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A Core-Particle Model for Periodically Focused Ion Beams with Intense Space-Charge

Description: A core-particle model is derived to analyze transverse orbits of test particles evolving in the presence of a core ion beam described by the KV distribution. The core beam has uniform density within an elliptical cross-section and can be applied to model both quadrupole and solenoidal focused beams in periodic or aperiodic lattices. Efficient analytical descriptions of electrostatic space-charge fields external to the beam core are derived to simplify model equations. Image charge effects are a… more
Date: August 2, 2006
Creator: Lund, S M; Barnard, J J; Bukh, B; Chawla, S R & Chilton, S H
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Mechanical and Electrical Properties of CdTe Tetrapods Studied byAtomic Force Microscopy

Description: The mechanical and electrical properties of CdTe tetrapod-shaped nanocrystals have been studied with atomic force microscopy. Tapping mode images of tetrapods deposited on silicon wafers revealed that they contact the surface with the ends of three arms. The length of these arms was found to be 130 {+-} 10 nm. A large fraction of the tetrapods had a shortened vertical arm as a result of fracture during sample preparation. Fracture also occurs when the applied load is a few nanonewtons. Compress… more
Date: August 30, 2007
Creator: Fang, Liang; Park, Jeong Young; Cui, Yi; Alivisatos, Paul; Shcrier, Joshua; Lee, Byounghak et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Electrostatic Modeling of Vacuum Insulator Triple Junctions

Description: A comprehensive matrix of 60 tests was designed to explore the effect of calcium chloride vs. sodium chloride and the ratio R of nitrate concentration over chloride concentration on the repassivation potential of Alloy 22. Tests were conducted using the cyclic potentiodynamic polarization (CPP) technique at 75 C and at 90 C. Results show that at a ratio R of 0.18 and higher nitrate was able to inhibit the crevice corrosion in Alloy 22 induced by chloride. Current results fail to show in a consi… more
Date: August 13, 2007
Creator: Tully, L. K.; White, A. D.; Goerz, D. A.; Javedani, J. B. & Houck, T. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Developing acceleration schedules for NDCX-II

Description: The Virtual National Laboratory for Heavy-Ion Fusion Science is developing a physics design for NDCX-II, an experiment to study warm dense matter heated by ions near the Bragg-peak energy. Present plans call for using about thirty induction cells to accelerate 30 nC of Li+ ions to more than 3 MeV, followed by neutralized drift-compression. To heat targets to useful temperatures, the beam must be compressed to a millimeter-scale radius and a duration of about 1 ns. An interactive 1-D particle-in… more
Date: August 1, 2008
Creator: Sharp, W. M.; Friedman, A.; Grote, D. P.; Henestroza, E.; Leitner, M. A. & Waldron, W. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Fully Electromagnetic Nonlinear Gyrokinetic Equations for Tokamak Edge Turbulence

Description: An energy conserving set of the fully electromagnetic nonlinear gyrokinetic Vlasov equation and Maxwell's equations, which is applicable to both L-mode turbulence with large amplitude and H-mode turbulence in the presence of high E Χ B shear has been derived. The phase-space action variational Lie perturbation method ensures the preservation of the conservation laws of the underlying Vlasov-Maxwell system. Our generalized ordering takes ρ[sub ]i [\sub]<< ρϑ¡ ~ LE ~ Lp << R (here ρ[sub ]i [\sub]… more
Date: August 27, 2008
Creator: Hahm, T.S.; Wang, Lu, & Madsen, J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Finite element method for the solution of a potential theory integral equation

Description: A finite element approximation for an integral equation of the second kind deduced from a potential theory boundary-value problem in two variables is discussed. The equation is shown to admit a unique solution, to be variational and coercive in the Hilbert space of functions sigma an element of H/sup 1/2/(GAMMA), integral/sub GAMMA/sigma d..gamma.. = 0. The Galerkin method with finite elements as trial functions is shown to lead to an optimal rate of convergence.
Date: August 1, 1979
Creator: Friedman, M.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Electrodeless drift chambers with 50-cm drift distance

Description: The electrodeless drift-chamber technique is potentially very useful in applications requiring the drifting of ionization in gas over long distances in narrow channels. Chamber construction is simple and cheap; the technique is well suited to very large detectors operating in low-rate environments. Prototype tests on planar chambers reveal excellent drifting characteristics after the initial charging, but show a substantial degradation of pulse height from cosmic rays over a two-week period. Th… more
Date: August 1982
Creator: Ayres, D. S. & Price, L. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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A SPICE Model and Electrostatic Field Analysis of the MOS Turn-Off Thyristor

