Sample records for high intensity electron

  1. High Intensity Polarized Electron Gun

    SciTech Connect (OSTI)

    Redwine, Robert

    2012-07-31T23:59:59.000Z

    The goal of the project was to investigate the possibility of building a very high intensity polarized electron gun for the Electron-Ion Collider. This development is crucial for the eRHIC project. The gun implements a large area cathode, ring-shaped laser beam and active cathode cooling. A polarized electron gun chamber with a large area cathode and active cathode cooling has been built and tested. A preparation chamber for cathode activation has been built and initial tests have been performed. Major parts for a load-lock chamber, where cathodes are loaded into the vacuum system, have been manufactured.

  2. High intensity electron cyclotron resonance proton source for low energy high intensity proton accelerator

    SciTech Connect (OSTI)

    Roychowdhury, P.; Chakravarthy, D. P. [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2009-12-15T23:59:59.000Z

    Electron cyclotron resonance (ECR) proton source at 50 keV, 50 mA has been designed, developed, and commissioned for the low energy high intensity proton accelerator (LEHIPA). Plasma characterization of this source has been performed. ECR plasma was generated with 400-1100 W of microwave power at 2.45 GHz, with hydrogen as working gas. Microwave was fed in the plasma chamber through quartz window. Plasma density and temperature was studied under various operating conditions, such as microwave power and gas pressure. Langmuir probe was used for plasma characterization using current voltage variation. The typical hydrogen plasma density and electron temperature measured were 7x10{sup 11} cm{sup -3} and 6 eV, respectively. The total ion beam current of 42 mA was extracted, with three-electrode extraction geometry, at 40 keV of beam energy. The extracted ion current was studied as a function of microwave power and gas pressure. Depending on source pressure and discharge power, more than 30% total gas efficiency was achieved. The optimization of the source is under progress to meet the requirement of long time operation. The source will be used as an injector for continuous wave radio frequency quadrupole, a part of 20 MeV LEHIPA. The required rms normalized emittance of this source is less than 0.2 {pi} mm mrad. The simulated value of normalized emittance is well within this limit and will be measured shortly. This paper presents the study of plasma parameters, first beam results, and the status of ECR proton source.

  3. Electromagnetic cascade in high energy electron, positron, and photon interactions with intense laser pulses

    E-Print Network [OSTI]

    S. S. Bulanov; C. B. Schroeder; E. Esarey; W. P. Leemans

    2013-06-05T23:59:59.000Z

    The interaction of high energy electrons, positrons, and photons with intense laser pulses is studied in head-on collision geometry. It is shown that electrons and/or positrons undergo a cascade-type process involving multiple emissions of photons. These photons can consequently convert into electron-positron pairs. As a result charged particles quickly lose their energy developing an exponentially decaying energy distribution, which suppresses the emission of high energy photons, thus reducing the number of electron-positron pairs being generated. Therefore, this type of interaction suppresses the development of the electromagnetic avalanche-type discharge, i.e., the exponential growth of the number of electrons, positrons, and photons does not occur in the course of interaction. The suppression will occur when 3D effects can be neglected in the transverse particle orbits, i.e., for sufficiently broad laser pulses with intensities that are not too extreme. The final distributions of electrons, positrons, and photons are calculated for the case of a high energy e-beam interacting with a counter-streaming, short intense laser pulse. The energy loss of the e-beam, which requires a self-consistent quantum description, plays an important role in this process, as well as provides a clear experimental observable for the transition from the classical to quantum regime of interaction.

  4. Calculation of synchrotron radiation from high intensity electron beam at eRHIC

    SciTech Connect (OSTI)

    Jing Y.; Chubar, O.; Litvinenko, V.

    2012-05-20T23:59:59.000Z

    The Electron-Relativistic Heavy Ion Collider (eRHIC) at Brookhaven National Lab is an upgrade project for the existing RHIC. A 30 GeV energy recovery linac (ERL) will provide a high charge and high quality electron beam to collide with proton and ion beams. This will improve the luminosity by at least 2 orders of magnitude. The synchrotron radiation (SR) from the bending magnets and strong quadrupoles for such an intense beam could be penetrating the vacuum chamber and producing hazards to electronic devices and undesired background for detectors. In this paper, we calculate the SR spectral intensity, power density distributions and heat load on the chamber wall. We suggest the wall thickness required to stop the SR and estimate spectral characteristics of the residual and scattered background radiation outside the chamber.

  5. A focusable, convergent fast-electron beam from ultra-high-intensity laser-solid interactions

    E-Print Network [OSTI]

    Scott, R H H

    2015-01-01T23:59:59.000Z

    A novel scheme for the creation of a convergent, or focussing, fast-electron beam generated from ultra-high-intensity laser-solid interactions is described. Self-consistent particle-in-cell simulations are used to demonstrate the efficacy of this scheme in two dimensions. It is shown that a beam of fast-electrons of energy 500 keV - 3 MeV propagates within a solid-density plasma, focussing at depth. The depth of focus of the fast-electron beam is controlled via the target dimensions and focussing optics.

  6. Efficient electronic structure calculation for molecular ionization dynamics at high x-ray intensity

    E-Print Network [OSTI]

    Hao, Yajiang; Hanasaki, Kota; Son, Sang-Kil; Santra, Robin

    2015-01-01T23:59:59.000Z

    We present the implementation of an electronic-structure approach dedicated to ionization dynamics of molecules interacting with x-ray free-electron laser (XFEL) pulses. In our scheme, molecular orbitals for molecular core-hole states are represented by linear combination of numerical atomic orbitals that are solutions of corresponding atomic core-hole states. We demonstrate that our scheme efficiently calculates all possible multiple-hole configurations of molecules formed during XFEL pulses. The present method is suitable to investigate x-ray multiphoton multiple ionization dynamics and accompanying nuclear dynamics, providing essential information on the chemical dynamics relevant for high-intensity x-ray imaging.

  7. Production of high intensity electron bunches for the SLAC Linear Collider

    SciTech Connect (OSTI)

    James, M.B.

    1987-08-01T23:59:59.000Z

    This thesis describes the design and performance of a high intensity electron injecfor for the SLAC Linear Collider. Motivation for the collider and the specifications for the injector are discussed. An analytic theory of the bunching and capture of electrons by rf fields is discussed in the limit of low space charge and small signal. The design and performance of SLAC's main injector are described to illustrate a successful application of this theory. The bunching and capture of electrons by rf fields are then discussed in the limit of high space charge and large signal, and a description of the design of the collider injector follows. In the limit of high space charge forces and large rf signals, the beam dynamics are considerably more complex and numerical simulations are required to predict particle motion. A computer code which models the longitudinal dynamics of electrons in the presence of space charge and rf fields is described. The results of the simulations, the resulting collider injector design and the various components which make up the collider injector are described. These include the gun, subharmonic bunchers, traveling-wave buncher and velocity-of-light accelerator section. Finally, the performance of the injector is described including the beam intensity, bunch length, transverse emittance and energy spectrum. While the final operating conditions differ somewaht from the design, the performance of the collider injector is in good agreement with the numerical simulations and meets all of the collider specifications. 28 refs.

  8. Simulation of the Beam Dump for a High Intensity Electron Gun

    E-Print Network [OSTI]

    Doebert, S; Lefevre, T; Pepitone, K

    2014-01-01T23:59:59.000Z

    The CLIC Drive Beam is a high-intensity pulsed electron beam. A test facility for the Drive Beam electron gun will soon be commissioned at CERN. In this contribution we outline the design of a beam dump / Faraday cup capable of resisting the beam’s thermal load. The test facility will operate initially up to 140 keV. At such low energies, the electrons are absorbed very close to the surface of the dump, leading to a large energy deposition density in this thin layer. In order not to damage the dump, the beam must be spread over a large surface. For this reason, a small-angled cone has been chosen. Simulations using Geant4 have been performed to estimate the distribution of energy deposition in the dump. The heat transport both within the electron pulse and between pulses has been modelled using finite element methods to check the resistance of the dump at high repetition rates. In addition, the possibility of using a moveable dump to measure the beam profile and emittance is discussed.

  9. Physics of Neutralization of Intense High-Energy Ion Beam Pulses by Electrons

    SciTech Connect (OSTI)

    Kaganovich, I. D.; Davidson, R. C.; Dorf, M. A.; Startsev, E. A.; Sefkow, A. B.; Lee, E. P.; Friedman, A.

    2010-04-28T23:59:59.000Z

    Neutralization and focusing of intense charged particle beam pulses by electrons forms the basis for a wide range of applications to high energy accelerators and colliders, heavy ion fusion, and astrophysics. For example, for ballistic propagation of intense ion beam pulses, background plasma can be used to effectively neutralize the beam charge and current, so that the self-electric and self- magnetic fields do not affect the ballistic propagation of the beam. From the practical perspective of designing advanced plasma sources for beam neutralization, a robust theory should be able to predict the self-electric and self-magnetic fields during beam propagation through the background plasma. The major scaling relations for the self-electric and self-magnetic fields of intense ion charge bunches propagating through background plasma have been determined taking into account the effects of transients during beam entry into the plasma, the excitation of collective plasma waves, the effects of gas ionization, finite electron temperature, and applied solenoidal and dipole magnetic fields. Accounting for plasma production by gas ionization yields a larger self-magnetic field of the ion beam compared to the case without ionization, and a wake of current density and self-magnetic field perturbations is generated behind the beam pulse. A solenoidal magnetic field can be applied for controlling the beam propagation. Making use of theoretical models and advanced numerical simulations, it is shown that even a small applied magnetic field of about 100G can strongly affect the beam neutralization. It has also been demonstrated that in the presence of an applied magnetic field the ion beam pulse can excite large-amplitude whistler waves, thereby producing a complex structure of self-electric and self-magnetic fields. The presence of an applied solenoidal magnetic field may also cause a strong enhancement of the radial self-electric field of the beam pulse propagating through the background plasma. If controlled, this physical effect can be used for optimized beam transport over long distances.

  10. High-intensity double-pulse X-ray free-electron laser

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

    Marinelli, A.; Ratner, D.; Lutman, A. A.; Turner, J.; Welch, J.; Decker, F. -J.; Loos, H.; Behrens, C.; Gilevich, S.; Miahnahri, A. A.; et al

    2015-03-06T23:59:59.000Z

    The X-ray free-electron laser has opened a new era for photon science, improving the X-ray brightness by ten orders of magnitude over previously available sources. Similar to an optical laser, the spectral and temporal structure of the radiation pulses can be tailored to the specific needs of many experiments by accurately manipulating the lasing medium, that is, the electron beam. Here we report the generation of mJ-level two-colour hard X-ray pulses of few femtoseconds duration with an XFEL driven by twin electron bunches at the Linac Coherent Light Source. This performance represents an improvement of over an order of magnitudemore »in peak power over state-of-the-art two-colour XFELs. The unprecedented intensity and temporal coherence of this new two-colour X-ray free-electron laser enable an entirely new set of scientific applications, ranging from X-ray pump/X-ray probe experiments to the imaging of complex biological samples with multiple wavelength anomalous dispersion.« less

  11. Electron generation and transport in intense relativistic laser-plasma interactions relevant to fast ignition ICF

    E-Print Network [OSTI]

    Ma, Tammy Yee Wing

    2010-01-01T23:59:59.000Z

    Transport of Energy by Ultra-Intense Laser-Generated tronsof Energy by Ultra-Intense Laser-Generated Electrons inUltra-High In- tensity Lasers . . . . . . . . . . . . . . . . . . . . . . . .

  12. Radiation Reaction in High-Intense Fields

    E-Print Network [OSTI]

    Seto, Keita

    2015-01-01T23:59:59.000Z

    After the development of the radiating electron model by P. A. M. Dirac in 1938, many authors have tried to reformulate this model so-called radiation reaction. Recently, this effects has become important for ultra-intense laser-electron (plasma) interactions. In our recent research, we found a method for the stabilization of radiation reaction in quantum vacuum [PTEP 2014, 043A01 (2014), PTEP 2015, 023A01 (2015)]. In the other hand, the field modification by high-intense fields should be required under 10PW lasers, like ELI-NP facility. In this paper, I propose the combined method how to adopt the high-intense field correction with the stabilization by quantum vacuum as the extension from the model by Dirac.

  13. Intense steady state electron beam generator

    DOE Patents [OSTI]

    Hershcovitch, A.; Kovarik, V.J.; Prelec, K.

    1990-07-17T23:59:59.000Z

    An intense, steady state, low emittance electron beam generator is formed by operating a hollow cathode discharge plasma source at critical levels in combination with an extraction electrode and a target electrode that are operable to extract a beam of fast primary electrons from the plasma source through a negatively biased grid that is critically operated to repel bulk electrons toward the plasma source while allowing the fast primary electrons to move toward the target in the desired beam that can be successfully transported for relatively large distances, such as one or more meters away from the plasma source. 2 figs.

  14. Short rise time intense electron beam generator

    DOE Patents [OSTI]

    Olson, Craig L. (Albuquerque, NM)

    1987-01-01T23:59:59.000Z

    A generator for producing an intense relativistic electron beam having a subnanosecond current rise time includes a conventional generator of intense relativistic electrons feeding into a short electrically conductive drift tube including a cavity containing a working gas at a low enough pressure to prevent the input beam from significantly ionizing the working gas. Ionizing means such as a laser simultaneously ionize the entire volume of working gas in the cavity to generate an output beam having a rise time less than one nanosecond.

  15. Short rise time intense electron beam generator

    DOE Patents [OSTI]

    Olson, C.L.

    1984-03-16T23:59:59.000Z

    A generator for producing an intense relativisitc electron beam having a subnanosecond current rise time includes a conventional generator of intense relativistic electrons feeding into a short electrically conductive drift tube including a cavity containing a working gas at a low enough pressure to prevent the input beam from significantly ionizing the working gas. Ionizing means such as a laser simultaneously ionize the entire volume of working gas in the cavity to generate an output beam having a rise time less than one nanosecond.

  16. High-power, high-intensity laser propagation and interactions

    SciTech Connect (OSTI)

    Sprangle, Phillip [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Electrical and Computer Engineering and Physics, University of Maryland, College Park, Maryland 20740 (United States); Hafizi, Bahman [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2014-05-15T23:59:59.000Z

    This paper presents overviews of a number of processes and applications associated with high-power, high-intensity lasers, and their interactions. These processes and applications include: free electron lasers, backward Raman amplification, atmospheric propagation of laser pulses, laser driven acceleration, atmospheric lasing, and remote detection of radioactivity. The interrelated physical mechanisms in the various processes are discussed.

  17. Effect of the change in the load resistance on the high voltage pulse transformer of the intense electron-beam accelerators

    SciTech Connect (OSTI)

    Cheng Xinbing; Liu Jinliang; Qian Baoliang; Zhang Yu; Zhang Hongbo [College of Photoelectrical Science and Engineering, National University of Defense Technology, Hunan 410073 (China)

    2009-11-15T23:59:59.000Z

    A high voltage pulse transformer (HVPT) is usually used as a charging device for the pulse forming line (PFL) of intense electron-beam accelerators (IEBAs). Insulation of the HVPT is one of the important factors that restrict the development of the HVPT. Until now, considerable effort has been focused on minimizing high field regions to avoid insulation breakdown between windings. Characteristics of the HVPT have been widely discussed to achieve these goals, but the effects of the PFL and load resistance on HVPT are usually neglected. In this paper, a HVPT is used as a charging device for the PFL of an IEBA and the effect of the change in the load resistance on the HVPT of the IEBA is presented. When the load resistance does not match the wave impedance of the PFL, a high-frequency bipolar oscillating voltage will occur, and the amplitude of the oscillating voltage will increase with the decrease in the load resistance. The load resistance approximates to zero and the amplitude of the oscillating voltage is much higher. This makes it easier for surface flashover along the insulation materials to form and decrease the lifetime of the HVPT.

  18. Propagation In Matter Of Currents Of Relativistic Electrons Beyond The Alfven Limit, Produced In Ultra-High-Intensity Short-Pulse Laser-Matter Interactions

    SciTech Connect (OSTI)

    Batani, D.; Manclossi, M. [Dipartimento di Fisica 'G.Occhialini', Universita di Milano-Bicocca (Italy); INFM, Universita di Milano-Bicocca (Italy); Laboratoire d'Optique Appliquee, UMR ENSTA-CNRS-Ecole Polytechnique, Palaiseau (France); Baton, S.D.; Amiranoff, F.; Koenig, M.; Gremillet, L.; Popescu, H. [Laboratoire pour l'Utilisation des Lasers Intenses, UMR 7605 CNRS-CEA-X-Paris VI, Ecole Polytechnique, Palaiseau (France); Santos, J.J. [Laboratoire d'Optique Appliquee, UMR ENSTA-CNRS-Ecole Polytechnique, Palaiseau (France); Laboratoire pour l'Utilisation des Lasers Intenses, UMR 7605 CNRS-CEA-X-Paris VI, Ecole Polytechnique, Palaiseau (France); Martinolli, E. [Dipartimento di Fisica 'G.Occhialini', Universita di Milano-Bicocca (Italy); INFM, Universita di Milano-Bicocca (Italy); Laboratoire pour l'Utilisation des Lasers Intenses, UMR 7605 CNRS-CEA-X-Paris VI, Ecole Polytechnique, Palaiseau (France); Antonicci, A. [Dipartimento di Fisica 'G.Occhialini', Universita di Milano-Bicocca (Italy); INFM, Universita di Milano-Bicocca (Italy); Rousseaux, C.; Rabec Le Gloahec, M. [Commissariat a l'Energie Atomique, Bruyeres-le-Chatel (France); Hall, T. [University of Essex, Wivenhoe Park, Colchester, Essex, CO4 3SQ (United Kingdom); Malka, V. [Laboratoire d'Optique Appliquee, UMR ENSTA-CNRS-Ecole Polytechnique, Palaiseau (France); Cowan, T.E.; Stephens, R. [Inertial Fusion Technology Division, Fusion Group, General Atomics, San Diego, CA (United States); Key, M. [Lawrence Livermore National Laboratory, Livermore CA (United States); King, J.; Freeman, R. [Department of Applied Sciences, University of California Davis, CA 95616 (United States)

    2004-12-01T23:59:59.000Z

    This paper reports the results of several experiments performed at the LULI laboratory (Palaiseau, France) concerning the propagation of large relativistic currents in matter from ultra-high-intensity laser pulse interaction with target. We present our results according to the type of diagnostics used in the experiments: 1) K{alpha} emission and K{alpha} imaging, 2) study of target rear side emission in the visible region, 3) time resolved optical shadowgraphy.

  19. High intensity performance of the Brookhaven AGS

    SciTech Connect (OSTI)

    Brennan, J.M.; Roser, T.

    1996-07-01T23:59:59.000Z

    Experience and results from recent high intensity proton running periods of the Brookhaven AGS, during which a record intensity for a proton synchrotron of 6.3 x 10{sup 13} protons/pulse was reached, is presented. This high beam intensity allowed for the simultaneous operation of three high precision rare kaon decay experiments. The record beam intensities were achieved after the 1.5 GeV Booster was commissioned and a transition jump system, a powerful transverse damper, and an rf upgrade in the AGS were completed. Recently even higher intensity proton synchrotrons are studied for neutron spallation sources or proton driver for a muon collider. Implications of the experiences from the AGS to these proposals and also possible future upgrades for the AGS are discussed.

  20. Electron Production and Collective Field Generation in Intense Particle Beams

    SciTech Connect (OSTI)

    Molvik, A W; Vay, J; Cohen, R; Friedman, A; Lee, E; Verboncoeur, J; Covo, M K

    2006-02-09T23:59:59.000Z

    Electron cloud effects (ECEs) are increasingly recognized as important, but incompletely understood, dynamical phenomena, which can severely limit the performance of present electron colliders, the next generation of high-intensity rings, such as PEP-II upgrade, LHC, and the SNS, the SIS 100/200, or future high-intensity heavy ion accelerators such as envisioned in Heavy Ion Inertial Fusion (HIF). Deleterious effects include ion-electron instabilities, emittance growth, particle loss, increase in vacuum pressure, added heat load at the vacuum chamber walls, and interference with certain beam diagnostics. Extrapolation of present experience to significantly higher beam intensities is uncertain given the present level of understanding. With coordinated LDRD projects at LLNL and LBNL, we undertook a comprehensive R&D program including experiments, theory and simulations to better understand the phenomena, establish the essential parameters, and develop mitigating mechanisms. This LDRD project laid the essential groundwork for such a program. We developed insights into the essential processes, modeled the relevant physics, and implemented these models in computational production tools that can be used for self-consistent study of the effect on ion beams. We validated the models and tools through comparison with experimental data, including data from new diagnostics that we developed as part of this work and validated on the High-Current Experiment (HCX) at LBNL. We applied these models to High-Energy Physics (HEP) and other advanced accelerators. This project was highly successful, as evidenced by the two paragraphs above, and six paragraphs following that are taken from our 2003 proposal with minor editing that mostly consisted of changing the tense. Further benchmarks of outstanding performance are: we had 13 publications with 8 of them in refereed journals, our work was recognized by the accelerator and plasma physics communities by 8 invited papers and we have 5 additional invitations for invited papers at upcoming conferences, we attracted collaborators who had SBIR funding, we are collaborating with scientists at CERN and GSI Darmstadt on gas desorption physics for submission to Physical Review Letters, and another PRL on absolute measurements of electron cloud density and Phys. Rev. ST-AB on electron emission physics are also being readied for submission.

  1. Physics of intense, high energy radiation effects.

    SciTech Connect (OSTI)

    Hjalmarson, Harold Paul; Hartman, E. Frederick; Magyar, Rudolph J.; Crozier, Paul Stewart

    2011-02-01T23:59:59.000Z

    This document summarizes the work done in our three-year LDRD project titled 'Physics of Intense, High Energy Radiation Effects.' This LDRD is focused on electrical effects of ionizing radiation at high dose-rates. One major thrust throughout the project has been the radiation-induced conductivity (RIC) produced by the ionizing radiation. Another important consideration has been the electrical effect of dose-enhanced radiation. This transient effect can produce an electromagnetic pulse (EMP). The unifying theme of the project has been the dielectric function. This quantity contains much of the physics covered in this project. For example, the work on transient electrical effects in radiation-induced conductivity (RIC) has been a key focus for the work on the EMP effects. This physics in contained in the dielectric function, which can also be expressed as a conductivity. The transient defects created during a radiation event are also contained, in principle. The energy loss lead the hot electrons and holes is given by the stopping power of ionizing radiation. This information is given by the inverse dielectric function. Finally, the short time atomistic phenomena caused by ionizing radiation can also be considered to be contained within the dielectric function. During the LDRD, meetings about the work were held every week. These discussions involved theorists, experimentalists and engineers. These discussions branched out into the work done in other projects. For example, the work on EMP effects had influence on another project focused on such phenomena in gases. Furthermore, the physics of radiation detectors and radiation dosimeters was often discussed, and these discussions had impact on related projects. Some LDRD-related documents are now stored on a sharepoint site (https://sharepoint.sandia.gov/sites/LDRD-REMS/default.aspx). In the remainder of this document the work is described in catergories but there is much overlap between the atomistic calculations, the continuum calculations and the experiments.

  2. Generation of mega-electron-volt electron beams by an ultrafast intense laser pulse

    E-Print Network [OSTI]

    Umstadter, Donald

    Generation of mega-electron-volt electron beams by an ultrafast intense laser pulse Xiaofang Wang emission from the interaction of an ultrafast ( 29 fs), intense ( 1018 W/cm2 ) laser pulse with underdense of such an ultrafast laser pulse with matter and possible new approaches to MeV electron generation. In this paper we

  3. Delivering High IntensityDelivering High Intensity Proton Beam:Proton Beam

    E-Print Network [OSTI]

    McDonald, Kirk

    11 Delivering High IntensityDelivering High Intensity Proton Beam:Proton Beam: Lessons for the NextFACT08NuFACT08 ­­ 4 July4 July S. ChildressS. Childress ­­ Proton BeamsProton Beams 22 Presentation OutlinePresentation Outline Key Proton Beam ConsiderationsKey Proton Beam Considerations The First

  4. 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.

  5. Fundamental Physics Explored with High Intensity Laser

    E-Print Network [OSTI]

    T. Tajima; K. Homma

    2012-09-13T23:59:59.000Z

    Over the last Century the method of particle acceleration to high energies has become the prime approach to explore the fundamental nature of matter in laboratory. It appears that the latest search of the contemporary accelerator based on the colliders shows a sign of saturation (or at least a slow-down) in increasing its energy and other necessary parameters to extend this frontier. We suggest two pronged approach enabled by the recent progress in high intensity lasers.

  6. High-intensity positron microprobe at Jefferson Lab

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

    Golge, Serkan [North Carolina Central Univ., Durham, NC (United States); Vlahovic, Branislav [North Carolina Central Univ., Durham, NC (United States); Wojtsekhowski, Bogdan B. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2014-06-21T23:59:59.000Z

    We present a conceptual design for a novel continuous wave electron-linac based high-intensity slow-positron production source with a projected intensity on the order of 1010 e+/s. Reaching this intensity in our design relies on the transport of positrons (T+ below 600 keV) from the electron-positron pair production converter target to a low-radiation and low-temperature area for moderation in a high-efficiency cryogenic rare gas moderator, solid Ne. The performance of the integrated beamline has been verified through computational studies. The computational results include Monte Carlo calculations of the optimized electron/positron beam energies, converter target thickness, synchronized raster system, transport of the beam from the converter target to the moderator, extraction of the beam from the channel, and moderation efficiency calculations. For the extraction of positrons from the magnetic channel a magnetic field terminator plug prototype has been built and experimental data on the effectiveness of this prototype are presented. The dissipation of the heat away from the converter target and radiation protection measures are also discussed.

  7. High-intensity positron microprobe at Jefferson Lab

    SciTech Connect (OSTI)

    Golge, Serkan [North Carolina Central Univ., Durham, NC (United States); Vlahovic, Branislav [North Carolina Central Univ., Durham, NC (United States); Wojtsekhowski, Bogdan B. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2014-06-21T23:59:59.000Z

    We present a conceptual design for a novel continuous wave electron-linac based high-intensity slow-positron production source with a projected intensity on the order of 1010 e+/s. Reaching this intensity in our design relies on the transport of positrons (T+ below 600 keV) from the electron-positron pair production converter target to a low-radiation and low-temperature area for moderation in a high-efficiency cryogenic rare gas moderator, solid Ne. The performance of the integrated beamline has been verified through computational studies. The computational results include Monte Carlo calculations of the optimized electron/positron beam energies, converter target thickness, synchronized raster system, transport of the beam from the converter target to the moderator, extraction of the beam from the channel, and moderation efficiency calculations. For the extraction of positrons from the magnetic channel a magnetic field terminator plug prototype has been built and experimental data on the effectiveness of this prototype are presented. The dissipation of the heat away from the converter target and radiation protection measures are also discussed.

  8. High-intensity positron microprobe at Jefferson Lab

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

    Golge, Serkan; Vlahovic, Branislav; Wojtsekhowski, Bogdan B.

    2014-06-21T23:59:59.000Z

    We present a conceptual design for a novel continuous wave electron-linac based high-intensity slow-positron production source with a projected intensity on the order of 1010 e+/s. Reaching this intensity in our design relies on the transport of positrons (T+ below 600 keV) from the electron-positron pair production converter target to a low-radiation and low-temperature area for moderation in a high-efficiency cryogenic rare gas moderator, solid Ne. The performance of the integrated beamline has been verified through computational studies. The computational results include Monte Carlo calculations of the optimized electron/positron beam energies, converter target thickness, synchronized raster system, transport of themore »beam from the converter target to the moderator, extraction of the beam from the channel, and moderation efficiency calculations. For the extraction of positrons from the magnetic channel a magnetic field terminator plug prototype has been built and experimental data on the effectiveness of this prototype are presented. The dissipation of the heat away from the converter target and radiation protection measures are also discussed.« less

  9. Electron-Positron Plasma Drop Formed by Ultra-Intense Laser Pulses

    E-Print Network [OSTI]

    Inga Kuznetsova; Johann Rafelski

    2012-04-25T23:59:59.000Z

    We study the initial properties and positron annihilation within a small electron-positron plasma drop formed by intense laser pulse. Such QED cascade initiated plasma is, in general, far below the chemical (particle yield) equilibrium. We find that the available electrons and positrons equilibrate kinetically, yet despite relatively high particle density, the electron-positron annihilation is very slow, suggesting a rather long lifespan of the plasma drop.

  10. Title of Dissertation: CONTROL AND TRANSPORT OF INTENSE ELECTRON BEAMS

    E-Print Network [OSTI]

    Anlage, Steven

    ABSTRACT Title of Dissertation: CONTROL AND TRANSPORT OF INTENSE ELECTRON BEAMS Hui Li, Doctor of Philosophy, 2004 Dissertation Directed By: Professor, Patrick G. O'Shea Department of Electrical and Computer throughout the strong focusing lattice. We describe in this dissertation the main beam control techniques

  11. High intensity discharge device containing oxytrihalides

    DOE Patents [OSTI]

    Lapatovich, W.P.; Keeffe, W.M.; Liebermann, R.W.; Maya, J.

    1987-06-09T23:59:59.000Z

    A fill composition for a high intensity discharge device including mercury, niobium oxytrihalide, and a molecular stabilization agent is provided. The molar ratio of niobium oxytrihalide to the molecular stabilization agent in the fill is in the range of from about 5:1 to about 7.5:1. Niobium oxytrihalide is present in the fill in sufficient amount to produce, by dissociation in the discharge, atomic niobium, niobium oxide, NbO, and niobium dioxide, NbO[sub 2], with the molar ratio of niobium-containing vapor species to mercury in the fill being in the range of from about 0.01:1 to about 0.50:1; and mercury pressure of about 1 to about 50 atmospheres at lamp operating temperature. There is also provided a high intensity discharge device comprising a sealed light-transmissive arc tube; the arc tube including the above-described fill; and an energizing means for producing an electric discharge within the arc tube. 7 figs.

  12. Electrons in a relativistic-intensity laser field: generation of zeptosecond electromagnetic pulses and energy spectrum of the accelerated electrons

    SciTech Connect (OSTI)

    Andreev, A A; Galkin, A L; Kalashnikov, M P; Korobkin, V V; Romanovsky, Mikhail Yu; Shiryaev, O B [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2011-08-31T23:59:59.000Z

    We study the motion of an electron and emission of electromagnetic waves by an electron in the field of a relativistically intense laser pulse. The dynamics of the electron is described by the Newton equation with the Lorentz force in the right-hand side. It is shown that the electrons may be ejected from the interaction region with high energy. The energy spectrum of these electrons and the technique of using the spectrum to assess the maximal intensity in the focus are analysed. It is found that electromagnetic radiation of an electron moving in an intense laser field occurs within a small angle around the direction of the electron trajectory tangent. The tangent quickly changes its direction in space; therefore, electromagnetic radiation of the electron in the far-field zone in a certain direction in the vicinity of the tangent is a short pulse with a duration as short as zeptoseconds. The calculation of the temporary and spectral distribution of the radiation field is carried out. (superintense laser fields)

  13. High intensity neutrino oscillation facilities in Europe

    E-Print Network [OSTI]

    Edgecock, T R; Davenne, T; Densham, C; Fitton, M; Kelliher, D; Loveridge, P; Machida, S; Prior, C; Rogers, C; Rooney, M; Thomason, J; Wilcox, D; Wildner, E; Efthymiopoulos, I; Garoby, R; Gilardoni, S; Hansen, C; Benedetto, E; Jensen, E; Kosmicki, A; Martini, M; Osborne, J; Prior, G; Stora, T; Melo-Mendonca, T; Vlachoudis, V; Waaijer, C; Cupial, P; Chancé, A; Longhin, A; Payet, J; Zito, M; Baussan, E; Bobeth, C; Bouquerel, E; Dracos, M; Gaudiot, G; Lepers, B; Osswald, F; Poussot, P; Vassilopoulos, N; Wurtz, J; Zeter, V; Bielski, J; Kozien, M; Lacny, L; Skoczen, B; Szybinski, B; Ustrycka, A; Wroblewski, A; Marie-Jeanne, M; Balint, P; Fourel, C; Giraud, J; Jacob, J; Lamy, T; Latrasse, L; Sortais, P; Thuillier, T; Mitrofanov, S; Loiselet, M; Keutgen, Th; Delbar, Th; Debray, F; Trophine, C; Veys, S; Daversin, C; Zorin, V; Izotov, I; Skalyga, V; Burt, G; Dexter, A C; Kravchuk, V L; Marchi, T; Cinausero, M; Gramegna, F; De Angelis, G; Prete, G; Collazuol, G; Laveder, M; Mazzocco, M; Mezzetto, M; Signorini, C; Vardaci, E; Di Nitto, A; Brondi, A; La Rana, G; Migliozzi, P; Moro, R; Palladino, V; Gelli, N; Berkovits, D; Hass, M; Hirsh, T Y; Schaumann, M; Stahl, A; Wehner, J; Bross, A; Kopp, J; Neuffer, D; Wands, R; Bayes, R; Laing, A; Soler, P; Agarwalla, S K; Villanueva, A Cervera; Donini, A; Ghosh, T; Cadenas, J J Gómez; Hernández, P; Martín-Albo, J; Mena, O; Burguet-Castell, J; Agostino, L; Buizza-Avanzini, M; Marafini, M; Patzak, T; Tonazzo, A; Duchesneau, D; Mosca, L; Bogomilov, M; Karadzhov, Y; Matev, R; Tsenov, R; Akhmedov, E; Blennow, M; Lindner, M; Schwetz, T; Martinez, E Fernández; Maltoni, M; Menéndez, J; Giunti, C; García, M C González; Salvado, J; Coloma, P; Huber, P; Li, T; López-Pavón, J; Orme, C; Pascoli, S; Meloni, D; Tang, J; Winter, W; Ohlsson, T; Zhang, H; Scotto-Lavina, L; Terranova, F; Bonesini, M; Tortora, L; Alekou, A; Aslaninejad, M; Bontoiu, C; Kurup, A; Jenner, L J; Long, K; Pasternak, J; Pozimski, J; Back, J J; Harrison, P; Beard, K; Bogacz, A; Berg, J S; Stratakis, D; Witte, H; Snopok, P; Bliss, N; Cordwell, M; Moss, A; Pattalwar, S; Apollonio, M

    2013-01-01T23:59:59.000Z

    The EUROnu project has studied three possible options for future, high intensity neutrino oscillation facilities in Europe. The first is a Super Beam, in which the neutrinos come from the decay of pions created by bombarding targets with a 4 MW proton beam from the CERN High Power Superconducting Proton Linac. The far detector for this facility is the 500 kt MEMPHYS water Cherenkov, located in the Fr\\'ejus tunnel. The second facility is the Neutrino Factory, in which the neutrinos come from the decay of {\\mu}+ and {\\mu}- beams in a storage ring. The far detector in this case is a 100 kt Magnetised Iron Neutrino Detector at a baseline of 2000 km. The third option is a Beta Beam, in which the neutrinos come from the decay of beta emitting isotopes, in particular 6He and 18Ne, also stored in a ring. The far detector is also the MEMPHYS detector in the Fr\\'ejus tunnel. EUROnu has undertaken conceptual designs of these facilities and studied the performance of the detectors. Based on this, it has determined the ph...

  14. Nonlinear relativistic single-electron Thomson scattering power spectrum for incoming laser of arbitrary intensity

    SciTech Connect (OSTI)

    Alvarez-Estrada, R. F. [Departamento de Fisica Teorica I, Facultad de Ciencias Fisicas, Universidad Complutense, 28040 Madrid (Spain); Pastor, I.; Guasp, J.; Castejon, F. [Asociacion Euratom/Ciemat para Fusion, Avenida Complutense 22, 28040 Madrid (Spain)

    2012-06-15T23:59:59.000Z

    The classical nonlinear incoherent Thomson scattering power spectrum from a single relativistic electron with incoming laser radiation of any intensity, investigated numerically by the present authors in a previous publication, displayed both an approximate quadratic behavior in frequency and a redshift of the power spectrum for high intensity incoming radiation. The present work is devoted to justify, in a more general setup, those numerical findings. Those justifications are reinforced by extending suitably analytical approaches, as developed by other authors. Moreover, our analytical treatment exhibits differences between the Doppler-like frequencies for linear and circular polarization of the incoming radiation. Those differences depend nonlinearly on the laser intensity and on the electron initial velocity and do not appear to have been displayed by previous authors. Those Doppler-like frequencies and their differences are validated by new Monte Carlo computations beyond our previuos ones and reported here.

  15. Performances of BNL high-intensity synchrotrons

    SciTech Connect (OSTI)

    Weng, W.T.

    1998-03-01T23:59:59.000Z

    The AGS proton synchrotron was completed in 1960 with initial intensity in the 10 to the 10th power proton per pulse (ppp) range. Over the years, through many upgrades and improvements, the AGS now reached an intensity record of 6.3 {times} 10{sup 13} ppp, the highest world intensity record for a proton synchrotron on a single pulse basis. At the same time, the Booster reached 2.2 {times} 10{sup 13} ppp surpassing the design goal of 1.5 {times} 10{sup 13} ppp due to the introduction of second harmonic cavity during injection. The intensity limitation caused by space charge tune spread and its relationship to injection energy at 50 MeV, 200 MeV, and 1,500 MeV will be presented as well as many critical accelerator manipulations. BNL currently participates in the design of an accumulator ring for the SNS project at Oak Ridge. The status on the issues of halo formation, beam losses and collimation are also presented.

  16. The investigation of high intensity laser driven micro neutron sources

    E-Print Network [OSTI]

    Ghoniem, Nasr M.

    , access to high temperature states of mat- ter capable of thermonuclear fusion and/or the effi- cientThe investigation of high intensity laser driven micro neutron sources for fusion materials. The application of fast pulse, high intensity lasers to drive low cost DT point neutron sources for fusion

  17. Fundamental physics on natures of the macroscopic vacuum under high intense electromagnetic fields with accelerators

    E-Print Network [OSTI]

    Kensuke Homma

    2009-11-30T23:59:59.000Z

    High intense electromagnetic fields can be unique probes to study natures of macroscopic vacua by themselves. Combining accelerators with the intense field can provide more fruitful probes which can neither be achieved by only intense fields nor only high energy accelerators. We will overview the natures of vacua which can be accessible via intense laser-laser and intense laser-electron interactions. In the case of the laser-laser interaction, we propose how to observe nonlinear QED effects and effects of new fields like light scalar and pseudo scalar fields which may contribute to a macroscopic nature of our universe such as dark energy. In the case of the laser-electron interaction, in addition to nonlinear QED effects, we can further discuss the nature of accelerating field in the vacuum where we can access physics related with event horizons such as Hawking-Unruh radiations. We will introduce a recent experimental trial to search for this kind of odd radiations.

  18. Isochoric heating of reduced mass targets by ultra-intense laser produced relativistic electrons

    SciTech Connect (OSTI)

    Neumayer, P; Lee, H J; Offerman, D; Shipton, E; Kemp, A; Kritcher, A L; Doppner, T; Back, C A; Glenzer, S H

    2009-02-04T23:59:59.000Z

    We present measurements of the chlorine K-alpha emission from reduced mass targets, irradiated with ultra-high intensity laser pulses. Chlorinated plastic targets with diameters down to 50 micrometers and mass of a few 10{sup -8} g were irradiated with up to 7 J of laser energy focused to intensities of several 10{sup 19} W/cm{sup 2}. The conversion of laser energy to K-alpha radiation is measured, as well as high resolution spectra that allow observation of line shifts, indicating isochoric heating of the target up to 18 eV. A zero-dimensional 2-temperature equilibration model, combined with electron impact K-shell ionization and post processed spectra from collisional radiative calculations reproduces the observed K-alpha yields and line shifts, and shows the importance of target expansion due to the hot electron pressure.

  19. Intense pulsed light sintering of copper nanoink for printed electronics

    E-Print Network [OSTI]

    Kim, Hak-Sung; Dhage, Sanjay R.; Shim, Dong-Eun; Hahn, H. Thomas

    2009-01-01T23:59:59.000Z

    copper nanoink for printed electronics Hak-Sung Kim · Sanjay1 Introduction Printed electronics techniques such as inkjetcomponents of printed electronics are conducting lines and ?

  20. Kinetic-energy-angle differential distribution of photofragments in multiphoton above-threshold dissociation of D{sub 2}{sup +} by linearly polarized 400-nm intense laser fields: Effects of highly excited electronic states

    SciTech Connect (OSTI)

    Khan, Basir Ahamed; Saha, Samir; Bhattacharyya, S. S. [Atomic and Molecular Physics Section, Department of Materials Science, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India)

    2006-02-15T23:59:59.000Z

    We have performed a detailed calculation of the double-differential angular-kinetic-energy distribution of photofragments in above threshold dissociation (ATD) of D{sub 2}{sup +} from initial vibrational-rotational levels v{sub i}=4,5 and J{sub i}=0,1 in an intense linearly polarized laser field of wavelength 400 nm and intensity 3x10{sup 13} W/cm{sup 2}. The calculation used a time-independent close-coupling (CC) formalism with eight (ten) electronic states included in the basis-set expansion of the molecular wave function. The molecular electronic states included, apart from the two lowest 1s{sigma}{sub g} and 2p{sigma}{sub u} states, were 2p{pi}{sub u}{sup {+-}}, 2s{sigma}{sub g}, 3p{sigma}{sub u}, 3d{sigma}{sub g}, 3d{pi}{sub g}{sup {+-}}, and 4f{sigma}{sub u}. All the higher electronic states dissociate to the atomic state D(2l). A sufficient number of photon absorption channels, n=0-7, and molecular rotational quantum numbers J=0-11 were taken into account to ensure the convergence of the multiphoton ATD probability. Altogether 198 coupled channels had to be considered in the calculation. The calculations reveal signatures of significant ejection of the photodissociation fragments away from the laser polarization direction due to the inclusion of the higher excited electronic states. The ratio of the photofragments perpendicular to and along the polarization axis shows good quantitative agreement with the experimental result. The angular distributions show considerable structures depending on the relative kinetic energies of the photofragments, and the fragments with different kinetic energies show peaks at different dissociation angles.

  1. An improved high intensity recycling helium-3 beam source

    SciTech Connect (OSTI)

    Hedgeland, H.; Kole, P. R.; Allison, W.; Ellis, J.; Jardine, A. P. [Cavendish Laboratory, JJ Thomson Ave., Cambridge CB3 0HE (United Kingdom)

    2009-07-15T23:59:59.000Z

    We describe an improved high intensity, recycling, supersonic atomic beam source. Changes address several issues previously limiting performance and reliability of the apparatus, including the use of newly available vacuum pumps and modifications to the recycling system. We achieve a source intensity of 2.5x10{sup 19} atoms/s/sr, almost twice that previously achievable during recycling. Current limits on intensity are discussed.

  2. Intense terahertz pulses from SLAC electron beams using coherent transition radiation

    SciTech Connect (OSTI)

    Wu Ziran; Fisher, Alan S.; Hogan, Mark; Loos, Henrik [Accelerator Directorate, SLAC National Accelerator Laboratory, Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Goodfellow, John [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Fuchs, Matthias [Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Daranciang, Dan [Department of Chemistry, Stanford University, Stanford, California 94305 (United States); Lindenberg, Aaron [Department of Materials Science and Engineering, Stanford University, Stanford, California 94305 (United States); Stanford Institute for Materials and Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

    2013-02-15T23:59:59.000Z

    SLAC has two electron accelerators, the Linac Coherent Light Source (LCLS) and the Facility for Advanced Accelerator Experimental Tests (FACET), providing high-charge, high-peak-current, femtosecond electron bunches. These characteristics are ideal for generating intense broadband terahertz (THz) pulses via coherent transition radiation. For LCLS and FACET respectively, the THz pulse duration is typically 20 and 80 fs RMS and can be tuned via the electron bunch duration; emission spectra span 3-30 THz and 0.5 THz-5 THz; and the energy in a quasi-half-cycle THz pulse is 0.2 and 0.6 mJ. The peak electric field at a THz focus has reached 4.4 GV/m (0.44 V/A) at LCLS. This paper presents measurements of the terahertz pulses and preliminary observations of nonlinear materials response.

  3. High-intensity beam collimation and targetry

    SciTech Connect (OSTI)

    Mokhov, N.V.; /Fermilab

    2006-11-01T23:59:59.000Z

    Principles, design criteria and realization of reliable collimation systems for the high-power accelerators and hadron colliders are described. Functionality of collimators as the key elements of the machine protection system are discussed along with the substantial progress on the crystal collimation front. The key issues are considered in design of high-power target systems and achieving their best performance. Simulation code requirements are presented.

  4. Study of high frequency & low frequency electronic ballasts for HID lamps

    E-Print Network [OSTI]

    Peng, Hua

    1997-01-01T23:59:59.000Z

    High-intensity discharge (HID) lamp electronic ballasting is receiving increasing attention in the recent years as low wattage HID lighting systems are finding indoor applications. Advantages of high frequency electronic ballast for HID lamps...

  5. Dynamics of an electron in a relativistically intense laser field including radiaion reaction

    SciTech Connect (OSTI)

    Galkin, A. L., E-mail: galkin@kapella.gpi.ru [Prokhorov General Physics Institute of the Russian Academy of Science (Russian Federation)

    2012-08-15T23:59:59.000Z

    The dynamics of an electron in a relativistically intense laser pulse field is described with the radiation reaction being taken into account. The study is based on solving the Newton equation with the Lorentz and the radiation reaction forces. Validation is provided for an iteration technique which makes it possible to remove the discrepancies found in the theoretical models of radiation reaction. It is demonstrated that an electron having a high initial velocity and colliding head-on with a laser pulse sheds a considerable part of its kinetic energy due to the radiation reaction. A broadening of the electromagnetic pulse emitted by the electron occurs as a result of the same effect. The findings obtained can be used to experimentally verify the effect of radiation reaction.

  6. Electron generation and transport in intense relativistic laser-plasma interactions relevant to fast ignition ICF

    E-Print Network [OSTI]

    Ma, Tammy Yee Wing

    2010-01-01T23:59:59.000Z

    Ultra-Short Pulse, Ultra-High In- tensity Lasers . . . . . . . . . . . . . . . . . . . . . . . .ignition), an ultra-intense short pulse laser is brought inof the ultra-high intensity, short-pulse laser has opened up

  7. Title of dissertation: NOVEL APPLICATIONS OF HIGH INTENSITY FEMTOSECOND LASERS

    E-Print Network [OSTI]

    Anlage, Steven

    -cycle seed pulse of terahertz radiation: a short, intense optical pulse (or sequence of pulses) aligns for amplification of few-cycle, high energy pulses of terahertz radiation. We report the development of corrugated the limitations of diffraction, phase matching, and material damage thresholds and promise to allow high

  8. On the high intensity aspects of AGS Booster proton operation

    SciTech Connect (OSTI)

    Reece, R.K.; Ahrens, L.A.; Bleser, E.J.; Brennan, J.M.; Gardner, C.; Glenn, J.W.; Roser, T.; Shoji, Y.; van Asselt, W.; Weng, W.T.

    1993-01-01T23:59:59.000Z

    Observations of high intensity effects on the proton performance of the AGS Booster are presented, including present operational limits and correction methods. The transverse emittances, optimum tune working points, damping of coherent transverse oscillations and correction of stopband resonances through third-order are discussed in addition to the observed tune spread due to space charge forces. The initial longitudinal phase space distribution, capture and acceleration parameters and measurements are also given. Operational tools and strategies relevant to the high intensity setup are mentioned.

  9. On the high intensity aspects of AGS Booster proton operation

    SciTech Connect (OSTI)

    Reece, R.K.; Ahrens, L.A.; Bleser, E.J.; Brennan, J.M.; Gardner, C.; Glenn, J.W.; Roser, T.; Shoji, Y.; van Asselt, W.; Weng, W.T.

    1993-06-01T23:59:59.000Z

    Observations of high intensity effects on the proton performance of the AGS Booster are presented, including present operational limits and correction methods. The transverse emittances, optimum tune working points, damping of coherent transverse oscillations and correction of stopband resonances through third-order are discussed in addition to the observed tune spread due to space charge forces. The initial longitudinal phase space distribution, capture and acceleration parameters and measurements are also given. Operational tools and strategies relevant to the high intensity setup are mentioned.

  10. Title of dissertation: Precision Control of Intense Electron Beams in a Low-Energy Ring

    E-Print Network [OSTI]

    Anlage, Steven

    ABSTRACT Title of dissertation: Precision Control of Intense Electron Beams in a Low-Energy Ring. Research reported in this dissertation was done on the University of Maryland Electron Ring (UMER ELECTRON BEAMS IN A LOW-ENERGY RING by Chao Wu Dissertation submitted to the Faculty of the Graduate School

  11. Injection of harmonics generated in gas in a free-electron laser providing intense and

    E-Print Network [OSTI]

    Loss, Daniel

    LETTERS Injection of harmonics generated in gas in a free-electron laser providing intense lasers promise to extend this down to femtosecond timescales. The process by which free-electron lasers of the free-electron laser saturation length, and the generation of nonlinear harmonics13 at 54 nm and 32 nm

  12. Longitudinal and transverse cooling of relativistic electron beams in intense laser pulses

    E-Print Network [OSTI]

    Yoffe, Samuel R; Noble, Adam; Jaroszynski, Dino A

    2015-01-01T23:59:59.000Z

    With the emergence in the next few years of a new breed of high power laser facilities, it is becoming increasingly important to understand how interacting with intense laser pulses affects the bulk properties of a relativistic electron beam. A detailed analysis of the radiative cooling of electrons indicates that, classically, equal contributions to the phase space contraction occur in the transverse and longitudinal directions. In the weakly quantum regime, in addition to an overall reduction in beam cooling, this symmetry is broken, leading to significantly less cooling in the longitudinal than the transverse directions. By introducing an efficient new technique for studying the evolution of a particle distribution, we demonstrate the quantum reduction in beam cooling, and find that it depends on the distribution of energy in the laser pulse, rather than just the total energy as in the classical case.

  13. MATERIAL STUDIES FOR PULSED HIGH-INTENSITY PROTON BEAM TARGETS

    E-Print Network [OSTI]

    McDonald, Kirk

    /mechanical property changes experiment for baseline materials Carbon-Carbon composite This low-Z composite gives;PHASE I: Graphite & Carbon-Carbon Targets #12;E951 Results: ATJ Graphite vs. Carbon-Carbon CompositePLAN MATERIAL STUDIES FOR PULSED HIGH-INTENSITY PROTON BEAM TARGETS Nicholas Simos, Harold Kirk

  14. Drift tube suspension for high intensity linear accelerators

    DOE Patents [OSTI]

    Liska, D.J.; Schamaun, R.G.; Clark, D.C.; Potter, R.C.; Frank, J.A.

    1980-03-11T23:59:59.000Z

    The disclosure relates to a drift tube suspension for high intensity linear accelerators. The system comprises a series of box-sections girders independently adjustably mounted on a linear accelerator. A plurality of drift tube holding stems are individually adjustably mounted on each girder.

  15. Conceptual design of a superconducting high-intensity proton linac

    SciTech Connect (OSTI)

    Dominic Chan, K.C.

    1996-09-01T23:59:59.000Z

    A SCRF (superconducting RF linac) has been developed for a high-intensity proton linac which will be used as the driver for neutron sources. This design is conservative, using current SCRF technologies. As well as lowering operating cost, the design offers performance advantages in availability, beam loss, and upgradability, which are important for the application as a neutron source.

  16. FREE ELECTRON LASERS AND HIGH-ENERGY ELECTRON COOLING* Vladimir N. Litvinenko, BNL, Upton, Long Island, NY, USA#

    E-Print Network [OSTI]

    two orders-of-magnitude. Two techniques offering the potential to cool high- energy hadron beamsFREE ELECTRON LASERS AND HIGH-ENERGY ELECTRON COOLING* Vladimir N. Litvinenko, BNL, Upton, Long Island, NY, USA# Yaroslav S. Derbenev, TJNAF, Newport News, VA, USA) Abstract Cooling intense high

  17. Temporary Acceleration of Electrons While Inside an Intense Electromagnetic Pulse Kirk T. McDonald

    E-Print Network [OSTI]

    McDonald, Kirk

    Temporary Acceleration of Electrons While Inside an Intense Electromagnetic Pulse Kirk T. Mc. In- tense electromagnetic pulses of astrophysical origin can lead to very energetic photons via of the electromagnetic pulse [3]. The resulting temporary energy transfer to the longitudinal motion of the electron can

  18. Note on the set of Bragg peaks with high intensity

    E-Print Network [OSTI]

    Daniel Lenz; Nicolae Strungaru

    2014-12-23T23:59:59.000Z

    We consider diffraction of Delone sets in Euclidean space. We show that the set of Bragg peaks with high intensity is always Meyer (if it is relatively dense). We use this to provide a new characterization for Meyer sets in terms of positive and positive definite measures. Our results are based on a careful study of positive definite measures, which may be of interest in its own right.

  19. High-energy electron beam technology

    SciTech Connect (OSTI)

    Danko, J.C.; Lundin, C.D. (Univ. of Tennessee, Knoxville, TN (United States)); Nolting, E.E. (Naval Surface Warfare Center, White Oak, MD (United States))

    1994-09-01T23:59:59.000Z

    A high-energy electron beam (HEEB) technology was developed under the US Department of Defense (DOD) charged-particle-beam (CPB) directed-energy program. The program's objective was advanced military weapon systems. For the past two decades, charged-particle-beam research focused on producing intense beams and the vehicles to deliver large amounts of electrical energy. The charged-particle beams of interest for weapon systems had particle energies up to 100 MeV, beam currents of tens of kiloamperes, and propagation distances in excess of 100 m. However, such high energy levels are not required for industrial uses of the technology. It is anticipated that these less-aggressive beams will provide an electrical heat source suitable for a variety of materials processing applications, including surface treatment, joining, shock hardening, phase-transformation hardening, peening, shock-wave compaction, and melting. Much more R and D is needed to transfer to industry the high-energy electron beam technology developed in the CPB program. For example, its power as a materials processing tool must be convincingly demonstrated. Also required are compact, reliable accelerators that are relatively simple to use and reasonably priced.

  20. High-intensity positron microprobe at the Thomas Jefferson National Accelerator Facility

    SciTech Connect (OSTI)

    Golge, S., E-mail: serkan.golge@nasa.gov; Vlahovic, B. [North Carolina Central University, Durham, North Carolina 27707 (United States); Wojtsekhowski, B. [Jefferson Laboratory, 12000 Jefferson Ave., Newport News, Virginia 23606 (United States)

    2014-06-21T23:59:59.000Z

    We present a conceptual design for a novel continuous wave electron-linac based high-intensity high-brightness slow-positron production source with a projected intensity on the order of 10{sup 10?}e{sup +}/s. Reaching this intensity in our design relies on the transport of positrons (T{sub +} below 600?keV) from the electron-positron pair production converter target to a low-radiation and low-temperature area for moderation in a high-efficiency cryogenic rare gas moderator, solid Ne. This design progressed through Monte Carlo optimizations of: electron/positron beam energies and converter target thickness, transport of the e{sup +} beam from the converter to the moderator, extraction of the e{sup +} beam from the magnetic channel, a synchronized raster system, and moderator efficiency calculations. For the extraction of e{sup +} from the magnetic channel, a magnetic field terminator plug prototype has been built and experimental results on the effectiveness of the prototype are presented. The dissipation of the heat away from the converter target and radiation protection measures are also discussed.

  1. Measurements of electron density and temperature in the H-1 heliac plasma by helium line intensity ratios

    SciTech Connect (OSTI)

    Ma Shuiliang; Howard, John; Blackwell, Boyd D.; Thapar, Nandika [Plasma Research Laboratory, Australian National University, Canberra ACT 0200 (Australia)

    2012-03-15T23:59:59.000Z

    Electron density and temperature distributions in the H-1 heliac plasma are measured using the helium line intensity ratio technique based on a collisional-radiative model. An inversion approach with minimum Fisher regularization is developed to reconstruct the ratios of the local emission radiances from detected line-integrated intensities. The electron density and temperature inferred from the He I 667.8/728.1 and He I 728.1/706.5 nm line ratios are in good agreement with those from other diagnostic techniques in the inner region of the plasma. The electron density and temperature values appear to be a little high in the outer region of the plasma. Some possible causes of the discrepancy in the outer region are discussed.

