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Optimization of the Helical Orbits in the Tevatron

Description: To avoid multiple head-on collisions the proton and antiproton beams in the Tevatron move along separate helical orbits created by 7 horizontal and 8 vertical electrostatic separators. Still the residual long-range beam-beam interactions can adversely affect particle motion at all stages from injection to collision. With increased intensity of the beams it became necessary to modify the orbits in order to mitigate the beam-beam effect on both antiprotons and protons. This report summarizes the … more
Date: June 1, 2007
Creator: Alexahin, Y.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Simulation studies of non-neutral plasma equilibria in anelectrostatic trap with magnetic mirror

Description: The equilibrium of an infinitely long, strongly magnetized, non-neutral plasma confined in a Penning-Malmberg trap with an additional mirror coil has been solved analytically [J. Fajans, Phys. Plasmas 10, 1209 (2003)] and shown to exhibit unusual features. Particles not only reflect near the mirror in the low field region, but also may be weakly trapped in part of in the high field region. The plasma satisfies a Boltzmann distribution along field lines; however, the density and the potential va… more
Date: June 1, 2006
Creator: Gomberoff, K.; Fajans, J.; Wurtele, J.; Friedman, A.; Grote, D. P.; Cohen, R. H. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Simulating Electron Effects in Heavy-Ion Accelerators with Solenoid Focusing

Description: Contamination from electrons is a concern for solenoid-focused ion accelerators being developed for experiments in high-energy-density physics. These electrons, produced directly by beam ions hitting lattice elements or indirectly by ionization of desorbed neutral gas, can potentially alter the beam dynamics, leading to a time-varying focal spot, increased emittance, halo, and possibly electron-ion instabilities. The electrostatic particle-in-cell code WARP is used to simulate electron-cloud st… more
Date: June 20, 2007
Creator: Sharp, W. M.; Grote, D. P.; Cohen, R. H.; Friedman, A.; Molvik, A. W.; Vay, J. L. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Three-Dimensional Quasistatic Model for High Brightness Beam Dynamics Simulation

Description: In this paper, we present a three-dimensional quasistatic model for high brightness beam dynamics simulation in rf/dc photoinjectors, rf linacs, and similar devices on parallel computers. In this model, electrostatic space-charge forces within a charged particle beam are calculated self-consistently at each time step by solving the three-dimensional Poisson equation in the beam frame and then transforming back to the laboratory frame. When the beam has a large energy spread, it is divided into … more
Date: June 19, 2006
Creator: Qiang, Ji; Lidia, S.; Ryne, R. D. & Limborg-Deprey, C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Physical Properties of Hanford Transuranic Waste Sludge

Description: Equipment that was purchased in the abbreviated year 1 of this project has been used during year 2 to study the fundamental behavior of materials that simulate the behavior of the Hanford transuranic waste sludge. Two significant results have been found, and each has been submitted for publication. Both studies found non-DLVO behavior in simulant systems. These separate but related studies were performed concurrently. It was previously shown in Rassat et al.'s report Physical and Liquid Chemica… more
Date: June 1, 2005
Creator: Berg, John C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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First Wall and Operational Diagnostics

Description: In this chapter we review numerous diagnostics capable of measurements at or near the first wall, many of which contribute information useful for safe operation of a tokamak. There are sections discussing infrared cameras, visible and VUV cameras, pressure gauges and RGAs, Langmuir probes, thermocouples, and erosion and deposition measurements by insertable probes and quartz microbalance. Also discussed are dust measurements by electrostatic detectors, laser scattering, visible and IR cameras, … more
Date: June 19, 2006
Creator: Lasnier, C.; Allen, S.; Boedo, J.; Groth, M.; Brooks, N.; McLean, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Simulation studies of non-neutral plasma equilibria in an electrostatic trap with a magnetic mirror

Description: The equilibrium of an infinitely long, strongly magnetized, non-neutral plasma confined in a Penning-Malmberg trap with an additional mirror coil has been solved analytically [J. Fajans, Phys. Plasmas 10, 1209 (2003)] and shown to exhibit unusual features. Particles not only reflect near the mirror in the low field region, but also may be weakly trapped in part of in the high field region. The plasma satisfies a Boltzmann distribution along field lines; however, the density and the potential va… more
Date: June 5, 2006
Creator: Gomberoff, K; Fajans, J; Wurtele, J; Friedman, A; Grote, D P; Cohen, R H et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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New possibilities for beam-beam and space-charge compensation: MCP gun and electron columns

Description: We propose to use microchannel plate (MCP) as a gigantic quantum efficiency photo-cathode in electron guns. Another proposal is to use electron columns formed by ionization electrons in a longitudinal magnetic field for compensation of space charge effects in high intensity proton synchrotrons. Strong magnetic field is to assure that transverse distribution of electron space charge in the column is the same as in proton beam. Electrostatic electrodes are to control the accumulation and release … more
Date: June 1, 2007
Creator: Shiltsev, V.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Survey of Collective Instabilities and Beam-Plasma Interactions in Intense Heavy Ion Beams

