Leak Path Factor Evaluation: A MELCOR Application for Nonreactor Nuclear Facilities (open access)

Leak Path Factor Evaluation: A MELCOR Application for Nonreactor Nuclear Facilities

This paper presents a Leak Path Factor (LPF) analysis for a postulated fire accident on a building containing plutonium powder when the resulting outside release is partly through the ventilation/filtration system and partly through other pathways such as building access doorways. When analyzing an accident scenario involving the release of radioactive powders inside a building, various pathways for the release to the outside environment can exist. This study is presented to show how the multiple building leak path factors (combination of filtered and unfiltered releases) can be evaluated in an integrated manner to assess the magnitude of the source term to be used in the consequence analysis. The core of the analysis is to calculate the leak path factor, which represents the fraction of respirable radioactive powder that is made airborne that leaves the building through the various pathways. The computer code of choice for this determination is MELCOR1. The analysis results can be used for the transport and dispersion of powder material released to the atmosphere and to estimate the resulting dose that is received by the downwind receptors of interest. This work can be used as model for performing analyses for systems similar in nature where releases can …
Date: May 3, 2004
Creator: Polizzi, L. Mario
Object Type: Article
System: The UNT Digital Library
Titan's 2 micron Surface Albedo and Haze Optical Depth in 1996-2004 (open access)

Titan's 2 micron Surface Albedo and Haze Optical Depth in 1996-2004

We observed Titan in 1996-2004 with high-resolution 2 {micro}m speckle and adaptive optics imaging at the W.M. Keck Observatory. By observing in a 2 {micro}m broadband filter we obtain images that have contributions from both Titan's surface and atmosphere. We have modeled Titan's atmosphere using a plane-parallel radiative transfer code that has been corrected to agree with 3-D Monte Carlo predictions. We find that Titan's surface albedo ranges from {le} 0:02 in the darkest equatorial region of the trailing hemisphere to {approx_equal} 0:1 in the brightest areas of the leading hemisphere. Over the past quarter of a Saturnian year haze optical depth in Titan's Southern hemisphere has decreased substantially from a value of 0.48 in 1996 down to 0.18 in 2004, while the northern haze has been increasing over the past few years. As a result of these changes, in 2004 the North/South haze asymmetry at K' band has disappeared.
Date: May 4, 2004
Creator: Gibbard, S. G.; de Pater, I.; Macintosh, B. A.; Roe, H. G.; Max, C. E.; Young, E. F. et al.
Object Type: Article
System: The UNT Digital Library
DEVELOPMENT OF IMPROVED ANAEROBIC GROWTH OF BACILLUS MOJAVENSIS STRAIN JF-2 FOR THE PURPOSE OF IMPROVED ANAEROBIC BIOSURFACTANT PRODUCTION FOR ENHANCED OIL RECOVERY (open access)

DEVELOPMENT OF IMPROVED ANAEROBIC GROWTH OF BACILLUS MOJAVENSIS STRAIN JF-2 FOR THE PURPOSE OF IMPROVED ANAEROBIC BIOSURFACTANT PRODUCTION FOR ENHANCED OIL RECOVERY

Our work focuses on the use of microorganisms to recover petroleum hydrocarbons that remain entrapped after current recovery technologies reach their economic limit. Capillary forces between the hydrocarbon and aqueous phases are largely responsible for trapping the hydrocarbons in the pores of the rock and large reductions in the interfacial tension between the hydrocarbon and aqueous phases are needed for hydrocarbon mobilization (1-3, 10, 11). Microorganisms produce a variety of biosurfactants (4), several of which generate the ultra low interfacial tensions needed for hydrocarbon mobilization (4, 5, 8). In particular, the lipopeptide biosurfactant produced by Bacillus mojavensis strain JF-2 reduces the interfacial tension between hydrocarbon and aqueous phases to very low levels (<0.016 mN/m) (8) (9). B. mojavensis JF-2 grows under the environmental conditions found in many oil reservoirs, i. e., anaerobic, NaCl concentrations up to 80 g l{sup -1}, and temperatures up to 45 C (6, 7), making it ideally suited for in situ applications. However, anaerobic growth of B. mojavensis JF-2 was inconsistent and difficult to replicate, which limited its use for in situ applications. Our initial studies revealed that enzymatic digests, such as Proteose Peptone, were required for anaerobic growth of Bacillus mojavensis JF-2. Subsequent purification of …
Date: May 31, 2004
Creator: McInerney, M.J.; Folmsbee, M. & Nagle, D.
Object Type: Report
System: The UNT Digital Library
Development of Microorganisms With Improved Transport and Biosurfactant Activity for Enhanced Oil Recovery Annual Report (open access)

