Theoretical interpretation of high-energy nuclear collisions. (open access)

Theoretical interpretation of high-energy nuclear collisions.

Nuclear collisions are interpreted theoretically. The nuclear equation of state is studied in a wide energy range. Subnucleonic degrees of freedom are invoked at high energy densities and at short length-scales. Questions of dynamical collision simulations are investigated. Direct support is provided for experiment in the form of collaborative projects. The major objective of this nuclear theory program is a better understanding of the properties of strongly interacting matter on the nuclear energy scale, as manifested in high-energy heavy-ion collisions.
Date: 2010~
Creator: Fai, G.
Object Type: Report
System: The UNT Digital Library
Synthesis and Characterization of Oxide Feedstock Powders for the Fuel Cycle R&D Program (open access)

Synthesis and Characterization of Oxide Feedstock Powders for the Fuel Cycle R&D Program

Nuclear fuel feedstock properties, such as physical, chemical, and isotopic characteristics, have a significant impact on the fuel fabrication process and, by extension, the in-reactor fuel performance. This has been demonstrated through studies with UO{sub 2} spanning greater than 50 years. The Fuel Cycle R&D Program with The Department of Energy Office of Nuclear Energy has initiated an effort to develop a better understanding of the relationships between oxide feedstock, fresh fuel properties, and in-reactor fuel performance for advanced mixed oxide compositions. Powder conditioning studies to enable the use of less than ideal powders for ceramic fuel pellet processing are ongoing at Los Alamos National Laboratory (LANL) and an understanding of methods to increase the green density and homogeneity of pressed pellets has been gained for certain powders. Furthermore, Oak Ridge National Laboratory (ORNL) is developing methods for the co-conversion of mixed oxides along with techniques to analyze the degree of mixing. Experience with the fabrication of fuel pellets using co-synthesized multi-constituent materials is limited. In instances where atomically mixed solid solutions of two or more species are needed, traditional ceramic processing methods have been employed. Solution-based processes may be considered viable synthesis options, including co-precipitation (AUPuC), direct precipitation, direct-conversion …
Date: September 1, 2010
Creator: Voit, Stewart L.; Vedder, Raymond James & Johnson, Jared A.
Object Type: Report
System: The UNT Digital Library
Quantum Simulations for Dense Matter (open access)

Quantum Simulations for Dense Matter

High pressure systems are important, for example, to understand the interiors of giant planets (Jupiter and Saturn), for experiments at NIF (the National Ignition Facility at Livermore) related to inertially confined fusion and for other interests of DOE. In this project, we are developing innovative simulation methods (Quantum Monte Carlo methods) to allow more accurate calculation of properties of systems under extreme conditions of pressure and temperature. These methods can use the power of current day supercomputers made of very many processors, starting from the basic equations of physics to model quantum phenomena important at the microscopic scale. During the grant period, we have settled two important questions of the physics of hydrogen and helium under extreme conditions. We have found the pressures and temperatures when hydrogen and helium mix together; this is important to understand the difference of the interiors of the planets Jupiter and Saturn. Secondly, we have shown that there exists a sharp transition as a function of pressure between molecular and atomic liquid hydrogen at temperatures below 2000K. This prediction can be confirmed with high pressure experiments.
Date: June 7, 2010
Creator: Ceperley, David M.
Object Type: Report
System: The UNT Digital Library
Photovoltaics (PV) as an Eligible Measure in Residential PACE Programs: Benefits and Challenges (Fact Sheet) (open access)

Photovoltaics (PV) as an Eligible Measure in Residential PACE Programs: Benefits and Challenges (Fact Sheet)

Property Assessed Clean Energy (PACE) financing is one of several new financial models broadening access to clean energy by addressing the barrier of initial capital cost. The majority of the PACE programs in the market today include PV as an eligible measure. PV appeals to homeowners as a way to reduce utility bills, self-generate sustainable power, increase energy independence and demonstrate a commitment to the environment. If substantial state incentives for PV exist, PV projects can be economic under PACE, especially when partnered with good net metering policies. At the same time, PV is expensive relative to other eligible measures with a return on investment horizon that might exceed program targets. This fact sheet reviews the benefits and potential challenges of including PV in PACE programs.
Date: June 1, 2010
Creator: Coughlin, J.
Object Type: Report
System: The UNT Digital Library
Technical Project Plan for The Enhanced Thermal Conductivity of Oxide Fuels Through the Addition of High Thermal Conductivity Fibers and Microstructural Engineering (open access)

