Sample records for beam particle electron

  1. 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.

  2. Resonance broadening due to particle scattering and mode-coupling in the quasi-linear relaxation of electron beams

    E-Print Network [OSTI]

    Bian, Nicolas H; Ratcliffe, Heather

    2015-01-01T23:59:59.000Z

    Of particular interest for radio and hard X-ray diagnostics of accelerated electrons during solar flares is the understanding of the basic non-linear mechanisms regulating the relaxation of electron beams propagating in turbulent plasmas. In this work, it is shown that in addition to scattering of beam electrons, scattering of the beam-generated Langmuir waves via for instance mode-coupling, can also result in broadening of the wave-particle resonance. We obtain a resonance-broadened version of weak-turbulence theory with mode-coupling to ion-sound modes. Resonance broadening is presented here as a unified framework which can quantitatively account for the reduction and possible suppression of the beam instability due to background scattering of the beam electrons themselves or due to scattering of the beam-generated Langmuir waves in fluctuating plasmas. Resonance broadening being essentially equivalent to smoothing of the electron phase-space distribution, it is used to construct an intuitive physical pictu...

  3. 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.

  4. Polarization of fast particle beams by collisional pumping

    DOE Patents [OSTI]

    Stearns, J. Warren (Castro Valley, CA); Kaplan, Selig N. (El Cerrito, CA); Pyle, Robert V. (Berkeley, CA); Anderson, L. Wilmer (Madison, WI); Ruby, Lawrence (Berkeley, CA); Schlachter, Alfred S. (Oakland, CA)

    1988-01-01T23:59:59.000Z

    Method and apparatus for highly polarizing a fast beam of particles by collisional pumping, including generating a fast beam of particles, and also generating a thick electron-spin-polarized medium positioned as a target for the beam. The target is made sufficiently thick to allow the beam to interact with the medium to produce collisional pumping whereby the beam becomes highly polarized.

  5. Polarization of fast particle beams by collisional pumping

    DOE Patents [OSTI]

    Stearns, J.W.; Kaplan, S.N.; Pyle, R.V.; Anderson, L.W.; Schlachter, A.S.; Ruby, L.

    1984-10-19T23:59:59.000Z

    The invention relates to method and apparatus for polarizing a fast beam of particles by collisional pumping, including generating a fast beam of particles, and generating a thick electron-spin-polarized medium positioned as a target for said beam, said medium being sufficiently thick to allow said beam to interact with said medium to produce collisional pumping whereby said particle beam becomes highly polarized.

  6. Beams 92: Proceedings. Volume 2, Ion beams, electron beams, diagnostics

    SciTech Connect (OSTI)

    Mosher, D.; Cooperstein, G. [eds.] [Naval Research Lab., Washington, DC (United States)] [eds.; Naval Research Lab., Washington, DC (United States)

    1993-12-31T23:59:59.000Z

    This report contains papers on the following topics. Ion beam papers; electron beam papers; and these papers have been indexed separately elsewhere.

  7. Electrostatic wire stabilizing a charged particle beam

    DOE Patents [OSTI]

    Prono, D.S.; Caporaso, G.J.; Briggs, R.J.

    1983-03-21T23:59:59.000Z

    In combination with a charged particle beam generator and accelerator, apparatus and method are provided for stabilizing a beam of electrically charged particles. A guiding means, disposed within the particle beam, has an electric charge induced upon it by the charged particle beam. Because the sign of the electric charge on the guiding means and the sign of the particle beam are opposite, the particles are attracted toward and cluster around the guiding means to thereby stabilize the particle beam as it travels.

  8. Circular, confined distribution for charged particle beams

    DOE Patents [OSTI]

    Garnett, R.W.; Dobelbower, M.C.

    1995-11-21T23:59:59.000Z

    A charged particle beam line is formed with magnetic optics that manipulate the charged particle beam to form the beam having a generally rectangular configuration to a circular beam cross-section having a uniform particle distribution at a predetermined location. First magnetic optics form a charged particle beam to a generally uniform particle distribution over a square planar area at a known first location. Second magnetic optics receive the charged particle beam with the generally square configuration and affect the charged particle beam to output the charged particle beam with a phase-space distribution effective to fold corner portions of the beam toward the core region of the beam. The beam forms a circular configuration having a generally uniform spatial particle distribution over a target area at a predetermined second location. 26 figs.

  9. Circular, confined distribution for charged particle beams

    DOE Patents [OSTI]

    Garnett, Robert W. (Los Alamos, NM); Dobelbower, M. Christian (Toledo, OH)

    1995-01-01T23:59:59.000Z

    A charged particle beam line is formed with magnetic optics that manipulate the charged particle beam to form the beam having a generally rectangular configuration to a circular beam cross-section having a uniform particle distribution at a predetermined location. First magnetic optics form a charged particle beam to a generally uniform particle distribution over a square planar area at a known first location. Second magnetic optics receive the charged particle beam with the generally square configuration and affect the charged particle beam to output the charged particle beam with a phase-space distribution effective to fold corner portions of the beam toward the core region of the beam. The beam forms a circular configuration having a generally uniform spatial particle distribution over a target area at a predetermined second location.

  10. Chemical Imaging Analysis of Environmental Particles Using the Focused Ion Beam/Scanning Electron Microscopy Technique: Microanalysis Insights into Atmospheric Chemistry of Fly Ash

    SciTech Connect (OSTI)

    Chen, Haihan; Grassian, Vicki H.; Saraf, Laxmikant V.; Laskin, Alexander

    2013-01-21T23:59:59.000Z

    Airborne fly ash from coal combustion may represent a source of bioavailable iron (Fe) in the open ocean. However, few studies have been made focusing on Fe speciation and distribution in coal fly ash. In this study, chemical imaging of fly ash has been performed using a dual-beam FIB/SEM (focused ion beam/scanning electron microscope) system for a better understanding of how simulated atmospheric processing modify the morphology, chemical compositions and element distributions of individual particles. A novel approach has been applied for cross-sectioning of fly ash specimen with a FIB in order to explore element distribution within the interior of individual particles. Our results indicate that simulated atmospheric processing causes disintegration of aluminosilicate glass, a dominant material in fly ash particles. Aluminosilicate-phase Fe in the inner core of fly ash particles is more easily mobilized compared with oxide-phase Fe present as surface aggregates on fly ash spheres. Fe release behavior depends strongly on Fe speciation in aerosol particles. The approach for preparation of cross-sectioned specimen described here opens new opportunities for particle microanalysis, particular with respect to inorganic refractive materials like fly ash and mineral dust.

  11. 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.

  12. Particle beam injector system and method

    DOE Patents [OSTI]

    Guethlein, Gary

    2013-06-18T23:59:59.000Z

    Methods and devices enable coupling of a charged particle beam to a radio frequency quadrupole accelerator. Coupling of the charged particle beam is accomplished, at least in-part, by relying on of sensitivity of the input phase space acceptance of the radio frequency quadrupole to the angle of the input charged particle beam. A first electric field across a beam deflector deflects the particle beam at an angle that is beyond the acceptance angle of the radio frequency quadrupole. By momentarily reversing or reducing the established electric field, a narrow portion of the charged particle beam is deflected at an angle within the acceptance angle of the radio frequency quadrupole. In another configuration, beam is directed at an angle within the acceptance angle of the radio frequency quadrupole by the first electric field and is deflected beyond the acceptance angle of the radio frequency quadrupole due to the second electric field.

  13. 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, ...

  14. Stability of Single Particle Motion with Head-On Beam-Beam Compensation in the RHIC

    SciTech Connect (OSTI)

    Luo,Y.; Fischer, W.; Abreu, N.

    2008-05-01T23:59:59.000Z

    To compensate the large tune shift and tune spread generated by the head-on beam-beam interactions in the polarized proton run in the Relativistic Heavy Ion Collider (RHIC), we proposed a low energy electron beam with a Gaussian transverse profiles to collide head-on with the proton beam. In this article, with a weak-strong beam-beam interaction model, we investigate the stability of single particle motion in the presence of head-on beam-beam compensation. Tune footprints, tune diffusion, Lyapunov exponents, and 10{sup 6} turn dynamic apertures are calculated and compared between the cases without and with beam-beam compensation. A tune scan is performed and the possibility of increasing the bunch intensity is studied. The cause of tune footprint foldings is discussed, and the tune diffusion and Lyapunov exponent analysis are compared.

  15. Confined energy distribution for charged particle beams

    DOE Patents [OSTI]

    Jason, Andrew J. (Los Alamos, NM); Blind, Barbara (Los Alamos, NM)

    1990-01-01T23:59:59.000Z

    A charged particle beam is formed to a relatively larger area beam which is well-contained and has a beam area which relatively uniformly deposits energy over a beam target. Linear optics receive an accelerator beam and output a first beam with a first waist defined by a relatively small size in a first dimension normal to a second dimension. Nonlinear optics, such as an octupole magnet, are located about the first waist and output a second beam having a phase-space distribution which folds the beam edges along the second dimension toward the beam core to develop a well-contained beam and a relatively uniform particle intensity across the beam core. The beam may then be expanded along the second dimension to form the uniform ribbon beam at a selected distance from the nonlinear optics. Alternately, the beam may be passed through a second set of nonlinear optics to fold the beam edges in the first dimension. The beam may then be uniformly expanded along the first and second dimensions to form a well-contained, two-dimensional beam for illuminating a two-dimensional target with a relatively uniform energy deposition.

  16. Electron beam dynamics for the ISIS bremsstrahlung beam generation system

    E-Print Network [OSTI]

    Block, Robert E. (Robert Edward)

    2011-01-01T23:59:59.000Z

    An electron beam transport system was designed for use in the Bremsstrahlung Beam Generation System of the Integrated Stand-off Inspection System (ISIS). The purpose of this electron transport system was to provide for ...

  17. Shimmed electron beam welding process

    DOE Patents [OSTI]

    Feng, Ganjiang (Clifton Park, NY); Nowak, Daniel Anthony (Alplaus, NY); Murphy, John Thomas (Niskayuna, NY)

    2002-01-01T23:59:59.000Z

    A modified electron beam welding process effects welding of joints between superalloy materials by inserting a weldable shim in the joint and heating the superalloy materials with an electron beam. The process insures a full penetration of joints with a consistent percentage of filler material and thereby improves fatigue life of the joint by three to four times as compared with the prior art. The process also allows variable shim thickness and joint fit-up gaps to provide increased flexibility for manufacturing when joining complex airfoil structures and the like.

  18. Electrostatic wire for stabilizing a charged particle beam

    DOE Patents [OSTI]

    Prono, Daniel S. (Livermore, CA); Caporaso, George J. (Livermore, CA); Briggs, Richard J. (Livermore, CA)

    1985-01-01T23:59:59.000Z

    In combination with a charged particle beam generator and accelerator, apparatus and method are provided for stabilizing a beam of electrically charged particles. A guiding means, disposed within the particle beam, has an electric charge induced upon it by the charged particle beam. Because the sign of the electric charge on the guiding means and the sign of the particle beam are opposite, the particles are attracted toward and cluster around the guiding means to thereby stabilize the particle beam as it travels.

  19. The Cooling of Particle Beams

    E-Print Network [OSTI]

    Sessler, Andrew M.

    2008-01-01T23:59:59.000Z

    67, 15. Hangst, J "Laser Cooling of a Stored Ion Beam - ATheorem an.d Phase Space Cooling", Proceedings of theWorkshop on Beam Cooling and Related Topics, Montreaux, CERN

  20. 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.

  1. Neutral particle beam sensing and steering

    DOE Patents [OSTI]

    Maier, II, William B. (Los Alamos, NM); Cobb, Donald D. (Los Alamos, NM); Robiscoe, Richard T. (Los Alamos, NM)

    1991-01-01T23:59:59.000Z

    The direction of a neutral particle beam (NPB) is determined by detecting Ly.alpha. radiation emitted during motional quenching of excited H(2S) atoms in the beam during movement of the atoms through a magnetic field. At least one detector is placed adjacent the beam exit to define an optical axis that intercepts the beam at a viewing angle to include a volume generating a selected number of photons for detection. The detection system includes a lens having an area that is small relative to the NPB area and a pixel array located in the focal plane of the lens. The lens viewing angle and area pixel array are selected to optimize the beam tilt sensitivity. In one embodiment, two detectors are placed coplanar with the beam axis to generate a difference signal that is insensitive to beam variations other than beam tilt.

  2. Particle-beam-fusion progress report, July 1979 through December 1979

    SciTech Connect (OSTI)

    Not Available

    1981-01-01T23:59:59.000Z

    The following chapters are included in this semi-annual progress report: (1) fusion target studies, (2) target experiments, (3) particle-beam source developments, (4) particle beam experiments, (5) pulsed power, (6) pulsed power applications, and (7) electron beam fusion accelerator project. (MOW)

  3. Polymer surface treatment with particle beams

    DOE Patents [OSTI]

    Stinnett, R.W.; VanDevender, J.P.

    1999-05-04T23:59:59.000Z

    A polymer surface and near surface treatment process produced by irradiation with high energy particle beams is disclosed. The process is preferably implemented with pulsed ion beams. The process alters the chemical and mechanical properties of the polymer surface in a manner useful for a wide range of commercial applications. 16 figs.

  4. A non-invasive beam profile monitor for charged particle beams

    SciTech Connect (OSTI)

    Tzoganis, Vasilis, E-mail: vasileios.tzoganis@cockcroft.ac.uk [Cockcroft Institute, Daresbury Sci-Tech, Warrington WA4 4AD (United Kingdom); Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom); RIKEN Nishina Centre, Hirosawa 2-1, Wako, Saitama 351-0198 (Japan); Welsch, Carsten P. [Cockcroft Institute, Daresbury Sci-Tech, Warrington WA4 4AD (United Kingdom); Department of Physics, University of Liverpool, Liverpool L69 7ZE (United Kingdom)

    2014-05-19T23:59:59.000Z

    Non-interceptive beam profile monitors are highly desirable in almost all particle accelerators. Such techniques are especially valuable in applications where real time monitoring of the beam properties is required while beam preservation and minimal influence on the vacuum are of the greatest importance. This applies to many kinds of accelerators such as high energy machines where the normal diagnostics cannot withstand the beam's power, medical machines where treatment time is valuable and cannot be allocated to diagnostics and also low energy, low intensity accelerators where the beam's properties are difficult to measure. This paper presents the design of a gas-jet based beam profile monitor which was developed and commissioned at the Cockcroft Institute and can operate in a very large background pressure range from 10{sup ?7} down to below 10{sup ?11} millibars. The functioning principle of the monitor is described and the first experimental results obtained using a 5?keV electron beam are discussed.

  5. Nuclear astrophysics and electron beams

    SciTech Connect (OSTI)

    Schwenk, A. [Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt (Germany)

    2013-11-07T23:59:59.000Z

    Electron beams provide important probes and constraints for nuclear astrophysics. This is especially exciting at energies within the regime of chiral effective field theory (EFT), which provides a systematic expansion for nuclear forces and electroweak operators based on quantum chromodynamics. This talk discusses some recent highlights and future directions based on chiral EFT, including nuclear structure and reactions for astrophysics, the neutron skin and constraints for the properties of neutron-rich matter in neutron stars and core-collapse supernovae, and the dark matter response of nuclei.

  6. Rippled beam free electron laser amplifier

    DOE Patents [OSTI]

    Carlsten, Bruce E. (Los Alamos, NM)

    1999-01-01T23:59:59.000Z

    A free electron laser amplifier provides a scalloping annular electron beam that interacts with the axial electric field of a TM.sub.0n mode. A waveguide defines an axial centerline and, a solenoid arranged about the waveguide produces an axial constant magnetic field within the waveguide. An electron beam source outputs a annular electron beam that interacts with the axial magnetic field to have an equilibrium radius and a ripple radius component having a variable radius with a ripple period along the axial centerline. An rf source outputs an axial electric field that propagates within the waveguide coaxial with the electron beam and has a radial mode that interacts at the electron beam at the equilibrium radius component of the electron beam.

  7. Towards demonstration of electron cooling with bunched electron beam

    SciTech Connect (OSTI)

    Fedotov, A.

    2012-01-11T23:59:59.000Z

    All electron cooling systems which were in operation so far employed electron beam generated with an electrostatic electron gun in DC operating mode, immersed in a longitudinal magnetic field. At low energies magnetic field is also being used to transport electron beam through the cooling section from the gun to the collector. At higher energies (few MeV), it was shown that one can have simpler electron beam transport without continuous magnetic field. Because of a rather weak magnetic field on the cathode and in the cooling section the latter approach was referred to as 'non-magnetized cooling', since there was no suppression of the transverse angular spread of the electron beam with the magnetic field in the cooling section. Such a cooler successfully operated at FNAL (2005-11) at electron beam energy of 4.3 MeV. Providing cooling at even higher energies would be easier with RF acceleration of electron beam, and thus using bunched electron beam for cooling. Significant efforts were devoted to explore various aspects of such bunched electron beam cooling as part of R and D of high-energy electron cooling for RHIC. However, experimental studies of such cooling are still lacking. Establishing this technique experimentally would be extremely useful for future high-energy applications. Presently there is an ongoing effort to build Proof-of-Principle (PoP) experiment of Coherent Electron Cooling (CEC) at RHIC, which promises to be superior to conventional electron cooling for high energies. Since the CEC experiment is based on bunched electron beam and it has sections where electron beam co-propagates with the ion beam at the same velocity, it also provides a unique opportunity to explore experimentally conventional electron cooling but for the first time with a bunched electron beam. As a result, it allows us to explore techniques needed for the high-energy electron cooling such as 'painting' with a short electron beam and control of ion beam distribution under cooling which is essential if cooling is provided in a collider. The software needed for comparison with the experiments is already developed as part of the previous high-energy electron cooling studies for RHIC. Since electron beam will be non-magnetized and there will be no magnetic field in the cooling section it will be also a first demonstration of fully non-magnetized cooling. The purpose of these studies was to explore whether we would be able to observe conventional electron cooling with parameters expected in the CEC PoP experiment. Below we summarize requirements on electron beam and cooling section needed for such demonstration.

  8. LONGITUDINAL RESISTIVE INSTABILITIES OF INTENSE COASTING BEAMS IN PARTICLE ACCELERATORS

    E-Print Network [OSTI]

    Neil, V. Kelvin

    2008-01-01T23:59:59.000Z

    COASTING BEAMS IN PARTICLE ACCELERATORS TWO-WEEK LOAN COpyCOASTING BEAMS IN PARTICLE ACCELERATORS v. Kelyin Neil andCOASTING BEAt\\1S nr PARTICLE ACCELERATORS* V. Kelvin Neil

  9. Particle beam generator using a radioactive source

    DOE Patents [OSTI]

    Underwood, David G. (Naperville, IL)

    1993-01-01T23:59:59.000Z

    The apparatus of the present invention selects from particles emitted by a radioactive source those particles having momentum within a desired range and focuses the selected particles in a beam having at least one narrow cross-dimension, and at the same time attenuates potentially disruptive gamma rays and low energy particles. Two major components of the present invention are an achromatic bending and focusing system, which includes sector magnets and quadrupole, and a quadrupole doublet final focus system. Permanent magnets utilized in the apparatus are constructed of a ceramic (ferrite) material which is inexpensive and easily machined.

  10. Particle beam generator using a radioactive source

    DOE Patents [OSTI]

    Underwood, D.G.

    1993-03-30T23:59:59.000Z

    The apparatus of the present invention selects from particles emitted by a radioactive source those particles having momentum within a desired range and focuses the selected particles in a beam having at least one narrow cross-dimension, and at the same time attenuates potentially disruptive gamma rays and low energy particles. Two major components of the present invention are an achromatic bending and focusing system, which includes sector magnets and quadrupole, and a quadrupole doublet final focus system. Permanent magnets utilized in the apparatus are constructed of a ceramic (ferrite) material which is inexpensive and easily machined.

  11. Carbon Fiber Damage in Particle Beam

    E-Print Network [OSTI]

    Dehning, B; Kroyer, T; Meyer, M; Sapinski, M

    2011-01-01T23:59:59.000Z

    Carbon fibers are commonly used as moving targets in beam wire scanners. The heating of the fiber due to energy loss of the particles travelling through is simulated with Geant4. The heating induced by the beam electromagnetic field is estimated with ANSYS. The heat transfer and sublimation processes are modelled. Due to the model nonlinearity, a numerical approach based on discretization of the wire movement is used to solve it for particular beams. Radiation damage to the fiber is estimated with SRIM. The model is tested with available SPS and LEP data and a dedicated damage test on the SPS beam is performed followed by a post-mortem analysis of the wire remnants. Predictions for the LHC beams are made.

  12. Focused electron and ion beam systems

    DOE Patents [OSTI]

    Leung, Ka-Ngo; Reijonen, Jani; Persaud, Arun; Ji, Qing; Jiang, Ximan

    2004-07-27T23:59:59.000Z

    An electron beam system is based on a plasma generator in a plasma ion source with an accelerator column. The electrons are extracted from a plasma cathode in a plasma ion source, e.g. a multicusp plasma ion source. The beam can be scanned in both the x and y directions, and the system can be operated with multiple beamlets. A compact focused ion or electron beam system has a plasma ion source and an all-electrostatic beam acceleration and focusing column. The ion source is a small chamber with the plasma produced by radio-frequency (RF) induction discharge. The RF antenna is wound outside the chamber and connected to an RF supply. Ions or electrons can be extracted from the source. A multi-beam system has several sources of different species and an electron beam source.

  13. Precision Absolute Beam Current Measurement of Low Power Electron Beam

    SciTech Connect (OSTI)

    Ali, M. M.; Bevins, M. E.; Degtiarenko, P.; Freyberger, A.; Krafft, G. A.

    2012-11-01T23:59:59.000Z

    Precise measurements of low power CW electron beam current for the Jefferson Lab Nuclear Physics program have been performed using a Tungsten calorimeter. This paper describes the rationale for the choice of the calorimeter technique, as well as the design and calibration of the device. The calorimeter is in use presently to provide a 1% absolute current measurement of CW electron beam with 50 to 500 nA of average beam current and 1-3 GeV beam energy. Results from these recent measurements will also be presented.

  14. Generation of anomalously energetic suprathermal electrons by an electron beam interacting with a nonuniform plasma

    E-Print Network [OSTI]

    Sydorenko, D; Chen, L; Ventzek, P L G

    2015-01-01T23:59:59.000Z

    Generation of anomalously energetic suprathermal electrons was observed in simulation of a high- voltage dc discharge with electron emission from the cathode. An electron beam produced by the emission interacts with the nonuniform plasma in the discharge via a two-stream instability. Efficient energy transfer from the beam to the plasma electrons is ensured by the plasma nonuniformity. The electron beam excites plasma waves whose wavelength and phase speed gradually decrease towards anode. The short waves near the anode accelerate plasma bulk electrons to suprathermal energies. The sheath near the anode reflects some of the accelerated electrons back into the plasma. These electrons travel through the plasma, reflect near the cathode, and enter the accelerating area again but with a higher energy than before. Such particles are accelerated to energies much higher than after the first acceleration. This mechanism plays a role in explaining earlier experimental observations of energetic suprathermal electrons i...

  15. 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.

  16. MEASUREMENT OF BEAM CHARACTERISTICS FOR PHOTO- ELECTRON BEAM...

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

    electron beam is expected to be used in a wide field, such as X-ray generation by inverse Compton scattering, pulse radiolysis, etc. The laser driven photo cathode rf gun system is...

  17. 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.

  18. Single electron beam rf feedback free electron laser

    DOE Patents [OSTI]

    Brau, C.A.; Stein, W.E.; Rockwood, S.D.

    1981-02-11T23:59:59.000Z

    A free electron laser system and electron beam system for a free electron laser which uses rf feedback to enhance efficiency are described. Rf energy is extracted from a single electron beam by decelerating cavities and energy is returned to accelerating cavities using rf returns, such as rf waveguides, rf feedthroughs, resonant feedthroughs, etc. This rf energy is added to rf klystron energy to reduce the required input energy and thereby enhance energy efficiency of the system.

  19. Big Bang Day: 5 Particles - 1. The Electron

    ScienceCinema (OSTI)

    None

    2011-04-25T23:59:59.000Z

    Simon Singh looks at the stories behind the discovery of 5 of the universe's most significant subatomic particles: the Electron, the Quark, the Anti-particle, the Neutrino and the "next particle". 1. The Electron Just over a century ago, British physicist J.J. Thompson experimenting with electric currents and charged particles inside empty glass tubes, showed that atoms are divisible into indivisible elementary particles. But how could atoms be built up of these so called "corpuscles"? An exciting 30 year race ensued, to grasp the planetary model of the atom with its orbiting electrons, and the view inside the atom was born. Whilst the number of electrons around the nucleus of an atom determines their the chemistry of all elements, the power of electrons themselves have been harnessed for everyday use: electron beams for welding,cathode ray tubes and radiation therapy.

  20. Optimal beam pattern to maximize inclusion residence time in an electron beam melting hearth

    SciTech Connect (OSTI)

    Powell, A.; Pal, U. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Avyle, J. van den [Sandia National Labs., Albuquerque, NM (United States)

    1997-02-01T23:59:59.000Z

    Approximate probabilities of inclusion survival through an electron beam melting hearth are computed from nitride dissolution rates, flotation velocities, and residence times. Dissolution rates were determined by measuring shrinkage rates of pure TiN and nitrided sponge in small pools of molten titanium in an electron beam melting hearth. Flotation velocities were calculated using correlations for fluid flow around spheres, and show that particles sink or float unless their densities are extremely close to that of molten titanium. Flow field characteristics which lead to effective inclusion removal are discussed in terms of heat flux pattern required to produce them, based on the electron beam`s unique ability to impart a nearly arbitrary heat flux pattern to the melt surface.

  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. High gradient lens for charged particle beam

    DOE Patents [OSTI]

    Chen, Yu-Jiuan

    2014-04-29T23:59:59.000Z

    Methods and devices enable shaping of a charged particle beam. A dynamically adjustable electric lens includes a series of alternating a series of alternating layers of insulators and conductors with a hollow center. The series of alternating layers when stacked together form a high gradient insulator (HGI) tube to allow propagation of the charged particle beam through the hollow center of the HGI tube. A plurality of transmission lines are connected to a plurality of sections of the HGI tube, and one or more voltage sources are provided to supply an adjustable voltage value to each transmission line of the plurality of transmission lines. By changing the voltage values supplied to each section of the HGI tube, any desired electric field can be established across the HGI tube. This way various functionalities including focusing, defocusing, acceleration, deceleration, intensity modulation and others can be effectuated on a time varying basis.

  3. Laser and Particle Beams http://journals.cambridge.org/LPB

    E-Print Network [OSTI]

    Liska, Richard

    Laser and Particle Beams http://journals.cambridge.org/LPB Additional services for Laser, J. Limpouch, R. Liska and P. Váchal Laser and Particle Beams / Volume 30 / Issue 03 / September 2012 of annularlaserbeamdriven plasma jets from massive planar targets. Laser and Particle Beams,30, pp 445457 doi:10.1017/S

  4. Jacobi equations and particle accelerator beam dynamics

    E-Print Network [OSTI]

    Ricardo Gallego Torrome

    2012-03-27T23:59:59.000Z

    A geometric formulation of the linear beam dynamics in accelerator physics is presented. In particular, it is proved that the linear transverse and longitudinal dynamics can be interpret geometrically as an approximation to the Jacobi equation of an affine averaged Lorentz connection. We introduce a specific notion reference trajectory as integral curves of the main velocity vector field. A perturbation caused by the statistical nature of the bunch of particles is considered.

  5. Non-Vacuum Electron Beam Welding

    SciTech Connect (OSTI)

    Hershcovitch, Ady

    2007-01-31T23:59:59.000Z

    Original objectives of CRADA number BNL-01-03 between BNL and Acceleron, Inc., were to further develop the Plasma Window concept (a BNL invention covered by US Patent number 5,578,831), mate the Plasma Window to an existing electron beam welder to perform in-air electron beam welding, and mount the novel nonvacuum electron beam welder on a robot arm. Except for the last objective, all other goals were met or exceeded. Plasma Window design and operation was enhanced during the project, and it was successfully mated to a conventional4 kW electron beam welder. Unprecedented high quality non-vacuum electron beam . welding was demonstrated. Additionally, a new invention the Plasma Shield (US Patent number 7,075,030) that chemically and thermally shields a target object was set forth. Great interest in the new technology was shown by a number of industries and three arcs were sold for experimental use. However, the welding industry requested demonstration of high speed welding, which requires 100 kW electron beam welders. The cost of such a welder involved the need for additional funding. Therefore, some of the effort was directed towards Plasma Shield development. Although relatively a small portion of the R&D effort was spent on the Plasma Shield, some very encouraging results were obtained. Inair Plasma Shield was demonstrated. With only a partial shield, enhanced vacuum separation and cleaner welds were realized. And, electron beam propagation in atmosphere improved by a factor of about 3. Benefits to industry are the introduction of two new technologies. BNL benefited from licensing fee cash, from partial payment for employee salary, and from a new patent In addition to financial benefits, a new technology for physics studies was developed. Recommendations for future work are to develop an under-water plasma shield, perform welding with high-power electron beam:s, carry out other plasma shielded electron beam and laser processes. Potential benefits from further R&D are that various processes involving electron ion and laser beams that have now restrictions can, with the Plasma Shield be performed in practically any environment. For example, electron beam and laser welding can be performed under water, as well as, in situ repair of ship and nuclear reactor components. The plasma shield results in both thermal (since the plasma is hotter than the environment) and chemical shielding. The latter feature brings about in-vacuum process purity out of vacuum, and the thermal shielding aspect results in higher production rates.

  6. 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.

  7. Electron beam machining using rotating and shaped beam power distribution

    DOE Patents [OSTI]

    Elmer, J.W.; O`Brien, D.W.

    1996-07-09T23:59:59.000Z

    An apparatus and method are disclosed for electron beam (EB) machining (drilling, cutting and welding) that uses conventional EB guns, power supplies, and welding machine technology without the need for fast bias pulsing technology. The invention involves a magnetic lensing (EB optics) system and electronic controls to: (1) concurrently bend, focus, shape, scan, and rotate the beam to protect the EB gun and to create a desired effective power-density distribution, and (2) rotate or scan this shaped beam in a controlled way. The shaped beam power-density distribution can be measured using a tomographic imaging system. For example, the EB apparatus of this invention has the ability to drill holes in metal having a diameter up to 1,000 {micro}m (1 mm or larger), compared to the 250 {micro}m diameter of laser drilling. 5 figs.

  8. Electron beam machining using rotating and shaped beam power distribution

    DOE Patents [OSTI]

    Elmer, John W. (Pleasanton, CA); O'Brien, Dennis W. (Livermore, CA)

    1996-01-01T23:59:59.000Z

    An apparatus and method for electron beam (EB) machining (drilling, cutting and welding) that uses conventional EB guns, power supplies, and welding machine technology without the need for fast bias pulsing technology. The invention involves a magnetic lensing (EB optics) system and electronic controls to: 1) concurrently bend, focus, shape, scan, and rotate the beam to protect the EB gun and to create a desired effective power-density distribution, and 2) rotate or scan this shaped beam in a controlled way. The shaped beam power-density distribution can be measured using a tomographic imaging system. For example, the EB apparatus of this invention has the ability to drill holes in metal having a diameter up to 1000 .mu.m (1 mm or larger), compared to the 250 .mu.m diameter of laser drilling.

  9. Scrap uranium recycling via electron beam melting

    SciTech Connect (OSTI)

    McKoon, R.

    1993-11-01T23:59:59.000Z

    A program is underway at the Lawrence Livermore National Laboratory (LLNL) to recycle scrap uranium metal. Currently, much of the material from forging and machining processes is considered radioactive waste and is disposed of by oxidation and encapsulation at significant cost. In the recycling process, uranium and uranium alloys in various forms will be processed by electron beam melting and continuously cast into ingots meeting applicable specifications for virgin material. Existing vacuum processing facilities at LLNL are in compliance with all current federal and state environmental, safety and health regulations for the electron beam melting and vaporization of uranium metal. One of these facilities has been retrofitted with an auxiliary electron beam gun system, water-cooled hearth, crucible and ingot puller to create an electron beam melt furnace. In this furnace, basic process R&D on uranium recycling will be performed with the goal of eventual transfer of this technology to a production facility.

  10. The Electron Beam Ion Source (EBIS)

    ScienceCinema (OSTI)

    Brookhaven Lab

    2010-01-08T23:59:59.000Z

    Brookhaven National Lab has successfully developed a new pre-injector system, called the Electron Beam Ion Source, for the Relativistic Heavy Ion Collider (RHIC) and NASA Space Radiation Laboratory science programs. The first of several planned improvemen

  11. Emittance growth from electron beam modulation

    SciTech Connect (OSTI)

    Blaskiewicz, M.

    2009-12-01T23:59:59.000Z

    In linac ring colliders like MeRHIC and eRHIC a modulation of the electron bunch can lead to a modulation of the beam beam tune shift and steering errors. These modulations can lead to emittance growth. This note presents simple formulas to estimate these effects which generalize some previous results.

  12. Acceleration of trapped particles and beams

    E-Print Network [OSTI]

    Er'el Granot; Boris Malomed

    2011-07-30T23:59:59.000Z

    The dynamics of a quantum particle bound by an accelerating delta-functional potential is investigated. Three cases are considered, using the reference frame moving along with the {\\delta}-function, in which the acceleration is converted into the additional linear potential. (i) A stationary regime, which corresponds to a resonance state, with a minimum degree of delocalization, supported by the accelerating potential trap. (ii) A pulling scenario: an initially bound particle follows the accelerating delta-functional trap, within a finite time. (iii) The pushing scenario: the particle, which was initially localized to the right of the repulsive delta-function, is shoved to the right by the accelerating potential. For the two latter scenarios, the life time of the trapped particle, and the largest velocity to which it can be accelerated while staying trapped, are found. Analytical approximations are developed for the cases of small and large accelerations in the pulling regime, and also for a small acceleration in the stationary situation, and in the regime of pushing. The same regimes may be realized by Airy-like planar optical beams guided by a narrow bending potential channel or crest. Physical estimates are given for an atom steered by a stylus of a scanning tunneling microscope (STM), and for the optical beam guided by a bending stripe.

  13. Electron beam cold hearth refining in Vallejo

    SciTech Connect (OSTI)

    Lowe, J.H.C. [Axel Johnson Metals, Inc., Vallejo, CA (United States)

    1994-12-31T23:59:59.000Z

    Electron Beam Cold Hearth Refining Furnace (EBCHR) in Vallejo, California is alive, well, and girding itself for developing new markets. A brief review of the twelve years experience with EBCHR in Vallejo. Acquisition of the Vallejo facility by Axel Johnson Metals, Inc. paves the way for the development of new products and markets. A discussion of some of the new opportunities for the advancement of EBCHR technology. Discussed are advantages to the EBCHR process which include: extended surface area of molten metal exposed to higher vacuum; liberation of insoluble oxide particles to the surface of the melt; higher temperatures that allowed coarse solid particles like carbides and carbonitrides to be suspended in the fluid metal as fine micro-segregates, and enhanced removal of volatile trace impurities like lead, bismuth and cadmium. Future work for the company includes the continued recycling of alloys and also fabricating stainless steel for the piping of chip assembly plants. This is to prevent `killer defects` that ruin a memory chip.

  14. Ion beam processing of advanced electronic materials

    SciTech Connect (OSTI)

    Cheung, N.W.; Marwick, A.D.; Roberto, J.B. (eds.) (California Univ., Berkeley, CA (USA); International Business Machines Corp., Yorktown Heights, NY (USA). Thomas J. Watson Research Center; Oak Ridge National Lab., TN (USA))

    1989-01-01T23:59:59.000Z

    This report contains research programs discussed at the materials research society symposia on ion beam processing of advanced electronic materials. Major topics include: shallow implantation and solid-phase epitaxy; damage effects; focused ion beams; MeV implantation; high-dose implantation; implantation in III-V materials and multilayers; and implantation in electronic materials. Individual projects are processed separately for the data bases. (CBS)

  15. Electron-beam furnace with magnetic stabilization

    SciTech Connect (OSTI)

    Harker, H.R.; Knecht, J.A. II

    1986-10-07T23:59:59.000Z

    This patent describes an electron-beam comprising: a. An evacuable chamber having a port for coupling the chamber to vacuum pump means; b. a trough-shaped hearth within the chamber for holding material to be melted, the hearth having a spout for issuing a flow of molten material therefrom; c. a crucible positioned within the chamber for receiving molten material flowing from the hearth; d. one or more electron guns each for producing an energetic beam of electrons, each electron gun being positioned a relatively large distance away from the hearth and the crucible; e. magnetic beam deflection means forming an integral part of each electron gun for scanning and shaping the beam produced thereby across the hearth or the crucible; and f. magnetic means adjacent to the hearth and the crucible for producing a relatively weak magnetic field in the vicinity of the hearth and the crucible for preventing erratic deflections of the scanning electron beams without significantly altering the trajectories of such beams.

  16. Generate Uniform Transverse Distributed Electron Beam along a Beam Line

    E-Print Network [OSTI]

    Jiao, Y

    2015-01-01T23:59:59.000Z

    It has been reported that transverse distribution shaping can help to further enhance the energy extraction efficiency in a terawatt, tapered X-ray free-electron laser. Thus, methods of creating and keeping almost uniform transverse distributed (UTD) beam within undulators are required. This study shows that a UTD electron beam can be generated within evenly distributed drift sections where undulators can be placed, by means of octupoles and particular optics. A concrete design is presented, and numerical simulations are done to verify the proposed method.

  17. 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.

  18. 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.

  19. UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC

    E-Print Network [OSTI]

    Bakeman, M.S.

    2010-01-01T23:59:59.000Z

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

  20. Automated detection and analysis of particle beams in laser-plasma accelerator simulations 367 Automated detection and analysis

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Automated detection and analysis of particle beams in laser-plasma accelerator simulations 367 0 Automated detection and analysis of particle beams in laser-plasma accelerator simulations Daniela M (particle) accelerators [Geddes et al. (2009); Tajima & Dawson (1979)] model the acceleration of electrons

  1. Free Electron Lasers using `Beam by Design'

    E-Print Network [OSTI]

    Henderson, J R; McNeil, B W J

    2015-01-01T23:59:59.000Z

    Several methods have been proposed in the literature to improve Free Electron Laser output by transforming the electron phase-space before entering the FEL interaction region. By utilising `beam by design' with novel undulators and other beam changing elements, the operating capability of FELs may be further usefully extended. This paper introduces two new such methods to improve output from electron pulses with large energy spreads and the results of simulations of these methods in the 1D limit are presented. Both methods predict orders of magnitude improvements to output radiation powers.

  2. Ultrafast Time-Resolved Electron Diffraction with Megavolt Electron Beams

    SciTech Connect (OSTI)

    Hastings, J.B.; /SLAC; Rudakov, F.M.; /Brown U.; Dowell, D.H.; Schmerge, J.F.; /SLAC; Cardoza, J.D.; /Brown U.; Castro, J.M.; Gierman, S.M.; Loos, H.; /SLAC; Weber, P.M.; /Brown U.

    2006-10-24T23:59:59.000Z

    An rf photocathode electron gun is used as an electron source for ultrafast time-resolved pump-probe electron diffraction. We observed single-shot diffraction patterns from a 160 nm Al foil using the 5.4 MeV electron beam from the Gun Test Facility at the Stanford Linear Accelerator. Excellent agreement with simulations suggests that single-shot diffraction experiments with a time resolution approaching 100 fs are possible.

  3. SPALLATION NEUTRON SOURCE BEAM CURRENT MONITOR ELECTRONICS.

    SciTech Connect (OSTI)

    KESSELMAN, M.

    2001-06-18T23:59:59.000Z

    The Spallation Neutron Source (SNS) to be constructed at ORNL is a collaboration of six laboratories. Beam current monitors for SNS will be used to monitor H-minus and H-plus beams ranging from the 15 mA (tune-up in the Front End and Linac) to over 60 A fully accumulated in the Ring. The time structure of the beams to be measured range from 645 nsec ''mini'' bunches, at the 1.05 MHz ring revolution rate, to an overall 1 mS long macro pulse. Beam current monitors (BCMs) for SNS have requirements depending upon their location within the system. The development of a general approach to satisfy requirements of various locations with common components is a major design objective. This paper will describe the development of the beam current monitors and electronics.

  4. 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.

  5. 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.

  6. BOA, Beam Optics Analyzer A Particle-In-Cell Code

    SciTech Connect (OSTI)

    Thuc Bui

    2007-12-06T23:59:59.000Z

    The program was tasked with implementing time dependent analysis of charges particles into an existing finite element code with adaptive meshing, called Beam Optics Analyzer (BOA). BOA was initially funded by a DOE Phase II program to use the finite element method with adaptive meshing to track particles in unstructured meshes. It uses modern programming techniques, state-of-the-art data structures, so that new methods, features and capabilities are easily added and maintained. This Phase II program was funded to implement plasma simulations in BOA and extend its capabilities to model thermal electrons, secondary emissions, self magnetic field and implement a more comprehensive post-processing and feature-rich GUI. The program was successful in implementing thermal electrons, secondary emissions, and self magnetic field calculations. The BOA GUI was also upgraded significantly, and CCR is receiving interest from the microwave tube and semiconductor equipment industry for the code. Implementation of PIC analysis was partially successful. Computational resource requirements for modeling more than 2000 particles begin to exceed the capability of most readily available computers. Modern plasma analysis typically requires modeling of approximately 2 million particles or more. The problem is that tracking many particles in an unstructured mesh that is adapting becomes inefficient. In particular memory requirements become excessive. This probably makes particle tracking in unstructured meshes currently unfeasible with commonly available computer resources. Consequently, Calabazas Creek Research, Inc. is exploring hybrid codes where the electromagnetic fields are solved on the unstructured, adaptive mesh while particles are tracked on a fixed mesh. Efficient interpolation routines should be able to transfer information between nodes of the two meshes. If successfully developed, this could provide high accuracy and reasonable computational efficiency.

  7. 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.

  8. Electron Beam Polarization Measurement Using Touschek Lifetime Technique

    SciTech Connect (OSTI)

    Sun, Changchun; /Duke U., DFELL; Li, Jingyi; /Duke U., DFELL; Mikhailov, Stepan; /Duke U., DFELL; Popov, Victor; /Duke U., DFELL; Wu, Wenzhong; /Duke U., DFELL; Wu, Ying; /Duke U., DFELL; Chao, Alex; /SLAC; Xu, Hong-liang; /Hefei, NSRL; Zhang, Jian-feng; /Hefei, NSRL

    2012-08-24T23:59:59.000Z

    Electron beam loss due to intra-beam scattering, the Touschek effect, in a storage ring depends on the electron beam polarization. The polarization of an electron beam can be determined from the difference in the Touschek lifetime compared with an unpolarized beam. In this paper, we report on a systematic experimental procedure recently developed at Duke FEL laboratory to study the radiative polarization of a stored electron beam. Using this technique, we have successfully observed the radiative polarization build-up of an electron beam in the Duke storage ring, and determined the equilibrium degree of polarization and the time constant of the polarization build-up process.

  9. Electron gun jitter effects on beam bunching

    SciTech Connect (OSTI)

    Liu, M. S. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Iqbal, M., E-mail: muniqbal.chep@pu.edu.pk [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan)

    2014-02-15T23:59:59.000Z

    For routine operation of Beijing Electron Positron Collider II (BEPCII) linac, many factors may affect the beam bunching process directly or indirectly. We present the measurements and analyses of the gun timing jitter, gun high voltage jitter, and beam energy at the exit of the standard acceleration section of the linac quantitatively. Almost 80 mV and more than 200 ps of gun high voltage and time jitters have ever been measured, respectively. It was analyzed that the gun timing jitter produced severe effects on beam energy than the gun high voltage jitter, if the timing jitter exceeded 100 ps which eventually deteriorates both the beam performance and the injection rate to the storage ring.

  10. Polarized electron beams at milliampere average current

    SciTech Connect (OSTI)

    Poelker, Matthew [JLAB

    2013-11-01T23:59:59.000Z

    This contribution describes some of the challenges associated with developing a polarized electron source capable of uninterrupted days-long operation at milliAmpere average beam current with polarization greater than 80%. Challenges will be presented in the context of assessing the required level of extrapolation beyond the performance of today's CEBAF polarized source operating at ~ 200 uA average current. Estimates of performance at higher current will be based on hours-long demonstrations at 1 and 4 mA. Particular attention will be paid to beam-related lifetime-limiting mechanisms, and strategies to construct a photogun that operate reliably at bias voltage > 350kV.

  11. Compact two-beam push-pull free electron laser

    DOE Patents [OSTI]

    Hutton, Andrew (Yorktown, VA)

    2009-03-03T23:59:59.000Z

    An ultra-compact free electron laser comprising a pair of opposed superconducting cavities that produce identical electron beams moving in opposite directions such that each set of superconducting cavities accelerates one electron beam and decelerates the other electron beam. Such an arrangement, allows the energy used to accelerate one beam to be recovered and used again to accelerate the second beam, thus, each electron beam is decelerated by a different structure than that which accelerated it so that energy exchange rather than recovery is achieved resulting in a more compact and highly efficient apparatus.

  12. Temperature dependence of electron-beam induced effects in amorphous...

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

    and the electron hammering effect, respectively. Citation: Bae IT, Y Zhang, WJ Weber, M Ishimaru, Y Hirotsu, and M Higuchi.2008."Temperature dependence of electron-beam...

  13. SPALLATION NEUTRON SOURCE BEAM CURRENT MONITOR ELECTRONICS.

    SciTech Connect (OSTI)

    KESSELMAN,M.; DAWSON,W.C.

    2002-05-06T23:59:59.000Z

    This paper will discuss the present electronics design for the beam current monitor system to be used throughout the Spallation Neutron Source (SNS) under construction at Oak Ridge National Laboratory. The beam is composed of a micro-pulse structure due to the 402.5MHz RF, and is chopped into mini-pulses of 645ns duration with a 300ns gap, providing a macro-pulse of 1060 mini-pulses repeating at a 60Hz rate. Ring beam current will vary from about 15ma peak during studies, to about 50Amps peak (design to 100 amps). A digital approach to droop compensation has been implemented and initial test results presented.

  14. Autogenerator of beams of charged particles

    DOE Patents [OSTI]

    Adler, R.J.; Mazarakis, M.G.; Miller, R.M.; Shope, S.L.; Smith, D.L.

    1983-10-31T23:59:59.000Z

    An autogenerating apparatus provides secondary intense relativistic current beam pulses in response to an injected beam pulse. One or more electromagnetic energy storage devices are provided in conjunction with gaps along a beam propagation path for the injected beam pulse. For injected beam pulses which are no longer than double the transit time of electromagnetic waves within the storage devices (which may be resonant cavities), distinct secondary beam pulses are generated by each of the energy storage devices. The beam propagation path, together with the one or more gaps provided therein, operates as a pulse forming transmission line cavity, in which the separate cavities associated with the gaps provide delays for electromagnetic waves generated at the gaps. After doubly traversing the cavity, the electromagnetic waves cause the gap to generate the secondary beam pulses, which are thus delayed by a time interval equal to the double transit time for the induced wave within the cavity.