Development of Microorganisms With Improved Transport and Biosurfactant Activity for Enhanced Oil Recovery Annual Report

Diverse microorganisms were screened for biosurfactant production and anaerobic growth at elevated salt concentrations to obtain candidates most suitable for microbial oil recovery. Seventy percent of the 205 strains tested, mostly strains of Bacillus mojavensis, Bacillus subtilis, Bacillus licheniformis, and Bacillus sonorensis, produced biosurfactants aerobically and 41% of the strains had biosurfactant activity greater than Bacillus mojavensis JF-2, the current candidate for oil recovery. Biosurfactant activity varied with the percentage of the 3-hydroxy-tetradecanoate isomers in the fatty acid portion of the biosurfactant. Changing the medium composition by incorporation of different precursors of 3-hydroxy tetradecanoate increased the activity of biosurfactant. The surface tension and critical micelle concentration of 15 different, biosurfactant-producing Bacillus strains was determined individually and in combination with other biosurfactants. Some biosurfactant mixtures were found to have synergistic effect on surface tension (e.g. surface tension was lowered from 41 to 31 mN/m in some cases) while others had a synergistic effect on CMD-1 values. We compared the transport abilities of spores from three Bacillus strains using a model porous system to study spore recovery and transport. Sand-packed columns were used to select for spores or cells with the best transport abilities through brine-saturated sand. Spores of Bacillus mojavensis strains …
Date: May 31, 2004
Creator: McInerney, M.J.; Youssef, N.; Fincher, T.; Maudgalya, S. K.; Folmsbee, M. J.; Knapp, R. et al.
Object Type: Report
System: The UNT Digital Library
Development of Biosurfactant-Mediated Oil Recovery in Model Porous Systems and Computer Simulations of Biosurfactant-Mediated Oil Recovery (open access)

Development of Biosurfactant-Mediated Oil Recovery in Model Porous Systems and Computer Simulations of Biosurfactant-Mediated Oil Recovery

Current technology recovers only one-third to one-half of the oil that is originally present in an oil reservoir. Entrapment of petroleum hydrocarbons by capillary forces is a major factor that limits oil recovery (1, 3, 4). Hydrocarbon displacement can occur if interfacial tension (IFT) between the hydrocarbon and aqueous phases is reduced by several orders of magnitude. Microbially-produced biosurfactants may be an economical method to recover residual hydrocarbons since they are effective at low concentrations. Previously, we showed that substantial mobilization of residual hydrocarbon from a model porous system occurs at biosurfactant concentrations made naturally by B. mojavensis strain JF-1 if a polymer and 2,3-butanediol were present (2). In this report, we include data on oil recovery from Berea sandstone experiments along with our previous data from sand pack columns in order to relate biosurfactant concentration to the fraction of oil recovered. We also investigate the effect that the JF-2 biosurfactant has on interfacial tension (IFT). The presence of a co-surfactant, 2,3-butanediol, was shown to improve oil recoveries possibly by changing the optimal salinity concentration of the formulation. The JF-2 biosurfactant lowered IFT by nearly 2 orders of magnitude compared to typical values of 28-29 mN/m. Increasing the salinity increased …
Date: May 31, 2004
Creator: McInerney, M.J.; Maudgalya, S.K.; Knapp, R. & Folmsbee, M.
Object Type: Report
System: The UNT Digital Library
Factors Controlling In Situ Uranium and Technetium Bio-Reduction and Reoxidation at the NABIR Field Research Center (open access)

