A 1 MEGAWATT POLYPHASE BOOST CONVERTER-MODULATOR FOR KLYSTRON PULSE APPLICATION (open access)

A 1 MEGAWATT POLYPHASE BOOST CONVERTER-MODULATOR FOR KLYSTRON PULSE APPLICATION

This paper describes electrical design criteria and first operational results a 140 kV, 1 MW average, 11 MW peak, zero-voltage-switching 20 kHz polyphase bridge, boost converter/modulator for klystron pulse application. The DC-DC converter derives the buss voltages from a standard 13.8 kV to 2300 Y substation cast-core transformer. Energy storage and filtering is provided by self-clearing metallized hazy polypropylene traction capacitors. Three ''H-Bridge'' Insulated Gate Bipolar Transistor (IGBT) switching networks are used to generate the polyphase 20 kHz transformer primary drive waveforms. The 20 kHz drive waveforms are chirped the appropriate duration to generate the desired klystron pulse width. PWM (pulse width modulation) of the individual 20 kHz pulses is utilized to provide regulated output waveforms with adaptive feedforward and feedback techniques. The boost transformer design utilizes amorphous nanocrystalline material that provides the required low core loss at design flux levels and switching frequencies. Resonant shunt-peaking is used on the transformer secondary to boost output voltage and resonate transformer leakage inductance. With the appropriate transformer leakage inductance and peaking capacitance, zero-voltage-switching of the IGBT's is attained, minimizing switching losses. A review of these design parameters and the first results of the performance characteristics will be presented.
Date: June 1, 2001
Creator: Reass, W. A.; Doss, J. D. & Gribble, R. F.
Object Type: Article
System: The UNT Digital Library
10 (micro)m and 5 (micro)m Pinhole-Assisted Point-Projection Backlit Imaging for NIF (open access)

10 (micro)m and 5 (micro)m Pinhole-Assisted Point-Projection Backlit Imaging for NIF

Pinhole-assisted point-projection backlighting with 10{micro}m and 5 {micro}m pinholes placed a small distance of order 1 mm away from the backlighter produces images with large field of view and high resolution. Pinholes placed closely to high-power backlighter sources can vaporize and close due to x-ray driven ablation, thereby limiting the usefulness of this method. A study of streaked 1-D backlit imaging of 25 {micro}m W wires using the OMEGA laser is presented. The pinhole closure timescale for 10 {micro}m pinholes placed 0.45 mm and 1 mm distant from the backlighter is 1.3 ns and 2.2 ns, respectively. Similar timescales for 5 {micro}m pinholes is also presented. Successful wire imaging prior to pinhole closure is clearly demonstrated.
Date: June 5, 2001
Creator: Bullock, A. B.; Landen, O. L. & Bradley, D. K.
Object Type: Article
System: The UNT Digital Library
17th Edition of TOP500 List of World's Fastest SupercomputersReseased (open access)

17th Edition of TOP500 List of World's Fastest SupercomputersReseased

17th Edition of TOP500 List of World's Fastest Supercomputers Released MANNHEIM, GERMANY; KNOXVILLE, TENN.; BERKELEY, CALIF. In what has become a much-anticipated event in the world of high-performance computing, the 17th edition of the TOP500 list of the world's fastest supercomputers was released today (June 21). The latest edition of the twice-yearly ranking finds IBM as the leader in the field, with 40 percent in terms of installed systems and 43 percent in terms of total performance of all the installed systems. In second place in terms of installed systems is Sun Microsystems with 16 percent, while Cray Inc. retained second place in terms of performance (13 percent). SGI Inc. was third both with respect to systems with 63 (12.6 percent) and performance (10.2 percent).
Date: June 21, 2001
Creator: Strohmaier, Erich; Meuer, Hans W.; Dongarra, Jack J. & Simon,Horst D.
Object Type: Report
System: The UNT Digital Library
2nd Feasibility Study of a Muon Storage Ring Neutrino Factory (open access)

2nd Feasibility Study of a Muon Storage Ring Neutrino Factory

The design and simulated performance of a second feasibility study are presented. The efficiency of producing muons is {approx} 0.17 {micro}/p with 24 GeV protons. This study was sponsored by the BNL Director, with BNL site specific driver and layout. It was a follow on to the First Study[2] sponsored by the Fermilab Director, with Fermilab site specific driver and layout, and was the main US collaboration conceptual effort during the past year. Other studies, and technical work by the collaboration is reported in other papers.
Date: June 18, 2001
Creator: Ozaki, S.; Palmer, R. B. & Zisman, M. S.
Object Type: Article
System: The UNT Digital Library
Accelerator Physics Issues for Future Electron Ion Colliders (open access)