  15. Autogenerator of beams of charged particles

    DOE Patents [OSTI]

    Adler, Richard J. (Albuquerque, NM); Mazarakis, Michael G. (Albuquerque, NM); Miller, Robert B. (Albuquerque, NM); Shope, Steven L. (Albuquerque, NM); Smith, David L. (Albuquerque, NM)

    1986-01-01T23:59:59.000Z

    An autogenerating apparatus provides secondary intense relativistic current beam pulses in response to an injected beam pulse. One or more electromagnetic energy storage devices are provided in conjunction with gaps along a beam propagation path for the injected beam pulse. For injected beam pulses which are no longer than double the transit time of electromagnetic waves within the storage devices (which may be resonant cavities), distinct secondary beam pulses are generated by each of the energy storage devices. The beam propagation path, together with the one or more gaps provided therein, operates as a pulse forming transmission line cavity, in which the separate cavities associated with the gaps provide delays for electromagnetic waves generated at the gaps. After doubly traversing the cavity, the electromagnetic waves cause the gap to generate the secondary beam pulses, which are thus delayed by a time interval equal to the double transit time for the induced wave within the cavity.

  16. Viewing device for electron-beam equipment

    SciTech Connect (OSTI)

    Nasyrov, R.S.

    1985-06-01T23:59:59.000Z

    Viewing devices are used to observe melting, welding, and so on in vacuum systems, an it is necessary to protect the windows from droplets and vapor. A viewing device for electron-beam equipment is described in which the viewing tube and mounting flange are made as a tubular ball joint enclosed in a steel bellows, which render the viewing device flexible. Bending the viewing tube in the intervals between observations protects the viewing window from sputtering and from drops of molten metal.

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

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

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

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

    E-Print Network [OSTI]

    Knowles, David William

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

  19. Bunch length effects in the beam-beam compensation with an electron lens

    SciTech Connect (OSTI)

    Fischer, W.; Luo, Y.; Montag, C.

    2010-02-25T23:59:59.000Z

    Electron lenses for the head-on beam-beam compensation are under construction at the Relativistic Heavy Ion Collider. The bunch length is of the same order as the {beta}-function at the interaction point, and a proton passing through another proton bunch experiences a substantial phase shift which modifies the beam-beam interaction. We review the effect of the bunch length in the single pass beam-beam interaction, apply the same analysis to a proton passing through a long electron lens, and study the single pass beam-beam compensation with long bunches. We also discuss the beam-beam compensation of the electron beam in an electron-ion collider ring.

  20. Electron beam directed energy device and methods of using same

    DOE Patents [OSTI]

    Retsky, Michael W. (Trumbull, CT)

    2007-10-16T23:59:59.000Z

    A method and apparatus is disclosed for an electron beam directed energy device. The device consists of an electron gun with one or more electron beams. The device includes one or more accelerating plates with holes aligned for beam passage. The plates may be flat or preferably shaped to direct each electron beam to exit the electron gun at a predetermined orientation. In one preferred application, the device is located in outer space with individual beams that are directed to focus at a distant target to be used to impact and destroy missiles. The aimings of the separate beams are designed to overcome Coulomb repulsion. A method is also presented for directing the beams to a target considering the variable terrestrial magnetic field. In another preferred application, the electron beam is directed into the ground to produce a subsurface x-ray source to locate and/or destroy buried or otherwise hidden objects including explosive devices.

  1. Beam conditioner for free electron lasers and synchrotrons

    DOE Patents [OSTI]

    Liu, H.; Neil, G.R.

    1998-09-08T23:59:59.000Z

    A focused optical has been used to introduce an optical pulse, or electromagnetic wave, collinear with the electron beam in a free electron laser or synchrotron thereby adding an axial field component that accelerates the electrons on the radial outside of the distribution of electrons in the electron beam. This invention consists of using the axial electrical component of a TEM{sub 10} mode Gaussian beam in vacuum to condition the electron beam and speed up the outer electrons in the beam. The conditioning beam should possess about the same diameter as the electron beam. The beam waist of the conditioning wave must be located around the entrance of the undulator longitudinally to have a net energy exchange between the electrons in the outer part of the distribution and the conditioning wave owing to the natural divergence of a Gaussian beam. By accelerating the outer electrons, the outer and core electrons are caused to stay in phase. This increases the fraction of the electron beam energy that is converted to light thereby improving the efficiency of conversion of energy to light and therefore boosting the power output of the free electron laser and synchrotron. 4 figs.

  2. Beam conditioner for free electron lasers and synchrotrons

    DOE Patents [OSTI]

    Liu, Hongxiu (Williamsburg, VA); Neil, George R. (Williamsburg, VA)

    1998-01-01T23:59:59.000Z

    A focused optical is been used to introduce an optical pulse, or electromagnetic wave, colinearly with the electron beam in a free electron laser or synchrotron thereby adding an axial field component that accelerates the electrons on the radial outside of the distribution of electrons in the electron beam. This invention consists of using the axial electrical component of a TEM.sub.10 mode Gaussian beam in vacuum to condition the electron beam and speed up the outer electrons in the beam. The conditioning beam should possess about the same diameter as the electron beam. The beam waist of the conditioning wave must be located around the entrance of the undulator longitudinally to have a net energy exchange between the electrons in the outer part of the distribution and the conditioning wave owing to the natural divergence of a Gaussian beam. By accelerating the outer electrons, the outer and core electrons are caused to stay in phase. This increases the fraction of the electron beam energy that is converted to light thereby improving the efficiency of conversion of energy to light and therefore boosting the power output of the free electron laser and synchrotron.

  3. Particle beam fusion progress report for 1989

    SciTech Connect (OSTI)

    Sweeney, M.A. [ed.] [Sandia National Labs., Albuquerque, NM (United States). Pulsed Power Sciences Center

    1994-08-01T23:59:59.000Z

    This report summarizes the progress on the pulsed power approach to inertial confinement fusion. In 1989, the authors achieved a proton focal intensity of 5 TW/cm{sup 2} on PBFA-II in a 15-cm-radius applied magnetic-field (applied-B) ion diode. This is an improvement by a factor of 4 compared to previous PBFA-II experiments. They completed development of the three-dimensional (3-D), electromagnetic, particle-in-cell code QUICKSILVER and obtained the first 3-D simulations of an applied-B ion diode. The simulations, together with analytic theory, suggest that control of electromagnetic instabilities could reduce ion divergence. In experiments using a lithium fluoride source, they delivered 26 kJ of lithium energy to the diode axis. Rutherford-scattered ion diagnostics have been developed and tested using a conical foil located inside the diode. They can now obtain energy density profiles by using range filters and recording ion images on nuclear track recording film. Timing uncertainties in power flow experiments on PBFA-II have been reduced by a factor of 5. They are investigating three plasma opening switches that use magnetic fields to control and confine the injected plasma. These new switches provide better power flow than the standard plasma erosion switch. Advanced pulsed-power fusion drivers will require extraction-geometry applied-B ion diodes. During this reporting period, progress was made in evaluating the generation, transport, and focus of multiple ion beams in an extraction geometry and in assessing the probable damage to a target chamber first wall.

  4. Cyclotron-undulator cooling of a free-electron-laser beam

    SciTech Connect (OSTI)

    Bandurkin, I. V.; Kuzikov, S. V. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Savilov, A. V. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod (Russian Federation); Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod (Russian Federation)

    2014-08-18T23:59:59.000Z

    We propose methods of fast cooling of an electron beam, which are based on wiggling of particles in an undulator in the presence of an axial magnetic field. We use a strong dependence of the axial electron velocity on the oscillatory velocity, when the electron cyclotron frequency is close to the frequency of electron wiggling in the undulator field. The abnormal character of this dependence (when the oscillatory velocity increases with the increase of the input axial velocity) can be a basis of various methods for fast cooling of moderately relativistic (several MeV) electron beams.

  5. Polarized electron beams at milliampere average current

    SciTech Connect (OSTI)

    Poelker, M. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States)

    2013-11-07T23:59:59.000Z

    This contribution describes some of the challenges associated with developing a polarized electron source capable of uninterrupted days-long operation at milliAmpere average beam current with polarization greater than 80%. Challenges will be presented in the context of assessing the required level of extrapolation beyond the performance of today’s CEBAF polarized source operating at ? 200 uA average current. Estimates of performance at higher current will be based on hours-long demonstrations at 1 and 4 mA. Particular attention will be paid to beam-related lifetime-limiting mechanisms, and strategies to construct a photogun that operate reliably at bias voltage > 350kV.

  6. 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.

  7. Resurrection of beam conditioning for free electron lasers

    E-Print Network [OSTI]

    Xie, Ming

    2003-01-01T23:59:59.000Z

    t z , Undulators and Free-Electron Lasers, (Clarendon Press,a fatal flaw in a Free Electron Laser ( F E L ) beamO N Operation of free electron lasers in shorter wavelength

  8. Advanced methods for the computation of particle beam transport and the computation of electromagnetic fields and beam-cavity interactions

    SciTech Connect (OSTI)

    Dragt, A.J.; Gluckstern, R.L.

    1990-11-01T23:59:59.000Z

    The University of Maryland Dynamical Systems and Accelerator Theory Group carries out research in two broad areas: the computation of charged particle beam transport using Lie algebraic methods and advanced methods for the computation of electromagnetic fields and beam-cavity interactions. Important improvements in the state of the art are believed to be possible in both of these areas. In addition, applications of these methods are made to problems of current interest in accelerator physics including the theoretical performance of present and proposed high energy machines. The Lie algebraic method of computing and analyzing beam transport handles both linear and nonlinear beam elements. Tests show this method to be superior to the earlier matrix or numerical integration methods. It has wide application to many areas including accelerator physics, intense particle beams, ion microprobes, high resolution electron microscopy, and light optics. With regard to the area of electromagnetic fields and beam cavity interactions, work is carried out on the theory of beam breakup in single pulses. Work is also done on the analysis of the high behavior of longitudinal and transverse coupling impendances, including the examination of methods which may be used to measure these impedances. Finally, work is performed on the electromagnetic analysis of coupled cavities and on the coupling of cavities to waveguides.

  9. Josephson Junctions and Devices fabricated by Focused Electron Beam Irradiation

    E-Print Network [OSTI]

    Booij, Wilfred Edwin

    Josephson Junctions and Devices fabricated by Focused Electron Beam Irradiation Wilfred Edwin Booij Gonville and Caius College Cambridge A dissertation submitted for the degree of Doctor of Philosophy at the University of Cambridge December 1997... Summary Josephson Junctions and Devices fabricated by Focused Electron Beam Irradiation The irradiation of high Tc superconducting thin films with a focused electron beam, such as that obtained in a scanning transmission electron microscope (STEM), can...

  10. 100 years of elementary particles [Beam Line, vol. 27, issue 1, Spring 1997

    SciTech Connect (OSTI)

    Pais, Abraham; Weinberg, Steven; Quigg, Chris; Riordan, Michael; Panofsky, Wolfgang K.H.; Trimble, Virginia

    1997-04-01T23:59:59.000Z

    This issue of Beam Line commemorates the 100th anniversary of the April 30, 1897 report of the discovery of the electron by J.J. Thomson and the ensuing discovery of other subatomic particles. In the first three articles, theorists Abraham Pais, Steven Weinberg, and Chris Quigg provide their perspectives on the discoveries of elementary particles as well as the implications and future directions resulting from these discoveries. In the following three articles, Michael Riordan, Wolfgang Panofsky, and Virginia Trimble apply our knowledge about elementary particles to high-energy research, electronics technology, and understanding the origin and evolution of our Universe.

  11. PURIFICATION OF IRIDIUM BY ELECTRON BEAM MELTING

    SciTech Connect (OSTI)

    Ohriner, Evan Keith [ORNL

    2008-01-01T23:59:59.000Z

    The purification of iridium metal by electron beam melting has been characterized for 48 impurity elements. Chemical analysis was performed by glow discharge mass spectrographic (GDMS) analysis for all elements except carbon, which was analyzed by combustion. The average levels of individual elemental impurities in the starting powder varied from 37 g/g to 0.02 g/g. The impurity elements Li, Na, Mg, P, S, Cl, K, Ca, Mn, Co, Ni, Cu, Zn, As, Pd, Ag, Cd, Sn, Sb, Te, Ba, Ce, Tl, Pb, and Bi were not detectable following the purification. No significant change in concentration of the elements Ti, V, Zr, Nb, Mo, and Re was found. The elements B, C, Al, Si, Cr, Fe, Ru, Rh, and Pt were partially removed by vaporization during electron beam melting. Langmuir's equation for ideal vaporization into a vacuum was used to calculate for each impurity element the expected ratio of impurity content after melting to that before melting. Equilibrium vapor pressures were calculated using Henry's law, with activity coefficients obtained from published data for the elements Fe, Ti, and Pt. Activity coefficients were estimated from enthalpy data for Al, Si, V, Cr, Mn, Co, Ni, Zr, Nb, Mo, and Hf and an ideal solution model was used for the remaining elements. The melt temperature was determined from measured iridium weight loss. Excellent agreement was found between measured and calculated impurity ratios for all impurity elements. The results are consistent with some localized heating of the melt pool due to rastering of the electron beam, with an average vaporization temperature of 3100 K as compared to a temperature of 2965 K calculated for uniform heating of the melt pool. The results are also consistent with ideal mixing in the melt pool.

  12. Decarburization of uranium via electron beam processing

    SciTech Connect (OSTI)

    McKoon, R H

    1998-10-23T23:59:59.000Z

    For many commercial and military applications, the successive Vacuum Induction Melting of uranium metal in graphite crucibles results in a product which is out of specification in carbon. The current recovery method involves dissolution of the metal in acid and chemical purification. This is both expensive and generates mixed waste. A study was undertaken at Lawrence Livermore National Laboratory to investigate the feasibility of reducing the carbon content of uranium metal using electron beam techniques. Results will be presented on the rate and extent of carbon removal as a function of various operating parameters.

  13. Two-Beam Instability in Electron Cooling

    SciTech Connect (OSTI)

    Burov, Alexey V.; /Fermilab

    2006-04-01T23:59:59.000Z

    The drift motion of cooling electrons makes them able to respond to transverse perturbations of a cooled ion beam. This response may lead to dipole or quadrupole transverse instabilities at specific longitudinal wave numbers. While the dipole instabilities can be suppressed by a combination of the Landau damping, machine impedance, and the active damper, the quadrupole and higher order modes can lead to either emittance growth, or a lifetime degradation, or both. The growth rates of these instabilities are strongly determined by the machine x-y coupling. Thus, tuning out of the coupling resonance and/or reduction of the machine coupling can be an efficient remedy for these instabilities.

  14. accelerated electron beams: Topics by E-print Network

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

    of the various flavors of Particle Accelerator Conferences 23 contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series 24 contains one...

  15. accelerator electron beam: Topics by E-print Network

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

    of the various flavors of Particle Accelerator Conferences 23 contain a large number of EC-related publications. The ICFA Beam Dynamics Newsletter series 24 contains one...

  16. Extraction of a steady state electron beam from HCD (hollow cathode discharge) plasmas for EBIS (electron beam ion source) applications

    SciTech Connect (OSTI)

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

    1988-01-01T23:59:59.000Z

    Experiments to extract high brightness electron beams from hollow cathode discharge plasmas are now in progress. A unique feature of these plasmas, which in principle can facilitate the extraction of large current low emittance electron beams, is the existence of a relatively high energy electron population with a very narrow energy spread. This electron population was identified in a self-extraction experiment, which yielded a 35 eV, 600 mA electron beam with parallel energy spread of less than 0.5 eV. Preliminary, crude application of 2.5 kV extraction voltage yielded a steady state electron beam current of 1.2 A. The end result of this endeavor would be an Electron Beam Ion Source (EBIS) with an electron beam current of 6 A. 4 refs., 2 figs.

  17. Systems and methods of varying charged particle beam spot size

    DOE Patents [OSTI]

    Chen, Yu-Jiuan

    2014-09-02T23:59:59.000Z

    Methods and devices enable shaping of a charged particle beam. A modified dielectric wall accelerator includes a high gradient lens section and a main section. The high gradient lens section can be dynamically adjusted to establish the desired electric fields to minimize undesirable transverse defocusing fields at the entrance to the dielectric wall accelerator. Once a baseline setting with desirable output beam characteristic is established, the output beam can be dynamically modified to vary the output beam characteristics. The output beam can be modified by slightly adjusting the electric fields established across different sections of the modified dielectric wall accelerator. Additional control over the shape of the output beam can be excreted by introducing intentional timing de-synchronization offsets and producing an injected beam that is not fully matched to the entrance of the modified dielectric accelerator.

  18. Electron beam diagnostic for space charge measurement of an ion beam

    SciTech Connect (OSTI)

    Roy, Prabir K.; Yu, Simon S.; Henestroza, Enrique; Eylon, Shmuel; Shuman, Derek B.; Ludvig, Jozsef; Bieniosek, Frank M.; Waldron, William L.; Greenway, Wayne G.; Vanecek, David L.; Hannink, Ryan; Amezcua, Monserrat

    2004-09-25T23:59:59.000Z

    A non-perturbing electron beam diagnostic system for measuring the charge distribution of an ion beam is developed for Heavy Ion Fusion (HIF) beam physics studies. Conventional diagnostics require temporary insertion of sensors into the beam, but such diagnostics stop the beam, or significantly alter its properties. In this diagnostic a low energy, low current electron beam is swept transversely across the ion beam; the measured electron beam deflection is used to infer the charge density profile of the ion beam. The initial application of this diagnostic is to the Neutralized Transport Experiment (NTX), which is exploring the physics of space-charge-dominated beam focusing onto a small spot using a neutralizing plasma. Design and development of this diagnostic and performance with the NTX ion beamline is presented.

  19. 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...

  20. Particle beam and crabbing and deflecting structure

    DOE Patents [OSTI]

    Delayen, Jean (Yorktown, VA)

    2011-02-08T23:59:59.000Z

    A new type of structure for the deflection and crabbing of particle bunches in particle accelerators comprising a number of parallel transverse electromagnetic (TEM)-resonant) lines operating in opposite phase from each other. Such a structure is significantly more compact than conventional crabbing cavities operating the transverse magnetic TM mode, thus allowing low frequency designs.

  1. Electron beam diagnostic system using computed tomography and an annular sensor

    DOE Patents [OSTI]

    Elmer, John W.; Teruya, Alan T.

    2014-07-29T23:59:59.000Z

    A system for analyzing an electron beam including a circular electron beam diagnostic sensor adapted to receive the electron beam, the circular electron beam diagnostic sensor having a central axis; an annular sensor structure operatively connected to the circular electron beam diagnostic sensor, wherein the sensor structure receives the electron beam; a system for sweeping the electron beam radially outward from the central axis of the circular electron beam diagnostic sensor to the annular sensor structure wherein the electron beam is intercepted by the annular sensor structure; and a device for measuring the electron beam that is intercepted by the annular sensor structure.

  2. Heavy Oil Upgrading from Electron Beam (E-Beam) Irradiation 

    E-Print Network [OSTI]

    Yang, Daegil

    2011-02-22T23:59:59.000Z

    hydrocarbons. Second, we studied the energy transfer mechanism of E-Beam upgrading to optimize the process. Third, we conducted a preliminary economic analysis based on energy consumption and compared the economics of E-Beam upgrading with conventional...

  3. Computationally efficient description of relativistic electron beam transport in collisionless plasma

    E-Print Network [OSTI]

    Kaganovich, Igor

    Computationally efficient description of relativistic electron beam transport in collisionless and relativistic electron beam transport in collisionless background plasma is developed. Beam electrons of the Weibel instability are derived for the cold and finite-temperature beams. © 2007 American Institute

  4. Particle acceleration in electron-ion jets

    E-Print Network [OSTI]

    K. -I. Nishikawa; P. Hardee; C. B. Hededal; G. Richardson; R. Preece; H. Sol; G. J. Fishman; C. Kouvelioutou; Y. Mizuno

    2005-09-20T23:59:59.000Z

    Weibel instability created in collisionless shocks is responsible for particle (electron, positron, and ion) acceleration. Using a 3-D relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic electron-ion jet fronts propagating into an ambient plasma without initial magnetic fields with a longer simulation system in order to investigate nonlinear stage of the Weibel instability and its acceleration mechanism. The current channels generated by the Weibel instability induce the radial electric fields. The z component of the Poynting vector (E x B) become positive in the large region along the jet propagation direction. This leads to the acceleration of jet electrons along the jet. In particular the E x B drift with the large scale current channel generated by the ion Weibel instability accelerate electrons effectively in both parallel and perpendicular directions.

  5. Electron beam melting state-of-the-art 1984

    SciTech Connect (OSTI)

    Bakish, R.

    1984-06-01T23:59:59.000Z

    In 1984 electron beam melting and refining appear poised for an important new growth phase. The driving force for this phase is improved production economics made possible by technological advances. There is also a new and exciting growth application for electron beam melting: its use for surface properties beneficiation. This article is based in part on the content of the Conference on Electron Beam Melting and Refining, The State-of-the-Art 1983, held in November 1983 in Reno, Nevada.

  6. Study on electron beam in a low energy plasma focus

    SciTech Connect (OSTI)

    Khan, Muhammad Zubair, E-mail: mzubairkhan-um76@yahoo.com [Plasma Technology Research Center, Department of Physics, Faculty of Science, University Malaya, 50603 Kuala Lumpur, Malaysia and Department of Physics, Federal Urdu University of Arts, Science and Technology, 45320 Islamabad (Pakistan); Ling, Yap Seong; San, Wong Chiow [Plasma Technology Research Center, Department of Physics, Faculty of Science, University Malaya, 50603 Kuala Lumpur (Malaysia)

    2014-03-05T23:59:59.000Z

    Electron beam emission was investigated in a low energy plasma focus device (2.2 kJ) using copper hollow anode. Faraday cup was used to estimate the energy of the electron beam. XR100CR X-ray spectrometer was used to explore the impact of the electron beam on the target observed from top-on and side-on position. Experiments were carried out at optimized pressure of argon gas. The impact of electron beam is exceptionally notable with two different approaches using lead target inside hollow anode in our plasma focus device.

  7. Betatron radiation from electron beams in plasma focusing channels

    E-Print Network [OSTI]

    Esarey, E.; Catravas, P.; Leemans, W.P.

    2000-01-01T23:59:59.000Z

    Betatron Radiation from Electron Beams in Plasma FocusingAbstract. Spontaneous radiation emitted from an electronfrequency of spontaneous radiation is a strong function of

  8. Electron-beam induced recrystallization in amorphous apatite...

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

    recrystallization observed in the present study. Citation: Bae IT, Y Zhang, WJ Weber, M Higuchi, and L Giannuzzi.2007."Electron-beam induced recrystallization in amorphous...

  9. Endoscopic Electron-Beam Cancer Therapy | Argonne National Laboratory

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

    Endoscopic Electron-Beam Cancer Therapy Technology available for licensing: A successful and cost-effective means of treating cancer in previously inoperable or radiation-sensitive...

  10. Longitudinal bunch profile and electron beam energy spread

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

    APS Storage Ring Parameters Previous: Storage Ring Operation Modes Longitudinal bunch profile and electron beam energy spread Longitudinal bunch profile depends mainly on the...

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

    DOE Patents [OSTI]

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

    1984-03-22T23:59:59.000Z

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

  12. 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.

  13. Nonlinear transmission line based electron beam driver

    SciTech Connect (OSTI)

    French, David M.; Hoff, Brad W.; Tang Wilkin; Heidger, Susan; Shiffler, Don [Directed Energy Directorate, Air Force Research Laboratory, Kirtland AFB, New Mexico 87117 (United States); Allen-Flowers, Jordan [Program in Applied Mathematics, University of Arizona, Tucson, Arizona 85721 (United States)

    2012-12-15T23:59:59.000Z

    Gated field emission cathodes can provide short electron pulses without the requirement of laser systems or cathode heating required by photoemission or thermionic cathodes. The large electric field requirement for field emission to take place can be achieved by using a high aspect ratio cathode with a large field enhancement factor which reduces the voltage requirement for emission. In this paper, a cathode gate driver based on the output pulse train from a nonlinear transmission line is experimentally demonstrated. The application of the pulse train to a tufted carbon fiber field emission cathode generates short electron pulses. The pulses are approximately 2 ns in duration with emission currents of several mA, and the train contains up to 6 pulses at a frequency of 100 MHz. Particle-in-cell simulation is used to predict the characteristic of the current pulse train generated from a single carbon fiber field emission cathode using the same technique.

  14. Electron Cloud with Inverted Beam Screens

    E-Print Network [OSTI]

    Maury Cuna, H

    2011-01-01T23:59:59.000Z

    We report the results of computer simulations studying the effect of wrongly oriented LHC beam screens on the local electron-cloud heat load and density. At 3.5 or 7-TeV energy and for maximum secondary emission-yield values below 1.5, with the inverted sawtooth orientation about ten times higher heat load is expected than for the standard orientation, and the wrongly oriented sawtooth chambers could lead to a local heat-load bottleneck during the process of surface conditioning at 25-ns bunch spacing. The available cooling margin can be significantly increased by correcting the sawtooth orientations at least for two dipole magnets in LHC arc cells 26 and 32 R3, in order that there be no half-cell cooling loop containing more than one inverted screen.

  15. Electron beam magnetic switch for a plurality of free electron lasers

    DOE Patents [OSTI]

    Schlitt, Leland G. (Livermore, CA)

    1984-01-01T23:59:59.000Z

    Apparatus for forming and utilizing a sequence of electron beam segments, each of the same temporal length (substantially 15 nsec), with consecutive beams being separated by a constant time interval of the order of 3 nsec. The beam sequence is used for simultaneous inputs to a plurality of wiggler magnet systems that also accept the laser beams to be amplified by interaction with the co-propagating electron beams. The electron beams are arranged substantially in a circle to allow proper distribution of and simultaneous switching out of the beam segments to their respective wiggler magnets.

  16. Quantum effects in electron beam pumped GaAs

    SciTech Connect (OSTI)

    Yahia, M. E. [Faculty of Engineering, The British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt) [Faculty of Engineering, The British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt); National Institute of Laser Enhanced Sciences (NILES), Cairo University (Egypt); Azzouz, I. M. [National Institute of Laser Enhanced Sciences (NILES), Cairo University (Egypt)] [National Institute of Laser Enhanced Sciences (NILES), Cairo University (Egypt); Moslem, W. M. [Department of Physics, Faculty of Science, Port Said University, Port Said (Egypt)] [Department of Physics, Faculty of Science, Port Said University, Port Said (Egypt)

    2013-08-19T23:59:59.000Z

    Propagation of waves in nano-sized GaAs semiconductor induced by electron beam are investigated. A dispersion relation is derived by using quantum hydrodynamics equations including the electrons and holes quantum recoil effects, exchange-correlation potentials, and degenerate pressures. It is found that the propagating modes are instable and strongly depend on the electron beam parameters, as well as the quantum recoil effects and degenerate pressures. The instability region shrinks with the increase of the semiconductor number density. The instability arises because of the energetic electron beam produces electron-hole pairs, which do not keep in phase with the electrostatic potential arising from the pair plasma.

  17. 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}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.

  18. High density harp or wire scanner for particle beam diagnostics

    DOE Patents [OSTI]

    Fritsche, Craig T. (Overland Park, KS); Krogh, Michael L. (Lee's Summit, MO)

    1996-05-21T23:59:59.000Z

    A diagnostic detector head harp (23) used to detect and characterize high energy particle beams using an array of closely spaced detector wires (21), typically carbon wires, spaced less than 0.1 cm (0.040 inch) connected to a hybrid microcircuit (25) formed on a ceramic substrate (26). A method to fabricate harps (23) to obtain carbon wire spacing and density not previously available utilizing hybrid microcircuit technology. The hybrid microcircuit (25) disposed on the ceramic substrate (26) connects electrically between the detector wires (21) and diagnostic equipment (37) which analyzes pulses generated in the detector wires (21) by the high energy particle beams.

  19. High density harp or wire scanner for particle beam diagnostics

    DOE Patents [OSTI]

    Fritsche, C.T.; Krogh, M.L.

    1996-05-21T23:59:59.000Z

    Disclosed is a diagnostic detector head harp used to detect and characterize high energy particle beams using an array of closely spaced detector wires, typically carbon wires, spaced less than 0.1 cm (0.040 inch) connected to a hybrid microcircuit formed on a ceramic substrate. A method to fabricate harps to obtain carbon wire spacing and density not previously available utilizing hybrid microcircuit technology. The hybrid microcircuit disposed on the ceramic substrate connects electrically between the detector wires and diagnostic equipment which analyzes pulses generated in the detector wires by the high energy particle beams. 6 figs.

  20. Measurement of Neutral Particle Contamination in the MICE Muon Beam

    E-Print Network [OSTI]

    Rob Roy Fletcher; Linda Coney; Gail Hanson

    2011-05-03T23:59:59.000Z

    The Muon Ionization Cooling Experiment (MICE) is being built at the ISIS proton synchrotron at Rutherford Appleton Laboratory (RAL) to measure ionization cooling of a muon beam. During recent data-taking, it was determined that there is a significant background contamination of neutral particles populating the MICE muon beam. This contamination creates unwanted triggers in MICE, thus reducing the percentage of useful data taken during running. This paper describes the analysis done with time-of-flight detectors, used to measure and identify the source of the contamination in both positive and negative muon beams.

  1. Free electron laser with bunched relativistic electron beam and electrostatic longitudinal wiggler

    SciTech Connect (OSTI)

    Sepehri Javan, Nasser [Department of Physics, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil (Iran, Islamic Republic of)

    2010-06-15T23:59:59.000Z

    The system of the nonlinear nonstationary equations describing spatial-temporal dynamics of the amplitudes of an undulator radiation and a space charge wave of a relativistic electron beam in the resonator is obtained. The electrostatic longitudinal wiggler is considered. A bunch of the electron beam injects to the resonator, at the ends of which two mirrors are placed. After the interaction of electrons of bunch with radiation in the presence of wiggler and after amplifying electromagnetic pulse, a part of radiation is reflected back by semitransparent mirror. Then, it reaches to the initial of the system where the other mirror is placed. Synchronously, when the pulse is reflecting, the other electron bunch enters to the resonator and interacts with the pulse. This operation has simulated until saturation of growth of the electromagnetic pulse. The dynamics of the problem is simulated by the method of macro particles. The dynamics of pulse amplification, motion of the electrons, and spectra of output radiation in each stage are simulated.

  2. Electronically shielded solid state charged particle detector

    DOE Patents [OSTI]

    Balmer, D.K.; Haverty, T.W.; Nordin, C.W.; Tyree, W.H.

    1996-08-20T23:59:59.000Z

    An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite. 1 fig.

  3. Electronically shielded solid state charged particle detector

    DOE Patents [OSTI]

    Balmer, David K. (155 Coral Way, Broomfield, CO 80020); Haverty, Thomas W. (1173 Logan, Northglenn, CO 80233); Nordin, Carl W. (7203 W. 32nd Ave., Wheatridge, CO 80033); Tyree, William H. (1977 Senda Rocosa, Boulder, CO 80303)

    1996-08-20T23:59:59.000Z

    An electronically shielded solid state charged particle detector system having enhanced radio frequency interference immunity includes a detector housing with a detector entrance opening for receiving the charged particles. A charged particle detector having an active surface is disposed within the housing. The active surface faces toward the detector entrance opening for providing electrical signals representative of the received charged particles when the received charged particles are applied to the active surface. A conductive layer is disposed upon the active surface. In a preferred embodiment, a nonconductive layer is disposed between the conductive layer and the active surface. The conductive layer is electrically coupled to the detector housing to provide a substantially continuous conductive electrical shield surrounding the active surface. The inner surface of the detector housing is supplemented with a radio frequency absorbing material such as ferrite.

  4. Title of Dissertation: LASER SWITCHED ELECTRON BEAM MODULATION WITH TERAHERTZ

    E-Print Network [OSTI]

    Anlage, Steven

    ABSTRACT Title of Dissertation: LASER SWITCHED ELECTRON BEAM MODULATION WITH TERAHERTZ APPLICATIONS Jonathan Neumann, PhD 2005 Dissertation Directed By: Dr. Patrick O'Shea, Department of Electrical and Computer Engineering This dissertation describes the exploration of relativistic electron beams modulated

  5. Etching of polycrystalline diamond films by electron beam assisted plasma

    E-Print Network [OSTI]

    Rocca, Jorge J.

    Etching of polycrystalline diamond films by electron beam assisted plasma Koji Kobashi, Shigeaki) Polycrystalline diamond films were processed in a direct current plasma produced by a self-focused electron beam that the etching apparatus used was capable of forming at least a 5-mm wide pattern of polycrystalline diamond film

  6. Electron beam melting and refining state of the art 1995

    SciTech Connect (OSTI)

    Bakish, R. [ed.

    1995-12-31T23:59:59.000Z

    This is the proceedings of the Electron Beam Melting and Refining - State of the Art 1995 Conference. It contains 23 of the 30 scheduled papers. Papers cover an array of electron beam melting applications, from industrial plating of metal strip, through government work on manufacturing and processing fissile alloys. Separate abstracts have been prepared for articles from this proceedings.

  7. NOx reduction by electron beam-produced nitrogen atom injection

    DOE Patents [OSTI]

    Penetrante, Bernardino M. (San Ramon, CA)

    2002-01-01T23:59:59.000Z

    Deactivated atomic nitrogen generated by an electron beam from a gas stream containing more than 99% N.sub.2 is injected at low temperatures into an engine exhaust to reduce NOx emissions. High NOx reduction efficiency is achieved with compact electron beam devices without use of a catalyst.

  8. Electron Gun For Multiple Beam Klystron Using Magnetic Focusing

    DOE Patents [OSTI]

    Ives, R. Lawrence (Saratoga, CA); Miram, George (Atherton, CA); Krasnykh, Anatoly (Santa Clara, CA)

    2004-07-27T23:59:59.000Z

    An RF device comprising a plurality of drift tubes, each drift tube having a plurality of gaps defining resonant cavities, is immersed in an axial magnetic field. RF energy is introduced at an input RF port at one of these resonant cavities and collected at an output RF port at a different RF cavity. A plurality of electron beams passes through these drift tubes, and each electron beam has an individual magnetic shaping applied which enables confined beam transport through the drift tubes.

  9. Experimental Observation of Femtosecond Electron Beam Microbunching by Inverse

    E-Print Network [OSTI]

    Brookhaven National Laboratory

    Experimental Observation of Femtosecond Electron Beam Micro­bunching by Inverse Free­Electron­Laser scale of ß 2.5 ¯m by an Inverse Free Electron Laser (IFEL) accelerator was observed. The optimum Cerenkov accelerator (ICA)[5], inverse free electron laser (IFEL) [6] and plasma laser accelerators [7, 8

  10. Thermal effect on prebunched two-beam free electron laser

    SciTech Connect (OSTI)

    Mirian, N. S. [School of Particle and Accelerator Physics, Institute for Research in Fundamental Sciences (IPM), 19395-5531 Tehran (Iran, Islamic Republic of)] [School of Particle and Accelerator Physics, Institute for Research in Fundamental Sciences (IPM), 19395-5531 Tehran (Iran, Islamic Republic of); Maraghechi, B. [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)] [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)

    2013-08-15T23:59:59.000Z

    A numerical simulation in one-dimension is conducted to study the two-beam free electron laser. The fundamental resonance of the fast electron beam coincides with the fifth harmonic of the slow electron beam in order to generate extreme ultraviolet radiation. Thermal effect in the form of the longitudinal velocity spread is included in the analysis. In order to reduce the length of the wiggler, prebunched slow electron beam is considered. The evaluation of the radiation power, bunching parameter, distribution function of energy, and the distribution function of the pondermotive phase is studied. Sensitivity of the power of the fifth harmonic to the jitter in the energy difference between the two beams is also studied. A phase space is presented that shows the trapped electrons at the saturation point.

  11. Sensitivity of nonlinear harmonic generation to electron beam quality in free-electron lasers

    E-Print Network [OSTI]

    2002-01-01T23:59:59.000Z

    Jr. , Principles of Free-electron Lasers (Chapman & Hall,experiment," in Free Electron Laser Challenges II, Harold E.Beam Quality in Free-Electron Lasers* Sandra G . Biedron*f,

  12. Particle beam dynamics | Princeton Plasma Physics Lab

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

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

  13. Magnet Lattice Design for the Transmission of Power Using Particle Beams

    SciTech Connect (OSTI)

    Marley, Daniel; /North Carolina State U. /SLAC

    2012-08-24T23:59:59.000Z

    As the amount of electricity generated by renewable energy sources continues to increase, the current method of power transmission will not serve as an adequate method for transmitting power over very long distances. A new method for transmitting power is proposed using particle beams in a storage ring. Particle beams offer an incredibly energy efficient alternative to transmission lines in transmitting power over very long distances. A thorough investigation of the magnet lattice design for this storage ring is presented. The design demonstrates the ability to design a ring with stable orbits over a 381.733 km circumference. Double bend achromats and FODO cells are implemented to achieve appropriate {beta} functions and dispersion functions for 9-11 GeV electron beams.

  14. GeV electron beams from a centimetre-scale accelerator

    E-Print Network [OSTI]

    to synchrotron radiation facilities and free-electron lasers, and as modules for high-energy particle physics. Radiofrequency-based accelerators are limited to relatively low accelerating fields (10-50 MV m-1 ), requiring tens to hundreds of metres to reach the multi-GeV beam energies needed to drive radiation sources

  15. Pulsed-electron-beam melting of Fe

    SciTech Connect (OSTI)

    Knapp, J.A.; Follstaedt, D.M.

    1981-01-01T23:59:59.000Z

    Pulsed (50 nsec) electron beams with deposited energies of 1.1 to 2.3 J/cm/sup 2/ have been used to rapidly melt a surface layer of Fe. Calculations show that this range of energies produces melt depths from 0.4 to 1.2 ..mu..m and melt times of 100 to 500 nsec. Optical microscopy and SEM of pulse treated polycrystalline foils show slip traces, as well as a general smoothing of surface features which shows that melting has occurred. TEM shows that the resolidified material is bcc, and that the material within a grain is epitaxial with the substrate. TEM also shows slip traces along (110) planes, as well as a high density of dislocations, both extended and loop. At the highest energy, subgrain boundaries are observed. Some samples were implanted with 1 x 10/sup 16/ Sn/cm/sup 2/ at 150 keV. After pulse treatment, the Sn depth profile was observed to have broadened, consistent with liquid phase diffusion. The Sn had the unexpected effect of suppressing slip at the sample surface.

  16. A NEW VERSION OF A FREE ELECTRON LASER TWO BEAM ACCELERATOR

    E-Print Network [OSTI]

    Sessler, A.M.

    2008-01-01T23:59:59.000Z

    Radiation in Free Electron Laser Two-Beam Accelerator",Power 35 GHz Testing of a Free-Electron Laser and Two-BeamA New Version of a Free Electron Laser Two-Beam Accelerator

  17. Guiding and collimating fast electron beam by the quasi-static electromagnetic field array

    SciTech Connect (OSTI)

    Wang, J. [Physics Department, Fudan University, Shanghai 210433 (China); Science and Technology on Plasma Physics Laboratory, Mianyang 621900 (China); Zhao, Z. Q.; He, W. H.; Dong, K. G.; Wu, Y. C.; Zhu, B.; Zhang, T. K.; Zhang, B.; Zhang, Z. M.; Gu, Y. Q., E-mail: yqgu@caep.ac.cn [Science and Technology on Plasma Physics Laboratory, Mianyang 621900 (China); Cao, L. H. [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China)

    2014-10-15T23:59:59.000Z

    A guidance and collimation scheme for fast electron beam in a traverse periodic quasi-static electromagnetic field array is proposed with the semi-analytic method and the particle-in-cell simulation. The sheath electric fields on the surfaces of nanowires and the magnetic fields around the nanowires form a traverse periodic quasi-static electromagnetic field array. Therefore, most of the fast electrons are confined at the nanowire surfaces and transport forward. More importantly, due to the divergent property of the beams, the magnitudes of the generated fields decrease with the target depth. The lateral momenta of the electrons convert into the forward momenta through Lorenz force, and they cannot recover their initial values. Therefore, the fast electrons can be guided and collimated efficiently in the gaps between the nanowires. In our particle-in-cell simulations, the observed guiding efficiency exceeds 80% compared with the reference target.

  18. NANOSTRUCTURE PATTERNING UNDER ENERGETIC PARTICLE BEAM IRRADIATION

    SciTech Connect (OSTI)

    Wang, Lumin [Regents of the University of Michigan; Lu, Wei [Regents of the University of Michigan

    2013-01-31T23:59:59.000Z

    Energetic ion bombardment can lead to the development of complex and diverse nanostructures on or beneath the material surface through induced self-organization processes. These self-organized structures have received particular interest recently as promising candidates as simple, inexpensive, and large area patterns, whose optical, electronic and magnetic properties are different from those in the bulk materials [1-5]. Compared to the low mass efficiency production rate of lithographic methods, these self-organized approaches display new routes for the fabrication of nanostructures over large areas in a short processing time at the nanoscale, beyond the limits of lithography [1,4]. Although it is believed that surface nanostructure formation is based on the morphological instability of the sputtered surface, driven by a kinetic balance between roughening and smoothing actions [6,7], the fundamental mechanisms and experimental conditions for the formation of these nanostructures has still not been well established, the formation of the 3-D naopatterns beneath the irradiated surface especially needs more exploration. During the last funding period, we have focused our efforts on irradiation-induced nanostructures in a broad range of materials. These structures have been studied primarily through in situ electron microscopy during electron or ion irradiation. In particular, we have performed studies on 3-D void/bubble lattices (in metals and CaF2), embedded sponge-like porous structure with uniform nanofibers in irradiated semiconductors (Ge, GaSb, and InSb), 2-D highly ordered pattern of nanodroplets (on the surface of GaAs), hexagonally ordered nanoholes (on the surface of Ge), and 1-D highly ordered ripple and periodic arrays (of Cu nanoparticles) [3,8-11]. The amazing common feature in those nanopatterns is the uniformity of the size of nanoelements (nanoripples, nanodots, nanovoids or nanofibers) and the distance separating them. Our research focuses on the understanding of fundamental scientific basis for the irradiation-induced self-organization processes. The fundamental physical mechanisms underlying ordered pattern formation, which include defect production and migration, ion sputtering, redeposition, viscous flow and diffusion, are investigated through a combination of modeling and in situ and ex-situ observations [3,9,11]. In addition, these nanostructured materials exhibit considerable improvement of optical properties [9,12,13]. For example, patterned Ge with a hexagonally ordered, honeycomb-like structure of nanoscale holes possesses a high surface area and a considerably blue-shifted energy gap [9], and oxidation of ordered Ga droplets shows noticeable enhancement of optical transmission [12]. This research has addressed nanopattern formation in a variety of materials under ion bombardment and provided a fundamental understanding of the dynamic mechanisms involved. In addition, have also stared to systematically investigate pattern formation under ion irradiation for more systems with varied experimental conditions and computation, including the collaboration with Dr. Veena Tikare of Sandia National Laboratory with a hybrid computation method at the ending this grant. A more detailed relationship between nanostructure formation and experimental conditions will be revealed with our continued efforts.

  19. Virtual mask digital electron beam lithography

    DOE Patents [OSTI]

    Baylor, Larry R. (Farragut, TN); Thomas, Clarence E. (Knoxville, TN); Voelkl, Edgar (Oak Ridge, TN); Moore, James A. (Powell, TN); Simpson, Michael L. (Knoxville, TN); Paulus, Michael J. (Knoxville, TN)

    1999-01-01T23:59:59.000Z

    Systems and methods for direct-to-digital holography are described. An apparatus includes a laser; a beamsplitter optically coupled to the laser; a reference beam mirror optically coupled to the beamsplitter; an object optically coupled to the beamsplitter, a focusing lens optically coupled to both the reference beam mirror and the object; and a digital recorder optically coupled to the focusing lens. A reference beam is incident upon the reference beam mirror at a non-normal angle, and the reference beam and an object beam are focused by the focusing lens at a focal plane of the digital recorder to form an image. The systems and methods provide advantages in that computer assisted holographic measurements can be made.

  20. A compact, versatile low-energy electron beam ion source

    SciTech Connect (OSTI)

    Zschornack, G., E-mail: g.zschornack@hzdr.de [Department of Physics, Dresden University of Technology, 01062 Dresden, Germany and Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, 01328 Dresden (Germany); König, J.; Schmidt, M.; Thorn, A. [DREEBIT GmbH, 01109 Dresden (Germany)] [DREEBIT GmbH, 01109 Dresden (Germany)

    2014-02-15T23:59:59.000Z

    A new compact Electron Beam Ion Source, the Dresden EBIT-LE, is introduced as an ion source working at low electron beam energies. The EBIT-LE operates at an electron energy ranging from 100 eV to some keV and can easily be modified to an EBIT also working at higher electron beam energies of up to 15 keV. We show that, depending on the electron beam energy, electron beam currents from a few mA in the low-energy regime up to about 40 mA in the high-energy regime are possible. Technical solutions as well as first experimental results of the EBIT-LE are presented. In ion extraction experiments, a stable production of low and intermediate charged ions at electron beam energies below 2 keV is demonstrated. Furthermore, X-ray spectroscopy measurements confirm the possibility of using the machine as a source of X-rays from ions excited at low electron energies.

  1. Interfacial Properties of Electron Beam Cured Composites

    SciTech Connect (OSTI)

    Eberle, C.C.

    1999-12-30T23:59:59.000Z

    The objectives of the CRADA are to: Confirm that fiber-resin adhesion is responsible for the observed poor shear properties; Determine the mechanism(s) responsible for poor adhesion between carbon fibers and epoxy resins after e-beam curing; Develop and evaluate resin systems and fiber treatments to improve the properties of e-beam cured, carbon-fiber-reinforced composites; and Develop refined methods for processing e-beam cured, carbon-fiber-reinforced composites.

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

    SciTech Connect (OSTI)

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

    2010-05-21T23:59:59.000Z

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

  3. A PLASMA CHANNEL BEAM CONDITIONER FOR A FREE ELECTRON LASER

    E-Print Network [OSTI]

    Wurtele, Jonathan

    A PLASMA CHANNEL BEAM CONDITIONER FOR A FREE ELECTRON LASER G. Penn , A.M. Sessler, J.S. Wurtele of free electron lasers (FELs) can be dramatically improved. Under certain con- ditions, the FEL can transverse action and energy, has been shown to be advantageous for free electron laser (FEL) performance [1

  4. Whistler wave generation by non-gyrotropic, relativistic, electron beams

    SciTech Connect (OSTI)

    Skender, M.; Tsiklauri, D. [School of Physics and Astronomy, Queen Mary University of London, 327 Mile End Road, London E1 4NS (United Kingdom)] [School of Physics and Astronomy, Queen Mary University of London, 327 Mile End Road, London E1 4NS (United Kingdom)

    2014-04-15T23:59:59.000Z

    Particle-in-cell code, EPOCH, is used for studying features of the wave component evident to propagate backwards from the front of the non-gyrotropic, relativistic beam of electrons injected in the Maxwellian, magnetised background plasma with decreasing density profile. According to recent findings presented in Tsiklauri [Phys. Plasmas 18, 052903 (2011)], Schmitz and Tsiklauri [Phys. Plasmas 20, 062903 (2013)], and Pechhacker and Tsiklauri [Phys. Plasmas 19, 112903 (2012)], in a 1.5-dimensional magnetised plasma system, the non-gyrotropic beam generates freely escaping electromagnetic radiation with properties similar to the Type-III solar radio bursts. In this study, the backwards propagating wave component evident in the perpendicular components of the electromagnetic field in such a system is presented for the first time. Background magnetic field strength in the system is varied in order to prove that the backwards propagating wave's frequency, prescribed by the whistler wave dispersion relation, is proportional to the specified magnetic field. Moreover, the identified whistlers are shown to be generated by the normal Doppler-shifted relativistic resonance. Large fraction of the energy of the perpendicular electromagnetic field components is found to be carried away by the whistler waves, while a small but sufficient fraction is going into L- and R-electromagnetic modes.

