Calendar Year 2009 Program Benefits for ENERGY STAR Labeled Products (open access)

Calendar Year 2009 Program Benefits for ENERGY STAR Labeled Products

ENERGY STAR is a voluntary energy efficiency labeling program operated jointly by the Environmental Protection Agency (US EPA) and the U.S. Department of Energy (US DOE), designed to identify and promote energy-efficient products, buildings and practices. Since the program inception in 1992, ENERGY STAR has become a leading international brand for energy efficient products, and currently labels more than thirty products, spanning office equipment, heating, cooling and ventilation equipment, commercial and residential lighting, home electronics, and major appliances. ENERGY STAR's central role in the development of regional, national and international energy programs necessitates an open process whereby its program achievements to date as well as projected future savings are shared with stakeholders. This report presents savings estimates from the use ENERGY STAR labeled products. We present estimates of energy, dollar, and carbon savings achieved by the program in the year 2009, annual forecasts for 2010 and 2011, and cumulative savings estimates for the period 1993 through 2009 and cumulative forecasts for the period 2010 through 2015. Through 2009 the program saved 9.5 Quads of primary energy and avoided the equivalent of 170 million metric tons carbon (MMTC). The forecast for the period 2009-2015 is 11.5 Quads or primary energy saved …
Date: November 15, 2010
Creator: Homan, Gregory K; Sanchez, Marla C. & Brown, Richard E.
Object Type: Report
System: The UNT Digital Library
Calibration and Use of the Canberra iSolo 300G (open access)

Calibration and Use of the Canberra iSolo 300G

This procedure provides instructions for the calibration and use of the Canberra iSolo Low Background Alpha/Beta Counting System (iSolo) that is used for counting air filters and swipe samples. This detector is capable of providing radioisotope identification (e.g., it can discriminate between radon daughters and plutonium). This procedure includes step-by-step instructions for: (1) Performing periodic or daily 'Background' and 'Efficiency QC' checks; (2) Setting-up the iSolo for counting swipes and air filters; (3) Counting swipes and air filters for alpha and beta activity; and (4) Annual calibration.
Date: November 24, 2010
Creator: Smith, T.; Graham, C. L.; Sundsmo, T. & Shingleton, K. L.
Object Type: Report
System: The UNT Digital Library
Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol (open access)

Carbon oxidation state as a metric for describing the chemistry of atmospheric organic aerosol

A detailed understanding of the sources, transformations, and fates of organic species in the environment is crucial because of the central roles that organics play in human health, biogeochemical cycles, and Earth's climate. However, such an understanding is hindered by the immense chemical complexity of environmental mixtures of organics; for example, atmospheric organic aerosol consists of at least thousands of individual compounds, all of which likely evolve chemically over their atmospheric lifetimes. Here we demonstrate the utility of describing organic aerosol (and other complex organic mixtures) in terms of average carbon oxidation state (OSC), a quantity that always increases with oxidation, and is readily measured using state-of-the-art analytical techniques. Field and laboratory measurements of OSC , using several such techniques, constrain the chemical properties of the organics and demonstrate that the formation and evolution of organic aerosol involves simultaneous changes to both carbon oxidation state and carbon number (nC).
Date: November 5, 2010
Creator: Technology, Massachusetts Institute of; Kroll, Jesse H.; Donahue, Neil M.; Jimenez, Jose L.; Kessler, Sean H.; Canagaratna, Manjula R. et al.
Object Type: Article
System: The UNT Digital Library
Carbon Sequestration Monitoring Activities (open access)

Carbon Sequestration Monitoring Activities

In its 'Carbon Sequestration Technology Roadmap and Program Plan 2007' the U.S. Department of Energy (DOE)'s Office of Fossil Energy National Energy Technology Laboratory (NETL) identified as a major objective extended field tests to fully characterize potential carbon dioxide (CO{sub 2}) storage sites and to demonstrate the long-term storage of sequestered carbon (p. 5). Among the challenges in this area are 'improved understanding of CO{sub 2} flow and trapping within the reservoir and the development and deployment of technologies such as simulation models and monitoring systems' (p. 20). The University of Wyoming (UW), following consultations with the NETL, the Wyoming State Geological Survey, and the Governor's office, identified potential for geologic sequestration of impure carbon dioxide (CO{sub 2}) in deep reservoirs of the Moxa Arch. The Moxa Arch is a 120-mile long north-south trending anticline plunging beneath the Wyoming Thrust Belt on the north and bounded on the south by the Uinta Mountains. Several oil and gas fields along the Moxa Arch contain accumulations of natural CO{sub 2}. The largest of these is the La Barge Platform, which encompasses approximately 800 square miles. Several formations may be suitable for storage of impure CO{sub 2} gas, foremost among them the Madison …
Date: November 30, 2010
Creator: Frost, Carol
Object Type: Report
System: The UNT Digital Library
Carbonation of Clay Minerals Exposed to scCO2/Water at 200 degrees and 250 degrees C (open access)

