Sample records for dielectric wakefield accelerator

  1. Experimental Plans to Explore Dielectric Wakefield Acceleration in the THZ Regime

    SciTech Connect (OSTI)

    Lemery, F.; Mihalcea, D.; /Northern Illinois U.; Piot, P.; /Fermilab; Behrens, C.; Elsen, E.; Flottmann, K.; Gerth, C.; Kube, G.; Schmidt, B.; /DESY; Osterhoff, J.; /Hamburg U., Inst. Theor. Phys. II; Stoltz, P.

    2011-09-07T23:59:59.000Z

    Dielectric wakefield accelerators have shown great promise toward high-gradient acceleration. We investigate the performances of a possible experiment under consideration at the FLASH facility in DESY to explore wakefield acceleration with an enhanced transformer ratio. The experiment capitalizes on a unique pulse shaping capability recently demonstrated at this facility. In addition, the facility incorporates a superconducting linear accelerator that could generate bunch trains with closely spaced bunches thereby opening the exploration of potential dynamical effects in dielectric wakefield accelerators.

  2. Dielectric Wakefield Accelerator to drive the future FEL Light Source.

    SciTech Connect (OSTI)

    Jing, C.; Power, J.; Zholents, A. (Accelerator Systems Division (APS)); ( HEP); (LLC)

    2011-04-20T23:59:59.000Z

    X-ray free-electron lasers (FELs) are expensive instruments and a large part of the cost of the entire facility is driven by the accelerator. Using a high-energy gain dielectric wake-field accelerator (DWA) instead of the conventional accelerator may provide a significant cost saving and reduction of the facility size. In this article, we investigate using a collinear dielectric wakefield accelerator to provide a high repetition rate, high current, high energy beam to drive a future FEL x-ray light source. As an initial case study, a {approx}100 MV/m loaded gradient, 850 GHz quartz dielectric based 2-stage, wakefield accelerator is proposed to generate a main electron beam of 8 GeV, 50 pC/bunch, {approx}1.2 kA of peak current, 10 x 10 kHz (10 beamlines) in just 100 meters with the fill factor and beam loading considered. This scheme provides 10 parallel main beams with one 100 kHz drive beam. A drive-to-main beam efficiency {approx}38.5% can be achieved with an advanced transformer ratio enhancement technique. rf power dissipation in the structure is only 5 W/cm{sup 2} in the high repetition rate, high gradient operation mode, which is in the range of advanced water cooling capability. Details of study presented in the article include the overall layout, the transform ratio enhancement scheme used to increase the drive to main beam efficiency, main wakefield linac design, cooling of the structure, etc.

  3. A THz Coaxial Two-Channel Dielectric Wakefield Structure for High Gradient Acceleration

    SciTech Connect (OSTI)

    Marshall, T. C. [Columbia University, New York, NY (United States); Omega-P, Inc., New Haven, CT (United States); Sotnikov, G. V. [Omega-P, Inc., New Haven, CT (United States); NSC Kharkov Institute of Physics and Technology, Kharkov (Ukraine); Hirshfield, J. L. [Omega-P, Inc., New Haven, CT (United States); Yale University, New Haven, CT (United States)

    2010-11-04T23:59:59.000Z

    A coaxial two-channel dielectric wakefield structure is examined for use as a high gradient accelerator. A THz design, having radius {approx}1 mm, is shown to provide GeV/m--level acceleration gradient, high transformer ratio, and stable accelerated bunch motion when excited by a stable-moving 5-GeV 6-nC annular drive bunch.

  4. Numerical modeling of multi-GeV laser wakefield electron acceleration inside a dielectric capillary tube

    SciTech Connect (OSTI)

    Paradkar, B. S.; Cros, B.; Maynard, G. [Laboratoire de Physique des Gaz et des Plasmas, University Paris Sud 11-CNRS, Orsay (France)] [Laboratoire de Physique des Gaz et des Plasmas, University Paris Sud 11-CNRS, Orsay (France); Mora, P. [Centre de Physique Theorique, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France)] [Centre de Physique Theorique, CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France)

    2013-08-15T23:59:59.000Z

    Numerical modeling of laser wakefield electron acceleration inside a gas filled dielectric capillary tube is presented. Guiding of a short pulse laser inside a dielectric capillary tube over a long distance (?1 m) and acceleration of an externally injected electron bunch to ultra-relativistic energies (?5-10 GeV) are demonstrated in the quasi-linear regime of laser wakefield acceleration. Two dimensional axisymmetric simulations were performed with the code WAKE-EP (Extended Performances), which allows computationally efficient simulations of such long scale plasma. The code is an upgrade of the quasi-static particle code, WAKE [P. Mora and T. M. Antonsen, Jr., Phys. Plasmas 4, 217 (1997)], to simulate the acceleration of an externally injected electron bunch (including beam loading effect) and propagation of the laser beam inside a dielectric capillary. The influence of the transverse electric field of the plasma wake on the radial loss of the accelerated electrons to the dielectric wall is investigated. The stable acceleration of electrons to multi-GeV energy with a non-resonant laser pulse with a large spot-size is demonstrated.

  5. High Transformer ratios in collinear wakefield accelerators.

    SciTech Connect (OSTI)

    Power, J. G.; Conde, M.; Yusof, Z.; Gai, W.; Jing, C.; Kanreykin, A.; Schoessow, P.; High Energy Physics; Euclid Techlabs, LLC

    2008-01-01T23:59:59.000Z

    Based on our previous experiment that successfully demonstrated wakefield transformer ratio enhancement in a 13.625 GHz dielectric-loaded collinear wakefield accelerator using the ramped bunch train technique, we present here a redesigned experimental scheme for even higher enhancement of the efficiency of this accelerator. Design of a collinear wakefield device with a transformer ratio R2, is presented. Using a ramped bunch train (RBT) rather than a single drive bunch, the enhanced transformer ratio (ETR) technique is able to increase the transformer ratio R above the ordinary limit of 2. To match the wavelength of the fundamental mode of the wakefield with the bunch length (sigmaz=2 mm) of the new Argonne wakefield accelerator (AWA) drive gun (where the experiment will be performed), a 26.625 GHz dielectric based accelerating structure is required. This transformer ratio enhancement technique based on our dielectric-loaded waveguide design will result in a compact, high efficiency accelerating structures for future wakefield accelerators.

  6. Tomography of a laser wakefield accelerator Tomography of a laser wakefield accelerator

    E-Print Network [OSTI]

    history of laser-plasma accelerators is reviewed. The excitation of plasma waves by ultra-short laser Tomography of a laser wakefield accelerator Tomography of a laser wakefield accelerator 692220024 #12; Tomography of a laser wakefield accelerator i #12; Tomography of a laser

  7. Wakefield generation by a relativistic ring beam in a coaxial two channel dielectric loaded structure.

    SciTech Connect (OSTI)

    Liu, W.; Gai, W. (High Energy Physics)

    2009-05-12T23:59:59.000Z

    In this paper, we give a complete analytical solution for wakefields generated by an azimuthally symmetric ring beam propagating in a coaxial two-channel dielectric structure. This wakefield can be used to accelerate a witness beam in the central channel. The ratio of the peak accelerating field in the center channel to the decelerating field in the ring channel (defined as transformer ratio R) is also derived. We find that, by appropriate choice of parameters, R can be much greater than 2, the limiting value for collinear wakefield accelerators.

  8. High transformer ratio drive beams for wakefield accelerator studies

    SciTech Connect (OSTI)

    England, R. J.; Ng, C.-K.; Frederico, J.; Hogan, M. J.; Litos, M.; Muggli, P.; Joshi, C.; An, W.; Andonian, G.; Mori, W.; Lu, W. [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Max Planck Institute for Physics, 80805 Munich (Germany); University of California Los Angeles, Los Angeles, CA 90095 (United States); Tsinghua University, Beijing (China)

    2012-12-21T23:59:59.000Z

    For wakefield based acceleration schemes, use of an asymmetric (or linearly ramped) drive bunch current profile has been predicted to enhance the transformer ratio and generate large accelerating wakes. We discuss plans and initial results for producing such bunches using the 20 to 23 GeV electron beam at the FACET facility at SLAC National Accelerator Laboratory and sending them through plasmas and dielectric tubes to generate transformer ratios greater than 2 (the limit for symmetric bunches). The scheme proposed utilizes the final FACET chicane compressor and transverse collimation to shape the longitudinal phase space of the beam.

  9. Observation of Enhanced Transformer Ratio in Collinear Wakefield Acceleration

    SciTech Connect (OSTI)

    Jing, C.; Kanareykin, A. [Euclid Techlabs, LLC, Solon, OH-44139 (United States); Power, J.; Conde, M.; Yusof, Z.; Gai, W. [High Energy Physics Division, Argonne National Laboratory, Argonne, IL-60439 (United States)

    2006-11-27T23:59:59.000Z

    The transformer ratio R is a parameter that characterizes the efficiency of the energy transferred from the drive beam to the trailing witness beam passing through a wakefield accelerating structure (all metal or dielectric based) or a plasma chamber. Using a ramped bunch train (RBT) rather than a single drive bunch, the enhanced transformer ratio (ETR) technique is able to increase the transformer ratio R above the ordinary limit of 2 for a single bunch in a collinear wakefield accelerator. The RBT is a train of electron bunches separated by half integer multiples wavelength of the wakefield. The charge of the leading bunch is lowest and subsequent bunch charges are increased in such a way as to maximize R. In this article, an experimental study of this scheme is presented in which an RBT of 2 bunches with charge ratio of 1:2.5 and bunch length {sigma}z = 2 mm were used to enhance the transformer ratio. Measurement results and data analysis show good agreement with theoretical predictions. The ETR technique demonstrated here can be used in any collinear wakefield accelerator configuration, either structure- or plasma-based.

  10. Observation of enhanced transformer ratio in collinear Wakefield acceleration.

    SciTech Connect (OSTI)

    Power, J.; Conde, M.; Yusof, Z.; Gai, W.; Jing, C.; Kanareykin, A.; High Energy Physics; Euclid Techlabs, LLC

    2006-01-01T23:59:59.000Z

    The transformer ratio R is a parameter that characterizes the efficiency of the energy transferred from the drive beam to the trailing witness beam passing through a wakefield accelerating structure (all metal or dielectric based) or a plasma chamber. Using a ramped bunch train (RBT) rather than a single drive bunch, the enhanced transformer ratio (ETR) technique is able to increase the transformer ratio R above the ordinary limit of 2 for a single bunch in a collinear wakefield accelerator. The RBT is a train of electron bunches separated by half integer multiples wavelength of the wakefield. The charge of the leading bunch is lowest and subsequent bunch charges are increased in such a way as to maximize R. In this article, an experimental study of this scheme is presented in which an RBT of 2 bunches with charge ratio of 1:2.5 and bunch length {sigma}{sub z} = 2 mm were used to enhance the transformer ratio. Measurement results and data analysis show good agreement with theoretical predictions. The ETR technique demonstrated here can be used in any collinear wakefield accelerator configuration, either structure- or plasma-based.

  11. Current Filamentation Instability in Laser Wakefield Accelerators

    SciTech Connect (OSTI)

    Huntington, C. M.; Drake, R. P. [Atmospheric, Oceanic and Space Science, University of Michigan, Ann Arbor, Michigan, 48103 (United States); Thomas, A. G. R.; McGuffey, C.; Matsuoka, T.; Chvykov, V.; Kalintchenko, G.; Yanovsky, V.; Maksimchuk, A.; Krushelnick, K. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Kneip, S.; Najmudin, Z.; Palmer, C. [Blackett Laboratory, Imperial College London, London, SW7 2BZ (United Kingdom); Katsouleas, T. [Platt School of Engineering, Duke University, Durham, North Carolina, 27708 (United States)

    2011-03-11T23:59:59.000Z

    Experiments using an electron beam produced by laser-wakefield acceleration have shown that varying the overall beam-plasma interaction length results in current filamentation at lengths that exceed the laser depletion length in the plasma. Three-dimensional simulations show this to be a combination of hosing, beam erosion, and filamentation of the decelerated beam. This work suggests the ability to perform scaled experiments of astrophysical instabilities. Additionally, understanding the processes involved with electron beam propagation is essential to the development of wakefield accelerator applications.

  12. GeV electrons due to a transition from laser wakefield acceleration to plasma wakefield acceleration

    E-Print Network [OSTI]

    P. E. Masson-Laborde; M. Z. Mo; A. Ali; S. Fourmaux; P. Lassonde; J. C. Kieffer; W. Rozmus; D. Teychenne; R. Fedosejevs

    2014-08-06T23:59:59.000Z

    We show through experiments that a transition from laser wakefield acceleration (LWFA) regime to a plasma wakefield acceleration (PWFA) regime can drive electrons up to energies close to the GeV level. Initially, the acceleration mechanism is dominated by the bubble created by the laser in the nonlinear regime of LWFA, leading to an injection of a large number of electrons. After propagation beyond the depletion length, leading to a depletion of the laser pulse, whose transverse ponderomotive force is not able to sustain the bubble anymore, the high energy dense bunch of electrons propagating inside bubble will drive its own wakefield by a PWFA regime. This wakefield will be able to trap and accelerate a population of electrons up to the GeV level during this second stage. Three dimensional (3D) particle-in-cell (PIC) simulations support this analysis, and confirm the scenario.

  13. Observation of Enhanced Transformer Ratio in Collinear Wakefield Acceleration

    SciTech Connect (OSTI)

    Jing, C.; Kanareykin, A.; Schoessow, P. [Euclid Techlabs LLC, Solon, Ohio 44139 (United States); Power, J. G.; Conde, M.; Yusof, Z.; Gai, W. [High Energy Physics Division, Argonne National Laboratory, Argonne, Illinois-60439 (United States)

    2007-04-06T23:59:59.000Z

    One approach to future high energy particle accelerators is based on the wakefield principle: a leading high-charge drive bunch is used to excite fields in an accelerating structure or plasma that in turn accelerates a trailing low-charge witness bunch. The transformer ratio R is defined as the ratio of the maximum energy gain of the witness bunch to the maximum energy loss of the drive bunch. In general, R<2 for this configuration. A number of techniques have been proposed to overcome the transformer ratio limitation. We report here the first experimental study of the ramped bunch train (RBT) technique in a dielectric based accelerating structure. A single drive bunch was replaced by two bunches with charge ratio of 1 ratio 2.5 and a separation of 10.5 wavelengths of the fundamental mode. An average measured transformer ratio enhancement by a factor of 1.31 over the single drive bunch case was obtained.

  14. Laser wakefield simulations towards development of compact particle accelerators

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Laser wakefield simulations towards development of compact particle accelerators C.G.R. Geddes1, D understanding of accelerator physics to advance beam performance and stability, and particle simulations model, France; 9 Oxford University, UK E-mail: cgrgeddes@lbl.gov Abstract. Laser driven wakefield accelerators

  15. Laser Guiding at Relativistic Intensities and Wakefield Particle Acceleration

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Laser Guiding at Relativistic Intensities and Wakefield Particle Acceleration in Plasma Channels C for the first time in a high gradient laser wakefield accelerator by guiding the drive laser pulse. Channels formed by hydrodynamic shock were used to guide acceleration relevant laser intensities of at least 1E18

  16. COAXIAL TWO-CHANNEL DIELECTRIC WAKE FIELD ACCELERATOR

    SciTech Connect (OSTI)

    Hirshfield, Jay L. [Omega-P, Inc.

    2013-04-30T23:59:59.000Z

    Theory, computations, and experimental apparatus are presented that describe and are intended to confirm novel properties of a coaxial two-channel dielectric wake field accelerator. In this configuration, an annular drive beam in the outer coaxial channel excites multimode wakefields which, in the inner channel, can accelerate a test beam to an energy much higher than the energy of the drive beam. This high transformer ratio is the result of judicious choice of the dielectric structure parameters, and of the phase separation between drive bunches and test bunches. A structure with cm-scale wakefields has been build for tests at the Argonne Wakefield Accelerator Laboratory, and a structure with mm-scale wakefields has been built for tests at the SLAC FACET facility. Both tests await scheduling by the respective facilities.

  17. TWO-CHANNEL DIELECTRIC WAKE FIELD ACCELERATOR

    SciTech Connect (OSTI)

    Jay L. Hirshfield

    2012-05-30T23:59:59.000Z

    Experimental results are reported for test beam acceleration and deflection in a two-channel, cm-scale, rectangular dielectric-lined wakefield accelerator structure energized by a 14-MeV drive beam. The dominant waveguide mode of the structure is at {approx}30 GHz, and the structure is configured to exhibit a high transformer ratio ({approx}12:1). Accelerated bunches in the narrow secondary channel of the structure are continuously energized via Cherenkov radiation that is emitted by a drive bunch moving in the wider primary channel. Observed energy gains and losses, transverse deflections, and changes in the test bunch charge distribution compare favorably with predictions of theory.

  18. Automatic beam path analysis of laser wakefield particle acceleration data

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Automatic beam path analysis of laser wakefield particle acceleration data Oliver Rübel1 particle accelerators play a key role in the understanding of the complex acceleration process in a pipeline fashion to automatically locate and analyze high-energy particle bunches undergoing acceleration

  19. Automatic Beam Path Analysis of Laser Wakefield Particle Acceleration Data

    E-Print Network [OSTI]

    Knowles, David William

    Automatic Beam Path Analysis of Laser Wakefield Particle Acceleration Data Oliver R¨ubel1 particle accelerators play a key role in the understanding of the complex acceleration process in a pipeline fashion to automatically locate and analyze high energy particle bunches undergoing acceleration

  20. Two Channel Dielectric-Lined Rectangular High Transformer Ratio Accelerator Structure Experiment

    SciTech Connect (OSTI)

    Shchelkunov, S. V.; LaPointe, M. A. [Beam Physics Laboratory, Yale University, 272 Whitney Avenue, New Haven, CT 06511 (United States); Hirshfield, J. L. [Beam Physics Laboratory, Yale University, 272 Whitney Avenue, New Haven, CT 06511 (United States); Omega-P, Inc., 258 Bradley St., New Haven, CT 06510 (United States); Marshall, T. C. [Columbia University, New York, NY 10027 (United States); Omega-P, Inc., 258 Bradley St., New Haven, CT 06510 (United States); Sotnikov, G. [NSC Kharkov Institute of Physics and Technology, Kharkov (Ukraine); Omega-P, Inc., 258 Bradley St., New Haven, CT 06510 (United States); Gai, Wei; Conde, M.; Power, J.; Mihalcea, D. [Argonne National Laboratory, Argonne, IL 60439 (United States)

    2010-11-04T23:59:59.000Z

    Current status of a two-channel cm-scale rectangular dielectric lined wakefield accelerator structure is described. This structure is installed at the Argonne Wakefield Accelerator facility (AWA), and is presently being evaluated. The device has a transformer ratio of {approx}12.5:1. When driven by a {approx}50 nC single drive bunch it is expected to obtain {approx}6 MV/m acceleration gradient. Related issues are discussed.

  1. Cast dielectric composite linear accelerator

    DOE Patents [OSTI]

    Sanders, David M. (Livermore, CA); Sampayan, Stephen (Manteca, CA); Slenes, Kirk (Albuquerque, NM); Stoller, H. M. (Albuquerque, NM)

    2009-11-10T23:59:59.000Z

    A linear accelerator having cast dielectric composite layers integrally formed with conductor electrodes in a solventless fabrication process, with the cast dielectric composite preferably having a nanoparticle filler in an organic polymer such as a thermosetting resin. By incorporating this cast dielectric composite the dielectric constant of critical insulating layers of the transmission lines of the accelerator are increased while simultaneously maintaining high dielectric strengths for the accelerator.

  2. Plasma Wakefield Acceleration for Ultrahigh Energy Cosmic Rays

    E-Print Network [OSTI]

    Pisin Chen; Toshiki Tajima; Yoshiyuki Takahashi

    2002-05-21T23:59:59.000Z

    A cosmic acceleration mechanism is introduced which is based on the wakefields excited by the Alfven shocks in a relativistically flowing plasma, where the energy gain per distance of a test particle is Lorentz invariant. We show that there exists a threshold condition for transparency below which the accelerating particle is collision-free and suffers little energy loss in the plasma medium. The stochastic encounters of the random accelerating-decelerating phases results in a power-law energy spectrum: f(e) 1/e^2. The environment suitable for such plasma wakefield acceleration can be cosmically abundant. As an example, we discuss the possible production of super-GZK ultra high energy cosmic rays (UHECR) through this mechanism in the atmosphere of gamma ray bursts. We show that the acceleration gradient can be as high as G ~ 10^16 eV/cm. The estimated event rate in our model agrees with that from UHECR observations.

  3. THE DIELECTRIC WALL ACCELERATOR

    SciTech Connect (OSTI)

    Caporaso, G J; Chen, Y; Sampayan, S E

    2009-08-17T23:59:59.000Z

    The Dielectric Wall Accelerator (DWA), a class of induction accelerators, employs a novel insulating beam tube to impress a longitudinal electric field on a bunch of charged particles. The surface flashover characteristics of this tube may permit the attainment of accelerating gradients on the order of 100 MV/m for accelerating pulses on the order of a nanosecond in duration. A virtual traveling wave of excitation along the tube is produced at any desired speed by controlling the timing of pulse generating modules that supply a tangential electric field to the tube wall. Because of the ability to control the speed of this virtual wave, the accelerator is capable of handling any charge to mass ratio particle; hence it can be used for electrons, protons and any ion. The accelerator architectures, key technologies and development challenges will be described.

  4. Proof-of-principle experiments of laser Wakefield acceleration

    SciTech Connect (OSTI)

    Nakajima, K.; Kawakubo, T.; Nakanishi, H. [National Lab. for Higher Energy Physics, Ibaraki (Japan)] [and others

    1994-04-01T23:59:59.000Z

    Recently there has been a great interest in laser-plasma accelerators as possible next-generation particle accelerators because of their potential for ultra high accelerating gradients and compact size compared with conventional accelerators. It is known that the laser pulse is capable of exciting a plasma wave propagating at a phase velocity close to the velocity of light by means of beating two-frequency lasers or an ultra short laser pulse. These schemes came to be known as the Beat Wave Accelerator (BWA) for beating lasers or as the Laser Wakefield Accelerator (LWFA) for a short pulse laser. In this paper, the principle of laser wakefield particle acceleration has been tested by the Nd:glass laser system providing a short pulse with a power of 10 TW and a duration of 1 ps. Electrons accelerated up to 18 MeV/c have been observed by injecting 1 MeV/c electrons emitted from a solid target by an intense laser impact. The accelerating field gradient of 30 GeV/m is inferred.

  5. Stern-Gerlach surfing in laser wakefield accelerators

    E-Print Network [OSTI]

    Flood, Stephen P

    2015-01-01T23:59:59.000Z

    We investigate the effects of a Stern-Gerlach-type addition to the Lorentz force on electrons in a laser wakefield accelerator. The Stern-Gerlach-type terms are found to generate a family of trajectories describing electrons that surf along the plasma density wave driven by a laser pulse. Such trajectories could lead to an increase in the size of an electron bunch, which may have implications for attempts to exploit such bunches in future free electron lasers.

  6. Plasma Wakefield Acceleration and FACET - Facilities for Accelerator Science and Experimental Test Beams at SLAC

    ScienceCinema (OSTI)

    Andrei Seryi

    2010-01-08T23:59:59.000Z

    Plasma wakefield acceleration is one of the most promising approaches to advancing accelerator technology. This approach offers a potential 1,000-fold or more increase in acceleration over a given distance, compared to existing accelerators.  FACET, enabled by the Recovery Act funds, will study plasma acceleration, using short, intense pulses of electrons and positrons. In this lecture, the physics of plasma acceleration and features of FACET will be presented.  

  7. Plasma Wakefield Acceleration: How it Works

    SciTech Connect (OSTI)

    None

    2014-11-05T23:59:59.000Z

    This animation explains how electrons can be efficiently accelerated to high energy using wakes created in a plasma.

  8. Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle Cormier-Michel,1,2

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Unphysical kinetic effects in particle-in-cell modeling of laser wakefield accelerators Estelle of laser wakefield accelerators using particle-in-cell codes are investigated. A dark current free laser wakefield accelerator stage, in which no trapping of background plasma electrons into the plasma wave should

  9. Application of High-performance Visual Analysis Methods to Laser Wakefield Particle Acceleration Data

    E-Print Network [OSTI]

    Application of High-performance Visual Analysis Methods to Laser Wakefield Particle Acceleration, time- varying laser wakefield particle accelerator simulation data. We ex- tend histogramBit, a state-of-the-art index/query technology, to acceler- ate data mining and multi-dimensional histogram

  10. Multimode Analysis of the Hollow Plasma Channel Wakefield Accelerator C. B. Schroeder,1

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    by resonant excitation [1]. In conventional accelerators, the size of these accel- erating fields is limited particle beam. For the laser wakefield accelerator one of the most se- vere limitations is the weakening- neous plasma. These properties make it well suited as a structure for both particle beam wakefield

  11. RECENT PROGRESS AT LBNL ON CHARACTERIZATION OF LASER WAKEFIELD ACCELERATED ELECTRON BUNCHES USING

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    RECENT PROGRESS AT LBNL ON CHARACTERIZATION OF LASER WAKEFIELD ACCELERATED ELECTRON BUNCHES USING. Schroeder, J. van Tilborg, Cs. T´oth Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA 94720, USA Abstract At LBNL, laser wakefield accelerators (LWFA) can now produce ultra-short electron bunches

  12. Benchmarking the codes VORPAL, OSIRIS, and QuickPIC with Laser Wakefield Acceleration

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    with ultra-short Ti-Sapphire laser pulses propagating in hydrogen gas. Both first-order and secondBenchmarking the codes VORPAL, OSIRIS, and QuickPIC with Laser Wakefield Acceleration Simulations K Técnico, Lisboa, Portugal Abstract. Three-dimensional laser wakefield acceleration (LWFA) simulations have

  13. Beyond injection: Trojan horse underdense photocathode plasma wakefield acceleration

    SciTech Connect (OSTI)

    Hidding, B.; Rosenzweig, J. B.; Xi, Y.; O'Shea, B.; Andonian, G.; Schiller, D.; Barber, S.; Williams, O.; Pretzler, G.; Koenigstein, T.; Kleeschulte, F.; Hogan, M. J.; Litos, M.; Corde, S.; White, W. W.; Muggli, P.; Bruhwiler, D. L.; Lotov, K. [Institut fuer Laser- und Plasmaphysik, Heinrich-Heine-Universitaet Duesseldorf 40225 Duesseldorf (Germany) and Particle Beam Physics Laboratory, Department for Physics and Astronomy, UCLA (United States); Particle Beam Physics Laboratory, Department for Physics and Astronomy, UCLA (United States); Institut fuer Laser- und Plasmaphysik, Heinrich-Heine-Universitaet Duesseldorf 40225 Duesseldorf (Germany); Stanford Linear Accelerator Center (United States); Max-Planck-Institut fuer Physik, Muenchen (Germany); Tech-X Corporation, Boulder, Colorado (United States) and 1348 Redwood Ave., Boulder, Colorado 80304 (United States); Budker Institute of Nuclear Physics SB RAS, 630090, Novosibirsk (Russian Federation) and Novosibirsk State University, 630090, Novosibirsk (Russian Federation)

    2012-12-21T23:59:59.000Z

    An overview on the underlying principles of the hybrid plasma wakefield acceleration scheme dubbed 'Trojan Horse' acceleration is given. The concept is based on laser-controlled release of electrons directly into a particle-beam-driven plasma blowout, paving the way for controlled, shapeable electron bunches with ultralow emittance and ultrahigh brightness. Combining the virtues of a low-ionization-threshold underdense photocathode with the GV/m-scale electric fields of a practically dephasing-free beam-driven plasma blowout, this constitutes a 4th generation electron acceleration scheme. It is applicable as a beam brightness transformer for electron bunches from LWFA and PWFA systems alike. At FACET, the proof-of-concept experiment 'E-210: Trojan Horse Plasma Wakefield Acceleration' has recently been approved and is in preparation. At the same time, various LWFA facilities are currently considered to host experiments aiming at stabilizing and boosting the electron bunch output quality via a trojan horse afterburner stage. Since normalized emittance and brightness can be improved by many orders of magnitude, the scheme is an ideal candidate for light sources such as free-electron-lasers and those based on Thomson scattering and betatron radiation alike.

  14. Increasing the transformer ratio at the Argonne wakefield accelerator.

    SciTech Connect (OSTI)

    Power, J.G.; Conde, M.; Liu, W.; Yusof, Z.; Gai, W.; Jing, C.; Kanareykin, A. (High Energy Physics); (Euclid Techlabs, LLC)

    2011-01-01T23:59:59.000Z

    The transformer ratio is defined as the ratio of the maximum energy gain of the witness bunch to the maximum energy loss experienced by the drive bunch (or a bunch within a multidrive bunch train). This plays an important role in the collinear wakefield acceleration scheme. A high transformer ratio is desirable since it leads to a higher overall efficiency under similar conditions (e.g. the same beam loading, the same structure, etc.). One technique to enhance the transformer ratio beyond the ordinary limit of 2 is to use a ramped bunch train. The first experimental demonstration observed a transformer ratio only marginally above 2 due to the mismatch between the drive microbunch length and the frequency of the accelerating structure [C. Jing, A. Kanareykin, J. Power, M. Conde, Z. Yusof, P. Schoessow, and W. Gai, Phys. Rev. Lett. 98, 144801 (2007)]. Recently, we revisited this experiment with an optimized microbunch length using a UV laser stacking technique at the Argonne Wakefield Accelerator facility and measured a transformer ratio of 3.4. Measurements and data analysis from these experiments are presented in detail.

  15. Beam Head Erosion in Self-Ionized Plasma Wakefield Accelerators

    SciTech Connect (OSTI)

    Berry, M.K.; Blumenfeld, I.; Decker, F.J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.H.; Kirby, N.A.; Siemann, Robert H.; Walz, D.R.; /SLAC; Clayton, C.E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; /UCLA; Katsouleas, T.C.; Muggli, P.; Oz, E.; /Southern California U.

    2008-01-28T23:59:59.000Z

    In the recent plasma wakefield accelerator experiments at SLAC, the energy of the particles in the tail of the 42 GeV electron beam were doubled in less than one meter [1]. Simulations suggest that the acceleration length was limited by a new phenomenon--beam head erosion in self-ionized plasmas. In vacuum, a particle beam expands transversely in a distance given by {beta}*. In the blowout regime of a plasma wakefield [2], the majority of the beam is focused by the ion channel, while the beam head slowly spreads since it takes a finite time for the ion channel to form. It is observed that in self-ionized plasmas, the head spreading is exacerbated compared to that in pre-ionized plasmas, causing the ionization front to move backward (erode). A simple theoretical model is used to estimate the upper limit of the erosion rate for a bi-gaussian beam by assuming free expansion of the beam head before the ionization front. Comparison with simulations suggests that half this maximum value can serve as an estimate for the erosion rate. Critical parameters to the erosion rate are discussed.

  16. EXPERIMENTAL RESULTS OF A PLASMA WAKEFIELD ACCELERATOR USING MULTIPLE ELECTRON BUNCHES

    E-Print Network [OSTI]

    Brookhaven National Laboratory

    ) of the Brookhaven National Laboratory (BNL). We have observed increasing energy loss along the length of the beam preliminary experimental results of a plasma wakefield accelerator technique which utilizes multiple electron oscillations that can support electric fields (wakefields) that can be orders of magnitude higher than those

  17. Wakefield Damping in a Pair of X-Band Accelerators for Linear Colliders

    SciTech Connect (OSTI)

    Jones, R.M.; Adolphsen, C.E.; Wang, J.W.; Li, Z.; /SLAC

    2006-12-18T23:59:59.000Z

    We consider means to damp the wake-field left behind ultra-relativistic charges. In particular, we focus on a pair of travelling wave accelerators operating at an X-band frequency of 11.424 GHz. In order to maximize the efficiency of acceleration, in the context of a linear collider, multiple bunches of charged particles are accelerated within a given pulse of the electromagnetic field. The wake-field left behind successive bunches, if left unchecked, can seriously disturb the progress of trailing bunches and can lead to an appreciable dilution in the emittance of the beam. We report on a method to minimize the influence of the wake-field on trailing bunches. This method entails detuning the characteristic mode frequencies which make-up the electromagnetic field, damping the wake-field, and interleaving the frequencies of adjacent accelerating structures. Theoretical predictions of the wake-field and modes, based on a circuit model, are compared with experimental measurements of the wake-field conducted within the ASSET facility at SLAC. Very good agreement is obtained between theory and experiment and this allows us to have some confidence in designing the damping of wake-fields in a future linear collider consisting of several thousand of these accelerating structures.

  18. Calculation of wakefields in a 17 GHz beam-driven photonic band-gap accelerator structure

    E-Print Network [OSTI]

    Hu, Min

    We present the theoretical analysis and computer simulation of the wakefields in a 17 GHz photonic band-gap (PBG) structure for accelerator applications. Using the commercial code CST Particle Studio, the fundamental ...

  19. Measurement of wakefields generated in accelerator test structures using the SLC

    SciTech Connect (OSTI)

    Adolphsen, C.; Bane, K.; Loew, G.; Ruth, R.; Thompson, K.; Wang, J.

    1992-10-01T23:59:59.000Z

    Research is underway at SLAC to develop accelerator structures for the next generation linear collider. An important feature of the design is a detuning of the dipole modes of the cells to suppress the long-range transverse wakefield by two orders of magnitude. This paper describes a facility, called ASSET, that will be incorporated into the SLAC Linear Collider (SLC) to test the long-range wakefield suppression and also to measure the other components of the wakefields generated in accelerator test structures.

  20. A proposal for a 1 GeV plasma-wakefield acceleration experiment at SLAC

    SciTech Connect (OSTI)

    Katsouleas, T.; Lee, S. [Univ. of Southern California, Los Angeles, CA (United States); Assmann, R. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)] [and others

    1997-07-01T23:59:59.000Z

    A plasma-based wakefield acceleration (PWFA) experiment is proposed that will accelerate parts of an SLC bunch by up to 1 GeV/m over a length of 1 m. A single SLC bunch is used to both induce wakefields in the one meter long plasma and to witness the resulting beam acceleration. The proposed experiment will explore and further develop the techniques that are needed to apply high-gradient plasma wakefield acceleration to large scale accelerators. The one meter length of the experiment is about two orders of magnitude larger than other high-gradient PWFA experiments and the 1 GeV/m accelerating gradient is roughly ten times larger than that achieved with conventional metallic structures. Using existing SLAC facilities, the proposed experiment will allow the study of high-gradient acceleration at the forefront of advanced accelerator research.

  1. Automatic Beam Path Analysis of Laser Wakefield Particle Acceleration Data

    SciTech Connect (OSTI)

    Rubel, Oliver; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Wu, Kesheng; Prabhat,; Weber, Gunther H.; Ushizima, Daniela M.; Messmer, Peter; Hagen, Hans; Hamann, Bernd; Bethel, E. Wes

    2009-10-19T23:59:59.000Z

    Numerical simulations of laser wakefield particle accelerators play a key role in the understanding of the complex acceleration process and in the design of expensive experimental facilities. As the size and complexity of simulation output grows, an increasingly acute challenge is the practical need for computational techniques that aid in scientific knowledge discovery. To that end, we present a set of data-understanding algorithms that work in concert in a pipeline fashion to automatically locate and analyze high energy particle bunches undergoing acceleration in very large simulation datasets. These techniques work cooperatively by first identifying features of interest in individual timesteps, then integrating features across timesteps, and based on the information derived perform analysis of temporally dynamic features. This combination of techniques supports accurate detection of particle beams enabling a deeper level of scientific understanding of physical phenomena than hasbeen possible before. By combining efficient data analysis algorithms and state-of-the-art data management we enable high-performance analysis of extremely large particle datasets in 3D. We demonstrate the usefulness of our methods for a variety of 2D and 3D datasets and discuss the performance of our analysis pipeline.

  2. Properties of Trapped Electron Bunches in a Plasma Wakefield Accelerator

    SciTech Connect (OSTI)

    Kirby, Neil; /SLAC

    2009-10-30T23:59:59.000Z

    Plasma-based accelerators use the propagation of a drive bunch through plasma to create large electric fields. Recent plasma wakefield accelerator (PWFA) experiments, carried out at the Stanford Linear Accelerator Center (SLAC), successfully doubled the energy for some of the 42 GeV drive bunch electrons in less than a meter; this feat would have required 3 km in the SLAC linac. This dissertation covers one phenomenon associated with the PWFA, electron trapping. Recently it was shown that PWFAs, operated in the nonlinear bubble regime, can trap electrons that are released by ionization inside the plasma wake and accelerate them to high energies. These trapped electrons occupy and can degrade the accelerating portion of the plasma wake, so it is important to understand their origins and how to remove them. Here, the onset of electron trapping is connected to the drive bunch properties. Additionally, the trapped electron bunches are observed with normalized transverse emittance divided by peak current, {epsilon}{sub N,x}/I{sub t}, below the level of 0.2 {micro}m/kA. A theoretical model of the trapped electron emittance, developed here, indicates that the emittance scales inversely with the square root of the plasma density in the non-linear 'bubble' regime of the PWFA. This model and simulations indicate that the observed values of {epsilon}{sub N,x}/I{sub t} result from multi-GeV trapped electron bunches with emittances of a few {micro}m and multi-kA peak currents. These properties make the trapped electrons a possible particle source for next generation light sources. This dissertation is organized as follows. The first chapter is an overview of the PWFA, which includes a review of the accelerating and focusing fields and a survey of the remaining issues for a plasma-based particle collider. Then, the second chapter examines the physics of electron trapping in the PWFA. The third chapter uses theory and simulations to analyze the properties of the trapped electron bunches. Chapters four and five present the experimental diagnostics and measurements for the trapped electrons. Next, the sixth chapter introduces suggestions for future trapped electron experiments. Then, Chapter seven contains the conclusions. In addition, there is an appendix chapter that covers a topic which is extraneous to electron trapping, but relevant to the PWFA. This chapter explores the feasibility of one idea for the production of a hollow channel plasma, which if produced could solve some of the remaining issues for a plasma-based collider.

  3. EXPERIMENTAL DEMONSTRATION OF WAKEFIELD EFFECTS IN A 250 GHZ PLANAR DIAMOND ACCELERATING STRUCTURE*

    E-Print Network [OSTI]

    Brookhaven National Laboratory

    of a rectangular waveguide loaded with polycrystalline CVD diamond plates as an accelerating structure. It should polycrystalline diamond plates loaded in a 6 cm long waveguide (Fig. 2). The beam gap was 200 microns (Fig. TM11EXPERIMENTAL DEMONSTRATION OF WAKEFIELD EFFECTS IN A 250 GHZ PLANAR DIAMOND ACCELERATING STRUCTURE

  4. Virtual gap dielectric wall accelerator

    DOE Patents [OSTI]

    Caporaso, George James; Chen, Yu-Jiuan; Nelson, Scott; Sullivan, Jim; Hawkins, Steven A

    2013-11-05T23:59:59.000Z

    A virtual, moving accelerating gap is formed along an insulating tube in a dielectric wall accelerator (DWA) by locally controlling the conductivity of the tube. Localized voltage concentration is thus achieved by sequential activation of a variable resistive tube or stalk down the axis of an inductive voltage adder, producing a "virtual" traveling wave along the tube. The tube conductivity can be controlled at a desired location, which can be moved at a desired rate, by light illumination, or by photoconductive switches, or by other means. As a result, an impressed voltage along the tube appears predominantly over a local region, the virtual gap. By making the length of the tube large in comparison to the virtual gap length, the effective gain of the accelerator can be made very large.

  5. Measurement of wakefield suppression in a detuned x-band accelerator structure

    SciTech Connect (OSTI)

    Adolphsen, C.; Bane, K.; Higo, T.; Kubo, K.; Miller, R.; Ruth, R.; Thompson, K.; Wang, J.

    1994-08-01T23:59:59.000Z

    Research is underway at SLAC to develop accelerator structures for a next generation linear collider. A full-scale prototype X-band structure has been built in which the dipole mode frequencies were detuned to suppress the long-range transverse wakefield by about two orders of magnitude. To verify that the detuning works as expected, a facility to measure the long-range wakefield, called the Accelerator Structure SETup, or ASSET, was constructed in the SLAC Linear Collider (SLC). This paper presents the results from the measurement of the prototype X-band structure with this facility.

  6. Role of stochastic heating in wakefield acceleration when optical injection is used

    SciTech Connect (OSTI)

    Rassou, S.; Bourdier, A.; Drouin, M. [CEA, DAM, DIF, 91297 Arpajon (France)

    2014-08-15T23:59:59.000Z

    The dynamics of an electron in two counterpropagating waves is investigated. Conditions for stochastic acceleration are derived. The possibility of stochastic heating is confirmed when two waves interact with low density plasma by performing PIC (Particle In Cell) code simulations. It is shown that stochastic heating can play an important role in laser wakefield acceleration. When considering low density plasma interacting with a high intensity wave perturbed by a low intensity counterpropagating wave, stochastic heating can provide electrons with the right momentum for trapping in the wakefield. The influence of stochastic acceleration on the trapping of electrons is compared to the one of the beatwave force which is responsible for cold injection. To do so, several polarizations for the colliding pulses are considered. For some value of the plasma density and pulse duration, a transition from an injection due to stochastic acceleration to a cold injection dominated regime—regarding the trapped charge—has been observed from 2D and 3D PIC code simulations. This transition is ruled by the ratio of the interaction length of the pulses to the longitudinal size of the bubble. When the interaction length of the laser pulses reaches the radius of the accelerating cavity stochastic heating becomes dominant, and might be necessary to get electrons trapped into the wakefield, when wakefield inhibition grows with plasma density.

  7. Visual Exploration of Turbulent Combustion and Laser-Wakefield Accelerator Simulations

    E-Print Network [OSTI]

    hydrogen flames under different levels of turbulence ­ Lean combustion reduces emissions Important hydrogen flames] #12;Visual Exploration of Turbulent Combustion and Laser-Wakefield Accelerator Simulations 12 Tracking Graph Extraction Pipeline 1. Concatenate to obtain 4D mesh 2. Extract isotherm in 4D 3

  8. Generation of electron beams from a laser wakefield acceleration in pure neon gas

    SciTech Connect (OSTI)

    Li, Song; Hafz, Nasr A. M., E-mail: nasr@sjtu.edu.cn; Mirzaie, Mohammad; Elsied, Ahmed M. M.; Ge, Xulei; Liu, Feng; Sokollik, Thomas; Chen, Min; Sheng, Zhengming; Zhang, Jie, E-mail: jzhang1@sjtu.edu.cn [Key Laboratory for Laser Plasmas (MOE) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Tao, Mengze; Chen, Liming [Bejing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-08-15T23:59:59.000Z

    We report on the generation of quasimonoenergetic electron beams by the laser wakefield acceleration of 17–50 TW, 30 fs laser pulses in pure neon gas jet. The generated beams have energies in the range 40–120?MeV and up to ?430 pC of charge. At a relatively high density, we observed multiple electron beamlets which has been interpreted by simulations to be the result of breakup of the laser pulse into multiple filaments in the plasma. Each filament drives its own wakefield and generates its own electron beamlet.

  9. Scaling of the Longitudinal Electric Field and Transformer Ratio in a Nonlinear Plasma Wakefield Accelerator

    SciTech Connect (OSTI)

    Blumenfeld, I.; /SLAC; Clayton, C.E.; /UCLA; Decker, F.J.; Hogan, M.J.; /SLAC; Huang, C.; /UCLA; Ischebeck, R.; Iverson, R.H.; /SLAC; Joshi, C.; /UCLA; Katsouleas, T.; /Southern California U.; Kirby, N.; /SLAC; Lu, W.; Marsh, K.A.; Mori, W.B.; /UCLA; Muggli, P.; Oz, E.; /Southern California U.; Siemann, R.H.; Walz, D.R.; /SLAC; Zhou, M.; /UCLA

    2012-06-12T23:59:59.000Z

    The scaling of the two important figures of merit, the transformer ratio T and the longitudinal electric field E{sub z}, with the peak drive-bunch current I{sub p}, in a nonlinear plasma wakefield accelerator is presented for the first time. The longitudinal field scales as I{sub P}{sup 0.623{+-}0.007}, in good agreement with nonlinear wakefield theory ({approx}I{sub P}{sup 0.5}), while the unloaded transformer ratio is shown to be greater than unity and scales weakly with the bunch current. The effect of bunch head erosion on both parameters is also discussed.

  10. Numerical Verification of the Power Transfer and Wakefield Coupling in the CLIC Two-Beam Accelerator

    E-Print Network [OSTI]

    Candel, Arno; NG, C; Rawat, V; Schussman, G; Ko, K; Syratchev, I; Grudiev, A; Wuensch, W

    2011-01-01T23:59:59.000Z

    The Compact Linear Collider (CLIC) provides a path to a multi-TeV accelerator to explore the energy frontier of High Energy Physics. Its two-beam accelerator (TBA) concept envisions complex 3D structures, which must be modeled to high accuracy so that simulation results can be directly used to prepare CAD drawings for machining. The required simulations include not only the fundamental mode properties of the accelerating structures but also the Power Extraction and Transfer Structure (PETS), as well as the coupling between the two systems. Time-domain simulations will be performed to understand pulse formation, wakefield damping, fundamental power transfer and wakefield coupling in these structures. Applying SLAC’s parallel finite element code suite, these large-scale problems will be solved on some of the largest supercomputers available. The results will help to identify potential issues and provide new insights on the design, leading to further improvements on the novel two-beam accelerator scheme.

  11. Wakefield acceleration in atmospheric plasmas: a possible source of MeV electrons

    E-Print Network [OSTI]

    Arrayás, M; Seviour, R; Trueba, J L

    2015-01-01T23:59:59.000Z

    Intense electromagnetic pulses interacting with a plasma can create a wake of plasma oscillations. Electrons trapped in such oscillations can be accelerated under certain conditions to very high energies. We study the conditions for the wakefield acceleration to produce MeV electrons in atmospheric plasmas. This mechanism may explain the origin of MeV or runaway electrons needed in the current theories for the production of Terrestrial Gamma ray Flashes.

  12. Start-to-end beam dynamics simulation of double triangular current profile generation in Argonne Wakefield Accelerator

    SciTech Connect (OSTI)

    Ha, G.; Power, J.; Kim, S. H.; Gai, W.; Kim, K.-J.; Cho, M. H.; Namkung, W. [POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of); Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of) and Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); POSTECH, Pohang, Gyeongbuk, 790-784 (Korea, Republic of) and Pohang Accelerator Laboratory, Pohang, Gyeongbuk, 790-784 (Korea, Republic of); Pohang Accelerator Laboratory, Pohang, Gyeongbuk, 790-784 (Korea, Republic of)

    2012-12-21T23:59:59.000Z

    Double triangular current profile (DT) gives a high transformer ratio which is the determining factor of the performance of collinear wakefield accelerator. This current profile can be generated using the emittance exchange (EEX) beam line. Argonne Wakefield Accelerator (AWA) facility plans to generate DT using the EEX beam line. We conducted start-to-end simulation for the AWA beam line using PARMELA code. Also, we discuss requirements of beam parameters for the generation of DT.

