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Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
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they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


1

Disruption of Particle Detector Electronics by Beam Generated EMI  

SciTech Connect

The possibility that radio frequency beam generated electromagnetic interference (EMI) could disrupt the operation of particle detector electronics has been of some concern since the inception of short pulse electron colliders more than 30 years ago [1]. Some instances have been reported where this may have occurred but convincing evidence has not been available. This possibility is of concern for the International Linear Collider (ILC). We have conducted test beam studies demonstrating that electronics disruption does occur using the vertex detector electronics (VXD) from the SLD detector which took data at the SLC at SLAC. We present the results of those tests, and we describe the need for EMI standards for beam and detector instrumentation in the IR region at the ILC.

Bower, G.; /SLAC; Sugimoto, Y.; /KEK, Tsukuba; Sinev, N.; /Oregon U.; Arnold, R.; Woods, M.; /SLAC

2007-06-27T23:59:59.000Z

2

Characterisation of electron beams from laser-driven particle accelerators  

SciTech Connect

The development, understanding and application of laser-driven particle accelerators require accurate measurements of the beam properties, in particular emittance, energy spread and bunch length. Here we report measurements and simulations showing that laser wakefield accelerators can produce beams of quality comparable to conventional linear accelerators.

Brunetti, E.; Manahan, G. G.; Shanks, R. P.; Islam, M. R.; Ersfeld, B.; Anania, M. P.; Cipiccia, S.; Issac, R. C.; Vieux, G.; Welsh, G. H.; Wiggins, S. M.; Jaroszynski, D. A. [Physics Department, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

2012-12-21T23:59:59.000Z

3

Energy loss of proton, alpha particle, and electron beams in hafnium dioxide films  

SciTech Connect

The electronic stopping power, S, of HfO{sub 2} films for proton and alpha particle beams has been measured and calculated. The experimental data have been obtained by the Rutherford backscattering technique and cover the range of 120-900 and 120-3000 keV for proton and alpha particle beams, respectively. Theoretical calculations of the energy loss for the same projectiles have been done by means of the dielectric formalism using the Mermin energy loss function--generalized oscillator strength (MELF-GOS) model for a proper description of the HfO{sub 2} target on the whole momentum-energy excitation spectrum. At low projectile energies, a nonlinear theory based on the extended Friedel sum rule has been employed. The calculations and experimental measurements show good agreement for protons and a quite good one for alpha particles. In particular, the experimental maximums of both stopping curves (around 120 and 800 keV, respectively) are well reproduced. On the basis of this good agreement, we have also calculated the inelastic mean-free path (IMFP) and the stopping power for electrons in HfO{sub 2} films. Our results predict a minimum value of the IMFP and a maximum value of the S for electrons with energies around 120 and 190 eV, respectively.

Behar, Moni; Fadanelli, Raul C.; Nagamine, Luiz C. C. M. [Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, 91501-970 Porto Alegre, RS (Brazil); Abril, Isabel; Denton, Cristian D. [Departament de Fisica Aplicada, Universitat dAlacant, Apartat 99, E-03080 Alacant (Spain); Garcia-Molina, Rafael [Departamento de Fisica-CIOyN, Universidad de Murcia, Apartado 4021, E-30080 Murcia (Spain); Arista, Nestor R. [Division Colisiones Atomicas, Centro Atomico Bariloche, RA-8400 San Carlos de Bariloche (Argentina)

2009-12-15T23:59:59.000Z

4

Beam-Induced Multipactoring and Electron-Cloud Effects in Particle Accelerators  

E-Print Network (OSTI)

In the beam pipe of high-energy proton or positron accelerators an “electron cloud” can be generated by a variety of processes, e.g. by residual-gas ionization, by photoemission from synchrotron radiation, and, most importantly, by secondary emission via a beam-induced multipactoring process. The electron cloud commonly leads to a degradation of the beam vacuum by several orders of magnitude, to fast beam instabilities, to beam-size increases, and to fast or slow beam losses. At the Large Hadron Collider (LHC), the cloud electrons could also give rise to an additional heat load inside cold superconducting magnets. In addition to the direct heat deposition from incoherently moving electrons, a potential “magnetron effect” has been conjectured, where electrons would radiate coherently when moving in a strong magnetic field under the simultaneous influence of a beam-induced electric “wake” field that may become resonant with the cyclotron frequency. Electron-cloud effects are already being observed w...

Caspers, Friedhelm; Scandale, Walter; Zimmermann, F

2009-01-01T23:59:59.000Z

5

Electron beam induced structural evolution in Fe{sub 3}O{sub 4}/SiO{sub 2} particles: A new route to obtain movable core structures  

SciTech Connect

Graphical abstract: SiO{sub 2} hollow spheres with movable Fe{sub 3}O{sub 4} cores were obtained by exposing the Fe{sub 3}O{sub 4}/SiO{sub 2} particles to the electron beam of TEM. It is a new route to obtain movable core nanostructures. Research highlights: {yields} SiO{sub 2} hollow particles with movable Fe{sub 3}O{sub 4} cores were obtained. {yields} Irradiation of electron beam induced the structural evolution. {yields} A new route to obtain hollow particles with movable core. -- Abstract: SiO{sub 2} hollow spheres with movable Fe{sub 3}O{sub 4} core were obtained by exposing the pre-synthesized Fe{sub 3}O{sub 4}/SiO{sub 2} particles (with an adsorption interlayer of ethylene glycol) under the irradiation of electron beam inside transmission electron micrograph (TEM). In the formation process, the evaporation of adsorbed ethylene glycol and the evolution of amorphous SiO{sub 2} layer played important roles, and that should be attributed to the high temperature and trapped charges induced by the irradiation of electron beam. This work provided a new route to obtain particles with movable core structure and extended the applications of electron beam.

Lv, Baoliang [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taoyuan South Road 27th, Taiyuan, Shanxi 030001 (China)] [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taoyuan South Road 27th, Taiyuan, Shanxi 030001 (China); Xu, Yao, E-mail: xuyao@sxicc.ac.cn [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taoyuan South Road 27th, Taiyuan, Shanxi 030001 (China)] [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taoyuan South Road 27th, Taiyuan, Shanxi 030001 (China); Wu, Dong [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taoyuan South Road 27th, Taiyuan, Shanxi 030001 (China)] [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taoyuan South Road 27th, Taiyuan, Shanxi 030001 (China); Sun, Yuhan [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taoyuan South Road 27th, Taiyuan, Shanxi 030001 (China) [State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taoyuan South Road 27th, Taiyuan, Shanxi 030001 (China); Low Carbon Conversion Center, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201203 (China)

2011-06-15T23:59:59.000Z

6

Neutral particle beam intensity controller  

DOE Patents (OSTI)

The neutral beam intensity controller is based on selected magnetic defocusing of the ion beam prior to neutralization. The defocused portion of the beam is dumped onto a beam dump disposed perpendicular to the beam axis. Selective defocusing is accomplished by means of a magnetic field generator disposed about the neutralizer so that the field is transverse to the beam axis. The magnetic field intensity is varied to provide the selected partial beam defocusing of the ions prior to neutralization. The desired focused neutral beam portion passes along the beam path through a defining aperture in the beam dump, thereby controlling the desired fraction of neutral particles transmitted to a utilization device without altering the kinetic energy level of the desired neutral particle fraction. By proper selection of the magnetic field intensity, virtually zero through 100% intensity control of the neutral beam is achieved.

Dagenhart, W.K.

1984-05-29T23:59:59.000Z

7

Polarization of fast particle beams by collisional pumping  

DOE Patents (OSTI)

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.

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

1984-10-19T23:59:59.000Z

8

Electron Beam Ion Sources  

E-Print Network (OSTI)

Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviolet, visible light) from highly charged ions. This chapter gives an overview of EBIS physics, the principle of operation, and the known technical solutions. Using examples, the performance of EBISs as well as their applications in various fields of basic research, technology and medicine are discussed.

Zschornacka, G; Thorn, A

2013-01-01T23:59:59.000Z

9

Neutral particle beam intensity controller  

DOE Patents (OSTI)

A neutral beam intensity controller is provided for a neutral beam generator in which a neutral beam is established by accelerating ions from an ion source into a gas neutralizer. An amplitude modulated, rotating magnetic field is applied to the accelerated ion beam in the gas neutralizer to defocus the resultant neutral beam in a controlled manner to achieve intensity control of the neutral beam along the beam axis at constant beam energy. The rotating magnetic field alters the orbits of ions in the gas neutralizer before they are neutralized, thereby controlling the fraction of neutral particles transmitted out of the neutralizer along the central beam axis to a fusion device or the like. The altered path or defocused neutral particles are sprayed onto an actively cooled beam dump disposed perpendicular to the neutral beam axis and having a central open for passage of the focused beam at the central axis of the beamline. Virtually zero therough 100% intensity control is achieved by varying the magnetic field strength without altering the ion source beam intensity or its species yield.

Dagenhart, William K. (Oak Ridge, TN)

1986-01-01T23:59:59.000Z

10

Particle Detector / Beam Current Transformer  

E-Print Network (OSTI)

Particle Detector / Beam Current Transformer Analysis December 8, 2009 Harold G. Kirk #12;ShotSignal,A.U. Proton Bunch Number Beam Current Transformer - 17011 0 2 4 6 8 0 2 4 6 8 10 12 14 16 18 20 Integrated Transformer Pump 187829 (au) Probe 196504 (au) Ratios: Beam Current 1.046 SF 1.019 2.9% difference #12;Shot

McDonald, Kirk

11

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

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.

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

2013-01-21T23:59:59.000Z

12

A Non-Invasive Energy/Angle Diagnostic for Charged Particle Beams  

SciTech Connect

A diagnostic for charged particle beams based on Compton scattering is presented. The particular case of an electron beam is treated in detail relativistically.

Christensen, C. R.

2012-03-16T23:59:59.000Z

13

Title of Document: LONGITUDINAL CONTROL OF INTENSE CHARGED PARTICLE BEAMS  

E-Print Network (OSTI)

ABSTRACT Title of Document: LONGITUDINAL CONTROL OF INTENSE CHARGED PARTICLE BEAMS Brian Louis, accelerator facilities are demanding beams with higher quality. Applications such as Free Electron Lasers energy spread throughout the accelerator. Fluctuations in beam energy or density at the low-energy side

Anlage, Steven

14

Low Emittance Electron Beam Studies  

SciTech Connect

We have studied the properties of a low emittance electron beam produced by laser pulses incident onto an rf gun photocathode. The experiments were carried out at the A0 photoinjector at Fermilab. Such beam studies are necessary for fixing the design of new Linear Colliders as well as for the development of Free Electron Lasers. An overview of the A0 photoinjector is given in Chapter 1. In Chapter 2 we describe the A0 photoinjector laser system. A stable laser system is imperative for reliable photoinjector operation. After the recent upgrade, we have been able to reach a new level of stability in the pulse-to-pulse fluctuations of the pulse amplitude, and of the temporal and transverse profiles. In Chapter 3 we present a study of transverse emittance versus the shape of the photo-cathode drive-laser pulse. For that purpose a special temporal profile laser shaping device called a pulse-stacker was developed. In Chapter 4 we discuss longitudinal beam dynamics studies using a two macro-particle bunch; this technique is helpful in analyzing pulse compression in the magnetic chicane, as well as velocity bunching effects in the rf-gun and the 9-cell accelerating cavity. In Chapter 5 we introduce a proposal for laser acceleration of electrons. We have developed a laser functioning on the TEM*{sub 01} mode, a mode with a longitudinal electric field component which is suitable for such a process. Using this technique at energies above 40 MeV, one would be able to observe laser-based acceleration.

Tikhoplav, Rodion; /Rochester U.; ,

2006-04-01T23:59:59.000Z

15

Beam physics in future electron hadron colliders  

E-Print Network (OSTI)

High-energy electron-hadron collisions could support a rich research programme in particle and nuclear physics. Several future projects are being proposed around the world, in particular eRHIC at BNL, MEIC at TJNAF in the US, and LHeC at CERN in Europe. This paper will highlight some of the accelerator physics issues, and describe related technical developments and challenges for these machines. In particular, optics design and beam dynamics studies are discussed, including longitudinal phase space manipulation, coherent synchrotron radiation, beam-beam kink instability, ion effects, as well as mitigation measures for beam break up and for space-charge induced emittance growth, all of which could limit the machine performance. Finally, first steps are presented towards an LHeC R&D facility, which should investigate relevant beam-physics processes.

Valloni, A; Klein, M; Schulte, D; Zimmermann, F

2013-01-01T23:59:59.000Z

16

Particle beam injector system and method  

DOE Patents (OSTI)

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.

Guethlein, Gary

2013-06-18T23:59:59.000Z

17

Transport of elliptic intense charged -particle beams  

E-Print Network (OSTI)

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, ...

Zhou, J. (Jing), 1978-

2006-01-01T23:59:59.000Z

18

Direct particle acceleration by two identical crossed radially polarized laser beams  

SciTech Connect

Electrons and {alpha} particles injected midway between two ultrahigh intensity crossed laser beams of radial polarization are shown to be accelerated in vacuum to several gigaelectron volts and to have average energy gradients in excess of 150 GeV/m. A unique model of the crossing beams is suggested, which maximizes the particle energy gain and minimizes the particle-beam diffraction.

Salamin, Yousef I. [Department of Physics, American University of Sharjah, P.O. Box 26666, Sharjah (United Arab Emirates)

2010-07-15T23:59:59.000Z

19

Aerodynamic beam generator for large particles  

DOE Patents (OSTI)

A new type of aerodynamic particle beam generator is disclosed. This generator produces a tightly focused beam of large material particles at velocities ranging from a few feet per second to supersonic speeds, depending on the exact configuration and operating conditions. Such generators are of particular interest for use in additive fabrication techniques.

Brockmann, John E. (Albuquerque, NM); Torczynski, John R. (Albuquerque, NM); Dykhuizen, Ronald C. (Albuquerque, NM); Neiser, Richard A. (Albuquerque, NM); Smith, Mark F. (Albuquerque, NM)

2002-01-01T23:59:59.000Z

20

Electron beam cutting  

DOE Patents (OSTI)

A method for the cutting of holes 20 Angstroms in diameter, or lines 20 Angstroms wide in a material having positive ionic conduction by the use of a focused electron probe is described. The holes and lines are stable under ambient conditions.

Mochel, Margaret E. (Champaign, IL); Humphreys, Colin J. (Abingdon, GB2)

1985-04-02T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


21

Particle beam dynamics | Princeton Plasma Physics Lab  

NLE Websites -- All DOE Office Websites (Extended Search)

Particle beam dynamics Particle beam dynamics Subscribe to RSS - Particle beam dynamics The study of the physics of charged particle beams and the accelerators that produce them. This cross-disciplinary area intersects with fields such as plasma physics, high-energy density science, and ultra-fast lasers. Premiere issue of "Quest" magazine details PPPL's strides toward fusion energy and advances in plasma science Quest Magazine Summer 2013 Welcome to the premiere issue of Quest, the annual magazine of the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL). Read more about Premiere issue of "Quest" magazine details PPPL's strides toward fusion energy and advances in plasma science Ronald C Davidson Ronald Davidson heads PPPL research on charged particle beam dynamics and

22

Halpha with Heating by Particle Beams  

E-Print Network (OSTI)

Using 1D NLTE radiative hydrodynamics we model the influence of the particle beams on the Halpha line profile treating the beam propagation and the atmosphere evolution self-consistently. We focus on the influence of the non-thermal collisional rates and the return current. Based on our results, we propose a diagnostic method for determination of the particle beam presence in the formation regions of the Halpha line.

J. Kasparova; M. Varady; M. Karlicky; P. Heinzel; Z. Moravec

2007-03-30T23:59:59.000Z

23

Electron Beam--21st Century Food Technology  

E-Print Network (OSTI)

This publication explains electron beam irradiation technology to consumers, industry professionals and government officials. Electron beam irradiation is a method of treating food and other products for pathogens that might jeopardize food safety....

Vestal, Andy

2003-03-07T23:59:59.000Z

24

MIS-1 electron-beam ion source  

Science Journals Connector (OSTI)

The Institute of Nuclear Physics (INP) has developed and produced electron-beam multiply charged ion sources. These ion sources give the electron beam its high density in the ionization...3 A/cm2.... They produce...

V. G. Abdulmanov; N. S. Dikansky

2010-12-01T23:59:59.000Z

25

Measuring Tiny Waves with High Power Particle Beams | Princeton...  

NLE Websites -- All DOE Office Websites (Extended Search)

Measuring Tiny Waves with High Power Particle Beams American Fusion News Category: U.S. Universities Link: Measuring Tiny Waves with High Power Particle Beams...

26

Polymer surface treatment with particle beams  

DOE Patents (OSTI)

A polymer surface and near surface treatment process produced by irradiation with high energy particle beams. 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.

Stinnett, Regan W. (1033 Tramway La. NE., Albuquerque, NM 87122); VanDevender, J. Pace (7604 Lamplighter NE., Albuquerque, NM 87109)

1999-01-01T23:59:59.000Z

27

Polymer surface treatment with particle beams  

DOE Patents (OSTI)

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.

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

1999-05-04T23:59:59.000Z

28

Full Counting Statistics of Stationary Particle Beams  

E-Print Network (OSTI)

We present a general scheme for treating particle beams as many particle systems. This includes the full counting statistics and the requirements of Bose/Fermi symmetry. In the stationary limit, i.e., for longer and longer beams, the total particle number diverges, and a description in Fock space is no longer possible. We therefore extend the formalism to include stationary beams. These beams exhibit a well-defined "local" counting statistics, by which we mean the full counting statistics of all clicks falling into any given finite interval. We treat in detail a model of a source, creating particles in a fixed state, which then evolve under the free time evolution, and we determine the resulting stationary beam in the far field. In comparison to the one-particle picture we obtain a correction due to Bose/Fermi statistics, which depends on the emission rate. We also consider plane waves as stationary many particle states, and determine the distribution of intervals between successive clicks in such a beam.

J. Kiukas; A. Ruschhaupt; R. F. Werner

2011-03-07T23:59:59.000Z

29

An angular multigrid method for computing mono-energetic particle beams in Flatland  

E-Print Network (OSTI)

An angular multigrid method for computing mono-energetic particle beams in Flatland Christoph B: Beams of microscopic particles penetrating scattering background matter play an important role in several applications. The parameter choices made here are motivated by the problem of electron-beam cancer

MacLachlan, Scott

30

The Particle Beam Optics Interactive Computer Laboratory  

SciTech Connect

The Particle Beam Optics Interactive Computer Laboratory (PBO Lab) is an educational software concept to aid students and professionals in learning about charged particle beams and particle beam optical systems. The PBO Lab is being developed as a cross-platform application and includes four key elements. The first is a graphic user interface shell that provides for a highly interactive learning session. The second is a knowledge database containing information on electric and magnetic optics transport elements. The knowledge database provides interactive tutorials on the fundamental physics of charged particle optics and on the technology used in particle optics hardware. The third element is a graphical construction kit that provides tools for students to interactively and visually construct optical beamlines. The final element is a set of charged particle optics computational engines that compute trajectories, transport beam envelopes, fit parameters to optical constraints and carry out similar calculations for the student designed beamlines. The primary computational engine is provided by the third-order TRANSPORT code. Augmenting TRANSPORT is the multiple ray tracing program TURTLE and a first-order matrix program that includes a space charge model and support for calculating single particle trajectories in the presence of the beam space charge. This paper describes progress on the development of the PBO Lab.

Gillespie, George H.; Hill, Barrey W.; Brown, Nathan A.; Babcock, R. Chris; Martono, Hendy; Carey, David C. [G. H. Gillespie Associates, Inc., P.O. Box 2961, Del Mar, California 92014, United States of America (United States); G. H. Gillespie Associates, Inc., P.O. Box 2961, Del Mar, California 92014, United States of America (United States); Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, Illinois 60510 (United States)

1997-02-01T23:59:59.000Z

31

The Particle Beam Optics Interactive Computer Laboratory  

SciTech Connect

The Particle Beam Optics Interactive Computer Laboratory (PBO Lab) is an educational software concept to aid students and professionals in learning about charged particle beams and particle beam optical systems. The PBO Lab is being developed as a cross-platform application and includes four key elements. The first is a graphic user interface shell that provides for a highly interactive learning session. The second is a knowledge database containing information on electric and magnetic optics transport elements. The knowledge database provides interactive tutorials on the fundamental physics of charged particle optics and on the technology used in particle optics hardware. The third element is a graphical construction kit that provides tools for students to interactively and visually construct optical beamlines. The final element is a set of charged particle optics computational engines that compute trajectories, transport beam envelopes, fit parameters to optical constraints and carry out similar calculations for the student designed beamlines. The primary computational engine is provided by the third-order TRANSPORT code. Augmenting TRANSPORT is the multiple ray tracing program TURTLE and a first-order matrix program that includes a space charge model and support for calculating single particle trajectories in the presence of the beam space charge. This paper describes progress on the development of the PBO Lab. {copyright} {ital 1997 American Institute of Physics.}

Gillespie, G.H.; Hill, B.W.; Brown, N.A.; Babcock, R.C.; Martono, H. [G. H. Gillespie Associates, Inc., P.O. Box 2961, Del Mar, California 92014 (United States of America); Carey, D.C. [G. H. Gillespie Associates, Inc., P.O. Box 2961, Del Mar, California 92014 (United States of America)]|[Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, Illinois 60510 (United States)

1997-02-01T23:59:59.000Z

32

PARTICLE BEAM RADIOTHERAPY: CLINICAL PERSPECTIVE  

E-Print Network (OSTI)

RADIOBIOLOGY RELATING TO PARTICLE RADIOTHERAPY The rate of energy transferred by ionizing radiation along its typically have LETs in the range of 0.2 to 2.0 keV/, whereas a high LET form of radiation such as a fast radiation to the dose of particle radiation producing the same biologic endpoint. The RBE versus LET curve

Yetisgen-Yildiz, Meliha

33

Electron beam coupling to a metamaterial structure  

SciTech Connect

Microwave metamaterials have shown promise in numerous applications, ranging from strip lines and antennas to metamaterial-based electron beam driven devices. In general, metamaterials allow microwave designers to obtain electromagnetic characteristics not typically available in nature. High Power Microwave (HPM) sources have in the past drawn inspiration from work done in the conventional microwave source community. In this article, the use of metamaterials in an HPM application is considered by using an effective medium model to determine the coupling of an electron beam to a metamaterial structure in a geometry similar to that of a dielectric Cerenkov maser. Use of the effective medium model allows for the analysis of a wide range of parameter space, including the “mu-negative,”“epsilon-negative,” and “double negative” regimes of the metamaterial. The physics of such a system are modeled analytically and by utilizing the particle-in-cell code ICEPIC. For this geometry and effective medium representation, optimum coupling of the electron beam to the metamaterial, and thus the optimum microwave or RF production, occurs in the epsilon negative regime of the metamaterial. Given that HPM tubes have been proposed that utilize a metamaterial, this model provides a rapid method of characterizing a source geometry that can be used to quickly understand the basic physics of such an HPM device.

French, David M.; Shiffler, Don [Directed Energy Directorate, Air Force Research Laboratory, Albuquerque, New Mexico 87117 (United States)] [Directed Energy Directorate, Air Force Research Laboratory, Albuquerque, New Mexico 87117 (United States); Cartwright, Keith [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)] [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

2013-08-15T23:59:59.000Z

34

Rippled beam free electron laser amplifier  

DOE Patents (OSTI)

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.

Carlsten, Bruce E. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

35

Princeton Plasma Physics Lab - Particle beam dynamics  

NLE Websites -- All DOE Office Websites (Extended Search)

particle-beam-dynamics The study of particle-beam-dynamics The study of the physics of charged particle beams and the accelerators that produce them. This cross-disciplinary area intersects with fields such as plasma physics, high-energy density science, and ultra-fast lasers. en Premiere issue of "Quest" magazine details PPPL's strides toward fusion energy and advances in plasma science http://www.pppl.gov/news/2013/09/premiere-issue-quest-magazine-details-pppls-strides-toward-fusion-energy-and-advances-0

36

Carbon Fiber Damage in Particle Beam  

E-Print Network (OSTI)

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.

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

2011-01-01T23:59:59.000Z

37

Optics of electron beam in the Recycler  

SciTech Connect

Electron cooling of 8.9 GeV/c antiprotons in the Recycler ring (Fermilab) requires high current and good quality of the DC electron beam. Electron trajectories of {approx}0.2 A or higher DC electron beam have to be parallel in the cooling section, within {approx}0.2 mrad, making the beam envelope cylindrical. These requirements yielded a specific scheme of the electron transport from a gun to the cooling section, with electrostatic acceleration and deceleration in the Pelletron. Recuperation of the DC beam limits beam losses at as tiny level as {approx}0.001%, setting strict requirements on the return electron line to the Pelletron and a collector. To smooth the beam envelope in the cooling section, it has to be linear and known at the transport start. Also, strength of the relevant optic elements has to be measured with good accuracy. Beam-based optic measurements are being carried out and analyzed to get this information. They include beam simulations in the Pelletron, differential optic (beam response) measurements and simulation, beam profile measurements with optical transition radiation, envelope measurements and analysis with orifice scrapers. Current results for the first half-year of commissioning are presented. Although electron cooling is already routinely used for pbar stacking, its efficiency is expected to be improved.

Burov, Alexey V.; Kazakevich, G.; Kroc, T.; Lebedev, V.; Nagaitsev, S.; Prost, L.; Pruss, S.; Shemyakin, A.; Sutherland, M.; Tiunov, M.; Warner, A.; /Fermilab

2005-11-01T23:59:59.000Z

38

Fluctuations of Beams of Quantum Particles  

Science Journals Connector (OSTI)

A beam of noninteracting particles, bosons or fermions, is described by the superposition of stochastic wave packets. This description allows in each case (bosons or fermions) the determination of the detection process of the particles. This process is defined by the set of the p-order coincidence probability densities, a general formulation of which is given. In the case of a stationary and weak incoherent beam, these coincidence probability densities are studied thoroughly and several results are obtained. The well-known bunching effect for bosons and the "antibunching effect" for fermions are shown to come from the detection of indistinguishable particles. In the boson case, all the well-known results for thermal light are found. In the fermion case, the detection process is, under certain conditions, identical to a renewal process.

Christine Bénard

1970-11-01T23:59:59.000Z

39

A Micromachined Electron Beam Ion Source  

Science Journals Connector (OSTI)

The complete ion source consists of two parts: an RF-plasma electron source, the linked up optic which focuses the electron beam into the second part, the ionization...

G. Petzold; P. Siebert; J. Müller

2000-01-01T23:59:59.000Z

40

On a theory of two-beam mechanisms of charged particle acceleration in electrodynamic structures  

SciTech Connect

This work is devoted to the theoretical studies of two-beam mechanisms of charged particle acceleration in electronic structures. The first section continues the outline of results of theoretical studies commenced in the intermediate report and considers the two-beam scheme of acceleration in the plasma waveguide. According to this scheme the strong current relativistic electron beam (REB) excites the intensive plasma waves accelerating the electrons of the second beam. The driving beam is assumed to be density-modulated. The preliminary modulation of the driving REB is shown to enhance substantially the acceleration efficiency of relativistic electrons of the driven beam. The second section deals with the two-beam acceleration in the vacuum corrugated waveguide. According to this scheme the excitation of electromagnetic waves and acceleration of driven beam electrons by them is accomplished under different Cherenkov resonances between the particles of beams and the corrugated waveguide field. The electromagnetic field in the periodic structure is known to be the superposition of spatial harmonics. With the small depth of the periodic nonuniformity the amplitudes of these harmonics decrease fast with their number increasing. Therefore, if the driving beam is in the Cherenkov resonance with the first spatial harmonic and the driven beam is in resonance with the zero space harmonic then the force accelerating the driven beam would be considerably bigger than the force decelerating the driving beam electrons.

Ostrovsky, A.O. [Kharkov Inst. of Physics and Technology, Kharkov (Ukraine)

1993-09-01T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


41

Improving electron beam quality of the Boeing free electron laser  

Science Journals Connector (OSTI)

The successful operation of any free electron laser (FEL) is critically dependent upon electron beam quality. In a radiofrequency (rf) accelerator the micropulse or instantaneous beam emittance and peak current is established by the injector, however, it is important to maintain this beam's quality as it is accelerated and transported to the wiggler. In the past year, work has continued to enhance the electron beam of the Boeing FEL. The previous year's improvements in levelling the gun charge during the macropulse and rf power flatness were reported in the 1989 FEL conference. More recent work has concentrated upon the rf master oscillator and electron beam transport, which have lead to reduced macropulse energy spread, as well as decreased position and angle jitter. Also some electron beam diagnostics have been upgraded. The result has been lower macropulse emittance at the entrance to the wiggler.

D.H. Dowell; M.L. Laucks; A.R. Lowrey; M. Bemes; A. Currie; P. Johnson; K. McCrary; J. Adamski; D.R. Shoffstall; A.H. Lumpkin; R.L. Tokar

1991-01-01T23:59:59.000Z

42

Intense steady state electron beam generator  

DOE Patents (OSTI)

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.

Hershcovitch, Ady (Mount Sinai, NY); Kovarik, Vincent J. (Bohemia, NY); Prelec, Krsto (Setauket, NY)

1990-01-01T23:59:59.000Z

43

Big Bang Day: 5 Particles - 1. The Electron  

ScienceCinema (OSTI)

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.

None

2011-04-25T23:59:59.000Z

44

High gradient lens for charged particle beam  

DOE Patents (OSTI)

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.

