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Pediatric functional magnetic resonance neuroimaging: tactics for encouraging task compliance (open access)

Pediatric functional magnetic resonance neuroimaging: tactics for encouraging task compliance

This article discusses tactics for encouraging compliance in pediatric functional magnetic resonance neuroimaging.
Date: May 6, 2011
Creator: Schlund, Michael W.; Cataldo, Michael F.; Siegle, Greg J.; Ladouceur, Cecile D.; Silk, Jennifer S.; Forbes, Erika E. et al.
System: The UNT Digital Library
Marketing to Your Community: Becoming a Destination (open access)

Marketing to Your Community: Becoming a Destination

Article on marketing your library collection to your community and becoming a destination for information.
Date: December 6, 2011
Creator: Sears, Suzanne
System: The UNT Digital Library
A Noisy 10GB Provenance Database (open access)

A Noisy 10GB Provenance Database

Provenance of scientific data is a key piece of the metadata record for the data's ongoing discovery and reuse. Provenance collection systems capture provenance on the fly, however, the protocol between application and provenance tool may not be reliable. Consequently, the provenance record can be partial, partitioned, and simply inaccurate. We use a workflow emulator that models faults to construct a large 10GB database of provenance that we know is noisy (that is, has errors). We discuss the process of generating the provenance database, and show early results on the kinds of provenance analysis enabled by the large provenance.
Date: June 6, 2011
Creator: Cheah, You-Wei; Plale, Beth; Kendall-Morwick, Joey; Leake, David & Ramakrishnan, Lavanya
System: The UNT Digital Library
Commissioning: A Highly Cost-Effective Building Energy Management Strategy (open access)

Commissioning: A Highly Cost-Effective Building Energy Management Strategy

Quality assurance and optimization are essential elements of any serious technological endeavor, including efforts to improve energy efficiency. Commissioning is an important tool in this respect. The aim of commissioning new buildings is to ensure that they deliver-if not exceed-the performance and energy savings promised by their design. When applied to existing buildings, one-time or repeated commissioning (often called retrocommissioning) identifies the almost inevitable drift in energy performance and puts the building back on course, often surpassing the original design intent. In both contexts, commissioning is a systematic, forensic approach to improving performance, rather than a discrete technology.
Date: January 6, 2011
Creator: Mills, Evan
System: The UNT Digital Library
MARIANE: MApReduce Implementation Adapted for HPC Environments (open access)

MARIANE: MApReduce Implementation Adapted for HPC Environments

MapReduce is increasingly becoming a popular framework, and a potent programming model. The most popular open source implementation of MapReduce, Hadoop, is based on the Hadoop Distributed File System (HDFS). However, as HDFS is not POSIX compliant, it cannot be fully leveraged by applications running on a majority of existing HPC environments such as Teragrid and NERSC. These HPC environments typicallysupport globally shared file systems such as NFS and GPFS. On such resourceful HPC infrastructures, the use of Hadoop not only creates compatibility issues, but also affects overall performance due to the added overhead of the HDFS. This paper not only presents a MapReduce implementation directly suitable for HPC environments, but also exposes the design choices for better performance gains in those settings. By leveraging inherent distributed file systems' functions, and abstracting them away from its MapReduce framework, MARIANE (MApReduce Implementation Adapted for HPC Environments) not only allows for the use of the model in an expanding number of HPCenvironments, but also allows for better performance in such settings. This paper shows the applicability and high performance of the MapReduce paradigm through MARIANE, an implementation designed for clustered and shared-disk file systems and as such not dedicated to a specific …
Date: July 6, 2011
Creator: Fadika, Zacharia; Dede, Elif; Govindaraju, Madhusudhan & Ramakrishnan, Lavanya
System: The UNT Digital Library
Optical modeling of Fresnel zoneplate microscopes (open access)