  13. Laser pulse propagation in inhomogeneous magnetoplasma channels and wakefield acceleration

    SciTech Connect (OSTI)

    Sharma, B. S., E-mail: bs-phy@yahoo.com; Jain, Archana [Government College Kota, Kota 324001 (India)] [Government College Kota, Kota 324001 (India); Jaiman, N. K. [Department of Pure and Applied Physics, University of Kota, Kota 324010 (India)] [Department of Pure and Applied Physics, University of Kota, Kota 324010 (India); Gupta, D. N. [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)] [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Jang, D. G.; Suk, H. [Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)] [Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of); Kulagin, V. V. [Sternberg Astronomical Institute of Moscow State University, Moscow 119992 (Russian Federation)] [Sternberg Astronomical Institute of Moscow State University, Moscow 119992 (Russian Federation)

    2014-02-15T23:59:59.000Z

    Wakefield excitation in a preformed inhomogeneous parabolic plasma channel by an intense relativistic (?10{sup 19}?W/cm{sup 2}) circularly polarized Gaussian laser pulse is investigated analytically and numerically in the presence of an external longitudinal magnetic field. A three dimensional envelope equation for the evolution of the laser pulse is derived, which includes the effect of the nonparaxial and applied external magnetic field. A relation for the channel radius with the laser spot size is derived and examines numerically to see the external magnetic field effect. It is observed that the channel radius depends on the applied external magnetic field. An analytical expression for the wakefield is derived and validated with the help of a two dimensional particle in cell (2D PIC) simulation code. It is shown that the electromagnetic nature of the wakes in an inhomogeneous plasma channel makes their excitation nonlocal, which results in change of fields with time and external magnetic field due to phase mixing of the plasma oscillations with spatially varying frequencies. The magnetic field effect on perturbation of the plasma density and decreasing length is also analyzed numerically. In addition, it has been shown that the electron energy gain in the inhomogeneous parabolic magnetoplasma channel can be increased significantly compared with the homogeneous plasma channel.

  14. Injection and acceleration of electron bunch in a plasma wakefield produced by a chirped laser pulse

    SciTech Connect (OSTI)

    Afhami, Saeedeh; Eslami, Esmaeil, E-mail: eeslami@iust.ac.ir [Department of Physics, Iran University of Science and Technology (IUST), Narmak, Tehran 16846-13114 (Iran, Islamic Republic of)

    2014-06-15T23:59:59.000Z

    An ultrashort laser pulse propagating in plasma can excite a nonlinear plasma wakefield which can trap and accelerate charged particles up to GeV. One-dimensional analysis of electron injection, trapping, and acceleration by different chirped pulses propagating in plasma is investigated numerically. In this paper, we inject electron bunches in front of the chirped pulses. It is indicated that periodical chirped laser pulse can trap electrons earlier than other pulses. It is shown that periodical chirped laser pulses lead to decrease the minimum momentum necessary to trap the electrons. This is due to the fact that periodical chirped laser pulses are globally much efficient than nonchirped pulses in the wakefield generation. It is found that chirped laser pulses could lead to much larger electron energy than that of nonchirped pulses. Relative energy spread has a lower value in the case of periodical chirped laser pulses.

  15. Emittance and Current of Electrons Trapped in a Plasma Wakefield Accelerator

    SciTech Connect (OSTI)

    Kirby, N; Blumenfeld, I; Clayton, C.E.; Decker, F.J.; Hogan, M.J.; Huang, C.; Ischebeck, R.; Iverson, R.H.; Joshi, C.; Katsouleas, T.; Lu, W.; Marsh, K.A.; Mori, W.B.; Muggli, P; Oz, E.; Siemann, R.H.; Walz, D.R.; Zhou, M.; /SLAC /UCLA /USC

    2008-09-24T23:59:59.000Z

    In recent experiments plasma electrons became trapped in a plasma wakefield accelerator (PWFA). The transverse size of these trapped electrons on a downstream diagnostic yields an upper limit measurement of transverse normalized emittance divided by peak current, {var_epsilon}{sub N,x}/I. The lowest upper limit for {var_epsilon}{sub N,x}/I measured in the experiment is 1.3 {center_dot} 10{sup -10} m/A.

  16. Proton-driven plasma wakefield acceleration: a path to the future of high-energy particle physics

    E-Print Network [OSTI]

    Assmann, R; Bohl, T; Bracco, C; Buttenschon, B; Butterworth, A; Caldwell, A; Chattopadhyay, S; Cipiccia, S; Feldbaumer, E; Fonseca, R A; Goddard, B; Gross, M; Grulke, O; Gschwendtner, E; Holloway, J; Huang, C; Jaroszynski, D; Jolly, S; Kempkes, P; Lopes, N; Lotov, K; Machacek, J; Mandry, S R; McKenzie, J W; Meddahi, M; Militsyn, B L; Moschuering, N; Muggli, P; Najmudin, Z; Noakes, T C Q; Norreys, P A; Oz, E; Pardons, A; Petrenko, A; Pukhov, A; Rieger, K; Reimann, O; Ruhl, H; Shaposhnikova, E; Silva, L O; Sosedkin, A; Tarkeshian, R; Trines, R M G N; Tuckmantel, T; Vieira, J; Vincke, H; Wing, M; Xia, G

    2014-01-01T23:59:59.000Z

    New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach is to exploit the properties of plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or an electron bunch into the plasma. However, the maximum energy gain of electrons accelerated in a single plasma stage is limited by the energy of the driver. Proton bunches are the most promising drivers of wakefields to accelerate electrons to the TeV energy scale in a single stage. An experimental program at CERN -- the AWAKE experiment -- has been launched to study in detail the important physical processes and to demonstrate the power of proton-driven plasma wakefield acceleration. Here we review the physical principles and some experimental considerations for a future proton-driven plasma wakefield accelerator.

  17. Proton-driven plasma wakefield acceleration: a path to the future of high-energy particle physics

    E-Print Network [OSTI]

    Assmann, R; Bohl, T; Bracco, C; Buttenschon, B; Butterworth, A; Caldwell, A; Chattopadhyay, S; Cipiccia, S; Feldbaumer, E; Fonseca, R A; Goddard, B; Gross, M; Grulke, O; Gschwendtner, E; Holloway, J; Huang, C; Jaroszynski, D; Jolly, S; Kempkes, P; Lopes, N; Lotov, K; Machacek, J; Mandry, S R; McKenzie, J W; Meddahi, M; Militsyn, B L; Moschuering, N; Muggli, P; Najmudin, Z; Noakes, T C Q; Norreys, P A; Oz, E; Pardons, A; Petrenko, A; Pukhov, A; Rieger, K; Reimann, O; Ruhl, H; Shaposhnikova, E; Silva, L O; Sosedkin, A; Tarkeshian, R; Trines, R M G N; Tuckmantel, T; Vieira, J; Vincke, H; Wing, M; Xia G , G

    2014-01-01T23:59:59.000Z

    New acceleration technology is mandatory for the future elucidation of fundamental particles and their interactions. A promising approach is to exploit the properties of plasmas. Past research has focused on creating large-amplitude plasma waves by injecting an intense laser pulse or an electron bunch into the plasma. However, the maximum energy gain of electrons accelerated in a single plasma stage is limited by the energy of the driver. Proton bunches are the most promising drivers of wakefields to accelerate electrons to the TeV energy scale in a single stage. An experimental program at CERN { the AWAKE experiment { has been launched to study in detail the important physical processes and to demonstrate the power of proton-driven plasma wakefield acceleration. Here we review the physical principles and some experimental considerations for a future proton-driven plasma wakefield accelerator.

  18. Energy Doubling of 42 GeV Electrons in a Meter-scale Plasma Wakefield Accelerator

    SciTech Connect (OSTI)

    Blumenfeld, Ian; Clayton, Christopher E.; Decker, Franz-Josef; Hogan, Mark J.; Huang, Chengkun; Ischebeck, Rasmus; Iverson, Richard; Joshi, Chandrashekhar; Katsouleas,; Kirby, Neil; Lu, Wei; Marsh, Kenneth A.; Mori, Warren B.; Muggli, Patric; Oz, Erdem; Siemann, Robert H.; Walz, Dieter; Zhou, Miaomiao; /SLAC /UCLA /Southern California U.

    2007-03-14T23:59:59.000Z

    The energy frontier of particle physics is several trillion electron volts, but colliders capable of reaching this regime (such as the Large Hadron Collider and the International Linear Collider) are costly and time-consuming to build; it is therefore important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators, a drive beam (either laser or particle) produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultrahigh accelerating fields over a substantial length to achieve a significant energy gain. Here we show that an energy gain of more than 42 GeV is achieved in a plasma wakefield accelerator of 85 cm length, driven by a 42 GeV electron beam at the Stanford Linear Accelerator Center (SLAC). The results are in excellent agreement with the predictions of three-dimensional particle-in-cell simulations. Most of the beam electrons lose energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of {approx} 52GV m{sup -1}. This effectively doubles their energy, producing the energy gain of the 3-km-long SLAC accelerator in less than a meter for a small fraction of the electrons in the injected bunch. This is an important step towards demonstrating the viability of plasma accelerators for high-energy physics applications.

  19. Sub-femtosecond electron bunches created by direct laser acceleration in a laser wakefield accelerator with ionization injection

    E-Print Network [OSTI]

    Lemos, N; Marsh, K A; Joshi, C

    2015-01-01T23:59:59.000Z

    In this work, we will show through three-dimensional particle-in-cell simulations that direct laser acceleration in laser a wakefield accelerator can generate sub-femtosecond electron bunches. Two simulations were done with two laser pulse durations, such that the shortest laser pulse occupies only a fraction of the first bubble, whereas the longer pulse fills the entire first bubble. In the latter case, as the trapped electrons moved forward and interacted with the high intensity region of the laser pulse, micro-bunching occurred naturally, producing 0.5 fs electron bunches. This is not observed in the short pulse simulation.

  20. Detailed dynamics of electron beams self-trapped and accelerated in a self-modulated laser wakefield

    E-Print Network [OSTI]

    Umstadter, Donald

    . These features are explained by analysis and test particle simulations of electron dynamics during acceleration wave,1 such as the plasma wakefield accel- erator, the plasma beat-wave accelerator, the Laser Wake the linear dephasing limit, and explained it, using Particle-In-Cell PIC simulations, as a result

  1. Laser-PlasmaWakefield Acceleration with Higher Order Laser Modes

    E-Print Network [OSTI]

    Geddes, C.G.R.

    2011-01-01T23:59:59.000Z

    Design considerations for a laser-plasma linear collider,"E.Esarey, and W.P.Leemans, "Free-electron laser driven bythe LBNL laser-plasma accelerator," in Proc. Adv. Acc. Con.

  2. Correlation of Beam Parameters to Decelerating Gradient in the E-167 Plasma Wakefield Acceleration Experiment

    SciTech Connect (OSTI)

    Blumenfeld, I.; Berry, M.; Decker, F.-J.; Hogan, M.J.; Ischebeck, R.; Iverson, R.; Kirby, N.; Siemann, R.; Walz, D.; /SLAC; Clayton, C.E.; Huang, C.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.B.; Zhou, M.; /UCLA; Katsouleas, T.C.; Muggli, P.; Oz, E.; /Southern California U.

    2007-06-27T23:59:59.000Z

    Recent experiments at SLAC have shown that high gradient acceleration of electrons is achievable in meter scale plasmas [1,2]. Results from these experiments show that the wakefield is sensitive to parameters in the electron beam which drives it. In the experiment the bunch length and beam waist location were varied systematically at constant charge. Here we investigate the correlation of peak beam current to the decelerating gradient. Limits on the transformer ratio will also be discussed. The results are compared to simulation.

  3. Multi-bunch Plasma Wakefield Acceleration at ATF

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    10 P D 9.7972e+18 3-D 0.002032 E Ewb 0.02052 Kp 590 r 15 Wake build-up at resonance: 3% detuning accelerates later bunches 0 0.5 1 1.5 -0.03 -0.02 -0.01...

  4. Application of High-performance Visual Analysis Methods to Laser Wakefield Particle Acceleration Data

    SciTech Connect (OSTI)

    Rubel, Oliver; Prabhat, Mr.; Wu, Kesheng; Childs, Hank; Meredith, Jeremy; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Ahern, Sean; Weber, Gunther H.; Messmer, Peter; Hagen, Hans; Hamann, Bernd; Bethel, E. Wes

    2008-08-28T23:59:59.000Z

    Our work combines and extends techniques from high-performance scientific data management and visualization to enable scientific researchers to gain insight from extremely large, complex, time-varying laser wakefield particle accelerator simulation data. We extend histogram-based parallel coordinates for use in visual information display as well as an interface for guiding and performing data mining operations, which are based upon multi-dimensional and temporal thresholding and data subsetting operations. To achieve very high performance on parallel computing platforms, we leverage FastBit, a state-of-the-art index/query technology, to accelerate data mining and multi-dimensional histogram computation. We show how these techniques are used in practice by scientific researchers to identify, visualize and analyze a particle beam in a large, time-varying dataset.

  5. Enhanced dielectric-wall linear accelerator

    DOE Patents [OSTI]

    Sampayan, S.E.; Caporaso, G.J.; Kirbie, H.C.

    1998-09-22T23:59:59.000Z

    A dielectric-wall linear accelerator is enhanced by a high-voltage, fast e-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface. 6 figs.

  6. Optimization of Drive-Bunch Current Profile for Enhanced Transformer Ratio in Beam-Driven Acceleration Techniques

    SciTech Connect (OSTI)

    Lemery, F.; Mihalcea, D.; Prokop, C.R.; /Northern Illinois U.; Piot, P.; /Northern Illinois U. /Fermilab

    2012-07-08T23:59:59.000Z

    In recent years, wakefield acceleration has gained attention due to its high acceleration gradients and cost effectiveness. In beam-driven wakefield acceleration, a critical parameter to optimize is the transformer ratio. It has been shown that current shaping of electron beams allows for enhanced (> 2) transformer ratios. In this paper we present the optimization of the pulse shape of the drive bunch for dielectric-wakefield acceleration.

  7. ACE3P Computations of Wakefield Coupling in the CLIC Two-Beam Accelerator

    SciTech Connect (OSTI)

    Candel, Arno; Li, Z.; Ng, C.; Rawat, V.; Schussman, G.; Ko, K.; /SLAC; Syratchev, I.; Grudiev, A.; Wuensch, W.; /CERN

    2010-10-27T23:59:59.000Z

    The Compact Linear Collider (CLIC) provides a path to a multi-TeV accelerator to explore the energy frontier of High Energy Physics. Its novel two-beam accelerator concept envisions rf power transfer to the accelerating structures from a separate high-current decelerator beam line consisting of power extraction and transfer structures (PETS). It is critical to numerically verify the fundamental and higher-order mode properties in and between the two beam lines with high accuracy and confidence. To solve these large-scale problems, SLAC's parallel finite element electromagnetic code suite ACE3P is employed. Using curvilinear conformal meshes and higher-order finite element vector basis functions, unprecedented accuracy and computational efficiency are achieved, enabling high-fidelity modeling of complex detuned structures such as the CLIC TD24 accelerating structure. In this paper, time-domain simulations of wakefield coupling effects in the combined system of PETS and the TD24 structures are presented. The results will help to identify potential issues and provide new insights on the design, leading to further improvements on the novel CLIC two-beam accelerator scheme.

  8. An ultrashort pulse ultra-violet radiation undulator source driven by a laser plasma wakefield accelerator

    SciTech Connect (OSTI)

    Anania, M. P. [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); INFN, Laboratori Nazionali di Frascati, I-00044 Frascati (Italy); Brunetti, E.; Wiggins, S. M.; Grant, D. W.; Welsh, G. H.; Issac, R. C.; Cipiccia, S.; Shanks, R. P.; Manahan, G. G.; Aniculaesei, C.; Jaroszynski, D. A., E-mail: d.a.jaroszynski@strath.ac.uk [SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Geer, S. B. van der; Loos, M. J. de [Pulsar Physics, Burghstraat 47, 5614 BC Eindhoven (Netherlands); Poole, M. W.; Shepherd, B. J. A.; Clarke, J. A. [ASTeC, STFC, Daresbury Laboratory, Warrington WA4 4AD (United Kingdom); Gillespie, W. A. [SUPA, School of Engineering, Physics and Mathematics, University of Dundee, Dundee DD1 4HN (United Kingdom); MacLeod, A. M. [School of Computing and Creative Technologies, University of Abertay Dundee, Dundee DD1 1HG (United Kingdom)

    2014-06-30T23:59:59.000Z

    Narrow band undulator radiation tuneable over the wavelength range of 150–260?nm has been produced by short electron bunches from a 2?mm long laser plasma wakefield accelerator based on a 20?TW femtosecond laser system. The number of photons measured is up to 9?×?10{sup 6} per shot for a 100 period undulator, with a mean peak brilliance of 1?×?10{sup 18} photons/s/mrad{sup 2}/mm{sup 2}/0.1% bandwidth. Simulations estimate that the driving electron bunch r.m.s. duration is as short as 3 fs when the electron beam has energy of 120–130?MeV with the radiation pulse duration in the range of 50–100 fs.

  9. Measurements of the critical power for self-injection of electrons in a laser wakefield accelerator

    SciTech Connect (OSTI)

    Froula, D H; Clayton, C E; Doppner, T; Fonseca, R A; Marsh, K A; Barty, C J; Divol, L; Glenzer, S H; Joshi, C; Lu, W; Martins, S F; Michel, P; Mori, W; Palastro, J P; Pollock, B B; Pak, A; Ralph, J E; Ross, J S; Siders, C; Silva, L O; Wang, T

    2009-06-02T23:59:59.000Z

    A laser wakefield acceleration study has been performed in the matched, self-guided, blow-out regime where a 10 J, 60 fs laser produced 720 {+-} 50 MeV quasi-monoenergetic electrons with a divergence of {Delta}{theta} = 2.85 {+-} 0.15 mRad. While maintaining a nearly constant plasma density (3 x 10{sup 18} cm{sup -3}), a linear electron energy gain was measured from 100 MeV to 700 MeV when the plasma length was scaled from 3 mm to 8 mm. Absolute charge measurements indicate that self-injection occurs when P/P{sub cr} > 4 and saturates around 100 pC for P/P{sub cr} > 12. The results are compared with both analytical scalings and full 3D particle-in-cell simulations.

  10. Quasimonoenergetic collimated electron beams from a laser wakefield acceleration in low density pure nitrogen

    SciTech Connect (OSTI)

    Tao, Mengze [Key Laboratory for Laser Plasmas (MOE) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Bejing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Hafz, Nasr A. M., E-mail: nasr@sjtu.edu.cn; Li, Song; Mirzaie, Mohammad; Elsied, Ahmed M. M.; Ge, Xulei; Liu, Feng; Sokollik, Thomas; Sheng, Zhengming; Zhang, Jie, E-mail: jzhang1@sjtu.edu.cn [Key Laboratory for Laser Plasmas (MOE) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Chen, Liming [Bejing National Laboratory of Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China)

    2014-07-15T23:59:59.000Z

    A laser wakefield acceleration (LWFA) experiment is performed using 30 TW, 30 fs, and 800?nm laser pulses, focused onto pure nitrogen plasma having relatively low densities in the range of 0.8×10{sup 18}?cm{sup ?3} to 2.7×10{sup 18}?cm{sup ?3}. Electron beams having a low divergence of ?3??mrad (full-width at half-maximum) and quasi-monoenergetic peak energies of ?105??MeV are achieved over 4-mm interaction length. The total electron beam charge reached to 2 nC, however, only 1%–2% of this (tens of pC) had energies >35?MeV. We tried different conditions to optimize the electron beam acceleration; our experiment verifies that lower nitrogen plasma densities are generating electron beams with high quality in terms of divergence, charge, pointing stability, and maximum energy. In addition, if LWFA is to be widely used as a basis for compact particle accelerators in the future, therefore, from the economic and safety points of view we propose the use of nitrogen gas rather than helium or hydrogen.

  11. Wakefield and RF Kicks Due to Coupler Asymmetry in TESLA-Type Accelerating Cavities

    SciTech Connect (OSTI)

    Bane, K.L.F.; Adolphsen, C.; Li, Z.; /SLAC; Dohlus, M.; Zagorodnov, I.; /DESY; Gonin, I.; Lunin, A.; Solyak, N.; Yakovlev, V.; /Fermilab; Gjonaj, E.; Weiland, T.; /Darmstadt, Tech. Hochsch.

    2008-07-07T23:59:59.000Z

    In a future linear collider, such as the International Linear Collider (ILC), trains of high current, low emittance bunches will be accelerated in a linac before colliding at the interaction point. Asymmetries in the accelerating cavities of the linac will generate fields that will kick the beam transversely and degrade the beam emittance and thus the collider performance. In the main linac of the ILC, which is filled with TESLA-type superconducting cavities, it is the fundamental (FM) and higher mode (HM) couplers that are asymmetric and thus the source of such kicks. The kicks are of two types: one, due to (the asymmetry in) the fundamental RF fields and the other, due to transverse wakefields that are generated by the beam even when it is on axis. In this report we calculate the strength of these kicks and estimate their effect on the ILC beam. The TESLA cavity comprises nine cells, one HM coupler in the upstream end, and one (identical, though rotated) HM coupler and one FM coupler in the downstream end (for their shapes and location see Figs. 1, 2) [1]. The cavity is 1.1 m long, the iris radius 35 mm, and the coupler beam pipe radius 39 mm. Note that the couplers reach closer to the axis than the irises, down to a distance of 30 mm.

  12. Vacuum Insulator Development for the Dielectric Wall Accelerator

    SciTech Connect (OSTI)

    Harris, J R; Blackfield, D; Caporaso, G J; Chen, Y; Hawkins, S; Kendig, M; Poole, B; Sanders, D M; Krogh, M; Managan, J E

    2008-03-17T23:59:59.000Z

    At Lawrence Livermore National Laboratory, we are developing a new type of accelerator, known as a Dielectric Wall Accelerator, in which compact pulse forming lines directly apply an accelerating field to the beam through an insulating vacuum boundary. The electrical strength of this insulator may define the maximum gradient achievable in these machines. To increase the system gradient, we are using 'High Gradient Insulators' composed of alternating layers of dielectric and metal for the vacuum insulator. In this paper, we present our recent results from experiment and simulation, including the first test of a High Gradient Insulator in a functioning Dielectric Wall Accelerator cell.

  13. Modeling Self-Ionized Plasma Wakefield Acceleration for Afterburner Parameters Using QuickPIC

    SciTech Connect (OSTI)

    Zhou, M.; Clayton, C.E.; Decyk, V.K.; Huang, C.; Johnson, D.K.; Joshi, C.; Lu, W.; Mori, W.B.; Tsung, F.S.; /UCLA; Deng, S.; Katsouleas, T.; Muggli, P.; Oz, E.; /Southern; Decker, F.-J.; Iverson, R.; O'Connel, C.; Walz, D.; /SLAC

    2006-01-25T23:59:59.000Z

    For the parameters envisaged in possible afterburner stages[1] of a plasma wakefield accelerator (PWFA), the self-fields of the particle beam can be intense enough to tunnel ionize some neutral gases. Tunnel ionization has been investigated as a way for the beam itself to create the plasma, and the wakes generated may differ from those generated in pre-ionized plasmas[2],[3]. However, it is not practical to model the whole stage of PWFA with afterburner parameters using the models described in [2] and [3]. Here we describe the addition of a tunnel ionization package using the ADK model into QuickPIC, a highly efficient quasi-static particle in cell (PIC) code which can model a PWFA with afterburner parameters. Comparison between results from OSIRIS (a full PIC code with ionization) and from QuickPIC with the ionization package shows good agreement. Preliminary results using parameters relevant to the E164X experiment and the upcoming E167 experiment at SLAC are shown.

  14. VOLUME 82, NUMBER 6 P H Y S I C A L R E V I E W L E T T E R S 8 FEBRUARY 1999 Multimode Analysis of the Hollow Plasma Channel Wakefield Accelerator

    E-Print Network [OSTI]

    Wurtele, Jonathan

    ]. In conventional accelerators, the size of these accel- erating fields is limited by breakdown. For two decades wakefield accelerator, the plasma wave is excited by the self-fields of an intense relativistic particle- neous plasma. These properties make it well suited as a structure for both particle beam wakefield

  15. HIGH-GRADIENT, HIGH-TRANSFORMER-RATIO, DIELECTRIC WAKE FIELD ACCELERATOR

    SciTech Connect (OSTI)

    Jay L. Hirshfield

    2012-04-12T23:59:59.000Z

    The Phase I work reported here responds to DoE'ss stated need "...to develop improved accelerator designs that can provide very high gradient (>200 MV/m for electrons...) acceleration of intense bunches of particles." Omega-P'�s approach to this goal is through use of a ramped train of annular electron bunches to drive a coaxial dielectric wakefield accelerator (CDWA) structure. This approach is a direct extension of the CDWA concept from acceleration in wake fields caused by a single drive bunch, to the more efficient acceleration that we predict can be realized from a tailored (or ramped) train of several drive bunches. This is possible because of a much higher transformer ratio for the latter. The CDWA structure itself has a number of unique features, including: a high accelerating gradient G, potentially with G > 1 GeV/m; continuous energy coupling from drive to test bunches without transfer structures; inherent transverse focusing forces for particles in the accelerated bunch; highly stable motion of high charge annular drive bunches; acceptable alignment tolerances for a multi-section system. What is new in the present approach is that the coaxial dielectric structure is now to be energized by-not one-�but by a short train of ramped annular-shaped drive bunches moving in the outer coaxial channel of the structure. We have shown that this allows acceleration of an electron bunch traveling along the axis in the inner channel with a markedly higher transformer ratio T than for a single drive bunch. As described in this report, the structure will be a GHz-scale prototype with cm-scale transverse dimensions that is expected to confirm principles that can be applied to the design of a future THz-scale high gradient (> 500 MV/m) accelerator with mm-scale transverse dimensions. We show here a new means to significantly increase the transformer ratio T of the device, and thereby to significantly improve its suitability as a flexible and effective component in a future high energy, high gradient accelerator facility. We predict that the T of a high gradient CDWA can be increased by a substantial factor; this enhancement is dramatically greater than what has been demonstrated heretofore. This large enhancement in T that we predict arises from using a train of three or four drive bunches in which the spacing of the bunches and their respective charges are selected according to a simple principle that requires each bunch lose energy to the wakefields at the same rate, so as not to sacrifice drive beam efficiency�¢����as would be the case if one bunch exhausted its available energy while others had not. It is anticipated that results from the study proposed here can have a direct impact on design of the dielectric accelerator in a TeV-scale collider concept, and in the accelerator for an x-ray FEL.

  16. Electron diffraction using ultrafast electron bunches from a laser-wakefield accelerator at kHz repetition rate

    SciTech Connect (OSTI)

    He, Z.-H.; Thomas, A. G. R.; Nees, J. A.; Hou, B.; Krushelnick, K. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48106-2099 (United States)] [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48106-2099 (United States); Beaurepaire, B.; Malka, V.; Faure, J. [Laboratoire d'Optique Appliquee, ENSTA-CNRS-Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France)] [Laboratoire d'Optique Appliquee, ENSTA-CNRS-Ecole Polytechnique, UMR 7639, 91761 Palaiseau (France)

    2013-02-11T23:59:59.000Z

    We show that electron bunches in the 50-100 keV range can be produced from a laser wakefield accelerator using 10 mJ, 35 fs laser pulses operating at 0.5 kHz. It is shown that using a solenoid magnetic lens, the electron bunch distribution can be shaped. The resulting transverse and longitudinal coherence is suitable for producing diffraction images from a polycrystalline 10 nm aluminum foil. The high repetition rate, the stability of the electron source, and the fact that its uncorrelated bunch duration is below 100 fs make this approach promising for the development of sub-100 fs ultrafast electron diffraction experiments.

  17. Laser Wakefield Acceleration: Structural and Dynamic Studies. Final Technical Report ER40954

    SciTech Connect (OSTI)

    Downer, Michael C.

    2014-12-19T23:59:59.000Z

    Particle accelerators enable scientists to study the fundamental structure of the universe, but have become the largest and most expensive of scientific instruments. In this project, we advanced the science and technology of laser-plasma accelerators, which are thousands of times smaller and less expensive than their conventional counterparts. In a laser-plasma accelerator, a powerful laser pulse exerts light pressure on an ionized gas, or plasma, thereby driving an electron density wave, which resembles the wake behind a boat. Electrostatic fields within this plasma wake reach tens of billions of volts per meter, fields far stronger than ordinary non-plasma matter (such as the matter that a conventional accelerator is made of) can withstand. Under the right conditions, stray electrons from the surrounding plasma become trapped within these “wake-fields”, surf them, and acquire energy much faster than is possible in a conventional accelerator. Laser-plasma accelerators thus might herald a new generation of compact, low-cost accelerators for future particle physics, x-ray and medical research. In this project, we made two major advances in the science of laser-plasma accelerators. The first of these was to accelerate electrons beyond 1 gigaelectronvolt (1 GeV) for the first time. In experimental results reported in Nature Communications in 2013, about 1 billion electrons were captured from a tenuous plasma (about 1/100 of atmosphere density) and accelerated to 2 GeV within about one inch, while maintaining less than 5% energy spread, and spreading out less than ½ milliradian (i.e. ½ millimeter per meter of travel). Low energy spread and high beam collimation are important for applications of accelerators as coherent x-ray sources or particle colliders. This advance was made possible by exploiting unique properties of the Texas Petawatt Laser, a powerful laser at the University of Texas at Austin that produces pulses of 150 femtoseconds (1 femtosecond is 10-15 seconds) in duration and 150 Joules in energy (equivalent to the muzzle energy of a small pistol bullet). This duration was well matched to the natural electron density oscillation period of plasma of 1/100 atmospheric density, enabling efficient excitation of a plasma wake, while this energy was sufficient to drive a high-amplitude wake of the right shape to produce an energetic, collimated electron beam. Continuing research is aimed at increasing electron energy even further, increasing the number of electrons captured and accelerated, and developing applications of the compact, multi-GeV accelerator as a coherent, hard x-ray source for materials science, biomedical imaging and homeland security applications. The second major advance under this project was to develop new methods of visualizing the laser-driven plasma wake structures that underlie laser-plasma accelerators. Visualizing these structures is essential to understanding, optimizing and scaling laser-plasma accelerators. Yet prior to work under this project, computer simulations based on estimated initial conditions were the sole source of detailed knowledge of the complex, evolving internal structure of laser-driven plasma wakes. In this project we developed and demonstrated a suite of optical visualization methods based on well-known methods such as holography, streak cameras, and coherence tomography, but adapted to the ultrafast, light-speed, microscopic world of laser-driven plasma wakes. Our methods output images of laser-driven plasma structures in a single laser shot. We first reported snapshots of low-amplitude laser wakes in Nature Physics in 2006. We subsequently reported images of high-amplitude laser-driven plasma “bubbles”, which are important for producing electron beams with low energy spread, in Physical Review Letters in 2010. More recently, we have figured out how to image laser-driven structures that change shape while propagating in a single laser shot. The latter techniques, which use the methods of computerized tomography, were demonstrated on test objects – e.g. laser-d

  18. Improvements to laser wakefield accelerated electron beam stability, divergence, and energy spread using three-dimensional printed two-stage gas cell targets

    SciTech Connect (OSTI)

    Vargas, M.; Schumaker, W.; He, Z.-H.; Zhao, Z.; Behm, K.; Chvykov, V.; Hou, B.; Krushelnick, K.; Maksimchuk, A.; Yanovsky, V.; Thomas, A. G. R., E-mail: agrt@umich.edu [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2014-04-28T23:59:59.000Z

    High intensity, short pulse lasers can be used to accelerate electrons to ultra-relativistic energies via laser wakefield acceleration (LWFA) [T. Tajima and J. M. Dawson, Phys. Rev. Lett. 43, 267 (1979)]. Recently, it was shown that separating the injection and acceleration processes into two distinct stages could prove beneficial in obtaining stable, high energy electron beams [Gonsalves et al., Nat. Phys. 7, 862 (2011); Liu et al., Phys. Rev. Lett. 107, 035001 (2011); Pollock et al., Phys. Rev. Lett. 107, 045001 (2011)]. Here, we use a stereolithography based 3D printer to produce two-stage gas targets for LWFA experiments on the HERCULES laser system at the University of Michigan. We demonstrate substantial improvements to the divergence, pointing stability, and energy spread of a laser wakefield accelerated electron beam compared with a single-stage gas cell or gas jet target.

  19. Plasma wakefields driven by an incoherent combination of laser pulses: a path towards high-average power laser-plasma accelerators

    SciTech Connect (OSTI)

    Benedetti, C.; Schroeder, C.B.; Esarey, E.; Leemans, W.P.

    2014-05-01T23:59:59.000Z

    he wakefield generated in a plasma by incoherently combining a large number of low energy laser pulses (i.e.,without constraining the pulse phases) is studied analytically and by means of fully-self-consistent particle-in-cell simulations. The structure of the wakefield has been characterized and its amplitude compared with the amplitude of the wake generated by a single (coherent) laser pulse. We show that, in spite of the incoherent nature of the wakefield within the volume occupied by the laser pulses, behind this region the structure of the wakefield can be regular with an amplitude comparable or equal to that obtained from a single pulse with the same energy. Wake generation requires that the incoherent structure in the laser energy density produced by the combined pulses exists on a time scale short compared to the plasma period. Incoherent combination of multiple laser pulses may enable a technologically simpler path to high-repetition rate, high-average power laser-plasma accelerators and associated applications.

  20. Dielectric-Lined High-Gradient Accelerator Structure

    SciTech Connect (OSTI)

    Jay L. Hirshfield

    2012-04-24T23:59:59.000Z

    Rectangular particle accelerator structures with internal planar dielectric elements have been studied, with a view towards devising structures with lower surface fields for a given accelerating field, as compared with structures without dielectrics. Success with this concept is expected to allow operation at higher accelerating gradients than otherwise on account of reduced breakdown probabilities. The project involves studies of RF breakdown on amorphous dielectrics in test cavities that could enable high-gradient structures to be built for a future multi-TeV collider. The aim is to determine what the limits are for RF fields at the surfaces of selected dielectrics, and the resulting acceleration gradient that could be achieved in a working structure. The dielectric of principal interest in this study is artificial CVD diamond, on account of its advertised high breakdown field ({approx}2 GV/m for dc), low loss tangent, and high thermal conductivity. Experimental studies at mm-wavelengths on materials and structures for achieving high acceleration gradient were based on the availability of the 34.3 GHz third-harmonic magnicon amplifier developed by Omega-P, and installed at the Yale University Beam Physics Laboratory. Peak power from the magnicon was measured to be about 20 MW in 0.5 {micro}s pulses, with a gain of 54 dB. Experiments for studying RF high-field effects on CVD diamond samples failed to show any evidence after more than 10{sup 5} RF pulses of RF breakdown up to a tangential surface field strength of 153 MV/m; studies at higher fields were not possible due to a degradation in magnicon performance. A rebuild of the tube is underway at this writing. Computed performance for a dielectric-loaded rectangular accelerator structure (DLA) shows highly competitive properties, as compared with an existing all-metal structure. For example, comparisons were made of a DLA structure having two planar CVD diamond elements with a all-metal CERN structure HDS operating at 30 GHz. It was shown that the ratio of maximum surface electric field to accelerating field at the metal wall is only 0.35-0.4 for DLA, much smaller than the value 2.2 for HDS; and the ratio of surface magnetic field to accelerating field is 3.0 mA/V for DLA, compared with 3.45 mA/V for HDS. These values bode well for DLA in helping to avoid breakdown and to reducing pulsed surface heating and fatigue. The shunt impedance is found to be 160-175 M{Omega}/m for DLA, as compared to 99 M{Omega}/m for HDS. Conclusions are reached from this project that CVD diamond appears promising as a dielectric with a high threshold for RF breakdown, and that rectangular accelerator structures can be devised using planar CVD diamond elements that could be operated at higher acceleration gradients with low probability of RF breakdown, as compared with corresponding all-metallic structures.

  1. Single Bunch Wakefields in the CERN-PSI-ELETTRA X-band Linear Accelerator

    E-Print Network [OSTI]

    El-Ashmawy, Mostafa; Dehler, Micha; Raguin, Jean-Yves; Riddone, Germana; Zennaro, Riccardo

    2010-01-01T23:59:59.000Z

    FERMI@ELETTRA and PSI-XFEL are 4th Generation Light Sources that require high quality electron beam at the entrance of the undulator chains. In this context, a specially developed X-band structure with integrated alignment monitors will be used to mitigate the nonlinearities in the longitudinal phase space due to the second order RF time curvature and the second order momentum compaction term of chicane compressor. The knowledge of the transverse and longitudinal short range wakefields in the X-band structure is essential to evaluate the beam quality in terms of longitudinal energy spread and transverse kick spread. We have used the ABCI code to numerically evaluate the transverse and longitudinal wake potentials for short bunches in this structure

  2. Recent Progress at LBNL on Characterization of Laser Wakefield Accelerated Electron Bunches using Coherent Transition Radiation

    E-Print Network [OSTI]

    2007-01-01T23:59:59.000Z

    RECENT PROGRESS AT LBNL ON CHARACTERIZATION OF LASERBerkeley National Laboratory (LBNL), Berkeley, CA 94720,USA Abstract At LBNL, laser wake?eld accelerators (LWFA) can

  3. Drive Beam Shaping and Witness Bunch Generation for the Plasma Wakefield Accelerator

    SciTech Connect (OSTI)

    England, R. J.; Frederico, J.; Hogan, M. J. [SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States); Muggli, P. [University of Southern California, Los Angeles, CA 90089 (United States); Joshi, C. [University of California Los Angeles, Los Angeles, CA 90024 (United States)

    2010-11-04T23:59:59.000Z

    High transformer ratio operation of the plasma wake field accelerator requires a tailored drive beam current profile followed by a short witness bunch. We discuss techniques for generating the requisite dual bunches and for obtaining the desired drive beam profile, with emphasis on the FACET experiment at SLAC National Accelerator Laboratory.

  4. Development of high gradient laser wakefield accelerators towards nuclear detection applications at LBNL

    E-Print Network [OSTI]

    Geddes, Cameron GR

    2010-01-01T23:59:59.000Z

    detection applications at LBNL Cameron G.R. Geddes 1 , DavidLeemans 1,4 LOASIS Program, LBNL, 1 Cyclotron Rd MS 71-259,accelerator experiments at LBNL demonstrated narrow energy

  5. Undulator-Based Laser Wakefield Accelerator Electron Beam Energy Spread and Emittance Diagnostic

    SciTech Connect (OSTI)

    Bakeman, M.S.; Van Tilborg, J.; Nakamura, K.; Gonsalves, A.; Osterhoff, J.; Sokollik, T.; Lin, C.; Robinson, K.E.; Schroeder, C.B.; Toth, Cs.; Weingartner, R.; Gruner, F.; Esarey, E.; Leemans, W.P.

    2010-06-01T23:59:59.000Z

    The design and current status of experiments to couple the Tapered Hybrid Undulator (THUNDER) to the Lawrence Berkeley National Laboratory (LBNL) laser plasma accelerator (LPA) to measure electron beam energy spread and emittance are presented.

  6. Wake field in dielectric acceleration structures L. Schachter,1

    E-Print Network [OSTI]

    Byer, Robert L.

    particle accel- erators relies on dielectric slow-wave structures confining a laser field. Conceptually

  7. Transverse self-modulation of ultra-relativistic lepton beams in the plasma wakefield accelerator

    E-Print Network [OSTI]

    Vieira, J; Mori, W B; Silva, L O; Muggli, P

    2015-01-01T23:59:59.000Z

    The transverse self-modulation of ultra-relativistic, long lepton bunches in high-density plasmas is explored through full-scale particle-in-cell simulations. We demonstrate that long SLAC-type electron and positron bunches can become strongly self-modulated over centimeter distances, leading to wake excitation in the blowout regime with accelerating fields in excess of 20 GV/m. We show that particles energy variations exceeding 10 GeV can occur in meter-long plasmas. We find that the self-modulation of positively and negatively charged bunches differ when the blowout is reached. Seeding the self-modulation instability suppresses the competing hosing instability. This work reveals that a proof-of-principle experiment to test the physics of bunch self-modulation can be performed with available lepton bunches and with existing experimental apparatus and diagnostics.

  8. Visualizing Particle-in-Cell Simulation of Laser Wakefield Particle...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of times greater than those obtained in conventional particle accelerators. LWFAs use the electric field of a plasma wave - the wakefield - driven by the radiation pressure of an...

  9. Development of High-Gradient Dielectric Laser-Driven Particle Accelerator Structures

    SciTech Connect (OSTI)

    Byer, Robert L.

    2013-11-07T23:59:59.000Z

    The thrust of Stanford's program is to conduct research on high-gradient dielectric accelerator structures driven with high repetition-rate, tabletop infrared lasers. The close collaboration between Stanford and SLAC (Stanford Linear Accelerator Center) is critical to the success of this project, because it provides a unique environment where prototype dielectric accelerator structures can be rapidly fabricated and tested with a relativistic electron beam.

  10. Terahertz radiation as a bunch diagnostic for laser-wakefield-accelerated electron bunches

    SciTech Connect (OSTI)

    van Tilborg, Jeroen; Schroeder, Carl; Filip, Catalin; Toth, Csaba; Geddes, Cameron; Fubiani, Gwenael; Esarey, Eric; Leemans, Wim

    2011-06-17T23:59:59.000Z

    Experimental results are reported from two measurement techniques (semiconductor switching and electro-optic sampling) that allow temporal characterization of electron bunches produced by a laser-driven plasma-based accelerator. As femtosecond electron bunches exit the plasma-vacuum interface, coherent transition radiation (at THz frequencies) is emitted. Measuring the properties of this radiation allows characterization of the electron bunches. Theoretical work on the emission mechanism is presented, including a model that calculates the THz wave form from a given bunch profile. It is found that the spectrum of the THz pulse is coherent up to the 200 {micro}m thick crystal (ZnTe) detection limit of 4 THz, which corresponds to the production of sub-50 fs (rms) electron bunch structure. The measurements demonstrate both the shot-to-shot stability of bunch parameters that are critical to THz emission (such as total charge and bunch length), as well as femtosecond synchronization among bunch, THz pulse, and laser beam.

  11. X-ray phase contrast imaging of biological specimens with femtosecond pulses of betatron radiation from a compact laser plasma wakefield accelerator

    SciTech Connect (OSTI)

    Kneip, S. [Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom); Center for Ultrafast Optical Science, University of Michigan, Ann Arbor 48109 (United States); McGuffey, C.; Dollar, F.; Chvykov, V.; Kalintchenko, G.; Krushelnick, K.; Maksimchuk, A.; Mangles, S. P. D.; Matsuoka, T.; Schumaker, W.; Thomas, A. G. R.; Yanovsky, V. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor 48109 (United States); Bloom, M. S.; Najmudin, Z.; Palmer, C. A. J.; Schreiber, J. [Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom)

    2011-08-29T23:59:59.000Z

    We show that x-rays from a recently demonstrated table top source of bright, ultrafast, coherent synchrotron radiation [Kneip et al., Nat. Phys. 6, 980 (2010)] can be applied to phase contrast imaging of biological specimens. Our scheme is based on focusing a high power short pulse laser in a tenuous gas jet, setting up a plasma wakefield accelerator that accelerates and wiggles electrons analogously to a conventional synchrotron, but on the centimeter rather than tens of meter scale. We use the scheme to record absorption and phase contrast images of a tetra fish, damselfly and yellow jacket, in particular highlighting the contrast enhancement achievable with the simple propagation technique of phase contrast imaging. Coherence and ultrafast pulse duration will allow for the study of various aspects of biomechanics.

  12. Use of dielectric material in muon accelerator RF cavities

    E-Print Network [OSTI]

    French, Katheryn Decker

    2011-01-01T23:59:59.000Z

    The building of a muon collider is motivated by the desire to collide point-like particles while reducing the limitations imposed by synchrotron radiation. The many challenges unique to muon accelerators are derived from ...

  13. Upgrade of the Drive LINAC for the AWA Facility Dielectric Two-Beam Accelerator

    SciTech Connect (OSTI)

    Power, John; /Argonne; Conde, Manoel; /Argonne; Gai, Wei; /Argonne; Li, Zenghai; /SLAC; Mihalcea, Daniel; /Northern Illinois U.

    2012-07-02T23:59:59.000Z

    We report on the design of a seven-cell, standing-wave, 1.3-GHz rf cavity and the associated beam dynamics studies for the upgrade of the drive beamline LINAC at the Argonne Wakefield Accelerator (AWA) facility. The LINAC design is a compromise between single-bunch operation (100 nC {at} 75 MeV) and minimization of the energy droop along the bunch train during bunch-train operation. The 1.3-GHz drive bunch-train target parameters are 75 MeV, 10-20-ns macropulse duration, and 16 x 60 nC microbunches; this is equivalent to a macropulse current and beam power of 80 A and 6 GW, respectively. Each LINAC structure accelerates approximately 1000 nC in 10 ns by a voltage of 11 MV at an rf power of 10 MW. Due to the short bunch-train duration desired ({approx}10 ns) and the existing frequency (1.3 GHz), compensation of the energy droop along the bunch train is difficult to accomplish by means of the two standard techniques: time-domain or frequency-domain beam loading compensation. Therefore, to minimize the energy droop, our design is based on a large stored energy rf cavity. In this paper, we present our rf cavity optimization method, detailed rf cavity design, and beam dynamics studies of the drive beamline.

  14. Characterization and Application of Hard X-Ray Betatron Radiation Generated by Relativistic Electrons from a Laser-Wakefield Accelerator

    E-Print Network [OSTI]

    Schnell, Michael; Uschmann, Ingo; Jansen, Oliver; Kaluza, Malte Christoph; Spielmann, Christian

    2015-01-01T23:59:59.000Z

    The necessity for compact table-top x-ray sources with higher brightness, shorter wavelength and shorter pulse duration has led to the development of complementary sources based on laser-plasma accelerators, in contrast to conventional accelerators. Relativistic interaction of short-pulse lasers with underdense plasmas results in acceleration of electrons and in consequence in the emission of spatially coherent radiation, which is known in the literature as betatron radiation. In this article we report on our recent results in the rapidly developing field of secondary x-ray radiation generated by high-energy electron pulses. The betatron radiation is characterized with a novel setup allowing to measure the energy, the spatial energy distribution in the far-field of the beam and the source size in a single laser shot. Furthermore, the polarization state is measured for each laser shot. In this way the emitted betatron x-rays can be used as a non-invasive diagnostic tool to retrieve very subtle information of t...

  15. Parameter sensitivity of plasma wakefields driven by self-modulating proton beams

    SciTech Connect (OSTI)

    Lotov, K. V.; Minakov, V. A.; Sosedkin, A. P. [Budker Institute of Nuclear Physics SB RAS, 630090 Novosibirsk, Russia and Novosibirsk State University, 630090 Novosibirsk (Russian Federation)

    2014-08-15T23:59:59.000Z

    The dependence of wakefield amplitude and phase on beam and plasma parameters is studied in the parameter area of interest for self-modulating proton beam-driven plasma wakefield acceleration. The wakefield phase is shown to be extremely sensitive to small variations of the plasma density, while sensitivity to small variations of other parameters is reasonably low. The study of large parameter variations clarifies the effects that limit the achievable accelerating field in different parts of the parameter space: nonlinear elongation of the wakefield period, insufficient charge of the drive beam, emittance-driven beam divergence, and motion of plasma ions.

  16. Plasma Wakefield Experiments at FACET

    SciTech Connect (OSTI)

    Hogan, M.J.; England, R.J.; Frederico, J.; Hast, C.; Li, S.Z.; Litos, M.; Walz, D.; /SLAC; An, W.; Clayton, C.E.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.; Tochitsky, S.; /UCLA; Muggli, P.; Pinkerton, S.; Shi, Y.; /Southern California U.

    2011-08-19T23:59:59.000Z

    FACET, the Facility for Advanced Accelerator and Experimental Tests, is a new facility being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration beginning in summer 2011. The nominal FACET parameters are 23GeV, 3nC electron bunches compressed to {approx}20{micro}m long and focused to {approx}10{micro}m wide. The intense fields of the FACET bunches will be used to field ionize neutral lithium or cesium vapor produced in a heat pipe oven. Previous experiments at the SLAC FFTB facility demonstrated 50GeV/m gradients in an 85cm field ionized lithium plasma where the interaction distance was limited by head erosion. Simulations indicate the lower ionization potential of cesium will decrease the rate of head erosion and increase single stage performance. The initial experimental program will compare the performance of lithium and cesium plasma sources with single and double bunches. Later experiments will investigate improved performance with a pre-ionized cesium plasma. The status of the experiments and expected performance are reviewed. The FACET Facility is being constructed in sector 20 of the SLAC linac primarily to study beam driven plasma wakefield acceleration. The facility will begin commissioning in summer 2011 and conduct an experimental program over the coming five years to study electron and positron beam driven plasma acceleration with strong wake loading in the non-linear regime. The FACET experiments aim to demonstrate high-gradient acceleration of electron and positron beams with high efficiency and negligible emittance growth.