Carbonation of Clay Minerals Exposed to scCO2/Water at 200 degrees and 250 degrees C

To clarify the mechanisms of carbonation of clay minerals, such as bentonite, kaolinite, and soft clay, we exposed them to supercritical carbon dioxide (scCO2)/water at temperatures of 200 and 250 C and pressures of 1500 and 2000 psi for 72- and 107-hours. Bentonite, comprising three crystalline phases, montmorillonite (MMT), anorthoclase-type albite, and quartz was susceptible to reactions with ionic carbonic acid yielded by the interactions between scCO2 and water, particularly MMT and anorthoclase-type albite phases. For MMT, the cation-exchangeable ions, such as Na+ and Ca2+, present in its basal interplanar space, were replaced by proton, H+, from ionic carbonic acid; thereafter, the cations leaching from MMT directly reacted with CO32- as a counter ion of H+ to form carbonate compounds. Such in-situ carbonation process in basal space caused the shrinkage and breakage of the spacing structure within MMT. In contrast, the wet carbonation of anorthoclase-type albite, categorized as rock minerals, entailed the formation of three amorphous by-products, such as carbonates, kaolinite-like compounds, and silicon dioxide. Together, these two different carbonations caused the disintegration and corruption of bentonite. Kaolinite clay containing the amorphous carbonates and silicon dioxide was inert to wet carbonation. We noted only a gain in weight due to …
Date: November 1, 2010
Creator: Sugama, T.; Ecker, L.; Gill, S.; Butcher, T. (BNL) & Bour, D. (AltaRock Energy, Inc.)
Object Type: Report
System: The UNT Digital Library
CEMENTITIOUS BARRIERS PARTNERSHIP ACCOMPLISHMENTS AND RELEVANCE TO THE DOE COMPLEX (open access)

CEMENTITIOUS BARRIERS PARTNERSHIP ACCOMPLISHMENTS AND RELEVANCE TO THE DOE COMPLEX

The Cementitious Barriers Partnership (CBP) was initiated to reduce risk and uncertainties in the performance assessments that directly impact U.S. Department of Energy (DOE) environmental cleanup and closure programs. The CBP is supported by the DOE Office of Environmental Management (DOE-EM) and has been specifically addressing the following critical EM program needs: (i) the long-term performance of cementitious barriers and materials in nuclear waste disposal facilities and (ii) increased understanding of contaminant transport behavior within cementitious barrier systems to support the development and deployment of adequate closure technologies. To accomplish this, the CBP has two initiatives: (1) an experimental initiative to increase understanding of changes in cementitious materials over long times (> 1000 years) over changing conditions and (2) a modeling initiative to enhance and integrate a set of computational tools validated by laboratory and field experimental data to improve understanding and prediction of the long-term performance of cementitious barriers and waste forms used in nuclear applications. In FY10, the CBP developed the initial phase of an integrated modeling tool that would serve as a screening tool which could help in making decisions concerning disposal and tank closure. The CBP experimental programs are underway to validate this tool and provide …
Date: November 15, 2010
Creator: Burns, H.; Langton, C.; Flach, G. & Kosson, D.
Object Type: Article
System: The UNT Digital Library
Challenges, uncertainties and issues facing gas production from gas hydrate deposits (open access)

Challenges, uncertainties and issues facing gas production from gas hydrate deposits

The current paper complements the Moridis et al. (2009) review of the status of the effort toward commercial gas production from hydrates. We aim to describe the concept of the gas hydrate petroleum system, to discuss advances, requirement and suggested practices in gas hydrate (GH) prospecting and GH deposit characterization, and to review the associated technical, economic and environmental challenges and uncertainties, including: the accurate assessment of producible fractions of the GH resource, the development of methodologies for identifying suitable production targets, the sampling of hydrate-bearing sediments and sample analysis, the analysis and interpretation of geophysical surveys of GH reservoirs, well testing methods and interpretation of the results, geomechanical and reservoir/well stability concerns, well design, operation and installation, field operations and extending production beyond sand-dominated GH reservoirs, monitoring production and geomechanical stability, laboratory investigations, fundamental knowledge of hydrate behavior, the economics of commercial gas production from hydrates, and the associated environmental concerns.
Date: November 1, 2010
Creator: Moridis, G. J.; Collett, T. S.; Pooladi-Darvish, M.; Hancock, S.; Santamarina, C.; Boswell, R. et al.
Object Type: Article
System: The UNT Digital Library
Chamber Design for the Laser Inertial Fusion Energy (LIFE) Engine (open access)