  5. Achromatic and Isochronous Electron Beam Transport for Free Electron Lasers

    E-Print Network [OSTI]

    Bengtsson, J.

    2011-01-01T23:59:59.000Z

    Beamlines for Free Electron Lasers," LBL-28880 Preprint (Thirteenth mtemational Free Electron Laser Conference, SantaTransport for Tunable Free Electron Lasers 1. Bengtsson and

  6. Transmission of Megawatt Relativistic Electron Beams Through Millimeter Apertures

    SciTech Connect (OSTI)

    Arizona State University; Arizona State University; JLAB; MIT; College of William and Mary, JLAB; MIT; JLAB; JLAB; MIT; MIT; Hampton University; MIT; JLAB; MIT; JLAB; MIT; MIT; JLAB; MIT; JLAB; JLAB

    2013-10-01T23:59:59.000Z

    High power, relativistic electron beams from energy recovery linacs have great potential to realize new experimental paradigms for pioneering research in fundamental and applied research. A major design consideration for these new generation of experimental capabilities is the understanding of the halo associated with these bright, intense beams. In this Letter, we report on measurements performed using the 100 MeV, 430 kWatt CW electron beam from the energy recovery linac at the Jeff#11;erson Laboratory's Free Electron Laser facility as it traversed a set of small apertures in a 127 mm long aluminum block. Thermal measurements of the block together with neutron measurements near the beam-target interaction point yielded a consistent understanding of the beam losses. These were determined to be 3 ppm through a 2 mm diameter aperture and were maintained during a 7 hour continuous run.

  7. Origin and control of magnetic exchange coupling in between focused electron beam deposited cobalt nanostructures

    SciTech Connect (OSTI)

    Nikulina, E.; Idigoras, O.; Porro, J. M.; Berger, A. [CIC nanoGUNE Consolider, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian (Spain)] [CIC nanoGUNE Consolider, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian (Spain); Vavassori, P.; Chuvilin, A. [CIC nanoGUNE Consolider, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian (Spain) [CIC nanoGUNE Consolider, Tolosa Hiribidea 76, 20018 Donostia-San Sebastian (Spain); Ikerbasque, Basque Foundation for Science, Alameda Urquijo 36-5, 48011 Bilbao (Spain)

    2013-09-16T23:59:59.000Z

    We demonstrate the existence and control of inter-particle magnetic exchange coupling in densely packed nanostructures fabricated by focused electron beam induced deposition. With Xe beam post-processing, we have achieved the controlled reduction and eventual elimination of the parasitic halo-like cobalt deposits formed in the proximity of intended nanostructures, which are the identified source of the magnetic exchange coupling. The elimination of the halo-mediated exchange coupling is demonstrated by magnetic measurements using Kerr microscopy on Co pillar arrays. Electron microscopy studies allowed us to identify the mechanisms underlying this process and to verify the efficiency and opportunities of the described nano-scale fabrication approach.

  8. Electron gun for a multiple beam klystron with magnetic compression of the electron beams

    DOE Patents [OSTI]

    Ives, R. Lawrence; Tran, Hien T; Bui, Thuc; Attarian, Adam; Tallis, William; David, John; Forstall, Virginia; Andujar, Cynthia; Blach, Noah T; Brown, David B; Gadson, Sean E; Kiley, Erin M; Read, Michael

    2013-10-01T23:59:59.000Z

    A multi-beam electron gun provides a plurality N of cathode assemblies comprising a cathode, anode, and focus electrode, each cathode assembly having a local cathode axis and also a central cathode point defined by the intersection of the local cathode axis with the emitting surface of the cathode. Each cathode is arranged with its central point positioned in a plane orthogonal to a device central axis, with each cathode central point an equal distance from the device axis and with an included angle of 360/N between each cathode central point. The local axis of each cathode has a cathode divergence angle with respect to the central axis which is set such that the diverging magnetic field from a solenoidal coil is less than 5 degrees with respect to the projection of the local cathode axis onto a cathode reference plane formed by the device axis and the central cathode point, and the local axis of each cathode is also set such that the angle formed between the cathode reference plane and the local cathode axis results in minimum spiraling in the path of the electron beams in a homogenous magnetic field region of the solenoidal field generator.

  9. Electron vortex beams in a magnetic field and spin filter

    E-Print Network [OSTI]

    Debashree Chowdhury; Banasri Basu; Pratul Bandyopadhyay

    2015-02-25T23:59:59.000Z

    We investigate the propagation of electron vortex beams in a magnetic field. It is pointed out that when electron vortex beams carrying orbital angular momentum propagate in a magnetic field, the Berry curvature associated with the scalar electron moving in a cyclic path around the vortex line is modified from that in free space. This alters the spin-orbit interaction, which affects the propagation of nonparaxial beams. The electron vortex beams with tilted vortex lead to spin Hall effect in free space. In presence of a magnetic field in time space we have spin filtering such that either positive or negative spin states emerge in spin Hall currents with clustering of spin $\\frac{1}{2}$ states.

  10. Active negative-index metamaterial powered by an electron beam

    E-Print Network [OSTI]

    Shapiro, Michael

    An active negative index metamaterial that derives its gain from an electron beam is introduced. The metamaterial consists of a stack of equidistant parallel metal plates perforated by a periodic array of holes shaped as ...

  11. Transmission of Megawatt Relativistic Electron Beams through Millimeter Apertures

    E-Print Network [OSTI]

    Alarcon, R.

    High-power, relativistic electron beams from energy-recovering linacs have great potential to realize new experimental paradigms for pioneering innovation in fundamental and applied research. A major design consideration ...

  12. Achieving sub-10-nm resolution using scanning electron beam lithography

    E-Print Network [OSTI]

    Cord, Bryan M. (Bryan Michael), 1980-

    2009-01-01T23:59:59.000Z

    Achieving the highest possible resolution using scanning-electron-beam lithography (SEBL) has become an increasingly urgent problem in recent years, as advances in various nanotechnology applications have driven demand for ...

  13. 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

  14. Method and system for treating an interior surface of a workpiece using a charged particle beam

    DOE Patents [OSTI]

    Swenson, David Richard (Georgetown, MA)

    2007-05-23T23:59:59.000Z

    A method and system of treating an interior surface on an internal cavity of a workpiece using a charged particle beam. A beam deflector surface of a beam deflector is placed within the internal cavity of the workpiece and is used to redirect the charged particle beam toward the interior surface to treat the interior surface.

  15. Pulsed particle beam vacuum-to-air interface

    DOE Patents [OSTI]

    Cruz, G.E.; Edwards, W.F.

    1987-06-18T23:59:59.000Z

    A vacuum-to-air interface is provided for a high-powered, pulsed particle beam accelerator. The interface comprises a pneumatic high speed gate valve, from which extends a vacuum-tight duct, that terminates in an aperture. Means are provided for periodically advancing a foil strip across the aperture at the repetition rate of the particle pulses. A pneumatically operated hollow sealing band urges foil strip, when stationary, against and into the aperture. Gas pressure means periodically lift off and separate foil strip from aperture, so that it may be readily advanced. 5 figs.

  16. Electron beam skull melting and refining of secondary copper

    SciTech Connect (OSTI)

    Bychkov, Y.; Ladokhin, S. [Donetskvtortsvetmet, Donetsk (Ukraine)

    1995-12-31T23:59:59.000Z

    Electron Beam Melting is the most efficient technology for metals and alloys refining. For secondary metals processing the Electron Beam Skull Melting (EBSM) with the electromagnetic stirring (EMS) of melt in the crucible was shown to be the most appropriate. The copper produced by EBSM with EMS possesses higher density and electric conductivity in comparison with other refining methods. The details for high power electrical machines were cast of the copper waste refined by EBSM technology.

  17. Electron Beam Collimation for the Next Generation Light Source

    SciTech Connect (OSTI)

    Steier, C.; Emma, P.; Nishimura, H.; Papadopoulos, C.; Sannibale, F.

    2013-05-20T23:59:59.000Z

    The Next Generation Light Source will deliver high (MHz) repetition rate electron beams to an array of free electron lasers. Because of the significant average current in such a facility, effective beam collimation is extremely important to minimize radiation damage to undulators, prevent quenches of superconducting cavities, limit dose rates outside of the accelerator tunnel and prevent equipment damage. This paper describes the early conceptual design of a collimation system, as well as initial results of simulations to test its effectiveness.

  18. An electron-beam programmable erasable memory device

    E-Print Network [OSTI]

    Wang, Kang-Huai

    1984-01-01T23:59:59.000Z

    AN ELECTRON-BEAM PROGRAMMABLE ERASABLE MEMORY DEVICE A Thesis by RANG-HUAI WANG Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement for the degree of MASTER OP SCIENCE August 1984 Major... Subject: Electrical Engineering AN ELECTRON-BEAM PROGRAMMABLE ERASABLE MEMORY DEVICE A Thesis by Kang-Huai Wang Approved as to style and content by: Dona L. Parker (Chairman of Committee) Mark H. Weicho d (Member) omas . air, III (Member...

  19. Particle Beam Stability in the Hollow Plasma Channel Wake Field Accelerator

    E-Print Network [OSTI]

    Wurtele, Jonathan

    Particle Beam Stability in the Hollow Plasma Channel Wake Field Accelerator Carl B. Schroeder1 structure is the transverse instability of the particle beam. INTRODUCTION Plasma-based accelerators have. The electromagnetic wake field response of a hollow plasma channel to a driver (laser or charged particle beam

  20. Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams C. B. Schroeder, E of an intense laser or the space-charge force of a charged particle beam. The implications for accelerator-charge force of a charged particle beam. Laser-driven plasma accelerators (LPAs) were first proposed in 1979

  1. Electron beam related advances at ATF

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

    to cavity loading. Compensation of the dispersion is needed at the level of a few mm. * Plasma Wakefield experiment needs extra small focus (10 micron) of the bunched beam...

  2. 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.

  3. Note: Characteristic beam parameter for the line electron gun

    SciTech Connect (OSTI)

    Iqbal, M. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan) [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Islam, G. U. [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan)] [Centre for High Energy Physics, University of the Punjab, Lahore 45590 (Pakistan); Zhou, Z.; Chi, Y. [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)] [Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China)

    2013-11-15T23:59:59.000Z

    We have optimized the beam parameters of line source electron gun using Stanford Linear Accelerator Centre electron beam trajectory program (EGUN), utilizing electrostatic focusing only. We measured minimum beam diameter as 0.5 mm that corresponds to power density of 68.9 kW/cm{sup 2} at 13.5 mm in the post-anode region which is more than two-fold (33 kW/cm{sup 2}), of the previously reported results. The gun was operated for the validation of the theoretical results and found in good agreement. The gun is now without any magnetic and electrostatic focusing thus much simpler and more powerful.

  4. Energy Spread Reduction of Electron Beams Produced via Laser Wake

    SciTech Connect (OSTI)

    Pollock, B

    2012-03-19T23:59:59.000Z

    Laser wakefield acceleration of electrons holds great promise for producing ultra-compact stages of GeV scale, high quality electron beams for applications such as x-ray free electron lasers and high energy colliders. Ultra-high intensity laser pulses can be self-guided by relativistic plasma waves over tens of vacuum diffraction lengths, to give >1 GeV energy in cm-scale low density plasma using ionization-induced injection to inject charge into the wake at low densities. This thesis describes a series of experiments which investigates the physics of LWFA in the self-guided blowout regime. Beginning with high density gas jet experiments the scaling of the LWFA-produced electron beam energy with plasma electron density is found to be in excellent agreement with both phenomenological theory and with 3-D PIC simulations. It is also determined that self-trapping of background electrons into the wake exhibits a threshold as a function of the electron density, and at the densities required to produce electron beams with energies exceeding 1 GeV a different mechanism is required to trap charge into low density wakes. By introducing small concentrations of high-Z gas to the nominal He background the ionization-induced injection mechanism is enabled. Electron trapping is observed at densities as low as 1.3 x 10{sup 18} cm{sup -3} in a gas cell target, and 1.45 GeV electrons are demonstrated for the first time from LWFA. This is currently the highest electron energy ever produced from LWFA. The ionization-induced trapping mechanism is also shown to generate quasi-continuous electron beam energies, which is undesirable for accelerator applications. By limiting the region over which ionization-induced trapping occurs, the energy spread of the electron beams can be controlled. The development of a novel two-stage gas cell target provides the capability to tailor the gas composition in the longitudinal direction, and confine the trapping process to occur only in a limited, defined region. Using this technique a 460 MeV electron beam was produced with an energy spread of 5%. This technique is directly scalable to multi-GeV electron beam generation with sub-percent energy spreads.

  5. Laser-driven deflection arrangements and methods involving charged particle beams

    DOE Patents [OSTI]

    Plettner, Tomas (San Ramon, CA); Byer, Robert L. (Stanford, CA)

    2011-08-09T23:59:59.000Z

    Systems, methods, devices and apparatus are implemented for producing controllable charged particle beams. In one implementation, an apparatus provides a deflection force to a charged particle beam. A source produces an electromagnetic wave. A structure, that is substantially transparent to the electromagnetic wave, includes a physical structure having a repeating pattern with a period L and a tilted angle .alpha., relative to a direction of travel of the charged particle beam, the pattern affects the force of the electromagnetic wave upon the charged particle beam. A direction device introduces the electromagnetic wave to the structure to provide a phase-synchronous deflection force to the charged particle beam.

  6. Electron cyclotron beam measurement system in the Large Helical Device

    SciTech Connect (OSTI)

    Kamio, S., E-mail: kamio@nifs.ac.jp; Takahashi, H.; Kubo, S.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Ito, S.; Kobayashi, S.; Mizuno, Y.; Okada, K.; Osakabe, M.; Mutoh, T. [National Institute for Fusion Science, Toki 509-5292 (Japan)

    2014-11-15T23:59:59.000Z

    In order to evaluate the electron cyclotron (EC) heating power inside the Large Helical Device vacuum vessel and to investigate the physics of the interaction between the EC beam and the plasma, a direct measurement system for the EC beam transmitted through the plasma column was developed. The system consists of an EC beam target plate, which is made of isotropic graphite and faces against the EC beam through the plasma, and an IR camera for measuring the target plate temperature increase by the transmitted EC beam. This system is applicable to the high magnetic field (up to 2.75 T) and plasma density (up to 0.8 × 10{sup 19} m{sup ?3}). This system successfully evaluated the transmitted EC beam profile and the refraction.

  7. Upgrade of the electron beam ion trap in Shanghai

    SciTech Connect (OSTI)

    Lu, D.; Yang, Y.; Xiao, J.; Shen, Y.; Fu, Y.; Wei, B.; Yao, K.; Hutton, R.; Zou, Y., E-mail: zouym@fudan.edu.cn [The Key Lab of Applied Ion Beam Physics, Ministry of Education, 200433 Shanghai (China); Shanghai EBIT Lab, Institute of Modern Physics, Fudan University, 200433 Shanghai (China)

    2014-09-15T23:59:59.000Z

    Over the last few years the Shanghai electron beam ion trap (EBIT) has been successfully redesigned and rebuilt. The original machine, developed under collaboration with the Shanghai Institute of Applied Physics, first produced an electron beam in 2005. It could be tuned with electron energies between 1 and 130 keV and beam current up to 160 mA. After several years of operation, it was found that several modifications for improvements were necessary to reach the goals of better electron optics, higher photon detection, and ion injection efficiencies, and more economical running costs. The upgraded Shanghai-EBIT is made almost entirely from Ti instead of stainless steel and achieves a vacuum of less than 10{sup ?10} Torr, which helps to minimize the loss of highly changed ions through charge exchange. Meanwhile, a more compact structure and efficient cryogenic system, and excellent optical alignment have been of satisfactory. The magnetic field in the central trap region can reach up till 4.8 T with a uniformity of 2.77 × 10{sup ?4}. So far the upgraded Shanghai-EBIT has been operated up to an electron energy of 151 keV and a beam current of up to 218 mA, although promotion to even higher energy is still in progress. Radiation from ions as highly charged as Xe{sup 53+,} {sup 54+} has been produced and the characterization of current density is estimated from the measured electron beam width.

  8. Measurement of Electron Beam Polarization from Unstrained Bulk GaAs via Two Photon Photoemission

    E-Print Network [OSTI]

    Gay, Timothy J.

    the Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab, where the polarized electron beamMeasurement of Electron Beam Polarization from Unstrained Bulk GaAs via Two Photon Photoemission Collections Journals About Contact us My IOPscience #12;Measurement of Electron Beam Polarization from

  9. Course Notes: United States Particle Accelerator School Beam Physics with Intense Space-Charge

    E-Print Network [OSTI]

    Barnard, J.J.

    2008-01-01T23:59:59.000Z

    of. the 1991 Particle Accelerator Conference (Ref. [3]), p.of the l J J3 Particle Accelerator Conference, Washington,Beam Physics, US Particle Accelerator School Notes, http://

  10. Physics of Neutralization of Intense Charged Particle Beam Pulses by a Background Plasma

    SciTech Connect (OSTI)

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

    2009-09-03T23:59:59.000Z

    Neutralization and focusing of intense charged particle beam pulses by a background plasma 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.

  11. A numerical model and scaling relationship for energetic electron beams propagating in air

    SciTech Connect (OSTI)

    Fernsler, R. F.; Slinker, S. P. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Lambrakos, S. G. [Materials Science and Technology Division, Naval Research Laboratory, Washington, DC 20375 (United States)

    2008-09-15T23:59:59.000Z

    Scaling relationships for energy loss and scattering are combined with a particle code to construct a purely algebraic expression for the energy deposited by an energetic electron beam injected into field-free homogeneous air. An algebraic formulation is possible because the mean free paths for the major collisional processes depend similarly on density and energy above 1 keV. Accordingly, the spatial behavior of an initially cold pencil beam is approximately self-similar when expressed in terms of the nominal beam range, provided the beam energy at injection exceeds several keV. Since a warm and broad beam can always be decomposed into a series of cold pencil beams, the total energy deposited can be obtained through a simple sum. With such a model, the ionization and excitation generated by a beam can be computed quickly and easily at every point in space. Similar formulations can be developed for other media using particle codes or experimental data. In liquids or solids, the energy deposited is quickly converted to heat and ultimately to melting and/or vaporization of the material.

  12. Electron and photon beams interacting with plasma

    E-Print Network [OSTI]

    Strathclyde, University of

    -amplitude plasma waves are dense, ultra-short relativistic electron bunches (Chen et al. 1985) or intense laser A comparison is made between the interaction of electron bunches and intense laser pulses with plasma. The laser pulse is modelled with photon kinetic theory, i.e. a representation of the electromagnetic field

  13. Tomographic determination of the power distribution in electron beams

    DOE Patents [OSTI]

    Teruya, Alan T. (Livermore, CA); Elmer, John W. (Pleasanton, CA)

    1996-01-01T23:59:59.000Z

    A tomographic technique for determining the power distribution of an electron beam using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams. A refractory metal disk with a number of radially extending slits is placed above a Faraday cup. The beam is swept in a circular pattern so that its path crosses each slit in a perpendicular manner, thus acquiring all the data needed for a reconstruction in one circular sweep. Also, a single computer is used to generate the signals actuating the sweep, to acquire that data, and to do the reconstruction, thus reducing the time and equipment necessary to complete the process.

  14. 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.

  15. Electron Beam Irradiation for Improving Safety of Fruits and Vegetables

    E-Print Network [OSTI]

    Adavi, Megha Sarthak

    2012-07-16T23:59:59.000Z

    to pathogens. Conventional techniques of sanitizing washes may not be effective since the organic matter released from the fresh produce use up the free chlorine thus reducing the sanitizing potential of wash water just when it is needed most and a heat... treatment step to kill pathogens cannot be applied if the purpose is to consume fresh produce. Electron beam (e-beam) irradiation was used to treat cut cantaloupe, cut roma tomatoes, baby spinach, romaine lettuce which were surface inoculated with a...

  16. 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.

  17. Electron Beam Transport in Advanced Plasma Wave Accelerators

    SciTech Connect (OSTI)

    Williams, Ronald L

    2013-01-31T23:59:59.000Z

    The primary goal of this grant was to develop a diagnostic for relativistic plasma wave accelerators based on injecting a low energy electron beam (5-50keV) perpendicular to the plasma wave and observing the distortion of the electron beam's cross section due to the plasma wave's electrostatic fields. The amount of distortion would be proportional to the plasma wave amplitude, and is the basis for the diagnostic. The beat-wave scheme for producing plasma waves, using two CO2 laser beam, was modeled using a leap-frog integration scheme to solve the equations of motion. Single electron trajectories and corresponding phase space diagrams were generated in order to study and understand the details of the interaction dynamics. The electron beam was simulated by combining thousands of single electrons, whose initial positions and momenta were selected by random number generators. The model was extended by including the interactions of the electrons with the CO2 laser fields of the beat wave, superimposed with the plasma wave fields. The results of the model were used to guide the design and construction of a small laboratory experiment that may be used to test the diagnostic idea.

  18. Post-Disruptive Runaway Electron Beam in COMPASS Tokamak

    E-Print Network [OSTI]

    Vlainic, Milos; Cavalier, Jordan; Weinzettl, Vladimir; Paprok, Richard; Imrisek, Martin; Ficker, Ondrej; Noterdaeme, Jean-Marie

    2015-01-01T23:59:59.000Z

    For ITER-relevant runaway electron studies, such as suppression, mitigation, termination and/or control of runaway beam, obtaining the runaway electrons after the disruption is important. In this paper we report on the first achieved discharges with post-disruptive runaway electron beam, entitled "runaway plateau", in the COMPASS tokamak. The runaway plateau is produced by massive gas injection of argon. Almost all of the disruptions with runaway electron plateaus occurred during the plasma current ramp-up phase. Comparison between the Ar injection discharges with and without plateau has been done for various parameters. Parametrisation of the discharges shows that COMPASS disruptions fulfill the range of parameters important for the runaway plateau occurrence. These parameters include electron density, electric field, disruption speed, effective safety factor, maximum current quench electric field. In addition to these typical parameters, the plasma current value just before the massive gas injection surpris...

  19. SU-D-19A-04: Parameter Characterization of Electron Beam Monte Carlo Phase Space of TrueBeam Linacs

    SciTech Connect (OSTI)

    Rodrigues, A; Yin, F; Wu, Q [Duke University Medical Center, Durham, NC (United States); Medical Physics Graduate Program, Duke University Medical Center, Durham, NC (United States); Sawkey, D [Varian Medical Systems, Palo Alto, CA (United States)

    2014-06-01T23:59:59.000Z

    Purpose: For TrueBeam Monte Carlo simulations, Varian does not distribute linac head geometry and material compositions, instead providing a phase space file (PSF) for the users. The PSF has a finite number of particle histories and can have very large file size, yet still contains inherent statistical noises. The purpose of this study is to characterize the electron beam PSF with parameters. Methods: The PSF is a snapshot of all particles' information at a given plane above jaws including type, energy, position, and directions. This study utilized a preliminary TrueBeam PSF, of which validation against measurement is presented in another study. To characterize the PSF, distributions of energy, position, and direction of all particles are analyzed as piece-wise parameterized functions of radius and polar angle. Subsequently, a pseudo PSF was generated based on this characterization. Validation was assessed by directly comparing the true and pseudo PSFs, and by using both PSFs in the down-stream MC simulations (BEAMnrc/DOSXYZnrc) and comparing dose distributions for 3 applicators at 15 MeV. Statistical uncertainty of 4% was limited by the number of histories in the original PSF. Percent depth dose (PDD) and orthogonal (PRF) profiles at various depths were evaluated. Results: Preliminary results showed that this PSF parameterization was accurate, with no visible differences between original and pseudo PSFs except at the edge (6 cm off axis), which did not impact dose distributions in phantom. PDD differences were within 1 mm for R{sub 7} {sub 0}, R{sub 5} {sub 0}, R{sub 3} {sub 0}, and R{sub 1} {sub 0}, and PRF field size and penumbras were within 2 mm. Conclusion: A PSF can be successfully characterized by distributions for energy, position, and direction as parameterized functions of radius and polar angles; this facilitates generating sufficient particles at any statistical precision. Analyses for all other electron energies are under way and results will be included in the presentation.

  20. Ultra-bright pulsed electron beam with low longitudinal emittance

    DOE Patents [OSTI]

    Zolotorev, Max (Oakland, CA)

    2010-07-13T23:59:59.000Z

    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 has been described. The source makes use of Cs atoms in an atomic beam. The source is cycled beginning with a laser pulse that excites a single Cs atom on average to a band of high-lying Rydberg nP states. The resulting valence electron Rydberg wave packet evolves in a nearly classical Kepler orbit. When the electron reaches apogee, an electric field pulse is applied that ionizes the atom and accelerates the electron away from its parent ion. The collection of electron wave packets thus generated in a series of cycles can occupy a phase volume near the quantum limit and it can possess very high brightness. Each wave packet can exhibit a considerable degree of coherence.

  1. Temporal process of plasma discharge by an electron beam

    SciTech Connect (OSTI)

    Sugawa, M.; Sugaya, R.; Isobe, S.; Kumar, A. [Department of Physics, Faculty of Science, Ehime University, Matsuyama 790 (Japan); Honda, H. [Institute of Laser Engineering, Osaka University, Suita, Osaka 565 (Japan)

    1996-05-01T23:59:59.000Z

    The process of the plasma discharge due to an electron beam is experimentally investigated. A pulse ({approximately}540 {mu}s) of an electron beam (0.5{endash}1.5 keV, {le}20 mA) is injected into argon gas (5{times}10{sup {minus}5}{endash}5{times}10{sup {minus}4} Torr) in a magnetic field (50{endash}300 G). The discharge based on a gas break down occurs cascade-likely in time. The gas beak down with some steps is explained by the two stream instability of an electron beam-plasma system, from the observation of the temporal evolution of the frequency spectra (0{endash}3.0 GHz) of the instability and the measurement of the temporal plasma density and temperature. {copyright} {ital 1996 American Institute of Physics.}

  2. Portable radiography system using a relativistic electron beam

    DOE Patents [OSTI]

    Hoeberling, R.F.

    1987-09-22T23:59:59.000Z

    A portable radiographic generator is provided with an explosive magnetic flux compression generator producing the high voltage necessary to generate a relativistic electron beam. The relativistic electron beam is provided with target materials which generates the desired radiographic pulse. The magnetic flux compression generator may require at least two conventional explosively driven generators in series to obtain a desired output voltage of at least 1 MV. The cathode and anode configuration of the diode are selected to provide a switching action wherein a high impedance load is presented to the magnetic flux compression generator when the high voltage is being generated, and thereafter switching to a low impedance load to generate the relativistic electron beam. Magnetic flux compression generators can be explosively driven and provided in a relatively compact, portable form for use with the relativistic x-ray equipment. 8 figs.

  3. Standing-Wave Free-Electron Laser Two-Beam Accelerator

    E-Print Network [OSTI]

    Sessler, Andrew M.

    2008-01-01T23:59:59.000Z

    the 11th International Free-Electron Laser Conference, Nuc!.A Standing-Wave Free-Electron Laser Two-Beam Accelerator30418 Standing-Wave Free-Electron Laser Two-Beam Accelerator

  4. Macroparticle Theory of a Standing Wave Free-Electron Laser Two-Beam Accelerator

    E-Print Network [OSTI]

    Takayama, K.

    2008-01-01T23:59:59.000Z

    Motz, Undulators and Free-Electron Laser (Clarendon Press,of a Standing Wave Free-Electron Laser Two-Beam Acceleratorof a Standing Wave Free-Electron Laser Two-Beam Accelerator

  5. Pulsed particle beam vacuum-to-air interface

    DOE Patents [OSTI]

    Cruz, Gilbert E. (Pleasanton, CA); Edwards, William F. (Livermore, CA)

    1988-01-01T23:59:59.000Z

    A vacuum-to-air interface (10) is provided for a high-powered, pulsed particle beam accelerator. The interface comprises a pneumatic high speed gate valve (18), from which extends a vacuum-tight duct (26), that termintes in an aperture (28). Means (32, 34, 36, 38, 40, 42, 44, 46, 48) are provided for periodically advancing a foil strip (30) across the aperture (28) at the repetition rate of the particle pulses. A pneumatically operated hollow sealing band (62) urges foil strip (30), when stationary, against and into the aperture (28). Gas pressure means (68, 70) periodically lift off and separate foil strip (30) from aperture (28), so that it may be readily advanced.

  6. Computer simulation of the processes at electron beam technologies

    SciTech Connect (OSTI)

    Mladenov, G.M.; Vutova, K.; Sabchevsky, S. [Institute of Electronics, Sofia (Bulgaria)

    1994-12-31T23:59:59.000Z

    The computer software packages developed in Bulgaria are among our important research results concerning EB melting and refining. (i) In the field of the gun and the beam improvement optimisation: A new approach, based on beam phase analysis, has been proposed and applied in a computer software package. The computer simulation of beam formation and transport permit to optimize technology electron guns and predict some features of the processes. A investigation of the ion compensation of the electron space charge in the beam at different technology conditions is in progress. (ii) In the electron beam refining technology. The kinetics of the impurities evaporation and refining of the low density contaminants at the drip or cold hearth melting has been investigated. Computer calculation of the component concentration changes during refinement had been developed. Analysis of main processes of the impurity transport can be studied. (iii) In the field of beam heating of the materials: Computer simulation of the heat transport is done. Deep of the melted pool, thermal distribution in the casted ingot as the temperature loading of the equipment parts are possible to be calculated.

  7. Single Crystal Diamond Beam Position Monitors with Radiofrequency Electronic Readout

    SciTech Connect (OSTI)

    Solar, B.; Graafsma, H.; Potdevin, G.; Trunk, U. [Hasylab, Deutsches Elektronen Synchroton, Hamburg (Germany); Morse, J.; Salome, M. [Instrumentation Services and Development Division, European Synchroton Radiation Facility, Grenoble (France)

    2010-06-23T23:59:59.000Z

    Over the energy range 5{approx}30 keV a suitably contacted, thin ({approx}100 {mu}m) diamond plate can be operated in situ as a continuous monitor of X-ray beam intensity and position as the diamond absorbs only a small percentage of the incident beam. Single crystal diamond is a completely homogeneous material showing fast (ns), spatially uniform signal response and negligible (beams. We report on tests made at ESRF and DESY using diamond beam position monitors of simple quadrant electrode designs with metal contacts, operated using wideband electronic readout corresponding to the RF accelerator frequency. The instrumentation for these monitors must cover a large range of operating conditions: different beam sizes, fluxes, energies and time structure corresponding to the synchrotron fill patterns. Sophisticated new RF sampling electronics can satisfy most requirements: using a modified Libera Brilliance readout system, we measured the center of gravity position of a 25 {mu}m beam at the DORIS III F4 beam line at a rate of 130 Msample/s with narrowband filtering of a few MHz bandwidth. Digitally averaging the signal further provided a spatial resolution {approx}20 nm.

  8. Interaction of ion-acoustic solitons with electron beam in warm plasmas with superthermal electrons

    E-Print Network [OSTI]

    Esfandyari-Kalejahi, A R

    2012-01-01T23:59:59.000Z

    Propagation of ion-acoustic solitary waves (IASWs) is studied using the hydrodynamic equations coupled with the Poisson equation in a warm plasma consisting of adiabatic ions and superthermal (Kappa distributed) electrons in presence of an electron-beam component. In the linear limit, the dispersion relation for ion-acoustic (IA) waves is obtained by linearizing of basic equations. On the other hand, in the nonlinear analysis, an energy-balance like equation involving Sagdeev's pseudo-potential is derived in order to investigate arbitrary amplitude IA solitons. The Mach number range is determined in which, propagation and characteristics of IA solitons are analyzed both parametrically and numerically. The variation of amplitude and width of electrostatic (ES) excitations as a result of superthermality (via) and also the physical parameters (ion temperature, soliton speed, electron-beam density and electron-beam velocity) are examined. A typical interaction between IASWs and the electron-beam in plasma is conf...

  9. Slit disk for modified faraday cup diagnostic for determining power density of electron and ion beams

    DOE Patents [OSTI]

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

    2011-03-08T23:59:59.000Z

    A diagnostic system for characterization of an electron beam or an ion beam includes an electrical conducting disk of refractory material having a circumference, a center, and a Faraday cup assembly positioned to receive the electron beam or ion beam. At least one slit in the disk provides diagnostic characterization of the electron beam or ion beam. The at least one slit is located between the circumference and the center of the disk and includes a radial portion that is in radial alignment with the center and a portion that deviates from radial alignment with the center. The electron beam or ion beam is directed onto the disk and translated to the at least one slit wherein the electron beam or ion beam enters the at least one slit for providing diagnostic characterization of the electron beam or ion beam.

  10. THE n-DISTRIBUTION OF ELECTRONS AND DOUBLE LAYERS IN THE ELECTRON-BEAM-RETURN-CURRENT SYSTEM OF SOLAR FLARES

    SciTech Connect (OSTI)

    Karlicky, Marian, E-mail: karlicky@asu.cas.cz [Astronomical Institute of the Academy of Sciences of the Czech Republic, CZ-25165 Ondrejov (Czech Republic)

    2012-05-01T23:59:59.000Z

    We investigate processes in the electron-beam-return-current system in the impulsive phase of solar flares to answer a question about the formation of the n-electron distribution detected in this phase of solar flares. An evolution of the electron-beam-return-current system with an initial local density depression is studied using a three-dimensional electromagnetic particle-in-cell model. In the system the strong double layer is formed. Its electric field potential increases with the electron beam flux. In this electric field potential, the electrons of background plasma are strongly accelerated and propagate in the return-current direction. The high-energy part of their distribution at the high-potential side of the strong double layer resembles that of the n-distribution. Thus, the detection of the n-distributions, where a form of the high-energy part of the distribution is the most important, can indicate the presence of strong double layers in solar flares. The similarity between processes in solar flare loops and those in the downward current region of the terrestrial aurora, where the double layers were observed by FAST satellite, supports this idea.

  11. Electron beam collector for a microwave power tube

    DOE Patents [OSTI]

    Dandl, Raphael A. (Oak Ridge, TN)

    1980-01-01T23:59:59.000Z

    This invention relates to a cylindrical, electron beam collector that efficiently couples the microwave energy out of a high power microwave source while stopping the attendant electron beam. The interior end walls of the collector are a pair of facing parabolic mirrors and the microwave energy from an input horn is radiated between the two mirrors and reassembled at the entrance to the output waveguide where the transmitted mode is reconstructed. The mode transmission through the collector of the present invention has an efficiency of at least 94%.

  12. Radial electron-beam-breakup transit-time oscillator

    DOE Patents [OSTI]

    Kwan, Thomas J. T. (Los Alamos, NM); Mostrom, Michael A. (Albuquerque, NM)

    1998-01-01T23:59:59.000Z

    A radial electron-beam-breakup transit-time oscillator (RBTO) provides a compact high power microwave generator. The RBTO includes a coaxial vacuum transmission line having an outer conductor and an inner conductor. The inner conductor defines an annular cavity with dimensions effective to support an electromagnetic field in a TEM.sub.00m mode. A radial field emission cathode is formed on the outer conductor for providing an electron beam directed toward the annular cavity electrode. Microwave energy is then extracted from the annular cavity electrode.

  13. Electron beam evaporation for titanium metal matrix composites

    SciTech Connect (OSTI)

    Storer, J. [3M, Mendota Heights, MN (United States)

    1994-12-31T23:59:59.000Z

    3M, in partnership with ARPA, is developing electron beam evaporation as a method for producing titanium metal matrix composites (TMC`s). This paper discusses some of the opportunities presented by these strong and lightweight structural materials but also points out the many challenges which must be met. The excellent mechanical properties of titanium matrix composites have been recognized for quite some time; however use of these materials has been limited by the lack of a commercially viable process to produce them. 3M is removing this logjam in processing technology by using high rate electron beam evaporation technology to manufacture these materials on a significantly large scale.

  14. 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 - Ã?Â?165 MW peak power, power gain of 16 - 20, and pulse duration of 16 - 20 ns at a frequency of 11.43 GHz.

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

    SciTech Connect (OSTI)

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

    2009-10-19T23:59:59.000Z

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

  16. A plasma window for transmission of particle beams and radiation from vacuum to atmosphere for various applications

    SciTech Connect (OSTI)

    Hershcovitch, A. [Brookhaven National Laboratory, Upton, New York11973 (United States)] [Brookhaven National Laboratory, Upton, New York11973 (United States)

    1998-05-01T23:59:59.000Z

    Many industrial and scientific processes like ion material modification, electron beam melting, and welding, as well as generation of synchrotron radiation are performed exclusively in vacuum nowadays, since electron guns, ion guns, their extractors, and accelerators must be kept at a reasonably high vacuum. Consequently, there are numerous limitations, among which are low production rates due to required pumping time, limits on the size of target objects, and degradation of particle beams and radiation through foils or differentially pumped sections. A novel apparatus, which utilized a short plasma arc, was successfully used to provide a vacuum-atmosphere interface as an alternative to differential pumping. Successful transmission of charged particle beams from a vacuum through the plasma to atmosphere was accomplished. Included in the article are a theoretical framework, experimental results, and possible applications for this novel interface. {copyright} {ital 1998 American Institute of Physics.}

  17. 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

  18. Electron beam irradiation of gemstone for color enhancement

    SciTech Connect (OSTI)

    Idris, Sarada; Ghazali, Zulkafli; Hashim, Siti A'iasah; Ahmad, Shamshad; Jusoh, Mohd Suhaimi [Malaysian Nuclear Agency, Bangi, Selangor (Malaysia); School of Chemicals and Material Engineering, NUST Islamabad (Pakistan); Malaysian Nuclear Agency, Bangi, Selangor (Malaysia)

    2012-09-26T23:59:59.000Z

    Numerous treatment of gemstones has been going on for hundreds of years for enhancing color and clarity of gems devoid of these attributes. Whereas previous practices included fraudulent or otherwise processes to achieve the color enhancement, the ionizing radiation has proven to be a reliable and reproducible technique. Three types of irradiation processes include exposure to gamma radiation, electron beam irradiation and the nuclear power plants. Electron Beam Irradiation of Gemstone is a technique in which a gemstone is exposed to highly ionizing radiation electron beam to knock off electrons to generate color centers culminating in introduction of deeper colors. The color centers may be stable or unstable. Below 9MeV, normally no radioactivity is introduced in the exposed gems. A study was conducted at Electron Beam Irradiation Centre (Alurtron) for gemstone color enhancement by using different kind of precious gemstones obtained from Pakistan. The study shows that EB irradiation not only enhances the color but can also improves the clarity of some type of gemstones. The treated stones included kunzite, tourmaline, topaz, quartz, aquamarine and cultured pearls. Doses ranging from 25 kGy to 200 KGy were employed to assess the influence of doses on color and clarity and to select the optimum doses. The samples used included both the natural and the faceted gemstones. It is concluded that significant revenue generation is associated with the enhancement of the color in clarity of gemstones which are available at very cheap price in the world market.

  19. 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.

  20. System tests of the LHCb RICH detectors in a charged particle beam

    E-Print Network [OSTI]

    Skottowe, Hugh

    2009-01-01T23:59:59.000Z

    The RICH detectors of the LHCb experiment will provide efficient particle identification over the momentum range 1-100 GeV=c. Results are presented from a beam test of the LHCb RICH system using final production pixel Hybrid Photon Detectors, the final readout electronics and an adapted version of LHCb RICH reconstruction software. Measurements of the photon yields and Cherenkov angle resolutions for both nitrogen and C4F10 radiators agree well with full simulations. The quality of the data and the results obtained demonstrate that all aspects meet the stringent physics requirements of the experiment are now ready for first data.

  1. An experience of electron beam (EB) irradiated gemstones in Malaysian nuclear agency

    SciTech Connect (OSTI)

    Idris, Sarada, E-mail: sarada@nuclearmalaysia.gov.my; Hairaldin, Siti Zulaiha, E-mail: sarada@nuclearmalaysia.gov.my; Tajau, Rida, E-mail: sarada@nuclearmalaysia.gov.my; Karim, Jamilah, E-mail: sarada@nuclearmalaysia.gov.my; Jusoh, Suhaimi, E-mail: sarada@nuclearmalaysia.gov.my; Ghazali, Zulkafli, E-mail: sarada@nuclearmalaysia.gov.my [Malaysian Nuclear Agency, Bangi, Selangor (Malaysia); Ahmad, Shamshad [School of Chemicals and Material Engineering, NUST Islamabad (Pakistan)

    2014-02-12T23:59:59.000Z

    In Nuclear Malaysia, a study on gemstone irradiation using beta particle is conducted. The purpose of the study is to evaluate the gemstone colour enhancement by using different kind of precious and non-precious gemstones. By using irradiation technique, selected gemstones are exposed to highly ionizing radiation electron beam to knock off electrons to generate colour centres culminating in the introduction of deeper colours. The colour centres may be stable or unstable depending on the nature of colour centre produced. The colour change of irradiated stones were measured by HunterLab colour measurement. At 50 kGy, Topaz shows changes colour from colourless to golden. Meanwhile pearl shows changes from pale colour to grey. Kunzite and amethyst shows colour changes from colorless to green and pale colour to purple. Gamma survey meter measurement confirmed that irradiation treatment with 3 MeV electron beam machine does not render any activation that activate the gems to become radioactive.

  2. Electron beam melting capability at Cabot Performance Materials

    SciTech Connect (OSTI)

    Fisher, J.G. [Cabot Performance Materials, Boyertown, PA (United States)

    1995-12-31T23:59:59.000Z

    Cabot Performance Materials is a manufacturer of selected performance metals from ores to finished powder and mill shapes. CPM has been a world leader for over 40 years in the technology and production of tantalum and niobium for the electronics, aerospace, defense, and chemical processing industries. This paper presents a historical overview of their electron beam furnaces culminating with the successful installation of a second 1200 KW furnace.

  3. Electron Beam Welding of a Depleted Uranium Alloy to Niobium Using a Calibrated Electron Beam Power Density Distribution

    SciTech Connect (OSTI)

    Elmer, J.W.; Teruya, A.T.; Terrill, P.E.

    2000-08-21T23:59:59.000Z

    Electron beam test welds were made joining flat plates of commercially pure niobium to a uranium-6wt%Nb (binary) alloy. The welding parameters and joint design were specifically developed to minimize mixing of the niobium with the U-6%Nb alloy. A Modified Faraday Cup (MFC) technique using computer-assisted tomography was employed to determine the precise power distribution of the electron beam so that the welding parameters could be directly transferred to other welding machines and/or to other facilities.

  4. Reversible electron beam heating for suppression of microbunching instabilities at free-electron lasers

    E-Print Network [OSTI]

    Behrens, Christopher; Xiang, Dao

    2011-01-01T23:59:59.000Z

    The presence of microbunching instabilities due to the compression of high-brightness electron beams at existing and future X-ray free-electron lasers (FELs) results in restrictions on the attainable lasing performance and renders beam imaging with optical transition radiation impossible. The instability can be suppressed by introducing additional energy spread, i.e., "heating" the electron beam, as demonstrated by the successful operation of the laser heater system at the Linac Coherent Light Source. The increased energy spread is typically tolerable for self-amplified spontaneous emission FELs but limits the effectiveness of advanced FEL schemes such as seeding. In this paper, we present a reversible electron beam heating system based on two transverse deflecting radio-frequency structures (TDSs) in front and behind a magnetic bunch compressor chicane. The additional energy spread will be introduced in the first TDS, which suppresses the microbunching instability, and then will be eliminated in the second T...

  5. Simulation of multicomponent evaporation in electron beam melting and refining

    SciTech Connect (OSTI)

    Powell, A.; Szekely, J. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Van Den Avyle, J.; Damkroger, B. [Sandia National Labs., Albuquerque, NM (United States)

    1996-06-01T23:59:59.000Z

    Experimental results and a mathematical model are presented to describe differential evaporation rates in electron beam melting of titanium alloys containing aluminum and vanadium. Experiments characterized the evaporation rate of commercially pure titanium, and vapor composition over titanium with up to 6% Al and 4.5% V content as a function of beam power, scan frequency and background pressure. The model is made up of a steady-state heat and mass transport model of a melting hearth and a model of transient thermal and flow behavior near the surface. Activity coefficients for aluminum and vanadium in titanium are roughly estimated by fitting model parameters to experimental results. Based on the ability to vary evaporation rate by 10-15% using scan frequency alone, we discuss the possibility of on-line composition control by means of intelligent manipulation of the electron beam.

  6. The geometric phase and the geometrodynamics of relativistic electron vortex beams

    E-Print Network [OSTI]

    Pratul Bandyopadhyay; Banasri Basu; Debashree Chowdhury

    2013-11-28T23:59:59.000Z

    We have studied here the geometrodynamics of relativistic electron vortex beams from the perspective of the geometric phase associated with the scalar electron encircling the vortex line. It is pointed out that the electron vortex beam carrying orbital angular momentum is a natural consequence of the skyrmion model of a fermion. This follows from the quantization procedure of a fermion in the framework of Nelson's stochastic mechanics when a direction vector (vortex line) is introduced to depict the spin degrees of freedom. In this formalism a fermion is depicted as a scalar particle encircling a vortex line. It is here shown that when the Berry phase acquired by the scalar electron encircling the vortex line involves quantized Dirac monopole we have paraxial (non-paraxial) beam when the vortex line is parallel (orthogonal) to the wavefront propagation direction. Non-paraxial beams incorporate spin-orbit interaction. When the vortex line is tilted with respect to the propagation direction the Berry phase involves non-quantized monopole. The temporal variation of the direction of the tilted vortices is studied here taking into account the renormalization group flow of the monopole charge and it is predicted that this gives rise to spin Hall effect.

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

    SciTech Connect (OSTI)

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

    2014-07-15T23:59:59.000Z

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

  8. Risk Management Plan Electron Beam Ion Source Project

    E-Print Network [OSTI]

    Risk Management Plan for the Electron Beam Ion Source Project (EBIS) Project # 06-SC-002. There are three specific areas of risk that can be controlled and managed by the EBIS Project team and these are and operations. The BNL ISM clearly indicates that risk management is everybody's business and will be factored

  9. Development of a chemical dosimeter for electron beam food irradiation

    E-Print Network [OSTI]

    Rivadeneira, Ramiro Geovanny

    2006-08-16T23:59:59.000Z

    uniform irradiation treatment on apple-phantoms (a complex shaped target) and GAFCHROMIC® HD-810 films using electron beams from (1) a 2 MeV Van de Graaff (VDG) accelerator, (2) a 10 MeV Linear Accelerator (LINAC), and (3) X-rays from a 5 MeV LINAC...

  10. Electron beam melting and casting of zirconium and titanium alloys

    SciTech Connect (OSTI)

    Arzhakova, V.M.; Popov, E.I. [A.A. Bochvar All Union Scientific and Research Institute of Inorganic Materials, Moscow (Russian Federation); Dubrovski, V.A.; Frolov, V.I. [PO ChMZ, Glazov (Russian Federation); Ladohin, S.V.; Levitsky, N.I.; Chernyavsky, V.B. [Scientific and Research Institute of Casting, Kiev (Ukraine)

    1994-12-31T23:59:59.000Z

    The results of electron beam melting (EBM) and casting Zirconium and Titanium alloys are discussed. The data on different schedules used for EBM of this metals as well as equipment for crucible melting and special equipment for casting are described. The results of production of Zirconium and Titanium alloy mold castings for various purposes are presented.

