Multi-fluid code simulations including anomalous non-diffusive transport of plasma and impurities in the tokamak SOL (open access)

Multi-fluid code simulations including anomalous non-diffusive transport of plasma and impurities in the tokamak SOL

Fast intermittent transport has been observed in the scrape-off layer (SOL) of major tokamaks including Alcator C-Mod, DIII-D, and NSTX. This kind of transport is not diffusive but rather convective. It strongly increases plasma flux to the chamber walls and enhances the recycling of neutral particles in the main chamber. We discuss anomalous cross-field convection (ACFC) model for impurity and main plasma ions and its relation to intermittent transport events, i.e. plasma density blobs and holes in the SOL. Along with plasma diffusivity coefficients, our transport model introduces time-independent anomalous cross-field convective velocity. In the discharge modelling, diffusivity coefficients and ACFC velocity profiles are adjusted to match a set of representative experimental data. We use this model in the edge plasma physics code UEDGE to simulate the multi-fluid two-dimensional transport for these three tokamaks. We present simulation results suggesting the dominance of anomalous convection in the far SOL transport. These results are consistent with the hypothesis that the chamber wall is an important source of impurities and that different impurity charge states have different directions of anomalous convective velocity.
Date: November 25, 2003
Creator: Pigarov, A. Yu; West, W. P.; Soukhanovskii, V.; Rognlien, T. D.; Maingi, R.; Lipschultz, B. et al.
Object Type: Article
System: The UNT Digital Library
Monitoring Plan for RCRA Groundwater Assessment at the 216-U-12 Crib, Interim Change Notice 1 (open access)

Monitoring Plan for RCRA Groundwater Assessment at the 216-U-12 Crib, Interim Change Notice 1

This ICN corrects a typing error that was identified for one of the wells listed in Tables 4.1 and 4.2 on page 4.3 of the original document.
Date: November 25, 2003
Creator: Williams, Bruce A.
Object Type: Report
System: The UNT Digital Library
Electrochemical Hydrogen Sensor for Safety Monitoring (open access)

Electrochemical Hydrogen Sensor for Safety Monitoring

A hydrogen safety sensor is presented which provides high sensitivity and fast response time when operated in air. The target application for the sensor is external deployment near systems using or producing high concentrations of hydrogen. The sensor is composed of a catalytically active metal-oxide sensing electrode and a noble metal reference electrode attached to an yttria-stabilized zirconia (YSZ) electrolyte. The sensing approach is based on the difference in oxidation rate of hydrogen on the different electrode materials. Results will be presented for a sensor using a sensing electrode of tin-doped indium oxide (ITO). Response to H{sub 2}, and cross-sensitivity to hydrocarbon and H{sub 2}O are discussed.
Date: April 25, 2003
Creator: Martin, L. P.; Pham, A. Q. & Glass, R. S.
Object Type: Article
System: The UNT Digital Library
Coherence Measurements of a Transient 14.7 nm X-ray Laser (open access)

Coherence Measurements of a Transient 14.7 nm X-ray Laser

We present the longitudinal coherence measurement of the transient inversion collisional x-ray laser for the first time. The Ni-like Pd x-ray laser at 14.68 nm is generated by the LLNL COMET laser facility and is operating in the gain-saturated regime. Interference fringes are produced using a Michelson interferometer setup in which a thin multilayer-coated membrane is used as a beam splitter. The longitudinal coherence length for the picosecond duration 4d{sup 1}S{sub 0} {yields} 4p{sup 1}P{sub 1} lasing transition is determined to be {approx}400 {micro}m (1/e HW) by adjusting the length of one interferometer arm and measuring the resultant variation in fringe visibility. This is four times improved coherence than previous measurements on quasi-steady state schemes largely as a result of the narrower line profile in the lower temperature plasma. The inferred gain-narrowed linewidth of {approx}0.29 pm is also substantially narrower than previous measurements on quasi-steady state x-ray laser schemes. This study shows that the coherence of the x-ray laser beam can be improved by changing the laser pumping conditions. The x-ray laser is operating at 4 - 5 times the transform-limited pulse.
Date: November 25, 2003
Creator: Remond, C; Dunn, J; Delmotte, F; Nilsen, J; Hubert, S; Ravet, M et al.
Object Type: Article
System: The UNT Digital Library
Microsecond Microfluidic Mixing for Investigation of Protein Folding Kinetics (open access)