Chamber Design for the Laser Inertial Fusion Energy (LIFE) Engine

The Laser Inertial Fusion Energy (LIFE) concept is being designed to operate as either a pure fusion or hybrid fusion-fission system. The present work focuses on the pure fusion option. A key component of a LIFE engine is the fusion chamber subsystem. It must absorb the fusion energy, produce fusion fuel to replace that burned in previous targets, and enable both target and laser beam transport to the ignition point. The chamber system also must mitigate target emissions, including ions, x-rays and neutrons and reset itself to enable operation at 10-15 Hz. Finally, the chamber must offer a high level of availability, which implies both a reasonable lifetime and the ability to rapidly replace damaged components. An integrated design that meets all of these requirements is described herein.
Date: November 30, 2010
Creator: Latkowski, J. F.; Abbott, R. P.; Aceves, S.; Anklam, T.; Badders, D.; Cook, A. W. et al.
Object Type: Article
System: The UNT Digital Library
Characterization of the Wymark CO2 Reservoir: A Natural Analog to Long-Term CO2 Storage at Weyburn (open access)

Characterization of the Wymark CO2 Reservoir: A Natural Analog to Long-Term CO2 Storage at Weyburn

Natural accumulations of CO{sub 2} occur in the Duperow and other Devonian strata on the western flank of the Williston Basin in lithologies very similar to those into which anthropogenic CO{sub 2} is being injected as part of an EOR program in the Weyburn-Midale pool. Previous workers have established the stratgraphic and petrographic similarities between the Duperow and Midale beds (Lake and Whittaker, 2004 and 2006). As the CO{sub 2} accumulations in the Devonian strata may be as old as 50 Ma, this similarity provides confidence in the efficacy of long-term geologic sequestration of CO{sub 2} in the Midale-Weyburn pool. Here we attempt to extend this comparison with whole rock and mineral chemistry using the same sample suite used by Lake and Whittaker. We provide XRD, XRF, and electron microprobe analysis of major constituent minerals along with extensive backscattered electron and x-ray imaging to identify trace phases and silicate minerals. LPNORM analysis is used to quantify modal concentrations of minerals species. Samples from depth intervals where CO{sub 2} has been observed are compared to those where CO{sub 2} was absent, with no systematic differences in mineral composition observed. Gas accumulation can be correlated with sample porosity. In particular gas-bearing samples …
Date: November 22, 2010
Creator: Ryerson, F & Johnson, J
Object Type: Report
System: The UNT Digital Library
The CHASE laboratory search for chameleon dark energy (open access)

The CHASE laboratory search for chameleon dark energy

A scalar field is a favorite candidate for the particle responsible for dark energy. However, few theoretical means exist that can simultaneously explain the observed acceleration of the Universe and evade tests of gravity. The chameleon mechanism, whereby the properties of a particle depend upon the local environment, is one possible avenue. We present the results of the Chameleon Afterglow Search (CHASE) experiment, a laboratory probe for chameleon dark energy. CHASE marks a significant improvement other searches for chameleons both in terms of its sensitivity to the photon/chameleon coupling as well as its sensitivity to the classes of chameleon dark energy models and standard power-law models. Since chameleon dark energy is virtually indistinguishable from a cosmological constant, CHASE tests dark energy models in a manner not accessible to astronomical surveys.
Date: November 1, 2010
Creator: Steffen, Jason H.
Object Type: Article
System: The UNT Digital Library
Chemical Kinetic Models for HCCI and Diesel Combustion (open access)