  2. FNAL Proton Source High Intensity Operations and Beam Loss Control

    E-Print Network [OSTI]

    Garcia, F G

    2014-01-01T23:59:59.000Z

    The 40-year-old Fermilab Proton Source machines, constituted by the Pre-Injector, Linac and the synchrotron Booster, have been the workhorse of the Fermi National Accelerator Laboratory (Fermilab). During this time, the High Energy Physics Program has demanded an increase in proton throughput, especially during the past decade with the beginning of the neutrino program at Fermilab. In order to achieve a successful program, major upgrades and changes were made in Booster. Once again, the Proton Source has been charged to double their beam throughput, while maintain the present residual activation levels, to meet the laboratory Intensity Frontier program goals until new machines are built and operational to replace the Proton Source machines. This paper discusses the present performance of Booster and the plans involved in reaching even higher intensities.

  3. Intensity-dependent enhancements in high-order above-threshold ionization

    SciTech Connect (OSTI)

    Milosevic, D. B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany); Hasovic, E.; Gazibegovic-Busuladzic, A. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo, Bosnia and Herzegovina (Bosnia and Herzegowina); Busuladzic, M. [Medical Faculty, University of Sarajevo, Cekalusa 90, 71000 Sarajevo (Bosnia and Herzegowina); Becker, W. [Max-Born-Institut, Max-Born-Strasse 2a, 12489 Berlin (Germany)

    2007-11-15T23:59:59.000Z

    The very pronounced intensity-dependent enhancements of groups of peaks of high-order above-threshold-ionization spectra of rare-gas atoms are investigated using an improved version of the strong-field approximation, which realistically models the respective atom. Two types of enhancements are found and explained in terms of constructive interference of the contributions of a large number of long quantum orbits. The first type is observed for intensities slightly below channel closings. Its intensity dependence is comparatively smooth and it is generated by comparatively few (of the order of 20) orbits. The second type occurs precisely at channel closings and exhibits an extremely sharp intensity dependence. It requires constructive interference of a very large number of long orbits (several hundreds) and generates cusps in the electron spectrum at integer multiples of the laser-photon energy. An interpretation of these enhancements as a threshold phenomenon is also given. An interplay of different types of the threshold anomalies is observed. The position of both types of enhancements, in the photoelectron-energy--laser-intensity plane, shifts to the next channel closing intensity with the change of the ground-state parity. The enhancements gradually disappear with decreasing laser pulse duration. This confirms the interpretation of enhancements as a consequence of the interference of long strong-laser-field-induced quantum orbits.

  4. Narrowband inverse Compton scattering x-ray sources at high laser intensities

    E-Print Network [OSTI]

    Seipt, D; Surzhykov, A; Fritzsche, S

    2014-01-01T23:59:59.000Z

    Narrowband x- and gamma-ray sources based on the inverse Compton scattering of laser pulses suffer from a limitation of the allowed laser intensity due to the onset of nonlinear effects that increase their bandwidth. It has been suggested that laser pulses with a suitable frequency modulation could compensate this ponderomotive broadening and reduce the bandwidth of the spectral lines, which would allow to operate narrowband Compton sources in the high-intensity regime. In this paper we, therefore, present the theory of nonlinear Compton scattering in a frequency modulated intense laser pulse. We systematically derive the optimal frequency modulation of the laser pulse from the scattering matrix element of nonlinear Compton scattering, taking into account the electron spin and recoil. We show that, for some particular scattering angle, an optimized frequency modulation completely cancels the ponderomotive broadening for all harmonics of the backscattered light. We also explore how sensitive this compensation ...

  5. A Review of Loss Mechanisms and Key Design Choices for High Intensity Hadron Rings

    SciTech Connect (OSTI)

    Warsop, C.M. [Rutherford Appleton Laboratory, Oxfordshire (United Kingdom)

    2005-06-08T23:59:59.000Z

    The peak performance reached in a high intensity ring is closely related to the ability to minimise and control beam loss. The need to increase intensity has to be balanced against possible increased induction of radioactivity and the risk of interrupted operations. Losses are dependent on many factors and influence most aspects of machine design. In principle, only one aspect of low loss design needs to be sub-optimal to impose severe intensity limitations. Here, an outline is given of the key factors that need to be considered, focussing primarily on low to medium energy proton machines. Topics include space charge, instabilities, electron effects, injection and main lattice choices. Finally, we note that major progress has been made in refining low loss designs but there is still important work to be done in predicting loss levels and distributions in detail.

  6. Optical Fiber High Temperature Sensor Instrumentation for Energy Intensive Industries

    SciTech Connect (OSTI)

    Cooper, Kristie L.; Wang, Anbo; Pickrell, Gary R.

    2006-11-14T23:59:59.000Z

    This report summarizes technical progress during the program “Optical Fiber High Temperature Sensor Instrumentation for Energy Intensive Industries”, performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The objective of this program was to use technology recently invented at Virginia Tech to develop and demonstrate the application of self-calibrating optical fiber temperature and pressure sensors to several key energy-intensive industries where conventional, commercially available sensors exhibit greatly abbreviated lifetimes due primarily to environmental degradation. A number of significant technologies were developed under this program, including • a laser bonded silica high temperature fiber sensor with a high temperature capability up to 700°C and a frequency response up to 150 kHz, • the world’s smallest fiber Fabry-Perot high temperature pressure sensor (125 x 20 ?m) with 700°C capability, • UV-induced intrinsic Fabry-Perot interferometric sensors for distributed measurement, • a single crystal sapphire fiber-based sensor with a temperature capability up to 1600°C. These technologies have been well demonstrated and laboratory tested. Our work plan included conducting major field tests of these technologies at EPRI, Corning, Pratt & Whitney, and Global Energy; field validation of the technology is critical to ensuring its usefulness to U.S. industries. Unfortunately, due to budget cuts, DOE was unable to follow through with its funding commitment to support Energy Efficiency Science Initiative projects and this final phase was eliminated.

  7. Electrodeless HID lamp study. Final report. [High intensity discharge

    SciTech Connect (OSTI)

    Anderson, J.M.; Johnson, P.D.; Jones, C.E.; Rautenberg, T.H.

    1985-01-01T23:59:59.000Z

    High intensity discharge lamps excited by solenoidal electric fields (SEF/HID) were examined for their ability to give high brightness, high efficacy and good color. Frequency of operation was 13.56 MHz (ISM Band) and power to the lamp plasma ranged from about 400 to 1000 W. Radio frequency transformers with air cores and with air core complemented by ferrite material in the magnetic path were used to provide the voltage for excitation. Electrical properties of the matching network and the lamp plasma were measured or calculated and total light from the lamp was measured by an integrating sphere. Efficacies calculated from measurement were found to agree well with the positive column efficacies of conventional HID lamps containing only mercury, and with additives of sodium, thallium, and scandium iodide. Recommendations for future work are given.

  8. Beam instrumentation for future high intense hadron accelerators at Fermilab

    SciTech Connect (OSTI)

    Wendt, M.; Hu, M.; Tassotto, G.; Thurman-Keup, R.; Scarpine, V.; Shin, S.; Zagel, J.; /Fermilab

    2008-08-01T23:59:59.000Z

    High intensity hadron beams of up to 2 MW beam power are a key element of new proposed experimental facilities at Fermilab. Project X, which includes a SCRF 8 GeV H{sup -} linac, will be the centerpiece of future HEP activities in the neutrino sector. After a short overview of this, and other proposed projects, we present the current status of the beam instrumentation activities at Fermilab with a few examples. With upgrades and improvements they can meet the requirements of the new beam facilities, however design and development of new instruments is needed, as shown by the prototype and conceptual examples in the last section.

  9. Summary of sessions B and F: High intensity linacs and frontend & proton drivers

    SciTech Connect (OSTI)

    Ferdinand, R.; /Saclay; Chou, W.; /Fermilab; Galambos, J.; /Oak Ridge

    2005-01-01T23:59:59.000Z

    This paper summarizes the sessions B&F of the 33rd ICFA Advanced Beam Dynamics Workshop on High Intensity & High Brightness Hadron Beams held in Bensheim, Germany. It covers high intensity linacs, front ends and proton driver topics.

  10. Ultra-High Intensity Magnetic Field Generation in Dense Plasma

    SciTech Connect (OSTI)

    Fisch, Nathaniel J

    2014-01-08T23:59:59.000Z

    I. Grant Objective The main objective of this grant proposal was to explore the efficient generation of intense currents. Whereasthefficient generation of electric current in low-­?energy-­? density plasma has occupied the attention of the magnetic fusion community for several decades, scant attention has been paid to carrying over to high-­?energy-­? density plasma the ideas for steady-­?state current drive developed for low-­?energy-­? density plasma, or, for that matter, to inventing new methodologies for generating electric current in high-­?energy-­?density plasma. What we proposed to do was to identify new mechanisms to accomplish current generation, and to assess the operation, physics, and engineering basis of new forms of current drive in regimes appropriate for new fusion concepts.

  11. Determination of electron temperature from spectral line intensity decay for radiation dominated plasmas

    SciTech Connect (OSTI)

    Michael, C.A.; Howard, J. [PRL, RSPhysSE, Australian National University, Canberra A.C.T. 0200 (Australia)

    2004-10-01T23:59:59.000Z

    We describe a technique to absolutely estimate the electron temperature in radiation dominated plasmas from the temporal decay during the plasma afterglow of the intensity of a single spectral line. The model and underlying assumptions are described. We apply the model to data in both rf heated argon discharges and electron cyclotron heated He/H discharges in the H-1 heliac. The results agree well with probe measurements.

  12. Proceedings of the third ICFA mini-workshop on high intensity, high brightness hadron accelerators

    SciTech Connect (OSTI)

    Roser, T.

    1997-11-01T23:59:59.000Z

    The third mini-workshop on high intensity, high brightness hadron accelerators was held at Brookhaven National Laboratory on May 7-9, 1997 and had about 30 participants. The workshop focussed on rf and longitudinal dynamics issues relevant to intense and/or bright hadron synchrotrons. A plenary session was followed by four sessions on particular topics. This document contains copies of the viewgraphs used as well as summaries written by the session chairs.

  13. Temporary Acceleration of Electrons While Inside an Intense Electromagnetic Pulse Kirk T. McDonald

    E-Print Network [OSTI]

    McDonald, Kirk

    Temporary Acceleration of Electrons While Inside an Intense Electromagnetic Pulse Kirk T. Mc. In­ tense electromagnetic pulses of astrophysical origin can lead to very energetic photons via potential'' associated with the envelope of the electromagnetic pulse [3]. The resulting temporary energy

  14. Electron density measurements of atmospheric-pressure non-thermal N{sub 2} plasma jet by Stark broadening and irradiance intensity methods

    SciTech Connect (OSTI)

    Xiao, Dezhi; Shen, Jie; Lan, Yan; Xie, Hongbing; Shu, Xingsheng; Meng, Yuedong; Li, Jiangang [Institute of Plasma Physics, Chinese Academy of Sciences, P. O. Box 1126, Hefei 230031 (China); Cheng, Cheng, E-mail: chengcheng@ipp.ac.cn, E-mail: paul.chu@cityu.edu.hk [Institute of Plasma Physics, Chinese Academy of Sciences, P. O. Box 1126, Hefei 230031 (China); Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Chu, Paul K., E-mail: chengcheng@ipp.ac.cn, E-mail: paul.chu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China)

    2014-05-15T23:59:59.000Z

    An atmospheric-pressure non-thermal plasma jet excited by high frequency alternating current using nitrogen is developed and the electron density in the active region of this plasma jet is investigated by two different methods using optical emission spectroscopy, Stark broadening, and irradiance intensity method. The irradiance intensity method shows that the average electron density is about 10{sup 20}/m{sup 3} which is slightly smaller than that by the Stark broadening method. However, the trend of the change in the electron density with input power obtained by these two methods is consistent.

  15. HOT ELECTRON ENERGY DISTRIBUTIONS FROM ULTRA-INTENSE LASER SOLID INTERACTIONS

    SciTech Connect (OSTI)

    Chen, H; Wilks, S C; Kruer, W; Patel, P; Shepherd, R

    2008-10-08T23:59:59.000Z

    Measurements of electron energy distributions from ultra-intense (>10{sup 19} W/cm{sup 2}) laser-solid interactions using an electron spectrometer are presented. These measurements were performed on the Vulcan petawatt laser at Rutherford Appleton Laboratory and the Callisto laser at Lawrence Livermore National Laboratory. The effective hot electron temperatures (T{sub hot}) have been measured for laser intensities (I{lambda}{sup 2}) from 10{sup 18} W/cm{sup 2} {micro}m{sup 2} to 10{sup 21} W/cm{sup 2} {micro}m{sup 2} for the first time, and T{sub hot} is found to increase as (I{lambda}{sup 2}){sup 0.34} {+-} 0.4. This scaling agrees well with the empirical scaling published by Beg et al. (1997), and is explained by a simple physical model that gives good agreement with experimental results and particle-in-cell simulations.

  16. Resonant high-order harmonic generation from plasma ablation: Laser intensity dependence of the harmonic intensity and phase

    SciTech Connect (OSTI)

    Milosevic, D. B. [Faculty of Science, University of Sarajevo, Zmaja od Bosne 35, 71000 Sarajevo (Bosnia and Herzegowina); Max-Born-Institut, Max-Born-Str. 2a, D-12489 Berlin (Germany)

    2010-02-15T23:59:59.000Z

    Experimentally observed strong enhancement of a single high-order harmonic in harmonic generation from low-ionized laser plasma ablation is explained as resonant harmonic generation. The resonant harmonic intensity increases regularly with the increase of the laser intensity, while the phase of the resonant harmonic is almost independent of the laser intensity. This is in sharp contrast with the usual plateau and cutoff harmonics, the intensity of which exhibits wild oscillations while its phase changes rapidly with the laser intensity. The temporal profile of a group of harmonics, which includes the resonant harmonic, has the form of a broad peak in each laser-field half cycle. These characteristics of resonant harmonics can have an important application in attoscience. We illustrate our results using examples of Sn and Sb plasmas.

  17. Ultra-High Resolution Electron Microscopy for Catalyst Characterizatio...

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

    Documents & Publications Ultra-High Resolution Electron Microscopy for Catalyst Characterization Ultra-high Resolution Electron Microscopy for Catalyst Characterization...

  18. Electron acceleration by an intense short pulse laser in a static magnetic field in vacuum K. P. Singh*

    E-Print Network [OSTI]

    Roy, Subrata

    Electron acceleration by an intense short pulse laser in a static magnetic field in vacuum K. P by a laser pulse having Gaussian radial and temporal profiles of intensity has been studied in a static to be the same as that of the magnetic field of the laser pulse. The electron gains considerable energy

  19. Electronic and intraband optical properties of single quantum rings under intense laser field radiation

    SciTech Connect (OSTI)

    Radu, A. [Department of Physics, Politehnica University of Bucharest, 313 Splaiul Independentei, Bucharest RO-060042 (Romania); Kirakosyan, A. A.; Baghramyan, H. M.; Barseghyan, M. G., E-mail: mbarsegh@ysu.am [Department of Solid State Physics, Yerevan State University, Alex Manoogian 1, 0025 Yerevan (Armenia); Laroze, D. [Instituto de Alta Investigación, Universidad de Tarapacá, Casilla 7D, Arica (Chile)

    2014-09-07T23:59:59.000Z

    The influence of an intense laser field on one-electron states and intraband optical absorption coefficients is investigated in two-dimensional GaAs/Ga{sub 0.7}Al{sub 0.3}As quantum rings. An analytical expression of the effective lateral confining potential induced by the laser field is obtained. The one-electron energy spectrum and wave functions are found using the effective mass approximation and exact diagonalization technique. We have shown that changes in the incident light polarization lead to blue- or redshifts in the intraband optical absorption spectrum. Moreover, we found that only blueshift is obtained with increasing outer radius of the quantum ring.

  20. HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS

    SciTech Connect (OSTI)

    Bieniosek, F.M.; Henestroza, E.; Leitner, M.; Logan, B.G.; More, R.M.; Roy, P.K.; Ni, P.; Seidl, P.A.; Waldron, W.L.; Barnard, J.J.

    2008-08-01T23:59:59.000Z

    The US heavy ion fusion science program has developed techniques for heating ion-beam-driven warm dense matter (WDM) targets. The WDM conditions are to be achieved by combined longitudinal and transverse space-charge neutralized drift compression of the ion beam to provide a hot spot on the target with a beam spot size of about 1 mm, and pulse length about 1-2 ns. As a technique for heating volumetric samples of matter to high energy density, intense beams of heavy ions are capable of delivering precise and uniform beam energy deposition dE/dx, in a relatively large sample size, and the ability to heat any solid-phase target material. Initial experiments use a 0.3 MeV K+ beam (below the Bragg peak) from the NDCX-I accelerator. Future plans include target experiments using the NDCX-II accelerator, which is designed to heat targets at the Bragg peak using a 3-6 MeV lithium ion beam. The range of the beams in solid matter targets is about 1 micron, which can be lengthened by using porous targets at reduced density. We have completed the fabrication of a new experimental target chamber facility for WDM experiments, and implemented initial target diagnostics to be used for the first target experiments in NDCX-1. The target chamber has been installed on the NDCX-I beamline. The target diagnostics include a fast multi-channel optical pyrometer, optical streak camera, VISAR, and high-speed gated cameras. Initial WDM experiments will heat targets by compressed NDCX-I beams and will explore measurement of temperature and other target parameters. Experiments are planned in areas such as dense electronegative targets, porous target homogenization and two-phase equation of state.

  1. High pressure generation by hot electrons driven ablation

    SciTech Connect (OSTI)

    Piriz, A. R. [E.T.S.I. Industriales, CYTEMA, and Instituto de Investigaciones Energéticas, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain)] [E.T.S.I. Industriales, CYTEMA, and Instituto de Investigaciones Energéticas, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Piriz, S. A. [Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid (Spain)] [Facultad de Ciencias Físicas, Universidad Complutense de Madrid, 28040 Madrid (Spain); Tahir, N. A. [GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt (Germany)] [GSI Helmholtzzentrum für Schwerionenforschung, Planckstrasse 1, 64291 Darmstadt (Germany)

    2013-11-15T23:59:59.000Z

    A previous model [Piriz et al. Phys. Plasmas 19, 122705 (2012)] for the ablation driven by the hot electrons generated in collisionless laser-plasma interactions in the framework of shock ignition is revisited. The impact of recent results indicating that for a laser wavelength ? = 0.35 ?m the hot electron temperature ?{sub H} would be independent of the laser intensity I, on the resulting ablation pressure is considered. In comparison with the case when the scaling law ?{sub H}?(I?{sup 2}){sup 1/3} is assumed, the generation of the high pressures needed for driving the ignitor shock may be more demanding. Intensities above 10{sup 17} W/cm{sup 2} would be required for ?{sub H}=25?30 keV.

  2. Electron-impact excitation collision strengths and theoretical line intensities for transitions in S III

    SciTech Connect (OSTI)

    Grieve, M. F. R.; Ramsbottom, C. A.; Hudson, C. E. [Centre for Theoretical Atomic, Molecular and Optical Physics, School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN (United Kingdom); Keenan, F. P., E-mail: c.ramsbottom@qub.ac.uk [Astrophysics Research Centre, School of Mathematics and Physics, Queen's University Belfast, Belfast, BT7 1NN (United Kingdom)

    2014-01-01T23:59:59.000Z

    We present Maxwellian-averaged effective collision strengths for the electron-impact excitation of S III over a wide range of electron temperatures of astrophysical importance, log T{sub e} (K) = 3.0-6.0. The calculation incorporates 53 fine-structure levels arising from the six configurations—3s {sup 2}3p {sup 2}, 3s3p {sup 3}, 3s {sup 2}3p3d, 3s {sup 2}3p4s, 3s {sup 2}3p4p, and 3s {sup 2}3p4d—giving rise to 1378 individual lines and is undertaken using the recently developed RMATRX II plus FINE95 suite of codes. A detailed comparison is made with a previous R-matrix calculation and significant differences are found for some transitions. The atomic data are subsequently incorporated into the modeling code CLOUDY to generate line intensities for a range of plasma parameters, with emphasis on allowed ultraviolet extreme-ultraviolet emission lines detected from the Io plasma torus. Electron density-sensitive line ratios are calculated with the present atomic data and compared with those from CHIANTI v7.1, as well as with Io plasma torus spectra obtained by Far-Ultraviolet Spectroscopic Explorer and Extreme-Ultraviolet Explorer. The present line intensities are found to agree well with the observational results and provide a noticeable improvement on the values predicted by CHIANTI.

  3. Max Tech and Beyond: High-Intensity Discharge Lamps

    SciTech Connect (OSTI)

    Scholand, Michael

    2012-04-01T23:59:59.000Z

    High-intensity discharge (HID) lamps are most often found in industrial and commercial applications, and are the light source of choice in street and area lighting, and sports stadium illumination. HID lamps are produced in three types - mercury vapor (MV), high pressure sodium (HPS) and metal halide (MH). Of these, MV and MH are considered white-light sources (although the MV exhibits poor color rendering) and HPS produces a yellow-orange color light. A fourth lamp, low-pressure sodium (LPS), is not a HID lamp by definition, but it is used in similar applications and thus is often grouped with HID lamps. With the notable exception of MV which is comparatively inefficient and in decline in the US from both a sales and installed stock point of view; HPS, LPS and MH all have efficacies over 100 lumens per watt. The figure below presents the efficacy trends over time for commercially available HID lamps and LPS, starting with MV and LPS in 1930's followed by the development of HPS and MH in the 1960's. In HID lamps, light is generated by creating an electric arc between two electrodes in an arc tube. The particles in the arc are partially ionized, making them electrically conductive, and a light-emitting 'plasma' is created. This arc occurs within the arc tube, which for most HID lamps is enclosed within an evacuated outer bulb that thermally isolates and protects the hot arc tube from the surroundings. Unlike a fluorescent lamp that produces visible light through down-converting UV light with phosphors, the arc itself is the light source in an HID lamp, emitting visible radiation that is characteristic of the elements present in the plasma. Thus, the mixture of elements included in the arc tube is one critical factor determining the quality of the light emitted from the lamp, including its correlated color temperature (CCT) and color rendering index (CRI). Similar to fluorescent lamps, HID lamps require a ballast to start and maintain stable operating conditions, and this necessitates additional power beyond that used by the lamp itself. HID lamps offer important advantages compared to other lighting technologies, making them well suited for certain applications. HID lamps can be very efficient, have long operating lives, are relatively temperature-insensitive and produce a large quantity of light from a small package. For these reasons, HID lamps are often used when high levels of illumination are required over large areas and where operating and maintenance costs must be kept to a minimum. Furthermore, if the installation has a significant mounting height, high-power HID lamps can offer superior optical performance luminaires, reducing the number of lamps required to illuminate a given area. The indoor environments best suited to HID lamps are those with high ceilings, such as those commonly found in industrial spaces, warehouses, large retail spaces, sports halls and large public areas. Research into efficacy improvements for HID lighting technologies has generally followed market demand for these lamps, which is in decline for MV and LPS, has reached a plateau for HPS and is growing for MH. Several manufacturers interviewed for this study indicated that although solid-state lighting was now receiving the bulk of their company's R&D investment, there are still strong HID lamp research programs, which concentrate on MH technologies, with some limited amount of investment in HPS for specific niche applications (e.g., agricultural greenhouses). LPS and MV lamps are no longer being researched or improved in terms of efficacy or other performance attributes, although some consider MH HID lamps to be the next-generation MV lamp. Thus, the efficacy values of commercially available MV, LPS and HPS lamps are not expected to increase in the next 5 to 10 years. MH lamps, and more specifically, ceramic MH lamps are continuing to improve in efficacy as well as light quality, manufacturability and lamp life. Within an HID lamp, the light-producing plasma must be heated to sufficiently high temperatures to achieve high efficiencie

  4. OBSERBATION OF HIGH INTENSITY X-RAYS IN INVERSE COMPTON SCATTERING EXPERIMENT

    E-Print Network [OSTI]

    OBSERBATION OF HIGH INTENSITY X-RAYS IN INVERSE COMPTON SCATTERING EXPERIMENT S. Kashiwagi, M the first results of high intensity x-ray generation using Inverse Laser Compton scattering. This experiment Synchrotron Source (LSS). It is based on inverse Compton scattering via interaction between pulsed high power

  5. Deep Trek High Temperature Electronics Project

    SciTech Connect (OSTI)

    Bruce Ohme

    2007-07-31T23:59:59.000Z

    This report summarizes technical progress achieved during the cooperative research agreement between Honeywell and U.S. Department of Energy to develop high-temperature electronics. Objects of this development included Silicon-on-Insulator (SOI) wafer process development for high temperature, supporting design tools and libraries, and high temperature integrated circuit component development including FPGA, EEPROM, high-resolution A-to-D converter, and a precision amplifier.

  6. Commissioning the new high power rf system for the AGS with high intensity beam

    SciTech Connect (OSTI)

    Brennan, J.M.; Ciardullo, D.J.; Deng, D.P; Hayes, T.; Onillon, E.; Otis, A.; Sanders, R.T.; Zaltsman, A.

    1994-08-01T23:59:59.000Z

    A new high power rf system has been installed in the AGS in order to raise the beam loading limit to beyond 6 {times} 10{sup 13} protons per pulse. The old system was limited to 2.2 {times} 10{sup l3} ppp by: available real power, multi-loop instability, and transient beam loading during batch filling from the Booster. The key components of the new system are: new power amplifiers in the tunnel using the Thomson-CSF TH573 300kW tetrode, rf feedback around the power stage, and reduction of the 10 cavities` R/Q by 1.8 by additional gap capacitors. Commissioning of the new rf system with high intensity beam is described. The intensity goal for the 1994 running period is 4 {times} 10{sup 13} ppp. To date, 3.7 {times} 10{sup 13} ppp has been achieved.

  7. Ultra-high Resolution Electron Microscopy for Catalyst Characterizatio...

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

    high Resolution Electron Microscopy for Catalyst Characterization Ultra-high Resolution Electron Microscopy for Catalyst Characterization 2009 DOE Hydrogen Program and Vehicle...

  8. Ultra-High Resolution Electron Microscopy for Catalyst Characterizatio...

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

    Documents & Publications Ultra-High Resolution Electron Microscopy for Catalyst Characterization Ultra-high Resolution Electron Microscopy for Catalyst Characterization Catalyst...

  9. High Dialectric Constant Capacitors for Power Electronic Systems...

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

    High Dialectric Constant Capacitors for Power Electronic Systems High Dialectric Constant Capacitors for Power Electronic Systems 2012 DOE Hydrogen and Fuel Cells Program and...

  10. High-Dialectric-Constant Capacitors for Power Electronic Systems...

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

    High-Dialectric-Constant Capacitors for Power Electronic Systems High-Dialectric-Constant Capacitors for Power Electronic Systems 2011 DOE Hydrogen and Fuel Cells Program, and...

  11. Electron Generation and Transport in Intense Relativistic Laser-Plasma Interactions Relevant to Fast Ignition ICF

    SciTech Connect (OSTI)

    Ma, T

    2010-04-21T23:59:59.000Z

    The reentrant cone approach to Fast Ignition, an advanced Inertial Confinement Fusion scheme, remains one of the most attractive because of the potential to efficiently collect and guide the laser light into the cone tip and direct energetic electrons into the high density core of the fuel. However, in the presence of a preformed plasma, the laser energy is largely absorbed before it can reach the cone tip. Full scale fast ignition laser systems are envisioned to have prepulses ranging between 100 mJ to 1 J. A few of the imperative issues facing fast ignition, then, are the conversion efficiency with which the laser light is converted to hot electrons, the subsequent transport characteristics of those electrons, and requirements for maximum allowable prepulse this may put on the laser system. This dissertation examines the laser-to-fast electron conversion efficiency scaling with prepulse for cone-guided fast ignition. Work in developing an extreme ultraviolet imager diagnostic for the temperature measurements of electron-heated targets, as well as the validation of the use of a thin wire for simultaneous determination of electron number density and electron temperature will be discussed.

  12. A High Intensity Positron Source at Saclay: The SOPHI Project

    SciTech Connect (OSTI)

    Rey, J.-M.; Blideanu, V.; Carty, M.; Coulloux, G.; Curtoni, A.; Delferriere, O.; Liszkay, L.; Perez, P.; Ruiz, N.; Sauce, Y. [CEA-Saclay, DSM/IRFU, 91191 Gif sur Yvette (France); Forest, F.; Lancelot, J. L.; Neuveglise, D. [SIGMAPHI, Z.I. du Prat, Rue des freres Montgolfier, Vannes, Morbihan 56000 (France)

    2009-03-10T23:59:59.000Z

    We are building the SOPHI experiment in Saclay, which is a device based on a small 5 MeV electron linac to produce positrons via pair production on a tungsten target. This device should provide 10{sup 8} slow e{sup +}/s, i.e. a factor 300 greater than the strongest activity Na{sub 22} based setup. The SOPHI system has been finalized at the end of 2006 and the main components have been studied and built during 2007. The experiment is currently being assembled and first results are expected for autumn 2008. The electron linac, positron beam production and transport system will be presented, and expected positron production rate reported.

  13. Generation of Stable (3+1)-dimensional High-intensity Ultrashort Light Pulses

    SciTech Connect (OSTI)

    Todorov, T. P.; Koprinkov, I. G. [Department of Applied Physics, Technical University of Sofia, 1000 Sofia (Bulgaria); Todorova, M. E. [College of Energetics and Electronics, Technical University of Sofia, 1000 Sofia (Bulgaria); Todorov, M. D. [Faculty of Appl. Math. and Informatics, Technical University of Sofia, 1000 Sofia (Bulgaria)

    2010-11-25T23:59:59.000Z

    The spatiotemporal dynamics of high-intensity femtosecond laser pulses is studied within a rigorous physical model. The pulse propagation is described by the nonlinear envelope equation. The propagation and the material equations are solved self-consistently at realistic physical conditions. Self-compression of the pulse around single-cycle regime and dramatic increase of the pulse intensity is found. At certain conditions, the peak intensity, transversal width, time duration, and the spatiotemporal pulse shape remain stable with the propagation of the pulse, resembling a soliton formation process. This, to our knowledge, is the first simulation of high-intensity ultrashort soliton formation dynamics in the (3+1)-dimensional case.

  14. HIGH INTENSITY LOW-ENERGY POSITRON SOURCE AT JEFFERSON

    SciTech Connect (OSTI)

    Serkan Golge, Bogdan Wojtsekhowski, Branislav Vlahovic

    2012-07-01T23:59:59.000Z

    We present a novel concept of a low-energy e{sup +} source with projected intensity on the order of 10{sup 10} slow e{sup +}/s. The key components of this concept are a continuous wave e{sup -} beam, a rotating positron-production target, a synchronized raster/anti-raster, a transport channel, and extraction of e{sup +} into a field-free area through a magnetic plug for moderation in a cryogenic solid. Components were designed in the framework of GEANT4-based (G4beamline) Monte Carlo simulation and TOSCA magnetic field calculation codes. Experimental data to demonstrate the effectiveness of the magnetic plug is presented.

  15. High intensity proton acceleration at the Brookhaven AGS -- An update

    SciTech Connect (OSTI)

    Ahrens, L.; Alessi, J.; Blaskiewicz, M. [Brookhaven National Lab., Upton, NY (United States). AGS Dept.] [and others

    1997-07-01T23:59:59.000Z

    The AGS accelerator complex is into its third year of 60+ {times} 10{sup 12} (teraproton = Tp) per cycle operation. The hardware making up the complex as configured in 1997 is briefly mentioned. The present level of accelerator performance is discussed. This includes beam transfer efficiencies at each step in the acceleration process, i.e. losses; which are a serious issue at this intensity level. Progress made in understanding beam behavior at the Linac-to-Booster (LtB) injection, at the Booster-to-AGS (BtA) transfer as well as across the 450 ms AGS accumulation porch is presented. The state of transition crossing, with the gamma-tr jump is described. Coherent effects including those driven by space charge are important at all of these steps.

  16. 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.

  17. HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS

    E-Print Network [OSTI]

    Bieniosek, F.M.

    2008-01-01T23:59:59.000Z

    used to inject plasma into the final focus region right inplasma flow is slowed down once entering the high field region of the final focus

  18. HIGH ENERGY DENSITY PHYSICS EXPERIMENTS WITH INTENSE HEAVY ION BEAMS

    E-Print Network [OSTI]

    Henestroza, E.

    2012-01-01T23:59:59.000Z

    used to inject plasma into the final focus region right inplasma flow is slowed down once entering the high field region of the final focus

  19. Streaking at high energies with electrons and positrons

    SciTech Connect (OSTI)

    Ipp, Andreas; Evers, Joerg; Keitel, Christoph H.; Hatsagortsyan, Karen Z. [Institut fuer Theoretische Physik, Technische Universitaet Wien, 1040 Vienna (Austria); Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)

    2012-07-09T23:59:59.000Z

    State-of-the-art attosecond metrology deals with the detection and characterization of photon pulses with typical energies up to the hundreds of eV and time resolution of several tens of attoseconds. Such short pulses are used for example to control the motion of electrons on the atomic scale or to measure inner-shell atomic dynamics. The next challenge of time-resolving the inner-nuclear dynamics, transient meson states and resonances requires photon pulses below attosecond duration and with energies exceeding the MeV scale. Here we discuss a detection scheme for time-resolving high-energy gamma ray pulses down to the zeptosecond timescale. The scheme is based on the concept of attosecond streak imaging, but instead of conversion of photons into electrons in a nonlinear medium, the high-energy process of electron-positron pair creation is utilized. These pairs are produced in vacuum through the collision of a test pulse to be characterized with an intense laser pulse, and they acquire additional energy and momentum depending on their phase in the streaking pulse at the moment of production. A coincidence measurement of the electron and positron momenta after the interaction provides information on the pair production phase within the streaking pulse. We examine the limitations imposed by quantum radiation reaction in multiphoton Compton scattering on this detection scheme, and discuss other necessary conditions to render the scheme feasible in the upcoming Extreme Light Infrastructure (ELI) laser facility.

  20. Emittance growth of an nonequilibrium intense electron beam in a transport channel with discrete focusing

    SciTech Connect (OSTI)

    Carlsten, B.E.

    1997-02-01T23:59:59.000Z

    The author analyzes the emittance growth mechanisms for a continuous, intense electron beam in a focusing transport channel, over distances short enough that the beam does not reach equilibrium. The emittance grows from the effect of nonlinear forces arising from (1) current density nonuniformities, (2) energy variations leading to nonlinearities in the space-charge force even if the current density is uniform, (3) axial variations in the radial vector potential, (4) an axial velocity shear along the beam, and (5) an energy redistribution of the beam as the beam compresses or expands. The emittance growth is studied analytically and numerically for the cases of balanced flow, tight focusing, and slight beam scalloping, and is additionally studied numerically for an existing 6-MeV induction linear accelerator. Rules for minimizing the emittance along a beamline are established. Some emittance growth will always occur, both from current density nonuniformities that arise along the transport and from beam radius changes along the transport.

  1. FETSHIPSTER (Front End Test Stand High Intensity Proton Source for

    E-Print Network [OSTI]

    McDonald, Kirk

    . · Activated samples would be supplied to collaborating institutes for post irradiation examination to a water cooled back plate Main Challenges ­ Potentially high heat flux to cooling water Pulsed power density results in unsteady sample temperature Temperature difference between sample and cooling plate

  2. Probing the spectral and temporal structures of high-order harmonic generation in intense laser pulses

    E-Print Network [OSTI]

    Chu, Shih-I

    understanding of the origin of the har- monics with energies much in excess of the ionization po- tential Ip of the electronic wave packet with the parent ionic core. Based on this model, the cutoff energy is predicted in intense pulsed laser fields. Accurate time-dependent wave functions are obtained by means of the time

  3. Improved Heat Transfer and Performance of High Intensity Combustion Systems for Reformer Furnace Applications

    E-Print Network [OSTI]

    Williams, F. D. M.; Kondratas, H. M.

    1983-01-01T23:59:59.000Z

    and should enable substantial capital cost savings in new furnace applications. Recent performance improvements established from tests of high intensity combustion systems are described along with advances made in the analytical prediction of design...

  4. Neutralized Drift Compression Experiments (NDCX) with a High Intensity Ion Beam

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    a High Intensity Ion Beam P. K. Roy 1* , S. S. Yu 1 , W. L.12 , 043102 (2005). [6] P. K. Roy et al. , Nucl. Instrum.2005), p.4006. [16] P. K. Roy, S. S. Yu, E. Henestroza, A.

  5. Industrial Application of High Combustion Intensity Systems and Energy Conservation Implications

    E-Print Network [OSTI]

    Williams, F. D. M.; Anderson, L. E.

    1982-01-01T23:59:59.000Z

    process are quantified for vortex stabilized systems. Design analyses of the fuel injectors used with gaseous, liquid and pulverized coal fuels are also presented. The resulting high intensity combustion systems evolved are illustrated with photographs...

  6. 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...

  7. High Dialectric Constant Capacitors for Power Electronic Systems...

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

    Dialectric Constant Capacitors for Power Electronic Systems High Dialectric Constant Capacitors for Power Electronic Systems 2010 DOE Vehicle Technologies and Hydrogen Programs...

  8. Modelling gamma-ray photon emission and pair production in high-intensity laser–matter interactions

    SciTech Connect (OSTI)

    Ridgers, C.P. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU (United Kingdom) [Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU (United Kingdom); Central Laser Facility, STFC Rutherford-Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom); Kirk, J.G. [Max-Planck-Institut für Kernphysik, Postfach 10 39 80, 69029 Heidelberg (Germany)] [Max-Planck-Institut für Kernphysik, Postfach 10 39 80, 69029 Heidelberg (Germany); Duclous, R. [Commissariat ŕ l'Energie Atomique, DAM DIF, F-91297 Arpajon (France)] [Commissariat ŕ l'Energie Atomique, DAM DIF, F-91297 Arpajon (France); Blackburn, T.G. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU (United Kingdom)] [Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU (United Kingdom); Brady, C.S.; Bennett, K.; Arber, T.D. [Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry, CV4 7AL (United Kingdom)] [Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry, CV4 7AL (United Kingdom); Bell, A.R. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU (United Kingdom) [Clarendon Laboratory, University of Oxford, Parks Road, Oxford, OX1 3PU (United Kingdom); Central Laser Facility, STFC Rutherford-Appleton Laboratory, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom)

    2014-03-01T23:59:59.000Z

    In high-intensity (>10{sup 21} Wcm{sup ?2}) laser–matter interactions gamma-ray photon emission by the electrons can strongly affect the electron's dynamics and copious numbers of electron–positron pairs can be produced by the emitted photons. We show how these processes can be included in simulations by coupling a Monte Carlo algorithm describing the emission to a particle-in-cell code. The Monte Carlo algorithm includes quantum corrections to the photon emission, which we show must be included if the pair production rate is to be correctly determined. The accuracy, convergence and energy conservation properties of the Monte Carlo algorithm are analysed in simple test problems.

  9. Highly integrated electronics for the star TPC

    SciTech Connect (OSTI)

    Arthur, A.A.; Bieser, F.; Hearn, W.; Kleinfelder, S.; Merrick, T.; Millaud, J.; Noggle, T.; Rai, G.; Ritter, H.G.; Wieman, H. [Lawrence Berkeley Laboratory, CA (United States)

    1991-12-31T23:59:59.000Z

    The concept for the STAR TPC front-end electronics is presented and the progress toward the development of a fully integrated solution is described. It is the goal of the R+D program to develop the complete electronics chain for the STAR central TPC detector at RHIC. It is obvious that solutions chosen e.g. for ALEPH are not adequate for the 150000 channels that need to be instrumented for readout. It will be necessary to perform all the signal processing, digitization and multiplexing directly on the detector in order to reduce per channel cost and the amount of cabling necessary to read out the information. We follow the approach chosen by the EOS TPC project, where the readout electronics on the detector consists of an integrated preamplifier, a hybrid shaping amplifier, an integrated switched capacitor array and a highly multiplexed ADC. The STAR electronics will be further integrated so that approximately 16 channels of the preamplifier, the shaper, the analog store and the ADC will be contained in two integrated circuits located directly on the pad plane.

  10. Resonator Modes in High Gain Free Electron Lasers

    E-Print Network [OSTI]

    Xie, M.

    2010-01-01T23:59:59.000Z

    of Optical Guiding in Free Electron Lasers", Department ofModes in High Gain Free Electron Lasers M. Xie. D.A.O.International Free Electron Laser Conference. Naples. FL.

  11. Extremely high frequency RF effects on electronics.

    SciTech Connect (OSTI)

    Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale; Williams, Jeffery Thomas; Wouters, Gregg A.; Bacon, Larry Donald; Mar, Alan

    2012-01-01T23:59:59.000Z

    The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit board traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.

  12. Electronic and structural response of InSb to ultra-short and ultra-intense laser pulses

    E-Print Network [OSTI]

    Burzo, Andrea Mihaela

    2001-01-01T23:59:59.000Z

    of the behavior of InSb following application of ultra-short and ultra-intense laser pulses. Motivated directly by these experiments, we have performed simulations of the electron-ion dynamics of InSb subjected to femtosecond-scale laser pulses. These simulations...

  13. Overview of the High Intensity Neutrino Source Linac R&D program at Fermilab

    SciTech Connect (OSTI)

    Webber, R.C.; Appollinari, G.; Carneiro, J.P.; Gonin, I.; Hanna, B.; Hays, S.; Khabiboulline, T.; Lanfranco, G.; Madrak, R.L.; Moretti, A.; Nicol, T.; /Fermilab /Argonne

    2008-09-01T23:59:59.000Z

    The Fermilab High Intensity Neutrino Source (HINS) Linac R&D program is building a first-of-a-kind 60 MeV superconducting H- linac. The HINS Linac incorporates superconducting solenoids for transverse focusing, high power RF vector modulators for independent control of multiple cavities powered from a single klystron, and superconducting spoke-type accelerating cavities starting at 10 MeV. This will be the first application and demonstration of any of these technologies in a low-energy, high-intensity proton/H- linear accelerator. The HINS effort is relevant to a high intensity, superconducting H- linac that might serve the next generation of neutrino physics and muon storage ring/collider experiments. An overview of the HINS program, machine design, status, and outlook is presented.

  14. Electron scattering and nonlinear trapping by oblique whistler waves: The critical wave intensity for nonlinear effects

    SciTech Connect (OSTI)

    Artemyev, A. V., E-mail: ante0226@gmail.com; Vasiliev, A. A. [Space Research Institute, RAS, Moscow (Russian Federation); Mourenas, D.; Krasnoselskikh, V. V. [LPC2E/CNRS—University of Orleans, Orleans (France); Agapitov, O. V. [Space Sciences Laboratory, University of California, Berkeley, California 94720 (United States)

    2014-10-15T23:59:59.000Z

    In this paper, we consider high-energy electron scattering and nonlinear trapping by oblique whistler waves via the Landau resonance. We use recent spacecraft observations in the radiation belts to construct the whistler wave model. The main purpose of the paper is to provide an estimate of the critical wave amplitude for which the nonlinear wave-particle resonant interaction becomes more important than particle scattering. To this aim, we derive an analytical expression describing the particle scattering by large amplitude whistler waves and compare the corresponding effect with the nonlinear particle acceleration due to trapping. The latter is much more rare but the corresponding change of energy is substantially larger than energy jumps due to scattering. We show that for reasonable wave amplitudes ?10–100?mV/m of strong whistlers, the nonlinear effects are more important than the linear and nonlinear scattering for electrons with energies ?10–50?keV. We test the dependencies of the critical wave amplitude on system parameters (background plasma density, wave frequency, etc.). We discuss the role of obtained results for the theoretical description of the nonlinear wave amplification in radiation belts.

  15. Proposal for a High-Brightness Pulsed Electron Source

    SciTech Connect (OSTI)

    Zolotorev, M.; Commins, E.D.; Heifets, S.; Sannibale, F.; /LBL, Berkeley /UC, Berkeley /SLAC

    2006-10-16T23:59:59.000Z

    We propose a novel scheme for a high-brightness pulsed electron source, which has the potential for many useful applications in electron microscopy, inverse photo-emission, low energy electron scattering experiments, and electron holography. A description of the proposed scheme is presented.

  16. A summary of high-temperature electronics research and development

    SciTech Connect (OSTI)

    Thome, F.V.; King, D.B.

    1991-10-18T23:59:59.000Z

    Current and future needs in automative, aircraft, space, military, and well logging industries require operation of electronics at higher temperatures than today's accepted limit of 395 K. Without the availability of high-temperature electronics, many systems must operate under derated conditions or must accept severe mass penalties required by coolant systems to maintain electronic temperatures below critical levels. This paper presents ongoing research and development in the electronics community to bring high-temperature electronics to commercial realization. Much of this work was recently reviewed at the First International High-Temperature Electronics Conference held 16--20 June 1991 in Albuquerque, New Mexico. 4 refs., 1 tab.

  17. High harmonic generation from Bloch electrons in solids

    E-Print Network [OSTI]

    Wu, Mengxi; Reis, David A; Schafer, Kenneth J; Gaarde, Mette B

    2015-01-01T23:59:59.000Z

    We study the generation of high harmonic radiation by Bloch electrons in a model transparent solid driven by a strong mid-infrared laser field. We solve the single-electron time-dependent Schr\\"odinger equation (TDSE) using a velocity-gauge method [New J. Phys. 15, 013006 (2013)] that is numerically stable as the laser intensity and number of energy bands are increased. The resulting harmonic spectrum exhibits a primary plateau due to the coupling of the valence band to the first conduction band, with a cutoff energy that scales linearly with field strength and laser wavelength. We also find a weaker second plateau due to coupling to higher-lying conduction bands, with a cutoff that is also approximately linear in the field strength. To facilitate the analysis of the time-frequency characteristics of the emitted harmonics, we also solve the TDSE in a time-dependent basis set, the Houston states [Phys. Rev. B 33, 5494 (1986)], which allows us to separate inter-band and intra-band contributions to the time-depe...

  18. Backward-Propagating MeV Electrons in Ultra-Intense Laser Interactions: Standing Wave Acceleration and Coupling to the Reflected Laser Pulse

    E-Print Network [OSTI]

    Orban, Chris; Chowdhury, Enam D; Nees, John A; Frische, Kyle; Roquemore, W Melvyn

    2014-01-01T23:59:59.000Z

    Laser-accelerated electron beams have been created at a kHz repetition rate from the reflection of intense ($\\sim10^{18}$ W/cm$^2$), 30 fs laser pulses focused on a continuous water-jet in an experiment at the Air Force Research Laboratory. This paper investigates Particle-In-Cell (PIC) simulations of the laser-target interaction to identify the physical mechanisms of electron acceleration in this experiment. We find that the standing-wave pattern created by the overlap of the incident and reflected laser is particularly important because this standing wave "injects" electrons into the reflected laser pulse where the electrons are further accelerated. We identify two regimes of standing wave acceleration: a highly relativistic case ($a_0~\\geq~1$), and a moderately relativistic case ($a_0~\\sim~0.5$) which operates over a larger fraction of the laser period. Previous work by other groups investigated the highly relativistic case for its usefulness in launching electrons in the forward direction. We extend this ...

  19. Fiber Bragg grating inscription by high-intensity femtosecond UV laser light: comparison

    E-Print Network [OSTI]

    Nikogosyan, David N.

    Fiber Bragg grating inscription by high-intensity femtosecond UV laser light: comparison with other 264-nm laser light and a phase mask technique, Bragg grating inscription in a range of different, that result in a significant photosensitivity enhancement of the in- vestigated fibers in comparison

  20. ECOS-LINCE: A HIGH INTENSITY MULTI-ION SUPERCONDUCTING LINAC FOR NUCLEAR STRUCTURE AND REACTIONS

    E-Print Network [OSTI]

    Boyer, Edmond

    ECOS-LINCE: A HIGH INTENSITY MULTI-ION SUPERCONDUCTING LINAC FOR NUCLEAR STRUCTURE AND REACTIONS I as part of the Long-Range Plan of the Nuclear-Physics community. LINCE will be a multi-user facility dedicated to ECOS science: fundamental physics, astrophysics, nuclear structure and reaction dynamics

  1. Investigation of long-period fiber gratings induced by high-intensity femtosecond UV laser pulses

    E-Print Network [OSTI]

    Nikogosyan, David N.

    efficiency with that for other existing meth- ods of recording. We studied the temperature sensing properties changes in the fiber core induced by thermal heating, were developed. They include the use of a CO2 laserInvestigation of long-period fiber gratings induced by high-intensity femtosecond UV laser pulses

  2. Trapping and Destruction of Long-Range High-Intensity Optical Filaments by Molecular Quantum Wakes in Air

    E-Print Network [OSTI]

    Milchberg, Howard

    in Air S. Varma, Y.-H. Chen, and H. M. Milchberg Institute for Research in Electronics and Applied in atmospheric air on the long-range filamentary propagation of intense femtosecond laser pulses. In a pump following a pump pulse filamenting in air has a dramatic effect on the propagation of an intense probe pulse

  3. Electronic high voltage generator with a high temperature superconducting coil

    SciTech Connect (OSTI)

    Jin, J.X.; Liu, H.K.; Dou, S.X. [Univ. of Wollongong (Australia)] [and others

    1996-12-31T23:59:59.000Z

    A novel method for generating high voltages from a low voltage DC source, by using a capacitor and inductor in a R, L, C resonant circuit has been developed with the consideration of using a high temperature superconducting (HTS) coil. To generate high voltages the polarity of a low voltage battery source is reversed each half resonant cycle, the control being achieved by an electronic switch. Resistance in the circuit limits the voltages that can be built up. By replacing a copper winding inductor with another inductor which has a HTS winding, the magnitude of achievable voltages is substantially increased. A (Bi,Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+x} multifilament HTS wire is considered in this work to make the superconducting inductor. The high voltages generated are not capable of supplying low impedance loads, however, possible applications of the generator include electrical partial discharge testing and insulation resistance testing. It could also be used as a testing method for the HTS itself with respect to the critical current and AC loss measurement.

  4. Observations of beam-beam effects at high intensities in the LHC

    E-Print Network [OSTI]

    Herr, W; Laface, E; Papotti, G; Pieloni, T; Alemany-Fernandez, R; Giachino, R; Schaumann, M

    2011-01-01T23:59:59.000Z

    First observations with colliding beams in the LHC with bunch intensities close to nominal and above are reported. In 2010 the LHC initially operated with few bunches spaced around the circumference. Beam-beam tune shifts exceeding significantly the design value have been observed. In a later stage crossing angles were introduced around the experiments to allow the collisions of bunch trains. We report the first experience with head-on as well as long range interactions of high intensity bunches and discuss the possible performance reach

  5. Adapting High Brightness Relativistic Electron Beams for Ultrafast Science

    E-Print Network [OSTI]

    Scoby, Cheyne Matthew

    2012-01-01T23:59:59.000Z

    for material removal in ultra- fast pulsed laser ablation ofspecifically the ultra- fast laser-induced melting of gold.of an ultra- short, high intensity laser pulse pumping a

  6. High Beta Observations of the Hot Electron Interchange Instability

    E-Print Network [OSTI]

    High Beta Observations of the Hot Electron Interchange Instability E.E. Ortiz, M.E. Mauel, D observed in high-beta plasma created in the Levitated Dipole Experiment (LDX). We have previously of anisotropic high beta equilibrium · Measuring Electrostatic Fluctuations · Hot Electron Interchange (HEI

  7. Measurement and interpretation of threshold stress intensity factors for steels in high-pressure hydrogen gas.

    SciTech Connect (OSTI)

    Dadfarnia, Mohsen (University of Illinois at Urbana-Champaign, Urbana, IL); Nibur, Kevin A.; San Marchi, Christopher W.; Sofronis, Petros (University of Illinois at Urbana-Champaign, Urbana, IL); Somerday, Brian P.; Foulk, James W., III; Hayden, Gary A. (CP Industries, McKeesport, PA)

    2010-07-01T23:59:59.000Z

    Threshold stress intensity factors were measured in high-pressure hydrogen gas for a variety of low alloy ferritic steels using both constant crack opening displacement and rising crack opening displacement procedures. The sustained load cracking procedures are generally consistent with those in ASME Article KD-10 of Section VIII Division 3 of the Boiler and Pressure Vessel Code, which was recently published to guide design of high-pressure hydrogen vessels. Three definitions of threshold were established for the two test methods: K{sub THi}* is the maximum applied stress intensity factor for which no crack extension was observed under constant displacement; K{sub THa} is the stress intensity factor at the arrest position for a crack that extended under constant displacement; and K{sub JH} is the stress intensity factor at the onset of crack extension under rising displacement. The apparent crack initiation threshold under constant displacement, K{sub THi}*, and the crack arrest threshold, K{sub THa}, were both found to be non-conservative due to the hydrogen exposure and crack-tip deformation histories associated with typical procedures for sustained-load cracking tests under constant displacement. In contrast, K{sub JH}, which is measured under concurrent rising displacement and hydrogen gas exposure, provides a more conservative hydrogen-assisted fracture threshold that is relevant to structural components in which sub-critical crack extension is driven by internal hydrogen gas pressure.

  8. E-beam ionized channel guiding of an intense relativistic electron beam

    DOE Patents [OSTI]

    Frost, C.A.; Godfrey, B.B.; Kiekel, P.D.; Shope, S.L.

    1988-05-10T23:59:59.000Z

    An IREB is guided through a curved path by ionizing a channel in a gas with electrons from a filament, and confining the electrons to the center of the path with a magnetic field extending along the path. The magnetic field is preferably generated by a solenoid extending along the path. 2 figs.

  9. High Gradient Inverse Free Electron Laser (IFEL) Accelerator

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

    Gradient High energy gain Inverse Free Electron Laser P. Musumeci UCLA Department of Physics and Astronomy On Behalf of the RUBICON collaboration ATF user meeting, BNL, October 6...

  10. Backcoupling of acoustic streaming on the temperature field inside high-intensity discharge lamps

    E-Print Network [OSTI]

    Schwieger, Joerg; Wolff, Marcus; Manders, Freddy; Suijker, Jos

    2015-01-01T23:59:59.000Z

    Operating high-intensity discharge lamps in the high frequency range (20-300 kHz) provides energy-saving and cost reduction potentials. However, commercially available lamp drivers do not make use of this operating strategy because light intensity fluctuations and even lamp destruction are possible. The reason for the fluctuating discharge arc are acoustic resonances in this frequency range that are excited in the arc tube. The acoustic resonances in turn generate a fluid flow that is caused by the acoustic streaming effect. Here, we present a 3D multiphysics model to determine the influence of acoustic streaming on the temperature field in the vicinity of an acoustic eigenfrequency. In that case a transition from stable to instable behavior occurs. The model is able to predict when light flicker can be expected. The results are in very good accordance with accompanying experiments.

  11. Commissioning of the new high-intensity ultracold neutron source at the Paul Scherrer Institut

    E-Print Network [OSTI]

    Bernhard Lauss

    2010-11-17T23:59:59.000Z

    Commissioning of the new high-intensity ultracold neutron (UCN) source at the Paul Scherrer Institut (PSI) has started in 2009. The design goal of this new generation high intensity UCN source is to surpass by a factor of ~100 the current ultracold neutron densities available for fundamental physics research, with the greatest thrust coming from the search for a neutron electric dipole moment. The PSI UCN source is based on neutron production via proton induced lead spallation, followed by neutron thermalization in heavy water and neutron cooling in a solid deuterium crystal to cold and ultracold energies. A successful beam test with up to 2 mA proton beam on the spallation target was conducted recently. Most source components are installed, others being finally mounted. The installation is on the track for the first cool-down and UCN production in 2010.