Technical Project Plan for The Enhanced Thermal Conductivity of Oxide Fuels Through the Addition of High Thermal Conductivity Fibers and Microstructural Engineering

The commercial nuclear power industry is investing heavily in advanced fuels that can produce higher power levels with a higher safety margin and be produced at low cost. Although chemically stable and inexpensive to manufacture, the in-core performance of UO{sub 2} fuel is limited by its low thermal conductivity. There will be enormous financial benefits to any utility that can exploit a new type of fuel that is chemically stable, has a high thermal conductivity, and is inexpensive to manufacture. At reactor operating temperatures, UO{sub 2} has a very low thermal conductivity (<5 W/m {center_dot}K), which decreases with temperature and fuel burnup. This low thermal conductivity limits the rate at which energy can be removed from the fuel, thus limiting the total integrated reactor power. If the fuel thermal conductivity could be increased, nuclear reactors would be able to operate at higher powers and larger safety margins thus decreasing the overall cost of electricity by increasing the power output from existing reactors and decreasing the number of new electrical generating plants needed to meet base load demand. The objective of the work defined herein is to produce an advanced nuclear fuel based on the current UO{sub 2} fuel with superior …
Date: September 1, 2010
Creator: Hollenbach, Daniel F.; Ott, Larry J.; Besmann, Theodore M.; Armstrong, Beth L.; Wereszczak, Andrew A.; Lin, Hua-Tay et al.
Object Type: Report
System: The UNT Digital Library
Final Report for "Center for Technology for Advanced Scientific Component Software" (open access)

Final Report for "Center for Technology for Advanced Scientific Component Software"

The goal of the Center for Technology for Advanced Scientific Component Software is to fundamentally changing the way scientific software is developed and used by bringing component-based software development technologies to high-performance scientific and engineering computing. The role of Tech-X work in TASCS project is to provide an outreach to accelerator physics and fusion applications by introducing TASCS tools into applications, testing tools in the applications and modifying the tools to be more usable.
Date: December 1, 2010
Creator: Shasharina, Svetlana
Object Type: Report
System: The UNT Digital Library
Standard Problems for CFD Validation for NGNP - Status Report (open access)

Standard Problems for CFD Validation for NGNP - Status Report

The U.S. Department of Energy (DOE) is conducting research and development to support the resurgence of nuclear power in the United States for both electrical power generation and production of process heat required for industrial processes such as the manufacture of hydrogen for use as a fuel in automobiles. The project is called the Next Generation Nuclear Plant (NGNP) Project, which is based on a Generation IV reactor concept called the very high temperature reactor (VHTR). The VHTR will be of the prismatic or pebble bed type; the former is considered herein. The VHTR will use helium as the coolant at temperatures ranging from 250°C to perhaps 1000°C. While computational fluid dynamics (CFD) has not previously been used for the safety analysis of nuclear reactors in the United States, it is being considered for existing and future reactors. It is fully recognized that CFD simulation codes will have to be validated for flow physics reasonably close to actual fluid dynamic conditions expected in normal operational and accident situations. The “Standard Problem” is an experimental data set that represents an important physical phenomenon or phenomena, whose selection is based on a phenomena identification and ranking table (PIRT) for the reactor in …
Date: August 1, 2010
Creator: Johnson, Richard W. & Schultz, Richard R.
Object Type: Report
System: The UNT Digital Library
On a theory of neutrino oscillations with entanglement (open access)

On a theory of neutrino oscillations with entanglement

We show that the standard expression for the neutrino oscillation length can be confirmed even in theoretical approaches that take into account entanglement between the neutrino and its interaction partners. We show this in particular for the formalism developed in arXiv:1004.1847. Finally, we shed some light on the question why plane-wave approaches to the neutrino oscillation problem can yield the correct result for the oscillation length even though they do not explicitly account for the localization of the neutrino source and the detector.
Date: June 1, 2010
Creator: Kayser, Boris; Kopp, Joachim; Roberston, R. G. Hamish & Vogel, Petr
Object Type: Article
System: The UNT Digital Library
Advanced Reflector and Absorber Materials (Fact Sheet) (open access)

Advanced Reflector and Absorber Materials (Fact Sheet)

