneto Optic Kerr Effect

It will be challenging to measure the temporal profile of the hard X-ray SASE beam independently from the electron beam in the LCLS and other 4th generation light sources. A fast interaction mechanism is needed that can be probed by an ultrafast laser pulse in a pump-probe experiment. It is proposed to exploit the rotation in polarization of light reflected from a thin magnetized film, known as the surface magneto optic Kerr effect (SMOKE), to witness the absorption of the x-ray pulse in the thin film. The change in spin orbit coupling induced by the x-ray pulse occurs on the subfemtosecond time scale and changes the polarization of the probe beam. The limitation to the technique lies with the bandwidth of the probe laser pulse and how short the optical pulse can be made. The SMOKE mechanism will be described and the choices of materials for use with 1.5 {angstrom} x-rays. A schematic description of the pump-probe geometry for x-ray diagnosis is also described.
Date: October 4, 2006
Creator: Krejcik, P.
Object Type: Article
System: The UNT Digital Library
Improving the Raster Scanning Methods used with X-ray Fluorescence to See the Ancient Greek Text of Archimedes (SULI Paper) (open access)

Improving the Raster Scanning Methods used with X-ray Fluorescence to See the Ancient Greek Text of Archimedes (SULI Paper)

X-ray fluorescence is being used to detect the ancient Greek copy of Archimedes work. The copy of Archimedes text was erased with a weak acid and written over to make a prayer book in the Middle Ages. The ancient parchment, made of goat skin, has on it some of Archimedes most valuable writings. The ink in the text contains iron which will fluoresce under x-ray radiation. My research project deals with the scanning and imaging process. The palimpsest is put in a stage that moves in a raster format. As the beam hits the parchment, a germanium detector detects the iron atoms and discriminates against other elements. Since the computer scans in both forwards and backwards directions, it is imperative that each row of data lines up exactly on top of the next row. There are several parameters to consider when scanning the parchment. These parameters include: speed, count time, shutter time, x-number of points, and acceleration. Formulas were made to relate these parameters together. During the actual beam time of this project, the scanning was very slow going; it took 30 hours to scan 1/2 of a page. Using the formulas, the scientists doubled distance and speed to scan …
Date: January 4, 2006
Creator: Griffin, Isabella B. & /Norfolk State U. /SLAC, SSRL
Object Type: Report
System: The UNT Digital Library
Annual Report Electrochemical Machining of Access Holes (open access)

Annual Report Electrochemical Machining of Access Holes

We report the advances made in electrochemical machining of access holes through sheet metal during FY2005. The cutting tool underwent a major engineering re-design to accommodate an oblong cut with parallel sides (1.5'' spacing) on a surface of arbitrary curvature. The solid cathode was replaced by an array of separately movable steel pins, allowing the tool to conform to the surface shape of the work piece prior to beginning cutting. Preliminary cuts through a hardened steel drum (0.04 inch thickness) were successfully completed at a low current (50A) but the current efficiency of the cutting process was poor (<30%). Efficiency was improved to 75% and the cutting time reduced to 8 minutes in heated electrolyte at 100 A and 4.5 V. This work led to improvements in process simplicity and ease of operation: (1) continuous movement of the cathode towards the work piece was eliminated in favor of a fixed cathode; (2) the surfaces of the cutting pins do not require insulation; (3) a spider support for the tool provides for rapid positioning of the cutting tool; (4) negative electrolyte pressure minimized leakage into the drum following breakthrough. We found no reactivity of various HE's with alternative candidate ECM electrolytes.
Date: January 4, 2006
Creator: Cooper, J. F.; Evans, M. & Whipple, R.
Object Type: Report
System: The UNT Digital Library
Shape Determination for Deformed Cavities (open access)

Shape Determination for Deformed Cavities

A realistic superconducting RF cavity has its shape deformed comparing to its designed shape due to the loose tolerance in the fabrication process and the frequency tuning for its accelerating mode. A PDE-constrained optimization problem is proposed to determine the deformation of the cavity. A reduce space method is used to solve the PDE-constrained optimization problem where design sensitivities were computed using a continuous adjoint approach. A proof-of-concept example is given in which the deformation parameters of a single cavity-cell with two different types of deformation were computed.
Date: October 4, 2006
Creator: Lee, Lie-Quan; Akcelik, Volkan; Chen, Sheng; Ge, Lixin; Li, Zenghai; Ng, Cho et al.
Object Type: Report
System: The UNT Digital Library
Effect of Substrate Surface Defects and Te Dopant Concentration on Crystalline Quality and Electrical Characteristics of AlGaAsSb Epitaxial Layers (open access)

Effect of Substrate Surface Defects and Te Dopant Concentration on Crystalline Quality and Electrical Characteristics of AlGaAsSb Epitaxial Layers