  12. Ion source choices - an h- source for the high intensity neutrino source

    SciTech Connect (OSTI)

    Moehs, Douglas P.; /Fermilab; Welton, Robert F.; /SNS Project, Oak Ridge; Stockli, Martin P.; Peters, Jens; /DESY; Alessi, James; /Brookhaven

    2006-08-01T23:59:59.000Z

    The High Intensity Neutrino Source (HINS) program at Fermilab (formerly the Proton Driver) aims to develop a multi-mission linear accelerator (LINAC) capable of accelerate H{sup -} ions to 8 GeV. This paper touches on the ion source requirements for the HINS and discusses long pulse length testing of three ion sources which appear to have the capability of meeting these requirements.

  13. Numerical simulations of stripping effects in high-intensity hydrogen ion linacs

    SciTech Connect (OSTI)

    Carneiro, J.-P.; /Fermilab; Mustapha, B.; Ostroumov, P.N.; /Argonne

    2008-12-01T23:59:59.000Z

    Numerical simulations of H{sup -} stripping losses from blackbody radiation, electromagnetic fields, and residual gas have been implemented into the beam dynamics code TRACK. Estimates of the stripping losses along two high-intensity H{sup -} linacs are presented: the Spallation Neutron Source linac currently being operated at Oak Ridge National Laboratory and an 8 GeV superconducting linac currently being designed at Fermi National Accelerator Laboratory.

  14. Using X-ray free-electron lasers for probing of complex interaction dynamics of ultra-intense lasers with solid matter

    SciTech Connect (OSTI)

    Kluge, T., E-mail: t.kluge@hzdr.de; Huang, L. G.; Metzkes, J.; Bussmann, M. [Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01328 Dresden (Germany)] [Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01328 Dresden (Germany); Gutt, C. [Universität Siegen, D-57068 Siegen (Germany)] [Universität Siegen, D-57068 Siegen (Germany); Schramm, U.; Cowan, T. E. [Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01328 Dresden (Germany) [Helmholtz-Zentrum Dresden-Rossendorf e.V., D-01328 Dresden (Germany); Technische Universität Dresden, D-01062 Dresden (Germany)

    2014-03-15T23:59:59.000Z

    We demonstrate the potential of X-ray free-electron lasers (XFEL) to advance the understanding of complex plasma dynamics by allowing for the first time nanometer and femtosecond resolution at the same time in plasma diagnostics. Plasma phenomena on such short timescales are of high relevance for many fields of physics, in particular in the ultra-intense ultra-short laser interaction with matter. Highly relevant yet only partially understood phenomena become directly accessible in experiment. These include relativistic laser absorption at solid targets, creation of energetic electrons and electron transport in warm dense matter, including the seeding and development of surface and beam instabilities, ambipolar expansion, shock formation, and dynamics at the surfaces or at buried layers. In this paper, we focus on XFEL plasma probing for high power laser matter interactions based on quantitative calculations using synthesized data and evaluate the feasibility of various imaging and scattering techniques with special focus on the small angle X-ray scattering technique.

  15. ISSUANCE 2015-01-26: Energy Conservation Program: Energy Conservation Standards for High-Intensity Lamps, Notice to Reopen Comment Period

    Broader source: Energy.gov [DOE]

    Energy Conservation Program: Energy Conservation Standards for High-Intensity Lamps, Notice to Reopen Comment Period

  16. Degradation mechanisms of GaN high electron mobility transistors

    E-Print Network [OSTI]

    Joh, Jungwoo

    2007-01-01T23:59:59.000Z

    In spite of their extraordinary performance, GaN high electron mobility transistors (HEMT) have still limited reliability. In RF power applications, GaN HEMTs operate at high voltage where good reliability is essential. ...

  17. Microsoft PowerPoint - High Gradient Inverse Free Electron Laser...

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

    Hi h G di t Hi h i High Gradient High energy gain Inverse Free Electron Laser at BNL P. Musumeci UCLA Department of Physics and Astronomy ATF user meeting April 2-3 2009 Outline...

  18. High-intensity laser-driven proton acceleration enhancement from hydrogen containing ultrathin targets

    SciTech Connect (OSTI)

    Dollar, F.; Reed, S. A.; Matsuoka, T.; Bulanov, S. S.; Chvykov, V.; Kalintchenko, G.; McGuffey, C.; Rousseau, P.; Thomas, A. G. R.; Willingale, L.; Yanovsky, V.; Krushelnick, K.; Maksimchuk, A. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Litzenberg, D. W. [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2013-09-30T23:59:59.000Z

    Laser driven proton acceleration experiments from micron and submicron thick targets using high intensity (2 × 10{sup 21} W/cm{sup 2}), high contrast (10{sup ?15}) laser pulses show an enhancement of maximum energy when hydrogen containing targets were used instead of non-hydrogen containing. In our experiments, using thin (<1?m) plastic foil targets resulted in maximum proton energies that were consistently 20%–100% higher than when equivalent thickness inorganic targets, including Si{sub 3}N{sub 4} and Al, were used. Proton energies up to 20 MeV were measured with a flux of 10{sup 7} protons/MeV/sr.

  19. Beam extraction and high stability operation of high current electron cyclotron resonance proton ion source

    SciTech Connect (OSTI)

    Roychowdhury, P., E-mail: pradipr@barc.gov.in; Mishra, L.; Kewlani, H.; Mittal, K. C. [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)] [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Patil, D. S. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)] [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2014-03-15T23:59:59.000Z

    A high current electron cyclotron resonance proton ion source is designed and developed for the low energy high intensity proton accelerator at Bhabha Atomic Research Centre. The plasma discharge in the ion source is stabilized by minimizing the reflected microwave power using four stub auto tuner and magnetic field. The optimization of extraction geometry is performed using PBGUNS code by varying the aperture, shape, accelerating gap, and the potential on the electrodes. While operating the source, it was found that the two layered microwave window (6 mm quartz plate and 2 mm boron nitride plate) was damaged (a fine hole was drilled) by the back-streaming electrons after continuous operation of the source for 3 h at beam current of 20–40 mA. The microwave window was then shifted from the line of sight of the back-streaming electrons and located after the water-cooled H-plane bend. In this configuration the stable operation of the high current ion source for several hours is achieved. The ion beam is extracted from the source by biasing plasma electrode, puller electrode, and ground electrode to +10 to +50 kV, ?2 to ?4 kV, and 0 kV, respectively. The total ion beam current of 30–40 mA is recorded on Faraday cup at 40 keV of beam energy at 600–1000 W of microwave power, 800–1000 G axial magnetic field and (1.2–3.9) × 10{sup ?3} mbar of neutral hydrogen gas pressure in the plasma chamber. The dependence of beam current on extraction voltage, microwave power, and gas pressure is investigated in the range of operation of the ion source.

  20. Nonlinear interaction of intense electromagnetic waves with a magnetoactive electron-positron-ion plasma

    SciTech Connect (OSTI)

    Khorashadizadeh, S. M.; Rastbood, E.; Zeinaddini Meymand, H. [Physics Department, University of Birjand, Birjand (Iran, Islamic Republic of)] [Physics Department, University of Birjand, Birjand (Iran, Islamic Republic of); Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)] [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)

    2013-08-15T23:59:59.000Z

    The nonlinear coupling between circularly polarized electromagnetic (CPEM) waves and acoustic-like waves in a magnetoactive electron-positron-ion (e-p-i) plasma is studied, taking into account the relativistic motion of electrons and positrons. The possibility of modulational instability and its growth rate as well as the envelope soliton formation and its characteristics in such plasmas are investigated. It is found that the growth rate of modulation instability increases in the case that ?{sub c}/?<1 (?{sub c} and ? are the electron gyrofrequency and the CPEM wave frequency, respectively) and decreases in the case that ?{sub c}/?>1. It is also shown that in a magnetoactive e-p-i plasma, the width of bright soliton increases/decreases in case of (?{sub c}/?)<1/(?{sub c}/?)>1 by increasing the magnetic field strength.

  1. PHYSICAL REVIEW SPECIAL TOPICS -ACCELERATORS AND BEAMS, VOLUME 2, 121301 (1999) Temporary acceleration of electrons while inside an intense electromagnetic pulse

    E-Print Network [OSTI]

    McDonald, Kirk

    1999-01-01T23:59:59.000Z

    acceleration of electrons while inside an intense electromagnetic pulse Kirk T. McDonald Joseph Henry incident on a gas. Intense electromagnetic pulses of astrophysical origin can lead to very energetic" associated with the envelope of the electromagnetic pulse [3]. The resulting temporary energy transfer

  2. REVIEW OF SCIENTIFIC INSTRUMENTS 84, 022701 (2013) Intense terahertz pulses from SLAC electron beams using coherent

    E-Print Network [OSTI]

    2013-01-01T23:59:59.000Z

    February 2013) SLAC has two electron accelerators, the Linac Coherent Light Source (LCLS) and the Facility via coherent transition radiation. For LCLS and FACET respectively, the THz pulse duration field at a THz focus has reached 4.4 GV/m (0.44 V/Ĺ) at LCLS. This paper presents measurements

  3. Neutron Halo Isomers in Stable Nuclei and their Possible Application for the Production of Low Energy, Pulsed, Polarized Neutron Beams of High Intensity and High Brilliance

    E-Print Network [OSTI]

    D. Habs; M. Gross; P. G. Thirolf; P. Böni

    2010-09-30T23:59:59.000Z

    We propose to search for neutron halo isomers populated via $\\gamma$-capture in stable nuclei with mass numbers of about A=140-180 or A=40-60, where the $4s_{1/2}$ or $3s_{1/2}$ neutron shell model state reaches zero binding energy. These halo nuclei can be produced for the first time with new $\\gamma$-beams of high intensity and small band width ($\\le$ 0.1%) achievable via Compton back-scattering off brilliant electron beams thus offering a promising perspective to selectively populate these isomers with small separation energies of 1 eV to a few keV. Similar to single-neutron halo states for very light, extremely neutron-rich, radioactive nuclei \\cite{hansen95,tanihata96,aumann00}, the low neutron separation energy and short-range nuclear force allows the neutron to tunnel far out into free space much beyond the nuclear core radius. This results in prolonged half lives of the isomers for the $\\gamma$-decay back to the ground state in the 100 ps-$\\mu$s range. Similar to the treatment of photodisintegration of the deuteron, the neutron release from the neutron halo isomer via a second, low-energy, intense photon beam has a known much larger cross section with a typical energy threshold behavior. In the second step, the neutrons can be released as a low-energy, pulsed, polarized neutron beam of high intensity and high brilliance, possibly being much superior to presently existing beams from reactors or spallation neutron sources.

  4. Ultra-high-contrast laser acceleration of relativistic electrons in solid targets

    E-Print Network [OSTI]

    Higginson, Drew Pitney

    2013-01-01T23:59:59.000Z

    Intensities with Short-Pulse Lasers 1.2 Inertial Confinementhigh-power, short laser pulse, D. . . . . . . . . . Figurea high-intensity short-pulse laser to produce relativistic

  5. First high-temperature electronics products survey 2005.

    SciTech Connect (OSTI)

    Normann, Randy Allen

    2006-04-01T23:59:59.000Z

    On April 4-5, 2005, a High-Temperature Electronics Products Workshop was held. This workshop engaged a number of governmental and private industry organizations sharing a common interest in the development of commercially available, high-temperature electronics. One of the outcomes of this meeting was an agreement to conduct an industry survey of high-temperature applications. This report covers the basic results of this survey.

  6. The slingshot effect: a possible new laser-driven high energy acceleration mechanism for electrons

    E-Print Network [OSTI]

    Gaetano Fiore; Renato Fedele; Umberto de Angelis

    2014-11-14T23:59:59.000Z

    We show that under appropriate conditions the impact of a very short and intense laser pulse onto a plasma causes the expulsion of surface electrons with high energy in the direction opposite to the one of propagation of the pulse. This is due to the combined effects of the ponderomotive force and the huge longitudinal field arising from charge separation ("slingshot effect"). The effect should also be present with other states of matter, provided the pulse is sufficiently intense to locally cause complete ionization. An experimental test seems to be feasible and, if confirmed, would provide a new extraction and acceleration mechanism for electrons, alternative to traditional radio-frequency-based or Laser-Wake-Field ones.

  7. Measurement of intensities of bands in the electronic absorption spectrum of chlorine dioxide

    E-Print Network [OSTI]

    Rapp, Thomas Louis

    1955-01-01T23:59:59.000Z

    energy levels are derived, Twelve bands in the electronic absorption spectrum of chlorine dioxide between the wavelengths 4250 R and 5250 R were photographed and measured. Of these twelve, the vibrational energy levels calculated for nine of them... Calculation of Vibrational Energy Levels . . . . , 35 Estimation of Errors . . . , . . . . . . . . . . . 38 CONCLUSIONS Conolusions ~ ~ ~ 47 B IBLI QGRAFEZ ~ ~ ~ ~ ~ ~ ~ ~ 48 ~INTRGDUGT10 Analysis of thc rotational structure of the chlorine dioxide...

  8. A Tale of Two Electrons: Correlation at High Density

    E-Print Network [OSTI]

    Loos, Pierre-François

    2010-01-01T23:59:59.000Z

    We review our recent progress in the determination of the high-density correlation energy $\\Ec$ in two-electron systems. Several two-electron systems are considered, such as the well known helium-like ions (helium), and the Hooke's law atom (hookium). We also present results regarding two electrons on the surface of a sphere (spherium), and two electrons trapped in a spherical box (ballium). We also show that, in the large-dimension limit, the high-density correlation energy of two opposite-spin electrons interacting {\\em via} a Coulomb potential is given by $\\Ec \\sim -1/(8D^2)$ for any radial external potential $V(r)$, where $D$ is the dimensionality of the space. This result explains the similarity of $\\Ec$ in the previous two-electron systems for $D=3$.

  9. Microwave power spectral density and its effects on exciting electrodeless high intensity discharge lamps

    SciTech Connect (OSTI)

    Butler, S.J.; Goss, H.H.; Lapatovich, W.P. [Osram Sylvania Inc., Salem, MA (United States)

    1995-12-31T23:59:59.000Z

    The effects of a microwave source generating a spectrally dense power spectrum on the operation of an electrodeless high intensity discharge lamp were measured. Spectrally pure sources operating within ISM bands at 915 MHz and 2.45 GHz produce stable capacitively coupled discharges useful for producing flicker-free light for numerous applications. The internal plasma temperature distribution and lamp geometry define acoustic resonance modes within the lamp which can be excited with power sidebands. The operation of lamps with commercially available power sources and custom built generators are discussed. Estimates of the spectral purity required for stable operation are provided.

  10. Production of neutrons up to 18 MeV in high-intensity, short-pulse laser matter interactions

    E-Print Network [OSTI]

    Production of neutrons up to 18 MeV in high-intensity, short-pulse laser matter interactions D. P of neutrons up to 18 MeV in high-intensity, short-pulse laser matter interactions D. P. Higginson,1,2 J. M. Mc of laser energy in a 9 ps pulse. In this technique, a short-pulse, high-energy laser accelerates deuterons

  11. High-pressure synthesis of electronic materials 

    E-Print Network [OSTI]

    Penny, George B. S.

    2010-01-01T23:59:59.000Z

    High-pressure techniques have become increasingly important in the synthesis of ceramic and metallic solids allowing the discovery of new materials with interesting properties. In this research dense solid oxides have ...

  12. Proposal for a High-Brightness Pulsed Electron Source

    SciTech Connect (OSTI)

    Zolotorev, Max; Commins, Eugene D.; Heifets, Sam; Sannibale,Fernando

    2006-03-15T23:59:59.000Z

    We propose a novel scheme for a high-brightness pulsedelectron source, which has the potential for many useful applications inelectron microscopy, inverse photo-emission, low energy electronscattering experiments, and electron holography. A description of theproposed scheme is presented.

  13. Reflection High-Energy Electron Diffraction Beam-Induced Structural...

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

    Beam-Induced Structural and Property Changes on WO3 Thin Films. Reflection High-Energy Electron Diffraction Beam-Induced Structural and Property Changes on WO3 Thin...

  14. Vacuum ultra-violet emission of plasma discharges with high Xe partial pressure using a cathode protective layer with high secondary electron emission

    SciTech Connect (OSTI)

    Zhu, Di [School of Electronics and Information Engineering, Tianjin Polytechnic University, Tianjin (China); Song, Le, E-mail: songle@tju.edu.cn [State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin (China); Zhang, Xiong [School of Electronic Science and Engineering, Southeast University, Nanjing (China); Kajiyama, Hiroshi [Graduate School of Advanced Science of Matter, Hiroshima University, Higashi-hiroshima, Hiroshima (Japan)

    2014-02-14T23:59:59.000Z

    In this work, the mechanism of the vacuum ultra-violet (VUV) emission of plasma discharges, with high Xe partial pressure and high ion-induced secondary electrons emission protective layer, is studied by measuring the VUV light emission directly and comparing it with two-dimensional simulations. From the panel measurement, we find that the high intensity of excimer VUV mainly contributes to the high luminous efficacy of SrCaO-plasma display panels (PDP) at a low sustain voltage. The unchanged Xe excitation efficiency indicates that the electron temperature is not decreased by the high secondary electrons emission protective layer, even though the sustain voltage is much lower. From the two-dimensional simulations, we can find that the ratio of excimer VUV to resonant VUV, which is determined by the collision rate in the discharge, is only significantly affected by the Xe partial pressure, while it is independent of the sustain voltage and the secondary-electrons-emission capability of protective layer. The unchanged average electron energy at the moment when the electric field becomes maximum confirms that the improvement of the VUV production efficiency mainly is attributed to the increase in electron heating efficiency of a PDP with high ion-induced secondary electrons emission protective layer. Combining the experimental and the simulation results, we conclude about the mechanism by which the VUV production is improved for the plasma display panel with a high Xe partial pressure and a cold cathode with high ion-induced secondary electrons emission.

  15. 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}.

  16. System and method that suppresses intensity fluctuations for free space high-speed optical communication

    DOE Patents [OSTI]

    Berman, Gennady P. (Los Alamos, NM); Bishop, Alan R. (Los Alamos, NM); Nguyen, Dinh C. (Los Alamos, NM); Chernobrod, Boris M. (Santa Fe, NM); Gorshkov, Vacheslav N. (Kiev, UA)

    2009-10-13T23:59:59.000Z

    A high-speed (Gbps), free space optical communication system is based on spectral encoding of radiation from a wide band light source, such as a laser. By using partially coherent laser beams in combination with a relatively slow photosensor, scintillations can be suppressed by orders of magnitude for distances of more than 10 km. To suppress the intensity fluctuations due to atmospheric turbulence, a source with partial transverse coherence in combination with slow response time photodetector is used. Information is encoded in the spectral domain of a wideband optical source by modulation of spectral amplitudes. A non-coherent light source with wide spectrum (an LED, for example) may be used for high-speed communication over short (less than about a mile) distances.

  17. High power 325 MHz vector modulators for the Fermilab High Intensity Neutrino Source (HINS)

    SciTech Connect (OSTI)

    Madrak, Robyn Leigh; Wildman, David; /Fermilab

    2008-10-01T23:59:59.000Z

    One of the goals of the low energy 60 MeV section of the HINS H{sup -} linac [1] is to demonstrate that a total of {approx}40 RF cavities can be powered by a single 2.5 MW, 325 MHz klystron. This requires individual vector modulators at the input of each RF cavity to independently adjust the amplitude and phase of the RF input signal during the 3.5 ms RF pulse. Two versions of vector modulators have been developed; a 500 kW device for the radiofrequency quadrupole (RFQ) and a 75 kW modulator for the RF cavities. High power tests showing the vector modulator phase and amplitude responses will be presented.

  18. Millimeter-wave GaN high electron mobility transistors and their integration with silicon electronics

    E-Print Network [OSTI]

    Chung, Jinwook W. (Jinwook Will)

    2011-01-01T23:59:59.000Z

    In spite of the great progress in performance achieved during the last few years, GaN high electron mobility transistors (HEMTs) still have several important issues to be solved for millimeter-wave (30 ~ 300 GHz) applications. ...

  19. On the GCR intensity and the inversion of the heliospheric magnetic field during the periods of the high solar activity

    E-Print Network [OSTI]

    Krainev, M B

    2014-01-01T23:59:59.000Z

    We consider the long-term behavior of the solar and heliospheric parameters and the GCR intensity in the periods of high solar activity and the inversions of heliospheric magnetic field (HMF). The classification of the HMF polarity structures and the meaning of the HMF inversion are discussed. The procedure is considered how to use the known HMF polarity distribution for the GCR intensity modeling during the periods of high solar activity. We also briefly discuss the development and the nearest future of the sunspot activity and the GCR intensity in the current unusual solar cycle 24.

  20. Measurements of high energy density electrons via observation of Cherenkov radiation

    SciTech Connect (OSTI)

    Habara, Hideaki; Ohta, Kazuhide; Tanaka, Kazuo A. [Graduate School of Engineering, Osaka University, 2-1, Yamada-oka, Suita, Osaka 565-0871, Japan and Laser Institute of Engineering, Osaka University, 2-6, Yamada-oka, Suita, Osaka 565-0871 (Japan); Kumar, G. Ravindra; Krishnamurthy, M.; Kahaly, Subhendu; Mondal, Sudipta; Bhuyan, Manoj Kumar; Rajeev, R. [Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400-005 (India); Zheng Jian [Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2010-05-15T23:59:59.000Z

    Direct measurement of extremely high energy density electrons created in ultraintense laser-plasma interactions is crucial issue for fast ignition. Recently Cherenkov radiation has been studied to obtain the energy distribution of electrons because the emission angle depends on the electron energy. However in the previous studies [F. Brandl et al., Europhys. Lett. 61, 632 (2003); M. Manclossi et al., Phys. Rev. Lett. 96, 125002 (2006)], the experimental configurations using a planar target raised issues of spatial overlapping among the light from the different energy electrons as well as from the other emissions, such as transition radiation. A novel prism shaped target is developed in which Cherenkov lights emitted from different energy electrons are spatially separated, realizing an absolute measurement of the energy spectrum by counting the light intensities in each observed position. The observed image clearly shows the horseshoe pattern as expected in fully three-dimensional ray-trace calculations, and the image is successfully converted into the electron spectrum inside the target. In addition, it is found from the blur of the outer edge of the Cherenkov pattern that the electrons have a small beam divergence. The calibrated energy spectrum well agrees with particle simulations.

  1. Fast Frontend Electronics for high luminosity particle detectors

    E-Print Network [OSTI]

    Cardinali, M; Bondy, M I Ferretti; Hoek, M; Lauth, W; Rosner, C; Sfienti, C; Thiel, M

    2015-01-01T23:59:59.000Z

    Future experiments of nuclear and particle physics are moving towards the high luminosity regime, in order to access suppressed processes like rare B decays or exotic charmonium resonances. In this scenario, high rate capability is a key requirement for electronics instrumentation, together with excellent timing resolution for precise event reconstruction. The development of dedicated FrontEnd Electronics (FEE) for detectors has become increasingly challenging. A current trend in R&D is towards multipurpose FEE which can be easily adapted to a great variety of detectors, without impairing the required high performance. We report on high-precision timing solutions which utilise high-bandwidth preamplifiers and fast discriminators providing Time-over-Threshold information, which can be used for charge measurements or walk corrections thus improving the obtainable timing resolution. The output signal are LVDS and can be directly fed into a multi-hit TDC readout. The performance of the electronics was investi...

  2. Relativistic effects in the interaction of high intensity ultra-short laser pulse with collisional underdense plasma

    SciTech Connect (OSTI)

    Abedi, Samira [Physics Department, North Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Dorranian, Davoud [Laser Lab., Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Abari, Mehdi Etehadi [Physics Department, Science Faculty, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Shokri, Babak [Physics Department, Science Faculty, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of); Laser-Plasma Research Institute, Shahid Beheshti University, G.C., Evin, Tehran 19839 (Iran, Islamic Republic of)

    2011-09-15T23:59:59.000Z

    In this paper, the effect of weakly relativistic ponderomotive force in the interaction of intense laser pulse with nonisothermal, underdense, collisional plasma is studied. Ponderomotive force modifies the electron density and temperature distribution. By considering the weakly relativistic effect and ohmic heating of plasma electrons, the nonlinear dielectric permittivity of plasma medium is obtained and the equation of electromagnetic wave propagation in plasma is solved. It is shown that with considering the ohmic heating of electrons and collisions, the effect of ponderomotive force in weakly relativistic regime leads to steepening the electron density profile and increases the temperature of plasma electrons noticeably. Bunches of electrons in plasma become narrower. By increasing the laser pulse strength, the wavelength of density oscillations decreases. In this regime of laser-plasma interaction, electron temperature increases sharply by increasing the intensity of laser pulse. The amplitude of electric and magnetic fields increases by increasing the laser pulse energy while their wavelength decreases and they lost their sinusoidal form.

  3. Epithermal Neutron Source for Neutron Resonance Spectroscopy (NRS) using High Intensity, Short Pulse Lasers

    SciTech Connect (OSTI)

    Higginson, D P; McNaney, J M; Swift, D C; Bartal, T; Hey, D S; Pape, S L; Mackinnon, A; Mariscal, D; Nakamura, H; Nakanii, N; Beg, F N

    2010-04-22T23:59:59.000Z

    A neutron source for neutron resonance spectroscopy (NRS) has been developed using high intensity, short pulse lasers. This measurement technique will allow for robust measurements of interior ion temperature of laser-shocked materials and provide insight into equation of state (EOS) measurements. The neutron generation technique uses protons accelerated by lasers off of Cu foils to create neutrons in LiF, through (p,n) reactions with {sup 7}Li and {sup 19}F. The distribution of the incident proton beam has been diagnosed using radiochromic film (RCF). This distribution is used as the input for a (p,n) neturon prediction code which is compared to experimentally measured neutron yields. From this calculation, a total fluence of 1.8 x 10{sup 9} neutrons is infered, which is shown to be a reasonable amount for NRS temperature measurement.

  4. MR-Guided High-Intensity Focused Ultrasound: Current Status of an Emerging Technology

    SciTech Connect (OSTI)

    Napoli, Alessandro, E-mail: napoli.alessandro@gmail.com; Anzidei, Michele, E-mail: michele.anzidei@gmail.com; Ciolina, Federica, E-mail: federica.ciolina@gmail.com; Marotta, Eugenio, E-mail: eugenio.marotta@gmail.com; Cavallo Marincola, Beatrice, E-mail: beatrice.cavalloamarincola@gmail.com; Brachetti, Giulia, E-mail: giuliabrachetti@gmail.com; Mare, Luisa Di, E-mail: luisadimare@gmail.com; Cartocci, Gaia, E-mail: gaia.cartocci@gmail.com; Boni, Fabrizio, E-mail: fabrizioboni00@gmail.com; Noce, Vincenzo, E-mail: vinc.noce@hotmail.it; Bertaccini, Luca, E-mail: lucaone84@libero.it; Catalano, Carlo, E-mail: carlo.catalano@uniroma1.it [Sapienza, University of Rome, Department of Radiological Sciences (Italy)] [Sapienza, University of Rome, Department of Radiological Sciences (Italy)

    2013-10-15T23:59:59.000Z

    The concept of ideal tumor surgery is to remove the neoplastic tissue without damaging adjacent normal structures. High-intensity focused ultrasound (HIFU) was developed in the 1940s as a viable thermal tissue ablation approach. In clinical practice, HIFU has been applied to treat a variety of solid benign and malignant lesions, including pancreas, liver, prostate, and breast carcinomas, soft tissue sarcomas, and uterine fibroids. More recently, magnetic resonance guidance has been applied for treatment monitoring during focused ultrasound procedures (magnetic resonance-guided focused ultrasound, MRgFUS). Intraoperative magnetic resonance imaging provides the best possible tumor extension and dynamic control of energy deposition using real-time magnetic resonance imaging thermometry. We introduce the fundamental principles and clinical indications of the MRgFUS technique; we also report different treatment options and personal outcomes.

  5. Industrial Fabrication of Medium-Beta SCRF Cavities for a High-Intensity Proton Linac

    E-Print Network [OSTI]

    Kuzminski, J; Gentzlinger, R C; Maccioni, P

    2000-01-01T23:59:59.000Z

    During 1999, four 700-MHz, medium-beta (b = 0.64), superconducting radio frequency (SCRF) cavities for a high-intensity proton linac project at Los Alamos National Laboratory (LANL) were manufactured by industry. The SCRF cavities were designed by a LANL team in Los Alamos, New Mexico, USA, and manufactured at a CERCA plant in Romans, France. The cavities were made of 4-mm-thick, solid niobium sheets with a residual resistivity ratio (RRR) greater than 250. These niobium sheets were supplied by Wah Chang (USA), Heraeus AG (Germany), and Tokyo Denkai (Japan). The SCRF cavities were shipped to LANL for performance testing. This paper describes the experience gained during the manufacturing process at CERCA.

  6. Left-Right Symmetric Models at the High-Intensity Frontier

    E-Print Network [OSTI]

    Castillo-Felisola, Oscar; Helo, Juan C; Kovalenko, Sergey G; Ortiz, Sebastian E

    2015-01-01T23:59:59.000Z

    We study constraints on Left-Right Symmetric models from searches of semileptonic decays of $D$, $D_{s}$, $B$ mesons, mediated by heavy neutrinos $N$ with masses $m_N\\sim $ GeV that go on their mass shell leading to a resonant enhancement of the rates. Using these processes we examine, as a function of $m_N$ and $M_{W_R}$, the physics reach of the recently proposed high-intensity beam dump experiment SHiP, which is expected to produce a large sample of $D_s$ mesons. We compare these results with the corresponding reach of neutrinoless double beta decay experiments, as well as like-sign dilepton searches with displaced vertices at the LHC. We conclude that the SHiP experiment has clear advantages in probing the Left-Right Symmetric models for heavy neutrinos in the GeV mass range.

  7. Diamondoid monolayers as electron emitters

    DOE Patents [OSTI]

    Yang, Wanli (El Cerrito, CA); Fabbri, Jason D. (San Francisco, CA); Melosh, Nicholas A. (Menlo Park, CA); Hussain, Zahid (Orinda, CA); Shen, Zhi-Xun (Stanford, CA)

    2012-04-10T23:59:59.000Z

    Provided are electron emitters based upon diamondoid monolayers, preferably self-assembled higher diamondoid monolayers. High intensity electron emission has been demonstrated employing such diamondoid monolayers, particularly when the monolayers are comprised of higher diamondoids. The application of such diamondoid monolayers can alter the band structure of substrates, as well as emit monochromatic electrons, and the high intensity electron emissions can also greatly improve the efficiency of field-effect electron emitters as applied to industrial and commercial applications.

  8. Diamondoid monolayers as electron emitters

    DOE Patents [OSTI]

    Yang, Wanli; Fabbri, Jason D.; Melosh, Nicholas A.; Hussain, Zahid; Shen, Zhi-Xun

    2013-10-29T23:59:59.000Z

    Provided are electron emitters based upon diamondoid monolayers, preferably self-assembled higher diamondoid monolayers. High intensity electron emission has been demonstrated employing such diamondoid monolayers, particularly when the monolayers are comprised of higher diamondoids. The application of such diamondoid monolayers can alter the band structure of substrates, as well as emit monochromatic electrons, and the high intensity electron emissions can also greatly improve the efficiency of field-effect electron emitters as applied to industrial and commercial applications.

  9. Meson production in high-energy electron-nucleus scattering

    E-Print Network [OSTI]

    Göran Fäldt

    2010-06-09T23:59:59.000Z

    Experimental studies of meson production through two-photon fusion in inelastic electron-nucleus scattering is now under way. A high-energy photon radiated by the incident electron is fused with a soft photon radiated by the nucleus. The process takes place in the small-angle-Coulomb region of nuclear scattering. We expound the theory for this production process as well as its interference with coherent-radiative-meson production. In particular, we investigate the distortion of the electron wave function due to multiple-Coulomb scattering.

  10. High voltage power supply systems for electron beam and plasma technologies. Its new element base

    SciTech Connect (OSTI)

    Dermengi, P.G.; Kureghan, A.S.; Pokrovsky, S.V.; Tchvanov, V.A.

    1994-12-31T23:59:59.000Z

    Transforming technique and high voltage technique supplementing each other more and more unite in indivisible constructions of modern apparatuses and systems and applicated in modern technologies providing its high efficiency. Specially worked out, ecologically clean, inertial, inflammable perfluororganic liquid is used in elements and electronic apparatuses simultaneously as insulating and cooling media. This liquid is highly fluid, fills tiny cavities in construction elements and in the places of high concentration of losses, where maximum local overheating of active parts or apparatus constructions takes place, it transforms to boiling state with highly intensive taking off of heat energy from cooled surface point. For instance, being cooled by mentioned perfluororganic liquid, copper wire can conduct current to 50 A/mm{sup 2} density, but in ordinary conditions of transformers, reactors and busses, current density can reach only few Amperes. Possibility of considerable increasing of current density, that is reached by means of intensive cooling, provided by worked out liquid, and taking into account its incredibly high insulating features (liquid has electric strength to 50 KV/mm) allows to provide optimum heat regime of active parts of transformers. reactors, condenser, semiconductor devices, resistors, construction elements and electrotechnical apparatus in general. Particularly high effect of decreasing of weight and dimensions characteristics of elements and electrotechnical apparatus in general can be reached under working out of special constructions of each element and apparatus details, adapted to use of mentioned liquid as insulating and cooling media.

  11. Terahertz plasma wave resonance of two-dimensional electrons in InGaP/InGaAs/GaAs high-electron-mobility transistors

    SciTech Connect (OSTI)

    Otsuji, Taiichi; Hanabe, Mitsuhiro; Ogawara, Osamu [Kyushu Institute of Technology, Graduate School of Computer Science and Systems Engineering, 680-4 Kawazu, Iizuka, Fukuoka, 820-8502 (Japan)

    2004-09-13T23:59:59.000Z

    We have observed the frequency dependence of the plasma resonant intensity in the terahertz range for a short gate-length InGaP/InGaAs/GaAs pseudomorphic high-electron-mobility transistor. The plasma resonance excitation was performed by means of interband photoexcitation using the difference-frequency component of a photomixed laser beam. Under sufficient density of two-dimensional (2D) conduction electrons (>10{sup 12} cm{sup -2}) and a moderate modulation index (the ratio of the density of photoexcited electrons to the initial density of the 2D electrons) we clearly observed the plasma-resonant peaks at 1.9 and 5.8 THz corresponding to the fundamental and third-harmonic resonance at room temperature, which is in good agreement with theory.

  12. Head-on beam-beam collisions with high intensities and long range beam-beam studies in the LHC

    E-Print Network [OSTI]

    Albert, M; Assmann, R; Buffat, X; Calaga, R; Cornelis, K; Fitterer, M; Giachino, R; Herr, W; Miyamoto, R; Norman, L; Papotti, G; Pieloni, T; Ponce, L; Redaelli, S; Schaumann, M; Trad, G; Wollmann, D

    2011-01-01T23:59:59.000Z

    In two experiments we studied possible limitations due to the beam-beam effects in the LHC. In the first experiment we collided high intensity bunches head-on to explore the region for high luminosity collisions. In the second test we reduced the crossing angle in the presence of long range encounters to increase their effects.

  13. Performance of a new electron-tracking Compton camera under intense radiations from a water target irradiated with a proton beam

    E-Print Network [OSTI]

    Yoshihiro Matsuoka; T. Tanimori; H. Kubo; A. Takada; J. D. Parker; T. Mizumoto; Y. Mizumura; S. Iwaki; T. Sawano; S. Komura; T. Kishimoto; M. Oda; T. Takemura; S. Miyamoto; S. Sonoda; D. Tomono; K. Miuchi; S. Kabuki; S. Kurosawa

    2015-01-22T23:59:59.000Z

    We have developed an electron-tracking Compton camera (ETCC) for use in next-generation MeV gamma ray telescopes. An ETCC consists of a gaseous time projection chamber (TPC) and pixel scintillator arrays (PSAs). Since the TPC measures the three dimensional tracks of Compton-recoil electrons, the ETCC can completely reconstruct the incident gamma rays. Moreover, the ETCC demonstrates efficient background rejection power in Compton-kinematics tests, identifies particle from the energy deposit rate (dE/dX) registered in the TPC, and provides high quality imaging by completely reconstructing the Compton scattering process. We are planning the "Sub-MeV gamma ray Imaging Loaded-on-balloon Experiment" (SMILE) for our proposed all-sky survey satellite. Performance tests of a mid-sized 30 cm-cubic ETCC, constructed for observing the Crab nebula, are ongoing. However, observations at balloon altitudes or satellite orbits are obstructed by radiation background from the atmosphere and the detector itself. The background rejection power was checked using proton accelerator experiments conducted at the Research Center for Nuclear Physics, Osaka University. To create the intense radiation fields encountered in space, which comprise gamma rays, neutrons, protons, and other energetic entities, we irradiated a water target with a 140 MeV proton beam and placed a SMILE-II ETCC near the target. In this situation, the counting rate was five times than that expected at the balloon altitude. Nonetheless, the ETCC stably operated and identified particles sufficiently to obtain a clear gamma ray image of the checking source. Here, we report the performance of our detector and demonstrate its effective background rejection based in electron tracking experiments.

  14. Ultrafast electron cascades in semiconductors driven by intense femtosecond terahertz pulses H. Wen,1 M. Wiczer,3 and A. M. Lindenberg1,2

    E-Print Network [OSTI]

    Ultrafast electron cascades in semiconductors driven by intense femtosecond terahertz pulses H. Wen processing. With wavelengths in the far infrared, near­ half-cycle THz pulses can be thought of as ultrafast,1 M. Wiczer,3 and A. M. Lindenberg1,2 1PULSE Institute, Stanford Linear Accelerator Center, Menlo

  15. Ultra-low noise high electron mobility transistors for high-impedance and low-frequency deep cryogenic readout electronics

    SciTech Connect (OSTI)

    Dong, Q.; Liang, Y. X.; Ferry, D.; Cavanna, A.; Gennser, U.; Couraud, L.; Jin, Y., E-mail: yong.jin@LPN.cnrs.fr [CNRS, Laboratoire de Photonique et de Nanostructures (LPN), Route de Nozay, 91460 Marcoussis (France)

    2014-07-07T23:59:59.000Z

    We report on the results obtained from specially designed high electron mobility transistors at 4.2?K: the gate leakage current can be limited lower than 1 aA, and the equivalent input noise-voltage and noise-current at 1?Hz can reach 6.3 nV/Hz{sup 1?2} and 20 aA/Hz{sup 1?2}, respectively. These results open the way to realize high performance low-frequency readout electronics under very low-temperature conditions.

  16. Electron Probe Micro-Analysis Nilanjan Chatterjee, Ph.D.

    E-Print Network [OSTI]

    Rothman, Daniel

    -scattered electron (BSE) (Elastic scattering) Beam electrons scattered backward from specimen surface High energy Emitted at low energies (typical: high energy beam electrons that underwent) #12;Cathodoluminescence spectrometry CL spectrum Energy Intensity #12;Understanding X

  17. Electronically conductive ceramics for high temperature oxidizing environments

    DOE Patents [OSTI]

    Kucera, G.H.; Smith, J.L.; Sim, J.W.

    1983-11-10T23:59:59.000Z

    This invention pertains to a high temperature, ceramic composition having electronic conductivity as measured by resistivity below about 500 ohm-cm, chemical stability particularly with respect to cathode conditions in a molten carbonate fuel cell, and composed of an alkali metal, transition metal oxide containing a dopant metal in the crystalline structure to replace a portion of the alkali metal or transition metal.

  18. Exact and variational solutions of 3D Eigenmodes in high gain Free Electron Lasers

    E-Print Network [OSTI]

    Xie, M.

    2011-01-01T23:59:59.000Z

    Motz, Undulators and Free-Electron Lasers, (Clarendon Press,in High . Gain Free Electron Lasers MingXie Accelerator andin High Gain Free Electron Lasers Ming Xie Accelerator and

  19. OPTIMIZATION OF THE PARAMETERS OF A STORAGE RING FOR A HIGH POWER XUV FREE ELECTRON LASER

    E-Print Network [OSTI]

    Jackson, A.

    2010-01-01T23:59:59.000Z

    A.M. Sessler. 'free Electron Laser . LBL -l 8905 (JanuaryFOR A HIGH POWER XUV FREE ELECTRON LASER. A. Jackson, J.for a High Power XUV Free Electron Laser," (LBL'19771, June,

  20. The botanical composition of cattle diets on a 7-pasture high-intensity low-frequency grazing system

    E-Print Network [OSTI]

    Taylor, Charles Andrew

    1973-01-01T23:59:59.000Z

    THE BOTANICAL COMPOSITION OF CATTLE DIETS ON A 7-PASTURE HIGH-INTENSITY LOW-FREQUENCY GRAZING SYSTEM A Thesis by CHARLES ANDREW TAYLOR, JR. Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE May, 1973 MaJor SubJect: Range Science THE BOTANICAL COYiPOSITION OF CATTLE DIETS ON A 7-PASTI|RE HIGH-INTENSITY LOW-FREQUENCY GRAZING SYSTFM A Thesis by CHARLES ANDREW TAYLOR, JR. Approved as to style and content by...

  1. Dimensional scaling treatment with relativistic corrections for stable multiply charged atomic ions in high-frequency super-intense laser fields

    E-Print Network [OSTI]

    Kais, Sabre

    in high-frequency super-intense laser fields Ross D. Hoehn, Jiaxiang Wang, and Sabre Kais Citation-intense laser fields Ross D. Hoehn,1 Jiaxiang Wang,2 and Sabre Kais1,a) 1 Departments of Chemistry and Physics

  2. TiN coated aluminum electrodes for DC high voltage electron guns

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

    Mamun, Md Abdullah A.; Elmustafa, Abdelmageed A.; Taus, Rhys; Forman, Eric; Poelker, Matthew

    2015-05-01T23:59:59.000Z

    Preparing electrodes made of metals like stainless steel, for use inside DC high voltage electron guns, is a labor-intensive and time-consuming process. In this paper, the authors report the exceptional high voltage performance of aluminum electrodes coated with hard titanium nitride (TiN). The aluminum electrodes were comparatively easy to manufacture and required only hours of mechanical polishing using silicon carbide paper, prior to coating with TiN by a commercial vendor. The high voltage performance of three TiN-coated aluminum electrodes, before and after gas conditioning with helium, was compared to that of bare aluminum electrodes, and electrodes manufactured from titanium alloymore »(Ti-6Al-4V). Following gas conditioning, each TiN-coated aluminum electrode reached ?225?kV bias voltage while generating less than 100?pA of field emission (« less

  3. High-Power Microwave Switch Employing Electron Beam Triggering

    SciTech Connect (OSTI)

    Jay L. Hirshfield

    2012-09-19T23:59:59.000Z

    A high-power active microwave pulse compressor is described that modulates the quality factor Q of the energy storage cavity by a new means involving mode conversion controlled by a triggered electron-beam discharge through a switch cavity. The electron beam is emitted from a diamond-coated molybdenum cathode. This report describes the principle of operation, the design of the switch, the configuration used for the test, and the experimental results. The pulse compressor produced output pulses with 140 - Ă?Â?165 MW peak power, power gain of 16 - 20, and pulse duration of 16 - 20 ns at a frequency of 11.43 GHz.

  4. Sourcebook on high-temperature electronics and instrumentation

    SciTech Connect (OSTI)

    Veneruso, A.F. (ed.)

    1981-10-01T23:59:59.000Z

    This sourcebook summarizes the high-temperature characteristics of a number of commercially available electronic components and materials required in geothermal well-logging instruments that must operate to 275/sup 0/C. The sourcebook is written to provide a starting place for instrument designers, who need to know the high-temperature electronic products that are available and the design and performance limitations of these products. The electronic component information given includes the standard repertoire of passive devices such as resistors, capacitors, and magnetics; the active devices and integrated circuits sections emphasize silicon semiconductor JFETs and CMOS circuits; and, to complete the electronics, interconnections and packaging of hybrid microelectronics are described. Thermal insulation and refrigeration alternatives are also presented in the sourcebook. Finally, instrument housing materials and high-temperature cables and cablehead connectors are listed. This information was compiled as part of the Geothermal Logging Instrumentation Development Program that Sandia National Laboratories conducted for the US Department of Energy's Divison of Geothermal Energy from 1976 to 1981.

  5. New developments for high power electron beam equipment

    SciTech Connect (OSTI)

    Melde, C.; Jaesch, G.; Maedler, E. [Von Ardenne Anlagentechnnik GmbH, Dresden (Germany)

    1994-12-31T23:59:59.000Z

    High power electron guns for industrial use work in the range of power of more than 10 kW up to 1200 kW. The only suitable principle for this purpose is that used in axial guns. Elements necessary for these EB guns and their design are described. The outstanding properties required for applications in production and R & D can only be achieved if the equipment is supplemented by a high voltage supply, beam guidance supply, vacuum generator and the various devices for observation, measurement and control. Standard rules for both the technical demands in application and dimensioning of some of the necessary components are explained. Special developments, such as high speed deflection, observation by BSE-camera and arc-free electron beam systems are also presented.

  6. Numerical Investigation of Symmetry Breaking and Critical Behavior of the Acoustic Streaming Field in High-Intensity Discharge Lamps

    E-Print Network [OSTI]

    Baumann, Bernd; Wolff, Marcus; Manders, Freddy; Suijker, Jos

    2014-01-01T23:59:59.000Z

    For energy efficiency and material cost reduction it is preferred to drive high-intensity discharge lamps at frequencies of approximately 300 kHz. However, operating lamps at these high frequencies bears the risk of stimulating acoustic resonances inside the arc tube, which can result in low frequency light flicker and even lamp destruction. The acoustic streaming effect has been identified as the link between high frequency resonances and low frequency flicker. A highly coupled 3D multiphysics model has been set up to calculate the acoustic streaming velocity field inside the arc tube of high-intensity discharge lamps. It has been found that the velocity field suffers a phase transition to an asymmetrical state at a critical acoustic streaming force. The system behaves similar to a ferromagnet near the Curie point. Furthermore, it is discussed how the model allows to investigate the light flicker phenomenon. Concerning computer resources the procedure is considerably less demanding than a direct approach wit...

  7. A high frequency polarization intensity electrooptic modulator in BSTN ferroelectric crystal

    E-Print Network [OSTI]

    Wilson, Erik James

    1996-01-01T23:59:59.000Z

    of 78% have been realized. Optical intensity modulation up to 1.5 GHz has been observed, and a 3-dB frequency value of 1.28 GHz has been achieved....

  8. Measured hot-electron intensity thresholds quantified by a two-plasmon-decay resonant common-wave gain in various experimental configurations

    SciTech Connect (OSTI)

    Michel, D. T.; Maximov, A. V.; Short, R. W.; Delettrez, J. A.; Edgell, D.; Hu, S. X.; Igumenshchev, I. V.; Myatt, J. F.; Solodov, A. A.; Stoeckl, C.; Yaakobi, B.; Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636 (United States)] [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14636 (United States)

    2013-05-15T23:59:59.000Z

    The fraction of laser energy converted into hot electrons by the two-plasmon-decay instability is found to have different overlapped intensity thresholds for various configurations on the Omega Laser Facility [T. R. Boehly et al., Opt. Commun. 133, 495 (1997); J. H. Kelly et al., J. Phys. IV 133, 75 (2006)]. A factor-of-2 difference in the overlapped intensity threshold is observed between two- and four-beam configurations. The overlapped intensity threshold increases by a factor of 2 between the 4- and 18-beam configurations and by a factor of 3 between the 4- and 60-beam configurations. This is explained by a linear common-wave model where multiple laser beams drive a common electron-plasma wave in a wavevector region that bisects the laser beams (resonant common-wave region in k-space). These experimental results indicate that the hot-electron threshold depends on the hydrodynamic parameters at the quarter-critical density surface, the configuration of the laser beams, and the sum of the intensity of the beams that share the same angle with the common-wave vector.

  9. Coherent and incoherent radiation from high-energy electron and the LPM effect in oriented single crystal

    E-Print Network [OSTI]

    V. N. Baier; V. M. Katkov

    2005-12-01T23:59:59.000Z

    The process of radiation from high-energy electron in oriented single crystal is considered using the method which permits inseparable consideration of both coherent and incoherent mechanisms of photon emission. The total intensity of radiation is calculated. The theory, where the energy loss of projectile has to be taken into account, agrees quite satisfactory with available CERN data. It is shown that the influence of multiple scattering on radiation process is suppressed due to action of crystal field.

  10. Title: Combined passive detection and ultrafast active imaging of cavitation events induced by short pulses of high intensity

    E-Print Network [OSTI]

    Boyer, Edmond

    1 Title: Combined passive detection and ultrafast active imaging of cavitation events induced by short pulses of high intensity ultrasound Authors: Jérôme GATEAU, Jean-François AUBRY, Mathieu PERNOT / INSERM, U979 / Université Denis Diderot, Paris VII Key words: single nucleation events, ultrafast active

  11. Enhancement of x-ray line emission from plasmas produced by short high-intensity laser double pulses

    E-Print Network [OSTI]

    Limpouch, Jiri

    Enhancement of x-ray line emission from plasmas produced by short high-intensity laser double.25.Os, 52.65. y I. INTRODUCTION The advanced technology of short pulse lasers now pro- vides on experimental conditions. The enhancement of x-ray yield by short laser prepulses has been reported in several

  12. A Model-Driven Architecture for Highly Distributed, Data-Intensive Systems Jet Propulsion Laboratory, May 2008

    E-Print Network [OSTI]

    Mattmann, Chris

    from unstructured and semi-structure information (ii) Scalable, secure, federated search (iii The Jet Propulsion Laboratory (JPL) has been researching and building data intensive systems for highly for both solar system and earth exploration, these systems have a number of critical architectural

  13. Laser-based proton acceleration on ultra-thin foil with a 100 TW class high intensity laser system

    E-Print Network [OSTI]

    Marjoribanks, Robin S.

    of electromagnetic fields in plasma, isotopes production or hadron therapy. The 100 TW class laser systemLaser-based proton acceleration on ultra-thin foil with a 100 TW class high intensity laser system. To characterize the plasma expansion, we monitor it with an imaging technique using a femtosecond laser probe

  14. Highly efficient second-harmonic generation of intense femtosecond pulses with a significant effect of cubic nonlinearity

    SciTech Connect (OSTI)

    Mironov, S Yu; Ginzburg, V N; Lozhkarev, V V; Luchinin, G A; Kirsanov, Aleksei V; Yakovlev, I V; Khazanov, Efim A; Shaykin, A A [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod (Russian Federation)

    2011-11-30T23:59:59.000Z

    A highly efficient (73%) second-harmonic generation of femtosecond pulses in a 1-mm-thick KDP crystal at a fundamentalharmonic peak intensity of 2 TW cm{sup -2} has been demonstrated experimentally. In a 0.5-mm-thick KDP crystal, a 50% efficiency has been reached at a peak intensity of 3.5 TW cm{sup -2}. We examine the key factors that limit the conversion efficiency and present numerical simulation results on further temporal compression of second-harmonic pulses.

  15. Solvated electron lithium electrode for high energy density battery

    SciTech Connect (OSTI)

    Sammells, A.F.

    1987-05-26T23:59:59.000Z

    A rechargeable high energy density lithium-based cell is described comprising: a solvated electron lithium negative electrode comprising a solution of lithium dissolved in liquid ammonia; a lithium ion conducting solid electrolyte contacting the negative electrode; a liquid non-aqueous lithium ion conducting electrolyte comprising a lithium ion conducting supporting electrolyte dissolved in a non-aqueous solvent. The liquid electrolyte contacting the lithium ion conducting solid electrolyte; and a solid lithium intercalation positive electrode contacting the liquid electrolyte.

  16. THE ELECTRON ION COLLIDER. A HIGH LUMINOSITY PROBE OF THE PARTONIC SUBSTRUCTURE OF NUCLEONS AND NUCLEI.

    SciTech Connect (OSTI)

    EDITED BY M.S. DAVIS

    2002-02-01T23:59:59.000Z

    By the end of this decade, the advancement of current and planned research into the fundamental structure of matter will require a new facility, the Electron Ion Collider (EIC). The EIC will collide high-energy beams of polarized electrons from polarized protons and neutrons, and unpolarized beams of electrons off atomic nuclei with unprecedented intensity. Research at the EIC will lead to a detailed understanding of the structure of the proton, neutron, and atomic nuclei as described by Quantum Chromo-Dynamics (QCD), the accepted theory of the strong interaction. The EIC will establish quantitative answers to important questions by delivering dramatically increased precision over existing and planned experiments and by providing completely new experimental capabilities. Indeed, the EIC will probe QCD in a manner not possible previously. This document presents the scientific case for the design, construction and operation of the EIC. While realization of the EIC requires a significant advance in the development of efficient means of producing powerful beams of energetic electrons, an important consideration for choosing the site of the EIC is the planned upgrade to the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. The upgrade planned for RHIC will fully meet the requirements for the ion beam for the EIC, providing a distinct advantage in terms of cost, schedule and the final operation.

  17. Thermal Properties of Graphene and Applications for Thermal Management of High-Power Density Electronics

    E-Print Network [OSTI]

    Yan, Zhong

    2013-01-01T23:59:59.000Z

    the development of high-power density semiconductor devices.Management of High-Power Density Electronics A DissertationManagement of High-Power Density Electronics by Zhong Yan

  18. Radial profile measurement of electron temperature in edge stochastic magnetic field layer of LHD using intensity ratio of extreme ultraviolet line emissions

    SciTech Connect (OSTI)

    Wang Erhui [Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Gifu (Japan); Morita, Shigeru; Kobayashi, Masahiko; Murakami, Izumi; Goto, Motoshi [Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Gifu (Japan); National Institute for Fusion Science, Toki 509-5292, Gifu (Japan); Dong Chunfeng [National Institute for Fusion Science, Toki 509-5292, Gifu (Japan)

    2012-10-15T23:59:59.000Z

    Vertical profile of neon line emissions in 30-650 A wavelength range has been observed in horizontally elongated plasma cross section of Large Helical Device (LHD). Intensity ratio between the neon line emissions is studied to measure the radial profile of electron temperature in the edge stochastic magnetic field layer of LHD. The edge temperature profile successfully obtained from the line ratio of NeVIII 2s-3p to 2p-3s transitions is compared with the simulation based on three-dimensional edge transport code. The result shows a reasonably good agreement with the edge temperature profile analyzed from atomic data and analysis structure code. The electron temperature at last closed flux surface measured from the intensity ratio is also in good agreement with that measured from Thomson scattering.

  19. Soft x-ray intensity profile measurements of electron cyclotron heated plasmas using semiconductor detector arrays in GAMMA 10 tandem mirror

    SciTech Connect (OSTI)

    Minami, R., E-mail: minami@prc.tsukuba.ac.jp; Imai, T.; Kariya, T.; Numakura, T.; Eguchi, T.; Kawarasaki, R.; Nakazawa, K.; Kato, T.; Sato, F.; Nanzai, H.; Uehara, M.; Endo, Y.; Ichimura, M. [Plasma Research Center, University of Tsukuba, Tsukuba, Ibaraki 305-8577 (Japan)

    2014-11-15T23:59:59.000Z

    Temporally and spatially resolved soft x-ray analyses of electron cyclotron heated plasmas are carried out by using semiconductor detector arrays in the GAMMA 10 tandem mirror. The detector array has 16-channel for the measurements of plasma x-ray profiles so as to make x-ray tomographic reconstructions. The characteristics of the detector array make it possible to obtain spatially resolved plasma electron temperatures down to a few tens eV and investigate various magnetohydrodynamic activities. High power electron cyclotron heating experiment for the central-cell region in GAMMA 10 has been started in order to reduce the electron drag by increasing the electron temperature.