Fact sheet describing NREL CSP Program capabilities in the area of advanced reflector and absorber materials: evaluating performance, determining degradation rates and lifetime, and developing new coatings.
Date: August 1, 2010
Creator: unknown
Object Type: Report
System: The UNT Digital Library
The SEMATECH Berkeley MET pushing EUV development beyond 22-nm half pitch (open access)

The SEMATECH Berkeley MET pushing EUV development beyond 22-nm half pitch

Microfield exposure tools (METs) play a crucial role in the development of extreme ultraviolet (EUV) resists and masks, One of these tools is the SEMATECH Berkeley 0.3 numerical aperture (NA) MET, Using conventional illumination this tool is limited to approximately 22-nm half pitch resolution. However, resolution enhancement techniques have been used to push the patterning capabilities of this tool to half pitches of 18 nm and below, This resolution was achieved in a new imageable hard mask which also supports contact printing down to 22 nm with conventional illumination. Along with resolution, line-edge roughness is another crucial hurdle facing EUV resists, Much of the resist LER, however, can be attributed to the mask. We have shown that intenssionally aggressive mask cleaning on an older generation mask causes correlated LER in photoresist to increase from 3.4 nm to 4,0 nm, We have also shown that new generation EUV masks (100 pm of substrate roughness) can achieve correlated LER values of 1.1 nm, a 3x improvement over the correlated LER of older generation EUV masks (230 pm of substrate roughness), Finally, a 0.5-NA MET has been proposed that will address the needs of EUV development at the 16-nm node and beyond, The …
Date: March 18, 2010
Creator: Naulleau, P.; Anderson, C. N.; Backlea-an, L.-M.; Chan, D.; Denham, P.; George, S. et al.
Object Type: Article
System: The UNT Digital Library
Post-Closure Inspection Report for the Tonopah Test Range, Nevada, for Calendar Year 2009 (open access)

Post-Closure Inspection Report for the Tonopah Test Range, Nevada, for Calendar Year 2009

This report provides the results of the annual post-closure inspections conducted at the closed Corrective Action Unit (CAU) sites located on the Tonopah Test Range (TTR), Nevada. This report covers calendar year 2009 and includes inspection and repair activities completed at the following seven CAUs: · CAU 400: Bomblet Pit and Five Points Landfill (TTR) · CAU 407: Roller Coaster RadSafe Area (TTR) · CAU 424: Area 3 Landfill Complexes (TTR) · CAU 426: Cactus Spring Waste Trenches (TTR) · CAU 453: Area 9 UXO Landfill (TTR) · CAU 484: Surface Debris, Waste Sites, and Burn Area (TTR) · CAU 487: Thunderwell Site (TTR) The annual post-closure inspections were conducted May 5–6, 2009. All inspections were conducted according to the post-closure plans in the approved Closure Reports. The post-closure inspection plan for each CAU is included in Attachment B, with the exception of CAU 400. CAU 400 does not require post-closure inspections, but inspections of the vegetation and fencing are conducted as a best management practice. The inspection checklists for each site inspection are included in Attachment C, the field notes are included in Attachment D, and the site photographs are included in Attachment E. Vegetation monitoring of CAU 400, …
Date: May 28, 2010
Creator: National Security Technologies, LLC
Object Type: Report
System: The UNT Digital Library
Computational and Experimental Development of Novel High Temperature Alloys (open access)

Computational and Experimental Development of Novel High Temperature Alloys

The work done in this paper is based on our earlier work on developing an extended Miedema model and then using it to downselect potential alloy systems. Our approach is to closely couple the semi-empirical methodologies to more accurate ab initio methods to dentify the best candidates for ternary alloying additions. The architectural framework for our material's design is a refractory base metal with a high temperature intermetallic which provides both high temperature creep strength and a source of oxidatively stable elements. Potential refractory base metals are groups IIIA, IVA and VA. For Fossil applications, Ni-Al appears to be the best choice to provide the source of oxidatively stable elements but this system requires a 'boost' in melting temperatures to be a viable candidate in the ultra-high temperature regime (> 1200C). Some late transition metals and noble elements are known to increase the melting temperature of Ni-Al phases. Such an approach suggested that a Mo-Ni-Al system would be a good base alloy system that could be further improved upon by dding Platinum group metals (PGMs). In this paper, we demonstrate the variety of microstructures that can be synthesized for the base alloy system, its oxidation behavior as well as the …
Date: June 29, 2010
Creator: Kramer, M. J.; Ray, P. K. & Akinc, M.
Object Type: Report
System: The UNT Digital Library
Modular Coils and Plasma Configurations for Quasi-axisymmetric Stellarators (open access)