Chen, Yu-Jiuan

2014-04-29T23:59:59.000Z

45

Single electron beam rf feedback free electron laser  

DOE Patents (OSTI)

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.

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

1981-02-11T23:59:59.000Z

46

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

E-Print Network (OSTI)

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

Liska, Richard

47

Simulation of Modulated Electron Beams in an Rf Electron Gun  

SciTech Connect

Computer simulations are used to investigate the evolution of longitudinal density and energy modulations of an electron beam in a linear accelerator system. This study examines the effect of initial energy spread on the modulations as the beam is accelerated in the electron gun.

Neuman, C. P. [Department of Physics, Queensborough Community College of the City University of New York, Bayside, NY 11364 (United States); O'Shea, P. G. [Department of Electrical and Computer Engineering, University of Maryland, College Park, MD 20742 (United States)

2010-11-04T23:59:59.000Z

48

Plasma-parameter measurements using neutral-particle-beam attenuation  

SciTech Connect

Intense and energetic neutral-particle-beam injection used for fueling or heating magnetically confined, controlled-fusion experimental plasmas can also provide diagnostic measurements of the plasmas. The attenuation of an atomic beam (mainly from charge-exchange and ionization interactions) when passing through a plasma gives the plasma line density. Orthogonal arrays of highly collimated detectors of the secondary-electron-emission type have been used in magnetic-mirror experiments to measure neutral-beam attenuation along chords through the plasma volume at different radial and axial positions. The radial array is used to infer the radial plasma-density profile; the axial array, to infer the axial plasma-density profile and the ion angular distribution at the plasma midplane.

Foote, J.H.; Molvik, A.W.; Turner, W.C.

1982-07-07T23:59:59.000Z

49

Broadband microwave burst produced by electron beams  

E-Print Network (OSTI)

Theoretical and experimental study of fast electron beams attracts a lot of attention in the astrophysics and laboratory. In the case of solar flares the problem of reliable beam detection and diagnostics is of exceptional importance. This paper explores the fact that the electron beams moving oblique to the magnetic field or along the field with some angular scatter around the beam propagation direction can generate microwave continuum bursts via gyrosynchrotron mechanism. The characteristics of the microwave bursts produced by beams differ from those in case of isotropic or loss-cone distributions, which suggests a new tool for quantitative diagnostics of the beams in the solar corona. To demonstrate the potentiality of this tool, we analyze here a radio burst occurred during an impulsive flare 1B/M6.7 on 10 March 2001 (AR 9368, N27W42). Based on detailed analysis of the spectral, temporal, and spatial relationships, we obtained firm evidence that the microwave continuum burst is produced by electron beams. For the first time we developed and applied a new forward fitting algorithm based on exact gyrosynchrotron formulae and employing both the total power and polarization measurements to solve the inverse problem of the beam diagnostics. We found that the burst is generated by a oblique beam in a region of reasonably strong magnetic field ($\\sim 200-300$ G) and the burst is observed at a quasi-transverse viewing angle. We found that the life time of the emitting electrons in the radio source is relatively short, $\\tau_l \\approx 0.5$ s, consistent with a single reflection of the electrons from a magnetic mirror at the foot point with the stronger magnetic field. We discuss the implications of these findings for the electron acceleration in flares and for beam diagnostics.

A. T. Altyntsev; G. D. Fleishman; G. -L. Huang; V. F. Melnikov

2007-12-16T23:59:59.000Z

50

Electron beam machining using rotating and shaped beam power distribution  

DOE Patents (OSTI)

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.

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

1996-01-01T23:59:59.000Z

51

Electron beam machining using rotating and shaped beam power distribution  

DOE Patents (OSTI)

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.

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

1996-07-09T23:59:59.000Z

52

Cryogenic Electron Beam Induced Chemical Etching  

Science Journals Connector (OSTI)

Cryogenic cooling is used to enable efficient, gas-mediated electron beam induced etching (EBIE) in cases where the etch rate is negligible at room and elevated substrate temperatures. The process is demonstrated using nitrogen trifluoride (NF3) as the ...

Aiden A. Martin; Milos Toth

2014-10-21T23:59:59.000Z

53

The Electron Beam Ion Source (EBIS)  

ScienceCinema (OSTI)

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

Brookhaven Lab

2010-01-08T23:59:59.000Z

54

The Electron Beam Ion Source (EBIS)  

SciTech Connect

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

Brookhaven Lab

2009-06-09T23:59:59.000Z

55

Ion beam processing of advanced electronic materials  

SciTech Connect

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)

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

56

Vacuum chamber for containing particle beams  

DOE Patents (OSTI)

A vacuum chamber for containing a charged particle beam in a rapidly changing magnetic environment comprises a ceramic pipe with conducting strips oriented along the longitudinal axis of the pipe and with circumferential conducting bands oriented perpendicular to the longitudinal axis but joined with a single longitudinal electrical connection. When both strips and bands are on the outside of the ceramic pipe, insulated from each other, a high-resistance conductive layer such as nickel can be coated on the inside of the pipe.

Harvey, A.

1985-11-26T23:59:59.000Z

57

Short rise time intense electron beam generator  

DOE Patents (OSTI)

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.

Olson, C.L.

1984-03-16T23:59:59.000Z

58

Electrons and gas versus high brightness ion beams  

E-Print Network (OSTI)

Review 1/11/05 beam Gas-Electron Source Diagnostic (GESD)and mitigation Gas-electron source diagnostic (GESD) [beam Measure each source of electrons Measure electron

2005-01-01T23:59:59.000Z

59

Holographic generation of highly twisted electron beams  

E-Print Network (OSTI)

Free electrons can possess an intrinsic orbital angular momentum, similar to those in an electron cloud, upon free-space propagation. The wavefront corresponding to the electron's wavefunction forms a helical structure with a number of twists given by the \\emph{angular speed}. Beams with a high number of twists are of particular interest because they carry a high magnetic moment about the propagation axis. Among several different techniques, electron holography seems to be a promising approach to shape a \\emph{conventional} electron beam into a helical form with large values of angular momentum. Here, we propose and manufacture a nano-fabricated phase hologram for generating a beam of this kind with an orbital angular momentum up to 200$\\hbar$. Based on a novel technique the value of orbital angular momentum of the generated beam are measured, then compared with simulations. Our work, apart from the technological achievements, may lead to a way of generating electron beams with a high quanta of magnetic momen...

Grillo, Vincenzo; Mafakheri, Erfan; Frabboni, Stefano; Karimi, Ebrahim; Boyd, Robert W

2014-01-01T23:59:59.000Z

60

Thermal equilibrium theory of periodically focused charged-particle beams  

E-Print Network (OSTI)

A thermal equilibrium theory of periodically focused charged-particle beams is presented in the framework of both warm-fluid and kinetic descriptions. In particular, the thermal beam equilibria are discussed for paraxial ...

Samokhvalova, Ksenia R

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


61

Transverse Focussing of Intense Charged Particle Beams with Chromatic...  

NLE Websites -- All DOE Office Websites (Extended Search)

Transverse Focussing of Intense Charged Particle Beams with Chromatic Effects for Heavy Ion Fusion Inventors..--.. James M. Mitrani, Igor D, Kaganovich, Ronald C, Davidson. A two...

62

SPALLATION NEUTRON SOURCE BEAM CURRENT MONITOR ELECTRONICS.  

SciTech Connect

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.

KESSELMAN, M.

2001-06-18T23:59:59.000Z

63

Electron beam diagnostic for profiling high power beams  

DOE Patents (OSTI)

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.

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

2008-03-25T23:59:59.000Z

64

Monte Carlo Modeling of Ion Beam Induced Secondary Electrons.  

E-Print Network (OSTI)

??Modeling ion beam induced secondary electron (iSE) production within matter for simulating ion beam induced images has been studied. When the complex nature of ion… (more)

Huh, Uk

2014-01-01T23:59:59.000Z

65

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

DOE Patents (OSTI)

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.

Thode, Lester E. (Los Alamos, NM)

1981-01-01T23:59:59.000Z

66

Measurements of aperture and beam lifetime using movable beam scrapers in Indus-2 electron storage ring  

SciTech Connect

In this paper, the measurements of vertical and horizontal aperture which are available for stable beam motion in Indus-2 at beam energy 2.5 GeV using movable beam scrapers are presented. These beam scrapers are installed in one of the long straight sections in the ring. With the movement of beam scrapers towards the beam centre, the beam lifetime is measured. The beam lifetime data obtained from the movement of vertical and horizontal beam scrapers are analyzed. The contribution of beam loss due to beam-gas scattering (vacuum lifetime) and electron-electron scattering within a beam bunch (Touschek lifetime) is separated from the measured beam lifetime at different positions of the beam scrapers. Vertical and horizontal beam sizes at scrapers location are estimated from the scraper movement towards the beam centre in quantum lifetime limit and their values closely agree with measured value obtained using X-ray diagnostic beamline.

Kumar, Pradeep; Ghodke, A. D.; Karnewar, A. K.; Holikatti, A. C.; Yadav, S.; Puntambekar, T. A.; Singh, G. [Raja Ramanna Centre for Advanced Technology, Indore 452013 (India)] [Raja Ramanna Centre for Advanced Technology, Indore 452013 (India); Singh, P. [Bhabha Atomic Research Centre, Mumbai (India)] [Bhabha Atomic Research Centre, Mumbai (India)

2013-12-15T23:59:59.000Z

67

Autogenerator of beams of charged particles  

DOE Patents (OSTI)

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.

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

1983-10-31T23:59:59.000Z

68

Autogenerator of beams of charged particles  

DOE Patents (OSTI)

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.

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

69

A theory of two-beam acceleration of charged particles in a plasma waveguide  

SciTech Connect

The progress made in recent years in the field of high-current relativistic electron beam (REB) generation has aroused a considerable interest in studying REB potentialities for charged particle acceleration with a high acceleration rate T = 100MeV/m. It was proposed, in particular, to employ high-current REB in two-beam acceleration schemes (TBA). In these schemes high current REB (driving beam) excites intense electromagnetic waves in the electrodynamic structure which, in their turn, accelerate particles of the other beam (driven beam). The TBA schemes can be divided into two groups. The first group includes the schemes, where the two beams (driving and driven) propagate in different electrodynamic structures coupled with each other through the waveguides which ensure the microwave power transmission to accelerate driven beam particles. The second group includes the TBA schemes, where the driving and driven beams propagate in one electrodynamic structure. The main aim of this work is to demonstrate by theory the possibility of realizing effectively the TBA scheme in the plasma waveguide. The physical model of the TBA scheme under study is formulated. A set of equations describing the excitation of RF fields by a high-current REB and the acceleration of driven beam electrons is also derived. Results are presented on the the linear theory of plasma wave amplification by the driving beam. The range of system parameters, at which the plasma-beam instability develops, is defined. Results of numerical simulation of the TBA scheme under study are also presented. The same section gives the description of the dynamics of accelerated particle bunching in the high-current REB-excited field. Estimates are given for the accelerating field intensities in the plasma and electron acceleration rates.

Ostrovsky, A.O. [Kharkov Inst. of Physics and Technology (Ukraine)

1993-11-01T23:59:59.000Z

70

Polarized electron beams at milliampere average current  

SciTech Connect

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.

Poelker, Matthew [JLAB

2013-11-01T23:59:59.000Z

71

Compact two-beam push-pull free electron laser  

DOE Patents (OSTI)

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.

Hutton, Andrew (Yorktown, VA)

2009-03-03T23:59:59.000Z

72

Title of Dissertation: CONTROL AND TRANSPORT OF INTENSE ELECTRON BEAMS  

E-Print Network (OSTI)

ABSTRACT Title of Dissertation: CONTROL AND TRANSPORT OF INTENSE ELECTRON BEAMS Hui Li, Doctor Engineering The transport of intense beams for advanced accelerator applications with high-intensity beams of beam characteristics over long distances. The University of Maryland Electron Ring (UMER), which uses

Anlage, Steven

73

Application to Particle Accelerator Beam Stabilization Glenn Decker  

NLE Websites -- All DOE Office Websites (Extended Search)

the the Measurement of Noise with Application to Particle Accelerator Beam Stabilization Glenn Decker Advanced Photon Source Accelerator Systems Division December 1998 LS-273 1 1.0 Introduction One of the most important figures of merit for a synchrotron radiation source, once speci- fied beam intensity and energy have been achieved, is charged particle beam stability. While a sig- nificant effort has been expended at the Advanced Photon Source (APS) to reduce or eliminate undesirable sources of beam motion, it will be necessary to employ active feedback to stabilize the user photon beams to the very stringent levels required. This becomes especially important when one considers that transverse beam stability is generally quoted as a fraction of beam dimensions. Since source brightness tends to be inversely proportional to these transverse dimen-

74

Susceptor heating device for electron beam brazing  

DOE Patents (OSTI)

A brazing device and method are provided which locally apply a controlled amount of heat to a selected area, within a vacuum. The device brazes two components together with a brazing metal. A susceptor plate is placed in thermal contact with one of the components. A serrated pedestal supports the susceptor plate. When the pedestal and susceptor plate are in place, an electron gun irradiates an electron beam at the susceptor plate such that the susceptor plate is sufficiently heated to transfer heat through the one component and melt the brazing metal.

Antieau, Susan M. (Pittsburgh, PA); Johnson, Robert G. R. (Trafford, PA)

1999-01-01T23:59:59.000Z

75

Electron Beam Ion Source Pre-Injector Diagnostics  

E-Print Network (OSTI)

Electron Beam Ion Source Pre-Injector Diagnostics M. Wilinski, J. Alessi, E. Beebe, S. Bellavia, A. This pre-injector is based on an Electron Beam Ion Source (EBIS), a Radio Frequency Quadrupole (RFQ, current transformer, pepperpot, electron beam ion source PACS: 29.17.+w, 29.25.Ni, 29.27.Fh INTRODUCTION

76

Comparison between direct methods for determination of microbial cell volume: electron microscopy and electronic particle sizing.  

Science Journals Connector (OSTI)

...than those processed for electronic particle sizing, reflecting...Electron Microscopy and Electronic Particle Sizing E. MONTESINOS...ofMicrobiology and Institute for Fundamental Biology, Autonomous University...transmission electron microscopy and electronic particle sizing. Statistically...

E Montesinos; I Esteve; R Guerrero

1983-05-01T23:59:59.000Z

77

Electrostatic electron cyclotron waves generated by low-energy electron beams  

E-Print Network (OSTI)

Electrostatic electron cyclotron waves generated by low-energy electron beams J. D. Menietti, O the role of electron beams with E ] 1 keV in the generation of these waves. Observed plasma parameters these waves are an indicator of the presence of low-energy electron beams and a cold electron component (E ] 0

Santolik, Ondrej

78

On the possibility of electron-beam processing of dielectrics using a forevacuum plasma electron source  

Science Journals Connector (OSTI)

An insulated target was irradiated by an electron beam generated by a forevacuum plasma electron source operating in the pressure range of 5– ... showed that plasma formed in the region of electron beam transport...

V. A. Burdovitsin; A. S. Klimov; E. M. Oks

2009-06-01T23:59:59.000Z

79

Electron beam directed energy device and methods of using same  

DOE Patents (OSTI)

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.

Retsky, Michael W. (Trumbull, CT)

2007-10-16T23:59:59.000Z

80

Experimental study of electron-and ion-beam properties on the BNL electron-beam ion source and comparison with theoretical models  

E-Print Network (OSTI)

Experimental study of electron- and ion-beam properties on the BNL electron-beam ion source of the BNL Test electron-beam ion source EBIS has been measured for different electron-beam currents With high electron current operation up to 10 A the BNL Test electron-beam ion source EBIS has demonstrated

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


81

Study of space charge compensation phenomena in charged particle beams  

SciTech Connect

The propagation of a charged particle beam is accompanied by the production of secondary particles created in the interaction of the beam itself with the background gas flowing in the accelerator tube. In the drift region, where the electric field of the electrodes is negligible, secondary particles may accumulate giving a plasma which shields the self-induced potential of the charged beam. This phenomenon, known as space charge compensation is a typical issue in accelerator physics, where it is usually addressed by means of 1D radial transport codes or Monte Carlo codes. The present paper describes some theoretical studies on this phenomenon, presenting a Particle in Cell-Monte Carlo (PIC-MC) Code developed ad hoc where both radial and axial confinements of secondary particles are calculated. The features of the model, offering a new insight on the problem, are described and some results discussed.

Veltri, P.; Serianni, G. [Consorzio RFX, C.so Stati Uniti 4, 35100 Padova (Italy); Cavenago, M. [INFN-LNL, Viale dell'Universita 2, 35020 Legnaro (Italy)

2012-02-15T23:59:59.000Z

82

Limits to Electron Beam Emittance from Stochastic Coulomb Interactions  

SciTech Connect

Dense electron beams can now be generated on an ultrafast timescale using laser driven photo-cathodes and these are used for a range of applications from ultrafast electron defraction to free electron lasers. Here we determine a lower bound to the emittance of an electron beam limited by fundamental stochastic Coulomb interactions.

Coleman-Smith, Christopher; Padmore, Howard A.; Wan, Weishi

2008-08-22T23:59:59.000Z

83

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

SciTech Connect

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.

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

1997-04-01T23:59:59.000Z

84

Polarized electron beams at milliampere average current  

SciTech Connect

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.

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

2013-11-07T23:59:59.000Z

85

Systems and methods of varying charged particle beam spot size  

DOE Patents (OSTI)

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.

Chen, Yu-Jiuan

2014-09-02T23:59:59.000Z

86

Observations of the filamentation of high-intensity laser-produced electron beams  

SciTech Connect

Filamented electron beams have been observed to be emitted from the rear of thin solid targets irradiated by a high-intensity short-pulse laser when there is low-density plasma present at the back of the target. These observations are consistent with a laser-generated beam of relativistic electrons propagating through the target, which is subsequently fragmented by a Weibel-like instability in the low-density plasma at the rear. These measurements are in agreement with particle-in-cell simulations and theory, since the filamentation instability is predicted to be dramatically enhanced when the electron beam density approaches that of the background plasma.

Wei, M.S.; Beg, F.N.; Dangor, A.E.; Gopal, A.; Tatarakis, M.; Krushelnick, K. [Blackett Laboratory, Imperial College London SW7 2BZ (United Kingdom); Clark, E.L.; Evans, R.G. [Blackett Laboratory, Imperial College London SW7 2BZ (United Kingdom); Plasma Physics Department, AWE plc, Aldermaston, Reading RG7 4PR (United Kingdom); Ledingham, K.W.D. [Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Plasma Physics Department, AWE plc, Aldermaston, Reading RG7 4PR (United Kingdom); McKenna, P. [Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Norreys, P.A. [Central Laser Facility, Rutherford Appleton Laboratory, Chilton, Oxon OX11 OQX (United Kingdom); Zepf, M. [Department of Physics, The Queen's University, University Road, Belfast BT7 1NN (United Kingdom)

2004-11-01T23:59:59.000Z

87

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

E-Print Network (OSTI)

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.

Scott, R H H

2015-01-01T23:59:59.000Z

88

Two-Beam Instability in Electron Cooling  

SciTech Connect

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.

Burov, Alexey V.; /Fermilab

2006-04-01T23:59:59.000Z

89

Electron beam diagnostic for space charge measurement of an ion beam  

SciTech Connect

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.

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

90

Electron Beam Emission Characteristics from Plasma Focus Devices  

Science Journals Connector (OSTI)

In this paper we observed the characteristics of the electron beam emission from our plasma focus machine filling neon argon helium and hydrogen. Rogowski coil and CCD based magnetic spectrometer were used to obtain temporal and energy distribution of electron emission. And the preliminary results of deposited FeCo thin film using electron beam from our plasma focus device were presented.

T. Zhang; A. Patran; D. Wong; S. M. Hassan; S. V. Springham; T. L. Tan; P. Lee; S. Lee; R. S. Rawat

2006-01-01T23:59:59.000Z

91

Novel Vortex Generator and Mode Converter for Electron Beams  

Science Journals Connector (OSTI)

A mode converter for electron vortex beams is described. Numerical simulations, confirmed by experiment, show that the converter transforms a vortex beam with a topological charge m=±1 into beams closely resembling Hermite-Gaussian HG10 and HG01 modes. The converter can be used as a mode discriminator or filter for electron vortex beams. Combining the converter with a phase plate turns a plane wave into modes with topological charge m=±1. This combination serves as a generator of electron vortex beams of high brilliance.

P. Schattschneider; M. Stöger-Pollach; J. Verbeeck

2012-08-22T23:59:59.000Z

92

Electron beam diagnostic system using computed tomography and an annular sensor  

DOE Patents (OSTI)

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.

Elmer, John W.; Teruya, Alan T.

2014-07-29T23:59:59.000Z

93

Nonlinear transmission line based electron beam driver  

SciTech Connect

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.

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

94

Ultrafast Diagnostics for Electron Beams from Laser Plasma Accelerators  

E-Print Network (OSTI)

for Laser Plasma Accelerators," in this proceedings, 2010.Based Laser Wakefield Accelerator Electron Beam EnergyMotion in a Laser-Plasma Accelerator," in this proceedings,

Matlis, N. H.

2011-01-01T23:59:59.000Z

95

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser....

96

Electron-beam-driven nanoscale metamaterial light sources  

Science Journals Connector (OSTI)

We show experimentally that beams of free electrons can induce light emission from nanoscale planar photonic metamaterials. Wavelengths of emitted light are determined by both the...

Adamo, Giorgio; Ou, Jun-Yu; MacDonald, Kevin; De Angelis, Francesco; Di Fabrizio, Enzo; Zheludev, Nikolay

97

High density harp or wire scanner for particle beam diagnostics  

DOE Patents (OSTI)

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.

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

1996-05-21T23:59:59.000Z

98

Quantum effects in electron beam pumped GaAs  

SciTech Connect

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.

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

99

Characterization of Bacteria by Particle Beam Mass Spectrometry  

Science Journals Connector (OSTI)

...of complex biological material is that of Meuzelaar...instrument, bulk samples of material (>10 Kg) are pyrolyzed...with minimal sample handling, from a naturally occurring...naires Disease (10). MATERIALS AND METHODS Bacteria...FIG. 1. Schematic diagram of particle beam MS...

Mahadeva P. Sinha; Robert M. Platz; Sheldon K. Friedlander; Vincent L. Vilker

1985-06-01T23:59:59.000Z

100

Beam Imaging of a High-Brightness Elliptic Electron Gun  

SciTech Connect

An innovative research program is being carried out to experimentally demonstrate a high-brightness, space-charge-dominated elliptic electron beam using a non-axisymmetric permanent magnet focusing system. Results of the fabrication, initial testing and beam imaging of an elliptic electron gun are reported.

Zhou Jing; Bemis, Thomas M.; Chen Chiping; Lawrence, Michael H. [Beam Power Technology, Inc., 5 Rolling Green Lane, Chelmsford, MA 01824 (United States)

2010-11-04T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


101

HIGH ENERGY ELECTRON BEAM (HEEB) PROCESSING OF ADVANCED MATERIALS  

E-Print Network (OSTI)

) ) HIGH ENERGY ELECTRON BEAM (HEEB) PROCESSING OF ADVANCED MATERIALS V. R. Dave*, D. L. Goodman 02143. ABSTRACT High Energy Electron Beams (HEEBs) offer a unique heat source that may be used- based processing so attractive are : in-depth energy penetration, very high average power levels, shock

Eagar, Thomas W.

102

Project Execution Plan Electron Beam Ion Source Project  

E-Print Network (OSTI)

Project Execution Plan for the Electron Beam Ion Source Project (EBIS) Project # 07-SC-02 of Nuclear Physics (SC ­ 26) Rev. 1 May 2008 #12;#12;#12;4 Project Execution Plan for the Electron Beam Ion Source Project (EBIS) Change Log Revision No. Pages Affected Effective Date Revision 0 Baseline Document

103

T-3 electron-beam-excited laser system  

SciTech Connect

A laser system specifically designed to study the kinetics of electron-beam driven systems is described. Details of the system are given along with measurements of the electron-beam uniformity and deposition in the laser medium. Some HF laser results obtained with this system are also given.

Klein, R A

1981-02-01T23:59:59.000Z

104

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Researchers at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. Interaction of the ALS electron beam with a femtosecond laser pulse as they co-propagate through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration as the laser pulse. This causes a dispersion of the electron trajectories, and the bunch develops a hole that emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. The technique allows tremendous flexibility in shaping the terahertz pulses by appropriate modulation of the laser pulse.

105

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

Tailored Terahertz Pulses from a Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Wednesday, 29 November 2006 00:00 Researchers at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. Interaction of the ALS electron beam with a femtosecond laser pulse as they co-propagate through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration as the laser pulse. This causes a dispersion of the electron trajectories, and the bunch develops a hole that emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. The technique allows tremendous flexibility in shaping the terahertz pulses by appropriate modulation of the laser pulse.

106

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Researchers at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. Interaction of the ALS electron beam with a femtosecond laser pulse as they co-propagate through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration as the laser pulse. This causes a dispersion of the electron trajectories, and the bunch develops a hole that emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. The technique allows tremendous flexibility in shaping the terahertz pulses by appropriate modulation of the laser pulse.

107

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

NLE Websites -- All DOE Office Websites (Extended Search)

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Tailored Terahertz Pulses from a Laser-Modulated Electron Beam Print Researchers at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz radiation from a relativistic electron beam modulated by a femtosecond laser. Interaction of the ALS electron beam with a femtosecond laser pulse as they co-propagate through a wiggler modulates the electron energies within a short slice of the electron bunch with about the same duration as the laser pulse. This causes a dispersion of the electron trajectories, and the bunch develops a hole that emits short pulses of temporally and spatially coherent terahertz pulses synchronized to the laser. The technique allows tremendous flexibility in shaping the terahertz pulses by appropriate modulation of the laser pulse.

108

Electron Gun For Multiple Beam Klystron Using Magnetic Focusing  

DOE Patents (OSTI)

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.

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

2004-07-27T23:59:59.000Z

109

Electrostatic particle trap for ion beam sputter deposition  

DOE Patents (OSTI)

A method and apparatus for the interception and trapping of or reflection of charged particulate matter generated in ion beam sputter deposition. The apparatus involves an electrostatic particle trap which generates electrostatic fields in the vicinity of the substrate on which target material is being deposited. The electrostatic particle trap consists of an array of electrode surfaces, each maintained at an electrostatic potential, and with their surfaces parallel or perpendicular to the surface of the substrate. The method involves interception and trapping of or reflection of charged particles achieved by generating electrostatic fields in the vicinity of the substrate, and configuring the fields to force the charged particulate material away from the substrate. The electrostatic charged particle trap enables prevention of charged particles from being deposited on the substrate thereby enabling the deposition of extremely low defect density films, such as required for reflective masks of an extreme ultraviolet lithography (EUVL) system.

Vernon, Stephen P. (Pleasanton, CA); Burkhart, Scott C. (Livermore, CA)

2002-01-01T23:59:59.000Z

110

NANOSTRUCTURE PATTERNING UNDER ENERGETIC PARTICLE BEAM IRRADIATION  

SciTech Connect

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.

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

2013-01-31T23:59:59.000Z

111

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

E-Print Network (OSTI)

Generation of mega-electron-volt electron beams by an ultrafast intense laser pulse Xiaofang Wang filamentation and beam breakup. These results suggest an approach for generating a beam of femtosecond, Me-intensity lasers has made it pos- sible to study extreme physics on a tabletop. Among the studies, the generation

Umstadter, Donald

112

Argonne Theory Institute on Production of Bright Electron Beams  

NLE Websites -- All DOE Office Websites (Extended Search)

White Paper PDF White Paper PDF Online Presentations Program PDF Reading List Note from C. Sinclair on Electron Emitters and Emission Processes PDF Attendee List PDF Argonne Theory Institute on Production of Bright Electron Beams September 22-26, 2003 Argonne National Laboratory, Argonne, IL Argonne National Laboratory recently initiated a new research program called "Theory Institute." As a part of this program, a beam physics theory week on "Production of Bright Electron Beams" will be held to review the current methods of generating high-brightness electron beams, determine what the fundamental limits are, study possible ways to improve them. Extensive discussion of issues including, but not limited to, the following: How should we quantify qualities of a beam?

113

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

E-Print Network (OSTI)

al. , Phys. Rev. ST Accel. Beams, submitted, (2010). 15. A.D . Kimura, Phys. Rev. ST Accel. Beams 13, 24. C . Jing, A .Driven by Lasers or Particle Beams C . B . Schroeder, E .

Schroeder, C. B.

2011-01-01T23:59:59.000Z

114

UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC  

SciTech Connect

to couple the THUNDER undulator to the LOASIS Lawrence Berkeley National Laboratory (LBNL) laser wakefield accelerator (LWFA). Currently the LWFA has achieved quasi-monoenergetic electron beams with energies up to 1 GeV. These ultra-short, high-peak-current, electron beams are ideal for driving a compact XUV free electron laser (FEL). Understanding the electron beam properties such as the energy spread and emittance is critical for achieving high quality light sources with high brightness. By using an insertion device such as an undulator and observing changes in the spontaneous emission spectrum, the electron beam energy spread and emittance can be measured with high precision. The initial experiments will use spontaneous emission from 1.5 m of undulator. Later experiments will use up to 5 m of undulator with a goal of a high gain, XUV FEL.

Bakeman, M.S.; Fawley, W.M.; Leemans, W. P.; Nakamura, K.; Robinson, K.E.; Schroeder, C.B.; Toth, C.