Description: This paper presents a circuit model and an electrostatic field analysis with an approximate model of the SDM170HK MOS turn-off thyristor (MTO) fabricated by Silicon Power Corporation. The circuit model consists of five cells, each containing two bipolar junction transistors and three resistors. The turn-off feature of the MTO was simulated by inserting an array of 21 Fairchild FDS6670A MOSFET importable sub-circuit components between the cathode and the turn-on gate. The model was then used to … more
Date: August 5, 2002
Creator: Kelly, D. Q.; Mayhall, D. J.; Wilson, M. J. & Lahowe, D. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Electrostatic direct energy converter performance and cost scaling laws

Description: This study is concerned with electrostatic type direct energy converters for direct recovery of a large fraction of the plasma ion energy from fusion reactors. Simplified equations are presented for each of the important loss mechanisms in both single-stage direct converters and multistage &#x27;&#x27;Venetian Blind&#x27;&#x27; type direct converters. These equations can be used to estimate the efficiency and electric power output of the direct converter subsystem. Scaling relations for the cos… more
Date: August 1, 1977
Creator: Hoffman, M. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Built-in and Induced Polarization Across LaAlO3/SrTiO3 Heterojunctions

Description: Ionic crystals terminated at oppositely charged polar surfaces are inherently unstable and expected to undergo surface reconstructions to maintain electrostatic stability. Essentially, an electric field that arises between oppositely charged atomic planes gives rise to a built-in potential that diverges with thickness. Here we present evidence of such a built-in potential across polar LaAlO{sub 3} thin films grown on SrTiO{sub 3} substrates, a system well known for the electron gas that forms a… more
Date: August 15, 2011
Creator: Guneeta, Singh-Bhalla
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Review of electrostatic plugging

Description: Using electric fields to diminish end losses from open magnetic plasma confinement systems is equivalent to magnetically shielding the grid wires of an electrostatic plasma confinement device. Electrostatically plugged magnetic cusps confine electrons magnetically in the perpendicular direction and electrostatically in the parallel direction, and ions are purely electrostatically confined in both directions. Theoretical estimates have been made of confinement times, electron density, plasma pot… more
Date: August 10, 1977
Creator: Dolan, T. J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Comparative Study of the Defect Point Physics and Luminescence of the Kesterites Cu2ZnSnS4 and Cu2ZnSnSe4 and Chalcopyrite Cu(In,Ga)Se2: Preprint

Description: In this contribution, we present a comparative study of the luminescence of the kesterites Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) and their related chalcopyrite Cu(In,Ga)Se2 (CIGSe). Luminescence spectroscopy suggests that the electronic properties of Zn-rich, Cu-poor kesterites (both CZTS and CZTSe) and Cu-poor CIGSe are dictated by fluctuations of the electrostatic and chemical potentials. The large redshift in the luminescence of grain boundaries in CIGSe, associated with the formation of a… more
Date: August 1, 2012
Creator: Romero, M. J.; Repins, I.; Teeter, G.; Contreras, M.; Al-Jassim, M. & Noufi, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Tuning the Electron Gas at an Oxide Heterointerface via Free Surface Charges

Description: Oxide heterointerfaces are emerging as one of the most exciting materials systems in condensed matter science. One remarkable example is the LaAlO{sub 3}/SrTiO{sub 3} (LAO/STO) interface, a model system in which a highly mobile electron gas forms between two band insulators, exhibiting two dimensional superconductivity and unusual magnetotransport properties. An ideal tool to tune such an electron gas is the electrostatic field effect. In principle, the electrostatic field can be generated by b… more
Date: August 11, 2011
Creator: Bell, Christopher
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Technical Challenges for the Head-on Collisions and Extraction at the ILC

Description: An interaction region with head-on collisions is considered as an alternative to the baseline ILC configuration. Progress in the final focus optics design includes engineered large bore superconducting final doublet magnets and their 3D magnetic integration in the detector solenoids. Progress on the beam separation optics is based on technical designs of electrostatic separator and special extraction quadrupoles. The spent beam extraction is realized by a staged collimation scheme relying on re… more
Date: August 14, 2007
Creator: Napoly, O.; Delferriere, O.; Durante, M.; Payet, J.; Rippon, C.; Uriot, D. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Design of an RFQ-Based Neutron Source for Cargo ContainerInterrogation

Description: An RFQ-based neutron generator system is described that produces pulsed neutrons for the active screening of sea-land cargo containers for the detection of shielded special nuclear materials (SNM).A microwave-driven deuteron source is coupled to an electrostatic LEBT that injects a 40 mA D+ beam into a 6 MeV, 5.1 meter-long 200 MHz RFQ.The RFQ has a unique beam dynamics design and is capable of operating at duty factors of 5 to 10 percent accelerating a D+ time-averaged current of up to 1.5 mA … more
Date: August 1, 2006
Creator: Staples, John W.; Hoff, M. D.; Kwan, J. W.; Li, D.; Ludewigt, B. A.; Ratti, A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Charge state dependence of cathodic vacuum arc ion energy andvelocity distributions