Modular Coils and Plasma Configurations for Quasi-axisymmetric Stellarators

Characteristics of modular coils for quasi-axisymmetric stellarators that are related to the plasma aspect ratio, number of field periods and rotational transform have been examined systematically. It is observed that, for a given plasma aspect ratio, the coil complexity tends to increase with the increased number of field periods. For a given number of field periods, the toroidal excursion of coil winding is reduced as the plasma aspect ratio is increased. It is also clear that the larger the coil-plasma separation is, the more complex the coils become. It is further demonstrated that it is possible to use other types of coils to complement modular coils to improve both the physics and the modular coil characteristics.
Date: September 10, 2010
Creator: Ku, L. P. & Boozer, A. H.
Object Type: Report
System: The UNT Digital Library
Kinetics of Fe(II)-catalyzed transformation of 6-line ferrihydrite under anaerobic flow conditions (open access)

Kinetics of Fe(II)-catalyzed transformation of 6-line ferrihydrite under anaerobic flow conditions

The readsorption of ferrous ions produced by the abiotic and microbially-mediated reductive dissolution of iron oxy-hydroxides drives a series of transformations of the host minerals. To further understand the mechanisms by which these transformations occur and their kinetics within a microporous flow environment, flow-through experiments were conducted in which capillary tubes packed with ferrihydrite-coated glass spheres were injected with inorganic Fe(II) solutions under circumneutral pH conditions at 25 C. Synchrotron X-ray diffraction was used to identify the secondary phase(s) formed and to provide data for quantitative kinetic analysis. At concentrations at and above 1.8 mM Fe(II) in the injection solution, magnetite was the only secondary phase formed (no intermediates were detected), with complete transformation following a nonlinear rate law requiring 28 hours and 150 hours of reaction at 18 and 1.8 mM Fe(II), respectively. However, when the injection solution consisted of 0.36 mM Fe(II), goethite was the predominant reaction product and formed much more slowly according to a linear rate law, while only minor magnetite was formed. When the rates are normalized based on the time to react half of the ferrihydrite on a reduced time plot, it is apparent that the 1.8 mM and 18 mM input Fe(II) experiments …
Date: April 1, 2010
Creator: Yang, L.; Steefel, C. I.; Marcus, M. A. & Bargar, J. R.
Object Type: Article
System: The UNT Digital Library
Improving the Material Response for Slow Heat of Energetic Materials (open access)

Improving the Material Response for Slow Heat of Energetic Materials

The goal of modern high explosive slow heat cookoff modeling is to understand the level of mechanical violence. This requires understanding the coupled thermal-mechanical-chemical system that such an environment creates. Recent advances have improved our ability to predict the time to event, and we have been making progress on predicting the mechanical response. By adding surface tension to the product gas pores in the high explosive, we have been able to reduce the current model's tendency to overpressurize confinement vessels. We describe the model and demonstrate how it affects a LX-10 STEX experiment. Issues associated with current product gas equations of state are described and examined.
Date: March 8, 2010
Creator: Nichols, A. L.
Object Type: Article
System: The UNT Digital Library
Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1–June 30, 2010 (open access)

Atmospheric Radiation Measurement Program Climate Research Facility Operations Quarterly Report April 1–June 30, 2010

Individual raw datastreams from instrumentation at the Atmospheric Radiation Measurement (ARM) Climate Research Facility fixed and mobile sites are collected and sent to the Data Management Facility (DMF) at Pacific Northwest National Laboratory (PNNL) for processing in near real-time. Raw and processed data are then sent approximately daily to the ARM Archive, where they are made available to users. For each instrument, we calculate the ratio of the actual number of data records received daily at the Archive to the expected number of data records. The results are tabulated by (1) individual datastream, site, and month for the current year and (2) site and fiscal year (FY) dating back to 1998.
Date: July 9, 2010
Creator: Sisterson, D. L.
Object Type: Report
System: The UNT Digital Library
The added economic and environmental value of plug-in electric vehicles connected to commercial building microgrids (open access)

The added economic and environmental value of plug-in electric vehicles connected to commercial building microgrids