  20. Two-dimensional electron momentum spectra of argon ionized by short intense lasers: Comparison of theory with experiment

    E-Print Network [OSTI]

    Lin, Chii-Dong

    by Rudenko et al. 11 show complex structures in the low-electron energy region. Arbó et al. 14 suggested

  1. Generation of high-current electron beam in a wide-aperture open discharge

    SciTech Connect (OSTI)

    Bokhan, P. A.; Zakrevsky, Dm. E.; Gugin, P. P. [A. V. Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, prospekt Lavrent'eva 13, Novosibirsk 630090 (Russian Federation)

    2011-10-15T23:59:59.000Z

    In the present study, it was examined generation of nanosecond-duration electron-beam (EB) pulses by a wide-aperture open discharge burning in helium or in a mixture of helium with nitrogen and water vapor. In the experiments, a discharge cell with coaxial electrode geometry, permitting radial injection of the electron beam into operating lasing medium, was used, with the cathode having radius 2.5 cm and length 12 cm. It was shown possible to achieve an efficient generation of a high-intensity electron beam (EB pulse power {approx}250 MW and EB pulse energy up to 4 J) in the kiloampere range of discharge currents (up to 26 kA at {approx}12 kV discharge voltage). The current-voltage characteristics of the discharge proved to be independent of the working-gas pressure. The existence of an unstable dynamic state of EB, conditioned by the presence of an uncompensated space charge accumulated in the discharge cell due to the exponential growth of the current in time during discharge initiation and the hyperbolic growth of current density in the direction towards the tube axis, was revealed. The obtained pulsed electron beam was used to excite the self-terminated laser on He 2{sup 1}P{sub 1}{sup 0}-2{sup 1}S{sub 0} transition. The oscillations developing in the discharge cell at high discharge currents put limit to the pumping energy and emissive power of the laser excited with the radially converging electron beam.

  2. Thermal Properties of Graphene and Applications for Thermal Management of High-Power Density Electronics

    E-Print Network [OSTI]

    Yan, Zhong

    2013-01-01T23:59:59.000Z

    Turin and A. A. Balandin, Electronics Letters 40, 81 (2004).REFERENCES G. E. Moore, Electronics 38 (1965). E. Pop, Nanofor High-power Electronics” PCSI-38:38th Conference on the

  3. Radiation from polarized electrons in oriented crystals at high energy

    E-Print Network [OSTI]

    V. N. Baier; V. M. Katkov

    2004-05-06T23:59:59.000Z

    Radiation from high energy electrons in an oriented crystal can be considered in a frame of the quasiclassical operator method which appears to be a most satisfactory approach to the problem. Under some quite generic assumptions the general expression is derived for the probability of circularly polarized photon emission from the longitudinally polarized electron in oriented crystal. The particular mechanism of radiation depends on interrelation between the angle of incidence $\\vartheta_0$ (angle between the momentum of initial electron and axis (plane) of crystal) and angle $\\vartheta_v \\equiv V_0/m$ ($V_0$ is the scale of a potential of axis or a plane relative to which the angle $\\vartheta_0$ is defined). When $\\vartheta_0 \\ll \\vartheta_v$ one has magnetic bremsstrahlung type of radiation (with corrections $\\propto \\vartheta_0^2$ which are due to inhomogeneous character of field in crystal). When $\\vartheta_0 \\gg \\vartheta_v$ one obtains the theory of coherent bremsstrahlung, while for $\\vartheta_0 \\geq \\vartheta_v$ one arrives to the modified theory of coherent bremsstrahlung. At high energy radiation in oriented crystals is strongly enhanced comparing with standard bremsstrahlung.

  4. Rapid thermal processing of steel using high energy electron beams

    SciTech Connect (OSTI)

    Elmer, J.W.; Newton, A.; Smith, C. Jr.

    1993-11-10T23:59:59.000Z

    High energy electron beams (HEEBs) with megavolt energies represent a new generation of charged particle beams that rapidly deposit up to several hundred joules/pulse over areas on the order of a few square millimeters to 100s of square centimeters. These pulsed beams have energies in the 1 to 10 MeV range, which enables the electrons to deposit large amounts of energy deeply into the material being processed, and these beams have short pulse durations (50 ns) that can heat materials at rates as high as 10{sup 10} {degrees}C/s for a 1000 {degree}C temperature rise in the material. Lower heating rates, on the order of 10{sup 4} {degrees}C/s, can be produced by reducing the energy per pulse and distributing the total required energy over a series of sub-ms pulses, at pulse repetition frequencies (PRFs) up to several kHz. This paper presents results from materials processing experiments performed on steel with a 6 MeV electron beam, analyzes these results using a Monte Carlo transport code, and presents a first-order predictive method for estimating the peak energy deposition, temperature, and heating rate for HEEB processed steel.

  5. High energy electron beam joining of ceramic components

    SciTech Connect (OSTI)

    Turman, B.N.; Glass, S.J.; Halbleib, J.A. [and others

    1997-07-01T23:59:59.000Z

    High strength, hermetic braze joints between ceramic components have been produced using high energy electron beams. With a penetration depth into a typical ceramic of {approximately}1 cm for a 10 MeV electron beam, this method provides the capability for rapid, transient brazing operations where temperature control of critical components is essential. The method deposits energy directly into a buried joint, allowing otherwise inaccessible interfaces to be brazed. Because of transient heating, higher thermal conductivity, lower heat capacity, and lower melting temperature of braze metals relative to the ceramic materials, a pulsed high power beam can melt a braze metal without producing excessive ceramic temperatures. We have demonstrated the feasibility of this process related to ceramic coupons as well as ceramic and glass tubes. The transient thermal response was predicted, using as input the energy absorption predicted from the coupled electron-photon transport analysis. The joining experiments were conducted with an RF Linac accelerator at 10-13 MV. The repetition rate of the pulsed beam was varied between 8 and 120 Hz, the average beam current was varied between 8 and 120 microamps, and the power was varied up to 1.5 kW. These beam parameters gave a beam power density between 0.2 to 2 kW/cm{sup 2}. The duration of the joining runs varied from 5 to 600 sec. Joining experiments have provided high strength between alumina - alumina and alumina - cermet joints in cylindrical geometry. These joints provided good hermetic seals. A series of tests was conducted to determine the minimum beam power and exposure time for producing, a hermetic seal.

  6. Microfabricated high-bandpass foucault aperture for electron microscopy

    DOE Patents [OSTI]

    Glaeser, Robert; Cambie, Rossana; Jin, Jian

    2014-08-26T23:59:59.000Z

    A variant of the Foucault (knife-edge) aperture is disclosed that is designed to provide single-sideband (SSB) contrast at low spatial frequencies but retain conventional double-sideband (DSB) contrast at high spatial frequencies in transmission electron microscopy. The aperture includes a plate with an inner open area, a support extending from the plate at an edge of the open area, a half-circle feature mounted on the support and located at the center of the aperture open area. The radius of the half-circle portion of reciprocal space that is blocked by the aperture can be varied to suit the needs of electron microscopy investigation. The aperture is fabricated from conductive material which is preferably non-oxidizing, such as gold, for example.

  7. Large dynamic range diagnostics for high current electron LINACs

    SciTech Connect (OSTI)

    Evtushenko, P., E-mail: Pavel.Evtushenko@jlab.org [Thomas Jefferson National Accelerator Facility 12000 Jefferson Avenue, Newport News, VA 23606 (United States)

    2013-11-07T23:59:59.000Z

    The Jefferson Lab FEL driver accelerator - Energy Recovery Linac has provided a beam with average current of up to 9 mA and beam energy of 135 MeV. The high power beam operations have allowed developing and testing methods and approaches required to set up and tune such a facility simultaneously for the high beam power and high beam quality required for high performance FEL operations. In this contribution we briefly review this experience and outline problems that are specific to high current - high power non-equilibrium linac beams. While the original strategy for beam diagnostics and tuning have proven to be quite successful, some shortcomings and unresolved issues were also observed. The most important issues are the non-equilibrium (non-Gaussian) nature of the linac beam and the presence of small intensity - large amplitude fraction of the beam a.k.a. beam halo. Thus we also present a list of the possible beam halo sources and discuss possible mitigations means. We argue that for proper understanding and management of the beam halo large dynamic range (>10{sup 6}) transverse and longitudinal beam diagnostics can be used. We also present results of transverse beam profile measurements with the dynamic range approaching 10{sup 5} and demonstrate the effect the increased dynamic range has on the beam characterization, i.e., emittance and Twiss parameters measurements. We also discuss near future work planned in this field and where the JLab FEL facility will be used for beam tests of the developed of new diagnostics.

  8. Determination of thickness and composition of high-k dielectrics using high-energy electrons

    SciTech Connect (OSTI)

    Grande, P. L. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia) [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia); Instituto de Física, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS (Brazil); Vos, M. [Atomic and Molecular Physics Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia)] [Atomic and Molecular Physics Laboratory, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia); Venkatachalam, D. K.; Elliman, R. G. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia)] [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia); Nandi, S. K. [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia) [Department of Electronic Materials Engineering, Research School of Physics and Engineering, The Australian National University, Canberra ACT 0200 (Australia); Research School of Astronomy and Astrophysics, The Australian National University, Canberra ACT 2611 (Australia); Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)

    2013-08-12T23:59:59.000Z

    We demonstrate the application of high-energy elastic electron backscattering to the analysis of thin (2–20 nm) HfO{sub 2} overlayers on oxidized Si substrates. The film composition and thickness are determined directly from elastic scattering peaks characteristic of each element. The stoichiometry of the films is determined with an accuracy of 5%–10%. The experimental results are corroborated by medium energy ions scattering and Rutherford backscattering spectrometry measurements, and clearly demonstrate the applicability of the technique for thin-film analysis. Significantly, the presented technique opens new possibilities for nm depth profiling with high spatial resolution in scanning electron microscopes.

  9. Reliability of GaN high electron mobility transistors on silicon substrates

    E-Print Network [OSTI]

    Demirtas, Sefa

    2009-01-01T23:59:59.000Z

    GaN High Electron Mobility Transistors are promising devices for high power and high frequency applications such as cellular base stations, radar and wireless network systems, due to the high bandgap and high breakdown ...

  10. Solar wind-magnetosphere coupling leading to relativistic electron energization during high-speed streams

    E-Print Network [OSTI]

    Lyons, Larry

    Solar wind-magnetosphere coupling leading to relativistic electron energization during high. Smith (2005), Solar wind-magnetosphere coupling leading to relativistic electron energization during. Using observations during a period of persistent high-speed, corotating, solar wind streams, we

  11. Two-gigawatt burst-mode operation of the intense microwave prototype (IMP) free-electron laser (FEL) for the microwave tokamak experiment (MTX)

    SciTech Connect (OSTI)

    Felker, B.; Allen, S.; Bell, H. [and others

    1993-10-06T23:59:59.000Z

    The MTX explored the plasma heating effects of 140 GHz microwaves from both Gyrotrons and from the IMP FEL wiggler. The Gyrotron was long pulse length (0.5 seconds maximum) and the FEL produced short-pulse length, high-peak power, single and burst modes of 140 GHZ microwaves. Full-power operations of the IMP FEL wiggler were commenced in April of 1992 and continued into October of 1992. The Experimental Test Accelerator H (ETA-II) provided a 50-nanosecond, 6-MeV, 2--3 kAmp electron beam that was introduced co-linear into the IMP FEL with a 140 GHz Gyrotron master oscillator (MO). The FEL was able to amplify the MO signal from approximately 7 kW to peaks consistently in the range of 1--2 GW. This microwave pulse was transmitted into the MTX and allowed the exploration of the linear and non-linear effects of short pulse, intense power in the MTX plasma. Single pulses were used to explore and gain operating experience in the parameter space of the IMP FEL, and finally evaluate transmission and absorption in the MTX. Single-pulse operations were repeatable. After the MTX was shut down burst-mode operations were successful at 2 kHz. This paper will describe the IMP FEL, Microwave Transmission System to MTX, the diagnostics used for calorimetric measurements, and the operations of the entire Microwave system. A discussion of correlated and uncorrelated errors that affect FEL performance will be made Linear and non-linear absorption data of the microwaves in the MTX plasma will be presented.

  12. High-Temperature Air-Cooled Power Electronics Thermal Design (Presentation)

    SciTech Connect (OSTI)

    Waye, S.

    2014-06-01T23:59:59.000Z

    This presentation discusses the status of research at NREL on high temperature air-cooled power electronics thermal design.

  13. Self-pinched transport of a high ?/? electron beam

    SciTech Connect (OSTI)

    Myers, M. C.; Wolford, M. F.; Sethian, J. D. [U.S. Naval Research Laboratory, Plasma Physics Division, 4555 Overlook Ave., SW, Washington DC 20375 (United States)] [U.S. Naval Research Laboratory, Plasma Physics Division, 4555 Overlook Ave., SW, Washington DC 20375 (United States); Rose, D. V. [Voss Scientific, 418 Washington St. SE, Albuquerque, New Mexico 87108 (United States)] [Voss Scientific, 418 Washington St. SE, Albuquerque, New Mexico 87108 (United States); Hegeler, F. [Commonwealth Technology Inc., 5875 Barclay Drive, Alexandria, Virginia 22315 (United States)] [Commonwealth Technology Inc., 5875 Barclay Drive, Alexandria, Virginia 22315 (United States)

    2013-10-15T23:59:59.000Z

    The self-pinched transport of a 0.5 MeV, 18 kA cylindrical electron beam has been studied experimentally and computationally. The relatively low voltage and high current required for materials surface modification applications leads to complicated beam dynamics as the Alfven limit is approached. Transport and focusing of the high ?/? beam was done in a sub-Torr, neutral gas-filled, conducting tube in the ion-focused regime. In this regime, beam space charge forces are progressively neutralized to allow focusing of the beam by its self-magnetic field. The beam exhibits stable envelope oscillations as it is efficiently and reproducibly propagated for distances greater than a betatron wavelength. Experimental results follow the trends seen in 2-D particle-in-cell simulations. Results show that the input electron beam can be periodically focused to a peaked profile with the beam half-current radius decreased by a factor of 2.84. This results in an increase of a factor of 8 in beam current density. This focusing is sufficient to produce desired effects in the surface layers of metallic materials.

  14. Pulsed laser deposition with a high average power free electron laser: Benefits of subpicosecond pulses with high repetition rate

    E-Print Network [OSTI]

    Reilly, Anne

    Pulsed laser deposition with a high average power free electron laser: Benefits of subpicosecond average power Thomas Jefferson National Accelerator Facility Free Electron Laser. The combination of the free electron laser leads to very different plasma emission and produces films with high quality

  15. Observation of a Long-Wavelength Hosing Modulation of a High-Intensity Laser Pulse in Underdense Plasma

    E-Print Network [OSTI]

    Kaluza, M C; Thomas, A G R; Najmudin, Z; Dangor, A E; Murphy, C D; Collier, J L; Divall, E J; Foster, P S; Hooker, C J; Langley, A J; Smith, J; Krushelnick, K

    2010-01-01T23:59:59.000Z

    We report the first experimental observation of a long-wavelength hosing modulation of a high-intensity laser pulse. Side-view images of the scattered optical radiation at the fundamental wave-length of the laser reveal a transverse oscillation of the laser pulse during its propagation through underdense plasma. The wavelength of the oscillation \\lambda_hosing depends on the background plasma density n_e and scales as \\lambda_hosing~n_e^-3/2. Comparisons with an analytical model and 2-dimensional particle-in-cell simulations reveal that this laser hosing can be induced by a spatio-temporal asymmetry of the intensity distribution in the laser focus which can be caused by a misalignment of the parabolic focussing mirror or of the diffraction gratings in the pulse compressor.

  16. Dominant deuteron acceleration with a high-intensity laser for isotope production and neutron generation

    SciTech Connect (OSTI)

    Maksimchuk, A.; Raymond, A.; Yu, F.; Dollar, F.; Willingale, L.; Zulick, C.; Krushelnick, K. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Petrov, G. M.; Davis, J. [Naval Research Laboratory, Plasma Physics Division, Washington, DC 20375 (United States)] [Naval Research Laboratory, Plasma Physics Division, Washington, DC 20375 (United States)

    2013-05-13T23:59:59.000Z

    Experiments on the interaction of an ultra-short pulse laser with heavy-water, ice-covered copper targets, at an intensity of 2 Multiplication-Sign 10{sup 19} W/cm{sup 2}, were performed demonstrating the generation of a 'pure' deuteron beam with a divergence of 20 Degree-Sign , maximum energy of 8 MeV, and a total of 3 Multiplication-Sign 10{sup 11} deuterons with energy above 1 MeV-equivalent to a conversion efficiency of 1.5%{+-} 0.2%. Subsequent experiments on irradiation of a {sup 10}B sample with deuterons and neutron generation from d-d reactions in a pitcher-catcher geometry, resulted in the production of {approx}10{sup 6} atoms of the positron emitter {sup 11}C and a neutron flux of (4{+-}1) Multiplication-Sign 10{sup 5} neutrons/sterad, respectively.

  17. High Intensity Compton Scattering in a strong plane wave field of general form

    E-Print Network [OSTI]

    A. Hartin; G. Moortgat-Pick

    2011-06-24T23:59:59.000Z

    Photon emission by an electron embedded in a strong external field of general form is studied theoretically. The external field considered is a plane wave electromagnetic field of any number of components, period and polarisation. Exact, Volkov solutions of the Dirac equation with the 4-potential of the general external field are obtained. The photon emission is considered in the usual perturbation theory using the Volkov solutions to represent the electron. An expression for the transition probability of this process is obtained after the usual spin and polarisation sums, trace calculation and phase space integration. The final transition probability in the general case contains a single sum over contributions from external field photons and an integration over one of the phase space components. The validity of the general expression is established by considering specific external fields. Known specific analytic forms of the transition probability are obtained after substitution of the 4-potential for a circularly polarised and constant crossed external field. As an example usage of the general result for the transition probability, the case of two phase separated, circularly polarised external fields is studied both analytically and numerically.

  18. Experimental investigation of electron multipactor discharges at very high frequency

    E-Print Network [OSTI]

    Graves, Timothy P. (Timothy Paul)

    2006-01-01T23:59:59.000Z

    Multipactor discharges are a resonant condition in which electrons impact a surface in phase with an alternating electric field. The discharge is sustained by electron multiplication from secondary emission. As motivation, ...

  19. Solar-wind magnetosphere coupling, including relativistic electron energization, during high-speed streams

    E-Print Network [OSTI]

    Lyons, Larry

    Solar-wind­ magnetosphere coupling, including relativistic electron energization, during high. If this inference is correct, and if it is chorus that energizes the relativistic electrons, then high-speed solar-speed solar wind streams, and fluxes of relativistic electrons observed at geosynchronous orbit enhance

  20. High-harmonic generation in plasmas from relativistic laser-electron scattering

    E-Print Network [OSTI]

    Umstadter, Donald

    High-harmonic generation in plasmas from relativistic laser-electron scattering S. Banerjee, A. R Results are presented on the generation of high harmonics through the scattering of relativistic electrons to be the emission of even- order harmonics, linear dependence on the electron density, significant amount

  1. Adapting High Brightness Relativistic Electron Beams for Ultrafast Science

    E-Print Network [OSTI]

    Scoby, Cheyne Matthew

    2012-01-01T23:59:59.000Z

    1989. [96] A. Yariv and P. Yeh. Optical Waves in Crystals:Mar 2008. [95] Amnon Yariv. Quantum electronics. Wiley,

  2. Role of the electronic structure and multielectron responses in ionization mechanisms of diatomic molecules in intense short-pulse lasers: An all-electron ab initio study

    E-Print Network [OSTI]

    Chu, Shih-I; Chu, Xi

    2004-12-14T23:59:59.000Z

    . 1(b) and 1(c), respectively; a 1pg electron in Fig. 2(c) has a smaller ionization probability than a 3sg or a 2pu electron in TABLE I. Comparison of calculated binding energies of di- atomic molecules and experimental values. Molecule Bond length sa0...] M. J. DeWitt, E. Wells, and R. R. Jones, Phys. Rev. Lett. 87, 153001 (2001). [12] E. Wells, M. J. DeWitt, and R. R. Jones, Phys. Rev. A 66, 013409 (2002). [13] X. M. Tong, Z. X. Zhao, and C. D. Lin, Phys. Rev. A 66, 033402 (2002). [14] H. R. Reiss...

  3. Solvated electron lithium electrode for high energy density battery

    SciTech Connect (OSTI)

    Sammels, A.F.

    1987-08-04T23:59:59.000Z

    A solvated electron lithium negative electrode is described containing: containment means holding a solution of lithium dissolved in liquid ammonia to form a solvated electron solution, the solvated electron solution contacting a lithium intercalating membrane and providing lithium to the intercalating membrane during discharge and accepting it from the intercalating membrane during charge.

  4. PLASMA FOCUSING OF HIGH ENERGY DENSITY ELECTRON AND POSITRON BEAMS \\Lambda

    E-Print Network [OSTI]

    PLASMA FOCUSING OF HIGH ENERGY DENSITY ELECTRON AND POSITRON BEAMS \\Lambda J.S.T. Ng, P. Chen, W present results from the SLAC E­150 experiment on plasma focusing of high energy density electron and of the SLAC E­150 experiment are to study plasma focusing for high energy, high density par­ ticle beams

  5. Nuclear {gamma}-ray coincidence experiments in high-intensity photon beams

    SciTech Connect (OSTI)

    Savran, D.; Loeher, B. [ExtreMe Matter Institute EMMI and Research Devision, GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany) and Frankfurt Institute for Advanced Studies FIAS, Frankfurt am Main (Germany)

    2012-07-09T23:59:59.000Z

    High energy photons are an important experimental probe in nuclear structure physics and have been used in the past decades for the investigation of low-spin structures of atomic nuclei. A topic of particular interest in recent years in this field is the Pygmy Dipole Resonance, an electric dipole (E1) excitation mode located well below the E1 giant resonance. Even though the PDR has been investigated systematically using high energy photons its decay properties were not accessible up to now. New experiments using the method of {gamma}-{gamma} coincidences will allow to study this important quantity in detail.

  6. Electron Scattering From High-Momentum Neutrons in Deuterium

    SciTech Connect (OSTI)

    A.V. Klimenko; S.E. Kuhn

    2005-10-12T23:59:59.000Z

    We report results from an experiment measuring the semi-inclusive reaction D(e,e'p{sub s}) where the proton p{sub s} is moving at a large angle relative to the momentum transfer. If we assume that the proton was a spectator to the reaction taking place on the neutron in deuterium, the initial state of that neutron can be inferred. This method, known as spectator tagging, can be used to study electron scattering from high-momentum (off-shell) neutrons in deuterium. The data were taken with a 5.765 GeV electron beam on a deuterium target in Jefferson Laboratory's Hall B, using the CLAS detector. A reduced cross section was extracted for different values of final-state missing mass W*, backward proton momentum {rvec p}{sub s} and momentum transfer Q{sup 2}. The data are compared to a simple PWIA spectator model. A strong enhancement in the data observed at transverse kinematics is not reproduced by the PWIA model. This enhancement can likely be associated with the contribution of final state interactions (FSI) that were not incorporated into the model. A ''bound neutron structure function'' F{sub 2n}{sup eff} was extracted as a function of W* and the scaling variable x* at extreme backward kinematics, where effects of FSI appear to be smaller. For p{sub s} > 400 MeV/c, where the neutron is far off-shell, the model overestimates the value of F{sub 2n}{sup eff} in the region of x* between 0.25 and 0.6. A modification of the bound neutron structure function is one of possible effects that can cause the observed deviation.

  7. Electron Scattering From High-Momentum Neutrons in Deuterium

    E-Print Network [OSTI]

    A. V. Klimenko; S. E. Kuhn; for the CLAS collaboration

    2005-10-12T23:59:59.000Z

    We report results from an experiment measuring the semi-inclusive reaction $d(e,e'p_s)$ where the proton $p_s$ is moving at a large angle relative to the momentum transfer. If we assume that the proton was a spectator to the reaction taking place on the neutron in deuterium, the initial state of that neutron can be inferred. This method, known as spectator tagging, can be used to study electron scattering from high-momentum (off-shell) neutrons in deuterium. The data were taken with a 5.765 GeV electron beam on a deuterium target in Jefferson Laboratory's Hall B, using the CLAS detector. A reduced cross section was extracted for different values of final-state missing mass $W^{*}$, backward proton momentum $\\vec{p}_{s}$ and momentum transfer $Q^{2}$. The data are compared to a simple PWIA spectator model. A strong enhancement in the data observed at transverse kinematics is not reproduced by the PWIA model. This enhancement can likely be associated with the contribution of final state interactions (FSI) that were not incorporated into the model. A ``bound neutron structure function'' $F_{2n}^{eff}$ was extracted as a function of $W^{*}$ and the scaling variable $x^{*}$ at extreme backward kinematics, where effects of FSI appear to be smaller. For $p_{s}>400$ MeV/c, where the neutron is far off-shell, the model overestimates the value of $F_{2n}^{eff}$ in the region of $x^{*}$ between 0.25 and 0.6. A modification of the bound neutron structure function is one of possible effects that can cause the observed deviation.

  8. High-speed silicon electro-optic modulator for electronic photonic integrated circuits

    E-Print Network [OSTI]

    Gan, Fuwan

    2007-01-01T23:59:59.000Z

    The development of future electronic-photonic integrated circuits (EPIC) based on silicon technology critically depends on the availability of CMOS-compatible high-speed modulators that enable the interaction of electronic ...

  9. HIGH INTENSITY LINAC DRIVER FOR THE SPIRAL-2 PROJECT : DESIGN OF SUPERCONDUCTING 88 MHZ QUARTER WAVE

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    . For the high-energy section of the linac, a superconducting 88 MHz Quarter Wave Resonator (beta 0.12) has been WAVE RESONATORS (BETA 0.12), POWER COUPLERS AND CRYOMODULES T. Junquera, G. Olry, H. Saugnac, J Abstract A superconducting linac driver, delivering deuterons with an energy up to 40 MeV (5 mA) and heavy

  10. Electron beam diagnostic for profiling high power beams

    DOE Patents [OSTI]

    Elmer, John W. (Danville, CA); Palmer, Todd A. (Livermore, CA); Teruya, Alan T. (Livermore, CA)

    2008-03-25T23:59:59.000Z

    A system for characterizing high power electron beams at power levels of 10 kW and above is described. This system is comprised of a slit disk assembly having a multitude of radial slits, a conducting disk with the same number of radial slits located below the slit disk assembly, a Faraday cup assembly located below the conducting disk, and a start-stop target located proximate the slit disk assembly. In order to keep the system from over-heating during use, a heat sink is placed in close proximity to the components discussed above, and an active cooling system, using water, for example, can be integrated into the heat sink. During use, the high power beam is initially directed onto a start-stop target and after reaching its full power is translated around the slit disk assembly, wherein the beam enters the radial slits and the conducting disk radial slits and is detected at the Faraday cup assembly. A trigger probe assembly can also be integrated into the system in order to aid in the determination of the proper orientation of the beam during reconstruction. After passing over each of the slits, the beam is then rapidly translated back to the start-stop target to minimize the amount of time that the high power beam comes in contact with the slit disk assembly. The data obtained by the system is then transferred into a computer system, where a computer tomography algorithm is used to reconstruct the power density distribution of the beam.

  11. Laser sustained discharge nozzle apparatus for the production of an intense beam of high kinetic energy atomic species

    DOE Patents [OSTI]

    Cross, J.B.; Cremers, D.A.

    1986-01-10T23:59:59.000Z

    Laser sustained discharge apparatus for the production of intense beams of high kinetic energy atomic species is described. A portion of the plasma resulting from a laser sustained continuous optical discharge which generates energetic atomic species from a gaseous source thereof is expanded through a nozzle into a region of low pressure. The expanded plasma contains a significant concentration of the high kinetic energy atomic species which may be used to investigate the interaction of surfaces therewith. In particular, O-atoms having velocities in excess of 3.5 km/s can be generated for the purpose of studying their interaction with materials in order to develop protective materials for spacecraft which are exposed to such energetic O-atoms during operation in low earth orbit.

  12. Design Optimisation of a High Intensity Beam Facility and Feasibility Experiment of a Solid Fragmented Target

    E-Print Network [OSTI]

    Charitonidis, Nikolaos; Rivkin, Leonid

    2014-06-13T23:59:59.000Z

    The present PhD thesis describes the design, execution and results of the HRMT-10 experiment performed at the HiRadMat facility of the CERN/SPS complex. The ?rst part of the thesis covers the design optimization studies of the HiRadMat facility, focusing in particular on the radiation protection issues. A detailed Monte-Carlo model of the facility has been developed and validated through comparison with measurements. A very satisfactory agreement between the simulation and the experimental data is observed. In the second part of this thesis, a novel feasibility experiment of a fragmented solid target for a future Neutrino Factory or a Super Beam facility, able to support high beam powers ( 1 MW) is presented in detail. A solid granular target has been proposed as an interesting alternative to an open Hg jet target, presently considered as the baseline for such facilities, but posing considerable technical challenges. The HRMT-10 experiment seeks to address the lack of experimental data of the feasibility of...

  13. Benchmark of the IMPACT Code for High Intensity Beam DynamicsSimulation

    SciTech Connect (OSTI)

    Qiang, J.; Ryne, R.D.

    2006-11-16T23:59:59.000Z

    The IMPACT (Integrated Map and Particle Accelerator Tracking) code was first developed under Computational Grand Challenge project in the mid 1990s [1]. It started as a three-dimensional (3D) data parallel particle-in-cell (PIC) code written in High Performance Fortran. The code used a split-operator based method to solve the Hamiltonian equations of motion. It contained linear transfer maps for drifts, quadrupole magnets and rf cavities. The space-charge forces were calculated using an FFT-based method with 3D open boundary conditions and longitudinal periodic boundary conditions. This code was completely rewritten in the late 1990s based on a message passing parallel programming paradigm using Fortran 90 and MPI following an object-oriented software design. This improved the code's scalability on large parallel computer systems and also gave the code better software maintainability and extensibility [2]. In the following years, under the SciDAC-1 accelerator project, the code was extended to include more accelerating and focusing elements such as DTL, CCL, superconducting linac, solenoid, dipole, multipoles, and others. Besides the original split-operator based integrator, a direct integration of Lorentz equations of motion using a leap-frog algorithm was also added to the IMPACT code to handle arbitrary external nonlinear fields. This integrator can read in 3D electromagnetic fields in a Cartesian grid or in a cylindrical coordinate system. Using the Lorentz integrator, we also extended the original code to handle multiple charge-state beams. The space-charge solvers were also extended to include conducting wall effects for round and rectangular pipes with longitudinal open and periodic boundary conditions. Recently, it has also been extended to handle short-range wake fields (longitudinal monopole and transverse dipole) and longitudinal coherent synchrotron radiation wake fields. Besides the parallel macroparticle tracking code, an rf linac lattice design code, an envelope matching and analysis code, and a number of pre- and post-processing codes were also developed to form the IMPACT code suite. The IMPACT code suite has been used to study beam dynamics in the SNS linac, the J-PARC linac commissioning, the CERN superconducting linac design, the Los Alamos Low Energy Demonstration Accelerator (LEDA) halo experiment, the Rare Isotope Accelerator (RIA) driver linac design, and the FERMI{at}Elettra FEL linac design [3-8]. It has also been used to study space-charge resonance in anisotropic beams [9-11].

  14. Air Cooling for High Temperature Power Electronics (Presentation)

    SciTech Connect (OSTI)

    Waye, S.; Musselman, M.; King, C.

    2014-09-01T23:59:59.000Z

    Current emphasis on developing high-temperature power electronics, including wide-bandgap materials such as silicon carbide and gallium nitride, increases the opportunity for a completely air-cooled inverter at higher powers. This removes the liquid cooling system for the inverter, saving weight and volume on the liquid-to-air heat exchanger, coolant lines, pumps, and coolant, replacing them with just a fan and air supply ducting. We investigate the potential for an air-cooled heat exchanger from a component and systems-level approach to meet specific power and power density targets. A proposed baseline air-cooled heat exchanger design that does not meet those targets was optimized using a parametric computational fluid dynamics analysis, examining the effects of heat exchanger geometry and device location, fixing the device heat dissipation and maximum junction temperature. The CFD results were extrapolated to a full inverter, including casing, capacitor, bus bar, gate driver, and control board component weights and volumes. Surrogate ducting was tested to understand the pressure drop and subsequent system parasitic load. Geometries that met targets with acceptable loads on the system were down-selected for experimentation. Nine baseline configuration modules dissipated the target heat dissipation, but fell below specific power and power density targets. Six optimized configuration modules dissipated the target heat load, exceeding the specific power and power density targets. By maintaining the same 175 degrees C maximum junction temperature, an optimized heat exchanger design and higher device heat fluxes allowed a reduction in the number of modules required, increasing specific power and power density while still maintaining the inverter power.

  15. Fast magnetic field annihilation in the relativistic collisionless regime driven by two ultra-short high-intensity laser pulses

    E-Print Network [OSTI]

    Gu, Y J; Kumar, D; Liu, Y; Singh, S K; Esirkepov, T Zh; Bulanov, S V; Weber, S; Korn, G

    2015-01-01T23:59:59.000Z

    The magnetic quadrupole structure formation during the interaction of two ultra-short high power laser pulses with a collisionless plasma is demonstrated with 2.5-dimensional particle-in-cell simulations. The subsequent expansion of the quadrupole is accompanied by magnetic field annihilation in the ultrarelativistic regime, when the magnetic field can not be sustained by the plasma current. This results in a dominant contribution of the displacement current exciting a strong large scale electric?field. This field leads to the conversion of magnetic energy into kinetic energy of accelerated electrons inside the thin current sheet.

  16. Extension of high-order harmonic generation cutoff via coherent control of intense few-cycle chirped laser pulses

    E-Print Network [OSTI]

    Carrera, Juan J.; Chu, Shih-I

    2007-03-16T23:59:59.000Z

    for larger dis- tances. #1;b#2; A second-order split-operator technique in the en- ergy representation, which allows the explicit elimination of undesirable fast-oscillating high-energy components, is used for the efficient time propagation of the wave... potential and the laser field. It then oscil- lates quasifreely driven by the Lorenz force and acquires kinetic energy from the laser field. Lastly, after the laser reverses its direction, the returning electron will emit har- monic photons by radiative...

  17. Development of a high average current polarized electron source with long cathode operational lifetime

    SciTech Connect (OSTI)

    C. K. Sinclair; P. A. Adderley; B. M. Dunham; J. C. Hansknecht; P. Hartmann; M. Poelker; J. S. Price; P. M. Rutt; W. J. Schneider; M. Steigerwald

    2007-02-01T23:59:59.000Z

    Substantially more than half of the electromagnetic nuclear physics experiments conducted at the Continuous Electron Beam Accelerator Facility of the Thomas Jefferson National Accelerator Facility (Jefferson Laboratory) require highly polarized electron beams, often at high average current. Spin-polarized electrons are produced by photoemission from various GaAs-based semiconductor photocathodes, using circularly polarized laser light with photon energy slightly larger than the semiconductor band gap. The photocathodes are prepared by activation of the clean semiconductor surface to negative electron affinity using cesium and oxidation. Historically, in many laboratories worldwide, these photocathodes have had short operational lifetimes at high average current, and have often deteriorated fairly quickly in ultrahigh vacuum even without electron beam delivery. At Jefferson Lab, we have developed a polarized electron source in which the photocathodes degrade exceptionally slowly without electron emission, and in which ion back bombardment is the predominant mechanism limiting the operational lifetime of the cathodes during electron emission. We have reproducibly obtained cathode 1/e dark lifetimes over two years, and 1/e charge density and charge lifetimes during electron beam delivery of over 2?105???C/cm2 and 200 C, respectively. This source is able to support uninterrupted high average current polarized beam delivery to three experimental halls simultaneously for many months at a time. Many of the techniques we report here are directly applicable to the development of GaAs photoemission electron guns to deliver high average current, high brightness unpolarized beams.

  18. High-energy high-luminosity electron-ion collider eRHIC

    SciTech Connect (OSTI)

    Litvinenko, V.N.; Ben-Zvi, I.; Hammons, L.; Hao, Y.; Webb, S.; et al

    2011-08-09T23:59:59.000Z

    In this paper, we describe a future electron-ion collider (EIC), based on the existing Relativistic Heavy Ion Collider (RHIC) hadron facility, with two intersecting superconducting rings, each 3.8 km in circumference. The replacement cost of the RHIC facility is about two billion US dollars, and the eRHIC will fully take advantage and utilize this investment. We plan adding a polarized 5-30 GeV electron beam to collide with variety of species in the existing RHIC accelerator complex, from polarized protons with a top energy of 325 GeV, to heavy fully-striped ions with energies up to 130 GeV/u. Brookhaven's innovative design, is based on one of the RHIC's hadron rings and a multi-pass energy-recovery linac (ERL). Using the ERL as the electron accelerator assures high luminosity in the 10{sup 33}-10{sup 34} cm{sup -2} sec{sup -1} range, and for the natural staging of eRHIC, with the ERL located inside the RHIC tunnel. The eRHIC will provide electron-hadron collisions in up to three interaction regions. We detail the eRHIC's performance in Section 2. Since first paper on eRHIC paper in 2000, its design underwent several iterations. Initially, the main eRHIC option (the so-called ring-ring, RR, design) was based on an electron ring, with the linac-ring (LR) option as a backup. In 2004, we published the detailed 'eRHIC 0th Order Design Report' including a cost-estimate for the RR design. After detailed studies, we found that an LR eRHIC has about a 10-fold higher luminosity than the RR. Since 2007, the LR, with its natural staging strategy and full transparency for polarized electrons, became the main choice for eRHIC. In 2009, we completed technical studies of the design and dynamics for MeRHIC with 3-pass 4 GeV ERL. We learned much from this evaluation, completed a bottom-up cost estimate for this $350M machine, but then shelved the design. In the same year, we turned again to considering the cost-effective, all-in-tunnel six-pass ERL for our design of the high-luminosity eRHIC. In it, electrons from the polarized pre-injector will be accelerated to their top energy by passing six times through two SRF linacs. After colliding with the hadron beam in up to three detectors, the e-beam will be decelerated by the same linacs and dumped. The six-pass magnetic system with small-gap magnets will be installed from the start. We will stage the electron energy from 5 GeV to 30 GeV stepwise by increasing the lengths of the SRF linacs. We discuss details of eRHIC's layout in Section 3. We considered several IR designs for eRHIC. The latest one, with a 10 mrad crossing angle and {beta}* = 5 cm, takes advantage of newly commissioned Nb{sub 3}Sn quadrupoles. Section 4 details the eRHIC lattice and the IR layout. The current eRHIC design focuses on electron-hadron collisions. If justified by the EIC physics, we will add a 30 GeV polarized positron ring with full energy injection from eRHIC ERL. This addition to the eRHIC facility provide for positron-hadron collisions, but at a significantly lower luminosity than those attainable in the electron-hadron mode. As a novel high-luminosity EIC, eRHIC faces many technical challenges, such as generating 50 mA of polarized electron current. eRHIC also will employ coherent electron cooling (CeC) for the hadron beams. Staff at BNL, JLab, and MIT is pursuing vigorously an R&D program for resolving addressing these obstacles. In collaboration with Jlab, BNL plans experimentally to demonstrate CeC at the RHIC. We discuss the structure and the status of the eRHIC R&D in Section 5.

  19. Relativistic self-focusing of ultra-high intensity X-ray laser beams in warm quantum plasma with upward density profile

    SciTech Connect (OSTI)

    Habibi, M., E-mail: habibi.physics@gmail.com [Young Researchers and Elite Club, Shirvan Branch, Islamic Azad University, Shirvan (Iran, Islamic Republic of); Ghamari, F. [Young Researchers and Elite Club, Khorramabad Branch, Islamic Azad University, Khorramabad (Iran, Islamic Republic of)

    2014-05-15T23:59:59.000Z

    The results of a numerical study of high-intensity X-ray laser beam interaction with warm quantum plasma (WQP) are presented. By means of an upward ramp density profile combined with quantum factors specially the Fermi velocity, we have demonstrated significant relativistic self-focusing (RSF) of a Gaussian electromagnetic beam in the WQP where the Fermi temperature term in the dielectric function is important. For this purpose, we have considered the quantum hydrodynamics model that modifies refractive index of inhomogeneous WQPs with the inclusion of quantum correction through the quantum statistical and diffraction effects in the relativistic regime. Also, to better illustration of the physical difference between warm and cold quantum plasmas and their effect on the RSF, we have derived the envelope equation governing the spot size of X-ray laser beam in Q-plasmas. In addition to the upward ramp density profile, we have found that the quantum effects would be caused much higher oscillation and better focusing of X-ray laser beam in the WQP compared to that of cold quantum case. Our computational results reveal the importance of the use of electrons density profile and Fermi speed in enhancing self-focusing of laser beam.

  20. Suppression of high-order-harmonic intensities observed in aligned CO{sub 2} molecules with 1300-nm and 800-nm pulses

    SciTech Connect (OSTI)

    Kato, Kosaku; Minemoto, Shinichirou; Sakai, Hirofumi [Department of Physics, Graduate School of Science, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

    2011-08-15T23:59:59.000Z

    High-order-harmonic generation from aligned N{sub 2}, O{sub 2}, and CO{sub 2} molecules is investigated by 1300-nm and 800-nm pulses. The harmonic intensities of 1300-nm pulses from aligned molecules show harmonic photon energy dependence similar to those of 800-nm pulses. Suppression of harmonic intensity from aligned CO{sub 2} molecules is observed for both 1300- and 800-nm pulses over the same harmonic photon energy range. As the dominant mechanism for the harmonic intensity suppression from aligned CO{sub 2} molecules, the present results support the two-center interference picture rather than the dynamical interference picture.

  1. Device and method for electron beam heating of a high density plasma

    DOE Patents [OSTI]

    Thode, Lester E. (Los Alamos, NM)

    1981-01-01T23:59:59.000Z

    A device and method for relativistic electron beam heating of a high density plasma in a small localized region. A relativistic electron beam generator produces a high voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target plasma is ionized prior to application of the electron beam by means of a laser or other preionization source. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region within the high density plasma target.

  2. Chapter 19. High Voltage Insulation, Diagnostics and Energetic Electron and Photon Beam Interactions

    E-Print Network [OSTI]

    Chapter 19. High Voltage Insulation, Diagnostics and Energetic Electron and Photon Beam Interactions 19-1 High Voltage Insulation, Diagnostics and Energetic Electron and Photon Beam Interactions 1. DC Properties of Modern Filled Epoxy Insulation Academic and Research Staff Dr. Chathan Cooke Sponsor

  3. RRR Degradation and Gas Absorption in the Electron Beam Welding Area of High Purity

    E-Print Network [OSTI]

    1 RRR Degradation and Gas Absorption in the Electron Beam Welding Area of High Purity Niobium W degradation and gas absorption of high purity niobium welded at different electron beam (EB) facilities are summarized. The oxygen and nitrogen content is increased as a rule at the welding seam. The absorption

  4. Vertical design of cubic GaN-based high electron mobility transistors R. Granzner,1,a)

    E-Print Network [OSTI]

    As, Donat Josef

    Vertical design of cubic GaN-based high electron mobility transistors R. Granzner,1,a) E. Tschumak 2011; accepted 24 October 2011; published online 1 December 2011) Cubic (zinc blende) AlGaN=GaN heterostructures for application in GaN-based high electron mobility transistors are investigated theoretically

  5. Effects of high-intensity ultrasound on Bi2Sr2CaCu2O8+x superconductor Tanya Prozorov

    E-Print Network [OSTI]

    Prozorov, Ruslan

    half of the speed of sound in liquid. Effective tem- peratures at the point of impact can easily exceed In liquid- powder slurries irradiated with high-intensity ultrasound, acoustic cavitation induces turbulent temperatures, 5000 K, and pressures, 300 Mpa,7­9 and the shockwaves launched into the liquid create high

  6. High current, low emittance, steady state electron guns with plasma cathodes

    SciTech Connect (OSTI)

    Hershcovitch, A.

    1995-12-31T23:59:59.000Z

    Major limitations of plasma cathodes have been overcome in an electron gun based on extraction of superthermal electrons from a discharge characterized by a large component of high energy electrons with a low thermal spread. A grid is employed to select these electrons for extraction while retaining the bulk electrons in the discharge. Steady state extraction of electron beams corresponding to over 60% of the total arc discharge current has been observed. A perveance of over 280 microperv was reached with the extraction of 9A at 1 keV from a 6 nun aperture. Some of the characteristics of the electron beam described in this paper are very attractive for electron beam melting.

  7. Electronic-Structure of High-Temperature Superconductors

    E-Print Network [OSTI]

    RICHERT, BA; Allen, Roland E.

    1988-01-01T23:59:59.000Z

    along 1 Z, demonstrate the two dimen- sionality of the electronic structure. 4's For this triple perovskite structure, there are now three antibonding Cu(d)-0(p) bands protruding above Ep at M and M'. Two of them are nearly the same...

  8. Testing of Performance of Optical Fibers Under Irradiation in Intense Radiation Fields, When Subjected to Very High Temperatures

    SciTech Connect (OSTI)

    Blue, Thomas; Windl, Wolfgang; Dickerson, Bryan

    2013-01-03T23:59:59.000Z

    The primary objective of this project is to measure and model the performance of optical fibers in intense radiation fields when subjected to very high temperatures. This research will pave the way for fiber optic and optically based sensors under conditions expected in future high-temperature gas-cooled reactors. Sensor life and signal-to-noise ratios are susceptible to attenuation of the light signal due to scattering and absorbance in the fibers. This project will provide an experimental and theoretical study of the darkening of optical fibers in high-radiation and high-temperature environments. Although optical fibers have been studied for moderate radiation fluence and flux levels, the results of irradiation at very high temperatures have not been published for extended in-core exposures. Several previous multi-scale modeling efforts have studied irradiation effects on the mechanical properties of materials. However, model-based prediction of irradiation-induced changes in silica�s optical transport properties has only recently started to receive attention due to possible applications as optical transmission components in fusion reactors. Nearly all damage-modeling studies have been performed in the molecular-dynamics domain, limited to very short times and small systems. Extended-time modeling, however, is crucial to predicting the long-term effects of irradiation at high temperatures, since the experimental testing may not encompass the displacement rate that the fibers will encounter if they are deployed in the VHTR. The project team will pursue such extended-time modeling, including the effects of the ambient and recrystallization. The process will be based on kinetic MC modeling using the concept of amorphous material consisting of building blocks of defect-pairs or clusters, which has been successfully applied to kinetic modeling in amorphized and recrystallized silicon. Using this procedure, the team will model compensation for rate effects, and the interplay of rate effects with the effects of annealing, to accurately predict the fibers� reliability and expected lifetime

  9. Characterisation of a MeV Bremsstrahlung x-ray source produced from a high intensity laser for high areal density object radiography

    SciTech Connect (OSTI)

    Courtois, C.; Compant La Fontaine, A.; Bazzoli, S.; Bourgade, J. L.; Gazave, J.; Lagrange, J. M.; Landoas, O.; Dain, L. Le; Pichoff, N. [CEA, DAM, DIF, F-91297 Arpajon (France)] [CEA, DAM, DIF, F-91297 Arpajon (France); Edwards, R.; Aedy, C. [AWE Plc., Aldermaston, Reading RG7 4PR (United Kingdom)] [AWE Plc., Aldermaston, Reading RG7 4PR (United Kingdom); Mastrosimone, D.; Pien, G.; Stoeckl, C. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)] [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States)

    2013-08-15T23:59:59.000Z

    Results of an experiment to characterise a MeV Bremsstrahlung x-ray emission created by a short (<10 ps) pulse, high intensity (1.4 × 10{sup 19} W/cm{sup 2}) laser are presented. X-ray emission is characterized using several diagnostics; nuclear activation measurements, a calibrated hard x-ray spectrometer, and dosimeters. Results from the reconstructed x-ray energy spectra are consistent with numerical simulations using the PIC and Monte Carlo codes between 0.3 and 30 MeV. The intense Bremsstrahlung x-ray source is used to radiograph an image quality indicator (IQI) heavily filtered with thick tungsten absorbers. Observations suggest that internal features of the IQI can be resolved up to an external areal density of 85 g/cm{sup 2}. The x-ray source size, inferred by the radiography of a thick resolution grid, is estimated to be approximately 400 ?m (full width half maximum of the x-ray source Point Spread Function)

  10. Graphene electron cannon: High-current edge emission from aligned graphene sheets

    SciTech Connect (OSTI)

    Liu, Jianlong; Li, Nannan; Guo, Jing; Fang, Yong; Deng, Jiang [National Key Laboratory of Science and Technology on Vacuum Electronics, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zeng, Baoqing, E-mail: bqzeng@uestc.edu.cn [National Key Laboratory of Science and Technology on Vacuum Electronics, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China); State Key Laboratory of Electronic Thin Films and Integrated Devices Zhongshan Lab, Department of Electronic Engineering, University of Electronic Science and Technology of China Zhongshan Institute, Zhongshan 528402 (China); Wang, Wenzhong; Li, Jiangnan; Hao, Chenchun [School of Science, Minzu University of China, Beijing 100081 (China)

    2014-01-13T23:59:59.000Z

    High-current field emitters are made by graphene paper consist of aligned graphene sheets. Field emission luminance pattern shows that their electron beams can be controlled by rolling the graphene paper from sheet to cylinder. These specific electron beams would be useful to vacuum devices and electron beam lithograph. To get high-current emission, the graphene paper is rolled to array and form graphene cannon. Due to aligned emission array, graphene cannon have high emission current. Besides high emission current, the graphene cannon is also tolerable with excellent emission stability. With good field emission properties, these aligned graphene emitters bring application insight.

  11. Exploring electronic structure through high-resolution hard x...

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

    Laboratory Modern high brilliance beamlines coupled with recent advances in hard-x-ray optics are establishing high-resolution hard x-ray spectroscopies as a powerful analytical...

  12. Design and implementation of a Client-Server System for Acquiring Beam Intensity Data from High Energy Accelerators at CERN

    E-Print Network [OSTI]

    Topaloudis, A; Bellas, N; Jensen, L

    The world’s largest research center in the domain of High Energy Physics (HEP) is the European Organization for Nuclear Research (CERN) whose main goal is to accelerate particles through a sequence of accelerators – accelerator complex – and bring them into collision in order to study the fundamental elements of matter and the forces acting between them. For controlling the accelerator complex, CERN needs several diagnostic tools to provide information about the beam’s attributes and one such system is the Fast Beam Current Transformer (FBCT) measuring system that provides bunch-by-bunch and total beam intensity information. The current hardware and firmware of the FBCT system has certain issues and lacks diagnostics as a lot of the calculations are done in an FPGA. In order to improve on this, the firmware was redesigned and simplified in order to increase its capabilities and provide the base of a unified FBCT measuring system that could be installed in several of CERN’s accelerator complex’s pa...

  13. Management of Respiratory Motion in Extracorporeal High-Intensity Focused Ultrasound Treatment in Upper Abdominal Organs: Current Status and Perspectives

    SciTech Connect (OSTI)

    Muller, A., E-mail: arnaud.muller@chu-lyon.fr [Centre Hospitalier Lyon Sud, Service de Radiologie, Hospices Civils de Lyon (France); Petrusca, L.; Auboiroux, V. [University of Geneva, Department of Radiology, Faculty of Medicine (Switzerland)] [University of Geneva, Department of Radiology, Faculty of Medicine (Switzerland); Valette, P. J. [Centre Hospitalier Lyon Sud, Service de Radiologie, Hospices Civils de Lyon (France)] [Centre Hospitalier Lyon Sud, Service de Radiologie, Hospices Civils de Lyon (France); Salomir, R. [University of Geneva, Department of Radiology, Faculty of Medicine (Switzerland)] [University of Geneva, Department of Radiology, Faculty of Medicine (Switzerland); Cotton, F. [Centre Hospitalier Lyon Sud, Service de Radiologie, Hospices Civils de Lyon (France)] [Centre Hospitalier Lyon Sud, Service de Radiologie, Hospices Civils de Lyon (France)

    2013-12-15T23:59:59.000Z

    Extracorporeal high-intensity focused ultrasound (HIFU) is a minimally invasive therapy considered with increased interest for the ablation of small tumors in deeply located organs while sparing surrounding critical tissues. A multitude of preclinical and clinical studies have showed the feasibility of the method; however, concurrently they showed several obstacles, among which the management of respiratory motion of abdominal organs is at the forefront. The aim of this review is to describe the different methods that have been proposed for managing respiratory motion and to identify their advantages and weaknesses. First, we specify the characteristics of respiratory motion for the liver, kidneys, and pancreas and the problems it causes during HIFU planning, treatment, and monitoring. Second, we make an inventory of the preclinical and clinical approaches used to overcome the problem of organ motion. Third, we analyze their respective benefits and drawbacks to identify the remaining physical, technological, and clinical challenges. We thereby consider the outlook of motion compensation techniques and those that would be the most suitable for clinical use, particularly under magnetic resonance thermometry monitoring.

  14. High and low frequency instabilities driven by a single electron beam in two-electron temperature space plasmas

    SciTech Connect (OSTI)

    Mbuli, L. N. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200, Republic of South Africa (South Africa) [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200, Republic of South Africa (South Africa); University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa); Maharaj, S. K. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200, Republic of South Africa (South Africa)] [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200, Republic of South Africa (South Africa); Bharuthram, R. [University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa)] [University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa)

    2013-12-15T23:59:59.000Z

    In an attempt to understand the excitation mechanisms of broadband electrostatic noise, beam-generated electrostatic instabilities are investigated using kinetic theory in a four-component magnetised plasma model composed of beam electrons (magnetic field-aligned), background hot and cool electrons and ions. All species are fully magnetised and considered to be Maxwellian. The dependence of the instability growth rates and real frequencies on various plasma parameters such as beam speed, particle densities and temperatures, magnetic field strength, wave propagation angle, and temperature anisotropy of the beam are examined. In this study we have found that the electron-acoustic, electron beam-resonant and ion-acoustic instabilities are excited. Our studies have focused on three velocity regimes, namely, the low (v{sub dbz}high velocity (v{sub dbz}>2 C{sub h}) regimes, where v{sub dbz} (C{sub h}) is the electron beam drift speed (thermal speed of the hot electrons). Plasma parameters from satellite measurements are used where applicable to provide realistic predictions.

  15. Transmission of High-Power Electron Beams Through Small Apertures

    SciTech Connect (OSTI)

    Tschalaer, Christoph [MIT Bates Linear Accelerator; Alarcon, Ricardo O.; Balascuta, S.; Benson, Stephen V. [JLAB; Bertozzi, William; Boyce, James R. [College of William and Mary; Cowan, Ray Franklin [MIT; Douglas, David R. [JLAB; Evtushenko, Pavel [JLAB; Fisher, Peter H.; Ihloff, Ernest E. [MIT Bates Linear Accelerator; Kalantarians, Narbe [Unversity of Texas; Kelleher, Aidan Michael [MIT Bates Linear Accelerator; Legg, Robert A. [JLAB; Milner, Richard; Neil, George R. [JLAB; Ou, Longwu [MIT; Schmookler, Barak Abraham [MIT; Tennant, Christopher D. [JLAB; Williams, Gwyn P. [JLAB; Zhang, Shukui [JLAB

    2013-11-01T23:59:59.000Z

    Tests were performed to pass a 100 MeV, 430 kWatt c.w. electron beam from the energy-recovery linac at the Jefferson Laboratory's FEL facility through a set of small apertures in a 127 mm long aluminum block. Beam transmission losses of 3 p.p.m. through a 2 mm diameter aperture were maintained during a 7 hour continuous run.

  16. Dynamic T{sub 2}-mapping during magnetic resonance guided high intensity focused ultrasound ablation of bone marrow

    SciTech Connect (OSTI)

    Waspe, Adam C.; Looi, Thomas; Mougenot, Charles; Amaral, Joao; Temple, Michael; Sivaloganathan, Siv; Drake, James M. [Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada); Philips Healthcare Canada, Markham, ON, L6C 2S3 (Canada); Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada); Department of Applied Mathematics, University of Waterloo, Waterloo, ON, N2L 3G1 (Canada); Centre for Image Guided Innovation and Therapeutic Intervention, The Hospital for Sick Children, Toronto, ON, M5G 1X8 (Canada)

    2012-11-28T23:59:59.000Z

    Focal bone tumor treatments include amputation, limb-sparing surgical excision with bone reconstruction, and high-dose external-beam radiation therapy. Magnetic resonance guided high intensity focused ultrasound (MR-HIFU) is an effective non-invasive thermotherapy for palliative management of bone metastases pain. MR thermometry (MRT) measures the proton resonance frequency shift (PRFS) of water molecules and produces accurate (<1 Degree-Sign C) and dynamic (<5s) thermal maps in soft tissues. PRFS-MRT is ineffective in fatty tissues such as yellow bone marrow and, since accurate temperature measurements are required in the bone to ensure adequate thermal dose, MR-HIFU is not indicated for primary bone tumor treatments. Magnetic relaxation times are sensitive to lipid temperature and we hypothesize that bone marrow temperature can be determined accurately by measuring changes in T{sub 2}, since T{sub 2} increases linearly in fat during heating. T{sub 2}-mapping using dual echo times during a dynamic turbo spin-echo pulse sequence enabled rapid measurement of T{sub 2}. Calibration of T{sub 2}-based thermal maps involved heating the marrow in a bovine femur and simultaneously measuring T{sub 2} and temperature with a thermocouple. A positive T{sub 2} temperature dependence in bone marrow of 20 ms/ Degree-Sign C was observed. Dynamic T{sub 2}-mapping should enable accurate temperature monitoring during MR-HIFU treatment of bone marrow and shows promise for improving the safety and reducing the invasiveness of pediatric bone tumor treatments.