  17. Results from Plasma Wakefield Experiments at FACET

    SciTech Connect (OSTI)

    Li, S.Z.; Clarke, C.I.; England, R.J.; Frederico, J.; Gessner, S.J.; Hogan, M.J.; Jobe, R.K.; Litos, M.D.; Walz, D.R.; /SLAC; Muggli, P.; /Munich, Max Planck Inst.; An, W.; Clayton, C.E.; Joshi, C.; Lu, W.; Marsh, K.A.; Mori, W.; Tochitsky, S.; /UCLA; Adli, E.; /U. Oslo

    2011-12-13T23:59:59.000Z

    We report initial results of the Plasma Wakefield Acceleration (PWFA) Experiments performed at FACET - Facility for Advanced aCcelertor Experimental Tests at SLAC National Accelerator Laboratory. At FACET a 23 GeV electron beam with 1.8 x 10{sup 10} electrons is compressed to 20 {mu}m longitudinally and focused down to 10 {mu}m x 10 {mu}m transverse spot size for user driven experiments. Construction of the FACET facility completed in May 2011 with a first run of user assisted commissioning throughout the summer. The first PWFA experiments will use single electron bunches combined with a high density lithium plasma to produce accelerating gradients > 10 GeV/m benchmarking the FACET beam and the newly installed experimental hardware. Future plans for further study of plasma wakefield acceleration will be reviewed. The experimental hardware and operation of the plasma heat-pipe oven have been successfully commissioned. Plasma wakefield acceleration was not observed because the electron bunch density was insufficient to ionize the lithium vapor. The remaining commissioning time in summer 2011 will be dedicated to delivering the FACET design parameters for the experimental programs which will begin in early 2012. PWFA experiments require the shorter bunches and smaller transverse sizes to create the plasma and drive large amplitude wakefields. Low emittance and high energy will minimize head erosion which was found to be a limiting factor in acceleration distance and energy gain. We will run the PWFA experiments with the design single bunch conditions in early 2012. Future PWFA experiments at FACET are discussed in [5][6] and include drive and witness bunch production for high energy beam manipulation, ramped bunch to optimize tranformer ratio, field-ionized cesium plasma, preionized plasmas, positron acceleration, etc.. We will install a notch collimator for two-bunch operation as well as new beam diagnostics such as the X-band TCAV [7] to resolve the two bunches. With these new instruments and desired beam parameters in place next year, we will be able to complete the studies of plasma wakefield acceleration in the next few years.

  18. Tailored electron bunches with smooth current profiles for enhanced transformer ratios in beam-driven acceleration

    E-Print Network [OSTI]

    Lemery, Francois

    2015-01-01T23:59:59.000Z

    Collinear high-gradient ${\\cal O} (GV/m)$ beam-driven wakefield methods for charged-particle acceleration could be critical to the realization of compact, cost-efficient, accelerators, e.g., in support of TeV-scale lepton colliders or multiple-user free-electron laser facilities. To make these options viable, the high accelerating fields need to be complemented with large transformer ratios $>2$, a parameter characterizing the efficiency of the energy transfer between a wakefield-exciting "drive" bunch to an accelerated "witness" bunch. While several potential current distributions have been discussed, their practical realization appears challenging due to their often discontinuous nature. In this paper we propose several alternative current profiles which are smooth which also lead to enhanced transformer ratios. We especially explore a laser-shaping method capable of generating one the suggested distributions directly out of a photoinjector and discuss a linac concept that could possible drive a dielectric ...

  19. Dielectric

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign: Potential ApplicationYu, JamesDiamondoidDianneDielectric

  20. Accelerating Particles with Plasma

    SciTech Connect (OSTI)

    Litos, Michael; Hogan, Mark

    2014-11-05T23:59:59.000Z

    Researchers at SLAC explain how they use plasma wakefields to accelerate bunches of electrons to very high energies over only a short distance. Their experiments offer a possible path for the future of particle accelerators.

  1. Beam dynamics and wakefield suppression in interleaved damped and detuned structures for CLIC

    E-Print Network [OSTI]

    D'Elia, A; Khan, V F; Jones, R M; Latina, A; Nesmiyan, I; Riddone, G

    2013-01-01T23:59:59.000Z

    Acceleration of multiple bunches of charged particles in the main linacs of the Compact Linear Collider (CLIC) with high accelerating fields provides two major challenges: firstly, to ensure the surface electromagnetic fields do not cause electrical breakdown and subsequent surface damage, and secondly, to ensure the beam-excited wakefields are sufficiently suppressed to avoid appreciable emittance dilution. In the baseline design for CLIC, heavy wakefield suppression is used (Q ~ 10) [1] and this ensures the beam quality is well-preserved [2]. Here we discuss an alternative means to suppress the wakefield which relies on strong detuning of the cell dipole frequencies, together with moderate damping, effected by manifolds which are slot-coupled to each accelerating cell. This damped and detuned wakefield suppression scheme is based on the methodology developed for the Japanese Linear Collider/Next Linear Collider (JLC/NLC) [3]. Here we track the multi-bunch beam down the complete collider, u...

  2. Recent Experiment on Wakefield Transformer Ratio Enhancement at AWA

    SciTech Connect (OSTI)

    Jing, C.; Kanareykin, A. [Euclid Techlabs, LLC, 5900 Harper Rd, Solon, OH 44139 (United States); High Energy Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Power, J. G.; Conde, M.; Liu, W.; Yusof, Z.; Gai, W. [High Energy Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2010-11-04T23:59:59.000Z

    One technique to enhance the transformer ratio beyond the ordinary limit of 2 in a collinear wakefield acceleration scheme is to use a ramped bunched train (RBT). The first experimental demonstration has been reported in [1]. However, due to the mismatch between the beam bunch length and frequency of the accelerating structure, the observed transformer ratio was only marginally above 2 in the earlier experiment. We recently revisited this experiment with an optimized bunch length using the laser stacking technique at Argonne Wakefield Accelerator (AWA) facility. A transformer ratio of 3.4 has been measured using two drive bunches. Attempting to use four drive bunches met with major challenges. In this article, measurement results and data analysis from these experiments are presented in detail.

  3. all-dielectric electron accelerator: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    are byproducts of the acceleration process. CHARGE DIAGNOSTICS Integrating Current Transformers (ICTs) have of their ease of use, precision and non invasiveness. More recently,...

  4. Wakefield effects of the bypass line in LCLS-II

    E-Print Network [OSTI]

    Bane, K

    2014-01-01T23:59:59.000Z

    In LCLS-II, after acceleration and compression and just before entering the undulator, the beam passes through 2.5 km of 24.5 mm (radius) stainless steel pipe. The bunch that passes through the pipe is extremely short---with an rms of 8 um for the nominal 100 pC case. Thus, even though the pipe has a large aperture, the wake that applies is the {\\it short-range} resistive wall wakefield. The bunch distribution is approximately uniform, and therefore the wake induced voltage is characterized by a rather linear voltage chirp. It turns out that the wake supplies needed dechirping to the LCLS-II beam before it enters the undulator. In this note we calculate the wake, discuss the confidence in the calculation, and investigate how to improve the induced chirp linearity and/or strength. Finally, we also study the strength and effects of the transverse (dipole) resistive wall wakefield.

  5. Wakefield measurements of SLAC linac structures at the Argonne AATF

    SciTech Connect (OSTI)

    Wang, J.W.; Loew, G.A. (Stanford Linear Accelerator Center, Menlo Park, CA (USA)); Simpson, J.; Chojnacki, E.; Gai, W.; Konecny, R.; Schoessow, P. (Argonne National Lab., IL (USA))

    1991-05-01T23:59:59.000Z

    Damped and detuned linac structures designed to minimize the effects of wakefields excited by e{sup {plus minus}} bunch trains in future linear colliders are presently under investigation at SLAC. This paper describes the results of measurements of both longitudinal and transverse wakefields performed at the ANL Advanced Accelerator Test Facility with two SLAC-built X-Band disk-loaded waveguides: a conventional 30-cavity long constant-impedance structure and a non-conventional 50-cavity long structure along which the iris and spacer diameters have been varied so as to stagger-tune the HEM{sub 11} mode frequency by 37%. The results are shown to be in excellent agreement with computations made by KN7C, TRANSVRS, TBCI, and LINACBBU. 8 refs., 5 figs.

  6. Design of a subnanometer resolution beam position monitor for dielectric laser accelerators

    E-Print Network [OSTI]

    Byer, Robert L.

    of the first laser-powered particle accel- erators "on a chip" [1,2]. These devices are specifically designed present a new concept for a beam position monitor with the unique ability to map particle beam position, this device is ideal for future x-ray sources and laser-driven particle accelerators "on a chip." © 2012

  7. Computational studies and optimization of wakefield accelerators

    E-Print Network [OSTI]

    Geddes, C.G.R.

    2010-01-01T23:59:59.000Z

    France [1] ILC- www.linearcollider.org/cms ; LCLS- www-ssrl.slac.stanford.edu/lcls/ [2] T. Tajima and J. M. Dawson,while machines such as the LCLS will use km-scale linacs to

  8. Laser Wakefield Particle Accelerators Project at NERSC

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is Your Home asLCLSLaboratoryRowlandRevolutionizingLaser

  9. Extremely short relativistic-electron-bunch generation in the laser wakefield via novel bunch injection scheme

    E-Print Network [OSTI]

    Strathclyde, University of

    Extremely short relativistic-electron-bunch generation in the laser wakefield via novel bunch accelerator (LWFA) a short in- tense laser pulse, with a duration on the order of a plasma wave period July 2004; published 6 December 2004) Recently a new electron-bunch injection scheme for the laser

  10. Automated analysis for detecting beams in laser wakefield simulations

    SciTech Connect (OSTI)

    Ushizima, Daniela M.; Rubel, Oliver; Prabhat, Mr.; Weber, Gunther H.; Bethel, E. Wes; Aragon, Cecilia R.; Geddes, Cameron G.R.; Cormier-Michel, Estelle; Hamann, Bernd; Messmer, Peter; Hagen, Hans

    2008-07-03T23:59:59.000Z

    Laser wakefield particle accelerators have shown the potential to generate electric fields thousands of times higher than those of conventional accelerators. The resulting extremely short particle acceleration distance could yield a potential new compact source of energetic electrons and radiation, with wide applications from medicine to physics. Physicists investigate laser-plasma internal dynamics by running particle-in-cell simulations; however, this generates a large dataset that requires time-consuming, manual inspection by experts in order to detect key features such as beam formation. This paper describes a framework to automate the data analysis and classification of simulation data. First, we propose a new method to identify locations with high density of particles in the space-time domain, based on maximum extremum point detection on the particle distribution. We analyze high density electron regions using a lifetime diagram by organizing and pruning the maximum extrema as nodes in a minimum spanning tree. Second, we partition the multivariate data using fuzzy clustering to detect time steps in a experiment that may contain a high quality electron beam. Finally, we combine results from fuzzy clustering and bunch lifetime analysis to estimate spatially confined beams. We demonstrate our algorithms successfully on four different simulation datasets.

  11. Beam manipulation by self-wakefield at ATF

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Committee and the ATF Users' Meetings, April 26 - 27, 2012 Outline 1. Enhanced Transformer Ratio demonstration (wakefield mapping with the shaped beam) 2. Tunable beam energy...

  12. Wakefield Municipal Gas and Light Department- Residential Conservation Services Program

    Broader source: Energy.gov [DOE]

    The Wakefield Municipal Gas and Light Department (WMGLD), in cooperation with the Massachusetts Municipal Wholesale Electric Company (MMWEC), offers the "Incentive Rebate Program" to encourage...

  13. Dielectric-wall linear accelerator with a high voltage fast rise time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators

    DOE Patents [OSTI]

    Caporaso, G.J.; Sampayan, S.E.; Kirbie, H.C.

    1998-10-13T23:59:59.000Z

    A dielectric-wall linear accelerator is improved by a high-voltage, fast rise-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface. 12 figs.

  14. Plasma wakefields in the quasi-nonlinear regime: Experiments at ATF

    SciTech Connect (OSTI)

    Rosenzweig, J. B.; Andonian, G.; Barber, S.; Ferrario, M.; Muggli, P.; O'Shea, B.; Sakai, Y.; Valloni, A.; Williams, O.; Xi, Y.; Yakimenko, V. [UCLA Dept. of Physics and Astronomy, 405 Hilgard Ave. Los Angeles, CA, 90095 (United States); Accelerator Division, Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Frascati , Via E. Fermi 40, Frascati (RM) 00044 (Italy); Max Planck Institute for Physics, Munich (Germany); UCLA Dept. of Physics and Astronomy, 405 Hilgard Ave. Los Angeles, CA, 90095 (United States); Brookhaven National Laboratory, Upton, NY, 11973 (United States)

    2012-12-21T23:59:59.000Z

    In this work we present details of planned experiments to investigate certain aspects of the quasi non linear regime (QNL) of plasma wakefield acceleration (PWFA). In the QNL regime it is, in principal, possible to combine the benefits of both nonlinear and linear PWFA. That is, beams of high quality can be maintained through acceleration due to the complete ejection of plasma electrons from beam occupied region, while large energy gains can be achieved through use of transformer ratio increasing schemes, such as ramped bunch trains. With the addition of an short focal length PMQ triplet capable of focusing beams to the few micron scale and the ability to generate tunable bunch trains, the Accelerator Test Facility (ATF) at Brookhaven National Lab offers the unique capabilities to probe these characteristics of the QNL regime.

  15. Recent Advances in Plasma Acceleration

    SciTech Connect (OSTI)

    Hogan, Mark

    2007-03-19T23:59:59.000Z

    The costs and the time scales of colliders intended to reach the energy frontier are such that it is important to explore new methods of accelerating particles to high energies. Plasma-based accelerators are particularly attractive because they are capable of producing accelerating fields that are orders of magnitude larger than those used in conventional colliders. In these accelerators a drive beam, either laser or particle, produces a plasma wave (wakefield) that accelerates charged particles. The ultimate utility of plasma accelerators will depend on sustaining ultra-high accelerating fields over a substantial length to achieve a significant energy gain. More than 42 GeV energy gain was achieved in an 85 cm long plasma wakefield accelerator driven by a 42 GeV electron drive beam in the Final Focus Test Beam (FFTB) Facility at SLAC. Most of the beam electrons lose energy to the plasma wave, but some electrons in the back of the same beam pulse are accelerated with a field of {approx}52 GV/m. This effectively doubles their energy, producing the energy gain of the 3 km long SLAC accelerator in less than a meter for a small fraction of the electrons in the injected bunch. Prospects for a drive-witness bunch configuration and high-gradient positron acceleration experiments planned for the SABER facility will be discussed.

  16. Automatic Beam Path Analysis of Laser Wakefield Particle Acceleration Data

    E-Print Network [OSTI]

    Rubel, Oliver

    2010-01-01T23:59:59.000Z

    Without compression, the size of a bitmap index increasesnumber of bitmaps per index. Compression is used to reduceindex software called FastBit [9]. It implements the fastest known bitmap compression

  17. ATF Plasma Sources for Wakefield Electron Acceleration ATF User...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Plasma Sources at ATF Ablative discharge capillary Gas-filled capillary Gas jet Plasma Sources: Ablative discharge capillary +20 kV DC 1k 1M HV generator (20kV,...

  18. Modeling laser wakefield accelerators in a Lorentz boosted frame

    E-Print Network [OSTI]

    Vay, J.-L.

    2010-01-01T23:59:59.000Z

    1:2:4) Mean beam position (m) VAX Sen c >SA- i— s( i) c 3- a2) - - - S(1:2:3)! S(1:2:4); VAX c c 3 0J u xi E2i SO) S(l:4) Mean beam position (m) VAX Figure 20: (left) Average beam

  19. Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of experiments on new lasers such as BELLA. Principal Investigator: Cameron Geddes, LBNL More Information: See J.-L. Vay, C. G. R. Geddes, E. Cormier-Michel, and D. P. Grote,...

  20. Analysis of Laser Wakefield Particle Acceleration Data at NERSC

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Data LWFAIllustrationSmall.png In collaboration with researchers of the LOASIS program (LBNL) and the SciDAC SDM center (LBNL) we have been working on various efforts aimed at...

  1. UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC

    E-Print Network [OSTI]

    Bakeman, M.S.

    2010-01-01T23:59:59.000Z

    ultra-short, high-peak- current, electron beams are ideal for driving a compact XUV free electron laser (

  2. Modeling Laser Wakefield Accelerators in a Lorentz Boosted Frame

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your1 SECTION A.Model Verification andModeling Laser

  3. Summary Report of Working Group 1: Laser-Plasma Acceleration

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    structure providing a linear mechanism with potential to harness low-energy laser systems [11 orders beyond conventional machines, with quasi-monoenergetic beams at MeV-GeV energies, making them and diagnostics. This includes laser wakefield acceleration [1], where acceleration by a plasma wave excited

  4. Powerful, pulsed, THz radiation from laser accelerated relativistic electron bunches

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    by strongly focused ( 6 µm), high peak power (up to 10 TW), ultra-short ( 50 fs) laser pulses of a 10 Hz at the exit of the plasma accelerator. Keywords: ultrahigh-fields, ultra-short, laser-plasma, wakefieldPowerful, pulsed, THz radiation from laser accelerated relativistic electron bunches Cs. T´otha, J

  5. Experimental demonstration of wakefield effects in a THz planar...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Change in D-W spacing energy gainloss of a witness Wakefield structure c b (c) * Polycrystalline diamond, 75um thick * 250 GHz slab-symmetrical structure Why Diamond...

  6. Physics of laser-driven plasma-based electron accelerators E. Esarey, C. B. Schroeder, and W. P. Leemans

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Physics of laser-driven plasma-based electron accelerators E. Esarey, C. B. Schroeder, and W. P Laser-driven plasma-based accelerators, which are capable of supporting fields in excess of 100 GV/m, are reviewed. This includes the laser wakefield accelerator, the plasma beat wave accelerator, the self

  7. AUGMENTING COMPUTER MUSIC WITH JUST-IN-TIME COMPILATION Wesley Smith, Graham Wakefield

    E-Print Network [OSTI]

    California at Santa Barbara, University of

    AUGMENTING COMPUTER MUSIC WITH JUST-IN-TIME COMPILATION Wesley Smith, Graham Wakefield University of California Santa Barbara Media Arts and Technology whsmith|wakefield@mat.ucsb.edu ABSTRACT We discuss

  8. MuSiC: a Multibunch and multiparticle Simulation Code with an alternative approach to wakefield effects

    E-Print Network [OSTI]

    Migliorati, M

    2015-01-01T23:59:59.000Z

    The simulation of beam dynamics in presence of collective effects requires a strong computational effort to take into account, in a self consistent way, the wakefield acting on a given charge and produced by all the others. Generally this is done by means of a convolution integral or sum. Moreover, if the electromagnetic fields consist of resonant modes with high quality factors, responsible, for example, of coupled bunch instabilities, a charge is also affected by itself in previous turns, and a very long record of wakefield must be properly taken into account. In this paper we present a new simulation code for the longitudinal beam dynamics in a circular accelerator, which exploits an alternative approach to the currently used convolution sum, reducing the computing time and avoiding the issues related to the length of wakefield for coupled bunch instabilities. With this approach it is possible to simulate, without the need of a large computing power, simultaneously, the single and multi-bunch beam dynamics...

  9. BNL | ATF Specialized Instrumentation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Chamber Electron-plasma Interaction Chamber Plasma Density Diagnostic Dielectric Wakefield Acceleration (DWFA) Chamber Laser Injection Vacuum Chamber Ion Generation Vacuum Vessel...

  10. RF cavity using liquid dielectric for tuning and cooling

    DOE Patents [OSTI]

    Popovic, Milorad (Warrenville, IL); Johnson, Rolland P. (Newport News, VA)

    2012-04-17T23:59:59.000Z

    A system for accelerating particles includes an RF cavity that contains a ferrite core and a liquid dielectric. Characteristics of the ferrite core and the liquid dielectric, among other factors, determine the resonant frequency of the RF cavity. The liquid dielectric is circulated to cool the ferrite core during the operation of the system.

  11. Shielding effect and wakefield pattern of a moving test charge in a non-Maxwellian dusty plasma

    SciTech Connect (OSTI)

    Ali, S. [National Centre for Physics (NCP), Quaid-e-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan)] [National Centre for Physics (NCP), Quaid-e-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Khan, S. [National Centre for Physics (NCP), Quaid-e-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan) [National Centre for Physics (NCP), Quaid-e-Azam University Campus, Shahdra Valley Road, Islamabad 44000 (Pakistan); Department of Physics, Gomal University, Dera Ismail Khan 29050 (Pakistan)

    2013-07-15T23:59:59.000Z

    By using the Vlasov-Poisson equations, we calculate an expression for the electrostatic potential caused by a test charge in an unmagnetized non-Maxwellian dusty plasma, whose constituents are the superthermal hot-electrons, the mobile cold-electrons with a neutralizing background of cold ions, and charge fluctuating isolated dust grains. The superthermality effects due to hot electrons not only modify the dielectric constant of the electron-acoustic waves but also significantly affect the electrostatic potential. The latter can be decomposed into the Debye-Hückel and oscillatory wake potentials. Analytical and numerical results reveal that the Debye-Hückel and wakefield potentials converge to the Maxwellian case for large values of superthermality parameter. Furthermore, the plasma parameters play a vital role in the formation of shielding and wakefield pattern in a two-electron temperature plasma. The present results should be important for laboratory and space dusty plasmas, where hot-electrons can be assumed to follow the non-Maxwellian distribution function.

  12. USING LUA FOR AUDIOVISUAL COMPOSTION Graham Wakefield Wesley Smith

    E-Print Network [OSTI]

    California at Santa Barbara, University of

    USING LUA FOR AUDIOVISUAL COMPOSTION Graham Wakefield Wesley Smith University of California Santa Barbara Media Arts and Technology Program Santa Barbara, California, USA ABSTRACT In this paper, we/MSP/Jitter [27], PureData [19], etc.) are popular choices for composing interactive digital media works because

  13. Wakefield Calculations for the LCLS in Multbunch Operation

    SciTech Connect (OSTI)

    Bane, K; /SLAC

    2011-10-17T23:59:59.000Z

    Normally the Linac Coherent Light Source (LCLS) operates in single-bunch mode, sending a bunch of up to 250 pC charge at 120 Hz through the linac and the undulator, and the resulting FEL radiation into one of the experimental hutches. With two bunches per rf pulse, each pulse could feed either two experiments or one experiment in a pump-probe type configuration. Two-bunch FEL operation has already been briefly tested at the LCLS, and works reasonably well, although not yet routinely. In this report we study the longitudinal and transverse long-range (bunch-to-bunch) wakefields of the linacs and their effects on LCLS performance in two-bunch mode, which is initially the most likely scenario. The longitudinal wake changes the average energy at the second bunch, and the transverse wake misaligns the second bunch (in transverse phase space) in the presence of e.g. transverse injection jitter or quad misalignments. Finally, we extend the study to consider the LCLS with trains of up to 20 bunches per rf pulse. In the LCLS the bunch is created in an rf gun, and then passes in sequence through Linac 0, Linac 1, Linac X, Bunch Compressor 1 (BC 1), Linac 2, BC 2, Linac 3, and finally the undulator. In the process the bunch energy reaches 13.5 GeV and peak current 3 kA. In Table 1 we present some machine and beam parameters in three of the linacs that we will use in the calculations: initial beam energy E{sub 0}, total accelerator length L, average beta function {beta}{sub y}, bunch peak current I, and rf phase (with respect to crest) {phi}; the final energy of a linac equals E{sub 0} of the following linac, and in Linac 3 is E{sub f} = 13.5 GeV. (The X-band linac, with L = 60 cm, has wake effects that are small compared to the other linacs, and will not be discussed.) In this report we limit our study to trains of equally populated, equally spaced bunches with a total length of less than 100 ns. The charge of each bunch is eN{sub b} = 250 pC.

  14. Muon acceleration in cosmic-ray sources

    SciTech Connect (OSTI)

    Klein, Spencer R.; Mikkelsen, Rune E. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Becker Tjus, Julia [Fakultät für Physik and Astronomie, Theoretische Physik I, Ruhr-Universität Bochum, D-44780 Bochum (Germany)

    2013-12-20T23:59:59.000Z

    Many models of ultra-high energy cosmic-ray production involve acceleration in linear accelerators located in gamma-ray bursts, magnetars, or other sources. These transient sources have short lifetimes, which necessitate very high accelerating gradients, up to 10{sup 13} keV cm{sup –1}. At gradients above 1.6 keV cm{sup –1}, muons produced by hadronic interactions undergo significant acceleration before they decay. This muon acceleration hardens the neutrino energy spectrum and greatly increases the high-energy neutrino flux. Using the IceCube high-energy diffuse neutrino flux limits, we set two-dimensional limits on the source opacity and matter density, as a function of accelerating gradient. These limits put strong constraints on different models of particle acceleration, particularly those based on plasma wake-field acceleration, and limit models for sources like gamma-ray bursts and magnetars.

  15. Facility for Advanced Accelerator Experimental Tests (FACET) at SLAC and its Radiological Considerations

    SciTech Connect (OSTI)

    Mao, X.S.; Leitner, M.Santana; Vollaire, J.

    2011-08-22T23:59:59.000Z

    Facility for Advanced Accelerator Experimental Tests (FACET) in SLAC will be used to study plasma wakefield acceleration. FLUKA Monte Carlo code was used to design a maze wall to separate FACET project and LCLS project to allow persons working in FACET side during LCLS operation. Also FLUKA Monte Carlo code was used to design the shielding for FACET dump to get optimum design for shielding both prompt and residual doses, as well as reducing environmental impact. FACET will be an experimental facility that provides short, intense pulses of electrons and positrons to excite plasma wakefields and study a variety of critical issues associated with plasma wakefield acceleration [1]. This paper describes the FACET beam parameters, the lay-out and its radiological issues.

  16. Muon Acceleration in Cosmic-ray Sources

    E-Print Network [OSTI]

    Spencer R. Klein; Rune Mikkelsen; Julia K. Becker Tjus

    2012-08-09T23:59:59.000Z

    Many models of ultra-high energy cosmic-ray production involve acceleration in linear accelerators located in Gamma-Ray Bursts magnetars, or other sources. These source models require very high accelerating gradients, $10^{13}$ keV/cm, with the minimum gradient set by the length of the source. At gradients above 1.6 keV/cm, muons produced by hadronic interactions undergo significant acceleration before they decay. This acceleration hardens the neutrino energy spectrum and greatly increases the high-energy neutrino flux. We rule out many models of linear acceleration, setting strong constraints on plasma wakefield accelerators and on models for sources like Gamma Ray Bursts and magnetars.

  17. Optimization of the LCLS X-ray FEL output performance in the presence of strong undulator wakefields

    E-Print Network [OSTI]

    Reiche, S; Emma, P; Fawley, W M; Huang, Z; Nuhn, H D; Stupakov, G V

    2005-01-01T23:59:59.000Z

    Optimization of the LCLS X-ray FEL output performance in the presence of strong undulator wakefields

  18. Observation of Wakefields and Resonances in Coherent Synchrotron Radiation

    E-Print Network [OSTI]

    Billinghurst, B E; Baribeau, C; Batten, T; Dallin, L; May, T E; Vogt, J M; Wurtz, W A; Warnock, R; Bizzizero, D A; Kramer, S

    2015-01-01T23:59:59.000Z

    We report on high resolution measurements of resonances in the spectrum of coherent synchrotron radiation (CSR) at the Canadian Light Source (CLS). The resonances permeate the spectrum at wavenumber intervals of $0.074 ~\\textrm{cm}^{-1}$, and are highly stable under changes in the machine setup (energy, bucket filling pattern, CSR in bursting or continuous mode). Analogous resonances were predicted long ago in an idealized theory as eigenmodes of a smooth toroidal vacuum chamber driven by a bunched beam moving on a circular orbit. A corollary of peaks in the spectrum is the presence of pulses in the wakefield of the bunch at well defined spatial intervals. Through experiments and further calculations we elucidate the resonance and wakefield mechanisms in the CLS vacuum chamber, which has a fluted form much different from a smooth torus. The wakefield is observed directly in the 30-110 GHz range by RF diodes, and indirectly by an interferometer in the THz range. The wake pulse sequence found by diodes is less ...

  19. Wakefield Induced Correlated Energy Spread and Emittance Growth at TTF FEL

    E-Print Network [OSTI]

    1 Wakefield Induced Correlated Energy Spread and Emittance Growth at TTF FEL Feng ZHOU DESY) at DESY. During FEL operations, the longitudinal and transverse wakefields which are generated by vacuum and emittance growth at the TTF FEL of phase I and II. 1 Introduction The Free Electron Laser at the TESLA Test

  20. Stable laser–plasma accelerators at low densities

    SciTech Connect (OSTI)

    Li, Song; Hafz, Nasr A. M., E-mail: nasr@sjtu.edu.cn; Mirzaie, Mohammad; Ge, Xulei; Sokollik, Thomas; Chen, Min; Sheng, Zhengming; Zhang, Jie, E-mail: jzhang1@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2014-07-28T23:59:59.000Z

    We report stable laser wakefield acceleration using 17–50 TW laser pulses interacting with 4?mm-long helium gas jet. The initial laser spot size was relatively large (28??m) and the plasma densities were 0.48–2.0?×?10{sup 19?}cm{sup ?3}. High-quality 100–MeV electron beams were generated at the plasma density of 7.5?×?10{sup 18?}cm{sup ?3}, at which the beam parameters (pointing angle, energy spectrum, charge, and divergence angle) were measured and stabilized. At higher densities, filamentation instability of the laser-plasma interaction was observed and it has led to multiple wakefield accelerated electron beams. The experimental results are supported by 2D particle-in-cell simulations. The achievement presented here is an important step toward the use of laser-driven accelerators in real applications.

  1. Proposed dielectric-based microstructure laser-driven undulator T. Plettner and R. L. Byer

    E-Print Network [OSTI]

    Byer, Robert L.

    by the possibility of future dielectric-based laser-driven particle accelerators that are expected to produce GeV=m accel- eration gradients accompanied by a low-emittance, low- energy spread, and high-repetition rate electron sources [8,9] as well as for dielectric-structure laser-driven particle accelerators are underway

  2. Collimator Wakefield Calculations for ILC-TRC Report(LCC-0101)

    SciTech Connect (OSTI)

    Tenenbaum, P

    2003-10-07T23:59:59.000Z

    We summarize the formalism of collimator wakefields and their effect on beams that are near the center of the collimator gap, and apply the formalism to the TESLA, NLC, and CLIC collimation systems.

  3. Comparative Wakefield Analysis of a First Prototype of a DDS Structure for CLIC Main Linac

    E-Print Network [OSTI]

    D'Elia, A; Khan, V F; Grudiev, A; Wuensch, W

    2011-01-01T23:59:59.000Z

    A Damped Detuned Structure (DDS) for CLIC main linac has been proposed as an alternative to the present baseline design which is based on heavy damping. A first prototype, CLIC_DDS_A, for high power tests has been already designed and is under construction. It is also foreseen to design a further prototype, CLIC_DDS_B, to test both the wakefield suppression and high power performances. Wakefield calculations for DDS are, in the early design stage, based on single infinitely periodic cells. Though cell-to-cell interaction is taken into account to calculate the wakefields, it is important to study full structure properties using computational tools. In particular this is fundamental for defining the input parameters for the HOM coupler that is crucial for the performances of DDS. In the following a full analysis of wakefields and impedances based on simulations conducted with finite difference based electromagnetic computer code GdfidL will be presented.

  4. P. Muggli, ATF Users Meeting 07/05/07 Multi-bunch Plasma Wakefield

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Optronics, Inc., Bellevue, WA Presented by Patric Muggli, USC Work supported by US DoE 2 P. Muggli, ATF Users Meeting 070507 OUTLINE Introduction to the plasma wakefield...

  5. Particle-In-Cell Modeling of Plasma-Based Accelerators in Two and Three Dimensions

    E-Print Network [OSTI]

    Hemker, Roy G

    2015-01-01T23:59:59.000Z

    In this dissertation, a fully object-oriented, fully relativistic, multi-dimensional Particle-In-Cell code was developed and applied to answer key questions in plasma-based accelerator research. The simulations increase the understanding of the processes in laser plasma and beam-plasma interaction, allow for comparison with experiments, and motivate the development of theoretical models. The simulations support the idea that the injection of electrons in a plasma wave by using a transversely propagating laser pulse is possible. The beam parameters of the injected electrons found in the simulations compare reasonably with beams produced by conventional methods and therefore laser injection is an interesting concept for future plasma-based accelerators. Simulations of the optical guiding of a laser wakefield driver in a parabolic plasma channel support the idea that electrons can be accelerated over distances much longer than the Rayleigh length in a channel. Simulations of plasma wakefield acceleration in the ...

  6. High-gradient compact linear accelerator

    DOE Patents [OSTI]

    Carder, B.M.

    1998-05-26T23:59:59.000Z

    A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter. 10 figs.

  7. ALL OPTICAL ACCELERATOR EXPERIMENTS AT LBNL/ W.P. Leemans, D. Rodgers, P.E. Catravas, G. Fubiani, C.G.R. Geddes, E. Esarey, B.A.Shadwick,

    E-Print Network [OSTI]

    Wurtele, Jonathan

    ALL OPTICAL ACCELERATOR EXPERIMENTS AT LBNL/ W.P. Leemans, D. Rodgers, P.E. Catravas, G. Fubiani, C wakefield acceleration research at the l'OASIS laboratory of the Cen- ter for Beam Physics at LBNL]- [14]. In this article we describe experiments performed at the l'OASIS laboratory of LBNL [15

  8. Accelerator Research Department B Dept. of Applied Physics

    E-Print Network [OSTI]

    Wechsler, Risa H.

    1 Accelerator Research Department B Dept. of Applied Physics E163: Laser Acceleration at the NLCTA March 11, 2002 * Spokesman. #12;2 Accelerator Research Department B Dept. of Applied PhysicsTechnical Roadmap LEAPLEAP 1. Demonstrate the physics of laser acceleration in dielectric structures 2. Develop

  9. Beam-driven acceleration in ultra-dense plasma media

    SciTech Connect (OSTI)

    Shin, Young-Min [Fermi National Accelerator Laboratory, Batavia, IL (United States)

    2014-09-12T23:59:59.000Z

    Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 1025 m-3 and 1.6 x 1028 m-3 plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers 20 % higher acceleration gradient by enlarging the channel radius (r) from 0.2 Ap to 0.6 .Ap in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g. nanotubes) of high electron plasma density.

  10. Beam-driven acceleration in ultra-dense plasma media

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Shin, Young-Min [Fermi National Accelerator Laboratory, Batavia, IL (United States)

    2014-09-15T23:59:59.000Z

    Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 1025 m-3 and 1.6 x 1028 m-3 plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers 20 % higher acceleration gradient by enlarging the channel radius (r) from 0.2 ?p to 0.6 ?p in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g. nanotubes) of high electron plasma density.

  11. Beam-driven acceleration in ultra-dense plasma media

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Shin, Young-Min

    2014-09-15T23:59:59.000Z

    Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 1025 m-3 and 1.6 x 1028 m-3 plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers 20 % higher acceleration gradient by enlarging the channel radius (r)more »from 0.2 ?p to 0.6 ?p in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g. nanotubes) of high electron plasma density.« less

  12. Energy limitation of laser-plasma electron accelerators

    E-Print Network [OSTI]

    Cardenas, D E; Xu, J; Hofmann, L; Buck, A; Schmid, K; Sears, C M S; Rivas, D E; Shen, B; Veisz, L

    2015-01-01T23:59:59.000Z

    We report on systematic and high-precision measurements of dephasing, an effect that fundamentally limits the performance of laser wakefield accelerators. Utilizing shock-front injection, a technique providing stable, tunable and high-quality electron bunches, acceleration and deceleration of few-MeV quasi-monoenergetic beams were measured with sub-5-fs and 8-fs laser pulses. Typical density dependent electron energy evolution with 65-300 micrometers dephasing length and 6-20 MeV peak energy was observed and is well described with a simple model.

  13. HIGH GRADIENT INDUCTION ACCELERATOR

    SciTech Connect (OSTI)

    Caporaso, G J; Sampayan, S; Chen, Y; Blackfield, D; Harris, J; Hawkins, S; Holmes, C; Krogh, M; Nelson, S; Nunnally, W; Paul, A; Poole, B; Rhodes, M; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J

    2007-06-21T23:59:59.000Z

    A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase the average accelerating gradient by at least an order of magnitude over that of existing induction machines. The machine is based on the use of high gradient vacuum insulators, advanced dielectric materials and switches and is stimulated by the desire for compact flash x-ray radiography sources. Research describing an extreme variant of this technology aimed at proton therapy for cancer will be described. Progress in applying this technology to several applications will be reviewed.

  14. Resonant dielectric metamaterials

    DOE Patents [OSTI]

    Loui, Hung; Carroll, James; Clem, Paul G; Sinclair, Michael B

    2014-12-02T23:59:59.000Z

    A resonant dielectric metamaterial comprises a first and a second set of dielectric scattering particles (e.g., spheres) having different permittivities arranged in a cubic array. The array can be an ordered or randomized array of particles. The resonant dielectric metamaterials are low-loss 3D isotropic materials with negative permittivity and permeability. Such isotropic double negative materials offer polarization and direction independent electromagnetic wave propagation.

  15. Using Surface Impedance for Calculating Wakefields in Flat Geometry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bane, Karl; Stupakov, Gennady

    2015-03-01T23:59:59.000Z

    Beginning with Maxwell's equations and assuming only that the wall interaction can be approximated by a surface impedance, we derive formulas for the generalized longitudinal and transverse impedance in flat geometry, from which the wakefields can also be obtained. From the generalized impedances, by taking the proper limits, we obtain the normal longitudinal, dipole, and quad impedances in flat geometry. These equations can be applied to any surface impedance, such as the known dc, ac, and anomalous skin models of wall resistance, a model of wall roughness, or one for a pipe with small, periodic corrugations. We show that, formore »the particular case of dc wall resistance, the longitudinal impedance obtained here agrees with a known result in the literature, a result that was derived from a very general formula by Henke and Napoly. As concrete example, we apply our results to representative beam and machine parameters in the undulator region of LCLS-II and estimate the impact of the transverse wakes on the machine performance.« less

  16. Using Surface Impedance for Calculating Wakefields in Flat Geometry

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Bane, Karl; Stupakov, Gennady

    2015-03-01T23:59:59.000Z

    Beginning with Maxwell's equations and assuming only that the wall interaction can be approximated by a surface impedance, we derive formulas for the generalized longitudinal and transverse impedance in flat geometry, from which the wakefields can also be obtained. From the generalized impedances, by taking the proper limits, we obtain the normal longitudinal, dipole, and quad impedances in flat geometry. These equations can be applied to any surface impedance, such as the known dc, ac, and anomalous skin models of wall resistance, a model of wall roughness, or one for a pipe with small, periodic corrugations. We show that, for the particular case of dc wall resistance, the longitudinal impedance obtained here agrees with a known result in the literature, a result that was derived from a very general formula by Henke and Napoly. As concrete example, we apply our results to representative beam and machine parameters in the undulator region of LCLS-II and estimate the impact of the transverse wakes on the machine performance.

  17. Dielectric Theory of the Vacuum

    E-Print Network [OSTI]

    J. X. Zheng-Johansson

    2006-12-11T23:59:59.000Z

    The vacuum is proposed to be a dielectric medium constituted of neutral but polarizable vacuuons based on overall experimental observations in separate publications. In the present paper I formally develop the dielectric theory for this dielectric vacuum.

  18. EDITED--LS-332-DWA_FEL_August16

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    32 August 2012 A Compact Soft X-ray Free-Electron Laser Facility based on a Dielectric Wakefield Accelerator C. Jing, P. Schoessow, A. Kanareykin, Euclid Techlabs LLC, Solon, OH...

  19. Dielectric properties of aerogels

    SciTech Connect (OSTI)

    Hrubesh, L.W.; Keene, L.E.; Latorre, V.R. (Chemistry and Material Sciences Department, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States))

    1993-07-01T23:59:59.000Z

    We have measured the real (dielectric constant) and imaginary (loss factor) components of the complex relative permittivity at 298 [degree]K using microwave frequencies (2, 10, and 18--40 GHz), for bulk SiO[sub 2]-aerogels and for two types of organic aerogels, resorcinol-formaldehyde (RF) and melamine-formaldehyde (MF). Measured dielectric constants are found to vary linearly between values of 1.0 and 2.0 for aerogel densities from 10 to 500 kg/m[sup 3]. For the same range of densities, the measured loss tangents vary linearly between values of 2[times]10[sup [minus]4] and 7[times]10[sup [minus]2]. The observed linearity of the dielectric properties with density in aerogels at microwave frequencies shows that their dielectric behavior is more gas-like than solid-like. The dielectric properties of aerogels are shown to be significantly affected by the adsorbed water internal to the bulk material. For example, water accounts for 7% of the dielectric constant and 70% of the loss at microwave frequencies for silica aerogels. Because of their very high porosity, even with the water content, the aerogels are among the few materials exhibiting such low dielectric properties. Our measurements show that aerogels with greater than 99% porosity have dielectric constants less than 1.03; these are the lowest values ever reported for a bulk solid material.

  20. Application of High-performance Visual Analysis Methods to Laser Wakefield Particle Acceleration Data

    E-Print Network [OSTI]

    Rubel, Oliver

    2008-01-01T23:59:59.000Z

    index/query system for data extraction and subsetting. It implements the fastest-known bitmap compression

  1. Driving laser pulse evolution in a hollow channel laser wakefield accelerator

    E-Print Network [OSTI]

    Wurtele, Jonathan

    of different methods for laser accel- eration and summaries of experimental and theoretical progress can particle in the LWFA to about one Rayleigh range. Laser guiding in plasma channels has been proposed

  2. Laser-driven plasma-based accelerators: Wakefield excitation, channel guiding, and laser triggered particle injection*

    E-Print Network [OSTI]

    Wurtele, Jonathan

    particle injection* W. P. Leemans,,a) P. Volfbeyn, K. Z. Guo, and S. Chattopadhyay Ernest Orlando Lawrence-based injection of particles into a plasma wake, are presented. Details of the experimental program at Lawrence for the accel- erating fields as well as guiding for the laser, and a suitable laser driver. The most

  3. STABLE, MONOENERGETIC 50-400 MeV ELECTRON BEAMS WITH A MATCHED LASER WAKEFIELD ACCELERATOR

    E-Print Network [OSTI]

    Umstadter, Donald

    progress in laser-based particle accelera- tors [1]. Early breakthroughs in laser-based electron accel

  4. Multi-GeV Energy Gain in a Plasma-Wakefield Accelerator M. J. Hogan,1

    E-Print Network [OSTI]

    Jalali. Bahram

    m at the entrance of a 10 cm long column of lithium vapor with density 2:8 1017 atoms=cm3. The electron bunch fully ionizes the lithium vapor to create a plasma and then expels the plasma electrons-plasma interactions have demonstrated focusing gradients of MT=m [1] while laser plasma interactions have demonstrated

  5. Development of high gradient laser wakefield accelerators towards nuclear detection applications at LBNL

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    at LBNL Cameron G.R. Geddes1 , David L. Bruhwiler2 , John R. Cary2,3 , Eric H. Esarey1,4 , Anthony J Program, LBNL, 1 Cyclotron Rd MS 71-259, Berkeley CA 94720, United States 2 Tech-X Corp., 5621 Arapahoe experiments at LBNL demonstrated narrow energy spread beams, now with energies of up to 1 GeV in 3 cm using

  6. Undulator-Based Laser Wakefield Accelerator Electron Beam Energy Spread and Emittance Diagnostic

    E-Print Network [OSTI]

    Bakeman, M.S.

    2011-01-01T23:59:59.000Z

    ultra-short, high- peak-current, electron beams are ideal for driving a compact X U V free electron laser (

  7. THz radiation as a bunch diagnostic for laser-wakefield-accelerated electron bunches

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    the vacuum chamber by an ultra-intense laser pulse. A secondEO) crystal. An ultra-short NIR laser beam was used to probe

  8. Beam Matching to a Plasma Wakefield Accelerator Using a Ramped Density

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced Materials Find More Like This Return to Search BatterylessBeProfile

  9. Two GeV Electrons Achieved by Laser Plasma Wakefield Acceleration | U.S.

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin Transition in2,EHSS A-Zandof Energy Two CompaniesTwoTwoDOE

  10. Control of focusing forces and emittances in plasma-based accelerators using near-hollow plasma channels

    SciTech Connect (OSTI)

    Schroeder, Carl; Esarey, Eric; Benedetti, Carlo; Leemans, Wim

    2013-08-06T23:59:59.000Z

    A near-hollow plasma channel, where the plasma density in the channel is much less than the plasma density in the walls, is proposed to provide independent control over the focusing and accelerating forces in a plasma accelerator. In this geometry the low density in the channel contributes to the focusing forces, while the accelerating fields are determined by the high density in the channel walls. The channel also provides guiding for intense laser pulses used for wakefield excitation. Both electron and positron beams can be accelerated in a nearly symmetric fashion. Near-hollow plasma channels can effectively mitigate emittance growth due to Coulomb scattering for high energy physics applications.

  11. Wakefield induced Losses in the Manual Valves of the TESLA Cryomodule

    E-Print Network [OSTI]

    1 Wakefield induced Losses in the Manual Valves of the TESLA Cryomodule M.Dohlus,H.-P.Wedekind,K.Zapfe DeutschesElektronenSynchrotron Notkestr.85,D-22603Hamburg,Germany Abstract The beam pipe of the TESLA valves with spring type rf-shield which are presently used in the linac of the TESLA Test Facility

  12. LuaAV: Extensibility and Heterogeneity for Audiovisual Graham WAKEFIELD and Wesley SMITH and Charles ROBERTS

    E-Print Network [OSTI]

    California at Santa Barbara, University of

    LuaAV: Extensibility and Heterogeneity for Audiovisual Computing Graham WAKEFIELD and Wesley SMITH and Charles ROBERTS Media Arts and Technology, University of California Santa Barbara Santa Barbara, CA 93110 providing the flexibility and temporal accuracy demanded by interactive audio-visual media. Code generation

  13. Dielectric Actuation of Polymers

    E-Print Network [OSTI]

    Niu, Xiaofan

    2013-01-01T23:59:59.000Z

    strain in dielectric elastomers, Journal of Polymer SciencePart B: Polymer Physics. 49 (2011) 504–515. [25] X. Zhao, Z.Electroactive nanostructured polymers as tunable actuators,

  14. Production, Characterization, and Acceleration of Optical Microbunches

    SciTech Connect (OSTI)

    Sears, Christopher M.S.; /Stanford U. /SLAC

    2008-06-20T23:59:59.000Z

    Optical microbunches with a spacing of 800 nm have been produced for laser acceleration research. The microbunches are produced using a inverse Free-Electron-Laser (IFEL) followed by a dispersive chicane. The microbunched electron beam is characterized by coherent optical transition radiation (COTR) with good agreement to the analytic theory for bunch formation. In a second experiment the bunches are accelerated in a second stage to achieve for the first time direct net acceleration of electrons traveling in a vacuum with visible light. This dissertation presents the theory of microbunch formation and characterization of the microbunches. It also presents the design of the experimental hardware from magnetostatic and particle tracking simulations, to fabrication and measurement of the undulator and chicane magnets. Finally, the dissertation discusses three experiments aimed at demonstrating the IFEL interaction, microbunch production, and the net acceleration of the microbunched beam. At the close of the dissertation, a separate but related research effort on the tight focusing of electrons for coupling into optical scale, Photonic Bandgap, structures is presented. This includes the design and fabrication of a strong focusing permanent magnet quadrupole triplet and an outline of an initial experiment using the triplet to observe wakefields generated by an electron beam passing through an optical scale accelerator.