Factors Controlling In Situ Uranium and Technetium Bio-Reduction and Reoxidation at the NABIR Field Research Center

Summary of Recent Field Testing: Extensive in situ (in ground) field testing using the push-pull method has demonstrated that indigenous microorganisms in the shallow (< 8 m) aquifer in FRC Areas 1 and 2 are capable of coupling the oxidation/fermentation of injected ethanol, glucose, or acetate to the reduction of U(VI) and Tc(VII). Despite highly variable initial (prior to testing) contaminant concentrations (pH: 3.3-7.2; Nitrate: 0.1-140 mM; U(VI): 1-12 uM; Tc(VII): 200-15000 pM), sequential donor additions resulted in increased rates of microbial activity (Denitrification: 01.-4.0 mM/hr; sulfate reduction: 0- 0.03 mM/hr; U(VI) reduction: 10-4 to 10-3 uM/hr; Tc(VII) reduction: 4-150 pM/hr) in all wells tested. Tc(VII) reduction and denitrification proceeded concomitantly in all tests. U(VI) reduction was concomitant with Fe(II) production in Area 1 but little Fe(II) was detected under sulfate reducing conditions in Area 2. Reoxidation of U(IV) (precipitated in the vicinity of the wells during previous tests) but not Tc(IV) was observed when injected test solutions contained initial nitrate concentrations > {approx} 20 mM. Field data and laboratory studies suggest that U(IV) is likely oxidized by Fe(III) minerals produced by enzymatic Fe(II) oxidation or by Fe(II) oxidation by nitrite. U(IV) reoxidation rates (10-3 to 10-2 uM/hr) were somewhat …
Date: May 5, 2004
Creator: Istok, Jonathan; Krumholz, L; McKinley, J. & Gu, B.
Object Type: Report
System: The UNT Digital Library
Investigation of oil injection into brine for the Strategic Petroleum Reserve : hydrodynamics and mixing experiments with SPR liquids. (open access)

Investigation of oil injection into brine for the Strategic Petroleum Reserve : hydrodynamics and mixing experiments with SPR liquids.

An experimental program was conducted to study a proposed approach for oil reintroduction in the Strategic Petroleum Reserve (SPR). The goal was to assess whether useful oil is rendered unusable through formation of a stable oil-brine emulsion during reintroduction of degassed oil into the brine layer in storage caverns. An earlier report (O'Hern et al., 2003) documented the first stage of the program, in which simulant liquids were used to characterize the buoyant plume that is produced when a jet of crude oil is injected downward into brine. This report documents the final two test series. In the first, the plume hydrodynamics experiments were completed using SPR oil, brine, and sludge. In the second, oil reinjection into brine was run for approximately 6 hours, and sampling of oil, sludge, and brine was performed over the next 3 months so that the long-term effects of oil-sludge mixing could be assessed. For both series, the experiment consisted of a large transparent vessel that is a scale model of the proposed oil-injection process at the SPR. For the plume hydrodynamics experiments, an oil layer was floated on top of a brine layer in the first test series and on top of a sludge …
Date: May 1, 2004
Creator: Castaneda, Jaime N.; Cote, Raymond O.; Torczynski, John R. & O'Hern, Timothy John
Object Type: Report
System: The UNT Digital Library
Solving the three-body Coulomb breakup problem using exterior complex scaling (open access)