  17. Impact ionization in N-polar AlGaN/GaN high electron mobility transistors

    SciTech Connect (OSTI)

    Killat, N., E-mail: Nicole.Killat@bristol.ac.uk, E-mail: Martin.Kuball@bristol.ac.uk; Uren, M. J.; Kuball, M., E-mail: Nicole.Killat@bristol.ac.uk, E-mail: Martin.Kuball@bristol.ac.uk [Center for Device Thermography and Reliability (CDTR), H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Keller, S.; Kolluri, S.; Mishra, U. K. [Department of Electrical and Computer Engineering, University of Santa Barbara California, Santa Barbara, California 93106 (United States)

    2014-08-11T23:59:59.000Z

    The existence of impact ionization as one of the open questions for GaN device reliability was studied in N-polar AlGaN/GaN high electron mobility transistors. Electroluminescence (EL) imaging and spectroscopy from underneath the device gate contact revealed the presence of hot electrons in excess of the GaN bandgap energy even at moderate on-state bias conditions, enabling impact ionization with hole currents up to several hundreds of pA/mm. The detection of high energy luminescence from hot electrons demonstrates that EL analysis is a highly sensitive tool to study degradation mechanisms in GaN devices.

  18. HILL: The High-Intensity Laser Laboratory Core Team's Reply to Questions from the NNSA Experimental Facilities Panel

    SciTech Connect (OSTI)

    Albright, B J [Los Alamos National Laboratory

    2012-08-02T23:59:59.000Z

    Question 1 - The type of physics regimes that HILL can access for weapons studies is quite interesting. The question that arises for the proposal team is what priority does this type of experimental data have versus data that can be obtained with NIF, and Z. How does HILL rank in priority compared to MARIE 1.0 in terms of the experimental data it will provide? We reiterate that isochoric heating experiments to be conducted with HILL are complementary to the high energy density physics experiments at NIF and Z and uniquely access states of matter that neither other facility can access. It is our belief that HILL will enable several important questions, e.g., as related to mix morphology, radiation transfer from corrugated surfaces, and equations of state, to be run to ground through carefully diagnosed, 'unit-physics' experiments. Such experiments will substantially improve confidence in our computer models and provide a rigorous science basis for certification. Question 2 - A secondary question relates to the interests of LLNL and SNL in the physics that HILL can address. This should be spelled out clearly. I would like to see the other labs be part of the discussion regarding how important this capability would be if built. Both sister Labs have a keen interest in the physics enabled by high-intensity, high-energy lasers, as evinced by the Z Petawatt and NIF ARC upgrades to their signature facilities. LANL scientists have teamed with scientists from both Laboratories in high-intensity laser 'first experiments' envisioned for HILL and we fully intend to continue these profitable discussions going forward. In the preparation of the HILL proposal, feedback was solicited from the broader HEDP and weapons science communities. The consensus view was that HILL filled a critical gap and that there was a need for a facility like HILL to address outstanding questions in weapons science. It was recognized that co-location of HILL with a facility such as MaRIE 1.0, Z, NIF, or Omega may offer additional advantages and we would expect these to be explored and evaluated during the CD process. Question 3 - A laser/optics experts group should review this proposal to ensure the level of R&D is reasonable to provide a sufficient chance of success (>50%). In the preparation of the HILL proposal, we sent our proposal and cost estimates to laser designers/scientists across the complex. Though risks were identified with our design, the prevailing view of those we engaged was that the risks were appropriately represented by the TRL levels assigned and that the enabling R&D planned in our proposal was adequate for risk mitigation. Question 4 - More data and peer review is needed from its sister facilities around the world. It is our specific intent to conduct both scientific and technical workshops with the user community if the High Intensity Science field is further encouraged as part of the NNSA Roadmap. Question 5 - Does HILL have to be co-located with MARIE 1.0? Is that feasible from the point of view of TA-53 real estate? Multiple siting options were considered for HILL, including co-location with MaRIE 1.0 (the most cost-effective and flexible option), as well as in a separate, stand-alone building and in a retro-fitted existing building. The cost estimate included these contingencies and candidate locations for HILL in TA-53 were identified. There is actually significant space at TA-53 on the hill in the northeast end of the mesa. Question 6 - What would be the impact on the weapons program if this facility were NOT built? An inability to elucidate aspects of weapons science in the dense plasma regime and validate computer models for same. This will lead to reduced confidence in the computer tools used for certification. Question 7 - Will HILL allow some of the x-ray vulnerability studies proposed by SPARC? If so what does Sandia's vulnerability group think of this method versus SPARC. It is possible that some of the scope envisioned for SPARC could be achieved on HILL, although likely that the energy produced at HILL not bei

  19. The powerful high-voltage glow discharge electron gun and power unit on its base

    SciTech Connect (OSTI)

    Chernov, V.A. [All-Russian Electrotechnical Institute, Moscow (Russian Federation)

    1994-12-31T23:59:59.000Z

    The technical and operational characteristics and features of powerful electron gun with cold cathodes on the basis of high-voltage glow discharge (HGD) are submitted. The systems, ensuring their work are described. Some results of operation and applications of these non-traditional electron guns are presented.

  20. High pressure and synchrotron radiation studies of solid state electronic instabilities

    SciTech Connect (OSTI)

    Pifer, J.H.; Croft, M.C.

    1992-04-01T23:59:59.000Z

    This report discusses Eu and General Valence Instabilities; Ce Problem: L{sub 3} Spectroscopy Emphasis; Bulk Property Emphasis; Transition Metal Compound Electronic Structure; Electronic Structure-Phonon Coupling Studies; High Temperature Superconductivity and Oxide Materials; and Novel Materials Collaboration with Chemistry.

  1. ccsd00001969, Particle-in-cell simulations of high energy electron

    E-Print Network [OSTI]

    ccsd­00001969, version 2 ­ 23 Oct 2004 Particle-in-cell simulations of high energy electron energy electrons from the underdense plasmas are investigated using two dimensional particle- in-cell simulations. When the ratio of the laser power and a critical power of relativistic self

  2. Scanning electron microscopy study of carbon nanotubes heated at high temperatures in air

    E-Print Network [OSTI]

    . INTRODUCTION Because of their remarkable physical and electronic properties, carbon nanotubes are promising nanotubes in air,3,4 in an oxygen stream,5 or under a flow of carbon dioxide gas.6 Thinning of nanotubesScanning electron microscopy study of carbon nanotubes heated at high temperatures in air Xuekun Lu

  3. Multi-wavelength analysis of high energy electrons in solar flares: a case study of August 20, 2002 flare

    E-Print Network [OSTI]

    J. Kasparova; M. Karlicky; E. P. Kontar; R. A. Schwartz; B. R. Dennis

    2005-08-30T23:59:59.000Z

    A multi-wavelength spatial and temporal analysis of solar high energy electrons is conducted using the August 20, 2002 flare of an unusually flat (gamma=1.8) hard X-ray spectrum. The flare is studied using RHESSI, Halpha, radio, TRACE, and MDI observations with advanced methods and techniques never previously applied in the solar flare context. A new method to account for X-ray Compton backscattering in the photosphere (photospheric albedo) has been used to deduce the primary X-ray flare spectra. The mean electron flux distribution has been analysed using both forward fitting and model independent inversion methods of spectral analysis. We show that the contribution of the photospheric albedo to the photon spectrum modifies the calculated mean electron flux distribution, mainly at energies below 100 keV. The positions of the Halpha emission and hard X-ray sources with respect to the current-free extrapolation of the MDI photospheric magnetic field and the characteristics of the radio emission provide evidence of the closed geometry of the magnetic field structure and the flare process in low altitude magnetic loops. In agreement with the predictions of some solar flare models, the hard X-ray sources are located on the external edges of the Halpha emission and show chromospheric plasma heated by the non-thermal electrons. The fast changes of Halpha intensities are located not only inside the hard X-ray sources, as expected if they are the signatures of the chromospheric response to the electron bombardment, but also away from them.

  4. Electronic properties of doped Mott insulators and high temperature superconductors

    E-Print Network [OSTI]

    Ribeiro, Tiago Castro

    2005-01-01T23:59:59.000Z

    High-temperature superconducting cuprates, which are the quintessential example of a strongly correlated system and the most extensively studied materials after semiconductors, spurred the development in the fields of ...

  5. High intensity illumination effects in LiNbO3 and KTiOPO4 waveguides D. Eger, M. A. Arbore, and M. M. Fejer

    E-Print Network [OSTI]

    Fejer, Martin M.

    ; accepted for publication 16 April 1997 Quasi-phase-matched waveguides are known to degrade when generating to oper- ate at relatively high optical intensities and short wave- lengths, is degradation a photovoltaic current (J) is generated and consequently an electric field is formed which modifies

  6. Design of electronics for a high-resolution, multi-material, and modular 3D printer

    E-Print Network [OSTI]

    Kwan, Joyce G

    2013-01-01T23:59:59.000Z

    Electronics for a high-resolution, multi-material, and modular 3D printer were designed and implemented. The driver for a piezoelectric inkjet print head can fire its nozzles with one of three droplet sizes ranging from 6 ...

  7. High energy density capacitors for power electronic applications using nano-structure multilayer technology

    SciTech Connect (OSTI)

    Barbee, T.W. Jr.; Johnson, G.W.

    1995-09-01T23:59:59.000Z

    Power electronics applications are currently limited by capacitor size and performance. Only incremental improvements are anticipated in existing capacitor technologies, while significant performance advances are required in energy density and overall performance to meet the technical needs of the applications which are important for U.S. economic competitiveness. One application, the Power Electronic Building Block (PEBB), promises a second electronics revolution in power electronic design. High energy density capacitors with excellent electrical thermal and mechanical performance represent an enabling technology in the PEBB concept. We propose a continuing program to research and develop LLNL`s nano-structure multilayer technologies for making high voltage, high energy density capacitors. Our controlled deposition techniques are capable of synthesizing extraordinarily smooth sub-micron thick layers of dielectric and conductor materials. We have demonstrated that, with this technology, high voltage capacitors with an order of magnitude improvement in energy density are achievable.

  8. RF Power Degradation of GaN High Electron Mobility Transistors

    E-Print Network [OSTI]

    Joh, Jungwoo

    We have developed a versatile methodology to systematically investigate the RF reliability of GaN High-Electron Mobility Transistors. Our technique utilizes RF and DC figures of merit to diagnose the degradation of RF ...

  9. Radiochemical Transformation of High Pressure Methane under Gamma, Electron, and Neutron Irradiation

    E-Print Network [OSTI]

    Clemens, Jeffrey Tyler

    2014-05-01T23:59:59.000Z

    The chemical effects of irradiation on high pressure methane and noble gas mixtures were investigated using gamma, electron beam, and neutron irradiation sources. The gamma source used was the La-140 source from the Nuclear Science Center (NSC...

  10. Measurement of Channel Temperature in GaN High-Electron Mobility Transistors

    E-Print Network [OSTI]

    Joh, Jungwoo

    In this paper, a simple and reliable method to estimate the channel temperature of GaN high-electron mobility transistors (HEMTs) is proposed. The technique is based on electrical measurements of performance-related figures ...

  11. Interpretation of Ion Flux and Electron Temperature Profiles at the JET Divertor Target during High Recycling and Detached Plasmas

    E-Print Network [OSTI]

    Interpretation of Ion Flux and Electron Temperature Profiles at the JET Divertor Target during High Recycling and Detached Plasmas

  12. High density electronic circuit and process for making

    DOE Patents [OSTI]

    Morgan, William P. (Albuquerque, NM)

    1999-01-01T23:59:59.000Z

    High density circuits with posts that protrude beyond one surface of a substrate to provide easy mounting of devices such as integrated circuits. The posts also provide stress relief to accommodate differential thermal expansion. The process allows high interconnect density with fewer alignment restrictions and less wasted circuit area than previous processes. The resulting substrates can be test platforms for die testing and for multi-chip module substrate testing. The test platform can contain active components and emulate realistic operational conditions, replacing shorts/opens net testing.

  13. High density electronic circuit and process for making

    DOE Patents [OSTI]

    Morgan, W.P.

    1999-06-29T23:59:59.000Z

    High density circuits with posts that protrude beyond one surface of a substrate to provide easy mounting of devices such as integrated circuits are disclosed. The posts also provide stress relief to accommodate differential thermal expansion. The process allows high interconnect density with fewer alignment restrictions and less wasted circuit area than previous processes. The resulting substrates can be test platforms for die testing and for multi-chip module substrate testing. The test platform can contain active components and emulate realistic operational conditions, replacing shorts/opens net testing. 8 figs.

  14. Longitudinal Dynamics of Twin Electron Bunches in a High-energy Linac

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

    Zhang, Zhen; Ding, Yuantao; Marinelli, Agostino; Huang, Zhirong

    2015-03-01T23:59:59.000Z

    The recent development of two-color x-ray free-electron lasers, as well as the successful demonstration of high-gradient witness bunch acceleration in a plasma, have generated strong interest in electron bunch trains, where two or more electron bunches are generated, accelerated and compressed in the same accelerating bucket. In this paper we give a detailed analysis of a twin-bunch technique in a high-energy linac. This method allows the generation of two electron bunches with high peak current and independent control of time delay and energy separation. We #12;find that the wake#12;fields in the accelerator structures play an important role in the twin-bunch compression, and through analysis show that they can be used to extend the available time delay range. Based on the theoretical model and simulations we propose several methods to achieve larger time delay.

  15. High-gain X-ray free electron laser by beat-wave terahertz undulator

    SciTech Connect (OSTI)

    Chang, Chao; Hei, DongWei [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an City 710024 (China) [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an City 710024 (China); Institute of Energy, Tsinghua University, Beijing 100084 (China); Pellegrin, Claudio; Tantawi, Sami [SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94309 (United States)] [SLAC National Accelerator Laboratory, Stanford University, Stanford, California 94309 (United States)

    2013-12-15T23:59:59.000Z

    The THz undulator has a higher gain to realize a much brighter X-ray at saturation, compared with the optical undulator under the same undulator strength and beam quality. In order to fill the high-power THz gap and realize the THz undulator, two superimposed laser pulses at normal incidence to the electron-beam moving direction form an equivalent high-field THz undulator by the frequency difference to realize the high-gain X-ray Free electron laser. The pulse front tilt of lateral fed lasers is used to realize the electron-laser synchronic interaction. By PIC simulation, a higher gain and a larger X-ray radiation power by the beat wave THz undulator could be realized, compared with the optical undulator for the same electron beam parameters.

  16. Longitudinal Dynamics of Twin Electron Bunches in a High-energy Linac

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

    Zhang, Zhen; Tsinghua University, Beijing; Ding, Yuantao; Marinelli, Agostino; Huang, Zhirong

    2015-03-01T23:59:59.000Z

    The recent development of two-color x-ray free-electron lasers, as well as the successful demonstration of high-gradient witness bunch acceleration in a plasma, have generated strong interest in electron bunch trains, where two or more electron bunches are generated, accelerated and compressed in the same accelerating bucket. In this paper we give a detailed analysis of a twin-bunch technique in a high-energy linac. This method allows the generation of two electron bunches with high peak current and independent control of time delay and energy separation. We #12;find that the wake#12;fields in the accelerator structures play an important role in the twin-bunchmore »compression, and through analysis show that they can be used to extend the available time delay range. Based on the theoretical model and simulations we propose several methods to achieve larger time delay.« less

  17. A High Energy Electron and Photon Detector Simulation System

    E-Print Network [OSTI]

    Srikanta Sinha

    2008-10-02T23:59:59.000Z

    A detailed Monte-Carlo code has been developed from basic principles that simulates almost all of the basic photon and charged particle interactions. The code is used to derive the response functions of a high energy photon detector to incident beams of photons of various energies. The detector response matrices (DRMs) are calculated using this code. Deconvolution of an artificially generated spectrum is presented.

  18. A HIGH REPETITION PLASMA MIRROR FOR STAGED ELECTRON ACCELERATION

    SciTech Connect (OSTI)

    Sokollik, Thomas; Shiraishi, Satomi; Osterhoff, Jens; Evans, Eugene; Gonsalves, Anthony; Nakamura, Kei; vanTilborg, Jeroen; Lin, Chen; Toth, Csaba; Leemans, Wim

    2011-07-22T23:59:59.000Z

    In order to build a compact, staged laser plasma accelerator the in-coupling of the laser beam to the different stages represents one of the key issues. To limit the spatial foot print and thus to realize a high overall acceleration gradient, a concept has to be found which realizes this in-coupling within a few centimeters. We present experiments on a tape-drive based plasma mirror which could be used to reflect the focused laser beam into the acceleration stage.

  19. Electron Excitation Coefficients in Helium, Neon, Oxygen and Methane at High E/N

    SciTech Connect (OSTI)

    Nikitovic, Zeljka D. [Institute of Physics, P.O.B. 68, 11080 Belgrade (Serbia and Montenegro)

    2006-12-01T23:59:59.000Z

    Swarm analysis is performed by comparing experimental and calculated transport coefficients. Comparisons are repeated until a satisfactory agreement is achieved after modifications of the cross sections. We have made an analysis of our excitation coefficient data for neon and methane by using detailed Monte Carlo simulation scheme. In this work we also present experimental electron excitation coefficients for other gases: helium, neon and oxygen. We used a drift tube technique to measure the absolute emission intensities in low current self sustained Townsend type discharges.

  20. Hysteresis and Noise from Electronic Nematicity in High-Temperature Superconductors E. W. Carlson,1

    E-Print Network [OSTI]

    Carlson, Erica

    -temperature superconductors, in addition to superconductivity, there may exist various other types of order which breakHysteresis and Noise from Electronic Nematicity in High-Temperature Superconductors E. W. Carlson,1 reported in recent noise [8] and hysteresis [9,10] measure- ments on high-temperature superconductors

  1. High energy electrons and nuclear phenomena in petawatt laser-solid experiments

    SciTech Connect (OSTI)

    Cowan, T. E.; Ditmire, T.; Hatchett, S.; Pennington, D. M.; Perry, M. D.; Phillips, T. W.; Wilks, S. C.; Young, P. E. [Lawrence Livermore National Laboratory, Livermore, California (United States); Dong, B.; Takahashi, Y. [University of Alabama, Huntsville, Alabama (United States); Fountain, W.; Parnell, T. [Marshall Space Flight Center, Huntsville, Alabama (United States); Hunt, A. W. [Harvard University, Cambridge, Massachusetts (United States); Johnson, J. [University Space Research Association, Huntsville, Alabama (United States); Kuehl, T. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany)

    1999-07-12T23:59:59.000Z

    The Petawatt laser at LLNL has opened a new regime of laser-matter interactions in which the quiver motion of plasma electrons is fully relativistic with energies extending well above the threshold for nuclear processes. We have developed broad-band magnetic spectrometers to measure the spectrum of high-energy electrons produced in laser-solid target experiments at the Petawatt, and have found that in addition to the expected flux of {approx}few MeV electrons characteristic of the ponderomotive potential, there is a high energy component extending to {approx}100 MeV apparently from plasma acceleration in the underdense pre-formed plasma. The generation of hard bremsstrahlung, photo-nuclear reactions, and preliminary evidence for positron-electron pair production will be discussed.

  2. High energy electrons and nuclear phenomena in petawatt laser-solid experiments

    SciTech Connect (OSTI)

    Cowan, T.E.; Ditmire, T.; Hatchett, S.; Pennington, D.M.; Perry, M.D.; Phillips, T.W.; Wilks, S.C.; Young, P.E. [Lawrence Livermore National Laboratory, Livermore, California (United States)] Dong, B. [University of Alabama, Huntsville, Alabama (United States); Parnell, T.; Takahashi, Y. [Marshall Space Flight Center, Huntsville, Alabama (United States)] Hunt, A.W. [Harvard University, Cambridge, Massachusetts (United States)] Johnson, J. [University Space Research Association, Huntsville, Alabama (United States)] Kuehl, T. [Gesellschaft fuer Schwerionenforschung, Darmstadt (Germany)

    1999-07-01T23:59:59.000Z

    The Petawatt laser at LLNL has opened a new regime of laser-matter interactions in which the quiver motion of plasma electrons is fully relativistic with energies extending well above the threshold for nuclear processes. We have developed broad-band magnetic spectrometers to measure the spectrum of high-energy electrons produced in laser-solid target experiments at the Petawatt, and have found that in addition to the expected flux of {approximately}few MeV electrons characteristic of the ponderomotive potential, there is a high energy component extending to {approximately}100 MeV apparently from plasma acceleration in the underdense pre-formed plasma. The generation of hard bremsstrahlung, photo-nuclear reactions, and preliminary evidence for positron-electron pair production will be discussed. {copyright} {ital 1999 American Institute of Physics.}

  3. High-energy electrons from the muon decay in orbit: radiative corrections

    E-Print Network [OSTI]

    Szafron, Robert

    2015-01-01T23:59:59.000Z

    We determine the $\\mathcal{O}(\\alpha)$ correction to the energy spectrum of electrons produced in the decay of muons bound in atoms. We focus on the high-energy end of the spectrum that constitutes a background for the muon-electron conversion and will be precisely measured by the upcoming experiments Mu2e and COMET. The correction suppresses the background by about 20\\%.

  4. IEEEJOURNAL OF QUANTUMELECTRONICS, VOL. QE-21,NO. 7, JULY 1985 831 High-Gain Free Electron Lasers Using Induction

    E-Print Network [OSTI]

    Wurtele, Jonathan

    IEEEJOURNAL OF QUANTUMELECTRONICS, VOL. QE-21,NO. 7, JULY 1985 831 High-Gain Free Electron Lasers, AND J. S. WURTELE Abstract-High-power free electron lasers (FEL's) can be realized using induction. INTRODUCTION THE free electron laser (FEL)[11 can produce coherent radiation at wavelengths from

  5. Scope and limitations of high energy electron scattering in obtaining relevant structural information about atoms and molecules

    SciTech Connect (OSTI)

    Ketkar, S.N.

    1984-01-01T23:59:59.000Z

    During the course of this work experiments were undertaken to measure the scattering cross-sections for high energy electrons scattering from various target systems. The experiments can be broadly classified into two categories, one dealing with rather small systems and the other dealing with large systems (at least in the view of physicists). Although the experimental aspects, in so much as the experimental measurement of the intensities of the scattered electron is concerned, is the same for both the cases the motivation for performing the experiment is totally different. In the first case, simple atomic and molecular target systems, namely He, H/sub 2/ and D/sub 2/, are used. For such systems, good theoretical framework is available and critical comparisons of experimental cross sections are made with theoretical predictions. Attention is focussed mainly at small momentum transfer (up to 10A/sup -1/), and correlation and binding effects are studied. In the second case, somewhat larger molecular systems, namely naphthalene, anthraquinone, anthracene and dichromium tetraacetate are used. For such systems attention is focused at large momentum transfer (from 10 to 25 A/sup -1/) to obtain structural information about the molecules.

  6. Diagnosing ions and neutrals via n=2 excited hydrogen atoms in plasmas with high electron density and low electron temperature

    SciTech Connect (OSTI)

    Shumack, A. E.; Schram, D. C.; Biesheuvel, J.; Goedheer, W. J.; Rooij, G. J. van [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, Nieuwegein (Netherlands)

    2011-03-15T23:59:59.000Z

    Ion and neutral parameters are determined in the high electron density, magnetized, hydrogen plasma beam of an ITER divertor relevant plasma via measurements of the n=2 excited neutrals. Ion rotation velocity (up to 7 km/s) and temperature (2-3 eV{approx}T{sub e}) are obtained from analysis of H{alpha} spectra measured close to the plasma source. The methodology for neutral density determination is explained whereby measurements in the linear plasma beam of Pilot-PSI are compared to modeling. Ground-state atomic densities are obtained via the production rate of n=2 and the optical thickness of the Lyman-{alpha} transition (escape factor {approx}0.6) and yield an ionization degree >85% and dissociation degree in the residual gas of {approx}4%. A 30% proportion of molecules with a rovibrational excitation of more than 2 eV is deduced from the production rate of n=2 atoms. This proportion increases by more than a factor of 4 for a doubling of the electron density in the transition to ITER divertor relevant electron densities, probably because of a large increase in the production and confinement of ground-state neutrals. Measurements are made using laser-induced fluorescence (LIF) and absorption, the suitability of which are evaluated as diagnostics for this plasma regime. Absorption is found to have a much better sensitivity than LIF, mainly owing to competition with background emission.

  7. Searching for minicharged particles via birefringence, dichroism and Raman spectroscopy of the vacuum polarized by a high-intensity laser wave

    SciTech Connect (OSTI)

    Villalba-Chávez, S., E-mail: selymv@gmail.com; Müller, C., E-mail: c.mueller@tp1.uni-duesseldorf.de

    2013-12-15T23:59:59.000Z

    Absorption and dispersion of probe photons in the field of a high-intensity circularly polarized laser wave are investigated. The optical theorem is applied for determining the absorption coefficients in terms of the imaginary part of the vacuum polarization tensor. Compact expressions for the vacuum refraction indices and the photon absorption coefficients are obtained in various asymptotic regimes of interest. The outcomes of this analysis reveal that, far from the region relatively close to the threshold of the two-photon reaction, the birefringence and dichroism of the vacuum are small and, in some cases, strongly suppressed. On the contrary, in a vicinity of the region in which the photo-production of a pair occurs, these optical properties are manifest with lasers of moderate intensities. We take advantage of such a property in the search of minicharged particles by considering high-precision polarimetric experiments. In addition, Raman-like electromagnetic waves resulting from the inelastic part of the vacuum polarization tensor are suggested as an alternative form for finding exclusion limits on these hypothetical charge carriers. The envisaged parameters of upcoming high-intensity laser facilities are used for establishing upper bounds on the minicharged particles. -- Highlights: •Via dichroism and birefringence of the vacuum by a strong laser wave, minicharged particles can be probed. •The discovery potential is the highest in a vicinity of the first pair production threshold. •As alternative observable, Raman scattered waves are put forward.

  8. Laser-Energy Transfer and Enhancement of Plasma Waves and Electron Beams by Interfering High-Intensity Laser Pulses

    E-Print Network [OSTI]

    Umstadter, Donald

    603, Beijing 100080, People's Republic of China (Received 14 February 2003; published 25 November 2003 the higher-power to the lower-power pulse, increasing the amplitude of the plasma wave propagating- sible for the energy transfer in this case differs from that studied in previous long-pulse and low-power

  9. Design of High Luminosity Ring-Ring Electron- Light Ion Collider at CEBAF

    SciTech Connect (OSTI)

    Slawomir Bogacz; Antje Bruell; Jean Delayen; Yaroslav Derbenev; Rolf Ent; Joseph Grames; Andrew Hutton; Geoffrey Krafft; Rui Li; Nikolitsa Merminga; Benard Poelker; Bogdan Wojtsekhowski; Byung Yunn; Yuhong Zhang; C Montag

    2007-06-25T23:59:59.000Z

    Experimental studies of fundamental structure of nucleons require an electron-ion collider of a center-of-mass energy up to 90 GeV at luminosity up to 1035 cm-2s-1 with both beams polarized. A CEBAF-based collider of 9 GeV electrons/positrons and 225 GeV ions is envisioned to meet this science need and as a next step for CEBAF after the planned 12 GeV energy upgrade of the fixed target program. A ring-ring scheme of this collider developed recently takes advantage of the existing polarized electron CW beam from the CEBAF and a green-field design of an ion complex with electron cooling. We present a conceptual design and report design studies of this high-luminosity collider.

  10. High-Resolution Infrared and Electron-Diffraction Studies of Trimethylenecyclopropane ([3]-Radialene)

    SciTech Connect (OSTI)

    Wright, Corey R.; Holmes, Joshua; Nibler, Joseph W.; Hedberg, Kenneth; White, James D.; Hedberg, Lise; Weber, Alfons; Blake, Thomas A.

    2013-05-16T23:59:59.000Z

    Combined high-resolution spectroscopic, electron-diffraction, and quantum theoretical methods are particularly advantageous for small molecules of high symmetry and can yield accurate structures that reveal subtle effects of electron delocalization on molecular bonds. The smallest of the radialene compounds, trimethylenecyclopropane, [3]-radialene, has been synthesized and examined in the gas phase by these methods. The first high-resolution infrared spectra have been obtained for this molecule of D3h symmetry, leading to an accurate B0 rotational constant value of 0.1378629(8) cm-1, within 0.5% of the value obtained from electronic structure calculations (density functional theory (DFT) B3LYP/cc-pVTZ). This result is employed in an analysis of electron-diffraction data to obtain the rz bond lengths (in Ĺ): C-H = 1.072 (17), C-C = 1.437 (4), and C=C = 1.330 (4). The analysis does not lead to an accurate value of the HCH angle; however, from comparisons of theoretical and experimental angles for similar compounds, the theoretical prediction of 117.5? is believed to be reliable to within 2?. The effect of electron delocalization in radialene is to reduce the single C-C bond length by 0.07 Ĺ compared to that in cyclopropane.

  11. Much Ado about Microbunching: Coherent Bunching in High Brightness Electron Beams

    SciTech Connect (OSTI)

    Ratner, Daniel; /Stanford U. /SLAC

    2012-05-25T23:59:59.000Z

    The push to provide ever brighter coherent radiation sources has led to the creation of correspondingly bright electron beams. With billions of electrons packed into normalized emittances (phase space) below one micron, collective effects may dominate both the preservation and use of such ultra-bright beams. An important class of collective effects is due to density modulations within the bunch, or microbunching. Microbunching may be deleterious, as in the case of the Microbunching Instability (MBI), or it may drive radiation sources of unprecedented intensity, as in the case of Free Electron Lasers (FELs). In this work we begin by describing models of microbunching due to inherent beam shot noise, which sparks both the MBI as well as SLAC's Linac Coherent Light Source, the world's first hard X-ray laser. We first use this model to propose a mechanism for reducing the inherent beam shot noise as well as for predicting MBI effects. We then describe experimental measurements of the resulting microbunching at LCLS, including optical radiation from the MBI, as well as the first gain length and harmonic measurements from a hard X-ray FEL. In the final chapters, we describe schemes that use external laser modulations to microbunch light sources of the future. In these sections we describe coherent light source schemes for both both linacs and storage rings.

  12. INNER SHELL EXCITATION OF ATOMS AND MOLECULES BY ELECTRON IMPACT WITH HIGH ENERGY RESOLUTION

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    INNER SHELL EXCITATION OF ATOMS AND MOLECULES BY ELECTRON IMPACT WITH HIGH ENERGY RESOLUTION F. H resolution energy loss spectra for inner shell excited states, (2) the observa- tion of inner shell excited are the subject of the present review. The inner shell states that can usefully be studied with energy resolutions

  13. Stability of very-high pressure arc discharges against perturbations of the electron temperature

    SciTech Connect (OSTI)

    Benilov, M. S. [Departamento de Fisica, Ciencias Exactas e Engenharia, Universidade da Madeira, Largo do Municipio, Funchal 9000 (Portugal); Hechtfischer, U. [Philips Lighting, BU Automotive Lamps, Technology, Philipsstrasse 8, Aachen 52068 (Germany)

    2012-04-01T23:59:59.000Z

    We study the stability of the energy balance of the electron gas in very high-pressure plasmas against longitudinal perturbations, using a local dispersion analysis. After deriving a dispersion equation, we apply the model to a very high-pressure (100 bar) xenon plasma and find instability for electron temperatures, T{sub e}, in a window between 2400 K and 5500-7000 K x 10{sup 3} K, depending on the current density (10{sup 6}-10{sup 8} A/m{sup 2}). The instability can be traced back to the Joule heating of the electron gas being a growing function of T{sub e}, which is due to a rising dependence of the electron-atom collision frequency on T{sub e}. We then analyze the T{sub e} range occurring in very high-pressure xenon lamps and conclude that only the near-anode region exhibits T{sub e} sufficiently low for this instability to occur. Indeed, previous experiments have revealed that such lamps develop, under certain conditions, voltage oscillations accompanied by electromagnetic interference, and this instability has been pinned down to the plasma-anode interaction. A relation between the mechanisms of the considered instability and multiple anodic attachments of high-pressure arcs is discussed.

  14. Heat generation from electronics increases with the advent of high-density integrated circuit technology. To

    E-Print Network [OSTI]

    Boyer, Edmond

    circuit technology. To come up with the heat generation, microscale cooling has been thought as a promising technology. Prediction of heat transfer rate is crucial in design of microscale cooling device1 Abstract Heat generation from electronics increases with the advent of high-density integrated

  15. High Efficiency Interleaved Power Electronics Converter for wide operating power range

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    High Efficiency Interleaved Power Electronics Converter for wide operating power range K driving strategy for improving the efficiency of power converters even if they are not used is presented. Index Terms-Power converters, Interleaved, Power efficiency I. CONTEXTE, INTRODUCTION One

  16. In situ growth regime characterization of cubic GaN using reflection high energy electron diffraction

    E-Print Network [OSTI]

    As, Donat Josef

    from Knudsen cells. Cubic GaN layers were deposited at 720 °C directly on 3C-SiC substrates shutters the GaN surface was exposed to different Ga fluxes for a certain time. The substrate temperatureIn situ growth regime characterization of cubic GaN using reflection high energy electron

  17. Schottky-Drain Technology for AlGaN/GaN High-Electron Mobility Transistors

    E-Print Network [OSTI]

    Lu, Bin

    In this letter, we demonstrate 27% improvement in the buffer breakdown voltage of AlGaN/GaN high-electron mobility transistors (HEMTs) grown on Si substrate by using a new Schottky-drain contact technology. Schottky-drain ...

  18. Time-resolved electron thermal conduction by probing of plasma formation in transparent solids with high power subpicosecond laser pulses

    SciTech Connect (OSTI)

    Vu, B.T.V.

    1994-02-01T23:59:59.000Z

    This dissertation work includes a series of experimental measurements in a search for better understanding of high temperature (10{sup 4}-10{sup 6}K) and high density plasmas (10{sup 22}-10{sup 24}cm{sup {minus}3}) produced by irradiating a transparent solid target with high intensity (10{sup 13} - 10{sup 15}W/cm{sup 2}) and subpicosecond (10{sup {minus}12}-10{sup {minus}13}s) laser pulses. Experimentally, pump and probe schemes with both frontside (vacuum-plasma side) and backside (plasma-bulk material side) probes are used to excite and interrogate or probe the plasma evolution, thereby providing useful insights into the plasma formation mechanisms. A series of different experiments has been carried out so as to characterize plasma parameters and the importance of various nonlinear processes. Experimental evidence shows that electron thermal conduction is supersonic in a time scale of the first picosecond after laser irradiation, so fast that it was often left unresolved in the past. The experimental results from frontside probing demonstrate that upon irradiation with a strong (pump) laser pulse, a thin high temperature ({approximately}40eV) super-critical density ({approximately}10{sup 23}/cm{sup 3}) plasma layer is quickly formed at the target surface which in turn becomes strongly reflective and prevents further transmission of the remainder of the laser pulse. In the bulk region behind the surface, it is also found that a large sub-critical ({approximately}10{sup 18}/cm{sup 3}) plasma is produced by inverse Bremsstrahlung absorption and collisional ionization. The bulk underdense plasma is evidenced by large absorption of the backside probe light. A simple and analytical model, modified from the avalanche model, for plasma evolution in transparent materials is proposed to explain the experimental results. Elimination of the bulk plasma is then experimentally illustrated by using targets overcoated with highly absorptive films.

  19. Self-heating simulation of GaN-based metal-oxide-semiconductor high-electron-mobility transistors including hot electron

    E-Print Network [OSTI]

    Ye, Peide "Peter"

    Self-heating simulation of GaN-based metal-oxide-semiconductor high-electron-mobility transistors the results of self-heating simulations of the GaN-based MOS-HEMTs, including hot electron and quantum effects of the gate and source/drain extension lengths on both the output performance and self-heating is discussed

  20. Electron cyclotron harmonic resonances in high-frequency heating of the ionosphere

    SciTech Connect (OSTI)

    Kuo, Spencer P. [Polytechnic Institute of New York University, 6 MetroTech Center, Brooklyn, New York 11201 (United States)] [Polytechnic Institute of New York University, 6 MetroTech Center, Brooklyn, New York 11201 (United States)

    2013-09-15T23:59:59.000Z

    Electron acceleration by upper hybrid waves under cyclotron harmonic resonance interaction is studied. Theory is formulated; the analytical solutions in the second and fourth harmonic cyclotron resonance cases are obtained, and in the third harmonic case, a first order differential equation governing the evolution of the electron energy is derived. The theory is applied for explaining the generation of artificial ionization layers observed in high-frequency (HF) ionospheric heating experiments. The upper hybrid waves are assumed to be excited parametrically by the O-mode HF heating wave. As the decay mode is the lower hybrid wave, the excited upper hybrid waves have wavelengths ranging from 0.25 to 0.5 m, which are short enough to effectively incorporate the finite Larmour radius effect for the harmonic cyclotron resonance interactions as well as have a frequency bandwidth of about 20 kHz, which provides an altitude region of about 10 km for continuous harmonic cyclotron resonance interaction between electrons and descending waves in the slightly inhomogeneous geomagnetic field. The numerical results on electron acceleration show that electron fluxes with energies larger than 14 eV are generated in the three harmonic cases. These energetic electrons cause impact ionizations, which are descending to form artificial ionization layers at the bottom of the ionospheric F region.

  1. Experimentally characterizing the electronic structures of f-electron systems using advanced high resolution Fourier transform microwave spectroscopies

    SciTech Connect (OSTI)

    Cooke, Stephen, A

    2013-02-03T23:59:59.000Z

    We aim to (i) provide data that directly addresses the fundamental roles of actinide valence electrons in chemical bonding, and (ii) serve to provide prototypical data for the heavy element computational chemistry community. These goals will be achieved through the first pure rotational spectroscopic measurements on prototypical systems at ultra-high resolution. These systems encompass low oxidation state uranium and thorium compounds including, but not limited to, UX and ThX, X = F, Cl, Br, I, and UY and ThY, Y = O, S, and other simple U and Th-containing compounds. Our primary experimental tools involve time-domain rotational spectroscopy achieving line widths and resolutions of a few kHz.

  2. Modeling the interaction of high power ion or electron beams with solid target materials

    SciTech Connect (OSTI)

    Hassanein, A.M.

    1983-11-01T23:59:59.000Z

    Intense energy deposition on first wall materials and other components as a result of plasma disruptions in magnetic fusion devices are expected to cause melting and vaporization of these materials. The exact amount of vaporization losses and melt layer thickness are very important to fusion reactor design and lifetime. Experiments using ion or electron beams to simulate the disruption effects have different environments than the actual disruption conditions in fusion reactors. A model has been developed to accurately simulate the beam-target interactions so that the results from such experiments can be meaningful and useful to reactor design. This model includes a two dimensional solution of the heat conduction equation with moving boundaries. It is found that the vaporization and melting of the sample strongly depends on the characteristics of the beam spatial distribution, beam diameter, and on the power-time variation of the beam.

  3. Ultra-high-frequency chaos in a time-delay electronic device with band-limited feedback

    E-Print Network [OSTI]

    Illing, Lucas

    Ultra-high-frequency chaos in a time-delay electronic device with band-limited feedback Lucas- dynamical electronic device. It consists of a transistor-based nonlinearity, commercially of such a device, we explore the dynamics of an electronic circuit that consists of a simple transistor

  4. RHIC PRESSURE RISE AND ELECTRON CLOUD.

    SciTech Connect (OSTI)

    Zhang, S Y; Blaskiewicz, M; Cameron, P; Drees, P; Afischer, W; Gassner, D; Gullotta, J; He, P; Hseuh, H; Chuang, H; Iriso-Aziz, U; Lee, R; Mackay, W; Woerter, B; Ptitsyn, V; Ponnaiyan, V; Roser, T; Satogata, T; Smart, L; Trbojevic, D

    2003-05-12T23:59:59.000Z

    In RHIC high intensity operation, two types of pressure rise are currently of concern. The first type is at the beam injection, which seems to be caused by the electron multipacting, and the second is the one at the beam transition, where the electron cloud is not the dominant cause. The first type of pressure rise is limiting the beam intensity and the second type might affect the experiments background for very high total beam intensity. In this article, the pressure rises at RHIC are described, and preliminary study results are reported. Some of the unsettled issues and questions are raised, and possible counter measures are discussed.

  5. Computational and experimental characterization of high-brightness beams for femtosecond electron imaging and spectroscopy

    SciTech Connect (OSTI)

    Portman, J.; Zhang, H.; Tao, Z.; Makino, K.; Berz, M.; Duxbury, P. M.; Ruan, C.-Y. [Physics and Astronomy Department, Michigan State University, East Lansing, Michigan 48824 (United States)] [Physics and Astronomy Department, Michigan State University, East Lansing, Michigan 48824 (United States)

    2013-12-16T23:59:59.000Z

    Using a multilevel fast multipole method, coupled with the shadow imaging of femtosecond photoelectron pulses for validation, we quantitatively elucidate the photocathode, space charge, and virtual cathode physics, which fundamentally limit the spatiotemporal and spectroscopic resolution and throughput of ultrafast electron microscope (UEM) systems. We present a simple microscopic description to capture the nonlinear beam dynamics based on a two-fluid picture and elucidate an unexpected dominant role of image potential pinning in accelerating the emittance growth process. These calculations set theoretical limits on the performance of UEM systems and provide useful guides for photocathode design for high-brightness electron beam systems.

  6. Possible Routes to Frictionless Transport of Electronic Fluids in High-Temperature Superconductors

    E-Print Network [OSTI]

    Zotin K-H Chu

    2009-12-23T23:59:59.000Z

    Electric-field-driven transport of electronic fluids in metallic glasses as well as three-dimensional amorphous superconductors are investigated by using the verified approach which has been successfully adopted to study the critical transport of glassy solid helium in very low temperature environment. The critical temperatures related to the nearly frictionless transport of electronic fluids were found to be directly relevant to the superconducting temperature of amorphous superconductors after selecting specific activation energies. Our results imply that optimal shear-thinning is an effective way to reach high-temperature charged superfluidity or superconductivity.

  7. Forward production of high-energy electrons from megavoltage photon beams

    SciTech Connect (OSTI)

    Biggs, P.J.

    1987-09-01T23:59:59.000Z

    The forward production of high-energy electrons from materials with various atomic numbers from carbon to lead has been measured for megavoltage photon beams from 4- to 25-MV peak bremsstrahlung energy by placing a thin-window parallel-plate ionization chamber directly behind foils of the various materials. The relative forward production of electrons decreases with atomic number for energies less than or equal to10 MV until about Z = 50, after which it rises. For photon energies greater than or equal to15 MV, forward production increases with atomic number with a break point at Z--50, beyond which the curve becomes steeper.

  8. In situ characterization of GaN quantum dot growth with reflection high-energy electron diffraction and line-of-sight mass spectrometry

    E-Print Network [OSTI]

    Brown, J S; Koblmuller, G; Averbeck, R; Riechert, H; Speck, J S

    2006-01-01T23:59:59.000Z

    mass spectrometry and re?ection high-energy electronmass spectrometry ?QMS? and re?ection high-energy electron

  9. Ga adsorbate on (0001) GaN: In situ characterization with quadrupole mass spectrometry and reflection high-energy electron diffraction

    E-Print Network [OSTI]

    Brown, J S; Koblmuller, G; Wu, F; Averbeck, R; Riechert, H; Speck, J S

    2006-01-01T23:59:59.000Z

    mass spectrometry and re?ection high-energy electronmass spectrometry ?QMS? and re?ection high-energy electron

  10. Non-Invasive Beam Detection in a High-Average Power Electron Accelerator

    SciTech Connect (OSTI)

    Williams, J. [Colorado State U.; Biedron, S. [Colorado State U.; Harris, J. [Colorado State U.; Martinez, J. [Colorado State U.; Milton, S. V. [Colorado State U.; Van Keuren, J. [Colorado State U.; Benson, Steve V. [JLAB; Evtushenko, Pavel [JLAB; Neil, George R. [JLAB; Zhang, Shukui [JLAB

    2013-12-01T23:59:59.000Z

    For a free-electron laser (FEL) to work effectively the electron beam quality must meet exceptional standards. In the case of an FEL operating at infrared wavelengths in an amplifier configuration the critical phase space tends to be in the longitudinal direction. Achieving high enough longitudinal phase space density directly from the electron injector system of such an FEL is difficult due to space charge effects, thus one needs to manipulate the longitudinal phase space once the beam energy reaches a sufficiently high value. However, this is fraught with problems. Longitudinal space charge and coherent synchrotron radiation can both disrupt the overall phase space, furthermore, the phase space disruption is exacerbated by the longitudinal phase space manipulation process required to achieve high peak current. To achieve and maintain good FEL performance one needs to investigate the longitudinal emittance and be able to measure it during operation preferably in a non-invasive manner. Using the electro-optical sampling (EOS) method, we plan to measure the bunch longitudinal profile of a high-energy (~120-MeV), high-power (~10kW or more FEL output power) beam.

  11. Collective Thomson scattering of a high power electron cyclotron resonance heating beam in LHD (invited)

    SciTech Connect (OSTI)

    Kubo, S.; Nishiura, M.; Tanaka, K.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Takahash, H.; Mutoh, T. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki, 509-5292 Gifu (Japan); Tamura, N. [Department of Energy Science and Technology, Nagoya University, Nagoya 464-8463 (Japan); Tatematsu, Y.; Saito, T. [Research Center for Development of FIR Region, University of Fukui, Fukui 910-8507 (Japan); Notake, T. [Tera-Photonics Lab., RIKEN, Sendai 980-0845 (Japan); Korsholm, S. B.; Meo, F.; Nielsen, S. K.; Salewski, M.; Stejner, M. [Association EURATOM-Risoe DTU, P.O. Box 49, DK-4000 Roskilde (Denmark)

    2010-10-15T23:59:59.000Z

    Collective Thomson scattering (CTS) system has been constructed at LHD making use of the high power electron cyclotron resonance heating (ECRH) system in Large Helical Device (LHD). The necessary features for CTS, high power probing beams and receiving beams, both with well defined Gaussian profile and with the fine controllability, are endowed in the ECRH system. The 32 channel radiometer with sharp notch filter at the front end is attached to the ECRH system transmission line as a CTS receiver. The validation of the CTS signal is performed by scanning the scattering volume. A new method to separate the CTS signal from background electron cyclotron emission is developed and applied to derive the bulk and high energy ion components for several combinations of neutral beam heated plasmas.

  12. Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions

    SciTech Connect (OSTI)

    Mori, Warren, B.

    2012-12-01T23:59:59.000Z

    We present results from the grant entitled, ���¢��������Continuation of full-scale three-dimensional numerical experiments on high-intensity particle and laser beam-matter interactions.���¢������� The research significantly advanced the understanding of basic high-energy density science (HEDS) on ultra intense laser and particle beam plasma interactions. This advancement in understanding was then used to to aid in the quest to make 1 GeV to 500 GeV plasma based accelerator stages. The work blended basic research with three-dimensions fully nonlinear and fully kinetic simulations including full-scale modeling of ongoing or planned experiments. The primary tool was three-dimensional particle-in-cell simulations. The simulations provided a test bed for theoretical ideas and models as well as a method to guide experiments. The research also included careful benchmarking of codes against experiment. High-fidelity full-scale modeling provided a means to extrapolate parameters into regimes that were not accessible to current or near term experiments, thereby allowing concepts to be tested with confidence before tens to hundreds of millions of dollars were spent building facilities. The research allowed the development of a hierarchy of PIC codes and diagnostics that is one of the most advanced in the world.

  13. Emission Spectroscopy of Highly Charged Ions in Plasma of an Electron Beam Ion Trap

    SciTech Connect (OSTI)

    Draganic, I. [Vinca Institute of Nuclear Sciences, P.O. Box 522, 11001 Belgrade (Serbia and Montenegro); Max-Planck Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Crespo Lopez-Urrutia, J.R.; Soria Orts, R.; Ullrich, J. [Max-Planck Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); DuBois, R. [University of Missouri-Rolla, Physics Building, Rolla, MO 63409-0640 (United States); Shevelko, V. [Lebedev Physical Institute, Russian Academy of Science, 117924 Moscow (Russian Federation); Fritzsche, S. [Department of Physics, University of Kassel, Heinrich-Plett-St. 40, D-34132 Kassel (Germany); Zou, Y. [Applied Ion Beam Physics Lab, Fudan University, Shanghai 200433 (China)

    2004-12-01T23:59:59.000Z

    The results of experimental study of magnetic dipole (M1) transitions in highly charged ions of argon (Ar9+, Ar10+, Ar13+ and Ar14+) and krypton (Kr18+ and Kr22+) are presented. The forbidden transitions of the highly charged ions in the visible and near UV range of the photon emission spectra have been measured with accuracy better than 1 ppm. Our measurements for the 'coronal lines' are the most accurate yet reported using an EBIT as a spectroscopic source of highly charged ions. These precise wavelength determinations provide a useful test and challenge for atomic structure calculations of many-electron systems.

  14. Issues concerning high current lower energy electron beams required for ion cooling between EBIS LINAC and booster

    SciTech Connect (OSTI)

    Hershcovitch,A.

    2009-03-01T23:59:59.000Z

    Some issues, regarding a low energy high current electron beam that will be needed for electron beam cooling to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster, are examined. Options for propagating such an electron beam, as well as the effect of neutralizing background plasma on electron and ion beam parameters are calculated. Computations and some experimental data indicate that none of these issues is a show stopper.

  15. Energy distribution of nonequilibrium electrons and optical phonons in GaAs under band-to-band pumping by intense short pulses of light

    SciTech Connect (OSTI)

    Altybaev, G. S.; Kumekov, S. E., E-mail: skumekov@mail.ru; Mahmudov, A. A. [Satpaev Kazakh National Technical University (Kazakhstan)

    2009-03-15T23:59:59.000Z

    Deviation from the Fermi distribution of nonequilibrium electrons and distribution of 'hot' optical phonons in GaAs under band-to-band pumping by picosecond pulses of light are calculated.

  16. Overview Of Control System For Jefferson Lab`s High Power Free Electron Laser

    SciTech Connect (OSTI)

    Hofler, A. S.; Grippo, A. C.; Keesee, M. S.; Song, J.

    1997-12-31T23:59:59.000Z

    In this paper the current plans for the control system for Thomas Jefferson National Accelerator Facility`s (Jefferson Lab`s) Infrared Free Electron Laser (FEL) are presented. The goals for the FEL control system are fourfold: (1) to use EPICS and EPICS compatible tools, (2) to use VME and Industry Pack (IPs) interfaces for FEL specific devices such as controls and diagnostics for the drive laser, high power optics, photocathode gun and electron-beam diagnostics, (3) to migrate Continuous Electron Beam Accelerator Facility (CEBAF) technologies to VME when possible, and (4) to use CAMAC solutions for systems that duplicate CEBAF technologies such as RF linacs and DC magnets. This paper will describe the software developed for FEL specific devices and provide an overview of the FEL control system.

  17. Intensity-modulated radiotherapy in patients with locally advanced rectal cancer reduces volume of bowel treated to high dose levels

    SciTech Connect (OSTI)

    Urbano, M. Teresa Guerrero [Department of Clinical Oncology, Royal Marsden NHS Trust, Sutton, Surrey (United Kingdom); Henrys, Anthony J. [Department of Clinical Oncology, Royal Marsden NHS Trust, Sutton, Surrey (United Kingdom); Adams, Elisabeth J. [Department of Clinical Oncology, Royal Marsden NHS Trust, Sutton, Surrey (United Kingdom); Norman, Andrew R. [Department of Clinical Oncology, Royal Marsden NHS Trust, Sutton, Surrey (United Kingdom); Bedford, James L. [Department of Clinical Oncology, Royal Marsden NHS Trust, Sutton, Surrey (United Kingdom); Harrington, Kevin J. [Department of Clinical Oncology, Royal Marsden NHS Trust, Sutton, Surrey (United Kingdom); Nutting, Christopher M. [Department of Clinical Oncology, Royal Marsden NHS Trust, Sutton, Surrey (United Kingdom); Dearnaley, David P. [Department of Clinical Oncology, Royal Marsden NHS Trust, Sutton, Surrey (United Kingdom); Tait, Diana M. [Department of Clinical Oncology, Royal Marsden NHS Trust, Sutton, Surrey (United Kingdom)]. E-mail: jenny.pearson@rmh.nthames.nhs.uk

    2006-07-01T23:59:59.000Z

    Purpose: To investigate the potential for intensity-modulated radiotherapy (IMRT) to spare the bowel in rectal tumors. Methods and Materials: The targets (pelvic nodal and rectal volumes), bowel, and bladder were outlined in 5 patients. All had conventional, three-dimensional conformal RT and forward-planned multisegment three-field IMRT plans compared with inverse-planned simultaneous integrated boost nine-field equally spaced IMRT plans. Equally spaced seven-field and five-field and five-field, customized, segmented IMRT plans were also evaluated. Results: Ninety-five percent of the prescribed dose covered at least 95% of both planning target volumes using all but the conventional plan (mean primary and pelvic planning target volume receiving 95% of the prescribed dose was 32.8 {+-} 13.7 Gy and 23.7 {+-} 4.87 Gy, respectively), reflecting a significant lack of coverage. The three-field forward planned IMRT plans reduced the volume of bowel irradiated to 45 Gy and 50 Gy by 26% {+-} 16% and 42% {+-} 27% compared with three-dimensional conformal RT. Additional reductions to 69 {+-} 51 cm{sup 3} to 45 Gy and 20 {+-} 21 cm{sup 3} to 50 Gy were obtained with the nine-field equally spaced IMRT plans-64% {+-} 11% and 64% {+-} 20% reductions compared with three-dimensional conformal RT. Reducing the number of beams and customizing the angles for the five-field equally spaced IMRT plan did not significantly reduce bowel sparing. Conclusion: The bowel volume irradiated to 45 Gy and 50 Gy was significantly reduced with IMRT, which could potentially lead to less bowel toxicity. Reducing the number of beams did not reduce bowel sparing and the five-field customized segmented IMRT plan is a reasonable technique to be tested in clinical trials.

  18. ATLAS Tile Calorimeter Readout Electronics Upgrade Program for the High Luminosity LHC

    E-Print Network [OSTI]

    A. S. Cerqueira

    2013-05-03T23:59:59.000Z

    The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the most central region of the ATLAS experiment at LHC. The TileCal readout consists of about 10000 channels. The ATLAS upgrade program is divided in three phases: The Phase~0 occurs during 2013-2014, Phase~1 during 2018-1019 and finally Phase~2, which is foreseen for 2022-2023, whereafter the peak luminosity will reach 5-7 x 10$^{34}$ cm$^2$s$^{-1}$ (HL-LHC). The main TileCal upgrade is focused on the Phase~2 period. The upgrade aims at replacing the majority of the on- and off-detector electronics so that all calorimeter signals are directly digitized and sent to the off-detector electronics in the counting room. All new electronics must be able to cope with the increased radiation levels. An ambitious upgrade development program is pursued to study different electronics options. Three options are presently being investigated for the front-end electronic upgrade. The first option is an improved version of the present system built using commercial components, the second alternative is based on the development of a dedicated ASIC (Application Specific Integrated Circuit) and the third is the development of a new version of the QIE (Charge Integrator and Encoder) based on the one developed for Fermilab. All three options will use the same readout and control system using high speed (up to 40 Gb/s) links for communication and clock synchronization. For the off-detector electronics a new back-end architecture is being developed. A demonstrator prototype read-out for a slice of the calorimeter with most of the new electronics, but still compatible with the present system, is planned to be inserted in ATLAS already in mid 2014 (at the end of the Phase~0 upgrade).