2009-05-04T23:59:59.000Z

115

Lasers, Electron Beams and New Years Resolutions | Department of Energy  

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Lasers, Electron Beams and New Years Resolutions Lasers, Electron Beams and New Years Resolutions Lasers, Electron Beams and New Years Resolutions March 2, 2011 - 3:43pm Addthis Charles Rousseaux Charles Rousseaux Senior Writer, Office of Science What are the key facts? The electron beam that powers Jefferson Lab's Free-Electron Laser pumped out a record power input of 500 kilvolts using an innovative energy-recovery system that amplifies energy with far less power. A sufficiently powerful laser could make an effective defensive weapon, as well as accurate detection and tracking. The few folks still keeping their New Year's resolutions to work out might be the first to appreciate the recent record-breaking lift by the Energy Department's Jefferson Lab. Take a steel dumbbell. Hoist it up - lift with your legs! - onto a stand. Then add another ...and another

116

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

NLE Websites -- All DOE Office Websites (Extended Search)

structure of the particles (e - e + , e - p colliders). The quality of X-rays production improved dramatically only after the electron accelerators were introduced. The...

117

E-Print Network 3.0 - accelerated electron beams Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

beams Search Powered by Explorit Topic List Advanced Search Sample search results for: accelerated electron beams Page: << < 1 2 3 4 5 > >> 1 KJKDec. 52002 Opportunities for Beam...

118

Results and analysis of the TMX electron-beam injection experiments  

SciTech Connect

Electron beams (e-beams) were injected into the Tandem Mirror Experiment (TMX) plasma in order to investigate the effect on the ion cyclotron fluctuations of the plasma. The power level of the e-beams was comparable to that of the injected neutral beams. It was found that injection of the e-beams produced no significant effect on the ion cyclotron fluctuations, the measured plasma parameters, or the particle and power flow of the plasma. The increase in bulk electron temperature and the production of mirror-confined electrons found in previous experiments in which e-beams were injected into a mirror-confined plasma were not observed in this experiment. Analysis of the regions and frequencies of wave creation and absorption within the plasma shows that the plasma density and magnetic field profiles through the plasma strongly affect the resonances encountered by the waves. The steep axial density profiles produced by neutral-beam injection in the TMX experiment are not conducive to efficient coupling of the e-beam energy to the plasma.

Poulsen, P.; Grubb, D.P.

1980-08-01T23:59:59.000Z

119

Heavy ion beam loss mechanisms at an electron-ion collider  

E-Print Network (OSTI)

There are currently several proposals to build a high-luminosity electron-ion collider, to study the spin structure of matter and measure parton densities in heavy nuclei, and to search for gluon saturation and new phenomena like the colored glass condensate. These measurements require operation with heavy-nuclei. We calculate the cross-sections for two important processes that will affect accelerator and detector operations: bound-free pair production, and Coulomb excitation of the nuclei. Both of these reactions have large cross-sections, 28-56 mb, which can lead to beam ion losses, produce beams of particles with altered charge:mass ratio, and produce a large flux of neutrons in zero degree calorimeters. The loss of beam particles limits the sustainable electron-ion luminosity to levels of several times $10^{32}/$cm$^2$/s.

Spencer R. Klein

2014-09-18T23:59:59.000Z

120

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

DOE Patents (OSTI)

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.

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

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


121

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

SciTech Connect

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.

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

122

Plasma Heating by High-Current Relativistic Electron Beams  

Science Journals Connector (OSTI)

A mechanism is proposed for the heating of a plasma with a high-current relativistic electron beam which makes essential use of the plasma return current induced by the beam. From overall energy conservation it is concluded that a large fraction of the beam energy is converted into plasma thermal energy. For reasonable parameters the heating occurs through ion sound turbulence generated by the plasma return current.

R. V. Lovelace and R. N. Sudan

1971-11-08T23:59:59.000Z

123

Active negative-index metamaterial powered by an electron beam  

E-Print Network (OSTI)

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 ...

Shapiro, Michael

124

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

E-Print Network (OSTI)

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 ...

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

2009-01-01T23:59:59.000Z

125

Electron-beam-induced absorption in quartz glasses  

Science Journals Connector (OSTI)

Electron-beam-induced absorption in quartz glasses of types KS-4V, KU-1, and Corning 7940 has been experimentally investigated in the 150-1000-nm region. Samples of optical materials...

Sergeev, P B; Zvorykin, V D; Sergeev, A P; Ermolenko, T A; Popov, S A; Pronina, M S; Turoverov, P K; Cheremisin, I I; Evlampiev, I K

2004-01-01T23:59:59.000Z

126

Relativistic electron beams detection in a dense plasma focus  

Science Journals Connector (OSTI)

Fast electron beams into a hollow anode of a small plasma focus machine (2 kJ, 4 ?F) were ... of about 10 ns width generated in the plasma focus are detected. Simultaneously, hard X-ray...

J. Pouzo; H. Acuña; M. Milanese; R. Moroso

2002-10-01T23:59:59.000Z

127

Jefferson Lab electron beam charges up | Jefferson Lab  

NLE Websites -- All DOE Office Websites (Extended Search)

as a beam with 6 billion electron volts of concentrated energy traveling at nearly the speed of light collides like a freight train into targets to give clues into how matter is...

128

Multiple electron stripping of heavy ion beams D. MUELLER,1  

E-Print Network (OSTI)

.L. WATSON,2 V. HORVAT,2 K.E. ZAHARAKIS,2 and Y. PENG2 1 Princeton University Plasma Physics Laboratory. Such beams will lose electrons while passing through background gas in the target chamber, and therefore it is necessary to assess the rate at which the charge state of the incident beam evolves on the way to the target

Kaganovich, Igor

129

A Gridded Electron Gun for a Sheet Beam Klystron  

SciTech Connect

This paper describes the development of an electron gun for a sheet beam klystron. Initially intended for accelerator applications, the gun can operate at a higher perveance than one with a cylindrically symmetric beam. Results of 2D and 3D simulations are discussed.

Read, M.E.; Miram, G.; Ives, R.L.; /Calabazas Creek Res., Saratoga; Ivanov, V.; Krasnykh, A.; /SLAC

2008-04-25T23:59:59.000Z

130

Electron-acoustic solitons in an electron-beam plasma system Matthieu Berthomiera)  

E-Print Network (OSTI)

Electron-acoustic solitons in an electron-beam plasma system Matthieu Berthomiera) Swedish Physics, Uppsala, Sweden Received 18 November 1999; accepted 16 March 2000 Electron-acoustic solitons exist in a two electron temperature plasma with ``cold'' and ``hot'' electrons and take the form

California at Berkeley, University of

131

Optical diagnosis of electron beam in the ''Pakhra'' synchroton  

SciTech Connect

This article presents results of a study of the dynamics of the electron-beam cross section in the ''Pakhra'' synchrotron with electron acceleration to 670 MeV. The observed dependence of the rms amplitudes of vertical oscillations on time in one acceleration cycle is in good agreement with radiation-damping theory. The time dependence of the horizontal beam dimension is in satisfactory agreement with theory, assuming that the initial dimension is dependent only on synchrotron oscillations.

Bashmakov, Y.A.; Karpov, V.A.; Yarov, A.S.

1985-05-01T23:59:59.000Z

132

Design and operation of the electron beam ion trap  

SciTech Connect

This report describes the basic features and operating principles of the Electron Beam Ion Trap. The differences between EBIT and other sources of highly charged ions are outlined. Its features and operating parameters are discussed. The report also explains why certain design choices were necessary and the constraints involved in building an electron beam ion trap. EBIT's evaporation cooling system is described in detail. 13 refs., 8 figs.

Vogel, D.

1990-05-30T23:59:59.000Z

133

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

E-Print Network (OSTI)

magnets from the electron source through our THUNDERa PMQ doublet from the electron source through an undulator.1 mrad rms from the electron source. ELECTRON BEAM TRANSPORT

Osterhoff, Jens

2012-01-01T23:59:59.000Z

134

Ultra-precise particle velocities in pulsed supersonic beams  

SciTech Connect

We describe an improved experimental method for the generation of cold, directed particle bunches, and the highly accurate determination of their velocities in a pulsed supersonic beam, allowing for high-resolution experiments of atoms, molecules, and clusters. It is characterized by a pulsed high pressure jet source with high brilliance and optimum repeatability, a flight distance of few metres that can be varied with a tolerance of setting of 50 {mu}m, and a precision in the mean flight time of particles of better than 10{sup -4}. The technique achieves unmatched accuracies in particle velocities and kinetic energies and also permits the reliable determination of enthalpy changes with very high precision.

Christen, Wolfgang [Institut fuer Chemie, Humboldt-Universitaet zu Berlin, Brook-Taylor-Strasse 2, 12489 Berlin (Germany)

2013-07-14T23:59:59.000Z

135

Beam Line Design and Beam Physics Study of Energy Recovery Linac Free Electron Laser at Peking University  

SciTech Connect

Energy recovering linac (ERL) offers an attractive alternative for generating intense beams of charged particles by approaching the operational efficiency of a storage ring while maintaining the superior beam quality typical of a linear accelerator. In ERLs, the decelerated beam cancels the beam loading effects of the accelerated beam with high repetition rate. Therefore, ERLs can, in principle, accelerate very high average currents with only modest amounts of RF power. So the efficiency of RF power to beam is much higher. Furthermore, the energy of beam to dump is lower, so it will reduce dump radiation. With the successful experiments in large maximum-to-injection energy ratio up to 51:1 and high power FEL up to 14kW, the use of ERL, especially combining with superconducting RF technology, provides a potentially powerful new paradigm for generation of the charged particle beams used in MW FEL, synchrotron radiation sources, high-energy electron cooling devices and so on. The 3+1/2 DC-SC photo injector and two 9cell TESLA superconducting cavity for IR SASE FEL in PKU provides a good platform to achieve high average FEL with Energy Recovery. The work of this thesis is on Beam line design and Beam dynamics study of Energy Recovery Linac Free Electron Laser for Peking University. It is the upgrade of PKU facility, which is under construction. With ERL, this facility can work in CW mode, so it can operate high average beam current without RF power constraint in main linac and generate high average FEL power. Moreover, it provides a test facility to study the key technology in ERL. System parameters are optimized for PKU ERL-FEL. The oscillation FEL output power is studied with different bunch charge, transverse emittance, bunch length and energy spread. The theory of optimal RF power and Q{sub ext} with ERL and without ERL is analyzed and applied to PKU injector and linac including microphonic effect. pace charge effect in the injector and merger is studied for beam energy at ~5MeV. Simulation shows that in the 3+1/2 DC- C injector, there is a region the beam could be over focused by RF electromagnetic field and the transverse emittance in the transport line up to linac will increase instantly due to over focusing. In order to eliminate this effect on beam emittance, several solutions are investigated to avoid over focusing. This result is very important for beam loading experiment for low bunch charge operation. Meanwhile, different merger structures are compared in terms of error sensitivity and emittance increase with space charge effect. In recirculation beam line, a new symmetric 180{degree} arc structure is designed. It fulfills the achromatic condition and adjustable bunch compression. These two parameters are controlled by different Quads knob. With this novel structure, the recirculation lattice can achieve path length adjustment, bunch compression and decompression in a large range. With beamline error, the beam central orbit will deviate from the designed trajectory. An orbit correction system is optimized, which balances between cost and performance of orbit after correction at design level. Different methods are used to estimate its robustness. The BBU instability, especially multi-pass BBU imposed a potentially severe limitation to the average current that can be accelerated in an ERL. Simulation gives the harmful HOMs and predicts that the threshold average current in this machine is much higher than the possible operation current. This work is based on the existing facility in PKU, so it provides guidelines for the facility operation and upgrade in the future. The theoretical analysis of ERL requirement and FEL requirement on beam transport line and beam property paves the way for future ERL research.

Guimei Wang

2011-12-31T23:59:59.000Z

136

Space charge modeling of dense electron beams with large energy spreads  

Science Journals Connector (OSTI)

Theoretical and numerical studies of the transport in vacuum of multi-nC, multi-MeV electron beams are performed using several methods, including envelope models, a novel semianalytic approach using ellipsoidal shell decomposition, a modified electrostatic particle-in-cell method, and a point-to-point interaction model. The effects of space-charge forces on the longitudinal and transverse bunch properties are evaluated for various bunch lengths, energies, energy spreads, and charges. An evaluation of the various methods for studying space-charge effects in large energy spread, high charge beams is summarized. Examples are given for beam distributions typical of those generated by plasma-based accelerators. It is found that, for the highly correlated beams produced in the self-modulated regime, the high energy portion of the beam can gain significant energy while propagating in vacuum due to space-charge effects.

G. Fubiani; J. Qiang; E. Esarey; W. P. Leemans; G. Dugan

2006-06-22T23:59:59.000Z

137

Laser-driven deflection arrangements and methods involving charged particle beams  

DOE Patents (OSTI)

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.

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

2011-08-09T23:59:59.000Z

138

Electron beam welding of ceramic to metal using fore-vacuum plasma electron source  

Science Journals Connector (OSTI)

The possibility of creating ceramic-metal joints by electron beam welding is considered. The welding of ... range (5–20 Pa) using a plasma electron source. The structure and composition of the ceramic ... breakin...

A. K. Goreev; V. A. Burdovitsin; A. S. Klimov…

2012-09-01T23:59:59.000Z

139

Note: Characteristic beam parameter for the line electron gun  

SciTech Connect

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.

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

140

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

DOE Patents (OSTI)

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.

Thode, Lester E. (Los Alamos, NM)

1981-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


141

Undergraduate Research at Jefferson Lab - Determining Electron Beam Energy  

NLE Websites -- All DOE Office Websites (Extended Search)

Pretzelosity Distribution Pretzelosity Distribution Previous Project (Pretzelosity Distribution) Undergraduate Research Main Index Next Project (Buffered Chemical Polishing) Buffered Chemical Polishing Determining Electron Beam Energy through Spin Precession Methods Student: Gina Mayonado School: McDaniel College Mentored By: Douglas Higinbotham Nuclear physics experiments at Jefferson Lab require that the beam energy of the Continuous Electron Beam Accelerator Facility (CEBAF) accelerator be known to 0.01%. The g-2 spin precession of the electrons as they circulate in the machine can be used to determine the beam energy without relying on the absolute calibration of magnets and devices required for other methods. The precision of this approach needed to be fully investigated. Spin precession methods were investigated by writing an Apple application to

142

Electron cyclotron beam measurement system in the Large Helical Device  

SciTech Connect

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.

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

143

Interaction for solitary waves in coasting charged particle beams  

SciTech Connect

By using the extended Poincare-Lighthill-Kuo perturbation method, the collision of solitary waves in a coasting charged particle beams is studied. The results show that the system admits a solution with two solitary waves, which move in opposite directions and can be described by two Korteweg-deVries equation in small-amplitude limit. The collision of two solitary waves is elastic, and after the interaction they preserve their original properties. Then the weak phase shift in traveling direction of collision between two solitary waves is derived explicitly.

Liu, Shi-Wei; Hong, Xue-Ren; Shi, Yu-Ren; Duan, Wen-shan, E-mail: duanws@nwnu.edu.cn [College of Physics and Electronic Engineering and Joint Laboratory of Atomic an Molecular Physics of NWNU and IMPCAS, Northwest Normal University, Lanzhou 730070 (China)] [College of Physics and Electronic Engineering and Joint Laboratory of Atomic an Molecular Physics of NWNU and IMPCAS, Northwest Normal University, Lanzhou 730070 (China); Qi, Xin; Yang, Lei, E-mail: lyang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)] [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Han, Jiu-Ning [College of Physics and Electromechanical Engineering, Hexi University, Zhangye 734000 (China)] [College of Physics and Electromechanical Engineering, Hexi University, Zhangye 734000 (China)

2014-03-15T23:59:59.000Z

144

Simulation of Electron Beam Irradiation of a Skin Tissue Model  

NLE Websites -- All DOE Office Websites (Extended Search)

Electron Beam Irradiation of a Skin Tissue Model Electron Beam Irradiation of a Skin Tissue Model John Miller 1 , Seema Varma 1 , William Chrisler 2 , Xihai Wang 2 and Marianne Sowa 2 1 Washington State University Tri-Cities, Richland, WA 2 Pacific Northwest National Laboratory, Richland, WA Monte Carlo simulations of electrons stopping in liquid water are being used to model electron- beam irradiation of the full-thickness (FT) EpiDerm TM skin model (MatTek, Ashland, VA). This 3D tissue model has a fully developed basement membrane separating an epidermal layer of keratinocytes from a dermal layer of fibroblasts embedded in collagen. The simulations have shown the feasibility of exposing the epidermal layer to low linear-energy-transfer (LET) radiation in the presence of a non-irradiated dermal layer (Miller et al. 2011). The variable-

145

Electron beam induced radio emission from ultracool dwarfs  

E-Print Network (OSTI)

We present the numerical simulations for an electron-beam-driven and loss-cone-driven electron-cyclotron maser (ECM) with different plasma parameters and different magnetic field strengths for a relatively small region and short time-scale in an attempt to interpret the recent discovered intense radio emission from ultracool dwarfs. We find that a large amount of electromagnetic field energy can be effectively released from the beam-driven ECM, which rapidly heats the surrounding plasma. A rapidly developed high-energy tail of electrons in velocity space (resulting from the heating process of the ECM) may produce the radio continuum depending on the initial strength of the external magnetic field and the electron beam current. Both significant linear polarization and circular polarization of electromagnetic waves can be obtained from the simulations. The spectral energy distributions of the simulated radio waves show that harmonics may appear from 10 to 70$\

Yu, S; Kuznetsov, A; Hallinan, G; Antonova, A; MacKinnon, A L; Golden, A

2012-01-01T23:59:59.000Z

146

Applied Physics B28, 2/3 239 cw Ion Lasers Pumpedby Electron Beams  

E-Print Network (OSTI)

Applied Physics B28, 2/3 239 cw Ion Lasers Pumpedby Electron Beams J. J. Rocca, J. D. Meyer, Zeng, and As by exciting He metal-vapor mixtures with a dc electron beam. The beam is generated by glow discharge electron obtained using electron beam excitation. The conventional manner of exciting cw ion lasers is to use

Rocca, Jorge J.

147

Means and method for the focusing and acceleration of parallel beams of charged particles  

DOE Patents (OSTI)

A novel apparatus and method for focussing beams of charged particles comprising planar arrays of electrostatic quadrupoles. The quadrupole arrays may comprise electrodes which are shared by two or more quadrupoles. Such quadrupole arrays are particularly adapted to providing strong focussing forces for high current, high brightness, beams of charged particles, said beams further comprising a plurality of parallel beams, or beamlets, each such beamlet being focussed by one quadrupole of the array. Such arrays may be incorporated in various devices wherein beams of charged particles are accelerated or transported, such as linear accelerators, klystron tubes, beam transport lines, etc.

Maschke, Alfred W. (East Moriches, NY)

1983-07-05T23:59:59.000Z

148

Electron Beam Alignment Strategy in the LCLS Undulators  

SciTech Connect

The x-ray FEL process puts very tight tolerances on the straightness of the electron beam trajectory (2 {micro}m rms) through the LCLS undulator system. Tight but less stringent tolerances of 80 {micro}m rms vertical and 140 {micro}m rms horizontally are to be met for the placement of the individual undulator segments with respect to the beam axis. The tolerances for electron beam straightness can only be met through beam-based alignment (BBA) based on electron energy variations. Conventional alignment will set the start conditions for BBA. Precision-fiducialization of components mounted on remotely adjustable girders and the use of beam-finder wires (BFW) will satisfy placement tolerances. Girder movement due to ground motion and temperature changes will be monitored continuously by an alignment monitoring system (ADS) and remotely corrected. This stabilization of components as well as the monitoring and correction of the electron beam trajectory based on BPMs and correctors will increase the time between BBA applications. Undulator segments will be periodically removed from the undulator Hall and measured to monitor radiation damage and other effects that might degrade undulator tuning.

Nuhn, H.-D.; Emma, P.J.; Gassner, G.L.; LeCocq, C.M.; Peters, E.; Ruland, R.E.; /SLAC

2007-01-03T23:59:59.000Z

149

Experimental Time Resolved Electron Beam Temperature Measurements Using Bremsstrahlung Diagnostics  

SciTech Connect

Electron beam temperature, {beta}{perpendicular} (= v{perpendicular}/v), is important to control for the development of high dose flash radiographic bremsstrahlung sources. At high voltage (> 5 MV) increasing electron beam temperature has a serious deleterious effect on dose production. The average and time resolved behavior of beam temperature was measured during radiographic experiments on the HERMES III accelerator (10 MV, 50 kA, 70 ns). A linear array of thermoluminescent dosimeters (TLDs) were used to estimate the time integrated average of beam temperature. On and off-axis photoconducting diamond (PCD) detectors were used to measure the time resolved bremsstrahlung dose rate, which is dependent on beam energy and temperature. The beam temperature can be determined by correlating PCD response with accelerator voltage and current and also by analyzing the ratio of PCD amplitudes on and off axis. This ratio is insensitive to voltage and current and thus, is more reliable than utilizing absolute dose rate. The data is unfolded using comparisons with Monte Carlo simulations to obtain absolute beam temperatures. The data taken on HERMES III show abrupt increases in {beta}{perpendicular} midway through the pulse indicating rapid onset of beam instability.

Menge, P.R.; Maenchen, J.E.; Mazarakis, M.G.; Rosenthal, S.E.

1999-06-25T23:59:59.000Z

150

Ultrafast electron beam imaging of femtosecond laser-induced plasma  

NLE Websites -- All DOE Office Websites (Extended Search)

Ultrafast electron beam imaging of femtosecond laser-induced plasma Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Title Ultrafast electron beam imaging of femtosecond laser-induced plasma dynamics Publication Type Journal Article Year of Publication 2010 Authors Li, Junjie, Xuan Wang, Zhaoyang Chen, Richard Clinite, Samuel S. Mao, Pengfei Zhu, Zhengming Sheng, Jie Zhang, and Jianming Cao Journal Journal of Applied Physics Volume 107 Issue 8 Date Published 03/2010 Keywords copper, electron beam applications, high-speed optical techniques, laser ablation, plasma diagnostics, plasma production by laser Abstract Plasma dynamics in the early stage of laser ablation of a copper target are investigated in real time by making ultrafast electron shadow images and electron deflectometry measurements. These complementary techniques provide both a global view and a local perspective of the associated transient electric field and charge expansion dynamics. The results reveal that the charge cloud above the target surface is composed predominantly of thermally ejected electrons and that it is self-expanding, with a fast front-layer speed exceeding 107 m/s. The average electric field strength of the charge cloud induced by a pump fluence of 2.2 J/cm2 is estimated to be ∼ 2.4×105 V/m.

151

Experimental procedures to mitigate electron beam induced artifacts during in situ fluid imaging of nanomaterials  

SciTech Connect

Currently there are few standardized experimental practices in the field of fluid stage transmission electron microscopy. To obtain consistency in this emerging field, a crucial step is to establish the common artifacts and electron beam-sample interactions that can occur. Recently many unintended phenomena have been observed during in situ fluid stage scanning transmission electron microscopy (STEM) experiments, including growth of crystals on the fluid stage windows, repulsion of particles from the irradiated area, bubble formation, and the loss of atomic information during prolonged imaging of individual nanoparticles. Here we provide a comprehensive review of these fluid stage artifacts, and we present new experimental evidence that sheds light on their origins in terms of experimental apparatus issues and indirect electron beam sample interactions with the fluid layer. The results here will provide a methodology for minimizing fluid stage imaging artifacts and acquiring quantitative in situ observations of nanomaterial behavior in a liquid environment.

Woehl, Taylor J.; Jungjohann, K. L.; Evans, James E.; Arslan, Ilke; Ristenpart, William D.; Browning, Nigel D.

2013-04-01T23:59:59.000Z

152

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

E-Print Network (OSTI)

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 design and the different physical mechanisms of laser-driven and beam-driven plasma acceleration

Geddes, Cameron Guy Robinson

153

Generation and focusing of electron beams with initial transverse-longitudinal correlation  

SciTech Connect

In charged particle beams, one of the roles played by space charge is to couple the transverse and longitudinal dynamics of the beam. This can lead to very complex phenomena which are generally studied using computer simulations. However, in some cases models based on phenomenological or analytic approximations can provide valuable insight into the system behavior. In this paper, we employ such approximations to investigate the conditions under which all the slices of a space charge dominated electron beam with slowly varying current could be focused to a waist with the same radius and at the same location, independent of slice current, and show that this can be accomplished approximately if the initial transverse-longitudinal correlation introduced onto the beam by the electron gun is chosen to compensate for the transverse-longitudinal correlation introduced onto the beam in the drift section. The validity of our approximations is assessed by use of progressively more realistic calculations. We also consider several design elements of electron guns that affect the initial correlations in the beams they generate.

Harris, J. R., E-mail: john.harris@colostate.edu [Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80523 (United States); Lewellen, J. W. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Poole, B. R. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2014-10-07T23:59:59.000Z

154

Tomographic determination of the power distribution in electron beams  

DOE Patents (OSTI)

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.

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

1996-01-01T23:59:59.000Z

155

Beam-dynamics Simulations for Channeling Radiation Electron Source  

Science Journals Connector (OSTI)

Abstract The intensity and the brilliance of the compact X-ray sources based on channeling radiation are strongly dependant on the electron beam quality. It was recently proposed to combine a field-emission electron source with channeling radiation through a diamond crystal to produce high-spectral-brilliance X-rays. There are two experiments in preparation at Fermilab to prove this technique. The beam energy in the two cases are 5-MeV and 40-MeV respectively. The field-emitted beams have emittance in the nanometer range when the microbunch is 25 ps long and the charge is about 2.5fC. RF guns operating at 1.3 GHz can produce trains of at least 2 × 105 microbunches. In this contribution we present beam-dymamics simulations of a the field-emission and subsequent accelerator up to the channeling-radiation target.

D. Mihalcea; C.A. Brau; B.K. Choi; W. Gabella; J.D. Jarvis; J.W. Lewellen; M. Mendenhall; P. Piot

2014-01-01T23:59:59.000Z

156

Exact kinetic theory for the instability of an electron beam in a hot magnetized plasma  

SciTech Connect

Efficiency of collective beam-plasma interaction strongly depends on the growth rates of dominant instabilities excited in the system. Nevertheless, exact calculations of the full unstable spectrum in the framework of relativistic kinetic theory for arbitrary magnetic fields and particle distributions were unknown until now. In this paper, we give an example of such a calculation answering the question whether the finite thermal spreads of plasma electrons are able to suppress the fastest growing modes in the beam-plasma system. It is shown that nonrelativistic temperatures of Maxwellian plasmas can stabilize only the oblique instabilities of relativistic beam. On the contrary, non-Maxwellian tails typically found in laboratory beam-plasma experiments are able to substantially reduce the growth rate of the dominant longitudinal modes affecting the efficiency of turbulent plasma heating.

Timofeev, I. V.; Annenkov, V. V. [Budker Institute of Nuclear Physics SB RAS, Novosibirsk, Russia Novosibirsk State University, Novosibirsk (Russian Federation)] [Budker Institute of Nuclear Physics SB RAS, Novosibirsk, Russia Novosibirsk State University, Novosibirsk (Russian Federation)

2013-09-15T23:59:59.000Z

157

Portable radiography system using a relativistic electron beam  

DOE Patents (OSTI)

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.

Hoeberling, R.F.

1987-09-22T23:59:59.000Z

158

Portable radiography system using a relativistic electron beam  

DOE Patents (OSTI)

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.

Hoeberling, Robert F. (502 Hamlin Ct., Los Alamos, NM 87544)

1990-01-01T23:59:59.000Z

159

Ultra-bright pulsed electron beam with low longitudinal emittance  

DOE Patents (OSTI)

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.

Zolotorev, Max (Oakland, CA)

2010-07-13T23:59:59.000Z

160

Single Crystal Diamond Beam Position Monitors with Radiofrequency Electronic Readout  

SciTech Connect

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.

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

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


161

A combined beta-beam and electron capture neutrino experiment  

E-Print Network (OSTI)

The next generation of long baseline neutrino experiments will aim at determining the value of the unknown mixing angle, theta_{13}, the type of neutrino mass hierarchy and the presence of CP-violation in the lepton sector. Beta-beams and electron capture experiments have been studied as viable candidates for long baseline experiments. They use a very clean electron neutrino beam from the beta-decays or electron capture decays of boosted ions. In the present article we consider an hybrid setup which combines a beta-beam with an electron capture beam by using boosted Ytterbium ions. We study the sensitivity to the CP-violating phase delta and the theta_{13} angle, the CP-discovery potential and the reach to determine the type of neutrino mass hierarchy for this type of long baseline experiment. The analysis is performed for different neutrino beam energies and baselines. Finally, we also discuss how the results would change if a better knowledge of some of the assumed parameters was achieved by the time this experiment could take place.

J. Bernabeu; C. Espinoza; C. Orme; S. Palomares-Ruiz; S. Pascoli

2009-02-27T23:59:59.000Z

162

High Resolution Particle Beam Monitoring and Ionization Counters with the Help of Single Carbon Nanotubes  

E-Print Network (OSTI)

After a short review of modern beam monitors, ionization and proportional counters and discussion on the necessity to have thinner wires, we propose and consider construction and parameters of nanotube particle beam monitors and counters

K. A. Ispirian; R. K. Ispiryan; A. T. Margarian

2009-08-18T23:59:59.000Z

163

Mechanism of runaway electron beam formation during plasma disruptions in tokamaks  

E-Print Network (OSTI)

A new physical mechanism of the formation of runaway electron (RE) beams during plasma disruptions in tokamaks is proposed. The plasma disruption is caused by strong stochastic magnetic field formed due to nonlinearly excited low-mode number magnetohydrodynamic (MHD) modes. It is conjectured that the runaway electron beam is formed in the central plasma region confined inside the intact magnetic surface located between $q=1$ and the closest low--order rational magnetic surfaces [$q=3/2$, $q=4/3$, \\dots]. It results in that runaway electron beam current has a helical nature with a predominant $m/n=1/1$ component. The thermal quench and current decay times are estimated using the collisional models for electron diffusion and ambipolar particle transport in a stochastic magnetic field, respectively. Possible mechanisms of the decay of runaway electron current due to an outward drift electron orbits and resonance interaction of high--energy electrons with the $m/n=1/1$ MHD mode are discussed.