Microsecond Microfluidic Mixing for Investigation of Protein Folding Kinetics

We have developed and characterized a mixer to study the reaction kinetics of protein folding on a microsecond timescale. The mixer uses hydrodynamic focusing of pressure-driven flow in a microfluidic channel to reduce diffusion times as first demonstrated by Knight et al.[1]. Features of the mixer include 1 {micro}s mixing times, sample consumptions of order 1 nl/s, loading sample volumes on the order of microliters, and the ability to manufacture in fused silica for compatibility with most spectroscopic methods.
Date: June 25, 2003
Creator: Hertzog, D E; Santiago, J G & Bakajin, O
Object Type: Article
System: The UNT Digital Library
Data Package for Groundwater Monitoring Well 299-W15-43 at the 200-ZP-1 Operable Unit (open access)

Data Package for Groundwater Monitoring Well 299-W15-43 at the 200-ZP-1 Operable Unit

One new groundwater monitoring well was constructed at the 200-ZP-1 Operable Unit in November 2002. This document provides the information on drilling and construction of this well. One new groundwater monitoring well was constructed in the 200-ZP-1 Operable Unit in November 2002. The purpose of the well is to monitor carbon tetrachloride concentrations in response to the 200-ZP-1 carbon tetrachloride pump-and-treat operations. The well name is 299-W15-43 and the corresponding well number is C3955. Well 299-W15-43 is located about 8 meters west of the 216-T-25 trench. The location of the well is shown on Figure 1. Well 299-W15-43 was drilled in response to the recommendations of a Data Quality Objectives process that indicated a need for additional monitoring wells in the area (BHI-01576). The new well was constructed to the specifications and requirements described in Washington Administrative Code (WAC) 173-160 and WAC 173-303, the Data Quality Objectives document (BHI-01576), and the description of work for well drilling and construction. This document compiles information on the drilling and construction, geophysical logging, and sediment and groundwater sampling applicable to the installation of well 299-W15-43. The information on drilling and construction, well development, and pump installation is summarized from CP-14265. Appendix A contains …
Date: April 25, 2003
Creator: Horton, Duane G.
Object Type: Report
System: The UNT Digital Library
Charged Higgs bosons in the transition region M{sub H{sup {+-}}} {approx} m{sub t} at the LHC (open access)

Charged Higgs bosons in the transition region M{sub H{sup {+-}}} {approx} m{sub t} at the LHC

We illustrate preliminary results obtained through Monte Carlo (HERWIG) and detector (ATLFAST) simulations of the H{sup {+-}} {yields} {tau}{sup {+-}}{nu}{sub {tau}} signature of charged Higgs bosons with masses comparable to that of the top quark.
Date: May 25, 2003
Creator: ASSAMAGAN,K. A. GUCHAIT,M. MORETTI,S.
Object Type: Article
System: The UNT Digital Library
V-1 TRANSITION AND N-VALUE OF MULTIFILAMENTARY LTS AND HTS WIRES AND CABLES. (open access)

V-1 TRANSITION AND N-VALUE OF MULTIFILAMENTARY LTS AND HTS WIRES AND CABLES.