  19. HIGH-CURRENT COLD CATHODE FIELD EMISSION ARRAY FOR ELECTRON LENS APPLICATION

    SciTech Connect (OSTI)

    Hirshfield, Jay L

    2012-12-28T23:59:59.000Z

    During Phase I, the following goals were achieved: (1) design and fabrication of a novel, nano-dimensional CNT field emitter assembly for high current density application, with high durability; (2) fabrication of a ceramic based micro channel plate (MCP) and characterization of its secondary electron emission; and (3) characterizing the CNT/MCP cathode for high field emission and durability. As a result of these achievements, a relatively high current density of ~ 1.2 A/cm2 from a CNT cathode and single channel MCP were measured. The emission current was also extremely stable with a peak-to-peak variation of only 1.8%. The emission current could be further enhanced to meet requirements for electron lens applications by increasing the number of MCP channels. A calculation for maximum possible current density with a 1200 channel/cm2 MCP, placed over a cathode with 1200 uniformly functioning CNTs, would be ~1.46 kA/cm2, neglecting space charge limitations. Clearly this level of emission is far greater than what is needed for the electron lens application, but it does offer a highly comforting margin to account for sub-standard emitters and/or to allow the lesser challenge of building a cathode with fewer channels/cm2. A satisfactory goal for the electron lens application would be a controllable emission of 2-4 mA per channel in an ensemble of 800-1200 uniformly-functioning channels/cm2, and a cathode with overall area of about 1 cm2.

  20. A compact transport and charge model for GaN-based high electron mobility transistors for RF applications

    E-Print Network [OSTI]

    Radhakrishna, Ujwal

    2013-01-01T23:59:59.000Z

    Gallium Nitride (GaN)-based high electron mobility transistors (HEMTs) are rapidly emerging as front-runners in high-power mm-wave circuit applications. For circuit design with current devices and to allow sensible future ...

  1. Space-charge effects in ultra-high current electron bunches generated by laser-plasma accelerators

    E-Print Network [OSTI]

    Grinner, F. J.

    2009-01-01T23:59:59.000Z

    regime of laser-plasma-accelerated ultra-compact electronin ultra-high current electron bunches generated by laser-by laser-plasma accelerators due to their ultra-high peak

  2. Design and testing of an electron cyclotron resonance heating ion source for use in high field compact superconducting cyclotrons

    E-Print Network [OSTI]

    Artz, Mark E

    2012-01-01T23:59:59.000Z

    The main goal of this project is to evaluate the feasibility of axial injection of a high brightness beam from an Electron Cyclotron Resonance ion source into a high magnetic field cyclotron. Axial injection from an ion ...

  3. The uses of electron beam ion traps in the study of highly charged ions

    SciTech Connect (OSTI)

    Knapp, D.

    1994-11-02T23:59:59.000Z

    The Electron Beam Ion Trap (EBIT) is a relatively new tool for the study of highly charged ions. Its development has led to a variety of new experimental opportunities; measurements have been performed with EBITs using techniques impossible with conventional ion sources or storage rings. In this paper, I will highlight the various experimental techniques we have developed and the results we have obtained using the EBIT and higher-energy Super-EBIT built at the Lawrence Livermore National Laboratory. The EBIT employs a high-current-density electron beam to trap, ionize, and excite a population of ions. The ions can be studied in situ or extracted from the trap for external experiments. The trapped ions form an ionization-state equilibrium determined by the relative ionization and recombination rates. Ions of several different elements may simultaneously be present in the trap. The ions are nearly at rest, and, for most systems, all in their ground-state configurations. The electron-ion interaction energy has a narrow distribution and can be varied over a wide range. We have used the EBIT devices for the measurement of electron-ion interactions, ion structure, ion-surface interactions, and the behavior of low-density plasmas.

  4. Heavy flavor measurements using high-pt electrons in the ALICE EMCal

    E-Print Network [OSTI]

    Mark Heinz

    2010-06-07T23:59:59.000Z

    Heavy flavor hadrons, i.e. those containing charm and bottom quarks, will be abundantly produced at the LHC and are important probes of the Quark-Gluon Plasma (QGP). Of particular interest is the investigation of parton energy loss in the medium. Using heavy flavor jets we will have a pure sample of quark jets with which to study the color-charge effects on energy loss. In addition, studies of bottom production in p+p collision at LHC energies will be utilized to further constrain the current parameters used by NLO and FONLL calculations. The talk will focus on the very high-pt electron particle identi?cation using the EMCal detector. We present the electron reconstruction and measurements which can be achieved with 1 nominal year of Pb-Pb running at 5.5 TeV. We then estimate the rate of non-photonic electrons and present systematic and statistical error bars. Finally, we show preliminary results on B-jet tagging techniques in p+p which utilize jet-finding algorithms (FASTJET) in conjunction with displaced secondary vertices containing high-pt electrons.

  5. High-temperature electron emission from diamond films Department of Mechanical Engineering, Vanderbilt University, Nashville, Tennessee 37235

    E-Print Network [OSTI]

    Walker, D. Greg

    This work examines electron field-emission characteristics of polycrystalline diamond films at elevated in applications where high temperatures exist. Nitrogen-doped polycrystalline diamond films were grown by plasmaHigh-temperature electron emission from diamond films S. H. Shin Department of Mechanical

  6. THE ERL HIGH-ENERGY COOLER FOR RHIC* I. Ben-Zvi** for the electron cooling team***,

    E-Print Network [OSTI]

    ]. The design evolved during the past 5 years. The present design will use classical (non-magnetized) electron presents many challenges to the design of the cooler. The cooling is slowed down by the high- energyTHE ERL HIGH-ENERGY COOLER FOR RHIC* I. Ben-Zvi** for the electron cooling team***, C-AD, BNL

  7. A new device that produces and collects multiple electrons per photon could yield inexpensive, high-efficiency

    E-Print Network [OSTI]

    A new device that produces and collects multiple electrons per photon could yield inexpensive, high electron-hole pair) per absorbed high-energy photon, and this device definitively demonstrates-efficiency photovoltaics. A new device developed through research at the National Renewable Energy Laboratory (NREL

  8. gEMpicker: A Highly Parallel GPU-Accelerated Particle Picking Tool for Cryo-Electron Microscopy

    E-Print Network [OSTI]

    Boyer, Edmond

    gEMpicker: A Highly Parallel GPU-Accelerated Particle Picking Tool for Cryo-Electron Microscopy Abstract Background: Picking images of particles in cryo-electron micrographs is an important step particle images. Thus, a computational bottleneck in reaching high resolution is the accurate and automatic

  9. Ion implantation in compound semiconductors for high-performance electronic devices

    SciTech Connect (OSTI)

    Zolper, J.C.; Baca, A.G.; Sherwin, M.E.; Klem, J.F.

    1996-05-01T23:59:59.000Z

    Advanced electronic devices based on compound semiconductors often make use of selective area ion implantation doping or isolation. The implantation processing becomes more complex as the device dimensions are reduced and more complex material systems are employed. The authors review several applications of ion implantation to high performance junction field effect transistors (JFETs) and heterostructure field effect transistors (HFETs) that are based on compound semiconductors, including: GaAs, AlGaAs, InGaP, and AlGaSb.

  10. High Throughput Ab initio Modeling of Charge Transport for Bio-Molecular-Electronics

    E-Print Network [OSTI]

    Bruque, Nicolas A.

    2009-01-01T23:59:59.000Z

    DNA-Based Molecular Electronics. vol. 725. New York: AIP,Heath, “Whence molecular electronics? ” Science, vol. 306,model,” J. Computational Electronics, vol. 6, no. 4, pp.

  11. Spatial distribution of structural degradation under high-power stress in AlGaN/GaN high electron mobility transistors

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    and high temperature, the latter being a result of de- vice self-heating. A complicating factor degradation of AlGaN/GaN high electron mobility transistors was investigated under high-power electrical electrical degradation that was mostly driven by an electric field across the AlGaN barrier. Under high

  12. Electronic Systems for Radiation Detection in Space and High Energy Physics Applications

    E-Print Network [OSTI]

    Valerio, Pierpaolo; Ballabriga, Rafael

    This Ph.D. thesis focuses on the analysis and development of novel solution for electronics system for radiation detector, especially suited for space and high energy physics applications. The many blocks of a readout system were studied to develop complete systems, investigating where the performances can be improved over state of the art technologies. Two different architectures, suitable for different applications, were studied: Fractional Packet Counting, for High Dynamic Range (HDR) integrating imagers and CLICpix, an example of high-accuracy hybrid photon counting detector. The main specifications of the two systems were anayzed and solutions were proposed and implemented to meet them. A CLICpix prototype has been designed, fabricated using a commercial 65 nm CMOS technology and tested (characterization is still ongoing). The technology used for the prototype has also been characterized and validated for High Energy Physics (HEP) use and radiation hard design.

  13. Microstructure of highly strained BiFeO{sub 3} thin films: Transmission electron microscopy and electron-energy loss spectroscopy studies

    SciTech Connect (OSTI)

    Heon Kim, Young, E-mail: young.h.kim@kriss.re.kr [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Germany); Korea Research Institute of Standards and Science (KRISS), Daejeon 305-340 (Korea, Republic of); Bhatnagar, Akash; Pippel, Eckhard; Hesse, Dietrich [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Germany); Alexe, Marin [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Germany); University of Warwick, Coventry CV4 7AL, West Midlands (United Kingdom)

    2014-01-28T23:59:59.000Z

    Microstructure and electronic structure of highly strained bismuth ferrite (BiFeO{sub 3}) thin films grown on lanthanum aluminate substrates are studied using high-resolution transmission and scanning transmission electron microscopies and electron energy loss spectroscopy (EELS). Monoclinic and tetragonal phases were observed in films grown at different temperatures, and a mix of both phases was detected in a film grown at intermediate temperature. In this film, a smooth transition of the microstructure was found between the monoclinic and the tetragonal phases. A considerable increase in the c-axis parameters was observed in both phases compared with the rhombohedral bulk phase. The off-center displacement of iron (Fe) ions was increased in the monoclinic phase as compared with the tetragonal phase. EEL spectra show different electronic structures in the monoclinic and the tetragonal phases. These experimental observations are well consistent with the results of theoretical first-principle calculations performed.

  14. Manufacturing capabilities of high power electron beam furnaces for melting ignots to 40 tons in weight

    SciTech Connect (OSTI)

    Boiko, Ju.P.; Braim, V.P.; Kormitch, A.T.; Zorin, G.V.; Kostenuk, Ju.V.; Nikitin, V.S.; Pokrovsky, S.V.

    1994-12-31T23:59:59.000Z

    A tendency to using special technologies of melting steels and alloys to get large ingots free of macrodefects and shrinking shells used to provide defectless products, ensuring an increase of ingot-to-product yield is well known. The electron beam furnace process improves the economical efficiency of production of large ingots, slabs for rolling mills, where high quality of special purpose steels and alloys is required. Metals, made by means of electron beam melting can be used for power, nuclear and chemical machine-buildings, aircraft and automotive, instrument and bearing productions, injection moulds and moulds for cold rollings, magnetic and titanium alloys, ship shafts, propellers and high speed power turbine parts. Melting technologies, which is one of the most important stages in production of steels and alloys, predetermines a required quality of metals and alloys to get the following characteristics of remelted metals: impact strength; isotropy of properties in central and surface zones of ingots; fatigue strength and resistance under mechanical and heat loads; corrosion resistance to attack by aggressive media; and polishing properties. The furnace is equipped with five electron beam guns, type EH-1200/50 and pumps for pumping out cavities of technological equipments: melting and ingot chambers, charging devices.

  15. P-doping-free III-nitride high electron mobility light-emitting diodes and transistors

    SciTech Connect (OSTI)

    Li, Baikui; Tang, Xi; Chen, Kevin J., E-mail: eekjchen@ust.hk [Department of Electronic and Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Wang, Jiannong [Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

    2014-07-21T23:59:59.000Z

    We report that a simple metal-AlGaN/GaN Schottky diode is capable of producing GaN band-edge ultraviolet emission at 3.4?eV at a small forward bias larger than ?2?V at room temperature. Based on the surface states distribution of AlGaN, a mature impact-ionization-induced Fermi-level de-pinning model is proposed to explain the underlying mechanism of the electroluminescence (EL) process. By experimenting with different Schottky metals, Ni/Au and Pt/Au, we demonstrated that this EL phenomenon is a “universal” property of metal-AlGaN/GaN Schottky diodes. Since this light-emitting Schottky diode shares the same active structure and fabrication processes as the AlGaN/GaN high electron mobility transistors, straight-forward and seamless integration of photonic and electronic functional devices has been demonstrated on doping-free III-nitride heterostructures. Using a semitransparent Schottky drain electrode, an AlGaN/GaN high electron mobility light-emitting transistor is demonstrated.

  16. Absolute intensity calibration of flat-field space-resolved extreme ultraviolet spectrometer using radial profiles of visible and extreme ultraviolet bremsstrahlung continuum emitted from high-density plasmas in Large Helical Device

    SciTech Connect (OSTI)

    Dong Chunfeng; Wang Erhui [Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Gifu (Japan); Morita, Shigeru; Goto, Motoshi [Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292, Gifu (Japan); National Institute for Fusion Science, Toki 509-5292, Gifu (Japan)

    2011-11-15T23:59:59.000Z

    A precise absolute intensity calibration of a flat-field space-resolved extreme ultraviolet (EUV) spectrometer working in wavelength range of 60-400 A is carried out using a new calibration technique based on radial profile measurement of the bremsstrahlung continuum in Large Helical Device. A peaked vertical profile of the EUV bremsstrahlung continuum has been successfully observed in high-density plasmas (n{sub e}{>=} 10{sup 14} cm{sup -3}) with hydrogen ice pellet injection. The absolute calibration can be done by comparing the EUV bremsstrahlung profile with the visible bremsstrahlung profile of which the absolute value has been already calibrated using a standard lamp. The line-integrated profile of measured visible bremsstrahlung continuum is firstly converted into the local emissivity profile by considering a magnetic surface distortion due to the plasma pressure, and the local emissivity profile of EUV bremsstrahlung is secondly calculated by taking into account the electron temperature profile and free-free gaunt factor. The line-integrated profile of the EUV bremsstrahlung continuum is finally calculated from the local emissivity profile in order to compare with measured EUV bremsstrahlung profile. The absolute intensity calibration can be done by comparing measured and calculated EUV bremsstrahlung profiles. The calibration factor is thus obtained as a function of wavelength with excellent accuracy. It is also found in the profile analysis that the grating reflectivity of EUV emissions is constant along the direction perpendicular to the wavelength dispersion. Uncertainties on the calibration factor determined with the present method are discussed including charge-coupled device operation modes.

  17. Device and method for relativistic electron beam heating of a high-density plasma to drive fast liners

    DOE Patents [OSTI]

    Thode, Lester E. (Los Alamos, NM)

    1981-01-01T23:59:59.000Z

    A device and method for relativistic electron beam heating of a high-density plasma in a small localized region. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises DT, DD, hydrogen boron or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target gas is ionized prior to application of the electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy and momentum into a small localized region of the high-density plasma target. Fast liners disposed in the high-density target plasma are explosively or ablatively driven to implosion by a heated annular plasma surrounding the fast liner which is generated by an annular relativistic electron beam. An azimuthal magnetic field produced by axial current flow in the annular plasma, causes the energy in the heated annular plasma to converge on the fast liner.

  18. Inner-Shell Multiple Ionization of Polyatomic Molecules With an Intense X-Ray Free-Electron Laser Studied By Coincident Ion Momentum Imaging

    SciTech Connect (OSTI)

    Erk, B. [Max Planck Advanced Study Group and Deutsches Elektronen-Synchrotron, Hamburg (Germany); Max Planck Inst. for Nuclear Physics, Heidelberg (Germany); Rolles, D. [Max Planck Advanced Study Group and Deutsches Elektronen-Synchrotron, Hamburg (Germany); Max Planck Inst. for Medical Rearch, Heidelburg (Germany); Foucar, L. [Max Planck Society, Hamburg (Germany); Max Planck Inst. for Medical Rearch, Heidelburg (Germany); Rudek, B. [Max Planck Advanced Study Group and Deutsches Elektronen-Synchrotron, Hamburg (Germany); Max Planck Inst. for Nuclear Physics, Heidelberg (Germany); Epp, S. W. [Max Planck Society, Hamburg (Germany). Max Planck Inst. for Nuclear Physics; Max Planck Inst. for Nuclear Physics, Heidelberg (Germany); Cryle, M. [Max Planck Inst. for Medical Rearch, Heidelburg (Germany); Bostedt, C. [SLAC National Accelerator Lab., Menlo Park, CA (United States). Linac Coherent Light Source; Schorb, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States). Linac Coherent Light Source; Technical Univ. Berlin (Germany). Inst. for Optic and Atomic Physics; Bozek, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States). Linac Coherent Light Source; Rouzee, A. [Max Born Inst., Berlin (Germany); Hundertmark, A. [Max Born Inst., Berlin (Germany); Marchenko, T. [Laboratory of Chemical Physics, Paris (France); Simon, M. [Laboratory of Chemical Physics, Paris (France); Filsinger, F. [Fritz Haber Inst. for Max Planck Gesellschaft, Berlin (Germany); Christensen, L. [Aarhus Univ. (Denmark). Dept. of Physics and Astronomy; De, S. [Aarhus Univ. (Denmark). Dept. of Chemistry; Saha Inst. of Nuclear Physics, Kolkata (India); Trippel, S. [Center for Free-Electron Laser Science (CFEL), Hamburg (Germany); Küpper, J. [Center for Free-Electron Laser Science (CFEL) and Univ. of Hamburg, Hamburg (Germany). Dept. of Physics, Center for Ultrafast Imaging; Stapelfeldt, H. [Aarhus Univ. (Denmark). Dept. of Chemistry; Wada, S. [SLAC National Accelerator Lab., Menlo Park, CA (United States). Linac Coherent Light Source; Hiroshima Univ., Higashi-Hiroshima (Japan), Dept. of Physical Science; Ueda, K. [Tohoku Univ., Sendai (Japan). IMRAM; Swiggers, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States). Linac Coherent Light Source; Messerschmidt, M. [SLAC National Accelerator Lab., Menlo Park, CA (United States). Linac Coherent Light Source; Schröter, C. D. [Max Planck Inst. for Nuclear Physics, Heidelberg (Germany); Moshammer, R. [Max Planck Society, Hamburg (Germany). Max Planck Inst. for Nuclear Physics; Max Planck Inst. for Nuclear Physics, Heidelberg (Germany); Schlichting, I. [Max Planck Society, Hamburg (Germany); Max Planck Inst. for Medical Rearch, Heidelburg (Germany); Ullrich, J. [Max Planck Society, Hamburg (Germany). Max Planck Inst. for Nuclear Physics; Max Planck Inst. for Nuclear Physics, Heidelberg (Germany); National Institute for Physics and Technology, Braunschweig (Germany); Rudenko, A. [Max Planck Society, Hamburg (Germany). Max Planck Inst. for Nuclear Physics; Max Planck Inst. for Nuclear Physics, Heidelberg (Germany); Kansas State Univ., Manhattan, KS (United States). Dept. of Physics

    2013-08-28T23:59:59.000Z

    The ionization and fragmentation of two selenium containing hydrocarbon molecules, methylselenol (CH3SeH) and ethylselenol (C2H5SeH), by intense (>1017 W cm-2 ) 5 fs x-ray pulses with photon energies of 1.7 and 2 keV has been studied by means of coincident ion momentum spectroscopy. Measuring charge states and ion kinetic energies, we find signatures of charge redistribution within the molecular environment. Furthermore, by analyzing fragment ion angular correlations, we can determine the laboratory-frame orientation of individual molecules and thus investigate the fragmentation dynamics in the molecular frame. This allows distinguishing protons originating from different molecular sites along with identifying the reaction channels that lead to their emission.

  19. Inner-Shell Multiple Ionization of Polyatomic Molecules With an Intense X-Ray Free-Electron Laser Studied By Coincident Ion Momentum Imaging

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

    Erk, B.; Rolles, D.; Foucar, L.; Rudek, B.; Epp, S. W.; Cryle, M.; Bostedt, C.; Schorb, S.; Bozek, J.; Rouzee, A.; et al

    2013-08-28T23:59:59.000Z

    The ionization and fragmentation of two selenium containing hydrocarbon molecules, methylselenol (CH3SeH) and ethylselenol (C2H5SeH), by intense (>1017 W cm-2 ) 5 fs x-ray pulses with photon energies of 1.7 and 2 keV has been studied by means of coincident ion momentum spectroscopy. Measuring charge states and ion kinetic energies, we find signatures of charge redistribution within the molecular environment. Furthermore, by analyzing fragment ion angular correlations, we can determine the laboratory-frame orientation of individual molecules and thus investigate the fragmentation dynamics in the molecular frame. This allows distinguishing protons originating from different molecular sites along with identifying the reactionmore »channels that lead to their emission.« less

  20. Electronic imaging system and technique

    DOE Patents [OSTI]

    Bolstad, J.O.

    1984-06-12T23:59:59.000Z

    A method and system for viewing objects obscurred by intense plasmas or flames (such as a welding arc) includes a pulsed light source to illuminate the object, the peak brightness of the light reflected from the object being greater than the brightness of the intense plasma or flame; an electronic image sensor for detecting a pulsed image of the illuminated object, the sensor being operated as a high-speed shutter; and electronic means for synchronizing the shutter operation with the pulsed light source.

  1. Predicted Bremsstrahlung generation by energetic electron beams

    SciTech Connect (OSTI)

    Faehl, R.J.; Snell, C.M.; Keinigs, R.K.

    1991-01-01T23:59:59.000Z

    The CYLTRAN photon/electron Monte Carlo code has been employed to predict Bremsstrahlung generation by monoenergetic electron beams from 10 to 1000 MeV. The forward-directed Bremsstrahlung intensity is investigated as a function of beam energy converter thickness, and material. At high energies, the forward extraction efficiency is maximized by using converters that are about 0.1-electron ranges thick. The largest intensities are attained with low-Z converter materials such as beryllium. Because the Bremsstrahlung radiation is strongly forward-directed, low divergence of the incident electron beam is crucial. Under deal conditions, a 1000-MeV beam can produce intensities up to 10{sup 8} MeV per steradian, per incident electron. 9 refs., 32 figs., 12 tabs.

  2. Direct first-principles simulation of a high-performance electron emitter: Lithium-oxide-coated diamond surface

    SciTech Connect (OSTI)

    Miyamoto, Yoshiyuki, E-mail: yoshi-miyamoto@aist.go.jp; Miyazaki, Takehide [Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); Takeuchi, Daisuke; Yamasaki, Satoshi [Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan); JST, ALCA, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan)

    2014-09-28T23:59:59.000Z

    We examined the field emission properties of lithium(Li)/oxygen(O)-co-terminated diamond (001) surface [C(001)-LiO] through real-time electron dynamics simulation under an applied field. The current emitted from this surface was found to be more than four-fold that emitted by an H-terminated (001) surface, the latter being a typical negative electron affinity system. This high performance is attributed to the Li layer, which bends the potential wall of O-induced electron pockets down in the direction of vacuum, thus facilitating electron emission. Detailed analysis of the emitted electrons and the profile of the self-consistent potential elucidated that the role of O atoms changes from an electron barrier on OH-terminated diamond surfaces to an outlet for electron emission on C(001)-LiO.

  3. 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.

  4. Solar wind suprathermal electron Stahl widths across high-speed stream structures

    SciTech Connect (OSTI)

    Skoug, Ruth M [Los Alamos National Laboratory; Steinberg, John T [Los Alamos National Laboratory; Goodrich, Katherine A [Los Alamos National Laboratory; Anderson, Brett R [DARTMUTH UNIV.

    2011-01-03T23:59:59.000Z

    Suprathermal electrons (100-1500 eV) observed in the solar wind typically show a strahl distribution, that is, a beam directed away from the Sun along the magnetic field direction. The strahl width observed at 1 AU is highly variable, ranging from 10-70 degrees. The obsenred finite width of the strahl results from the competition between beam focusing as the interplanetary magnetic field strength drops with distance from the Sun, and pitch-angle scattering as the beam interacts with the solar wind plasma in transit from the sun. Here we examine strahl width, observed with ACE SWEPAM across high-speed stream structures to investigate variations in electron scattering as a function of local plasma characteristics. We find that narrow strahls (less than 20 degrees wide), indicating reduced scattering, are observed within high-speed streams. Narrow strahls are also observed in both very low temperature solar wind, in association with ICMEs. Case studies of high-speed streams typically show the strahl narrowing at the leading edge of the stream. In some cases, the strahl narrows at the reverse shock or pressure wave, in other cases at the stream interface. The narrowing can either occur discontinuously or gradually over a period of hours. Within the high-speed wind, the strahl remains narrow for a period of hours to days, and then gradually broadens. The strahl width is roughly constant at all energies across these structures. For some fraction of high-speed streams, counterstreaming is associated with passage of the corotating interaction region. In these cases, we find the widths of the two counterstreaming beams frequently differ by more than 40 degrees. This dramatic difference in strahl width contrasts with observations in the solar wind as a whole, in which counterstreaming strahls typically differ in width by less than 20 degrees.

  5. High quality single shot ultrafast MeV electron diffraction from a photocathode radio-frequency gun

    SciTech Connect (OSTI)

    Fu, Feichao; Liu, Shengguang; Zhu, Pengfei; Xiang, Dao, E-mail: dxiang@sjtu.edu.cn; Zhang, Jie, E-mail: jzhang1@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Cao, Jianming [Department of Physics and National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310 (United States)

    2014-08-15T23:59:59.000Z

    A compact ultrafast electron diffractometer, consisting of an s-band 1.6 cell photocathode radio-frequency gun, a multi-function changeable sample chamber, and a sensitive relativistic electron detector, was built at Shanghai Jiao Tong University. High-quality single-shot transmission electron diffraction patterns have been recorded by scattering 2.5?MeV electrons off single crystalline gold and polycrystalline aluminum samples. The high quality diffraction pattern indicates an excellent spatial resolution, with the ratio of the diffraction ring radius over the ring rms width beyond 10. The electron pulse width is estimated to be about 300 fs. The high temporal and spatial resolution may open new opportunities in various areas of sciences.

  6. Reduction of Edge Localized Mode Intensity on DIII-D by On-demand triggering with High Frequency Pellet Injection and Implications for ITER

    SciTech Connect (OSTI)

    Baylor, Larry R [ORNL; Commaux, Nicolas JC [ORNL; Jernigan, T. C. [Oak Ridge National Laboratory (ORNL); Meitner, Steven J [ORNL; Combs, Stephen Kirk [ORNL; Isler, Ralph C [ORNL; Unterberg, Ezekial A [ORNL; Brooks, N. H. [General Atomics, San Diego; Evans, T.E. [General Atomics, San Diego; Leonard, A. W. [General Atomics; Osborne, T. H. [General Atomics; Parks, P. B. [General Atomics; Snyder, P. B. [General Atomics; Strait, E. J. [General Atomics; Fenstermacher, M. E. [Lawrence Livermore National Laboratory (LLNL); Lasnier, C. J. [Lawrence Livermore National Laboratory (LLNL); Moyer, R.A. [University of California, San Diego; Loarte, A. [ITER Organization, Cadarache, France; Huijsmans, G.T.A. [ITER Organization, Saint Paul Lez Durance, France; Futantani, S. [ITER Organization, Saint Paul Lez Durance, France

    2013-01-01T23:59:59.000Z

    The injection of small deuterium pellets at high repetition rates up to 12 the natural edge localized mode (ELM) frequency has been used to trigger high-frequency ELMs in otherwise low natural ELM frequency H-mode deuterium discharges in the DIII-D tokamak [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)]. The resulting pellet-triggered ELMs result in up to 12 lower energy and particle fluxes to the divertor than the natural ELMs. The plasma global energy confinement and density are not strongly affected by the pellet perturbations. The plasma core impurity density is strongly reduced with the application of the pellets. These experiments were performed with pellets injected from the low field side pellet in plasmas designed to match the ITER baseline configuration in shape and normalized operation with input heating power just above the H-mode power threshold. Nonlinear MHD simulations of the injected pellets show that destabilization of ballooning modes by a local pressure perturbation is responsible for the pellet ELM triggering. This strongly reduced ELM intensity shows promise for exploitation in ITER to control ELM size while maintaining high plasma purity and performance.

  7. Reduction of edge localized mode intensity on DIII-D by on-demand triggering with high frequency pellet injection and implications for ITER

    SciTech Connect (OSTI)

    Baylor, L. R.; Commaux, N.; Jernigan, T. C.; Meitner, S. J.; Combs, S. K.; Isler, R. C.; Unterberg, E. A. [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, Tennessee 37830-6169 (United States)] [Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, Tennessee 37830-6169 (United States); Brooks, N. H.; Evans, T. E.; Leonard, A. W.; Osborne, T. H.; Parks, P. B.; Snyder, P. B.; Strait, E. J. [General Atomics, PO Box 85608, San Diego, California 92186-5608 (United States)] [General Atomics, PO Box 85608, San Diego, California 92186-5608 (United States); Fenstermacher, M. E.; Lasnier, C. J. [Lawrence Livermore National Laboratory, 700 East Ave, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, 700 East Ave, Livermore, California 94550 (United States); Moyer, R. A. [University of California San Diego, 9500 Gilman Dr., La Jolla, California 92093-0417 (United States)] [University of California San Diego, 9500 Gilman Dr., La Jolla, California 92093-0417 (United States); Loarte, A.; Huijsmans, G. T. A.; Futatani, S. [ITER Organization, Route de Vinon sur Verdon, 13115 St. Paul Lez Durance (France)] [ITER Organization, Route de Vinon sur Verdon, 13115 St. Paul Lez Durance (France)

    2013-08-15T23:59:59.000Z

    The injection of small deuterium pellets at high repetition rates up to 12× the natural edge localized mode (ELM) frequency has been used to trigger high-frequency ELMs in otherwise low natural ELM frequency H-mode deuterium discharges in the DIII-D tokamak [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)]. The resulting pellet-triggered ELMs result in up to 12× lower energy and particle fluxes to the divertor than the natural ELMs. The plasma global energy confinement and density are not strongly affected by the pellet perturbations. The plasma core impurity density is strongly reduced with the application of the pellets. These experiments were performed with pellets injected from the low field side pellet in plasmas designed to match the ITER baseline configuration in shape and normalized ? operation with input heating power just above the H-mode power threshold. Nonlinear MHD simulations of the injected pellets show that destabilization of ballooning modes by a local pressure perturbation is responsible for the pellet ELM triggering. This strongly reduced ELM intensity shows promise for exploitation in ITER to control ELM size while maintaining high plasma purity and performance.

  8. Reverse gate bias-induced degradation of AlGaN/GaN high electron mobility transistors

    E-Print Network [OSTI]

    Florida, University of

    , or temperature in- creases due to self-heating. For example, in the on-state stress condition, there may be strong self-heating of the HEMT and a high density of hot electrons in the channel, but accompanied and gate leakage, but should reduce contributions from hot electrons and self-heating.13

  9. High pressure and synchrotron radiation studies of solid state electronic instabilities. Final technial report, May 1, 1984--April 1987

    SciTech Connect (OSTI)

    Pifer, J.H.; Croft, M.C.

    1992-04-01T23:59:59.000Z

    This report discusses Eu and General Valence Instabilities; Ce Problem: L{sub 3} Spectroscopy Emphasis; Bulk Property Emphasis; Transition Metal Compound Electronic Structure; Electronic Structure-Phonon Coupling Studies; High Temperature Superconductivity and Oxide Materials; and Novel Materials Collaboration with Chemistry.

  10. Intensive Observation

    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 PowerCherries 82981-1cnHigh SchoolIn Other NewsSpin andInterimInvokingInspector XE 2013

  11. Magnetic lens apparatus for a low-voltage high-resolution electron microscope

    DOE Patents [OSTI]

    Crewe, Albert V. (Palos Park, IL)

    1996-01-01T23:59:59.000Z

    A lens apparatus in which a beam of charged particles of low accelerating voltage is brought to a focus by a magnetic field, the lens being situated behind the target position. The lens comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. The lens apparatus comprises the sole focusing lens for high-resolution imaging in a low-voltage scanning electron microscope.

  12. Dyakonov-perel electron spin relaxation in a highly degenerate wurtzite semiconductor

    SciTech Connect (OSTI)

    Rudolph, J.; Buß, J. H.; Hägele, D. [Arbeitsgruppe Spektroskopie der kondensierten Materie, Ruhr-Universität Bochum, Universitätsstraße 150, D-44780 Bochum (Germany); Semond, F. [Centre de Recherche sur l'Hétéro-Epitaxie et ses Applications, Centre National de la Recherche Scientifique, Sophia Antipolis, Valbonne (France)

    2013-12-04T23:59:59.000Z

    The doping density dependence of the electron spin lifetime in n-type bulk GaN is investigated up to the highly degenerate regime by time-resolved Kerr-rotation spectroscopy. We find a non-monotonic doping density dependence with maximum spin lifetimes at the onset of degeneracy. The reduction of spin lifetimes in the degenerate regime shows a weak ?{sub s}?n{sub D}{sup ?2/3} density dependence, in full agreement with Dyakonov-Perel theory.

  13. High-Sensitivity Two-Photon Spectroscopy in a Dark Optical Trap, based on Electron Shelving

    E-Print Network [OSTI]

    Khaykovich, B; Baluschev, S; Fathi, D; Davidson, N E

    1999-01-01T23:59:59.000Z

    We propose a new spectroscopic method for measuring weak transitions in cold and trapped atoms, which exploits the long interaction times and tight confinement offered by dark optical traps together with an electron shelving technique to achieve extremely high sensitivity. We demonstrate our scheme by measuring a 5S_{1/2}-> 5D_{5/2} two-photon transition in cold Rb atoms trapped in a new single-beam dark optical trap, using an extremely weak probe laser power of 25 micro-Watt. We were able to measure transitions with as small excitation rate as 0.09 sec^(-1).

  14. Magnetic lens apparatus for use in high-resolution scanning electron microscopes and lithographic processes

    DOE Patents [OSTI]

    Crewe, Albert V. (Dune Acres, IN)

    2000-01-01T23:59:59.000Z

    Disclosed are lens apparatus in which a beam of charged particlesis brought to a focus by means of a magnetic field, the lens being situated behind the target position. In illustrative embodiments, a lens apparatus is employed in a scanning electron microscopeas the sole lens for high-resolution focusing of an electron beam, and in particular, an electron beam having an accelerating voltage of from about 10 to about 30,000 V. In one embodiment, the lens apparatus comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. In other embodiments, the lens apparatus comprises a magnetic dipole or virtual magnetic monopole fabricated from a variety of materials, including permanent magnets, superconducting coils, and magnetizable spheres and needles contained within an energy-conducting coil. Multiple-array lens apparatus are also disclosed for simultaneous and/or consecutive imaging of multiple images on single or multiple specimens. The invention further provides apparatus, methods, and devices useful in focusing charged particle beams for lithographic processes.

  15. Development of a high-temperature oven for the 28 GHz electron cyclotron resonance ion source

    SciTech Connect (OSTI)

    Ohnishi, J., E-mail: ohnishi@riken.jp; Higurashi, Y.; Kidera, M.; Ozeki, K.; Nakagawa, T. [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan)] [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan)

    2014-02-15T23:59:59.000Z

    We have been developing the 28 GHz ECR ion source in order to accelerate high-intensity uranium beams at the RIKEN RI-beam Factory. Although we have generated U{sup 35+} beams by the sputtering method thus far, we began developing a high-temperature oven with the aim of increasing and stabilizing the beams. Because the oven method uses UO{sub 2}, a crucible must be heated to a temperature higher than 2000?°C to supply an appropriate amount of UO{sub 2} vapor to the ECR plasma. Our high-temperature oven uses a tungsten crucible joule-heated with DC current of approximately 450 A. Its inside dimensions are ?11 mm × 13.5 mm. Since the crucible is placed in a magnetic field of approximately 3 T, it is subject to a magnetic force of approximately 40 N. Therefore, we used ANSYS to carefully design the crucible, which was manufactured by machining a tungsten rod. We could raise the oven up to 1900?°C in the first off-line test. Subsequently, UO{sub 2} was loaded into the crucible, and the oven was installed in the 28 GHz ECR ion source and was tested. As a result, a U{sup 35+} beam current of 150 ?A was extracted successfully at a RF power of approximately 3 kW.

  16. Floating Refrigerant Loop Based on R-134a Refrigerant Cooling of High-Heat Flux Electronics

    SciTech Connect (OSTI)

    Lowe, K.T.

    2005-10-07T23:59:59.000Z

    The Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) have been developing technologies to address the thermal issues associated with hybrid vehicles. Removal of the heat generated from electrical losses in traction motors and their associated power electronics is essential for the reliable operation of motors and power electronics. As part of a larger thermal control project, which includes shrinking inverter size and direct cooling of electronics, ORNL has developed U.S. Patent No. 6,772,603 B2, ''Methods and Apparatus for Thermal Management of Vehicle Systems and Components'' [1], and patent pending, ''Floating Loop System for Cooling Integrated Motors and Inverters Using Hot Liquid Refrigerant'' [2]. The floating-loop system provides a large coefficient of performance (COP) for hybrid-drive component cooling. This loop (based on R-134a) is integrated with a vehicle's existing air-conditioning (AC) condenser, which dissipates waste heat to the ambient air. Because the temperature requirements for cooling of power electronics and electric machines are not as low as that required for passenger compartment air, this adjoining loop can operate on the high-pressure side of the existing AC system. This arrangement also allows the floating loop to run without the need for the compressor and only needs a small pump to move the liquid refrigerant. For the design to be viable, the loop must not adversely affect the existing system. The loop should also provide a high COP, a flat-temperature profile, and low-pressure drop. To date, the floating-loop test prototype has successfully removed 2 kW of heat load in a 9 kW automobile passenger AC system with and without the automotive AC system running. The COP for the tested floating-loop system ranges from 40-45, as compared to a typical AC system COP of about 2-4. The estimated required waste-heat load for future hybrid applications is 5.5 kW and the existing system could be easily scaleable for this larger load.

  17. Current collapse imaging of Schottky gate AlGaN/GaN high electron mobility transistors by electric field-induced optical second-harmonic generation measurement

    SciTech Connect (OSTI)

    Katsuno, Takashi, E-mail: e1417@mosk.tytlabs.co.jp; Ishikawa, Tsuyoshi; Ueda, Hiroyuki; Uesugi, Tsutomu [Toyota Central R and D Laboratories Inc., Nagakute, Aichi 480-1192 (Japan); Manaka, Takaaki; Iwamoto, Mitsumasa [Department of Physical Electronics, Tokyo Institute of Technology, Meguro, Tokyo 152-8552 (Japan)

    2014-06-23T23:59:59.000Z

    Two-dimensional current collapse imaging of a Schottky gate AlGaN/GaN high electron mobility transistor device was achieved by optical electric field-induced second-harmonic generation (EFISHG) measurements. EFISHG measurements can detect the electric field produced by carriers trapped in the on-state of the device, which leads to current collapse. Immediately after (e.g., 1, 100, or 800??s) the completion of drain-stress voltage (200?V) in the off-state, the second-harmonic (SH) signals appeared within 2??m from the gate edge on the drain electrode. The SH signal intensity became weak with time, which suggests that the trapped carriers are emitted from the trap sites. The SH signal location supports the well-known virtual gate model for current collapse.

  18. Electron attachment to C{sub 2} fluorocarbon radicals at high temperature

    SciTech Connect (OSTI)

    Shuman, Nicholas S.; Miller, Thomas M.; Viggiano, Albert A., E-mail: afrl.rvborgmailbox@kirtland.af.mil [Air Force Research Laboratory, Space Vehicle Directorate, Kirtland Air Force Base, New Mexico 87117 (United States)

    2013-11-14T23:59:59.000Z

    Thermal electron attachment to the radical species C{sub 2}F{sub 3} and C{sub 2}F{sub 5} has been studied over the temperature range 300–890 K using the Variable Electron and Neutral Density Attachment Mass Spectrometry technique. Both radicals exclusively undergo dissociative attachment to yield F{sup ?}. The rate constant for C{sub 2}F{sub 5} shows little dependence over the temperature range, remaining ?4 × 10{sup ?9}?cm{sup 3}?s{sup ?1}. The rate constant for C{sub 2}F{sub 3} attachment rises steeply with temperature from 3 × 10{sup ?11} cm{sup 3} s{sup ?1} at 300?K to 1 × 10{sup ?9} cm{sup 3} s{sup ?1} at 890 K. The behaviors of both species at high temperature are in agreement with extrapolations previously made from data below 600?K using a recently developed kinetic modeling approach. Measurements were also made on C{sub 2}F{sub 3}Br and C{sub 2}F{sub 5}Br (used in this work as precursors to the radicals) over the same temperature range, and, for C{sub 2}F{sub 5}Br as a function of electron temperature. The attachment rate constants to both species rise with temperature following Arrhenius behavior. The attachment rate constant to C{sub 2}F{sub 5}Br falls with increasing electron temperature, in agreement with the kinetic modeling. The current data fall in line with past predictions of the kinetic modeling approach, again showing the utility of this simplified approach.

  19. High-Pressure Thermodynamic Properties of f-electron Metals, Transition Metal Oxides, and Half-Metallic Magnets

    SciTech Connect (OSTI)

    Richard T. Scalettar; Warren E. Pickett

    2005-08-02T23:59:59.000Z

    This project involves research into the thermodynamic properties of f-electron metals, transition metal oxides, and half-metallic magnets at high pressure. These materials are ones in which the changing importance of electron-electron interactions as the distance between atoms is varied can tune the system through phase transitions from localized to delocalized electrons, from screened to unscreened magnetic moments, and from normal metal to one in which only a single spin specie can conduct. Three main thrusts are being pursued: (i) Mott transitions in transition metal oxides, (ii) magnetism in half-metallic compounds, and (iii) large volume-collapse transitions in f-band metals.

  20. On a mechanism of high-temperature superconductivity: Spin-electron acoustic wave as a mechanism for the Cooper pair formation

    E-Print Network [OSTI]

    Andreev, Pavel A; Kuz'menkov, L S

    2015-01-01T23:59:59.000Z

    We found a mechanism of the electron Cooper pair formation via the electron interaction by means of the spin-electron acoustic waves. This mechanism exists in metals with the rather high spin polarization like ferromagnetic and ferrimagnetic materials. The spin-electron acoustic wave mechanism gives the transition temperature 100 times larger than the transition temperature given by the electron-phonon interaction. Therefore, spin-electron acoustic waves give explanation for the high-temperature superconductivity. We find that the transition temperature has strong dependence on the electron concentration and the spin polarization of the electrons.

  1. Design Overview of a Highly Stable Infrared Free Electron Laser at LBL

    E-Print Network [OSTI]

    Kim, K.-J.

    2011-01-01T23:59:59.000Z

    Twelfth International Free Electron Laser Conference, Paris,Stable Infrared Free Electron Laser at LBL K. -J. Kim, M.Stable Infrared Free Electron Laser at LBL* K. -J. Kim, M.

  2. THE FREE ELECTRON LASER AS A POWER SOURCE FOR A HIGH-GRADIENT ACCELERATING STRUCTURE

    E-Print Network [OSTI]

    Sessler, A.M.

    2008-01-01T23:59:59.000Z

    18-23, 1982 THE FREE ELECTRON LASER AS A POWER SOURCE FOR AAC03-76SF00098 THE FREE ELECTRON LASER AS A POWER SOURCE FORVariable Parameter Free Electron Laser", to be pub 1 i shed

  3. Master-Oscillator-Power-Amplifier (MOPA) Laser Sources Used as Drive Lasers for Photoinjectors for High-Gain, Free Electron Lasers (FELs)

    E-Print Network [OSTI]

    Anlage, Steven

    for High-Gain, Free Electron Lasers (FELs) By David Leonard Demske Scholarly paper submitted In partial Milchberg #12;- 1 - Abstract The realization of extremely high gain, and high power in Free Electron Lasers laser arrangements to extract electron bunches from photocathodes. The performance of FELs depends

  4. High-Speed Real-Time Digital Emulation for Hardware-in-the-Loop Testing of Power Electronics: A New Paradigm in the Field of Electronic Design Automation (EDA) for Power Electronics Systems

    E-Print Network [OSTI]

    Kinsy, Michel A.

    This paper details the design and application of a new ultra-high speed real-time simulation for Hardware-in-the-Loop (HiL) testing and design of high-power power electronics systems. Our real-time hardware emulation for ...

  5. AlGaN/GaN High-Electron-Mobility Transistor Employing an Additional Gate for High-Voltage Switching Applications

    E-Print Network [OSTI]

    Seo, Kwang Seok

    AlGaN/GaN High-Electron-Mobility Transistor Employing an Additional Gate for High-Voltage Switching 16, 2004; accepted May 10, 2005; published September 8, 2005) We have proposed and fabricated an AlGaN/GaN: GaN, AlGaN, HEMT, switch 1. Introduction GaN has attracted attention for high-power and high

  6. Statistical analysis of the dynamics of secondary electrons in the flare of a high-voltage beam-type discharge

    SciTech Connect (OSTI)

    Demkin, V. P.; Mel'nichuk, S. V. [National Research Tomsk State University, 36, Lenin Ave., 634050 Tomsk (Russian Federation)

    2014-09-15T23:59:59.000Z

    In the present work, results of investigations into the dynamics of secondary electrons with helium atoms in the presence of the reverse electric field arising in the flare of a high-voltage pulsed beam-type discharge and leading to degradation of the primary electron beam are presented. The electric field in the discharge of this type at moderate pressures can reach several hundred V/cm and leads to considerable changes in the kinetics of secondary electrons created in the process of propagation of the electron beam generated in the accelerating gap with a grid anode. Moving in the accelerating electric field toward the anode, secondary electrons create the so-called compensating current to the anode. The character of electron motion and the compensating current itself are determined by the ratio of the field strength to the concentration of atoms (E/n). The energy and angular spectra of secondary electrons are calculated by the Monte Carlo method for different ratios E/n of the electric field strength to the helium atom concentration. The motion of secondary electrons with threshold energy is studied for inelastic collisions of helium atoms and differential analysis is carried out of the collisional processes causing energy losses of electrons in helium for different E/n values. The mechanism of creation and accumulation of slow electrons as a result of inelastic collisions of secondary electrons with helium atoms and selective population of metastable states of helium atoms is considered. It is demonstrated that in a wide range of E/n values the motion of secondary electrons in the beam-type discharge flare has the character of drift. At E/n values characteristic for the discharge of the given type, the drift velocity of these electrons is calculated and compared with the available experimental data.

  7. Generation of Alfven waves by high power pulse at the electron plasma frequency

    E-Print Network [OSTI]

    California at Los Angles, University of

    to a pulse of field aligned superthermal electrons. This electron current pulse then launches an Alfve´n wave with w wci. In space plasmas, there are many instances where pulses of field aligned superthermal-plasma interaction is the means of generating the electron pulse. Superthermal electron pulses, with duration

  8. High current, low emittance, steady state electron guns with plasma cathodes

    SciTech Connect (OSTI)

    Herschovitch, A. [Brookhaven National Laboratory, Upton, NY (United States)

    1995-12-31T23:59:59.000Z

    Major limitations of plasma cathodes have been overcome in an electron gun based on extraction of superthermal electrons with a low thermal spread. A grid is employed to select these electrons for extraction while retaining the bulk electrons in the discharge. Steady state extraction of electron beams corresponding to over 60% of the total arc discharge current has been observed. A perveance of over 280 microperv was reached with the extraction of 9A at 1KeV from a 6 mm aperture. Some of the characteristics of the electron gun described in this paper are very attractive for electron beam melting.

  9. Peculiarities of the Light Absorption and Emission by Free Electrons in Multivalley Semiconductors

    E-Print Network [OSTI]

    P. M. Tomchuk

    2008-11-18T23:59:59.000Z

    General expressions are obtained for the coefficient of light absorption by free carriers as well as the intensity of the spontaneous light emission by hot electrons in multivalley semiconductors. These expressions depend on the electron concentration and electron temperature in the individual valleys. An anisotropy of the dispersion law and electron scattering mechanisms is taken into account. Impurity-related and acoustic scattering mechanisms are analyzed. Polarization dependence of the spontaneous emission by hot electrons is found out. At unidirectional pressure applied or high irradiation intensities, the polarization dependence also appears in the coefficient of light absorption by free electrons.

  10. High-brightness electron beam evolution following laser-based cleaning of a photocathode

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

    Zhou, F.; Brachmann, A.; Decker, F-J.; Emma, P.; Gilevich, S.; Iverson, R.; Stefan, P.; Turner, J.

    2012-09-01T23:59:59.000Z

    Laser-based techniques have been widely used for cleaning metal photocathodes to increase quantum efficiency (QE). However, the impact of laser cleaning on cathode uniformity and thereby on electron beam quality are less understood. We are evaluating whether this technique can be applied to revive photocathodes used for high-brightness electron sources in advanced x-ray free-electron laser (FEL) facilities, such as the Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Laboratory. The laser-based cleaning was applied to two separate areas of the current LCLS photocathode on July 4 and July 26, 2011, respectively. The QE was increased by 8–10 times upon the laser cleaning. Since the cleaning, routine operation has exhibited a slow evolution of the QE improvement and comparatively rapid improvement of transverse emittance, with a factor of 3 QE enhancement over five months, and a significant emittance improvement over the initial 2–3 weeks following the cleaning. Currently, the QE of the LCLS photocathode is holding constant at about 1.2×10?4 , with a normalized injector emittance of about 0.3???m for a 150-pC bunch charge. With the proper procedures, the laser-cleaning technique appears to be a viable tool to revive the LCLS photocathode. We present observations and analyses for the QE and emittance evolution in time following the laser-based cleaning of the LCLS photocathode, and comparison to the previous studies, the measured thermal emittance versus the QE and comparison to the theoretical model.

  11. Recirculating accelerator driver for a high-power free-electron laser: A design overview

    SciTech Connect (OSTI)

    Bohn, C.L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    1997-06-01T23:59:59.000Z

    Jefferson Lab is building a free-electron laser (FEL) to produce continuous-wave (cw), kW-level light at 3-6 {mu}m wavelength. A superconducting linac will drive the laser, generating a 5 mA average current, 42 MeV energy electron beam. A transport lattice will recirculate the beam back to the linac for deceleration and conversion of about 75% of its power into rf power. Bunch charge will range up to 135 pC, and bunch lengths will range down to 1 ps in parts of the transport lattice. Accordingly, space charge in the injector and coherent synchrotron radiation in magnetic bends come into play. The machine will thus enable studying these phenomena as a precursor to designing compact accelerators of high-brightness beams. The FEL is scheduled to be installed in its own facility by 1 October 1997. Given the short schedule, the machine design is conservative, based on modifications of the CEBAF cryomodule and MIT-Bates transport lattice. This paper surveys the machine design.

  12. Development of fast heating electron beam annealing setup for ultra high vacuum chamber

    SciTech Connect (OSTI)

    Das, Sadhan Chandra [UGC-DAE Consortium For Scientific Research, University Campus, Khandwa Road, Indore 452 001, MP (India) [UGC-DAE Consortium For Scientific Research, University Campus, Khandwa Road, Indore 452 001, MP (India); School of Electronics, Devi Ahilya University, Indore 452001, MP (India); Institute of Physics, University of Greifswald, Felix Hausdroff Str. 6 (Germany); Majumdar, Abhijit, E-mail: majuabhijit@gmail.com, E-mail: majumdar@uni-greifswald.de; Hippler, R. [Institute of Physics, University of Greifswald, Felix Hausdroff Str. 6 (Germany)] [Institute of Physics, University of Greifswald, Felix Hausdroff Str. 6 (Germany); Katiyal, Sumant [School of Electronics, Devi Ahilya University, Indore 452001, MP (India)] [School of Electronics, Devi Ahilya University, Indore 452001, MP (India); Shripathi, T. [UGC-DAE Consortium For Scientific Research, University Campus, Khandwa Road, Indore 452 001, MP (India)] [UGC-DAE Consortium For Scientific Research, University Campus, Khandwa Road, Indore 452 001, MP (India)

    2014-02-15T23:59:59.000Z

    We report the design and development of a simple, electrically low powered and fast heating versatile electron beam annealing setup (up to 1000?°C) working with ultra high vacuum (UHV) chamber for annealing thin films and multilayer structures. The important features of the system are constant temperature control in UHV conditions for the temperature range from room temperature to 1000?şC with sufficient power of 330 W, at constant vacuum during annealing treatment. It takes approximately 6 min to reach 1000?°C from room temperature (?10{sup ?6} mbar) and 45 min to cool down without any extra cooling. The annealing setup consists of a UHV chamber, sample holder, heating arrangement mounted on suitable UHV electrical feed-through and electronic control and feedback systems to control the temperature within ±1?şC of set value. The outside of the vacuum chamber is cooled by cold air of 20?°C of air conditioning machine used for the laboratory, so that chamber temperature does not go beyond 50?°C when target temperature is maximum. The probability of surface oxidation or surface contamination during annealing is examined by means of x-ray photoelectron spectroscopy of virgin Cu sample annealed at 1000?°C.

  13. 600-T Magnetic Fields due to Cold Electron Flow in a simple Cu-Coil irradiated by High Power Laser pulses

    E-Print Network [OSTI]

    Zhu, Baojun; Yuan, Dawei; Li, Yanfei; Li, Fang; Liao, Guoqian; Zhao, Jiarui; Zhong, Jiayong; Xue, Feibiao; Wei, Huigang; Zhang, Kai; Han, Bo; Pei, Xiaoxing; Liu, Chang; Zhang, Zhe; Wang, Weimin; Zhu, Jianqiang; Zhao, Gang; Zhang, Jie

    2015-01-01T23:59:59.000Z

    A new simple mechanism due to cold electron flow to produce strong magnetic field is proposed. A 600-T strong magnetic field is generated in the free space at the laser intensity of 5.7x10^15 Wcm^-2. Theoretical analysis indicates that the magnetic field strength is proportional to laser intensity. Such a strong magnetic field offers a new experimental test bed to study laser-plasma physics, in particular, fast-ignition laser fusion research and laboratory astrophysics.

  14. PROGRESS WITH FEL-BASED COHERENT ELECTRON COOLING * Vladimir N. Litvinenko#

    E-Print Network [OSTI]

    PROGRESS WITH FEL-BASED COHERENT ELECTRON COOLING * Vladimir N. Litvinenko# , Ilan Ben Zvi, Michael, TJNAF, Newport News, VA, USA Sven Reiche, UCLA, Los Angelis, CA, USA Abstract Cooling intense high, while efficiency of two other cooling methods falls rapidly either at high bunch intensities (i

  15. Toxicity Assessment of Pelvic Intensity-Modulated Radiotherapy With Hypofractionated Simultaneous Integrated Boost to Prostate for Intermediate- and High-Risk Prostate Cancer

    SciTech Connect (OSTI)

    McCammon, Robert; Rusthoven, Kyle E.; Kavanagh, Brian; Newell, Sherri B.S.; Newman, Francis M.S. [Department of Radiation Oncology, University of Colorado Denver, Aurora, CO (United States); Raben, David [Department of Radiation Oncology, University of Colorado Denver, Aurora, CO (United States)], E-mail: david.raben@uchsc.edu

    2009-10-01T23:59:59.000Z

    Purpose: To evaluate the toxicity of pelvic intensity-modulated radiotherapy (IMRT) with hypofractionated simultaneous integrated boost (SIB) to the prostate for patients with intermediate- to high-risk prostate cancer. Methods and Materials: A retrospective toxicity analysis was performed in 30 consecutive patients treated definitively with pelvic SIB-IMRT, all of whom also received androgen suppression. The IMRT plans were designed to deliver 70 Gy in 28 fractions (2.5 Gy/fraction) to the prostate while simultaneously delivering 50.4 Gy in 28 fractions (1.8 Gy/fraction) to the pelvic lymph nodes. The National Cancer Institute Common Terminology Criteria for Adverse Events, version 3.0, was used to score toxicity. Results: The most common acute Grade 2 events were cystitis (36.7%) and urinary frequency/urgency (26.7%). At a median follow-up of 24 months, late toxicity exceeding Grade 2 in severity was uncommon, with two Grade 3 events and one Grade 4 event. Grade 2 or greater acute bowel toxicity was associated with signficantly greater bowel volume receiving {>=}25 Gy (p = .04); Grade 2 or greater late bowel toxicity was associated with a higher bowel maximal dose (p = .04) and volume receiving {>=}50 Gy (p = .02). Acute or late bladder and rectal toxicity did not correlate with any of the dosimetric parameters examined. Conclusion: Pelvic IMRT with SIB to the prostate was well tolerated in this series, with low rates of Grade 3 or greater acute and late toxicity. SIB-IMRT combines pelvic radiotherapy and hypofractionation to the primary site and offers an accelerated approach to treating intermediate- to high-risk disease. Additional follow-up is necessary to fully define the long-term toxicity after hypofractionated, whole pelvic treatment combined with androgen suppression.