Optical modeling of Fresnel zoneplate microscopes

Defect free masks remain one of the most significant challenges facing the commercialization of extreme ultraviolet (EUV) lithography. Progress on this front requires high-performance wavelength-specific metrology of EUV masks, including high-resolution and aerial-image microscopy performed near the 13.5 nm wavelength. Arguably the most cost-effective and rapid path to proliferating this capability is through the development of Fresnel zoneplate-based microscopes. Given the relative obscurity of such systems, however, modeling tools are not necessarily optimized to deal with them and their imaging properties are poorly understood. Here we present a modeling methodology to analyze zoneplate microscopes based on commercially available optical modeling software and use the technique to investigate the imaging performance of an off-axis EUV microscope design. The modeling predicts that superior performance can be achieved by tilting the zoneplate, making it perpendicular to the chief ray at the center of the field, while designing the zoneplate to explicitly work in that tilted plane. Although the examples presented here are in the realm of EUV mask inspection, the methods described and analysis results are broadly applicable to zoneplate microscopes in general, including full-field soft-x-ray microscopes rou tinely used in the synchrotron community.
Date: April 6, 2011
Creator: Naulleau, Patrick; Mochi, Iacopo & Goldberg, Kenneth A.
System: The UNT Digital Library
Construction and Operational Experience with a Superconducting Octupole Used to Trap Antihydrogen (open access)

Construction and Operational Experience with a Superconducting Octupole Used to Trap Antihydrogen

A superconducting octupole magnet has seen extensive service as part of the ALPHA experiment at CERN. ALPHA has trapped antihydrogen, a crucial step towards performing precision measurements of anti-atoms. The octupole was made at the Direct Wind facility by the Superconducting Magnet Division at Brookhaven National Laboratory. The magnet was wound with a six-around-one NbTi cable about 1 mm in diameter. It is about 300 mm long, with a radius of 25 mm and a peak field at the conductor of 4.04 T. Specific features of the magnet, including a minimal amount of material in the coil and coil ends with low multipole content, were advantageous to its use in ALPHA. The magnet was operated for six months a year for five years. During this time it underwent about 900 thermal cycles (between 4K and 100K). A novel operational feature is that during the course of data-taking the magnet was repeatedly shut off from its 950 A operating current. The magnet quenches during the shutoff, with a decay constant of 9 ms. Over the course of the five years, the magnet was deliberately quenched many thousands of times. It still performs well.
Date: September 6, 2011
Creator: Wanderer, P.; Escallier, J.; Marone, A. & Parker, B.
System: The UNT Digital Library
Direct observation of two-step crystallization in nanoparticle superlattice formation (open access)

Direct observation of two-step crystallization in nanoparticle superlattice formation

Direct imaging of nanoparticle solutions by liquid phase transmission electron microscopy has enabled unique in-situ studies of nanoparticle motion and growth. In the present work, we report on real-time formation of two-dimensional nanoparticle arrays in the very low diffusive limit, where nanoparticles are mainly driven by capillary forces and solvent fluctuations. We find that superlattice formation appears to be segregated into multiple regimes. Initially, the solvent front drags the nanoparticles, condensing them into an amorphous agglomerate. Subsequently, the nanoparticle crystallization into an array is driven by local fluctuations. Following the crystallization event, superlattice growth can also occur via the addition of individual nanoparticles drawn from outlying regions by different solvent fronts. The dragging mechanism is consistent with simulations based on a coarse-grained lattice gas model at the same limit.
Date: October 6, 2011
Creator: Park, Jungwon; Zheng, Haimei; Lee, Won Chul; Geissler, Phillip L.; Rabani, Eran & Alivisatos, A. Paul
System: The UNT Digital Library
3rd ASM Conference on Cell-Cell Communication in Bacteria (open access)