Connection of electric storage technologies to smartgrids or microgrids will have substantial implications for building energy systems. In addition to potentially supplying ancillary services directly to the traditional centralized grid (or macrogrid), local storage will enable demand response. As an economically attractive option, mobile storage devices such as plug-in electric vehicles (EVs) are in direct competition with conventional stationary sources and storage at the building. In general, it is assumed that they can improve the financial as well as environmental attractiveness of renewable and fossil based on-site generation (e.g. PV, fuel cells, or microturbines operating with or without combined heat and power). Also, mobile storage can directly contribute to tariff driven demand response in commercial buildings. In order to examine the impact of mobile storage on building energy costs and carbon dioxide (CO2) emissions, a microgrid/distributed-energy-resources (DER) adoption problem is formulated as a mixed-integer linear program with minimization of annual building energy costs applying CO2 taxes/CO2 pricing schemes. The problem is solved for a representative office building in the San Francisco Bay Area in 2020. By using employees' EVs for energy management, the office building can arbitrage its costs. But since the car battery lifetime is reduced, a business model …
Date: August 25, 2010
Creator: Stadler, Michael; Momber, Ilan; Megel, Olivier; Gomez, Tomás; Marnay, Chris; Beer, Sebastian et al.
Object Type: Article
System: The UNT Digital Library
Steps toward fault-tolerant quantum chemistry. (open access)

Steps toward fault-tolerant quantum chemistry.

Developing quantum chemistry programs on the coming generation of exascale computers will be a difficult task. The programs will need to be fault-tolerant and minimize the use of global operations. This work explores the use a task-based model that uses a data-centric approach to allocate work to different processes as it applies to quantum chemistry. After introducing the key problems that appear when trying to parallelize a complicated quantum chemistry method such as coupled-cluster theory, we discuss the implications of that model as it pertains to the computational kernel of a coupled-cluster program - matrix multiplication. Also, we discuss the extensions that would required to build a full coupled-cluster program using the task-based model. Current programming models for high-performance computing are fault-intolerant and use global operations. Those properties are unsustainable as computers scale to millions of CPUs; instead one must recognize that these systems will be hierarchical in structure, prone to constant faults, and global operations will be infeasible. The FAST-OS HARE project is introducing a scale-free computing model to address these issues. This model is hierarchical and fault-tolerant by design, allows for the clean overlap of computation and communication, reducing the network load, does not require checkpointing, and avoids …
Date: May 1, 2010
Creator: Taube, Andrew Garvin
Object Type: Report
System: The UNT Digital Library
Limits on superconductivity-related magnetization in Sr 2RuO 4 and PrOs 4Sb 12 from scanning SQUID microscopy (open access)

Limits on superconductivity-related magnetization in Sr 2RuO 4 and PrOs 4Sb 12 from scanning SQUID microscopy

We present scanning SQUID microscopy data on the superconductors Sr{sub 2}RuO{sub 4} (T{sub c} = 1.5 K) and PrOs{sub 4}Sb{sub 12} (T{sub c} = 1.8 K). In both of these materials, superconductivity-related time-reversal symmetry-breaking fields have been observed by muon spin rotation; our aim was to visualize the structure of these fields. However in neither Sr{sub 2}RuO{sub 4} nor PrOs{sub 4}Sb{sub 12} do we observe spontaneous superconductivity-related magnetization. In Sr{sub 2}RuO{sub 4}, many experimental results have been interpreted on the basis of a p{sub x} {+-} ip{sub y} superconducting order parameter. This order parameter is expected to give spontaneous magnetic induction at sample edges and order parameter domain walls. Supposing large domains, our data restrict domain wall and edge fields to no more than {approx}0.1% and {approx}0.2% of the expected magnitude, respectively. Alternatively, if the magnetization is of the expected order, the typical domain size is limited to {approx}30 nm for random domains, or {approx} 500 nm for periodic domains.
Date: August 26, 2010
Creator: Moler, Kathryn
Object Type: Article
System: The UNT Digital Library
Advancing Clean Energy Technology (Fact Sheet) (open access)

Advancing Clean Energy Technology (Fact Sheet)

DOE/EERE Solar Energy Technologies Program Fact Sheet - Advancing Clean Energy Technology, May 2010.
Date: July 1, 2010
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Fiber Accelerating Structures (open access)