  16. Generalized oscillator strengths for inner-shell excitation of SF6 recorded with a high-performance electron energy loss

    E-Print Network [OSTI]

    Hitchcock, Adam P.

    Generalized oscillator strengths for inner-shell excitation of SF6 recorded with a high-performance electron energy loss spectrometer I.G. Eustatiu a , J.T. Francis b , T. Tyliszczak b , C.C. Turci c , A) are reported up to very high momentum transfer. These have been measured with a variable impact energy

  17. RF Power Degradation of GaN High Electron Mobility Transistors Jungwoo Joh and Jess A. del Alamo

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    RF Power Degradation of GaN High Electron Mobility Transistors Jungwoo Joh and Jesús A. del Alamo Transistors. Our technique utilizes RF and DC figures of merit to diagnose the degradation of RF stressed and to introduce new degradation modes. At high power level, RF stress induces a prominent trapping

  18. Abstract--Frequency dispersion of transconductance and output conductance in AlInN/GaN high electron mobility

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    1 Abstract--Frequency dispersion of transconductance and output conductance in AlInN/GaN high is compared to experimental data for several bias conditions and different types of dispersion. Index Terms--AlInN/GaN in recent years on nearly lattice-matched AlInN/GaN high electron mobility transistors (HEMTs

  19. High spatial resolution upgrade of the electron cyclotron emission radiometer for the DIII-D tokamak

    SciTech Connect (OSTI)

    Truong, D. D., E-mail: dtruong@wisc.edu [Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Austin, M. E. [Institute for Fusion Studies, University of Texas, Austin, Texas, 78712 (United States)

    2014-11-15T23:59:59.000Z

    The 40-channel DIII-D electron cyclotron emission (ECE) radiometer provides measurements of T{sub e}(r,t) at the tokamak midplane from optically thick, second harmonic X-mode emission over a frequency range of 83–130 GHz. The frequency spacing of the radiometer's channels results in a spatial resolution of ?1–3 cm, depending on local magnetic field and electron temperature. A new high resolution subsystem has been added to the DIII-D ECE radiometer to make sub-centimeter (0.6–0.8 cm) resolution T{sub e} measurements. The high resolution subsystem branches off from the regular channels’ IF bands and consists of a microwave switch to toggle between IF bands, a switched filter bank for frequency selectivity, an adjustable local oscillator and mixer for further frequency down-conversion, and a set of eight microwave filters in the 2–4 GHz range. Higher spatial resolution is achieved through the use of a narrower (200 MHz) filter bandwidth and closer spacing between the filters’ center frequencies (250 MHz). This configuration allows for full coverage of the 83–130 GHz frequency range in 2 GHz bands. Depending on the local magnetic field, this translates into a “zoomed-in” analysis of a ?2–4 cm radial region. Expected uses of these channels include mapping the spatial dependence of Alfven eigenmodes, geodesic acoustic modes, and externally applied magnetic perturbations. Initial T{sub e} measurements, which demonstrate that the desired resolution is achieved, are presented.

  20. Long-term Survival and Toxicity in Patients Treated With High-Dose Intensity Modulated Radiation Therapy for Localized Prostate Cancer

    SciTech Connect (OSTI)

    Spratt, Daniel E.; Pei, Xin; Yamada, Josh; Kollmeier, Marisa A.; Cox, Brett [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)] [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States); Zelefsky, Michael J., E-mail: zelefskm@mskcc.org [Department of Radiation Oncology, Memorial Sloan-Kettering Cancer Center, New York, New York (United States)

    2013-03-01T23:59:59.000Z

    Purpose: To report long-term survival and toxicity outcomes with the use of high-dose intensity modulated radiation therapy (IMRT) to 86.4 Gy for patients with localized prostate cancer. Methods and Materials: Between August 1997 and December 2008, 1002 patients were treated to a dose of 86.4 Gy using a 5-7 field IMRT technique. Patients were stratified by prognostic risk group based on National Comprehensive Cancer Network risk classification criteria. A total of 587 patients (59%) were treated with neoadjuvant and concurrent androgen deprivation therapy. The median follow-up for the entire cohort was 5.5 years (range, 1-14 years). Results: For low-, intermediate-, and high-risk groups, 7-year biochemical relapse-free survival outcomes were 98.8%, 85.6%, and 67.9%, respectively (P<.001), and distant metastasis-free survival rates were 99.4%, 94.1%, and 82.0% (P<.001), respectively. On multivariate analysis, T stage (P<.001), Gleason score (P<.001), and >50% of initial biopsy positive core (P=.001) were predictive for distant mestastases. No prostate cancer-related deaths were observed in the low-risk group. The 7-year prostate cancer-specific mortality (PCSM) rates, using competing risk analysis for intermediate- and high-risk groups, were 3.3% and 8.1%, respectively (P=.008). On multivariate analysis, Gleason score (P=.004), percentage of biopsy core positivity (P=.003), and T-stage (P=.033) were predictive for PCSM. Actuarial 7-year grade 2 or higher late gastrointestinal and genitourinary toxicities were 4.4% and 21.1%, respectively. Late grade 3 gastrointestinal and genitourinary toxicity was experienced by 7 patients (0.7%) and 22 patients (2.2%), respectively. Of the 427 men with full potency at baseline, 317 men (74%) retained sexual function at time of last follow-up. Conclusions: This study represents the largest cohort of patients treated with high-dose radiation to 86.4 Gy, using IMRT for localized prostate cancer, with the longest follow-up to date. Our findings indicate that this treatment results in excellent clinical outcomes with acceptable toxicity.

  1. Electron-Irradiation Induced Nanocrystallization of Pb(II) in Silica Gels Prepared in High Magnetic Field

    E-Print Network [OSTI]

    Kaito, Takamasa; Kaito, Chihiro

    2015-01-01T23:59:59.000Z

    In a previous study, structure of silica gels prepared in a high magnetic field was investigated. While a direct application of such anisotropic silica gels is for an optical anisotropic medium possessing chemical resistance, we show here their possibility of medium in materials processing. In this direction, for example, silica hydrogels have so far been used as media of crystal growth. In this paper, as opposed to the soft-wet state, dried silica gels have been investigated. We have found that lead (II) nanocrystallites were formed induced by electron irradiation to lead (II)-doped dried silica gels prepared in a high magnetic field such as B = 10 T. Hydrogels made from a sodium metasilicate solution doped with lead (II) acetate were prepared. The dried specimens were irradiated by electrons in a transmission electron microscope environment. Electron diffraction patterns indicated the crystallinity of lead (II) nanocrystallites depending on B. An advantage of this processing technique is that the crystallin...

  2. Recent Progress on Design Studies of High-Luminosity Ring-Ring Electron-Ion Collider at CEBAF

    SciTech Connect (OSTI)

    Zhang, Y; Bruell, A; Chevtsov, P; Derbenev, Y S; Ent, R; Krafft, G A; Li, R; Merminga, L

    2009-05-01T23:59:59.000Z

    The conceptual design of a ring-ring electron-ion collider based on CEBAF has been continuously optimized to cover a wide center-of-mass energy region and to achieve high luminosity and polarization to support next generation nuclear science programs. Here, we summarize the recent design improvements and R&D progress on interaction region optics with chromatic aberration compensation, matching and tracking of electron polarization in the Figure-8 ring, beam-beam simulations and ion beam cooling studies.

  3. Using field emission to control the electron energy distribution in high-pressure microdischarges at microscale dimensions

    SciTech Connect (OSTI)

    Li, Yingjie; Go, David B. [Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)] [Department of Aerospace and Mechanical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)

    2013-12-02T23:59:59.000Z

    Particle simulations of high-pressure microdischarges at gaps below 10 ?m show that the electron energy distribution becomes non-continuous, with discrete peaks corresponding to specific inelastic collisions. The relative magnitude of these peaks and shape of the energy distribution can be directly controlled by the parameter pressure times distance (pd) and the applied potential across the gap. These parameters dictate inelastic collisions experienced by electrons and as both increase the distribution smooths into a Maxwellian-like distribution. By capitalizing on field emission at these dimensions, it is possible to control the energy distribution of free electrons to target specific, energy dependent reactions.

  4. Development of a High-Brightness VHF Electron Source at LBNL

    E-Print Network [OSTI]

    Lidia, Steven M.; Sannibale, Fernando; Staples, John W.; Virostek, Steve P.; Wells, Russell P.

    2008-01-01T23:59:59.000Z

    VHF ELECTRON SOURCE AT LBNL* S. Lidia # , F. Sannibale, J.S. Virostek, R. Wells, LBNL, Berkeley, CA, USA Abstract

  5. All-optical measurement of the hot electron sheath driving laser ion acceleration from thin foils

    E-Print Network [OSTI]

    Jackel, O.

    We present experimental results from an all-optical diagnostic method to directly measure the evolution of the hot-electron distribution driving the acceleration of ions from thin foils using high-intensity lasers. Central ...

  6. Advanced X-Band Test Accelerator for High Brightness Electron and Gamma Ray Beams

    SciTech Connect (OSTI)

    Marsh, Roark; /LLNL, Livermore; Anderson, Scott; /LLNL, Livermore; Barty, Christopher; /LLNL, Livermore; Chu, Tak Sum; /LLNL, Livermore; Ebbers, Chris; /LLNL, Livermore; Gibson, David; /LLNL, Livermore; Hartemann, Fred; /LLNL, Livermore; Adolphsen, Chris; /SLAC; Jongewaard, Erik; /SLAC; Raubenheimer, Tor; /SLAC; Tantawi, Sami; /SLAC; Vlieks, Arnold; /SLAC; Wang, Juwen; /SLAC

    2012-07-03T23:59:59.000Z

    In support of Compton scattering gamma-ray source efforts at LLNL, a multi-bunch test stand is being developed to investigate accelerator optimization for future upgrades. This test stand will enable work to explore the science and technology paths required to boost the current 10 Hz monoenergetic gamma-ray (MEGa-Ray) technology to an effective repetition rate exceeding 1 kHz, potentially increasing the average gamma-ray brightness by two orders of magnitude. Multiple bunches must be of exceedingly high quality to produce narrow-bandwidth gamma-rays. Modeling efforts will be presented, along with plans for a multi-bunch test stand at LLNL. The test stand will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. The photoinjector will be a high gradient standing wave structure, featuring a dual feed racetrack coupler. The accelerator will increase the electron energy so that the emittance can be measured using quadrupole scanning techniques. Multi-bunch diagnostics will be developed so that the beam quality can be measured and compared with theory. Design will be presented with modeling simulations, and layout plans.

  7. ADVANCED X-BAND TEST ACCELERATOR FOR HIGH BRIGHTNESS ELECTRON AND GAMMA RAY BEAMS

    SciTech Connect (OSTI)

    Marsh, R A; Anderson, S G; Barty, C P; Chu, T S; Ebbers, C A; Gibson, D J; Hartemann, F V; Adolphsen, C; Jongewaard, E N; Raubenheimer, T; Tantawi, S G; Vlieks, A E; Wang, J W

    2010-05-12T23:59:59.000Z

    In support of Compton scattering gamma-ray source efforts at LLNL, a multi-bunch test stand is being developed to investigate accelerator optimization for future upgrades. This test stand will enable work to explore the science and technology paths required to boost the current 10 Hz monoenergetic gamma-ray (MEGa-Ray) technology to an effective repetition rate exceeding 1 kHz, potentially increasing the average gamma-ray brightness by two orders of magnitude. Multiple bunches must be of exceedingly high quality to produce narrow-bandwidth gamma-rays. Modeling efforts will be presented, along with plans for a multi-bunch test stand at LLNL. The test stand will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. The photoinjector will be a high gradient standing wave structure, featuring a dual feed racetrack coupler. The accelerator will increase the electron energy so that the emittance can be measured using quadrupole scanning techniques. Multi-bunch diagnostics will be developed so that the beam quality can be measured and compared with theory. Design will be presented with modeling simulations, and layout plans.

  8. A battery-operated, stabilized, high-energy pulsed electron gun for the production of rare gas excimers

    SciTech Connect (OSTI)

    Barcellan, L.; Carugno, G. [INFN Section, Padua (Italy); Berto, E.; Galet, G.; Galeazzi, G. [Department of Physics, University of Padua (Italy); Borghesani, A. F. [INFN Section, Padua (Italy); CNISM Unit, Department of Physics, University of Padua (Italy)

    2011-09-15T23:59:59.000Z

    We report on the design of a new type of hot-filament electron gun delivering fairly high current (a few hundreds of {mu} A) at high voltage (up to 100 kV) in continuous or pulsed mode. Its novel features are that the filament is heated by means of a pack of rechargeable batteries floated atop the high-voltage power supply in order to get rid of bulky isolation transformers, and that the filament current and, hence, the electron gun current, is controlled by a feedback circuit including a superluminescent diode decoupled from the high voltage by means of an optical fiber. This electron gun is intended for general purposes, although we have especially developed it to meet the needs of our experiment on the infrared emission spectroscopy of rare gas excimers. Our experiment requires that the charge injection into the sample is pulsed and constant and stable in time. The new electron gun can deliver several tens of nC per pulse of electrons of energy up to 100 keV into the sample cell. The new design also eliminates ripples in the emission current and ensures up to 12 h of stable performance.

  9. Anomalous Electron Transport Due to Multiple High Frequency Beam Ion Driven Alfven Eigenmode

    SciTech Connect (OSTI)

    N.N. Gorelenkov, D. Stutman, K. Tritz, A. Boozer, L. Delgardo-Aparicio, E. Fredrickson, S. Kaye, and R. White

    2010-07-13T23:59:59.000Z

    We report on the simulations of recently observed correlations of the core electron transport with the sub-thermal ion cyclotron frequency instabilities in low aspect ratio plasmas of the National Spherical Torus Experiment (NSTX). In order to model the electron transport of the guiding center code ORBIT is employed. A spectrum of test functions of multiple core localized Global shear Alfven Eigenmode (GAE) instabilities based on a previously developed theory and experimental observations is used to examine the electron transport properties. The simulations exhibit thermal electron transport induced by electron drift orbit stochasticity in the presence of multiple core localized GAE.

  10. Multiphoton ionization and high-order harmonic generation of He, Ne, and Ar atoms in intense pulsed laser fields: Self-interaction-free time-dependent density-functional theoretical approach

    E-Print Network [OSTI]

    Chu, Shih-I; Tong, Xiao-Min

    2001-06-12T23:59:59.000Z

    We present a detailed study of the multiphoton ionization and high-order harmonic generation (HHG) processes of rare-gas atoms (He, Ne, and Ar) in intense pulsed laser fields by means of a self-interaction-free time-dependent density...

  11. How Electron Spectroscopy with Synchrotron Light Can Help Us Understand High-Tc Superconductivity and Other Complex States of Matter

    SciTech Connect (OSTI)

    Campuzano, Juan Carlos (University of Illinois, Chicago) [University of Illinois, Chicago

    2012-03-07T23:59:59.000Z

    All the physical, chemical, and mechanical properties of materials are controlled by electrons that occupy the highest energy levels in solids, those near the Fermi energy. Many techniques were developed to study those electrons, leading to the great successes of condensed matter physics. Newer and complex materials, such as the high-temperature superconductors, tend to exhibit very large anisotropies in their physical properties, requiring a more detailed knowledge of the behavior of electrons not only as a function of their energy, but also their momentum. Angle-resolved photoemission can contribute to our understanding by providing a great deal of information on many of the momentum-dependent properties of electrons and their interactions. In this talk, I will present a brief overview of how a long-term and focused collaboration between scientists at Argonne and other institutions has contributed to making angle-resolved photoemissions a most useful tool in the study of complex states of matter.

  12. Untangling the contributions of image charge and laser profile for optimal photoemission of high-brightness electron beams

    SciTech Connect (OSTI)

    Portman, J.; Zhang, H.; Makino, K.; Ruan, C. Y.; Berz, M.; Duxbury, P. M. [Physics and Astronomy Department, Michigan State University, East Lansing, Michigan 48824 (United States)

    2014-11-07T23:59:59.000Z

    Using our model for the simulation of photoemission of high brightness electron beams, we investigate the virtual cathode physics and the limits to spatio-temporal and spectroscopic resolution originating from the image charge on the surface and from the profile of the exciting laser pulse. By contrasting the effect of varying surface properties (leading to expanding or pinned image charge), laser profiles (Gaussian, uniform, and elliptical), and aspect ratios (pancake- and cigar-like) under different extraction field strengths and numbers of generated electrons, we quantify the effect of these experimental parameters on macroscopic pulse properties such as emittance, brightness (4D and 6D), coherence length, and energy spread. Based on our results, we outline optimal conditions of pulse generation for ultrafast electron microscope systems that take into account constraints on the number of generated electrons and on the required time resolution.

  13. High power microwave generator

    DOE Patents [OSTI]

    Ekdahl, C.A.

    1983-12-29T23:59:59.000Z

    A microwave generator efficiently converts the energy of an intense relativistic electron beam (REB) into a high-power microwave emission using the Smith-Purcell effect which is related to Cerenkov radiation. Feedback for efficient beam bunching and high gain is obtained by placing a cylindrical Smith-Purcell transmission grating on the axis of a toroidal resonator. High efficiency results from the use of a thin cold annular highly-magnetized REB that is closely coupled to the resonant structure.

  14. Method and apparatus for a high-resolution three dimensional confocal scanning transmission electron microscope

    DOE Patents [OSTI]

    de Jonge, Niels (Oak Ridge, TN) [Oak Ridge, TN

    2010-08-17T23:59:59.000Z

    A confocal scanning transmission electron microscope which includes an electron illumination device providing an incident electron beam propagating in a direction defining a propagation axis, and a precision specimen scanning stage positioned along the propagation axis and movable in at least one direction transverse to the propagation axis. The precision specimen scanning stage is configured for positioning a specimen relative to the incident electron beam. A projector lens receives a transmitted electron beam transmitted through at least part of the specimen and focuses this transmitted beam onto an image plane, where the transmitted beam results from the specimen being illuminated by the incident electron beam. A detection system is placed approximately in the image plane.

  15. High resolution transmission electron microscopy of melamine-formaldehyde aerogels and silica aerogels

    SciTech Connect (OSTI)

    Ruben, G.C. (Dartmouth Coll., Hanover, NH (United States). Dept. of Biological Sciences)

    1991-09-01T23:59:59.000Z

    The goal of the high resolution transmission electron microscopy (HRTEM) was to image the structure of two tetramethyl orthosilicate (TMOS) and two melamine-formaldehyde (MF) aerogels at the single polymer chain level{sup 1,2}. With this level of structural resolution we hoped to interrelate each aerogel's structure with its physical properties and its method of synthesis. Conventional single-step base catalysed TMOS aerogels show strings of spheroidal particles linked together with minimal necking. The spheroidal particles range from 86--132 {Angstrom} and average 113{plus minus}10 {Angstrom} in diameter{sup 2}. In contrast the TMOS aerogels reported on here were made by a two step method. After extended silica chains are grown in solution under acidic conditions with a substoichiometric amount of water, the reaction is stopped and the methanol hydrolysed from TMOS is removed. Then base catalysis and additional water are added to cause gel formation is a nonalcoholic solvent. The MF aerogels were prepared for HRTEM by fracturing them on a stereo microscope stage with razor knife so that fractured pieces with smooth flat surfaces could be selected for platinum-carbon replication. The two silica (TMOS) aerogels were both transparent and difficult to see. These aerogels were fractured on a stereo microscope stage with tweezers. 6 refs., 4 figs.

  16. The development of high-performance alkali-hybrid polarized He3 targets for electron scattering

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

    Singh, Jaideep T. [University of Virginia, Charlottesville, VA (United States); Argonne National Lab., Argonne, IL (United States); Technische Universitat Munchen, Exzellenzcluster Universe, Garching, Germany (Europe); Dolph, Peter A.M. [University of Virginia, Charlottesville, VA (United States); Tobias, William Al [University of Virginia, Charlottesville, VA (United States); Averett, Todd D. [College of William and Mary, Williamsburg, VA (United States); Kelleher, Aiden [College of William and Mary, Williamsburg, VA (United States); Mooney, K. E. [University of Virginia, Charlottesville, VA (United States); Nelyubin, Vladimir V. [University of Virginia, Charlottesville, VA (United States); Wang, Yunxiao [University of Virginia, Charlottesville, VA (United States); Zheng, Yuan [University of Virginia, Charlottesville, VA (United States); Cates, Gordon D. [University of Virginia, Charlottesville, VA (United States)

    2015-05-01T23:59:59.000Z

    We present the development of high-performance polarized łHe targets for use in electron scattering experiments that utilize the technique of alkali-hybrid spin-exchange optical pumping. We include data obtained during the characterization of 24 separate target cells, each of which was constructed while preparing for one of four experiments at Jefferson Laboratory in Newport News, Virginia. The results presented here document dramatic improvement in the performance of polarized łHe targets, as well as the target properties and operating parameters that made those improvements possible. Included in our measurements were determinations of the so-called X-factors that quantify a temperature-dependent and as-yet poorly understood spin-relaxation mechanism that limits the maximum achievable łHe polarization to well under 100%. The presence of this spin-relaxation mechanism was clearly evident in our data. We also present results from a simulation of the alkali-hydrid spin-exchange optical pumping process that was developed to provide guidance in the design of these targets. Good agreement with actual performance was obtained by including details such as off-resonant optical pumping. Now benchmarked against experimental data, the simulation is useful for the design of future targets. Included in our results is a measurement of the K- łHe spin-exchange rate coefficient $k^\\mathrm{K}_\\mathrm{se} = \\left ( 7.46 \\pm 0.62 \\right )\\!\\times\\!10^{-20}\\ \\mathrm{cm^3/s}$ over the temperature range 503 K to 563 K.

  17. An improved measurement of electron-ion recombination in high-pressure xenon gas

    E-Print Network [OSTI]

    NEXT Collaboration; L. Serra; M. Sorel; V. Álvarez; F. I. G. Borges; M. Camargo; S. Cárcel; S. Cebrián; A. Cervera; C. A. N. Conde; T. Dafni; J. Díaz; R. Esteve; L. M. P. Fernandes; P. Ferrario; A. L. Ferreira; E. D. C. Freitas; V. M. Gehman; A. Goldschmidt; J. J. Gómez-Cadenas; D. González-Díaz; R. M. Gutiérrez; J. Hauptman; J. A. Hernando Morata; D. C. Herrera; I. G. Irastorza; L. Labarga; A. Laing; I. Liubarsky; N. Lopez-March; D. Lorca; M. Losada; G. Luzón; A. Marí; J. Martín-Albo; G. Martínez-Lema; A. Martínez; T. Miller; F. Monrabal; M. Monserrate; C. M. B. Monteiro; F. J. Mora; L. M. Moutinho; J. Muńoz Vidal; M. Nebot-Guinot; D. Nygren; C. A. B. Oliveira; J. Pérez; J. L. Pérez Aparicio; M. Querol; J. Renner; L. Ripoll; A. Rodríguez; J. Rodríguez; F. P. Santos; J. M. F. dos Santos; D. Shuman; A. Simón; C. Sofka; J. F. Toledo; J. Torrent; Z. Tsamalaidze; J. F. C. A. Veloso; J. A. Villar; R. Webb; J. T. White; N. Yahlali

    2015-02-03T23:59:59.000Z

    We report on results obtained with the NEXT-DEMO prototype of the NEXT-100 high-pressure xenon gas time projection chamber (TPC), exposed to an alpha decay calibration source. Compared to our previous measurements with alpha particles, an upgraded detector and improved analysis techniques have been used. We measure event-by-event correlated fluctuations between ionization and scintillation due to electron-ion recombination in the gas, with correlation coeffcients between -0.80 and -0.56 depending on the drift field conditions. By combining the two signals, we obtain a 2.8 % FWHM energy resolution for 5.49 MeV alpha particles and a measurement of the optical gain of the electroluminescent TPC. The improved energy resolution also allows us to measure the specific activity of the radon in the gas due to natural impurities. Finally, we measure the average ratio of excited to ionized atoms produced in the xenon gas by alpha particles to be $0.561\\pm 0.045$, translating into an average energy to produce a primary scintillation photon of $W_{\\rm ex}=(39.2\\pm 3.2)$ eV.

  18. Effect of buffer structures on AlGaN/GaN high electron mobility transistor reliability

    SciTech Connect (OSTI)

    Liu, L. [University of Florida, Gainesville; Xi, Y. Y. [University of Florida, Gainesville; Ren, F. [University of Florida; Pearton, S. J. [University of Florida; Laboutin, O. [Kopin Corporation, Taunton, MA; Cao, Yu [Kopin Corporation, Taunton, MA; Johnson, Wayne J. [Kopin Corporation, Taunton, MA; Kravchenko, Ivan I [ORNL

    2012-01-01T23:59:59.000Z

    AlGaN/GaN high electron mobility transistors (HEMTs) with three different types of buffer layers, including a GaN/AlGaN composite layer, or 1 or 2 lm GaN thick layers, were fabricated and their reliability compared. The HEMTs with the thick GaN buffer layer showed the lowest critical voltage (Vcri) during off-state drain step-stress, but this was increased by around 50% and 100% for devices with the composite AlGaN/GaN buffer layers or thinner GaN buffers, respectively. The Voff - state for HEMTs with thin GaN and composite buffers were 100 V, however, this degraded to 50 60V for devices with thick GaN buffers due to the difference in peak electric field near the gate edge. A similar trend was observed in the isolation breakdown voltage measurements, with the highest Viso achieved based on thin GaN or composite buffer designs (600 700 V), while a much smaller Viso of 200V was measured on HEMTs with the thick GaN buffer layers. These results demonstrate the strong influence of buffer structure and defect density on AlGaN/GaN HEMT performance and reliability.

  19. Group-III nitride based high electron mobility transistor (HEMT) with barrier/spacer layer

    DOE Patents [OSTI]

    Chavarkar, Prashant; Smorchkova, Ioulia P.; Keller, Stacia; Mishra, Umesh; Walukiewicz, Wladyslaw; Wu, Yifeng

    2005-02-01T23:59:59.000Z

    A Group III nitride based high electron mobility transistors (HEMT) is disclosed that provides improved high frequency performance. One embodiment of the HEMT comprises a GaN buffer layer, with an Al.sub.y Ga.sub.1-y N (y=1 or y 1) layer on the GaN buffer layer. An Al.sub.x Ga.sub.1-x N (0.ltoreq.x.ltoreq.0.5) barrier layer on to the Al.sub.y Ga.sub.1-y N layer, opposite the GaN buffer layer, Al.sub.y Ga.sub.1-y N layer having a higher Al concentration than that of the Al.sub.x Ga.sub.1-x N barrier layer. A preferred Al.sub.y Ga.sub.1-y N layer has y=1 or y.about.1 and a preferred Al.sub.x Ga.sub.1-x N barrier layer has 0.ltoreq.x.ltoreq.0.5. A 2DEG forms at the interface between the GaN buffer layer and the Al.sub.y Ga.sub.1-y N layer. Respective source, drain and gate contacts are formed on the Al.sub.x Ga.sub.1-x N barrier layer. The HEMT can also comprising a substrate adjacent to the buffer layer, opposite the Al.sub.y Ga.sub.1-y N layer and a nucleation layer between the Al.sub.x Ga.sub.1-x N buffer layer and the substrate.

  20. Noninvasive measurement of micron electron beam size of high energy using diffraction radiation

    E-Print Network [OSTI]

    G. Naumenko

    2004-05-31T23:59:59.000Z

    Treatments of the usage of optical diffraction radiation from the relativistic electrons moving though a conductive slit for the noninvasive transverse beam size measurement encounter hard limitation of the method sensitivity for the electron energy larger than 1 GeV. We consider in this article a possibility of application in a diffraction radiation technique the artificial phase shift, which can take place when transverse electron position varies. This allows us to realize the nonivasive measurements of transverse size of supper-relativistic electron beams with the small emittance.

  1. High-Affinity Binding and Direct Electron Transfer to Solid Metals...

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

    been suggested to function in concert with other membrane proteins as one of the terminal electron donors in the metal reductase protein complex of Shewanella oneidensis...

  2. Photo-stimulated low electron temperature high current diamond film field emission cathode

    DOE Patents [OSTI]

    Shurter; Roger Philips (Los Alamos, NM), Devlin; David James (Santa Fe, NM), Moody; Nathan Andrew (Los Alamos, NM), Taccetti; Jose Martin (Santa Fe, NM), Russell; Steven John (Los Alamos, NM)

    2012-07-24T23:59:59.000Z

    An electron source includes a back contact surface having a means for attaching a power source to the back contact surface. The electron source also includes a layer comprising platinum in direct contact with the back contact surface, a composite layer of single-walled carbon nanotubes embedded in platinum in direct contact with the layer comprising platinum. The electron source also includes a nanocrystalline diamond layer in direct contact with the composite layer. The nanocrystalline diamond layer is doped with boron. A portion of the back contact surface is removed to reveal the underlying platinum. The electron source is contained in an evacuable container.

  3. Stretchable form of single crystal silicon for high performance electronics on rubber substrates

    DOE Patents [OSTI]

    Rogers, John A. (Champaign, IL); Khang, Dahl-Young (Seoul, KR); Sun, Yugang (Naperville, IL); Menard, Etienne (Durham, NC)

    2012-06-12T23:59:59.000Z

    The present invention provides stretchable, and optionally printable, semiconductors and electronic circuits capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Stretchable semiconductors and electronic circuits of the present invention preferred for some applications are flexible, in addition to being stretchable, and thus are capable of significant elongation, flexing, bending or other deformation along one or more axes. Further, stretchable semiconductors and electronic circuits of the present invention may be adapted to a wide range of device configurations to provide fully flexible electronic and optoelectronic devices.

  4. Stretchable form of single crystal silicon for high performance electronics on rubber substrates

    DOE Patents [OSTI]

    University of Illinois (Urbana, IL)

    2009-04-21T23:59:59.000Z

    The present invention provides stretchable, and optionally printable, semiconductors and electronic circuits capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Stretchable semiconductors and electronic circuits of the present invention preferred for some applications are flexible, in addition to being stretchable, and thus are capable of significant elongation, flexing, bending or other deformation along one or more axes. Further, stretchable semiconductors and electronic circuits of the present invention may be adapted to a wide range of device configurations to provide fully flexible electronic and optoelectronic devices.

  5. Stretchable form of single crystal silicon for high performance electronics on rubber substrates

    SciTech Connect (OSTI)

    Rogers, John A.; Khang, Dahl-Young; Sun, Yugang; Menard, Etienne

    2014-06-17T23:59:59.000Z

    The present invention provides stretchable, and optionally printable, semiconductors and electronic circuits capable of providing good performance when stretched, compressed, flexed or otherwise deformed. Stretchable semiconductors and electronic circuits of the present invention preferred for some applications are flexible, in addition to being stretchable, and thus are capable of significant elongation, flexing, bending or other deformation along one or more axes. Further, stretchable semiconductors and electronic circuits of the present invention may be adapted to a wide range of device configurations to provide fully flexible electronic and optoelectronic devices.

  6. Coherent control and giant enhancement of multiphoton ionization and high-order-harmonic generation driven by intense frequency-comb laser fields: An ab initio theoretical investigation

    E-Print Network [OSTI]

    Chu, Shih-I; Zhao, Di; Li, Fu-li

    2013-04-11T23:59:59.000Z

    the intensity of the driving frequency-comb laser fields. However, the two-level model does not take into account the effects of multilevel structure and ionization, which are inherent in real atomic and/or molecular systems driven by intense laser fields... function. In general, the carrier frequency ?c is not necessarily one of the comb frequencies nor does it equal ?0. Due to the incommensuration between the time period (=2?/?c) of the carrier wave and the time interval ? of the pulse envelope, there is a...

  7. Extreme-ultraviolet spectra of highly charged Pt ions with several valence-shell electrons: Observation and accurate calculations

    SciTech Connect (OSTI)

    Traebert, Elmar [Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94550-9234 (United States); Astronomisches Institut, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Clementson, Joel; Beiersdorfer, Peter [Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94550-9234 (United States); Santana, Juan A.; Ishikawa, Yasuyuki [Department of Chemistry and Chemical Physics Program, University of Puerto Rico, P.O. Box 23346, San Juan, Puerto Rico 00931-3346 (Puerto Rico)

    2010-12-15T23:59:59.000Z

    Previous observations of Cu- through Ge-like high-Z ions have demonstrated that accurate measurements and theory agree well for ions with a single valence electron but that additional electrons in the valence shell cause progressively worsening computational problems. We have obtained highly resolved euv spectra of Pt (Z=78) ions in an electron-beam ion trap. The measured wavelengths are compared to the results of a number of recent large-scale calculations, including our own multireference Moeller-Plesset computations. The latter calculations match the best for Cu- and Zn-like ions and represent an order-of-magnitude improvement in predictive accuracy for Ga- and Ge-like ions.

  8. Ab initio study of the orientation effects in multiphoton ionization and high-order harmonic generation from the ground and excited electronic states of H2+

    E-Print Network [OSTI]

    Chu, Shih-I; Telnov, Dmitry A.

    2007-10-11T23:59:59.000Z

    We present an ab initio three-dimensional (3D) calculation of multiphoton ionization (MPI) and high-order harmonic generation (HHG) of the hydrogen molecular ions subject to intense linearly polarized laser pulses. The orientation of the molecular...

  9. High-Energy-Resolution Inelastic Electron and Proton Scattering and the Multiphonon Nature of Mixed-Symmetry 2

    E-Print Network [OSTI]

    Ponomarev, Vladimir

    , University of Cape Town, Rondebosch 7700, South Africa 3 School of Physics, University of the Witwatersrand, Johannesburg 2050, South Africa 4 iThemba LABS, PO Box 722, Somerset West 7129, South Africa 5 Institut fuHigh-Energy-Resolution Inelastic Electron and Proton Scattering and the Multiphonon Nature of Mixed

  10. In this paper, an AlGaN/GaN high electron mobility transistor (HEMT) device based on a

    E-Print Network [OSTI]

    Yang, Kyounghoon

    205 Abstract In this paper, an AlGaN/GaN high electron mobility transistor (HEMT) device basedBm at 2 GHz have been demonstrated from the fabricated device. 1. Introduction In recent years, AlGaN/GaN noise amplifier and switch. Superior results have been reported in microwave power performance of AlGaN/GaN

  11. Self-focusing, channel formation, and high-energy ion generation in interaction of an intense short laser pulse with a He jet

    E-Print Network [OSTI]

    Umstadter, Donald

    A number of proposed applications of ultrahigh intensity short laser pulses require laser guiding-focusing related to plasma motion during the laser pulse. Although the self-focusing of a short laser pulse motion induced by a short relativistic laser pulse was studied in hydrodynamic simula

  12. Structural forms of single crystal semiconductor nanoribbons for high-performance stretchable electronics

    E-Print Network [OSTI]

    Rogers, John A.

    and other devices that involve relatively low coverage of active electronics.27,28 This feature article electronics Yugang Sun*a and John A. Rogers*b Received 11th October 2006, Accepted 11th January 2007 First. These results, in combination with active functional device elements that can be formed on the surfaces

  13. Thermally Activated, Inverted Interfacial Electron Transfer Kinetics: High Driving Force Reactions between Tin Oxide Nanoparticles and

    E-Print Network [OSTI]

    between Tin Oxide Nanoparticles and Electrostatically-Bound Molecular Reactants Dennis A. Gaal and Joseph: The kinetics and mechanism of fast electron transfer (ET) between tin oxide nanoparticles and electrostatically-order studies establish that, at least in the short time regime, electrons are transferred directly from the tin

  14. Performance Characteristics Of An Intensity Modulated Advanced X-Ray Source (IMAXS) For Homeland Security Applications

    SciTech Connect (OSTI)

    Langeveld, Willem G. J.; Brown, Craig; Condron, Cathie; Ingle, Mike [Rapiscan Laboratories, Inc., 520 Almanor Ave., Sunnyvale, CA 94085 (United States); Christensen, Phil A.; Johnson, William A.; Owen, Roger D. [HESCO/PTSE Inc., 2501 Monarch St., Alameda, CA 94501 (United States); Hernandez, Michael; Schonberg, Russell G. [XScell Corp., 2134 Old Middlefield Way, Mountain View, CA 94043 (United States); Ross, Randy [Stangenes Industries, Inc., 1052 East Meadow Circle, Palo Alto, CA 94303 (United States)

    2011-06-01T23:59:59.000Z

    X-ray cargo inspection systems for the detection and verification of threats and contraband must address stringent, competitive performance requirements. High x-ray intensity is needed to penetrate dense cargo, while low intensity is desirable to minimize the radiation footprint, i.e. the size of the controlled area, required shielding and the dose to personnel. In a collaborative effort between HESCO/PTSE Inc., XScell Corp., Stangenes Industries, Inc. and Rapiscan Laboratories, Inc., an Intensity Modulated Advanced X-ray Source (IMAXS) was designed and produced. Cargo inspection systems utilizing such a source have been projected to achieve up to 2 inches steel-equivalent greater penetration capability, while on average producing the same or smaller radiation footprint as present fixed-intensity sources. Alternatively, the design can be used to obtain the same penetration capability as with conventional sources, but reducing the radiation footprint by about a factor of three. The key idea is to anticipate the needed intensity for each x-ray pulse by evaluating signal strength in the cargo inspection system detector array for the previous pulse. The IMAXS is therefore capable of changing intensity from one pulse to the next by an electronic signal provided by electronics inside the cargo inspection system detector array, which determine the required source intensity for the next pulse. We report on the completion of a 9 MV S-band (2998 MHz) IMAXS source and comment on its performance.

  15. Scattering due to Schottky barrier height spatial fluctuation on two dimensional electron gas in AlGaN/GaN high electron mobility transistors

    SciTech Connect (OSTI)

    Li, Huijie; Liu, Guipeng, E-mail: liugp@semi.ac.cn; Wei, Hongyuan; Jiao, Chunmei; Wang, Jianxia; Zhang, Heng; Dong Jin, Dong; Feng, Yuxia; Yang, Shaoyan, E-mail: sh-yyang@semi.ac.cn; Wang, Lianshan; Zhu, Qinsheng; Wang, Zhan-Guo [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, People's Republic of China and Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)] [Key Laboratory of Semiconductor Materials Science, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083, People's Republic of China and Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, P.O. Box 912, Beijing 100083 (China)

    2013-12-02T23:59:59.000Z

    A scattering mechanism related to the Schottky barrier height (SBH) spatial fluctuation of the two dimensional electron gas (2DEG) in AlGaN/GaN heterostructures is presented. We find that the low field mobility is on the order of 10{sup 4}–10{sup 6} cm{sup 2}/Vs. The 2DEG transport properties are found to be influenced by both the mobility and 2DEG density variations caused by the SBH fluctuation. Our results indicate that a uniform Schottky contact is highly desired to minimize the influence of SBH inhomogeneity on the device performance.

  16. Nuclear Instruments and Methods in Physics Research A 528 (2004) 1518 First lasing at the high-power free electron laser at Siberian

    E-Print Network [OSTI]

    Kozak, Victor R.

    2004-01-01T23:59:59.000Z

    -power free electron laser at Siberian center for photochemistry research E.A. Antokhin, R.R. Akberdin, V in April 2003 on a high-power free electron laser (FEL) constructed at the Siberian Center. 2. Accelerator­recuperator Full-scale Novosibirsk free electron laser is to be based on multi

  17. High and low frequency instabilities driven by counter-streaming electron beams in space plasmas

    SciTech Connect (OSTI)

    Mbuli, L. N. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200, Republic of South Africa (South Africa); University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa); Maharaj, S. K. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200, Republic of South Africa (South Africa); Bharuthram, R. [University of the Western Cape, Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa)

    2014-05-15T23:59:59.000Z

    A four-component plasma composed of a drifting (parallel to ambient magnetic field) population of warm electrons, drifting (anti-parallel to ambient magnetic field) cool electrons, stationary hot electrons, and thermal ions is studied in an attempt to further our understanding of the excitation mechanisms of broadband electrostatic noise (BEN) in the Earth's magnetospheric regions such as the magnetosheath, plasmasphere, and plasma sheet boundary layer (PSBL). Using kinetic theory, beam-driven electrostatic instabilities such as the ion-acoustic, electron-acoustic instabilities are found to be supported in our multi-component model. The dependence of the instability growth rates and real frequencies on various plasma parameters such as beam speed, number density, temperature, and temperature anisotropy of the counter-streaming (relative to ambient magnetic field) cool electron beam are investigated. It is found that the number density of the anti-field aligned cool electron beam and drift speed play a central role in determining which instability is excited. Using plasma parameters which are closely correlated with the measurements made by the Cluster satellites in the PSBL region, we find that the electron-acoustic and ion-acoustic instabilities could account for the generation of BEN in this region.

  18. The development of high-performance alkali-hybrid polarized He3 targets for electron scattering

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

    Singh, Jaideep T.; Dolph, Peter A.M.; Tobias, William Al; Averett, Todd D.; Kelleher, Aiden; Mooney, K. E.; Nelyubin, Vladimir V.; Wang, Yunxiao; Zheng, Yuan; Cates, Gordon D.

    2015-05-01T23:59:59.000Z

    We present the development of high-performance polarized łHe targets for use in electron scattering experiments that utilize the technique of alkali-hybrid spin-exchange optical pumping. We include data obtained during the characterization of 24 separate target cells, each of which was constructed while preparing for one of four experiments at Jefferson Laboratory in Newport News, Virginia. The results presented here document dramatic improvement in the performance of polarized łHe targets, as well as the target properties and operating parameters that made those improvements possible. Included in our measurements were determinations of the so-called X-factors that quantify a temperature-dependent and as-yet poorlymore »understood spin-relaxation mechanism that limits the maximum achievable łHe polarization to well under 100%. The presence of this spin-relaxation mechanism was clearly evident in our data. We also present results from a simulation of the alkali-hydrid spin-exchange optical pumping process that was developed to provide guidance in the design of these targets. Good agreement with actual performance was obtained by including details such as off-resonant optical pumping. Now benchmarked against experimental data, the simulation is useful for the design of future targets. Included in our results is a measurement of the K- łHe spin-exchange rate coefficient $k^\\mathrm{K}_\\mathrm{se} = \\left ( 7.46 \\pm 0.62 \\right )\\!\\times\\!10^{-20}\\ \\mathrm{cm^3/s}$ over the temperature range 503 K to 563 K.« less

  19. Extended-range grazing-incidence spectrometer for high-resolution extreme ultraviolet measurements on an electron beam ion trap

    SciTech Connect (OSTI)

    Beiersdorfer, P.; Magee, E. W.; Brown, G. V.; Träbert, E.; Widmann, K. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Hell, N. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Dr. Remeis-Sternwarte and ECAP, Universität Erlangen-Nürnberg, 96049 Bamberg (Germany)

    2014-11-15T23:59:59.000Z

    A high-resolution grazing-incidence grating spectrometer has been implemented on the Livermore electron beam ion traps for performing very high-resolution measurements in the soft x-ray and extreme ultraviolet region spanning from below 10 Ĺ to above 300 Ĺ. The instrument operates without an entrance slit and focuses the light emitted by highly charged ions located in the roughly 50 ?m wide electron beam onto a cryogenically cooled back-illuminated charge-coupled device detector. The measured line widths are below 0.025 Ĺ above 100 Ĺ, and the resolving power appears to be limited by the source size and Doppler broadening of the trapped ions. Comparisons with spectra obtained with existing grating spectrometers show an order of magnitude improvement in spectral resolution.

  20. Effect of electron density profile on power absorption of high frequency electromagnetic waves in plasma

    SciTech Connect (OSTI)

    Xi Yanbin; Liu Yue [MOE Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2012-07-15T23:59:59.000Z

    Considering different typical electron density profiles, a multi slab approximation model is built up to study the power absorption of broadband (0.75-30 GHz) electromagnetic waves in a partially ionized nonuniform magnetized plasma layer. Based on the model, the power absorption spectra for six cases are numerically calculated and analyzed. It is shown that the absorption strongly depends on the electron density fluctuant profile, the background electron number density, and the collision frequency. A potential optimum profile is also analyzed and studied with some particular parameters.

  1. Transport of elliptic intense charged -particle beams

    E-Print Network [OSTI]

    Zhou, J. (Jing), 1978-

    2006-01-01T23:59:59.000Z

    The transport theory of high-intensity elliptic charged-particle beams is presented. In particular, the halo formation and beam loss problem associated with the high space charge and small-aperture structure is addressed, ...

  2. High-Gain Harmonic Generation Free-Electron Laser at Saturation

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

    Gain Harmonic Generation Free-Electron Laser at Saturation T. Shaftan 1 , M. Babzien 1 , I. Ben-Zvi 1 , S. G. Biedron 2 , L. F. DiMauro 1 , A. Doyuran 1 , J.N. Galayda 2 , E....

  3. A highly miniaturized electron and ion energy spectrometer prototype for the rapid analysis of space plasmas

    SciTech Connect (OSTI)

    Bedington, R., E-mail: r.bedington@stp.isas.jaxa.jp [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara 252-5210 (Japan); Kataria, D. O.; Smith, A. [Mullard Space Science Laboratory, University College London, Holmbury St. Mary RH5 6NT (United Kingdom)] [Mullard Space Science Laboratory, University College London, Holmbury St. Mary RH5 6NT (United Kingdom)

    2014-02-15T23:59:59.000Z

    MEMS (Micro Electro-Mechanical Systems) plasma analyzers are a promising possibility for future space missions but conventional instrument designs are not necessarily well suited to micro-fabrication. Here, a candidate design for a MEMS-based instrument has been prototyped using electron-discharge machining. The device features 10 electrostatic analyzers that, with a single voltage applied to it, allow five different energies of electron and five different energies of positive ion to be simultaneously sampled. It has been simulated using SIMION and the electron response characteristics tested in an instrument calibration chamber. Small deviations found in the electrode spacing of the as-built prototype were found to have some effect on the electron response characteristics but do not significantly impede its performance.

  4. Intrinsic Electronic Transport Properties of High-Quality Monolayer and Bilayer MoS[subscript 2

    E-Print Network [OSTI]

    Baugher, Britton W. H.

    We report electronic transport measurements of devices based on monolayers and bilayers of the transition-metal dichalcogenide MoS[subscript 2]. Through a combination of in situ vacuum annealing and electrostatic gating ...

  5. Electron beam melting at high pressures with a vacuum separator/plasma lens

    SciTech Connect (OSTI)

    Hershcovitch, A.

    1995-12-31T23:59:59.000Z

    Plasmas can be used to provide a vacuum-atmosphere interface or separation between vacua regions as an alternative to differential pumping. Vacuum-atmosphere interface utilizing a cascade arc discharge was successfully demonstrated and a 175 keV electron beam was successfully propagated from vacuum through such a plasma interface and out into atmospheric pressure. This plasma device also functions as an effective plasma tens. Such a device can be adopted for use in electron beam melting.

  6. Highly coherent electron beam from a laser-triggered tungsten needle tip

    E-Print Network [OSTI]

    Ehberger, Dominik; Eisele, Max; Krüger, Michael; Noe, Jonathan; Högele, Alexander; Hommelhoff, Peter

    2014-01-01T23:59:59.000Z

    We report on a quantitative measurement of the spatial coherence of electrons emitted from a sharp metal needle tip. We investigate the coherence in photoemission using near-ultraviolet laser triggering with a photon energy of 3.1 eV and compare it to DC-field emission. A carbon-nanotube is brought in close proximity to the emitter tip to act as an electrostatic biprism. From the resulting electron matter wave interference fringes we deduce an upper limit of the effective source radius both in laser-triggered and DC-field emission mode, which quantifies the spatial coherence of the emitted electron beam. We obtain $(0.80\\pm 0.05)\\,$nm in laser-triggered and $(0.55\\pm 0.02)\\,$nm in DC-field emission mode, revealing that the outstanding coherence properties of electron beams from needle tip field emitters are largely maintained in laser-induced emission. In addition, the relative coherence width of 0.36 of the photoemitted electron beam is the largest observed so far. The preservation of electronic coherence du...

  7. An accurate online calibration system based on combined clamp-shape coil for high voltage electronic current transformers

    SciTech Connect (OSTI)

    Li, Zhen-hua; Li, Hong-bin; Zhang, Zhi [CEEE of Huazhong University of Science and Technology, Wuhan 430074 (China) [CEEE of Huazhong University of Science and Technology, Wuhan 430074 (China); State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Wuhan 430074 (China)

    2013-07-15T23:59:59.000Z

    Electronic transformers are widely used in power systems because of their wide bandwidth and good transient performance. However, as an emerging technology, the failure rate of electronic transformers is higher than that of traditional transformers. As a result, the calibration period needs to be shortened. Traditional calibration methods require the power of transmission line be cut off, which results in complicated operation and power off loss. This paper proposes an online calibration system which can calibrate electronic current transformers without power off. In this work, the high accuracy standard current transformer and online operation method are the key techniques. Based on the clamp-shape iron-core coil and clamp-shape air-core coil, a combined clamp-shape coil is designed as the standard current transformer. By analyzing the output characteristics of the two coils, the combined clamp-shape coil can achieve verification of the accuracy. So the accuracy of the online calibration system can be guaranteed. Moreover, by employing the earth potential working method and using two insulating rods to connect the combined clamp-shape coil to the high voltage bus, the operation becomes simple and safe. Tests in China National Center for High Voltage Measurement and field experiments show that the proposed system has a high accuracy of up to 0.05 class.

  8. Plasmonic terahertz detectors based on a high-electron mobility GaAs/AlGaAs heterostructure

    SciTech Connect (OSTI)

    Bia?ek, M., E-mail: marcin.bialek@fuw.edu.pl; Witowski, A. M.; Grynberg, M.; ?usakowski, J. [Faculty of Physics, University of Warsaw, ul. Ho?a 69, 00-681 Warsaw (Poland); Orlita, M.; Potemski, M. [Laboratoire National des Champs Magnetiques Intenses, CNRS-UJF-UPS-INSA, 25, avenue des Martyrs, 38042 Grenoble (France); Czapkiewicz, M. [Institute of Physics, PAS, al. Lotników 32/46, 02-668 Warsaw (Poland); Wróbel, J. [Institute of Physics, PAS, al. Lotników 32/46, 02-668 Warsaw (Poland); Faculty of Mathematics and Natural Sciences, Rzeszów University, al. Rejtana 16A, 35-959 Rzeszów (Poland); Umansky, V. [Weizmann Institute of Science, Rehevot 76100 (Israel)

    2014-06-07T23:59:59.000Z

    In order to characterize magnetic field (B) tunable THz plasmonic detectors, spectroscopy experiments were carried out at liquid helium temperatures and high magnetic fields on devices fabricated on a high electron mobility GaAs/AlGaAs heterostructure. The samples were either gated (the gate of a meander shape) or ungated. Spectra of a photovoltage generated by THz radiation were obtained as a function of B at a fixed THz excitation from a THz laser or as a function of THz photon frequency at a fixed B with a Fourier spectrometer. In the first type of measurements, the wave vector of magnetoplasmons excited was defined by geometrical features of samples. It was also found that the magnetoplasmon spectrum depended on the gate geometry which gives an additional parameter to control plasma excitations in THz detectors. Fourier spectra showed a strong dependence of the magnetoplasmon resonance amplitude on the conduction-band electron filling factor which was explained within a model of the electron gas heating with THz radiation. The study allows to define both the advantages and limitations of plasmonic devices based on high-mobility GaAs/AlGaAs heterostructures for THz detection at low temperatures and high magnetic fields.

  9. High density plasma damage in InGaP/GaAs as AlGaAs/GaAs high electron mobility transistors

    SciTech Connect (OSTI)

    Lee, J.W.; Pearton, S.J. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; Ren, F.; Kopf, R.F.; Kuo, J.M. [Bell Labs., Murray Hill, NJ (United States). Lucent Technologies; Shul, R.J. [Sandia National Labs., Albuquerque, NM (United States); Constantine, C.; Johnson, D. [Plasma-Therm Inc., St. Petersburg, FL (United States)

    1998-11-01T23:59:59.000Z

    The introduction of plasma damage in InGaP/GaAs and AlGaAs/GaAs high electron mobility transistors (HEMTs) has been investigated using both inductively coupled plasma and electron cyclotron resonance Ar discharges. The saturated drain-source current is found to be decreased through introduction of compensating deep levels into the InGaP or AlGaAs donor layer. The degradation of device performance is a strong function of ion energy and ion flux, and an advantage of both high density plasma tools is that ion energy can be reduced by increasing the plasma density. Increasing process pressure and source power, and decreasing radio-frequency chuck power produce the lowest amounts of plasma damage in HEMTs.

  10. Laser intensity effects in noncommutative QED

    E-Print Network [OSTI]

    Thomas Heinzl; Anton Ilderton; Mattias Marklund

    2010-02-17T23:59:59.000Z

    We discuss a two-fold extension of QED assuming the presence of strong external fields provided by an ultra-intense laser and noncommutativity of spacetime. While noncommutative effects leave the electron's intensity induced mass shift unchanged, the photons change significantly in character: they acquire a quasi-momentum that is no longer light-like. We study the consequences of this combined noncommutative strong-field effect for basic lepton-photon interactions.

  11. Vortex stabilized electron beam compressed fusion grade plasma

    SciTech Connect (OSTI)

    Hershcovitch, Ady [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-03-19T23:59:59.000Z

    Most inertial confinement fusion schemes are comprised of highly compressed dense plasmas. Those schemes involve short, extremely high power, short pulses of beams (lasers, particles) applied to lower density plasmas or solid pellets. An alternative approach could be to shoot an intense electron beam through very dense, atmospheric pressure, vortex stabilized plasma.

  12. Ionization heating in rare-gas clusters under intense XUV laser pulses

    SciTech Connect (OSTI)

    Arbeiter, Mathias; Fennel, Thomas [Institute of Physics, University of Rostock, D-18051 Rostock (Germany)

    2010-07-15T23:59:59.000Z

    The interaction of intense extreme ultraviolet (XUV) laser pulses ({lambda}=32 nm, I=10{sup 11}-10{sup 14} W/cm{sup 2}) with small rare-gas clusters (Ar{sub 147}) is studied by quasiclassical molecular dynamics simulations. Our analysis supports a very general picture of the charging and heating dynamics in finite samples under short-wavelength radiation that is of relevance for several applications of free-electron lasers. First, up to a certain photon flux, ionization proceeds as a series of direct photoemission events producing a jellium-like cluster potential and a characteristic plateau in the photoelectron spectrum as observed in Bostedt et al. [Phys. Rev. Lett. 100, 133401 (2008)]. Second, beyond the onset of photoelectron trapping, nanoplasma formation leads to evaporative electron emission with a characteristic thermal tail in the electron spectrum. A detailed analysis of this transition is presented. Third, in contrast to the behavior in the infrared or low vacuum ultraviolet range, the nanoplasma energy capture proceeds via ionization heating, i.e., inner photoionization of localized electrons, whereas collisional heating of conduction electrons is negligible up to high laser intensities. A direct consequence of the latter is a surprising evolution of the mean energy of emitted electrons as function of laser intensity.