Solving the three-body Coulomb breakup problem using exterior complex scaling

Electron-impact ionization of the hydrogen atom is the prototypical three-body Coulomb breakup problem in quantum mechanics. The combination of subtle correlation effects and the difficult boundary conditions required to describe two electrons in the continuum have made this one of the outstanding challenges of atomic physics. A complete solution of this problem in the form of a ''reduction to computation'' of all aspects of the physics is given by the application of exterior complex scaling, a modern variant of the mathematical tool of analytic continuation of the electronic coordinates into the complex plane that was used historically to establish the formal analytic properties of the scattering matrix. This review first discusses the essential difficulties of the three-body Coulomb breakup problem in quantum mechanics. It then describes the formal basis of exterior complex scaling of electronic coordinates as well as the details of its numerical implementation using a variety of methods including finite difference, finite elements, discrete variable representations, and B-splines. Given these numerical implementations of exterior complex scaling, the scattering wave function can be generated with arbitrary accuracy on any finite volume in the space of electronic coordinates, but there remains the fundamental problem of extracting the breakup amplitudes from …
Date: May 17, 2004
Creator: McCurdy, C. W.; Baertschy, M. & Rescigno, T. N.
Object Type: Article
System: The UNT Digital Library
Development of Chemical Treatment Alternatives for Tetraphenylborate Destruction in Tank 48H (open access)

Development of Chemical Treatment Alternatives for Tetraphenylborate Destruction in Tank 48H

This study assessed chemical treatment options for decomposing the tetraphenylborate in High Level Waste (HLW) Tank 48H. Tank 48H, located at the Savannah River Site in Aiken, SC, contains approximately one million liters of HLW. The tetraphenylborate slurry represents legacy material from commissioning of an In Tank Precipitation process to separate radioactive cesium and actinides from the non radioactive chemicals. During early operations, the process encountered an unplanned chemical reaction that catalytically decomposed the excess tetraphenylborate producing benzene. Subsequent research indicated that personnel could not control the operations within the existing equipment to both meet the desired treatment rate for the waste and maintain the benzene concentration within allowable concentrations. Since then, the Department of Energy selected an alternate treatment process for handling high-level waste at the site. However, the site must destroy the tetraphenylborate before returning the tank to HLW service. The research focuses on identifying treatments to decompose tetraphenylborate to the maximum extent feasible, with a preference for decomposition methods that produce carbon dioxide rather than benzene. A number of experiments examined whether the use of oxidants, catalysts or acids proved effective in decomposing the tetraphenylborate. Additional experiments developed an understanding of the solid, liquid and gas decomposition …
Date: May 4, 2004
Creator: Lambert, Daniel P.
Object Type: Article
System: The UNT Digital Library
Gas Turbine Reheat Using in Situ Combustion: Final Report, Draft (open access)

Gas Turbine Reheat Using in Situ Combustion: Final Report, Draft

In situ reheat is an alternative to traditional gas turbine reheat design in which fuel is fed through airfoils rather than in a bulky discrete combustor separating HP and LP turbines. The goals are to achieve increased power output and/or efficiency without higher emissions. In this program the scientific basis for achieving burnout with low emissions has been explored. In Task 1, Blade Path Aerodynamics, design options were evaluated using CFD in terms of burnout, increase of power output, and possible hot streaking. It was concluded that Vane 1 injection in a conventional 4-stage turbine was preferred. Vane 2 injection after vane 1 injection was possible, but of marginal benefit. In Task 2, Combustion and Emissions, detailed chemical kinetics modeling, validated by Task 3, Sub-Scale Testing, experiments, resulted in the same conclusions, with the added conclusion that some increase in emissions was expected. In Task 4, Conceptual Design and Development Plan, Siemens Westinghouse power cycle analysis software was used to evaluate alternative in situ reheat design options. Only single stage reheat, via vane 1, was found to have merit, consistent with prior Tasks. Unifying the results of all the tasks, a conceptual design for single stage reheat utilizing 24 holes, …
Date: May 17, 2004
Creator: Bachovchin, D. M.; Lippert, T. E.; Newby, R. A. & Cizmas, P. G. A.
Object Type: Report
System: The UNT Digital Library
Corrective Action Investigation Plan for Corrective Action Unit 543: Liquid Disposal Units, Nevada Test Site, Nevada: Revision 0 (open access)