3rd ASM Conference on Cell-Cell Communication in Bacteria

This report summarizes the final program and provides the abstracts presented at the fourth American Society of Microbiology-sponsored conference on Cell-cell Communication in Bacteria, held November 6-9, 2011 in Miami, Florida. Bacteria are the paradigm for unicellular life, yet they also exhibit elaborate coordinated behaviors that often defy unicellularity. Research over the past two decades has revealed that a wide range of microbes communicate by diverse mechanisms. In most cases these microbial conversations occur through the exchange of diffusible signals, although there are also clear examples of contact-dependent communication. Many microbes use these signaling mechanisms to monitor and respond to population density, a process often described as quorum sensing. Interbacterial communication is not, however restricted to quorum sensing mechanisms, and there is mounting evidence that signaling can function in a range of different capacities. Communication between microorganisms has profound impacts on host interactions, as pathogens and commensals often regulate factors critical for interaction with their hosts via signal production and perception. The CCCB-4 conference provided a unique forum for the discussion, dissemination and exchange of new information and ideas among researchers working within this rapidly developing, yet mature field. Sessions were arranged around topics such as: the diversity of signal …
Date: November 6, 2011
Creator: Nalker, Lisa K.
System: The UNT Digital Library
Synthesis and characterization of a nanocrystalline diamond aerogel (open access)

Synthesis and characterization of a nanocrystalline diamond aerogel

Aerogel materials have myriad scientific and technological applications due to their large intrinsic surface areas and ultralow densities. However, creating a nanodiamond aerogel matrix has remained an outstanding and intriguing challenge. Here we report the high-pressure, high-temperature synthesis of a diamond aerogel from an amorphous carbon aerogel precursor using a laser-heated diamond anvil cell. Neon is used as a chemically inert, near-hydrostatic pressure medium that prevents collapse of the aerogel under pressure by conformally filling the aerogel's void volume. Electron and X-ray spectromicroscopy confirm the aerogel morphology and composition of the nanodiamond matrix. Time-resolved photoluminescence measurements of recovered material reveal the formation of both nitrogen- and silicon- vacancy point-defects, suggesting a broad range of applications for this nanocrystalline diamond aerogel.
Date: July 6, 2011
Creator: Pauzauskie, Peter J.; Crowhurst, Jonathan C.; Worsley, Marcus A.; Laurence, Ted A.; Kilcoyne, A. L. David; Wang, Yinmin et al.
System: The UNT Digital Library
Acceleration of Radiance for Lighting Simulation by Using Parallel Computing with OpenCL (open access)

Acceleration of Radiance for Lighting Simulation by Using Parallel Computing with OpenCL

We report on the acceleration of annual daylighting simulations for fenestration systems in the Radiance ray-tracing program. The algorithm was optimized to reduce both the redundant data input/output operations and the floating-point operations. To further accelerate the simulation speed, the calculation for matrix multiplications was implemented using parallel computing on a graphics processing unit. We used OpenCL, which is a cross-platform parallel programming language. Numerical experiments show that the combination of the above measures can speed up the annual daylighting simulations 101.7 times or 28.6 times when the sky vector has 146 or 2306 elements, respectively.
Date: September 6, 2011
Creator: Zuo, Wangda; McNeil, Andrew; Wetter, Michael & Lee, Eleanor
System: The UNT Digital Library
Selenium hyperaccumulation offers protection from cell disruptor herbivores (open access)

Selenium hyperaccumulation offers protection from cell disruptor herbivores

Hyperaccumulation, the rare capacity of certain plant species to accumulate toxic trace elements to levels several orders of magnitude higher than other species growing on the same site, is thought to be an elemental defense mechanism against herbivores and pathogens. Previous research has shown that selenium (Se) hyperaccumulation protects plants from a variety of herbivores and pathogens. Selenium hyperaccumulating plants sequester Se in discrete locations in the leaf periphery, making them potentially more susceptible to some herbivore feeding modes than others. In this study we investigate the protective function of Se in the Se hyperaccumulators Stanleya pinnata and Astragalus bisulcatus against two cell disrupting herbivores, the western flower thrips (Frankliniella occidentalis) and the two-spotted spider mite (Tetranychus urticae). Astragalus bisulcatus and S. pinnata with high Se concentrations (greater than 650 mg Se kg{sup -1}) were less subject to thrips herbivory than plants with low Se levels (less than 150 mg Se kg{sup -1}). Furthermore, in plants containing elevated Se levels, leaves with higher concentrations of Se suffered less herbivory than leaves with less Se. Spider mites also preferred to feed on low-Se A. bisulcatus and S. pinnata plants rather than high-Se plants. Spider mite populations on A. bisulcatus decreased after …
Date: July 6, 2011
Creator: Quinn, Colin F; Freeman, John L; Reynolds, Ray JB; Cappa, Jennifer J; Fakra, Sirine C; Marcus, Matthew A et al.
System: The UNT Digital Library
Reverse engineering the ancient ceramic technology based on X-ray fluorescence spectromicroscopy (open access)