  15. Transformer ratio improvement for beam based plasma accelerators

    SciTech Connect (OSTI)

    O'Shea, Brendan; Rosenzweig, James; Barber, Samuel; Fukasawa, Atsushi; Williams, Oliver; Muggli, Patric; Yakimenko, Vitaly; Kusche, Karl [University of California, Los Angeles, Department of Physics and Astronomy, Los Angeles, CA 90095 (United States); University of Southern California, Department of Electrical Engineering, Los Angeles, CA 90089 U.S.A. and Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Muenchen (Germany); Accelerator Test Facility, Brookhaven National Lab, Upton, NY, 11973 (United States)

    2012-12-21T23:59:59.000Z

    Increasing the transformer ratio of wakefield accelerating systems improves the viability of present novel accelerating schemes. The use of asymmetric bunches to improve the transformer ratio of beam based plasma systems has been proposed for some time[1, 2] but suffered from lack appropriate beam creation systems. Recently these impediments have been overcome [3, 4] and the ability now exists to create bunches with current profiles shaped to overcome the symmetric beam limit of R {<=} 2. We present here work towards experiments designed to measure the transformer ratio of such beams, including theoretical models and simulations using VORPAL (a 3D capable PIC code) [5]. Specifically we discuss projects to be carried out in the quasi-nonlinear regime [6] at the UCLA Neptune Laboratory and the Accelerator Test Facility at Brookhaven National Lab.

  16. Self-guided wakefield experiments driven by petawatt class ultra-short laser pulses

    E-Print Network [OSTI]

    Mangles, S P D; Bellei, C; Dangor, A E; Kamperidis, C; Kneip, S; Nagel, S R; Willingale, L; Najmudin, Z

    2007-01-01T23:59:59.000Z

    We investigate the extension of self-injecting laser wakefield experiments to the regime that will be accessible with the next generation of petawatt class ultra-short pulse laser systems. Using linear scalings, current experimental trends and numerical simulations we determine the optimal laser and target parameters, i.e. focusing geometry, plasma density and target length, that are required to increase the electron beam energy (to > 1 GeV) without the use of external guiding structures.

  17. Thermally switchable dielectrics

    DOE Patents [OSTI]

    Dirk, Shawn M.; Johnson, Ross S.

    2013-04-30T23:59:59.000Z

    Precursor polymers to conjugated polymers, such as poly(phenylene vinylene), poly(poly(thiophene vinylene), poly(aniline vinylene), and poly(pyrrole vinylene), can be used as thermally switchable capacitor dielectrics that fail at a specific temperature due to the non-conjugated precursor polymer irreversibly switching from an insulator to the conjugated polymer, which serves as a bleed resistor. The precursor polymer is a good dielectric until it reaches a specific temperature determined by the stability of the leaving groups. Conjugation of the polymer backbone at high temperature effectively disables the capacitor, providing a `built-in` safety mechanism for electronic devices.

  18. Accelerators and the Accelerator Community

    E-Print Network [OSTI]

    Malamud, Ernest

    2009-01-01T23:59:59.000Z

    for a PhD in accelerator physics was by E.O. Lawrence.of Beams) organizes accelerator physics sessions at APSstudents specializing in accelerator physics are not being “

  19. Enhanced betatron X-rays from axially modulated plasma wakefields

    E-Print Network [OSTI]

    Palastro, J P; Gordon, D

    2015-01-01T23:59:59.000Z

    In the cavitation regime of plasma-based accelerators, a population of high-energy electrons tailing the driver can undergo betatron motion. The motion results in X-ray emission, but the brilliance and photon energy are limited by the electrons' initial transverse coordinate. To overcome this, we exploit parametrically unstable betatron motion in a cavitated, axially modulated plasma. Theory and simulations are presented showing that the unstable oscillations increase both the total X-ray energy and average photon energy.

  20. Photonic laser-driven accelerator for GALAXIE

    SciTech Connect (OSTI)

    Naranjo, B.; Ho, M.; Hoang, P.; Putterman, S.; Valloni, A.; Rosenzweig, J. B. [UCLA Dept. of Physics and Astronomy Los Angeles, CA 90095-1547 (United States)

    2012-12-21T23:59:59.000Z

    We report on the design and development of an all-dielectric laser-driven accelerator to be used in the GALAXIE (GV-per-meter Acce Lerator And X-ray-source Integrated Experiment) project's compact free-electron laser. The approach of our working design is to construct eigenmodes, borrowing from the field of photonics, which yield the appropriate, highly demanding dynamics in a high-field, short wavelength accelerator. Topics discussed include transverse focusing, power coupling, bunching, and fabrication.

  1. New Developments in the Simulation of Advanced Accelerator Concepts

    SciTech Connect (OSTI)

    Paul, K.; Cary, J.R.; Cowan, B.; Bruhwiler, D.L.; Geddes, C.G.R.; Mullowney, P.J.; Messmer, P.; Esarey, E.; Cormier-Michel, E.; Leemans, W.P.; Vay, J.-L.

    2008-09-10T23:59:59.000Z

    Improved computational methods are essential to the diverse and rapidly developing field of advanced accelerator concepts. We present an overview of some computational algorithms for laser-plasma concepts and high-brightness photocathode electron sources. In particular, we discuss algorithms for reduced laser-plasma models that can be orders of magnitude faster than their higher-fidelity counterparts, as well as important on-going efforts to include relevant additional physics that has been previously neglected. As an example of the former, we present 2D laser wakefield accelerator simulations in an optimal Lorentz frame, demonstrating>10 GeV energy gain of externally injected electrons over a 2 m interaction length, showing good agreement with predictions from scaled simulations and theory, with a speedup factor of ~;;2,000 as compared to standard particle-in-cell.

  2. Meter scale plasma source for plasma wakefield experiments

    SciTech Connect (OSTI)

    Vafaei-Najafabadi, N.; Shaw, J. L.; Marsh, K. A.; Joshi, C.; Hogan, M. J. [Department of Electrical Engineering, University of California Los Angeles, Los Angeles, CA 90095 (United States); SLAC National Accelerator Laboratory, Menlo Park, CA 94025 (United States)

    2012-12-21T23:59:59.000Z

    High accelerating gradients generated by a high density electron beam moving through plasma has been used to double the energy of the SLAC electron beam [1]. During that experiment, the electron current density was high enough to generate its own plasma without significant head erosion. In the newly commissioned FACET facility at SLAC, the peak current will be lower and without pre-ionization, head erosion will be a significant challenge for the planned experiments. In this work we report on our design of a meter scale plasma source for these experiments to effectively avoid the problem of head erosion. The plasma source is based on a homogeneous metal vapor gas column that is generated in a heat pipe oven [2]. A lithium oven over 30 cm long at densities over 10{sup 17} cm{sup -3} has been constructed and tested at UCLA. The plasma is then generated by coupling a 10 TW short pulse Ti:Sapphire laser into the gas column using an axicon lens setup. The Bessel profile of the axicon setup creates a region of high intensity that can stretch over the full length of the gas column with approximately constant diameter. In this region of high intensity, the alkali metal vapor is ionized through multi-photon ionization process. In this manner, a fully ionized meter scale plasma of uniform density can be formed. Methods for controlling the plasma diameter and length will also be discussed.

  3. Tomorrow's cities -the lamp-posts watching every move1 by Jane Wakefield for BBC News2

    E-Print Network [OSTI]

    South Bohemia, University of

    the city council is looking to upgrade its23 streetlights to more energy-efficient LED lights - likely in the area. The pilot project will be integrated with the newly built City Operations Centre, where CCTVTomorrow's cities - the lamp-posts watching every move1 by Jane Wakefield for BBC News2 3 Imagine

  4. Beam-driven acceleration in ultra-dense plasma media

    SciTech Connect (OSTI)

    Shin, Young-Min [Fermi National Accelerator Laboratory, Batavia, IL (United States)

    2014-09-15T23:59:59.000Z

    Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 1025 m-3 and 1.6 x 1028 m-3 plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers 20 % higher acceleration gradient by enlarging the channel radius (r) from 0.2 ?p to 0.6 ?p in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g. nanotubes) of high electron plasma density.

  5. Beam-driven acceleration in ultra-dense plasma media

    SciTech Connect (OSTI)

    Shin, Young-Min [Department of Physics, Northern Illinois University, Dekalb, Illinois 60115 (United States); Accelerator Physics Center (APC), Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510 (United States)

    2014-09-15T23:59:59.000Z

    Accelerating parameters of beam-driven wakefield acceleration in an extremely dense plasma column has been analyzed with the dynamic framed particle-in-cell plasma simulator, and compared with analytic calculations. In the model, a witness beam undergoes a TeV/m scale alternating potential gradient excited by a micro-bunched drive beam in a 10{sup 25?}m{sup ?3} and 1.6?×?10{sup 28?}m{sup ?3} plasma column. The acceleration gradient, energy gain, and transformer ratio have been extensively studied in quasi-linear, linear-, and blowout-regimes. The simulation analysis indicated that in the beam-driven acceleration system a hollow plasma channel offers ?20% higher acceleration gradient by enlarging the channel radius (r) from 0.2 ?{sub p} to 0.6 ?{sub p} in a blowout regime. This paper suggests a feasibility of TeV/m scale acceleration with a hollow crystalline structure (e.g., nanotubes) of high electron plasma density.

  6. Photonic Crystal Laser-Driven Accelerator Structures

    SciTech Connect (OSTI)

    Cowan, Benjamin M.

    2007-08-22T23:59:59.000Z

    Laser-driven acceleration holds great promise for significantly improving accelerating gradient. However, scaling the conventional process of structure-based acceleration in vacuum down to optical wavelengths requires a substantially different kind of structure. We require an optical waveguide that (1) is constructed out of dielectric materials, (2) has transverse size on the order of a wavelength, and (3) supports a mode with speed-of-light phase velocity in vacuum. Photonic crystals---structures whose electromagnetic properties are spatially periodic---can meet these requirements. We discuss simulated photonic crystal accelerator structures and describe their properties. We begin with a class of two-dimensional structures which serves to illustrate the design considerations and trade-offs involved. We then present a three-dimensional structure, and describe its performance in terms of accelerating gradient and efficiency. We discuss particle beam dynamics in this structure, demonstrating a method for keeping a beam confined to the waveguide. We also discuss material and fabrication considerations. Since accelerating gradient is limited by optical damage to the structure, the damage threshold of the dielectric is a critical parameter. We experimentally measure the damage threshold of silicon for picosecond pulses in the infrared, and determine that our structure is capable of sustaining an accelerating gradient of 300 MV/m at 1550 nm. Finally, we discuss possibilities for manufacturing these structures using common microfabrication techniques.

  7. Tuning the electron energy by controlling the density perturbation position in laser plasma accelerators

    SciTech Connect (OSTI)

    Brijesh, P.; Thaury, C.; Phuoc, K. T.; Corde, S.; Lambert, G.; Malka, V. [Laboratoire d'Optique Appliquee, ENSTA ParisTech, CNRS UMR7639, Ecole Polytechnique, 91761 Palaiseau (France); Mangles, S. P. D.; Bloom, M.; Kneip, S. [Blackett Laboratory, Imperial College, London SW7 2AZ (United Kingdom)

    2012-06-15T23:59:59.000Z

    A density perturbation in an underdense plasma was used to improve the quality of electron bunches produced in the laser-plasma wakefield acceleration scheme. Quasi-monoenergetic electrons were generated by controlled injection in the longitudinal density gradients of the density perturbation. By tuning the position of the density perturbation along the laser propagation axis, a fine control of the electron energy from a mean value of 60 MeV to 120 MeV has been demonstrated with a relative energy-spread of 15 {+-} 3.6%, divergence of 4 {+-} 0.8 mrad, and charge of 6 {+-} 1.8 pC.

  8. Dielectric microscopy with submillimeter resolution

    E-Print Network [OSTI]

    Nathan S. Greeney; John A. Scales

    2007-06-20T23:59:59.000Z

    In analogy with optical near-field scanning methods, we use tapered dielectric waveguides as probes for a millimeter wave vector network analyzer. By scanning thin samples between two such probes we are able to map the spatially varying dielectric properties of materials with sub-wavelength resolution; using a 150 GHz probe in transmision mode we see spatial resolution of around 500 microns. We have applied this method to a variety of highly heterogeneous materials. Here we show dielectric maps of granite and oil shale.

  9. Towards all-dielectric metamaterials and nanophotonics

    E-Print Network [OSTI]

    Krasnok, Alexander; Petrov, Mikhail; Savelev, Roman; Belov, Pavel; Kivshar, Yuri

    2015-01-01T23:59:59.000Z

    We review a new, rapidly developing field of all-dielectric nanophotonics which allows to control both magnetic and electric response of structured matter by engineering the Mie resonances in high-index dielectric nanoparticles. We discuss optical properties of such dielectric nanoparticles, methods of their fabrication, and also recent advances in all-dielectric metadevices including couple-resonator dielectric waveguides, nanoantennas, and metasurfaces.

  10. Accelerate Energy

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Accelerate Energy Productivity 2030 Over the next year, the U.S. Department of Energy, the Council on Competitiveness and the Alliance to Save Energy will join forces to undertake...

  11. COMPACT ACCELERATOR CONCEPT FOR PROTON THERAPY

    SciTech Connect (OSTI)

    Caporaso, G; Sampayan, S; Chen, Y; Harris, J; Hawkins, S; Holmes, C; Krogh, M; Nelson, S; Nunnally, W; Paul, A; Poole, B; Rhodes, M; Sanders, D; Selenes, K; Sullivan, J; Wang, L; Watson, J

    2006-08-18T23:59:59.000Z

    A new type of compact induction accelerator is under development at the Lawrence Livermore National Laboratory that promises to increase the average accelerating gradient by at least an order of magnitude over that of existing induction machines. The machine is based on the use of high gradient vacuum insulators, advanced dielectric materials and switches and is being developed as a compact flash x-ray radiography source. Research describing an extreme variant of this technology aimed at proton therapy for cancer will be presented.

  12. Acceleration Fund

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041cloth DocumentationProducts (VAP) VAP7-0973 1 Introduction In theACME - AcceleratedAccelerating

  13. Dielectric Elastomers for Actuation and Energy Harvesting

    E-Print Network [OSTI]

    Brochu, Paul

    2012-01-01T23:59:59.000Z

    152 10 Acrylic Interpenetrating Polymer Network DielectricSilicone Interpenetrating Polymer Network Elastomers withbased on interpenetrating polymer networks. Proceedings of

  14. Plasma accelerator

    DOE Patents [OSTI]

    Wang, Zhehui (Los Alamos, NM); Barnes, Cris W. (Santa Fe, NM)

    2002-01-01T23:59:59.000Z

    There has been invented an apparatus for acceleration of a plasma having coaxially positioned, constant diameter, cylindrical electrodes which are modified to converge (for a positive polarity inner electrode and a negatively charged outer electrode) at the plasma output end of the annulus between the electrodes to achieve improved particle flux per unit of power.

  15. COLLIDING PULSE INJECTION EXPERIMENTS IN NON-COLLINEAR GEOMETRY FOR CONTROLLED LASER PLASMA WAKEFIELD

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    emittance) is important for future plasma based accelerators and for applications. In any particle accelerator, particle injection into the accelerating structure is a key technology. In all cur- rent laser with acceler- Work supported by DOE grant DE-AC02-05CH11231, DARPA, and INCITE computational grant. CToth

  16. Electron depletion via cathode spot dispersion of dielectric powder into an overhead plasma

    SciTech Connect (OSTI)

    Gillman, Eric D. [Naval Research Laboratory, 4555 Overlook Ave SW, Washington, District of Columbia 20375 (United States)] [Naval Research Laboratory, 4555 Overlook Ave SW, Washington, District of Columbia 20375 (United States); Foster, John E. [Department of Nuclear Engineering and Radiological Sciences (NERS), University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, Michigan 48109 (United States)] [Department of Nuclear Engineering and Radiological Sciences (NERS), University of Michigan, 2355 Bonisteel Blvd., Ann Arbor, Michigan 48109 (United States)

    2013-11-15T23:59:59.000Z

    The effectiveness of cathode spot delivered dielectric particles for the purpose of plasma depletion is investigated. Here, cathode spot flows kinetically entrain and accelerate dielectric particles originally at rest into a background plasma. The time variation of the background plasma density is tracked using a cylindrical Langmuir probe biased approximately at electron saturation. As inferred from changes in the electron saturation current, depletion fractions of up to 95% are observed. This method could be exploited as a means of communications blackout mitigation for manned and unmanned reentering spacecraft as well as any high speed vehicle enveloped by a dense plasma layer.

  17. Effect of the laser wavefront in a laser-plasma accelerator

    E-Print Network [OSTI]

    Beaurepaire, B; Bocoum, M; Böhle, F; Jullien, A; Rousseau, J-P; Lefrou, T; Douillet, D; Iaquaniello, G; Lopez-Martens, R; Lifschitz, A; Faure, J

    2015-01-01T23:59:59.000Z

    A high repetition rate electron source was generated by tightly focusing kHz, few-mJ laser pulses into an underdense plasma. This high intensity laser-plasma interaction led to stable electron beams over several hours but with strikingly complex transverse distributions even for good quality laser focal spots. Analysis of the experimental data, along with results of PIC simulations demonstrate the role of the laser wavefront on the acceleration of electrons. Distortions of the laser wavefront cause spatial inhomogeneities in the out-of-focus laser distribution and consequently, the laser pulse drives an inhomogenous transverse wakefield whose focusing/defocusing properties affect the electron distribution. These findings explain the experimental results and suggest the possibility of controlling the electron spatial distribution in laser-plasma accelerators by tailoring the laser wavefront.

  18. Some wakefield effects in the superconducting RF cavities of LCLS-II

    E-Print Network [OSTI]

    Bane, K; Yakovlev, V

    2014-01-01T23:59:59.000Z

    For LCLS-II we estimate the power of radiated wakefields generated in the SRF cavities (including the 3rd harmonic cavities) and in the end transitions. Much of this power will pass through and reflect in the strings of cryomodules that comprise linacs L1, L2, or L3. Presumably, some of it will be absorbed by the higher order mode (HOM) couplers, or by the absorbers at warmer temperatures situated between the cryomodules. We investigate where such power gets generated, but not where it ends up. As such the results can serve as a pessimistic calculation of the extra power that needs to be removed by the cryosystem. Finally, we also estimate---under the assumption that all the wake power ends up in the SRF walls---the wall heating and the extent of Cooper pair breaking in L3, where the bunch is most intense. Note that all calculations here are of single bunch effects; thus resonant interactions are not included.

  19. Engineering Design of a Multipurpose X-band Accelerating Structure

    E-Print Network [OSTI]

    Gudkov, Dmitry; Samoshkin, Alexander; Zennaro, Riccardo; Dehler, Micha; Raguin, Jean-Yves

    2010-01-01T23:59:59.000Z

    Both FEL projects, SwissFEL and Fermi-Elettra each require an X-band RF accelerating structure for optimal bunch compression at the respective injectors. As the CLIC project is pursuing a program for producing and testing the X-band high-gradient RF structures, a collaboration between PSI, Elettra and CERN has been established to build a multipurpose X-band accelerating structure. This paper focuses on its engineering design, which is based on the disked cells jointed together by diffusion bonding. Vacuum brazing and laser beam welding is used for auxiliary components. The accelerating structure consists of two coupler subassemblies, 73 disks and includes a wakefield monitor and diagnostic waveguides. The engineering study includes the external cooling system, consisting of two parallel cooling circuits and an RF tuning system, which allows phase advance tuning of the cell by deforming the outer wall. The engineering solution for the installation and sealing of the wake field monitor feed-through devices that...

  20. MUON ACCELERATION

    SciTech Connect (OSTI)

    BERG,S.J.

    2003-11-18T23:59:59.000Z

    One of the major motivations driving recent interest in FFAGs is their use for the cost-effective acceleration of muons. This paper summarizes the progress in this area that was achieved leading up to and at the FFAG workshop at KEK from July 7-12, 2003. Much of the relevant background and references are also given here, to give a context to the progress we have made.

  1. Analysis Code for High Gradient Dielectric Insulator Surface Breakdown

    SciTech Connect (OSTI)

    Ives, Robert Lawrence [Calabazas Creek Research, Inc.; Verboncoeur, John [University of California - Berkeley; Aldan, Manuel [University of California, Berkeley

    2010-05-30T23:59:59.000Z

    High voltage (HV) insulators are critical components in high-energy, accelerator and pulsed power systems that drive diverse applications in the national security, nuclear weapons science, defense and industrial arenas. In these systems, the insulator may separate vacuum/non-vacuum regions or conductors with high electrical field gradients. These insulators will often fail at electric fields over an order of magnitude lower than their intrinsic dielectric strength due to flashover at the dielectric interface. Decades of studies have produced a wealth of information on fundamental processes and mechanisms important for flashover initiation, but only for relatively simple insulator configurations in controlled environments. Accelerator and pulsed power system designers are faced with applying the fundamental knowledge to complex, operational devices with escalating HV requirements. Designers are forced to rely on “best practices” and expensive prototype testing, providing boundaries for successful operation. However, the safety margin is difficult to estimate, and system design must be very conservative for situations where testing is not practicable, or replacement of failed parts is disruptive or expensive. The Phase I program demonstrated the feasibility of developing an advanced code for modeling insulator breakdown. Such a code would be of great interest for a number of applications, including high energy physics, microwave source development, fusion sciences, and other research and industrial applications using high voltage devices.

  2. Accelerators and the Accelerator Community

    SciTech Connect (OSTI)

    Malamud, Ernest; Sessler, Andrew

    2008-06-01T23:59:59.000Z

    In this paper, standing back--looking from afar--and adopting a historical perspective, the field of accelerator science is examined. How it grew, what are the forces that made it what it is, where it is now, and what it is likely to be in the future are the subjects explored. Clearly, a great deal of personal opinion is invoked in this process.

  3. Optimization of the Combined Proton Acceleration Regime with a Target Composition Scheme

    E-Print Network [OSTI]

    Yao, W P; Zheng, C Y; Liu, Z J; Yan, X Q

    2015-01-01T23:59:59.000Z

    A target composition scheme to optimize the combined proton acceleration regime is presented and verified by two-dimensional particle-in-cell (2D PIC) simulations by using an ultra-intense circularly-polarized (CP) laser pulse irradiating an overdense hydrocarbon (CH) target, instead of a pure hydrogen (H) one. The combined acceleration regime is a two-stage proton acceleration scheme combining the radiation pressure dominated acceleration (RPDA) stage and the laser wakefield acceleration (LWFA) stage sequentially together. With an ultra-intense CP laser pulse irradiating an overdense CH target, followed by an underdense tritium plasma gas, protons with higher energies (from about $20$ GeV up to about $30$ GeV) and lower energy spreads (from about $18\\%$ down to about $5\\%$ in full-width at half-maximum, or FWHM) are generated, as compared to the use of a pure H target. It is because protons can be more stably pre-accelerated in the first RPDA stage when using CH targets. With the increase of the carbon-to-hy...

  4. Peculiar acceleration

    E-Print Network [OSTI]

    Luca Amendola; Claudia Quercellini; Amedeo Balbi

    2007-08-08T23:59:59.000Z

    It has been proposed recently to observe the change in cosmological redshift of distant galaxies or quasars with the next generation of large telescope and ultra-stable spectrographs (the so-called Sandage-Loeb test). Here we investigate the possibility of observing the change in peculiar velocity in nearby clusters and galaxies. This ``peculiar acceleration'' could help reconstructing the gravitational potential without assuming virialization. We show that the expected effect is of the same order of magnitude of the cosmological velocity shift. Finally, we discuss how to convert the theoretical predictions into quantities directly related to observations.

  5. ACCELERATE ENERGY

    Broader source: Energy.gov (indexed) [DOE]

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742Energy China 2015ofDepartmentDepartment of Energy ThisThistheSummaryACCELERATE ENERGY

  6. Linear Accelerator

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is Your HomeLatestCenter (LMI-EFRC) -Choices toLeeLinear Accelerator

  7. End moldings for cable dielectrics

    DOE Patents [OSTI]

    Roose, Lars D. (Albuquerque, NM)

    2000-01-01T23:59:59.000Z

    End moldings for high-voltage cables are described wherein the dielectric insulator of the cable is heated and molded to conform to a desired shape. As a consequence, high quality substantially bubble-free cable connectors suitable for mating to premanufactured fittings are made. Disclosed is a method for making the cable connectors either in the field or in a factory, molds suitable for use with the method, and the molded cable connectors, themselves.

  8. Electromechanics of dielectric particles in dielectric liquids acted on by a microelectrode array 

    E-Print Network [OSTI]

    Seo, Cheong Soo

    2006-04-12T23:59:59.000Z

    Arrays of microelectrodes were used to apply forces to dielectric (soda lime glass) spheres in a thin (200 micrometer thick) layer of a dielectric liquid polymer (EOPN 8021). The microelectrodes were fabricated using standard photolithographic...

  9. PNL-SA-22914 Presented at the 48th Meeting of the Mechanical Failures Prevention Group (MFPG 48) 19-21 April 1994 in Wakefield, MA

    E-Print Network [OSTI]

    -21 April 1994 in Wakefield, MA AN ARTIFICIAL NEURAL NETWORK SYSTEM FOR DIAGNOSING GAS TURBINE ENGINE FUEL until it produces an accurate diagnosis. For example, troubleshooting the AGT-1500 gas turbine engine Laboratory are developing a turbine engine diagnostic system for the M1A1 Abrams tank. This system employs

  10. Energy-momentum balance in quantum dielectrics

    E-Print Network [OSTI]

    Ulf Leonhardt

    2005-12-21T23:59:59.000Z

    We calculate the energy-momentum balance in quantum dielectrics such as Bose-Einstein condensates. In agreement with the experiment [G. K. Campbell et al. Phys. Rev. Lett. 94, 170403 (2005)] variations of the Minkowski momentum are imprinted onto the phase, whereas the Abraham tensor drives the flow of the dielectric. Our analysis indicates that the Abraham-Minkowski controversy has its root in the Roentgen interaction of the electromagnetic field in dielectric media.

  11. Casimir energy and dilute dielectric ball

    E-Print Network [OSTI]

    Valery N. Marachevsky

    2000-10-24T23:59:59.000Z

    General formalism of quantum field theory and addition theorem for Bessel functions are applied to derive formula for Casimir-Polder energy of interaction between a polarizable particle and a dilute dielectric ball. The equivalence of dipole-dipole interaction and Casimir energy for dilute homogeneous dielectrics is shown. A novel method is used to derive Casimir energy of a dilute dielectric ball without divergences in calculations. Physically realistic model of a dilute ball is discussed. Different approaches to the calculation of Casimir energy of a dielectric ball are reviewed.

  12. Mechanical constraints enhance electrical energy densities of soft dielectrics

    E-Print Network [OSTI]

    Ferrari, Silvia

    Mechanical constraints enhance electrical energy densities of soft dielectrics Lin Zhang, Qiming, the dielectric will breakdown electrically. The breakdown limits the electrical energy density of the dielectric electric fields and thus increase their electrical energy densities. The mechanical constraints suppress

  13. Dielectric strength of parylene HT

    SciTech Connect (OSTI)

    Diaham, S., E-mail: sombel.diaham@laplace.univ-tlse.fr; Bechara, M.; Locatelli, M.-L.; Khazaka, R. [Université de Toulouse, UPS, INPT, LAPLACE, 118 route de Narbonne-Bât. 3R3, F-31062 Toulouse Cedex 9 (France); CNRS, LAPLACE, F-31062 Toulouse (France); Tenailleau, C. [Université de Toulouse, UPS, Laboratoire CIRIMAT/LCMIE, 118 route de Narbonne-Bât. 2R1, F-31062 Toulouse Cedex 9 (France); Kumar, R. [Speciality Coating Systems, Inc. (SCS), Cookson Electronics, 7645 Woodland Drive, Indianapolis, Indiana 46278 (United States)

    2014-02-07T23:59:59.000Z

    The dielectric strength of parylene HT (PA-HT) films was studied at room temperature in a wide thickness range from 500?nm to 50??m and was correlated with nano- and microstructure analyses. X-ray diffraction and polarized optical microscopy have revealed an enhancement of crystallization and spherulites development, respectively, with increasing the material thickness (d). Moreover, a critical thickness d{sub C} (between 5 and 10??m) is identified corresponding to the beginning of spherulite developments in the films. Two distinct behaviors of the dielectric strength (F{sub B}) appear in the thickness range. For d???d{sub C}, PA-HT films exhibit a decrease in the breakdown field following a negative slope (F{sub B}???d{sup ?0.4}), while for d?dielectric strength (F{sub B}???10 MV/cm) is obtained. A model of spherulite development in PA-HT films with increasing the thickness is proposed. The decrease in F{sub B} above d{sub C} is explained by the spherulites development, whereas its increase below d{sub C} is induced by the crystallites growth. An annealing of the material shows both an enhancement of F{sub B} and an increase of the crystallites and spherulites dimensions, whatever the thickness. The breakdown field becomes thickness-independent below d{sub C} showing a strong influence of the nano-scale structural parameters. On the contrary, both nano- and micro-scale structural parameters appear as influent on F{sub B} for d???d{sub C}.

  14. Dielectric liquid ionization chambers for detecting fast neutrons

    E-Print Network [OSTI]

    Boyd, Erin M

    2008-01-01T23:59:59.000Z

    Three ionization chambers with different geometries have been constructed and filled with dielectric liquids for detection of fast neutrons. The three dielectric liquids studied were Tetramethylsilane (TMS), Tetramethylpentane ...

  15. High Dielectric Constant Capacitors for Power Electronic Systems...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Dielectric Constant Capacitors for Power Electronic Systems High Dielectric Constant Capacitors for Power Electronic Systems 2009 DOE Hydrogen Program and Vehicle Technologies...

  16. High Temperature Thin Film Polymer Dielectric Based Capacitors...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    High Temperature Thin Film Polymer Dielectric Based Capacitors for HEV Power Electronic Systems High Temperature Thin Film Polymer Dielectric Based Capacitors for HEV Power...

  17. High thermal conductivity lossy dielectric using a multi layer configuration

    DOE Patents [OSTI]

    Tiegs, Terry N. (Lenoir City, TN); Kiggans, Jr., James O. (Oak Ridge, TN)

    2003-01-01T23:59:59.000Z

    Systems and methods are described for loss dielectrics. A loss dielectric includes at least one high dielectric loss layer and at least one high thermal conductivity-electrically insulating layer adjacent the at least one high dielectric loss layer. A method of manufacturing a loss dielectric includes providing at least one high dielectric loss layer and providing at least one high thermal conductivity-electrically insulating layer adjacent the at least one high dielectric loss layer. The systems and methods provide advantages because the loss dielectrics are less costly and more environmentally friendly than the available alternatives.

  18. for sequence accelerators

    E-Print Network [OSTI]

    Zakharov, Vladimir

    Wynn's -algorithm for sequence accelerators using high precision arithmetic Rachel Baumann University of Arizona Wynn's -algorithm for sequence accelerators using high precision arithmetic Rachel Baumann University of Arizona April 17, 2012 #12;Wynn's -algorithm for sequence accelerators using high

  19. Laser wakefield simulation using a speed-of-light frame envelope model

    E-Print Network [OSTI]

    Cowan, B.

    2010-01-01T23:59:59.000Z

    Laser wake?eld simulation using a speed-of-light frameAbstract. Simulation of laser wake?eld accelerator (LWFA)extend hundreds of laser wave- lengths transversely and many

  20. Dielectric properties and electronic applications of aerogels

    SciTech Connect (OSTI)

    Hrubesh, L.W.; Pekala, R.W.

    1993-07-01T23:59:59.000Z

    Among their other exceptional properties, aerogels also exhibits unusual dielectric properties due to their nano-sized structures and high porosities. For example, our measurements of the dielectric constants and loss tangents for several aerogel varieties at microwave frequencies show that they both vary linearly with the aerogel density, indicating that the dielectric behavior of aerogels is more gas-like than solid-like. We have also measured the dielectric strength of silica aerogels and find that they are better than ceramics for high voltage insulation. The low dielectric constants and loss tangents of aerogels, along with their controllable thermal expansion properties, make them desirable materials for use as thin films in high speed integrated digital and microwave circuitry.

  1. Multiorbit induction accelerators

    SciTech Connect (OSTI)

    Zvontsov, A.A.; Kas'yanov, V.A.; Chakhlov, V.L.

    1985-09-01T23:59:59.000Z

    Large numbers of particles accelerated per cycle are made possible by accelerating simultaneously in several equilibrium orbits in a single betatron structure. (AIP)

  2. ACCELERATOR TEST FACILITY

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    LABORATORY PHYSICS DEPARTMENT Effective: 04012004 Page 1 of 2 Subject: Accelerator Test Facility - Linear Accelerator General Systems Guide Prepared by: Michael Zarcone...

  3. New initiatives for producing high current electron accelerators

    SciTech Connect (OSTI)

    Faehl, R.J.; Keinigs, R.K.; Pogue, E.W.

    1996-11-01T23:59:59.000Z

    New classes of compact electron accelerators able to deliver multi-kiloamperes of pulsed 10-50 MeV electron beams are being studied. One class is based upon rf linac technology with dielectric-filled cavities. For materials with {epsilon}/{epsilon}{sub o}>>1, the greatly increased energy storage permits high current operation. The second type is a high energy injected betatron. Circulating current limits scale as {Beta}{sup 2}{gamma}{sup 3}.

  4. Plasma density from Cerenkov radiation, betatron oscillations, and beam steering in a plasma wakefield experiment at 30 GeV

    SciTech Connect (OSTI)

    Catravas, P.; Chattopadhyay, S.; Esarey, E.; Leemans, W.P.; Assmann, R.; Decker, F.-J.; Hogan, M.J.; Iverson, R.; Siemann, R.H.; Walz, D.; Whittum, D.; Blue, B.; Clayton, C.; Joshi, C.; Marsh, K.; Mori, W.B.; Wang, S.; Katsouleas, T.; Lee, S.; Muggli, P.

    2001-01-01T23:59:59.000Z

    A method for using Cerenkov radiation near atomic spectral lines to measure plasma source properties for plasma wakefield applications has been discussed and experimentally verified. Because the radiation co-propagates with the electron beam, the radiation samples the source properties exactly along the path of interest with perfect temporal synchronization. Observation wavelengths were chosen with respect to the atomic resonances of the plasma source, where the relative change in the index of refraction strongly affects the Cerenkov cone angle, and permits flexible diagnostic design. The Cerenkov spatial profiles were systematically studied for a Lithium heat pipe oven as a function of oven temperature and observation wavelength. Neutral densities and plasma densities were extracted from the measurements.

  5. Method of and apparatus for accelerating a projectile

    DOE Patents [OSTI]

    Goldstein, Yeshayahu S. A. (Gaithersburg, MD); Tidman, Derek A. (Silver Spring, MD)

    1986-01-01T23:59:59.000Z

    A projectile is accelerated along a confined path by supplying a pulsed high pressure, high velocity plasma jet to the rear of the projectile as the projectile traverses the path. The jet enters the confined path at a non-zero angle relative to the projectile path. The pulse is derived from a dielectric capillary tube having an interior wall from which plasma forming material is ablated in response to a discharge voltage. The projectile can be accelerated in response to the kinetic energy in the plasma jet or in response to a pressure increase of gases in the confined path resulting from the heat added to the gases by the plasma.

  6. SLAC National Accelerator Laboratory Accelerator Physics Faculty Search

    E-Print Network [OSTI]

    Ford, James

    SLAC National Accelerator Laboratory Accelerator Physics Faculty Search The SLAC National Accelerator Laboratory invites applications for a faculty appointment in Accelerator Physics (LCLS), LCLS-II, SPEAR-3, NLC Test Accelerator (NLCTA), Cathode Test Facility (CTF), the proposed

  7. Superconducting Radiofrequency (SRF) Accelerator Cavities

    ScienceCinema (OSTI)

    Reece, Charlie

    2014-05-22T23:59:59.000Z

    Charlie Reece, an accelerator technology scientist, explains how superconducting radiofrequency accelerator cavities work.

  8. Facility for Advanced Accelerator Experimental Tests at SLAC (FACET) Conceptual Design Report

    SciTech Connect (OSTI)

    Amann, J.; Bane, K.; /SLAC

    2009-10-30T23:59:59.000Z

    This Conceptual Design Report (CDR) describes the design of FACET. It will be updated to stay current with the developing design of the facility. This CDR begins as the baseline conceptual design and will evolve into an 'as-built' manual for the completed facility. The Executive Summary, Chapter 1, gives an introduction to the FACET project and describes the salient features of its design. Chapter 2 gives an overview of FACET. It describes the general parameters of the machine and the basic approaches to implementation. The FACET project does not include the implementation of specific scientific experiments either for plasma wake-field acceleration for other applications. Nonetheless, enough work has been done to define potential experiments to assure that the facility can meet the requirements of the experimental community. Chapter 3, Scientific Case, describes the planned plasma wakefield and other experiments. Chapter 4, Technical Description of FACET, describes the parameters and design of all technical systems of FACET. FACET uses the first two thirds of the existing SLAC linac to accelerate the beam to about 20GeV, and compress it with the aid of two chicanes, located in Sector 10 and Sector 20. The Sector 20 area will include a focusing system, the generic experimental area and the beam dump. Chapter 5, Management of Scientific Program, describes the management of the scientific program at FACET. Chapter 6, Environment, Safety and Health and Quality Assurance, describes the existing programs at SLAC and their application to the FACET project. It includes a preliminary analysis of safety hazards and the planned mitigation. Chapter 7, Work Breakdown Structure, describes the structure used for developing the cost estimates, which will also be used to manage the project. The chapter defines the scope of work of each element down to level 3.

  9. Layered Binary-Dielectrics for Energy Applications: Limitations and Potentials

    SciTech Connect (OSTI)

    Tuncer, Enis [ORNL

    2012-01-01T23:59:59.000Z

    In this Letter, an attempt is made to illustrate how performance of an electrically insulating material, a dielectric, can be improved by constructing a layered binary-dielectric structure that employs a weak insulator with high dielectric permittivity. It is shown that layered binary-dielectrics could have a signicant impact on energy storage and electrical insulation.

  10. Controlled Electron Injection into Plasma Accelerators and SpaceCharge Estimates

    SciTech Connect (OSTI)

    Fubiani, Gwenael J.

    2005-09-01T23:59:59.000Z

    Plasma based accelerators are capable of producing electron sources which are ultra-compact (a few microns) and high energies (up to hundreds of MeVs) in much shorter distances than conventional accelerators. This is due to the large longitudinal electric field that can be excited without the limitation of breakdown as in RF structures.The characteristic scale length of the accelerating field is the plasma wavelength and for typical densities ranging from 1018 - 1019 cm-3, the accelerating fields and scale length can hence be on the order of 10-100GV/m and 10-40 mu m, respectively. The production of quasimonoenergetic beams was recently obtained in a regime relying on self-trapping of background plasma electrons, using a single laser pulse for wakefield generation. In this dissertation, we study the controlled injection via the beating of two lasers (the pump laser pulse creating the plasma wave and a second beam being propagated in opposite direction) which induce a localized injection of background plasma electrons. The aim of this dissertation is to describe in detail the physics of optical injection using two lasers, the characteristics of the electron beams produced (the micrometer scale plasma wavelength can result in femtosecond and even attosecond bunches) as well as a concise estimate of the effects of space charge on the dynamics of an ultra-dense electron bunch with a large energy spread.

  11. Epoxy Foam Encapsulants: Processing and Dielectric Characterization

    SciTech Connect (OSTI)

    Linda Domeier; Marion Hunter

    1999-01-01T23:59:59.000Z

    The dielectric performance of epoxy foams was investigated to determine if such materials might provide advantages over more standard polyurethane foams in the encapsulation of electronic assemblies. Comparisons of the dielectric characteristics of epoxy and urethane encapsulant foams found no significant differences between the two resin types and no significant difference between as-molded and machined foams. This study specifically evaluated the formulation and processing of epoxy foams using simple methylhydrosiloxanes as the flowing agent and compared the dielectric performance of those to urethane foams of similar density.

  12. K. Baird, F.-J. Decker, M. J. Hogan* , R.H. Iverson, P. Raimondi, R.H. Siemann, D. Walz

    E-Print Network [OSTI]

    a unique and timely opportunity for looking at, plasma focusing and wakefield acceleration of positron

  13. Ultra-low emittance beam generation using two-color ionization injection in a CO2 laser-driven plasma accelerator

    E-Print Network [OSTI]

    Schroeder, C B; Bulanov, S S; Chen, M; Esarey, E; Geddes, C G R; Vay, J -L; Yu, L -L; Leemans, W P

    2015-01-01T23:59:59.000Z

    Ultra-low emittance (tens of nm) beams can be generated in a plasma accelerator using ionization injection of electrons into a wakefield. An all-optical method of beam generation uses two laser pulses of different colors. A long-wavelength drive laser pulse (with a large ponderomotive force and small peak electric field) is used to excite a large wakefield without fully ionizing a gas, and a short-wavelength injection laser pulse (with a small ponderomotive force and large peak electric field), co-propagating and delayed with respect to the pump laser, to ionize a fraction of the remaining bound electrons at a trapped wake phase, generating an electron beam that is accelerated in the wake. The trapping condition, the ionized electron distribution, and the trapped bunch dynamics are discussed. Expressions for the beam transverse emittance, parallel and orthogonal to the ionization laser polarization, are presented. An example is shown using a 10-micron CO2 laser to drive the wake and a frequency-doubled Ti:Al2...

  14. Method of casting patterned dielectric structures

    DOE Patents [OSTI]

    Poco, John F. (Livermore, CA); Hrubesh, Lawrence W. (Livermore, CA)

    2001-01-01T23:59:59.000Z

    A pattern of dielectric structures are formed directly on a substrate in a single step using sol-gel chemistry and molding procedures. The resulting dielectric structures are useful in vacuum applications for electronic devices. Porous, lightweight structures having a high aspect ratio that are suitable for use as spacers between the faceplate and baseplate of a field emission display can be manufactured using this method.

  15. Thin film dielectric composite materials

    DOE Patents [OSTI]

    Jia, Quanxi (Los Alamos, NM); Gibbons, Brady J. (Los Alamos, NM); Findikoglu, Alp T. (Los Alamos, NM); Park, Bae Ho (Los Alamos, NM)

    2002-01-01T23:59:59.000Z

    A dielectric composite material comprising at least two crystal phases of different components with TiO.sub.2 as a first component and a material selected from the group consisting of Ba.sub.1-x Sr.sub.x TiO.sub.3 where x is from 0.3 to 0.7, Pb.sub.1-x Ca.sub.x TiO.sub.3 where x is from 0.4 to 0.7, Sr.sub.1-x Pb.sub.x TiO.sub.3 where x is from 0.2 to 0.4, Ba.sub.1-x Cd.sub.x TiO.sub.3 where x is from 0.02 to 0.1, BaTi.sub.1-x Zr.sub.x O.sub.3 where x is from 0.2 to 0.3, BaTi.sub.1-x Sn.sub.x O.sub.3 where x is from 0.15 to 0.3, BaTi.sub.1-x Hf.sub.x O.sub.3 where x is from 0.24 to 0.3, Pb.sub.1-1.3x La.sub.x TiO.sub.3+0.2x where x is from 0.23 to 0.3, (BaTiO.sub.3).sub.x (PbFeo.sub.0.5 Nb.sub.0.5 O.sub.3).sub.1-x where x is from 0.75 to 0.9, (PbTiO.sub.3).sub.- (PbCo.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.1 to 0.45, (PbTiO.sub.3).sub.x (PbMg.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.2 to 0.4, and (PbTiO.sub.3).sub.x (PbFe.sub.0.5 Ta.sub.0.5 O.sub.3).sub.1-x where x is from 0 to 0.2, as the second component is described. The dielectric composite material can be formed as a thin film upon suitable substrates.

  16. Non-linear Ion-wake Excitation by Ultra-relativistic Electron Wakefields

    E-Print Network [OSTI]

    Sahai, Aakash A

    2015-01-01T23:59:59.000Z

    The excitation of a non-linear ion-wake by a train of ultra-relativistic plasmons is modeled and its use for a novel regime of positron acceleration is explored. Its channel-like structure is independent of the energy-source driving the bubble-shaped slowly-propagating high phase-velocity electron density waves. The back of the bubble electron compression sucks-in the ions and the space-charge within the bubble expels them, forming a near-void channel with on-axis and bubble-edge density-spikes. The channel-edge density-spike is driven radially outwards as a non-linear ion acoustic-wave by the wake electron thermal pressure. OSIRIS PIC simulations are used to study the ion-wake structure, its evolution and its use for positron acceleration.

  17. Application of SiO2 aerogel film with low dielectric constant to intermetal dielectrics

    E-Print Network [OSTI]

    Jo, Moon-Ho

    Application of SiO2 aerogel film with low dielectric constant to intermetal dielectrics Moon-Ho Jo aerogel film was characterized from its structural and chemical viewpoints. High porosity of material infrared spectroscopy (FT-IR) for their chemical states. The improved electrical properties of SiO2 aerogel

  18. Some Frontiers of Accelerator Physics

    E-Print Network [OSTI]

    Sessler, Andrew M.

    2008-01-01T23:59:59.000Z

    Some Frontiers of Accelerator Physics A.M. Sessler OctoberSOME FRONTIERS OF ACCELERATOR PHYSICS* Andrew M. Sessleris Some Frontiers of Accelerator Physics and it is most

  19. Application of Plasma Waveguides to High Energy Accelerators

    SciTech Connect (OSTI)

    Milchberg, Howard M

    2013-03-30T23:59:59.000Z

    The eventual success of laser-plasma based acceleration schemes for high-energy particle physics will require the focusing and stable guiding of short intense laser pulses in reproducible plasma channels. For this goal to be realized, many scientific issues need to be addressed. These issues include an understanding of the basic physics of, and an exploration of various schemes for, plasma channel formation. In addition, the coupling of intense laser pulses to these channels and the stable propagation of pulses in the channels require study. Finally, new theoretical and computational tools need to be developed to aid in the design and analysis of experiments and future accelerators. Here we propose a 3-year renewal of our combined theoretical and experimental program on the applications of plasma waveguides to high-energy accelerators. During the past grant period we have made a number of significant advances in the science of laser-plasma based acceleration. We pioneered the development of clustered gases as a new highly efficient medium for plasma channel formation. Our contributions here include theoretical and experimental studies of the physics of cluster ionization, heating, explosion, and channel formation. We have demonstrated for the first time the generation of and guiding in a corrugated plasma waveguide. The fine structure demonstrated in these guides is only possible with cluster jet heating by lasers. The corrugated guide is a slow wave structure operable at arbitrarily high laser intensities, allowing direct laser acceleration, a process we have explored in detail with simulations. The development of these guides opens the possibility of direct laser acceleration, a true miniature analogue of the SLAC RF-based accelerator. Our theoretical studies during this period have also contributed to the further development of the simulation codes, Wake and QuickPIC, which can be used for both laser driven and beam driven plasma based acceleration schemes. We will continue our development of advanced simulation tools by modifying the QuickPIC algorithm to allow for the simulation of plasma particle pick-up by the wake fields. We have also performed extensive simulations of plasma slow wave structures for efficient THz generation by guided laser beams or accelerated electron beams. We will pursue experimental studies of direct laser acceleration, and THz generation by two methods, ponderomotive-induced THz polarization, and THz radiation by laser accelerated electron beams. We also plan to study both conventional and corrugated plasma channels using our new 30 TW in our new lab facilities. We will investigate production of very long hydrogen plasma waveguides (5 cm). We will study guiding at increasing power levels through the onset of laser-induced cavitation (bubble regime) to assess the role played by the preformed channel. Experiments in direct acceleration will be performed, using laser plasma wakefields as the electron injector. Finally, we will use 2-colour ionization of gases as a high frequency THz source (<60 THz) in order for femtosecond measurements of low plasma densities in waveguides and beams.