The influence of GaSb substrate surface defects such as native oxides on the crystalline quality of epitaxial layers was investigated using transmission electron microscopy (TEM). Cross sectional TEM imaging showed that there are discrete defects at the GaSb-substrate/epilayer interface. Secondary ion mass spectroscopy (SIMS) results revealed high oxygen concentration at the interface, indicating that the defects are likely oxides and presumed to be native oxides since other impurities were not detected. High resolution TEM micrographs showed that the subsequent growth of the epilayer continues beyond the defects without any additional defect generation or propagation. Tellurium doped AlGaAsSb epitaxial layers were grown lattice-matched on GaSb substrates and lattice-mismatched on semi-insulating GaAs substrates by organometallic vapor phase epitaxy. Secondary ion mass spectroscopy and Hall data showed that the ratio of carrier concentration to Te concentration decreases significantly when the carrier concentration increases from 2.5 x 10{sup 17} cm{sup -3} to 6.5 x 10{sup 17} cm{sup -3}. TEM imaging showed that the material with heavily doped Te generates a high density (about 10{sup 8} cm{sup 2}) of planar defects (stacking fault) located on (111) planes. Most of the Te-related defects originate at the GaSb buffer layer/AlGaAsSb epilayer interface. In addition, discrete precipitates were …
Date: January 4, 2006
Creator: Ehsani, H; Lewis, N; Nichols, G; Danielson, L; Dashiell, M; Shellenbarger, Z et al.
Object Type: Article
System: The UNT Digital Library
Measurement of Gravitational Lens Time Delays with LSST (SULI Paper) (open access)

Measurement of Gravitational Lens Time Delays with LSST (SULI Paper)

The proposed Large Synoptic Survey Telescope will be the first to explore multiple dark energy probes simultaneously, including baryon acoustic oscillations, weak lensing, and strong gravitational lensing. The large data sample, covering the entire visible sky every few nights, will allow an unprecedented survey of deep supernova sources and their lensed images. The latter have not yet been observed. Notably, LSST will measure the time delays between different strong-lensed images of the same supernova. This will provide a unique probe of dark matter, dark energy, and the expansion rate of the Universe. By simulating LSST observations under realistic conditions, we determined the time delay precision of multiple images from a representative strong-lensed Type Ia supernova. The output of the simulation was a set of light curves according to field and filter, which were subsequently analyzed to determine the experimental time delays. We find that a time delay precision of better then 10% can be achieved under suitable conditions. Firstly, a minimum observed peak-magnitude of 22 is required for the lensed image, corresponding to an intrinsic source magnitude of about 24. The number of such supernova sources expected for LSST is under investigation, but it could amount to several thousand. Secondly, …
Date: January 4, 2006
Creator: Kirkby, Lowry Anna & /SLAC, /Oxford U.
Object Type: Report
System: The UNT Digital Library
Localized PEPII Storage Ring Optics Measurements (SULI paper) (open access)

Localized PEPII Storage Ring Optics Measurements (SULI paper)

The current technique employed to determine the parameters which specify the betatron oscillation in the PEPII ring at SLAC is a global procedure in that the data from each BPM (Beam Position Monitor) is weighted equally. However for more accurate interaction point (IP) measurements it would be beneficial to weight the data from the BPMs closest to the IP much more heavily. Researchers are thus considering the possibility of developing a technique to determine the oscillation parameters near the IP using as few BPMs as possible. In this paper, allowing BPM gains and cross coupling, we show analytically that given data from N BPMs there remain 6N + 2 degrees of freedom in the matrices M{sub A,A}, M{sub B,A}, ..., M{sub N,N-1} unspecified by the observable data alone. From this we demonstrate that data from at least 3 BPMs is required to completely specify the system when the transfer maps between BPMs are assumed known, and that 4 BPMs may be more suitable.
Date: January 4, 2006
Creator: Landy, Jonthan & /SLAC, /Caltech
Object Type: Report
System: The UNT Digital Library
Configuration Studies and Recommendations for the ILC DampingRings (open access)

Configuration Studies and Recommendations for the ILC DampingRings

We describe the results of studies comparing differentoptions for the baseline configuration of the ILC damping rings. Theprincipal configuration decisions apply to the circumference, beamenergy, lattice type, and technology options for key components,including the injection/extraction kickers and the damping wigglers. Toarrive at our recommended configuration, we performed detailed studies ofa range of lattices representing a variety of different configurationoptions; these lattices are described in Chapter 2. The results of thevarious studies are reported in chapters covering issues of beamdynamics, technical subsystems, costs, and commissioning, reliability andupgradeability. Our detailed recommendations for the baselineconfiguration are given in Chapter 7, where we also outline furtherresearch and development that is needed before a machine using ourrecommended configuration can be built and operated successfully. In thesame chapter, we suggest possible alternatives to the baselineconfiguration.
Date: February 4, 2006
Creator: Wolski, Andrzej; Gao, Jie & Guiducci, Susanna
Object Type: Report
System: The UNT Digital Library
Time-resolved Soft X-Ray Imaging (SXRI) diagnostic for use at the NIF and OMEGA lasers (open access)