Reverse engineering the ancient ceramic technology based on X-ray fluorescence spectromicroscopy

We present results of X-ray fluorescence (XRF) microprobe analyses of ancient ceramic cross-sections aiming at deciphering the different firing protocols used for their production. Micro-focused XRF elemental mapping, Fe chemical mapping and Fe K-edge X-ray absorption near edge structure spectroscopy were performed on pre-sigillata ceramics from southern Gaul, and terra Sigillata vessels from Italy and southern Gaul. Pieces from the different workshops and regions showed significant difference in the starting clay material, clay conditioning and kiln firing condition. By contrast, sherds from the same workshop exhibited more subtle differences and possible misfirings. Understanding the precise firing conditions and protocols would allow recreation of kilns for various productions. Furthermore, evolution and modification of kiln design would shed some light on how ancient potters devised solutions to diverse technological problems they encountered.
Date: July 6, 2011
Creator: Sciau, Philippe; Leon, Yoanna; Goudeau, Philippe; Fakra, Sirine C.; Webb, Sam & Mehta, Apurva
System: The UNT Digital Library
Triple Modulator-Chicane Scheme for Seeding Sub-Nanometer X-Ray Free Electron Lasers (open access)

Triple Modulator-Chicane Scheme for Seeding Sub-Nanometer X-Ray Free Electron Lasers

We propose a novel triple modulator-chicane (TMC) scheme to convert external input seed to shorter wavelengths. In the scheme high power seed lasers are used in the first and third modulator while only very low power seed is used in the second modulator. By properly choosing the parameters of the lasers and chicanes, we show that ultrahigh harmonics can be generated in the TMC scheme while simultaneously keeping the energy spread growth much smaller than beam's initial slice energy spread. As an example we show the feasibility of generating significant bunching at 1 nm and below from a low power ({approx} 100 kW) high harmonic generation seed at 20 nm assisted by two high power ({approx} 100 MW) UV lasers at 200 nm while keeping the energy spread growth within 40%. The supreme up-frequency conversion efficiency of the proposed TMC scheme together with its unique advantage in maintaining beam energy spread opens new opportunities for generating fully coherent x-rays at sub-nanometer wavelength from external seeds.
Date: July 6, 2011
Creator: Xiang, Dao & Stupakov, Gennady
System: The UNT Digital Library
The Products of the Thermal Decomposition of CH3CHO (open access)

The Products of the Thermal Decomposition of CH3CHO

We have used a heated 2 cm x 1 mm SiC microtubular (mu tubular) reactor to decompose acetaldehyde: CH3CHO + DELTA --> products. Thermal decomposition is followed at pressures of 75 - 150 Torr and at temperatures up to 1700 K, conditions that correspond to residence times of roughly 50 - 100 mu sec in the mu tubular reactor. The acetaldehyde decomposition products are identified by two independent techniques: VUV photoionization mass spectroscopy (PIMS) and infrared (IR) absorption spectroscopy after isolation in a cryogenic matrix. Besides CH3CHO, we have studied three isotopologues, CH3CDO, CD3CHO, and CD3CDO. We have identified the thermal decomposition products CH3(PIMS), CO (IR, PIMS), H (PIMS), H2 (PIMS), CH2CO (IR, PIMS), CH2=CHOH (IR, PIMS), H2O (IR, PIMS), and HC=CH (IR, PIMS). Plausible evidence has been found to support the idea that there are at least three different thermal decomposition pathways for CH3CHO: Radical decomposition: CH3CHO + DELTA --> CH3 + [HCO] --> CH3 + H + CO Elimination: CH3CHO + DELTA --> H2 + CH2=C=O. Isomerization/elimination: CH3CHO + DELTA --> [CH2=CH-OH] --> HC=CH + H2O. Both PIMS and IR spectroscopy show compelling evidence for the participation of vinylidene, CH2=C:, as an intermediate in the decomposition of vinyl …
Date: April 6, 2011
Creator: Vasiliou, AnGayle; Piech, Krzysztof M.; Zhang, Xu; Nimlos, Mark R.; Ahmed, Musahid; Golan, Amir et al.
System: The UNT Digital Library
Calibration of LSST Instrumental and Atmospheric Photometric Passbands (open access)