Accelerator Physics Issues for Future Electron Ion Colliders

Interest continues to grow in the physics of collisions between electrons and heavy ions, and between polarized electrons and polarized protons [1,2,3]. Table 1 compares the parameters of some machines under discussion. DESY has begun to explore the possibility of upgrading the existing HERA-p ring to store heavy ions, in order to collide them with electrons (or positrons) in the HERA-e ring, or from TESLA [4]. An upgrade to store polarized protons in the HERA-p ring is also under discussion [1]. BNL is considering adding polarized electrons to the RHIC repertoire, which already includes heavy and light ions, and polarized protons. The authors of this paper have made a first pass analysis of this ''eRHIC'' possibility [5]. MIT-BATES is also considering electron ion collider designs [6].
Date: June 18, 2001
Creator: Peggs, S.; Ben-Zvi, Ilan; Kewisch, J. & Murphy, J.
Object Type: Article
System: The UNT Digital Library
Accuracy of Projection Methods for the Incompressible Navier-Stokes Equations (open access)

Accuracy of Projection Methods for the Incompressible Navier-Stokes Equations

Numerous papers have appeared in the literature over the past thirty years discussing projection-type methods for solving the incompressible Navier-Stokes equations. A recurring difficulty encountered is the choice of boundary conditions for the intermediate or predicted velocity in order to obtain at least second order convergence. A further issue is the formula for the pressure correction at each timestep. A simple overview is presented here based on recently published results by Brown, Cortez and Minion [2].
Date: June 12, 2001
Creator: Brown, D L
Object Type: Article
System: The UNT Digital Library
Acoustic Monitor for Liquid Solid Slurries Measurements at Low Weight Fractions (open access)

Acoustic Monitor for Liquid Solid Slurries Measurements at Low Weight Fractions

The principal objective of the project is to develop an acoustic probe for determining the volume fraction of particles in a flowing suspension. This will include testing the theory of acoustic wave propagation in suspensions and demonstrating the application of the probe by installing it on a flow loop through which a suspension is flowing and determining the particle volume fraction. The signal from the probe must be processed such that the noise arising from the presence of the gas bubbles, if present in the system, is removed to yield an accurate estimate of the particle volume fraction. Once the probe is developed and tested successfully at Syracuse University, it is to be installed and tested in the flow loop at Oak Ridge National Laboratories for surrogate slurries for the Hanford Nuclear site. Particular attention is to be given to testing suspensions with low particle volume fractions since slurries to be transported in nuclear waste processing will have low particle volume fractions.
Date: June 1, 2001
Creator: Taularides, L. L. & Sangani, A.
Object Type: Report
System: The UNT Digital Library
Acquisition of building geometry in the simulation of energy performance (open access)

Acquisition of building geometry in the simulation of energy performance

Building geometry is essential to any simulation of building performance. This paper examines the importing of building geometry into simulation of energy performance from the users' point of view. It lists performance requirements for graphic user interfaces that input building geometry, and discusses the basic options in moving from two- to three-dimensional definition of geometry and the ways to import that geometry into energy simulation. The obvious answer lies in software interoperability. With the BLIS group of interoperable software one can interactively import building geometry from CAD into EnergyPlus and dramatically reduce the effort otherwise needed for manual input.The resulting savings may greatly increase the value obtained from simulation, the number of projects in which energy performance simulation is used, and expedite decision making in the design process.
Date: June 28, 2001
Creator: Bazjanac, Vladimir
Object Type: Article
System: The UNT Digital Library
ACTINIDE-ALUMINATE SPECIATION IN ALKALINE RADIOACTIVE WASTE (open access)