Time-resolved Soft X-Ray Imaging (SXRI) diagnostic for use at the NIF and OMEGA lasers

The soft x-ray imager (SXRI) built for the first experiments at the National Ignition Facility (NIF) has four soft x-ray channels and one hard x-ray channel. The SXRI is a snout that mounts to a four strip gated imager. This produces four soft x-ray images per strip, which can be separated in time by {approx}60psec. Each soft x-ray channel consists of a mirror plus a filter. The diagnostic was used to study x-ray burnthrough of hot hohlraum targets at the NIF and OMEGA lasers. The SXRI snout design and issues involved in selecting the desired soft x-ray channels are discussed.
Date: May 4, 2006
Creator: Schneider, M; Holder, J; James, D; Bruns, H; Celeste, J; Compton, S et al.
Object Type: Article
System: The UNT Digital Library
Final Technical Report - A Combined Synthetic, Spectroscopic, and Theoretical Approach to the Rational Design of Photophysical and Photochemical Properties of Dendrimers (open access)

Final Technical Report - A Combined Synthetic, Spectroscopic, and Theoretical Approach to the Rational Design of Photophysical and Photochemical Properties of Dendrimers

We summarize progress in the DOE project, "A Combined Synthetic, Spectroscopic, and Theoretical Approach to the Rational Design of Photophysical and Photochemical Properties of Dendrimers."
Date: October 4, 2006
Creator: Bardeen, C. J.; Martinez, T. J. & Moore, J. S.
Object Type: Report
System: The UNT Digital Library
Distinguishing Monosaccharide Stereo- and Structural Isomers with ToF-SIMS and Multivariate Statistical Analysis (open access)

Distinguishing Monosaccharide Stereo- and Structural Isomers with ToF-SIMS and Multivariate Statistical Analysis

Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) is utilized to examine the mass spectra and fragmentation patterns of seven isomeric monosaccharides. Multivariate statistical analysis techniques, including principal component analysis (PCA), allow discrimination of the extremely similar mass spectra of stereoisomers. Furthermore, PCA identifies those fragment peaks which vary significantly between spectra. Heavy isotope studies confirm that these peaks are indeed sugar fragments, allow identification of the fragments, and provide clues to the fragmentation pathways. Excellent reproducibility is shown by multiple experiments performed over time and on separate samples. This study demonstrates the combined selectivity and discrimination power of ToF-SIMS and PCA, and suggests new applications of the technique including differentiation of subtle chemical changes in biological samples that may provide insights into cellular processes, disease progress, and disease diagnosis.
Date: May 4, 2006
Creator: Berman, E. F.; Kulp, K. S.; Knize, M. G.; Wu, L.; Nelson, E. J.; Nelson, D. O. et al.
Object Type: Article
System: The UNT Digital Library
Quantifying And Predicting Wood Quality Of Loblolly And Slash Pine Under Intensive Forest Management Final Technical Report (open access)

Quantifying And Predicting Wood Quality Of Loblolly And Slash Pine Under Intensive Forest Management Final Technical Report

The forest industry will increasingly rely on fast-growing intensively managed southern pine plantations to furnish wood and fiber. Intensive silvicultural practices, including competition control, stand density control, fertilization, and genetic improvement are yielding tremendous gains in the quantity of wood production from commercial forest land. How these technologies affect wood properties was heretofore unknown, although there is concern about the suitability of fast-grown wood for traditional forest products. A four year study was undertaken to examine the effects of these intensive practices on the properties of loblolly and slash pine wood by applying a common sampling method over 10 existing field experiments. Early weed control gets young pines off to a rapid start, often with dramatically increased growth rates. This response is all in juvenile wood however, which is low in density and strength. Similar results are found with early Nitrogen fertilization at the time of planting. These treatments increase the proportion of juvenile wood in the tree. Later, mid-rotation fertilization with Nitrogen and Phosphorus can have long term (4-8 year) growth gains. Slight reductions in wood density are short-lived (1-2 years) and occur while the tree is producing dense, stiff mature wood. Impacts of mid-rotation fertilization on wood properties …
Date: May 4, 2006
Creator: Daniels, Richard F. & III, Alexander Clark
Object Type: Report
System: The UNT Digital Library
The Heat Loss Analysis and Commissioning of a Commercial Helium Dewar (SULI paper) (open access)