Calibration of LSST Instrumental and Atmospheric Photometric Passbands

The Large Synoptic Survey Telescope (LSST) will continuously image the entire sky visible from Cerro Pachon in northern Chile every 3-4 nights throughout the year. The LSST will provide data for a broad range of science investigations that require better than 1% photometric precision across the sky (repeatability and uniformity) and a similar accuracy of measured broadband color. The fast and persistent cadence of the LSST survey will significantly improve the temporal sampling rate with which celestial events and motions are tracked. To achieve these goals, and to optimally utilize the observing calendar, it will be necessary to obtain excellent photometric calibration of data taken over a wide range of observing conditions - even those not normally considered 'photometric'. To achieve this it will be necessary to routinely and accurately measure the full optical passband that includes the atmosphere as well as the instrumental telescope and camera system. The LSST mountain facility will include a new monochromatic dome illumination projector system to measure the detailed wavelength dependence of the instrumental passband for each channel in the system. The facility will also include an auxiliary spectroscopic telescope dedicated to measurement of atmospheric transparency at all locations in the sky during LSST …
Date: July 6, 2011
Creator: Burke, David L.; Axelrod, T.; Barrau, Aurelien; Baumont, Sylvain; Blondin, Stephane; Claver, Chuck et al.
System: The UNT Digital Library
ALPHA SPECTROMETRIC EVALUATION OF SRM-995 AS A POTENTIAL URANIUM/THORIUM DOUBLE TRACER SYSTEM FOR AGE-DATING URANIUM MATERIALS (open access)

ALPHA SPECTROMETRIC EVALUATION OF SRM-995 AS A POTENTIAL URANIUM/THORIUM DOUBLE TRACER SYSTEM FOR AGE-DATING URANIUM MATERIALS

Uranium-233 (t{sub 1/2} {approx} 1.59E5 years) is an artificial, fissile isotope of uranium that has significant importance in nuclear forensics. The isotope provides a unique signature in determining the origin and provenance of uranium-bearing materials and is valuable as a mass spectrometric tracer. Alpha spectrometry was employed in the critical evaluation of a {sup 233}U standard reference material (SRM-995) as a dual tracer system based on the in-growth of {sup 229}Th (t{sub 1/2} {approx} 7.34E3 years) for {approx}35 years following radiochemical purification. Preliminary investigations focused on the isotopic analysis of standards and unmodified fractions of SRM-995; all samples were separated and purified using a multi-column anion-exchange scheme. The {sup 229}Th/{sup 233}U atom ratio for SRM-995 was found to be 1.598E-4 ({+-} 4.50%) using recovery-corrected radiochemical methods. Using the Bateman equations and relevant half-lives, this ratio reflects a material that was purified {approx} 36.8 years prior to this analysis. The calculated age is discussed in contrast with both the date of certification and the recorded date of last purification.
Date: December 6, 2011
Creator: Beals, D.
System: The UNT Digital Library
RECLAMATION OF RADIOACTIVE MATERIAL PACKAGING COMPONENTS (open access)