Abdullaev, S S; Wongrach, K; Tokar, M; Koslowski, H R; Willi, O; Zeng, L

2015-01-01T23:59:59.000Z

164

Radial electron-beam-breakup transit-time oscillator  

DOE Patents (OSTI)

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.

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

1998-01-01T23:59:59.000Z

165

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

DOE Patents (OSTI)

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.

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

2011-03-08T23:59:59.000Z

166

Atomic Force and Scanning Electron Microscopy of Atmospheric Particles  

E-Print Network (OSTI)

conducted so as to characterize atmospheric aerosols from anthropogenic (pollution) and natural (sea saltAtomic Force and Scanning Electron Microscopy of Atmospheric Particles ZAHAVA BARKAY,1 * AMIT 69978, Israel KEY WORDS atmospheric aerosols; atomic force microscopy; scanning electron microscopy

Shapira, Yoram

167

Influence of nanosized semiconducting additives on the properties of energy-storage phase-change materials subjected to a high-intensity electron beam  

Science Journals Connector (OSTI)

The stability of paraffin with a different concentration of copper nanopowder (a particle size of 50 and 100 nm) against a high-intensity nanosecond electron beam is studied experimentally. It is shown that th...

G. G. Savenkov; V. A. Morozov; V. A. Bragin; V. M. Kats; A. A. Lukin

2013-07-01T23:59:59.000Z

168

Simulation of Electron Beam Irradiation of a Skin Tissue Model  

NLE Websites -- All DOE Office Websites (Extended Search)

Simulation of Electron Beam Irradiation of a Skin Tissue Model Simulation of Electron Beam Irradiation of a Skin Tissue Model John Miller Washington State University Tri-Cities Abstract Monte Carlo simulations of electrons stopping in liquid water are being used to model electronbeam irradiation of the full-thickness (FT) EpiDermTM skin model (MatTek, Ashland, VA). This 3D tissue model has a fully developed basement membrane separating an epidermal layer of keratinocytes from a dermal layer of fibroblasts embedded in collagen. The simulations have shown the feasibility of exposing the epidermal layer to low linear-energy-transfer (LET) radiation in the presence of a non-irradiated dermal layer (Miller et al. 2011). The variableenergy electron microbeam at PNNL (Sowa et al. 2005) was used as a model of device characteristics and

169

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

SciTech Connect

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.

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

170

Technical Challenges and Scientific Payoffs of Muon Beam Accelerators for Particle Physics  

E-Print Network (OSTI)

particles, all of the muon beam energy is available forfootprint. Indeed, an energy frontier Muon Collider couldaccelerating muons to even higher energies of several TeV,

Zisman, Michael S.

2008-01-01T23:59:59.000Z

171

Electrical characterization of defects introduced in n-Ge during electron beam deposition or exposure  

SciTech Connect

Schottky barrier diodes prepared by electron beam deposition (EBD) on Sb-doped n-type Ge were characterized using deep level transient spectroscopy (DLTS). Pt EBD diodes manufactured with forming gas in the chamber had two defects, E{sub 0.28} and E{sub 0.31}, which were not previously observed after EBD. By shielding the samples mechanically during EBD, superior diodes were produced with no measureable deep levels, establishing that energetic ions created in the electron beam path were responsible for the majority of defects observed in the unshielded sample. Ge samples that were first exposed to the conditions of EBD, without metal deposition (called electron beam exposure herein), introduced a number of new defects not seen after EBD with only the E-center being common to both processes. Substantial differences were noted when these DLTS spectra were compared to those obtained using diodes irradiated by MeV electrons or alpha particles indicating that very different defect creation mechanisms are at play when too little energy is available to form Frenkel pairs. These observations suggest that when EBD ions and energetic particles collide with the sample surface, inducing intrinsic non-localised lattice excitations, they modify defects deeper in the semiconductor thus rendering them observable.

Coelho, S. M. M.; Auret, F. D.; Janse van Rensburg, P. J.; Nel, J. M. [Department of Physics, University of Pretoria, Private Bag X20, Hatfield, 0028 (South Africa)

2013-11-07T23:59:59.000Z

172

Physics Reach of Electron-Capture Neutrino Beams  

E-Print Network (OSTI)

To complete the picture of neutrino oscillations two fundamental parameters need to be measured, theta13 and delta. The next generation of long baseline neutrino oscillation experiments -superbeams, betabeams and neutrino factories- indeed take aim at measuring them. Here we explore the physics reach of a new candidate: an electron-capture neutrino beam. Emphasis is made on its feasibility thanks to the recent discovery of nuclei that decay fast through electron capture, and on the interplay with a betabeam (its closest relative).

J. Bernabeu; J. Burguet-Castell; C. Espinoza; M. Lindroos

2005-10-21T23:59:59.000Z

173

Large area electron beam pumped krypton fluoride laser amplifier  

SciTech Connect

Nike is a recently completed multi-kilojoule krypton fluoride (KrF) laser that has been built to study the physics of direct drive inertial confinement fusion. This paper describes in detail both the pulsed power and optical performance of the largest amplifier in the Nike laser, the 60 cm amplifier. This is a double pass, double sided, electron beam-pumped system that amplifies the laser beam from an input of 50 J to an output of up to 5 kJ. It has an optical aperture of 60 cm {times} 60 cm and a gain length of 200 cm. The two electron beams are 60 cm high {times} 200 cm wide, have a voltage of 640 kV, a current of 540 kA, and a flat top power pulse duration of 250 ns. A 2 kG magnetic field is used to guide the beams and prevent self-pinching. Each electron beam is produced by its own Marx/pulse forming line system. The amplifier has been fully integrated into the Nike system and is used on a daily basis for laser-target experiments. {copyright} {ital 1997 American Institute of Physics.}

Sethian, J.D.; Obenschain, S.P.; Gerber, K.A.; Pawley, C.J.; Serlin, V.; Sullivan, C.A. [Plasma Physics Division, Naval Research Laboratory, Washington DC 20375 (United States)] [Plasma Physics Division, Naval Research Laboratory, Washington DC 20375 (United States); Webster, W. [Research Support Instruments, 4325-B Forbes Boulevard, Lanham, Maryland 20706 (United States)] [Research Support Instruments, 4325-B Forbes Boulevard, Lanham, Maryland 20706 (United States); Deniz, A.V.; Lehecka, T. [Science Applications International Corporation, 1710 Goodridge Drive, McLean, Virginia 22102 (United States)] [Science Applications International Corporation, 1710 Goodridge Drive, McLean, Virginia 22102 (United States); McGeoch, M.W. [PLEX Corporation, 21 Addington Road, Brookline, Massachusetts 02146 (United States)] [PLEX Corporation, 21 Addington Road, Brookline, Massachusetts 02146 (United States); Altes, R.A.; Corcoran, P.A.; Smith, I.D. [Pulse Sciences, Incorporated, 600 McCormick Street, San Leandro, California 94577 (United States)] [Pulse Sciences, Incorporated, 600 McCormick Street, San Leandro, California 94577 (United States); Barr, O.C. [Pharos Technical Enterprises, 1603 Barcelona Street, Livermore, California 94550 (United States)] [Pharos Technical Enterprises, 1603 Barcelona Street, Livermore, California 94550 (United States)

1997-06-01T23:59:59.000Z

174

In-situ determination of energy species yields of intense particle beams  

DOE Patents (OSTI)

An arrangement is provided for the in-situ determination of energy species yields of intense particle beams. The beam is directed onto a target surface of known composition, such that Rutherford backscattering of the beam occurs. The yield-energy characteristic response of the beam to backscattering from the target is analyzed using Rutherford backscattering techniques to determine the yields of energy species components of the beam.

Kugel, Henry W. (Somerset, NJ); Kaita, Robert (Englishtown, NJ)

1987-01-01T23:59:59.000Z

175

Development of a chemical dosimeter for electron beam food irradiation  

E-Print Network (OSTI)

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...

Rivadeneira, Ramiro Geovanny

2006-08-16T23:59:59.000Z

176

Risk Management Plan Electron Beam Ion Source Project  

E-Print Network (OSTI)

, with the appropriate management oversight, can establish the specific approaches to addressing the individual riskRisk Management Plan for the Electron Beam Ion Source Project (EBIS) Project # 06-SC-002 at Brookhaven National Laboratory Upton, NY For the U.S. Department of Energy Office of Science Office

177

RiS-M-2401 DOSIMETRY FOR ELECTRON BEAM APPLICATIONS  

E-Print Network (OSTI)

; ELECTRON BEAMS; HUMIDITY; IONIZING RADIATIONS; LINEAR ACCELERATORS; RADIATION DOSES; THIN FILMS. UDC 539 are developed. The wide range of energy of such accelerators (- 150 keV - 10 MeV) and their high dose rates-descriptors: ACCURACY; CALIBRATION; CALORIMETERS; CALORIMETRIC DOSEMETERS; DoSE-RESPONSE RELATIONSHIPS; DOSE RATES; DYES

178

Electron Beam Source Molecular Beam Epitaxy of AlxGal?xAs Graded Band Gap Device Structures  

Science Journals Connector (OSTI)

A new method has been developed for the growth of graded band-gap AlxGal?xAs alloys by molecular beam epitaxy which is based upon electron. beam evaporation of the Group III elements ... . The large dynamic respo...

R. J. Malik; A. F. J. Levi; B. F. Levine…

1989-01-01T23:59:59.000Z

179

Electron-Beam Microcharacterization Centers | U.S. DOE Office of Science  

Office of Science (SC) Website

Electron-Beam Microcharacterization Centers Electron-Beam Microcharacterization Centers Scientific User Facilities (SUF) Division SUF Home About User Facilities X-Ray Light Sources Neutron Scattering Facilities Nanoscale Science Research Centers Electron-Beam Microcharacterization Centers Accelerator & Detector Research & Development Principal Investigators' Meetings Scientific Highlights Construction Projects BES Home User Facilities Electron-Beam Microcharacterization Centers Print Text Size: A A A RSS Feeds FeedbackShare Page This research area supports three electron-beam microcharacterization centers, which operate as user facilities, work to develop next-generation electron-beam instrumentation, and conduct corresponding research. Operating funds are provided to enable expert scientific interaction and

180

ELECTRON-BEAM-INDUCED RADIO EMISSION FROM ULTRACOOL DWARFS  

SciTech Connect

We present the numerical simulations for an electron-beam-driven and loss-cone-driven electron-cyclotron maser (ECM) with different plasma parameters and different magnetic field strengths for a relatively small region and short timescale in an attempt to interpret the recent discovered intense radio emission from ultracool dwarfs. We find that a large amount of electromagnetic (EM) field energy can be effectively released from the beam-driven ECM, which rapidly heats the surrounding plasma. A rapidly developed high-energy tail of electrons in velocity space (resulting from the heating process of the ECM) may produce the radio continuum depending on the initial strength of the external magnetic field and the electron beam current. Both significant linear polarization and circular polarization of EM waves can be obtained from the simulations. The spectral energy distributions of the simulated radio waves show that harmonics may appear from 10 to 70{nu}{sub pe} ({nu}{sub pe} is the electron plasma frequency) in the non-relativistic case and from 10 to 600{nu}{sub pe} in the relativistic case, which makes it difficult to find the fundamental cyclotron frequency in the observed radio frequencies. A wide frequency band should therefore be covered by future radio observations.

Yu, S.; Doyle, J. G.; Kuznetsov, A. [Armagh Observatory, College Hill, Armagh BT61 9DG (United Kingdom); Hallinan, G. [California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Antonova, A. [Department of Astronomy, St. Kliment Ohridski University of Sofia, 5 James Bourchier Blvd., 1164 Sofia (Bulgaria); MacKinnon, A. L. [School of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ (United Kingdom); Golden, A., E-mail: syu@arm.ac.uk [Price Center, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY 10461 (United States)

2012-06-10T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


181

Low-intensity beam diagnostics with particle detectors  

SciTech Connect

The measure of low intensity beams at low-medium energy is one of the major challenge in beam diagnostics. This subject is of great interest for the design of accelerator-based medical and radioactive beam facilities. In this paper we discuss new developments in image-based devices to measure low-intensity beams. All the investigated devices must guarantee measurement of the total beam current and its transverse distribution. {copyright} {ital 1997 American Institute of Physics.}

Rovelli, A.; Ciavola, G.; Cuttone, G.; Finocchiaro, P.; Raia, G. [INFN-LNS, Via S. Sofia 44/A Catania, 95125 (Italy); De Martinis, C.; Giove, D. [INFN-LASA, Via F.lli Cervi 201 Segrate (Midway Islands), 20090 (Italy)

1997-01-01T23:59:59.000Z

182

Primer on Detectors and Electronics for Particle Physics Experiments  

E-Print Network (OSTI)

1 Primer on Detectors and Electronics for Particle Physics Experiments Alexander A. Grillo Santa, cyclotrons, synchrotrons, and linear accelerators. The projectiles of choice were electrons and protons of detectors used in scattering experiments and the electronics required to make them work. The different

California at Santa Cruz, University of

183

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

DOE Patents (OSTI)

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.

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

2007-01-23T23:59:59.000Z

184

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

DOE Patents (OSTI)

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.

Giedt, W.H.; Campiotti, R.

1996-01-09T23:59:59.000Z

185

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

DOE Patents (OSTI)

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.

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

1998-01-01T23:59:59.000Z

186

TRACING ELECTRON BEAMS IN THE SUN'S CORONA WITH RADIO DYNAMIC IMAGING SPECTROSCOPY  

SciTech Connect

We report observations of type III radio bursts at decimeter wavelengths (type IIIdm bursts)-signatures of suprathermal electron beams propagating in the low corona-using the new technique of radio dynamic imaging spectroscopy provided by the recently upgraded Karl G. Jansky Very Large Array. For the first time, type IIIdm bursts were imaged with high time and frequency resolution over a broad frequency band, allowing electron beam trajectories in the corona to be deduced. Together with simultaneous hard X-ray and extreme ultraviolet observations, we show that these beams emanate from an energy release site located in the low corona at a height below {approx}15 Mm, and propagate along a bundle of discrete magnetic loops upward into the corona. Our observations enable direct measurements of the plasma density along the magnetic loops, and allow us to constrain the diameter of these loops to be less than 100 km. These overdense and ultra-thin loops reveal the fundamentally fibrous structure of the Sun's corona. The impulsive nature of the electron beams, their accessibility to different magnetic field lines, and the detailed structure of the magnetic release site revealed by the radio observations indicate that the localized energy release is highly fragmentary in time and space, supporting a bursty reconnection model that involves secondary magnetic structures for magnetic energy release and particle acceleration.

Chen Bin [Department of Astronomy, University of Virginia, Charlottesville, VA 22904 (United States); Bastian, T. S. [National Radio Astronomy Observatory, Charlottesville, VA 22903 (United States); White, S. M. [Air Force Research Laboratory, Kirtland Air Force Base, New Mexico, NM (United States); Gary, D. E. [Center for Solar-Terrestrial Research, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Perley, R.; Rupen, M. [National Radio Astronomy Observatory, Socorro, NM 87801 (United States); Carlson, B. [National Research Council of Canada, Penticton, BC V2A 6J9 (Canada)

2013-01-20T23:59:59.000Z

187

Metrology for electron-beam lithography and resist contrast at the sub-10 nm scale  

E-Print Network (OSTI)

Exploring the resolution limit of electron-beam lithography is of great interest both scientifically and technologically. However, when electron-beam lithography approaches its resolution limit, imaging and metrology of ...

Duan, Huigao

188

BNL-73700-2005-IR ELECTRON BEAM ION SOURCE PRE-INJECTOR PROJECT  

E-Print Network (OSTI)

BNL-73700-2005-IR ELECTRON BEAM ION SOURCE PRE-INJECTOR PROJECT (EBIS) CONCEPTUAL DESIGN REPORT J.2. THE EBIS SOURCE .........................................................................................14 4.2. DEMONSTRATION OF HIGH CURRENT ELECTRON BEAM FORMATION AND PROPAGATION

189

Single Source Electron Beam Evaporation of Bi-Sr-Ca-Cu-O Thin Films  

Science Journals Connector (OSTI)

A modified electron beam evaporation technique for the deposition of BiSrCaCuO thin films has been developed. In contrast to the conventional hearthed electron beam crucible the design in the present study use...

M. Ghanashyam Krishna; G. K. Muralidhar…

1990-01-01T23:59:59.000Z

190

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

E-Print Network (OSTI)

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

2008-01-01T23:59:59.000Z

191

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

DOE Patents (OSTI)

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.

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

2007-10-09T23:59:59.000Z

192

Suppression of Beam-Ion Instability in Electron Rings with Multi-Bunch Train Beam Fillings  

SciTech Connect

The ion-caused beam instability in the future light sources and electron damping rings can be serious due to the high beam current and ultra-small emittance of picometer level. One simple and effective mitigation of the instability is a multi-bunch train beam filling pattern which can significantly reduce the ion density near the beam, and therefore reduce the instability growth rate up to two orders of magnitude. The suppression is more effective for high intensity beams with low emittance. The distribution and the field of trapped ions are benchmarked to validate the model used in the paper. The wake field of ion-cloud and the beam-ion instability is investigated both analytically and numerically. We derived a simple formula for the build-up of ion-cloud and instability growth rate with the multi-bunch-train filling pattern. The ion instabilities in ILC damping ring, SuperKEKB and SPEAR3 are used to compare with our analyses. The analyses in this paper agree well with simulations.

Wang, L.; Cai, Y.; Raubenheimer, T.O.; /SLAC; Fukuma, H.; /KEK, Tsukuba

2011-08-18T23:59:59.000Z

193

Effect of electron beam misalignments on the gyrotron efficiency  

SciTech Connect

The theory describing the operation of gyrotrons with tilted and shifted electron beams has been developed. Effects of the tilt and shift are studied for a 1 MW, 170 GHz gyrotron, which is presently under development in Europe for electron cyclotron resonance plasma heating and current drive in the International Thermonuclear Experimental Reactor. It is shown that one should expect significant deterioration of gyrotron operation in such gyrotrons when the tilt angle exceeds 0.4°–0.5° and the parallel shift of the beam axis with respect to the axis of a microwave circuit is larger than 0.4–0.5 mm. At the same time, simultaneous tilting and shifting in a proper manner can mitigate this deteriorating effect.

Dumbrajs, O. [Institute of Solid State Physics, University of Latvia, Kengaraga Street 8, LV-1063 Riga (Latvia)] [Institute of Solid State Physics, University of Latvia, Kengaraga Street 8, LV-1063 Riga (Latvia); Nusinovich, G. S. [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742-3511 (United States)] [Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742-3511 (United States)

2013-07-15T23:59:59.000Z

194

Analytical Solutions for the Nonlinear Longitudinal Drift Compression (Expansion) of Intense Charged Particle Beams  

SciTech Connect

To achieve high focal spot intensities in heavy ion fusion, the ion beam must be compressed longitudinally by factors of ten to one hundred before it is focused onto the target. The longitudinal compression is achieved by imposing an initial velocity profile tilt on the drifting beam. In this paper, the problem of longitudinal drift compression of intense charged particle beams is solved analytically for the two important cases corresponding to a cold beam, and a pressure-dominated beam, using a one-dimensional warm-fluid model describing the longitudinal beam dynamics.

Edward A. Startsev; Ronald C. Davidson

2004-04-09T23:59:59.000Z

195

Characterization of electron beam melted uranium - 6% niobium ingots  

SciTech Connect

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.

McKoon, R.H.

1997-10-31T23:59:59.000Z

196

Electron Beam Diagnostics using Coherent Cherenkov Radiation in Aerogel  

SciTech Connect

The use of coherent Cherenkov radiation as a diagnostic tool for longitudinal distribution of an electron beam is studied in this paper. Coherent Cherenkov radiation is produced in an aerogel with an index of refraction close to unity. An aerogel spectral properties are experimentally studied and analyzed. This method will be employed for the helical IFEL bunching experiment at Neptune linear accelerator facility at UCLA.

Tikhoplav, R.; Knyazik, A.; Rosenzweig, J. B. [UCLA Physics Dept., Los Angeles, CA 90066 (United States); Ruelas, M. [RadiaBeam Technologies, Marina Del Ray, CA 90292 (United States)

2009-01-22T23:59:59.000Z

197

Fundamental Proximity Effects in Focused electron Beam Induced Deposition  

SciTech Connect

Fundamental proximity effects for electron beam induced deposition processes on nonflat surfaces were studied experimentally and via simulation. Two specific effects were elucidated and exploited to considerably increase the volumetric growth rate of this nanoscale direct write method: (1) increasing the scanning electron pitch to the scale of the lateral electron straggle increased the volumetric growth rate by 250% by enhancing the effective forward scattered, backscattered, and secondary electron coefficients as well as by strong recollection effects of adjacent features; and (2) strategic patterning sequences are introduced to reduce precursor depletion effects which increase volumetric growth rates by more than 90%, demonstrating the strong influence of patterning parameters on the final performance of this powerful direct write technique.

Plank, Harald [Graz University of Technology; Smith, Daryl [University of Tennessee, Knoxville (UTK); Haber, Thomas [Graz University of Technology; Rack, Philip D [ORNL; Hofer, Ferdinand [Graz University of Technology

2012-01-01T23:59:59.000Z

198

Optical and electrical characterization of the electron beam gun evaporated TiO2 lm  

E-Print Network (OSTI)

Optical and electrical characterization of the electron beam gun evaporated TiO2 ®lm V of TiO2 ®lms obtained by electron beam gun evaporation and annealed in an oxygen environment. A negative with TiO2 insulator ®lms deposited by electron beam gun evaporator. P-type Si wafers (1 0 0 orientation

Eisenstein, Gadi

199

Structural properties and electrical characteristics of electron-beam gun evaporated erbium oxide films  

E-Print Network (OSTI)

Structural properties and electrical characteristics of electron-beam gun evaporated erbium oxide for publication 3 January 2002 We report properties of Er2O3 films deposited on silicon using electron-beam gun to 700 °C.6 The Er2O3 films we describe were deposited by an electron-beam gun EBG evaporation system

Eisenstein, Gadi

200

Electrical characteristics of Ta2O5 thin films deposited by electron beam gun evaporation  

E-Print Network (OSTI)

Electrical characteristics of Ta2O5 thin films deposited by electron beam gun evaporation V films deposited by a simple electron beam gun evaporator. We describe thicknessO5 thin films deposited by a simple electron beam gun evaporator which enables versatility

Eisenstein, Gadi

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


201

Plasma diagnostics by means of the scattering of electrons and proton beams  

E-Print Network (OSTI)

Plasma diagnostics by means of the scattering of electrons and proton beams E. NARDI,1 Y. MARON,1; ACCEPTED 23 May 2007) Abstract Scattering of energetic electron and proton beams by cold matter this effect as a plasma diagnostic tool, utilizing monoenergetic, well-collimated electron or proton beams

202

CONTROLS AND DIAGNOSTICS FOR THE HIGH CURRENT ELECTRON BEAM ION SOURCE AT BNL *  

E-Print Network (OSTI)

CONTROLS AND DIAGNOSTICS FOR THE HIGH CURRENT ELECTRON BEAM ION SOURCE AT BNL * E. Beebe, J Test Stand (EBTS), is a full electron beam power, half ion trap length prototype for an Electron Beam Ion Source (EBIS) that could meet requirements for the Relativistic Heavy Ion Collider (RHIC

203

Measurement of energy deposited by charged-particle beams in composite targets  

SciTech Connect

We have measured the energy deposited in two types of composite targets by a number of charged-particle beams: targets made of /sup 238/U, Lucite, and polyethylene were exposed to 0.26-GeV protons and 0.33-GeV deuterons, and aluminum-Lucite composites were exposed to 0.5-GeV electrons. In addition, we measured neutrons and gamma rays emitted from solid targets of various materials (including /sup 238/U and iron) exposed to 0.26-GeV protons and 0.33-GeV deuterons. We used passive detectors (thermoluminescence dosimeters, Lexan fission track recorders, and photographic emulsions) to measure the nonfission dose and the fission-fragment dose from the primary beam and its shower of products. Measurements were made at various depths and radial positions in the targets. Plots and numerical values of the measured doses are presented. The emission of neutrons and gamma rays was measured with a liquid-deuterated-benzene detector. In general, the dose profile with depth is similar for 0.26-GeV protons and 0.33-GeV deuterons. The ratio of return neutrons to gamma rays increases with increasing target mass number. Deuterons, however, produce from 1.7 to 5.8 times as many neutrons and gamma rays per particle as do protons.

Farley, E.; Becker, J.; Crase, K.; Howe, R.; Selway, D.

1980-07-02T23:59:59.000Z

204

Ion Beam Collimation For Improved Resolution In Associated Particle Imaging  

SciTech Connect

Beam spot size on target for a Penning ion source has been measured under different source operating pressures as a function of the extraction channel length and beam energy. A beam halo/core structure was observed for ion extraction at low extraction voltages, and was greatly reduced at higher beam energy. Collimation through use of longer extraction channels results in reduced ion current on target; the resultant reduction in neutron yield for an API system driven by such an ion source can be compensated for by use of even higher beam energies.

Sy, Amy [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Department of Nuclear Engineering, University of California, Berkeley, Berkeley, CA 94720 (United States); Ji Qing [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States)

2011-06-01T23:59:59.000Z

205

Particle-in-Cell Simulations with Kinetic Electrons  

Science Journals Connector (OSTI)

A new scheme, based on an exact separation between adiabatic and nonadiabatic electron responses, for particle-in-cell (PIC) simulations of drift-type modes is presented. The (linear and nonlinear) elliptic equations for the scalar fields are solved ... Keywords: drift-waves, multigrid, particle-in-cell, turbulence

J. L. V. Lewandowski

2004-10-01T23:59:59.000Z

206

Nanotube diameter optimal for channeling of high-energy particle beam  

E-Print Network (OSTI)

Channeling of particle beam in straight and bent single-wall nanotubes has been studied in computer simulations. We have found that the nanotubes should be sufficiently narrow in order to steer efficiently the particle beams, with preferred diameter in the order of 0.5-2 nm. Wider nanotubes, e.g. 10-50 nm, appear rather useless for channeling purpose because of high sensitivity of channeling to nanotube curvature. We have compared bent nanotubes with bent crystals as elements of beam steering technique, and found that narrow nanotubes have an efficiency of beam bending similar to that of crystals.

V. M. Biryukov; S. Bellucci

2002-06-04T23:59:59.000Z

207

A low emittance, flat-beam electron source for linear colliders  

Science Journals Connector (OSTI)

We present a method to generate a flat (large horizontal to vertical emittance ratio) electron beam suitable for linear colliders. The concept is based on a round-beam rf photoinjector with finite solenoid field at the cathode together with a special beam optics adapter. Computer simulations of this new type of beam source show that the beam quality required for a linear collider may be obtainable without the need for an electron damping ring.

R. Brinkmann; Y. Derbenev; K. Flöttmann

2001-05-18T23:59:59.000Z

208

Testing General Relativity With Laser Accelerated Electron Beams  

E-Print Network (OSTI)

Electron accelerations of the order of $10^{21} g$ obtained by laser fields open up the possibility of experimentally testing one of the cornerstones of general relativity, the weak equivalence principle, which states that the local effects of a gravitational field are indistinguishable from those sensed by a properly accelerated observer in flat space-time. We illustrate how this can be done by solving the Einstein equations in vacuum and integrating the geodesic equations of motion for a uniformly accelerated particle.

L. Á. Gergely; T. Harko

2012-07-16T23:59:59.000Z

209

Testing general relativity with laser accelerated electron beams  

SciTech Connect

Electron accelerations of the order of 10{sup 21} g obtained by laser fields open up the possibility of experimentally testing one of the cornerstones of general relativity, the weak equivalence principle, which states that the local effects of a gravitational field are indistinguishable from those sensed by a properly accelerated observer in flat space-time. We illustrate how this can be done by solving the Einstein equations in vacuum and integrating the geodesic equations of motion for a uniformly accelerated particle.

Gergely, L. A.; Harko, T. [Department of Theoretical Physics, University of Szeged, Szeged 6720, Tisza L. krt. 84, Hungary and Department of Experimental Physics, University of Szeged, 6720 Szeged, Dom ter 9 (Hungary); Department of Physics and Center for Theoretical and Computational Physics, University of Hong Kong, Pok Fu Lam Road (Hong Kong)

2012-07-09T23:59:59.000Z

210

Three-dimensional manipulation of electron beam phase space for seeding soft x-ray free-electron lasers  

E-Print Network (OSTI)

In this letter, a simple technique is proposed to induce strong density modulation into the electron beam with small energy modulation. By using the combination of a transversely dispersed electron beam and a wave-front tilted seed laser, three-dimensional manipulation of the electron beam phase space can be utilized to significantly enhance the micro-bunching of seeded free-electron laser schemes, which will improve the performance and extend the short-wavelength range of a single-stage seeded free-electron laser. Theoretical analysis and numerical simulations demonstrate the capability of the proposed technique in a soft x-ray free-electron laser.