Description: This paper presents a survey of the present theoretical understanding based on advanced analytical and numerical studies of collective processes and beam-plasma interactions in intense heavy ion beams for applications to ion-beam-driven high energy density physics and heavy ion fusion. The topics include: discussion of the conditions for quiescent beam propagation over long distances; and the electrostatic Harris instability and the transverse electromagnetic Weibel instability in highly anisot… more
Date: June 19, 2008
Creator: Davidson, Ronald C.; Dorf, Mikhail A.; Kaganovich, Igor D.; Qin, Hong; Startsev, Edward A.; Rose, David V. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Coherent instabilities of a relativistic bunched beam

Description: A charge-particle beam contained in an accelerator vacuum chamber interacts electromagnetically with its environment to create a wake field. This field than acts back on the beam, perturbing the particle motion. If the beam intensity is high enough, this beam-environment interaction may lead to an instability and to subsequent beam loss. The beam and its environment form a dynamical system, and it is this system that will be studied. 84 references.
Date: June 1, 1982
Creator: Chao, A.W.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Quasi-static electric field build-up between two spherical conductors

Description: It has been observed that the exposure of dielectrics to electron beams can produce electric fields of sufficient magnitude to cause dielectric break-down. It is the purpose of this investigation to calculate the electric fields for two of the geometric shapes of common interest: spherical shells and cylinders. This report summarizes the work done to date on spherical dielectric shells with an inner and outer conducting surface which are traversed by an electron beam through the sphere's center… more
Date: June 1, 1979
Creator: Yee, K.S. & Kasher, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Interaction of a stream of dielectric spheres in an electric field in a high vacuum

Description: The interaction of a stream of dielectric spheres in an electric field in a high vacuum is investigated both theoretically and experimentally. This investigation is motivated by an elaborate attempt to detect fractional electric charges which might exist in matter, namely, a search for isolated quarks in matter. The theoretical analysis is intended for pinpointing the basic interaction mechanism by which a stream of dielectric spheres becomes destablized in an electric field. One important resu… more
Date: June 14, 1983
Creator: Hendricks, C.D. & Kim, K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Non-intrusive measurement of particle charge: Electrostatic dry coal cleaning. Technical progress report No. 11, January 1, 1994--March 31, 1994

Description: As has been previously reported, the charge measurement portion of this project has been broadened to include direct measurement techniques which yield an average particle charge per unit mass. These methods, which now include current measurements from the charging loop, an electrolytic collection solution and a Faraday cage have been employed to expand the charge measurement capabilities over those that were originally developed using the PDPA. The effects of gas velocity, humidity and tempera… more
Date: June 1, 1994
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Electrostatic quadrupole focusing in the AGS g-2 storage ring

Description: Electrostatic quadrupole focusing is to be used in the high precision measurement of the anomalous magnetic moment of the muon, AGS Experiment 821. The final design uses planar rather than hyperbolic electrodes, and the field is pulsed to minimize the effect of trapped electrons. The mechanical design is described. Performance in a 1.5T magnetic field at less than 10{sup {minus}6} Torr is reviewed.
Date: June 1, 1993
Creator: Bennett, G.; Larsen, R.; Morse, W.; Semertzidis, Y.; Yelk, J. & Liu, Z.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Characterization of an Effective Cleaning Procedure for Aluminum Alloys: Surface Enhanced Raman Spectroscopy and Zeta Potential Analysis

Description: We have developed a cleaning procedure for aluminum alloys for effective minimization of surface-adsorbed sub-micron particles and non-volatile residue. The procedure consists of a phosphoric acid etch followed by an alkaline detergent wash. To better understand the mechanism whereby this procedure reduces surface contaminants, we characterized the aluminum surface as a function of cleaning step using Surface Enhanced Raman Spectroscopy (SERS). SERS indicates that phosphoric acid etching re-est… more
Date: June 2, 2004
Creator: Cherepy, N J; Shen, T H; Esposito, A P & Tillotson, T M
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Polarized particle levitation in hexapole field

Description: Proposed here is a novel electrostatic levitation scheme which uses the force exerted by a non-uniform electric field on a polarized particle. The scheme differs from conventional quadrupole levitation devices principally in that the levitated particle is uncharged. In order to provide the proper force required to achieve dynamic stabilization, a very intense non-uniform time-varying electric field produced by a three-dimensional hexapole electrode structure is utilized. The primary advantage o… more
Date: June 1, 1976
Creator: Jones, T. B.; Kallio, G. A. & Robinson, K. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Multiple HEPA filter test methods, January--December 1976