RECLAMATION OF RADIOACTIVE MATERIAL PACKAGING COMPONENTS

Radioactive material packages are withdrawn from use for various reasons; loss of mission, decertification, damage, replacement, etc. While the packages themselves may be decertified, various components may still be able to perform to their required standards and find useful service. The Packaging Technology and Pressurized Systems group of the Savannah River National Laboratory has been reducing the cost of producing new Type B Packagings by reclaiming, refurbishing, and returning to service the containment vessels from older decertified packagings. The program and its benefits are presented.
Date: June 6, 2011
Creator: Abramczyk, G.; Nathan, S.; Loftin, B. & Bellamy, S.
System: The UNT Digital Library
Max Tech Appliance Design: Potential for Maximizing U.S. Energy Savings through Standards (open access)

Max Tech Appliance Design: Potential for Maximizing U.S. Energy Savings through Standards

This study surveyed the technical potential for efficiency improvements in 150 categories of appliances and equipment representing 33 quads of primary energy use across the US economy in 2010 and (1) documented efficient product designs, (2) identified the most promising cross-cutting strategies, and (3) ranked national energy savings potential by end use. Savings were estimated using a method modeled after US Department of Energy priority-setting reports - simplified versions of the full technical and economic analyses performed for rulemakings. This study demonstrates that large savings are possible by replacing products at the end-of-life with ultra-efficient models that use existing technology. Replacing the 50 top energy-saving end-uses (constituting 30 quads of primary energy consumption in 2010) with today's best-on-market equivalents would save {approx}200 quads of US primary energy over 30 years (25% of consumption anticipated there from). For the 29 products for maximum feasible savings potential could be estimated, the savings were twice as high. These results demonstrate that pushing ultra-efficient products to market could significantly escalate carbon emission reductions and is a viable strategy for sustaining large emissions reductions through standards. The results of this analysis were used by DOE for new coverage prioritization, to identify key opportunities for product …
Date: May 6, 2011
Creator: Garbesi, Karina; Desroches, Louis-Benoit; Bolduc, Christopher; Burch, Gabriel; Hosseinzadeh, Griffin & Saltiel, Seth
System: The UNT Digital Library
Plastic Behavior of Polycrystalline Tantalum in the 5 X 10^7/S Regime (open access)

Plastic Behavior of Polycrystalline Tantalum in the 5 X 10^7/S Regime

The goal of this experiment is to investigate the plastic response of Tantalum to dynamic loading at high strain rates. The samples used were derived from high purity rolled plate, polished down to thicknesses in the range 25-100 {micro}m. Dynamic loading was applied by direct laser ablation of the sample, with pulses up to 10 ns long, at the Jupiter Laser Facility. The elastic-plastic wave structure was measured using two line VISAR systems of different sensitivity, and strain rates were inferred from the rise time of the waves. The elastic wave amplitudes indicated flow stresses between 2 and 3 GPa, depending on the sample thickness. Samples were recovered for post-shot metallographic analysis.
Date: August 6, 2011
Creator: Hammel, B. D.; Swift, D. C.; El-Dasher, B. S.; Kumar, M.; Collins, G. W. & Florando, J.
System: The UNT Digital Library
MAINTAINING HIGH RESOLUTION MASS SPECTROMETRY CAPABILITIES FOR NATIONAL NUCLEAR SECURITY ADMINISTRATION APPLICATIONS (open access)