ACTINIDE-ALUMINATE SPECIATION IN ALKALINE RADIOACTIVE WASTE

Highly alkaline radioactive waste tanks contain a number of transuranic species, in particular U, Np, Pu, and Am--the exact forms of which are currently unknown. Knowledge of actinide speciation under highly alkaline conditions is essential towards understanding and predicting their solubility and sorption behavior in tanks, determining whether chemical separations are needed for waste treatment, and designing separations processes. Baseline washing of tank sludges with NaOH solutions is being proposed to reduce the volume of HLW. Alkaline pretreatment of HLW will be needed to remove aluminum [as NaAl(OH){sub 4}] because it significantly reduces the HLW volume; however, aluminate [Al(OH){sub 4}{sup -}] enhances actinide solubility via an unknown mechanism. Thus, alkaline wash residues may require an additional treatment to remove actinides. The results of this research will determine the nature TRU (Np, Pu, Am) speciation with aluminate anions under alkaline, oxidizing tank-like conditions. Specific issues to be addressed include solubility of these actinides, speciation in aluminate-containing alkaline supernatants, the role of actinide redox states on solubility, and partitioning between supernatant and solid phases, including colloids. Studies will include thermodynamics, kinetics, spectroscopy, electrochemistry, etc. It is already known, for example, that certain high valent forms of NF and Pu are very soluble …
Date: June 1, 2001
Creator: Clark-Deaborg, David
Object Type: Report
System: The UNT Digital Library
Adaptive response against spontaneous neoplastic transformation induced by low dose ionizing radiation (open access)

Adaptive response against spontaneous neoplastic transformation induced by low dose ionizing radiation

This project is being conducted to ascertain the shape of the dose response curve for neoplastic transformation in vitro over the dose range 0.0 to 10 cGy, and to determine how this depends on radiation quality and dose fractionation. Preliminary data already have indicated that at a dose of 1 cGy the induced transformation frequency is less than the spontaneous transformation frequency. The results will be compared with animal and human epidemiological data on the induction of cancer by low doses of radiation. This will hopefully allow for a more informed estimation of the risk of cancer induction at low doses.
Date: June 1, 2001
Creator: Redpath, J. Leslie
Object Type: Report
System: The UNT Digital Library
Addendum to Revision 1 of the Corrective Action Investigation Plan for Corrective Action Unit 98: Frenchman Flat, Nevada Test Site, Nevada (Addendum Revision No. 1) (open access)

Addendum to Revision 1 of the Corrective Action Investigation Plan for Corrective Action Unit 98: Frenchman Flat, Nevada Test Site, Nevada (Addendum Revision No. 1)

This document is submitted as an addendum to the Corrective Action Investigation Plan (CAIP) for Corrective Action Unit (CAU) 98: Frenchman Flat, Nevada Test Site (NTS), Nevada. The addendum was prepared to propose work activities in response to comments resulting from the U.S. Department of Energy's (DOE's) review of the draft Frenchman Flat CAU model of groundwater flow and contaminant transport completed in April 1999. The reviewers included an external panel of experts and the Nevada Division of Environmental Protection. As a result of the review, additional work scope, including new data-collection and modeling activities, has been identified for the Frenchman Flat CAU. The proposed work scope described in this addendum will be conducted in accordance with the revised Underground Test Area strategy contained in the December 2000 amendment to the Federal Facility Agreement and Consent Order. The Frenchman Flat CAU model is a group of interdependent models designed to predict the extent of contamination in groundwater due to the underground nuclear tests conducted within this CAU. At the time of the DOE review, the CAU model consisted of a CAU groundwater flow and transport model comprised of two major components: a groundwater flow model and a recharge model. The …
Date: June 6, 2001
Creator: U.S. Department of Energy, National Nuclear Security Administration Nevada Operations Office
Object Type: Report
System: The UNT Digital Library
Adjustable permanent quadrupoles for the next linear collider (open access)

Adjustable permanent quadrupoles for the next linear collider

The proposed Next Linear Collider (NLC) will require over 1400 adjustable quadrupoles between the main linacs' accelerator structures. These 12.7 mm bore quadrupoles will have a range of integrated strength from 0.6 to 138 Tesla, with a maximum gradient of 141 Tesla per meter, an adjustment range of +0 to {minus}20% and effective lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micron during the 20% adjustment. In an effort to reduce costs and increase reliability, several designs using hybrid permanent magnets have been developed. Four different prototypes have been built. All magnets have iron poles and use Samarium Cobalt to provide the magnetic fields. Two use rotating permanent magnetic material to vary the gradient, one uses a sliding shunt to vary the gradient and the fourth uses counter rotating magnets. Preliminary data on gradient strength, temperature stability, and magnetic center position stability are presented. These data are compared to an equivalent electromagnetic prototype.
Date: June 22, 2001
Creator: al., James T. Volk et
Object Type: Article
System: The UNT Digital Library
ADTF SUPERCONDUCTING LINAC DESIGN (open access)