Description: The testing of tandem high-efficiency particulate air (HEPA) filter systems is of prime importance for the measurement of accurate overall system protection factors. A procedure, based on the use of an intra-cavity laser particle spectrometer, has been developed for measuring protection factors in the 10/sup 8/ range. A laboratory scale model of a filter system was constructed and initially tested to determine individual HEPA filter characteristics with regard to size and state (liquid or solid… more
Date: June 1, 1977
Creator: Schuster, B.; Kyle, T. & Osetek, D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Air filtration enhancement using electronic techniques

Description: Dielectrophoretic filtration experiments were conducted on glass, polyester, dacron, Teflon, wool, acrylic and polypropylene filter media. A polydispersed (sigma g = 2.0, ammd = 0.95 ..mu.. m) sodium chloride particle was used as a test aerosol. All materials exhibited significant increases in efficiency with increasing field strengths. Efficiencies of greater than 99 percent could be obtained from glass fiber mats using a 13 kV/cm electric field at 16.3 cm/s face velocity.
Date: June 24, 1976
Creator: Nelson, G. O.; Richards, C. P.; Biermann, A. H.; Taylor, R. D. & Miller, H. H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Multinozzle Emitter Arrays for Nanoelectrospray Mass Spectrometry

Description: Mass spectrometry (MS) is the enabling technology for proteomics and metabolomics. However, dramatic improvements in both sensitivity and throughput are still required to achieve routine MS-based single cell proteomics and metabolomics. Here, we report the silicon-based monolithic multinozzle emitter array (MEA), and demonstrate its proof-of-principle applications in high-sensitivity and high-throughput nanoelectrospray mass spectrometry. Our MEA consists of 96 identical 10-nozzle emitters in a… more
Date: June 16, 2011
Creator: Mao, Pan; Wang, Hung-Ta; Yang, Peidong & Wang, Daojing
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Electrostatic Dust Detector with Improved Sensitivity

Description: Methods to measure the inventory of dust particles and to remove dust if it approaches safety limits will be required in next-step tokamaks such as ITER. An electrostatic dust detector, based on a fine grid of interlocking circuit traces, biased to 30 or 50 V, has been developed for the detection of dust on remote surfaces in air and vacuum environments. Gaining operational experience of dust detection on surfaces in tokamaks is important, however the level of dust generated in contemporary sho… more
Date: June 9, 2008
Creator: D.P. Boyle, C.H. Skinner, and A. L. Roquemore
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Physicochemical controls on absorbed water film thickness in unsaturated geological media

Description: Adsorbed water films commonly coat mineral surfaces in unsaturated soils and rocks, reducing flow and transport rates. Therefore, it is important to understand how adsorbed film thickness depends on matric potential, surface chemistry, and solution chemistry. Here, the problem of adsorbed water film thickness is examined through combining capillary scaling with the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Novel aspects of this analysis include determining capillary influences on film thi… more
Date: June 14, 2011
Creator: Tokunaga, T.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A Multi-Beamlet Injector for Heavy Ion Fusion: Experiments and Modeling

Description: We have performed experiments and modeling to evaluate a proposed merging beamlet approach for use in a compact high-brightness Heavy Ion Fusion injector. We used an RF plasma source to produce the initial beamlets. An extraction current density of 100 mA/cm{sup 2} was achieved, and the thermal temperature of the ions was below 1 eV. An array of converging beamlets was used to produce a beam with the envelope radius, convergence, and ellipticity matched to an electrostatic quadrupole channel. E… more
Date: June 19, 2007
Creator: Westenskow, W A; Grote, D; Bieniosek, F & Kwan, J
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Molecular Mechanism of Bacterial Attachment to Fe(III)-Oxide Surfaces

Description: To date, our studies have concentrated upon two aspects of the chemistry and architecture of the Shewanella outer membrane surface: the influence of terminal electron acceptor during anaerobic respiration, and the role that protein secretion systems play in determining the presence and chemistry of exopolymers. Using Shewanella oneidensis strain MR-1 and S. putrefaciens strain 200R as model organisms we have developed a microelectrophoresis approach to estimating cell mobility in solution over … more
Date: June 1, 2006
Creator: Neal, Andrew
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Formation and Reactivity of Biogenic Iron Minerals

Description: Dissimilatory iron-reducing bacteria (DIRB) play an important role in regulating the aqueous geochemistry of iron and other metals in anaerobic, non-sulfidogenic groundwater environments; however, little work has directly assessed the cell surface electrochemistry of DIRB, or the nature of the interfacial environment around individual cells. The electrochemical properties of particulate solids are often inferred from titrations in which net surface charge is determined, assuming electroneutrali… more
Date: June 1, 2002
Creator: Ferris, F. Grant
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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