MAINTAINING HIGH RESOLUTION MASS SPECTROMETRY CAPABILITIES FOR NATIONAL NUCLEAR SECURITY ADMINISTRATION APPLICATIONS

The Department of Energy (DOE) National Nuclear Security Administration (NNSA) has a specialized need for analyzing low mass gas species at very high resolutions. The currently preferred analytical method is electromagnetic sector mass spectrometry. This method allows the NNSA Nuclear Security Enterprise (NSE) to resolve species of similar masses down to acceptable minimum detection limits (MDLs). Some examples of these similar masses are helium-4/deuterium and carbon monoxide/nitrogen. Through the 1980s and 1990s, there were two vendors who supplied and supported these instruments. However, with declining procurements and down turns in the economy, the supply of instruments, service and spare parts from these vendors has become less available, and in some cases, nonexistent. The largest NSE user of this capability is the Savannah River Site (SRS), located near Aiken, South Carolina. The Research and Development Engineering (R&DE) Group in the Savannah River National Laboratory (SRNL) investigated the areas of instrument support that were needed to extend the life cycle of these aging instruments. Their conclusions, as to the focus areas of electromagnetic sector mass spectrometers to address, in order of priority, were electronics, software and hardware. Over the past 3-5 years, the R&DE Group has designed state of the art electronics …
Date: June 6, 2011
Creator: Wyrick, S.; Cordaro, J.; Reeves, G.; Mcintosh, J.; Mauldin, C.; Tietze, K. et al.
System: The UNT Digital Library
SHIPMENT OF TWO DOE-STD-3013 CONTAINERS IN A 9977 TYPE B PACKAGE (open access)

SHIPMENT OF TWO DOE-STD-3013 CONTAINERS IN A 9977 TYPE B PACKAGE

The 9977 is a certified Type B Packaging authorized to ship uranium and plutonium in metal and oxide forms. Historically, the standard container for these materials has been the DOE-STD-3013 which was specifically designed for the long term storage of plutonium bearing materials. The Department of Energy has used the 9975 Packaging containing a single 3013 container for the transportation and storage of these materials. In order to reduce container, shipping, and storage costs, the 9977 Packaging is being certified for transportation and storage of two 3013 containers. The challenges and risks of this content and the 9977s ability to meet the Code of Federal Regulations for the transport of these materials are presented.
Date: June 6, 2011
Creator: Abramczyk, G.; Bellamy, S.; Loftin, B. & Nathan, S.
System: The UNT Digital Library
SHIPMENT OF NON-TRADITIONAL CONTENTS IN THE 9977 TYPE B PACKAGE (open access)

SHIPMENT OF NON-TRADITIONAL CONTENTS IN THE 9977 TYPE B PACKAGE

The 9977 is a certified Type B Packaging authorized to ship uranium and plutonium in metal and oxide forms. These materials are typically confined within metallic containers designed for ease of handling and to prevent the spread of contamination. The Pacific Northwest National Laboratory (PNNL) uses Pu and U sources for the training of domestic and international customs agents in the identification and detection of radioactive materials (RAM). These materials are packed in polycarbonate containers which permit the trainees to view the RAM. The safety basis was made to authorize the use of these unusual containers. The inclusion of the PNNL Training Source Contents into the 9977 Packaging imposed unique conditions previously unanalyzed. The use of polycarbonate as a content container material, while different from any configuration previously considered, does not raise any safety issues with the package which continues to operate with a large safety margin for temperatures, pressures, containment, dose rates, and subcriticality.
Date: June 6, 2011
Creator: Abramczyk, G.; Loftin, B.; Bellamy, S. & Nathan, S.
System: The UNT Digital Library
Status of EXO-200 (open access)

Status of EXO-200

EXO-200 is the first phase of the Enriched Xenon Observatory (EXO) experiment, which searches for neutrinoless double beta decay in {sup 136}Xe to measure the mass and probe the Majorana nature of the neutrino. EXO-200 consists of 200 kg of liquid Xe enriched to 80% in {sup 136}Xe in an ultra-low background TPC. Energy resolution is enhanced through the simultaneous collection of scintillation light using Large Area Avalanche Photodiodes (LAAPD's) and ionization charge. It is being installed at the WIPP site in New Mexico, which provides a 2000 meter water-equivalent overburden. EXO-200 will begin taking data in 2009, with the expected two-year sensitivity to the half-life for neutrinoless double beta decay of 6.4 x 10{sup 25} years. According to the most recent nuclear matrix element calculations, this corresponds to an effective Majorana neutrino mass of 0.13 to 0.19 eV. It will also measure the two neutrino mode for the first time in {sup 136}Xe.
Date: December 6, 2011
Creator: Ackerman, Nicole
System: The UNT Digital Library