  11. Electron Beam--21st Century Food Technology

    E-Print Network [OSTI]

    Vestal, Andy

    2003-03-07T23:59:59.000Z

    and spoil food, sometimes without changing the food's taste, smell, or appearance. Cesium 137, Cobalt 60: Metals that are produced by nuclear reaction and give off ionizing radiation as gamma rays. Chemical Sprout Inhibitors: Certain chemicals being used... flipping is not required and processing can be accomplished in seconds. In the X-Ray Mode, electrons are accelerated to near the speed of light using microwaves into a dense metal which emits X-Rays that pass through the product breaking the DNA chain...

  12. 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.

  13. Energy-range relation and mean energy variation in therapeutic particle beams

    SciTech Connect (OSTI)

    Kempe, Johanna; Brahme, Anders [Division of Medical Radiation Physics, Department of Oncology-Pathology, Karolinska Institutet and Stockholm University, Box 260, SE-171 76 Stockholm (Sweden)

    2008-01-15T23:59:59.000Z

    Analytical expressions for the mean energy and range of therapeutic light ion beams and low- and high-energy electrons have been derived, based on the energy dependence of their respective stopping powers. The new mean energy and range relations are power-law expressions relevant for light ion radiation therapy, and are based on measured practical ranges or known tabulated stopping powers and ranges for the relevant incident particle energies. A practical extrapolated range, R{sub p}, for light ions was defined, similar to that of electrons, which is very closely related to the extrapolated range of the primary ions. A universal energy-range relation for light ions and electrons that is valid for all material mixtures and compounds has been developed. The new relation can be expressed in terms of the range for protons and alpha particles, and is found to agree closely with experimental data in low atomic number media and when the difference in the mean ionization energy is low. The variation of the mean energy with depth and the new energy-range relation are useful for accurate stopping power and mass scattering power calculations, as well as for general particle transport and dosimetry applications.

  14. Method and split cavity oscillator/modulator to generate pulsed particle beams and electromagnetic fields

    DOE Patents [OSTI]

    Clark, M.C.; Coleman, P.D.; Marder, B.M.

    1993-08-10T23:59:59.000Z

    A compact device called the split cavity modulator whose self-generated oscillating electromagnetic field converts a steady particle beam into a modulated particle beam. The particle beam experiences both signs of the oscillating electric field during the transit through the split cavity modulator. The modulated particle beam can then be used to generate microwaves at that frequency and through the use of extractors, high efficiency extraction of microwave power is enabled. The modulated beam and the microwave frequency can be varied by the placement of resistive wires at nodes of oscillation within the cavity. The short beam travel length through the cavity permit higher currents because both space charge and pinching limitations are reduced. The need for an applied magnetic field to control the beam has been eliminated.

  15. Method and split cavity oscillator/modulator to generate pulsed particle beams and electromagnetic fields

    DOE Patents [OSTI]

    Clark, M. Collins (Albuquerque, NM); Coleman, P. Dale (Albuquerque, NM); Marder, Barry M. (Albuquerque, NM)

    1993-01-01T23:59:59.000Z

    A compact device called the split cavity modulator whose self-generated oscillating electromagnetic field converts a steady particle beam into a modulated particle beam. The particle beam experiences both signs of the oscillating electric field during the transit through the split cavity modulator. The modulated particle beam can then be used to generate microwaves at that frequency and through the use of extractors, high efficiency extraction of microwave power is enabled. The modulated beam and the microwave frequency can be varied by the placement of resistive wires at nodes of oscillation within the cavity. The short beam travel length through the cavity permit higher currents because both space charge and pinching limitations are reduced. The need for an applied magnetic field to control the beam has been eliminated.

  16. annular beam free-electron: Topics by E-print Network

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

    and X-ray regions is predicted. KeywordsFree-electron laser, Higher energy beam, Lower energy beam, Two-beam M. Zahedian; B. Maraghechi; M. H. Rouhani 6 Analytic model of...

  17. Upgrade of laser and electron beam welding database

    E-Print Network [OSTI]

    Furman, Magdalena

    2014-01-01T23:59:59.000Z

    The main purpose of this project was to fix existing issues and update the existing database holding parameters of laser-beam and electron-beam welding machines. Moreover, the database had to be extended to hold the data for the new machines that arrived recently at the workshop. As a solution - the database had to be migrated to Oracle framework, the new user interface (using APEX) had to be designed and implemented with the integration with the CERN web services (EDMS, Phonebook, JMT, CDD and EDH).

  18. Method of automatic measurement and focus of an electron beam and apparatus therefore

    DOE Patents [OSTI]

    Giedt, W.H.; Campiotti, R.

    1996-01-09T23:59:59.000Z

    An electron beam focusing system, including a plural slit-type Faraday beam trap, for measuring the diameter of an electron beam and automatically focusing the beam for welding is disclosed. Beam size is determined from profiles of the current measured as the beam is swept over at least two narrow slits of the beam trap. An automated procedure changes the focus coil current until the focal point location is just below a workpiece surface. A parabolic equation is fitted to the calculated beam sizes from which optimal focus coil current and optimal beam diameter are determined. 12 figs.

  19. Numerical Study of Coulomb Scattering Effects on Electron Beam from a Nano-Tip

    E-Print Network [OSTI]

    2008-01-01T23:59:59.000Z

    electron beam emitted from a nano- tip. We found that theon Electron Beam from a Nano-Tip ? J. Qiang † , J. Corlett,Switzerland ‡ Abstract Nano-tips with high acceleration

  20. Simulation of Electron-Beam Irradiation of Skin Tissue Model

    SciTech Connect (OSTI)

    Miller, John H.; Suleiman, Atef; Chrisler, William B.; Sowa, Marianne B.

    2011-01-03T23:59:59.000Z

    Monte Carlo simulation of electrons stopping in liquid water was used to model the penetration and dose distribution of electron beams incident on the full-thickness EpiDermTM skin model (MatTek, Ashland, VA). This 3D tissue model has a fully developed basement membrane separating an epidermal layer of keratinocytes in various stages of differentiation from a dermal layer of fibroblast embedded in collagen. The simulations were motivated by a desire to selectively expose the epidermal layer to low linear-energy-transfer (LET) radiation in the presence of a non-irradiated dermal layer. Using the variable energy electron microbeam at the Pacific Northwest National Laboratory (PNNL) as a model of device characteristics and irradiation geometry, we find that at the highest beam energy available (90 keV), the estimated 90th percentile of penetration remains in the epidermal layer. To investigate the depth-dose distribution, we calculated lineal energy spectra for 10um thick layers near the 10th, 50th, and 90th percentile of penetration by the 90 keV electron beam. Biphasic spectra showed an increasing component of "stoppers" with increasing depth. Despite changes in the lineal energy spectra, the main effect on dose deposition with increasing depth is the screening effect of tissue above the layer of interest.

  1. Electron Beam Charge Diagnostics for Laser Plasma Accelerators

    SciTech Connect (OSTI)

    Nakamura, Kei; Gonsalves, Anthony; Lin, Chen; Smith, Alan; Rodgers, David; Donahue, Rich; Byrne, Warren; Leemans, Wim

    2011-06-27T23:59:59.000Z

    A comprehensive study of charge diagnostics is conducted to verify their validity for measuring electron beams produced by laser plasma accelerators (LPAs). First, a scintillating screen (Lanex) was extensively studied using subnanosecond electron beams from the Advanced Light Source booster synchrotron, at the Lawrence Berkeley National Laboratory. The Lanex was cross calibrated with an integrating current transformer (ICT) for up to the electron energy of 1.5 GeV, and the linear response of the screen was confirmed for charge density and intensity up to 160 pC/mm{sup 2} and 0.4 pC/(ps mm{sup 2}), respectively. After the radio-frequency accelerator based cross calibration, a series of measurements was conducted using electron beams from an LPA. Cross calibrations were carried out using an activation-based measurement that is immune to electromagnetic pulse noise, ICT, and Lanex. The diagnostics agreed within {+-}8%, showing that they all can provide accurate charge measurements for LPAs.

  2. Langmuir wave-packet generation from an electron beam propagating in the inhomogeneous solar wind

    SciTech Connect (OSTI)

    Zaslavsky, A.; Maksimovic, M. [LESIA, 5 Place Jules Janssen, 92195 Meudon (France); Volokitin, A. S. [IZMIRAN, Troitsk, Moscow Region (Russian Federation); Krasnoselskikh, V. V. [LPCEE, CNRS Orleans (France); Bale, S. D. [SSL, University of California, Berkerley (United States)

    2010-03-25T23:59:59.000Z

    Recent in-situ observations by the TDS instrument equipping the STEREO spacecraft revealed that large amplitude spatially localized Langmuir waves are frequent in the solar wind, and correlated with the presence of suprathermal electron beams during type III events or close to the electron foreshock. We briefly present the new theoretical model used to perform the study of these localized electrostatic waves, and show first results of simulations of the destabilization of Langmuir waves by a beam propagating in the inhomogeneous solar wind. The main results are that the destabilized waves are mainly focalized near the minima of the density profiles, and that the nonlinear interaction of the waves with the resonant particles enhances this focalization compared to a situation in which the only propagation effects are taken into account.

  3. Ultra low-K shrinkage behavior when under electron beam in a scanning electron microscope

    SciTech Connect (OSTI)

    Lorut, F.; Imbert, G. [ST Microelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex (France)] [ST Microelectronics, 850 rue Jean Monnet, 38926 Crolles Cedex (France); Roggero, A. [Centre National d'Etudes Spatiales, 18 Avenue Edouard Belin, 31400 Toulouse (France)] [Centre National d'Etudes Spatiales, 18 Avenue Edouard Belin, 31400 Toulouse (France)

    2013-08-28T23:59:59.000Z

    In this paper, we investigate the tendency of porous low-K dielectrics (also named Ultra Low-K, ULK) behavior to shrink when exposed to the electron beam of a scanning electron microscope. Various experimental electron beam conditions have been used for irradiating ULK thin films, and the resulting shrinkage has been measured through use of an atomic force microscope tool. We report the shrinkage to be a fast, cumulative, and dose dependent effect. Correlation of the shrinkage with incident electron beam energy loss has also been evidenced. The chemical modification of the ULK films within the interaction volume has been demonstrated, with a densification of the layer and a loss of carbon and hydrogen elements being observed.

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

    E-Print Network [OSTI]

    Bakeman, M.S.

    2011-01-01T23:59:59.000Z

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

  5. Electron beam transport in gas-loaded free-electron lasers

    SciTech Connect (OSTI)

    Yariv, S.; Friedland, L. (Center for Plasma Physics, Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem, Israel (IL))

    1990-12-01T23:59:59.000Z

    The effects of the presence of helical wiggler and axial guide magnetic fields on the quality of the electron beam in a gas-loaded free-electron laser are investigated. The electron velocity space diffusion theory in the free-electron laser is developed and tested in Monte Carlo simulations. The theory is applied in estimating the collisional limitations on the interaction length of the laser. It is shown that two competing effects related to collisions cause the gain loss in gas-loaded free-electron lasers, i.e., (a) the growing phase mismatch between the electrons and the wave and (b) the destruction of the coherent transverse helical beam motion. The second effect dominates in the absence of the guide field, provided the wiggler field strength is sufficiently small.

  6. ELECTRON BEAM ION SOURCE PREINJECTOR PROJECT (EBIS) CONCEPTUAL DESIGN REPORT.

    SciTech Connect (OSTI)

    ALESSI, J.; BARTON, D.; BEEBE, E.; GASSNER, D.; ET AL.

    2005-02-28T23:59:59.000Z

    This report describes a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC) based on a high charge state Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ) accelerator, and a short Linac. The highly successful development of an EBIS at BNL now makes it possible to replace the present pre-injector that is based on an electrostatic Tandem with a reliable, low maintenance Linac-based pre-injector. Linac-based pre-injectors are presently used at most accelerator and collider facilities with the exception of RHIC, where the required gold beam intensities could only be met with a Tandem until the recent EBIS development. EBIS produces high charge state ions directly, eliminating the need for the two stripping foils presently used with the Tandem. Unstable stripping efficiencies of these foils are a significant source of luminosity degradation in RHIC. The high reliability and flexibility of the new Linac-based pre-injector will lead to increased integrated luminosity at RHIC and is an essential component for the long-term success of the RHIC facility. This new pre-injector, based on an EBIS, also has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium beams and, as part of a future upgrade, might also be used to produce polarized {sup 3}He beams. These capabilities will be critical to the future luminosity upgrades and electron-ion collisions in RHIC. The new RFQ and Linac that are used to accelerate beams from the EBIS to an energy sufficient for injection into the Booster are both very similar to existing devices already in operation at other facilities. Injection into the Booster will occur at the same location as the existing injection from the Tandem.

  7. Proceedings of the conference on electron beam melting and refining - state of the art 1996

    SciTech Connect (OSTI)

    Bakish, R. [ed.

    1996-12-31T23:59:59.000Z

    This conference proceedings summarizes state-of-the-art work in the field of electron-beam melting and refining, as presented at the 1996 conference. Papers are grouped as follows: invited papers; tutorial papers; electron beam melting related fundamentals; electron beam evaporation papers; and miscellaneous papers. Separate abstracts have been submitted to the energy database for some contributions to this proceedings.

  8. GeV electron beams from a cm-scale accelerator

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    radiation facilities and free electron lasers, and as modules for high-energy particle physics. Radiofrequency-

  9. Nanowire growth by an electron beam induced massive phase transformation

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

    Sood, Shantanu; Kisslinger, Kim; Gouma, Perena

    2014-12-01T23:59:59.000Z

    Tungsten trioxide nanowires of a high aspect ratio have been synthesized in-situ in a TEM under an electron beam of current density 14A/cm² due to a massive polymorphic reaction. Sol-gel processed pseudocubic phase nanocrystals of tungsten trioxide were seen to rapidly transform to one dimensional monoclinic phase configurations, and this reaction was independent of the substrate on which the material was deposited. The mechanism of the self-catalyzed polymorphic transition and accompanying radical shape change is a typical characteristic of metastable to stable phase transformations in nanostructured polymorphic metal oxides. A heuristic model is used to confirm the metastable to stablemore »growth mechanism. The findings are important to the control electron beam deposition of nanowires for functional applications starting from colloidal precursors.« less

  10. 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.

  11. Analysis of Shot Noise Suppression for Electron Beams

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

    Ratner, Daniel; Huang, Zhirong; Stupakov, Gennady

    2015-02-02T23:59:59.000Z

    Shot noise can affect the performance of free-electron lasers (FELs) by driving instabilities (e.g., the microbunching instability) or by competing with seeded density modulations. Recent papers have proposed suppressing shot noise to enhance FEL performance. In this paper we use a onedimensional (1D) model to calculate the noise amplification from an energy modulation (e.g., electron interactions from space charge or undulator radiation) followed by a dispersive section. We show that, for a broad class of interactions, selecting the correct dispersive strength suppresses shot noise across a wide range of frequencies. The final noise level depends on the beam’s energy spread and the properties of the interaction potential. We confirm and illustrate our analytical results with 1D simulations.

  12. Nanowire growth by an electron beam induced massive phase transformation

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

    Sood, Shantanu [State Univ., of New York, Stony Brook, NY (United States); Kisslinger, Kim [Brookhaven National Lab. (BNL), Upton, NY (United States); Gouma, Perena [State Univ., of New York, Stony Brook, NY (United States)

    2014-12-01T23:59:59.000Z

    Tungsten trioxide nanowires of a high aspect ratio have been synthesized in-situ in a TEM under an electron beam of current density 14A/cm² due to a massive polymorphic reaction. Sol-gel processed pseudocubic phase nanocrystals of tungsten trioxide were seen to rapidly transform to one dimensional monoclinic phase configurations, and this reaction was independent of the substrate on which the material was deposited. The mechanism of the self-catalyzed polymorphic transition and accompanying radical shape change is a typical characteristic of metastable to stable phase transformations in nanostructured polymorphic metal oxides. A heuristic model is used to confirm the metastable to stable growth mechanism. The findings are important to the control electron beam deposition of nanowires for functional applications starting from colloidal precursors.

  13. Energy exchange between a laser beam and charged particles using inverse transition radiation and method for its use

    DOE Patents [OSTI]

    Kimura, Wayne D. (Bellevue, WA); Romea, Richard D. (Seattle, WA); Steinhauer, Loren C. (Bothell, WA)

    1998-01-01T23:59:59.000Z

    A method and apparatus for exchanging energy between relativistic charged particles and laser radiation using inverse diffraction radiation or inverse transition radiation. The beam of laser light is directed onto a particle beam by means of two optical elements which have apertures or foils through which the particle beam passes. The two apertures or foils are spaced by a predetermined distance of separation and the angle of interaction between the laser beam and the particle beam is set at a specific angle. The separation and angle are a function of the wavelength of the laser light and the relativistic energy of the particle beam. In a diffraction embodiment, the interaction between the laser and particle beams is determined by the diffraction effect due to the apertures in the optical elements. In a transition embodiment, the interaction between the laser and particle beams is determined by the transition effect due to pieces of foil placed in the particle beam path.

  14. Use of incomplete energy recovery for the energy compression of large energy spread charged particle beams

    DOE Patents [OSTI]

    Douglas, David R. (Newport News, VA); Benson, Stephen V. (Yorktown, VA)

    2007-01-23T23:59:59.000Z

    A method of energy recovery for RF-base linear charged particle accelerators that allows energy recovery without large relative momentum spread of the particle beam involving first accelerating a waveform particle beam having a crest and a centroid with an injection energy E.sub.o with the centroid of the particle beam at a phase offset f.sub.o from the crest of the accelerating waveform to an energy E.sub.full and then recovering the beam energy centroid a phase f.sub.o+Df relative to the crest of the waveform particle beam such that (E.sub.full-E.sub.o)(1+cos(f.sub.o+Df))>dE/2 wherein dE=the full energy spread, dE/2=the full energy half spread and Df=the wave form phase distance.

  15. Characterization of electron beam melted uranium - 6% niobium ingots

    SciTech Connect (OSTI)

    McKoon, R.H.

    1997-10-31T23:59:59.000Z

    A study was undertaken at Lawrence Livermore National Laboratory to characterize uranium, 6{percent} niobium ingots produced via electron beam melting,hearth refining and continuous casting and to compare this material with conventional VIM/skull melt /VAR material. Samples of both the ingot and feed material were analyzed for niobium, trace metallic elements, carbon, oxygen and nitrogen. Ingot samples were also inspected metallographically and via microprobe analysis.

  16. Electron-beam-induced growth of silicon multibranched nanostructures

    SciTech Connect (OSTI)

    Fonseca, Luis F.; Resto, Oscar; Sola, Francisco [Department of Physics, University of Puerto Rico, P. O. Box 23343, San Juan, 00931-3343 (Puerto Rico)

    2005-09-12T23:59:59.000Z

    Although successful nanobranching has been demonstrated for some materials using a variety of methods, the controlled fabrication of multibranched nanostructures of silicon is an important challenge faced by nanotechnologist; because it is crucial for the assembly of electronic interconnects at the atomic scale. Here, we report an electron-beam-induced approach that enables to grow silicon nanobranched structures at specific locations and to control the growth process at the nanoscale level. We further present a detailed in situ imaging of the growth dynamics and explain the results by a qualitative model based on local heating and charge concentration processes.

  17. Laser-driven relativistic electron beam interaction with solid dielectric

    SciTech Connect (OSTI)

    Sarkisov, G. S.; Ivanov, V. V.; Leblanc, P.; Sentoku, Y.; Yates, K.; Wiewior, P.; Chalyy, O.; Astanovitskiy, A.; Bychenkov, V. Yu.; Jobe, D.; Spielman, R. B. [Raytheon Ktech, 1300 Eubank Blvd, Albuquerque, NM, 87123 (United States); Department of Physics, University of Nevada Reno, 5625 Fox Ave, Reno, NV, 89506 (United States); P.N. Lebedev Physics Institute, RAS, 53 Leninski Prospect, Moscow, 119991 (Russian Federation); Raytheon Ktech, 1300 Eubank Blvd, Albuquerque, NM, 87123 (Russian Federation)

    2012-07-30T23:59:59.000Z

    The multi-frames shadowgraphy, interferometry and polarimetry diagnostics with sub-ps time resolution were used for an investigation of ionization wave dynamics inside a glass target induced by laser-driven relativistic electron beam. Experiments were done using the 50 TW Leopard laser at the UNR. For a laser flux of {approx}2 Multiplication-Sign 10{sup 18}W/cm{sup 2} a hemispherical ionization wave propagates at c/3. The maximum of the electron density inside the glass target is {approx}2 Multiplication-Sign 10{sup 19}cm{sup -3}. Magnetic and electric fields are less than {approx}15 kG and {approx}1 MV/cm, respectively. The electron temperature has a maximum of {approx}0.5 eV. 2D interference phase shift shows the 'fountain effect' of electron beam. The very low ionization inside glass target {approx}0.1% suggests a fast recombination at the sub-ps time scale. 2D PIC-simulations demonstrate radial spreading of fast electrons by self-consistent electrostatic fields.

  18. Method and apparatus for measuring properties of particle beams using thermo-resistive material properties

    DOE Patents [OSTI]

    Degtiarenko, Pavel V. (Williamsburg, VA); Dotson, Danny Wayne (Gloucester, VA)

    2007-10-09T23:59:59.000Z

    A beam position detector for measuring the properties of a charged particle beam, including the beam's position, size, shape, and intensity. One or more absorbers are constructed of thermo-resistive material and positioned to intercept and absorb a portion of the incoming beam power, thereby causing local heating of each absorber. The local temperature increase distribution across the absorber, or the distribution between different absorbers, will depend on the intensity, size, and position of the beam. The absorbers are constructed of a material having a strong dependence of electrical resistivity on temperature. The beam position detector has no moving parts in the vicinity of the beam and is especially suited to beam areas having high ionizing radiation dose rates or poor beam quality, including beams dispersed in the transverse direction and in their time radio frequency structure.

  19. Method and apparatus for measuring the momentum, energy, power, and power density profile of intense particle beams

    DOE Patents [OSTI]

    Gammel, George M. (Merrick, NY); Kugel, Henry W. (Somerset, NJ)

    1992-10-06T23:59:59.000Z

    A method and apparatus for determining the power, momentum, energy, and power density profile of high momentum mass flow. Small probe projectiles of appropriate size, shape and composition are propelled through an intense particle beam at equal intervals along an axis perpendicular to the beam direction. Probe projectiles are deflected by collisions with beam particles. The net beam-induced deflection of each projectile is measured after it passes through the intense particle beam into an array of suitable detectors.

  20. ELECTRON BEAM ION SOURCE PREINJECTOR PROJECT (EBIS) CONCEPTUAL DESIGN REPORT.

    SciTech Connect (OSTI)

    ALESSI, J.; BARTON, D.; BEEBE, E.; GASSNER, D.; GRANDINETTI, R.; HSEUH, H.; JAVIDFAR, A.; KPONOU, A.; LAMBIASE, R.; LESSARD, E.; LOCKEY, R.; LODESTRO, V.; MAPES, M.; MIRABELLA, D.; NEHRING, T.; OERTER, B.; PENDZICK, A.; PIKIN, A.; RAPARIA, D.; RITTER, J.; ROSER, T.; RUSSO, T.; SNYDSTRUP, L.; WILINSKI, M.; ZALTSMAN, A.; ZHANG, S.

    2005-09-01T23:59:59.000Z

    This report describes a new heavy ion pre-injector for the Relativistic Heavy Ion Collider (RHIC) based on a high charge state Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ) accelerator, and a short Linear accelerator (Linac). The highly successful development of an EBIS at Brookhaven National Laboratory (BNL) now makes it possible to replace the present pre-injector that is based on an electrostatic Tandem with a reliable, low maintenance Linac-based pre-injector. Linac-based preinjectors are presently used at most accelerator and collider facilities with the exception of RHIC, where the required gold beam intensities could only be met with a Tandem until the recent EBIS development. EBIS produces high charge state ions directly, eliminating the need for the two stripping foils presently used with the Tandem. Unstable stripping efficiencies of these foils are a significant source of luminosity degradation in RHIC. The high reliability and flexibility of the new Linac-based pre-injector will lead to increased integrated luminosity at RHIC and is an essential component for the long-term success of the RHIC facility. This new pre-injector, based on an EBIS, also has the potential for significant future intensity increases and can produce heavy ion beams of all species including uranium beams and, as part of a future upgrade, might also be used to produce polarized {sup 3}He beams. These capabilities will be critical to the future luminosity upgrades and electron-ion collisions in RHIC. The proposed pre-injector system would also provide for a major enhancement in capability for the NASA Space Radiation Laboratory (NSRL), which utilizes heavy-ion beams from the RHIC complex. EBIS would allow for the acceleration of all important ion species for the NASA radiobiology program, such as, helium, argon, and neon which are unavailable with the present Tandem injector. In addition, the new system would allow for very rapid switching of ion species for NSRL experiments, reducing delays due to the interference with RHIC injection operations, and allowing enhanced mixed field radiation studies. The new RFQ and Linac that are used to accelerate beams from the EBIS to an energy sufficient for injection into the Booster are both very similar to existing devices already in operation at other facilities. Injection into the Booster will occur at the same location as the existing injection from the Tandem.

  1. A system for the tomographic determination of the power distribution in electron beams

    SciTech Connect (OSTI)

    Teruya, A.; Elmer, J.; O`Brien, D.

    1991-12-06T23:59:59.000Z

    A computer tomographic technique was developed to measure the current density distribution in electron beams. This technique uses electron-beam profile data acquired from a modified Faraday cup to create an image of the current density in high power beams. The beam profile data is acquired by sweeping the beam across a narrow slit. The beam current, integrated along the axis of the slit, is captured by a Faraday cup and its waveform is recorded by a digitizing storage oscilloscope. The slit is repeatedly rotated and beam current waveforms are recorded at regularly spaced angles. A 2-dimensional image of the current density distribution in the beam is reconstructed from this information, providing quantitative information about the beam focus and alignment. This paper discusses the techniques used to record beam profiles, discusses the computer tomographic reconstruction of beams, and presents an example of how this method can be used to control beam focus in an unbiased way. 7 refs.

  2. Transient beam losses in the LHC injection kickers from micron scale dust particles

    E-Print Network [OSTI]

    Goddard, B; Baer, T; Barnes, M J; Cerutti, F; Ferrari, A; Garrel, N; Gerardin, A; Guinchard, M; Lechner, A; Masi, A; Mertens, V; Morón Ballester, R; Redaelli, S; Uythoven, J; Vlachoudis, V; Zimmermann, F

    2012-01-01T23:59:59.000Z

    Transient beam losses on a time scale of a few ms have been observed in the LHC injection kickers, occurring mainly shortly after beam injection with a strong correlation in time to the kicker pulsing. The beam losses, which have at times affected LHC availability, are attributed to micron scale ceramic dust particles detached from the alumina beam pipe and accelerated into the beam. The beam related observations are described, together with laboratory measurements of beam pipe contamination and kicker vibration, simulations of electric field in the beam pipe and the basic dynamic model. Energy deposition simulations modelling the beam losses are presented and compared to measurement. Extrapolations to future LHC operation at higher intensities and energies are made, and prospects for mitigation are discussed.

  3. Initial commissioning results with the NSCL Electron Beam Ion Trap

    SciTech Connect (OSTI)

    Schwarz, S.; Kittimanapun, K.; Lapierre, A.; Leitner, D.; Ottarson, J.; Portillo, M. [National Superconducting Cyclotron Laboratory, NSCL, Michigan State University, East Lansing, Michigan 48824 (United States); Bollen, G. [National Superconducting Cyclotron Laboratory, NSCL, Michigan State University, East Lansing, Michigan 48824 (United States); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); Lopez-Urrutia, J. R. Crespo [Max-Planck Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Kester, O. [GSI Helmholtzzentrum fuer Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany)

    2012-02-15T23:59:59.000Z

    The ReA reaccelerator is being added to the National Superconducting Cyclotron Laboratory (NSCL) fragmentation facility in order to provide exotic rare-isotope beams, not available at the Isotope Separation On-Line facilities, in the several-MeV/u energy range. The first stage of the NSCL reaccelerator complex, consisting of an EBIT charge breeder, a room-temperature radiofrequency quadrupole (RFQ) accelerator, and superconducting linear accelerator modules, has been completed and is being put into operation. Commissioning of the EBIT has started by extracting charge-bred residual gas ions, ions created from a Ne gas jet directed across the EBIT's electron beam and ions captured from an external test ion source. Charge-bred ions from the Ne gas jet have been extracted as a pulse and accelerated through the RFQ and the two cryomodules.

  4. Cold electron beams from cryo-cooled, alkali antimonide photocathodes

    E-Print Network [OSTI]

    Cultrera, Luca; Lee, Hyeri; Liu, Xianghong; Bazarov, Ivan

    2015-01-01T23:59:59.000Z

    In this letter we report on the generation of cold electron beams using a Cs3Sb photocathode grown by co-deposition of Sb and Cs. By cooling the photocathode to 90 K we demonstrate a significant reduction in the mean transverse energy validating the long standing speculation that the lattice temperature contribution limits the mean transverse energy or thermal emittance near the photoemission threshold, opening new frontiers in generating ultra-bright beams. At 90 K, we achieve a record low thermal emittance of 0.2 $\\mu$m (rms) per mm of laser spot diameter from an ultrafast (sub-picosecond) photocathode with quantum efficiency greater than $7\\times 10^{-5}$ using a visible laser wavelength of 690 nm.

  5. Issues for Bringing Electron Beam Irradiators On-Line

    SciTech Connect (OSTI)

    Kaye, R.J.; Turman, B.N.

    1999-04-20T23:59:59.000Z

    Irradiation of red meat and poultry has been approved by the U.S. FDA, and the U.S. Department of Agriculture's rule for processing red meat is out for comment. Looking beyond the current issues of packaging materials, labeling, and consumer acceptance, this paper reviews the next step of implementation and how to remove, or at least reduce, the barriers to utilization. Polls of the user community identified their requirements for electron beam or x-ray processing of meat or poultry and their concerns about implementation for on-line processing. These needs and issues are compared to the capabilities of the accelerator industry. The critical issues of beam utilization and dose uniformity, factors affecting floor space requirements, and treatment costs are examined.

  6. Sub-10-nm electron-beam lithography for templated placement of colloidal quantum dots

    E-Print Network [OSTI]

    Manfrinato, Vitor Riseti

    2011-01-01T23:59:59.000Z

    This thesis presents the investigation of resolution limits of electron-beam lithography (EBL) at the sub-10-nm scale. EBL patterning was investigated at low electron energy (2 keV) in a converted scanning electron microscope ...

  7. Composition monitoring of electron beam melting processes using diode lasers

    SciTech Connect (OSTI)

    Berzins, L.V.

    1991-11-20T23:59:59.000Z

    Electron beam melting processes are used to produce high purity alloys for a wide range of applications. Real time monitoring of the alloy constituents, however, has historically been difficult. Absorption spectroscopy using diode lasers provides a means for measuring constituent densities, and hence alloy composition, in real time. Diode lasers are suggested because they are inexpensive and require little maintenance. There is increasing interest in the composition and quality control of titanium alloys used in aircraft parts. For this reason we describe a proposed system for composition monitoring of titanium alloys. Performance and cost of the proposed system is addressed. We discuss the applicability of this approach to other alloys.

  8. DMSE Electron Beam Instruments Facility | The Ames Laboratory

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625govInstrumentstdmadapInactiveVisitingContract Management Fermi SitePART I SECTION ADMSE Electron Beam Instruments

  9. Jefferson Lab electron beam charges up | Jefferson Lab

    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 SchoolIn12electron beam charges up Michael Schwartz Inside Business,

  10. Investigation of a direction sensitive sapphire detector stack at the 5 GeV electron beam at DESY-II

    E-Print Network [OSTI]

    O. Karacheban; K. Afanaciev; M. Hempel; H. Henschel; W. Lange; J. L. Leonard; I. Levy; W. Lohmann; S. Schuwalow

    2015-04-15T23:59:59.000Z

    Extremely radiation hard sensors are needed in particle physics experiments to instrument the region near the beam pipe. Examples are beam halo and beam loss monitoring systems at the Large Hadron Collider, FLASH or XFEL. Artificial diamond sensors are currently widely used as sensors in these systems. In this paper single crystal sapphire sensors are considered as a promising alternative. Industrially grown sapphire wafers are available in large sizes, are of low cost and, like diamond sensors, can be operated without cooling. Here we present results of an irradiation study done with sapphire sensors in a high intensity low energy electron beam. Then, a multichannel direction-sensitive sapphire detector stack is described. It comprises 8 sapphire plates of 1 cm^2 size and 525 micrometer thickness, metallized on both sides, and apposed to form a stack. Each second metal layer is supplied with a bias voltage, and the layers in between are connected to charge-sensitive preamplifiers. The performance of the detector was studied in a 5 GeV electron beam. The charge collection efficiency of the sensors was measured as a function of the bias voltage. It rises with the voltage, reaching about 10 % at 950 V. The signal size obtained from an electron crossing the stack at this voltage is about 22000 e, where e is the unit charge. Using the EUDET beam telescope, beam electrons trajectories where reconstructed, allowing to determine the position of the hits on the detector. The signal size is measured as a function of the hit position, showing variations of up to 20 % in the direction perpendicular to the beam and to the electric field. The measurement of the signal size as a function of the coordinate parallel to the electric field confirms the prediction that mainly electrons contribute to the signal. Also evidence for the presence of a polarization field was observed.

  11. Vacancies in Al after pulsed electron beam melting

    SciTech Connect (OSTI)

    Follstaedt, D.M.; Wampler, W.R.

    1981-02-01T23:59:59.000Z

    We have used transmission electron microscopy (TEM) to study the retention of vacancies in Al after rapid melting and resolidification of a thin (approx. 3 ..mu..m) surface layer using a pulsed (approx.50 ns) electron beam. After pulsing and aging at room temperature, TEM examination showed dislocation loops, which are interpreted to be due to the coalescence of the quenched-in vacancies on )111) planes as is the case for the loops observed in earlier furnace quenching studies. Our results indicate that the rapid melting and resolidification leaves a high vacancy concentration (approx.100 ppm) in the resolidified Al. Heat transport calculations show that cooling rates for the pulse heated samples (approx.10/sup 8/ K/s) are much higher than those achieved by conventional quenching techniques (approx. 10/sup 4/ K/s).

  12. Ion boundary conditions in semi-infinite fluid models of electron beam-plasma interaction

    SciTech Connect (OSTI)

    Levko, Dmitry [LAPLACE (Laboratoire Plasma et Conversion d'Energie), Universite de Toulouse, UPS, INPT Toulouse, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France)

    2014-10-15T23:59:59.000Z

    The modified Bohm criterion is derived for the plasma consisting of the monoenergetic electron beam and thermal electrons. This criterion allows us to define the accurate ion boundary conditions for semi-infinite collisionless fluid models of electron beam–plasma interaction. In the absence of electron beam, these boundary conditions give the classical sheath parameters. When the monoenergetic electron beam propagates through the plasma, the fluid model with proposed boundary conditions gives the results, which are in qualitative agreement with the results obtained earlier in M. Sharifian and B. Shokri, Phys. Plasmas 14, 093503 (2007). However, dynamics and parameters of the plasma sheath are different.

  13. The effect of head-on beam-beam compensation on the stochastic boundaries and particle diffusion in RHIC.

    SciTech Connect (OSTI)

    Abreu,N.; Beebe-Wang, J.; FischW; Luo, Y.; Robert-Demolaize, G.

    2008-06-23T23:59:59.000Z

    To compensate the effects from the head-on beam-beam interactions in the polarized proton operation in the Relativistic Heavy Ion Collider (RHIC), an electron lens (elens) is proposed to collide head-on with the proton beam. We used an extended version of SixTrack for multiparticle beam-beam simulation in order to study the effect of the e-lens on the stochastic boundary and also on diffusion. The stochastic boundary was analyzed using Lyapunov exponents and the diffusion was characterized as the increase in the rms spread of the action. For both studies the simulations were performed with and without the e-lens and with full and partial compensation. Using the simulated values of the diffusion an attempt to calculate the emittance growth rate is presented.

  14. Nondestructive evaluation of electron-beam braze joins

    SciTech Connect (OSTI)

    Boyd, D.M.; Shackelford, J.F.; Maxfield, B.W.; Taylor, G.M.

    1981-08-18T23:59:59.000Z

    A nondestructive evaluation (NDE) program has been carried out using holographic interferometry, microradiography, and eddy current testing for the inspection of electron beam braze joining of dissimilar metals. Stainless steel tubing was joined to a gold-copper disk using a Cusil (copper/silver) brazing alloy. Holographic interferometry provided an indirect measure of strength by detecting the plastic deformation occurring as a result of applying a stress. Microradiography with the aid of computer graphics displays provided a means of measuring braze penetration into the stainless steel tube. Correlation of results with metallographic examination and microhardness measurements show that holography and microradiography each provide quantitative braze quality rankings. Each method correctly identified variations in braze quality independent of electron beam power (the only processing variable in sample fabrication). Eddy current results were consistent with the other NDE methods but appear to be based on variation in surface topography rather than electrical conductivity. The usefulness of the eddy current method for this problem is questionable due to its sensitivity to the small, complex test piece geometry.

  15. Means for the focusing and acceleration of parallel beams of charged particles. [Patent application

    DOE Patents [OSTI]

    Maschke, A.W.

    1980-09-23T23:59:59.000Z

    Apparatus for focusing beams of charged particles comprising planar arrays of electrostatic quadrupoles. The array may be assembled from a single component which comprises a support plate containing uniform rows of poles. Each pole is separated by a hole through the plate designed to pass a beam. Two such plates may be positioned with their poles intermeshed to form a plurality of quadrupoles.

  16. 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

  17. TRANSVERSE ELECTRON BEAM DIAGNOSTICS AT THE VUV-FEL AT K. Honkavaara

    E-Print Network [OSTI]

    TRANSVERSE ELECTRON BEAM DIAGNOSTICS AT THE VUV-FEL AT DESY K. Honkavaara , F. L¨oehl, Hamburg. Catani, A. Cianchi, INFN-Roma2, 00133 Roma, Italy Abstract The VUV-FEL is a new free electron laser user tools and methods. At the VUV-FEL the transverse distribution of the electron beam is measured using

  18. Apparatus and method for compensating for electron beam emittance in synchronizing light sources

    DOE Patents [OSTI]

    Neil, G.R.

    1996-07-30T23:59:59.000Z

    A focused optical beam is used to change the path length of the core electrons in electron light sources thereby boosting their efficiency of conversion of electron beam energy to light. Both coherent light in the free electron laser and incoherent light in the synchrotron is boosted by this technique. By changing the path length of the core electrons by the proper amount, the core electrons are caused to stay in phase with the electrons in the outer distribution of the electron beam. This increases the fraction of the electron beam energy that is converted to light thereby improving the efficiency of conversion of energy to light and therefore boosting the power output of the free electron laser and synchrotron. 4 figs.

  19. Apparatus and method for compensating for electron beam emittance in synchronizing light sources

    DOE Patents [OSTI]

    Neil, George R. (Williamsburg, VA)

    1996-01-01T23:59:59.000Z

    A focused optical beam is used to change the path length of the core electrons in electron light sources thereby boosting their efficiency of conversion of electron beam energy to light. Both coherent light in the free electron laser and incoherent light in the synchrotron is boosted by this technique. By changing the path length of the core electrons by the proper amount, the core electrons are caused to stay in phase with the electrons in the outer distribution of the electron beam. This increases the fraction of the electron beam energy that is converted to light thereby improving the efficiency of conversion of energy to light and therefore boosting the power output of the free electron laser and synchrotron.

  20. Mass spectrometer with electron source for reducing space charge effects in sample beam

    DOE Patents [OSTI]

    Houk, Robert S.; Praphairaksit, Narong

    2003-10-14T23:59:59.000Z

    A mass spectrometer includes an ion source which generates a beam including positive ions, a sampling interface which extracts a portion of the beam from the ion source to form a sample beam that travels along a path and has an excess of positive ions over at least part of the path, thereby causing space charge effects to occur in the sample beam due to the excess of positive ions in the sample beam, an electron source which adds electrons to the sample beam to reduce space charge repulsion between the positive ions in the sample beam, thereby reducing the space charge effects in the sample beam and producing a sample beam having reduced space charge effects, and a mass analyzer which analyzes the sample beam having reduced space charge effects.

  1. Using a Relativistic Electron Beam to Generate Warm Dense Matter for Equation of State Studies

    SciTech Connect (OSTI)

    Berninger, M.

    2011-06-24T23:59:59.000Z

    Experimental equation-of-state (EOS) data are difficult to obtain for warm dense matter (WDM)–ionized materials at near-solid densities and temperatures ranging from a few to tens of electron volts–due to the difficulty in preparing suitable plasmas without significant density gradients and transient phenomena. We propose that the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility can be used to create a temporally stationary and spatially uniform WDM. DARHT has an 18 MeV electron beam with 2 kA of current and a programmable pulse length of 20 ns to 200 ns. This poster describes how Monte Carlo n-Particle (MCNP) radiation transport and LASNEX hydrodynamics codes were used to demonstrate that the DARHT beam is favorable for avoiding the problems that have hindered past attempts to constrain WDM properties. In our concept, a 60 ns pulse of electrons is focused onto a small, cylindrical (1 mm diameter × 1 mm long) foam target, which is inside a stiff high-heat capacity tube that both confines the WDM and allows pressure measurements. In our model, the foam is made of 30% density Au and the tamper is a B4C tube. An MCNP model of the DARHT beam investigated electron collisions and the amount of energy deposited in the foam target. The MCNP data became the basis for a LASNEX source model, where the total energy was distributed over a 60 ns time-dependent linear ramp consistent with the DARHT pulse. We used LASNEX to calculate the evolution of the foam EOS properties during and after deposition. Besides indicating that a ~3 eV Au plasma can be achieved, LASNEX models also showed that the WDM generates a shock wave into the tamper whose speed can be measured using photonic Doppler velocimetry. EOS pressures can be identified to better than 10% precision. These pressures can be correlated to energy deposition with electron spectrometry in order to obtain the Au EOS. Radial uniformity in the DARHT beam was also investigated. To further obtain uniform radial energy deposition, MCNP calculations were carried out with radial beam filters. Results are presented.

  2. Emittance Reduction between EBIS LINAC and Booster by Electron Beam Cooling; Is Single Pass Cooling Possible?

    SciTech Connect (OSTI)

    Hershcovitch,A.

    2008-04-01T23:59:59.000Z

    Electron beam cooling is examined as an option to reduce momentum of gold ions exiting the EBIS LINAC before injection into the booster. Electron beam parameters are based on experimental data (obtained at BNL) of electron beams extracted from a plasma cathode. Preliminary calculations indicate that single pass cooling is feasible; momentum spread can be reduced by more than an order of magnitude in less than one meter.

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

    E-Print Network [OSTI]

    Umstadter, Donald

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

  4. Electrostatic quadrupole array for focusing parallel beams of charged particles

    DOE Patents [OSTI]

    Brodowski, John (Smithtown, NY)

    1982-11-23T23:59:59.000Z

    An array of electrostatic quadrupoles, capable of providing strong electrostatic focusing simultaneously on multiple beams, is easily fabricated from a single array element comprising a support rod and multiple electrodes spaced at intervals along the rod. The rods are secured to four terminals which are isolated by only four insulators. This structure requires bias voltage to be supplied to only two terminals and eliminates the need for individual electrode bias and insulators, as well as increases life by eliminating beam plating of insulators.

  5. Theoretical Examination of Transfer Cavities in a Standing-wave Free-electron Laser Two-beam Accelerator

    E-Print Network [OSTI]

    Govil, R.

    2008-01-01T23:59:59.000Z

    Standing-Wave Free-Electron Laser Two-Beam Accelerator",the Standing-Wave Free-Electron Laser Two-Beam Accelerator",A.M. Sessler, "The Free-Electron Laser as a Power Source for

  6. Pulsed electron beam precharger. Final report, September 1, 1989--May 31, 1992

    SciTech Connect (OSTI)

    Finney, W.C. [ed.; Shelton, W.N.

    1992-12-31T23:59:59.000Z

    This is the fifth in a series of contracts and grants exploring the advanced particulate pollution control technology of electron beam precipitation. The project currently under contract with the Pittsburgh Energy Technology Center, US DOE, addresses the pressing problem of more efficiently controlling the emission of fine, high resistivity fly ash from low sulfur coal-burning power plants. As such, the project is an integral part of the DOE mission to advance technologies which provide for the safe and economically viable utilization of the nation`s large but potentially polluting coal resources. Within the University Coal Research Program of the DOE, the objective of the project is also consistent with the goal of improving the performance of electrostatic precipitators and possibly fabric filters through the use of a first-stage electron beam particle precharger. Reducing the emission of particulate matter from coal fired boilers is in the national interest from a respiratory health standpoint, while improved power efficiency of the removal process serves the goals of lowered energy consumption. In addition, an earlier spinoff of the ongoing program at FSU was the invention of a new technology using pulsed streamer corona for SO{sub 2} and NO{sub x} removal, the pulse energized electron reactor (PEER) process.

  7. Comparison of particle simulation with j-parc linac mebt beam test results

    SciTech Connect (OSTI)

    Ikegami, M.; Kato, T., Igarashi, Z.; Ueno, A.; Kondo, Y.; Ryne, R.; Qiang, J.

    2003-12-16T23:59:59.000Z

    The construction of the initial part of the J-PARC linac has been started at KEK for beam tests before moving to the JAERI Tokai campus, where J-PARC facility is finally to be constructed. The RFQ and MEBT (Medium Energy Beam Transport) has already been installed at KEK, and the beam test has been performed successfully. In this paper, the experimental results of the beam test are compared with simulation results with a 3D PIC (Particle-In-Cell) code, IMPACT.

  8. Analysis of electron-beam vaporization of refractory metals

    SciTech Connect (OSTI)

    Kheshgi, H.S.; Gresho, P.M.

    1986-09-01T23:59:59.000Z

    An electron beam is focussed onto a small area on the surface of a refractory metal to locally raise the temperature and vaporize metal. At high vaporization rates the hot area is on the surface of a churning liquid-metal pool contained in a solid-metal skull which sits in a cooled crucible. Inner workings of the process are revealed by analysis of momentum, energy, and mass transfer. At the surface high temperature causes high vaporization rate and high vapor thrust, depressing the vapor/liquid surface. In the liquid pool surface-tension gradients and thermal buoyancy drive a (typically) chaotic flow. In the solid skull thermal conductivity and contact resistance regulate the rate of heat transfer from pool to crucible. Analyses of these phenomena together reveal process performance sensitivities - e.g., to depression size or to magnitude of surface-tension gradients. 12 refs., 3 figs.

  9. Resolution Limits of Electron-Beam Lithography toward the Atomic Scale

    E-Print Network [OSTI]

    Zhang, Lihua

    We investigated electron-beam lithography with an aberration-corrected scanning transmission electron microscope. We achieved 2 nm isolated feature size and 5 nm half-pitch in hydrogen silsesquioxane resist. We also analyzed ...

  10. Comparison of Current Almond Pasteurization Methods and Electron Beam Irradiation as an Alternative

    E-Print Network [OSTI]

    Cuervo Pliego, Mary

    2012-02-14T23:59:59.000Z

    , almonds that were inoculated with S. Enteritidis PT 30 and S. Senftenberg, were treated with electron beam irradiation (e-beam), blanching and oil roasting. The thermal death time (D-value) for S. Enteritidis PT 30 when treated with e-beam was 0.90 kGy, 15...