Chemical Kinetic Models for HCCI and Diesel Combustion

Predictive engine simulation models are needed to make rapid progress towards DOE's goals of increasing combustion engine efficiency and reducing pollutant emissions. These engine simulation models require chemical kinetic submodels to allow the prediction of the effect of fuel composition on engine performance and emissions. Chemical kinetic models for conventional and next-generation transportation fuels need to be developed so that engine simulation tools can predict fuel effects. The objectives are to: (1) Develop detailed chemical kinetic models for fuel components used in surrogate fuels for diesel and HCCI engines; (2) Develop surrogate fuel models to represent real fuels and model low temperature combustion strategies in HCCI and diesel engines that lead to low emissions and high efficiency; and (3) Characterize the role of fuel composition on low temperature combustion modes of advanced combustion engines.
Date: November 15, 2010
Creator: Pitz, W J; Westbrook, C K; Mehl, M & Sarathy, S M
Object Type: Report
System: The UNT Digital Library
Chemistry, phase formation, and catalytic activity of thin palladium-containing oxide films synthesized by plasma-assisted physical vapor deposition (open access)

Chemistry, phase formation, and catalytic activity of thin palladium-containing oxide films synthesized by plasma-assisted physical vapor deposition

The chemistry, microstructure, and catalytic activity of thin films incorporating palladium were studied using scanning and transmission electron microscopies, X-ray diffraction, spectrophotometry, 4-point probe and catalytic tests. The films were synthesized using pulsed filtered cathodic arc and magnetron sputter deposition, i.e. techniques far from thermodynamic equilibrium. Catalytic particles were formed by thermally cycling thin films of the Pd-Pt-O system. The evolution and phase formation in such films as a function of temperature were discussed in terms of the stability of PdO and PtO2 in air. The catalytic efficiency was found to be strongly affected by the chemical composition, with oxidized palladium definitely playing a major role in the combustion of methane. Reactive sputter deposition of thin films in the Pd-Zr-Y-O system allowed us forming microstructures ranging from nanocrystalline zirconia to palladium nanoparticles embedded in a (Zr,Y)4Pd2O matrix. The sequence of phase formation is put in relation to simple thermodynamic considerations.
Date: November 26, 2010
Creator: Anders, Andre
Object Type: Article
System: The UNT Digital Library
The Chicagoland Observatory Underground for Particle Physics cosmic ray veto system (open access)

The Chicagoland Observatory Underground for Particle Physics cosmic ray veto system

A photomultiplier (PMT) readout system has been designed for use by the cosmic ray veto systems of two warm liquid bubble chambers built at Fermilab by the Chicagoland Observatory Underground for Particle Physics (COUPP) collaboration. The systems are designed to minimize the infrastructure necessary for installation. Up to five PMTs can be daisy-chained on a single data link using standard Category 5 network cable. The cables is also serve distribute to low voltage power. High voltage is generated locally on each PMT base. Analog and digital signal processing is also performed locally. The PMT base and system controller design and performance measurements are presented.
Date: November 1, 2010
Creator: Crisler, M.; Hall, J.; Ramberg, E.; Kiper, T. & /Fermilab
Object Type: Article
System: The UNT Digital Library

Clean Energy Policies Analysis: The Role of Policy in Clean Energy Market Transformation

This presentation was written and presented by Elizabeth Doris (NREL) at the November 17 TAP Webinar to provide background detail about how state policies are transforming the clean energy market in different regions of the country.
Date: November 1, 2010
Creator: Doris, E.
Object Type: Presentation
System: The UNT Digital Library
CO2 Capture with Enzyme Synthetic Analogue (open access)

CO2 Capture with Enzyme Synthetic Analogue

Overview of an ongoing, 2 year research project partially funded by APRA-E to create a novel, synthetic analogue of carbonic anhydrase and incorporate it into a membrane for removal of CO2 from flue gas in coal power plants. Mechanism background, preliminary feasibility study results, molecular modeling of analogue-CO2 interaction, and program timeline are provided.
Date: November 8, 2010
Creator: Cordatos, Harry
Object Type: Article
System: The UNT Digital Library
Code-to-Code Benchmarking of the Porflow and Goldsim Contaminant Transport Models Using a Simple 1-D Domain - 11191 (open access)

Code-to-Code Benchmarking of the Porflow and Goldsim Contaminant Transport Models Using a Simple 1-D Domain - 11191