The Heat Loss Analysis and Commissioning of a Commercial Helium Dewar (SULI paper)

A low temperature cryostat suitable for many different experiments will be commissioned at the cryogenic test facility at SLAC. The scope of the project is to make commission a commercial Helium dewar. The building of the top flange will be followed from its design phase through to its finished assembly. In addition, diagnostic tools such as thermometry, level detector, pressure gauge, transfer lines for He and N2, vent lines with relief valves for He and N2 will be incorporated. Instrumentation to read and plot this data will also be included. Once the cryostat is assembled, we will cool down the cryostat to measure its performance. A typical consumption rate of Helium will be measured and from this, the overall heat leak to the dewar will be calculated. A processing instrumentation diagram (PID) of the dewar system was created with SolidEdge and was later approved and published as an official SLAC document. The plots comparing the liquid level changes of the 36 inch probe with the time and the heat loss as a function of time proved to be a valid indication that the data was interpreted and recorded correctly and that the dewar was put together successfully.
Date: January 4, 2006
Creator: Bellamy, Marcus & /SLAC, /New Mexico U.
Object Type: Report
System: The UNT Digital Library
Determinations of the Matrix Element V(Ub) From Inclusive Semileptonic B Decays With Reduced Model Dependency (open access)

Determinations of the Matrix Element V(Ub) From Inclusive Semileptonic B Decays With Reduced Model Dependency

None
Date: April 4, 2006
Creator: Hill, Edward J. & /UC, San Diego
Object Type: Report
System: The UNT Digital Library
Extended Source Gamma-Ray Emission from WIMP Annihilation in the Sagittarius Dwarf Elliptical Galaxy (SULI paper) (open access)

Extended Source Gamma-Ray Emission from WIMP Annihilation in the Sagittarius Dwarf Elliptical Galaxy (SULI paper)

The proximity of the dark matter dominated Sagittarius Dwarf Elliptical Galaxy (position (l,b) = 5.6{sup o}, -14{sup o}) allows it to act as an ideal laboratory for the exploration of extended gamma-ray emission from Weakly Interacting Massive Particle (WIMP) annihilation processes in a dark matter-dominated system. Since the matter in our universe is predominantly dark, exploring such processes as WIMP annihilation will lead to a better understanding of cosmology. In order to study this gamma-ray emission, a model for the diffuse background gamma-radiation in the dwarf galaxy's region is extracted from the Energetic Gamma Ray Experiment Telescope (EGRET) data. After validating this model and comparing it to the EGRET diffuse model, the background model is added to effective bleeding-contamination from external point sources and multiple models for the signal-above-background emission. Various models of this emission are tested: (a) no source located in region, (b) unidentified point source 3EG J1847-3219 from the Third EGRET Catalog responsible for the emission and (c) extended emission resulting from WIMP annihilation responsible for the signal above background. These models are created through the employment of Monte Carlo simulation methods, utilizing the response functions of the EGRET instrument to simulate the point spread function, energy dispersion …
Date: January 4, 2006
Creator: Vasu-Devan, Vidya & /SLAC, /Columbia U.
Object Type: Report
System: The UNT Digital Library
Hardware Testing of the BaBar Drift Chamber Electronics Upgrade (SULI paper) (open access)

Hardware Testing of the BaBar Drift Chamber Electronics Upgrade (SULI paper)

The BaBar drift chamber provides position, timing, and dE/dx measurements for charged decay products of the {Upsilon}(4S) resonance at 10.58 GeV. Increasing data collection rates stemming from higher PEP II luminosities and background have highlighted dead time problems in the drift chamber's data acquisition system. A proposed upgrade, called Phase II, aims to solve the problem with the introduction of rewritable, higher-memory firmware in the DAQ front-end electronics that lowers dataflow through the system. After fabrication, the new electronics components were tested to ensure proper function and reliability before installation in the detector. Some tests checked for successful operation of individual components, while others operated entire sections of the upgraded system in a mockup drift chamber environment. This paper explains the testing process and presents results regarding performance of the upgrade electronics.
Date: January 4, 2006
Creator: Littlejohn, Bryce; Chu, Yiwen & Wiik, Liv
Object Type: Report
System: The UNT Digital Library
Groundwater Quality Assessment Plan for Single-Shell Tank Waste Management Area B-BX-BY at the Hanford Site, Interim Change Notice 3 (open access)

Groundwater Quality Assessment Plan for Single-Shell Tank Waste Management Area B-BX-BY at the Hanford Site, Interim Change Notice 3

This interima change notice updates the sampling schedule.
Date: May 4, 2006
Creator: Narbutovskih, Susan M.
Object Type: Report
System: The UNT Digital Library