Fiber Accelerating Structures

One of the options for future particle accelerators are photonic band gap (PBG) fiber accelerators. PBG fibers are specially designed optical fibers that use lasers to excite an electric field that is used to accelerate electrons. To improve PBG accelerators, the basic parameters of the fiber were tested to maximize defect size and acceleration. Using the program CUDOS, several accelerating modes were found that maximized these parameters for several wavelengths. The design of multiple defects, similar to having closely bound fibers, was studied to find possible coupling or the change of modes. The amount of coupling was found to be dependent on distance separated. For certain distances accelerating coupled modes were found and examined. In addition, several non-periodic fiber structures were examined using CUDOS. The non-periodic fibers produced several interesting results and promised more modes given time to study them in more detail.
Date: August 25, 2010
Creator: Hammond, Andrew P. & /SLAC, /Reed Coll.
Object Type: Report
System: The UNT Digital Library
Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter (open access)

Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuzmin energy threshold, 6 x 10{sup 19} eV. The anisotropy was measured by the fraction of arrival directions that are less than 3.1{sup o} from the position of an active galactic nucleus within 75 Mpc (using the Veron-Cetty and Veron 12th catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is (38{sub -6}{sup +7})%, compared with 21% expected for isotropic cosmic rays. This is down from the early estimate of (69{sub -13}{sup +11})%. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function …
Date: June 1, 2010
Creator: Abreu, P.; /Lisbon, IST; Aglietta, M.; /Turin U. /INFN, Turin; Ahn, E.J.; /Fermilab et al.
Object Type: Article
System: The UNT Digital Library
Multivariate analysis of progressive thermal desorption coupled gas chromatography-mass spectrometry. (open access)

Multivariate analysis of progressive thermal desorption coupled gas chromatography-mass spectrometry.

Thermal decomposition of poly dimethyl siloxane compounds, Sylgard{reg_sign} 184 and 186, were examined using thermal desorption coupled gas chromatography-mass spectrometry (TD/GC-MS) and multivariate analysis. This work describes a method of producing multiway data using a stepped thermal desorption. The technique involves sequentially heating a sample of the material of interest with subsequent analysis in a commercial GC/MS system. The decomposition chromatograms were analyzed using multivariate analysis tools including principal component analysis (PCA), factor rotation employing the varimax criterion, and multivariate curve resolution. The results of the analysis show seven components related to offgassing of various fractions of siloxanes that vary as a function of temperature. Thermal desorption coupled with gas chromatography-mass spectrometry (TD/GC-MS) is a powerful analytical technique for analyzing chemical mixtures. It has great potential in numerous analytic areas including materials analysis, sports medicine, in the detection of designer drugs; and biological research for metabolomics. Data analysis is complicated, far from automated and can result in high false positive or false negative rates. We have demonstrated a step-wise TD/GC-MS technique that removes more volatile compounds from a sample before extracting the less volatile compounds. This creates an additional dimension of separation before the GC column, while simultaneously generating three-way …
Date: September 1, 2010
Creator: Van Benthem, Mark Hilary; Mowry, Curtis Dale; Kotula, Paul Gabriel & Borek, Theodore Thaddeus, III
Object Type: Report
System: The UNT Digital Library
Deuterium Retention in NSTX with Lithium Conditioning (open access)

Deuterium Retention in NSTX with Lithium Conditioning

High (≈ 90%) deuterium retention was observed in NSTX gas balance measurements both withand without lithiumization of the carbon plasma facing components. The gas retained in ohmic discharges was measured by comparing the vessel pressure rise after a discharge to that of a gasonly pulse with the pumping valves closed. For neutral beam heated discharges the gas input and gas pumped by the NB cryopanels were tracked. The discharges were followed by outgassing of deuterium that reduced the retention. The relationship between retention and surface chemistry was explored with a new plasma-material interface probe connected to an in-vacuo surface science station that exposed four material samples to the plasma. XPS and TDS analysis showed that the binding of D atoms is fundamentally changed by lithium - in particular atoms are weakly bonded in regions near lithium atoms bound to either oxygen or the carbon matrix.
Date: June 2, 2010
Creator: C.H. Skinner, J.P. Allain, W. Blanchard, H.W. Kugel, R. Maingi, L. Roquemore, V. Soukhanovskii, C.N. Taylor
Object Type: Article
System: The UNT Digital Library