  13. Ultra-high-contrast laser acceleration of relativistic electrons in solid targets

    E-Print Network [OSTI]

    Higginson, Drew Pitney

    2013-01-01T23:59:59.000Z

    P. Higginson, et al. , Ultra-High-Contrast Laser Rise-TimeTHE DISSERTATION Ultra-High-Contrast Laser Acceleration ofCALIFORNIA, SAN DIEGO Ultra-High-Contrast Laser Acceleration

  14. Characteristics of InGaP/InGaAs pseudomorphic high electron mobility transistors with triple delta-doped sheets

    SciTech Connect (OSTI)

    Chu, Kuei-Yi [National Cheng-Kung University, Institute of Microelectronics, Department of Electrical Engineering (China); Chiang, Meng-Hsueh, E-mail: mhchiang@niu.edu.tw; Cheng, Shiou-Ying, E-mail: sycheng@niu.edu.tw [National II an University, Department of Electronic Engineering (China); Liu, Wen-Chau [National Cheng-Kung University, Institute of Microelectronics, Department of Electrical Engineering (China)

    2012-02-15T23:59:59.000Z

    Fundamental and insightful characteristics of InGaP/InGaAs double channel pseudomorphic high electron mobility transistors (DCPHEMTs) with graded and uniform triple {delta}-doped sheets are coomprehensively studied and demonstrated. To gain physical insight, band diagrams, carrier densities, and direct current characteristics of devices are compared and investigated based on the 2D semiconductor simulator, Atlas. Due to uniform carrier distribution and high electron density in the double InGaAs channel, the DCPHEMT with graded triple {delta}-doped sheets exhibits better transport properties, higher and linear transconductance, and better drain current capability as compared with the uniformly triple {delta}-doped counterpart. The DCPHEMT with graded triple {delta}-doped structure is fabricated and tested, and the experimental data are found to be in good agreement with simulated results.

  15. 3-D readout-electronics packaging for high-bandwidth massively paralleled imager

    DOE Patents [OSTI]

    Kwiatkowski, Kris (Los Alamos, NM); Lyke, James (Albuquerque, NM)

    2007-12-18T23:59:59.000Z

    Dense, massively parallel signal processing electronics are co-packaged behind associated sensor pixels. Microchips containing a linear or bilinear arrangement of photo-sensors, together with associated complex electronics, are integrated into a simple 3-D structure (a "mirror cube"). An array of photo-sensitive cells are disposed on a stacked CMOS chip's surface at a 45.degree. angle from light reflecting mirror surfaces formed on a neighboring CMOS chip surface. Image processing electronics are held within the stacked CMOS chip layers. Electrical connections couple each of said stacked CMOS chip layers and a distribution grid, the connections for distributing power and signals to components associated with each stacked CSMO chip layer.

  16. Hydrogen production by high-temperature water splitting using electron-conducting membranes

    DOE Patents [OSTI]

    Lee, Tae H.; Wang, Shuangyan; Dorris, Stephen E.; Balachandran, Uthamalingam

    2004-04-27T23:59:59.000Z

    A device and method for separating water into hydrogen and oxygen is disclosed. A first substantially gas impervious solid electron-conducting membrane for selectively passing hydrogen is provided and spaced from a second substantially gas impervious solid electron-conducting membrane for selectively passing oxygen. When steam is passed between the two membranes at disassociation temperatures the hydrogen from the disassociation of steam selectively and continuously passes through the first membrane and oxygen selectively and continuously passes through the second membrane, thereby continuously driving the disassociation of steam producing hydrogen and oxygen.

  17. Concepts for ELIC - A High Luminosity CEBAF Based Electron-Light Ion Collider

    SciTech Connect (OSTI)

    Ya. Derbenev, A. Bogacz, G. Krafft, R. Li, L. Merminga, B. Yunn, Y. Zhang

    2006-09-01T23:59:59.000Z

    A CEBAF accelerator based electron-light ion collider (ELIC) of rest mass energy from 20 to 65 GeV and luminosity from 10^33 to 10^35 cm6-2s^-1 with both beams polarized is envisioned as a future upgrade to CEBAF. A two step upgrade scenario is under study: CEBAF accelerator-ring-ring scheme (CRR) as the first step, and a multi-turn ERL-ring as the second step, to attain a better electron emittance and maximum luminosity. In this paper we report results of our studies of the CRR version of ELIC.

  18. Electronic Structure of LaOFeP - a Different Type of High Temperature

    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:INEAWater UseC Supports -ElectronicElectronicSuperconductor

  19. High energy electron beam curing of epoxy resin systems incorporating cationic photoinitiators

    DOE Patents [OSTI]

    Janke, Christopher J. (Powell, TN); Lopata, Vincent J. (Manitoba, CA); Havens, Stephen J. (Knoxville, TN); Dorsey, George F. (Farragut, TN); Moulton, Richard J. (Lafayette, CA)

    1999-01-01T23:59:59.000Z

    A mixture of epoxy resins such as a semi-solid triglycidyl ether of tris (hydroxyphenyl) methane and a low viscosity bisphenol A glycidyl ether and a cationic photoinitiator such as a diaryliodonium salt is cured by irradiating with a dosage of electron beams from about 50 to about 150 kGy, forming a cross-linked epoxy resin polymer.

  20. Preparations for a high gradient inverse free electron laser experiment at Brookhaven national laboratory

    SciTech Connect (OSTI)

    Duris, J.; Li, R. K.; Musumeci, P.; Sakai, Y.; Threlkeld, E.; Williams, O.; Fedurin, M.; Kusche, K.; Pogorelsky, I.; Polyanskiy, M.; Yakimenko, V. [UCLA Department of Physics and Astronomy, Los Angeles, CA 90095 (United States); Accelerator Test Facility, Brookhaven National Laboratory, Upton, NY, 11973 (United States)

    2012-12-21T23:59:59.000Z

    Preparations for an inverse free electron laser experiment at Brookhaven National Laboratory's Accelerator Test Facilty are presented. Details of the experimental setup including beam and laser transport optics are first discussed. Next, the driving laser pulse structure is investigated and initial diagnostics are explored and compared to simulations. Finally, planned improvements to the experimental setup are discussed.

  1. High energy electron beam curing of epoxy resin systems incorporating cationic photoinitiators

    DOE Patents [OSTI]

    Janke, C.J.; Lopata, V.J.; Havens, S.J.; Dorsey, G.F.; Moulton, R.J.

    1999-03-02T23:59:59.000Z

    A mixture of epoxy resins such as a semi-solid triglycidyl ether of tris (hydroxyphenyl) methane and a low viscosity bisphenol A glycidyl ether and a cationic photoinitiator such as a diaryliodonium salt is cured by irradiating with a dosage of electron beams from about 50 to about 150 kGy, forming a cross-linked epoxy resin polymer.

  2. Anisotropy of effective electron masses in highly doped nonpolar GaN

    SciTech Connect (OSTI)

    Feneberg, Martin, E-mail: martin.feneberg@ovgu.de; Lange, Karsten; Lidig, Christian; Wieneke, Matthias; Witte, Hartmut; Bläsing, Jürgen; Dadgar, Armin; Krost, Alois; Goldhahn, Rüdiger [Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg (Germany)] [Institut für Experimentelle Physik, Otto-von-Guericke-Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg (Germany)

    2013-12-02T23:59:59.000Z

    The anisotropic effective electron masses in wurtzite GaN are determined by generalized infrared spectroscopic ellipsometry. Nonpolar (112{sup Ż}0) oriented thin films allow accessing both effective masses, m{sub ?}{sup *} and m{sub ?}{sup *}, by determining the screened plasma frequencies. A n-type doping range up to 1.7?×?10{sup 20}?cm{sup ?3} is investigated. The effective mass ratio m{sub ?}{sup *}/m{sub ?}{sup *} is obtained with highest accuracy and is found to be 1.11 independent on electron concentration up to 1.2?×?10{sup 20}?cm{sup ?3}. For higher electron concentrations, the conduction band non-parabolicity is mirrored in changes. Absolute values for effective electron masses depend on additional input of carrier concentrations determined by Hall effect measurements. We obtain m{sub ?}{sup *}=(0.239±0.004)m{sub 0} and m{sub ?}{sup *}=(0.216±0.003)m{sub 0} for the parabolic range of the GaN conduction band. Our data are indication of a parabolic GaN conduction band up to an energy of approximately 400?meV above the conduction band minimum.

  3. Mechanism and computational model for Lyman-{alpha}-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas

    SciTech Connect (OSTI)

    Louchev, Oleg A.; Saito, Norihito; Wada, Satoshi [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Bakule, Pavel [STFC, ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX (United Kingdom); Yokoyama, Koji [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Ishida, Katsuhiko; Iwasaki, Masahiko [Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan)

    2011-09-15T23:59:59.000Z

    We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-{alpha} (Ly-{alpha}) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-{alpha} generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-{alpha} radiation generation can achieve a value of {approx}5x10{sup -4} which is restricted by the total combined absorption of the fundamental and generated radiation.

  4. Connecting Renewables Directly to the Grid: Resilient Multi-Terminal HVDC Networks with High-Voltage High-Frequency Electronics

    SciTech Connect (OSTI)

    None

    2012-01-23T23:59:59.000Z

    GENI Project: GE is developing electricity transmission hardware that could connect distributed renewable energy sources, like wind farms, directly to the grid—eliminating the need to feed the energy generated through intermediate power conversion stations before they enter the grid. GE is using the advanced semiconductor material silicon carbide (SiC) to conduct electricity through its transmission hardware because SiC can operate at higher voltage levels than semiconductors made out of other materials. This high-voltage capability is important because electricity must be converted to high-voltage levels before it can be sent along the grid’s network of transmission lines. Power companies do this because less electricity is lost along the lines when the voltage is high.

  5. Light intensity compressor

    DOE Patents [OSTI]

    Rushford, Michael C. (Livermore, CA)

    1990-01-01T23:59:59.000Z

    In a system for recording images having vastly differing light intensities over the face of the image, a light intensity compressor is provided that utilizes the properties of twisted nematic liquid crystals to compress the image intensity. A photoconductor or photodiode material that is responsive to the wavelength of radiation being recorded is placed adjacent a layer of twisted nematic liquid crystal material. An electric potential applied to a pair of electrodes that are disposed outside of the liquid crystal/photoconductor arrangement to provide an electric field in the vicinity of the liquid crystal material. The electrodes are substantially transparent to the form of radiation being recorded. A pair of crossed polarizers are provided on opposite sides of the liquid crystal. The front polarizer linearly polarizes the light, while the back polarizer cooperates with the front polarizer and the liquid crystal material to compress the intensity of a viewed scene. Light incident upon the intensity compressor activates the photoconductor in proportion to the intensity of the light, thereby varying the field applied to the liquid crystal. The increased field causes the liquid crystal to have less of a twisting effect on the incident linearly polarized light, which will cause an increased percentage of the light to be absorbed by the back polarizer. The intensity of an image may be compressed by forming an image on the light intensity compressor.

  6. Mechanism of 'GSI oscillations' in electron capture by highly charged hydrogen-like atomic ions

    SciTech Connect (OSTI)

    Krainov, V. P., E-mail: vpkrainov@mail.ru [Moscow Institute of Physics and Technology (Russian Federation)

    2012-07-15T23:59:59.000Z

    We suggest a qualitative explanation of oscillations in electron capture decays of hydrogen-like {sup 140}Pr and {sup 142}Pm ions observed recently in an ion experimental storage ring (ESR) of Gesellschaft fuer Schwerionenforschung (GSI) mbH, Darmstadt, Germany. This explanation is based on the electron multiphoton Rabi oscillations between two Zeeman states of the hyperfine ground level with the total angular momentum F = 1/2. The Zeeman splitting is produced by a constant magnetic field in the ESR. Transitions between these states are produced by the second, sufficiently strong alternating magnetic field that approximates realistic fields in the GSI ESR. The Zeeman splitting amounts to only about 10{sup -5} eV. This allows explaining the observed quantum beats with the period 7 s.

  7. Pulse shapes from electron and photon induced events in segmented high-purity germanium detectors

    E-Print Network [OSTI]

    I. Abt; A. Caldwell; K. Kröninger; J. Liu; X. Liu; B. Majorovits

    2007-04-23T23:59:59.000Z

    Experiments built to search for neutrinoless double beta-decay are limited in their sensitivity not only by the exposure but also by the amount of background encountered. Radioactive isotopes in the surrounding of the detectors which emit gamma-radiation are expected to be a significant source of background in the GERmanium Detector Array, GERDA. Methods to select electron induced events and discriminate against photon induced events inside a germanium detector are presented in this paper. The methods are based on the analysis of the time structure of the detector response. Data were taken with a segmented GERDA prototype detector. It is shown that the analysis of the time response of the detector can be used to distinguish multiply scattered photons from electrons.

  8. Hydrogen production by high temperature water splitting using electron conducting membranes

    DOE Patents [OSTI]

    Balachandran, Uthamalingam; Wang, Shuangyan; Dorris, Stephen E.; Lee, Tae H.

    2006-08-08T23:59:59.000Z

    A device and method for separating water into hydrogen and oxygen is disclosed. A first substantially gas impervious solid electron-conducting membrane for selectively passing protons or hydrogen is provided and spaced from a second substantially gas impervious solid electron-conducting membrane for selectively passing oxygen. When steam is passed between the two membranes at dissociation temperatures the hydrogen from the dissociation of steam selectively and continuously passes through the first membrane and oxygen selectively and continuously passes through the second membrane, thereby continuously driving the dissociation of steam producing hydrogen and oxygen. The oxygen is thereafter reacted with methane to produce syngas which optimally may be reacted in a water gas shift reaction to produce CO2 and H2.

  9. Recent Progress in Chromatic Aberration Corrected High-Resolution and Lorentz Transmission Electron Microscopy

    E-Print Network [OSTI]

    Dunin-Borkowski, Rafal E.

    80 and 65 pm detail at 80 and 300 kV, respectively. Figure 2 shows CC and CS corrected energy. 58 (2009) 147. [3] R. Leary and R. Brydson. Advances in Imaging and Electron Physics 165 (2011) 73. The smallest detected image spacing at 80 kV (left) is ~80 pm and at 300 kV (right) is ~65 pm. FIG. 2. Atomic

  10. Electron beam melting at high pressures with a vacuum separator/plasma lens

    SciTech Connect (OSTI)

    Hershcovitch, A. [Brookhaven National Laboratory, Upton, NY (United States)

    1995-12-31T23:59:59.000Z

    Plasmas can be used to provide a vacuum-atmosphere interface or separation between vacua regions as an alternative to differential pumping. Vacuum-atmosphere interface utilizing a cascade arc discharge was successfully propagated from vacuum through such a plasma interface and out into atmospheric pressure. This plasma device also functions as an effective plasma lens. Such a device can be adopted for use in electron beam melting.

  11. A 25 KV/10A PULSER FOR DRIVING A HIGH-POWER PIERCE ELECTRON GUN

    E-Print Network [OSTI]

    of short-circuits. Since the current capability of the tetrode is of the order of 10 A in the case of a short-circuit, the limit of the charging voltage is up to a maximum of 25 kV. The pulsed system has.0 A current and 10.0 kV beam voltage. Key words hard-tube pulser, Pierce electron gun, microwave tube

  12. HIGH CURRENT AND HIGH BRIGHTNESS ELECTRON SOURCES , I. Bazarov, S. Belomestnykh, M. Billing, E. Chojnacki, Z. Conway,

    E-Print Network [OSTI]

    Gruner, Sol M.

    will review the technical requirements of such projects and the status of on-going research through- out and longitudinally shaped laser pulse, in RF cavities with very high electrical fields of up to 120 MV/m [1] to beam to a significant heating of the cavity surfaces due to resistive energy losses which causes thermal stress

  13. Evidence of High Harmonics from Echo-Enabled Harmonic Generation for Seeding X-ray Free Electron Lasers

    SciTech Connect (OSTI)

    Xiang, D.; Colby, E.; Dunning, M.; Gilevich, S.; Hast, C.; Jobe, K.; McCormick, D.; Nelson, J.; Raubenheimer, T.O.; Soong, K.; Stupakov, G.; Szalata, Z.; Walz, D.; Weathersby, S.; Woodle, M.; /SLAC; ,

    2012-02-15T23:59:59.000Z

    Echo-enabled harmonic generation free electron lasers hold great promise for the generation of fully coherent radiation in x-ray wavelengths. Here we report the first evidence of high harmonics from the echo-enabled harmonic generation technique in the realistic scenario where the laser energy modulation is comparable to the beam slice energy spread. In this experiment, coherent radiation at the seventh harmonic of the second seed laser is generated when the energy modulation amplitude is about 2-3 times the slice energy spread. The experiment confirms the underlying physics of echo-enabled harmonic generation and may have a strong impact on emerging seeded x-ray free electron lasers that are capable of generating laserlike x rays which will advance many areas of science.

  14. Electron density and currents of AlN/GaN high electron mobility transistors with thin GaN/AlN buffer layer

    SciTech Connect (OSTI)

    Bairamis, A.; Zervos, Ch.; Georgakilas, A., E-mail: alexandr@physics.uoc.gr [Microelectronics Research Group, IESL, Foundation for Research and Technology-Hellas (FORTH), P.O. Box 1385, GR-71110 Heraklion, Crete (Greece); Department of Physics, University of Crete, P.O. Box 2208, GR-71003 Heraklion, Crete (Greece); Adikimenakis, A.; Kostopoulos, A.; Kayambaki, M.; Tsagaraki, K.; Konstantinidis, G. [Microelectronics Research Group, IESL, Foundation for Research and Technology-Hellas (FORTH), P.O. Box 1385, GR-71110 Heraklion, Crete (Greece)

    2014-09-15T23:59:59.000Z

    AlN/GaN high electron mobility transistor (HEMT) structures with thin GaN/AlN buffer layer have been analyzed theoretically and experimentally, and the effects of the AlN barrier and GaN buffer layer thicknesses on two-dimensional electron gas (2DEG) density and transport properties have been evaluated. HEMT structures consisting of [300?nm GaN/ 200?nm AlN] buffer layer on sapphire were grown by plasma-assisted molecular beam epitaxy and exhibited a remarkable agreement with the theoretical calculations, suggesting a negligible influence of the crystalline defects that increase near the heteroepitaxial interface. The 2DEG density varied from 6.8?×?10{sup 12} to 2.1 × 10{sup 13} cm{sup ?2} as the AlN barrier thickness increased from 2.2 to 4.5?nm, while a 4.5?nm AlN barrier would result to 3.1?×?10{sup 13} cm{sup ?2} on a GaN buffer layer. The 3.0?nm AlN barrier structure exhibited the highest 2DEG mobility of 900?cm{sup 2}/Vs for a density of 1.3?×?10{sup 13} cm{sup ?2}. The results were also confirmed by the performance of 1??m gate-length transistors. The scaling of AlN barrier thickness from 1.5?nm to 4.5?nm could modify the drain-source saturation current, for zero gate-source voltage, from zero (normally off condition) to 0.63?A/mm. The maximum drain-source current was 1.1?A/mm for AlN barrier thickness of 3.0?nm and 3.7?nm, and the maximum extrinsic transconductance was 320 mS/mm for 3.0?nm AlN barrier.

  15. Intense Femtosecond Laser Interactions with Ions in

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    ), ultra-short laser light with atoms and molecules has led to the discovery of new phenomena such as bondIntense Femtosecond Laser Interactions with Ions in Beams and Traps A thesis presented through a re-scattering process where an electron is ionized, propagated in the laser field and is driven

  16. Vehicle Technologies Office Merit Review 2014: High-Temperature Air-Cooled Power Electronics Thermal Design

    Broader source: Energy.gov [DOE]

    Presentation given by National Renewable Energy Laboratory at 2014 DOE Hydrogen and Fuel Cells Program and Vehicle Technologies Office Annual Merit Review and Peer Evaluation Meeting about high...

  17. Experimental study of high energy electron interactions in a superconducting aluminum alloy resonant bar

    E-Print Network [OSTI]

    M. Barucci; M. Bassan; B. Buonomo; G. Cavallari; E. Coccia; S. D'Antonio; V. Fafone; C. Ligi; L. Lolli; A. Marini; G. Mazzitelli; G. Modestino; G. Pizzella; L. Quintieri; L. Risegari; A. Rocchi; F. Ronga; P. Valente; G. Ventura; S. M. Vinko

    2009-01-09T23:59:59.000Z

    Peak amplitude measurements of the fundamental mode of oscillation of a suspended aluminum alloy bar hit by an electron beam show that the amplitude is enhanced by a factor ~3.5 when the material is in the superconducting state. This result is consistent with the cosmic ray observations made by the resonant gravitational wave detector NAUTILUS, made of the same alloy, when operated in the superconducting state. A comparison of the experimental data with the predictions of the model describing the underlying physical process is also presented.

  18. Performance of a Tungsten-Cerium Fluoride Sampling Calorimeter in High-Energy Electron Beam Tests

    E-Print Network [OSTI]

    Becker, R; Dissertori, G; Djambazov, L; Donegŕ, M; Lustermann, W; Marini, A C; Nessi-Tedaldi, F; Pandolfi, F; Peruzzi, M; Schönenberger, M; Cavallari, F; Dafinei, I; Diemoz, M; Lope, C Jorda; Meridiani, P; Nuccetelli, M; Paramatti, R; Pellegrino, F; Micheli, F; Organtini, G; Rahatlou, S; Soffi, L; Brianza, L; Govoni, P; Martelli, A; de Fatis, T Tabarelli; Monti, V; Pastrone, N; Trapani, P P; Candelise, V; Della Ricca, G

    2015-01-01T23:59:59.000Z

    A prototype for a sampling calorimeter made out of cerium fluoride crystals interleaved with tungsten plates, and read out by wavelength-shifting fibres, has been exposed to beams of electrons with energies between 20 and 150 GeV, produced by the CERN Super Proton Synchrotron accelerator complex. The performance of the prototype is presented and compared to that of a Geant4 simulation of the apparatus. Particular emphasis is given to the response uniformity across the channel front face, and to the prototype's energy resolution.

  19. Method of forming a dense, high temperature electronically conductive composite layer on a porous ceramic substrate

    DOE Patents [OSTI]

    Isenberg, A.O.

    1992-04-21T23:59:59.000Z

    An electrochemical device, containing a solid oxide electrolyte material and an electrically conductive composite layer, has the composite layer attached by: (A) applying a layer of LaCrO[sub 3], YCrO[sub 3] or LaMnO[sub 3] particles, on a portion of a porous ceramic substrate, (B) heating to sinter bond the particles to the substrate, (C) depositing a dense filler structure between the doped particles, (D) shaving off the top of the particles, and (E) applying an electronically conductive layer over the particles as a contact. 7 figs.

  20. The Intense Radiation Gas

    E-Print Network [OSTI]

    M. Marklund; P. K. Shukla; B. Eliasson

    2005-03-08T23:59:59.000Z

    We present a new dispersion relation for photons that are nonlinearly interacting with a radiation gas of arbitrary intensity due to photon-photon scattering. It is found that the photon phase velocity decreases with increasing radiation intensity, it and attains a minimum value in the limit of super-intense fields. By using Hamilton's ray equations, a self-consistent kinetic theory for interacting photons is formulated. The interaction between an electromagnetic pulse and the radiation gas is shown to produce pulse self-compression and nonlinear saturation. Implications of our new results are discussed.

  1. Computational phase imaging based on intensity transport

    E-Print Network [OSTI]

    Waller, Laura A. (Laura Ann)

    2010-01-01T23:59:59.000Z

    Light is a wave, having both an amplitude and a phase. However, optical frequencies are too high to allow direct detection of phase; thus, our eyes and cameras see only real values - intensity. Phase carries important ...

  2. Building dependability arguments for software intensive systems

    E-Print Network [OSTI]

    Seater, Robert Morrison

    2009-01-01T23:59:59.000Z

    A method is introduced for structuring and guiding the development of end-to-end dependability arguments. The goal is to establish high-level requirements of complex software-intensive systems, especially properties that ...

  3. On the relation between electron temperatures in the O+ and O++ zones in high-metallicity HII regions

    E-Print Network [OSTI]

    L. S. Pilyugin; J. M. Vilchez; T. X. Thuan

    2006-05-29T23:59:59.000Z

    We suggest a new way to establish the relation between the electron temperature t3 within the [OIII] zone and the electron temperature t2 within the [OII] zone in high-metallicity (12+log(O/H) > 8.25) HII regions. The t2 - t3 diagram is constructed by applying our method to a sample of 372 HII regions. We find that the correlation between t2 and t3 is tight and can be approximated by a linear expression. The new t2 - t3 relation can be used to determine t2 and accurate abundances in high-metallicity HII regions with a measured t3. It can also be used in conjunction with the ff relation for the determination of t3 and t2 and oxygen abundances in high-metallicity HII regions where the [OIII]4363 auroral line is not detected. The derived t2 - t3 relation is independent of photoionization models of HII regions.

  4. HIGH VOLTAGE TERMINAL IN COSY ELECTRON COOLER V.A. Chekavinskiy, E.A. Bekhtenev, I.A. Gusev, M.N. Kondaurov, V.R. Kozak, E.A. Kuper, V.R.

    E-Print Network [OSTI]

    Kozak, Victor R.

    HIGH VOLTAGE TERMINAL IN COSY ELECTRON COOLER V.A. Chekavinskiy, E.A. Bekhtenev, I.A. Gusev, M acceleration system ­ high voltage terminal. All power and control electronics were placed in a single isolated Voltage Terminal (HVT) in electron cooler is intended for generating of electron cooling beam

  5. J. Phys III FFance 7 (1997) 1451-1467 JULY 1997, PAGE 1451 High Resolution Electron Microscopic Studies of the Atomistic

    E-Print Network [OSTI]

    Boyer, Edmond

    of Engineering, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo l13, Japan (~) Institute for Solid State Physics Mechanical properties of solids PACS.61.18.-j Other methods of structure determination Abstract. Direct attempted by using high resolution electron microscopy with the electron beam incident normal

  6. Existence domains of arbitrary amplitude nonlinear structures in two-electron temperature space plasmas. II. High-frequency electron-acoustic solitons

    SciTech Connect (OSTI)

    Maharaj, S. K. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200 (South Africa); Bharuthram, R. [University of the Western Cape, Modderdam Road, Bellville 7530 (South Africa); Singh, S. V. [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India); School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag X54001, Durban 4000 (South Africa); Lakhina, G. S. [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India)

    2012-12-15T23:59:59.000Z

    A three-component plasma model composed of ions, cool electrons, and hot electrons is adopted to investigate the existence of large amplitude electron-acoustic solitons not only for the model for which inertia and pressure are retained for all plasma species which are assumed to be adiabatic but also neglecting inertial effects of the hot electrons. Using the Sagdeev potential formalism, the Mach number ranges supporting the existence of large amplitude electron-acoustic solitons are presented. The limitations on the attainable amplitudes of electron-acoustic solitons having negative potentials are attributed to a number of different physical reasons, such as the number density of either the cool electrons or hot electrons ceases to be real valued beyond the upper Mach number limit, or, alternatively, a negative potential double layer occurs. Electron-acoustic solitons having positive potentials are found to be supported only if inertial effects of the hot electrons are retained and these are found to be limited only by positive potential double layers.

  7. In-situ stoichiometry determination using x-ray fluorescence generated by reflection-high-energy-electron-diffraction

    SciTech Connect (OSTI)

    Keenan, Cameron; Chandril, Sandeep; Lederman, David [Department of Physics and Multifunctional Materials Laboratory, West Virginia University, Morgantown, West Virginia 26506 (United States); Myers, T. H. [Department of Physics and Multifunctional Materials Laboratory, West Virginia University, Morgantown, West Virginia 26506 (United States); Materials Science, Engineering, and Commercialization Program, Texas State University-San Marcos, San Marcos, Texas 78666 (United States)

    2011-06-01T23:59:59.000Z

    A major challenge in the stoichiometric growth of complex oxide compounds is the control of the relative compositions of the constituent materials. A potential avenue for compositional analysis during growth is the use of x-ray fluorescence generated during reflection high energy electron diffraction measurements. Using this technique, relative compositions of Y and Mn in molecular beam epitaxy grown YMnO{sub 3} samples were studied. Comparing the results with Rutherford back scattering spectroscopy suggests that the technique has the potential for real-time analysis of elemental fluxes and stoichiometry control during sample growth.

  8. High temperature electron spin dynamics in bulk cubic GaN: Nanosecond spin lifetimes far above room-temperature

    SciTech Connect (OSTI)

    Buß, J. H.; Schaefer, A.; Hägele, D.; Rudolph, J. [Arbeitsgruppe Spektroskopie der kondensierten Materie, Ruhr-Universität Bochum, Universitätsstraße 150, D-44780 Bochum (Germany); Schupp, T.; As, D. J. [Department of Physics, University of Paderborn, Warburger Str. 100, D-33095 Paderborn (Germany)

    2014-11-03T23:59:59.000Z

    The electron spin dynamics in n-doped bulk cubic GaN is investigated for very high temperatures from 293?K up to 500?K by time-resolved Kerr-rotation spectroscopy. We find extraordinarily long spin lifetimes exceeding 1?ns at 500?K. The temperature dependence of the spin relaxation time is in qualitative agreement with predictions of Dyakonov-Perel theory, while the absolute experimental times are an order of magnitude shorter than predicted. Possible reasons for this discrepancy are discussed, including the role of phase mixtures of hexagonal and cubic GaN as well as the impact of localized carriers.

  9. Solar radiation intensity calculations

    E-Print Network [OSTI]

    Levine, Randolph Steven

    1978-01-01T23:59:59.000Z

    SOLAR RADIATION INTENSITY CALCULATIONS A Thesis by RANDOLPH STEVEN LEVINE Submitted to the Graduate College of Texas A&M University in partia'l fulfillment of the requirement for the degree of MASTER OF SCIENCE December 1978 Major Subject...: Physics SOLAR RADIATION INTENSITY CALCULATIONS A Thesis by RANDOLPH STEVEN LEVINE Approved as to style and content by: (Chairman of Committee) (Member) (Member) ( member) (Head of Department) December 1978 f219 037 ABSTRACT Solar Radiation...

  10. Design of a miniature high-speed carbon-nanotube-enhanced ultracapacitor for electronics applications

    E-Print Network [OSTI]

    D'Asaro, Matthew E. (Matthew Eric)

    2012-01-01T23:59:59.000Z

    Electrolytic capacitors, the current standard for high-value capacitors, are one of the most challenging components to miniaturize, accounting for up to 1/3 of the volume in some power devices, and are the weak link with ...

  11. IDENTIFICATION AND CONTROL METHODS FOR HIGH POWER ELECTRON BEAM-DRIVEN MICROWAVE TUBES

    E-Print Network [OSTI]

    concepts to the field of high power microwave (HPM) tubes. These concepts are well known to the control systems community, but have not yet been fully exploited within the HPM community. The simpler

  12. Nickel-Catalyzed Mizoroki-Heck Reaction of Aryl Sulfonates and Chlorides with Electronically Unbiased Terminal Olefins: High Selectivity for Branched Products

    E-Print Network [OSTI]

    Tasker, Sarah Z.

    Achieving high selectivity in the Heck reaction of electronically unbiased alkenes has been a longstanding challenge. Using a nickel-catalyzed cationic Heck reaction, we were able to achieve excellent selectivity for ...

  13. Development of hollow electron beams for proton and ion collimation

    SciTech Connect (OSTI)

    Stancari, G.; Drozhdin, A.I.; Kuznetsov, G.; Shiltsev, V.; Still, D.A.; Valishev, A.; Vorobiev, L.G.; /Fermilab; Assmann, R.; /CERN; Kabantsev, A.; /UC, San Diego

    2010-06-01T23:59:59.000Z

    Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable material damage. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and built. Its performance and stability were measured at the Fermilab test stand. The gun will be installed in one of the existing Tevatron electron lenses for preliminary tests of the hollow-beam collimator concept, addressing critical issues such as alignment and instabilities of the overlapping proton and electron beams.

  14. High-power rf-pulsed modulators for the Los Alamos free-electron laser

    SciTech Connect (OSTI)

    Johnson, W.J.D.; Lynch, M.T.; Tallerico, P.J.; Keffeler, D.R.; Hornkohl, J.O.

    1987-09-01T23:59:59.000Z

    In the rf-driven free-electron laser (FEL) at the Los Alamos National Laboratory, there are two pulsed-power rf modulators as sources for two tandem, side-coupled 20-MeV linear accelerators. The rf power used to control the cavity fields is supplied by two 5.5-MW modulating anode klystrons operating at a center frequency of 1300.2 MHz. The modulation of the 125 kV klystron is achieved by using a triode switch tube that provides a pulse width up to 300 ..mu..s and a pulse repetition rate up to 10 Hz. This paper describes the present configuration of these two duplicate systems and presents plans for meeting the requirements of future rf FEL experiments at Los Alamos. 12 refs., 5 figs.

  15. Status report on Jefferson Lab`s high-power infrared free-electron laser

    SciTech Connect (OSTI)

    Bohn, C.L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    1997-10-01T23:59:59.000Z

    Jefferson Lab is building a free-electron laser to produce tunable, continuous-wave (cw), kW-level light at 3-6 {mu}m wavelength. A superconducting accelerator will drive the laser, and a transport lattice will recirculate the beam back through the accelerator for energy recovery. Space charge in the injector and coherent synchrotron radiation in magnetic bends will be present, and the machine is instrumented to study these phenomena during commissioning. The wiggler and optical cavity are conventional; however, significant analysis and testing was needed to ensure mirror heating at 1 kW of outcoupled power would not impede performance. The FEL is being installed in its own facility, and installation will be finished in Fall 1997. This paper surveys the machine, the status of its construction, and plans for its commissioning.

  16. Preparation of high purity niobium by electron beam melting and external gettering

    SciTech Connect (OSTI)

    Kim, Yong Hwan; Suzuki, Ryosuke O.; Ono, Katsutoshi [Kyoto Univ., Yoshida-Honmachi (Japan)

    1994-12-31T23:59:59.000Z

    Physical properties of niobium are deteriorated by interstitial impurities such as oxygen and nitrogen. The removal of these gaseous impurities was studied by electron beam (EB) melting and solid state external gettering with Ti, Y and Zr. The buttons and ingots were repeatedly remelted and refined by the EB furnace (max.; l4OkW). Subsequently, the external gettering for oxygen and nitrogen in niobium was carried out by wrapping samples with active metal foils and annealing in evacuated quartz ampoules over 1273K. The purity of refined niobium was characterized by its hardness, specific resistivity, internal friction and residual resistivity ratio (RRR={rho}{sub 273}/{rho}{sub 4.2}). The results of these measurements were compared with conventional gas analysis. Niobium was purified to the RRR of 100 through EB melting and 700 through external gettering.

  17. 2546 IEEE 1`RANSACTIONS ON ELECTRON DEVICES, VOL. ED-32, NO. 11, NOVEMBER 1985 their high-current drivability. However, their structure is so tom-

    E-Print Network [OSTI]

    Woodall, Jerry M.

    2546 IEEE 1`RANSACTIONS ON ELECTRON DEVICES, VOL. ED-32, NO. 11, NOVEMBER 1985 their high-current drivability. However, their structure is so tom- plicated that it is difficult to fabricate fine devices and high-deltsity IC's. This paper reports a new high-speed device utilizing a 21XEG heterostrucure, which

  18. Effect of Electron-Electron Interaction on Transport in Dye-Sensitized Nanocrystalline TiO2

    SciTech Connect (OSTI)

    van de Lagemaat, J.; Kopidakis, N.; Neale, N. R.; Frank, A. J.

    2005-01-01T23:59:59.000Z

    Experimental measurements and continuous-time random walk simulations on sensitized electrolyte-infused porous nanocrystalline TiO2 films show that the actual electronic charge in the films is significantly larger than that estimated from small-perturbation methods by a constant, light-intensity-independent factor. This observation can be explained by small-perturbation techniques measuring the chemical diffusion coefficient of electrons instead of the normally assumed tracer diffusion coefficient of electrons. The difference between the two diffusion coefficients is attributed to the presence of an exponential density of states through which electrons interact. At high light intensities, an additional extra component owing to Coulomb interactions between the electrons is expected to arise.

  19. High-brightness X-ray free-electron laser with an optical undulator by pulse shaping

    E-Print Network [OSTI]

    2013-01-01T23:59:59.000Z

    codes: (140.2600) Free-electron lasers (FELs); (140.3300)The Development of X-Ray Free-Electron Lasers,” IEEE J. Sel.and M.N. Rosenbluth, “Free-Electron Lasers with Variable

  20. Reduced thermal resistance in AlGaN/GaN multi-mesa-channel high electron mobility transistors

    SciTech Connect (OSTI)

    Asubar, Joel T., E-mail: joel@rciqe.hokudai.ac.jp; Yatabe, Zenji; Hashizume, Tamotsu [Research Center for Integrated Quantum Electronics (RCIQE) and Graduate School of Information Science and Technology, Hokkaido University, Sapporo (Japan); Japan Science and Technology Agency (JST), CREST, 102-0075 Tokyo (Japan)

    2014-08-04T23:59:59.000Z

    Dramatic reduction of thermal resistance was achieved in AlGaN/GaN Multi-Mesa-Channel (MMC) high electron mobility transistors (HEMTs) on sapphire substrates. Compared with the conventional planar device, the MMC HEMT exhibits much less negative slope of the I{sub D}-V{sub DS} curves at high V{sub DS} regime, indicating less self-heating. Using a method proposed by Menozzi and co-workers, we obtained a thermal resistance of 4.8?K-mm/W at ambient temperature of ?350?K and power dissipation of ?9?W/mm. This value compares well to 4.1?K-mm/W, which is the thermal resistance of AlGaN/GaN HEMTs on expensive single crystal diamond substrates and the lowest reported value in literature.

  1. Electronic couplings for molecular charge transfer: Benchmarking CDFT, FODFT, and FODFTB against high-level ab initio calculations

    SciTech Connect (OSTI)

    Kubas, Adam; Blumberger, Jochen, E-mail: j.blumberger@ucl.ac.uk [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)] [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Hoffmann, Felix [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom) [Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Universitätsstr. 150, 44801 Bochum (Germany); Heck, Alexander; Elstner, Marcus [Institute of Physical Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany)] [Institute of Physical Chemistry, Karlsruhe Institute of Technology, Fritz-Haber-Weg 6, 76131 Karlsruhe (Germany); Oberhofer, Harald [Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85747 Garching (Germany)] [Department of Chemistry, Technical University of Munich, Lichtenbergstr. 4, 85747 Garching (Germany)

    2014-03-14T23:59:59.000Z

    We introduce a database (HAB11) of electronic coupling matrix elements (H{sub ab}) for electron transfer in 11 ?-conjugated organic homo-dimer cations. High-level ab inito calculations at the multireference configuration interaction MRCI+Q level of theory, n-electron valence state perturbation theory NEVPT2, and (spin-component scaled) approximate coupled cluster model (SCS)-CC2 are reported for this database to assess the performance of three DFT methods of decreasing computational cost, including constrained density functional theory (CDFT), fragment-orbital DFT (FODFT), and self-consistent charge density functional tight-binding (FODFTB). We find that the CDFT approach in combination with a modified PBE functional containing 50% Hartree-Fock exchange gives best results for absolute H{sub ab} values (mean relative unsigned error = 5.3%) and exponential distance decay constants ? (4.3%). CDFT in combination with pure PBE overestimates couplings by 38.7% due to a too diffuse excess charge distribution, whereas the economic FODFT and highly cost-effective FODFTB methods underestimate couplings by 37.6% and 42.4%, respectively, due to neglect of interaction between donor and acceptor. The errors are systematic, however, and can be significantly reduced by applying a uniform scaling factor for each method. Applications to dimers outside the database, specifically rotated thiophene dimers and larger acenes up to pentacene, suggests that the same scaling procedure significantly improves the FODFT and FODFTB results for larger ?-conjugated systems relevant to organic semiconductors and DNA.

  2. Compact and high-particle-flux thermal-lithium-beam probe system for measurement of two-dimensional electron density profile

    SciTech Connect (OSTI)

    Shibata, Y., E-mail: shibata.yoshihide@jaea.go.jp; Manabe, T.; Ohno, N.; Takagi, M. [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Kajita, S. [EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8603 (Japan); Tsuchiya, H.; Morisaki, T. [National Institute for Fusion Science, Oroshi, Toki, Gifu 509-5292 (Japan)

    2014-09-15T23:59:59.000Z

    A compact and high-particle-flux thermal-lithium-beam source for two-dimensional measurement of electron density profiles has been developed. The thermal-lithium-beam oven is heated by a carbon heater. In this system, the maximum particle flux of the thermal lithium beam was ?4 × 10{sup 19} m{sup ?2} s{sup ?1} when the temperature of the thermal-lithium-beam oven was 900 K. The electron density profile was evaluated in the small tokamak device HYBTOK-II. The electron density profile was reconstructed using the thermal-lithium-beam probe data and this profile was consistent with the electron density profile measured with a Langmuir electrostatic probe. We confirm that the developed thermal-lithium-beam probe can be used to measure the two-dimensional electron density profile with high time and spatial resolutions.

  3. High resolution low dose transmission electron microscopy real-time imaging and manipulation of nano-scale objects in the electron beam

    DOE Patents [OSTI]

    Brown, Jr., R. Malcolm (Austin, TX); Barnes, Zack (Austin, TX); Sawatari, Chie (Shizuoka, JP); Kondo, Tetsuo (Kukuoka, JP)

    2008-02-26T23:59:59.000Z

    The present invention includes a method, apparatus and system for nanofabrication in which one or more target molecules are identified for manipulation with an electron beam and the one or more target molecules are manipulated with the electron beam to produce new useful materials.

  4. Enhancement of the helium resonance lines in the solar atmosphere by suprathermal electron excitation II: non-Maxwellian electron distributions

    E-Print Network [OSTI]

    G. R. Smith

    2003-06-20T23:59:59.000Z

    In solar EUV spectra the He I and He II resonance lines show unusual behaviour and have anomalously high intensities compared with other transition region lines. The formation of the helium resonance lines is investigated through extensive non-LTE radiative transfer calculations. The model atmospheres of Vernazza, Avrett & Loeser are found to provide reasonable matches to the helium resonance line intensities but significantly over-estimate the intensities of other transition region lines. New model atmospheres have been developed from emission measure distributions derived by Macpherson & Jordan, which are consistent with SOHO observations of transition region lines other than those of helium. These models fail to reproduce the observed helium resonance line intensities by significant factors. The possibility that non-Maxwellian electron distributions in the transition region might lead to increased collisional excitation rates in the helium lines is studied. Collisional excitation and ionization rates are re-computed for distribution functions with power law suprathermal tails which may form by the transport of fast electrons from high temperature regions. Enhancements of the helium resonance line intensities are found, but many of the predictions of the models regarding line ratios are inconsistent with observations. These results suggest that any such departures from Maxwellian electron distributions are not responsible for the helium resonance line intensities.

  5. High-frequency microstrip cross resonators for circular polarization electron paramagnetic resonance spectroscopy

    E-Print Network [OSTI]

    del Barco, Enrique

    resonators, designed to match the 50 impedance of the lines on a high dielectric constant GaAs substrate excitation at the center of the cross resonator. The third output port is used to measure the transmitted resonator, composed of two half- wavelength microstrip line resonators which allow an in situ and all

  6. Proceedings of the seventh international conference on high voltage electron microscopy

    SciTech Connect (OSTI)

    Fisher, R.M.; Gronsky, R.; Westmacott, K.H. (eds.)

    1983-01-01T23:59:59.000Z

    Eight-four papers are arranged under the following headings: high resolution, techniques and instrumentation, radiation effects, in-situ and phase transformations, minerals and ceramics, and semiconductors and thin films. Twenty-three papers were abstracted separately for the data base; three of the remainder had previously been abstracted. (DLC)

  7. Studies of Charge Exchange in a High?Pressure Pulsed Electron Impact Source

    E-Print Network [OSTI]

    Sharma, D. K. Sen; Hierl, Peter M.; Franklin, J. L.

    1972-01-01T23:59:59.000Z

    A high pressure pulsed ion source has been used in a time?of?flight mass spectrometer in order to study the charge exchangereactions in Ar–H2 and Ar–D2 systems using the ion source in the ?ermák mode of operation. As the source was used in a pulsed...

  8. High speed preamplifier circuit, detection electronics, and radiation detection systems therefrom

    DOE Patents [OSTI]

    Riedel, Richard A. (Knoxville, TN) [Knoxville, TN; Wintenberg, Alan L. (Knoxville, TN) [Knoxville, TN; Clonts, Lloyd G. (Knoxville, TN) [Knoxville, TN; Cooper, Ronald G [Oak Ridge, TN

    2010-09-21T23:59:59.000Z

    A preamplifier circuit for processing a signal provided by a radiation detector includes a transimpedance amplifier coupled to receive a current signal from a detector and generate a voltage signal at its output. A second amplification stage has an input coupled to an output of the transimpedance amplifier for providing an amplified voltage signal. Detector electronics include a preamplifier circuit having a first and second transimpedance amplifier coupled to receive a current signal from a first and second location on a detector, respectively, and generate a first and second voltage signal at respective outputs. A second amplification stage has an input coupled to an output of the transimpedance amplifiers for amplifying the first and said second voltage signals to provide first and second amplified voltage signals. A differential output stage is coupled to the second amplification stage for receiving the first and second amplified voltage signals and providing a pair of outputs from each of the first and second amplified voltage signals. Read out circuitry has an input coupled to receive both of the pair of outputs, the read out circuitry having structure for processing each of the pair of outputs, and providing a single digital output having a time-stamp therefrom.

  9. Inclusive Electron Scattering From Nuclei at x >1 and High Q^2

    SciTech Connect (OSTI)

    John Arrington

    1998-06-02T23:59:59.000Z

    CEBAF experiment e89-008 measured inclusive electron scattering from nuclei in a Q{sup 2} range between 0.8 and 7.3 (GeV/c){sup 2} for x{sub Bjorken} approximately greater than 1. The cross sections for scattering from D C, Fe, and Au were measured. The C, Fe, and Au data have been analyzed in terms of F(y) to examine y-scaling of the quasielastic scattering, and to study the momentum distribution of the nucleons in the nucleus. The data have also been analyzed in terms of the structure function vW{sub 2} to examine scaling of the inelastic scattering in x and xi and to study the momentum distribution of the quarks. In the regions where quasielastic scattering dominates the cross section (low Q{sup 2} or large negative values of y), the data are shown to exhibit y-scaling. However, the y-scaling breaks down once the inelastic contributions become large. The data do not exhibit x-scaling, except at the lowest values of x, while the structure function does appear to scale in the Nachtmann variable, xi.

  10. 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.

  11. VACUUM PRESSURE RISE WITH INTENSE ION BEAMS IN RHIC.

    SciTech Connect (OSTI)

    FISCHER,W.; BAI,M.; BRENNAN,J.M.; BLASKIEWICZ,M.; CAMERON,P.; HSEUH,H.C.; HUANG,H.; MACKAY,W.; ROSER,T.; SATOGATA,T.; SMART,L.A.; TRBOJEVIC,D.; ZHANG,S.Y.

    2002-06-02T23:59:59.000Z

    When RHIC is filled with bunches of intense ion beams a pressure rise is observed. The pressure rise exceeds the acceptable limit for operation with the design intensities. Observations of events leading to a pressure rise are summarized. Relevant parameters include ion species, charge per bunch, bunch spacing, and the location in the ring. Effects that contribute to a pressure rise are discussed, including beam gas ionization and ion desorption, loss-induced gas desorption, and electron desorption from electron clouds.

  12. Dynamic Fiber Optic Sensors Under Intense Radioactive Environments

    SciTech Connect (OSTI)

    Allison, S.W.; Earl, D.D.; Haines, J.R.; Tsai, C.C.

    1998-10-15T23:59:59.000Z

    A liquid mercury target will be used as the neutron source for the proposed Spallation Neutron Source facility. This target is subjected to bombardment by short-pulse, high-energy proton beams. The intense thermal loads caused by interaction of the pulsed proton beam with the mercury create an enormous rate of temperature rise ({approximately}10{sup 7} K/s) during a very brief beam pulse ({approximately } 0.5 {micro}s). The resulting pressure waves in the mercury will interact with the walls of the mercury target and may lead to large stresses. To gain confidence in the mercury target design concept and to benchmark the computer design codes, we tested various electrical and optical sensors for measuring the transient strains on the walls of a mercury container and the pressures in the mercury. The sensors were attached on several sample mercury targets that were tested at various beam facilities: Oak Ridge Electron Linear Accelerator, Los Alamos Neutron Science Center-Weapons Neutron Research, and Brookhaven National Laboratory's Alternating Gradient Synchrotron. The effects of intense background radiation on measured signals for each sensor are described and discussed. Preliminary results of limited tests at these facilities indicate that the fiber optic sensors function well in this intense radiation environment, whereas conventional electrical sensors are dysfunctional.

  13. Spectroscopy at the high-energy electron beam ion trap (Super EBIT)

    SciTech Connect (OSTI)

    Widmann, K.; Beiersdorfer, P.; Crespo Lopez-Urrutia, J.R.

    1996-07-10T23:59:59.000Z

    The following progress report presents some of the x-ray measurements performed during the last year on the Livermore SuperEBIT facility. The measurements include: direct observation of the spontaneous emission of the hyperfine transition in ground state hydrogenlike holmium, {sup 165}Ho{sup 66{plus}}; measurements of the n {equals} 2 {r_arrow} 2 transition energies in neonlike thorium, Th{sup 80{plus}}, through lithiumlike thorium, Th{sup 87{plus}}, testing the predictions of quantum electrodynamical contributions in high-Z ions up to the 0.4{percent} level; measurements of the isotope shift of the n= 2 {r_arrow} 2 transition energies between lithiumlike through carbonize uranium, {sup 233}U{sup 89{plus}...86{plus}} and {sup 238}U{sup 89{plus}...86{plus}}, inferring the variation of the mean- square nuclear charge radius; and high-resolution measurements of the K{alpha} radiation of heliumlike xenon, Xe{sup 52 {plus}}, using a transmission-type crystal spectrometer, resolving for the first time the ls2p{sup 3}P{sub 1} {r_arrow} 1S{sup 2} {sup 1}S{sub 0} and ls2s{sup 3}S{sub 1} {r_arrow} 1S{sup 2} {sup 1}S{sub 0} transitions individually. 41 refs., 9 figs., 1 tab.

  14. Evolution of magnetic and superconducting fluctuations with doping of high-T{sub c} superconductors : an electronic Raman scattering study.

    SciTech Connect (OSTI)

    Blumberg, G.

    1998-01-14T23:59:59.000Z

    For YBa{sub 2}Cu{sub 3}O{sub 6+{delta}} and Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 3{+-}{delta}} superconductors, electronic Raman scattering from high- and low-energy excitations has been studied in relation to the hole doping level, temperature, and energy of the incident photons. For underdoped superconductors, it is concluded that short range antiferromagnetic (AF) correlations persist with hole doping and doped single holes are incoherent in the AF environment. Above the superconducting (SC) transition temperature T{sub c} the system exhibits a sharp Raman resonance of B{sub 1g} symmetry and about 75 meV energy and a pseudogap for electron-hole excitations below 75 meV, a manifestation of a partially coherent state forming from doped incoherent quasi-particles. The occupancy of the coherent state increases with cooling until phase ordering at T{sub c} produces a global SC state.

  15. Energy Intensity Strategy 

    E-Print Network [OSTI]

    Rappolee, D.; Shaw, J.

    2008-01-01T23:59:59.000Z

    Our presentation will cover how we began the journey of conserving energy at our facility. We’ll discuss a basic layout of our energy intensity plan and the impact our team has had on the process, what tools we’re using, what goals have been...

  16. Intensive Observation Period Projects Scheduled

    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 PowerCherries 82981-1cnHigh SchoolIn Other NewsSpin andInterimInvokingInspector XE 20131 Intensive

  17. Compensated electron and hole pickets in an underdoped high Tc superconductor

    SciTech Connect (OSTI)

    Harrison, Neil [Los Alamos National Laboratory; Altarawneh, Moaz M [Los Alamos National Laboratory; Mielke, Charles H [Los Alamos National Laboratory; Sebastian, Suchitra E [CAMBRIDGE U; Goddard, P A [U OF OXFORD; Liang, Ruixing [U BRITISH COLUMBIA; Bonn, D A [U BRITISH COLUMBIA; Hardy, W N [U BRITISH COLUMBIA; Andersen, O K [MAX PLANCK INST.; Lonzarich, G G [CAMBRIDGE U

    2010-01-01T23:59:59.000Z

    Important to the question of high temperature superconductivity is whether bound fermionic pairs with zero or finite momentum - exhibiting bosonic physics - are involved. Here we use angle-dependent magnetic quantum oscillation measurements in underdoped YBa{sub 2}Cu{sub 3}O{sub 6+x} to reveal two significantly differently corrugated small sections of Fermi surface, identifying them as comprising opposite carriers located at different locations of the Brillouin zone. The surprising finding that these disproportionately heavy small pockets are equal in size indicates they are prone to a finite momentum excitonic insulator instability. We discuss the possibility that reducing the doping drives YBa{sub 2}Cu{sub 3}O{sub 6+x} closer to an instability of this nature, its ultimate realization occuring at the metal-insulator quantum critical point, accompanied by a potential enhancement of superconducting transition temperatures.

  18. Interfacial electron and phonon scattering processes in high-powered nanoscale applications.

    SciTech Connect (OSTI)

    Hopkins, Patrick E.

    2011-10-01T23:59:59.000Z

    The overarching goal of this Truman LDRD project was to explore mechanisms of thermal transport at interfaces of nanomaterials, specifically linking the thermal conductivity and thermal boundary conductance to the structures and geometries of interfaces and boundaries. Deposition, fabrication, and post possessing procedures of nanocomposites and devices can give rise to interatomic mixing around interfaces of materials leading to stresses and imperfections that could affect heat transfer. An understanding of the physics of energy carrier scattering processes and their response to interfacial disorder will elucidate the potentials of applying these novel materials to next-generation high powered nanodevices and energy conversion applications. An additional goal of this project was to use the knowledge gained from linking interfacial structure to thermal transport in order to develop avenues to control, or 'tune' the thermal transport in nanosystems.

  19. Anomalous Higgs-top Coupling Pollution on Triple Higgs Coupling Extraction at Future High-Luminosity Electron-Positron Collider

    E-Print Network [OSTI]

    Chen Shen; Shou-hua Zhu

    2015-04-25T23:59:59.000Z

    One of the most challenging tasks for future high-luminosity electron-positron colliders is to extract Higgs triple coupling. It was proposed that this can be carried out via the precisely measuring the cross section of ZH associated production up to $0.4\\%$. In this paper, we example the possible heavy pollution from Higgs-top anomalous coupling. Our numerical results show that the pollution is small for $\\sqrt{s}_{e^+e^-}= 240 GeV$. However for the higher energy collider, pollution is sizable, which should be taken into account. We further explored the possibility to measure CP-violated Higgs top coupling, via the forward-backward asymmetry $A_{FB}$ for the process $e^+e^- \\rightarrow ZH$. The asymmetry can reach $0.7\\%$ which is comparable to the precision of cross section measurement.

  20. Nano-structure multilayer technology fabrication of high energy density capacitors for the power electronic building book

    SciTech Connect (OSTI)

    Barbee, T.W.; Johnson, G.W.; Wagner, A.V.

    1997-10-21T23:59:59.000Z

    Commercially available capacitors do not meet the specifications of the Power Electronic Building Block (PEBB) concept. We have applied our propriety nanostructure multilayer materials technology to the fabrication of high density capacitors designed to remove this impediment to PEBB progress. Our nanostructure multilayer capacitors will also be enabling technology in many industrial and military applications. Examples include transient suppression (snubber capacitors), resonant circuits, and DC filtering in PEBB modules. Additionally, weapon applications require compact energy storage for detonators and pulsed-power systems. Commercial applications run the gamut from computers to lighting to communications. Steady progress over the last five years has brought us to the threshold of commercial manufacturability. We have demonstrated a working dielectric energy density of > 11 J/cm3 in 20 nF devices designed for 1 kV operation.