An investigation was conducted to compare and evaluate contaminant transport results of two model codes, GoldSim and Porflow, using a simple 1-D string of elements in each code. Model domains were constructed to be identical with respect to cell numbers and dimensions, matrix material, flow boundary and saturation conditions. One of the codes, GoldSim, does not simulate advective movement of water; therefore the water flux term was specified as a boundary condition. In the other code, Porflow, a steady-state flow field was computed and contaminant transport was simulated within that flow-field. The comparisons were made solely in terms of the ability of each code to perform contaminant transport. The purpose of the investigation was to establish a basis for, and to validate follow-on work that was conducted in which a 1-D GoldSim model developed by abstracting information from Porflow 2-D and 3-D unsaturated and saturated zone models and then benchmarked to produce equivalent contaminant transport results. A handful of contaminants were selected for the code-to-code comparison simulations, including a non-sorbing tracer and several long- and short-lived radionuclides exhibiting both non-sorbing to strongly-sorbing characteristics with respect to the matrix material, including several requiring the simulation of in-growth of daughter radionuclides. The …
Date: November 17, 2010
Creator: Hiergesell, R. & Taylor, G.
Object Type: Article
System: The UNT Digital Library
Codes and Standards Gap Analysis Helps DOE Define Research Priorities (Fact Sheet) (open access)

Codes and Standards Gap Analysis Helps DOE Define Research Priorities (Fact Sheet)

This fact sheet describes NREL's accomplishments in analyzing gaps in codes and standards for alternative vehicle fuels, including hydrogen. Work was performed by the Hydrogen Technologies and Systems Center.
Date: November 1, 2010
Creator: unknown
Object Type: Report
System: The UNT Digital Library
The Cold Dark Matter Search test stand warm electronics card (open access)

The Cold Dark Matter Search test stand warm electronics card

A card which does the signal processing for four SQUID amplifiers and two charge sensitive channels is described. The card performs the same functions as is presently done with two custom 9U x 280mm Eurocard modules, a commercial multi-channel VME digitizer, a PCI to GPIB interface, a PCI to VME interface and a custom built linear power supply. By integrating these functions onto a single card and using the power over Ethernet standard, the infrastructure requirements for instrumenting a Cold Dark Matter Search (CDMS) detector test stand are significantly reduced.
Date: November 1, 2010
Creator: Hines, Bruce; /Colorado U., Denver; Hansen, Sten; /Fermilab; Huber, Martin; /Colorado U., Denver et al.
Object Type: Article
System: The UNT Digital Library
Cold Test Measurements on the GTF Prototype RF Gun (open access)

Cold Test Measurements on the GTF Prototype RF Gun

This report describes Cold Test Measurements on the GTF Prototype RF Gun.
Date: November 29, 2010
Creator: Gierman, S.M.
Object Type: Report
System: The UNT Digital Library
Collaborative Proposal: DUSEL R&D at the Kimballton Underground Facility (ICP-MS Confirmation, Material Assay, and Radon Reduction) (open access)

Collaborative Proposal: DUSEL R&D at the Kimballton Underground Facility (ICP-MS Confirmation, Material Assay, and Radon Reduction)

Experiments measuring rare events, such as neutrinoless double beta (0{nu}{beta}{beta}) decay, and those searching for, or measuring very weakly interacting particles, such as low energy solar neutrino experiments or direct dark matter searches, require ever lower backgrounds; particularly those from radioactive contamination of detector materials. The underground physics community strives to identify and develop materials with radioactive contamination at permissible levels, and to remove radioactive contaminants from materials, but each such material represents a separate dedicated research and development effort. This project attempted to help these research communities by expanding the capabilities in the United States, for indentifying low levels of radioactive contamination in detector materials through gamma ray spectroscopy. Additionally the project tried to make a cross comparison between well established gamma ray spectroscopy techniques for identifying radioactive contaminations and Inductively Coupled Plasma Mass Spectroscopy, which is a relatively new method for searching for uranium and thorium in materials. The project also studied the removal of radioactive radon gas for laboratory air, which showed that an inexpensive technologically simple radon scrubber can potentially be used for homes or businesses with high radon levels even after the employment of other mitigation techniques.
Date: November 30, 2010
Creator: Back, Henning O.
Object Type: Report
System: The UNT Digital Library
Commercial and Industrial Base Intermittent Resource Management Pilot (open access)