Description: In the literature, conflicting conclusions are reported concerning the charge state dependence of cathodic arc ion energy and velocity distributions. It appears that data from electrostatic energy analyzers indicate charge state dependence of ion energy, whereas time-of-flight methods support charge state independence of ion velocity. Here we present charge-state-resolved ion energy distributions and calculate the corresponding ion velocity distributions in aluminum vacuum arc plasma. We show t… more
Date: August 15, 2006
Creator: Rosen, Johanna; Schneider, Jochen M. & Anders, Andre
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Simulating Electron Clouds in High-Current Ion Accelerators with Solenoid Focusing

Description: Contamination from electrons is a concern for the solenoid-focused ion accelerators being developed for experiments in high-energy-density physics (HEDP). These electrons are produced directly by beam ions hitting lattice elements and intercepting diagnostics, or indirectly by ionization of desorbed neutral gas, and they are believed responsible for time dependence of the beam radius, emittance, and focal distance seen on the Solenoid Transport Experiment (STX) at Lawrence Berkeley National Lab… more
Date: August 15, 2006
Creator: Sharp, W.; Grote, D.; Cohen, R.; Friedman, A.; Vay, J.; Seidl, P. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Effectiveness of Electrostatic Shielding and Electronic Subtraction to Correct for the Hole Trapping in Cdznte Semiconductor Detectors.

Description: CdZnTe (CZT) is a very promising material for nuclear-radiation detectors. CZT detectors operate at ambient temperatures and offer high detection efficiency and excellent energy resolution, placing them ahead of high-purity Ge for those applications where cryogenic cooling is problematic. The progress achieved in CZT detectors over the past decade is founded on the developments of robust detector designs and readout electronics, both of which helped to overcome the effects of carrier trapping. … more
Date: August 26, 2007
Creator: Bolotnikov, A. E.; Camarda, G. S.; Hossain, A.; Cui, Y. & James, R. B.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Electron density measurement of an electrostatically-confined, spherically symmetric, helium plasma using a microwave cavity resonance shift technique

Description: Thesis. Microwave resonant cavity frequency shift measurements are made to determine the electron density of an electrostatically confined, spherically symmetric helium plasma. Appropriate electron-density distribution functions are assumed and then used to relate the frequency shift to the central electron density. Results from electron injection, with currents of up to 200 mA, accelerating voltages from 100 to 450 V, and pressures of 5.0, 1.0, and 0.5 mTorr, suggest that a potential well is f… more
Date: August 1, 1973
Creator: Grush, W H
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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Zirconium Hazards Research. Summary Report No. 3655 for September 1, 1956 to August 31, 1957

Description: The sensitivity characteristics of a variety of Zr samples such as sponge, scrap, powder and process materials were studicd. Of particular interest was the determination of the relative seasitivity of these materials to such stimuli as impact, friction, electrostatic discharge, and heat. A study of the zirconium--water reaction at relatively low temperature was initiated. In general, scrap and sponge were relatively insensitive to impact. Only one proeess material, the distillation residue, exh… more
Date: August 31, 1957
Creator: Herickes, J.A.; Richardson, P.A.; Weiss, M. & Gelernter, G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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OXIDE FLUORINATION TOWER

Description: A 3-inch-diameter flame tower for the conversion of uranosic oxide to uranium hexafluoride with elemental fluorine was tested for possible use in the fluorination step of the present uranium recovery process. The oxide was fed from a hopper to the tower by a screw feeder. The fluorine and the oxide entered at the top and flowed concurrently down through the tower. The unreacted or partially reacted oxide was collected in an ash receiver at the bottom. Fine solid particles were removed from the … more
Date: August 28, 1959
Creator: Peoples, L.C.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Be Foil "Filter Knee Imaging" NSTX Plasma with Fast Soft X-ray Camera

Description: A fast soft x-ray (SXR) pinhole camera has been implemented on the National Spherical Torus Experiment (NSTX). This paper presents observations and describes the Be foil Filter Knee Imaging (FKI) technique for reconstructions of a m/n=1/1 mode on NSTX. The SXR camera has a wide-angle (28{sup o}) field of view of the plasma. The camera images nearly the entire diameter of the plasma and a comparable region in the vertical direction. SXR photons pass through a beryllium foil and are imaged by a p… more
Date: August 8, 2005
Creator: Stratton, B. C.; Goeler, S. Von.; Stutman, D.; Tritz, K. & Zakharov, L.E.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Numerical Studies of Magnetohydrodynamic Activity Resulting from Inductive Transients Final Report

Description: This report describes results from numerical studies of transients in magnetically confined plasmas. The work has been performed by University of Wisconsin graduate students James Reynolds and Giovanni Cone and by the Principal Investigator through support from contract DE-FG02-02ER54687, a Junior Faculty in Plasma Science award from the DOE Office of Science. Results from the computations have added significantly to our knowledge of magnetized plasma relaxation in the reversed-field pinch (RFP… more
Date: August 29, 2005
Creator: Sovinec, Carl R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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