Feng, Chao; Deng, Haixiao; Zhao, Zhentang

2014-01-01T23:59:59.000Z

211

E-Print Network 3.0 - area electron beam Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

D.L. Summary: , Ann Arbor, MI 48109, USA Abstract We have used electron and photon beams from the 50 MV electron... the magnetic confinement of HE electron and photon...

212

A Plasma-Cathode Electron Source for Ribbon-Beam Generation at Forevacuum Pressures  

Science Journals Connector (OSTI)

A plasma electron source producing a ribbon beam at pressures of ... cathode is used as a plasma generator. Electrons are extracted through the emission slit in ... covered by a metal mesh. The maximum electron-b...

V. A. Burdovitsin; Yu. A. Burachevskii…

2003-03-01T23:59:59.000Z

213

Title of Document: EXPERIMENTAL STUDY OF SOLITONS ON INTENSE ELECTRON BEAMS  

E-Print Network (OSTI)

ABSTRACT Title of Document: EXPERIMENTAL STUDY OF SOLITONS ON INTENSE ELECTRON BEAMS Yichao Mo such as condensed matter physics, plasma physics, beam physics, optics, biology and medicine. Whereas solitons in electron beams have been predicted on theoretical grounds decades ago, they have been observed

Anlage, Steven

214

Submillimeter-resolution radiography of shielded structures with laser-accelerated electron beams  

E-Print Network (OSTI)

Submillimeter-resolution radiography of shielded structures with laser-accelerated electron beams (Received 24 March 2010; published 14 October 2010) We investigate the use of energetic electron beams beam (with energy >100 MeV) was generated by the process of laser-wakefield acceleration through

Umstadter, Donald

215

Inverse problems in elliptic charged-particle beams  

E-Print Network (OSTI)

The advantages of elliptic (or sheet) beams have been known for many years, but their inherent three-dimensional nature presents significant theoretical, design, and experimental challenges in the development of elliptic ...

Bhatt, Ronak Jayant

2006-01-01T23:59:59.000Z

216

Structured x-ray beams from twisted electrons by inverse Compton scattering of laser light  

E-Print Network (OSTI)

The inverse Compton scattering of laser light on high-energetic twisted electrons is investigated with the aim to construct spatially structured x-ray beams. In particular, we analyze how the properties of the twisted electrons, such as the topological charge and aperture angle of the electron Bessel beam, affects the energy and angular distribution of scattered x-rays. We show that with suitably chosen initial twisted electron states one can synthesize tailor-made x-ray beam profiles with a well-defined spatial structure, in a way not possible with ordinary plane-wave electron beams.

Seipt, D; Fritzsche, S

2014-01-01T23:59:59.000Z

217

THE POSSIBILITY OF GENERATION OF HIGH-ENERGY ELECTRON BEAM AT THE SNS FACILITY  

SciTech Connect

The linac of the SNS accelerator facility can be used to produce an electron beam with 300-400 MeV energy and relatively high current. At present, a few predesigned experiments with electron beam can be alternatively carried out at the SNS. However, the SNS linac is designed and optimized for acceleration of the H- beam, which creates problems when direct acceleration of electrons is considered. An alternative machine setup for electron acceleration and transport is discussed. Here, we present a study of the optimal electron beam parameters that can be achieved without any significant hardware changes in the SNS accelerator.

Gorlov, Timofey V [ORNL] [ORNL; Aleksandrov, Alexander V [ORNL] [ORNL; Danilov, Viatcheslav V [ORNL] [ORNL

2013-01-01T23:59:59.000Z

218

Characterization of Defocused Electron Beams and Welds in Stainless Steel and Refractory Metals using the Enhanced Modified Faraday Cup Diagnostic  

SciTech Connect

As the first part of a project to compare new generation, continuous wave, laser welding technology to traditional electron beam welding technology, electron beam welds were made on commercially pure vanadium refractory metal and 21-6-9 austenitic stainless steel. The electron beam welds were made while employing EB diagnostics to fully characterize the beams so that direct comparisons could be made between electron beam and laser beams and the welds that each process produces.

Elmer, J W

2009-01-23T23:59:59.000Z

219

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

DOE Patents (OSTI)

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.

Neil, G.R.

1996-07-30T23:59:59.000Z

220

Normal Conducting CW RF Gun Design for High Performance Electron Beams  

SciTech Connect

High repetition rate (>1 MHz), high charge (1 nC), low emittance (1 micron) electron beams are an important enabling technology for next generation light sources. Advanced Energy Systems has begun the development of an advanced, continuous-wave, normal-conducting radio frequency electron gun. This gun is designed to minimize thermal stress, allowing fabrication in copper, while providing low emittance electron beams. Beam dynamics performance will be presented along with thermal and stress analysis of the gun cavity design.

Bluem, Hans; Schultheiss, Tom; Young, L.M.; Rimmer, Robert

2008-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


221

Magnetic-field generation and electron-collimation analysis for propagating fast electron beams in overdense plasmas  

SciTech Connect

An analytical fluid model is proposed for artificially collimating fast electron beams produced in the interaction of ultraintense laser pulses with specially engineered low-density-core-high-density-cladding structure targets. Since this theory clearly predicts the characteristics of the spontaneously generated magnetic field and its dependence on the plasma parameters of the targets transporting fast electrons, it is of substantial relevance to the target design for fast ignition. The theory also reveals that the rapid changing of the flow velocity of the background electrons in a transverse direction (perpendicular to the flow velocity) caused by the density jump dominates the generation of a spontaneous interface magnetic field for these kinds of targets. It is found that the spontaneously generated magnetic field reaches as high as 100 MG, which is large enough to collimate fast electron transport in overdense plasmas. This theory is also supported by numerical simulations performed using a two-dimensional particle-in-cell code. It is found that the simulation results agree well with the theoretical analysis.

Cai Hongbo [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Zhu Shaoping; Chen Mo; Wu Sizhong [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); He, X. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Mima, Kunioki [Institute of Laser Engineering, Osaka University, 2-6 Yamadaoka, Suita, Osaka 565-0871 (Japan); Graduate School for the Creation of New Photonics Industries, 1955-1 Kurematsu, Nishiku, Hamamatsu, Sizuoka 431-1202 (Japan)

2011-03-15T23:59:59.000Z

222

Generation of high-quality mega-electron volt proton beams with intense-laser-driven nanotube accelerator  

SciTech Connect

An ion acceleration scheme using carbon nanotubes (CNTs) is proposed, in which embedded fragments of low-Z materials are irradiated by an ultrashort intense laser to eject substantial numbers of electrons. Due to the resultant characteristic electrostatic field, the nanotube and embedded materials play the roles of the barrel and bullets of a gun, respectively, to produce highly collimated and quasimonoenergetic ion beams. Three-dimensional particle simulations, that take all the two-body Coulomb interactions into account, demonstrate generation of quasimonoenergetic MeV-order proton beams using nanometer-size CNT under a super-intense electrostatic field {approx}10{sup 14} V m{sup -1}.

Murakami, M. [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan)] [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan); Tanaka, M. [Department of Engineering, Chubu University, Aichi 487-8501 (Japan)] [Department of Engineering, Chubu University, Aichi 487-8501 (Japan)

2013-04-22T23:59:59.000Z

223

Fluorescence from CsF ionic excimers excited by an electron beam  

SciTech Connect

Mixtures of rare gases and cesium fluoride vapors were excited by an intense relativistic electron beam. The fluorescence of the Cs[sup 2+]F[sup [minus

XYang, T.T.; Gylys, V.T.; Bower, R.D.; Harris, D.G. (Rocketdyne Division, Rockwell International, 6633 Canoga Avenue, Canoga Park, California 91303 (United States))

1992-08-01T23:59:59.000Z

224

Prospects for advanced electron cyclotron resonance and electron beam ion source charge breeding methods for EURISOL  

SciTech Connect

As the most ambitious concept of isotope separation on line (ISOL) facility, EURISOL aims at producing unprecedented intensities of post-accelerated radioactive isotopes. Charge breeding, which transforms the charge state of radioactive beams from 1+ to an n+ charge state prior to post-acceleration, is a key technology which has to overcome the following challenges: high charge states for high energies, efficiency, rapidity and purity. On the roadmap to EURISOL, a dedicated R and D is being undertaken to push forward the frontiers of the present state-of-the-art techniques which use either electron cyclotron resonance or electron beam ion sources. We describe here the guidelines of this R and D.

Delahaye, P.; Jardin, P.; Maunoury, L.; Traykov, E.; Varenne, F. [GANIL, CEA/DSM-CNRS/IN2P3, Bd. Becquerel, BP 55027, 14076 Caen Cedex 05 (France); Galata, A.; Porcellato, A. M.; Prete, G. F. [INFN-Laboratori Nazionali di Legnaro, Viale dell'Universita 2, 35020 Legnaro, Padova (Italy); Angot, J.; Lamy, T.; Sortais, P.; Thuillier, T. [LPSC Grenoble, 53, rue des Martyrs, 38026 Grenoble Cedex (France); Ban, G. [LPC Caen, 6 bd Marechal Juin, 14050 Caen Cedex (France); Celona, L.; Lunney, D. [INFN-Laboratori Nazionali del Sud, via S.Sofia 62, 95125 Catania (Italy); Choinski, J.; Gmaj, P.; Jakubowski, A.; Steckiewicz, O. [Heavy Ion Laboratory, University of Warsaw, ul. Pasteura 5a, 02 093 Warsaw (Poland); Kalvas, T. [Department of Physics, University of Jyvaeskylae, PB 35 (YFL) 40351 Jyvaeskylae (Finland); and others

2012-02-15T23:59:59.000Z

225

Space Charge Correction on Emittance Measurement of Low Energy Electron Beams  

SciTech Connect

The goal of any particle accelerator is to optimize the transport of a charged particle beam along a set path by confining the beam to a small region close to the design trajectory and directing it accurately along the beamline. To do so in the simplest fashion, accelerators use a system of magnets that exert approximately linear electromagnetic forces on the charged beam. These electromagnets bend the beam along the desired path, in the case of bending magnets, and constrain the beam to the desired area through alternating focusing and defocusing effects, in the case of quadrupole magnets. We can model the transport of such a beam through transfer matrices representing the actions of the various beamline elements. However, space charge effects, produced from self electric fields within the beam, defocus the beam and must be accounted for in the calculation of beam emittance. We present below the preliminary results of a MATLAB code built to model the transport of a charged particle beam through an accelerator and measure the emittance under the influence of space charge effects. We demonstrate the method of correctly calculating the emittance of a beam under space charge effects using a least square fit to determine the initial properties of the beam given the beam size measured at a specific point after transport.

Treado, Colleen J.; /Massachusetts U., Amherst

2012-09-07T23:59:59.000Z

226

Stability properties of free-electron laser in Raman regime with thermal electron beam  

SciTech Connect

In the context of kinetic theory an expression for the growth rate of a free-electron laser, under the weak resonance instability condition, for full dispersion relation has been obtained. The space-charge potential is included in the analysis and the expression for growth rate reduces to that of the Compton regime under the low density condition. With the assumption of a spread in the longitudinal momentum in the form of a Gaussian distribution function, the effect of the thermal electron beam on the growth rate is studied. The results are compared to another linear theory, a computer simulation, and an experiment.

Chakhmachi, A. [Plasma Physics and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, Atomic Energy Organization of Iran, P.O. Box 14155-1339, Tehran (Iran, Islamic Republic of); Department of Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of); Maraghechi, B. [Department of Physics, Amirkabir University of Technology, P.O. Box 15875-4413, Tehran (Iran, Islamic Republic of)

2009-04-15T23:59:59.000Z

227

Longitudinal bunch profile and electron beam energy spread  

NLE Websites -- All DOE Office Websites (Extended Search)

Magnets and Power Supplies Up: APS Storage Ring Parameters Previous: Magnets and Power Supplies Up: APS Storage Ring Parameters Previous: Storage Ring Operation Modes Longitudinal bunch profile and electron beam energy spread Longitudinal bunch profile depends mainly on the single bunch charge (or single bunch current). Every APS operating mode has different single bunch current and therefore has different bunch length. The plot below shows measured bunch length dependence on the single bunch current between 1 mA and 18 mA and the fit that uses the formula shown below the plot. The bunch length in this plot is shorter than it was quoted before. Earlier numbers were obtained using a Gaussian fit, present numbers are calculated as true standard deviation. \includegraphics[width=0.8\textwidth]{otherFiles/bunchLength.eps} The following formula obtained by fitting the log of the data above can be

228

An Optimized Nanoparticle Separator Enabled by Electron Beam Induced Deposition  

SciTech Connect

Size based separations technologies will inevitably benefit from advances in nanotechnology. Direct write nanofabrication provides a useful mechanism to deposit/etch nanoscale elements in environments otherwise inaccessible to conventional nanofabrication techniques. Here, electron beam induced deposition (EBID) was used to deposit an array of nanoscale features in a 3D environment with minimal material proximity effects outside the beam interaction region (BIR). Specifically, the membrane component of a nanoparticle separator was fabricated by depositing a linear array of sharply tipped nanopillars, with a singular pitch, designed for sub 50nm nanoparticle permeability. The nanopillar membrane was used in a dual capacity to control the flow of nanoparticles in the transaxial direction of the array while facilitating the sealing of the cellular sized compartment in the paraxial direction. An optimized growth recipe resulted which (1) maximized the growth efficiency of the membrane (which minimizes proximity effects), (2) preserved the fidelity of spacing between nanopillars (which maximizes the size based gating quality of the membrane) while (3) maintaining sharp nanopillar apexes for impaling an optically transparent polymeric lid critical for device sealing.

Fowlkes, Jason Davidson [ORNL; Doktycz, Mitchel John [ORNL; Rack, P. D. [University of Tennessee, Knoxville (UTK)

2010-01-01T23:59:59.000Z

229

Nano electron source fabricated by beam-induced deposition and its unique feature  

Science Journals Connector (OSTI)

Abstract The fabrication of nanoscale field emitters with gate structures using beam-induced deposition and their field emission properties are described. Nano electron sources can be fabricated by electron-beam-induced deposition without additional processes. The inherent issues of process contamination and the effectiveness of post cleaning using annealing or radical oxygen gas exposure to remove contaminants introduced during beam deposition are also discussed. In addition, coherent electron beams for electron wave interference emitted from a beam-deposited Pt field emitter were investigated by field emission microscopy and field ion microscopy. The interference fringe patterns observed for beam-deposited Pt field emitters were attributed to electron wave interference occurring at two adjacent emission sites on a single Pt nanocrystal.

Katsuhisa Murakami; Mikio Takai

2015-01-01T23:59:59.000Z

230

Helium, Iron and Electron Particle Transport and Energy Transport Studies on the TFTR Tokamak  

DOE R&D Accomplishments (OSTI)

Results from helium, iron, and electron transport on TFTR in L-mode and Supershot deuterium plasmas with the same toroidal field, plasma current, and neutral beam heating power are presented. They are compared to results from thermal transport analysis based on power balance. Particle diffusivities and thermal conductivities are radially hollow and larger than neoclassical values, except possibly near the magnetic axis. The ion channel dominates over the electron channel in both particle and thermal diffusion. A peaked helium profile, supported by inward convection that is stronger than predicted by neoclassical theory, is measured in the Supershot The helium profile shape is consistent with predictions from quasilinear electrostatic drift-wave theory. While the perturbative particle diffusion coefficients of all three species are similar in the Supershot, differences are found in the L-Mode. Quasilinear theory calculations of the ratios of impurity diffusivities are in good accord with measurements. Theory estimates indicate that the ion heat flux should be larger than the electron heat flux, consistent with power balance analysis. However, theoretical values of the ratio of the ion to electron heat flux can be more than a factor of three larger than experimental values. A correlation between helium diffusion and ion thermal transport is observed and has favorable implications for sustained ignition of a tokamak fusion reactor.

Synakowski, E. J.; Efthimion, P. C.; Rewoldt, G.; Stratton, B. C.; Tang, W. M.; Grek, B.; Hill, K. W.; Hulse, R. A.; Johnson, D .W.; Mansfield, D. K.; McCune, D.; Mikkelsen, D. R.; Park, H. K.; Ramsey, A. T.; Redi, M. H.; Scott, S. D.; Taylor, G.; Timberlake, J.; Zarnstorff, M. C. (Princeton Univ., NJ (United States). Plasma Physics Lab.); Kissick, M. W. (Wisconsin Univ., Madison, WI (United States))

1993-03-00T23:59:59.000Z

231

Averaged dynamics of ultra-relativisitc charged particles beams  

E-Print Network (OSTI)

In this thesis, we consider the suitability of using the charged cold fluid model in the description of ultra-relativistic beams. The method that we have used is the following. Firstly, the necessary notions of kinetic theory and differential geometry of second order differential equations are explained. Then an averaging procedure is applied to a connection associated with the Lorentz force equation. The result of this averaging is an affine connection on the space-time manifold. The corresponding geodesic equation defines the averaged Lorentz force equation. We prove that for ultra-relativistic beams described by narrow distribution functions, the solutions of both equations are similar. This fact justifies the replacement of the Lorentz force equation by the simpler {\\it averaged Lorentz force equation}. After this, for each of these models we associate the corresponding kinetic model, which are based on the Vlasov equation and {\\it averaged Vlasov equation} respectively. The averaged Vlasov equation is simpler than the original Vlasov equation. This fact allows us to prove that the differential operation defining the averaged charged cold fluid equation is controlled by the {\\it diameter of the distribution function}, by powers of the {\\it energy of the beam} and by the time of evolution $t$. We show that the Vlasov equation and the averaged Vlasov equation have similar solutions, when the initial conditions are the same. Finally, as an application of the {\\it averaged Lorentz force equation} we re-derive the beam dynamics formalism used in accelerator physics from the Jacobi equation of the averaged Lorentz force equation.

Ricardo Gallego Torromé

2012-06-19T23:59:59.000Z

232

A PLASMA CHANNEL BEAM CONDITIONER FOR A FREE ELECTRON LASER  

E-Print Network (OSTI)

plasma focusing and plasma accel- eration, but further beam compression is not required. The resulting

Wurtele, Jonathan

233

Initial optical-transition radiation measurements of the electron beam for the Boeing free-electron-laser experiment  

Science Journals Connector (OSTI)

The potential for characterization of electron beams at ? 100 MeV at the Boeing Free Electron Laser (FEL) facility by optical-transition radiation (OTR) techniques has been demonstrated as an important complement to other diagnostic means. Electron beam properties such as spatial profile and position, current intensity, emittance and energy were studied using OTR. Initial examples including transport through the 5 m wiggler and the resolution of Cherenkov radiation and spontaneous-emission radiation competitive sources are discussed.

A.H. Lumpkin; R.B. Fiorito; D.W. Rule; D.H. Dowell; W.C. Sellyey; A.R. Lowrey

1990-01-01T23:59:59.000Z

234

Polarized-Beams Studies of Spin Exchange in Electron-Hydrogen Collisions  

Science Journals Connector (OSTI)

The application of polarized beams to the study of interference phenomena in electron-hydrogen collisions is reviewed. In particular, the results of the first experiment using polarized electrons to study the ...

M. S. Lubell

1980-01-01T23:59:59.000Z

235

E-Print Network 3.0 - axisymmetric electron beam Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

. Factors controlling the plasma electron temperature when heated by 18-20keV neutral beams with a power... from periphery, electron temperatures of 150-160eV were obtained with...

236

Study on electron beam emission from a low energy plasma focus device  

Science Journals Connector (OSTI)

Electron beam emission from a 2.2 kJ plasma focus device has been studied by using a charge collector. Multiple bunches of electron beams having short live are observed. The electron beam current is found to be strongly dependent on the operating pressure and the average electron beam current at 0.3 Torr of nitrogen (optimum pressure) is found to be around 13.5 kA. The highest value of electron beam charge and density are estimated at the optimum operating pressure and found to be around 7.5 mC and 4.5 × 10 16  m ?3 , respectively. The electron energy distribution spreads from approximately 10 keV to more than 200 keV with a most probable distribution within 80 to 110 keV. The results are discussed in this Letter.

N.K. Neog; S.R. Mohanty

2007-01-01T23:59:59.000Z

237

An electron beam polarimeter based on scattering from a windowless, polarized hydrogen gas target  

SciTech Connect

Here we present the idea to develop a precision polarimeter for low energy, intense polarized electron beams using a windowless polarized hydrogen gas cell fed by an atomic beam source. This technique would use proven technology used successfully in both the electron scattering experiments: HERMES with 27 GeV electron and positron beams at DESY, and BLAST with 850 MeV electron beams at MIT-Bates. At 100 MeV beam energy, both spin-dependent Mo/ller and elastic electron-proton scattering processes have a high cross section and sizable spin asymmetries. The concept is described and estimates for realistic rates for elastic electron-proton scattering and Mo/ller scattering are presented. A number of important issues which affect the ultimate systematic uncertainty are identified.

Bernauer, Jan; Milner, Richard [Laboratory for Nuclear Science, MIT, Cambridge, MA, 02139 (United States)

2013-11-07T23:59:59.000Z

238

Matching extended-SSD electron beams to multileaf collimated photon beams in the treatment of head and neck cancer  

SciTech Connect

Purpose: Matching the penumbra of a 6 MeV electron beam to the penumbra of a 6 MV photon beam is a dose optimization challenge, especially when the electron beam is applied from an extended source-to-surface distance (SSD), as in the case of some head and neck treatments. Traditionally low melting point alloy blocks have been used to define the photon beam shielding over the spinal cord region. However, these are inherently time consuming to construct and employ in the clinical situation. Multileaf collimators (MLCs) provide a fast and reproducible shielding option but generate geometrically nonconformal approximations to the desired beam edge definition. The effects of substituting Cerrobend for the MLC shielding mode in the context of beam matching with extended-SSD electron beams are the subject of this investigation. Methods: Relative dose beam data from a Varian EX 2100 linear accelerator were acquired in a water tank under the 6 MeV electron beam at both standard and extended-SSD and under the 6 MV photon beam defined by Cerrobend and a number of MLC stepping regimes. The effect of increasing the electron beam SSD on the beam penumbra was assessed. MLC stepping was also assessed in terms of the effects on both the mean photon beam penumbra and the intraleaf dose-profile nonuniformity relative to the MLC midleaf. Computational techniques were used to combine the beam data so as to simulate composite relative dosimetry in the water tank, allowing fine control of beam abutment gap variation. Idealized volumetric dosimetry was generated based on the percentage depth-dose data for the beam modes and the abutment geometries involved. Comparison was made between each composite dosimetry dataset and the relevant ideal dosimetry dataset by way of subtraction. Results: Weighted dose-difference volume histograms (DDVHs) were produced, and these, in turn, summed to provide an overall dosimetry score for each abutment and shielding type/angle combination. Increasing the electron beam SSD increased the penumbra width (defined as the lateral distance of the 80% and 20% isodose contours) by 8-10 mm at the depths of 10-20 mm. Mean photon beam penumbra width increased with increased MLC stepping, and the mean MLC penumbra was {approx_equal}1.5 times greater than that across the corresponding Cerrobend shielding. Intraleaf dose discrepancy in the direction orthogonal to the beam edge also increased with MLC stepping. Conclusions: The weighted DDVH comparison techniques allowed the composite dosimetry resulting from the interplay of the abovementioned variables to be ranked. The MLC dosimetry ranked as good or better than that resulting from beam matching with Cerrobend for all except large field overlaps (-2.5 mm gap). The results for the linear-weighted DDVH comparison suggest that optimal MLC abutment dosimetry results from an optical surface gap of around 1{+-}0.5 mm. Furthermore, this appears reasonably lenient to abutment gap variation, such as that arising from uncertainty in beam markup or other setup errors.

Steel, Jared; Stewart, Allan; Satory, Philip [Auckland Regional Blood and Cancer Service, Auckland City Hospital, 2 Park Road, Grafton, Auckland 1023 (New Zealand)

2009-09-15T23:59:59.000Z

239

CP-violation reach of an electron capture neutrino beam  

E-Print Network (OSTI)

This article extends the work of Bernabeu and Espinoza by examining the CP-violation reach of a $^{150}$Dy electron capture beam through the variation of the two Lorentz boosts, the number of useful electron capture decays, the relative run time of each boost and the number of atmospheric backgrounds. The neutrinos are assumed to be sourced at CERN with an upgraded SPS and are directed towards a 440 kton Water Cerenkov detector located at the Canfranc laboratory. Two large `CP-coverage' choices for the boost pairings are found; a $\\delta$-symmetrical coverage for $(\\gamma_{1}, \\gamma_{2})$ = (280, 160) and an $\\delta$-asymmetric coverage for $(\\gamma_{1}, \\gamma_{2})$ = (440,150). With a nominal useful decay rate of $N_{\\rm ions} = 10^{18}$ ions per year, the $\\delta$-symmetric setup can rule out CP-conservation down to $\\sin^{2}2\\theta_{13} = 3\\cdot 10^{-4}$. To reach $\\sin^{2}2\\theta_{13} = 1\\cdot 10^{-3}$ for both $\\delta 0$ requires a useful decay rate of $N_{\\rm ions} = 6\\cdot 10^{17}$ ions per year.

Christopher Orme

2010-07-12T23:59:59.000Z

240

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, for the first time, positron beams. We also discuss measure­ ments on plasma lens­induced synchrotron radiation and laser­ and beam­plasma interactions. 1 INTRODUCTION The plasma lens was proposed as a final focusing

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241

In-situ determination of energy species yields of intense particle beams  

DOE Patents (OSTI)

Objects of the present invention are provided for a particle beam having a full energy component at least as great as 25 keV, which is directed onto a beamstop target, such that Rutherford backscattering, preferably near-surface backscattering occurs. The geometry, material composition and impurity concentration of the beam stop are predetermined, using any suitable conventional technique. The energy-yield characteristic response of backscattered particles is measured over a range of angles using a fast ion electrostatic analyzer having a microchannel plate array at its focal plane. The knee of the resulting yield curve, on a plot of yield versus energy, is analyzed to determine the energy species components of various beam particles having the same mass.

Kugel, H.W.; Kaita, R.

1983-09-26T23:59:59.000Z

242

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

SciTech Connect

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.

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

243

Simulation and optimization of a 10 A electron gun with electrostatic compression for the electron beam ion source  

SciTech Connect

Increasing the current density of the electron beam in the ion trap of the Electron Beam Ion Source (EBIS) in BNL's Relativistic Heavy Ion Collider facility would confer several essential benefits. They include increasing the ions' charge states, and therefore, the ions' energy out of the Booster for NASA applications, reducing the influx of residual ions in the ion trap, lowering the average power load on the electron collector, and possibly also reducing the emittance of the extracted ion beam. Here, we discuss our findings from a computer simulation of an electron gun with electrostatic compression for electron current up to 10 A that can deliver a high-current-density electron beam for EBIS. The magnetic field in the cathode-anode gap is formed with a magnetic shield surrounding the gun electrodes and the residual magnetic field on the cathode is (5 Division-Sign 6) Gs. It was demonstrated that for optimized gun geometry within the electron beam current range of (0.5 Division-Sign 10) A the amplitude of radial beam oscillations can be maintained close to 4% of the beam radius by adjusting the injection magnetic field generated by a separate magnetic coil. Simulating the performance of the gun by varying geometrical parameters indicated that the original gun model is close to optimum and the requirements to the precision of positioning the gun elements can be easily met with conventional technology.

Pikin, A.; Beebe, E. N.; Raparia, D. [Brookhaven National Laboratory, Upton, New York 11973 (United States)

2013-03-15T23:59:59.000Z

244

Electron Climbing a 'Devil's Staircase' in Wave-Particle Interaction  

SciTech Connect

Numerous nonlinear driven systems display spectacular responses to forcing, including chaos and complex phase-locking plateaus characterized by 'devil's staircase', Arnold tongues, and Farey trees. In the universality class of Hamiltonian systems, a paradigm is the motion of a charged particle in two waves, which inspired a renormalization group method for its description. Here we report the observation of the underlying 'devil's staircase' by recording the beam velocity distribution function at the outlet of a traveling wave tube versus the amplitude of two externally induced waves.

Macor, Alessandro; Doveil, Fabrice; Elskens, Yves [Physique des interactions ioniques et moleculaires, Unite 6633 CNRS-Universite de Provence, Equipe turbulence plasma, case 321, Centre de Saint-Jerome, F-13397 Marseille cedex 20 (France)

2005-12-31T23:59:59.000Z

245

Spectral evolution in an electron beam pumped XeF laser  

SciTech Connect

A spectral sweep in the 353-nm band of an electron beam pumped XeF laser has been investigated. The time-integrated lasing spectra broaden as the pulse length, electron beam pump rate, and intracavity flux are increased. Several possible explanations are discussed.

Harris, D.G.; Burde, D.H.; Malins, R.J.; Tillotson, J.H.

1987-10-19T23:59:59.000Z

246

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

247

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

E-Print Network (OSTI)

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

Umstadter, Donald

248

S&TR | March/April 2008: Standardizing the Art of Electron-Beam Welding  

NLE Websites -- All DOE Office Websites (Extended Search)

Standardizing the Art of Electron-Beam Welding. Standardizing the Art of Electron-Beam Welding. WELDED materials are an integral part of everyday life. Appliances, cars, and bridges are all made by welding materials together. But not all welds are created equal. Welding methods vary in complexity, time, and cost, depending on a product's requirements and purpose. In electron-beam (EBeam) welding, an electron beam generated in a vacuum creates a fusing heat source that can unite almost any metals. This method produces deep welds without adding excessive heat that can adversely affect the properties of the surrounding metal. In the nuclear energy and aerospace industries, electron-beam welding is preferred for manufacturing high-value welds-those in which defects cannot be tolerated. The Department of Energy's (DOE's) nuclear weapons

249

SMALL PARTICLES-ELECTRONIC PROPERTIES /I. SMALL METAL PARTICLES : COMPLEMENTARY ASPECTS OF THE N.M.R.  