Commercial and Industrial Base Intermittent Resource Management Pilot

This scoping study summarizes the challenges with integrating wind and solar generation into the California's electricity grid. These challenges include: Smoothing intra-hour variability; - Absorbing excess renewable energy during over-generation periods; - Addressing morning and evening ramping periods. In addition, there are technical challenges to integrating retail demand response (DR) triggered by the wholesale conditions into the CAISO markets. The study describes the DR programs available to the consumers through the utilities in California and CAISO's ancillary services market because an integration of the wholesale and retail DR requires an understanding of these different offerings and the costs associated with acquiring them. Demand-side active and passive storage systems are proposed as technologies that may be used to mitigate the effects of intermittence due to renewable generation. Commercial building technologies as well as industrial facilities with storage capability are identified as targets for the field tests. Two systems used for ancillary services communications are identified as providing the triggers for DR enablement. Through the field tests, issues related to communication, automation and flexibility of demand-side resources will be explored and the performance of technologies that participate in the field tests will be evaluated. The major outcome of this research is identifying …
Date: November 30, 2010
Creator: Kiliccote, Sila; Sporborg, Pamela; Sheik, Imran; Huffaker, Erich & Piette, Mary Ann
Object Type: Report
System: The UNT Digital Library
Commercial Buildings Partnership Projects - Metered Data Format and Delivery (open access)

Commercial Buildings Partnership Projects - Metered Data Format and Delivery

A number of the Commercial Building Partnership Projects (CBPs) will require metering, monitoring, data analysis and verification of savings after the retrofits are complete. Although monitoring and verification (M&V) agents are free to use any metering and monitoring devices that they chose, the data they collect should be reported to Pacific Northwest National Laboratory (PNNL) in a standard format. PNNL will store the data collected in its CBP database for further use by PNNL and U.S. Department of Energy. This document describes the data storage process and the deliver format of the data from the M&V agents.
Date: November 16, 2010
Creator: Katipamula, Srinivas
Object Type: Report
System: The UNT Digital Library
Compact fission counter for DANCE (open access)

Compact fission counter for DANCE

The Detector for Advanced Neutron Capture Experiments (DANCE) consists of 160 BF{sub 2} crystals with equal solid-angle coverage. DANCE is a 4{pi} {gamma}-ray calorimeter and designed to study the neutron-capture reactions on small quantities of radioactive and rare stable nuclei. These reactions are important for the radiochemistry applications and modeling the element production in stars. The recognition of capture event is made by the summed {gamma}-ray energy which is equivalent of the reaction Q-value and unique for a given capture reaction. For a selective group of actinides, where the neutron-induced fission reaction competes favorably with the neutron capture reaction, additional signature is needed to distinguish between fission and capture {gamma} rays for the DANCE measurement. This can be accomplished by introducing a detector system to tag fission fragments and thus establish a unique signature for the fission event. Once this system is implemented, one has the opportunity to study not only the capture but also fission reactions. A parallel-plate avalanche counter (PPAC) has many advantages for the detection of heavy charged particles such as fission fragments. These include fast timing, resistance to radiation damage, and tolerance of high counting rate. A PPAC also can be tuned to be insensitive to …
Date: November 6, 2010
Creator: Wu, C. Y.; Chyzh, A.; Kwan, E.; Henderson, R.; Gostic, J.; Carter, D. et al.
Object Type: Report
System: The UNT Digital Library
Comparative Gamma Spectroscopy with SrI2(Eu), GYGAG(Ce) and Bi-loaded Plastic Scintillators (open access)

Comparative Gamma Spectroscopy with SrI2(Eu), GYGAG(Ce) and Bi-loaded Plastic Scintillators

We are developing new scintillator materials that offer potential for high resolution gamma ray spectroscopy at low cost. Single crystal SrI{sub 2}(Eu) offers {approx}3% resolution at 662 keV, in sizes of {approx}1 in{sup 3}. We have developed ceramics processing technology allowing us to achieve cubic inch scale transparent ceramic scintillators offering gamma spectroscopy performance superior to NaI(Tl). We fabricated a bismuth-loaded plastic scintillator that demonstrates energy resolution of {approx}8% at 662 keV in small sizes. Gamma ray spectroscopy can be used to identify the presence of weak radioactive sources within natural background. The ability to discriminate close-lying spectral lines is strongly dependent upon the energy resolution of the detector. In addition to excellent energy resolution, large volume detectors are needed to acquire sufficient events, for example, to identify a radioactive anomaly moving past a detector. We have employed a 'directed search' methodology for identifying potential scintillator materials candidates, resulting in the discovery of Europium-doped Strontium Iodide, SrI{sub 2}(Eu), Cerium-doped Gadolinium Garnet, GYGAG(Ce), and Bismuth-loaded Polymers. These scintillators possess very low self-radioactivity, offer energy resolution of 3-8% at 662 keV, and have potential to be grown cost-effectively to sizes similar to the most widely deployed gamma spectroscopy scintillator, Thallium-doped Sodium Iodide, …
Date: November 19, 2010
Creator: Cherepy, N J
Object Type: Article
System: The UNT Digital Library