For low T, multifilamentary conductors like NbTi and Nb{sub 3}Sn, the V-I transition to the normal state is typically quantified by the parameter, n, defined by ({rho}/{rho}{sub c})= (I/I{sub c}){sup n}. For NbTi, this parameterization has been very useful in the development of high Jc wires, where the n-value is regarded as an index of the filament quality. In copper-matrix wires with undistorted filaments, the n-value at 5T is {approx} 40-60, and drops monotonically with increasing field. However, n can vary significantly in conductors with higher resistivity matrices and those with a low copper fraction. Usually high n-values are associated with unstable resistive behavior and premature quenching. The n-value in NbTi Rutherford cables, when compared to that in the wires is useful in evaluating cabling degradation of the critical current due to compaction at the edges of the cable. In Nb{sub 3}Sn wires, n-value has been a less useful tool, since often the resistive transition shows small voltages {approx} a few {mu}V prior to quenching. However, in ''well behaved'' wires, n is {approx} 30-40 at 12T and also shows a monotonic behavior with field. Strain induced I{sub c} degradation in these wires is usually associated with lower n-values. For high …
Date: May 25, 2003
Creator: GHOSH,A. K.
Object Type: Article
System: The UNT Digital Library
Cold Dissolved Saltcake Waste Simulant Development, Preparation, and Analysis (open access)

Cold Dissolved Saltcake Waste Simulant Development, Preparation, and Analysis

CH2M Hill Hanford Group, Inc. is identifying and developing supplemental process technologies to accelerate the Hanford tank waste cleanup mission. Bulk vitrification, containerized grout, and steam reforming are three technologies under consideration for treatment of the radioactive saltcake wastes in 68 single-shell tanks. To support development and testing of these technologies, Pacific Northwest National Laboratory (PNNL) was tasked with developing a cold dissolved saltcake simulant formulation to be representative of an actual saltcake waste stream, preparing a 25-L batch of the simulant, and analyzing the composition of the batch to assure conformance to formulation targets. Lacking a defined composition for dissolved actual saltcake waste, PNNL used available tank waste composition information and an equilibrium chemistry model (Environmental Simulation Program, ESP) to predict the concentrations of analytes in solution. Observations of insoluble solids in initial laboratory preparations for the model predicted formulation prompted minor modifications in the concentration of phosphate and silicon in the final simulant formulation. The analytical results for the 25-L simulant batch agree within the expected measurement accuracy (~10%) of the target concentrations and are highly consistent for replicate measurements, with a few minor exceptions. The instrumental analyses indicate that the batch of solution adequately reflects the as-formulated …
Date: February 25, 2003
Creator: Rassat, Scot D.; Mahoney, Lenna A.; Russell, Renee L.; Bryan, Samuel A. & Sell, Rachel L.
Object Type: Report
System: The UNT Digital Library
Ergonomics for Children and Educational Environments - Around the World (open access)

Ergonomics for Children and Educational Environments - Around the World

This paper briefly reviews activities and research related to children and educational environments. The increasing prevalence and role of information and communications technology in the lives of children as well as the incidence of back pain and heavy loads children carry in back packs are raising concerns around the world. Out of this concern an International Ergonomics Association Technical Committee has been formed. A survey was sent to Ergonomics for Children and Educational Environments membership and those who have communicated through the committee. The results are compiled to describe a cross-section of international efforts to address the health and the future of children.
Date: June 25, 2003
Creator: Bennett, C L & Tien, D
Object Type: Article
System: The UNT Digital Library
Application of Prompt Gamma-Ray Analysis to Identify Electrorefining Salt-Bearing Plutonium Oxide at the Plutonium Finishing Plant (open access)

Application of Prompt Gamma-Ray Analysis to Identify Electrorefining Salt-Bearing Plutonium Oxide at the Plutonium Finishing Plant