  20. Novel Methods in the Particle-In-Cell Accelerator Code-Framework Warp

    SciTech Connect (OSTI)

    Vay, J. -L.; Grote, D. P.; Cohen, R. H.; Friedman, A.; Grote, D. P.; Cohen, R. H.; Friedman, A.

    2011-09-01T23:59:59.000Z

    The Particle-In-Cell (PIC) Code-Framework Warp is being developed by the Heavy Ion Fusion Science Virtual National Laboratory (HIFS-VNL) to guide the development of accelerators that can deliver beams suitable for high energy density experiments and implosion of inertial fusion capsules. It is also applied in various areas outside the Heavy Ion Fusion program to the study and design of existing and next-generation high-energy accelerators, including the study of electron cloud effects and laser wakefield acceleration for example. This paper presents an overview of Warp’s capabilities, summarizing recent original numerical methods that were developed by the HIFS-VNL (including Particle-In-Cell with Adaptive Mesh Refinement, a large-timestep “drift-Lorentz” mover for arbitrarily magnetized species, a relativistic Lorentz invariant leapfrog particle pusher, simulations in Lorentz boosted frames, an electromagnetic solver with tunable numerical dispersion and efficient stride20 based digital filtering), with great emphasis on the description of the mesh refinement capability. Selected examples of applications of the methods to the abovementioned fields are given.

  1. Entanglement of Accelerating Particles

    E-Print Network [OSTI]

    W. L. Ku; M. -C. Chu

    2007-09-03T23:59:59.000Z

    We study how the entanglement of a maximally entangled pair of particles is affected when one or both of the pair are uniformly accelerated, while the detector remains in an inertial frame. We find that the entanglement is unchanged if all degrees of freedom are considered. However, particle pairs are produced, and the entanglements of different bipartite systems may change with the acceleration. In particular, the entanglement between accelerating fermions is transferred preferentially to the produced antiparticles when the acceleration is large, and the entanglement transfer is complete when the acceleration approaches infinity. However, for scalar particles, no entanglement transfer to the antiparticles is observed.

  2. Automated detection and analysis of particle beams in laser-plasma accelerator simulations

    SciTech Connect (OSTI)

    Ushizima, Daniela Mayumi; Geddes, C.G.; Cormier-Michel, E.; Bethel, E. Wes; Jacobsen, J.; Prabhat, ,; R.ubel, O.; Weber, G,; Hamann, B.

    2010-05-21T23:59:59.000Z

    Numerical simulations of laser-plasma wakefield (particle) accelerators model the acceleration of electrons trapped in plasma oscillations (wakes) left behind when an intense laser pulse propagates through the plasma. The goal of these simulations is to better understand the process involved in plasma wake generation and how electrons are trapped and accelerated by the wake. Understanding of such accelerators, and their development, offer high accelerating gradients, potentially reducing size and cost of new accelerators. One operating regime of interest is where a trapped subset of electrons loads the wake and forms an isolated group of accelerated particles with low spread in momentum and position, desirable characteristics for many applications. The electrons trapped in the wake may be accelerated to high energies, the plasma gradient in the wake reaching up to a gigaelectronvolt per centimeter. High-energy electron accelerators power intense X-ray radiation to terahertz sources, and are used in many applications including medical radiotherapy and imaging. To extract information from the simulation about the quality of the beam, a typical approach is to examine plots of the entire dataset, visually determining the adequate parameters necessary to select a subset of particles, which is then further analyzed. This procedure requires laborious examination of massive data sets over many time steps using several plots, a routine that is unfeasible for large data collections. Demand for automated analysis is growing along with the volume and size of simulations. Current 2D LWFA simulation datasets are typically between 1GB and 100GB in size, but simulations in 3D are of the order of TBs. The increase in the number of datasets and dataset sizes leads to a need for automatic routines to recognize particle patterns as particle bunches (beam of electrons) for subsequent analysis. Because of the growth in dataset size, the application of machine learning techniques for scientific data mining is increasingly considered. In plasma simulations, Bagherjeiran et al. presented a comprehensive report on applying graph-based techniques for orbit classification. They used the KAM classifier to label points and components in single and multiple orbits. Love et al. conducted an image space analysis of coherent structures in plasma simulations. They used a number of segmentation and region-growing techniques to isolate regions of interest in orbit plots. Both approaches analyzed particle accelerator data, targeting the system dynamics in terms of particle orbits. However, they did not address particle dynamics as a function of time or inspected the behavior of bunches of particles. Ruebel et al. addressed the visual analysis of massive laser wakefield acceleration (LWFA) simulation data using interactive procedures to query the data. Sophisticated visualization tools were provided to inspect the data manually. Ruebel et al. have integrated these tools to the visualization and analysis system VisIt, in addition to utilizing efficient data management based on HDF5, H5Part, and the index/query tool FastBit. In Ruebel et al. proposed automatic beam path analysis using a suite of methods to classify particles in simulation data and to analyze their temporal evolution. To enable researchers to accurately define particle beams, the method computes a set of measures based on the path of particles relative to the distance of the particles to a beam. To achieve good performance, this framework uses an analysis pipeline designed to quickly reduce the amount of data that needs to be considered in the actual path distance computation. As part of this process, region-growing methods are utilized to detect particle bunches at single time steps. Efficient data reduction is essential to enable automated analysis of large data sets as described in the next section, where data reduction methods are steered to the particular requirements of our clustering analysis. Previously, we have described the application of a set of algorithms to automate the data analys

  3. Method of fabricating a solar cell with a tunnel dielectric layer

    DOE Patents [OSTI]

    Dennis, Tim; Harrington, Scott; Manning, Jane; Smith, David; Waldhauer, Ann

    2012-12-18T23:59:59.000Z

    Methods of fabricating solar cells with tunnel dielectric layers are described. Solar cells with tunnel dielectric layers are also described.

  4. Method of fabricating a solar cell with a tunnel dielectric layer

    DOE Patents [OSTI]

    Dennis, Tim; Harrington, Scott; Manning, Jane; Smith, David D; Waldhauer, Ann

    2014-04-29T23:59:59.000Z

    Methods of fabricating solar cells with tunnel dielectric layers are described. Solar cells with tunnel dielectric layers are also described.

  5. High brightness electron accelerator

    DOE Patents [OSTI]

    Sheffield, Richard L. (Los Alamos, NM); Carlsten, Bruce E. (Los Alamos, NM); Young, Lloyd M. (Los Alamos, NM)

    1994-01-01T23:59:59.000Z

    A compact high brightness linear accelerator is provided for use, e.g., in a free electron laser. The accelerator has a first plurality of acclerating cavities having end walls with four coupling slots for accelerating electrons to high velocities in the absence of quadrupole fields. A second plurality of cavities receives the high velocity electrons for further acceleration, where each of the second cavities has end walls with two coupling slots for acceleration in the absence of dipole fields. The accelerator also includes a first cavity with an extended length to provide for phase matching the electron beam along the accelerating cavities. A solenoid is provided about the photocathode that emits the electons, where the solenoid is configured to provide a substantially uniform magnetic field over the photocathode surface to minimize emittance of the electons as the electrons enter the first cavity.

  6. RF properties of periodic accelerating structures for linear colliders

    SciTech Connect (OSTI)

    Wang, J.W.

    1989-07-01T23:59:59.000Z

    With the advent of the SLAC electron-positron linear collider (SLC) in the 100 GeV center-of-mass energy range, research and development work on even higher energy machines of this type has started in several laboratories in the United States, Europe, the Soviet Union and Japan. These linear colliders appear to provide the only promising approach to studying e/sup /plus//e/sup /minus// physics at center-of-mass energies approaching 1 TeV. This thesis concerns itself with the study of radio frequency properties of periodic accelerating structures for linear colliders and their interaction with bunched beams. The topics that have been investigated are: experimental measurements of the energy loss of single bunches to longitudinal modes in two types of structures, using an equivalent signal on a coaxial wire to simulate the beam; a method of canceling the energy spread created within a single bunch by longitudinal wakefields, through appropriate shaping of the longitudinal charge distribution of the bunch; derivation of the complete transient beam-loading equation for a train of bunches passing through a constant-gradient accelerator section, with application to the calculation and minimization of multi-bunch energy spread; detailed study of field emission and radio frequency breakdown in disk-loaded structures at S-, C- and X-band frequencies under extremely high-gradient conditions, with special attention to thermal effects, radiation, sparking, emission of gases, surface damage through explosive emission and its possible control through RF-gas processing. 53 refs., 49 figs., 9 tabs.

  7. Curvature-directed Crystallization of Polymer Dielectrics in Nanopores

    E-Print Network [OSTI]

    Reid, Dariya

    2013-11-26T23:59:59.000Z

    . BROADBAND DIELECTRIC SPECTROSCOPY…………………………………. 44 vii 5.1 Introduction to Broadband Dielectric Spectroscopy of iPP-Filled AAO Templates……………………………………………………………………….. 44 5.2 Sample BDS Data of iPP-Filled AAO Templates……………………………… 45 6...

  8. Method for fabrication of crack-free ceramic dielectric films

    DOE Patents [OSTI]

    Ma, Beihai; Balachandran, Uthamalingam; Chao, Sheng; Liu, Shanshan; Narayanan, Manoj

    2014-02-11T23:59:59.000Z

    The invention provides a process for forming crack-free dielectric films on a substrate. The process comprise the application of a dielectric precursor layer of a thickness from about 0.3 .mu.m to about 1.0 .mu.m to a substrate. The deposition is followed by low temperature heat pretreatment, prepyrolysis, pyrolysis and crystallization step for each layer. The deposition, heat pretreatment, prepyrolysis, pyrolysis and crystallization are repeated until the dielectric film forms an overall thickness of from about 1.5 .mu.m to about 20.0 .mu.m and providing a final crystallization treatment to form a thick dielectric film. Also provided was a thick crack-free dielectric film on a substrate, the dielectric forming a dense thick crack-free dielectric having an overall dielectric thickness of from about 1.5 .mu.m to about 20.0 .mu.m.

  9. Tuneable dielectric films having low electrical losses

    DOE Patents [OSTI]

    Dimos, Duane Brian (Albuquerque, NM); Schwartz, Robert William (Albuquerque, NM); Raymond, Mark Victor (Albuquerque, NM); Al-Shareef, Husam Niman (Boise, ID); Mueller, Carl (Lakewood, CO); Galt, David (Denver, CO)

    2000-01-01T23:59:59.000Z

    The present invention is directed to a method for forming dielectric thin films having substantially reduced electrical losses at microwave and millimeter wave frequencies relative to conventional dielectric thin films. The reduction in losses is realized by dramatically increasing the grain sizes of the dielectric films, thereby minimizing intergranular scattering of the microwave signal due to grain boundaries and point defects. The increase in grain size is realized by heating the film to a temperature at which the grains experience regrowth. The grain size of the films can be further increased by first depositing the films with an excess of one of the compoents, such that a highly mobile grain boundary phase is formed.

  10. Polyamide 66 as a Cryogenic Dielectric

    SciTech Connect (OSTI)

    Tuncer, Enis [ORNL; Polyzos, Georgios [ORNL; Sauers, Isidor [ORNL; James, David Randy [ORNL; Ellis, Alvin R [ORNL; Messman, Jamie M [ORNL; Aytug, Tolga [ORNL

    2009-01-01T23:59:59.000Z

    Improvements in superconductor and cryogenic technologies enable novel power apparatus, \\eg, cables, transformers, fault current limiters, generators, \\etc, with better device characteristics than their conventional counterparts. In these applications electrical insulation materials play an important role in system weight, footprint (size), and voltage level. The trend in the electrical insulation material selection has been to adapt or to employ conventional insulation materials to these new systems. However, at low temperatures, thermal contraction and loss of mechanical strength in many materials make them unsuitable for superconducting power applications. In this paper, a widely used commercial material was characterized as a potential cryogenic dielectric. The material is used in ``oven bag'' a heat-resistant polyamide (nylon) used in cooking (produced by Reynolds\\textregistered, Richmond, VA, USA). It is first characterized by Fourier transform infrared and x-ray diffraction techniques and determined to be composed of polyamide 66 (PA66) polymer. Secondly the complex dielectric permittivity and dielectric breakdown strength of the PA66 films are investigated. The dielectric data are then compared with data reported in the literature. A comparison of dielectric strength with a widely used high-temperature superconductor electrical insulation material, polypropylene-laminated paper (PPLP\\texttrademark\\ a product of Sumitomo Electric Industries, Japan), is provided. It is observed that the statistical analysis of the PA66 films yields 1\\% failure probability at $127\\ \\kilo\\volt\\milli\\meter^{-1}$; this value is approximately $46\\ \\kilo\\volt\\milli\\meter^{-1}$ higher than PPLP\\texttrademark. It is concluded that PA66 may be a good candidate for cryogenic applications. Finally, a summary of dielectric properties of some of the commercial tape insulation materials and various polymers is also provided.

  11. Investigation of dielectric overlay microstrip circuits

    E-Print Network [OSTI]

    Klein, James Louis

    1988-01-01T23:59:59.000Z

    values are caused by unequal coupling for different modes of operation. To correct these problems a dielectric overlay may be implemented. The overlay is simply a section of dielectric placed on top of the microstrip conductor. Fig. 1 shows the overlay... to unequal velocities for even- and odd-modes of excitation [1]. The unequal phase velocities are due to the amount of coupling between conductors that exist for each mode. Strong coupling for the odd-mode versus weak coupling for the even-mode create...

  12. Method for producing high dielectric strength microvalves

    DOE Patents [OSTI]

    Kirby, Brian J. (San Francisco, CA); Reichmuth, David S. (Oakland, CA); Shepodd, Timothy J. (Livermore, CA)

    2006-04-04T23:59:59.000Z

    A microvalve having a cast-in-place and lithographically shaped mobile, polymer monolith for fluid flow control in microfluidic devices and method of manufacture. The microvalve contains a porous fluorinated polymer monolithic element whose pores are filled with an electrically insulating, high dielectric strength fluid, typically a perfluorinated liquid. This combination provides a microvalve that combines high dielectric strength with extremely low electrical conductivity. These microvalves have been shown to have resistivities of at least 100 G.OMEGA. and are compatible with solvents such as water at a pH between 2.7 and 9.0, 1-1 propanol, acetonitrile, and acetone.

  13. Norbornylene-based polymer systems for dielectric applications

    DOE Patents [OSTI]

    Dirk, Shawn M. (Albuquerque, NM); Wheeler, David R. (Albuquerque, NM)

    2012-07-17T23:59:59.000Z

    A capacitor having at least one electrode pair being separated by a dielectric component, with the dielectric component being made of a polymer such as a norbornylene-containing polymer with a dielectric constant greater than 3 and a dissipation factor less than 0.1 where the capacitor has an operating temperature greater than 100.degree. C. and less than 170.degree. C.

  14. Leaky Fermi accelerators

    E-Print Network [OSTI]

    Shah, Kushal; Rom-Kedar, Vered; Turaev, Dmitry

    2015-01-01T23:59:59.000Z

    A Fermi accelerator is a billiard with oscillating walls. A leaky accelerator interacts with an environment of an ideal gas at equilibrium by exchange of particles through a small hole on its boundary. Such interaction may heat the gas: we estimate the net energy flow through the hole under the assumption that the particles inside the billiard do not collide with each other and remain in the accelerator for sufficiently long time. The heat production is found to depend strongly on the type of the Fermi accelerator. An ergodic accelerator, i.e. one which has a single ergodic component, produces a weaker energy flow than a multi-component accelerator. Specifically, in the ergodic case the energy gain is independent of the hole size, whereas in the multi-component case the energy flow may be significantly increased by shrinking the hole size.

  15. Ceramic-polymer nanocomposites with increased dielectric permittivity and low dielectric loss

    SciTech Connect (OSTI)

    Bhardwaj, Sumit, E-mail: sumit.bhardwaj4@gmail.com; Paul, Joginder, E-mail: sumit.bhardwaj4@gmail.com [Centre for Materials Science and Engineering, National Institute of Technology, Hamirpur -177 005 (India); Raina, K. K. [School of Physics and Materials Science, Thapar University, Patiala -147 004 (India); Thakur, N. S. [Centre for Energy and Environment, National Institute of Technology, Hamirpur -177005 (India); Kumar, Ravi [Centre for Materials Science and Engineering, National Institute of Technology, Hamirpur -177 005 (India); Beant College of Engineering and Technology, Gurdaspur -143521 (India)

    2014-04-24T23:59:59.000Z

    The use of lead free materials in device fabrication is very essential from environmental point of view. We have synthesized the lead free ferroelectric polymer nanocomposite films with increased dielectric properties. Lead free bismuth titanate has been used as active ceramic nanofillers having crystallite size 24nm and PVDF as the polymer matrix. Ferroelectric ?-phase of the polymer composite films was confirmed by X-ray diffraction pattern. Mapping data confirms the homogeneous dispersion of ceramic particles into the polymer matrix. Frequency dependent dielectric constant increases up to 43.4 at 100Hz, whereas dielectric loss decreases with 7 wt% bismuth titanate loading. This high dielectric constant lead free ferroelectric polymer films can be used for energy density applications.

  16. Optically pulsed electron accelerator

    DOE Patents [OSTI]

    Fraser, J.S.; Sheffield, R.L.

    1985-05-20T23:59:59.000Z

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radiofrequency-powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  17. Optically pulsed electron accelerator

    DOE Patents [OSTI]

    Fraser, John S. (Los Alamos, NM); Sheffield, Richard L. (Los Alamos, NM)

    1987-01-01T23:59:59.000Z

    An optically pulsed electron accelerator can be used as an injector for a free electron laser and comprises a pulsed light source, such as a laser, for providing discrete incident light pulses. A photoemissive electron source emits electron bursts having the same duration as the incident light pulses when impinged upon by same. The photoemissive electron source is located on an inside wall of a radio frequency powered accelerator cell which accelerates the electron burst emitted by the photoemissive electron source.

  18. PUBLISHED ONLINE: 12 APRIL 2009; CORRECTED ONLINE: 24 APRIL 2009 | DOI: 10.1038/NPHYS1248 Proton-driven plasma-wakefield acceleration

    E-Print Network [OSTI]

    Loss, Daniel

    therefore be used for accel- erating particles to relativistic energies1­3 . Initially, laser-driven plasma to produce electric fields of 10­100 GV m-1 . This has opened up the possibility of building compact particle to the energy frontier of particle physics--the teraelectronvolt regime. Here, we introduce the possibility

  19. Advanced Accelerator Concepts Workshop

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    on high energy ion generation Levi Schachter Active Media Accelerators Benjamin Bowes Ultrafast 2-D radiative transport in a micron-scale aluminum plasma excited at...

  20. Accelerator Test Facility

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Test Facility Vitaly Yakimenko October 6-7, 2010 ATF User meeting DOE HE, S. Vigdor, ALD - (Contact) T. Ludlam Chair, Physics Department V. Yakimenko Director ATF, Accelerator...

  1. Accelerator Concepts Workshop

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Colliders to Synchrotron Radiation Sources. The wide scope of the workshop includes new methods of particle acceleration to high energies, techniques for production of...

  2. Charged particle accelerator grating

    DOE Patents [OSTI]

    Palmer, Robert B. (Shoreham, NY)

    1986-01-01T23:59:59.000Z

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams into the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  3. Accelerator R&D

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Superconducting RF Module with a PBG Coupler Cell, 2013 North American Particle Accelerator Conference, Pasadena, CA, September 29 - October 4th, 2013. Evgenya I. Simakov,...

  4. Market Acceleration (Fact Sheet)

    SciTech Connect (OSTI)

    Not Available

    2010-09-01T23:59:59.000Z

    The fact sheet summarizes the goals and activities of the DOE Solar Energy Technologies Program efforts within its market acceleration subprogram.

  5. Characteristics of radio-frequency atmospheric pressure dielectric-barrier discharge with dielectric electrodes

    SciTech Connect (OSTI)

    Hussain, S., E-mail: shussain@uos.edu.pk, E-mail: shussainuos@yahoo.com; Qazi, H. I. A.; Badar, M. A. [Department of Physics, University of Sargodha, 40100 Sargodha (Pakistan)] [Department of Physics, University of Sargodha, 40100 Sargodha (Pakistan)

    2014-03-15T23:59:59.000Z

    An experimental investigation to characterize the properties and highlight the benefits of atmospheric pressure radio-frequency dielectric-barrier discharge (rf DBD) with dielectric electrodes fabricated by anodizing aluminium substrate is presented. The current-voltage characteristics and millisecond images are used to distinguish the ? and ? modes. This atmospheric rf DBD is observed to retain the discharge volume without constriction in ? mode. Optical emission spectroscopy demonstrates that the large discharge current leads to more abundant reactive species in this plasma source.

  6. Community petascale project for accelerator science and simulation: Advancing computational science for future accelerators and accelerator technologies

    E-Print Network [OSTI]

    Spentzouris, Panagiotis

    2008-01-01T23:59:59.000Z

    program for computational accelerator physics development isof computational accelerator physics applications, withof computational accelerator physics. Under ComPASS, the

  7. Neutrino physics at accelerators

    E-Print Network [OSTI]

    Enrique Fernandez

    2006-07-16T23:59:59.000Z

    Present and future neutrino experiments at accelerators are mainly concerned with understanding the neutrino oscillation phenomenon and its implications. Here a brief account of neutrino oscillations is given together with a description of the supporting data. Some current and planned accelerator neutrino experiments are also explained.

  8. Microscale acceleration history discriminators

    DOE Patents [OSTI]

    Polosky, Marc A. (Albuquerque, NM); Plummer, David W. (Albuquerque, NM)

    2002-01-01T23:59:59.000Z

    A new class of micromechanical acceleration history discriminators is claimed. These discriminators allow the precise differentiation of a wide range of acceleration-time histories, thereby allowing adaptive events to be triggered in response to the severity (or lack thereof) of an external environment. Such devices have applications in airbag activation, and other safety and surety applications.

  9. Accelerators (4/5)

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  10. Accelerators (5/5)

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  11. Safety of Accelerator Facilities

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2004-07-23T23:59:59.000Z

    To establish accelerator-specific safety requirements which, when supplemented by other applicable safety and health requirements, will serve to prevent injuries and illnesses associated with Department of Energy (DOE) or National Nuclear Security Administration (NNSA) accelerator operations. Cancels DOE O 420.2A. Certified 5-13-08. Canceled by DOE O 420.2C.

  12. Accelerators (3/5)

    ScienceCinema (OSTI)

    None

    2011-10-06T23:59:59.000Z

    1a) Introduction and motivation 1b) History and accelerator types 2) Transverse beam dynamics 3a) Longitudinal beam dynamics 3b) Figure of merit of a synchrotron/collider 3c) Beam control 4) Main limiting factors 5) Technical challenges Prerequisite knowledge: Previous knowledge of accelerators is not required.

  13. Safety of Accelerator Facilities

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2011-07-21T23:59:59.000Z

    The order defines accelerators and establishes accelerator specific safety requirements and approval authorities which, when supplemented by other applicable safety and health requirements, promote safe operations to ensure protection of workers, the public, and the environment. Cancels DOE O 420.2B.

  14. Safety of Accelerator Facilities

    Broader source: Directives, Delegations, and Requirements [Office of Management (MA)]

    2001-01-08T23:59:59.000Z

    To establish accelerator-specific safety requirements which, when supplemented by other applicable safety and health requirements, will serve to prevent injuries and illnesses associated with Department of Energy (DOE) or National Nuclear Security Administration (NNSA) accelerator operations. Cancels DOE O 420.2. Canceled by DOE O 420.2B.

  15. Beam emittance from coherent Cherenkov radiation in a solid dielectric

    SciTech Connect (OSTI)

    Richardson, R.D.; Platt, R.C. [Science Applications International Corp., Albuquerque, NM (United States); Crist, C.E. [Sandia National Labs., Albuquerque, NM (United States)

    1993-06-01T23:59:59.000Z

    We report experimental insults of a technique for direct measurement of the emittance in high energy beams. This technique is analogous to the well known ``pepper pot`` masking approach, but with no upper limit on particle energy. Single shot emittance profiles were obtained on the 10 kA, 4 MeV SNL electron Recirculating Linear Accelerator showing agreement with theory and with alternate emittance measurements. Coherent (i.e., not strongly scattered or diffused) Cherenkov radiation from a flat, transparent, range-thin dielectric foil was split by an array of mirrors in order to view the emission profile up to a divergence angle of 70{degrees}. The mirrors were imaged by a distant telescope attached to an intensified, 2 ns video framing camera. The relative intensity profiles of the multiple images were unfolded using the properties of classical Cherenkov emission and geometric optics to obtain directly, without precise knowledge of other beam parameters, the transverse velocity distribution in the viewing plane. In our case the rms emittance was directly proportional to the product of the beam diameter and the transverse velocity spread. This and prior research efforts indicate applicability over a wide range of high energy beam parameters.

  16. Accelerated Quantum Dynamics

    E-Print Network [OSTI]

    Lynch, Morgan H

    2015-01-01T23:59:59.000Z

    In this paper we establish a formalism for the computation of observables due to acceleration-induced particle physics processes. General expressions for the transition rate, multiplicity, power, spectra, and displacement law of particles undergoing time-dependent acceleration and transitioning into a final state of arbitrary particle number are obtained. The transition rate, power, and spectra are characterised by unique polynomials of multiplicity and thermal distributions of both bosonic and fermionic statistics. The acceleration dependent multiplicity is computed in terms of the branching fractions of the associated inertial processes. The displacement law of the spectra predicts the energy of the emitted particles are directly proportional to the accelerated temperature. These results extend our understanding of particle physics into the high acceleration sector.

  17. Investigation on dielectric properties of atomic layer deposited Al{sub 2}O{sub 3} dielectric films

    SciTech Connect (OSTI)

    Y?ld?z, Dilber Esra [Department of Physics, Faculty of Arts and Sciences, Hitit University, Çorum 19030 (Turkey); Y?ld?r?m, Mert; Gökçen, Muharrem [Department of Physics, Faculty of Arts and Sciences, Düzce University, Düzce 81620 (Turkey)

    2014-05-15T23:59:59.000Z

    Al/Al{sub 2}O{sub 3}/p-Si Schottky barrier diodes (SBDs) were fabricated using atomic layer deposition technique in order to investigate dielectric properties of SBDs. For this purpose, admittance measurements were conducted at room temperature between ?1?V and 3?V in the frequency range of 10 kHz and 1?MHz. In addition to the investigation of Al{sub 2}O{sub 3} morphology using atomic force microscope, dielectric parameters; such as dielectric constant (??), dielectric loss (??), dielectric loss tangent (tan??), and real and imaginary parts of dielectric modulus (M? and M?, respectively), were calculated and effect of frequency on these parameters of Al/Al{sub 2}O{sub 3}/p-Si SBDs was discussed. Variations in these parameters at low frequencies were associated with the effect of interface states in low frequency region. Besides dielectric parameters, ac electrical conductivity of these SBDs was also investigated.

  18. Compensation of wakefield-driven energy spread in energy recovery linacs Georg H. Hoffstaetter and Yang Hao Lau

    E-Print Network [OSTI]

    Hoffstaetter, Georg

    and Yang Hao Lau Cornell University, Ithaca, New York 14853, USA (Received 16 May 2008; published 23 July, so that their energy is available for the acceleration of new particles. During this deceleration at a decelerating phase to recover the particles' energy. This energy is then used to accelerate new bunches

  19. Dielectric anisotropy in polar solvents under external fields

    E-Print Network [OSTI]

    Sahin Buyukdagli

    2014-12-14T23:59:59.000Z

    We investigate dielectric saturation and increment in polar liquids under external fields. We couple a previously introduced dipolar solvent model to a uniform electric field and derive the electrostatic kernel of interacting dipoles. This procedure allows an unambiguous definition of the liquid dielectric permittivity embodying non-linear dielectric response and correlation effects.We find that the presence of the external field results in a dielectric anisotropy characterized by a two-component dielectric permittivity tensor. The increase of the electric field amplifies the permittivity component parallel to the field direction, i.e. dielectric increment is observed along the field. However, the perpendicular component is lowered below the physiological permittivity, indicating dielectric saturation perpendicular to the field. By comparison with Molecular Dynamics simulations from the literature, we show that the mean-field level dielectric response theory underestimates dielectric saturation. The inclusion of dipolar correlations at the weak-coupling level intensify the mean-field level dielectric saturation and improves the agreement with simulation data at weak electric fields. The correlation-corrected theory predicts as well the presence of a metastable configuration corresponding to the antiparallel alignment of dipoles with the field. This prediction can be verified by solvent-explicit simulations where solvent molecules are expected to be trapped transiently in this metastable state.

  20. Jar mechanism accelerator

    SciTech Connect (OSTI)

    Anderson, E.A.; Webb, D.D.

    1989-07-11T23:59:59.000Z

    This patent describes an accelerator for use with a jar mechanism in a well pipe string to enhance the jarring impact delivered to a stuck object wherein the jar mechanism includes inner and outer members for connection, respectively, between the well pipe string the stuck object. The jar mechanism members are constructed to (1) restrict relative longitudinal movement therebetween to build up energy in the well pipe string and accelerator and then (2) to release the jar mechanism members for unrestrained, free relative longitudinal movement therebetween to engage jarring surfaces on the jar mechanism members for delivering a jarring impact to the stuck object. The accelerator includes: inner and outer telescopically connected members relatively movable longitudinally to accumulate energy in the accelerator; the inner and outer accelerator members each having means for connecting the accelerator in the well pipe string; means associated with the inner and outer members for initially accomodating a predetermined minimum length of unrestrained, free relative longitudinal movement between the inner and outer accelerator members.

  1. Dielectric studies of water absorbed in epoxies 

    E-Print Network [OSTI]

    Pham, Ha Quoc

    1987-01-01T23:59:59.000Z

    . They are used in many applications such as surface coatings, adhesives, elqctronic encapsulation and structural composites. Water absorption in epoxy resins is known to be detrimental to resin performances. One example is the unusually large lowering... ent) Nay 1987 ABSTRACT Dielectric Studies of Mater Absorbed in Epoxies. (May 1987) Ha I)uoc Pham, B. S. , Tokyo University of Agriculture Chairman of Advisory Committee: C. A. J. Hoeve Epoxy resins are industrially important polymers...

  2. Dielectric Boundary Force in Biomolecular Solvation

    E-Print Network [OSTI]

    Li, Bo

    for Theoretical Biological Physics UC San Diego Funding: NIH and NSF Applied Mathematics and Analysis Seminar vs. Implicit Molecular dynamics simulations Statistical Mechanics P(X, Y ) = P0e-U(X,Y )/kBT U(X, Y dielectric x Qi i w m =80 =1 w m Free-energy functional Gtotal[] = P Vol (m) + 0 (1 - 2H) dS + w w UvdW d

  3. Broadband Dielectric Spectroscopy on Human Blood

    E-Print Network [OSTI]

    M. Wolf; R. Gulich; P. Lunkenheimer; A. Loidl

    2011-05-25T23:59:59.000Z

    Dielectric spectra of human blood reveal a rich variety of dynamic processes. Achieving a better characterization and understanding of these processes not only is of academic interest but also of high relevance for medical applications as, e.g., the determination of absorption rates of electromagnetic radiation by the human body. The dielectric properties of human blood are studied using broadband dielectric spectroscopy, systematically investigating the dependence on temperature and hematocrit value. By covering a frequency range from 1 Hz to 40 GHz, information on all the typical dispersion regions of biological matter is obtained. We find no evidence for a low-frequency relaxation (alpha-relaxation) caused, e.g., by counterion diffusion effects as reported for some types of biological matter. The analysis of a strong Maxwell-Wagner relaxation arising from the polarization of the cell membranes in the 1-100 MHz region (beta-relaxation) allows for the test of model predictions and the determination of various intrinsic cell properties. In the microwave region beyond 1 GHz, the reorientational motion of water molecules in the blood plasma leads to another relaxation feature (gamma-relaxation). Between beta- and gamma-relaxation, significant dispersion is observed, which, however, can be explained by a superposition of these relaxation processes and is not due to an additional delta-relaxation often found in biological matter. Our measurements provide dielectric data on human blood of so far unsurpassed precision for a broad parameter range. All data are provided in electronic form to serve as basis for the calculation of the absorption rate of electromagnetic radiation and other medical purposes. Moreover, by investigating an exceptionally broad frequency range, valuable new information on the dynamic processes in blood is obtained.

  4. Charged particle accelerator grating

    DOE Patents [OSTI]

    Palmer, R.B.

    1985-09-09T23:59:59.000Z

    A readily disposable and replaceable accelerator grating for a relativistic particle accelerator is described. The grating is formed for a plurality of liquid droplets that are directed in precisely positioned jet streams to periodically dispose rows of droplets along the borders of a predetermined particle beam path. A plurality of lasers are used to direct laser beams onto the droplets, at predetermined angles, thereby to excite the droplets to support electromagnetic accelerating resonances on their surfaces. Those resonances operate to accelerate and focus particles moving along the beam path. As the droplets are distorted or destroyed by the incoming radiation, they are replaced at a predetermined frequency by other droplets supplied through the jet streams.

  5. Accelerator on a Chip

    ScienceCinema (OSTI)

    England, Joel

    2014-07-16T23:59:59.000Z

    SLAC's Joel England explains how the same fabrication techniques used for silicon computer microchips allowed their team to create the new laser-driven particle accelerator chips. (SLAC Multimedia Communications)

  6. BNL | Accelerator Test Facility

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    and new approaches to particle acceleration and x-ray generation. A next-generation ultra-fast CO2 laser based on chirped pulse amplification in isotopic gas mixtures is...

  7. CEBAF accelerator achievements

    SciTech Connect (OSTI)

    Y.C. Chao, M. Drury, C. Hovater, A. Hutton, G.A. Krafft, M. Poelker, C. Reece, M. Tiefenback

    2011-06-01T23:59:59.000Z

    In the past decade, nuclear physics users of Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF) have benefited from accelerator physics advances and machine improvements. As of early 2011, CEBAF operates routinely at 6 GeV, with a 12 GeV upgrade underway. This article reports highlights of CEBAF's scientific and technological evolution in the areas of cryomodule refurbishment, RF control, polarized source development, beam transport for parity experiments, magnets and hysteresis handling, beam breakup, and helium refrigerator operational optimization.

  8. Breakthrough: Fermilab Accelerator Technology

    ScienceCinema (OSTI)

    None

    2014-08-12T23:59:59.000Z

    There are more than 30,000 particle accelerators in operation around the world. At Fermilab, scientists are collaborating with other laboratories and industry to optimize the manufacturing processes for a new type of powerful accelerator that uses superconducting niobium cavities. Experimenting with unique polishing materials, a Fermilab team has now developed an efficient and environmentally friendly way of creating cavities that can propel particles with more than 30 million volts per meter.

  9. APT accelerator technology

    SciTech Connect (OSTI)

    Schneider, J.D.

    1996-09-01T23:59:59.000Z

    Proposed accelerator production of tritium (APT) project requires an accelerator providing a cw proton beam of 100 mA at 1300 MeV. Since most of the technical risk of a high-current cw (continuous-wave, 100% DF) accelerator resides in the low-energy section, Los Alamos is building a 20 MeV duplicate of the accelerator front end to confirm design codes, beam performance, and demonstrate operaional reliability. We report on design details of this low-energy demonstration accelerator (LEDA) and discuss the integrated design of the full accelerator for the APT plant. LEDA`s proton injector is under test and has produced more than 130 mA at 75 keV. Fabrication is proceeding on a 6.7-KeV, 8-m long RFQ, and detailed design is underway on coupled-cavity drift-tube linac (CCDTL) structures. Detailed design and technology experiments are underway on medium-beta superconducting cavities to assess feasibility of replacing the conventional (room-temperature copper) high-energy linac with a linac made of niobium superconducting RF cavities.

  10. Light propagation around a relativistic vortex flow of dielectric medium

    E-Print Network [OSTI]

    B. Linet

    2000-11-06T23:59:59.000Z

    We determine the path of the light around a dielectric vortex described by the relativistic vortex flow of a perfect fluid.

  11. Plasma-based accelerator structures

    SciTech Connect (OSTI)

    Schroeder, Carl B.

    1999-12-01T23:59:59.000Z

    Plasma-based accelerators have the ability to sustain extremely large accelerating gradients, with possible high-energy physics applications. This dissertation further develops the theory of plasma-based accelerators by addressing three topics: the performance of a hollow plasma channel as an accelerating structure, the generation of ultrashort electron bunches, and the propagation of laser pulses is underdense plasmas.

  12. Physically Based Rendering Intersection Acceleration

    E-Print Network [OSTI]

    Kazhdan, Michael

    Physically Based Rendering (600.657) Intersection Acceleration #12;Intersection Testing Accelerated partitions: Group objects into clusters Cluster volumes may overlap #12;Uniform (Voxel) Grid Acceleration Acceleration · Trace rays through grid cells ­ Fast ­ Incremental A B C D E F Only check primitives

  13. Fermilab | Science | Particle Accelerators | Fermilab's Accelerator Complex

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem NotEnergy,ARMFormsGasReleaseSpeechesHall A ThisFermilab's Accelerator Complex photo

  14. Fermilab | Science | Particle Accelerators | Leading Accelerator Technology

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem NotEnergy,ARMFormsGasReleaseSpeechesHall A ThisFermilab's Accelerator ComplexLeading

  15. Microelectromechanical acceleration-sensing apparatus

    DOE Patents [OSTI]

    Lee, Robb M. (Albuquerque, NM); Shul, Randy J. (Albuquerque, NM); Polosky, Marc A. (Albuquerque, NM); Hoke, Darren A. (Albuquerque, NM); Vernon, George E. (Rio Rancho, NM)

    2006-12-12T23:59:59.000Z

    An acceleration-sensing apparatus is disclosed which includes a moveable shuttle (i.e. a suspended mass) and a latch for capturing and holding the shuttle when an acceleration event is sensed above a predetermined threshold level. The acceleration-sensing apparatus provides a switch closure upon sensing the acceleration event and remains latched in place thereafter. Examples of the acceleration-sensing apparatus are provided which are responsive to an acceleration component in a single direction (i.e. a single-sided device) or to two oppositely-directed acceleration components (i.e. a dual-sided device). A two-stage acceleration-sensing apparatus is also disclosed which can sense two acceleration events separated in time. The acceleration-sensing apparatus of the present invention has applications, for example, in an automotive airbag deployment system.

  16. Chapter 17. High-Voltage Systems and Dielectric Materials High-Voltage Systems and Dielectric Materials

    E-Print Network [OSTI]

    -Voltage Systems and Dielectric Materials 17-2 RLE Progress Report 152 provides very useful insight into pre-breakdown in high voltage conduction and breakdown phenomena. 1. Mechanisms Behind Positive Streamers and Their Distinct Propagation Modes in Transformer Oil Sponsors This work was supported by ABB Corporate Research

  17. FACET: SLAC___s New User Facility

    SciTech Connect (OSTI)

    Clarke, C.I.; Decker, F.-J.; England, R.J.; Erickson, R.A.; Hast, C.; Hogan, M.J.; Li, S.Z.; Litos, M.D.; Nosochkov, Y.; Seeman, J.T.; Sheppard, J.; Wienands, U.; Woodley, M.; Yocky, G.; /SLAC

    2012-05-16T23:59:59.000Z

    FACET (Facility for Advanced Accelerator Experimental Tests) is a new User Facility at SLAC National Accelerator Laboratory. The first User Run started in spring 2012 with 20 GeV, 3 nC electron beams. The facility is designed to provide short (20 {micro}m) bunches and small (20 {micro}m wide) spot sizes, producing uniquely high power beams. FACET supports studies from many fields but in particular those of Plasma Wakefield Acceleration and Dielectric Wakefield Acceleration. The creation of drive and witness bunches and shaped bunch profiles is possible with 'Notch' Collimation. FACET is also a source of THz radiation for material studies. Positrons will be available at FACET in future user runs. We present the User Facility and the available tools and opportunities for future experiments.

  18. Experimental demonstration of superdirective dielectric antenna

    SciTech Connect (OSTI)

    Krasnok, Alexander E.; Filonov, Dmitry S.; Belov, Pavel A. [National Research University of Information Technologies, Mechanics and Optics (ITMO), St. Petersburg 197101 (Russian Federation); Simovski, Constantin R. [National Research University of Information Technologies, Mechanics and Optics (ITMO), St. Petersburg 197101 (Russian Federation); Aalto University, School of Electric and Electronic Engineering, Aalto FI76000 (Finland); Kivshar, Yuri S. [National Research University of Information Technologies, Mechanics and Optics (ITMO), St. Petersburg 197101 (Russian Federation); Nonlinear Physics Center, Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia)

    2014-03-31T23:59:59.000Z

    We propose and demonstrate experimentally a simple approach for achieving superdirectivity of emitted radiation for electrically small antennas based on a spherical dielectric resonator with a notch excited by a dipole source. Superdirectivity is achieved without using complex antenna arrays and for a wide range of frequencies. We also demonstrate the steering effect for a subwavelength displacement of the source. Finally, unlike previously known superdirective antennas, our design has significantly smaller losses, at the operation frequency radiation efficiency attains 80%, and matching holds in the 3%-wide frequency band without any special matching technique.

  19. Dielectric studies of water absorbed in epoxies

    E-Print Network [OSTI]

    Pham, Ha Quoc

    1987-01-01T23:59:59.000Z

    Comparison Solution Reported relative humidity X Water in films 1 Mater Na2S03/H2 NaN02/H2 CaC12/H20 100X 95X 9 293oK 66$ 8 293'K 33K Cd 293'K 14 1 Data from CRC's Handbook of ~Cba ist and ~ob sits and Nerck's Index. 25 100 80 50 40 0 20...DIELECTRIC STUDIES OF WATER ABSORBED IN EPOXIES A Thesis by HA QUOC PHAM Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1987 Major Subject...

  20. Modeling of dielectric elastomer as electromechanical resonator

    SciTech Connect (OSTI)

    Li, Bo, E-mail: liboxjtu@mail.xjtu.edu.cn; Liu, Lei; Chen, Hualing; Jia, Shuhai [School of Mechanical Engineering, Xi'an Jiaotong University, 28 Xianning West Road, Xi'an 710049 (China); State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, 28 Xianning West Road, Xi'an 710049 (China); Zhang, Junshi [State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi'an Jiaotong University, 28 Xianning West Road, Xi'an 710049 (China); School of Aerospace Engineering, Xi'an Jiaotong University, 28 Xianning West Road, Xi'an 710049 (China); Li, Dichen [School of Mechanical Engineering, Xi'an Jiaotong University, 28 Xianning West Road, Xi'an 710049 (China)

    2014-09-28T23:59:59.000Z

    Dielectric elastomers (DEs) feature nonlinear dynamics resulting from an electromechanical coupling. Under alternating voltage, the DE resonates with tunable performances. We present an analysis of the nonlinear dynamics of a DE as electromechanical resonator (DEER) configured as a pure shear actuator. A theoretical model is developed to characterize the complex performance under different boundary conditions. Physical mechanisms are presented and discussed. Chaotic behavior is also predicted, illustrating instabilities in the dynamics. The results provide a guide to the design and application of DEER in haptic devices.

  1. Dielectric Properties of PVDF/PZT

    SciTech Connect (OSTI)

    Zak, A. Khorsand; Chen, Gan Wee; Majid, W. H. Abd. [Low dimensional material research center, Department of physics, Faculty of Science, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2011-03-30T23:59:59.000Z

    Poly(vinylidene fluoride)/ lead zirconate titanate nanocomposite (PVDF/PZT-NPs) were successfully prepared by mixing fine Pb(Zr{sub 0.52}, Ti{sub 0.48})O{sub 3} nanoparticles (PZT-NPs) into a PVDF solution under ultrasonication. The mixture was spin coated onto glass substrate and then annealed at 80 deg. C. X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were used to characterize the structure and properties of the obtained thin-film nanocomposites. The nanocomposites exhibited good dielectric stability over a wide frequency range.

  2. Perturbations for transient acceleration

    SciTech Connect (OSTI)

    Vargas, Cristofher Zuñiga; Zimdahl, Winfried [Universidade Federal do Espírito Santo, Departamento de Física, Av. Fernando Ferrari, 514, Campus de Goiabeiras, CEP 29075-910, Vitória, Espírito Santo (Brazil); Hipólito-Ricaldi, Wiliam S., E-mail: win_unac@hotmail.com, E-mail: hipolito@ceunes.ufes.br, E-mail: winfried.zimdahl@pq.cnpq.br [Universidade Federal do Espírito Santo, Departamento de Ciências Naturais, Grupo de Física Teórica, Rodovia BR 101 Norte, km 60, Campus de São Mateus, CEP 29932-540, São Mateus, Espírito Santo (Brazil)

    2012-04-01T23:59:59.000Z

    According to the standard ?CDM model, the accelerated expansion of the Universe will go on forever. Motivated by recent observational results, we explore the possibility of a finite phase of acceleration which asymptotically approaches another period of decelerated expansion. Extending an earlier study on a corresponding homogeneous and isotropic dynamics, in which interactions between dark matter and dark energy are crucial, the present paper also investigates the dynamics of the matter perturbations both on the Newtonian and General Relativistic (GR) levels and quantifies the potential relevance of perturbations of the dark-energy component. In the background, the model is tested against the Supernova type Ia (SNIa) data of the Constitution set and on the perturbative level against growth rate data, among them those of the WiggleZ survey, and the data of the 2dFGRS project. Our results indicate that a transient phase of accelerated expansion is not excluded by current observations.

  3. Modeling of Field Distribution and Energy Storage in Diphasic Dielectrics

    E-Print Network [OSTI]

    Koledintseva, Marina Y.

    Modeling of Field Distribution and Energy Storage in Diphasic Dielectrics S. K. Patil, M. Y, USA Modeling of electrostatic field distribution and energy storage in diphasic dielectrics containing to the increased energy storage density. For composites with lower volume fractions of high-permittivity inclusions

  4. Dielectric breakdown model for composite materials F. Peruani,1

    E-Print Network [OSTI]

    Peruani, Fernando

    Dielectric breakdown model for composite materials F. Peruani,1 G. Solovey,1 I. M. Irurzun,1,2 E. E on the breakdown of fuse net- works, while others have concentrated on dielectric break- down in networks. Mola,2, * A. Marzocca,1 and J. L. Vicente2 1 Departamento de Fisica, ``Juan Jose´ Giambiagi,'' FCEy

  5. Dielectric function of diluted magnetic semiconductors in the infrared regime

    E-Print Network [OSTI]

    Aguado, R.; Lopez-Sancho, MP; Sinova, Jairo; Brey, L.

    2004-01-01T23:59:59.000Z

    We present a study of the dielectric function of metallic (III,Mn)V diluted magnetic semiconductors in the infrared regime. Our theoretical approach is based on the kinetic exchange model for carrier induced (III,Mn)V ferromagnetism. The dielectric...

  6. Nanostructure multilayer dielectric materials for capacitors and insulators

    DOE Patents [OSTI]

    Barbee, Jr., Troy W. (Palo Alto, CA); Johnson, Gary W. (Livermore, CA)

    1998-04-21T23:59:59.000Z

    A capacitor is formed of at least two metal conductors having a multilayer dielectric and opposite dielectric-conductor interface layers in between. The multilayer dielectric includes many alternating layers of amorphous zirconium oxide (ZrO.sub.2) and alumina (Al.sub.2 O.sub.3). The dielectric-conductor interface layers are engineered for increased voltage breakdown and extended service life. The local interfacial work function is increased to reduce charge injection and thus increase breakdown voltage. Proper material choices can prevent electrochemical reactions and diffusion between the conductor and dielectric. Physical vapor deposition is used to deposit the zirconium oxide (ZrO.sub.2) and alumina (Al.sub.2 O.sub.3) in alternating layers to form a nano-laminate.