  11. Low-energy run of Fermilab Electron Cooler's beam generation system

    SciTech Connect (OSTI)

    Prost, Lionel; Shemyakin, Alexander; /Fermilab; Fedotov, Alexei; Kewisch, Jorg; /Brookhaven

    2010-08-01T23:59:59.000Z

    As a part of a feasibility study of using the Fermilab Electron Cooler for a low-energy Relativistic Heavy Ion Collider (RHIC) run at Brookhaven National Laboratory (BNL), the cooler operation at 1.6 MeV electron beam energy was tested in a short beam line configuration. The main result of the study is that the cooler beam generation system is suitable for BNL needs. In a striking difference with running 4.3 MeV beam, no unprovoked beam recirculation interruptions were observed.

  12. A Monte-Carlo simulation of the equilibrium beam polarization in ultra-high energy electron(positron) storage rings

    E-Print Network [OSTI]

    Duan, Zhe; Barber, Desmond P; Qin, Qing

    2015-01-01T23:59:59.000Z

    With the recently emerging global interest in building a next generation of circular electron-positron colliders to study the properties of the Higgs boson, and other important topics in particle physics at ultra-high beam energies, it is also important to pursue the possibility of implementing polarized beams at this energy scale. It is therefore necessary to set up simulation tools to evaluate the beam polarization at these ultra-high beam energies. In this paper, a Monte-Carlo simulation of the equilibrium beam polarization based on the Polymorphic Tracking Code(PTC) is described. The simulations are for a model storage ring with parameters similar to those of proposed circular colliders in this energy range, and they are compared with the suggestion that there are different regimes for the spin dynamics underlying the polarization of a beam in the presence of synchrotron radiation at ultra-high beam energies. In particular, it has been suggested that the so-called "correlated" crossing of spin resonances ...

  13. Control of the chaotic velocity dispersion of a cold electron beam interacting with electrostatic waves

    E-Print Network [OSTI]

    Guido Ciraolo; Cristel Chandre; Ricardo Lima; Marco Pettini; Michel Vittot

    2006-07-31T23:59:59.000Z

    In this article we present an application of a method of control of Hamiltonian systems to the chaotic velocity diffusion of a cold electron beam interacting with electrostatic waves. We numerically show the efficiency and robustness of the additional small control term in restoring kinetic coherence of the injected electron beam.

  14. 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

  15. Modelling the Electron Beam Welding of Nuclear Reactor Pressure Vessel Steel

    E-Print Network [OSTI]

    Cambridge, University of

    Modelling the Electron Beam Welding of Nuclear Reactor Pressure Vessel Steel Christopher J. Duffy fabrication of thick-section steel for critical components such as reactor pressure vessels. Electron beam weld tests performed by Rolls-Royce and The Welding Institute of SA 508 Grade 3 and SA 508 Grade 4N

  16. 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

  17. 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

  18. Physics of a repetitively pulsed 10 kAmp electron beam accelerator

    SciTech Connect (OSTI)

    Fessenden, T.J.; Atchison, W.A.; Birx, D.L.; Briggs, R.J.; Clark, J.C.; Hester, R.E.; Neil, V.K.; Paul, A.C.; Rogers, D. Jr.; Struve, K.W.

    1981-01-01T23:59:59.000Z

    Some aspects of physics that contributed to design and operation of the ETA 10 kAmp electron accelerator are discussed. These include: the electron source, the emittance growth in the injector, beam transport through the accelerator, and the influence of the beam breakup accelerator instability.

  19. Optical Deflection and Temporal Characterization of an Ultrafast Laser-Produced Electron Beam

    E-Print Network [OSTI]

    Umstadter, Donald

    Optical Deflection and Temporal Characterization of an Ultrafast Laser-Produced Electron Beam show that the optical pulse with a0 0:5 imparts momentum to the electron beam, causing it to deflect optically driven x-ray sources based on nonlinear Thomson scattering [3­5]. A finite optical pulse imparts

  20. MIRCO-STRUCTURES OF RF SURFACES IN THE ELECTRON-BEAM-WELD REGIONS OF NIOBIUM

    E-Print Network [OSTI]

    Geng, Rong-Li

    MIRCO-STRUCTURES OF RF SURFACES IN THE ELECTRON-BEAM-WELD REGIONS OF NIOBIUM R.L. Gengyz , J-structures of RF surfaces in the electron-beam-weld (EBW) regions of niobium samples were studied. These surfaces.These observations have important impli- cations in explanations of the high-field-Q-drop of niobium superconducting

  1. Electron beam dynamics in the DARHT-II linear induction accelerator

    SciTech Connect (OSTI)

    Ekdahl, Carl A [Los Alamos National Laboratory; Abeyta, Epifanio O [Los Alamos National Laboratory; Aragon, Paul [Los Alamos National Laboratory; Archuleta, Rita [Los Alamos National Laboratory; Cook, Gerald [Los Alamos National Laboratory; Dalmas, Dale [Los Alamos National Laboratory; Esquibel, Kevin [Los Alamos National Laboratory; Gallegos, Robert A [Los Alamos National Laboratory; Garnett, Robert [Los Alamos National Laboratory; Harrison, James F [Los Alamos National Laboratory; Johnson, Jeffrey B [Los Alamos National Laboratory; Jacquez, Edward B [Los Alamos National Laboratory; Mccuistian, Brian T [Los Alamos National Laboratory; Montoya, Nicholas A [Los Alamos National Laboratory; Nath, Subrata [Los Alamos National Laboratory; Nielsen, Kurt [Los Alamos National Laboratory; Oro, David [Los Alamos National Laboratory; Prichard, Benjamin [Los Alamos National Laboratory; Rowton, Lawrence [Los Alamos National Laboratory; Sanchez, Manolito [Los Alamos National Laboratory; Scarpetti, Raymond [Los Alamos National Laboratory; Schauer, Martin M [Los Alamos National Laboratory; Seitz, Gerald [Los Alamos National Laboratory; Schulze, Martin [Los Alamos National Laboratory; Bender, Howard A [Los Alamos National Laboratory; Broste, William B [Los Alamos National Laboratory; Carlson, Carl A [Los Alamos National Laboratory; Frayer, Daniel K [Los Alamos National Laboratory; Johnson, Douglas E [Los Alamos National Laboratory; Tom, C Y [Los Alamos National Laboratory; Trainham, C [NSTEC/STL; Williams, John [Los Alamos National Laboratory; Genoni, Thomas [VOSS; Hughes, Thomas [VOSS; Toma, Carsten [VOSS

    2008-01-01T23:59:59.000Z

    The DARHT-II linear induction accelerator (LIA) accelerates a 2-kA electron beam to more than 17 MeV. The beam pulse has a greater than 1.5-microsecond flattop region over which the electron kinetic energy is constant to within 1%. The beam dynamics are diagnosed with 21 beam-position monitors located throughout the injector, accelerator, and after the accelerator exit, where we also have beam imaging diagnostics. We discuss the tuning of the injector and accelerator, and present data for the resulting beam dynamics. We discuss the tuning procedures and other methods used to minimize beam motion, which is undesirable for its application as a bremsstrahlung source for multi-pulse radiography of exlosively driven hydrodynamic experiments. We also present beam stability measurements, which we relate to previous stability experiments at lower current and energy.

  2. Dynamics of a beam of hot electrons propagating through a plasma in the presence of nonthermal electrons

    SciTech Connect (OSTI)

    Khalilpour, H.; Moslehi-Fard, M. [Faculty of Physics, Tabriz University, 51664 Tabriz (Iran, Islamic Republic of); Foroutan, G. [Department of Physics, Faculty of Science, Sahand University of Technology, 51335-1996 Tabriz (Iran, Islamic Republic of); School of Physics, University of Sydney, Sydney, New South Wales 2006 (Australia); Li, B.; Robinson, P. A. [School of Physics, University of Sydney, Sydney, New South Wales 2006 (Australia)

    2009-07-15T23:59:59.000Z

    The dynamics of a beam of hot electrons traveling through a cold plasma and the generation of Langmuir waves are investigated in the presence of a nonthermal tail of electrons in the background distribution function. Using quasilinear simulations, it is shown that in the presence of the nonthermal electrons, the relaxation of the beam distribution function in velocity space is retarded and the Langmuir waves are strongly damped at low velocities. The average velocity of beam propagation is almost constant but its magnitude is larger in the presence of nonthermal electrons than their absence. It is found that the self-similarity of the system is preserved in the presence of nonthermal electrons. The effects of nonthermal electrons on the evolution of gas-dynamical parameters of the beam, including the height of plateau in the beam distribution function, its upper and lower velocity boundaries, and beam velocity width, are also studied. It is found that initially the values of the upper and lower velocity boundaries are almost unaltered, but at large times the lower (upper) boundary velocity is larger (smaller) in the presence of nonthermal electrons than without the nonthermal electrons.

  3. Chemical Imaging Analysis of Environmental Particles Using the...

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

    Imaging Analysis of Environmental Particles Using the Focused Ion BeamScanning Electron Microscopy Technique: Chemical Imaging Analysis of Environmental Particles Using the...

  4. ablation particle beam: Topics by E-print Network

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

    LASer in Hamburg) provides ultra-intense femtosecond radiation and laser optics: UV, XUV, and X-ray lasers; (140.2600) Lasers and laser optics: Free electron lasers;...

  5. Optical trapping and rotation of airborne absorbing particles with a single focused laser beam

    SciTech Connect (OSTI)

    Lin, Jinda; Li, Yong-qing, E-mail: liy@ecu.edu [Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353 (United States)] [Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353 (United States)

    2014-03-10T23:59:59.000Z

    We measure the periodic circular motion of single absorbing aerosol particles that are optically trapped with a single focused Gaussian beam and rotate around the laser propagation direction. The scattered light from the trapped particle is observed to be directional and change periodically at 0.4–20?kHz. The instantaneous positions of the moving particle within a rotation period are measured by a high-speed imaging technique using a charge coupled device camera and a repetitively pulsed light-emitting diode illumination. The centripetal acceleration of the trapped particle as high as ?20 times the gravitational acceleration is observed and is attributed to the photophoretic forces.

  6. Enhanced modified faraday cup for determination of power density distribution of electron beams

    DOE Patents [OSTI]

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

    2001-01-01T23:59:59.000Z

    An improved tomographic technique for determining the power distribution of an electron or ion beam using electron beam profile data acquired by an enhanced modified Faraday cup to create an image of the current density in high and low power ion or electron beams. A refractory metal disk with a number of radially extending slits, one slit being about twice the width of the other slits, is placed above a Faraday cup. The electron or ion beam is swept in a circular pattern so that its path crosses each slit in a perpendicular manner, thus acquiring all the data needed for a reconstruction in one circular sweep. The enlarged slit enables orientation of the beam profile with respect to the coordinates of the welding chamber. A second disk having slits therein is positioned below the first slit disk and inside of the Faraday cup and provides a shield to eliminate the majority of secondary electrons and ions from leaving the Faraday cup. Also, a ring is located below the second slit disk to help minimize the amount of secondary electrons and ions from being produced. In addition, a beam trap is located in the Faraday cup to provide even more containment of the electron or ion beam when full beam current is being examined through the center hole of the modified Faraday cup.

  7. axisymmetric electron beam: Topics by E-print Network

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

    dominated beams F. Filbet 1 , J.-L. Lemaire Filbet, Francis 2 From x-ray telescopes to neutron scattering: using axisymmetric mirrors to focus a neutron beam CERN Preprints...

  8. Nanostructure fabrication by electron and ion beam patterning of nanoparticles

    E-Print Network [OSTI]

    Kong, David Sun, 1979-

    2004-01-01T23:59:59.000Z

    Two modes of energetic beam-mediated fabrication have been investigated, namely focused ion beam (FIB) direct-writing of nanoparticles, and a technique for electrostatically patterning ionized inorganic nanoparticles, ...

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

    E-Print Network [OSTI]

    Lemery, Francois

    2015-01-01T23:59:59.000Z

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

  10. Possibilities of alpha-particle diagnostics in future tokamaks using helium and lithium beam injection

    SciTech Connect (OSTI)

    Gorelenkov, N.N.; Krasilnikov, A.V. (I.V. Kurchatov Inst. of Atomic Energy, Moscow (SU))

    1991-03-01T23:59:59.000Z

    This paper considers the possibility of using active charge-exchange (CX) diagnostics based on helium and lithium beam injection to investigate the confined alpha-particle distribution function in future fusion experiments. The required helium beam densities are determined by mathematic modeling of the physical processes (double CX, attenuation of the doping beam, and CX flow, taking into account the step process). They are found to be {approximately}1 A for a 40-keV beam for thermalized (ash) alpha-particle diagnostics and 30 to 600 MA for a 0.35 to 0.65 MeV/amu HeH{sup +} ion source for hot alpha-particle diagnostics. A {sup 3}He beam with energy of 500 keV (He{sup +} ion source) and intensity of 0.1 to 3 A is proposed for measurement of the alpha-particle distribution function in the energy range of 0.2 to 2 MeV.

  11. The evaluation of cleanness by electron beam button melting and other methods - a review

    SciTech Connect (OSTI)

    Quested, P.N.; Hayes, D.M. [National Physical Lab., Middlesex (United Kingdom)

    1994-12-31T23:59:59.000Z

    The accurate determination of both the number and size distribution of inclusions in superclean materials is difficult. Some of the methods used for nickel-base alloys and steels are briefly reviewed; all the methods have problems associated with them. Electron Beam Button Melting (EBBM) and the new technique of Cold Crucible Melting (CCM) as methods of concentrating the inclusions offer the advantage of sampling large volumes of material quickly. The number, size and composition of the entrapped particles can be determined using Scanning Electron Microscopy, (SEM). Both techniques may be used for semi-quantitative assessment such as ranking different heats of materials but care is required with quantitative evaluation. The mechanisms controlling inclusion collection efficiency for EBBM are reviewed including investigations with samples doped with particles of known size and number and assessing recovery rates on button rafts. In EBBM low power melting and solidification programmes are recommended to minimise the melting or sintering of the inclusions and melt compositions, particularly sulphur, have a major effect on the efficiency of inclusion collection. Under favourable conditions collection efficiencies of 90-95% can be achieved. As a result of these types of studies a draft code of practice for the evaluation of alloy cleanness by EBBM has been prepared. Cold crucible melting is an attractive alternative to EBBM for cleanness evaluation. Trials have established that collection efficiencies of 80-85% can be achieved with this method but SEM examination of the buttons is more time consuming compared with EBBM.

  12. Particle beam self-modulation instability in tapered and inhomogeneous plasma

    SciTech Connect (OSTI)

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

    2011-12-28T23:59:59.000Z

    The particle beam self-modulation instability in tapered and inhomogeneous plasmas is analyzed via an evolution equation for the beam radius. For a sufficiently fast taper the instability is suppressed, and the condition for growth suppression is derived. The form of the taper to phase lock a trailing witness bunch in the plasma wave driven by a self-modulated beam is determined, which can increase the energy gain by several orders of magnitude. Growth of the instability places stringent constraints on the initial background plasma density fluctuations.

  13. Precessed electron beam electron energy loss spectroscopy of graphene: Beyond channelling effects

    SciTech Connect (OSTI)

    Yedra, Ll.; Estradé, S., E-mail: sestrade@ub.edu [LENS, MIND-IN2UB, Departament d'Electrònica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); TEM-MAT, CCiT, Universitat de Barcelona, Solé i Sabarís 1, 08028 Barcelona (Spain); Torruella, P.; Eljarrat, A.; Peiró, F. [LENS, MIND-IN2UB, Departament d'Electrònica, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Darbal, A. D. [AppFive LLC, 1095 W Rio Salado Pkway, Suite 110, Tempe, Arizona 85281 (United States); Weiss, J. K. [AppFive LLC, 1095 W Rio Salado Pkway, Suite 110, Tempe, Arizona 85281 (United States); NanoMEGAS SPRL, Blvd. Edmond Machtens 79, B-1080 Brussels (Belgium)

    2014-08-04T23:59:59.000Z

    The effects of beam precession on the Electron Energy Loss Spectroscopy (EELS) signal of the carbon K edge in a 2 monolayer graphene sheet are studied. In a previous work, we demonstrated the use of precession to compensate for the channeling-induced reduction of EELS signal when in zone axis. In the case of graphene, no enhancement of EELS signal is found in the usual experimental conditions, as graphene is not thick enough to present channeling effects. Interestingly, though it is found that precession makes it possible to increase the collection angle, and, thus, the overall signal, without a loss of signal-to-background ratio.

  14. A STEADY-STATE FEL: PARTICLE DYNAMICS IN THE FEL PORTION OF A TWO-BEAM ACCELERATOR

    E-Print Network [OSTI]

    Sternbach, E.

    2008-01-01T23:59:59.000Z

    September 8-13, 1985 A STEADY-STATE FEL: PARTICLE DYNAMICSIN THE FEL PORTION OF A TWO-BEAM ACCELERATOR E. SternbachLBL-19939 A STEADY-STATE FEL: PARTICLE DYNAMICS IN THE FEL

  15. Properties of Inconel 625 Mesh Structures Grown by Electron Beam Additive Manufacturing

    SciTech Connect (OSTI)

    List III, Frederick Alyious [ORNL; Dehoff, Ryan R [ORNL; Lowe, Larry E [ORNL; Sames, William J [ORNL

    2014-01-01T23:59:59.000Z

    Relationships between electron beam parameters (beam current, beam speed, and beam focus) and physical properties (mass, diameter, elastic modulus, and yield strength) have been investigated for Inconel 625 mesh cubes fabricated using an additive manufacturing technology based on electron beam melting. The elastic modulus and yield strength of the mesh cubes have been systematically varied by approximately a factor of ten by changing the electron beam parameters. Simple models have been used to understand better these relationships. Structural anisotropies of the mesh associated with the layered build architecture have been observed and may contribute, along with microstructural anisotropies, to the anisotropic mechanical properties of the mesh. Knowledge of this kind is likely applicable to other metal and alloy systems and is essential to rapidly realize the full potential of this burgeoning technology.

  16. Cherenkov radiation and pair production by particles traversing laser beams

    E-Print Network [OSTI]

    I. M. Dremin

    2002-03-01T23:59:59.000Z

    It is shown that Cherenkov radiation can be observed at TESLA in electron collisions with optical laser pulses. The prospects for it to be observed at SLC, LEP, LHC and RHIC are discussed. The conclusions are compared with results for pair production.

  17. Measuring of plasma properties induced by non-vacuum electron beam welding

    SciTech Connect (OSTI)

    Reisgen, U.; Schleser, M.; Abdurakhmanov, A. [RWTH Aachen University ISF-Welding and Joining Institute, 52062 Aachen (Germany); Gumenyuk, A. [BAM Federal Institute for Materials Research and Testing, 12205 Berlin (Germany)

    2012-01-15T23:59:59.000Z

    Electron beam plasma measurement was realised by means of DIABEAM system invented by ISF RWTH Aachen. The Langmuir probe method is used for measurement. The relative simplicity of the method and the possibility of dispersion of high power on the probe allow its application for the investigation of high-power electron beams. The key element of the method is a rotating thin tungsten wire, which intersects the beam transversely on its axis and collects part of the current by itself. The signals, which are registered in the DIABEAM as a voltage, were taken in the form of amplitude. The conversion of the probe current into the distribution along the beam radius was realised using the Abel's method. A voltage-current characteristic was built for the beam current. The local electron density as well as the electron temperature, the floating potential and the plasma potential were measured and calculated by means of this characteristic.

  18. Plasma Panel Sensors for Particle and Beam Detection

    E-Print Network [OSTI]

    Peter S. Friedman; Robert Ball; James R. Beene; Yan Benhammou; E. H. Bentefour; J. W. Chapman; Erez Etzion; Claudio Ferretti; Nir Guttman; Daniel S. Levin; Meny Ben-Moshe; Yiftah Silver; Robert L. Varner; Curtis Weaverdyck; Bing Zhou

    2012-11-23T23:59:59.000Z

    The plasma panel sensor (PPS) is an inherently digital, high gain, novel variant of micropattern gas detectors inspired by many operational and fabrication principles common to plasma display panels (PDPs). The PPS is comprised of a dense array of small, plasma discharge, gas cells within a hermetically-sealed glass panel, and is assembled from non-reactive, intrinsically radiation-hard materials such as glass substrates, metal electrodes and mostly inert gas mixtures. We are developing the technology to fabricate these devices with very low mass and small thickness, using gas gaps of at least a few hundred micrometers. Our tests with these devices demonstrate a spatial resolution of about 1 mm. We intend to make PPS devices with much smaller cells and the potential for much finer position resolutions. Our PPS tests also show response times of several nanoseconds. We report here our results in detecting betas, cosmic-ray muons, and our first proton beam tests.

  19. 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.

  20. Standard practice for dosimetry in electron beam and X-Ray (Bremsstrahlung) irradiation facilities for food processing

    E-Print Network [OSTI]

    International Organization for Standardization. Geneva

    2005-01-01T23:59:59.000Z

    Standard practice for dosimetry in electron beam and X-Ray (Bremsstrahlung) irradiation facilities for food processing

  1. Transport and Non-Invasive Position Detection of Electron Beams from Laser-Plasma Accelerators

    SciTech Connect (OSTI)

    Osterhoff, Jens; Sokollik, Thomas; Nakamura, Kei; Bakeman, Michael; Weingartner, R; Gonsalves, Anthony; Shiraishi, Satomi; Lin, Chen; vanTilborg, Jeroen; Geddes, Cameron; Schroeder, Carl; Esarey, Eric; Toth, Csaba; DeSantis, Stefano; Byrd, John; Gruner, F; Leemans, Wim

    2011-07-20T23:59:59.000Z

    The controlled imaging and transport of ultra-relativistic electrons from laser-plasma accelerators is of crucial importance to further use of these beams, e.g. in high peak-brightness light sources. We present our plans to realize beam transport with miniature permanent quadrupole magnets from the electron source through our THUNDER undulator. Simulation results demonstrate the importance of beam imaging by investigating the generated XUV-photon flux. In addition, first experimental findings of utilizing cavity-based monitors for non-invasive beam-position measurements in a noisy electromagnetic laser-plasma environment are discussed.

  2. Analytical formula of Free Electron Laser exponential gain for non-resonant electron beam

    E-Print Network [OSTI]

    Jia, Qika

    2014-01-01T23:59:59.000Z

    The FEL gain formulas for non-resonant case are studied. For the mono-energetic and non-resonant electron beam, the exact expression of the solution of the FEL characteristic cubic equation is obtained with a form much more simple than that in the literatures, and the gain length as the function of the detuning parameter is explicitly given, then the gain for different detuning parameter and from low to high can be easily calculated. A simplified approximation formula is also given for the exponential gain calculation in the non-resonant case. For the case of the electron beam with an energy spread, the solution of the characteristic cubic equation is given explicitly for rectangular energy distribution and Lorentz distribution, respectively. Moreover the explicit expression also can be used for the solution of the characteristic cubic equation including the impact of the space charge. The transition from the low gain to the high gain is analyzed. The variations of the gain bandwidth and of the detuning param...

  3. Reasons for superior mechanical and corrosion properties of 2219 aluminum alloy electron beam welds

    SciTech Connect (OSTI)

    Koteswara Rao, S.R. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras, Chennai-600 036 (India)]. E-mail: sajjarkr@yahoo.com; Madhusudhan Reddy, G. [Defense Metallurgical Research Laboratory, Hyderabad-500 058 (India); Srinivasa Rao, K. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras, Chennai-600 036 (India); Kamaraj, M. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras, Chennai-600 036 (India); Prasad Rao, K. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Madras, Chennai-600 036 (India)

    2005-11-15T23:59:59.000Z

    Electron beam welds of aluminum alloy 2219 offer much higher strength compared to gas tungsten arc welds of the same alloy and the reasons for this have not been fully explored. In this study both types of welds were made and mechanical properties were evaluated by tensile testing and pitting corrosion resistance by potentio dynamic polarization tests. It is shown that electron beam welds exhibit superior mechanical and corrosion properties. The weld metals have been characterized by scanning electron microscopy; transmission electron microscopy and electron probe micro analysis. Presence of partially disintegrated precipitates in the weld metal, finer micro porosity and uniform distribution of copper in the matrix were found to be the reasons for superior properties of electron beam welds apart from the fine equiaxed grain structure. Transmission electron micrographs of the heat affected zones revealed the precipitate disintegration and over aging in gas tungsten arc welds.

  4. Neutral Beam Injection Experiments and Related Behavior of Neutral Particles in the GAMMA 10 Tandem Mirror

    SciTech Connect (OSTI)

    Nakashima, Y. [Plasma Research Center, University of Tsukuba (Japan); Watanabe, K. [Plasma Research Center, University of Tsukuba (Japan); Higashizono, Y. [Plasma Research Center, University of Tsukuba (Japan); Ohki, T. [Plasma Research Center, University of Tsukuba (Japan); Ogita, T. [Plasma Research Center, University of Tsukuba (Japan); Shoji, M. [National Institute for Fusion Science(Japan); Kobayashi, S. [Institute of Advanced Energy, Kyoto University (Japan); Islam, M.K. [Plasma Research Center, University of Tsukuba (Japan); Kubota, Y. [Plasma Research Center, University of Tsukuba (Japan); Yoshikawa, M. [Plasma Research Center, University of Tsukuba (Japan); Kobayashi, T. [Plasma Research Center, University of Tsukuba (Japan); Yamada, M. [Plasma Research Center, University of Tsukuba (Japan); Murakami, R. [Plasma Research Center, University of Tsukuba (Japan); Cho, T. [Plasma Research Center, University of Tsukuba (Japan)

    2005-01-15T23:59:59.000Z

    Results of neutral beam injection (NBI) experiments in the GAMMA 10 tandem mirror plasmas are presented together with the neutral particle behavior observed in the experiments. A hydrogen neural beam was injected into the hot-ion-mode plasmas by using the injector installed in the central-cell for the plasma heating and fueling. High-energy ions produced by NBI were observed and its energy distribution was measured for the first time with a neutral particle analyzer installed in the central-cell. The temporal and spatial behavior of hydrogen was observed with axially aligned H{sub {alpha}} detectors installed from the central midplane to anchor-cell. Enhancement of hydrogen recycling due to the beam injection and the cause of the observed decrease in plasma diamagnetism are discussed. The Monte-Carlo code DEGAS for neutral transport simulation was applied to the GAMMA 10 central-cell and a 3-dimensional simulation was performed in the NBI experiment. Localization of neutral particle during the beam injection is investigated based on the simulation and it was found that the increased recycling due to the beam injection was dominant near the injection port.

  5. Electron-beam envelopes and matching for a combined wiggler and alternating-gradient quadrupole channel

    SciTech Connect (OSTI)

    Wang, T.F.; Cooper, R.K.

    1985-01-01T23:59:59.000Z

    This work studies the electron-beam envelopes and matching for a combined wiggler and alternating-gradient quadrupole field for a free-electron laser (FEL) that will be operated in the VUV or XUV wavelength region. The quadrupole field is assumed to vary continuously along the symmetry axis. The linearized equations of electron motion are solved analytically by using the two-scale perturbation method for a plane polarized wiggler. The electron-beam envelopes and the envelope equations, as well as the matching conditions in phase space, are obtained from the electron trajectories. A comparison with the numerical solution is presented.

  6. Three-dimensional particle-in-cell simulation of electron acceleration by Langmuir waves in an inhomogeneous plasma

    SciTech Connect (OSTI)

    Pechhacker, R.; Tsiklauri, D. [School of Physics and Astronomy, Queen Mary University of London, London E1 4NS (United Kingdom)] [School of Physics and Astronomy, Queen Mary University of London, London E1 4NS (United Kingdom)

    2014-01-15T23:59:59.000Z

    A possible solution to the unexplained high intensity hard x-ray emission observable during solar flares was investigated via 3D fully relativistic, electromagnetic particle-in-cell simulations with realistic ion to electron mass ratio. A beam of accelerated electrons was injected into a magnetised, Maxwellian, homogeneous, and inhomogeneous background plasma. The electron distribution function was unstable to the beam-plasma instability and was shown to generate Langmuir waves, while relaxing to plateau formation. In order to estimate the role of the background density gradient on an unbound (infinite spatial extent) beam, three different scenarios were investigated: (a) a uniform density background; (b) a weak density gradient, n{sub e,R}/n{sub e,L}?=?3; (c) a strong gradient case, n{sub e,R}/n{sub e,L}?=?10, where n{sub e,R} and n{sub e,L} denote background electron densities on the left and right edges of the simulation box, respectively. The strong gradient case produced the largest fraction of electrons beyond 15v{sub th}. Furthermore, two cases (uniform and strong gradient background) with spatially localized beam injections were performed aiming to show drifts of the generated Langmuir wave wavenumbers, as suggested in previous studies. For the strong gradient case, the Langmuir wave power is shown to drift to smaller wavenumbers, as found in previous quasi-linear simulations.

  7. Extraction of a steady state electron beam from HCD plasmas for EBIS applications

    SciTech Connect (OSTI)

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

    1988-01-01T23:59:59.000Z

    Experiments to extract high brightness electron beams from hollow cathode discharge plasmas are now in progress. A unique feature of these plasmas, which in principle can facilitate the extraction of large current low emittance electron beams, is the existence of a relatively high energy electron population with a very narrow energy spread. This electron population was identified in a self-extraction experiment, which yielded a 35 eV, 600 mA electron beam with parallel energy spread of less than 0.5 eV. Application of a very modest extraction voltage yielded a steady state extracted electron beam current of 6.5 A of which 5.7 had a preacceleration parallel energy spread of no more than 0.25 eV. The end result of this endeavor would be an electron beam current to 6 A even though, preliminary results strongly suggest that much larger electron beam currents can be produced. 6 refs., 4 figs.

  8. Effects of electron beam irradiation on polyamide 12 with fiberglass reinforcement

    SciTech Connect (OSTI)

    Jeun, Joon-Pyo; Shin, Bum-Sik; Kim, Hyun-Bin; Nho, Young-Chang; Kang, Phil-Hyun [Radiation Research Division for Industry and Environment, Korea Atomic Energy Research Institute, 1266 Shinjeong-dong Jeongeup-si Jellabuk-do 580-185 (Korea, Republic of)

    2010-06-02T23:59:59.000Z

    In the present study, the effects of electron beam irradiation of polyamide 12 (PA12) with fiberglass reinforcement on the thermal and wear properties were investigated. Electron beam irradiation of PA 12 was carried out over a range of irradiation doses (100-600 kGy) in air. The gel formation in the presence of a curing agent was dependent on the radiation doses. The thermal properties of irradiated PA 12 were studied in the temperature region 50-250 deg. C to observe the changes in the melting point with radiation dose. The dimensional stability was significantly increased by electron beam irradiation and the related crosslinking of the PA 12.

  9. Numerical studies of emittance exchange in 2-D charged-particle beams

    SciTech Connect (OSTI)

    Guy, F.W.

    1986-01-01T23:59:59.000Z

    We describe results obtained from a two-dimensional particle-following computer code that simulates a continuous, nonrelativistic, elliptical charged-particle beam with linear continuous focusing. Emittances and focusing strengths can be different in the two transverse directions. The results can be applied, for example, for a quadrupole transport system in a smooth approximation to a real beam with unequal emittances in the two planes. The code was used to study emittance changes caused by kinetic-energy exchange between transverse directions and by shifts in charge distributions. Simulation results for space-charge-dominated beams agree well with analytic formulas. From simulation results, an empirical formula was developed for a ''partition parameter'' (the ratio of kinetic energies in the two directions) as a function of initial conditions and beamline length. Quantitative emittance changes for each transverse direction can be predicted by using this parameter. Simulation results also agree with Hofmann's generalized differential equation relating emittance and field energy.

  10. 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...

  11. Beam Position Monitor Electronics Upgrade for Fermilab Switchyard

    E-Print Network [OSTI]

    Stabile, P; Fitzgerald, J A; Liu, N; Morris, D K; Prieto, P S; Seraphin, J P

    2015-01-01T23:59:59.000Z

    The beam position monitor (BPM) system for Fermilab Switchyard (SY) provides the position, intensity and integrated intensity of the 53.10348 MHz RF bunched resonant extracted beam from the Main Injector over 4 seconds of spill. The total beam intensity varies from 1x10^11 to 1x10^13 protons. The spill is measured by stripline beam postion monitors and resonant circuit. The BPMs have an external resonant circuit tuned to 53.10348 MHz. The corresponding voltage signal out of the BPM has been estimated to be between -110 dBm and -80 dBm.

  12. area electron beam: Topics by E-print Network

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

    semiconductor. In particular, focused ion beam (FIB) milling can result in physical damage, implantation and doping of the specimen surface with Ga, as well as thickness...

  13. COHERENT INFRARED RADIATION FROM THE ALS GENERATED VIA FEMTOSECOND LASER MODULATION OF THE ELECTRON BEAM*

    E-Print Network [OSTI]

    the energy of an ultra-short (~ 30 micron) slice of a stored electron bunch as they co-propagate throughCOHERENT INFRARED RADIATION FROM THE ALS GENERATED VIA FEMTOSECOND LASER MODULATION OF THE ELECTRON Interaction of an electron beam with a femtosecond laser pulse co-propagating through a wiggler at the ALS

  14. Investigation of an electron beam evaporative source: Part 1, Theory; Part 2, Measurements

    SciTech Connect (OSTI)

    Sze, J.S.; Self, S.A. (Lawrence Livermore National Lab., CA (USA))

    1989-09-14T23:59:59.000Z

    A theory for evaluating the performance parameters of linear electron beam evaporative source is presented. The electron beam is considered to be generated from a linear gun and its trajectory is curved by a uniform magnetic field onto a target. A model has been developed to estimate the trajectory of the electron beam. The performance of the electron gun is characterized by two coefficients: {alpha}, the divergence effect of the beam as it enters into the electric field free space region, and {Beta}, the space charge parameter, which is proportional to the magnitude of the current density of the beam. These two parameters determine the location (angular position) of the beam waist and the current density at the target. In addition, neutralization of the electron space charge by vapor ions generated near the target is considered. A discussion is also given of the shape of the depression in the surface of the molten metal, which is due to the pressure on the surface associated with the momentum recoil from the evaporative vapor flux. By relating the characteristic depth and width of the depression to magnitude and the shape of the pressure profile, useful analytical and numerical results are presented for a given pressure profile. The implication of the results for the design of electron beam evaporative sources are also discussed. Measurements are discussed a the end of the paper. 11 refs., 15 figs.

  15. PARTICLE ACCELERATION AND MAGNETIC FIELD GENERATION IN ELECTRON-POSITRON RELATIVISTIC SHOCKS

    E-Print Network [OSTI]

    Nishikawa, Ken-Ichi

    PARTICLE ACCELERATION AND MAGNETIC FIELD GENERATION IN ELECTRON-POSITRON RELATIVISTIC SHOCKS K are responsible for particle (electron, positron, and ion) acceleration. Using a three-dimensional relativistic electromagnetic particle (REMP) code, we have investigated particle acceleration associated with a relativistic

  16. System for tomographic determination of the power distribution in electron beams

    DOE Patents [OSTI]

    Elmer, J.W.; Teruya, A.T.; O`Brien, D.W.

    1995-11-21T23:59:59.000Z

    A tomographic technique for measuring the current density distribution in electron beams using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams. The modified Faraday cup includes a narrow slit and is rotated by a stepper motor and can be moved in the x, y and z directions. The beam is swept across the slit perpendicular thereto and controlled by deflection coils, and the slit rotated such that waveforms are taken every few degrees form 0{degree} to 360{degree} and the waveforms are recorded by a digitizing storage oscilloscope. Two-dimensional and three-dimensional images of the current density distribution in the beam can be reconstructed by computer tomography from this information, providing quantitative information about the beam focus and alignment. 12 figs.

  17. System for tomographic determination of the power distribution in electron beams

    DOE Patents [OSTI]

    Elmer, John W. (Pleasanton, CA); Teruya, Alan T. (Livermore, CA); O'Brien, Dennis W. (Livermore, CA)

    1995-01-01T23:59:59.000Z

    A tomographic technique for measuring the current density distribution in electron beams using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams. The modified Faraday cup includes a narrow slit and is rotated by a stepper motor and can be moved in the x, y and z directions. The beam is swept across the slit perpendicular thereto and controlled by deflection coils, and the slit rotated such that waveforms are taken every few degrees form 0.degree. to 360.degree. and the waveforms are recorded by a digitizing storage oscilloscope. Two-dimensional and three-dimensional images of the current density distribution in the beam can be reconstructed by computer tomography from this information, providing quantitative information about the beam focus and alignment.

  18. System for tomographic determination of the power distribution in electron beams

    DOE Patents [OSTI]

    Elmer, J.W.; Teruya, A.T.; O'Brien, D.W.

    1995-01-17T23:59:59.000Z

    A tomographic technique is disclosed for measuring the current density distribution in electron beams using electron beam profile data acquired from a modified Faraday cup to create an image of the current density in high and low power beams. The modified Faraday cup includes a narrow slit and is rotated by a stepper motor and can be moved in the x, y and z directions. The beam is swept across the slit perpendicular thereto and controlled by deflection coils, and the slit rotated such that waveforms are taken every few degrees form 0[degree] to 360[degree] and the waveforms are recorded by a digitizing storage oscilloscope. Two-dimensional and three-dimensional images of the current density distribution in the beam can be reconstructed by computer tomography from this information, providing quantitative information about the beam focus and alignment. 12 figures.

  19. Investigations of large area electron beam diodes for excimer lasers. Final report

    SciTech Connect (OSTI)

    Not Available

    1993-12-31T23:59:59.000Z

    This report summarizes the results of a one year research program at the University of Michigan to investigate the physics and technology of microsecond electron beam diodes. These experiments were performed on the Michigan Electron Long Beam Accelerator (MELBA) at parameters: Voltage {equals} {minus}0.65 to {minus}0.9 MV, current {equals} 1 {minus}50 kA, and pulselength {equals} 0.5 {minus} 5 microseconds. Major accomplishments include: (1) the first two-wavelength (CO2 and HeNe) laser deflection measurements of diode plasma and neutrals; (2) measurements of the effects on magnetic field gradient on microsecond diode closure; (3) demonstration of good fidelity of processed x-ray signals as a diagnostic of beam voltage; (4) extended-pulselength scaling of electron beam diode arcing and diode closure; and (5) innovative Cerenkov plate diagnostics of e-beam dynamics.

  20. Monte Carlo based beam model using a photon MLC for modulated electron radiotherapy

    SciTech Connect (OSTI)

    Henzen, D., E-mail: henzen@ams.unibe.ch; Manser, P.; Frei, D.; Volken, W.; Born, E. J.; Vetterli, D.; Chatelain, C.; Fix, M. K. [Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, CH-3010 Berne (Switzerland)] [Division of Medical Radiation Physics and Department of Radiation Oncology, Inselspital, Bern University Hospital, and University of Bern, CH-3010 Berne (Switzerland); Neuenschwander, H. [Clinic for Radiation-Oncology, Lindenhofspital Bern, CH-3012 Berne (Switzerland)] [Clinic for Radiation-Oncology, Lindenhofspital Bern, CH-3012 Berne (Switzerland); Stampanoni, M. F. M. [Institute for Biomedical Engineering, ETH Zürich and Paul Scherrer Institut, CH-5234 Villigen (Switzerland)] [Institute for Biomedical Engineering, ETH Zürich and Paul Scherrer Institut, CH-5234 Villigen (Switzerland)

    2014-02-15T23:59:59.000Z

    Purpose: Modulated electron radiotherapy (MERT) promises sparing of organs at risk for certain tumor sites. Any implementation of MERT treatment planning requires an accurate beam model. The aim of this work is the development of a beam model which reconstructs electron fields shaped using the Millennium photon multileaf collimator (MLC) (Varian Medical Systems, Inc., Palo Alto, CA) for a Varian linear accelerator (linac). Methods: This beam model is divided into an analytical part (two photon and two electron sources) and a Monte Carlo (MC) transport through the MLC. For dose calculation purposes the beam model has been coupled with a macro MC dose calculation algorithm. The commissioning process requires a set of measurements and precalculated MC input. The beam model has been commissioned at a source to surface distance of 70 cm for a Clinac 23EX (Varian Medical Systems, Inc., Palo Alto, CA) and a TrueBeam linac (Varian Medical Systems, Inc., Palo Alto, CA). For validation purposes, measured and calculated depth dose curves and dose profiles are compared for four different MLC shaped electron fields and all available energies. Furthermore, a measured two-dimensional dose distribution for patched segments consisting of three 18 MeV segments, three 12 MeV segments, and a 9 MeV segment is compared with corresponding dose calculations. Finally, measured and calculated two-dimensional dose distributions are compared for a circular segment encompassed with a C-shaped segment. Results: For 15 × 34, 5 × 5, and 2 × 2 cm{sup 2} fields differences between water phantom measurements and calculations using the beam model coupled with the macro MC dose calculation algorithm are generally within 2% of the maximal dose value or 2 mm distance to agreement (DTA) for all electron beam energies. For a more complex MLC pattern, differences between measurements and calculations are generally within 3% of the maximal dose value or 3 mm DTA for all electron beam energies. For the two-dimensional dose comparisons, the differences between calculations and measurements are generally within 2% of the maximal dose value or 2 mm DTA. Conclusions : The results of the dose comparisons suggest that the developed beam model is suitable to accurately reconstruct photon MLC shaped electron beams for a Clinac 23EX and a TrueBeam linac. Hence, in future work the beam model will be utilized to investigate the possibilities of MERT using the photon MLC to shape electron beams.

  1. Time domain analysis of a gyrotron traveling wave amplifier with misaligned electron beam

    SciTech Connect (OSTI)

    Wang, Qiushi, E-mail: qiushiwork@gmail.com; Peng, Shuyuan [Institute of Electronics, Chinese Academy of Sciences, P.O. Box 2652, Beijing 100080 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Luo, Jirun [Institute of Electronics, Chinese Academy of Sciences, P.O. Box 2652, Beijing 100080 (China)

    2014-08-15T23:59:59.000Z

    This article develops a time-domain theory to study the beam-wave interaction in gyrotron traveling wave amplifier (gyro-TWA) with a misaligned electron beam. The effects of beam misalignment on the TE{sub 01} mode gyro-TWA operating at the fundamental are discussed. Numerical results show that the effect of misalignment is less obvious when the input power is larger, and the influences of misalignment on the stable gain and the stable time are basically opposite.

  2. New density estimation methods for charged particle beams with applications to microbunching instability

    SciTech Connect (OSTI)

    Terzic, B.; Bassi, G.

    2011-07-08T23:59:59.000Z

    In this paper we discuss representations of charge particle densities in particle-in-cell simulations, analyze the sources and profiles of the intrinsic numerical noise, and present efficient methods for their removal. We devise two alternative estimation methods for charged particle distribution which represent significant improvement over the Monte Carlo cosine expansion used in the 2D code of Bassi et al. [G. Bassi, J.A. Ellison, K. Heinemann and R. Warnock Phys. Rev. ST Accel. Beams 12 080704 (2009)G. Bassi and B. Terzic, in Proceedings of the 23rd Particle Accelerator Conference, Vancouver, Canada, 2009 (IEEE, Piscataway, NJ, 2009), TH5PFP043], designed to simulate coherent synchrotron radiation (CSR) in charged particle beams. The improvement is achieved by employing an alternative beam density estimation to the Monte Carlo cosine expansion. The representation is first binned onto a finite grid, after which two grid-based methods are employed to approximate particle distributions: (i) truncated fast cosine transform; and (ii) thresholded wavelet transform (TWT). We demonstrate that these alternative methods represent a staggering upgrade over the original Monte Carlo cosine expansion in terms of efficiency, while the TWT approximation also provides an appreciable improvement in accuracy. The improvement in accuracy comes from a judicious removal of the numerical noise enabled by the wavelet formulation. The TWT method is then integrated into the CSR code [G. Bassi, J.A. Ellison, K. Heinemann and R. Warnock Phys. Rev. ST Accel. Beams 12 080704 (2009)], and benchmarked against the original version. We show that the new density estimation method provides a superior performance in terms of efficiency and spatial resolution, thus enabling high-fidelity simulations of CSR effects, including microbunching instability.

  3. Complex modes and new amplification regimes in periodic multi transmission lines interacting with an electron beam

    E-Print Network [OSTI]

    Othman, Mohamed; Capolino, Filippo

    2014-01-01T23:59:59.000Z

    We show the existence of a new regime of operation for travelling wave tubes (TWTs) composed of slow-wave periodic structures that support two or more electromagnetic modes, with at least two synchronized with an electron beam. The interaction between the slow-wave structure and an electron beam is quantified using a multi transmission line approach (MTL) and transfer matrix analysis leading to the identification of modes with complex Bloch wavenumber. In particular, we report a new operation condition for TWTs based on an electron beam synchronous to two modes exhibiting a degeneracy condition near a band edge in a MTL slow-wave periodic structure. We show a phenomenological change in the band structure of periodic TWT where we observe at least two growing modal cooperating solutions as opposed to a uniform MTL interacting with an electron beam where there is strictly only one growing mode solution.

  4. Proceedings of the conference on electron beam melting and refining - state of the art 1994

    SciTech Connect (OSTI)

    Bakish, R. [ed.

    1994-12-31T23:59:59.000Z

    The volume: Proceedings of the Conference on Electron Beam Melting and Refining-State of the Art 1994 covers many aspects of electron beam production, process control, components, and applications. Included were several papers from the defunct Soviet Bloc nations concerning the specifications and uses for their electron beam furnaces. Main topics of the conference were: Electron Beam (EB) Equipment; Safety and Analytical Aspects related to EB Melting; Material Processing with EB; Other Applications for EB; and A Look at EB in the East. EB has many uses, several papers mentioned the recycling of uranium scrap, the casting of heat resistant or corrosion resistant alloys, or the improved microstructure of alloys with the technique.

  5. Precision shape modification of nanodevices with a low-energy electron beam

    DOE Patents [OSTI]

    Zettl, Alex (Kensington, CA); Yuzvinsky, Thomas David (Berkeley, CA); Fennimore, Adam (Berkeley, CA)

    2010-03-09T23:59:59.000Z

    Methods of shape modifying a nanodevice by contacting it with a low-energy focused electron beam are disclosed here. In one embodiment, a nanodevice may be permanently reformed to a different geometry through an application of a deforming force and a low-energy focused electron beam. With the addition of an assist gas, material may be removed from the nanodevice through application of the low-energy focused electron beam. The independent methods of shape modification and material removal may be used either individually or simultaneously. Precision cuts with accuracies as high as 10 nm may be achieved through the use of precision low-energy Scanning Electron Microscope scan beams. These methods may be used in an automated system to produce nanodevices of very precise dimensions. These methods may be used to produce nanodevices of carbon-based, silicon-based, or other compositions by varying the assist gas.

  6. Real-time spatial-phase-locked electron-beam lithography

    E-Print Network [OSTI]

    Zhang, Feng, 1973-

    2005-01-01T23:59:59.000Z

    The ability of electron-beam lithography (EBL) to create sub-10-nm features with arbitrary geometry makes it a critical tool in many important applications in nanoscale science and technology. The conventional EBL system ...