Prompt gamma-ray analysis is being implemented at the Plutonium Finishing Plant (PFP) to screen impure plutonium oxide inventory items, received in the mid-1980s from the Rocky Flats Plant, for the presence of sodium chloride and potassium chloride salts from the electrorefining process. A large fraction of these items are suspected to contain electrorefining salts. Because the salts evaporate at the=950C stabilization temperature mandated for long-term storage under the U.S. Department of Energy plutonium oxide stabilization and storage criteria to plug and corrode process equipment, items found to have these salts qualify for thermal stabilization at 750C. The prompt gamma ray energies characteristic of sodium, potassium, chlorine, and other low atomic weight elements arise from the interaction the light elements with alpha radiation from plutonium and americium radioactive decay. High-resolution gamma ray spectrometers designed to detect energies up to {approx}4.5 MeV are used to gather the high-energy prompt gamma spectra.Observation of the presence of the high-energy gamma peaks representing the natural chlorine-35, sodium-23, and potassium-39 isotopes and the sodium-to-chlorine peak area ratios in the range for plutonium oxide materials known to contain the electrorefining salts give the evidence needed to identify plutonium oxide materials at the PFP that qualify for the …
Date: September 25, 2003
Creator: Fazzari, Dennis M. (FLUOR HANFORD, INC); Jones, Susan A. (FLUOR HANFORD, INC) & Delegard, Calvin H. (BATTELLE (PACIFIC NW LAB))
Object Type: Report
System: The UNT Digital Library
Possible Incorporation of Neptunium in Uranyl (VI) Alteration Phases (open access)

Possible Incorporation of Neptunium in Uranyl (VI) Alteration Phases

This study examines existing data on Np behavior from both spent fuel and borosilicate glass tests in effort to resolve issues concerning the selection of possible solubility limiting phases for neptunium and the methods for detecting neptunium at low levels in spent fuel. These issues were raised in a recent report by Finch and Fortner (2002) that argues that the Np analysis with Electron Energy-Loss Spectroscopy (EELS) reported by Buck et al., (1998) is incorrect and that based on a series of experiments with Np-doped U3O8, NpO2 should be adopted as the solubility controlling phase for Np, in the Yucca Mountain performance assessment model. In this report, we will refute the claim that EELS is unable to detect Np and will suggest that the use of NpO2 as the Np solubility controlling phase is not supported by available scientific data from both spent fuel and borosilicate glass.
Date: November 25, 2003
Creator: Buck, Edgar C.; McNamara, Bruce K.; Douglas, Matthew & Hanson, Brady D.
Object Type: Report
System: The UNT Digital Library
IN SITU PRECISE ANGLE MONITORING ON SYNCHROTRON RADIATION MONOCHROMATOR BY USE OF PENCIL BEAM INTERFEROMETER. (open access)

IN SITU PRECISE ANGLE MONITORING ON SYNCHROTRON RADIATION MONOCHROMATOR BY USE OF PENCIL BEAM INTERFEROMETER.

Monochromator is a very important and precise instrument used in beam lines at synchrotron radiation facilities. We need to know if there is actual thermal distortion on gratings resulting in the degradation of the monochromator resolution. We need to know the characteristics of the grating rotation. It is possible to make a simple but precise in-situ distortion monitoring and rotation angle test of the grating by use of a precise pencil beam angle monitor. We have made preliminary measurements on a monochrometer grating of an undulator beam line X1B at Brookhaven National Laboratory. We monitored a small amount of angle variation on the grating. We detected 1.7 {micro}rad backlash (P-V) of the grating controlling system.
Date: August 25, 2003
Creator: QIAN,S. TAKACS,P. DONG,Q. HULBERT,S.
Object Type: Article
System: The UNT Digital Library
Full-Scale Cookoff Model Validation Experiments (open access)