E-Print Network (OSTI)

, de l'interaction hyperfine electron-noyau et donc du facteur spin depairing. La largeur de la raie RSMALL PARTICLES-ELECTRONIC PROPERTIES /I. SMALL METAL PARTICLES : COMPLEMENTARY ASPECTS OF THE N paires dans l'etat fondamental et la largeur de la raie de resonance des electrons de conduction lorsque

Boyer, Edmond

250

PHYSICS WITH AND PHYSICS OF COLLIDING ELECTRON BEAMS  

E-Print Network (OSTI)

contributed so much to the physics of colliding beams, theyto reap so little from the physics with colliding beams.Conference on High-Energy Physics, Vienna" September 1968 (

Pellegrini, Claudio

2008-01-01T23:59:59.000Z

251

Nanostructure fabrication by electron and ion beam patterning of nanoparticles  

E-Print Network (OSTI)

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, ...

Kong, David Sun, 1979-

2004-01-01T23:59:59.000Z

252

Plasma Panel Sensors for Particle and Beam Detection  

E-Print Network (OSTI)

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.

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

253

Studies of Emittance Growth and Halo Particle Production in Intense Charged Particle Beams  

E-Print Network (OSTI)

-gradient transport systems. · Applications: Accelerator systems for high energy and nuclear physics applications and Phase Advance Characterize the Motion ­ Emittance is a Measure of Beam Quality Here, the vacuum phase

Gilson, Erik

254

Quantitative experiments with electrons in a positively charged Beam  

E-Print Network (OSTI)

analyzer, and the gas electron source diagnostic (GESD) tocommissioned the Gas-Electron Source Diagnostic (GESD) tosources. Each type of electron source can therefor affect an

2006-01-01T23:59:59.000Z

255

Electron Cloud in Steel Beam Pipe vs Titanium Nitride Coated and Amorphous Carbon Coated Beam Pipes in Fermilab's Main Injector  

SciTech Connect

This paper documents the use of four retarding field analyzers (RFAs) to measure electron cloud signals created in Fermilab’s Main Injector during 120 GeV operations. The first data set was taken from September 11, 2009 to July 4, 2010. This data set is used to compare two different types of beam pipe that were installed in the accelerator. Two RFAs were installed in a normal steel beam pipe like the rest of the Main Injector while another two were installed in a one meter section of beam pipe that was coated on the inside with titanium nitride (TiN). A second data run started on August 23, 2010 and ended on January 10, 2011 when Main Injector beam intensities were reduced thus eliminating the electron cloud. This second run uses the same RFA setup but the TiN coated beam pipe was replaced by a one meter section coated with amorphous carbon (aC). This section of beam pipe was provided by CERN in an effort to better understand how an aC coating will perform over time in an accelerator. The research consists of three basic parts: (a) continuously monitoring the conditioning of the three different types of beam pipe over both time and absorbed electrons (b) measurement of the characteristics of the surrounding magnetic fields in the Main Injector in order to better relate actual data observed in the Main Injector with that of simulations (c) measurement of the energy spectrum of the electron cloud signals using retarding field analyzers in all three types of beam pipe.

Backfish, Michael

2013-04-01T23:59:59.000Z

256

Space-charged-induced emittance growth in the transport of high-brightness electron beams  

SciTech Connect

The emittance induced by space charge in a drifting beam of finite length has been investigated, and a scaling law has been obtained from simple considerations of the different rates of expansion of different portions of the beam. The scaling law predicts the initial rate of emittance growth, before the beam shape has distorted significantly, and thus represents an upper bound on the rate of emittance increase. This scaling law has been substantiated by particle-in-cell simulation and the dependence on geometric factors evaluated for specific choices of the beam profile. For long, axially nonuniform beams, the geometric factors have been evaluated explicitly for Gaussian profiles, and other shapes.

Jones, M.E.; Carlsten, B.E.

1987-03-01T23:59:59.000Z

257

Electron Beam Charge Diagnostics for Laser Plasma Accelerators  

E-Print Network (OSTI)

the 1989 Particle Accelerator Conference (IEEE, Piscataway,the 1993 Particle Accelerator Conference (IEEE, Piscataway,Diagnostics for Laser Plasma Accelerators K. Nakamura, 1 A.

Nakamura, Kei

2012-01-01T23:59:59.000Z

258

Microwave beam steerers for electronically scanned reflectometers (abstract)  

SciTech Connect

One of the problems encountered in the application of reflectometry to fusion plasmas is that the transmit antenna must be aligned such that the reflected wave form is successfully collected by a suitably arranged receive antenna. This task is made even more difficult in the case of shaped plasmas, or when plasma motion is such that the incident wave is no longer normal to the plasma surface. One would ideally like to have antennas which may be steered in real time to compensate for changes in plasma shape and/or position. A program has been initiated at U.C. Davis to address this problem, and microwave beam steerers suitable for electronically scanned reflectometers have been developed. The approach taken has been to develop phased antenna array (PAA) concepts which operate over broad bandwidths. Laboratory test results of a proof-of-principle PAA system will be presented, along with a description of ongoing research activities by U.C. Davis in this field. {copyright} {ital 1999 American Institute of Physics.}

Hsia, R.P.; Zhang, W.; Jiang, F.; Domier, C.W.; Luhmann, N.C. Jr. [University of California, Davis, Davis, California 95616 (United States)] [University of California, Davis, Davis, California 95616 (United States)

1999-01-01T23:59:59.000Z

259

Development of ion injection into the BNL test electron beam ion source using a prototype low energy beam transfer switchyard and a hollow  

E-Print Network (OSTI)

Development of ion injection into the BNL test electron beam ion source using a prototype low-to-pulse basis, the BNL RHIC electron beam ion source EBIS will use injection of primary "seed" ions from energy beam transfer switchyard and a hollow cathode ion source ,,abstract...a...,b... E. N. Beebe, J. G

260

Positron acceleration by plasma wake fields driven by a hollow electron beam  

E-Print Network (OSTI)

A scheme of wake field generation for positron acceleration using hollow or donut shaped electron driver beams is studied. An annular shaped, electron free region forms around a hollow driver beam creating a favorable region (longitudinal field is accelerating and transverse field is focusing and radially linear) for positron acceleration. Accelerating gradients of the order of 10 GV/m are produced by a hollow electron beam driver with FACET like parameters. The peak accelerating field increases linearly with the total charge in the beam driver while the axial size of the favorable region ($\\sim$ one plasma wavelength) remains approximately fixed. The radial size drops with the total charge but remains large enough for the placement of a witness positron beam. We simulate an efficient acceleration of a 23 GeV positron beam to 35.4 GeV with a maximum energy spread of 0.4\\% and very small emittance over a plasma length of 140 cm.

Jain, Neeraj; Palastro, J P

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


261

Experimental optimization of the 6-dimentional electron beam emittance at the NSLS SDL  

SciTech Connect

Experimental optimization of the 6-dimensional electron beam emittance generated by a Magnesium (Mg) photocathode RF gun is presented in this report. A new electron beam optimization algorithm for a low charge (<100 pC) beam was experimentally demonstrated; where the electron beam velocity bunching inside the RF gun plays a critical role, and the transverse emittance as a function of the laser-RF timing jitter was experimentally characterized for the first time. A 20 pC electron beam was optimized to have a normalized slice emittance of 0.15 mm mrad and a longitudinal projected emittance of 3.9 ps keV. Furthermore, the upper limit of the measured thermal emittance - 0.5 mm mrad per mm of the rms laser size, is about 50% lower than the theoretical prediction for a Mg cathode (Qian et al., 2010) [1].

Qian, H.J.; Murphy, J.; Shen,Y.; Tang,C.X.; Wang,X.J.

2011-05-13T23:59:59.000Z

262

A comparison of weak-turbulence and PIC simulations of weak electron-beam plasma interaction  

E-Print Network (OSTI)

Quasilinear theory has long been used to treat the problem of a weak electron beam interacting with plasma and generating Langmuir waves. Its extension to weak-turbulence theory treats resonant interactions of these Langmuir waves with other plasma wave modes, in particular ion-sound waves. These are strongly damped in plasma of equal ion and electron temperatures, as sometimes seen in, for example, the solar corona and wind. Weak turbulence theory is derived in the weak damping limit, with a term describing ion-sound wave damping then added. In this paper we use the EPOCH particle-in-cell code to numerically test weak turbulence theory for a range of electron-ion temperature ratios. We find that in the cold ion limit the results agree well, but increasing ion temperature the three-wave resonance becomes broadened in proportion to the ion-sound wave damping rate. This may be important in, for example, the theory of solar radio bursts, where the spectrum of Langmuir waves is critical. Additionally we establish...

Ratcliffe, Heather; Rozenan, Mohammed B Che; Nakariakov, Valery

2014-01-01T23:59:59.000Z

263

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

SciTech Connect

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.

Hershcovitch,A.

2009-03-01T23:59:59.000Z

264

Electron Source in Photoinduced Hydrogen Production on Pt-Supported TiO2 Particles  

Science Journals Connector (OSTI)

Electron Source in Photoinduced Hydrogen Production on Pt-Supported TiO2 Particles ... Comment on “Electron Source in Photoinduced Hydrogen Production on Pt-Supported TiO2 Particles” ... Comment on “Electron Source in Photoinduced Hydrogen Production on Pt-Supported TiO2 Particles” ...

Toshiyuki Abe; Eiji Suzuki; Kentaro Nagoshi; Kohichi Miyashita; Masao Kaneko:

2000-03-24T23:59:59.000Z

265

Slow positron annihilation spectroscopy and electron microscopy of electron beam evaporated cobalt and nickel silicides  

SciTech Connect

Metal silicide thin films on single-crystal silicon substrates are the subject of much research, due to their applications as electrical contacts and interconnects, diffusion barriers, low resistance gates, and field-assisted positron moderators, among others. Defects within the silicide layer and/or at the silicide/silicon interface are detrimental to device performance, since they can act as traps for charge carriers, as well as positrons. Pinholes penetrating the film are another detriment particularly for cobalt silicide films, since they allow electrons to permeate the film, rather than travel ballistically, in addition to greatly increasing surface area for recombination events. A series of epitaxial cobalt and nickel silicide thin films, deposited via electron-beam evaporation and annealed at various temperatures, have been grown on single-crystal silicon (111) substrates, in an effort to establish a relationship between deposition and processing parameters and film quality. The films have been analyzed by transmission and scanning electron microscopy, sputter depth profile Auger, and slow positron annihilation spectroscopy. The latter has been shown to both correlate and complement the traditional electron microscopy results.

Frost, R.L.; DeWald, A.B. (Georgia Institute of Technology, Atlanta, Georgia 30332 (USA)); Zaluzec, M.; Rigsbee, J.M. (University of Illinois, Urbana, Illinois 61801 (USA)); Nielsen, B.; Lynn, K.G. (Brookhaven National Laboratory, Upton, New York 11973 (USA))

1990-07-01T23:59:59.000Z

266

Formation and nonlinear dynamics of the squeezed state of a helical electron beam with additional deceleration  

SciTech Connect

Results of numerical simulations and analysis of the formation and nonlinear dynamics of the squeezed state of a helical electron beam in a vircator with a magnetron injection gun as an electron source and with additional electron deceleration are presented. The ranges of control parameters where the squeezed state can form in such a system are revealed, and specific features of the system dynamics are analyzed. It is shown that the formation of a squeezed state of a nonrelativistic helical electron beam in a system with electron deceleration is accompanied by low-frequency longitudinal dynamics of the space charge.

Egorov, E. N., E-mail: evgeniy.n.egorov@gmail.com; Koronovskii, A. A.; Kurkin, S. A.; Hramov, A. E. [Chernyshevsky Saratov State University (Russian Federation)] [Chernyshevsky Saratov State University (Russian Federation)

2013-11-15T23:59:59.000Z

267

Beam interaction measurements with a Retarding Field Analyzer in a high-current high-vacuum positively charged particle accelerator  

Science Journals Connector (OSTI)

A Retarding Field Analyzer (RFA) was inserted in a drift region of the magnetic transport section of the High-Current Experiment (HCX), that is at high-vacuum, to measure ions and electrons resulting from beam interaction with background gas and walls. The ions are expelled during the beam pulse by the space–charge potential and the electrons are expelled mainly at the end of the beam, when the beam potential decays. The ion energy distribution shows the beam potential of ? 2100 V and the beam–background gas total cross-section of 3.1 × 10 - 19 m 2 . The electron energy distribution reveals that the expelled electrons are mainly desorbed from the walls and gain ? 22 eV from the beam potential decaying with time before entering the RFA. Details of the RFA design and of the measured energy distributions are presented and discussed.

M. Kireeff Covo; A.W. Molvik; A. Friedman; J.J. Barnard; P.A. Seidl; B.G. Logan; D. Baca; J.L. Vujic

2007-01-01T23:59:59.000Z

268

Electrical properties of MIS capacitor using low temperature electron beam gun--evaporated HfAlO dielectrics  

E-Print Network (OSTI)

Electrical properties of MIS capacitor using low temperature electron beam gun--evaporated Hf of $1.45 nm was achieved in HfAlO films deposited by an electron beam gun evap- orator on unheated p of electron beam gun (EBG) evaporation to deposit high quality HfAlO films close to room temperature

Eisenstein, Gadi

269

Study of a liquid metal ion source for external ion injection into electron-beam ion source  

E-Print Network (OSTI)

Study of a liquid metal ion source for external ion injection into electron-beam ion source A into electron-beam ion source EBIS . It does not use a buffer gas and therefore it provides only a very small types of low-charged ion sources have been used for external ion injection into BNL electron-beam ion

270

Numerical Optimization of Electron Beams for High Brightness x- and {gamma}-Ray Production  

SciTech Connect

Production of high-brightness x- and {gamma}-ray beams using Compton-scattering schemes requires high-brightness electron beams; to minimize the output photon bandwidth, the electron beam emittance must also be minimized. This emittance minimization is in conflict with the desire to increase the electron bunch charge and maximize the number of scatterers at the interaction point. We study here, using a combination of PARMELA and well-benchmarked, Compton-scattering codes, the impact of laser temporal and spatial profiles on the emittance produced in a photoinjector, and the trade-off between charge and emittance in scattered photon brightness and flux.

Gibson, David J.; Anderson, Scott G.; Hartemann, Frederic V.; Siders, Craig W.; Tremaine, Aaron M.; Barty, Christopher P. J. [Lawrence Livermore National Laboratory, Livermore, CA 94550 (United States)

2006-11-27T23:59:59.000Z

271

Generation of electron beams from a laser-based advanced accelerator at Shanghai Jiao Tong University  

E-Print Network (OSTI)

At Shanghai Jiao Tong University, we have established a research laboratory for advanced acceleration research based on high-power lasers and plasma technologies. In a primary experiment based on the laser wakefield acceleration (LWFA) scheme, multi-hundred MeV electron beams having a reasonable quality are generated using 20-40 TW, 30 femtosecond laser pulses interacting independently with helium, neon, nitrogen and argon gas jet targets. The laser-plasma interaction conditions are optimized for stabilizing the electron beam generation from each type of gas. The electron beam pointing angle stability and divergence angle as well as the energy spectra from each gas jet are measured and compared.

Elsied, Ahmed M M; Li, Song; Mirzaie, Mohammad; Sokollik, Thomas; Zhang, Jie

2014-01-01T23:59:59.000Z

272

Fracture toughness of thick section dissimilar electron beam weld joints  

SciTech Connect

Microstructural investigations as well as crack tip opening displacement (CTOD) fracture toughness test based on elastic-plastic fracture mechanics were performed on single pass, full penetration similar and dissimilar electron beam (EB) welds of 40 mm thick 316L type austenitic steel and high alloyed fine tempered martensitic 9Cr 1Mo Nb V (P91 -ASTM A213) steel. The latter modified steel has been developed to fill up the gap between 12Cr steel and austenitic stainless steels with respect to the high temperature properties and better weldability. Furthermore, it shows a small thermal expansion coefficient and is not susceptible to stress corrosion cracking like the austenitic steel. The weldment properties were evaluated by microstructural analysis, microhardness, Charpy V- notch impact, and by newly developed flat microtensile specimens (0.5 mm thick). The dissimilar EB weld metal and HAZ of P91 steel has been shown to be microstructurally and mechanically distinct from both austenitic and martenistic parent metals. The use of microsized rectangular tensile specimens provides unique solution to the problem of the mechanical property determination of the narrow EB weld joint. The HAZ of the 9Cr1Mo steel exhibits extremely poor CTOD toughness properties in as-welded condition at room temperature. The CTOD values obtained were believed to be represent the intrinsic property of this zone, since the distance of the crack tip to the austenitic steel part was too large to receive a stress relaxation effect from low strength side on the crack tip (by accommodating the applied strains in the high toughness, lower strength 316L plate).

Kocak, M.; Junghans, E.

1994-12-31T23:59:59.000Z

273

Adapting High Brightness Relativistic Electron Beams for Ultrafast Science  

E-Print Network (OSTI)

Comparison of x-ray and electron sources for structuralJ. Luiten. Ultracold electron source. Phys. Rev. Lett. , 95:to non-relativistic electron sources is an inter- esting

Scoby, Cheyne Matthew

2012-01-01T23:59:59.000Z

274

System for tomographic determination of the power distribution in electron beams  

DOE Patents (OSTI)

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.

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

1995-01-17T23:59:59.000Z

275

System for tomographic determination of the power distribution in electron beams  

DOE Patents (OSTI)

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.

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

1995-01-01T23:59:59.000Z

276

System for tomographic determination of the power distribution in electron beams  

DOE Patents (OSTI)

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.

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

1995-11-21T23:59:59.000Z

277

Heating of a dense plasma with an intense relativistic electron beam: initial observations  

SciTech Connect

A dense (approx. 10/sup 17/ cm/sup -3/) plasma has been heated via the relativistic two-stream instability using a 3 MeV, intense (5 x 10/sup 5/ A/cm/sup 2/) electron beam. Evidence for heating has been obtained with diamagnetic loops, thin-foil witness plates, and a 2-channel, broad-band soft x-ray detector. Measurements of energy loss from the beam using calorimetry techniques have been attempted. The measured strong dependence of heating on beam transverse temperature and the very short interaction length (<4 cm) are consistent with beam-plasma coupling due to the relativistic electron-electron two-stream instability. Soft x-ray measurements made >100 ns after the beam pulse are consistent with a plasma temperature <150 eV and line emission near 80 to 90 eV.

Montgomery, M.D.; Parker, J.V.; Riepe, K.B.; Sheffield, R.L.

1981-01-01T23:59:59.000Z

278

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

SciTech Connect

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.

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

279

Surface roughening by electron beam heating D. Grozea, E. Landree, and L. D. Marks  

E-Print Network (OSTI)

Surface roughening by electron beam heating D. Grozea, E. Landree, and L. D. Marks Department atomic scale surface roughening of samples during the preparation of clean sili- con surfaces suitable

Marks, Laurence D.

280

Effect of electron beam irradiation and sugar content on kinetics of microbial survival  

E-Print Network (OSTI)

The killing effectiveness of electron beam irradiation has not been completely characterized. The type of microorganisms and the composition of food have a direct effect on the efficiency of this technology. The objectives of this study were...

Rodriguez Gonzalez, Oscar

2006-10-30T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


281

Electron-beam–deposited distributed polarization rotator for high-power laser applications  

Science Journals Connector (OSTI)

Electron-beam deposition of silica and alumina is used to fabricate distributed polarization rotators suitable for smoothing the intensity of large-aperture, high-peak-power lasers....

Oliver, J B; Kessler, T J; Smith, C; Taylor, B; Gruschow, V; Hettrick, J; Charles, B

2014-01-01T23:59:59.000Z

282

Nanometer-precision electron-beam lithography with applications in integrated optics  

E-Print Network (OSTI)

Scanning electron-beam lithography (SEBL) provides sub-10-nm resolution and arbitrary-pattern generation; however, SEBL's pattern-placement accuracy remains inadequate for future integrated-circuits and integrated-optical ...

Hastings, Jeffrey Todd, 1975-

2003-01-01T23:59:59.000Z

283

A Remark on the Method of Electron Beam Energy Measurement Using Laser Light Resonance Absorption  

E-Print Network (OSTI)

The problem of measuring of the electron beam energy by help of the laser light interaction with the electrons is discussed. It is shown that the orthogonal orientation of the laser beam with respect to the electron one, proposed in the present Note, may allow to perform this measurement in accordance with the physical nature of a formation of an electron quantum levels in a magnetic field. In result, the final formula, that expresses the beam energy through the strength of a magnetic field and the energy of the laser photon, gets a transparent physical meaning and do contain a less number of parameters (what may lead to an increase of the precision of the measurement). Some other sequences from this proposal, like the change of the geometry of the experimental set-up and the necessity of a new additional detector to register the products of the Compton scattering for monitoring of the beam energy measurements, are discussed also.

N. B. Skachkov

2005-03-01T23:59:59.000Z

284

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

DOE Patents (OSTI)

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.

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

2010-03-09T23:59:59.000Z

285

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

E-Print Network (OSTI)

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.

Othman, Mohamed; Capolino, Filippo

2014-01-01T23:59:59.000Z

286

Simulation of the Beam Dump for a High Intensity Electron Gun  

E-Print Network (OSTI)

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.

Doebert, S; Lefevre, T; Pepitone, K

2014-01-01T23:59:59.000Z

287

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

SciTech Connect

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.

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

288

Sheet beam model for intense space-charge: with application to Debye screening and the distribution of particle oscillation frequencies in a thermal equilibrium beam  

SciTech Connect

A one-dimensional Vlasov-Poisson model for sheet beams is reviewed and extended to provide a simple framework for analysis of space-charge effects. Centroid and rms envelope equations including image charge effects are derived and reasonable parameter equivalences with commonly employed 2D transverse models of unbunched beams are established. This sheet beam model is then applied to analyze several problems of fundamental interest. A sheet beam thermal equilibrium distribution in a continuous focusing channel is constructed and shown to have analogous properties to two- d three-dimensional thermal equilibrium models in terms of the equilibrium structure and Deybe screening properties. The simpler formulation for sheet beams is exploited to explicitly calculate the distribution of particle oscillation frequencies within a thermal equilibrium beam. It is shown that as space-charge intensity increases, the frequency distribution becomes broad, suggesting that beams with strong space-charge can have improved stability.

Lund, Steven M.; Friedman, Alex; Bazouin, Guillaume

2011-01-10T23:59:59.000Z

289

COUNTER PROPAGATION OF ELECTRON AND CO2 LASER BEAMS IN A PLASMA CHANNEL.  

SciTech Connect

A high-energy CO{sub 2} laser is channeled in a capillary discharge. Occurrence of guiding conditions at a relatively low plasma density (<10{sup 18} cm{sup -3}) is confirmed by MHD simulations. Divergence of relativistic electron beam changes depending on the plasma density. Counter-propagation of the electron and laser beams inside the plasma channel results in intense x-ray generation.

HIROSE,T.; POGORELSKY,I.V.; BEN ZVI,I.; YAKIMENKO,V.; KUSCHE,K.; SIDDONS,P.; KUMITA,T.; KAMIYA,Y.; ZIGLER,A.; GREENBERG,B.; ET AL

2002-11-12T23:59:59.000Z

290

Microwave radiation by a relativistic electron beam propagation through low?pressure air  

Science Journals Connector (OSTI)

Intense relativistic electron beams fired into air at varying pressures display a wide range of microwave signatures. These experiments held beam current energy and pulse length constant while varying gas pressure. Our observing window is 10 to 40 GHz. At low pressures (generated plasma frequencies. Power falls linearly with pressure above 20 mTorr until electron?Neutral collisions damp the emission at a few Torr. However weak 10 GHz emission appears at full atmospheric pressure.

S. Jordan; A. Ben?Amar Baranga; G. Benford; D. Tzach; K. Kato

1985-01-01T23:59:59.000Z

291

BEAM-CAVITY INTERACTION IN ELECTRON STORAGE RINGS  

E-Print Network (OSTI)

the effect of the ports on the energy loss. ]n section 2, weenergy loss due to higher modes is about 10 MeV if the beam portsports is studied in an independent computational method. The energy

Henkin, Bruce M.

2008-01-01T23:59:59.000Z

292

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

E-Print Network (OSTI)

A coherent x-ray or gamma ray can be created from a dense electron beam propagating through an intense laser undulator. It is analyzed by using the Landau damping theory which suits better than the conventional linear analysis for the free electron laser, as the electron beam energy spread is high. The analysis suggests that the currently available physical parameters would enable the generation of the coherent gamma ray of up to 100 keV. The electron quantum diffraction suppresses the FEL action, by which the maximum radiation energy to be generated is limited.

S. Son; S. J. Moon

2012-02-12T23:59:59.000Z

293

The effect of the driving frequency on the confinement of beam electrons and plasma density in low pressure capacitive discharges  

E-Print Network (OSTI)

The effect of changing the driving frequency on the plasma density and the electron dynamics in a capacitive radio-frequency argon plasma operated at low pressures of a few Pa is investigated by Particle in Cell/Monte Carlo Collisions simulations and analytical modeling. In contrast to previous assumptions the plasma density does not follow a quadratic dependence on the driving frequency in this non-local collisionless regime. Instead, a step-like increase at a distinct driving frequency is observed. Based on the analytical power balance model, in combination with a detailed analysis of the electron kinetics, the density jump is found to be caused by an electron heating mode transition from the classical $\\alpha$-mode into a low density resonant heating mode characterized by the generation of two energetic electron beams at each electrode per sheath expansion phase. These electron beams propagate through the bulk without collisions and interact with the opposing sheath. In the low density mode, the second bea...

Wilczek, S; Schulze, J; Schuengel, E; Brinkmann, R P; Derzsi, A; Korolov, I; Donkó, Z; Mussenbrock, T

2014-01-01T23:59:59.000Z

294

Immunogenicity and Effects on Fecal Microbiome of an Electron-Beam Inactivated Rhodococcus equi Vaccine in Neonatal Foals  

E-Print Network (OSTI)

May 2014 Major Subject: Biomedical Sciences Copyright 2014 Angela Ilha Bordin ii ABSTRACT Rhodococcus equi is a bacterium commonly isolated from soil that primarily causes pneumonia in foals and immunocompromised adult horses. Many... CTB Cholera toxin B e-beam Electron-beam EBRE 1 Electron-beam inactivated R. equi vaccine dose 1 EBRE 2 Electron-beam inactivated R. equi vaccine dose 2 ELISA Enzyme-linked immunosorbent assay FET Fisher’s exact test IFN-? Interferon gamma Ig...

Bordin, Angela Ilha

2014-05-03T23:59:59.000Z

295

Thermodynamic Bounds on Nonlinear Electrostatic Perturbations in Intense Charged Particle Beams  

SciTech Connect

This paper places a lowest upper bound on the field energy in electrostatic perturbations in single-species charged particle beams with initial temperature anisotropy (TllT? < 1). The result applies to all electrostatic perturbations driven by the natural anisotropies that develop in accelerated particle beams, including Harris-type electrostatic instabilities, known to limit the luminosity and minimum spot size attainable in experiments. The thermodynamic bound on the field perturbation energy of the instabilities is obtained from the nonlinear Vlasov-Poisson equations for an arbitrary initial distribution function, including the effects of intense self-fields, finite geometry and nonlinear processes. This paper also includes analytical estimates of the nonlinear bounds for space-charge-dominated and emittance-dominated anisotropic bi-Maxwellian distributions.

Nikolas C. Logan and Ronald C. Davidson

2012-07-18T23:59:59.000Z

296

A diagnosis of intense ion beam by CR-39 detectors analyzing the back scattered particles  

SciTech Connect

A new diagnosis method has been developed utilizing back scattered particles for high energy intense ion beams. The CR-39 detector mounted on the uniform back-scatterer was irradiated with {sup 4}He{sup 2+} ions with an energy 25 MeV/n, which is never recorded as etchable track in CR-39. We found that it is possible to diagnose by analyzing the etch pits on the rear surface of CR-39 that directly contacted on the back-scatterers. It turns out that most of etch pits in the rear surface are made by the backscattered particles by investigating the growth pattern of each etch pit with multi-step etching technique. This method allows simple diagnosis of the ion beam profile and intensity distribution in mixed radiation field such as laser-driven ion acceleration experiments.

Kanasaki, Masato; Yamauchi, Tomoya; Fukuda, Yuji; Sakaki, Hironao; Hori, Toshihiko; Tampo, Motonobu; Kurashima, Satoshi; Kamiya, Tomihiro; Oda, Keiji; Kondo, Kiminori [Graduate School of Maritime Sciences, Kobe University, Kobe 658-0022, Japan and Japan Atomic Energy Agency, Kizugawa, Kyoto 619-0215 (Japan); Graduate School of Maritime Sciences, Kobe University, Kobe 658-0022 (Japan); Japan Atomic Energy Agency, Kizugawa, Kyoto 619-0215 (Japan); Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Graduate School of Maritime Sciences, Kobe University, Kobe 658-0022 (Japan); Japan Atomic Energy Agency, Kizugawa, Kyoto 619-0215 (Japan)

2012-07-11T23:59:59.000Z

297

Electrostatic ion-acoustic-like instabilities in the solar wind with a backstreaming alpha particle beam  

SciTech Connect

Nonlinear electrostatic instabilities have been shown to occur frequently and under very different conditions in plasma with two ion beams such as the fast solar wind. These instabilities can be triggered when the phase velocity of electrostatic ion-acoustic waves propagating forward and backward relative to the interplanetary magnetic field overlaps due to the presence of a finite amplitude of circularly polarized wave. The instabilities can be triggered by waves supported by the same ion component, or by waves supported by different ion components. By assuming a beam of alpha particles moving backward relative to the external magnetic field, as observed in some events in the fast solar wind, it is shown that a very small negative drift velocity of the alpha particle beam relative to the core plasma--a few percent of the local Alfven velocity--can trigger a very rich variety of nonlinear electrostatic acousticlike instabilities. Their growth rates can be rather large and they persist for larger negative alpha particles drift velocities and temperatures.