Corrective Action Investigation Plan for Corrective Action Unit 543: Liquid Disposal Units, Nevada Test Site, Nevada: Revision 0

The general purpose of this Corrective Action Investigation Plan is to ensure that adequate data are collected to provide sufficient and reliable information to identify, evaluate, and select technically viable corrective action alternatives (CAAs) for Corrective Action Unit (CAU) 543: Liquid Disposal Units, Nevada Test Site (NTS), Nevada. Located in Areas 6 and 15 on the NTS, CAU 543 is comprised of a total of seven corrective action sites (CASs), one in Area 6 and six in Area 15. The CAS in Area 6 consists of a Decontamination Facility and its components which are associated with decontamination of equipment, vehicles, and materials related to nuclear testing. The six CASs in Area 15 are located at the U.S. Environmental Protection Agency Farm and are related to waste disposal activities at the farm. Sources of possible contamination at Area 6 include potentially contaminated process waste effluent discharged through a process waste system, a sanitary waste stream generated within buildings of the Decon Facility, and radiologically contaminated materials stored within a portion of the facility yard. At Area 15, sources of potential contamination are associated with the dairy operations and the animal tests and experiments involving radionuclide uptake. Identified contaminants of potential concern …
Date: May 3, 2004
Creator: United States. National Nuclear Security Administration. Nevada Site Office.
Object Type: Report
System: The UNT Digital Library
Carbon Sequestration on Surface Mine Lands Quarterly Report (open access)

Carbon Sequestration on Surface Mine Lands Quarterly Report

The January-March 2004 Quarter was dedicated to tree planting activities in two locations in Kentucky. During year one of this project there was no available mine land to plant in the Hazard area so 107 acres were planted in the Martin county mine location. This year 120 acres was planted in the Hazard area to compensate for the prior year and an additional 57 acres was planted on Peabody properties in western Kentucky. An additional set of special plots were established on each of these areas that contained 4800 seedlings each for special carbon sequestration determinations. Plantings were also conducted to continue compaction and water quality studies on two newly established areas as well as confirmed measurements on the first years plantings. Total plantings on this project now amount to 357 acres containing 245,960 tree seedlings.
Date: May 19, 2004
Creator: Graves, Donald H.; Barton, Christopher; Sweigard, Richard & Warner, Richard
Object Type: Report
System: The UNT Digital Library
Navier-Stokes Neutral and Plasma Fluid Modelling in 3D (open access)

Navier-Stokes Neutral and Plasma Fluid Modelling in 3D

The 3D finite volume transport code BoRiS is applied to a system of coupled plasma and neutral fluid equations in a slab. Demonstrating easy implementation of new equations, a new parallel BoRiS version is tested on three different models for the neutral fluid - diffusive, parallel Navier-Stokes and full Navier-Stokes - and the results are compared to each other. Typical effects like density enhancement by ionization of recycled neutrals in front of a target plate can be seen and differences are linked to the neutral models in use.
Date: May 17, 2004
Creator: Riemann, J.; Borchardt, M.; Schneider, R.; Mutzke, A.; Rognlien, T. & Umansky, M.
Object Type: Article
System: The UNT Digital Library
INNOVATIVE ELECTROMAGNETIC SENSORS FOR PIPELINE CRAWLERS (open access)