Full-Scale Cookoff Model Validation Experiments

This paper presents the experimental results of the third and final phase of a cookoff model validation effort. In this phase of the work, two generic Heavy Wall Penetrators (HWP) were tested in two heating orientations. Temperature and strain gage data were collected over the entire test period. Predictions for time and temperature of reaction were made prior to release of the live data. Predictions were comparable to the measured values and were highly dependent on the established boundary conditions. Both HWP tests failed at a weld located near the aft closure of the device. More than 90 percent of unreacted explosive was recovered in the end heated experiment and less than 30 percent recovered in the side heated test.
Date: November 25, 2003
Creator: McClelland, M. A.; Rattanapote, M. K.; Heimdahl, E. R.; Erikson, W. E.; Curran, P. O. & Atwood, A. I.
Object Type: Article
System: The UNT Digital Library
Clean Reliable Water for the 21st Century (Paper#69880) (open access)

Clean Reliable Water for the 21st Century (Paper#69880)

It is well recognized that half the countries in the world will face significant fresh water shortages in the next 20 years, due largely to growing populations and increased agricultural and industrial demands. These shortages will significantly limit economic growth, decrease the quality of life and human health for billions of people, and could potentially lead to violence and conflict over securing scarce supplies of water. These concerns are not limited to the water-poor countries, of course, as many parts of China and the US face similar problems. Such problems can be exacerbated by fluctuating imbalances between need and supply, poor management practices, and pollution. The future is one that will require significant scientific and technological advances in conservation, preservation, and movement of fresh water, as well as in the development of new or alternative supplies. As an example, these issues are discussed in terms of California, and a case study related to the scientific issues associated with a groundwater banking project in Southern California is provided.
Date: February 25, 2003
Creator: Tompson, A. F. B.; Hudson, G. B. & Maxwell, R. M.
Object Type: Article
System: The UNT Digital Library
Groundwater Monitoring Plan for the 216-S-10 Pond and Ditch, Interim Change Notice 1 (open access)

Groundwater Monitoring Plan for the 216-S-10 Pond and Ditch, Interim Change Notice 1

During 2003, the upgradient well 299-W26-7 went dry and one new groundwater monitoring well was installed downgradient (well 299-W26-14) of the 216-S-10 pond and ditch. This ICN updates the groundwater monitoring wells for the 216-S-10 pond and ditch and adds a revised well location map to the plan.
Date: November 25, 2003
Creator: Williams, Bruce A.
Object Type: Report
System: The UNT Digital Library
Candidate Reagents for Dissolution of Hanford Site Tank Sludges-Scoping Studies with Simulants Using Single Reagents and Their Mixtures (open access)

Candidate Reagents for Dissolution of Hanford Site Tank Sludges-Scoping Studies with Simulants Using Single Reagents and Their Mixtures

Chemical agents were investigated for their efficacies in dissolving metal compound phases known to be present in Hanford tank waste sludges. The phases included Fe(OH)3, Cr(OH)3, Al(OH)3, MnO2, and Na2U2O7. In conjunction with laboratory testing, a survey of the technical literature also was performed to identify candidate reagents. The tests were conducted in three campaigns. First, scoping tests investigated individual agents identified in the literature review along with other candidate agents. Based on the scoping test results, follow-up testing was performed to investigate the efficacies of mixed citric/oxalic acids (CITROX) and mixed nitric/oxalic acids (NITROX). Overall, oxalic acid is the most effective single reagent, dissolving all of the solid phases to some extent. However, for MnO2 and Na2U2O7, reprecipitation soon followed dissolution. The MnO2 also oxidized at least two of organic acids tested, oxalic acid and citric acid, as shown by the evolution of gas during the tests with these reagents. The CITROX and NITROX tests failed to show beneficial synergistic effects in dissolving sludge phases. Instead, the findings suggest that the sequential addition of individual pure reagents (e.g., first citric acid to dissolve MnO2 and Na2U2O7 and removal of the solution followed by oxalic acid to dissolve the Fe, …
Date: August 25, 2003
Creator: Sinkov, Serguei I.
Object Type: Report
System: The UNT Digital Library
Actinide Measurements by Accelerator Mass Spectrometry at Lawrence Livermore National Laboratory (open access)

Actinide Measurements by Accelerator Mass Spectrometry at Lawrence Livermore National Laboratory