  7. Plasma acceleration from radio-frequency discharge in dielectric capillary A. Dunaevskya

    E-Print Network [OSTI]

    .1063/1.2214127 Electric propulsion devices for spacecraft with masses of several tens of kilograms are in increasing, weight, and dimensions. Saturation and thermal load on the magnetic system limit miniaturization had only an efficiency of 6% at 100 W consumed power.4 Pulsing propulsion de- vices such as pulsed

  8. Anomalous optical nonlinearity of dielectric nanodispersions

    SciTech Connect (OSTI)

    Milichko, V A; Dzyuba, V P; Kul'chin, Yurii N

    2013-06-30T23:59:59.000Z

    We present the results of studying the nonlinear optical response of nanodispersions of semiconductor (TiO{sub 2}, ZnO) and dielectric (SiO{sub 2}, Al{sub 2}O{sub 3}) nanoparticles of spherical, spheroidal and flake shape, suspended in polar and nonpolar dielectric matrices (water, isopropanol, polymethylsiloxane and transformer oil) by means of z-scanning in the field of low-intensity visible laser radiation. It is found that, unlike semiconductor nanoparticles and particles of spherical shape, flake-shaped SiO{sub 2} and Al{sub 2}O{sub 3} nanoparticles suspended in nonpolar matrices exhibit nonlinear optical response within the intensity interval from 0 to 500 W cm{sup -2} that vanishes at higher intensities. The diagrams of energy states of the optical electrons in nanoparticles that allow explanation of differences in the nonlinear-optical properties of nanodispersions are proposed. Good agreement between the experimental and theoretical dependences of nonlinear refractive indices and absorption coefficients on the intensity of radiation is observed. (optical nanostructures)

  9. "Z" Facility Dielectric Oil Clean-Up

    SciTech Connect (OSTI)

    Alessandri, Daniel; Bloomquist, Doug; Donovan, Guy; Feltz, Greg; Grelle, Nibby; Guthrie, Doug; Harris, Mark; Horry, Mike; Lockas, Mike; Potter, Jimmy; Pritchard, Chuck; Steedly, Jim

    1999-06-30T23:59:59.000Z

    In August of 1998 the Z facility leaked approximately 150 gallons of deionized water into the dielectric oil of the Energy Storage Section (ESS). After processing the oil to remove existing particulate and free water the dielectric breakdown strength increased from the mid 20kV range to values in excess of 40 kV. 40 kV is above historical operating levels of about 35 kV. This, however, was not enough to allow 90 kV charging of the Marx Generators in the ESS. Further analysis of the oil showed dissolved water at a saturated level (70 - 80 ppm) and some residual particulate contamination smaller than 3 microns. The dissolved water and particulate combination was preventing the 90 kV charging of the Marx Generators in the ESS. After consulting with the oil industry it was determined that nitrogen sparging could be used to remove the dissolved water. Further particulate filtering was also conducted. After approximately 20 hours of sparging the water content in the ESS was reduced to 42 ppm which enabled Marx charging to 90 kV.

  10. Method for preparing dielectric composite materials

    DOE Patents [OSTI]

    Lauf, Robert J.; Anderson, Kimberly K.; Montgomery, Frederick C.; Collins, Jack L.; Felten, John J.

    2004-11-23T23:59:59.000Z

    The invention allows the fabrication of small, dense beads of dielectric materials with selected compositions, which are incorporated into a polymeric matrix for use in capacitors, filters, and the like. A porous, generally spherical bead of hydrous metal oxide containing titanium or zirconium is made by a sol-gel process to form a substantially rigid bead having a generally fine crystallite size and correspondingly finely distributed internal porosity. The resulting gel bead may be washed and hydrothermally reacted with a soluble alkaline earth salt (typically Ba or Sr) at elevated temperature and pressure to convert the bead into a mixed hydrous titanium- or zirconium-alkaline earth oxide while retaining the generally spherical shape. Alternatively, the gel bead may be made by coprecipitation. This mixed oxide bead is then washed, dried and calcined to produce the desired (BaTiO.sub.3, PbTiO.sub.3, SrZrO.sub.3) structure. The sintered beads are incorporated into a selected polymer matrix. The resulting dielectric composite material may be electrically "poled" if desired.

  11. Control of Laser Plasma Based Accelerators up to 1 GeV

    SciTech Connect (OSTI)

    Nakamura, Kei

    2007-12-03T23:59:59.000Z

    This dissertation documents the development of a broadband electron spectrometer (ESM) for GeV class Laser Wakefield Accelerators (LWFA), the production of high quality GeV electron beams (e-beams) for the first time in a LWFA by using a capillary discharge guide (CDG), and a statistical analysis of CDG-LWFAs. An ESM specialized for CDG-LWFAs with an unprecedented wide momentum acceptance, from 0.01 to 1.1 GeV in a single shot, has been developed. Simultaneous measurement of e-beam spectra and output laser properties as well as a large angular acceptance (> {+-} 10 mrad) were realized by employing a slitless scheme. A scintillating screen (LANEX Fast back, LANEX-FB)--camera system allowed faster than 1 Hz operation and evaluation of the spatial properties of e-beams. The design provided sufficient resolution for the whole range of the ESM (below 5% for beams with 2 mrad divergence). The calibration between light yield from LANEX-FB and total charge, and a study on the electron energy dependence (0.071 to 1.23 GeV) of LANEX-FB were performed at the Advanced light source (ALS), Lawrence Berkeley National Laboratory (LBNL). Using this calibration data, the developed ESM provided a charge measurement as well. The production of high quality electron beams up to 1 GeV from a centimeter-scale accelerator was demonstrated. The experiment used a 310 {micro}m diameter gas-filled capillary discharge waveguide that channeled relativistically-intense laser pulses (42 TW, 4.5 x 10{sup 18} W/cm{sup 2}) over 3.3 centimeters of sufficiently low density ({approx_equal} 4.3 x 10{sup 18}/cm{sup 3}) plasma. Also demonstrated was stable self-injection and acceleration at a beam energy of {approx_equal} 0.5 GeV by using a 225 {micro}m diameter capillary. Relativistically-intense laser pulses (12 TW, 1.3 x 10{sup 18}W/cm{sup 2}) were guided over 3.3 centimeters of low density ({approx_equal} 3.5 x 10{sup 18}/cm{sup 3}) plasma in this experiment. A statistical analysis of the CDG-LWFAs performance was carried out. By taking advantage of the high repetition rate experimental system, several thousands of shots were taken in a broad range of the laser and plasma parameters. An analysis program was developed to sort and select the data by specified parameters, and then to evaluate performance statistically. The analysis suggested that the generation of GeV-level beams comes from a highly unstable and regime. By having the plasma density slightly above the threshold density for self injection, (1) the longest dephasing length possible was provided, which led to the generation of high energy e-beams, and (2) the number of electrons injected into the wakefield was kept small, which led to the generation of high quality (low energy spread) e-beams by minimizing the beam loading effect on the wake. The analysis of the stable half-GeV beam regime showed the requirements for stable self injection and acceleration. A small change of discharge delay t{sub dsc}, and input energy E{sub in}, significantly affected performance. The statistical analysis provided information for future optimization, and suggested possible schemes for improvement of the stability and higher quality beam generation. A CDG-LWFA is envisioned as a construction block for the next generation accelerator, enabling significant cost and size reductions.

  12. TOPICS IN THE PHYSICS OF PARTICLE ACCELERATORS

    E-Print Network [OSTI]

    Sessler, A.M.

    2008-01-01T23:59:59.000Z

    their whole lives to accelerator physics. As high energysome appreciation of accelerator physics. We cannot, nor dolectures on basic accelerator physics; then you will hear

  13. Progress on laser plasma accelerators

    SciTech Connect (OSTI)

    Chen, P.

    1986-04-01T23:59:59.000Z

    Several laser plasma accelerator schemes are reviewed, with emphasis on the Plasma Beat Wave Accelerator (PBWA). Theory indicates that a very high acceleration gradient, of order 1 GeV/m, can exist in the plasma wave driven by the beating lasers. Experimental results obtained on the PBWA experiment at UCLA confirms this. Parameters related to the PBWA as an accelerator system are derived, among them issues concerning the efficiency and the laser power and energy requirements are discussed.

  14. Particle Acceleration at Relativistic Shocks

    E-Print Network [OSTI]

    Yves A. Gallant

    2002-01-15T23:59:59.000Z

    I review the current status of Fermi acceleration theory at relativistic shocks. I first discuss the relativistic shock jump conditions, then describe the non-relativistic Fermi mechanism and the differences introduced by relativistic flows. I present numerical calculations of the accelerated particle spectrum, and examine the maximum energy attainable by this process. I briefly consider the minimum energy for Fermi acceleration, and a possible electron pre-acceleration mechanism.

  15. Static dielectric properties of dense ionic fluids

    E-Print Network [OSTI]

    Zarubin, Grigory

    2015-01-01T23:59:59.000Z

    The static dielectric properties of dense ionic fluids, e.g., room temperature ionic liquids (RTILs) and inorganic fused salts, are investigated on different length scales by means of grandcanonical Monte Carlo simulations. A generally applicable scheme is developed which allows one to approximately decompose the electric susceptibility of dense ionic fluids into the orientation and the distortion polarization contribution. It is shown that at long range the well-known plasma-like perfect screening behavior occurs, which corresponds to a diverging distortion susceptibility, whereas at short range orientation polarization dominates, which coincides with that of a dipolar fluid of attached cation-anion pairs. This observation suggests that the recently debated interpretation of RTILs as dilute electrolyte solutions might not be simply a yes-no-question but it might depend on the considered length scale.

  16. Parametric Study of Emerging High Power Accelerator Applications Using Accelerator Systems Model (ASM)

    E-Print Network [OSTI]

    Berwald, D H; Myers, T J; Paulson, C C; Peacock, M A; Piaszczyk, C M; Rathke, J W; Piechowiak, E M

    1996-01-01T23:59:59.000Z

    Parametric Study of Emerging High Power Accelerator Applications Using Accelerator Systems Model (ASM)

  17. Radiation from Accelerated Branes

    E-Print Network [OSTI]

    Mohab Abou-Zeid; Miguel S. Costa

    2000-01-29T23:59:59.000Z

    The radiation emitted by accelerated fundamental strings and D-branes is studied within the linear approximation to the supergravity limit of string theory. We show that scalar, gauge field and gravitational radiation is generically emitted by such branes. In the case where an external scalar field accelerates the branes, we derive a Larmor-type formula for the emitted scalar radiation and study the angular distribution of the outgoing energy flux. The classical radii of the branes are calculated by means of the corresponding Thompson scattering cross sections. Within the linear approximation, the interaction of the external scalar field with the velocity fields of the branes gives a contribution to the observed gauge field and gravitational radiation.

  18. Adaptive control for accelerators

    DOE Patents [OSTI]

    Eaton, Lawrie E. (Los Alamos, NM); Jachim, Stephen P. (Los Alamos, NM); Natter, Eckard F. (Santa Fe, NM)

    1991-01-01T23:59:59.000Z

    An adaptive feedforward control loop is provided to stabilize accelerator beam loading of the radio frequency field in an accelerator cavity during successive pulses of the beam into the cavity. A digital signal processor enables an adaptive algorithm to generate a feedforward error correcting signal functionally determined by the feedback error obtained by a beam pulse loading the cavity after the previous correcting signal was applied to the cavity. Each cavity feedforward correcting signal is successively stored in the digital processor and modified by the feedback error resulting from its application to generate the next feedforward error correcting signal. A feedforward error correcting signal is generated by the digital processor in advance of the beam pulse to enable a composite correcting signal and the beam pulse to arrive concurrently at the cavity.

  19. Accelerator research studies

    SciTech Connect (OSTI)

    Not Available

    1993-01-01T23:59:59.000Z

    The Accelerator Research Studies program at the University of Maryland, sponsored by the Department of Energy under grant number DE-FG05-91ER40642, is currently in the second year of a three-year funding cycle. The program consists of the following three tasks: TASK A, Study of Transport and Longitudinal Compression of Intense, High-Brightness Beams,'' (P.I., M. Reiser); TASK B, Study of Collective Ion Acceleration by Intense Electron Beams and Pseudospark Produced High Brightness Electron Beams,'' (Co-P.I.'s, W.W. Destler, M. Reiser, M.J. Rhee, and C.D. Striffler); TASK C, Study of a Gyroklystron High-Power Microwave Source for Linear Colliders,'' (Co-P.I.'s, V.L. Granatstein, W. Lawson, M. Reiser, and C.D. Striffler). In this report we document the progress that has been made during the past year for each of the three tasks.

  20. Dielectric covered hairpin probe for its application in reactive plasmas

    SciTech Connect (OSTI)

    Gogna, G. S.; Gaman, C.; Turner, M. M. [NCPST, School of Physical Sciences, Dublin City University, Dublin 9 (Ireland); Karkari, S. K. [Institute for Plasma Research Center, Bhat Gandhinagar, Gujarat 382428 (India)

    2012-07-23T23:59:59.000Z

    The hairpin probe is a well known technique for measuring local electron density in low temperature plasmas. In reactive plasmas, the probe characteristics are affected by surface sputtering, contamination, and secondary electron emission. At higher densities, the plasma absorbs the entire electromagnetic energy of hairpin and hence limits the density measurements. These issues can be resolved by covering the hairpin surface with a thin layer of dielectric. In this letter, the dielectric contribution to the probe characteristics is incorporated in a theory which is experimentally verified. The dielectric covering improves the performance of probe and also allows the hairpin tip to survive in reactive plasma where classical electrical probes are easily damaged.

  1. Spherical cloaking using multilayer shells of ordinary dielectrics

    SciTech Connect (OSTI)

    Wang, Xiaohui; Chen, Fang; Semouchkina, Elena, E-mail: esemouch@mtu.edu [Department of Electrical and Computer Engineering, Michigan Technological University, Houghton, MI, 49931 (United States)] [Department of Electrical and Computer Engineering, Michigan Technological University, Houghton, MI, 49931 (United States)

    2013-11-15T23:59:59.000Z

    An approach for spherical cloaking using multilayer ordinary dielectric materials has been developed. The total scattering cross section (TSCS) of the spherical multilayer shell with metallic core was derived based on the Mie theory. The dielectric profile of the shell was optimized to minimize the TSCS of the cloaked target. The specific directions, at which the scattering could be practically eliminated, were detected. The influence of the target size and the dielectric material loss on the cloaking efficiency was analyzed. It was shown that the cloaking efficiency for larger targets could be improved by employing lossy materials in the shell.

  2. Millimeter wave analysis of the dielectric properties of oil shales

    E-Print Network [OSTI]

    John A. Scales; Michael Batzle

    2006-06-06T23:59:59.000Z

    Natural sedimentation processes give rise to fine layers in shales. If these layers alternate between organic-rich and organic-poor sediments, then the contrast in dielectric properties gives rise to an effective birefringence as the presence of hydrocarbons suppresses the dielectric constant of the host rock. We have measured these effects with a quasioptical millimeter wave setup that is rapid and noncontacting. We find that the strength of this birefringence and the overall dielectric permittivity provide two useful diagnostic of the organic content of oil shales.

  3. Linear induction accelerator

    DOE Patents [OSTI]

    Buttram, M.T.; Ginn, J.W.

    1988-06-21T23:59:59.000Z

    A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities. 4 figs.

  4. Accelerating QDP++ using GPUs

    E-Print Network [OSTI]

    Frank Winter

    2011-05-11T23:59:59.000Z

    Graphic Processing Units (GPUs) are getting increasingly important as target architectures in scientific High Performance Computing (HPC). NVIDIA established CUDA as a parallel computing architecture controlling and making use of the compute power of GPUs. CUDA provides sufficient support for C++ language elements to enable the Expression Template (ET) technique in the device memory domain. QDP++ is a C++ vector class library suited for quantum field theory which provides vector data types and expressions and forms the basis of the lattice QCD software suite Chroma. In this work accelerating QDP++ expression evaluation to a GPU was successfully implemented leveraging the ET technique and using Just-In-Time (JIT) compilation. The Portable Expression Template Engine (PETE) and the C API for CUDA kernel arguments were used to build the bridge between host and device memory domains. This provides the possibility to accelerate Chroma routines to a GPU which are typically not subject to special optimisation. As an application example a smearing routine was accelerated to execute on a GPU. A significant speed-up compared to normal CPU execution could be measured.

  5. CESR Test Accelerator

    E-Print Network [OSTI]

    Rubin, David L

    2013-01-01T23:59:59.000Z

    The Cornell Electron Storage Ring (CESR) was reconfigured in 2008 as a test accelerator to investigate the physics of ultra-low emittance damping rings. During the approximately 40 days/year available for dedicated operation as a test accelerator, specialized instrumentation is used to measure growth and mitigation of the electron cloud, emittance growth due to electron cloud, intra-beam scattering, and ions, and single and multi-bunch instabilities generated by collective effects. The flexibility of the CESR guide field optics and the integration of accelerator modeling codes with the control system have made possible an extraordinary range of experiments. Findings at CesrTA with respect to electron cloud effects, emittance tuning techniques, and beam instrumentation for measuring electron cloud, beam sizes, and beam positions are the basis for much of the design of the ILC damping rings as documented in the ILC-Technical Design Report. The program has allowed the Cornell group to cultivate the kind of talen...

  6. Muon Acceleration - RLA and FFAG

    SciTech Connect (OSTI)

    Alex Bogacz

    2011-10-01T23:59:59.000Z

    Various acceleration schemes for muons are presented. The overall goal of the acceleration systems: large acceptance acceleration to 25 GeV and 'beam shaping' can be accomplished by various fixed field accelerators at different stages. They involve three superconducting linacs: a single pass linear Pre-accelerator followed by a pair of multi-pass Recirculating Linear Accelerators (RLA) and finally a non-scaling FFAG ring. The present baseline acceleration scenario has been optimized to take maximum advantage of appropriate acceleration scheme at a given stage. The solenoid based Pre-accelerator offers very large acceptance and facilitates correction of energy gain across the bunch and significant longitudinal compression trough induced synchrotron motion. However, far off-crest acceleration reduces the effective acceleration gradient and adds complexity through the requirement of individual RF phase control for each cavity. The RLAs offer very efficient usage of high gradient superconducting RF and ability to adjust path-length after each linac pass through individual return arcs with uniformly periodic FODO optics suitable for chromatic compensation of emittance dilution with sextupoles. However, they require spreaders/recombiners switchyards at both linac ends and significant total length of the arcs. The non-scaling Fixed Field Alternating Gradient (FFAG) ring combines compactness with very large chromatic acceptance (twice the injection energy) and it allows for large number of passes through the RF (at least eight, possibly as high as 15).

  7. Surface-PlasmonoDielectric-polaritonic devices and systems

    DOE Patents [OSTI]

    Karalis, Aristeidis; Joannopoulos, John; Soljacic, Marin

    2013-06-25T23:59:59.000Z

    There is provided a structure for supporting propagation of surface plasmon polaritons. The structure includes a plasmonic material region and a dielectric material region, disposed adjacent to a selected surface of the plasmonic material region. At least one of the plasmonic material region and the dielectric material region have a dielectric permittivity distribution that is specified as a function of depth through the corresponding material region. This dielectric permittivity distribution is selected to impose prespecified group velocities, v.sub.gj, on a dispersion relation for a surface polaritonic mode of the structure for at least one of a corresponding set of prespecified frequencies, .omega..sub.j, and corresponding set of prespecified wavevectors, where j=1 to N.

  8. Keer electro-optic measurements in liquid dielectrics

    E-Print Network [OSTI]

    Zhang, Xuewei

    2014-01-01T23:59:59.000Z

    Kerr electro-optic technique has been used to measure the electric field distribution in high voltage stressed dielectric liquids, where the difference between refractive indices for light polarized parallel and perpendicular ...

  9. Quantum mechanical theory of dynamic nuclear polarization in solid dielectrics

    E-Print Network [OSTI]

    Hu, Kan-Nian

    Microwave driven dynamic nuclear polarization (DNP) is a process in which the large polarization present in an electron spin reservoir is transferred to nuclei, thereby enhancing NMR signal intensities. In solid dielectrics ...

  10. Stochastic and deterministic causes of streamer branching in liquid dielectrics

    E-Print Network [OSTI]

    Jadidian, Jouya

    Streamer branching in liquid dielectrics is driven by stochastic and deterministic factors. The presence of stochastic causes of streamer branching such as inhomogeneities inherited from noisy initial states, impurities, ...

  11. THZ TRANSMISSION SPECTROSCOPY APPLIED TO DIELECTRICS AND MICROWAVE CERAMICS

    E-Print Network [OSTI]

    Ku?el, Petr

    and unambiguous evaluation of the dielectric function are also discussed. Keywords Terahertz pulses; far infrared-optic sampling technique[14] with a 1 mm thick high-resistivity ZnTe sensor crystal was employed

  12. Materials for freeform fabrication of GHz tunable dielectric photonic crystals.

    SciTech Connect (OSTI)

    Niehaus, Michael Keith; Lewis, Jennifer A. (University of Illinois, Urbana, IL); Smay, James Earl; Clem, Paul Gilbert; Lin, Shawn-Yu; Cesarano, Joseph, III (,; ); Carroll, James F.

    2003-01-01T23:59:59.000Z

    Photonic crystals are of interest for GHz transmission applications, including rapid switching, GHz filters, and phased-array technology. 3D fabrication by Robocasting enables moldless printing of high solid loading slurries into structures such as the ''woodpile'' structures used to fabricate dielectric photonic band gap crystals. In this work, tunable dielectric materials were developed and printed into woodpile structures via solid freeform fabrication (SFF) toward demonstration of tunable photonic crystals. Barium strontium titanate ceramics possess interesting electrical properties including high permittivity, low loss, and high tunability. This paper discusses the processing route and dielectric characterization of (BaxSr1-XTiO3):MgO ceramic composites, toward fabrication of tunable dielectric photonic band gap crystals.

  13. Surface flashover breakdown mechanisms on liquid immersed dielectrics

    E-Print Network [OSTI]

    Jadidian, Jouya

    Flashover formation and expansion mechanisms on the surfaces of different dielectrics immersed in transformer oil have been numerically analyzed. Streamers emanating from a needle electrode tend to transform to surface ...

  14. affect dielectric membrane: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    how relaxation dynamics of a poly-vinyl-acetate ultra-thin film is influenced by inorganic nano-inclusions of a layered silicate (montmorillonite). Dielectric loss spectra are...

  15. Near field radiative heat transfer between two nonlocal dielectrics

    E-Print Network [OSTI]

    Singer, F; Joulain, Karl

    2015-01-01T23:59:59.000Z

    We explore in the present work the near-field radiative heat transfer between two semi-infinite parallel nonlocal dielectric planes by means of fluctuational electrodynamics. We use atheory for the nonlocal dielectric permittivityfunction proposed byHalevi and Fuchs. This theory has the advantage to includedifferent models performed in the literature. According to this theory, the nonlocal dielectric function is described by a Lorenz-Drude like single oscillator model, in which the spatial dispersion effects are represented by an additional term depending on the square of the total wavevector k. The theory takes into account the scattering of the electromagneticexcitation at the surface of the dielectric material, which leads to the need of additional boundary conditions in order to solve Maxwell's equations and treat the electromagnetic transmission problem. The additional boundary conditions appear as additional surface scattering parameters in the expressions of the surface impedances. It is shown that the...

  16. Evaluation of unsaturated fluorocarbons for dielectric Etch applications

    E-Print Network [OSTI]

    Chatterjee, Ritwik, 1974-

    2003-01-01T23:59:59.000Z

    The semiconductor industry is currently faced with the problem of the use and emissions of strong global warming compounds, known as perfluorocompounds (PFCs) for dielectric etch applications. The release of global warming ...

  17. Silica aerogel: An intrinsically low dielectric constant material

    SciTech Connect (OSTI)

    Hrubesh, L.W.

    1995-04-01T23:59:59.000Z

    Silica aerogels are highly porous solids having unique morphologies in wavelength of visible which both the pores and particles have sizes less than the wavelength of visible light. This fine nanostructure modifies the normal transport mechanisms within aerogels and endows them with a variety of exceptional physical properties. For example, aerogels have the lowest measured thermal conductivity and dielectric constant for any solid material. The intrinsically low dielectric properties of silica aerogels are the direct result of the extremely high achievable porosities, which are controllable over a range from 75% to more than 99.8 %, and which result in measured dielectric constants from 2.0 to less than 1.01. This paper discusses the synthesis of silica aerogels, processing them as thin films, and characterizing their dielectric properties. Existing data and other physical characteristics of bulk aerogels (e.g., thermal stablity, thermal expansion, moisture adsorption, modulus, dielectric strength, etc.), which are useful for evaluating them as potential dielectrics for microelectronics, are also given.

  18. Charge regulation and local dielectric function in planar polyelectrolyte brushes

    E-Print Network [OSTI]

    Rajeev Kumar; Bobby G. Sumpter; S. Michael Kilbey II

    2012-06-20T23:59:59.000Z

    Understanding the effect of inhomogeneity on the charge regulation and dielectric properties, and how it depends on the conformational characteristics of the macromolecules is a long-standing problem. In order to address this problem, we have developed a field-theory to study charge regulation and local dielectric function in planar polyelectrolyte brushes. The theory is used to study a polyacid brush, which is comprised of chains end-grafted at the solid-fluid interface, in equilibrium with a bulk solution containing monovalent salt ions, solvent molecules and pH controlling acid. In particular, we focus on the effects of the concentration of added salt and pH of the bulk in determining the local charge and dielectric function. Our theoretical investigations reveal that the dipole moment of the ion-pairs formed as a result of counterion adsorption on the chain backbones play a key role in affecting the local dielectric function. For polyelectrolytes made of monomers having dipole moments lower than the solvent molecules, dielectric decrement is predicted inside the brush region. However, the formation of ion-pairs (due to adsorption of counterions coming from the dissociation of added salt) more polar than the solvent molecules is shown to increase the magnitude of the dielectric function with respect to its bulk value. Furthermore, an increase in the bulk salt concentration is shown to increase the local charge inside the brush region.

  19. APT accelerator. Topical report

    SciTech Connect (OSTI)

    Lawrence, G.; Rusthoi, D. [comp.] [ed.

    1995-03-01T23:59:59.000Z

    The Accelerator Production of Tritium (APT) project, sponsored by Department of Energy Defense Programs (DOE/DP), involves the preconceptual design of an accelerator system to produce tritium for the nation`s stockpile of nuclear weapons. Tritium is an isotope of hydrogen used in nuclear weapons, and must be replenished because of radioactive decay (its half-life is approximately 12 years). Because the annual production requirements for tritium has greatly decreased since the end of the Cold War, an alternative approach to reactors for tritium production, based on a linear accelerator, is now being seriously considered. The annual tritium requirement at the time this study was undertaken (1992-1993) was 3/8 that of the 1988 goal, usually stated as 3/8-Goal. Continued reduction in the number of weapons in the stockpile has led to a revised (lower) production requirement today (March, 1995). The production requirement needed to maintain the reduced stockpile, as stated in the recent Nuclear Posture Review (summer 1994) is approximately 3/16-Goal, half the previous level. The Nuclear Posture Review also requires that the production plant be designed to accomodate a production increase (surge) to 3/8-Goal capability within five years, to allow recovery from a possible extended outage of the tritium plant. A multi-laboratory team, collaborating with several industrial partners, has developed a preconceptual APT design for the 3/8-Goal, operating at 75% capacity. The team has presented APT as a promising alternative to the reactor concepts proposed for Complex-21. Given the requirements of a reduced weapons stockpile, APT offers both significant safety, environmental, and production-fexibility advantages in comparison with reactor systems, and the prospect of successful development in time to meet the US defense requirements of the 21st Century.

  20. Particle Acceleration by MHD Turbulence

    E-Print Network [OSTI]

    Jungyeon Cho; A. Lazarian

    2005-10-21T23:59:59.000Z

    Recent advances in understanding of magnetohydrodynamic (MHD) turbulence call for revisions in the picture of particle acceleration. We make use of the recently established scaling of slow and fast MHD modes in strong and weak MHD turbulence to provide a systematic study of particle acceleration in magnetic pressure (low-$\\beta$) and gaseous pressure (high-$\\beta$) dominated plasmas. We consider the acceleration by large scale compressions in both slow and fast particle diffusion limits. We compare the results with the acceleration rate that arises from resonance scattering and Transit-Time Damping (TTD). We establish that fast modes accelerate particles more efficiently than slow modes. We find that particle acceleration by pitch-angle scattering and TTD dominates acceleration by slow or fast modes when the spatial diffusion rate is small. When the rate of spatial diffusion of particles is high, we establish an enhancement of the efficiency of particle acceleration by slow and fast modes in weak turbulence. We show that highly supersonic turbulence is an efficient agent for particle acceleration. We find that even incompressible turbulence can accelerate particles on the scales comparable with the particle mean free path.

  1. Accelerators AND Beams

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041cloth DocumentationProducts (VAP) VAP7-0973 1 Introduction In theACME -Toggle FermilabAccelerators

  2. Thomas Precession by Uniform Acceleration

    E-Print Network [OSTI]

    Miroslav Pardy

    2014-12-09T23:59:59.000Z

    We determine the nonlinear transformations between coordinate systems which are mutually in a constant symmetrical accelerated motion. The maximal acceleration limit follows from the kinematical origin and it is an analogue of the maximal velocity in special relativity. We derive the dependence of mass, length, time, Doppler effect, Cherenkov effect and transition radiation angle on acceleration as an analogue phenomena in special theory of relativity. The last application of our method is the Thomas precession by uniform acceleration with the possible role in the modern physics and cosmology. The comparison of derived results with other relativistic methods is necessary.

  3. Nuclear Physics: Archived Talks - Accelerator

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Free Electron Laser (FEL) Medical Imaging Physics Topics Campaigns Meetings Recent Talks Archived Talks Accelerator Hall A Hall B Hall C 12 GeV Upgrade Experimental Techniques...

  4. Compact accelerator for medical therapy

    DOE Patents [OSTI]

    Caporaso, George J.; Chen, Yu-Jiuan; Hawkins, Steven A.; Sampayan, Stephen E.; Paul, Arthur C.

    2010-05-04T23:59:59.000Z

    A compact accelerator system having an integrated particle generator-linear accelerator with a compact, small-scale construction capable of producing an energetic (.about.70-250 MeV) proton beam or other nuclei and transporting the beam direction to a medical therapy patient without the need for bending magnets or other hardware often required for remote beam transport. The integrated particle generator-accelerator is actuable as a unitary body on a support structure to enable scanning of a particle beam by direction actuation of the particle generator-accelerator.

  5. High field gradient particle accelerator

    DOE Patents [OSTI]

    Nation, J.A.; Greenwald, S.

    1989-05-30T23:59:59.000Z

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications is disclosed. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle. 10 figs.

  6. High field gradient particle accelerator

    DOE Patents [OSTI]

    Nation, John A. (Ithaca, NY); Greenwald, Shlomo (Haifa, IL)

    1989-01-01T23:59:59.000Z

    A high electric field gradient electron accelerator utilizing short duration, microwave radiation, and capable of operating at high field gradients for high energy physics applications or at reduced electric field gradients for high average current intermediate energy accelerator applications. Particles are accelerated in a smooth bore, periodic undulating waveguide, wherein the period is so selected that the particles slip an integral number of cycles of the r.f. wave every period of the structure. This phase step of the particles produces substantially continuous acceleration in a traveling wave without transverse magnetic or other guide means for the particle.

  7. Thomas Precession by Uniform Acceleration

    E-Print Network [OSTI]

    Pardy, Miroslav

    2015-01-01T23:59:59.000Z

    We determine the nonlinear transformations between coordinate systems which are mutually in a constant symmetrical accelerated motion. The maximal acceleration limit follows from the kinematical origin and it is an analogue of the maximal velocity in special relativity. We derive the dependence of mass, length, time, Doppler effect, Cherenkov effect and transition radiation angle on acceleration as an analogue phenomena in special theory of relativity. The last application of our method is the Thomas precession by uniform acceleration with the possible role in the modern physics and cosmology. The comparison of derived results with other relativistic methods is necessary.

  8. Lab Breakthrough: Fermilab Accelerator Technology

    Broader source: Energy.gov [DOE]

    Fermilab scientists developed techniques to retrofit some of the 30,000 particle accelerators in use around the world to make them more efficient and powerful.

  9. COMPASS, the COMmunity Petascale project for Accelerator Science and Simulation, a board computational accelerator physics initiative

    E-Print Network [OSTI]

    Cary, J.R.

    2008-01-01T23:59:59.000Z

    a broad computational accelerator physics initiative † J Rbroad computational accelerator physics initiative J R Caryand future to the accelerator physics community of the

  10. THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY The Radiological Research Accelerator Facility

    E-Print Network [OSTI]

    THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY 71 The Radiological Research Accelerator Facility the irradiated cells. Both the microbeam and the track segment facilities continue to be utilized in various investigations of this phenomenon. The single- particle microbeam facility provides precise control of the number

  11. THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY The Radiological Research Accelerator Facility

    E-Print Network [OSTI]

    THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY 1 The Radiological Research Accelerator Facility for Radiological Research (CRR). Using the mi- crobeam facility, 10% of the cells were irradiated through particle beam as well as the first fo- cused microbeam in the new microbeam facility. · Another significant

  12. The Radiological Research Accelerator THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY

    E-Print Network [OSTI]

    The Radiological Research Accelerator Facility #12;84 THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY Director: David J. Brenner, Ph.D., D.Sc., Manager: Stephen A. Marino, M.S. An NIH SupportedV/µm 4 He ions using the microbeam facility (Exp. 73) also continued. The transformation frequency

  13. Muon Collider Progress: Accelerators

    E-Print Network [OSTI]

    Michael S. Zisman

    2011-09-14T23:59:59.000Z

    A muon collider would be a powerful tool for exploring the energy-frontier with leptons, and would complement the studies now under way at the LHC. Such a device would offer several important benefits. Muons, like electrons, are point particles so the full center-of-mass energy is available for particle production. Moreover, on account of their higher mass, muons give rise to very little synchrotron radiation and produce very little beamstrahlung. The first feature permits the use of a circular collider that can make efficient use of the expensive rf system and whose footprint is compatible with an existing laboratory site. The second feature leads to a relatively narrow energy spread at the collision point. Designing an accelerator complex for a muon collider is a challenging task. Firstly, the muons are produced as a tertiary beam, so a high-power proton beam and a target that can withstand it are needed to provide the required luminosity of ~1 \\times 10^34 cm^-2s^-1. Secondly, the beam is initially produced with a large 6D phase space, which necessitates a scheme for reducing the muon beam emittance ("cooling"). Finally, the muon has a short lifetime so all beam manipulations must be done very rapidly. The Muon Accelerator Program, led by Fermilab and including a number of U.S. national laboratories and universities, has undertaken design and R&D activities aimed toward the eventual construction of a muon collider. Design features of such a facility and the supporting R&D program are described.

  14. Enhanced Optomechanical Levitation of Minimally Supported Dielectrics

    E-Print Network [OSTI]

    Tina Müller; Christoph Reinhardt; Jack C. Sankey

    2015-04-30T23:59:59.000Z

    Optically levitated mechanical sensors promise isolation from thermal noise far beyond what is possible using flexible materials alone. One way to access this potential is to apply a strong optical trap to a minimally supported mechanical element, thereby increasing its quality factor $Q_m$. Current schemes, however, require prohibitively high laser power ($\\sim10$ W), and the $Q_m$ enhancement is ultimately limited to a factor of $\\sim$ 50 by hybridization between the trapped mode and the dissipative modes of the supporting structure. Here we propose a levitation scheme taking full advantage of an optical resonator to reduce the circulating power requirements by many orders of magnitude. Applying this scheme to the case of a dielectric disk in a Fabry-Perot cavity, we find a tilt-based tuning mechanism for optimizing both center-of-mass and torsional mode traps. Notably, the two modes are trapped with comparable efficiency, and we estimate that a 10-micron-diameter, 100-nm-thick Si disc could be trapped to a frequency of $\\sim$ 10 MHz with only $30$ mW circulating in a cavity of (modest) finesse 1500. Finally, we simulate the effect such a strong trap would have on a realistic doubly-tethered disc. Of central importance, we find torsional motion is comparatively immune to $Q_m$-limiting hybridization, allowing a $Q_m$ enhancement factor of $\\sim$ 1500. This opens the possibility of realizing a laser-tuned 10 MHz mechanical system with a quality factor of order a billion.

  15. Laser acceleration of ion beams

    E-Print Network [OSTI]

    I. A. Egorova; A. V. Filatov; A. V. Prozorkevich; S. A. Smolyansky; D. B. Blaschke; M. Chubaryan

    2007-02-01T23:59:59.000Z

    We consider methods of charged particle acceleration by means of high-intensity lasers. As an application we discuss a laser booster for heavy ion beams provided, e.g. by the Dubna nuclotron. Simple estimates show that a cascade of crossed laser beams would be necessary to provide additional acceleration to gold ions of the order of GeV/nucleon.

  16. I Investigation of Pellet Acceleration

    E-Print Network [OSTI]

    I Investigation of Pellet Acceleration by an Arc heated Gas Gun An Interim Report INVESTIGATION OP PELLET ACCELERATION BY AN ARC HEATED GAS GUN* An Interim Report on the Investigations carried, and K.-V. Weisberg Abstract. Deep penetration of pellets into the JET plasma may prove to be a useful

  17. SBA Growth Accelerator Fund Competition

    Broader source: Energy.gov [DOE]

    The U.S. Small Business Administration (SBA) is accepting applications for the Growth Accelerator Fund Competition to identify the nation's innovative accelerators and similar organizations and award them cash prizes they may use to fund their operations costs and allow them to bring startup competitions to scale and new ideas to life.

  18. A Low-Charge, Hard X-Ray FEL Driven with an X-band Injector and Accelerator

    SciTech Connect (OSTI)

    Sun, Yipeng; Adolphsen, Chris; Limborg-Deprey, Cecile; Raubenheimer, Tor; Wu, Juhao; /SLAC

    2012-02-17T23:59:59.000Z

    After the successful operation of FLASH (Free-Electron Laser in Hamburg) and LCLS (Linac Coherent Light Source), soft and hard X-ray Free Electron Lasers (FELs) are being built, designed or proposed at many accelerator laboratories. Acceleration employing lower frequency RF cavities, ranging from L-band to C-band, is usually adopted in these designs. In the first stage bunch compression, higher-frequency harmonic RF system is employed to linearize the beam's longitudinal phase space, which is nonlinearly chirped during the lower frequency RF acceleration process. In this paper, a hard X-ray FEL design using an all X-band accelerator at 11.424 GHz (from photo-cathode RF gun to linac end) is presented, without the assistance of any harmonic RF linearization. It achieves LCLS-like performance at low charge using X-band linac drivers, which is more versatile, efficient and compact than ones using S-band or C-band rf technology. It employs initially 42 microns long (RMS), low charge (10 pC) electron bunches from an X-band photoinjector. An overall bunch compression ratio of roughly 100 times is proposed in a two stage bunch compressor system. The start-to-end macro-particle 3-D simulation employing several computer codes is presented in this paper, where space charge, wakefields, incoherent and coherent synchrotron radiation (ISR and CSR) effects are included. Employing an undulator with a short period of 1.5 cm, a Genesis FEL simulation shows successful lasing at a wavelength of 0.15 nm with a pulse length of 2 fs and a power saturation length as short as 20 meters, which is equivalent to LCLS low charge mode. Its overall length of both accelerators and undulators is 180 meters (much shorter than the effective LCLS overall length of 1230 meters, including an accelerator length of 1100 meters and an undulator length of 130 meters), which makes it possible to be built in places where only limited space is available.

  19. Low-Charge, Hard X-Ray Free Electron Laser Driven with an X-Band Injector and Accelerator

    SciTech Connect (OSTI)

    Sun, Yipeng; Adolphsen, Chris; Limborg-Deprey, Cecile; Raubenheimer, Tor; Wu, Juhao; /SLAC

    2012-04-17T23:59:59.000Z

    After the successful operation of the Free Electron Laser in Hamburg (FLASH) and the Linac Coherent Light Source (LCLS), soft and hard x-ray free electron lasers (FELs) are being built, designed, or proposed at many accelerator laboratories. Acceleration employing lower frequency rf cavities, ranging from L-band to C-band, is usually adopted in these designs. In the first stage bunch compression, higher-frequency harmonic rf system is employed to linearize the beam's longitudinal phase space, which is nonlinearly chirped during the lower frequency rf acceleration process. In this paper, a hard x-ray FEL design using an all X-band accelerator at 11.424 GHz (from photocathode rf gun to linac end) is presented, without the assistance of any harmonic rf linearization. It achieves LCLS-like performance at low charge using X-band linac drivers, which is more versatile, efficient, and compact than ones using S-band or C-band rf technology. It employs initially 42 microns long (rms), low-charge (10 pC) electron bunches from an X-band photoinjector. An overall bunch compression ratio of roughly 100 times is proposed in a two stage bunch compressor system. The start-to-end macroparticle 3D simulation employing several computer codes is presented in this paper, where space charge, wakefields, and incoherent and coherent synchrotron radiation effects are included. Employing an undulator with a short period of 1.5 cm, a Genesis FEL simulation shows successful lasing at a wavelength of 0.15 nm with a pulse length of 2 fs and a power saturation length as short as 20 meters, which is equivalent to LCLS low-charge mode. Its overall length of both accelerators and undulators is 180 meters (much shorter than the effective LCLS overall length of 1230 meters, including an accelerator length of 1100 meters and an undulator length of 130 meters), which makes it possible to be built in places where only limited space is available.

  20. Particle Acceleration in Astrophysical Sources

    E-Print Network [OSTI]

    Amato, Elena

    2015-01-01T23:59:59.000Z

    Astrophysical sources are extremely efficient accelerators. Some sources emit photons up to multi-TeV energies, a signature of the presence, within them, of particles with energies much higher than those achievable with the largest accelerators on Earth. Even more compelling evidence comes from the study of Cosmic Rays, charged relativistic particles that reach the Earth with incredibly high energies: at the highest energy end of their spectrum, these subatomic particles are carrying a macroscopic energy, up to a few Joules. Here I will address the best candidate sources and mechanisms as cosmic particle accelerators. I will mainly focus on Galactic sources such as Supernova Remnants and Pulsar Wind Nebulae, which being close and bright, are the best studied among astrophysical accelerators. These sources are held responsible for most of the energy that is put in relativistic particles in the Universe, but they are not thought to accelerate particles up to the highest individual energies, $\\approx 10^{20}$ eV...

  1. Dielectric profile variations in high-index-contrast waveguides, coupled mode theory, and perturbation expansions

    E-Print Network [OSTI]

    Dielectric profile variations in high-index-contrast waveguides, coupled mode theory high dielec- tric contrast profiles standard perturbation formulations fails when applied for the high-index-contrast discontinuous dielectric profiles. Among others, our formulation allows

  2. EFFECT OF SALINITY ON THE DIELECTRIC PROPERTIES OF GEOLOGICAL MATERIALS : IMPLICATION FOR SOIL

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    . Dielectric mixing models were first calibrated by means of experimental measurements before being used of SAR data (AIRSAR, PALSAR). Keywords- Earth, evaporites, dielectric mixing model, IEM, Mars, polarimetry, radar backscattering, salinity, SAR, soil moisture. I. INTRODUCTION The measurement of soil

  3. Dielectric and electrical conduction behavior of carbon paste electrochemical electrodes, with

    E-Print Network [OSTI]

    Chung, Deborah D.L.

    and supercapacitors; strong dielectric properties are attractive for supercapacitors but not batteries. Exfoliated graphite provides handleability and excellent volumetric and interfacial conductivities. It gives low carbon dielectric constant, but contributes to the interfacial capacitances. Activated graphite

  4. Broadband Dielectric Spectroscopy on Glass-Forming Propylene Carbonate

    E-Print Network [OSTI]

    U. Schneider; P. Lunkenheimer; R. Brand; A. Loidl

    1998-12-14T23:59:59.000Z

    Dielectric spectroscopy covering more than 18 decades of frequency has been performed on propylene carbonate in its liquid and supercooled-liquid state. Using quasi-optic submillimeter and far-infrared spectroscopy the dielectric response was investigated up to frequencies well into the microscopic regime. We discuss the alpha-process whose characteristic timescale is observed over 14 decades of frequency and the excess wing showing up at frequencies some three decades above the peak frequency. Special attention is given to the high-frequency response of the dielectric loss in the crossover regime between alpha-peak and boson-peak. Similar to our previous results in other glass forming materials we find evidence for additional processes in the crossover regime. However, significant differences concerning the spectral form at high frequencies are found. We compare our results to the susceptibilities obtained from light scattering and to the predictions of various models of the glass transition.

  5. Velocity bunching in travelling wave accelerator with low acceleration gradient

    E-Print Network [OSTI]

    Huang, Rui-Xuan; Li, Wei-Wei; Jia, Qi-Ka

    2013-01-01T23:59:59.000Z

    We present the analytical and simulated results concerning the influences of the acceleration gradient in the velocity bunching process, which is a bunch compression scheme that uses a traveling wave accelerating structure as a compressor. Our study shows that the bunch compression application with low acceleration gradient is more tolerant to phase jitter and more successful to obtain compressed electron beam with symmetrical longitudinal distribution and low energy spread. We also present a transverse emittance compensation scheme to compensate the emittance growth caused by the increasing of the space charge force in the compressing process that is easy to be adjusted for different compressing factors.

  6. Electron beam accelerator with magnetic pulse compression and accelerator switching

    DOE Patents [OSTI]

    Birx, D.L.; Reginato, L.L.

    1984-03-22T23:59:59.000Z

    An electron beam accelerator is described comprising an electron beam generator-injector to produce a focused beam of greater than or equal to .1 MeV energy electrons; a plurality of substantially identical, aligned accelerator modules to sequentially receive and increase the kinetic energies of the beam electron by about .1-1 MeV per module. Each accelerator module includes a pulse-forming network that delivers a voltage pulse to the module of substantially .1-1 MeV maximum energy over a time duration of less than or equal to 1 ..mu..sec.

  7. Dielectric supported radio-frequency cavities

    DOE Patents [OSTI]

    Yu, David U. L. (Rancho Palos Verdes, CA); Lee, Terry G. (Cupertino, CA)

    2000-01-01T23:59:59.000Z

    A device which improves the electrical and thermomechanical performance of an RF cavity, for example, in a disk-loaded accelerating structure. A washer made of polycrystalline diamond is brazed in the middle to a copper disk washer and at the outer edge to the plane wave transformer tank wall, thus dissipating heat from the copper disk to the outer tank wall while at the same time providing strong mechanical support to the metal disk. The washer structure eliminates the longitudinal connecting rods and cooling channels used in the currently available cavities, and as a result minimizes problems such as shunt impedance degradation and field distortion in the plane wave transformer, and mechanical deflection and uneven cooling of the disk assembly.

  8. E-Print Network 3.0 - active dielectric microstructures Sample...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Plasma Actuators for Active Aerodynamic Flow Control," AIAA... Results Using Aerogels and Ferroelectrics for Dielectric Barrier Discharge Actuators Ryan Durscher......

  9. E-Print Network 3.0 - atmospheric dielectric barrier Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Force Measurement Techniques and Preliminary Results Summary: Results Using Aerogels and Ferroelectrics for Dielectric Barrier Discharge Actuators Ryan Durscher......