INNOVATIVE ELECTROMAGNETIC SENSORS FOR PIPELINE CRAWLERS

Internal inspection of pipelines is an important tool for ensuring safe and reliable delivery of fossil energy products. However, not all pipelines can be inspected with current systems that move inside the pipeline propelled by the product flow. Inspection platforms that crawl slowly inside a pipeline are being developed to maneuver past the physical barriers that limit inspection. Battelle is building innovative electromagnetic sensors for pipeline crawlers. The various sensor types will assess a wide range of pipeline anomalies including corrosion, mechanical damage, cracking and seam weld defects. An implementation of two electromagnetic sensors were designed and tested. A pulsed eddy current system that uses sensors to measure the decay of induced eddy currents to establish the wall thickness has excellent potential. The results of experiments are comparable with magnetic flux leakage detecting 10% metal loss steps following a monotonic increase in signal strength. A rotating permanent remote field eddy current exciter was designed and built to produce strong signal levels at the receiver and reduce power consumption. Midway through the development of each technology, both sensor systems have produced results that warrant further development.
Date: May 1, 2004
Creator: Nestleroth, J. Bruce
Object Type: Report
System: The UNT Digital Library
Surrogate/spent fuel sabotage : aerosol ratio test program and Phase 2 test results. (open access)

Surrogate/spent fuel sabotage : aerosol ratio test program and Phase 2 test results.

A multinational test program is in progress to quantify the aerosol particulates produced when a high energy density device, HEDD, impacts surrogate material and actual spent fuel test rodlets. This program provides needed data that are relevant to some sabotage scenarios in relation to spent fuel transport and storage casks, and associated risk assessments; the program also provides significant political benefits in international cooperation. We are quantifying the spent fuel ratio, SFR, the ratio of the aerosol particles released from HEDD-impacted actual spent fuel to the aerosol particles produced from surrogate materials, measured under closely matched test conditions. In addition, we are measuring the amounts, nuclide content, size distribution of the released aerosol materials, and enhanced sorption of volatile fission product nuclides onto specific aerosol particle size fractions. These data are crucial for predicting radiological impacts. This document includes a thorough description of the test program, including the current, detailed test plan, concept and design, plus a description of all test components, and requirements for future components and related nuclear facility needs. It also serves as a program status report as of the end of FY 2003. All available test results, observations, and analyses - primarily for surrogate material Phase …
Date: May 1, 2004
Creator: Borek, Theodore Thaddeus, III; Thompson, N. Slater; Sorenson, Ken Bryce; Hibbs, R. S.; Nolte, Oliver; Molecke, Martin Alan et al.
Object Type: Report
System: The UNT Digital Library
Oxidative Dna Damage Background Estimated by a System Model of Base Excision Repair (open access)

Oxidative Dna Damage Background Estimated by a System Model of Base Excision Repair

Human DNA can be damaged by natural metabolism through free radical production. It has been suggested that the equilibrium between innate damage and cellular DNA repair results in an oxidative DNA damage background that potentially contributes to disease and aging. Efforts to quantitatively characterize the human oxidative DNA damage background level based on measuring 8-oxoguanine lesions as a biomarker have led to estimates varying over 3-4 orders of magnitude, depending on the method of measurement. We applied a previously developed and validated quantitative pathway model of human DNA base excision repair, integrating experimentally determined endogenous damage rates and model parameters from multiple sources. Our estimates of at most 100 8-oxoguanine lesions per cell are consistent with the low end of data from biochemical and cell biology experiments, a result robust to model limitations and parameter variation. Our results show the power of quantitative system modeling to interpret composite experimental data and make biologically and physiologically relevant predictions for complex human DNA repair pathway mechanisms and capacity.
Date: May 13, 2004
Creator: Sokhansanj, B. A. & Wilson, D. M., III
Object Type: Article
System: The UNT Digital Library
Statistical Hot Spot Model for Explosive Detonation (open access)

Statistical Hot Spot Model for Explosive Detonation

The Non-local Thermodynamic Equilibrium Statistical Hot Spot Model (NLTE SHS), a new model for explosive detonation, is described. In this model, the formation, ignition, propagation, and extinction of hot spots is explicitly modeled. The equation of state of the explosive mixture is treated with a nonlocal equilibrium thermodynamic assumption. A methodology for developing the parameters for the model is discussed, and applied to the detonation velocity diameter effect. Examination of these results indicates where future improvements to the model can be made.
Date: May 10, 2004
Creator: Nichols, A. L., III
Object Type: Article
System: The UNT Digital Library
Valence band hybridization in N-rich GaN1-xAsx alloys (open access)