  7. Temescal FC-2000 Electron Beam Evaporator CORAL NAME = EbeamFP

    E-Print Network [OSTI]

    Reif, Rafael

    Temescal FC-2000 Electron Beam Evaporator CORAL NAME = EbeamFP STANDARD OPERATING PROCEDURE immediately, via CORAL. Operating the System 1. Engage the machine in Coral 2. From the Monitor's main Screen

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

    SciTech Connect (OSTI)

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

    2010-06-01T23:59:59.000Z

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

  9. Experimental verification of an ion-induced focus model for the recirculating electron beam injector

    SciTech Connect (OSTI)

    Poukey, J.W.; Mazarakis, M.G. (Sandia National Laboratories, Albuquerque, NM (USA)); Platt, R.C. (Science Applications International, Albuquerque, NM (USA))

    1990-10-22T23:59:59.000Z

    We present a model for the operation of a particular type of electron beam diode used in the Sandia Recirculating Linear Accelerator system. The critical element of the model is ion emission from the anode aperture, which neutralizes enough beam space charge to permit focusing. Recent experimental results are shown which support the model in several respects.

  10. Beam Test of a Large Area nonn Silicon Strip Detector with Fast Binary Readout Electronics

    E-Print Network [OSTI]

    Beam Test of a Large Area n­on­n Silicon Strip Detector with Fast Binary Readout Electronics Y test was carried out for the non­irradiated and the irradiated detector modules. Efficiency, noise occupancy and performance in the edge regions were analyzed using the beam test data. High efficiency

  11. 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.

  12. Development of Electronics for the ATF2 Interaction Point Region Beam Position Monitor

    SciTech Connect (OSTI)

    Kim, Youngim; /Kyungpook Natl. U.; Heo, Ae-young; /Kyungpook Natl. U.; Kim, Eun-San; /Kyungpook Natl. U.; Boogert, Stewart; /Royal Holloway, U. of London; Honda, Yosuke; /KEK, Tsukuba; Tauchi, Toshiaki; /KEK, Tsukuba; Terunuma, Nobuhiro; /KEK, Tsukuba; May, Justin; /SLAC; McCormick, Douglas; /SLAC; Smith, Tonee; /SLAC

    2012-08-14T23:59:59.000Z

    Nanometer resolution beam position monitors have been developed to measure and control beam position stability at the interaction point region of ATF2. The position of the beam has to be measured to within a few nanometers at the interaction point. In order to achieve this performance, electronics for the low-Q IP-BPM was developed. Every component of the electronics have been simulated and checked on the bench and using the ATF2 beam. We will explain each component and define their working range. Then, we will show the performance of the electronics measured with beam signal. ATF2 is a final focus test beam line for ILC in the framework of the ATF international collaboration. The new beam line was constructed to extend the extraction line at ATF, KEK, Japan. The first goal of ATF2 is the acheiving of a 37 nm vertical beam size at focal point (IP). The second goal is to stabilize the beam at the focal point at a few nanometer level for a long period in order to ensure the high luminosity. To achieve these goals a high resolution IP-BPM is essential. In addition for feedback applications a low-Q system is desirable.

  13. 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.

  14. 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.

  15. 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.

  16. Stimulated Raman scattering of laser in a plasma in the presence of a co-propagating electron beam

    SciTech Connect (OSTI)

    Parashar, J. [Department of Physics, Samrat Ashok Technological Institute, Vidisha, Madhya Pradesh 464001 (India)] [Department of Physics, Samrat Ashok Technological Institute, Vidisha, Madhya Pradesh 464001 (India)

    2013-12-15T23:59:59.000Z

    A relativistic electron beam co-propagating with a high power laser in plasma is shown to add to the growth of the stimulated Raman back scattering of the laser. The growth rate is sensitive to phase matching of electron beam with the plasma wave. In the case of phase mismatch, the growth rate drops by an order. The energy spread of the electron beam significantly reduces the effectiveness of the beam on the stimulated Raman process.

  17. Beam conditioning for free electron lasers: Consequences and methods A. Wolski, G. Penn, A. Sessler, and J. Wurtele*

    E-Print Network [OSTI]

    Wurtele, Jonathan

    Beam conditioning for free electron lasers: Consequences and methods A. Wolski, G. Penn, A. Sessler cases [VISA, a soft x-ray free-electron laser (FEL), LCLS, and a ``Greenfield'' FEL] are examined short-wavelength free-electron lasers (FELs) demands electron beams with very small transverse emittance

  18. GeV electron beams from a centimetre-scale accelerator

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    V) electron accelerators are essential to synchrotron radiation facilities and free-electron lasers, and as modules for high-energy particle physics. Radiofrequency-based accelerators are limited to relatively low needed to drive radiation sources, and many kilometres to generate particle energies of interest to high

  19. PROGRESS AND FUTURE DIRECTIONS IN BRIGHTNESS ELECTRON BEAM SOURCES...

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

    be used to produce femto- seconds coherent IR radiation, or femto-seconds X-ray by laser Compton scattering. Photoelectron beam can also be used to drive FEL. 5 ACKNOWLEDGEMENT...

  20. Development of a chemical dosimeter for electron beam food irradiation 

    E-Print Network [OSTI]

    Rivadeneira, Ramiro Geovanny

    2006-08-16T23:59:59.000Z

    A chemical solution composed of paraffin wax, chloroform, and methyl yellow biological indicator was shaped into a solid 3-D apple phantom to determine absorbed dose from e-beams and X-rays. The purpose of this research ...

  1. Overview of Phase Space Manipulations of Relativistic Electron Beams

    SciTech Connect (OSTI)

    Xiang, Dao; /SLAC

    2012-08-31T23:59:59.000Z

    Phase space manipulation is a process to rearrange beam's distribution in 6-D phase space. In this paper, we give an overview of the techniques for tailoring beam distribution in 2D, 4D, and 6D phase space to meet the requirements of various applications. These techniques become a new focus of accelerator physics R&D and very likely these advanced concepts will open up new opportunities in advanced accelerators and the science enabled by them.

  2. Parallel Simulation of Electron Cooling Physics and Beam Transport

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

    all electron cooling simulation activities of the accelerator SciDAC-2 project "ComPASS" that has been extended into 2013. The electron cooling team includes personnel from...

  3. Fidelity of a Time-Resolved Imaging Diagnostic for Electron Beam Profiles

    SciTech Connect (OSTI)

    Frayer, Daniel; Ekdahl, Carl A.; Johnson, Douglas

    2014-10-01T23:59:59.000Z

    An optical tomographic diagnostic instrument has been fielded at the Dual-Axis Radiographic Hydrodynamic Test Facility at Los Alamos National Laboratory. Four optical lines of sight create projections of an image of an electron beam on a Cerenkov target, which are relayed via optical fiber to streak cameras. From these projections, a reconstruction algorithm creates time histories of the beam’s cross section. The instrument was fielded during and after facility commissioning, and tomographic reconstructions reported beam parameters. Results from reconstructions and analysis are noted.

  4. 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,

  5. Common Analysis of the Relativistic Klystron and the Standing-Wave Free-Electron Laser Two-Beam Accelerator

    E-Print Network [OSTI]

    Wurtele, Jonathan S.

    2008-01-01T23:59:59.000Z

    of the standing-wave free-electron laser on the same footingSessler, A.M. , "The Free Electron Laser as a Power SourceNew Version of a Free Electron Laser Two-Beam Accelerator",

  6. Two-Dimensional Simulation Analysis of the Standing-wave Free-electron Laser Two-Beam Accelerator

    E-Print Network [OSTI]

    Wang, C.

    2008-01-01T23:59:59.000Z

    Standing-wave free-electron laser two-beam accelerator,"of a standing-wave free-electron laser," Lawrence Berkeleyof a standing-wave free-electron laser," Lawrence Berkeley

  7. Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures

    E-Print Network [OSTI]

    Alarcon, R; Benson, S V; Bertozzi, W; Boyce, J R; Cowan, R; Douglas, D; Evtushenko, P; Fisher, P; Ihloff, E; Kalantarians, N; Kelleher, A; Kossler, W J; Legg, R; Long, E; Milner, R G; Neil, G R; Ou, L; Schmookler, B; Tennant, C; Tschalaer, C; Williams, G P; Zhang, S

    2013-01-01T23:59:59.000Z

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is ...

  8. Measured Radiation and Background Levels During Transmission of Megawatt Electron Beams Through Millimeter Apertures

    SciTech Connect (OSTI)

    Alarcon, Ricardo [Arizona State University, Glendale, AZ (United States); Balascuta, S. [Arizona State University, Glendale, AZ (United States); Benson, Stephen V. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Bertozzi, William [Massachusetts Institute of Technology, Cambridge, MA (United States); Boyce, James R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Cowan, Ray [Massachusetts Institute of Technology, Cambridge, MA (United States); Douglas, David R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Evtushenko, Pavel [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Fisher, P. [Massachusetts Institute of Technology, Cambridge, MA (United States); Ihloff, Ernest E. [Hampton University, Hampton, VA (United States); Kalantarians, Narbe [Hampton University, Hampton, VA (United States); Kelleher, Aidan Michael [Massachusetts Institute of Technology, Cambridge, MA (United States); Krossler, W. J. [William and Mary College, Williamsburg, VA (United States); Legg, Robert A. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Long, Elena [University of New Hampshire, Durham, NH (United States); Milner, Richard [Massachusetts Institute of Technology, Cambridge, MA (United States); Neil, George R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Ou, Longwu [Massachusetts Institute of Technology, Cambridge, MA (United States); Schmookler, Barack Abraham [Massachusetts Institute of Technology, Cambridge, MA (United States); Tennant, Christopher D. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Tschalar, C. [Massachusetts Institute of Technology, Cambridge, MA (United States); Williams, Gwyn P. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Zhang, Shukui [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2013-11-01T23:59:59.000Z

    We report measurements of photon and neutron radiation levels observed while transmitting a 0.43 MW electron beam through millimeter-sized apertures and during beam-off, but accelerating gradient RF-on, operation. These measurements were conducted at the Free-Electron Laser (FEL) facility of the Jefferson National Accelerator Laboratory (JLab) using a 100 MeV electron beam from an energy-recovery linear accelerator. The beam was directed successively through 6 mm, 4 mm, and 2 mm diameter apertures of length 127 mm in aluminum at a maximum current of 4.3 mA (430 kW beam power). This study was conducted to characterize radiation levels for experiments that need to operate in this environment, such as the proposed DarkLight Experiment. We find that sustained transmission of a 430 kW continuous-wave (CW) beam through a 2 mm aperture is feasible with manageable beam-related backgrounds. We also find that during beam-off, RF-on operation, multipactoring inside the niobium cavities of the accelerator cryomodules is the primary source of ambient radiation when the machine is tuned for 130 MeV operation.

  9. New Density Estimation Methods for Charged Particle Beams With Applications to Microbunching Instability

    SciTech Connect (OSTI)

    Balsa Terzic, Gabriele Bassi

    2011-07-01T23:59:59.000Z

    In this paper we discuss representations of charge particle densities in particle-in-cell (PIC) simulations, analyze the sources and profiles of the intrinsic numerical noise, and present efficient methods for their removal. We devise two alternative estimation methods for charged particle distribution which represent significant improvement over the Monte Carlo cosine expansion used in the 2d code of Bassi, designed to simulate coherent synchrotron radiation (CSR) in charged particle beams. The improvement is achieved by employing an alternative beam density estimation to the Monte Carlo cosine expansion. The representation is first binned onto a finite grid, after which two grid-based methods are employed to approximate particle distributions: (i) truncated fast cosine transform (TFCT); and (ii) thresholded wavelet transform (TWT). We demonstrate that these alternative methods represent a staggering upgrade over the original Monte Carlo cosine expansion in terms of efficiency, while the TWT approximation also provides an appreciable improvement in accuracy. The improvement in accuracy comes from a judicious removal of the numerical noise enabled by the wavelet formulation. The TWT method is then integrated into Bassi's CSR code, and benchmarked against the original version. We show that the new density estimation method provides a superior performance in terms of efficiency and spatial resolution, thus enabling high-fidelity simulations of CSR effects, including microbunching instability.

  10. Atomic-scale electron-beam sculpting of defect-free graphene nanostructures

    E-Print Network [OSTI]

    Dekker, Cees

    Atomic-scale electron-beam sculpting of defect-free graphene nanostructures Bo Song, Grégory F.w.zandbergen@tudelft.nl ABSTRACT. In order to harvest the many promising properties of graphene in (electronic) applications a temperature-dependent self-repair mechanism allowing damage-free atomic-scale sculpting of graphene using

  11. Miniature modified Faraday cup for micro electron beams

    DOE Patents [OSTI]

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

    2008-05-27T23:59:59.000Z

    A micro beam Faraday cup assembly includes a refractory metal layer with an odd number of thin, radially positioned traces in this refractory metal layer. Some of the radially positioned traces are located at the edge of the micro modified Faraday cup body and some of the radially positioned traces are located in the central portion of the micro modified Faraday cup body. Each set of traces is connected to a separate data acquisition channel to form multiple independent diagnostic networks. The data obtained from the two diagnostic networks are combined and inputted into a computed tomography algorithm to reconstruct the beam shape, size, and power density distribution.

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

    SciTech Connect (OSTI)

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

    2014-08-15T23:59:59.000Z

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

  13. Extension of Pierce model to multiple transmission lines interacting with an electron beam

    E-Print Network [OSTI]

    Tamma, Venkata Ananth

    2013-01-01T23:59:59.000Z

    A possible route towards achieving high power microwave devices is through the use of novel slow-wave structures employing multiple coupled transmission lines (MTLs) whose behavior when coupled to electron beams have not been sufficiently explored. We present the extension of the one-dimensional linearized Pierce theory to MTLs coupled to a single electron beam. We develop multiple formalisms to calculate the k-{\\omega} dispersion relation of the system and find that the existence of a growing wave solution is always guaranteed if the electron propagation constant is larger than or equal to the largest propagation constant of the MTL system. We verify our findings with illustrative examples which bring to light unique properties of the system in which growing waves were found to exist within finite bands of the electron propagation constant and discuss possible approach to improve the gain. By treating the beam-MTL interaction as distributed dependent current generators in the MTL, we derive relations charact...

  14. Demonstration of electron beam focusing by a laser-plasma lens

    E-Print Network [OSTI]

    Thaury, Cédric; Döpp, Andreas; Lehe, Remi; Lifschitz, Agustin; Phuoc, Kim Ta; Gautier, Julien; Goddet, Jean-Philippe; Tafzi, Amar; Flacco, Alessandro; Tissandier, Fabien; Sebban, Stéphane; Rousse, Antoine; Malka, Victor

    2014-01-01T23:59:59.000Z

    Laser-plasma technology promises a drastic reduction of the size of high energy electron accelerators. It could make free electron lasers available to a broad scientific community, and push further the limits of electron accelerators for high energy physics. Furthermore the unique femtosecond nature of the source makes it a promising tool for the study of ultra-fast phenomena. However, applications are hindered by the lack of suitable lens to transport this kind of high-current electron beams, mainly due to their divergence. Here we show that this issue can be solved by using a laser-plasma lens, in which the field gradients are five order of magnitude larger than in conventional optics. We demonstrate a reduction of the divergence by nearly a factor of three, which should allow for an efficient coupling of the beam with a conventional beam transport line.

  15. Trigger probe for determining the orientation of the power distribution of an electron beam

    DOE Patents [OSTI]

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

    2007-07-17T23:59:59.000Z

    The present invention relates to a probe for determining the orientation of electron beams being profiled. To accurately time the location of an electron beam, the probe is designed to accept electrons from only a narrowly defined area. The signal produced from the probe is then used as a timing or triggering fiducial for an operably coupled data acquisition system. Such an arrangement eliminates changes in slit geometry, an additional signal feedthrough in the wall of a welding chamber and a second timing or triggering channel on a data acquisition system. As a result, the present invention improves the accuracy of the resulting data by minimizing the adverse effects of current slit triggering methods so as to accurately reconstruct electron or ion beams.

  16. Uranium-contaminated soils: Ultramicrotomy and electron beam analysis

    SciTech Connect (OSTI)

    Buck, E.C.; Dietz, N.L.; Bates, J.K.; Cunnane, J.C.

    1994-04-01T23:59:59.000Z

    Uranium contaminated soils from the Fernald Operation Site, Ohio, have been examined by a combination of optical microscopy, scanning electron microscopy with backscattered electron detection (SEM/BSE), and analytical electron microscopy (AEM). A method is described for preparing of transmission electron microscopy (TEM) thin sections by ultramicrotomy. By using these thin sections, SEM and TEM images can be compared directly. Uranium was found in iron oxides, silicates (soddyite), phosphates (autunites), and fluorite. Little uranium was associated with clays. The distribution of uranium phases was found to be inhomogeneous at the microscopic level.

  17. COMMISSIONING COSY COOLER WITH ELECTRON BEAM AT NOVOSIBIRSK

    E-Print Network [OSTI]

    Kozak, Victor R.

    HV power supply (plus/minus 30 kV) and power supply of the magnetic coils. The electrical power to study nuclear physics in the range of relativistic physics 1-8 Gev/u will require very powerful cooling system of the "cooling" of the antiproton beam for suppression of the internal target influence

  18. OTR measurements and modeling of the electron beam optics at the E-cooling facility

    SciTech Connect (OSTI)

    Warner, A.; Burov, Alexey V.; Carlson, K.; Kazakevich, G.; Nagaitsev, S.; Prost, L.; Sutherland, M.; Tiunov, M.; /Fermilab /Novosibirsk, IYF

    2005-11-01T23:59:59.000Z

    Optics of the electron beam accelerated in the Pelletron, intended for the electron cooling of 8.9 GeV antiprotons in the Fermilab recycler storage ring, has been studied. The beam profile parameters were measured under the accelerating section using Optical Transition Radiation (OTR) monitor. The monitor employs a highly-reflective 2 inch-diameter aluminum OTR-screen with a thickness of 5 {micro}m and a digital CCD camera. The measurements were done in a pulse-signal mode in the beam current range of 0.03-0.8 A and at pulse durations ranging from 1 {micro}s to 4 {micro}s. Differential profiles measured in pulsed mode are compared with results obtained by modeling of the DC beam dynamics from the Pelletron cathode to the OTR monitor. The modeling was done with SAM, ULTRASAM and BEAM programs. An adjustment of the magnetic fields in the lenses of the accelerating section was done in the simulations. The simulated electron beam optics downstream of the accelerating section was in good agreement with the measurements made with pulsed beam.

  19. TRANSVERSE ELECTRON-PROTON TWO-STREAM INSTABILITY IN A BUNCHED BEAM

    SciTech Connect (OSTI)

    Wang, T. F. (Tai-Sen F.); Channell, Paul J.; Macek, R. J. (Robert J.); Davidson, Ronald C.

    2001-01-01T23:59:59.000Z

    For intense proton beams, the focus of recent two-stream instability analyses has been on the transverse instability observed in the Proton Storage Ring (PSR) at Los Alamos National Laboratory. The PSR stores a long proton bunch with a near triangular line density profile for a duration of about one millisecond. The instability is observed as rapidly growing transverse oscillations of the stored beam, usually occuring when the beam intensity reaches 2.5 x 10{sup 13} ppp or higher, causing fast beam loss. Experimental results support the conjecture that the instability in PSR is due to the two-stream interaction between the circulating proton beam and the electrons created in the ring, i.e., the so called e-p instability. However, the understanding of the physics of this instability is usually based on the theory developed for a continuous beam of uniform line density. Although computer simulations have been implemented or are being developed to study the e-p instability in bunched beams, a companion analytical theory still remains to be developed. The present work is an attempt to investigate the transverse e-p instability in a proton bunch using an analytical approach based on the centroid model built on the 'one-pass' interaction between the protons and the electrons. This paper is an analytical investigation of the transverse electron-proton (e-p) two-stream instability in a proton bunch propagating through a stationary electron background. The equations of motion, including the effect of damping, are derived for the centroids of the proton beam and the electron cloud. An approach is developed to solve the coupled linear centroid equations in the time domain describing the e-p instability in proton bunches with nonuniform line densities. Examples are presented for proton line densities corresponding to uniform and parabolic profiles.

  20. Efficiencies of Aloof-Scattered Electron Beam Excitation of Metal and Graphene Plasmons

    E-Print Network [OSTI]

    Ooi, Kelvin J A; Chu, Hong Son; Tan, Dawn T H; Ang, L K

    2015-01-01T23:59:59.000Z

    We assessed the efficiencies of surface plasmon excitation by an aloof-scattered electron beam on metals and graphene. Graphene is shown to exhibit high energy transfer efficiencies at very low electron kinetic energy requirements. We show that the exceptional performance of graphene is due to its unique plasmon dispersion, low electronic density and thin-film structure. The potential applications of these aloof-scattered graphene plasmons are discussed in aspects of coherent radiation.

  1. Hard x-ray or gamma ray laser by a dense electron beam

    SciTech Connect (OSTI)

    Son, S. [18 Caleb Lane, Princeton, New Jersey 08540 (United States); Joon Moon, Sung [8 Benjamin Rush Ln., Princeton, New Jersey 08540 (United States)

    2012-06-15T23:59:59.000Z

    A dense electron beam propagating through a laser undulator can radiate a coherent x-ray or gamma ray. This lasing scheme is studied with the Landau damping theory. The analysis suggests that, with currently available physical parameters, coherent gamma rays of up to 50 keV can be generated. The electron quantum diffraction suppresses the free electron laser action, which limits the maximum radiation.

  2. Separation of beam and electrons in the spallation neutron source H{sup -} ion source

    SciTech Connect (OSTI)

    Whealton, J.H.; Raridon, R.J. [Oak Ridge National Lab., TN (United States); Leung, K.N. [Lawrence Berkeley National Lab., CA (United States)

    1997-12-01T23:59:59.000Z

    The Spallation Neutron Source (SNS) requires an ion source producing an H{sup {minus}} beam with a peak current of 35mA at a 6.2 percent duty factor. For the design of this ion source, extracted electrons must be transported and dumped without adversely affecting the H{sup {minus}} beam optics. Two issues are considered: (1) electron containment transport and controlled removal; and (2) first-order H{sup {minus}} beam steering. For electron containment, various magnetic, geometric and electrode biasing configurations are analyzed. A kinetic description for the negative ions and electrons is employed with self-consistent fields obtained from a steady-state solution to Poisson`s equation. Guiding center electron trajectories are used when the gyroradius is sufficiently small. The magnetic fields used to control the transport of the electrons and the asymmetric sheath produced by the gyrating electrons steer the ion beam. Scenarios for correcting this steering by split acceleration and focusing electrodes will be considered in some detail.

  3. 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.

  4. Investigation of a direction sensitive sapphire detector stack at the 5 GeV electron beam at DESY-II

    E-Print Network [OSTI]

    Karacheban, O; Hempel, M; Henschel, H; Lange, W; Leonard, J L; Levy, I; Lohmann, W; Schuwalow, S

    2015-01-01T23:59:59.000Z

    Extremely radiation hard sensors are needed in particle physics experiments to instrument the region near the beam pipe. Examples are beam halo and beam loss monitoring systems at the Large Hadron Collider, FLASH or XFEL. Artificial diamond sensors are currently widely used as sensors in these systems. In this paper single crystal sapphire sensors are considered as a promising alternative. Industrially grown sapphire wafers are available in large sizes, are of low cost and, like diamond sensors, can be operated without cooling. Here we present results of an irradiation study done with sapphire sensors in a high intensity low energy electron beam. Then, a multichannel direction-sensitive sapphire detector stack is described. It comprises 8 sapphire plates of 1 cm^2 size and 525 micrometer thickness, metallized on both sides, and apposed to form a stack. Each second metal layer is supplied with a bias voltage, and the layers in between are connected to charge-sensitive preamplifiers. The performance of the dete...

  5. Low-temperature Bessel beam trap for single submicrometer aerosol particle studies

    SciTech Connect (OSTI)

    Lu, Jessica W.; Chasovskikh, Egor; Stapfer, David [Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich (Switzerland); Isenor, Merrill; Signorell, Ruth [Laboratory of Physical Chemistry, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich (Switzerland); Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, British Columbia V6T 1Z1 (Canada)

    2014-09-01T23:59:59.000Z

    We report on a new instrument for single aerosol particle studies at low temperatures that combines an optical trap consisting of two counter-propagating Bessel beams (CPBBs) and temperature control down to 223 K (?50?°C). The apparatus is capable of capturing and stably trapping individual submicrometer- to micrometer-sized aerosol particles for up to several hours. First results from studies of hexadecane, dodecane, and water aerosols reveal that we can trap and freeze supercooled droplets ranging in size from ?450 nm to 5500 nm (radius). We have conducted homogeneous and heterogeneous freezing experiments, freezing-melting cycles, and evaporation studies. To our knowledge, this is the first reported observation of the freezing process for levitated single submicrometer-sized droplets in air using optical trapping techniques. These results show that a temperature-controlled CPBB trap is an attractive new method for studying phase transitions of individual submicrometer aerosol particles.

  6. Observation of a single-beam gradient force acoustical trap for elastic particles: acoustical tweezers

    E-Print Network [OSTI]

    Baresch, Diego; Marchiano, Régis

    2014-01-01T23:59:59.000Z

    The ability to manipulate matter precisely is critical for the study and development of a large variety of systems. Optical tweezers are excellent tools to handle particles ranging in size from a few micrometers to hundreds of nanometers but become inefficient and damaging on larger objects. We demonstrate for the first reported time the trapping of elastic particles by the large gradient force of a single acoustical beam in three dimensions. We show that at equal power, acoustical forces overtake by 8 orders of magnitude that of optical ones on macroscopic objects. Acoustical tweezers can push, pull and accurately control both the position of the particle and the forces exerted under damage-free conditions. The large spectrum of frequencies covered by coherent ultrasonic sources will provide a wide variety of manipulation possibilities from macro- to microscopic length scales. We believe our observations improve the prospects for wider use of non-contact manipulation in biology, biophysics, microfluidics and...

  7. Geek-Up: 350,000 Pounds of Paper, 30,000 Particle Beams and 14 Days in Flight

    Broader source: Energy.gov [DOE]

    Did you know that right now, across the globe, particle beams from some 30,000 accelerators are at work doing everything from diagnosing and treating disease to powering industrial processes?

  8. Melt and vapor characteristics in an electron beam evaporator

    SciTech Connect (OSTI)

    Blumenfeld, L.; Fleche, J.L.; Gonella, C. [DCC/DPE/SPEA Centre d`Etudes de Saclay, Gif-sur-Yvette (France)

    1994-12-31T23:59:59.000Z

    We compare the free surface temperatures T{sub s}, calculated by two methods, in cerium or copper evaporation experiments. The first method considers properties of the melt: by an empirical law we take into account turbulent thermal convection, instabilities and craterization of the free surface. The second method considers the vapor flow expansion and connects T{sub s} to the measured terminal parallel temperature and the terminal mean parallel velocity of the vapor jet, by Direct Simulation Monte Carlo calculations including an atom-atom inelastic collision algorithm. The agreement between the two approaches is better for cerium than for copper in the high craterization case. The analysis, from the point of view of the properties of the melt, of the terminal parameters of the vapor jet for the high beam powers shows that T{sub s} and the Knudsen number at the vapor source reach a threshold when the beam power increases.

  9. Time-dependent simulation of prebunched one and two-beam free electron laser

    SciTech Connect (OSTI)

    Mirian, N. S., E-mail: najmeh.mirian@ipm.ir [School of Particle and Accelerator Physics, Institute for Research in Fundamental Sciences (IPM), Post code 19395-5531 Tehran (Iran, Islamic Republic of); Maraghechi, B. [Department of Physics, Amirkabir University of Technology, Post code 15875-4413 Tehran (Iran, Islamic Republic of)] [Department of Physics, Amirkabir University of Technology, Post code 15875-4413 Tehran (Iran, Islamic Republic of)

    2014-04-15T23:59:59.000Z

    A numerical simulation in one-dimension is conducted to study the slippage effects on prebunched free electron laser. A technique for the simulation of time dependent free electron lasers (FEL) to model the slippage effects is introduced, and the slowly varying envelope approximation in both z and t is used to illustrate the temporal behaviour in the prebunched FEL. Slippage effect on prebunched two-beam FEL is compared with the one-beam modeling. The evaluation of the radiation pulse energy, thermal and phase distribution, and radiation pulse shape in one-beam and two-beam modeling is studied. It was shown that the performance is considerably undermined when the slippage time is comparable to the pulse duration. However, prebunching reduces the slippage. Prebunching also leads to the radiation pulse with a single smooth spike.

  10. Improvement of extraction efficiency from a compact synchrotron for proton beam therapy by applying particle tracking analysis

    SciTech Connect (OSTI)

    Ebina, Futaro; Umezawa, Masumi; Hiramoto, Kazuo [Hitachi Research Laboratory, Hitachi, Ltd. 2-1, Omika-cho 7-chome, Hitachi-shi, Ibaraki-ken, 319-1221 (Japan)

    2013-04-19T23:59:59.000Z

    Various types of synchrotrons are used for particle beam therapy. In particle beam therapy, especially in proton beam therapy, downsizing of the accelerator system is a major concern. A compact synchrotron dedicated for proton beam therapy is presented. The synchrotron is horizontally weakly focusing and consists of 4 H-type zerogradient dipole magnets and 4 quadrupole magnets. The circumference of the ring is a little shorter than 18 m, and the energies are up to 230MeV. Beam extraction from the synchrotron is performed by RF-driven slow extraction technology. Two sextupole magnets set in adjacent straight sections form a horizontal separatrix which is fixed during the beam extraction. Horizontal RF voltage excites betatron oscillation of the circulating beam, and protons exceeding the separatrix are extracted by an electrostatic deflector and a horizontal septum dipole magnet. To achieve adequately high extraction efficiency, the relationship between the extraction efficiency and the horizontal chromaticity of the ring is analyzed by particle tracking simulation. The horizontal chromaticity with maximum extraction efficiency is half of the theoretical value because of the distortion of the horizontal separatrix for the extraction. With this chromaticity, the spiral-step of the extracted particle is independent of the momentum deviation of the particle, and the separatrix across the electrostatic septum electrodes is superpositioned.

  11. Uranium-contaminated soils: Ultramicrotomy and electron beam analysis

    SciTech Connect (OSTI)

    Buck, E.C.; Dietz, N.L.; Bates, J.K.; Cunnane, J.C.

    1994-02-01T23:59:59.000Z

    Uranium-contaminated soils from the U.S. Department of Energy (DOE) Fernald Site, Ohio, have been examined by a combination of scanning electron microscopy with backscattered electron imaging (SEM/BSE) and analytical electron microscopy (AEM). The inhomogeneous distribution of particulate uranium phases in the soil required the development of a method for using ultramicrotomy to prepare transmission electron microscopy (TEM) thin sections of the SEM mounts. A water-miscible resin was selected that allowed comparison between SEM and TEM images, permitting representative sampling of the soil. Uranium was found in iron oxides, silicates (soddyite), phosphates (autunites), and fluorite (UO{sub 2}). No uranium was detected in association with phyllosilicates in the soil.

  12. Growth of silicon-on-insulator films using a line-source electron beam

    SciTech Connect (OSTI)

    Knapp, J.A.; Picraux, S.T.

    1982-01-01T23:59:59.000Z

    A swept line-source electron beam has been used to study unseeded Si-on-insulator crystallization at beam scan speeds of 150 to 1500 cm/s. For a particular sample configuration a maximum linear crystallization velocity of approx. 350 cm/s was observed. At higher sweep speeds, competing nucleation occurred at intervals across the film. Both the limit in crystallization velocity and the intervals between nucleation are tentatively explained by a simple model.

  13. Electron beam accelerator: A new tool for environmental preservation in Malaysia

    SciTech Connect (OSTI)

    Hashim, Siti Aiasah; Bakar, Khomsaton Abu; Othman, Mohd Nahar [Malaysian Nuclear Agency, Bangi, 43000, Kajang Selangor (Malaysia)

    2012-09-26T23:59:59.000Z

    Electron beam accelerators are widely used for industrial applications such as surface curing, crosslinking of wires and cables and sterilization/ decontamination of pharmaceutical products. The energy of the electron beam determines the type of applications. This is due to the penetration power of the electron that is limited by the energy. In the last decade, more work has been carried out to utilize the energetic electron for remediation of environmental pollution. For this purposes, 1 MeV electron beam accelerator is sufficient to treat wastewater from textile industry and flue gases from fossil fuel combustions. In Nuclear Malaysia, a variable energy Cockroft Walton type accelerator has been utilized to initiate investigations in these two areas. An electron beam flue gas treatment test rig was built to treat emission from diesel combustion, where it was found that using EB parameters of 1MeV and 12mA can successfully remove at least 80% of nitric oxide in the emission. Wastewater from textile industries was treated using combination of biological treatment and EB. The initial findings indicated that the quality of water had improved based on the COD{sub Cr}, BOD{sub 5} indicators.

  14. 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.

  15. 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.

  16. Apparatus for maintaining aligment of a shrinking weld joint in an electron-beam welding operation

    DOE Patents [OSTI]

    Trent, J.B.; Murphy, J.L.

    1980-01-03T23:59:59.000Z

    The invention is directed to an apparatus for automatically maintaining a shrinking weld joint in alignement with an electron beam during an electron-beam multipass-welding operation. The apparatus utilizes a bias means for continually urging a workpiece-supporting face plate away from a carriage mounted base that rotatably supports the face plate. The extent of displacement of the face plate away from the base in indicative of the shrinkage occuring in the weld joint area. This displacement is measured and is used to move the base on the carriage a distance equal to one-half the displacement for aligning the weld joint with the electron beam during each welding pass.

  17. Apparatus for maintaining alignment of a shrinking weld joint in an electron-beam welding operation

    DOE Patents [OSTI]

    Trent, Jett B. (Knoxville, TN); Murphy, Jimmy L. (Oak Ridge, TN)

    1981-01-01T23:59:59.000Z

    The present invention is directed to an apparatus for automatically maintaining a shrinking weld joint in alignment with an electron beam during an electron-beam multipass-welding operation. The apparatus utilizes a biasing device for continually urging a workpiece-supporting face plate away from a carriage mounted base that rotatably supports the face plate. The extent of displacement of the face plate away from the base is indicative of the shrinkage occuring in the weld joint area. This displacement is measured and is used to move the base on the carriage a distance equal to one-half the displacement for aligning the weld joint with the electron beam during each welding pass.

  18. Efficiency enhancement of a two-beam free-electron laser

    SciTech Connect (OSTI)

    Rouhani, M. H.; Maraghechi, B.; Saberi, H. [Department of Physics, Amirkabir University of Technology, 15875-4413 Tehran (Iran, Islamic Republic of)

    2009-12-15T23:59:59.000Z

    A local and nonlinear simulation of two-beam and tapered free-electron laser (FEL) is presented self-consistently. The slippage of the electromagnetic wave with respect to the electron beam is ignored and the relativistic electron beams are assumed to be cold. The fundamental resonance and the third harmonic radiation of the beam with lower energy are considered, in which the third harmonic is at the fundamental resonance of the beam with higher energy. The wiggler field is set to decrease linearly when the radiation of the third harmonic saturates. The optimum starting point of tapering and the slope of the reduction in the amplitude of wiggler are found by successive run of the code. Using the slowly varying envelope approximation, a set of nonlinear equations is derived which describes this system. These equations are solved numerically by the Runge-Kutta method. This method can be used to improve the efficiency of the two-beam FEL in the extreme ultraviolet and x-ray regions of spectrum.

  19. High-pressure arcs as vacuum-atmosphere interface and plasma lens for nonvacuum electron beam welding machines, electron beam melting, and nonvacuum ion material modification

    SciTech Connect (OSTI)

    Hershcovitch, A. [AGS Department, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)] [AGS Department, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)

    1995-11-01T23:59:59.000Z

    Atmospheric pressure plasmas can be used to provide a vacuum-atmosphere interface 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. Included in the article are a theoretical framework, experimental results, and possible applications for this novel interface. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  20. 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.

  1. Electronic Surface Structures of Coal and Mineral Particles

    SciTech Connect (OSTI)

    M.K. Mazumder; D.A. Lindquist; K.B. Tennal; Steve Trigwell; Steve Farmer; Albert Nutsukpul; Alex Biris

    2001-04-01T23:59:59.000Z

    Surface science studies related to tribocharging and charge separation studies were performed on electrostatic beneficiation of coal. In contrast to other cleaning methods, electrostatic beneficiation is a dry cleaning process requiring no water or subsequent drying. Despite these advantages, there is still uncertainty in implementing large scale commercial electrostatic beneficiation of coal. The electronic surface states of coal macerals and minerals are difficult to describe due to their chemical complexity and variability [1]. The efficiency in separation of mineral particles from organic macerals depends upon these surface states. Therefore, to further understand and determine a reason for the bipolar charging observed in coal separation, surface analysis studies using Ultra-violet Photoelectron Spectroscopy (UPS) and X-ray Photoelectron Spectroscopy (XPS) were performed on coal samples and several materials that are used or considered for use in tribocharging. Electrostatic charging is a surface phenomenon, so the electronic surface states of the particles, which are influenced by the environmental conditions, determine both polarity and magnitude of tribocharging. UPS was used to measure the work function of the materials as typically used in ambient air. XPS was used to determine the surface chemistry in the form of contamination and degree of oxidation under the same environmental conditions. Mineral bearing coals are those amenable to electrostatic beneficiation. Three types of coal, Illinois No. 6, Pittsburgh No. 8, and Kentucky No. 9 were investigated in this study. Pulverized coal powder was tribocharged against copper. Pyritic and other ashes forming minerals in coal powders should charge with a negative polarity from triboelectrification, and organic macerals should acquire positive charge, according to the relative differences in the surface work functions between the material being charged and the charging medium. Different types of minerals exhibit different magnitudes of negative charge and some may also charge positively against copper [2]. Only the mineral sulfur fraction of the total sulfur content is accessible by the electrostatic method since organic sulfur is covalently bound with carbon in macerals. The sizes of mineral constituents in coal range from about 0.1 to 100 {micro}m, but pyrites in many coals are on the lower end of this scale necessitating fine grinding for their liberation and separation. A ready explanation for coal powder macerals to charge positively by triboelectrification is found in the large numbers of surface carbon free radicals available to release electrons to form aromatic carbocations. There is evidence that these cationic charges are delocalized over several atoms [3]. Only perhaps one in one hundred thousand of the surface atoms is charged during triboelectrification [4], making it difficult to predict charging levels since the data depends upon the surface chemical species involved in charging. Based on the high electron affinity of oxygen atoms, oxidation is expected to decrease the extent of a coal particle to charge positively. Also, ion transfer may contribute to the increasingly negative charging character of oxidized coal carbons. A variety of oxidized surface functional groups may influence charge properties. For example, carboxylic acid functions can lose protons to form carboxylate anions. The samples of coal investigated in this study showed differing degrees of beneficiation, consistent with a more extensively oxidized Illinois No. 6 coal sample relative to that of Pittsburgh No. 8. Even though oxygen in air is deleterious to coal stored prior to beneficiation, other gases might favorably influence charge properties. To this end, coal exposed to vapors of acetone, ammonia, and sulfur dioxide also were beneficiated and analyzed in this study.

  2. Polarimetry of the polarized hydrogen deuteride HDice target under an electron beam

    SciTech Connect (OSTI)

    Laine, Vivien E. [Universite Blaise Pascal

    2013-10-01T23:59:59.000Z

    The study of the nucleon structure has been a major research focus in fundamental physics in the past decades and still is the main research line of the Thomas Jefferson National Accelerator Facility (Jefferson Lab). For this purpose and to obtain statistically meaningful results, having both a polarized beam and a highly efficient polarized target is essential. For the target, this means high polarization and high relative density of polarized material. A Hydrogen Deuteride (HD) target that presents both such characteristics has been developed first at Brookhaven National Lab (BNL) and brought to the Hall B of Jefferson Lab in 2008. The HD target has been shown to work successfully under a high intensity photon beam (BNL and Jefferson Lab). However, it remained to be seen if the target could stand an electron beam of reasonably high current (nA). In this perspective, the target was tested for the first time in its frozen spin mode under an electron beam at Jefferson Lab in 2012 during the g14 experiment. This dissertation presents the principles and usage procedures of this HD target. The polarimetry of this target with Nuclear Magnetic Resonance (NMR) during the electron beam tests is also discussed. In addition, this dissertation also describes another way to perform target polarimetry with the elastic scattering of electrons off a polarized target by using data taken on helium-3 during the E97-110 experiment that occurred in Jefferson Lab's Hall A in 2003.

  3. Study of dust particle charging in weakly ionized inert gases taking into account the nonlocality of the electron energy distribution function

    SciTech Connect (OSTI)

    Filippov, A. V., E-mail: fav@triniti.ru; Dyatko, N. A. [Troitsk Institute for Innovation and Fusion Research, Russian State Research Center (Russian Federation); Kostenko, A. S. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2014-11-15T23:59:59.000Z

    The charging of dust particles in weakly ionized inert gases at atmospheric pressure has been investigated. The conditions under which the gas is ionized by an external source, a beam of fast electrons, are considered. The electron energy distribution function in argon, krypton, and xenon has been calculated for three rates of gas ionization by fast electrons: 10{sup 13}, 10{sup 14}, and 10{sup 15} cm{sup ?1}. A model of dust particle charging with allowance for the nonlocal formation of the electron energy distribution function in the region of strong plasma quasi-neutrality violation around the dust particle is described. The nonlocality is taken into account in an approximation where the distribution function is a function of only the total electron energy. Comparative calculations of the dust particle charge with and without allowance for the nonlocality of the electron energy distribution function have been performed. Allowance for the nonlocality is shown to lead to a noticeable increase in the dust particle charge due to the influence of the group of hot electrons from the tail of the distribution function. It has been established that the screening constant virtually coincides with the smallest screening constant determined according to the asymptotic theory of screening with the electron transport and recombination coefficients in an unperturbed plasma.

  4. Modeling of the recycling particle flux and electron particle transport in the DIII-D tokamak

    SciTech Connect (OSTI)

    Baker, D.R.; Jackson, G.L. [General Atomics, San Diego, CA (United States); Maingi, R. [Oak Ridge Associated Universities, Inc., TN (United States); Owen, L.W. [Oak Ridge National Lab., TN (United States); Porter, G.D. [Lawrence Livermore National Lab., CA (United States)

    1996-10-01T23:59:59.000Z

    One of the most difficult aspects of performing an equilibrium particle transport analysis in a diverted tokamak is the determination of the particle flux which enters the plasma after recycling from the divertor plasma, the divertor target plates or the vessel wall. An approach which has been utilized in the past is to model the edge, scrape-off layer (SOL), and divertor plasma to match measured plasma parameters and then use a neutral transport code to obtain an edge recycling flux while trying to match the measured divertor D(x emissivity. Previous simulations were constrained by electron density (n{sub e}) and temperature (T{sub e}), ion temperature (T{sub i}) data at the outer midplane, divertor heat flux from infrared television cameras, and n{sub e}, T{sub e} and particle flux at the target from fixed Langmuir probes, along with the divertor D{sub {alpha}} emissivity. In this paper, we present results of core fueling calculations from the 2-D modeling for ELM-free discharges, constrained by data from the new divertor diagnostics. In addition, we present a simple technique for estimating the recycling flux just after the L-H transition and demonstrate how this technique is supported by the detailed modeling. We will show the effect which inaccuracies in the recycling flux have on the calculated particle flux in the plasma core. For some specific density profiles, it is possible to separate the convective flux from the conductive flux. The diffusion coefficients obtained show a sharp decrease near a normalized radius of 0.9 indicating the presence of a transport barrier.

  5. Electron beams in material testing for fusion reactors

    SciTech Connect (OSTI)

    Ganley, J.T.; McDonald, J.M.; Youchison, D.L. [Sandia National Laboratories, Albuquerque, NM (United States)

    1995-12-31T23:59:59.000Z

    The Plasma Material Test Facility at Sandia National Laboratory is currently involved in a multi-year program of thermally testing materials and high heat flux components for eventual use in fusion reactors. The major test system in the facility is the EB-1200 System, which uses two EH600S Von Ardenne electron guns to provide up to 1.2 MW of heating for large material samples and components. In this paper, the advantages of using electron guns for this type of testing will be discussed. Gun performance characteristics will be presented, as well as electronic techniques used to provide the rapidly varying power levels and complex scan patterns required for complicated targets. Diagnostic capabilities of importance to the experimental program will also be discussed.

  6. 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.

  7. Progress toward uranium scrap recycling via electron beam cold hearth refining

    SciTech Connect (OSTI)

    McKoon, R.H.

    1994-12-15T23:59:59.000Z

    A 250 kW electron beam cold hearth refining (EBCHR) melt furnace at Lawrence Livermore National Laboratory (LLNL) has been in operation for over a year producing 5.5 in.-diameter ingots of various uranium alloys. Production of in-specification uranium-6%-niobium (U-6Nb) alloy ingots has been demonstrated using Virgin feedstock. A vibratory scrap feeder has been installed on the system and the ability to recycle chopped U-6Nb scrap has been established. A preliminary comparison of vacuum arc remelted (VAR) and electron beam (EB) melted product is presented.

  8. Progress toward uranium scrap recycling via electron beam cold hearth refining

    SciTech Connect (OSTI)

    McKoon, R.H. [Lawrence Livermore National Lab., CA (United States)

    1994-12-31T23:59:59.000Z

    A 250 kW electron beam cold hearth refining (EBCHR) melt furnace at Lawrence Livermore National Laboratory (LLNL) has been in operation for over a year producing 5.5 in.-diameter ingots of various uranium alloys. Production of in-specification uranium 6% niobium (U-6Nb) alloy ingots has been demonstrated using virgin feedstock. A vibratory scrap feeder has been installed on the system and the ability to recycle chopped U-6Nb scrap has been established. A preliminary comparison of vacuum arc remelted (VAR) and electron beam (EB) melted product is presented.

  9. Electron beam weld development on a Filter Pack Assembly. Final report

    SciTech Connect (OSTI)

    Dereskiewicz, J.P.

    1994-06-01T23:59:59.000Z

    A continuous electron beam welding procedure was developed to replace the manual gas tungsten arc welding procedure on the Filter Pack Assembly. A statistical study was used to evaluate the feasibility of electron beam welding 6061-T6 aluminum covers to A356 cast weldments throughout the joint tolerance range specified on product drawings. Peak temperature exposures were not high enough to degrade the heat sensitive electrical components inside the cast weldment. Actual weldments with alodine coating on the weld joint area were successfully cleaned using a nonmetallic fiberglass brush cleaning method.

  10. Progresses in the Studies of Adiabatic Splitting of Charged Particles Beams by Crossing Nonlinear Resonances

    E-Print Network [OSTI]

    Franchi, A; Giovannozzi, M

    2009-01-01T23:59:59.000Z

    The multi-turn extraction from a circular particle accelerator is performed by trapping the beam inside stable islands of the horizontal phase space. In general, by crossing a resonance of order n, n+1 beamlets are created whenever the resonance is stable, whereas if the resonance is unstable the beam is split in n parts. Islands are generated by non-linear magnetic fields, whereas the trapping is realized by means of a given tune variation so to cross adiabatically a resonance. Experiments at the CERN Proton Synchrotron carried out in 2007 gave the evidence of protons trapped in stable islands while crossing the one-third and one-fifth resonances. Dedicated experiments were also carried out to study the trapping process and its reversibility properties. The results of these measurement campaigns are presented and discussed in this paper.

  11. Laser or charged-particle-beam fusion reactor with direct electric generation by magnetic flux compression

    DOE Patents [OSTI]

    Lasche, G.P.