  10. Radiological Research Accelerator Facility Service Request Form

    E-Print Network [OSTI]

    Radiological Research Accelerator Facility Service Request Form National Institute of Biomedical Imaging and Bioengineering Radiological Research Accelerator Facility Service request form Estimate when(s) to control for this experiment (if more than one, please prioritize): Radiological Research Accelerator

  11. FPGA Acceleration of Discrete Molecular Dynamics Simulation

    E-Print Network [OSTI]

    Herbordt, Martin

    ' & $ % FPGA Acceleration of Discrete Molecular Dynamics Simulation Joshua Model Thesis submitted UNIVERSITY COLLEGE OF ENGINEERING Thesis FPGA Acceleration of Discrete Molecular Dynamics Simulation Acceleration of Discrete Molecular Dynamics Simulation Joshua Model ABSTRACT Molecular dynamics simulation

  12. TOPICS IN THE PHYSICS OF PARTICLE ACCELERATORS

    E-Print Network [OSTI]

    Sessler, A.M.

    2008-01-01T23:59:59.000Z

    IN THE PHYSICS OF PARTICLE ACCELERATORS A.M. Sessler TWO-IN THE PHYSICS OF PARTICLE ACCELERATORS Andrew M. SesslerBruck, "Circular Particle Accelerators," PUF, Paris (1966).

  13. Cathode fall measurement in a dielectric barrier discharge in helium

    SciTech Connect (OSTI)

    Hao, Yanpeng; Zheng, Bin; Liu, Yaoge [School of Electric Power, South China University of Technology, Guangzhou 510640 (China)] [School of Electric Power, South China University of Technology, Guangzhou 510640 (China)

    2013-11-15T23:59:59.000Z

    A method based on the “zero-length voltage” extrapolation is proposed to measure cathode fall in a dielectric barrier discharge. Starting, stable, and discharge-maintaining voltages were measured to obtain the extrapolation zero-length voltage. Under our experimental conditions, the “zero-length voltage” gave a cathode fall of about 185 V. Based on the known thickness of the cathode fall region, the spatial distribution of the electric field strength in dielectric barrier discharge in atmospheric helium is determined. The strong cathode fall with a maximum field value of approximately 9.25 kV/cm was typical for the glow mode of the discharge.

  14. Probing the membrane potential of living cells by dielectric spectroscopy

    E-Print Network [OSTI]

    Corina Bot; Camelia Prodan

    2008-12-17T23:59:59.000Z

    In this paper we demonstrate a quantitative way to measure the membrane potential of live cells by dielectric spectroscopy. We also show that the values of the membrane potential obtained using our technique are in good agreement with those obtained using traditional methods-voltage sensitive dyes. The membrane potential is determined by fitting the experimental dielectric dispersion curves with the dispersion curves obtain from a theoretical model. Variations in the membrane potential were induced by modifying the concentration of potassium chloride in the solution of the cell suspension in the presence of valinomycin. For exemplification of the method, E. coli were chosen for our experiments.

  15. RFQ accelerator tuning system

    DOE Patents [OSTI]

    Bolie, Victor W. (Albuquerque, NM)

    1990-01-01T23:59:59.000Z

    A cooling system is provided for maintaining a preselected operating temperature in a device, which may be an RFQ accelerator, having a variable heat removal requirement, by circulating a cooling fluid through a cooling system remote from the device. Internal sensors in the device enable an estimated error signal to be generated from parameters which are indicative of the heat removal requirement from the device. Sensors are provided at predetermined locations in the cooling system for outputting operational temperature signals. Analog and digital computers define a control signal functionally related to the temperature signals and the estimated error signal, where the control signal is defined effective to return the device to the preselected operating temperature in a stable manner. The cooling system includes a first heat sink responsive to a first portion of the control signal to remove heat from a major portion of the circulating fluid. A second heat sink is responsive to a second portion of the control signal to remove heat from a minor portion of the circulating fluid. The cooled major and minor portions of the circulating fluid are mixed in response to a mixing portion of the control signal, which is effective to proportion the major and minor portions of the circulating fluid to establish a mixed fluid temperature which is effective to define the preselected operating temperature for the remote device. In an RFQ environment the stable temperature control enables the resonant frequency of the device to be maintained at substantially a predetermined value during transient operations.

  16. RFQ accelerator tuning system

    DOE Patents [OSTI]

    Bolie, V.W.

    1990-07-03T23:59:59.000Z

    A cooling system is provided for maintaining a preselected operating temperature in a device, which may be an RFQ accelerator, having a variable heat removal requirement, by circulating a cooling fluid through a cooling system remote from the device. Internal sensors in the device enable an estimated error signal to be generated from parameters which are indicative of the heat removal requirement from the device. Sensors are provided at predetermined locations in the cooling system for outputting operational temperature signals. Analog and digital computers define a control signal functionally related to the temperature signals and the estimated error signal, where the control signal is defined effective to return the device to the preselected operating temperature in a stable manner. The cooling system includes a first heat sink responsive to a first portion of the control signal to remove heat from a major portion of the circulating fluid. A second heat sink is responsive to a second portion of the control signal to remove heat from a minor portion of the circulating fluid. The cooled major and minor portions of the circulating fluid are mixed in response to a mixing portion of the control signal, which is effective to proportion the major and minor portions of the circulating fluid to establish a mixed fluid temperature which is effective to define the preselected operating temperature for the remote device. In an RFQ environment the stable temperature control enables the resonant frequency of the device to be maintained at substantially a predetermined value during transient operations. 3 figs.

  17. Dependence of exciton transition energy of single-walled carbon nanotubes on surrounding dielectric materials

    E-Print Network [OSTI]

    Maruyama, Shigeo

    Dependence of exciton transition energy of single-walled carbon nanotubes on surrounding dielectric 11, 2007) We theoretically investigate the dependence of exciton transition energies on dielectric transition energy dependence on dielectric constant of various surrounding materials. PACS numbers: 78.67.Ch

  18. Influence of stoichiometry on the dielectric properties of sputtered strontium titanate thin films

    E-Print Network [OSTI]

    York, Robert A.

    Influence of stoichiometry on the dielectric properties of sputtered strontium titanate thin films.1063/1.1598274 INTRODUCTION SrTiO3 thin films have been widely studied for their high dielectric constants and potential temperature superconductors. The dielectric permittivity of SrTiO3 thin films is significantly smaller than

  19. HIGH-THROUGHPUT CELL AND PARTICLE CHARACTERIZATION USING ISO-DIELECTRIC

    E-Print Network [OSTI]

    Voldman, Joel

    HIGH-THROUGHPUT CELL AND PARTICLE CHARACTERIZATION USING ISO-DIELECTRIC SEPARATION Michael D. Vahey conductivity. Using a re- cently developed separation method - iso-dielectric separation (IDS) - we character for developing new screens. THEORY We recently developed a separa- tion method, called iso-dielectric sepa

  20. Experimental test accelerator (ETA) II

    SciTech Connect (OSTI)

    Fessenden, T.J.; Atchison, W.L.; Birx, D.L.

    1981-03-06T23:59:59.000Z

    The Experimental Test Accelerator (ETA) is designed to produce a 10 kAmp electron beam at an energy of 4.5 MeV in 40 nsec pulses at an average rate of 2 pps. The accelerator also operates in bursts of 5 pulses spaced by as little as one millisec at an average rate of 5 pps. The machine is currently operating near 80% of its design values and has accumulated over 2.5 million pulses - mostly at a rate of one pps. The plasma cathode electron source, the remainder of the accelerator, and the operating characteristics of the machine are discussed.

  1. Cosmic Particle Acceleration: Basic Issues

    E-Print Network [OSTI]

    T. W. Jones

    2000-12-22T23:59:59.000Z

    Cosmic-rays are ubiquitous, but their origins are surprisingly difficult to understand. A review is presented of some of the basic issues common to cosmic particle accelerators and arguments leading to the likely importance of diffusive shock acceleration as a general explanation. The basic theory of diffusive shock acceleration is outlined, followed by a discussion of some of the key issues that still prevent us from a full understanding of its outcomes. Some recent insights are mentioned at the end that may help direct ultimate resolution of our uncertainties.

  2. Terahertz radiation from laser accelerated electron bunches

    E-Print Network [OSTI]

    2004-01-01T23:59:59.000Z

    NUMBER 5 MAY 2004 Terahertz radiation from laser acceleratedand millimeter wave radiation from laser acceleratedNo. 5, May 2004 Terahertz radiation from laser accelerated

  3. ASTA at Fermilab: Accelerator Physics and Accelerator Education Programs at the Modern Accelerator R&D Users Facility for HEP and Accelerator Applications.

    SciTech Connect (OSTI)

    Shiltsev, V.; Piot, P.

    2013-09-01T23:59:59.000Z

    We present the current and planned beam physics research program and accelerator education program at Advanced Superconducting Test Accelerator (ASTA) at Fermilab.

  4. Accelerating CHP Deployment, United States Energy Association...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Accelerating CHP Deployment, United States Energy Association (USEA), August 2011 Accelerating CHP Deployment, United States Energy Association (USEA), August 2011 The United...

  5. Berkeley Lab Compact Accelerator Sets World Record

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Berkeley Lab Particle Accelerator Sets World Record Berkeley Lab Particle Accelerator Sets World Record Simulations at NERSC Help Validate Experimental Laser-Plasma Design December...

  6. Accelerating DSMC data extraction.

    SciTech Connect (OSTI)

    Gallis, Michail A.; Piekos, Edward Stanley

    2006-10-01T23:59:59.000Z

    In many direct simulation Monte Carlo (DSMC) simulations, the majority of computation time is consumed after the flowfield reaches a steady state. This situation occurs when the desired output quantities are small compared to the background fluctuations. For example, gas flows in many microelectromechanical systems (MEMS) have mean speeds more than two orders of magnitude smaller than the thermal speeds of the molecules themselves. The current solution to this problem is to collect sufficient samples to achieve the desired resolution. This can be an arduous process because the error is inversely proportional to the square root of the number of samples so we must, for example, quadruple the samples to cut the error in half. This work is intended to improve this situation by employing more advanced techniques, from fields other than solely statistics, for determining the output quantities. Our strategy centers on exploiting information neglected by current techniques, which collect moments in each cell without regard to one another, values in neighboring cells, nor their evolution in time. Unlike many previous acceleration techniques that modify the method itself, the techniques examined in this work strictly post-process so they may be applied to any DSMC code without affecting its fidelity or generality. Many potential methods are drawn from successful applications in a diverse range of areas, from ultrasound imaging to financial market analysis. The most promising methods exploit relationships between variables in space, which always exist in DSMC due to the absence of shocks. Disparate techniques were shown to produce similar error reductions, suggesting that the results shown in this report may be typical of what is possible using these methods. Sample count reduction factors of approximately three to five were found to be typical, although factors exceeding ten were shown on some variables under some techniques.

  7. Generation and Characterization of Electron Bunches with Ramped Current Profiles in a Dual-Frequency Superconducting Linear Accelerator

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Piot, P [Northern Illinois U.; Fermilab; Behrens, C; Gerth, C; Dohlus, M [DESY; Lemery, F; Mihalcea, D [Northern Illinois U.; Stoltz, P [Tech-X, Boulder; Vogt, M [DESY

    2011-09-07T23:59:59.000Z

    We report on the successful experimental generation of electron bunches with ramped current profiles. The technique relies on impressing nonlinear correlations in the longitudinal phase space using a superconducing radiofrequency linear accelerator operating at two frequencies and a current-enhancing dispersive section. The produced {approx} 700-MeV bunches have peak currents of the order of a kilo-Ampere. Data taken for various accelerator settings demonstrate the versatility of the method and in particular its ability to produce current profiles that have a quasi-linear dependency on the longitudinal (temporal) coordinate. The measured bunch parameters are shown, via numerical simulations, to produce gigavolt-per-meter peak accelerating electric fields with transformer ratios larger than 2 in dielectric-lined waveguides.

  8. Linear Accelerator | Advanced Photon Source

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    photo below). Selective phasing of the electric field accelerates the electrons to 450 million volts (MeV). At 450 MeV, the electrons are relativistic: they are traveling at...

  9. The Sustainable Building-Accelerator 

    E-Print Network [OSTI]

    Maassen, W.H.

    2011-01-01T23:59:59.000Z

    stages to generate optimal design solutions. The ''Sustainable Building - Accelerator'' supports stakeholders to decide on sustainable solutions by giving them cost and benefit information of design solutions. This information provides them...

  10. Israel Careers ACCELERATE YOUR FUTURE

    E-Print Network [OSTI]

    Rimon, Elon

    Lithography Control products within the product lifecycle process including defining requirements, settingIsrael Careers ACCELERATE YOUR FUTURE Product Marketing Manager Job Description: Product Marketing Manager at the Optical Metrology Division is responsible for product strategy and customer interface

  11. Sequentially pulsed traveling wave accelerator

    DOE Patents [OSTI]

    Caporaso, George J. (Livermore, CA); Nelson, Scott D. (Patterson, CA); Poole, Brian R. (Tracy, CA)

    2009-08-18T23:59:59.000Z

    A sequentially pulsed traveling wave compact accelerator having two or more pulse forming lines each with a switch for producing a short acceleration pulse along a short length of a beam tube, and a trigger mechanism for sequentially triggering the switches so that a traveling axial electric field is produced along the beam tube in synchronism with an axially traversing pulsed beam of charged particles to serially impart energy to the particle beam.

  12. BRIEF HISTORY OF FFAG ACCELERATORS.

    SciTech Connect (OSTI)

    RUGGIERO, A.

    2006-12-04T23:59:59.000Z

    Colleagues of mine have asked me few times why we have today so much interest in Fixed-Field Alternating-Gradient (FFAG) accelerators when these were invented a long time ago, and have always been ignored since then. I try here to give a reply with a short history of FFAG accelerators, at least as I know it. I take also the opportunity to clarify few definitions.

  13. Broadband dielectric response of glycerol and propylene carbonate: a comparison

    E-Print Network [OSTI]

    P. Lunkenheimer; U. Schneider; R. Brand; A. Loidl

    1998-12-15T23:59:59.000Z

    Dielectric data on glycerol and propylene carbonate covering 18 decades of frequency are presented and compared to each other. Both materials exhibit qualitatively similar behavior except for marked differences in the high-frequency region just below the boson peak. The results on both materials are consistent with the mode coupling theory of the glass transition.

  14. Effect of mechanical parameters on dielectric elastomer minimum energy structures

    E-Print Network [OSTI]

    Floreano, Dario

    Effect of mechanical parameters on dielectric elastomer minimum energy structures Jun Shintake energy structures Jun Shintake*a,b , Samuel Rosseta , Dario Floreanob , Herbert R. Sheaa a Microsystems for Space Technologies Laboratory, Ecole Polytechnique Fédérale de Lausanne (EPFL), Neuchâtel, Switzerland b

  15. Dielectric nanostructures for broadband light trapping in organic solar cells

    E-Print Network [OSTI]

    Fan, Shanhui

    Dielectric nanostructures for broadband light trapping in organic solar cells Aaswath Raman, Zongfu@stanford.edu Abstract: Organic bulk heterojunction solar cells are a promising candidate for low-cost next lying on top of the organic solar cell stack produce a 8-15% increase in photocurrent for a model

  16. Temperature and moisture dependence of dielectric constant for silica aerogels

    SciTech Connect (OSTI)

    Hrubesh, L.H., LLNL

    1997-03-01T23:59:59.000Z

    The dielectric constants of silica aerogels are among the lowest measured for any solid material. The silica aerogels also exhibit low thermal expansion and are thermally stable to temperatures exceeding 500{degrees}C. However, due to the open porosity and large surface areas for aerogels, their dielectric constants are strongly affected by moisture and temperature. This paper presents data for the dielectric constants of silica aerogels as a function of moisture content at 25{degrees}C, and as a function of temperature, for temperatures in the range from 25{degrees}C to 450{degrees}C. Dielectric constant data are also given for silica aerogels that are heat treated in dry nitrogen at 500{degrees}C, then cooled to 25{degrees}C for measurements in dry air. All measurements are made on bulk aerogel spheres at 22GHz microwave frequency, using a cavity perturbation method. The results of the dependence found here for bulk materials can be inferred to apply also to thin films of silica aerogels having similar nano-structures and densities.

  17. 8 IEEE TRANSACTIONS ON PLASMA SCIENCE, VOL. 33, NO. 1, FEBRUARY 2005 Radiation From Laser Accelerated Electron Bunches

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    . The short-pulse nature of the acceler- ated bunches and high particle energy offer the possibility of gen mod- ulation (wakefield) that can trap background electrons and accel- erate them to high energies

  18. Substrate dielectric effects on graphene field effect transistors

    SciTech Connect (OSTI)

    Hu, Zhaoying; Prasad Sinha, Dhiraj; Ung Lee, Ji, E-mail: jlee1@albany.edu; Liehr, Michael [College of Nanoscale Science and Engineering, The State University of New York at Albany, Albany, New York 12203 (United States)

    2014-05-21T23:59:59.000Z

    Graphene is emerging as a promising material for future electronics and optoelectronics applications due to its unique electronic structure. Understanding the graphene-dielectric interaction is of vital importance for the development of graphene field effect transistors (FETs) and other novel graphene devices. Here, we extend the exploration of substrate dielectrics from conventionally used thermally grown SiO{sub 2} and hexagonal boron nitride films to technologically relevant deposited dielectrics used in semiconductor industry. A systematic analysis of morphology and optical and electrical properties was performed to study the effects of different substrates (SiO{sub 2}, HfO{sub 2}, Al{sub 2}O{sub 3}, tetraethyl orthosilicate (TEOS)-oxide, and Si{sub 3}N{sub 4}) on the carrier transport of chemical vapor deposition-derived graphene FET devices. As baseline, we use graphene FETs fabricated on thermal SiO{sub 2} with a relatively high carrier mobility of 10?000 cm{sup 2}/(V s). Among the deposited dielectrics studied, silicon nitride showed the highest mobility, comparable to the properties of graphene fabricated on thermal SiO{sub 2}. We conclude that this result comes from lower long range scattering and short range scattering rates in the nitride compared those in the other deposited films. The carrier fluctuation caused by substrates, however, seems to be the main contributing factor for mobility degradation, as a universal mobility-disorder density product is observed for all the dielectrics examined. The extrinsic doping trend is further confirmed by Raman spectra. We also provide, for the first time, correlation between the intensity ratio of G peak and 2D peak in the Raman spectra to the carrier mobility of graphene for different substrates.

  19. Multiple nonlinear dielectric resonance of ultra-long silver trimolybdate nanowires

    SciTech Connect (OSTI)

    Wang, Guang-Sheng, E-mail: wanggsh@buaa.edu.cn [Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191, PR China. (China); Wen, Bo [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China); He, Shuai; Guo, Lin [Key Laboratory of Bio-Inspired Smart Interfacial Science and Technology of Ministry of Education, School of Chemistry and Environment, Beihang University, Beijing 100191 (China); Cao, Mao-Sheng, E-mail: caomaosheng@bit.edu.cn [School of Materials Science and Engineering, Beijing Institute of Technology, Beijing 100081 (China)

    2013-06-01T23:59:59.000Z

    The silver molybdate nanowires (NWs) have been synthesized and characterized. The multiple dielectric resonant peaks of the nanocomposites filled with silver molybdate nanowires have been studied from 2 to 18 GHz. The as-established equivalent circuit model of the silver molybdate nanowires were employed to explain the nonlinear dielectric resonant behavior. - Graphical abstract: The ultra-long silver trimolybdate nanowires were synthesized and the dielectric peoperties of the products were studied from 2 to 18 GHz. The as-established equivalent circuit model of the silver molybdate nanowires were employed to explain the nonlinear dielectric resonant behavior. Highlights: • The silver molybdate nanowires have been synthesized and characterized. • The dielectric properties of the silver molybdate/ paraffin nanocomposites have been studied. • Higher concentration of silver trimolybdate enhances the dielectric properties of composite. • The dielectric behaviors were explained based on the as-established equivalent circuit mode.

  20. Theory of factors limiting high gradient operation of warm accelerating structures

    SciTech Connect (OSTI)

    Nusinovich, Gregory S. [University of Maryland; Antonsen, Thomas M. [University of Maryland; Kishek, Rami [University of Maryland

    2014-07-25T23:59:59.000Z

    This final report summarizes the research performed during the time period from 8/1/2010 to 7/31/2013. It consists of two parts describing our studies in two directions: (a) analysis of factors limiting operation of dielectric-loaded accelerating (DLA) structures where the main problem is the occurrence of multipactor on dielectric surfaces, and (b) studies of effects associated with either RF magnetic or RF electric fields which may cause the RF breakdown in high-gradient metallic accelerating structures. In the studies of DLA structures, at least, two accomplishments should be mentioned: the development of a 3D non-stationary, self-consistent code describing the multipactor phenomena and yielding very good agreement with some experimental data obtained in joint ANL/NRL experiments. In the metallic structures, such phenomena as the heating and melting of micro-particles (metallic dust) by RF electric and magnetic fields in single-shot and rep-rate regimes is analyzed. Also, such processes in micro-protrusions on the structure surfaces as heating and melting due to the field emitted current and the Nottingham effect are thoroughly investigated with the account for space charge of emitted current on the field emission from the tip.

  1. High Gradient Two-Beam Electron Accelerator

    SciTech Connect (OSTI)

    Jiang, Y. [Beam Physics Laboratory, Yale University, 272 Whitney Ave., New Haven, CT 06511 (United States); Kazakov, S. Yu. [Omega-P, Inc., 258 Bradley St., New Haven, CT 06510 (United States); Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Kuzikov, S. V. [Omega-P, Inc., 258 Bradley St., New Haven, CT 06510 (United States); Institute of Applied Physics, Nizhny Novgorod, 603600 (Russian Federation); Hirshfield, J. L. [Beam Physics Laboratory, Yale University, 272 Whitney Ave., New Haven, CT 06511 (United States); Omega-P, Inc., 258 Bradley St., New Haven, CT 06510 (United States)

    2010-11-04T23:59:59.000Z

    A high-gradient two-beam electron accelerator structure using detuned cavities is described. A self-consistent theory based on a circuit model is presented to calculate idealized acceleration gradient, transformer ratio, and efficiency for energy transfer from the drive beam to the accelerated beam. Experimental efforts are being carried out to demonstrate this acceleration concept.

  2. RADIO EMISSION OF SOLAR FLARE PARTICLE ACCELERATION

    E-Print Network [OSTI]

    RADIO EMISSION OF SOLAR FLARE PARTICLE ACCELERATION A. O. Benz Abstract The solar corona is a very be considered as a particle accelerator. The free mobility of charged particles in a dilute plasma to accelerate particles in resonance. From a plasma physics point of view, acceleration is not surprising

  3. Accelerator and electrodynamics capability review

    SciTech Connect (OSTI)

    Jones, Kevin W [Los Alamos National Laboratory

    2010-01-01T23:59:59.000Z

    Los Alamos National Laboratory (LANL) uses capability reviews to assess the science, technology and engineering (STE) quality and institutional integration and to advise Laboratory Management on the current and future health of the STE. Capability reviews address the STE integration that LANL uses to meet mission requirements. The Capability Review Committees serve a dual role of providing assessment of the Laboratory's technical contributions and integration towards its missions and providing advice to Laboratory Management. The assessments and advice are documented in reports prepared by the Capability Review Committees that are delivered to the Director and to the Principal Associate Director for Science, Technology and Engineering (PADSTE). Laboratory Management will use this report for STE assessment and planning. LANL has defined fifteen STE capabilities. Electrodynamics and Accelerators is one of the seven STE capabilities that LANL Management (Director, PADSTE, technical Associate Directors) has identified for review in Fiscal Year (FY) 2010. Accelerators and electrodynamics at LANL comprise a blend of large-scale facilities and innovative small-scale research with a growing focus on national security applications. This review is organized into five topical areas: (1) Free Electron Lasers; (2) Linear Accelerator Science and Technology; (3) Advanced Electromagnetics; (4) Next Generation Accelerator Concepts; and (5) National Security Accelerator Applications. The focus is on innovative technology with an emphasis on applications relevant to Laboratory mission. The role of Laboratory Directed Research and Development (LDRD) in support of accelerators/electrodynamics will be discussed. The review provides an opportunity for interaction with early career staff. Program sponsors and customers will provide their input on the value of the accelerator and electrodynamics capability to the Laboratory mission.

  4. Ultra-high vacuum photoelectron linear accelerator

    DOE Patents [OSTI]

    Yu, David U.L.; Luo, Yan

    2013-07-16T23:59:59.000Z

    An rf linear accelerator for producing an electron beam. The outer wall of the rf cavity of said linear accelerator being perforated to allow gas inside said rf cavity to flow to a pressure chamber surrounding said rf cavity and having means of ultra high vacuum pumping of the cathode of said rf linear accelerator. Said rf linear accelerator is used to accelerate polarized or unpolarized electrons produced by a photocathode, or to accelerate thermally heated electrons produced by a thermionic cathode, or to accelerate rf heated field emission electrons produced by a field emission cathode.

  5. Pre-breakdown cavitation development in the dielectric fluid in the inhomogeneous, pulsed electric fields

    E-Print Network [OSTI]

    Mikhail N. Shneider; Mikhail Pekker

    2014-12-01T23:59:59.000Z

    We consider the development of pre-breakdown cavitation nanopores appearing in the dielectric fluid under the influence of the electrostrictive stresses in the inhomogeneous pulsed electric field. It is shown that three characteristic regions can be distinguished near the needle electrode. In the first region, where the electric field gradient is greatest, the cavitation nanopores, occurring during the voltage nanosecond pulse, may grow to the size at which an electron accelerated by the field inside the pores can acquire enough energy for excitation and ionization of the liquid on the opposite pore wall, i.e., the breakdown conditions are satisfied. In the second region, the negative pressure caused by the electrostriction is large enough for the cavitation initiation (which can be registered by optical methods), but, during the voltage pulse, the pores do not reach the size at which the potential difference across their borders becomes sufficient for ionization or excitation of water molecules. And, in the third, the development of cavitation is impossible, due to an insufficient level of the negative pressure: in this area, the spontaneously occurring micropores do not grow and collapse under the influence of surface tension forces. This paper discusses the expansion dynamics of the cavitation pores and their most probable shape.

  6. Accelerator Physics Accelerators form the backbone of SLAC's on-site experimental program. Research at SLAC

    E-Print Network [OSTI]

    Wechsler, Risa H.

    #12;Accelerator Physics Accelerators form the backbone of SLAC's on-site experimental program. Research at SLAC is continually improving accelerators, both here and at other laboratories, and paving the way for a new generation of particle acceleration technology. SLAC's famous linear accelerator

  7. X-ray driven channeling acceleration in crystals and carbon nanotubes

    SciTech Connect (OSTI)

    Shin, Young-Min [Department of Physics, Northern Illinois Center for Accelerator and Detector Development (NICADD), Northern Illinois University, Dekalb, Illinois 60115 (United States) [Department of Physics, Northern Illinois Center for Accelerator and Detector Development (NICADD), Northern Illinois University, Dekalb, Illinois 60115 (United States); Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States); Still, Dean A.; Shiltsev, Vladimir [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)] [Fermi National Accelerator Laboratory, Batavia, Illinois 60510 (United States)

    2013-12-15T23:59:59.000Z

    Acceleration of particles channeling in a crystal by means of diffracted x-rays via Bormann anomalous transmission was conceived for heavy ions and muons by Tajima and Cavenago [Phys. Rev. Lett. 59, 1440 (1987)], which potentially offers an appreciably high field gradient on the order of GV/cm. The theoretical model of the high gradient acceleration has been studied in two kinds of atomic structure, crystals and carbon nanotubes (CNTs), with analytic calculations and electromagnetic eigenmode simulations. A range of acceleration gradients and cutoffs of the x-ray power (the lowest power limit to overcome the Bremsstrahlung radiation losses) are characterized in terms of the lattice constants, unit cell sizes, and photon energies. The parametric analysis indicates that the required x-ray power can be reduced to an order of megawatt by replacing crystals with CNTs. Eventually, the equivalent dielectric approximation of a multi-wall nanotube shows that 250–810 MeV muons can be synchronously coupled with x-rays of 0.65–1.32 keV in the accelerating structure.

  8. Superconducting Magnets for Particle Accelerators

    E-Print Network [OSTI]

    Rossi, L

    2012-01-01T23:59:59.000Z

    Superconductivity has been the most influential technology in the field of accelerators in the last 30 years. Since the commissioning of the Tevatron, which demonstrated the use and operability of superconductivity on a large scale, superconducting magnets and rf cavities have been at the heart of all new large accelerators. Superconducting magnets have been the invariable choice for large colliders, as well as cyclotrons and large synchrotrons. In spite of the long history of success, superconductivity remains a difficult technology, requires adequate R&D and suitable preparation, and has a relatively high cost. Hence, it is not surprising that the development has also been marked by a few setbacks. This article is a review of the main superconducting accelerator magnet projects; it highlights the main characteristics and main achievements, and gives a perspective on the development of superconducting magnets for the future generation of very high energy colliders.

  9. Symposium on accelerator mass spectrometry

    SciTech Connect (OSTI)

    None

    1981-01-01T23:59:59.000Z

    The area of accelerator mass spectrometry has expanded considerably over the past few years and established itself as an independent and interdisciplinary research field. Three years have passed since the first meeting was held at Rochester. A Symposium on Accelerator Mass Spectrometry was held at Argonne on May 11-13, 1981. In attendance were 96 scientists of whom 26 were from outside the United States. The present proceedings document the program and excitement of the field. Papers are arranged according to the original program. A few papers not presented at the meeting have been added to complete the information on the status of accelerator mass spectrometry. Individual papers were prepared separately for the data base.

  10. Efficient control of accelerator maps

    E-Print Network [OSTI]

    Jehan Boreux; Timoteo Carletti; Charalampos Skokos; Yannis Papaphilippou; Michel Vittot

    2011-09-21T23:59:59.000Z

    Recently, the Hamiltonian Control Theory was used in [Boreux et al.] to increase the dynamic aperture of a ring particle accelerator having a localized thin sextupole magnet. In this letter, these results are extended by proving that a simplified version of the obtained general control term leads to significant improvements of the dynamic aperture of the uncontrolled model. In addition, the dynamics of flat beams based on the same accelerator model can be significantly improved by a reduced controlled term applied in only 1 degree of freedom.

  11. Accelerated dynamics simulations of nanotubes.

    SciTech Connect (OSTI)

    Uberuaga, B. P. (Blas Pedro); Stuart, S. J. (Steve J.); Voter, A. F.

    2002-01-01T23:59:59.000Z

    We report on the application of accelerated dynamics techniques to the study of carbon nanotubes. We have used the parallel replica method and temperature accelerated dynamics simulations are currently in progress. In the parallel replica study, we have stretched tubes at a rate significantly lower than that used in previous studies. In these preliminary results, we find that there are qualitative differences in the rupture of the nanotubes at different temperatures. We plan on extending this investigation to include nanotubes of various chiralities. We also plan on exploring unique geometries of nanotubes.

  12. Weak-Chaos Ratchet Accelerator

    E-Print Network [OSTI]

    Itzhack Dana; Vladislav B. Roitberg

    2012-05-28T23:59:59.000Z

    Classical Hamiltonian systems with a mixed phase space and some asymmetry may exhibit chaotic ratchet effects. The most significant such effect is a directed momentum current or acceleration. In known model systems, this effect may arise only for sufficiently strong chaos. In this paper, a Hamiltonian ratchet accelerator is introduced, featuring a momentum current for arbitrarily weak chaos. The system is a realistic, generalized kicked rotor and is exactly solvable to some extent, leading to analytical expressions for the momentum current. While this current arises also for relatively strong chaos, the maximal current is shown to occur, at least in one case, precisely in a limit of arbitrarily weak chaos.

  13. Centralized digital control of accelerators

    SciTech Connect (OSTI)

    Melen, R.E.

    1983-09-01T23:59:59.000Z

    In contrasting the title of this paper with a second paper to be presented at this conference entitled Distributed Digital Control of Accelerators, a potential reader might be led to believe that this paper will focus on systems whose computing intelligence is centered in one or more computers in a centralized location. Instead, this paper will describe the architectural evolution of SLAC's computer based accelerator control systems with respect to the distribution of their intelligence. However, the use of the word centralized in the title is appropriate because these systems are based on the use of centralized large and computationally powerful processors that are typically supported by networks of smaller distributed processors.

  14. Electron Cloud Effects in Accelerators

    SciTech Connect (OSTI)

    Furman, M.A.

    2012-11-30T23:59:59.000Z

    Abstract We present a brief summary of various aspects of the electron-cloud effect (ECE) in accelerators. For further details, the reader is encouraged to refer to the proceedings of many prior workshops, either dedicated to EC or with significant EC contents, including the entire ?ECLOUD? series [1?22]. In addition, the proceedings of the various flavors of Particle Accelerator Conferences [23] contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series [24] contains one dedicated issue, and several occasional articles, on EC. An extensive reference database is the LHC website on EC [25].

  15. COMPASS, the COMmunity Petascale project for Accelerator Science and Simulation, a broad computational accelerator physics

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    COMPASS, the COMmunity Petascale project for Accelerator Science and Simulation, a broad at Lawrence Livermore National Laboratory. #12;COMPASS, the COMmunity Petascale project for Accelerator for materials studies. COMPASS, the Community Petascale Project for Accelerator Science and Simulation

  16. Dielectric waveguide gas-filled stark shift modulator

    DOE Patents [OSTI]

    Hutchinson, Donald P.; Richards, Roger K.

    2003-07-22T23:59:59.000Z

    An optical modulator includes a dielectric waveguide for receiving an optical beam and coupling energy of the optical beam into the waveguide. At least one Stark material is provided in the waveguide. A bias circuit generates a bias signal to produce an electrical field across the Stark material to shift at least one of the Stark absorption frequencies towards the frequency of the optical beam. A circuit for producing a time varying electric field across the Stark material modulates the optical beam. At least a portion of the bias field can be generated by an alternating bias signal, such as a square wave. A method of modulating optical signals includes the steps of providing a dielectric waveguide for receiving an optical beam and coupling energy of the optical beam into the waveguide, the waveguide having at least one Stark material disposed therein, and varying an electric field imposed across the Stark material.

  17. The momentum of an electromagnetic wave inside a dielectric

    SciTech Connect (OSTI)

    Testa, Massimo, E-mail: massimo.testa@roma1.infn.it

    2013-09-15T23:59:59.000Z

    The problem of assigning a momentum to an electromagnetic wave packet propagating inside an insulator has become known under the name of the Abraham–Minkowski controversy. In the present paper we re-examine this issue making the hypothesis that the forces exerted on an insulator by an electromagnetic field do not distinguish between polarization and free charges. Under this assumption we show that the Abraham expression for the radiation mechanical momentum is highly favored. -- Highlights: •We discuss an approximation to treat electrodynamics of a dielectric material. •We support the Abraham form for the electromagnetic momentum. •We deduce Snell’s law from the conservation of the Abraham momentum. •We show how to deal with the electric field discontinuity at the dielectric boundary.

  18. Double dielectric passivation layer on InAs

    E-Print Network [OSTI]

    Egley, James Lee

    1985-01-01T23:59:59.000Z

    ) August 1985 ABSTRACT Double Dielectric Passivation Layer on InAs. (August 1985) James Lee Egley, B. S. , Lewis University Chairman of Advisory Committee: Yellapu Anjaneyulu This thesis investigates the characteristics of the substrate surface... as the lubricant. The wafers were polished to a mirror-like finish. An alumina slurry was also tried for this step, but it was found that the chemicals contained in the slurry etched the surface. After the above mechanical polishing the samples were removed...

  19. Ferroelectric and dielectric properties of ferrite-ferroelectric ceramic composites

    SciTech Connect (OSTI)

    Elena Ciomaga, Cristina; Maria Neagu, Alexandra; Valentin Pop, Mihai; Mitoseriu, Liliana [Faculty of Physics, 'Al. I. Cuza' University of Iasi 700506, Iasi (Romania); Airimioaei, Mirela [Faculty of Chemistry, 'Al. I. Cuza' University of Iasi 700506, Iasi, Romania and Dept. Chemistry and Process Engineering, University of Genoa, P-le Kennedy no. 1, I-16129, Genoa (Italy); Tascu, Sorin [RAMTECH Faculty of Physics, 'Al. I. Cuza' University of Iasi 700506 (Romania); Schileo, Giorgio [Christian Doppler Laboratory for Advanced Ferroic Oxides, Sheffield Hallam University, Howard Street, Sheffield S1 1WB (United Kingdom); Galassi, Carmen [CNR-ISTEC, Via Granarolo no. 64, I-48018 Faenza (Italy)

    2013-02-21T23:59:59.000Z

    Particulate composites of ferrite and ferroelectric phases with xNiFe{sub 2}O{sub 4} (NF) and (1 - x)Pb{sub 0.988}(Zr{sub 0.52}Ti{sub 0.48}){sub 0.976}Nb{sub 0.024}O{sub 3} (where x = 2, 10, 20, 30, 50, 70, and 100 wt. %) were prepared in situ by sol-gel method. The presence of a diphase composition was confirmed by X-ray diffraction while the microstructure of the composites was studied by scanning electron microscopy revealing a good mixing of the two phases and a good densification of the bulk ceramics. The dielectric permittivity shows usual dielectric dispersion behavior with increasing frequency due to Maxwell-Wagner interfacial polarization. AC conductivity measurements made in frequency range 1 Hz-1 MHz suggest that the conduction process is due to mixed polaron hopping. The effect of NF phase concentration on the P-E and M-H hysteresis behavior and dielectric properties of the composites was investigated. At low NF concentration a sharp ferro-paraelectric transition peak can be observed at around 360 Degree-Sign C while for higher NF concentrations a trend to a diffuse phase transition occurs. All the composite samples exhibit typical ferromagnetic hysteresis loops, indicating the presence of ordered magnetic structure.

  20. Microwave Dielectric Heating of Drops in Microfluidic Devices

    E-Print Network [OSTI]

    David Issadore; Katherine J. Humphry; Keith A. Brown; Lori Sandberg; David Weitz; Robert M. Westervelt

    2009-01-09T23:59:59.000Z

    We present a technique to locally and rapidly heat water drops in microfluidic devices with microwave dielectric heating. Water absorbs microwave power more efficiently than polymers, glass, and oils due to its permanent molecular dipole moment that has a large dielectric loss at GHz frequencies. The relevant heat capacity of the system is a single thermally isolated picoliter drop of water and this enables very fast thermal cycling. We demonstrate microwave dielectric heating in a microfluidic device that integrates a flow-focusing drop maker, drop splitters, and metal electrodes to locally deliver microwave power from an inexpensive, commercially available 3.0 GHz source and amplifier. The temperature of the drops is measured by observing the temperature dependent fluorescence intensity of cadmium selenide nanocrystals suspended in the water drops. We demonstrate characteristic heating times as short as 15 ms to steady-state temperatures as large as 30 degrees C above the base temperature of the microfluidic device. Many common biological and chemical applications require rapid and local control of temperature, such as PCR amplification of DNA, and can benefit from this new technique.

  1. The Hawking effect in dielectric media and the Hopfield model

    E-Print Network [OSTI]

    F. Belgiorno; S. L. Cacciatori; F. Dalla Piazza

    2014-11-28T23:59:59.000Z

    We consider the so-called Hopfield model for the electromagnetic field in a dielectric dispersive medium in a framework in which one allows a space-time dependence of microscopic parameters, aimed to a phenomenological description of a space-time varying dielectric perturbation induced by means of the Kerr effect. We discuss the analogue Hawking effect, by first analyzing the geometrical optics for the Hopfield model, and then by introducing a simplified model which has the bonus to avoid many difficulties which are involved in the full Hopfield model, still keeping the same dispersion relation. Amplitude calculations are indicated, and generalized Manley-Rowe identities are derived in a quantum scattering theory framework. Our main result is an analytical calculation of the spontaneous thermal emission in the single-branch case, which is provided non perturbatively for the first time in the framework of dielectric black holes. An universal mechanism for thermality between optical black holes and acoustic black holes is also pointed out.

  2. Phase Stable Net Acceleration of Electrons From a Two-Stage Optical Accelerator

    SciTech Connect (OSTI)

    Sears, Christopher M.S.; /SLAC /Munich, Max Planck Inst. Quantenopt.; Colby, Eric; England, R.J.; Ischebeck, Rasmus; McGuinness, Christopher; Nelson, Janice; Noble, Robert; Siemann, Robert H.; Spencer, James; Walz, Dieter; /SLAC; Plettner, Tomas; Byer, Robert L.; /Stanford U., Phys. Dept.

    2011-11-11T23:59:59.000Z

    In this article we demonstrate the net acceleration of relativistic electrons using a direct, in-vacuum interaction with a laser. In the experiment, an electron beam from a conventional accelerator is first energy modulated at optical frequencies in an inverse-free-electron-laser and bunched in a chicane. This is followed by a second stage optical accelerator to obtain net acceleration. The optical phase between accelerator stages is monitored and controlled in order to scan the accelerating phase and observe net acceleration and deceleration. Phase jitter measurements indicate control of the phase to {approx}13{sup o} allowing for stable net acceleration of electrons with lasers.

  3. Fresnel diffraction patterns as accelerating beams

    E-Print Network [OSTI]

    Zhang, Yiqi; Zheng, Huaibin; Wu, Zhenkun; Li, Yuanyuan; Lu, Keqing; Zhang, Yanpeng

    2013-01-01T23:59:59.000Z

    We demonstrate that beams originating from Fresnel diffraction patterns are self-accelerating in free space. In addition to accelerating and self-healing, they also exhibit parabolic deceleration property, which is in stark contrast to other accelerating beams. We find that the trajectory of Fresnel paraxial accelerating beams is similar to that of nonparaxial Weber beams. Decelerating and accelerating regions are separated by a critical propagation distance, at which no acceleration is present. During deceleration, the Fresnel diffraction beams undergo self-smoothing, in which oscillations of the diffracted waves gradually focus and smooth out at the critical distance.

  4. Physics Needs for Future Accelerators

    E-Print Network [OSTI]

    Lykken, J D

    2000-01-01T23:59:59.000Z

    Contents: 1. Prologomena to any meta future physics 1.1 Physics needs for building future accelerators 1.2 Physics needs for funding future accelerators 2. Physics questions for future accelerators 2.1 Crimes and misapprehensions 2.1.1 Organized religion 2.1.2 Feudalism 2.1.3 Trotsky was right 2.2 The Standard Model as an effective field theory 2.3 What is the scale of new physics? 2.4 What could be out there? 2.5 Model-independent conclusions 3. Future accelerators 3.1 What is the physics driving the LHC? 3.2 What is the physics driving the LC? 3.2.1 Higgs physics is golden 3.2.2 LHC won't be sufficient to unravel the new physics as the TeV scale 3.2.3 LC precision measurements can pin down new physics scales 3.3 Why a Neutrino Factory? 3.4 Pushing the energy frontier

  5. Petawatt pulsed-power accelerator

    DOE Patents [OSTI]

    Stygar, William A. (Albuquerque, NM); Cuneo, Michael E. (Albuquerque, NM); Headley, Daniel I. (Albuquerque, NM); Ives, Harry C. (Albuquerque, NM); Ives, legal representative; Berry Cottrell (Albuquerque, NM); Leeper, Ramon J. (Albuquerque, NM); Mazarakis, Michael G. (Albuquerque, NM); Olson, Craig L. (Albuquerque, NM); Porter, John L. (Sandia Park, NM); Wagoner; Tim C. (Albuquerque, NM)

    2010-03-16T23:59:59.000Z

    A petawatt pulsed-power accelerator can be driven by various types of electrical-pulse generators, including conventional Marx generators and linear-transformer drivers. The pulsed-power accelerator can be configured to drive an electrical load from one- or two-sides. Various types of loads can be driven; for example, the accelerator can be used to drive a high-current z-pinch load. When driven by slow-pulse generators (e.g., conventional Marx generators), the accelerator comprises an oil section comprising at least one pulse-generator level having a plurality of pulse generators; a water section comprising a pulse-forming circuit for each pulse generator and a level of monolithic triplate radial-transmission-line impedance transformers, that have variable impedance profiles, for each pulse-generator level; and a vacuum section comprising triplate magnetically insulated transmission lines that feed an electrical load. When driven by LTD generators or other fast-pulse generators, the need for the pulse-forming circuits in the water section can be eliminated.

  6. THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY

    E-Print Network [OSTI]

    175 THE RADIOLOGICAL RESEARCH ACCELERATOR FACILITY #12;176 #12;177 THE RADIOLOGICAL RESEARCH the microbeam and the track-segment facilities have been utilized in various investigations. Table 1 lists-segment facility. Samples are treated with graded doses of radical scavengers to observe changes in the cluster

  7. Accelerating Multimedia with Enhanced Microprocessors

    E-Print Network [OSTI]

    Lee, Ruby B.

    Accelerating Multimedia with Enhanced Microprocessors A minimalistic set of multimedia instructions introduced into PA-RISC microprocessors implements SIMD-MIMD parallelism with insignificant changes to the underlying microprocessor. Thus, a software video decoder attains MPEG video and audio decom- pression

  8. Accelerators for Intensity Frontier Research

    SciTech Connect (OSTI)

    Derwent, Paul; /Fermilab

    2012-05-11T23:59:59.000Z

    In 2008, the Particle Physics Project Prioritization Panel identified three frontiers for research in high energy physics, the Energy Frontier, the Intensity Frontier, and the Cosmic Frontier. In this paper, I will describe how Fermilab is configuring and upgrading the accelerator complex, prior to the development of Project X, in support of the Intensity Frontier.

  9. Physics Needs for Future Accelerators

    E-Print Network [OSTI]

    Joseph D. Lykken

    2000-01-30T23:59:59.000Z

    Contents: 1. Prologomena to any meta future physics 1.1 Physics needs for building future accelerators 1.2 Physics needs for funding future accelerators 2. Physics questions for future accelerators 2.1 Crimes and misapprehensions 2.1.1 Organized religion 2.1.2 Feudalism 2.1.3 Trotsky was right 2.2 The Standard Model as an effective field theory 2.3 What is the scale of new physics? 2.4 What could be out there? 2.5 Model-independent conclusions 3. Future accelerators 3.1 What is the physics driving the LHC? 3.2 What is the physics driving the LC? 3.2.1 Higgs physics is golden 3.2.2 LHC won't be sufficient to unravel the new physics as the TeV scale 3.2.3 LC precision measurements can pin down new physics scales 3.3 Why a Neutrino Factory? 3.4 Pushing the energy frontier

  10. Thomas Jefferson National Accelerator Facility

    SciTech Connect (OSTI)

    Joseph Grames, Douglas Higinbotham, Hugh Montgomery

    2010-09-01T23:59:59.000Z

    The Thomas Jefferson National Accelerator Facility (Jefferson Lab) in Newport News, Virginia, USA, is one of ten national laboratories under the aegis of the Office of Science of the U.S. Department of Energy (DOE). It is managed and operated by Jefferson Science Associates, LLC. The primary facility at Jefferson Lab is the Continuous Electron Beam Accelerator Facility (CEBAF) as shown in an aerial photograph in Figure 1. Jefferson Lab was created in 1984 as CEBAF and started operations for physics in 1995. The accelerator uses superconducting radio-frequency (srf) techniques to generate high-quality beams of electrons with high-intensity, well-controlled polarization. The technology has enabled ancillary facilities to be created. The CEBAF facility is used by an international user community of more than 1200 physicists for a program of exploration and study of nuclear, hadronic matter, the strong interaction and quantum chromodynamics. Additionally, the exceptional quality of the beams facilitates studies of the fundamental symmetries of nature, which complement those of atomic physics on the one hand and of high-energy particle physics on the other. The facility is in the midst of a project to double the energy of the facility and to enhance and expand its experimental facilities. Studies are also pursued with a Free-Electron Laser produced by an energy-recovering linear accelerator.

  11. High Performance Outdoor Lighting Accelerator

    Broader source: Energy.gov [DOE]

    Hosted by the U.S. Department of Energy (DOE)’s Weatherization and Intergovernmental Programs Office (WIPO), this webinar covered the expansion of the Better Buildings platform to include the newest initiative for the public sector: the High Performance Outdoor Lighting Accelerator (HPOLA).