We report on the development of an accelerator mass spectrometry (AMS) system for the measurement of actinides at Lawrence Livermore National Laboratory. This AMS system is centered on a recently completed heavy isotope beam line that was designed particularly for high sensitivity, robust, high-throughput measurements of actinide concentrations and isotopic ratios. A fast isotope switching capability has been incorporated in the system, allowing flexibility in isotope selection and for the quasi-continuous normalization to a reference isotope spike. Initially, our utilization of the heavy isotope system has concentrated on the measurement of Pu isotopes. Under current operating conditions, background levels equivalent to {approx}1 x 10{sup 5} atoms are observed during routine {sup 239}Pu and {sup 240}Pu measurements. Measurements of samples containing {approx}10{sup 13} {sup 238}U atoms demonstrate that the system provides a {sup 238}U rejection factor during {sup 239}Pu measurements of {approx}10{sup 7}. Measurements of known materials, combined with results from an externally organized inter-comparison program, indicate that our {sup 239}Pu measurements are accurate and precise down to the {micro}Bq level ({approx}10{sup 6} atoms). Recently, we have investigated the performance of our heavy isotope AMS system in measurements of {sup 237}Np and {sup 236}U. Results of these investigations are discussed. The …
Date: September 25, 2003
Creator: Brown, T A; Marchetti, A A; Martinelli, R E; Cox, C C; Knezovich, J P & Hamilton, T F
Object Type: Article
System: The UNT Digital Library
Simulation of Time-Reversal Processing for Electromagnetic Communication (open access)

Simulation of Time-Reversal Processing for Electromagnetic Communication

Time-reversal processing was simulated for several possible electromagnetic communication channels, including random point scatterers, large plates and a conducting cavity. Communication was from a single transmitting antenna to a receiving array. The effectiveness of time-reversal processing was compared for a single receiver and the array. The aim of these simulations was to determine a communication environment that would give an interesting level of multipath interference and that can be constructed in a laboratory.
Date: July 25, 2003
Creator: Burke, G J & Poggio, A J
Object Type: Report
System: The UNT Digital Library
Physical Property and Rheological Testing of Actual Transuranic Waste from Hanford Single-Shell Tanks (open access)

Physical Property and Rheological Testing of Actual Transuranic Waste from Hanford Single-Shell Tanks

Composites of sludge from Hanford tanks 241-B-203 (B-203), 241-T-203 (T-203), 241-T-204 (T-204), and 241-T-110 (T-110) were prepared at the Hanford 222-S Laboratory and transferred to the Radiochemical Processing Laboratory at the Pacific Northwest National Laboratory (PNNL) for measurement of the composites' physical properties. These tank composites were prepared from core samples retieved from these tanks. These core samples may not be representative of the entire contents of the tank but provide some indication of the properties of the waste in these underground storage tanks. Dilutions in water were prepared from the composite samples. The measurements included paint filter tests, viscosity, shear strength, settling and centrifuging behavior, a qualitative test of stickiness, total solids concentration, and extrusion tests to estimate shear strength.
Date: August 25, 2003
Creator: Tingey, Joel M.; Gao, Johnway; Delegard, Calvin H.; Bagaasen, Larry M. & Wells, Beric E.
Object Type: Report
System: The UNT Digital Library
Blanket Biological Review for General Maintenance Activities Within Active Burial Grounds, 200 East and 200 West Areas, ECR No.2003-200-035 (open access)

Blanket Biological Review for General Maintenance Activities Within Active Burial Grounds, 200 East and 200 West Areas, ECR No.2003-200-035