    1987-02-20T23:59:59.000Z

    A high-power-density-laser or charged-particle-beam fusion reactor system maximizes the directed kinetic energy imparted to a large mass of liquid lithium by a centrally located fusion target. A fusion target is embedded in a large mass of lithium, of sufficient radius to act as a tritium breeding blanket, and provided with ports for the access of beam energy to implode the target. The directed kinetic energy is converted directly to electricity with high efficiency by work done against a pulsed magnetic field applied exterior to the lithium. Because the system maximizes the blanket thickness per unit volume of lithium, neutron-induced radioactivities in the reaction chamber wall are several orders of magnitude less than is typical of other fusion reactor systems. 25 figs.

  12. Laser or charged-particle-beam fusion reactor with direct electric generation by magnetic flux compression

    DOE Patents [OSTI]

    Lasche, George P. (Arlington, VA)

    1988-01-01T23:59:59.000Z

    A high-power-density laser or charged-particle-beam fusion reactor system maximizes the directed kinetic energy imparted to a large mass of liquid lithium by a centrally located fusion target. A fusion target is embedded in a large mass of lithium, of sufficient radius to act as a tritium breeding blanket, and provided with ports for the access of beam energy to implode the target. The directed kinetic energy is converted directly to electricity with high efficiency by work done against a pulsed magnetic field applied exterior to the lithium. Because the system maximizes the blanket thickness per unit volume of lithium, neutron-induced radioactivities in the reaction chamber wall are several orders of magnitude less than is typical of other fusion reactor systems.

  13. Beam dynamics performances and applications of a low-energy electron-beam magnetic bunch compressor

    E-Print Network [OSTI]

    Prokop, C R; Carlsten, B E; Church, M

    2013-01-01T23:59:59.000Z

    Many front-end applications of electron linear accelerators rely on the production of temporally-compressed bunches. The shortening of electron bunches is often realized with magnetic bunch compressors located in high-energy sections of accelerators. Magnetic compression is subject to collective effects including space charge and self interaction via coherent synchrotron radiation. In this paper we explore the application of magnetic compression to low-energy ($\\sim 40$ MeV), high-charge (nC) electron bunches with low normalized transverse emittances ($< 5$ $\\mu$m).

  14. Study of beam transverse properties of a thermionic electron gun for application to a compact THz free electron laser

    SciTech Connect (OSTI)

    Hu, Tongning, E-mail: TongningHu@hust.edu.cn, E-mail: yjpei@ustc.edu.cn; Qin, Bin; Tan, Ping; Chen, Qushan; Yang, Lei [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Pei, Yuanji, E-mail: TongningHu@hust.edu.cn, E-mail: yjpei@ustc.edu.cn; Li, Ji [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China)

    2014-10-15T23:59:59.000Z

    A novel thermionic electron gun adopted for use in a high power THz free electron laser (FEL) is proposed in this paper. By optimization of the structural and radiofrequency (RF) parameters, the physical design of the gun is performed using dynamic calculations. Velocity bunching is used to minimize the bunch's energy spread, and the dynamic calculation results indicate that high quality beams can be provided. The transverse properties of the beams generated by the gun are also analyzed. The novel RF focusing effects of the resonance cavity are investigated precisely and are used to establish emittance compensation, which enables the injector length to be reduced. In addition, the causes of the extrema of the beam radius and the normalized transverse emittance are analyzed and interpreted, respectively, and slice simulations are performed to illustrate how the RF focusing varies along the bunch length and to determine the effects of that variation on the emittance compensation. Finally, by observation of the variations of the beam properties in the drift tube behind the electron gun, prospective assembly scenarios for the complete THz-FEL injector are discussed, and a joint-debugging process for the injector is implemented.

  15. Feasibility of Diffraction Radiation for a Non-invasive Diagnostics of the SLAC Electron Beam

    SciTech Connect (OSTI)

    Naumenko, G.; Potylitsyn, A.; /Tomsk Polytechnic U.; Araki, S.; Aryshev, A.; Hayano, H.; Karataev, P.; Muto, T.; Urakawa, J.; /KEK, Tsukuba; Ross, M.; /SLAC; Cline, D.; Fukui, Y.; /UCLA; Hamatsu, R.; /Tokyo Metropolitan U.

    2006-05-16T23:59:59.000Z

    The development of the non-invasive bunch size diagnostics based on the diffraction radiation is now in progress in frame of TPU-KEK-SLAC collaboration. The experimental test of a transverse beam size measurement was performed successful on the KEK-ATF extracted electron beam. However many difficulties emerge if we going from the one GeV electron energy to the several tenth GeV electron beams. The extremely high Lorenz-factor value gives rise to the some problems, such as large contribution of a radiation from an accelerator construction elements in submillimeter wavelength region, extremely pre-wave zone effect even in the optical range, exceeding of the electron beam divergence over the diffraction radiation cone, and so on. More over, the sensitivity of the method based on the optical diffraction radiation from flat slit target decrease catastrophic when an electron energy increase up to several tenth GeV. We suggest the new method based on the phase shift on the slit target, consisting on the two semi-planes which are turned at a some angle one to other (crossed target technique) and present here the results of experimental test of this technique. Also we discuss the origins of indicated difficulties and suggest the ways of these problems solution.

  16. 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.

  17. 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...

  18. Energetic Electrons Accelerated in Solar Particle Events Space Sciences Laboratory, University of Berkeley, CA 94720

    E-Print Network [OSTI]

    California at Berkeley, University of

    , University of Berkeley, CA 94720 Abstract. New measurements of energetic solar electrons from the WIND and ACE/WIND should provide new insights into the origins of energetic solar particles. INTRODUCTIONEnergetic Electrons Accelerated in Solar Particle Events R. P. Lin Space Sciences Laboratory

  19. 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

  20. 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.

  1. Prospects for titanium alloy comparison control by electron beam scan frequency manipulation

    SciTech Connect (OSTI)

    Powell, A.; Pal, U. [Massachusetts Institute of Technology, Cambridge, MA (United States); Avyle, J.V.D.; Damkroger, B. [Sandia National Labs., Albuquerque, NM (United States)

    1996-12-31T23:59:59.000Z

    Using mathematical modelling, the authors evaluate the prospects for using beam spot size and scan frequency to control titanium-aluminum alloy composition in electron beam melting and refining. Composition control is evaluated in terms of attainable steady-state extremes of composition, and the time scales required to change hearth and mold composition between those extremes. Mathematical models predict spot size-evaporation and frequency-evaporation relationships by simulating heat transfer in the surface of the melt, and predict overall composition change using simplifying assumptions about the fluid flow field in a melting hearth. Corroborating experiments were run on the electron beam furnace at Sandia National Laboratories in order to verify predicted relationships between frequency and evaporation and to calculate activity coefficients of aluminum and vanadium in titanium.

  2. Study of the TESLA preaccelerator for the polarised electron beam Aline Curtoni, Marcel Jablonka,

    E-Print Network [OSTI]

    Study of the TESLA preaccelerator for the polarised electron beam Aline Curtoni, Marcel Jablonka, CEA, DSM/DAPNIA, Saclay, France Abstract In the mainframe of the TESLA Technical Design Report a study assumed. Figure 1 : Schematic of the TESLA injector complex. This report deals with the bottom injector

  3. Acceleration of positrons by a relativistic electron beam in the presence of quantum effects

    SciTech Connect (OSTI)

    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); Aki, H.; Khorashadizadeh, S. M. [Physics Department, Birjand University, Birjand (Iran, Islamic Republic of)] [Physics Department, Birjand University, Birjand (Iran, Islamic Republic of)

    2013-09-15T23:59:59.000Z

    Using the quantum magnetohydrodynamic model and obtaining the dispersion relation of the Cherenkov and cyclotron waves, the acceleration of positrons by a relativistic electron beam is investigated. The Cherenkov and cyclotron acceleration mechanisms of positrons are compared together. It is shown that growth rate and, therefore, the acceleration of positrons can be increased in the presence of quantum effects.

  4. Ice-assisted electron beam lithography of graphene Jules A Gardener1

    E-Print Network [OSTI]

    1 Ice-assisted electron beam lithography of graphene Jules A Gardener1 and Jene A Golovchenko1 with a thin ice layer. The irradiated ice plays a crucial role in the process by providing activated species that locally remove graphene from a silicon dioxide substrate. After patterning the graphene, the ice resist

  5. Klystron Instability of a Relativistic Electron Beam in a Bunch Compressor

    E-Print Network [OSTI]

    Klystron Instability of a Relativistic Electron Beam in a Bunch Compressor E.L. Saldina , E passing a magnetic bunch compressor. Analytical expressions are derived for the small-signal gain to Nuclear Instruments and Methods #12;1 Introduction Magnetic bunch compressors are designed to obtain short

  6. Electron beam technologies in Poland state of the art and possibilities of development

    SciTech Connect (OSTI)

    Wojcicki, S. [Institute of Vacuum Technology, Warszawa (Poland)

    1994-12-31T23:59:59.000Z

    The recent state of high energy electron beam /EB/ used for metals melting and welding in Poland has been presented. Some typical construction of EB furnaces and EB welding machines designed and constructed in Institute of Vacuum Technology in Warsaw are shown. The examples of their application has also been described.

  7. An Electron Beam Method for Creating Combina-torial Libraries: Application to Next Generation

    E-Print Network [OSTI]

    Wadley, Haydn

    , VA 22903 U.S.A. The next generation of thermal barriers coating (TBC) systems used on turbine engines8-1 An Electron Beam Method for Creating Combina- torial Libraries: Application to Next Generation. The underlying bond coat layers should have substantially improved oxidation resistance and increased high

  8. 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.

  9. New Measurements of the Transverse Beam Asymmetry for Elastic Electron Scattering from Selected Nuclei

    E-Print Network [OSTI]

    Beck, A.

    We have measured the beam-normal single-spin asymmetry A[subscript n] in the elastic scattering of 1–3 GeV transversely polarized electrons from [superscript 1]H and for the first time from [superscript 4]He, [superscript ...

  10. 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.

  11. Beam Test of a Large Area nonn Silicon Strip Detector with Fast Binary Readout Electronics

    E-Print Network [OSTI]

    Beam Test of a Large Area n­on­n Silicon Strip Detector with Fast Binary Readout Electronics Y­sided detector for the readout, its fabrication is similar to a double­sided device, because the backside, which

  12. Analysis of multicomponent evaporation in electron beam melting and refining of titanium alloys

    SciTech Connect (OSTI)

    Powell, A.; Szekely, J.; Pal, U. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering; Avyle, J. van den; Damkroger, B. [Sandia National Labs., Albuquerque, NM (United States). Materials Processing Dept.

    1997-12-01T23:59:59.000Z

    Experimental evidence and a mathematical model are presented to evaluate the effect of beam-scan frequency on composition change in electron-beam melting of titanium alloys. Experiments characterized the evaporation rate of commercially pure (CP) titanium and vapor composition over titanium alloy with up to 6 wt pct aluminum and 4.5 wt pct vanadium, as a function of beam power, scan frequency, and background pressure. These data and thermal mapping of the hearth melt surface are used to estimate activity coefficients of aluminum and vanadium in the hearth. The model describes transient heat transfer in the surface of the melt and provides a means of estimating enhancement of pure titanium evaporation and change in final aluminum composition due to local heating at moderate beam-scan frequencies.

  13. The ReA electron-beam ion trap charge breeder for reacceleration of rare isotopes

    SciTech Connect (OSTI)

    Lapierre, A.; Schwarz, S.; Kittimanapun, K.; Fogleman, J.; Krause, S.; Nash, S.; Rencsok, R.; Tobos, L.; Perdikakis, G.; Portillo, M.; Rodriguez, J. A.; Wittmer, W.; Wu, X.; Bollen, G.; Leitner, D.; Syphers, M. [National Superconducting Cyclotron Laboratory (NSCL), Michigan State University (MSU), 640 South Shaw Lane, East Lansing, MI 48824 (United States); Collaboration: ReA Team

    2013-04-19T23:59:59.000Z

    ReA is a post-accelerator at the National Superconducting Cyclotron Laboratory at Michigan State University. ReA is designed to reaccelerate rare isotopes to energies of a few MeV/u following production by projectile fragmentation and thermalization in a gas cell. The facility consists of four main components: an electron-beam ion trap (EBIT) charge breeder, an achromatic charge-over-mass (Q/A) separator, a radio-frequency quadrupole accelerator, and a superconducting radio-frequency linear accelerator. The EBIT charge breeder was specifically designed to efficiently capture continuous beams of singly charged ions injected at low energy (<60 keV), charge breed in less than 50 ms, and extract highly charged ions to the Q/A separator for charge-state selection and reacceleration through the accelerator structures. The use of highly charged ions to reach high beam energies is a key aspect that makes ReA a compact and cost-efficient post-accelerator. The EBIT is characterized by a high-current electron gun, a long multi-electrode trap structure and a dual magnet to provide both the high electron-beam current density necessary for fast charge breeding of short-lived isotopes as well as the high capture probability of injected beams. This paper presents an overview and the status of the ReA EBIT, which has extracted for reacceleration tests stable {sup 20}Ne{sup 8+} ion beams produced from injected gas and more recently {sup 39}K{sup 16+} beams by injecting stable {sup 39,41}K{sup +} ions from an external ion source.

  14. Lasers, Electron Beams and New Years Resolutions | Department of Energy

    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 SchoolIn12electron 9 5 -

  15. Design and characterization of electron beam focusing for X-ray generation in novel medical imaging architecture

    SciTech Connect (OSTI)

    Bogdan Neculaes, V., E-mail: neculaes@research.ge.com; Zou, Yun; Zavodszky, Peter; Inzinna, Louis; Zhang, Xi; Conway, Kenneth; Caiafa, Antonio; Frutschy, Kristopher; Waters, William; De Man, Bruno [GE Global Research, Niskayuna, New York 12309 (United States)] [GE Global Research, Niskayuna, New York 12309 (United States)

    2014-05-15T23:59:59.000Z

    A novel electron beam focusing scheme for medical X-ray sources is described in this paper. Most vacuum based medical X-ray sources today employ a tungsten filament operated in temperature limited regime, with electrostatic focusing tabs for limited range beam optics. This paper presents the electron beam optics designed for the first distributed X-ray source in the world for Computed Tomography (CT) applications. This distributed source includes 32 electron beamlets in a common vacuum chamber, with 32 circular dispenser cathodes operated in space charge limited regime, where the initial circular beam is transformed into an elliptical beam before being collected at the anode. The electron beam optics designed and validated here are at the heart of the first Inverse Geometry CT system, with potential benefits in terms of improved image quality and dramatic X-ray dose reduction for the patient.

  16. /II sifu reflection electron energy loss spectroscopy measurements of low temperature surface cleaning for Si molecular beam epitaxy

    E-Print Network [OSTI]

    Atwater, Harry

    /II sifu reflection electron energy loss spectroscopy measurements of low temperature surface cleaning for Si molecular beam epitaxy Shouleh Nikzad, Selmer S. Wong, Channing C. Ahn, Aimee L. Smith molecular beam epitaxy system, using reflection electron energy loss spectroscopy, in conjunction

  17. Low energy Beam Tracking Under Scattering for a Cold Electron Source in Manchester

    E-Print Network [OSTI]

    Appleby, R; Harvey, M; Jones, M; Kyle, B; Mete, O; Murray, A; Xia, G

    2015-01-01T23:59:59.000Z

    High quality electron beams, with high spatial and tempo- ral resolution, have an important use in electron diffraction experiments to probe and study the constituents of matter. A cold electron source is being developed based on elec- tron ionisation from an atom cloud trapped by using AC magneto-optical methods in the University of Manchester. The technique will produce bunches of electrons well suited for high precision and single shot electron diffraction. In this paper issues of modelling at low energies for this state of art electron source with very low energy spread are presented, with a focus on newly developed tools to model the scat- tering in the meshes used to support the extraction electric fields. The dependence on emittance growth on mesh wire thickness is studied.

  18. Prediction of Material Thermal Properties and Beam-Particle Interaction at

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible forPortsmouth/Paducah ProjectPRE-AWARD ACCOUNTING SYSTEMMeso-Scale during Electron Beam

  19. PLASMA WAKE EXCITATION BY LASERS OR PARTICLE BEAMS C. B. Schroeder, E. Esarey, C. Benedetti, Cs. Toth, C. G. R. Geddes, W. P. Leemans

    E-Print Network [OSTI]

    Geddes, Cameron Guy Robinson

    recent experimental success using lasers and particle beam drivers for plasma acceler- ationPLASMA WAKE EXCITATION BY LASERS OR PARTICLE BEAMS C. B. Schroeder, E. Esarey, C. Benedetti, Cs. T be driven by the ponderomo- tive force of an intense laser or the space-charge force of a charged particle

  20. Electrostatic solitary structures in presence of non-thermal electrons and a warm electron beam on the auroral field lines

    SciTech Connect (OSTI)

    Singh, S. V. [Indian Institute of Geomagnetism, Navi Mumbai (India); School of Physics, University of Kwazulu-Natal, Durban (South Africa); Lakhina, G. S. [Indian Institute of Geomagnetism, Navi Mumbai (India); Bharuthram, R. [University of the Western Cape, Bellville (South Africa); Pillay, S. R. [School of Physics, University of Kwazulu-Natal, Durban (South Africa)

    2011-12-15T23:59:59.000Z

    Electrostatic solitary waves (ESWs) have been observed by satellites in the auroral region of the Earth's magnetosphere. These ESWs are found to be having both positive and negative electrostatic potentials. Using the Sagdeeev psuedo-potential technique, arbitrary amplitude electron-acoustic solitary waves/double layers are studied in an unmagnetized plasma consisting of non-thermally distributed hot electrons, fluid cold electrons, a warm electron beam, and ions. The inertia of the warm electrons, and not the beam speed, is essential for the existence of positive potential solitary structures. Existence domains for positive as well as negative potential electrostatic solitons/double layers are obtained. For the typical auroral region parameters, the electric field amplitude of the negative potential solitons is found to be in the range {approx}(3-30) mV/m and {approx}(5-80) mV/m for the positive potential solitons. For the negative potential solitons/double layers, the amplitudes are higher when their widths are smaller. On the other hand, the amplitude of the positive potential structures increase with their widths.

  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. Description of the Nonlinear and Collective Behavior of Charged-Particle Beams by means of a Nonlinear Schroedinger Equation

    SciTech Connect (OSTI)

    Fedele, Renato [Dipartimento di Scienze Fisiche, Universita Federico II, Napoli Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Naples (Italy); INFN, Napoli Complesso Universitario di M.S. Angelo, via Cintia, I-80126 Naples (Italy); Jovanovic, Dusan [Institute of Physics, P.O. Box 57, Yu-11001 Belgrade (Serbia and Montenegro)

    2004-12-01T23:59:59.000Z

    Charged-particle beams are employed for a number of scientific and technological applications. The conventional description of their collective behavior is usually given in terms of the Vlasov equation. In the last 15 years some alternative descriptions have been developed in terms of a nonlinear Schroedinger equation governing the collective dynamics of the beam while interacting with the surrounding medium. This approach gives new insights, providing an alternative 'key of reading' of the charged-particle beam dynamics, and have been applied to a number of physical problems concerning conventional particle accelerating machines as well as plasma-based accelerator schemes. Remarkably, it is based on a mathematical formalism fully similar to those used for the propagation of e.m. radiation beams in nonlinear media a well as the nonlinear dynamics of the Bose-Einsten condensates.In this paper, a presentation of some significant nonlinear collective effects of a charged-particle beam in particle accelerators, that have been recently investigated in the framework of the above Schroedinger-like descriptions, is given.

  3. Surface Science Analysis of GaAs Photocathodes Following Sustained Electron Beam Delivery

    SciTech Connect (OSTI)

    Shutthanandan, V.; Zhu, Zihua; Stutzman, Marcy L.; Hannon, Fay; Hernandez-Garcia, Carlos; Nandasiri, Manjula I.; Kuchibhatla, Satyanarayana V N T; Thevuthasan, Suntharampillai; Hess, Wayne P.

    2012-06-12T23:59:59.000Z

    Degradation of the photocathode materials employed in photoinjectors represents a challenge for sustained operation of nuclear physics accelerators and high power Free Electron Lasers (FEL). Several photocathode degradation processes are suspected, including defect formation by ion back bombardment, photochemistry of surface adsorbed species and irradiation-induced surface defect formation. To better understand the mechanisms of photocathode degradation, we have conducted surface and bulk analysis studies of two GaAs photocathodes removed from the FEL photoinjector after delivering electron beam for a few years. The analysis techniques include Helium Ion Microscopy (HIM), Rutherford Backscattering Spectrometry (RBS), Atomic Force Microscopy (AFM) and Secondary Ion Mass Spectrometry (SIMS). In addition, strained super-lattice GaAs photocathode samples, removed from the CEBAF photoinjector were analyzed using Transmission Electron Microscopy (TEM) and SIMS. This analysis of photocathode degradation during nominal photoinjector operating conditions represents first steps towards developing robust new photocathode designs necessary for generating sub-micron emittance electron beams required for both fourth generation light sources and intense polarized CW electron beams for nuclear and high energy physics facilities.

  4. Flexible cadmium telluride thin films grown on electron-beam-irradiated graphene/thin glass substrates

    SciTech Connect (OSTI)

    Seo, Won-Oh; Kim, Jihyun, E-mail: hyunhyun7@korea.ac.kr [Department of Chemical and Biological Engineering, Korea University, Anam-dong, Sungbuk-gu, Seoul 136-713 (Korea, Republic of); Koo, Yong Hwan; Kim, Byungnam; Lee, Byung Cheol [Radiation Integrated System Research Division, Korea Atomic Energy Research Institute (KAERI), Daejeon 305-353 (Korea, Republic of); Kim, Donghwan [Department of Materials Science and Engineering, Korea University, Seoul 136-701 (Korea, Republic of)

    2014-08-25T23:59:59.000Z

    We demonstrate the close-spaced sublimation growth of polycrystalline cadmium telluride (CdTe) thin films on a flexible graphene electrode/thin glass substrate structure. Prior to the growth of CdTe films, chemical-vapor-deposited graphene was transferred onto a flexible glass substrate and subjected to electron-beam irradiation at an energy of 0.2?MeV in order to intentionally introduce the defects into it in a controlled manner. Micro-Raman spectroscopy and sheet resistance measurements were employed to monitor the damage and disorder in the electron-beam irradiated graphene layers. The morphology and optical properties of the CdTe thin films deposited on a graphene/flexible glass substrate were systematically characterized. The integration of the defective graphene layers with a flexible glass substrate can be a useful platform to grow various thin-film structures for flexible electronic and optoelectronic devices.

  5. Electron Beam Energy Chirp Control with a Rectangular Corrugated Structure at the Linac Coherent Light Source

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

    Zhang, Zhen; Bane, Karl; Ding, Yantao; Huang, Zhirong; Iverson, Richard; Maxwell, Timothy; Stupakov, Gennady; Wang, Lanfa

    2015-01-30T23:59:59.000Z

    Electron beam energy chirp is an important parameter that affects the bandwidth and performance of a linac-based, free-electron laser. In this paper we study the wakefields generated by a beam passing between at metallic plates with small corrugations, and then apply such a device as a passive dechirper for the Linac Coherent Light Source (LCLS) energy chirp control with a multi-GeV and femtosecond electron beam. Similar devices have been tested in several places at relatively low energies (#24;100 MeV) and with relatively long bunches (> 1ps). In the parameter regime of the LCLS dechirper, with the corrugation size similar to the gap between the plates, the analytical solutions of the wakefields are no longer applicable, and we resort to a #12;field matching program to obtain the wakes. Based on the numerical calculations, we #12;fit the short-range, longitudinal wakes to simple formulas, valid over a large, useful parameter range. Finally, since the transverse wakefields - both dipole and quadrupole-are strong, we compute and include them in beam dynamics simulations to investigate the error tolerances when this device is introduced in the LCLS.

  6. Electron Beam Energy Chirp Control with a Rectangular Corrugated Structure at the Linac Coherent Light Source

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

    Zhang, Zhen; Bane, Karl; Ding, Yantao; Huang, Zhirong; Iverson, Richard; Maxwell, Timothy; Stupakov, Gennady; Wang, Lanfa

    2015-01-30T23:59:59.000Z

    Electron beam energy chirp is an important parameter that affects the bandwidth and performance of a linac-based, free-electron laser. In this paper we study the wakefields generated by a beam passing between at metallic plates with small corrugations, and then apply such a device as a passive dechirper for the Linac Coherent Light Source (LCLS) energy chirp control with a multi-GeV and femtosecond electron beam. Similar devices have been tested in several places at relatively low energies (#24;100 MeV) and with relatively long bunches (> 1ps). In the parameter regime of the LCLS dechirper, with the corrugation size similar tomore »the gap between the plates, the analytical solutions of the wakefields are no longer applicable, and we resort to a #12;field matching program to obtain the wakes. Based on the numerical calculations, we #12;fit the short-range, longitudinal wakes to simple formulas, valid over a large, useful parameter range. Finally, since the transverse wakefields - both dipole and quadrupole-are strong, we compute and include them in beam dynamics simulations to investigate the error tolerances when this device is introduced in the LCLS.« less

  7. 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.

  8. Observation of a single-beam gradient force acoustical trap for elastic particles: acoustical tweezers

    E-Print Network [OSTI]

    Diego Baresch; Jean-Louis Thomas; Régis Marchiano

    2014-11-07T23:59:59.000Z

    The ability to manipulate matter precisely is critical for the study and development of a large variety of systems. Optical tweezers are excellent tools to handle particles ranging in size from a few micrometers to hundreds of nanometers but become inefficient and damaging on larger objects. We demonstrate for the first reported time the trapping of elastic particles by the large gradient force of a single acoustical beam in three dimensions. We show that at equal power, acoustical forces overtake by 8 orders of magnitude that of optical ones on macroscopic objects. Acoustical tweezers can push, pull and accurately control both the position of the particle and the forces exerted under damage-free conditions. The large spectrum of frequencies covered by coherent ultrasonic sources will provide a wide variety of manipulation possibilities from macro- to microscopic length scales. We believe our observations improve the prospects for wider use of non-contact manipulation in biology, biophysics, microfluidics and robotics and bridge the gap that had remained to the macroscopic scale.

  9. Silicon-on-insulator structures formed by a line-source electron beam: Experiment and theory

    SciTech Connect (OSTI)

    Knapp, J.A.

    1985-10-01T23:59:59.000Z

    A line-source electron beam has been used to melt and recrystallize isolated Si layers to form Si-on-insulator structures. Heat flow calculations for these layered structures have been developed which correctly predict the observed recrystallization. Using sample sweep speeds of 100--600 cm/s and peak power densities up to 75 kW/cm/sup 2/ in the 1 x 20-mm beam, we have obtained single-crystal areas as large as 50 x 350 ..mu..m. Seed openings to the substrate are used to control the orientation of the regrowth and the heat flow in the recrystallization film.

  10. Site control technique for quantum dots using electron beam induced deposition

    SciTech Connect (OSTI)

    Iizuka, Kanji; Jung, JaeHun; Yokota, Hiroshi [Nippon Institute of Technology, 4-1 Gakuendai, Miyashiro, Minami-saitama, Saitama 3458501 (Japan)

    2014-05-15T23:59:59.000Z

    To develop simple and high throughput sit definition technique for quantum dots (QDs), the electron beam induced deposition (EBID) method was used as desorption guide of phosphorus atoms form InP substrate. As the results one or a few indium (In) droplets (DLs) were created in the carbon grid pattern by thermal annealing at a temperature of 450°C for 10 min in the ultra high vacuum condition. The size of In DLs was larger than QDs, but arsenide DLs by molecular beam in growth chamber emitted wavelength of 1.028?m at 50K by photoluminescence measurement.

  11. On the fully nonlinear acoustic waves in a plasma with positrons beam impact and superthermal electrons

    SciTech Connect (OSTI)

    Ali Shan, S. [Theoretical Plasma Physics Division, PINSTECH, Nilore, 44000 Islamabad (Pakistan) [Theoretical Plasma Physics Division, PINSTECH, Nilore, 44000 Islamabad (Pakistan); National Centre For Physics (NCP), Shahdra Valley Road, 44000 Islamabad (Pakistan); Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad (Pakistan); El-Tantawy, S. A.; Moslem, W. M. [Department of Physics, Faculty of Science, Port Said University, Port Said 42521 (Egypt)] [Department of Physics, Faculty of Science, Port Said University, Port Said 42521 (Egypt)

    2013-08-15T23:59:59.000Z

    Arbitrary amplitude ion-acoustic waves in an unmagnetized plasma consisting of cold positive ions, superthermal electrons, and positrons beam are reported. The basic set of fluid equations is reduced to an energy-balance like equation. The latter is numerically analyzed to examine the existence regions for solitary and shock waves. It is found that only solitary waves can propagate, however, the model cannot support shocks. The effects of superthermality and beam parameters (via, positrons concentration and streaming velocity) on the existence region, as well as solitary wave profile have been discussed.

  12. Compact disposal of high-energy electron beams using passive or laser-driven plasma decelerating stage

    SciTech Connect (OSTI)

    Bonatto, A.; Schroeder, C.B.; Vay, J.-L.; Geddes, C.R.; Benedetti, C.; Esarey and, E.; Leemans, W.P.

    2014-07-13T23:59:59.000Z

    A plasma decelerating stage is investigated as a compact alternative for the disposal of high-energy beams (beam dumps). This could benefit the design of laser-driven plasma accelerator (LPA) applications that require transportability and or high-repetition-rate operation regimes. Passive and laser-driven (active) plasma-based beam dumps are studied analytically and with particle-in-cell (PIC) simulations in a 1D geometry. Analytical estimates for the beam energy loss are compared to and extended by the PIC simulations, showing that with the proposed schemes a beam can be efficiently decelerated in a centimeter-scale distance.

  13. Monte Carlo calculations of electron beam quality conversion factors for several ion chamber types

    SciTech Connect (OSTI)

    Muir, B. R., E-mail: Bryan.Muir@nrc-cnrc.gc.ca [Measurement Science and Standards, National Research Council Canada, 1200 Montreal Road, Ottawa, Ontario K1A 0R6 (Canada); Rogers, D. W. O., E-mail: drogers@physics.carleton.ca [Carleton Laboratory for Radiotherapy Physics, Physics Department, Carleton University, 1125 ColonelBy Drive, Ottawa, Ontario K1S 5B6 (Canada)

    2014-11-01T23:59:59.000Z

    Purpose: To provide a comprehensive investigation of electron beam reference dosimetry using Monte Carlo simulations of the response of 10 plane-parallel and 18 cylindrical ion chamber types. Specific emphasis is placed on the determination of the optimal shift of the chambers’ effective point of measurement (EPOM) and beam quality conversion factors. Methods: The EGSnrc system is used for calculations of the absorbed dose to gas in ion chamber models and the absorbed dose to water as a function of depth in a water phantom on which cobalt-60 and several electron beam source models are incident. The optimal EPOM shifts of the ion chambers are determined by comparing calculations of R{sub 50} converted from I{sub 50} (calculated using ion chamber simulations in phantom) to R{sub 50} calculated using simulations of the absorbed dose to water vs depth in water. Beam quality conversion factors are determined as the calculated ratio of the absorbed dose to water to the absorbed dose to air in the ion chamber at the reference depth in a cobalt-60 beam to that in electron beams. Results: For most plane-parallel chambers, the optimal EPOM shift is inside of the active cavity but different from the shift determined with water-equivalent scaling of the front window of the chamber. These optimal shifts for plane-parallel chambers also reduce the scatter of beam quality conversion factors, k{sub Q}, as a function of R{sub 50}. The optimal shift of cylindrical chambers is found to be less than the 0.5 r{sub cav} recommended by current dosimetry protocols. In most cases, the values of the optimal shift are close to 0.3 r{sub cav}. Values of k{sub ecal} are calculated and compared to those from the TG-51 protocol and differences are explained using accurate individual correction factors for a subset of ion chambers investigated. High-precision fits to beam quality conversion factors normalized to unity in a beam with R{sub 50} = 7.5 cm (k{sub Q}{sup ?}) are provided. These factors avoid the use of gradient correction factors as used in the TG-51 protocol although a chamber dependent optimal shift in the EPOM is required when using plane-parallel chambers while no shift is needed with cylindrical chambers. The sensitivity of these results to parameters used to model the ion chambers is discussed and the uncertainty related to the practical use of these results is evaluated. Conclusions: These results will prove useful as electron beam reference dosimetry protocols are being updated. The analysis of this work indicates that cylindrical ion chambers may be appropriate for use in low-energy electron beams but measurements are required to characterize their use in these beams.

  14. D-T Mixture Control with Neutral Beam Fuelling and Importance of Particle Recycling and Isotope Exchange in the JET ELM-free H-mode

    E-Print Network [OSTI]

    D-T Mixture Control with Neutral Beam Fuelling and Importance of Particle Recycling and Isotope Exchange in the JET ELM-free H-mode

  15. Joining Uranium to Aluminum using Electron Beam Welding and an Explosively Clad Niobium Interlayer

    SciTech Connect (OSTI)

    Elmer, J W; Terrill, P; Brasher, D; Butler, D

    2001-06-12T23:59:59.000Z

    A uranium alloy was joined to a high strength aluminum alloy using a commercially pure niobium interlayer. Joining of the Nb interlayer to the aluminum alloy was performed using an explosive welding process, while joining the Nb interlayer to the uranium alloy was performed using an electron beam welding process. Explosive welding was selected to bond the Nb to the aluminum alloy in order to minimize the formation of brittle intermetallic phases. Electron beam welding was selected to join the Nb to the uranium alloy in order to precisely control melting so as to minimize mixing of the two metals. A Modified Faraday Cup (MFC) technique using computer-assisted tomography was employed to determine the power distribution of the electron beam so that the welding parameters could be directly transferred to other welding machines. Optical microscopy, scanning electron microscopy, microhardness, and tensile testing of the welds were used to characterize the resulting joints. This paper presents the welding techniques and processing parameters that were developed to produce high integrity ductile joints between these materials.

  16. Laser or charged-particle-beam fusion reactor with direct electric generation by magnetic flux compression

    DOE Patents [OSTI]

    Lasche, G.P.

    1983-09-29T23:59:59.000Z

    The invention is a laser or particle-beam-driven fusion reactor system which takes maximum advantage of both the very short pulsed nature of the energy release of inertial confinement fusion (ICF) and the very small volumes within which the thermonuclear burn takes place. The pulsed nature of ICF permits dynamic direct energy conversion schemes such as magnetohydrodynamic (MHD) generation and magnetic flux compression; the small volumes permit very compact blanket geometries. By fully exploiting these characteristics of ICF, it is possible to design a fusion reactor with exceptionally high power density, high net electric efficiency, and low neutron-induced radioactivity. The invention includes a compact blanket design and method and apparatus for obtaining energy utilizing the compact blanket.

  17. Micro-cone targets for producing high energy and low divergence particle beams

    DOE Patents [OSTI]

    Le Galloudec, Nathalie

    2013-09-10T23:59:59.000Z

    The present invention relates to micro-cone targets for producing high energy and low divergence particle beams. In one embodiment, the micro-cone target includes a substantially cone-shaped body including an outer surface, an inner surface, a generally flat and round, open-ended base, and a tip defining an apex. The cone-shaped body tapers along its length from the generally flat and round, open-ended base to the tip defining the apex. In addition, the outer surface and the inner surface connect the base to the tip, and the tip curves inwardly to define an outer surface that is concave, which is bounded by a rim formed at a juncture where the outer surface meets the tip.

  18. Cloud a particle beam facility to investigate the influence of cosmic rays on clouds

    E-Print Network [OSTI]

    Kirkby, Jasper

    2001-01-01T23:59:59.000Z

    Palaeoclimatic data provide extensive evidence for solar forcing of the climate during the Holocene and the last ice age, but the underlying mechanism remains a mystery. However recent observations suggest that cosmic rays may play a key role. Satellite data have revealed a surprising correlation between cosmic ray intensity and the fraction of the Earth covered by low clouds \\cite{svensmark97,marsh}. Since the cosmic ray intensity is modulated by the solar wind, this may be an important clue to the long-sought mechanism for solar-climate variability. In order to test whether cosmic rays and clouds are causally linked and, if so, to understand the microphysical mechanisms, a novel experiment known as CLOUD\\footnotemark\\ has been proposed \\cite{cloud_proposal}--\\cite{cloud_addendum_2}. CLOUD proposes to investigate ion-aerosol-cloud microphysics under controlled laboratory conditions using a beam from a particle accelerator, which provides a precisely adjustable and measurable artificial source of cosmic rays....

  19. Linear theory of large-orbit gyrotron traveling wave amplifiers with misaligned electron beam

    SciTech Connect (OSTI)

    Jiao Chongqing [Beijing Key Laboratory of High Voltage and EMC, North China Electric Power University, Beijing 102206 (China); Luo Jirun [Institute of Electronics, Chinese Academy of Sciences, Beijing 100080 (China)

    2010-11-15T23:59:59.000Z

    A linear theory of large-orbit gyrotron traveling wave amplifiers (gyro-TWAs), which can be applied to analyze the effect of electron beam misalignment, is developed by specializing the corresponding theory of small-orbit gyro-TWAs. The linear theory is validated by comparing with a nonlinear theory. Numerical results show that beam misalignment can reduce linear gain and amplification bandwidth of large-orbit gyro-TWAs and increase the starting length of large-orbit gyro-BWOs for modes in accordance with the mode-selective condition. In addition, beam misalignment can also break the limitation of mode-selective condition and make the instability problem more complex.

  20. Monte Carlo calculations for reference dosimetry of electron beams with the PTW Roos and NE2571 ion chambers

    SciTech Connect (OSTI)

    Muir, B. R., E-mail: bmuir@physics.carleton.ca; Rogers, D. W. O., E-mail: drogers@physics.carleton.ca [Physics Department, Carleton Laboratory for Radiotherapy Physics, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6 (Canada)] [Physics Department, Carleton Laboratory for Radiotherapy Physics, Carleton University, 1125 Colonel By Drive, Ottawa, Ontario K1S 5B6 (Canada)

    2013-12-15T23:59:59.000Z

    Purpose: To investigate recommendations for reference dosimetry of electron beams and gradient effects for the NE2571 chamber and to provide beam quality conversion factors using Monte Carlo simulations of the PTW Roos and NE2571 ion chambers. Methods: The EGSnrc code system is used to calculate the absorbed dose-to-water and the dose to the gas in fully modeled ion chambers as a function of depth in water. Electron beams are modeled using realistic accelerator simulations as well as beams modeled as collimated point sources from realistic electron beam spectra or monoenergetic electrons. Beam quality conversion factors are calculated with ratios of the doses to water and to the air in the ion chamber in electron beams and a cobalt-60 reference field. The overall ion chamber correction factor is studied using calculations of water-to-air stopping power ratios. Results: The use of an effective point of measurement shift of 1.55 mm from the front face of the PTW Roos chamber, which places the point of measurement inside the chamber cavity, minimizes the difference betweenR{sub 50}, the beam quality specifier, calculated from chamber simulations compared to that obtained using depth-dose calculations in water. A similar shift minimizes the variation of the overall ion chamber correction factor with depth to the practical range and reduces the root-mean-square deviation of a fit to calculated beam quality conversion factors at the reference depth as a function of R{sub 50}. Similarly, an upstream shift of 0.34 r{sub cav} allows a more accurate determination of R{sub 50} from NE2571 chamber calculations and reduces the variation of the overall ion chamber correction factor with depth. The determination of the gradient correction using a shift of 0.22 r{sub cav} optimizes the root-mean-square deviation of a fit to calculated beam quality conversion factors if all beams investigated are considered. However, if only clinical beams are considered, a good fit to results for beam quality conversion factors is obtained without explicitly correcting for gradient effects. The inadequacy of R{sub 50} to uniquely specify beam quality for the accurate selection of k{sub Q} factors is discussed. Systematic uncertainties in beam quality conversion factors are analyzed for the NE2571 chamber and amount to between 0.4% and 1.2% depending on assumptions used. Conclusions: The calculated beam quality conversion factors for the PTW Roos chamber obtained here are in good agreement with literature data. These results characterize the use of an NE2571 ion chamber for reference dosimetry of electron beams even in low-energy beams.

  1. A 2D simulation study of Langmuir, whistler, and cyclotron maser instabilities induced by an electron ring-beam distribution

    SciTech Connect (OSTI)

    Lee, K. H.; Lee, L. C. [Institute of Space Science, National Central University, Taoyuan, Taiwan (China); Omura, Y. [Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Kyoto (Japan)

    2011-09-15T23:59:59.000Z

    We carried out a series of 2D simulations to study the beam instability and cyclotron maser instability (CMI) with the initial condition that a population of tenuous energetic electrons with a ring-beam distribution is present in a magnetized background plasma. In this paper, weakly relativistic cases are discussed with the ring-beam kinetic energy ranging from 25 to 100 keV. The beam component leads to the two-stream or beam instability at an earlier stage, and the beam mode is coupled with Langmuir or whistler mode, leading to excitation of beam-Langmuir or beam-whistler waves. When the beam velocity is large with a strong beam instability, the initial ring-beam distribution is diffused in the parallel direction rapidly. The diffused distribution may still support CMI to amplify the X1 mode (the fundamental X mode). On the contrary, when the beam velocity is small and the beam instability is weak, CMI can amplify the Z1 (the fundamental Z mode) effectively while the O1 (the fundamental O mode) and X2 (the second harmonic X mode) modes are very weak and the X1 mode is not excited. In this report, different cases with various parameters are presented and discussed for a comprehensive understanding of ring-beam instabilities.

  2. Current-driven ion-acoustic and potential-relaxation instabilities excited in plasma plume during electron beam welding

    SciTech Connect (OSTI)

    Trushnikov, D. N., E-mail: trdimitr@yandex.ru [The department for Applied Physics, Perm National Research Polytechnic University, Perm, 614990 (Russian Federation); Mladenov, G. M., E-mail: gmmladenov@abv.bg; Koleva, E. G., E-mail: eligeorg@abv.bg [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko Shose, 1784, Sofia (Bulgaria); Technology Centre of Electron Beam and Plasma Technologies and Techniques, 68-70 Vrania, ap.10, Banishora,1309, Sofia (Bulgaria); Belenkiy, V. Ya., E-mail: mtf@pstu.ru; Varushkin, S. V., E-mail: stepan.varushkin@mail.ru [The department for Welding Production and Technology of Constructional Materials, Perm National Research Polytechnic University, Perm, 614990 (Russian Federation)

    2014-04-15T23:59:59.000Z

    Many papers have sought correlations between the parameters of secondary particles generated above the beam/work piece interaction zone, dynamics of processes in the keyhole, and technological processes. Low- and high-frequency oscillations of the current, collected by plasma have been observed above the welding zone during electron beam welding. Low-frequency oscillations of secondary signals are related to capillary instabilities of the keyhole, however; the physical mechanisms responsible for the high-frequency oscillations (>10 kHz) of the collected current are not fully understood. This paper shows that peak frequencies in the spectra of the collected high-frequency signal are dependent on the reciprocal distance between the welding zone and collector electrode. From the relationship between current harmonics frequency and distance of the collector/welding zone, it can be estimated that the draft velocity of electrons or phase velocity of excited waves is about 1600 m/s. The dispersion relation with the properties of ion-acoustic waves is related to electron temperature 10 000 K, ion temperature 2 400 K and plasma density 10{sup 16} m{sup ?3}, which is analogues to the parameters of potential-relaxation instabilities, observed in similar conditions. The estimated critical density of the transported current for creating the anomalous resistance state of plasma is of the order of 3 A·m{sup ?2}, i.e. 8 mA for a 3–10 cm{sup 2} collector electrode. Thus, it is assumed that the observed high-frequency oscillations of the current collected by the positive collector electrode are caused by relaxation processes in the plasma plume above the welding zone, and not a direct demonstration of oscillations in the keyhole.

  3. 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.

  4. Design of CCD camera system for use inside electron beam furnace

    SciTech Connect (OSTI)

    Sze, J.S.

    1992-10-01T23:59:59.000Z

    The design of a wide dynamic range camera system for use inside Electron Beam furnaces is presented. The camera system is designed for used in high vacuum and in a high radiant heat flux environment looking directly into a high metallic vapor flux. In addition, the camera is designed to have a dynamic range that can provide a good image in both low light level conditions as well as in high brightness situations as when the electron beam impinging on the melt surface. An analysis is given for estimating the dynamic range of the camera imaging system and the camera cooling requirements. Techniques for capturing and recording video images are also presented. The application of various optical filters and liquid crystal variable attenuators for the camera imaging system is discussed.

  5. Electron-beam scull melting with electromagnetic stirring of melt in crucible

    SciTech Connect (OSTI)

    Ladokhin, S.V. [Institute for Casting Problems, Kiev (Ukraine)

    1994-12-31T23:59:59.000Z

    The technologies and equipment have been developed for electron-beam scull melting with electromagnetic stirring of melt for some Ni-based superalloys as well as for multi-component Ti-, Zr-, Nb-, and Mo-based alloys. Two types of scull crucible sets with electromagnetic stirring systems have been constructed, with the metal pouring by the crucible tilting or through the hole in the crucible bottom. In the second case slag does not fall into a mold, and the electron beam may be used for metal heating in the costing head, thus improving the quality of castings. The technologies developed allow to utilize scrap, cost part reverts, chips etc. thus saving virgin alloys. The electromagnetic stirring application permits to product multi-component alloys, to increase the mass of the metal poured, and to reduce the specific energy expenditure and metal loss through evaporation.

  6. Efficient method of gas laser pumping by an electron beam in the SIGE-1 experimental setup

    SciTech Connect (OSTI)

    Arlantsev, S. V., E-mail: arlantsev@mail.ru [Orlov Special Design Engineering Bureau of High-Energy Lasers 'Granat,' (Russian Federation); Kuz'min, G. P.; Minaev, I. M.; Mkheidze, G. P.; Tikhonevich, O. V.; Ul'yanov, D. K. [Russian Academy of Sciences, Prokhorov Institute of General Physics (Russian Federation)

    2011-12-15T23:59:59.000Z

    Lasers, sources of coherent UV and vacuum UV radiation, plasmachemical reactors, reactors for cleaning fouled gases, etc., can be classified as devices the working medium of which is plasma formed as a result of the interaction of a high-current relativistic electronic beam with gas. Efficiency of such devices which are united under the common name 'systems of injection gas electronics' (SIGE) depends mainly on the efficiency of energy transfer from a beam to gas ({eta}g = W{sub g}/W{sub b}) and that of the transform of the energy transferred to gas into the energy of the ultimate product W{sub in} ({eta}{sub in} = W{sub in}/W{sub g}). As a special case of SIGE, an experimental bench laser is considered. The new efficient method of pumping is supposed to be implemented on this laser to optimize the energy contribution {eta}{sub g} and useful output {eta}{sub in}.

  7. Simulation of multicomponent losses in electron beam melting and refining at varying scan frequencies

    SciTech Connect (OSTI)

    Powell, A.; Szekely, J. [Massachusetts Institute of Technology, Cambridge, MA (United States); Avyle, J.V.D.; Damkroger, B. [Sandia National Laboratories, Albuquerque, NM (United States)

    1995-12-31T23:59:59.000Z

    A two-stage model is presented to describe alloy element evaporation rates from molten metal due to transient local heating by an electron beam. The first stage is a simulation of transient phenomena near the melt surface due to periodic heating by a scanning beam, the output of which is the relationship between operating parameters, surface temperature, and evaporation rate. At high scan rates, this can be done using a simple one-dimensional heat transfer model of the surface layer; at lower scan rates, a more complex three-dimensional model with fluid flow and periodic boundary conditions is necessary. The second stage couples this evaporation-surface temperature relationship with a larger steady state heat transfer and fluid flow model of an entire melting hearth or mold, in order to calculate local and total evaporation rates. Predictions are compared with experimental results from Sandia`s 310-kW electron beam melting furnace, in which evaporation rates and vapor compositions were studied in pure titanium and Ti-6%Al-4%V alloy. Evaporation rates were estimated from rate of condensation on a substrate held over the hearth, and were characterized as a function of beam power (10{sup {minus}3}, 10{sup {minus}4} and 10{sup {minus}5} torr).