Valence band hybridization in N-rich GaN1-xAsx alloys

We have used photo-modulated transmission and optical absorption spectroscopies to measure the composition dependence of interband optical transitions in N-rich GaN{sub 1-x}As{sub x} alloys with x up to 0.06. The direct bandgap gradually decreases as x increases. In the dilute x limit, the observed band gap approaches 2.8 eV; this limiting value is attributed to a transition between the As localized level, which has been previously observed in As-doped GaN at 0.6 eV above the valence band maximum in As-doped GaN, and the conduction band minimum. The structure of the valence band of GaN{sub 1-x}As{sub x} is explained by the hybridization of the localized As states with the extended valence band states of GaN matrix. The hybridization is directly confirmed by soft x-ray emission experiments. To describe the electronic structure of the GaN{sub 1-x}As{sub x} alloys in the entire composition range a linear interpolation is used to combine the effects of valence band hybridization in N-rich alloys with conduction band anticrossing in As-rich alloys.
Date: May 4, 2004
Creator: Wu, J.; Walukiewicz, W.; Yu, K. M.; Denlinger, J. D.; Shan, W.; Ager, J. W., III et al.
Object Type: Article
System: The UNT Digital Library
Simultaneous Microwave Imaging System for Density and Temperature Fluctuation Measurements on TEXTOR (open access)

Simultaneous Microwave Imaging System for Density and Temperature Fluctuation Measurements on TEXTOR

Diagnostic systems for fluctuation measurements in plasmas have, of necessity, evolved from simple 1-D systems to multi-dimensional systems due to the complexity of the MHD and turbulence physics of plasmas illustrated by advanced numerical simulations. Using the recent significant advancements in millimeter wave imaging technology, Microwave Imaging Reflectometry (MIR) and Electron Cyclotron Emission Imaging (ECEI), simultaneously measuring density and temperature fluctuations, are developed for TEXTOR. The MIR system was installed on TEXTOR and the first experiment was performed in September, 2003. Subsequent MIR campaigns have yielded poloidally resolved spectra and assessments of poloidal velocity. The new 2-D ECE Imaging system (with a total of 128 channels), installed on TEXTOR in December, 2003, successfully captured a true 2-D images of Te fluctuations of m=1 oscillation (''sawteeth'') near the q {approx} 1 surface for the first time.
Date: May 7, 2004
Creator: Park, H.; Mazzucato, E.; Munsat, T.; Domier, C. W.; Johnson, M.; N. C. Luhmann, Jr. et al.
Object Type: Report
System: The UNT Digital Library
New Results with the superconducting ECR ion source VENUS (open access)

New Results with the superconducting ECR ion source VENUS

During the last year, the VENUS ECR ion source was commissioned at 18 GHz and preparations for 28 GHz operation, which is set to begin early in 2004, are now underway. The goal of the VENUS ECR ion source project as the RIA R&D injector is the production of 240emA of U30+, a high current medium charge state beam. On the other hand, as an injector ion source for the 88-Inch Cyclotron the design objective is the production of 5emA of U48+, a low current, very high charge state beam. During the commissioning phase with 18 GHz, tests with various gases and recently metals have been performed with up to 2000 W RF power and the performance is very promising. For example, 1100 e mu A of O6+,180 e mu A of Ar12+, 150 emA of Xe20+ and 100 emA of Bi24+ were produced in the early commissioning phase, ranking VENUS among the currently highest performance 18 GHz ECR ion sources. The emittance of the beams produced at 18 GHz was measured with a two axis emittance scanner. In FY04 a 10 kW, 28 GHz gyrotron system will be added, which will enable VENUS to reach full performance. The performance …
Date: May 13, 2004
Creator: Lyneis, C. M.; Leitner, D.; Abbott, S. R.; Dwinell, R. D.; Leitner, M.; Silver, C. S. et al.
Object Type: Article
System: The UNT Digital Library