ADTF SUPERCONDUCTING LINAC DESIGN

None
Date: June 1, 2001
Creator: GARNETT, R. W.
Object Type: Article
System: The UNT Digital Library
Advanced High Resolution Seismic Imaging, Material Properties Estimation and Full Wavefield Inversion for the Shallow Subsurface (open access)

Advanced High Resolution Seismic Imaging, Material Properties Estimation and Full Wavefield Inversion for the Shallow Subsurface

Develop and test advanced near vertical to wide-angle seismic methods for structural imaging and material properties estimation of the shallow subsurface for environmental characterization efforts.
Date: June 14, 2001
Creator: Levander, A.; Zelt, C. A. & Symes, W. W.
Object Type: Report
System: The UNT Digital Library
Agent-based modeling of complex infrastructures (open access)

Agent-based modeling of complex infrastructures

Complex Adaptive Systems (CAS) can be applied to investigate complex infrastructures and infrastructure interdependencies. The CAS model agents within the Spot Market Agent Research Tool (SMART) and Flexible Agent Simulation Toolkit (FAST) allow investigation of the electric power infrastructure, the natural gas infrastructure and their interdependencies.
Date: June 2001
Creator: North, M. J.
Object Type: Article
System: The UNT Digital Library
AHF BEAMS TRANSPORT LATTICE CRYOSYSTEMS[Advanced Hydrotest Facility] (open access)

AHF BEAMS TRANSPORT LATTICE CRYOSYSTEMS[Advanced Hydrotest Facility]

None
Date: June 1, 2001
Creator: KELLEY, J. P. & MULHOLLAND, G. T.
Object Type: Article
System: The UNT Digital Library
AHF MAGNETIC LENS CRYOSYSTEMS[Advanced Hydrotest Facility] (open access)

AHF MAGNETIC LENS CRYOSYSTEMS[Advanced Hydrotest Facility]

None
Date: June 1, 2001
Creator: KELLEY, J. P. & MULHOLLAND, G. T.
Object Type: Article
System: The UNT Digital Library
All-Ferrite RHIC Injection Kicker (open access)

All-Ferrite RHIC Injection Kicker

Ion beams are transferred from the AGS into RHIC in boxcar fashion as single bunches. The nominal design assumes 60 bunches per ring but increasing the number of bunches to gain luminosity is possible, thereby requiring injection kickers with a shorter rise time. The original injection system consists of traveling-wave dielectric loaded kicker magnets and a Blumlein pulser with a rise time adequate for the present operation. Voltage breakdown in the dielectric kickers suggested the use of all-ferrite magnets. In order to minimize the conversion cost, the design of the all-ferrite kicker uses the same components as the dielectric loaded units. The all-ferrite kickers showed in bench measured good breakdown properties and a current rise time of < 50 ns. A prototype kicker has been installed in the blue ring and was tested with beam. Beam measurements indicate suitability of all-ferrite kicker magnets for upgraded operation.
Date: June 18, 2001
Creator: Hahn, H.; Fischer, W.; Ptitsyn, V. I. & Tuozzolo, J. E.
Object Type: Article
System: The UNT Digital Library
Alpha particle response characterization of CdZnTe (open access)

Alpha particle response characterization of CdZnTe

The coplanar-grid as well as other electron-only detection techniques are effective in overcoming some of the material problems of CdZnTe and, consequently, have led to efficient gamma-ray detectors with good energy resolution while operating at room temperature. The performance of these detectors is limited by the degree of uniformity in both electron generation and transport. Despite recent progress in the growth of CdZnTe material, small variations in these properties remain a barrier to the widespread success of such detectors. Alpha-particle response characterization of CdZnTe crystals fabricated into simple planar detectors is an effective tool to accurately study electron generation and transport. We have used a finely collimated alpha source to produce two-dimensional maps of detector response. A clear correlation has been observed between the distribution of precipitates near the entrance contact on some crystals and their alpha-response maps. Further studies are ongoing to determine the mechanism for the observed response variations and the reason for the correlation. This paper presents the results of these studies and their relationship to coplanar-grid gamma-ray detector performance.
Date: June 28, 2001
Creator: Amman, Mark; Lee, Julie S. & Luke, Paul N.
Object Type: Article
System: The UNT Digital Library
An Alternative Approach to Low Frequency Rf Accelerators and Power Sources. (open access)

An Alternative Approach to Low Frequency Rf Accelerators and Power Sources.