Gomberoff, L. [Departamento de Fisica, Facultad de Ciencias, Universidad de Chile, Santiago (Chile); Gomberoff, K. [Department of Physics, Technion, Haifa 32000 (Israel); Deutsch, A. [Rafael, P.O. Box 2250, Haifa 31021 (Israel)

2010-06-15T23:59:59.000Z

298

Nano-electron beam induced current and hole charge dynamics through uncapped Ge nanocrystals  

SciTech Connect

Dynamics of hole storage in spherical Ge nanocrystals (NCs) formed by a two step dewetting/nucleation process on an oxide layer grown on an n-doped <001> silicon substrate is studied using a nano-electron beam induced current technique. Carrier generation is produced by an electron beam irradiation. The generated current is collected by an atomic force microscope--tip in contact mode at a fixed position away from the beam spot of about 0.5 {mu}m. This distance represents the effective diffusion length of holes. The time constants of holes charging are determined and the effect of the NC size is underlined.

Marchand, A.; El Hdiy, A.; Troyon, M. [Laboratoire de Recherche en Nanosciences, Bat. 6, case no 15, UFR Sciences, Universite de Reims Champagne Ardenne, 51687 Reims Cedex 2 (France); Amiard, G.; Ronda, A.; Berbezier, I. [IM2NP, Faculte des Sciences et Techniques, Campus de Saint Jerome - Case 142, Avenue Escadrille Normandie Niemen, 13397 Marseille Cedex 20 (France)

2012-04-16T23:59:59.000Z

299

A Plasma-Cathode Electron Source for Focused-Beam Generation in the Fore-Pump Pressure Range  

Science Journals Connector (OSTI)

A plasma electron source is described that forms a focused beam ... is generated in a hollow-cathode discharge. Electrons are extracted through a single emission hole in the anode. The source provides an electron

V. A. Burdovitsin; I. S. Zhirkov; E. M. Oks…

300

Miniature modified Faraday cup for micro electron beams  

DOE Patents (OSTI)

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.

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

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


301

Centroid and Envelope Dynamics of High-intensity Charged Particle Beams in an External Focusing Lattice and Oscillating Wobbler  

SciTech Connect

The centroid and envelope dynamics of a high-intensity charged particle beam are investigated as a beam smoothing technique to achieve uniform illumination over a suitably chosen region of the target for applications to ion-beam-driven high energy density physics and heavy ion fusion. The motion of the beam centroid projected onto the target follows a smooth pattern to achieve the desired illumination, for improved stability properties during the beam-target interaction. The centroid dynamics is controlled by an oscillating "wobbler", a set of electrically-biased plates driven by RF voltage. __________________________________________________

Hong Qin, Ronald C. Davidson and B. Grant Logan

2010-04-28T23:59:59.000Z

302

E-Print Network 3.0 - accelerator electron radiotherapy Sample...  

NLE Websites -- All DOE Office Websites (Extended Search)

Continuous Electron Beam Accelerator Facility, Newport News, Virginia (the Big... & Phenomenology Particle Astrophysics & Cosmology Accelerator Physics Health Physics...

303

Focused ion beam specimen preparation for electron holography of electrically biased thin film solar cells  

E-Print Network (OSTI)

, biased TEM specimen, thin film solar cell, FIB Thin films of hydrogenated Si (Si:H) can be used as active for electron holography of a thin film solar cell using conventional lift-out specimen preparation and a homeFocused ion beam specimen preparation for electron holography of electrically biased thin film

Dunin-Borkowski, Rafal E.

304

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

E-Print Network (OSTI)

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

Dekker, Cees

305

Supra-bubble regime for laser acceleration of cold electron beams in tenuous plasma  

E-Print Network (OSTI)

Supra-bubble regime for laser acceleration of cold electron beams in tenuous plasma V. I. Geyko,1 I 2010 Relativistic electrons can be accelerated by an ultraintense laser pulse in the "supra-bubble" regime, that is, in the blow-out regime ahead of the plasma bubble as opposed to the conventional method

306

Photo-production of scalar particles in the field of a circularly polarized laser beam  

E-Print Network (OSTI)

The photo-production of a pair of scalar particles in the presence of an intense, circularly polarized laser beam is investigated. Using the optical theorem within the framework of scalar quantum electrodynamics, explicit expressions are given for the pair production probability in terms of the imaginary part of the vacuum polarization tensor. Its leading asymptotic behavior is determined for various limits of interest. The influence of the absence of internal spin degrees of freedom is analyzed via a comparison with the corresponding probabilities for production of spin-1/2 particles; the lack of spin is shown to suppress the pair creation rate, as compared to the predictions from Dirac theory. Potential applications of our results for the search of minicharged particles are indicated.

Selym Villalba-Chávez; Carsten Müller

2012-08-17T23:59:59.000Z

307

Beam dynamics study of a 30?MeV electron linear accelerator to drive a neutron source  

SciTech Connect

An experimental neutron facility based on 32?MeV/18.47?kW electron linac has been studied by means of PARMELA simulation code. Beam dynamics study for a traveling wave constant gradient electron accelerator is carried out to reach the preferential operation parameters (E?=?30?MeV, P?=?18?kW, dE/E?particles). The whole linac comprises mainly E-gun, pre-buncher, buncher, and 2 accelerating columns. A disk-loaded, on-axis-coupled, 2?/3-mode type accelerating rf cavity is considered for this linac. After numerous optimizations of linac parameters, 32?MeV beam energy is obtained at the end of the linac. As high electron energy is required to produce acceptable neutron flux. The final neutron flux is estimated to be 5?×?10{sup 11}?n/cm{sup 2}/s/mA. Future development will be the real design of a 30?MeV electron linac based on S band traveling wave.

Kumar, Sandeep; Yang, Haeryong; Kang, Heung-Sik, E-mail: hskang@postech.ac.kr [Pohang Accelerator Laboratory, San31, Hyoja-dong, Pohang, Gyeongbuk 790-784 (Korea, Republic of)

2014-02-14T23:59:59.000Z

308

Uranium-contaminated soils: Ultramicrotomy and electron beam analysis  

SciTech Connect

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.

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

1994-04-01T23:59:59.000Z

309

Two-Screen Method for Determining Electron Beam Energy and Deflection from Laser Wakefield Acceleration  

SciTech Connect

Laser Wakefield Acceleration (LWFA) experiments have been performed at the Jupiter Laser Facility, Lawrence Livermore National Laboratory. In order to unambiguously determine the output electron beam energy and deflection angle at the plasma exit, we have implemented a two-screen electron spectrometer. This system is comprised of a dipole magnet followed by two image plates. By measuring the electron beam deviation from the laser axis on each plate, both the energy and deflection angle at the plasma exit are determined through the relativistic equation of motion.

Pollock, B B; Ross, J S; Tynan, G R; Divol, L; Glenzer, S H; Leurent, V; Palastro, J P; Ralph, J E; Froula, D H; Clayton, C E; Marsh, K A; Pak, A E; Wang, T L; Joshi, C

2009-04-24T23:59:59.000Z

310

Generation of a beam of fast electrons by tightly focusing a radially polarized ultrashort laser pulse  

SciTech Connect

The generation of an electron beam through longitudinal field acceleration from a tightly focused radially polarized (TM{sub 01}) laser mode is reported. The longitudinal field is generated by focusing a TM{sub 01} few-cycle laser pulse (1.8 {mu}m, 550 {mu}J, 15 fs) with a high numerical aperture parabola. The created longitudinal field in the focal region is intense enough to ionize atoms and accelerate electrons to 23 keV of energy from a low density oxygen gas. The characteristics of the electron beam are presented.

Payeur, S.; Fourmaux, S.; Schmidt, B. E.; MacLean, J. P.; Tchervenkov, C.; Legare, F.; Kieffer, J. C. [ALLS Facility, Institut National de la Recherche Scientifique Energie, Materiaux et Telecommunications (INRS-EMT), 1650, boul. Lionel-Boulet, Varennes, Quebec J3X 1S2 (Canada); Piche, M. [Centre d'Optique, Photonique et Laser (COPL), 2375 rue de la Terrasse, Universite Laval, Quebec G1V 0A6 (Canada)

2012-07-23T23:59:59.000Z

311

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

Energy.gov (U.S. Department of Energy (DOE)) Indexed Site

Up: 350,000 Pounds of Paper, 30,000 Particle Beams and 14 Days Up: 350,000 Pounds of Paper, 30,000 Particle Beams and 14 Days in Flight Geek-Up: 350,000 Pounds of Paper, 30,000 Particle Beams and 14 Days in Flight July 30, 2010 - 5:00pm Addthis Elizabeth Meckes Elizabeth Meckes Director of User Experience & Digital Technologies, Office of Public Affairs 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? Me neither. Thankfully, the Office of High Energy Physics in the Office of Science has released a full report about how accelerators are shaping America's future. The Z Accelerator from Sandia National Lab Find out more by downloading the full report here. How do you keep 350,000 pounds of paper out of landfills, create jobs, and

312

Demonstration of electron beam focusing by a laser-plasma lens  

E-Print Network (OSTI)

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.

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

313

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

DOE Patents (OSTI)

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.

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

2007-07-17T23:59:59.000Z

314

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

E-Print Network (OSTI)

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...

Tamma, Venkata Ananth

2013-01-01T23:59:59.000Z

315

Generation of a spin-polarized electron beam by multipoles magnetic fields  

E-Print Network (OSTI)

The propagation of an electron beam in the presence of transverse magnetic fields possessing integer topological charges is presented. The spin--magnetic interaction introduces a nonuniform spin precession of the electrons that gains a space-variant geometrical phase in the transverse plane proportional to the field's topological charge, whose handedness depends on the input electron's spin state. A combination of our proposed device with an electron orbital angular momentum sorter can be utilized as a spin-filter of electron beams in a mid-energy range. We examine these two different configurations of a partial spin-filter generator numerically. The results of these analysis could prove useful in the design of improved electron microscope.

Ebrahim Karimi; Vincenzo Grillo; Robert W. Boyd; Enrico Santamato

2013-06-10T23:59:59.000Z

316

Particle simulation of collision dynamics for ion beam injection into a rarefied gas  

SciTech Connect

This study details a comparison of ion beam simulations with experimental data from a simplified plasma test cell in order to study and validate numerical models and environments representative of electric propulsion devices and their plumes. The simulations employ a combination of the direct simulation Monte Carlo and particle-in-cell methods representing xenon ions and atoms as macroparticles. An anisotropic collision model is implemented for momentum exchange and charge exchange interactions between atoms and ions in order to validate the post-collision scattering behaviors of dominant collision mechanisms. Cases are simulated in which the environment is either collisionless or non-electrostatic in order to prove that the collision models are the dominant source of low- and high-angle particle scattering and current collection within this environment. Additionally, isotropic cases are run in order to show the importance of anisotropy in these collision models. An analysis of beam divergence leads to better characterization of the ion beam, a parameter that requires careful analysis. Finally, suggestions based on numerical results are made to help guide the experimental design in order to better characterize the ion environment.

Giuliano, Paul N.; Boyd, Iain D. [Department of Aerospace Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2013-03-15T23:59:59.000Z

317

HIGH ENERGY ELECTRON BEAM WELDING AND MATERIALS * # * *V.R. Dave, D. L. Goodman , T. W. Eagar , K. C. Russell  

E-Print Network (OSTI)

) ) HIGH ENERGY ELECTRON BEAM WELDING AND MATERIALS PROCESSING * # * *V.R. Dave·, D. L. Goodman , T. High energy electrons will penetrate several millimeters into most materials, and they allow for unique. W. Eagar , K. C. Russell ABSTRACT High Energy Electron Beams (HEEBs) offer a unique heat source

Eagar, Thomas W.

318

Model simulations of continuous ion injection into electron-beam ion source trap with slanted electrostatic mirrora...  

E-Print Network (OSTI)

Model simulations of continuous ion injection into electron-beam ion source trap with slanted developed by this group on DIONE electron-beam ion source EBIS .2­4 The most popular method of injecting 2 December 2007; published online 19 February 2008 The efficiency of trapping ions in an electron

319

BNL test electron beam ion source operation on a 100 kV platform ,,abstract...a...,b...  

E-Print Network (OSTI)

BNL test electron beam ion source operation on a 100 kV platform ,,abstract...a...,b... E. N. Beebe to build an electron beam ion source EBIS that will satisfy the requirements of the relativistic heavy ion program. Development studies continue to be carried out on the BNL test EBIS, a half-length full electron

320

Spatial resolution limits in electron-beam-induced deposition N. Silvis-Cividjian, C. W. Hagen,a  

E-Print Network (OSTI)

were written in a 200-kV STEM on a 30-nm SiN membrane. © 2005 American Institute of Physics. DOI: 10-beam instruments, such as scanning electron microscopes, scanning transmission electron microscopes STEM of a singular deposited dot or line, always exceeds the diameter of the electron beam. Until recently, no one

Silvis-Cividjian, Natalia

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


321

Compact UHV system for fabrication and in situ analysis of electron beam deposited structures using a focused low energy electron beam  

SciTech Connect

A compact UHV system was developed in order to fabricate and analyze micro- and nanostructures on surfaces in situ. The system includes a low energy electron gun which provides a minimum spot size of {approx}25 nm in a diameter using electrostatic lenses, a cylindrical mirror analyzer for Auger electron spectroscopy (AES) and electron energy loss spectroscopy (EELS), a low energy electron diffraction (LEED) optics, and a scintillation counter for scanning electron microscopy. Thus, we can analyze electronic states of specific microstructures on surfaces. In addition, we can fabricate microscopic structures artificially by means of scanning a focused electron beam. In this article, first we show the performance of the present analysis system. Next, we provide an example of the fabrication of iron microstructures by electron-induced deposition of iron pentacarbonyl [Fe(CO){sub 5}]. We successfully analyzed the amount and chemical states of deposited iron by AES in situ. We also investigated coverage dependence of electronic structure and surface periodic structure by EELS and LEED measurements, respectively. Thus, this system enables us to fabricate and analyze microscopic structures on surfaces in situ.

Kakefuda, Y.; Yamashita, Y.; Mukai, K.; Yoshinobu, J. [Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan)

2006-05-15T23:59:59.000Z

322

Simulative research on the expansion of cathode plasma in high-current electron beam diode  

SciTech Connect

The expansion of cathode plasma has long been recognized as a limiting factor in the impedance lifetime of high-current electron beam diode. Realistic modeling of such plasma is of great necessity in order to discuss the dynamics of cathode plasma. Using the method of particle-in-cell, the expansion of cathode plasma is simulated in this paper by a scaled-down diode model. It is found that the formation of cathode plasma increases the current density in the diode. This consequently leads to the decrease of the potential at plasma front. Once the current density has been increased to a certain value, the potential at plasma front would then be equal to or lower than the plasma potential. Then the ions would move towards the anode, and the expansion of cathode plasma is thereby formed. Different factors affecting the plasma expansion velocity are discussed in this paper. It is shown that the decrease of proton genatation rate has the benefit of reducing the plasma expansion velocity.

Xu Qifu; Liu Lie [College of Photoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2012-09-15T23:59:59.000Z

323

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

SciTech Connect

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.

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

324

Bimodal Electron Fluxes of Nearly Relativistic Electrons during the Onset of Solar Particle Events: 1. Observations  

E-Print Network (OSTI)

We report for several solar energetic particle events intensity and anisotropy measurements of energetic electrons in the energy range ~ 27 to ~ 500 keV as observed with the Wind and ACE spacecraft in June 2000. The observations onboard Wind show bimodal pitch angle distributions (PAD), whereas ACE shows PADs with one peak, as usually observed for impulsive injection of electrons at the Sun. During the time of observation Wind was located upstream of the Earth's bow shock, in the dawn - noon sector, at distances of ~ 40 to ~ 70 Earth radii away from the Earth, and magnetically well connected to the quasi-parallel bow shock, whereas ACE, located at the libration point L1, was not connected to the bow shock. The electron intensity-time profiles and energy spectra show that the backstreaming electrons observed at Wind are not of magnetospheric origin. The observations rather suggest that the bi-modal electron PADs are due to reflection or scattering at an obstacle located at a distance of less than ~ 150 Earth r...

Sun, Lingpeng; Klecker, Berndt; Krucker, Saem; Droege, Wolfgang

2010-01-01T23:59:59.000Z

325

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

DOE Patents (OSTI)

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.

Lasche, G.P.

1987-02-20T23:59:59.000Z

326

Longitudinal phase space manipulation of an ultrashort electron beam via THz IFEL interaction  

SciTech Connect

A scheme where a laser locked THz source is used to manipulate the longitudinal phase space of an ultrashort electron beam using an IFEL interaction is investigated. The efficiency of THz source based on the pulse front tilt optical rectification scheme is increased by cryogenic cooling to achieve sufficient THz power for compression and synchronization. Start-to-end simulations describing the evolution of the beam from the cathode to the compression point after the undulator are presented.

Moody, J. T.; Li, R. K.; Musumeci, P.; Scoby, C. M.; To, H. [Department of Physics and Astronomy, UCLA, Los Angeles California, 90095 (United States)

2012-12-21T23:59:59.000Z

327

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

DOE Patents (OSTI)

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.

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

1988-05-10T23:59:59.000Z

328

Single-crystal nanowires grown via electron-beam-induced deposition  

SciTech Connect

Electron-beam-induced deposition (EBID) is a useful technique for direct-writing of 3-dimensional dielectric, semiconductor, and metallic materials with nanoscale precision and resolution. The EBID process, however, has been limited in many cases because precursor byproducts (typically from organic precursors like W(CO)6) are incorporated into the deposited material resulting in contaminated and amorphous structures. In this manuscript, we have investigated the structure and composition of EBID tungsten nanostructures as-deposited from a tungsten hexafluoride (WF6) precursor. High-resolution transmission electron microscopy, electron diffraction and electron spectroscopy were employed to determine the effects that the electron beam scanning conditions have on the deposit characteristics. The results show that slow, one-dimensional lateral scanning produces textured -tungsten nanowire cores surrounded by an oxide secondary layer, while stationary vertical growth leads to single-crystal [100]-oriented W3O nanowires. Furthermore we correlate how the growth kinetics affect the resultant nanowire structure and composition.

Klein, Kate L [ORNL; Randolph, Steven J [ORNL; Fowlkes, Jason Davidson [ORNL; Allard Jr, Lawrence Frederick [ORNL; Meyer III, Harry M [ORNL; Simpson, Michael L [ORNL; Rack, Philip D [ORNL

2008-01-01T23:59:59.000Z

329

Controllable high-quality electron beam generation by phase slippage effect in layered targets  

E-Print Network (OSTI)

The bubble structure generated by laser and plasma interactions changes in size depending on the local plasma density. The self injection electrons position with respect to wakefield can be controlled by tailoring the longitudinal plasma density. A regime to enhance the energy of the wakefield accelerated electrons and improve the beam quality is proposed and achieved using layered plasmas with increasing densities. Both the wakefield size and the electron bunch duration are significantly contracted in this regime. The electrons remain in the strong acceleration phase of the wakefield while their energy spread decreases because of their tight spatial distribution. An electron beam of 0.5GeV with less than 0.01 energy spread is obtained through 2.5D PIC simulations.

Yu, Q; Li, X F; Huang, S; Zhang, F; Kong, Q; Ma, Y Y; Kawata, S

2014-01-01T23:59:59.000Z

330

Electron Beam Irradiation for Improving Safety of Fruits and Vegetables  

E-Print Network (OSTI)

. An alternative may be irradiation which is emerging as a promising tool to enhance safety and extend shelf life of fresh and fresh cut produce. Gamma rays have been the most extensively studied form of irradiation and have been successfully applied to spices..., tubers, grains and meat products for the space program. However, consumer reluctance has limited its application over a broad range of food stuffs. As a result, alternate irradiation technologies such as e-beam and X-rays are attracting attention...

Adavi, Megha Sarthak

2012-07-16T23:59:59.000Z

331

Optical emission from a high-refractive-index waveguide excited by a traveling electron beam  

SciTech Connect

An optical emission scheme was demonstrated, in which a high-refractive-index waveguide is excited by a traveling electron beam in a vacuum environment. The waveguide was made of Si-SiO{sub 2} layers. The velocity of light propagating in the waveguide was slowed down to 1/3 of that in free space due to the high refractive index of Si. The light penetrated partly into the vacuum in the form of a surface wave. The electron beam was emitted from an electron gun and propagated along the surface of the waveguide. When the velocity of the electron coincided with that of the light, optical emission was observed. This emission is a type of Cherenkov radiation and is not conventional cathode luminescence from the waveguide materials because Si and SiO{sub 2} are transparent to light at the emitted wavelength. This type of emission was observed in an optical wavelength range from 1.2 to 1.6 {mu}m with an electron acceleration voltage of 32-42 kV. The characteristics of the emitted light, such as the polarization direction and the relation between the acceleration voltage of the electron beam and the optical wavelength, coincided well with the theoretical results. The coherent length of an electron wave in the vacuum was confirmed to be equal to the electron spacing, as found by measuring the spectral profile of the emitted light.

Kuwamura, Yuji; Yamada, Minoru; Okamoto, Ryuichi; Kanai, Takeshi; Fares, Hesham [Division of Electrical Engineering and Computer Science, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192 (Japan)

2008-11-15T23:59:59.000Z

332

Calculation of synchrotron radiation from high intensity electron beam at eRHIC  

SciTech Connect

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.

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

2012-05-20T23:59:59.000Z

333

Recycler Electron Cooling Project: Mechanical vibrations in the Pelletron and their effect on the beam  

SciTech Connect

The Fermilab's Recycler ring will employ an electron cooler to cool stored 8.9 GeV antiprotons [1]. The cooler is based on an electrostatic accelerator, Pelletron [2], working in an energy-recovery regime. A full-scale prototype of the cooler has been assembled and commissioned in a separate building [3]. The main goal of the experiments with the prototype was to demonstrate stable operation with a 3.5 MeV, 0.5 A DC electron beam while preserving a high beam quality in the cooling section. The quality is characterized, first of all, by a spread of electron velocities in the cooling section, which may be significantly affected by mechanical vibration of the Pelletron elements. This paper describes the results of vibration measurements in the Pelletron terminal and correlates them with the beam motion in the cooling section.

Kazakevich, Grigory M.; Burov, A.; Boffo, C.; Joireman, P.; Saewert, G.; Schmidt, C.W.; Shemyakin, A.; /Fermilab

2005-07-01T23:59:59.000Z

334

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

DOE Patents (OSTI)

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.

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

1980-01-03T23:59:59.000Z

335

Probing the Transverse Coherence of an Undulator X-Ray Beam Using Brownian Particles  

SciTech Connect

We present a novel method to map the two-dimensional transverse coherence of an x-ray beam using the dynamical near-field speckles formed by scattering from colloidal particles. Owing to the statistical nature of the method, the coherence properties of synchrotron radiation from an undulator source is obtained with high accuracy. The two-dimensional complex coherence function is determined at the sample position and the imaging optical scheme further allowed us to evaluate the coherence factor at the undulator output despite the aberrations introduced by the focusing optics.

Alaimo, M. D. [Dipartimento di Fisica, Universita di Milano, I-20133 Milano, CNISM (Italy); European Synchrotron Radiation Facility, BP-220, F-38043 Grenoble (France); Potenza, M. A. C.; Manfredda, M.; Giglio, M. [Dipartimento di Fisica, Universita di Milano, I-20133 Milano, CNISM (Italy); Geloni, G. [Deutsches Elektronen-Synchrotron and European XFEL GmbH, D-22607 Hamburg (Germany); Sztucki, M.; Narayanan, T. [European Synchrotron Radiation Facility, BP-220, F-38043 Grenoble (France)

2009-11-06T23:59:59.000Z

336

Parametric Channeling Radiation and its Application to the Measurement of Electron Beam Energy  

SciTech Connect

We have proposed a method for observing parametric channeling radiation (PCR) and of applying it to the measurement of electron beam energy. The PCR process occurs if the energy of the channeling radiation coincides with the energy of the parametric X-ray radiation (PXR). The PCR process can be regarded as the diffraction of 'virtual channeling radiation'. We developed a scheme for beam energy measurement and designed an experimental setup. We also estimated the beam parameters, and calculated the angular distributions of PXR and PCR. These considerations indicate that the observation of PCR is promising.

Takabayashi, Y. [SAGA Light Source, 8-7 Yayoigaoka, Tosu, Saga 841-0005 (Japan)

2010-06-23T23:59:59.000Z

337

Negative ion beam injection apparatus with magnetic shield and electron removal means  

DOE Patents (OSTI)

A negative ion source is constructed to produce H.sup.- ions without using Cesium. A high percentage of secondary electrons that typically accompany the extracted H.sup.- are trapped and eliminated from the beam by permanent magnets in the initial stage of acceleration. Penetration of the magnetic field from the permanent magnets into the ion source is minimized. This reduces the destructive effect the magnetic field could have on negative ion production and extraction from the source. A beam expansion section in the extractor results in a strongly converged final beam.

Anderson, Oscar A. (Berkeley, CA); Chan, Chun F. (Hayward, CA); Leung, Ka-Ngo (Hercules, CA)

1994-01-01T23:59:59.000Z

338

A monolithic relativistic electron beam source based on a dielectric laser accelerator structure  

SciTech Connect

Work towards a monolithic device capable of producing relativistic particle beams within a cubic-centimeter is detailed. We will discuss the Micro-Accelerator Platform (MAP), an optical laser powered dielectric accelerator as the main building block of this chip-scale source along with a field enhanced emitter and a region for sub-relativistic acceleration.

McNeur, Josh; Carranza, Nestor; Travish, Gil; Yin Hairong; Yoder, Rodney [UCLA Dept. of Physics and Astronomy, Los Angeles, CA 90095 (United States); College of Physical Electronics, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054 (China); Manhattanville College, Physics Dept., 2900 Purchase St., Purchase, NY 10577 (United States)

2012-12-21T23:59:59.000Z

339

New generation electronics applied to beam position monitors  

SciTech Connect

Cellular telephones and global positioning system (GPS) satellite receivers are examples of modern rf engineering. Taking some inspiration from those designs, a precision signal-processor module for beam position monitors was developed. It features a heterodyne receiver (100 MHz to 1 GHz) with more than 90 dB dynamic range. Four multiplexed input channels are able to resolve signal differences lower than 0.0005 dB with good long-term stability. This corresponds to sub-micron resolution when used with a beam position pick-up with 40 mm free aperture. The paper concentrates on circuit design and modern dynamic testing methods, used first during development and later for production tests. The frequency synthesizer of the local oscillator, the phase-locked synchronous detector, and the low-noise preamplifier with automatic gain control are discussed. Other topics are design for immunity to electromagnetic interference to ensure reliable operation in an accelerator environment. {copyright} {ital 1997 American Institute of Physics.}

Unser, K.B. [BERGOZ Precision Beam Instrumentation, F-01170 Crozet (France)

1997-01-01T23:59:59.000Z

340

Impact of electron collision mixing on the delay times of an electron beam excited atomic xenon laser  

SciTech Connect

The atomic xenon (5d {r arrow} 6p) infrared laser has been experimentally and theoretically investigated using a short pulse (30 ns) high power (1-10 MW/cm{sup 3}) coaxial electron beam excitation source. In most cases, laser oscillation is not observed during the e-beam current pulse. Laser pulses of 100's of ns duration are subsequently obtained, however, with oscillation beginning 60-800 ns after the current pulse terminates. Results from a computer model for the xenon laser reproduce the experimental values, and show that oscillation begins when the fractional electron density decays below a critical value of {approx} 0.2-0.8 {times} 10{sup 6}. These results lend credance to the proposal that electron collision mixing of the laser levels limits the maximum value of specific power deposition which may be used to efficiently excite the atomic xenon laser on a quasi-CW basis.

Peters, P.J. (Dept. of Applied Physics, Univ. of Twente, 7500 AE Enshede (NL)); Lan, Y.F. (Inst. of Electronics, Beijing (CN)); Ohwa, M. (Dept. of Electrical Engineering, Keio Univ., Yokahama (JP)); Kushner, M.J. (Dept. of Electrical and Computer Engineering, Univ. of Illinois, Urbana, IL (US))

1990-11-01T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


341

Variation of Langmuir wave polarization with electron beam speed in type III radio bursts  

SciTech Connect

Observations by the twin STEREO spacecraft of in-situ electric field waveforms and radio signatures associated with type III radio bursts have demonstrated that the polarization of electron beam-driven waves near the local plasma frequency depends strongly on the speed of the driving electron beam. We expand upon a previous study by including all radio bursts with in-situ waveforms observed by STEREO in 2011. The expanded data set contains five times more radio bursts (35 up from 7) and three times as many Langmuir waves (663 up from 168). While this expanded study supports the results of the original study, that faster (slower) beam electrons drive waves with strong (weak) electric fields perpendicular to the local magnetic field, the larger data set emphasizes that the observation of strong perpendicular electric fields at high electron beam speeds is probabilistic rather than definite. This property supports the interpretation of wave polarization dependence on beam speed as Langmuir/z-mode waves shifted to small wave number through interaction with turbulent solar wind density fluctuations.