No plant and animal species protected under the ESA, candidates for such protection, or species listed by the Washington state government were observed in the vicinity of the proposed sites. Piper's daisy may still occur in some of the burial grounds (218-E-12, 218-E-10). This is a Washington State Sensitive plant species, and as such is a Level III resource under the Hanford Site Biological Resources Management Plan. Compensatory mitigation is appropriate for this species when adverse impacts cannot be avoided. The stalked-pod and crouching milkvetch, Watch List species, are relatively common throughout 200 West area, therefore even if the few individuals within the active burial grounds are disturbed, it is not likely that the overall local population will be adversely affected. The Watch List is the lowest level of listing for plant species of concern in the State of Washington. No adverse impacts to species or habitats of concern are expected to occur from routine maintenance within the active portions of the 218-W-4C, 218-W-4B, 218-W-3, 218-W-3A, and 218-W-5 burial grounds, as well as the portion of 218-E-12B currently used for storage of retired submarine reactor cores. The remaining portions of the 218-E-12B burial ground and the entire 218-E-10 burial ground …
Date: August 25, 2003
Creator: Sackschewsky, Michael R.
Object Type: Report
System: The UNT Digital Library
Dislocation Image Stresses at Free Surfaces by the Finite Element Method (open access)

Dislocation Image Stresses at Free Surfaces by the Finite Element Method

The finite element method has been routinely used to calculate the image stresses of dislocation segments. When these segments intersect with surfaces, the image stresses at the surfaces diverges singularly. At the presence of these singularities, both convergence and accuracy of using the finite element method need to be examined critically. This article addresses these issues with the aim toward the application of dislocation dynamics simulations in thin films.
Date: November 25, 2003
Creator: Cai, W; Bulatov, V; Tang, M & Xu, G
Object Type: Article
System: The UNT Digital Library
IN PLANE OPTICAL RESPONSE OF UNDERDOPED La{sub 2-x}(Ca,Sr){sub x}CaCu{sub 2}O{sub 6+D} SINGLE CRYSTALS : EVIDENCE FOR INTRINSIC INHOMOGENEITY. (open access)

IN PLANE OPTICAL RESPONSE OF UNDERDOPED La{sub 2-x}(Ca,Sr){sub x}CaCu{sub 2}O{sub 6+D} SINGLE CRYSTALS : EVIDENCE FOR INTRINSIC INHOMOGENEITY.

The in-plane optical properties of two crystals of the bilayer cuprate La{sub 2-x}(Ca,Sr){sub x}Ca,Sr){sub x}CaCu{sub 2}O{sub 6+{delta}}, one with excess Ca and x = 0.10 and the other with Sr and x = 0.15, were investigated over the frequency range of 45-25000 cm{sup -1}. A metallic response both in frequency and temperature was observed for Sr = 0.15 superconducting sample at low frequencies. Meanwhile, the sample also exhibits a prominent charge-transfer excitation at around 15000 cm{sup -1}. This observation, together with neutron experiments performed on the same sample showing diffuse, elastic antiferromagnetic scattering, indicate that the quasi-mobile carriers coexist at low temperature with static antiferromagnetic clusters. This coexistence indicates intrinsic spatial inhomogeneity.
Date: May 25, 2003
Creator: WANG,N. L. ZHENG,P. FENG,T. GU,G. D. HOMES,C. C. TRANQUADA,J. M. GAULIN,B. D. TIMUSK,T.
Object Type: Article
System: The UNT Digital Library
Simulation of Chamber Transport for Heavy-Ion-Fusion Drivers (open access)

Simulation of Chamber Transport for Heavy-Ion-Fusion Drivers

The heavy-ion fusion (HIF) community recently developed a power-plant design that meets the various requirements of accelerators, final focus, chamber transport, and targets. The point design is intended to minimize physics risk and is certainly not optimal for the cost of electricity. Recent chamber-transport simulations, however, indicate that changes in the beam ion species, the convergence angle, and the emittance might allow more-economical designs.
Date: September 25, 2003
Creator: Sharp, W. M.; Callahan, D. A.; Tabak, M.; Yu, S. S.; Peterson, P. F.; Rose, D. V. et al.
Object Type: Article
System: The UNT Digital Library