  12. Controllable giant dielectric constant in AlO{sub x}/TiO{sub y} nanolaminates.

    SciTech Connect (OSTI)

    Li, W.; Chen, Z.; Premnath, R. N.; Kabius, B.; Auciello, O. (Center for Nanoscale Materials); ( MSD); (Univ. of Puerto Rico)

    2011-01-01T23:59:59.000Z

    Dielectric materials exhibiting high dielectric constants play critical roles in a wide range of applications from microchip energy storage embedded capacitors for implantable biomedical devices to energy storage capacitors for a new generation of renewable energy generation/storage systems. Instead of searching for new materials, we demonstrate that giant dielectric constants can be achieved by integrating two simple oxides with low dielectric constants into nanolaminate structures. In addition, the obtained dielectric constant values are highly tunable by manipulating the sub-layer thicknesses of the component oxides to control the number of interfaces and oxygen redistribution. The work reported here opens a new pathway for the design and development of high dielectric constant materials based on the nanolaminate concept.

  13. A Software System for Modeling and Controlling Accelerator Physics Parameters at the Advanced Light Source

    E-Print Network [OSTI]

    Schachinger, L.C.

    2011-01-01T23:59:59.000Z

    and Controlling Accelerator Physics Parameters at theLight Source for accelerator physics studies and accelerator

  14. accelerator driven radioactive: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    T. Sasa; K. Tsujimoto; H. Takano 3 Developments in laser-driven plasma accelerators CERN Preprints Summary: Laser-driven plasma accelerators provide acceleration gradients...

  15. LASER-PLASMA-ACCELERATOR-BASED GAMMA GAMMA COLLIDERS

    E-Print Network [OSTI]

    Schroeder, C. B.

    2010-01-01T23:59:59.000Z

    LASER-PLASMA-ACCELERATOR-BASED ?? COLLIDERS ? C. B.linear col- lider based on laser-plasma-accelerators arediscussed, and a laser-plasma-accelerator-based gamma-

  16. Cell Component Accelerated Stress Test Protocols for PEM Fuel...

    Broader source: Energy.gov (indexed) [DOE]

    Cell Component Accelerated Stress Test Protocols for PEM Fuel Cells Cell Component Accelerated Stress Test Protocols for PEM Fuel Cells Accelerated Stress Test Protocols for PEM...

  17. Advanced Computing Tools and Models for Accelerator Physics

    E-Print Network [OSTI]

    Ryne, Robert D.

    2008-01-01T23:59:59.000Z

    TOOLS AND MODELS FOR ACCELERATOR PHYSICS * Robert D. Ryne,computing tools for accelerator physics. Following anscale computing in accelerator physics. INTRODUCTION To

  18. accelerate positional cloning: Topics by E-print Network

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    of velocity is acceleration (i DeTurck, Dennis 2 LTB universes as alternatives to dark energy: does positive averaged acceleration imply positive cosmic acceleration?...

  19. Time-dependent dielectric breakdown measurements of porous organosilicate glass using mercury and solid metal probes

    SciTech Connect (OSTI)

    Pei, Dongfei; Nichols, Michael T.; Shohet, J. Leon, E-mail: shohet@engr.wisc.edu [Plasma Processing and Technology Laboratory, Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); King, Sean W.; Clarke, James S. [Intel Corporation, Hillsboro, Oregon 97124 (United States); Nishi, Yoshio [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States)

    2014-09-01T23:59:59.000Z

    Time-dependent dielectric breakdown (TDDB) is one of the major concerns for low-k dielectric materials. During plasma processing, low-k dielectrics are subjected to vacuum ultraviolet photon radiation and charged-particle bombardment. To examine the change of TDDB properties, time-to-breakdown measurements are made to porous SiCOH before and after plasma exposure. Significant discrepancies between mercury and solid-metal probes are observed and have been shown to be attributed to mercury diffusion into the dielectric porosities.

  20. The development of microstrip to dielectric waveguide transitions and beam steering techniques

    E-Print Network [OSTI]

    Miller, Jeffrey Allen

    1989-01-01T23:59:59.000Z

    Dielectric waveguide tapered in y dimension. . 8 Dielectric waveguide tapered in x and y dimensions. 20 9 Transition loss for 521 mm of dielectric waveguide and two standard horn transitions. 22 10 Two new transitions connected simultaneously. 11 Time.... 56 GHz for one transition, one horn, and 521 mm of dielectric waveguide 25 14 Diamond shaped 1'oil. 26 15 Foil shapes derived from narrowing width D. 27 16 Transition loss for two transitions and 521 mm of waveguide with foil widths: a) 15. 88 mm...

  1. Relationship between orientation factor of lead zirconate titanate nanowires and dielectric permittivity of nanocomposites

    SciTech Connect (OSTI)

    Tang, Haixiong, E-mail: htang15@ufl.edu, E-mail: hsodano@ufl.edu [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States)] [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Malakooti, Mohammad H. [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611 (United States)] [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611 (United States); Sodano, Henry A., E-mail: htang15@ufl.edu, E-mail: hsodano@ufl.edu [Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611 (United States); Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida 32611 (United States)

    2013-11-25T23:59:59.000Z

    The relationship between the orientation of lead zirconate titanate (PZT) nanowires dispersed in nanocomposites and the resulting dielectric constants are quantified. The orientation of the PZT nanowires embedded in a polymer matrix is controlled by varying the draw ratio and subsequently quantified using Herman's Orientation Factor. Consequently, it is demonstrated that the dielectric constants of nanocomposites are improved by increasing the orientation factor of the PZT nanowires. This technique is proposed to improve the dielectric constant of the nanocomposites without the need for additional filler volume fraction since the nanocomposites are utilized in a wide range of high dielectric permittivity electronic components.

  2. E-Print Network 3.0 - atmospheric pressure dielectric Sample...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    C. Elissalde, S. Mornet and M. Maglione Summary: to process bulk composites having supercapacitor features with low dielectric losses and temperature... stability. The silica shell...

  3. E-Print Network 3.0 - altering dielectric structure Sample Search...

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    C. Elissalde, S. Mornet and M. Maglione Summary: to process bulk composites having supercapacitor features with low dielectric losses and temperature... stability. The silica shell...

  4. Chemical vapor deposition of organosilicon composite thin films for porous low-k dielectrics

    E-Print Network [OSTI]

    Ross, April Denise, 1977-

    2005-01-01T23:59:59.000Z

    Pulsed plasma enhanced chemical vapor deposition has produced organosilicon thin films with the potential use as low dielectric constant interconnect materials in microelectronic circuits. Both diethylsilane and ...

  5. CAS - CERN Accelerator School: Advanced Accelerator Physics Course

    E-Print Network [OSTI]

    2014-01-01T23:59:59.000Z

    This report presents the proceedings of the Course on Advanced Accelerator Physics organized by the CERN Accelerator School. The course was held in Trondheim, Norway from 18 to 29 August 2013, in collaboration with the Norwegian University of Science and Technology. Its syllabus was based on previous courses and in particular on the course held in Berlin 2003 whose proceedings were published as CERN Yellow Report CERN- 2006-002. The field has seen significant advances in recent years and some topics were presented in a new way and other topics were added. The lectures were supplemented with tutorials on key topics and 14 hours of hands on courses on Optics Design and Corrections, RF Measurement Techniques and Beam Instrumentation and Diagnostics. These courses are a key element of the Advanced Level Course.

  6. Accelerator on a Chip: How It Works

    SciTech Connect (OSTI)

    None

    2014-06-30T23:59:59.000Z

    In an advance that could dramatically shrink particle accelerators for science and medicine, researchers used a laser to accelerate electrons at a rate 10 times higher than conventional technology in a nanostructured glass chip smaller than a grain of rice.

  7. FPGA ACCELERATION OF MOLECULAR DYNAMICS SIMULATIONS

    E-Print Network [OSTI]

    Herbordt, Martin

    ' & $ % FPGA ACCELERATION OF MOLECULAR DYNAMICS SIMULATIONS YONGFENG GU Dissertation submitted;BOSTON UNIVERSITY COLLEGE OF ENGINEERING Dissertation FPGA ACCELERATION OF MOLECULAR DYNAMICS SIMULATIONS DYNAMICS SIMULATIONS (Order No. ) YONGFENG GU Boston University, College of Engineering, 2008 Major

  8. MANUFACTURING ACCELERATING THE INCORPORATION OF MATERIALS

    E-Print Network [OSTI]

    Magee, Joseph W.

    MANUFACTURING ACCELERATING THE INCORPORATION OF MATERIALS ADVANCES INTO MANUFACTURING PROCESSES NATIONAL NEED The proposed topic "Accelerating the Incorporation of Materials Advances into Manufacturing organizations, leading researchers from academic institutions, and others. Materials performance is often

  9. CRAD, Engineering - Idaho Accelerated Retrieval Project Phase...

    Broader source: Energy.gov (indexed) [DOE]

    Engineering - Idaho Accelerated Retrieval Project Phase II CRAD, Engineering - Idaho Accelerated Retrieval Project Phase II February 2006 A section of Appendix C to DOE G 226.1-2...

  10. HIGH-FIELD SUPERCONDUCTING ACCELERATOR MAGNETS

    E-Print Network [OSTI]

    Taylor, C.

    2011-01-01T23:59:59.000Z

    D. C. 'Niobium-Titanium Superconducting Material s ', in S.14, 1982 HIGH-FIELD SUPERCONDUCTING ACCELERATOR MAGNETS C.SUMAG-68 HIGH-FIELD SUPERCONDUCTING ACCELERATOR MAGNETS* C.

  11. Physics 321 Accelerating Reference Frames II

    E-Print Network [OSTI]

    Hart, Gus

    Physics 321 Hour 25 Accelerating Reference Frames II Consider an accelerating train car Proof 0 and S is a frame rotating with angular velocity . Examples Handout rotation.nb #12;Physics 321 Hour 26 Accelerating Reference Frames III Velocities in Rotating Frames in S0 basis in S' basis In S' basis in S0 basis

  12. Voltage regulation in linear induction accelerators

    DOE Patents [OSTI]

    Parsons, William M. (Santa Fe, NM)

    1992-01-01T23:59:59.000Z

    Improvement in voltage regulation in a Linear Induction Accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance.

  13. Voltage regulation in linear induction accelerators

    DOE Patents [OSTI]

    Parsons, W.M.

    1992-12-29T23:59:59.000Z

    Improvement in voltage regulation in a linear induction accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core is disclosed. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance. 4 figs.

  14. US LHC Accelerator Research Program For the BNL-FNAL-LBNL LHC Accelerator Collaboration

    E-Print Network [OSTI]

    Large Hadron Collider Program

    instruments that will improve the operation of the LHC and help us perform accelerator physics experiments science. · Perform accelerator physics studies and advanced magnet R&D that will result in the IR designsUS LHC Accelerator Research Program Jim Strait For the BNL-FNAL-LBNL LHC Accelerator Collaboration

  15. Industrial applications of electron accelerators

    E-Print Network [OSTI]

    Cleland, M R

    2006-01-01T23:59:59.000Z

    This paper addresses the industrial applications of electron accelerators for modifying the physical, chemical or biological properties of materials and commercial products by treatment with ionizing radiation. Many beneficial effects can be obtained with these methods, which are known as radiation processing. The earliest practical applications occurred during the 1950s, and the business of radiation processing has been expanding since that time. The most prevalent applications are the modification of many different plastic and rubber products and the sterilization of single-use medical devices. Emerging applications are the pasteurization and preservation of foods and the treatment of toxic industrial wastes. Industrial accelerators can now provide electron energies greater than 10 MeV and average beam powers as high as 700 kW. The availability of high-energy, high-power electron beams is stimulating interest in the use of X-rays (bremsstrahlung) as an alternative to gamma rays from radioactive nuclides.

  16. Accelerated expansion from cosmological holography

    E-Print Network [OSTI]

    van Putten, Maurice H P M

    2015-01-01T23:59:59.000Z

    It is shown that holographic cosmology implies an evolving Hubble radius $c^{-1}\\dot{R}_H = -1 + 3\\Omega_m$ in the presence of a dimensionless matter density $\\Omega_m$ scaled to the closure density $3H^2/8\\pi G$, where $c$ denotes the velocity of light and $H$ and $G$ denote the Hubble parameter and Newton's constant. It reveals a dynamical dark energy and a sixfold increase in gravitational attraction to matter on the scale of the Hubble acceleration. It reproduces the transition redshift $z_t\\simeq 0.4$ to the present epoch of accelerated expansion and is consistent with $(q_0,(dq/dz)_0)$ of the deceleration parameter $q(z)=q_0+(dq/dz)_0z$ observed in Type Ia supernovae.

  17. Compensation Techniques in Accelerator Physics

    SciTech Connect (OSTI)

    Hisham Kamal Sayed

    2011-05-31T23:59:59.000Z

    Accelerator physics is one of the most diverse multidisciplinary fields of physics, wherein the dynamics of particle beams is studied. It takes more than the understanding of basic electromagnetic interactions to be able to predict the beam dynamics, and to be able to develop new techniques to produce, maintain, and deliver high quality beams for different applications. In this work, some basic theory regarding particle beam dynamics in accelerators will be presented. This basic theory, along with applying state of the art techniques in beam dynamics will be used in this dissertation to study and solve accelerator physics problems. Two problems involving compensation are studied in the context of the MEIC (Medium Energy Electron Ion Collider) project at Jefferson Laboratory. Several chromaticity (the energy dependence of the particle tune) compensation methods are evaluated numerically and deployed in a figure eight ring designed for the electrons in the collider. Furthermore, transverse coupling optics have been developed to compensate the coupling introduced by the spin rotators in the MEIC electron ring design.

  18. Analytical tools in accelerator physics

    SciTech Connect (OSTI)

    Litvinenko, V.N.

    2010-09-01T23:59:59.000Z

    This paper is a sub-set of my lectures presented in the Accelerator Physics course (USPAS, Santa Rosa, California, January 14-25, 2008). It is based on my notes I wrote during period from 1976 to 1979 in Novosibirsk. Only few copies (in Russian) were distributed to my colleagues in Novosibirsk Institute of Nuclear Physics. The goal of these notes is a complete description starting from the arbitrary reference orbit, explicit expressions for 4-potential and accelerator Hamiltonian and finishing with parameterization with action and angle variables. To a large degree follow logic developed in Theory of Cyclic Particle Accelerators by A.A.Kolmensky and A.N.Lebedev [Kolomensky], but going beyond the book in a number of directions. One of unusual feature is these notes use of matrix function and Sylvester formula for calculating matrices of arbitrary elements. Teaching the USPAS course motivated me to translate significant part of my notes into the English. I also included some introductory materials following Classical Theory of Fields by L.D. Landau and E.M. Liftsitz [Landau]. A large number of short notes covering various techniques are placed in the Appendices.

  19. Generation and Characterization of Electron Bunches with Ramped Current Profiles in a Dual-Frequency Superconducting Linear Accelerator

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Piot, P; Fermilab; Behrens, C; Gerth, C; Dohlus, M; Lemery, F; Mihalcea, D; Stoltz, P; Vogt, M

    2011-09-07T23:59:59.000Z

    We report on the successful experimental generation of electron bunches with ramped current profiles. The technique relies on impressing nonlinear correlations in the longitudinal phase space using a superconducing radiofrequency linear accelerator operating at two frequencies and a current-enhancing dispersive section. The produced {approx} 700-MeV bunches have peak currents of the order of a kilo-Ampere. Data taken for various accelerator settings demonstrate the versatility of the method and in particular its ability to produce current profiles that have a quasi-linear dependency on the longitudinal (temporal) coordinate. The measured bunch parameters are shown, via numerical simulations, to produce gigavolt-per-meter peak acceleratingmore »electric fields with transformer ratios larger than 2 in dielectric-lined waveguides.« less

  20. Accelerator Technology Division progress report, FY 1992

    SciTech Connect (OSTI)

    Schriber, S.O.; Hardekopf, R.A.; Heighway, E.A.

    1993-07-01T23:59:59.000Z

    This report briefly discusses the following topics: The Ground Test Accelerator Program; Defense Free-Electron Lasers; AXY Programs; A Next Generation High-Power Neutron-Scattering Facility; JAERI OMEGA Project and Intense Neutron Sources for Materials Testing; Advanced Free-Electron Laser Initiative; Superconducting Supercollider; The High-Power Microwave (HPM) Program; Neutral Particle Beam (NPB) Power Systems Highlights; Industrial Partnering; Accelerator Physics and Special Projects; Magnetic Optics and Beam Diagnostics; Accelerator Design and Engineering; Radio-Frequency Technology; Accelerator Theory and Free-Electron Laser Technology; Accelerator Controls and Automation; Very High-Power Microwave Sources and Effects; and GTA Installation, Commissioning, and Operations.

  1. Dielectric relaxation of thin films of polyamide random copolymers

    E-Print Network [OSTI]

    Natsumi Taniguchi; Koji Fukao; Paul Sotta; Didier R. Long

    2015-02-13T23:59:59.000Z

    We investigate the relaxation behavior of thin films of a polyamide random copolymer, PA66/6I, with various film thicknesses using dielectric relaxation spectroscopy. Two dielectric signals are observed at high temperatures, the $\\alpha$-process and the relaxation process due to electrode polarization (the EP-process), in addition to the conductivity component. The relaxation time of the EP-process has a Vogel-Fulcher-Tammann type of temperature dependence, and the glass transition temperature, $T_{\\rm g}$, evaluated from the EP-process agrees very well with the $T_{\\rm g}$ determined from the thermal measurements. The fragility index derived from the EP-process increases with decreasing film thickness. The relaxation time and the dielectric relaxation strength of the EP-process are described by a linear function of the film thickness $d$ for large values of $d$, which can be regarded as experimental evidence for the validity of attributing the observed signal to the EP-process. Furthermore, there is distinct deviation from this linear law for thicknesses smaller than a critical value. This deviation observed in thinner films is associated with an increase in the mobility and/or diffusion constant of the charge carriers responsible for the EP-process. The $\\alpha$-process is located in a high frequency region than the EP-process at high temperatures, but merges with the EP-process at lower temperatures near the glass transition region. The thickness dependence of the relaxation time of the $\\alpha$-process is different from that of the EP-process. This suggests that there is decoupling between the segmental motion of the polymers and the translational motion of the charge carriers in confinement.

  2. Focus Research Areas 1. Fundamental Accelerator Physics: Theory

    E-Print Network [OSTI]

    Kemner, Ken

    Focus Research Areas 1. Fundamental Accelerator Physics: Theory Importance Accelerator physics aspects. Pursuit of fundamental accelerator physics in this sense has contributed significantly to the advance of the accelerator physics knowledgebase during the last several decades, clarifying

  3. Multiphoton Ionization in Dielectrics: Comparison of Circular and Linear Polarization

    SciTech Connect (OSTI)

    Temnov, V. V. [Institut fuer Experimentelle Physik, Universitaet Duisburg-Essen, 47048 Duisburg (Germany); Experimentelle Physik IIb, Universitaet Dortmund, D-44221 Dortmund (Germany); Sokolowski-Tinten, K.; Zhou, P.; El-Khamhawy, A.; Linde, D. von der [Institut fuer Experimentelle Physik, Universitaet Duisburg-Essen, 47048 Duisburg (Germany)

    2006-12-08T23:59:59.000Z

    Ionization mechanisms in bulk dielectrics irradiated by single intense 50-fs-laser pulses are investigated by ultrafast time-resolved imaging interferometry. Polarization-sensitive 6-photon ionization is shown to be the dominant ionization mechanism in fused silica and sapphire at intensities around 10 TW/cm{sup 2}. For both materials the cross sections of 6-photon ionization are found to be significantly higher for linear polarization than for circular. Our experimental results corroborate an earlier theoretical prediction on the dominance of linear polarization in high-order multiphoton ionization.

  4. FFAG ACCELERATOR PROTON DRIVER FOR NEUTRINO FACTORY.

    SciTech Connect (OSTI)

    RUGGIERO, A.

    2005-06-21T23:59:59.000Z

    This paper is the summary of a conceptual study of a Proton Driver for Neutrino Factory based on the use of a Fixed-Field Alternating-Gradient (FFAG) Accelerator. The required proton energy range for an optimum neutrino production is 5 to 12 GeV. This can be accomplished with a group of three concentric rings each with 807 m circumference [1]. FFAG Accelerators [2] have the capability to accelerate charged particles over a large momentum range ({+-}30-50%) and the feature of constant bending and focusing fields. Particles can be accelerated very fast at the rate given by the accelerating field of RF cavities placed in proper locations between magnets. The performance of FFAG accelerators is to be placed between that of Super-Conducting Linear Accelerators (SCL), with which they share the fast acceleration rate, and Rapid-Cycling Synchrotrons (RCS), as they allow the beam to re-circulate over fewer revolutions. Brookhaven National Laboratory is involved in the study of feasibility of FFAG Accelerators to accelerate intense beams of protons in the GeV energy range for a variety of applications the most important of which is the Upgrade of the Alternating Gradient Synchrotron (AGS) with a new FFAG injector [3] accelerating from 400 MeV to 1.5 GeV. The ring would be housed in the AGS tunnel and has henceforth a circumference of 807 m.

  5. Particle acceleration efficiencies in astrophysical shear flows

    E-Print Network [OSTI]

    F. M. Rieger; P. Duffy

    2005-02-04T23:59:59.000Z

    The acceleration of energetic particles in astrophysical shear flows is analyzed. We show that in the presence of a non-relativistic gradual velocity shear, power law particle momentum distributions $f(p) \\propto p^{-(3+\\alpha)}$ may be generated, assuming a momentum-dependent scattering time $\\tau \\propto p^{\\alpha}$, with $\\alpha > 0$. We consider possible acceleration sites in astrophysical jets and study the conditions for efficient acceleration. It is shown, for example, that in the presence of a gradual shear flow and a gyro-dependent particle mean free path, synchrotron radiation losses no longer stop the acceleration once it has started to work efficiently. This suggests that shear acceleration may naturally account for a second, non-thermal population of energetic particles in addition to a shock-accelerated one. The possible relevance of shear acceleration is briefly discussed with reference to the relativistic jet in the quasar 3C 273.

  6. High Performance Computing in Accelerator Science: Past Successes. Future Challenges

    E-Print Network [OSTI]

    Ryne, R.

    2013-01-01T23:59:59.000Z

    High Performance Computing in Accelerator Science: PastAC02- 05CH11231. High Performance Computing in Accelerator

  7. Community Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies

    SciTech Connect (OSTI)

    Spentzouris, P.; /Fermilab; Cary, J.; /Tech-X, Boulder; McInnes, L.C.; /Argonne; Mori, W.; /UCLA; Ng, C.; /SLAC; Ng, E.; Ryne, R.; /LBL, Berkeley

    2011-11-14T23:59:59.000Z

    The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors. ComPASS is in the first year of executing its plan to develop the next-generation HPC accelerator modeling tools. ComPASS aims to develop an integrated simulation environment that will utilize existing and new accelerator physics modules with petascale capabilities, by employing modern computing and solver technologies. The ComPASS vision is to deliver to accelerator scientists a virtual accelerator and virtual prototyping modeling environment, with the necessary multiphysics, multiscale capabilities. The plan for this development includes delivering accelerator modeling applications appropriate for each stage of the ComPASS software evolution. Such applications are already being used to address challenging problems in accelerator design and optimization. The ComPASS organization for software development and applications accounts for the natural domain areas (beam dynamics, electromagnetics, and advanced acceleration), and all areas depend on the enabling technologies activities, such as solvers and component technology, to deliver the desired performance and integrated simulation environment. The ComPASS applications focus on computationally challenging problems important for design or performance optimization to all major HEP, NP, and BES accelerator facilities. With the cost and complexity of particle accelerators rising, the use of computation to optimize their designs and find improved operating regimes becomes essential, potentially leading to significant cost savings with modest investment.

  8. Fermilab | Science | Particle Accelerators | LHC and Future Accelerators

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742EnergyOnItem NotEnergy,ARMFormsGasReleaseSpeechesHall A ThisFermilab's Accelerator Complex

  9. Surface plasmon routing in dielectric-loaded surface plasmon polariton waveguides

    E-Print Network [OSTI]

    Grandidier, Jonathan

    Surface plasmon routing in dielectric-loaded surface plasmon polariton waveguides J. Grandidier, S ABSTRACT Waveguiding by dielectric-loaded surface plasmon-polaritons (DLSPP) structures are numerically waveguide parameters such as width and thickness on the properties of the surface plasmon guided modes

  10. Crack Detection in Dielectric Structures by a Linear Sampling , M. Brignone2

    E-Print Network [OSTI]

    Piana, Michele

    Crack Detection in Dielectric Structures by a Linear Sampling Approach G. Bozza1 , M. Brignone2 , M for the detection of cracks and defects inside dielectric structures is presented. The proposed algorithm is based of the approach is assessed by means of numerical simulations. 1. Introduction The imaging community

  11. Dielectric properties of liquid ethanol. A computer simulation study Leonor Saiz

    E-Print Network [OSTI]

    Saiz, Leonor

    Dielectric properties of liquid ethanol. A computer simulation study Leonor Saiz Departament de Fi Static and dynamic dielectric properties of liquid ethanol have been studied as a function of the wave, but in the case of ethanol, the latter are restricted to the microwave region of the spectra6 and to the infrared

  12. An Array-Based Test Circuit for Fully Automated Gate Dielectric Breakdown Characterization

    E-Print Network [OSTI]

    Kim, Chris H.

    An Array-Based Test Circuit for Fully Automated Gate Dielectric Breakdown Characterization John for efficiently characterizing gate dielectric breakdown. Such a design is highly beneficial when studying this statistical process, where up to thousands of samples are needed to create an accurate time to breakdown

  13. Phase-field model for dielectric breakdown in solids Krishna Chaitanya Pitike and Wei Hong*

    E-Print Network [OSTI]

    Hong, Wei

    breakdown strength and sample thickness. Finally, the effect of the layered structure in a breakdown1 Phase-field model for dielectric breakdown in solids Krishna Chaitanya Pitike and Wei Hong dielectric breakdown and fracture of solids, this paper develops a phase field model for the electric damage

  14. Lanthanum silicate gate dielectric stacks with subnanometer equivalent oxide thickness utilizing an interfacial silica consumption reaction

    E-Print Network [OSTI]

    Garfunkel, Eric

    Lanthanum silicate gate dielectric stacks with subnanometer equivalent oxide thickness utilizing-8087 Received 13 April 2005; accepted 6 June 2005; published online 26 July 2005 A silicate reaction between process route to interface elimination, while producing a silicate dielectric with a higher temperature

  15. Molecular Caulk: A Pore Sealing Technology for Ultra-low k Dielectrics Jay J. Senkevich1

    E-Print Network [OSTI]

    Wang, Gwo-Ching

    Molecular Caulk: A Pore Sealing Technology for Ultra-low k Dielectrics Jay J. Senkevich1 Washington Ave., Albany, NY 12222 Abstract Much effort has been undertaken to develop high performance ultra-low k ( 2.2) (ULK) dielectrics to improve the interconnect speed of ultra-large scale integrated devices

  16. Towards a deployable satellite gripper based on multisegment dielectric elastomer minimum energy

    E-Print Network [OSTI]

    Floreano, Dario

    Towards a deployable satellite gripper based on multisegment dielectric elastomer minimum energy dielectric elastomer minimum energy structures O. A. Araromi*a , I. Gavrilovichb , J. Shintakea , S. Rosseta , H. R. Sheaa a Microsystems For Space Technologies Laboratory, �cole Polytechnique Fédérale de

  17. Zirconium-doped tantalum oxide high-k gate dielectric films

    E-Print Network [OSTI]

    Tewg, Jun-Yen

    2005-02-17T23:59:59.000Z

    A new high-k dielectric material, i.e., zirconium-doped tantalum oxide (Zr-doped TaOx), in the form of a sputter-deposited thin film with a thickness range of 5-100 nm, has been studied. Important applications of this new dielectric material include...

  18. A Chip antenna with Magneto-Dielectric material Y.S. Shin(1)

    E-Print Network [OSTI]

    Park, Seong-Ook

    are measured in order to get its characteristics. Two materials, polycarbonate and magneto-dielectric material that the ferrite powder 10% add to the polycarbonate, are applied to the antenna as a supporter. Fig.3 and 4show of polycarbonate because of adding the ferrite powder. From Fig.4, when the magneto-dielectric supporter is applied

  19. Implicit solvation based on generalized Born theory in different dielectric environments

    E-Print Network [OSTI]

    Feig, Michael; Im, Wonpil; Brooks III, Charles L

    2004-01-01T23:59:59.000Z

    this new approach can be applied for the calculation of transfer free energies from vacuum to a given external dielectric for a system with an internal dielectric larger than one. This has not been possible with standard GB theory but is relevant when...

  20. Graphene field-effect transistors based on boron nitride gate dielectrics Inanc Meric1

    E-Print Network [OSTI]

    Shepard, Kenneth

    Graphene field-effect transistors based on boron nitride gate dielectrics Inanc Meric1 , Cory Dean1, 10027 Tel: (212) 854-2529, Fax: (212) 932-9421, Email: shepard@ee.columbia.edu Abstract Graphene field of graphene, as the gate dielectric. The devices ex- hibit mobility values exceeding 10,000 cm2 /V

  1. Leakage current and dielectric breakdown behavior in annealed SiO2 aerogel films

    E-Print Network [OSTI]

    Jo, Moon-Ho

    Leakage current and dielectric breakdown behavior in annealed SiO2 aerogel films Moon-Ho Jo behavior in annealed SiO2 aerogel films for intermetal dielectric applications was investigated in a metal­insulator­semiconductor structure. SiO2 aerogel films with porosities of 70% exhibited Poole­Frenkel conduction both before

  2. Terahertz dielectric properties of high-resistivity single-crystal ZnO Abul K. Azad

    E-Print Network [OSTI]

    experimentally that ZnO shows significantly higher radiation hardness than Si, GaN, and GaAs.5 Additionally absorption, and dielectric function are well fit by the pseudo-harmonic model of dielectric response. In addition, from the extrapolation of the experimental results, we show that the absorption is dominated

  3. Use of a hard mask for formation of gate and dielectric via nanofilament field emission devices

    DOE Patents [OSTI]

    Morse, Jeffrey D. (Martinez, CA); Contolini, Robert J. (Lake Oswego, OR)

    2001-01-01T23:59:59.000Z

    A process for fabricating a nanofilament field emission device in which a via in a dielectric layer is self-aligned to gate metal via structure located on top of the dielectric layer. By the use of a hard mask layer located on top of the gate metal layer, inert to the etch chemistry for the gate metal layer, and in which a via is formed by the pattern from etched nuclear tracks in a trackable material, a via is formed by the hard mask will eliminate any erosion of the gate metal layer during the dielectric via etch. Also, the hard mask layer will protect the gate metal layer while the gate structure is etched back from the edge of the dielectric via, if such is desired. This method provides more tolerance for the electroplating of a nanofilament in the dielectric via and sharpening of the nanofilament.

  4. Problems in the theory of thermal Casimir force between dielectrics and semiconductors

    E-Print Network [OSTI]

    G. L. Klimchitskaya; B. Geyer

    2008-02-26T23:59:59.000Z

    The application of the Lifshitz theory to describe the thermal Casimir force between dielectrics and semiconductors is considered. It is shown that for all true dielectrics (i.e., for all materials having zero conductivity at zero temperature) the inclusion of a nonzero conductivity arising at nonzero temperature into the model of dielectric response leads to the violation of the Nernst heat theorem. This result refers equally to simple insulators, intrinsic semiconductors, Mott-Hubbard dielectrics and doped semiconductors with doping concentration below a critical value. We demonstrate that in the insulator-metal transition the Casimir free energy changes abruptly irrespective of whether the conductivity changes continuously or discontinuously. The application of the Lifshitz formula to polar dielectrics results in large thermal correction that is linear in temperature. A rule is formulated on how to apply the Lifshitz theory to real materials in agreement with thermodynamics and experiment.

  5. Characteristic impedance and capacitance analysis of Blumlein type pulse forming line of accelerator based on tape helix

    SciTech Connect (OSTI)

    Zhang Yu; Liu Jinliang; Fan Xuliang; Zhang Hongbo; Wang Shiwen; Feng Jiahuai [College of Opto-electronic Science and Engineering, National University of Defense Technology, Changsha, 410073 (China)

    2011-10-15T23:59:59.000Z

    In this paper, the electromagnetic dispersion theory and the classic telegraph equations were combined to calculate the important parameters of the helical Blumlein pulse forming line (BPFL) of accelerator based on tape helix. In the work band of the BPFL at several hundred ns range, electromagnetic dispersion characteristics were almost determined by the zeroth harmonic. In order to testify the dispersion theory of BPFL in this paper, filling dielectrics, such as de-ionized water, transformer oil, and air were employed in the helical BPFL, respectively. Parameters such as capacitance, inductance, characteristic impedance, and pulse duration of the BPFL were calculated. Effects of dispersion on these parameters were analyzed. Circuit simulation and electromagnetic simulation were carried out to prove these parameters of BPFL filled with these three kinds of dielectrics, respectively. The accelerator system was set up, and experimental results also corresponded to the theoretical calculations. The average theoretical errors of impedances and pulse durations were 3.5% and 3.4%, respectively, which proved the electromagnetic dispersion analyses in this paper.

  6. Using Dielectric Losses to De-Ice Power Transmission Lines with 100 kHz High-Voltage

    E-Print Network [OSTI]

    Using Dielectric Losses to De-Ice Power Transmission Lines with 100 kHz High-Voltage Excitation J DIELECTRIC LOSSES TO DE-ICE POWER TRANSMISSION LINES . . . 1 Using Dielectric Losses to De-Ice Power Transmission Lines with 100 kHz High-Voltage Excitation Joshua D. McCurdy, Charles R. Sullivan and Victor F

  7. Enhancement of non-resonant dielectric cloaks using anisotropic composites

    SciTech Connect (OSTI)

    Takezawa, Akihiro, E-mail: akihiro@hiroshima-u.ac.jp; Kitamura, Mitsuru [Division of Mechanical Systems and Applied Mechanics, Institute of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima (Japan)] [Division of Mechanical Systems and Applied Mechanics, Institute of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima (Japan)

    2014-01-15T23:59:59.000Z

    Cloaking techniques conceal objects by controlling the flow of electromagnetic waves to minimize scattering. Herein, the effectiveness of homogenized anisotropic materials in non-resonant dielectric multilayer cloaking is studied. Because existing multilayer cloaking by isotropic materials can be regarded as homogenous anisotropic cloaking from a macroscopic view, anisotropic materials can be efficiently designed through optimization of their physical properties. Anisotropic properties can be realized in two-phase composites if the physical properties of the material are within appropriate bounds. The optimized anisotropic physical properties are identified by a numerical optimization technique based on a full-wave simulation using the finite element method. The cloaking performance measured by the total scattering width is improved by about 2.8% and 25% in eight- and three-layer cylindrical cloaking materials, respectively, compared with multilayer cloaking by isotropic materials. In all cloaking examples, the optimized microstructures of the two-phase composites are identified as the simple lamination of two materials, which maximizes the anisotropy. The same performance as published for eight-layer cloaking by isotropic materials is achieved by three-layer cloaking using the anisotropic material. Cloaking with an approximately 50% reduction of total scattering width is achieved even in an octagonal object. Since the cloaking effect can be realized using just a few layers of the laminated anisotropic dielectric composite, this may have an advantage in the mass production of cloaking devices.

  8. Structural and Dielectric Properties of Quartz-Water Interfaces

    SciTech Connect (OSTI)

    Wander, Matthew C.; Clark, Aurora E.

    2008-11-19T23:59:59.000Z

    The structure, orientation, and dielectric of water at the quartz|water interface has been examined under different hydration levels using classical molecular dynamics. The properties of 1H?O/10 Ų, 2H?O/10 Ų, 4H?O/10 Ų, and bulk water on quartz have been benchmarked against experimental data. Structurally, the simulations match existing sum-frequency spectroscopy data, which indicate the existence and orientation of both frozen and loosely bound water on the quartz surface. Good agreement has also been found with existing experimental dielectric data for the 1H?O/10 Ų level of hydration, and a clear difference has been found in the values of ?s = 48, ?| = 48, and ?? = 40 for the first slice of a bulk-water-solid interface and ?s= 30, ?| = 30, and ?? = 10 for that of 1H?O/10 Ų water coverage. Overall there is a fundamental difference in shielding between a single interface and the 1H?O/10 Å2 level of hydration.

  9. Temporal modulation of plasma species in atmospheric dielectric barrier discharges

    SciTech Connect (OSTI)

    Yang, Aijun; Wang, Xiaohua, E-mail: xhw@mail.xjtu.edu.cn, E-mail: mzrong@mail.xjtu.edu.cn; Liu, Dingxin; Rong, Mingzhe, E-mail: xhw@mail.xjtu.edu.cn, E-mail: mzrong@mail.xjtu.edu.cn [Centre for Plasma Biomedicine, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049 (China); Kong, Michael G. [Centre for Plasma Biomedicine, State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049 (China); Frank Reidy Research Center for Bioelectrics, Department of Electrical and Computer Engineering, Old Dominion University, Virginia 23508 (United States); Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia 23529 (United States)

    2014-07-15T23:59:59.000Z

    The atmospheric pressure dielectric barrier discharge in helium is a pulsed discharge in nature and the moment of maximum species densities is almost consistent with peak discharge current density. In this paper, a one-dimensional fluid model is used to investigate the temporal structure of plasma species in an atmospheric He-N{sub 2} dielectric barrier discharge (DBD). It is demonstrated that there exist microsecond delays of the moments of the maximum electron and ion densities from the peak of discharge current density. These time delays are caused by a competition between the electron impact and Penning ionizations, modulated by the N{sub 2} level in the plasma-forming gas. Besides, significant electron wall losses lead to the DBD being more positively charged and, with a distinct temporal separation in the peak electron and cation densities, the plasma is characterized with repetitive bursts of net positive charges. The temporal details of ionic and reactive plasma species may provide a new idea for some biological processes.

  10. The infrared dielectric function of solid para-hydrogen

    E-Print Network [OSTI]

    Kettwich, Cassie; Walker, Mark; Tuntsov, Artem

    2015-01-01T23:59:59.000Z

    We report laboratory measurements of the absorption coefficient of solid para-H2, within the wavelength range from 1 to 16.7 micron, at high spectral resolution. In addition to the narrow rovibrational lines of H2 which are familiar from gas phase spectroscopy, the data manifest double transitions and broad phonon branches that are characteristic specifically of hydrogen in the solid phase. These transitions are of interest because they provide a spectral signature which is independent of the impurity content of the matrix. We have used our data, in combination with a model of the ultraviolet absorptions of the H2 molecule, to construct the dielectric function of solid para-H2 over a broad range of frequencies. Our results will be useful in determining the electromagnetic response of small particles of solid hydrogen. The dielectric function makes it clear that pure H2 dust would contribute to IR extinction predominantly by scattering starlight, rather than absorbing it, and the characteristic IR absorption s...

  11. Mode trap for absorbing transverse modes of an accelerated electron beam

    DOE Patents [OSTI]

    Chojnacki, E.P.

    1994-05-31T23:59:59.000Z

    A mode trap to trap and absorb transverse modes formed by a beam in a linear accelerator includes a waveguide having a multiplicity of electrically conductive (preferably copper) irises and rings, each iris and ring including an aperture, and the irises and rings being stacked in a side-by-side, alternating fashion such that the apertures of the irises and rings are concentrically aligned. An absorbing material layer such as a dielectric is embedded in each iris and ring, and this absorbing material layer encircles, but is circumferentially spaced from its respective aperture. Each iris and ring includes a plurality of circumferentially spaced slots around its aperture and extending radially out toward its absorbing material layer. 9 figs.

  12. Deuterium accelerator experiments for APT.

    SciTech Connect (OSTI)

    Causey, Rion A. (Sandia National Laboratories, Livermore, CA); Hertz, Kristin L. (Sandia National Laboratories, Livermore, CA); Cowgill, Donald F. (Sandia National Laboratories, Livermore, CA)

    2005-08-01T23:59:59.000Z

    Sandia National Laboratories in California initiated an experimental program to determine whether tritium retention in the tube walls and permeation through the tubes into the surrounding coolant water would be a problem for the Accelerator Production of Tritium (APT), and to find ways to mitigate the problem, if it existed. Significant holdup in the tube walls would limit the ability of APT to meet its production goals, and high levels of permeation would require a costly cleanup system for the cooling water. To simulate tritium implantation, a 200 keV accelerator was used to implant deuterium into Al 6061-T and SS3 16L samples at temperatures and particle fluxes appropriate for APT, for times varying between one week and five months. The implanted samples were characterized to determine the deuterium retention and Permeation. During the implantation, the D(d,p)T nuclear reaction was used to monitor the build-up of deuterium in the implant region of the samples. These experiments increased in sophistication, from mono-energetic deuteron implants to multi-energetic deuteron and proton implants, to more accurately reproduce the conditions expected in APT. Micron-thick copper, nickel, and anodized aluminum coatings were applied to the front surface of the samples (inside of the APT walls) in an attempt to lower retention and permeation. The reduction in both retention and permeation produced by the nickel coatings, and the ability to apply them to the inside of the APT tubes, indicate that both nickel-coated Al 6061-T6 and nickel-coated SS3 16L tubes would be effective for use in APT. The results of this work were submitted to the Accelerator Production of Tritium project in document number TPO-E29-Z-TNS-X-00050, APT-MP-01-17.

  13. Determinants of multiple measures of acceleration

    SciTech Connect (OSTI)

    Santini, D.J.; Anderson, J.

    1993-08-01T23:59:59.000Z

    Statistical analyses of the acceleration capability of gasoline vehicles have focused on zero to 97 km/h acceleration rates and have concluded that peak power per kilogram is an appropriate single surrogate for acceleration capability. In this paper, statistical methods are used with data for 107 vehicles tested and reported by Consumers Union for 1986--1988 model years to estimate the determinants of contemporary gasoline vehicle acceleration capability under various conditions, adding new variables to the statistical tests reported by others. Like previous studies, this analysis determined that power and weight provide the most information about acceleration capability. Using a model formulation unlike other studies, this study found that engine displacement also provides statistically significant improvements in explanation of 0-48, 0-97, and 48-97 km/h acceleration times. The coefficients of the equations imply that the use of smaller displacement engines, holding peak power constant, diminishes start-up and 0-97 km/h acceleration capability. A separate equation is estimated to illustrate the effects of advanced engine technologies on displacement, controlling for power. This equation is used in conjunction with the acceleration equations to illustrate a method of estimating performance-equivalent engine substitutions when engine technologies change. Transmission type was important for start-up acceleration, with automatic-transmission-equipped vehicles being significantly slower than stick-shift-equipped vehicles. Fuel injection was found to significantly improve start-up acceleration. Variables proxying aerodynamic-drag effects tended to be significant determinants of acceleration in the higher-speed equations, but not for start-up acceleration. Estimated aerodynamic drag effects indicated that drag slows down 0-97, 48-97, and 72-105 km/h acceleration of pickup trucks and sport utility vehicles more than passenger cars and vans.

  14. Soft coincidence in late acceleration

    SciTech Connect (OSTI)

    Campo, Sergio del [Instituto de Fisica, Pontificia Universidad Catolica de Valparaiso, Avenida Brasil 2950, Casilla 4059, Valparaiso (Chile); Herrera, Ramon [Departamento de Ciencias Fisicas, Universidad Andres Bello, Avenida Republica 273, Santiago (Chile); Pavon, Diego [Departamento de Fisica, Facultad de Ciencias, Universidad Autonoma de Barcelona, 08193 Bellaterra, Barcelona (Spain)

    2005-06-15T23:59:59.000Z

    We study the coincidence problem of late cosmic acceleration by assuming that the present ratio between dark matter and dark energy is a slowly varying function of the scale factor. As the dark energy component we consider two different candidates, first a quintessence scalar field, and then a tachyon field. In either case analytical solutions for the scale factor, the field, and the potential are derived. Both models show a good fit to the recent magnitude-redshift supernovae data. However, the likelihood contours disfavor the tachyon field model as it seems to prefer a excessively high value for the matter component.

  15. Fermilab | Directorate | Fermilab Accelerator Schedules

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField8,Dist.New Mexico Feb. 13, 2013 NAME:JobTimothy Meyer ChiefAccelerator

  16. Accelerating Solutions | ornl.gov

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041cloth DocumentationProducts (VAP) VAP7-0973 1 Introduction In theACME - Accelerated

  17. LTB universes as alternatives to dark energy: does positive averaged acceleration imply positive cosmic acceleration?

    E-Print Network [OSTI]

    Antonio Enea Romano

    2007-01-27T23:59:59.000Z

    We show that positive averaged acceleration obtained in LTB models through spatial averaging can require integration over a region beyond the event horizon of the central observer. We provide an example of a LTB model with positive averaged acceleration in which the luminosity distance does not contain information about the entire spatially averaged region, making the averaged acceleration unobservable. Since the cosmic acceleration is obtained from fitting the observed luminosity distance to a FRW model we conclude that in general a positive averaged acceleration in LTB models does not imply a positive FRW cosmic acceleration.

  18. LTB universes as alternatives to dark energy: does positive averaged acceleration imply positive cosmic acceleration?

    E-Print Network [OSTI]

    Romano, A E

    2006-01-01T23:59:59.000Z

    We show that positive averaged acceleration obtained in LTB models through spatial averaging can require integration over a region beyond the event horizon of the central observer. We provide an example of a LTB model with positive averaged acceleration in which the luminosity distance does not contain information about the entire spatially averaged region, making the averaged acceleration unobservable. Since the cosmic acceleration is obtained from fitting the observed luminosity distance to a FRW model we conclude that in general a positive averaged acceleration in LTB models does not imply a positive FRW cosmic acceleration.

  19. Commnity Petascale Project for Accelerator Science and Simulation: Advancing Computational Science for Future Accelerators and Accelerator Technologies

    SciTech Connect (OSTI)

    Spentzouris, Panagiotis; /Fermilab; Cary, John; /Tech-X, Boulder; Mcinnes, Lois Curfman; /Argonne; Mori, Warren; /UCLA; Ng, Cho; /SLAC; Ng, Esmond; Ryne, Robert; /LBL, Berkeley

    2008-07-01T23:59:59.000Z

    The design and performance optimization of particle accelerators is essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC1 Accelerator Science and Technology project, the SciDAC2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modeling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multi-physics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors.

  20. Commnity Petascale Project for Accelerator Science And Simulation: Advancing Computational Science for Future Accelerators And Accelerator Technologies

    SciTech Connect (OSTI)

    Spentzouris, Panagiotis; /Fermilab; Cary, John; /Tech-X, Boulder; Mcinnes, Lois Curfman; /Argonne; Mori, Warren; /UCLA; Ng, Cho; /SLAC; Ng, Esmond; Ryne, Robert; /LBL, Berkeley

    2011-10-21T23:59:59.000Z

    The design and performance optimization of particle accelerators are essential for the success of the DOE scientific program in the next decade. Particle accelerators are very complex systems whose accurate description involves a large number of degrees of freedom and requires the inclusion of many physics processes. Building on the success of the SciDAC-1 Accelerator Science and Technology project, the SciDAC-2 Community Petascale Project for Accelerator Science and Simulation (ComPASS) is developing a comprehensive set of interoperable components for beam dynamics, electromagnetics, electron cooling, and laser/plasma acceleration modelling. ComPASS is providing accelerator scientists the tools required to enable the necessary accelerator simulation paradigm shift from high-fidelity single physics process modeling (covered under SciDAC1) to high-fidelity multiphysics modeling. Our computational frameworks have been used to model the behavior of a large number of accelerators and accelerator R&D experiments, assisting both their design and performance optimization. As parallel computational applications, the ComPASS codes have been shown to make effective use of thousands of processors.