The Muon Collider and Neutrino Factory projects require low frequency rf cavities because the size and emittance of the muon beam is much larger than is usual for electron or proton beams. The range of 30 MHz to 200 MHz is of special interest. However, the size of an accelerator with low frequency will be impractically large if it is simply scaled up from usual designs. In addition, to get very high peak power in this range is difficult. Presented in this paper is an alternative structure that employs a quasi-lumped inductance that can significantly reduce the transverse size while keeping high gradient. Also addressed is a power compression scheme with a thyratron. This gives a possible solution to provide very high peak power.
Date: June 18, 2001
Creator: Zhao, Y.
Object Type: Article
System: The UNT Digital Library
ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS (open access)

ALTERNATIVE FUELS AND CHEMICALS FROM SYNTHESIS GAS

None
Date: June 30, 2001
Creator: unknown
Object Type: Report
System: The UNT Digital Library
An Alternative Scheme for the Neutrino Factory With a High Power Proton Driver. (open access)

An Alternative Scheme for the Neutrino Factory With a High Power Proton Driver.

We describe a scheme to produce an intense and collimated beam of neutrinos for the neutrino-oscillation experiment. The scheme feature is the presence of a Proton Driver that generates a proton beam at very large power (10mA x 15GeV), considerably higher than that proposed elsewhere for this application. With this scheme, because of the high intensity of the proton beam, to produce neutrinos at the same required rates, it is sufficient to collect {pi} and {mu} mesons only around a small angle and at reduced momentum spreads. This eliminates the need for the difficult longitudinal manipulations of the protons and mesons, and of the ionization cooling that still needs to be demonstrated. It is also shown, at the end of the paper, that the Neutrino Factory here proposed can also be used as an injector for a 1 x 1 TeV{sup 2} {mu}{sup +} - {mu}{sup -} collider at large luminosity.
Date: June 30, 2001
Creator: Ruggiero, A. G.
Object Type: Article
System: The UNT Digital Library
Al Alternative Scheme for the Neutrino Factory With a High Power Proton Driver. (open access)

Al Alternative Scheme for the Neutrino Factory With a High Power Proton Driver.

We describe a scheme to produce an intense and collimated beam of neutrinos for the neutrino-oscillation experiment. The scheme feature is the presence of a Proton Driver that generates a proton beam at very large power (10mA x 15GeV), considerably higher than that proposed elsewhere for this application. With this scheme, because of the high intensity of the proton beam, to produce neutrinos at the same required rates, it is sufficient to collect {pi} and {mu} mesons only around a small angle and at reduced momentum spreads. This eliminates the need for the difficult longitudinal manipulations of the protons and mesons, and of the ionization cooling that still needs to be demonstrated. It is also shown, at the end of the paper, that the Neutrino Factory here proposed can also be used as an injector for a 1 x 1 TeV{sup 2} {mu}{sup +}-{mu}{sup -} collider at large luminosity.
Date: June 30, 2001
Creator: Ruggiero, A. G.
Object Type: Article
System: The UNT Digital Library
American Electric Power's Conesville Power Plant Unit No. 5 CO2 Capture Retrofit Study (open access)

American Electric Power's Conesville Power Plant Unit No. 5 CO2 Capture Retrofit Study

ALSTOM Power Inc.'s Power Plant Laboratories (ALSTOM) has teamed with American Electric Power (AEP), ABB Lummus Global Inc. (ABB), the US Department of Energy National Energy Technology Laboratory (DOE NETL), and the Ohio Coal Development Office (OCDO) to conduct a comprehensive study evaluating the technical feasibility and economics of alternate CO{sub 2} capture and sequestration technologies applied to an existing US coal-fired electric generation power plant. The motivation for this study was to provide input to potential US electric utility actions concerning GHG emissions reduction. If the US decides to reduce CO{sub 2} emissions, action would need to be taken to address existing power plants. Although fuel switching from coal to natural gas may be one scenario, it will not necessarily be a sufficient measure and some form of CO{sub 2} capture for use or disposal may also be required. The output of this CO{sub 2} capture study will enhance the public's understanding of control options and influence decisions and actions by government, regulators, and power plant owners in considering the costs of reducing greenhouse gas CO{sub 2} emissions. The total work breakdown structure is encompassed within three major reports, namely: (1) Literature Survey, (2) AEP's Conesville Unit No.5 Retrofit …
Date: June 30, 2001
Creator: Bozzuto, Carl R.; Nsakala, Nsakala ya; Liljedahl, Gregory N.; Palkes, Mark & Marion, John L.
Object Type: Report
System: The UNT Digital Library