  8. Simulation of multicomponent losses in electron beam melting and refining at varying scan frequencies

    SciTech Connect (OSTI)

    Powell, A.; Szekely, J. [Massachusetts Inst. of Tech., Cambridge, MA (United States); Van Den Avyle, J.; Damkroger, B. [Sandia National Labs., Albuquerque, NM (United States)

    1995-10-12T23:59:59.000Z

    A two-stage model is presented to describe alloy element evaporation rates from molten metal due to transient local heating by an electron beam. The first stage is a simulation of transient phenomena near the melt surface due to periodic heating by a scanning beam, the output of which is the relationship between operating parameters, surface temperature, and evaporation rate. At high scan rates, this can be done using a simple one-dimensional heat transfer model of the surface layer; at lower scan rates, a more complex three-dimensional model with fluid flow and periodic boundary conditions is necessary. The second stage couples this evaporation-surface temperature relationship with a larger steady state heat transfer and fluid flow model of an entire melting hearth or mold, in order to calculate local and total evaporation rates. Predictions are compared with experimental results from Sandia`s 310-kW electron beam melting furnace, in which evaporation rates and vapor compositions were studied in pure titanium and Ti-6%Al-4%V alloy. Evaporation rates were estimated from rate of condensation on a substrate held over the hearth, and were characterized as a function of beam power (150 and 225 kW), scan frequency (30, 115 and 450 Hz) and background pressure (10{sup {minus}3}, 10{sup {minus}4} and 10{sup {minus}5} torr).

  9. Wavelet Bicoherence Analysis as a Method for Investigating Coherent Structures in an Electron Beam with an Overcritical Current

    E-Print Network [OSTI]

    A. A. Koronovskii; A. E. Hramov

    2006-01-31T23:59:59.000Z

    Results are presented from numerical modeling of the effect of the inhomogeneity of the ion background on the complicated spatiotemporal dynamics of an electron beam with a virtual cathode in plane geometry. The possibility is demonstrated of increasing the generation frequency without changing the beam current. The spatiotemporal structures that form in the beam and govern the complicated stochastic dynamics of the nonuniform electron-plasma system under consideration are investigated by the methods of wavelet bicoherence and by analyzing the calculated electron trajectories on the space-time diagrams

  10. A Spin-Light Polarimeter for Multi-GeV Longitudinally Polarized Electron Beams

    SciTech Connect (OSTI)

    Mohanmurthy, Prajwal [Mississippi State University, Starkville, MS (United States); Dutta, Dipangkar [Mississippi State University, Starkville, MS (United States) and Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2014-02-01T23:59:59.000Z

    The physics program at the upgraded Jefferson Lab (JLab) and the physics program envisioned for the proposed electron-ion collider (EIC) include large efforts to search for interactions beyond the Standard Model (SM) using parity violation in electroweak interactions. These experiments require precision electron polarimetry with an uncertainty of < 0.5 %. The spin dependent Synchrotron radiation, called "spin-light," can be used to monitor the electron beam polarization. In this article we develop a conceptual design for a "spin-light" polarimeter that can be used at a high intensity, multi-GeV electron accelerator. We have also built a Geant4 based simulation for a prototype device and report some of the results from these simulations.

  11. Antimicrobial packaging system for optimization of electron beam irradiation of fresh produce

    E-Print Network [OSTI]

    Han, Jaejoon

    2006-10-30T23:59:59.000Z

    . These films can control microbial contamination by reducing the growth rate and maximum growth population, as well as extending the lag period of the target microorganism, and therefore should help to prolong the product shelf life and maintain its safety... with 4 low-dose electron beam irradiation (1-3 kGy) provides a synergistic preservative effect, and therefore one can ensure the microbial safety of minimally processed leafy vegetables with negligible quality loss. The specific objectives are: 1...

  12. Characterization of U-6Nb ingots produced via the electron beam cold hearth refining process

    SciTech Connect (OSTI)

    McKoon, R.H.

    1997-11-14T23:59:59.000Z

    A study was undertaken at Lawrence Livermore National Laboratory to characterize uranium, 6% niobium ingots produced via electron beam melting, hearth refining and continuous casting and to compare this material with conventional VIM/skull melt/VAR material. Samples of both the ingot and feed material were analyzed for niobium and trace metallic elements, carbon, oxygen and nitrogen. This material was also inspected metallographically and via microprobe analysis.

  13. 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.

  14. Note: Production of a mercury beam with an electron cyclotron resonance ion source

    SciTech Connect (OSTI)

    Vondrasek, R.; Pardo, R.; Scott, R. [Physics Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States)] [Physics Division, Argonne National Laboratory, Lemont, Illinois 60439 (United States)

    2013-11-15T23:59:59.000Z

    An electron cyclotron resonance ion source has been utilized to produce mercury beams with intensities of 4.5 e?A of {sup 202}Hg{sup 29+} and 3.0 e?A of {sup 202}Hg{sup 31+} from natural abundance mercury metal. The production technique relies on the evaporation of liquid mercury into the source plasma vacuum region and utilizes elemental mercury instead of a volatile organic compound as the neutral feed material.

  15. Compton and double Compton scattering processes at colliding electron-photon beams

    E-Print Network [OSTI]

    A. N. Ilyichev; E. A. Kuraev; V. Bytev; Yu. P. Peresun'ko

    2005-01-21T23:59:59.000Z

    Radiative corrections (RC) to the Compton scattering cross section are calculated in the leading and next-to leading logarithmic approximation to the case of colliding high energy photon-electron beams. RC to the double Compton scattering cross section in the same experimental set-up are calculated in the leading logarithmic approximation. We consider the case when no pairs are created in the final state. We show that the differential cross section can be written in the form of the Drell-Yan process cross-section. Numerical values of the $K$-factor and the leading order distribution on the scattered electron energy fraction and scattering angle are presented.

  16. 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.

  17. Coherent Electron Cooling: JLab Effort Helps to Cool Particle...

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

    labmanager.com?articles.viewarticleNo7392titleCoherent-Electron-Cooling--Combining-Methods-to-Cool-Parti... Submitted: Friday, April 13...

  18. Analytic model of bunched beams for harmonic generation in the low-gain free electron laser regime

    E-Print Network [OSTI]

    Wurtele, Jonathan

    Analytic model of bunched beams for harmonic generation in the low-gain free electron laser regime employs free electron lasers (FELs) with two undulators: the first uses a seed laser to modulate Many proposed x-ray free electron lasers (FELs) are designed to produce radiation starting from

  19. Instrumentation and Beam Dynamics Study of Advanced Electron-Photon Facility in Indiana University

    SciTech Connect (OSTI)

    Luo, Tianhuan; /Indiana U.

    2011-08-01T23:59:59.000Z

    The Advanced eLectron-PHoton fAcility (ALPHA) is a compact electron accelerator under construction and being commissioned at the Indiana University Center for Exploration of Energy and Matter (CEEM). In this thesis, we have studied the refurbished Cooler Injector Synchrotron (CIS) RF cavity using both the transmission line model and SUPERFISH simulation. Both low power and high power RF measurements have been carried out to characterize the cavity. Considering the performance limit of ferrite, we have designed a new ferrite loaded, co-axial quarter wave like cavity with similar structure but a more suitable ferrite material. We have also designed a traveling wave stripline kicker for fast extraction by POISSON and Microwave Studio. The strips geometry is trimmed to maximize the uniformity of the kicking field and match the impedance of the power cables. The time response simulation shows the kicker is fast enough for machine operation. The pulsed power supply requirement has also been specified. For the beam diagnosis in the longitudinal direction, we use a wideband Wall Gap Monitor (WGM) served in CIS. With proper shielding and amplification to get good WGM signal, we have characterized the injected and extracted beam signal in single pass commissioning, and also verified the debunching effect of the ALPHA storage ring. A modulation-demodulation signal processing method is developed to measure the current and longitudinal profile of injected beam. By scanning the dipole strength in the injection line, we have reconstructed the tomography of the longitudinal phase space of the LINAC beam. In the accumulation mode, ALPHA will be operated under a low energy and high current condition, where intra beam scattering (IBS) becomes a dominant effect on the beam emittance. A self consistent simulation, including IBS effect, gas scattering and linear coupling, has been carried out to calculate the emittance of the stored beam.

  20. Breaking the Attosecond, Angstrom and TV/M Field Barriers with Ultra-Fast Electron Beams

    SciTech Connect (OSTI)

    Rosenzweig, James; Andonian, Gerard; Fukasawa, Atsushi; Hemsing, Erik; Marcus, Gabriel; Marinelli, Agostino; Musumeci, Pietro; O'Shea, Brendan; O'Shea, Finn; Pellegrini, Claudio; Schiller, David; Travish, Gil; /UCLA; Bucksbaum, Philip; Hogan, Mark; Krejcik, Patrick; /SLAC; Ferrario, Massimo; /INFN, Rome; Full, Steven; /Penn State U.; Muggli, Patric; /Southern California U.

    2012-06-22T23:59:59.000Z

    Recent initiatives at UCLA concerning ultra-short, GeV electron beam generation have been aimed at achieving sub-fs pulses capable of driving X-ray free-electron lasers (FELs) in single-spike mode. This use of very low Q beams may allow existing FEL injectors to produce few-100 attosecond pulses, with very high brightness. Towards this end, recent experiments at the LCLS have produced {approx}2 fs, 20 pC electron pulses. We discuss here extensions of this work, in which we seek to exploit the beam brightness in FELs, in tandem with new developments in cryogenic undulator technology, to create compact accelerator-undulator systems that can lase below 0.15 {angstrom}, or be used to permit 1.5 {angstrom} operation at 4.5 GeV. In addition, we are now developing experiments which use the present LCLS fs pulses to excite plasma wakefields exceeding 1 TV/m, permitting a table-top TeV accelerator for frontier high energy physics applications.

  1. 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.

  2. 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.

  3. Surface science analysis of GaAs photocathodes following sustained electron beam delivery

    SciTech Connect (OSTI)

    Carlos Hernandez-Garcia, Fay Hannon, Marcy Stutzman, V. Shutthanandan, Z. Zhu, M. Nandasri, S. V. Kuchibhatla, S. Thevuthasan, W. P. Hess

    2012-06-01T23:59:59.000Z

    Degradation of the photocathode materials employed in photoinjectors represents a challenge for sustained operation of nuclear physics accelerators and high power Free Electron Lasers (FEL). Photocathode quantum efficiency (QE) degradation is due to residual gasses in the electron source vacuum system being ionized and accelerated back to the photocathode. These investigations are a first attempt to characterize the nature of the photocathode degradation, and employ multiple surface and bulk analysis techniques to investigate damage mechanisms including sputtering of the Cs-oxidant surface monolayer, other surface chemistry effects, and ion implantation. Surface and bulk analysis studies were conducted on two GaAs photocathodes, which were removed from the JLab FEL DC photoemission gun after delivering electron beam, and two control samples. The analysis techniques include Helium Ion Microscopy (HIM), Rutherford Backscattering Spectrometry (RBS), Atomic Force Microscopy (AFM) and Secondary Ion Mass Spectrometry (SIMS). In addition, two high-polarization strained superlattice GaAs photocathode samples, one removed from the Continuous Electron Beam Accelerator Facility (CEBAF) photoinjector and one unused, were also analyzed using Transmission Electron Microscopy (TEM) and SIMS. It was found that heat cleaning the FEL GaAs wafer introduces surface roughness, which seems to be reduced by prolonged use. The bulk GaAs samples retained a fairly well organized crystalline structure after delivering beam but shows evidence of Cs depletion on the surface. Within the precision of the SIMS and RBS measurements the data showed no indication of hydrogen implantation or lattice damage from ion back bombardment in the bulk GaAs wafers. In contrast, SIMS and TEM measurements of the strained superlattice photocathode show clear crystal damage in the wafer from ion back bombardment.

  4. Technical Challenges and Scientific Payoffs of Muon Beam Accelerators for Particle Physics

    E-Print Network [OSTI]

    Zisman, Michael S.

    2008-01-01T23:59:59.000Z

    of 2006 European Particle Accelerator Conf. , Edinburgh,Proc. 1992 European Particle Accelerator Conference, Berlin,in Proc. 2007 Particle Accelerator Conf. , Albuquerque, June

  5. Experimental demonstration of longitudinal beam phase space linearizer in a free-electron laser facility by corrugated structures

    E-Print Network [OSTI]

    Deng, Haixiao; Feng, Chao; Zhang, Tong; Wang, Xingtao; Lan, Taihe; Feng, Lie; Zhang, Wenyan; Liu, Xiaoqing; Yao, Haifeng; Shen, Lei; Li, Bin; Zhang, Junqiang; Li, Xuan; Fang, Wencheng; Wang, Dan; Couprie, Marie-emmanuelle; Lin, Guoqiang; Liu, Bo; Gu, Qiang; Wang, Dong; Zhao, Zhentang

    2014-01-01T23:59:59.000Z

    Removal of residual linear energy chirp and intrinsic nonlinear energy curvature in the relativistic electron beam from radiofrequency linear accelerator is of paramount importance for efficient lasing of a high-gain free-electron laser. Recently, it was theoretically and experimentally demonstrated that the longitudinal wakefield excited by the electrons itself in the corrugated structure allows for precise control of the electron beam phase space. In this Letter, we report the first utilization of a corrugated structure as beam linearizer in the operation of a seeded free-electron laser driven by a 140 MeV linear accelerator, where a gain of ~10,000 over spontaneous emission was achieved at the second harmonic of the 1047 nm seed laser, and a free-electron laser bandwidth narrowing by about 50% was observed, in good agreement with the theoretical expectations.

  6. THE EFFECTS OF ELECTRON BEAM IRRADIATION AND SANITIZERS IN THE REDUCTION OF PATHOGENS AND ATTACHMENT PREVENTION ON SPINACH

    E-Print Network [OSTI]

    Neal, Jack A.

    2010-07-14T23:59:59.000Z

    The effects of electron beam (e-beam) irradiation and sanitizers in the reduction of Escherichia coli O157:H7 and Salmonella counts and attachment prevention on spinach was studied. Survival of these pathogens in spinach was observed at multiple...

  7. 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.

  8. Postplasma particle dynamics in a Gaseous Electronics Conference RF Reference Cell

    SciTech Connect (OSTI)

    Collins, S.M. [Department of Electrical and Computer Engineering, University of Arizona, Tucson, Arizona 85721 (United States)] [Department of Electrical and Computer Engineering, University of Arizona, Tucson, Arizona 85721 (United States); Brown, D.A. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); O`Hanlon, J.F.; Carlile, R.N. [Department of Electrical and Computer Engineering, University of Arizona, Tucson, Arizona 85721 (United States)] [Department of Electrical and Computer Engineering, University of Arizona, Tucson, Arizona 85721 (United States)

    1995-11-01T23:59:59.000Z

    Particle contamination in plasma tools used for the manufacture of very large scale integrated semiconductor devices on silicon wafers is a major cause of yield loss. Understanding the dynamics of particle movement in the postplasma regime is important to explain the process of their transport to the wafer. The movement of particle contamination in a Gaseous Electronics Conference RF Reference Cell in the postplasma regime was investigated using a novel technique. Particle clouds were observed using laser light scattering together with an image intensifier and a monochromator. This technique allowed particle clouds of low density, that could not otherwise be detected, to be seen. Video analysis of the particles showed movement of the cloud front during the first second after the plasma was extinguished. Using the particle terminal velocity to estimate particle size, we estimate diameters of 0.11 {mu}m in argon and 0.05 {mu}m in krypton. The role of the thermophoretic force on particles during the postplasma was shown to be larger than gravitational forces and to dominate particle transport for small particles under the conditions investigated. A temperature gradient of 12 {degree}C/cm was observed to move these particles away from a warm electrode as the plasma was extinguished and the particles were released from the electrostatic confinement forces generated by the plasma. {copyright} {ital 1995} {ital American} {ital Vacuum} {ital Society}

  9. Effect of flux addition on the microstructure and hardness of TiC-reinforced ferrous surface composite layers fabricated by high-energy electron beam irradiation

    SciTech Connect (OSTI)

    Choo, S.H.; Lee, S.; Kwon, S.J.

    1999-12-01T23:59:59.000Z

    Surface composites reinforced with TiC particulates were fabricated by high-energy electron-beam irradiation. In order to investigate the effects of flux addition on the TiC dispersion in surface composite layers, four kinds of powder mixtures were made by mixing TiC with 5, 10, 20, and 40 wt% of the flux components (MgO-CaO). To fabricate TiC-reinforced surface composites, the TiC-flux mixtures were deposited evenly on a plain carbon steel substrate, which was subjected to electron-beam irradiation. Microstructural analysis was conducted using X-ray diffraction and Moessbauer spectroscopy as well as optical and scanning electron microscopy. The microstructure of the surface composites was composed of a melted region, an interfacial region, a coarse-grained heat-affected zone (HAZ), a fine-grained HAZ, and an unaltered original substrate region. TiC agglomerates and residual pores were found in the melted region of materials processed without flux, but the number of agglomerates and pores are significantly decreased in materials processed with a considerable amount of flux. As a result of irradiation, TiC particles were homogeneously distributed throughout the melted region of 2.5 mm in thickness, whose hardness was greatly increased. The optimum flux amount, which resulted in surface composites containing homogeneously dispersed TiC particles, was found to be in the range of 10 to 20% to obtain excellent surface composites.

  10. Ceramic-metallic coatings by electron beam physical vapor deposition (EB-PVD) process

    SciTech Connect (OSTI)

    Wolfe, D.E.; Singh, J. [Pennsylvania State Univ., State College, PA (United States)

    1995-12-31T23:59:59.000Z

    Electron Beam Physical Vapor Deposition (EB-PVD) process is considered to be a technology that has overcome some of the difficulties or problems associated with the chemical vapor deposition (CVD), physical vapor deposition (PVD) and metal spray processes. The EB-PVD process offers many desirable characteristics such as relatively high deposition rates (up to 100-150 {mu}m/minute with an evaporation rate {approx}10-15 Kg/hour,) dense coatings, precise compositional control, columnar and poly-crystalline microstructure, low contamination, and high thermal efficiency. Various metallic and ceramic coatings (oxides, carbides, nitrides) can be deposited at relatively low temperatures. Even elements with low vapor pressure such as molybdenum, tungsten, and carbon are readily evaporated by this process. In addition, EB-PVD is capable of producing multi-layered laminated metallic/ceramic coatings on large components by changing the EB-PVD processing conditions such as ingot composition, part manipulation, and electron beam energy. Attachment of an ion assisted beam source to the EB-PVD offers additional benefits such as dense coatings with improved adhesion. In addition, textured coatings can be obtained that are desirable in many applications such as cutting tools. This laboratory has started a new thrust in the coating area by the EB-PVD process. The microstructure of thermal barrier ceramic coatings (i.e., yttria stabilized zirconia) developed by the EB-PVD process will be presented.

  11. Dosimetric Impact of Surgical Clips in Electron Beam Treatment of Breast Cancer

    SciTech Connect (OSTI)

    Gossman, Michael S. [Tri-State Regional Cancer Center, Ashland, KY (United States)], E-mail: mgossman@tsrcc.com; Zhao Li [Midwest Proton Radiotherapy Institute, Bloomington, IN (United States); Cao Minsong [Indiana University, School of Medicine, Department of Radiation Oncology, Indianapolis, IN (United States); Lopez, Jeffrey P. [Tri-State Regional Cancer Center, Ashland, KY (United States); Das, Indra J. [Midwest Proton Radiotherapy Institute, Bloomington, IN (United States); Indiana University, School of Medicine, Department of Radiation Oncology, Indianapolis, IN (United States)

    2010-07-01T23:59:59.000Z

    Titanium clips are commonly used to delineate the location of the tumor bed during breast cancer surgery. Electron beams are frequently used to boost radiation dose to the breast cavity. This research investigated the effect on such boost treatments as a result of metallic clip perturbation potentially exhibited through attenuation and scatter processes using measurements with Gafchromic film and treatment planning simulation with both generalized Gaussian pencil beam and electron Monte Carlo algorithms. Results showed that the potential effect of clip interference is unidentifiable from both algorithms. Dosimetry with Gafchromic external beam therapy film did detect dose perturbations caused by the titanium clips in proximal plane, 0.23 mm away, resulting in 3.0% backscatter and 2.4% attenuation at 6 MeV and 2.0% backscatter and 6.7% attenuation at 9 MeV. The noise contribution of the film scanner is estimated to be about 0.4% and nearly 2% uncertainty in film calibration. As a result, we conclude that the magnitude of dose perturbations from clip is negligible for clinical findings.

  12. Microstructure of TiB{sub 2}/carbon steel surface-alloyed materials fabricated by high-energy electron beam irradiation

    SciTech Connect (OSTI)

    Euh, K. Lee, S.; Shin, K.

    1999-12-01T23:59:59.000Z

    The processing and the microstructural analysis of TiB{sub 2}/carbon steel surface-alloyed materials using the irradiation of a high-energy electron beam were investigated in this study. The mixtures of TiB{sub 2} powders and flux were deposited on a plain carbon steel substrate, and then electron beam was irradiated on these mixtures using an electron beam accelerator. The microstructure of the irradiated surface layer was composed of a melted region, an interfacial region, a coarse-grained heat-affected zone (HAZ), and a fine-grained HAZ. A few residual micropores were found in the melted region of the specimen processed without flux because of irregular thermal transfer, but their number was decreased in the specimens processed with a considerable amount of flux. As a result of irradiation, the Ti content was homogeneously maintained throughout the melted region, whose hardness was greatly improved. This was associated with the microstructural modification including the segregation of Ti and B along solidification cell boundaries and the formation of fine Ti(C, N) particles. The proper flux mix ratio was 15 to 30% to obtain excellent surface alloying and a homogeneous microstructure.

  13. Electron beam-based sources of ultrashort x-ray pulses.

    SciTech Connect (OSTI)

    Zholents, A.; Accelerator Systems Division (APS)

    2010-09-30T23:59:59.000Z

    A review of various methods for generation of ultrashort x-ray pulses using relativistic electron beam from conventional accelerators is presented. Both spontaneous and coherent emission of electrons is considered. The importance of the time-resolved studies of matter at picosecond (ps), femtosecond (fs), and atttosecond (as) time scales using x-rays has been widely recognized including by award of a Nobel Prize in 1999 [Zewa]. Extensive reviews of scientific drivers can be found in [BES1, BES2, BES3, Lawr, Whit]. Several laser-based techniques have been used to generate ultrashort x-ray pulses including laser-driven plasmas [Murn, Alte, Risc, Rose, Zamp], high-order harmonic generation [Schn, Rund, Wang, Arpi], and laser-driven anode sources [Ande]. In addition, ultrafast streak-camera detectors have been applied at synchrotron sources to achieve temporal resolution on the picosecond time scale [Wulf, Lind1]. In this paper, we focus on a different group of techniques that are based on the use of the relativistic electron beam produced in conventional accelerators. In the first part we review several techniques that utilize spontaneous emission of electrons and show how solitary sub-ps x-ray pulses can be obtained at existing storage ring based synchrotron light sources and linacs. In the second part we consider coherent emission of electrons in the free-electron lasers (FELs) and review several techniques for a generation of solitary sub-fs x-ray pulses. Remarkably, the x-ray pulses that can be obtained with the FELs are not only significantly shorter than the ones considered in Part 1, but also carry more photons per pulse by many orders of magnitude.

  14. Development of diagnostic and manipulation systems for space-charge dominated electron beams and confined electron plasmas in ELTRAP

    SciTech Connect (OSTI)

    Rome, M.; Cavaliere, F.; Maero, G.; Paroli, B.; Pozzoli, R. [INFN Sezione di Milano and Dipartimento di Fisica, Universita degli Studi di Milano, Via Celoria 16, I-20133 Milano (Italy); Cavenago, M. [INFN Laboratori Nazionali di Legnaro, Viale dell'Universita 2, I-35020 Legnaro (Italy); Ikram, M. [INFN Sezione di Milano and Dipartimento di Fisica, Universita degli Studi di Milano, Via Celoria 16, I-20133 Milano, Italy and Department of Physics, Hazara University, 21300 Mansehra (Pakistan)

    2013-03-19T23:59:59.000Z

    Modifications have been implemented in the Penning-Malmberg device ELTRAP aimed at performing studies on the dynamics of space-charge dominated nanosecond electron bunches traveling along the magnetic field. In particular, a Thomson backscattering apparatus has been developed where an infrared (IR) laser pulse collides with the bunched electron beam. The frequency-shifted backscattered radiation, acquired by means of a photomultiplier (PMT), can be exploited to evaluate information on energy, energy spread and density of the bunch. The achievable sensitivity of the diagnostics has been estimated, and valuable information on the main parameters affecting the signal-to-noise (S/N) ratio has been obtained [B. Paroli, F. Cavaliere, M. Cavenago, F. De Luca, M. Ikram, G. Maero, C. Marini, R. Pozzoli, and M. Rome, JINST 7, P01008 (2012)]. A series of upgrades are under way, aimed at increasing the S/N ratio through the use of a new laser for the electron source, the insertion of a stray light shield, and the optimization of the detection electronics. Moreover, electromagnetic simulations relevant to the design and implementation of a microwave heating system are presented. The generation of an electron plasma in ELTRAP by means of a low-power radio frequency (RF) drive in the MHz range applied on one of the trap electrodes and under ultra-high vacuum (UHV) conditions has previously been demonstrated [B. Paroli, F. De Luca, G. Maero, F. Pozzoli, and M. Rome, Plasma Sources Sci. Technol. 19, 045013 (2010)]. The new heating system will allow the extension of the RF studies to the GHz range and in particular the production of a more energetic electron plasma via cyclotron resonant excitation.

  15. Selection of dimensions for the accelerating chamber of a betatron with extraction of an electron beam

    SciTech Connect (OSTI)

    Chakhlov, V.L.; Kashovskii, V.V.; Pushin, V.S.

    1985-09-01T23:59:59.000Z

    The authors discuss the results of refinement of the dynamics of particles of a beam extracted from a betatron, a refinement which has made it possible to select the main dimensions of the accelerating chamber. Expressions are obtained which make it possible to determine the chamber dimensions and the profile of the extraction window from the distribution of the magnetic field of the betatron. It is shown that proper selection of the dimensions will increase the dose rate at the exit from the magnetic core of the accelerator.

  16. (Acceptance testing of the 150-kW electron-beam furnace)

    SciTech Connect (OSTI)

    Ohriner, E.K.; Howell, C.R.

    1990-09-18T23:59:59.000Z

    The travelers observed the acceptance testing of the 150-kW electron-beam (EB) furnace constructed by Leybold (Hanau) Technologies prior to disassembly and shipping. The testing included: (1) operation of the mold withdrawal system (2) vacuum pumping and vacuum chamber leak-up rates, (3) power stability at full power, (4) x-radiation monitoring at full power, and (5) demonstration of system interlocks for loss of water cooling, loss of vacuum, loss of power, and emergency shutdown. Preliminary training was obtained in furnace operation, EB gun maintenance, and use of the programmable logic controller for beam manipulation. Additional information was obtained on water-cooling requirements and furnace platform construction necessary for the installation. The information gained and training received will greatly assist in minimizing the installation and startup operation costs of the furnace.

  17. Si-on-Insulator formation using a line-source electron beam

    SciTech Connect (OSTI)

    Knapp, J.A.

    1984-01-01T23:59:59.000Z

    A line-source electron beam has been used to melt and recrystallize isolated Si layers to form Si-on-Insulator structures, and the process is simulated by heat flow calculations. Using sample sweep speeds of 100 to 600 cm/s and peak power densities up to 75 kW/cm/sup 2/ in the 1 x 20 mm beam, we have obtained single-crystal areas as large as 50 x 350 ..mu..m. Seed openings to the substrate are used to control the orientation of the regrowth and the heat flow in the recrystallizing film. A finite-element heat flow code has been developed which correctly simulates the experimental results and which allows the calculation of untried sample configurations.

  18. Optimizing the CEBAF Injector for Beam Operation with a Higher Voltage Electron Gun

    E-Print Network [OSTI]

    Hannon, F E; Kazimi, R

    2011-01-01T23:59:59.000Z

    Recent developments in the DC gun technology used at CEBAF have allowed an increase in operational voltage from 100kV to 130kV. In the near future this will be extended further to 200kV with the purchase of a new power supply. The injector components and layout at this time have been designed specifically for 100kV operation. It is anticipated that with an increase in gun voltage and optimization of the layout and components for 200kV operation, that the electron bunch length and beam brightness can be improved upon. This paper explores some upgrade possibilities for a 200kV gun CEBAF injector through beam dynamic simulations.

  19. Optimizing the CEBAF Injector for Beam Operation with a Higher Voltage Electron Gun

    SciTech Connect (OSTI)

    F.E. Hannon, A.S. Hofler, R. Kazimi

    2011-03-01T23:59:59.000Z

    Recent developments in the DC gun technology used at CEBAF have allowed an increase in operational voltage from 100kV to 130kV. In the near future this will be extended further to 200kV with the purchase of a new power supply. The injector components and layout at this time have been designed specifically for 100kV operation. It is anticipated that with an increase in gun voltage and optimization of the layout and components for 200kV operation, that the electron bunch length and beam brightness can be improved upon. This paper explores some upgrade possibilities for a 200kV gun CEBAF injector through beam dynamic simulations.

  20. Standing-Wave Free-Electron Laser Two-Beam Accelerator

    SciTech Connect (OSTI)

    Sessler, Andrew M.; Whittum, D.H.; Wurtele, Jonathan S.; Sharp, W.M.; Makowski, M.A.

    1991-02-01T23:59:59.000Z

    A free-electron laser (FEL) two-beam accelerator (TBA) is proposed, in which the FEL interaction takes place in a series of drive cavities, rather than in a waveguide. Each drive cavity is 'beat-coupled' to a section of the accelerating structure. This standing-wave TBA is investigated theoretically and numerically, with analyses included of microwave extraction, growth of the FEL signal through saturation, equilibrium longitudinal beam dynamics following saturation, and sensitivity of the microwave amplitude and phase to errors in current and energy. It is found that phase errors due to current jitter are substantially reduced from previous versions of the TBA. Analytic scalings and numerical simulations are used to obtain an illustrative TBA parameter set.

  1. Measurement of electron beam polarization from unstrained GaAs via two-photon photoemission

    SciTech Connect (OSTI)

    McCarter, James L. [Univ. of Virginia, Charlottesville, VA (United States); Afanasev, A. [George Washington Univ., Washingon, DC (United States); Gay, T. J. [Univ. of Nebraska, Lincoln, NE (United States); Hansknecht, John C. [JLAB, Newport News, VA (United States); Kechiantz, A. [George Washington Univ., Washingon, DC (United States); Poelker, B. Matthew [JLAB, Newport News, VA (United States)

    2014-02-01T23:59:59.000Z

    Two-photon absorption of 1560 nm light was used to generate polarized electron beams from unstrained GaAs photocathodes of varying thickness: 625 {mu}m, 0.32 {mu}m, and 0.18 {mu}m. For each photocathode, the degree of spin polarization of the photoemitted beam was less than 50%, contradicting earlier predictions based on simple quantum mechanical selection rules for spherically-symmetric systems but consistent with the more sophisticated model of Bhat et al. (Phys. Rev. B 71 (2005) 035209). Polarization via two-photon absorption was the highest from the thinnest photocathode sample and comparable to that obtained via one-photon absorption (using 778 nm light), with values 40.3 +- 1.0% and 42.6 +- 1.0%, respectively.

  2. Two Dimensional Simulation Analysis of the First Sections of a Standing-Wave Free-Electron Laser Two-Beam Accelerator

    E-Print Network [OSTI]

    Wang, C.

    2008-01-01T23:59:59.000Z

    Standing-wave free-electron laser two-beam accelerator,"of a standing-wave free electron laser," Nucl. Instr. anda standing-wave free-electron laser," Proc. SPIE Conference

  3. Electron beam processing of metals. State-of-the-art assessment. Final report

    SciTech Connect (OSTI)

    Lalwaney, N.S.

    1986-04-01T23:59:59.000Z

    Electron beam (EB)-based electrotechnologies use a high-energy electron beam as a processing tool - a stream of electrons moving at rates up to two-thirds the speed of light that can weld, melt, machine, drill, heat-treat, and cure a wide variety of materials. As a result, EB processing, mainly welding, is widely used in many industrial markets. Even though it is one of the newer electrotechnologies, its recent growth has been stable rather than spectacular, mainly due to its high initial capital costs. For many low-power applications (less than 5 to 6 kW), lasers have become a competing technology. The vacuum environment synonymous with EB technology is both a strength and a limitation of the process. The trend to automate the control of process parameters and work manipulation will continue. There will be no spectacular growth in the dollar sales of EB processing equipment, but EB processing will continue to have an important role in the metalworking and associated industries. 18 refs., 17 figs.

  4. Beam energy distribution influences on density modulation efficiency in seeded free-electron lasers

    E-Print Network [OSTI]

    Wang, Guanglei; Deng, Haixiao; Zhang, Weiqing; Wu, Guorong; Dai, Dongxu; Wang, Dong; Zhao, Zhentang; Yang, Xueming

    2015-01-01T23:59:59.000Z

    The beam energy spread at the entrance of undulator system is of paramount importance for efficient density modulation in high-gain seeded free-electron lasers (FELs). In this paper, the dependences of high harmonic micro-bunching in the high-gain harmonic generation (HGHG), echo-enabled harmonic generation (EEHG) and phase-merging enhanced harmonic generation (PEHG) schemes on the electron energy spread distribution are studied. Theoretical investigations and multi-dimensional numerical simulations are applied to the cases of uniform and saddle beam energy distributions and compared to a traditional Gaussian distribution. It shows that the uniform and saddle electron energy distributions significantly enhance the performance of HGHG-FELs, while they almost have no influence on EEHG and PEHG schemes. A numerical example demonstrates that, with about 84keV RMS uniform and/or saddle slice energy spread, the 30th harmonic radiation can be directly generated by a single-stage seeding scheme for a soft x-ray FEL f...

  5. Evaluation of a new commercial Monte Carlo dose calculation algorithm for electron beams

    SciTech Connect (OSTI)

    Vandervoort, Eric J., E-mail: evandervoort@toh.on.ca; Cygler, Joanna E. [Department of Medical Physics, The Ottawa Hospital Cancer Centre, The University of Ottawa, Ottawa, Ontario K1H 8L6 (Canada) [Department of Medical Physics, The Ottawa Hospital Cancer Centre, The University of Ottawa, Ottawa, Ontario K1H 8L6 (Canada); The Faculty of Medicine, The University of Ottawa, Ottawa, Ontario K1H 8M5 (Canada); Department of Physics, Carleton University, Ottawa, Ontario K1S 5B6 (Canada); Tchistiakova, Ekaterina [Department of Medical Physics, The Ottawa Hospital Cancer Centre, The University of Ottawa, Ottawa, Ontario K1H 8L6 (Canada) [Department of Medical Physics, The Ottawa Hospital Cancer Centre, The University of Ottawa, Ottawa, Ontario K1H 8L6 (Canada); Department of Medical Biophysics, University of Toronto, Ontario M5G 2M9 (Canada); Heart and Stroke Foundation Centre for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Ontario M4N 3M5 (Canada); La Russa, Daniel J. [Department of Medical Physics, The Ottawa Hospital Cancer Centre, The University of Ottawa, Ottawa, Ontario K1H 8L6 (Canada) and The Faculty of Medicine, The University of Ottawa, Ottawa, Ontario K1H 8M5 (Canada)] [Department of Medical Physics, The Ottawa Hospital Cancer Centre, The University of Ottawa, Ottawa, Ontario K1H 8L6 (Canada) and The Faculty of Medicine, The University of Ottawa, Ottawa, Ontario K1H 8M5 (Canada)

    2014-02-15T23:59:59.000Z

    Purpose: In this report the authors present the validation of a Monte Carlo dose calculation algorithm (XiO EMC from Elekta Software) for electron beams. Methods: Calculated and measured dose distributions were compared for homogeneous water phantoms and for a 3D heterogeneous phantom meant to approximate the geometry of a trachea and spine. Comparisons of measurements and calculated data were performed using 2D and 3D gamma index dose comparison metrics. Results: Measured outputs agree with calculated values within estimated uncertainties for standard and extended SSDs for open applicators, and for cutouts, with the exception of the 17 MeV electron beam at extended SSD for cutout sizes smaller than 5 × 5 cm{sup 2}. Good agreement was obtained between calculated and experimental depth dose curves and dose profiles (minimum number of measurements that pass a 2%/2 mm agreement 2D gamma index criteria for any applicator or energy was 97%). Dose calculations in a heterogeneous phantom agree with radiochromic film measurements (>98% of pixels pass a 3 dimensional 3%/2 mm ?-criteria) provided that the steep dose gradient in the depth direction is considered. Conclusions: Clinically acceptable agreement (at the 2%/2 mm level) between the measurements and calculated data for measurements in water are obtained for this dose calculation algorithm. Radiochromic film is a useful tool to evaluate the accuracy of electron MC treatment planning systems in heterogeneous media.

  6. Laser damage study of nodules in electron-beam-evaporated HfO{sub 2}/SiO{sub 2} high reflectors

    SciTech Connect (OSTI)

    Cheng Xinbin; Shen Zhengxiang; Jiao Hongfei; Zhang Jinlong; Ma Bin; Ding Tao; Lu Jiangtao; Wang Xiaodong; Wang Zhanshan

    2011-03-20T23:59:59.000Z

    A reactive electron beam evaporation process was used to fabricate 1.064 {mu}mHfO{sub 2}/SiO{sub 2} high reflectors. The deposition process was optimized to reduce the nodular density. Cross-sectioning of nodular defects by a focused ion-beam milling instrument showed that the nodule seeds were the residual particles on the substrate and the particulates from the silica source ''splitting.'' After optimizing the substrate preparation procedure and the evaporation process, a low nodular density of 2.7/mm{sup 2} was achieved. The laser damage test revealed that the ejection fluences and damage growth behaviors of nodules created from deep or shallow seeds were totally different. A mechanism based on directional plasma scald was proposed to interpret observed damage growth phenomenon.

  7. Terahertz free electron superradiation from mimicking surface plasmons-two electron beams interaction within a 3-mirror quasi-optical cavity

    SciTech Connect (OSTI)

    Zhang, Ya-Xin; Zhou, Y.; Dong, L.; Liu, Sheng-Gang [Terahertz Science and Technology Research Center, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)] [Terahertz Science and Technology Research Center, School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2013-05-27T23:59:59.000Z

    Interaction between mimicking surface plasmons and electron beams provides a good opportunity to develop terahertz (THz) radiation sources. In this paper, such an interaction in a special 3-mirror quasi-optical cavity is presented and explored. The 3-mirror quasi-optical cavity acts as a resonant tunable system, the resonance frequency of which can be tuned by adjusting the distance between mirrors. The study demonstrated THz free electron superradiation from the interaction of mimicking surface plasmons and two electron beams that formed a resonance within the structure, with the 3-mirror cavity enhancing the intensity of superradiation. Moreover, this system can work in the high-harmonic superradiation region with relatively high efficiency and low current density. This concept thus shows the application potential for electron-beam-driven terahertz sources.

  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. RF design of X-band RF deflector for femtosecond diagnostics of LCLS electron beam

    SciTech Connect (OSTI)

    Dolgashev, Valery A.; Wang Juwen [SLAC National Accelerator Laboratory, Menlo Park, CA, 94025 (United States)

    2012-12-21T23:59:59.000Z

    We designed a successful constant impedance traveling wave X-band rf deflector for electron beam diagnostics at the 14 GeV SLAC Linac Coherent Light Source (LCLS). This is the first practical deflector built with a waveguide coupler. The 1-meter rf deflector produces 24 MeV peak transverse kick when powered with 20 MW of 11.424 GHz rf. The design is based on our experience with high gradient X-band accelerating structures. Several deflectors of this design have been built at SLAC and are currently in use. Here we describe the design and distinguishing features of this device.

  10. Rare-earth neutral metal injection into an electron beam ion trap plasma

    SciTech Connect (OSTI)

    Magee, E. W., E-mail: magee1@llnl.gov; Beiersdorfer, P.; Brown, G. V. [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

    We have designed and implemented a neutral metal vapor injector on the SuperEBIT high-energy electron beam ion trap at the Lawrence Livermore National Laboratory. A horizontally directed vapor of a europium metal is created using a thermal evaporation technique. The metal vapor is then spatially collimated prior to injection into the trap. The source's form and quantity constraints are significantly reduced making plasmas out of metal with vapor pressures ?10{sup ?7} Torr at ?1000?°C more obtainable. A long pulsed or constant feed metal vapor injection method adds new flexibility by varying the timing of injection and rate of material being introduced into the trap.

  11. Reduced low frequency noise in electron beam evaporated MgO magnetic tunnel junctions

    SciTech Connect (OSTI)

    Diao, Z.; Feng, J. F.; Kurt, H.; Feng, G.; Coey, J. M. D. [CRANN and School of Physics, Trinity College, Dublin 2 (Ireland)

    2010-05-17T23:59:59.000Z

    We compare low frequency noise in magnetic tunnel junctions with MgO barriers prepared by electron-beam evaporation with those prepared by radiofrequency sputtering, both showing a high tunneling magnetoresistance. The normalized noise parameter in the parallel state of junctions with evaporated barriers is at least one order of magnitude lower than that in junctions with sputtered barriers, and exhibits a weaker bias dependence. The lowest normalized noise is in the 10{sup -11} mum{sup 2} range. A lower density of oxygen vacancies acting as charge trap states in the evaporated MgO is responsible for the lower noise.

  12. 2D electron density profile measurement in tokamak by laser-accelerated ion-beam probe

    SciTech Connect (OSTI)

    Chen, Y. H.; Yang, X. Y.; Lin, C., E-mail: linchen0812@pku.edu.cn, E-mail: cjxiao@pku.edu.cn; Wang, X. G.; Xiao, C. J., E-mail: linchen0812@pku.edu.cn, E-mail: cjxiao@pku.edu.cn [State Key Lab of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Wang, L. [Institute of Physics, Chinese Academy of Sciences, P. O. Box 603, Beijing 100190 (China); Xu, M. [Center for Fusion Science of Southwestern Institute of Physics, P. O. Box 432, Chengdu 610041 (China)

    2014-11-15T23:59:59.000Z

    A new concept of Heavy Ion Beam Probe (HIBP) diagnostic has been proposed, of which the key is to replace the electrostatic accelerator of traditional HIBP by a laser-driven ion accelerator. Due to the large energy spread of ions, the laser-accelerated HIBP can measure the two-dimensional (2D) electron density profile of tokamak plasma. In a preliminary simulation, a 2D density profile was reconstructed with a spatial resolution of about 2 cm, and with the error below 15% in the core region. Diagnostics of 2D density fluctuation is also discussed.

  13. Performance of a Tungsten-Cerium Fluoride Sampling Calorimeter in High-Energy Electron Beam Tests

    E-Print Network [OSTI]

    Becker, R; Dissertori, G; Djambazov, L; Donegà, 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.

  14. Vibrational excitation induced by electron beam and cosmic rays in normal and superconductive aluminum bars

    E-Print Network [OSTI]

    M. Bassan; B. Buonomo; G. Cavallari; E. Coccia; S. D'Antonio; V. Fafone; L. G. Foggetta; C. Ligi; A. Marini; G. Mazzitelli; G. Modestino; G. Pizzella; L. Quintieri; F. Ronga; P. Valente; S. M. Vinko

    2011-08-02T23:59:59.000Z

    We report new measurements of the acoustic excitation of an Al5056 superconductive bar when hit by an electron beam, in a previously unexplored temperature range, down to 0.35 K. These data, analyzed together with previous results of the RAP experiment obtained for T > 0.54 K, show a vibrational response enhanced by a factor 4.9 with respect to that measured in the normal state. This enhancement explains the anomalous large signals due to cosmic rays previously detected in the NAUTILUS gravitational wave detector.

  15. LBNL-57600/CBP Note-698 Initial Self-Consistent 3D Electron-Cloud Simulations of the LHC Beam with

    E-Print Network [OSTI]

    Furman, Miguel

    LBNL-57600/CBP Note-698 Initial Self-Consistent 3D Electron-Cloud Simulations of the LHC Beam with the Code WARP+POSINST J.-L. Vay , M. A. Furman, LBNL, CA, USA R. H. Cohen, A. Friedman, D. P. Grote, LLNL of electrons, especially across lattice elements, Work supported by the U.S. DOE under LLNL and LBNL contracts

  16. Patterned aluminum nanowires produced by electron beam at the surfaces of AlF3 single crystals

    E-Print Network [OSTI]

    Wang, Zhong L.

    Patterned aluminum nanowires produced by electron beam at the surfaces of AlF3 single crystals C is demonstrated for fabricating patterned aluminum nanowires in AlF3 substrate in a scanning electron microscope nanowires of different sizes. The aluminum nanowires may act as nano- interconnects for nanoelectronics

  17. 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.

  18. Final report to US Department of Energy: Cyclotron autoresonance accelerator for electron beam dry scrubbing of flue gases

    SciTech Connect (OSTI)

    Hirshfield, J.L.

    2001-05-25T23:59:59.000Z

    Several designs have been built and operated of microwave cyclotron autoresonance accelerators (CARA's) with electron beam parameters suitable for remediation of pollutants in flue gas emissions from coal-burning power plants. CARA designs have also been developed with a TW-level 10.6 micron laser driver for electron acceleration from 50 to 100 MeV, and with UHF drivers for proton acceleration to over 500 MeV. Dose requirements for reducing SO2, NOx, and particulates in flue gas emissions to acceptable levels have been surveyed, and used to optimize the design of an electron beam source to deliver this dose.

  19. Course Notes: United States Particle Accelerator School Beam Physics with Intense Space-Charge

    E-Print Network [OSTI]

    Barnard, J.J.

    2008-01-01T23:59:59.000Z

    Wiedermann, Particle Accelerator Physics, Springer-Verlag (invariants applied to accelerator physics. Remains one ofWiedemann, Particle Accelerator Physics II: Nonlinear and

  20. EBIT - Electronic Beam Ion Trap: N Divison experimental physics annual report 1995

    SciTech Connect (OSTI)

    Schneider, D. [ed.

    1996-10-01T23:59:59.000Z

    The multi-faceted research effort of the EBIT (Electron Beam Ion Trap) program in N-Division of the Physics and Space Technology Department at Lawrence Livermore National Laboratory (LLNL) continues to contribute significant results to the physical sciences from studies with low energy very highly charged heavy ions. The EBIT program attracts a number of collaborators from the US and abroad for the different projects. The collaborations are partly carried out through participating graduate students demonstrating the excellent educational capabilities at the LLNL EBIT facilities. Moreover, participants from Historically Black Colleges and Universities are engaged in the EBIT project. This report describes EBIT work for 1995 in atomic structure measurements and radiative transition probabilities, spectral diagnostics for laboratory and astrophysical plasmas, ion/surface interaction studies, electron-ion interactions studies, retrap and ion collisions, and instrumental development.