Malaspina, David M. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States); Cairns, Iver H. [School of Physics, University of Sydney, New South Wales 2006 (Australia); Ergun, Robert E. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States) and Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80303 (United States)

2013-06-13T23:59:59.000Z

342

Study of beam transverse properties of a thermionic electron gun for application to a compact THz free electron laser  

SciTech Connect

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.

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

343

Conceptual design for an electron-beam heated hypersonic wind tunnel  

SciTech Connect

There is a need for hypersonic wind-tunnel testing at about mach 10 and above using natural air and simulating temperatures and pressures which are prototypic of flight at 50 km altitude or below. With traditional wind-tunnel techniques, gas cooling during expansion results in exit temperatures which are too low. Miles, et al., have proposed overcoming this difficulty by heating the air with a laser beam as it expands in the wind-tunnel nozzle. This report discusses an alternative option of using a high-power electron beam to heat the air as it expands. In the e-beam heating concept, the electron beam is injected into the wind-tunnel nozzle near the exit and then is guided upstream toward the nozzle throat by a strong axial magnetic field. The beam deposits most of its power in the dense air near the throat where the expansion rate is greatest. A conceptual design is presented for a large-scale system which achieves Mach 14 for 0.1 seconds with an exit diameter of 2.8 meters. It requires 450 MW of electron beam power (5 MeV at 90 A). The guiding field is 500 G for most of the transport length and increases to 100 kG near the throat to converge the beam to a 1.0-cm diameter. The beam generator is a DC accelerator using a Marx bank (of capacitors) and a diode stack with a hot cathode. 14 refs. 38 figs., 9 tabs.

Lipinski, R.J.; Kensek, R.P.

1997-07-01T23:59:59.000Z

344

Visualization of Trajectories of Electron Beams Emitted by an Ion Source with Closed Electron Drift  

E-Print Network (OSTI)

that this additional electron source is not able to provideare a source of additional electrons that partiallyEmitted by an Ion Source with Closed Electron Drift Ivan V.

Bordenjuk, Ian V.; Institue of Physics, National Academy of Sciences of Ukraine

2008-01-01T23:59:59.000Z

345

A study of electron recombination using highly ionizing particles...  

NLE Websites -- All DOE Office Websites (Extended Search)

mobility * Electron MFP 20 nm * Onsager radius 130 nm (E Coulomb E thermal ) * No vibration levels available 1 nsec thermalization time * Electrons in Coulomb field or...

346

Electron  

NLE Websites -- All DOE Office Websites (Extended Search)

to measure the electron density gradient and its fluctuations. Two separate laser beams with slight spatial offset and frequency difference are coupled into a single mixer...

347

Electron Beam Pasteurization of Fresh Fruit for Neutropenic Diet: E-beam Reduces Bioburden While Preserving Quality  

E-Print Network (OSTI)

encouragement and assistance whenever it was needed. I also want to give a special thanks Mickey and Kayla at the National Center for Electron Beam Research Center whom kindly assisted me with irradiating my samples. Thanks also to Dr. Patil for allowing... me to use his lab to perform many experiments for which would be impossible without them. Special thanks to Ram Uckoo and Dr. J.K. for teaching and guiding me throughout my time there. I am very grateful to Tom Jondiko in Dr. Awika?s lab...

Smith, Bianca R

2013-08-09T23:59:59.000Z

348

Attachment of Salmonella on cantaloupe and effect of electron beam irradiation on quality and safety of sliced cantaloupe  

E-Print Network (OSTI)

effectively by irradiation but there was no significant effect on reduction of yeasts. Our results show that electron beam irradiation in combination with chemical sanitizers is effective in decontamination of fresh-cut produce. Electron microscopy images...

Palekar, Mangesh Prafull

2006-04-12T23:59:59.000Z

349

Virtual anode as a source of low-frequency oscillations of a high-current electron beam  

Science Journals Connector (OSTI)

We have studied the transport of a relativistic electron beam with supercritical current in a cylindrical drift chamber in the presence of an ion flux. A theoretical analysis of the electron-ion flux dynamics ...

1 P. I. Markov; I. N. Onishchenko; G. V. Sotnikov

2003-12-01T23:59:59.000Z

350

Gamma electron vertex imaging and application to beam range verification in proton therapy  

SciTech Connect

Purpose: This paper describes a new gamma-ray imaging method, ''gamma electron vertex imaging (GEVI)'', which can be used for precise beam range verification in proton therapy. Methods: In GEVI imaging, the high-energy gammas from a source or nuclear interactions are first converted, by Compton scattering, to electrons, which subsequently are traced by hodoscopes to determine the location of the gamma source or the vertices of the nuclear interactions. The performance of GEVI imaging for use in-beam range verification was evaluated by Monte Carlo simulations employing geant4 equipped with the QGSP{sub B}IC{sub H}P physics package. Results: Our simulation results show that GEVI imaging can determine the proton beam range very accurately, within 2-3 mm of error, even without any sophisticated analysis. The results were obtained under simplified conditions of monoenergetic pencil beams stopped in a homogeneous phantom and on the basis of the obtained results it is expected to achieve submillimeter accuracy in proton beam range measurement. Conclusions: If future experimental work confirms the simulated results presented in this paper, the use of GEVI imaging is expected to have a great potential in increasing the accuracy of proton beam range verification in a patient, resulting in significant improvement of treatment effectiveness by enabling tight conformation of radiation dose to the tumor volume and patient safety.

Hyeong Kim, Chan; Hyung Park, Jin; Seo, Hee; Rim Lee, Han [Department of Nuclear Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of)

2012-02-15T23:59:59.000Z

351

Transverse Beam Spin Asymmetries at Backward Angles in Elastic Electron-Proton and Quasi-elastic Electron-Deuteron Scattering  

E-Print Network (OSTI)

We have measured the beam-normal single-spin asymmetries in elastic scattering of transversely polarized electrons from the proton, and performed the first measurement in quasi-elastic scattering on the deuteron, at backward angles (lab scattering angle of 108 degrees) for Q2 = 0.22 GeV^2/c^2 and 0.63 GeV^2/c^2 at beam energies of 362 MeV and 687 MeV, respectively. The asymmetry arises due to the imaginary part of the interference of the two-photon exchange amplitude with that of single photon exchange. Results for the proton are consistent with a model calculation which includes inelastic intermediate hadronic (piN) states. An estimate of the beam-normal single-spin asymmetry for the scattering from the neutron is made using a quasi-static deuterium approximation, and is also in agreement with theory.

The G0 Collaboration; D. Androi?; D. S. Armstrong; J. Arvieux; S. L. Bailey; D. H. Beck; E. J. Beise; J. Benesch; F. Benmokhtar; L. Bimbot; J. Birchall; P. Bosted; H. Breuer; C. L. Capuano; Y. -C. Chao; A. Coppens; C. A. Davis; C. Ellis; G. Flores; G. Franklin; C. Furget; D. Gaskell; M. T. W. Gericke; J. Grames; G. Guillard; J. Hansknecht; T. Horn; M. K. Jones; P. M. King; W. Korsch; S. Kox; L. Lee; J. Liu; A. Lung; J. Mammei; J. W. Martin; R. D. McKeown; A. Micherdzinska; M. Mihovilovic; H. Mkrtchyan; M. Muether; S. A. Page; V. Papavassiliou; S. F. Pate; 10 S. K. Phillips; P. Pillot; M. L. Pitt; M. Poelker; B. Quinn; W. D. Ramsay; J. -S. Real; J. Roche; P. Roos; J. Schaub; T. Seva; N. Simicevic; G. R. Smith; D. T. Spayde; M. Stutzman; R. Suleiman; V. Tadevosyan; W. T. H. van Oers; M. Versteegen; E. Voutier; W. Vulcan; S. P. Wells; S. E. Williamson; S. A. Wood; B. Pasquini; M. Vanderhaeghen

2011-06-16T23:59:59.000Z

352

Highly coherent electron beam from a laser-triggered tungsten needle tip  

E-Print Network (OSTI)

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...

Ehberger, Dominik; Eisele, Max; Krüger, Michael; Noe, Jonathan; Högele, Alexander; Hommelhoff, Peter

2014-01-01T23:59:59.000Z

353

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

SciTech Connect

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.

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

354

Transverse resistive wall effects on the dynamics of a bunched electron beam  

Science Journals Connector (OSTI)

In the wigglers of future free-electron lasers, the electron beam will be required to travel over a length of 10 m or more in pipes with small diameters. Transverse resistive wall effects could lead to beam breakup during this transport. To investigate this possibility, the equation of motion for a bunched beam is solved analytically. Results show that a steady-state solution is reached for times larger than the diffusion time. This solution can either oscillate or grow exponentially with the length of the pipe, depending on the relative magnitudes of the resistive wall effect and the focusing force in the wiggler. The magnitude of the resistive wall effect depends on the pipe radius b (it increases as 1/b2) but is independent of the thickness and conductivity of the pipe. The thickness and conductivity affect only the time required to reach the steady-state solution. The possibility of a significant transient is also discussed.

Govindan Rangarajan and K. C. D. Chan

1989-05-01T23:59:59.000Z

355

Antimicrobial packaging system for optimization of electron beam irradiation of fresh produce  

E-Print Network (OSTI)

This study evaluated the potential use of an antimicrobial packaging system in combination with electron beam irradiation to enhance quality of fresh produce. Irradiated romaine lettuce up to 3.2 kGy showed negligible (p > 0.05) changes in color...

Han, Jaejoon

2006-10-30T23:59:59.000Z

356

Progress towards a 200 MW electron beam accelerator for the RDHWT/Mariah II Program.  

SciTech Connect

The Radiatively Driven Hypersonic Wind Tunnel (RDHWT) program requires an unprecedented 2-3 MeV electron beam energy source at an average beam power of approximately 200MW. This system injects energy downstream of a conventional supersonic air nozzle to minimize plenum temperature requirements for duplicating flight conditions above Mach 8 for long run-times. Direct-current electron accelerator technology is being developed to meet the objectives of a radiatively driven Mach 12 wind tunnel with a free stream dynamic pressure q=2000 psf. Due to the nature of research and industrial applications, there has never been a requirement for a single accelerator module with an output power exceeding approximately 500 kW. Although a 200MW module is a two-order of magnitude extrapolation from demonstrated power levels, the scaling of accelerator components to this level appears feasible. Accelerator system concepts are rapidly maturing and a clear technology development path has been established. Additionally, energy addition experiments have been conducted up to 800 kW into a supersonic airflow. This paper will discuss progress in the development of electron beam accelerator technology as an energy addition source for the RDHWT program and results of electron beam energy addition experiments conducted at Sandia National Laboratories.

Lockner, Thomas Ramsbeck; Reed, Kim Warren; Pena, Gary Edward; Schneider, Larry X.; Lipinski, Ronald J.; Glover, Steven Frank

2004-06-01T23:59:59.000Z

357

High energy electron beam curing of epoxy resin systems incorporating cationic photoinitiators  

DOE Patents (OSTI)

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.

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

358

Downward current electron beam observed by Cluster and FAST Andrew N. Wright,1  

E-Print Network (OSTI)

Downward current electron beam observed by Cluster and FAST Andrew N. Wright,1 Christopher J. Owen and 0.05 mAmÃ?2 , respectively, and j/B is conserved along a current filament. Citation: Wright, A. N., C.g., Temerin and Carlson [1998] and Cran-McGreehin and Wright [2005a, 2005b]. However, other events seem

California at Berkeley, University of

359

Design and characterization of electron beam focusing for X-ray generation in novel medical imaging architecture  

SciTech Connect

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.

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

360

Ion-beam and electron-beam irradiation of synthetic britholite S. Utsunomiya a  

E-Print Network (OSTI)

on previously amorphized britholite (N56) with an electron flux of 1.07 · 1025 e� /m2 /s. The ionizing radiation resulted in recrystallization at the absorbed dose of 6.2 · 1013 Gy. This result suggests that the ionizingV Kr2þ and 1.5 MeV Xeþ over the temperature range of 50­973 K. The process of ion irradiation

Utsunomiya, Satoshi

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


361

Precision cutting of nanotubes with a low-energy electron beam T. D. Yuzvinsky, A. M. Fennimore, W. Mickelson, C. Esquivias, and A. Zettla  

E-Print Network (OSTI)

Precision cutting of nanotubes with a low-energy electron beam T. D. Yuzvinsky, A. M. Fennimore, W remove material from carbon and boron nitride nanotubes using the low-energy focused electron beam nanotubes are controllably damaged using the low-energy focused electron beam of a scanning electron

Yuzvinsky, Tom

362

Quasi-monoenergetic electron beams production in a sharp density transition  

SciTech Connect

Using a laser plasma accelerator, experiments with a 80 TW and 30 fs laser pulse demonstrated quasi-monoenergetic electron spectra with maximum energy over 0.4 GeV. This is achieved using a supersonic He gas jet and a sharp density ramp generated by a high intensity laser crossing pre-pulse focused 3 ns before the main laser pulse. By adjusting this crossing pre-pulse position inside the gas jet, among the laser shots with electron injection, more than 40% can produce quasi-monoenergetic spectra. This could become a relatively straight forward technique to control laser wakefield electron beams parameters.

Fourmaux, S.; Lassonde, P.; Lebrun, G.; Kieffer, J. C. [INRS-EMT, Universite du Quebec, 1650 Lionel Boulet, Varennes, Quebec J3X 1S2 (Canada); Ta Phuoc, K.; Corde, S.; Malka, V.; Rousse, A. [Laboratoire d'Optique Appliquee, ENSTA ParisTech - CNRS UMR7639 - Ecole Polytechnique ParisTech, Chemin de la Huniere, 91761 Palaiseau (France)

2012-09-10T23:59:59.000Z

363

Turtle With Mad Input (trace Unlimited Rays Through Lumped Elements) -- A Computer Program For Simulating Charged Particle Beam Transport Systems And Decay Turtle Including Decay Calculations  

E-Print Network (OSTI)

Turtle With Mad Input (trace Unlimited Rays Through Lumped Elements) -- A Computer Program For Simulating Charged Particle Beam Transport Systems And Decay Turtle Including Decay Calculations

Carey, D C

1999-01-01T23:59:59.000Z

364

Development of a compact thermal lithium atom beam source for measurements of electron velocity distribution function anisotropy in electron cyclotron resonance plasmas  

SciTech Connect

The anisotropy of the electron velocity distribution function (EVDF) in plasmas can be deduced from the polarization of emissions induced by anisotropic electron-impact excitation. In this paper, we develop a compact thermal lithium atom beam source for spatially resolved measurements of the EVDF anisotropy in electron cyclotron resonance (ECR) plasmas. The beam system is designed such that the ejected beam has a slab shape, and the beam direction is variable. The divergence and flux of the beam are evaluated by experiments and calculations. The developed beam system is installed in an ECR plasma device with a cusp magnetic field, and the LiI 2s–2p emission (670.8 nm) is observed in low-pressure helium plasma. The two-dimensional distributions of the degree and direction of the polarization in the LiI emission are measured by a polarization imaging system. The evaluated polarization distribution suggests the spatial variation of the EVDF anisotropy.

Nishioka, T.; Shikama, T.; Nagamizo, S.; Fujii, K.; Hasuo, M. [Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto 615-8540 (Japan)] [Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto 615-8540 (Japan); Zushi, H. [Research Institute for Applied Mechanics, Kyushu University, Fukuoka 816-8580 (Japan)] [Research Institute for Applied Mechanics, Kyushu University, Fukuoka 816-8580 (Japan); Uchida, M.; Tanaka, H.; Maekawa, T. [Department of Fundamental Energy Science, Graduate School of Energy Science, Kyoto University, Kyoto 606-8502 (Japan)] [Department of Fundamental Energy Science, Graduate School of Energy Science, Kyoto University, Kyoto 606-8502 (Japan); Iwamae, A. [Research Center for Development of Far-Infrared Region, Fukui University, Fukui 910-8507 (Japan)] [Research Center for Development of Far-Infrared Region, Fukui University, Fukui 910-8507 (Japan)

2013-07-15T23:59:59.000Z

365

Spectrum bandwidth narrowing of Thomson scattering X-rays with energy chirped electron beams from laser wakefield acceleration  

SciTech Connect

We study incoherent Thomson scattering between an ultrashort laser pulse and an electron beam accelerated from a laser wakefield. The energy chirp effects of the accelerated electron beam on the final radiation spectrum bandwidth are investigated. It is found that the scattered X-ray radiation has the minimum spectrum width and highest intensity as electrons are accelerated up to around the dephasing point. Furthermore, it is proposed that the electron acceleration process inside the wakefield can be studied by use of 90° Thomson scattering. The dephasing position and beam energy chirp can be deduced from the intensity and bandwidth of the scattered radiation.

Xu, Tong; Chen, Min, E-mail: minchen@sjtu.edu.cn; Li, Fei-Yu; Yu, Lu-Le [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)] [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Sheng, Zheng-Ming, E-mail: zmsheng@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China) [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Zhang, Jie [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China) [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Beijing National Laboratory of Condensed Matter Physics, Institute of Physics, CAS, Beijing 100190 (China)

2014-01-06T23:59:59.000Z

366

Study of magnetic configuration effects on plasma boundary and measurement of edge electron density in the spherical tokamak compact plasma wall interaction experimental device using Li sheet beam  

SciTech Connect

Two-dimensional lithium beam imaging technique has been applied in the spherical tokamak CPD (compact plasma wall interaction experimental device) to study the effects of magnetic field configurations on rf plasma boundary in the absence of any plasma current, and also for the measurement of a two-dimensional edge electron density profile. With the present working condition of the diagnostics, the minimum measured electron density can be {approx}1.0x10{sup 16} m{sup -3}; this is considered to be the definition for the plasma boundary. The performance of the lithium sheet beam is absolutely calibrated using a quartz crystal monitor. Experimental results reveal that magnetic field configuration, either mirror or so-called null, critically affects the rf plasma boundary. A sharp lower boundary is found to exist in magnetic null configuration, which is quite different from that in the weak mirror configuration. Theoretical calculations of particle drift orbit and magnetic connection length (wall-to-wall) suggest that only mirror trapped particles are confined within a region where the magnetic connection length is {approx}4.0 m or more. A two-dimensional edge electron density profile is obtained from the observed Li I intensity profile. Overdense plasma formation is discussed from the viewpoint of mode conversion of rf wave into electron Bernstein wave and its dependence on the electron density profile.

Bhattacharyay, R.; Inada, Y.; Kikukawa, T.; Watanabe, S.; Sasaki, K.; Ryoukai, T. [Interdisciplinary Graduate School of Engineering Science, Kyushu University, Kasuga, Fukuoka 816 8580 (Japan); Zushi, H.; Hasegawa, M.; Hanada, K.; Sato, K. N.; Nakamura, K.; Sakamoto, M.; Idei, H.; Yoshinaga, T.; Kawasaki, S.; Nakashima, H.; Higashijima, A. [Research Institute of Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816 8580 (Japan); Morisaki, T. [National Institute for Fusion Science, Toki 509 5292 (Japan)

2008-02-15T23:59:59.000Z

367

Study of magnetic configuration effects on plasma boundary and measurement of edge electron density in the spherical tokamak compact plasma wall interaction experimental device using Li sheet beam  

Science Journals Connector (OSTI)

Two-dimensional lithium beam imaging technique has been applied in the spherical tokamak CPD (compact plasma wall interaction experimental device) to study the effects of magnetic field configurations on rf plasma boundary in the absence of any plasma current and also for the measurement of a two-dimensional edge electron density profile. With the present working condition of the diagnostics the minimum measured electron density can be ? 1.0 × 10 16 m ? 3 ; this is considered to be the definition for the plasma boundary. The performance of the lithium sheet beam is absolutely calibrated using a quartz crystal monitor. Experimental results reveal that magnetic field configuration either mirror or so-called null critically affects the rf plasma boundary. A sharp lower boundary is found to exist in magnetic null configuration which is quite different from that in the weak mirror configuration. Theoretical calculations of particle drift orbit and magnetic connection length (wall-to-wall) suggest that only mirror trapped particles are confined within a region where the magnetic connection length is ? 4.0 m or more. A two-dimensional edge electron density profile is obtained from the observed Li I intensity profile. Overdense plasma formation is discussed from the viewpoint of mode conversion of rf wave into electron Bernstein wave and its dependence on the electron density profile.

R. Bhattacharyay; H. Zushi; T. Morisaki; Y. Inada; T. Kikukawa; S. Watanabe; K. Sasaki; T. Ryoukai; M. Hasegawa; K. Hanada; K. N. Sato; K. Nakamura; M. Sakamoto; H. Idei; T. Yoshinaga; S. Kawasaki; H. Nakashima; A. Higashijima

2008-01-01T23:59:59.000Z

368

A Multimedia Tutorial for Charged-Particle Beam Dynamics. Final report  

SciTech Connect

In September 1995 WhistleSoft, Inc., began developing a computer-based multimedia tutorial for charged-particle beam dynamics under Phase II of a Small Business Innovative Research grant from the U.S. Department of Energy. In Phase I of this project (see its Final Report) we had developed several prototype multimedia modules using an authoring system on NeXTStep computers. Such a platform was never our intended target, and when we began Phase II we decided to make the change immediately to develop our tutorial modules for the Windows and Macintosh microcomputer market. This Report details our progress and accomplishments. It also gives a flavor of the look and feel of the presently available and upcoming modules.

Silbar, Richard R.

1999-07-26T23:59:59.000Z

369

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

DOE Patents (OSTI)

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.

Lasche, G.P.

1983-09-29T23:59:59.000Z

370

Physics of neutralization of intense high-energy ion beam pulses by electronsa...  

E-Print Network (OSTI)

Physics of neutralization of intense high-energy ion beam pulses by electronsa... I. D. Kaganovich beams,13 the physics of solar flares,14 high-intensity high- energy particle beam propagation Neutralization and focusing of intense charged particle beam pulses by electrons form the basis for a wide range

Kaganovich, Igor

371

On the fully nonlinear acoustic waves in a plasma with positrons beam impact and superthermal electrons  

SciTech Connect

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.

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

372

SIMPLIFIED CHARGED PARTICLE BEAM TRANSPORT MODELING USING COMMONLY AVAILABLE COMMERCIAL SOFTWARE  

SciTech Connect

Particle beam modeling in accelerators has been the focus of considerable effort since the 1950s. Many generations of tools have resulted from this process, each leveraging both prior experience and increases in computer power. However, continuing innovation in accelerator technology results in systems that are not well described by existing tools, so the software development process is on-going. We discuss a novel response to this situation, which was encountered when Jefferson Lab began operation of its energy-recovering linacs. These machines were not readily described with legacy soft-ware; therefore a model was built using Microsoft Excel. This interactive simulation can query data from the accelerator, use it to compute machine parameters, analyze difference orbit data, and evaluate beam properties. It can also derive new accelerator tunings and rapidly evaluate the impact of changes in machine configuration. As it is spreadsheet-based, it can be easily user-modified in response to changing requirements. Examples for the JLab IR Upgrade FEL are presented.

D. Douglas; K. Beard; J. Eldred; P. Evtushenko; A. Jenkins; W. Moore; L. Osborne; D. Sexton; C. Tennant

2007-06-18T23:59:59.000Z

373

Artificial intelligence research in particle accelerator control systems for beam line tuning  

SciTech Connect

Tuning particle accelerators is time consuming and expensive, with a number of inherently non-linear interactions between system components. Conventional control methods have not been successful in this domain and the result is constant and expensive monitoring of the systems by human operators. This is particularly true for the start-up and conditioning phase after a maintenance period or an unexpected fault. In turn, this often requires a step-by-step restart of the accelerator. Surprisingly few attempts have been made to apply intelligent accelerator control techniques to help with beam tuning, fault detection, and fault recovery problems. The reason for that might be that accelerator facilities are rare and difficult to understand systems that require detailed expert knowledge about the underlying physics as well as months if not years of experience to understand the relationship between individual components, particularly if they are geographically disjoint. This paper will give an overview about the research effort in the accelerator community that has been dedicated to the use of artificial intelligence methods for accelerator beam line tuning.

Pieck, Martin [Los Alamos National Laboratory

2008-01-01T23:59:59.000Z

374

Beam quality corrections for parallel-plate ion chambers in electron reference dosimetry  

Science Journals Connector (OSTI)

Current dosimetry protocols (AAPM, IAEA, IPEM, DIN) recommend parallel-plate ionization chambers for dose measurements in clinical electron beams. This study presents detailed Monte Carlo simulations of beam quality correction factors for four different types of parallel-plate chambers: NACP-02, Markus, Advanced Markus and Roos. These chambers differ in constructive details which should have notable impact on the resulting perturbation corrections, hence on the beam quality corrections. The results reveal deviations to the recommended beam quality corrections given in the IAEA TRS-398 protocol in the range of 0%–2% depending on energy and chamber type. For well-guarded chambers, these deviations could be traced back to a non-unity and energy-dependent wall perturbation correction. In the case of the guardless Markus chamber, a nearly energy-independent beam quality correction is resulting as the effects of wall and cavity perturbation compensate each other. For this chamber, the deviations to the recommended values are the largest and may exceed 2%. From calculations of type-B uncertainties including effects due to uncertainties of the underlying cross-sectional data as well as uncertainties due to the chamber material composition and chamber geometry, the overall uncertainty of calculated beam quality correction factors was estimated to be

K Zink; J Wulff

2012-01-01T23:59:59.000Z

375

Compact disposal of high-energy electron beams using passive or laser-driven plasma decelerating stage  

SciTech Connect

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.

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

376

High-power radio frequency pulse generation and extration based on wakefield excited by an intense charged particle beam in dielectric-loaded waveguides.  

SciTech Connect

Power extraction using a dielectric-loaded (DL) waveguide is a way to generate high-power radio frequency (RF) waves for future particle accelerators, especially for two-beam-acceleration. In a two-beam-acceleration scheme, a low-energy, high-current particle beam is passed through a deceleration section of waveguide (decelerator), where the power from the beam is partially transferred to trailing electromagnetic waves (wakefields); then with a properly designed RF output coupler, the power generated in the decelerator is extracted to an output waveguide, where finally the power can be transmitted and used to accelerate another usually high-energy low-current beam. The decelerator, together with the RF output coupler, is called a power extractor. At Argonne Wakefield Accelerator (AWA), we designed a 7.8GHz power extractor with a circular DL waveguide and tested it with single electron bunches and bunch trains. The output RF frequency (7.8GHz) is the sixth harmonic of the operational frequency (1.3GHz) of the electron gun and the linac at AWA. In single bunch excitation, a 1.7ns RF pulse with 30MW of power was generated by a single 66nC electron bunch passing through the decelerator. In subsequent experiments, by employing different splitting-recombining optics for the photoinjector laser, electron bunch trains were generated and thus longer RF pulses could be successfully generated and extracted. In 16-bunch experiments, 10ns and 22ns RF pulses have been generated and extracted; and in 4-bunch experiments, the maximum power generated was 44MW with 40MW extracted. A 26GHz DL power extractor has also been designed to test this technique in the millimeter-wave range. A power level of 148MW is expected to be generated by a bunch train with a bunch spacing of 769ps and bunch charges of 20nC each. The arrangement for the experiment is illustrated in a diagram. Higher-order-mode (HOM) power extraction has also been explored in a dual-frequency design. By using a bunch train with a bunch spacing of 769ps and bunch charges of 50nC each, 90.4MW and 8.68MW of extracted power levels are expected to be reached at 20.8GHz and 35.1GHz, respectively. In order to improve efficiency in HOM power extraction, a novel technique has been proposed to suppress unintended modes.

Gao, F.; High Energy Physics; Illinois Inst. of Tech

2009-07-24T23:59:59.000Z

377

Monte Carlo calculations for reference dosimetry of electron beams with the PTW Roos and NE2571 ion chambers  

SciTech Connect

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.

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

378

Technical Challenges and Scientific Payoffs of Muon Beam Accelerators for Particle Physics  

E-Print Network (OSTI)

of 2006 European Particle Accelerator Conf. , Edinburgh,Proc. 1992 European Particle Accelerator Conference, Berlin,in Proc. 2007 Particle Accelerator Conf. , Albuquerque, June

Zisman, Michael S.

2008-01-01T23:59:59.000Z

379

Application of the Eigen-Emittance Concept to Design Ultra-Bright Electron Beams  

SciTech Connect

Using correlations at the cathode to tailor a beam's eigen-emittances is a recent concept made useful by the symplectic nature of Hamiltonian systems such as beams in accelerators. While introducing correlations does not change the overall 6-dimensional phase space volume, it can change the partitioning of this volume into the longitudinal and two transverse emittances, which become these eigen-emittances if all the initial correlations are unwound and removed. In principle, this technique can be used to generate beams with highly asymmetric emittances, such as those needed for the next generation of very hard X-ray free-electron lasers. This approach is based on linear correlations, and its applicability will be limited by the magnitude of nonlinear effects in photoinjectors which will lead to mixing in phase space that cannot be unwound downstream. Here, we review the eigen-emittance concept and present a linear eigen-emittance design leading to a highly partitioned, and transverse ultra-bright, electron beam. We also present numerical tools to examine the evolution of the eigen-emittances in realistic accelerator structures and results indicating how much partitioning is practical.

Duffy, Leanne D. [Los Alamos National Laboratory; Bishofberger, Kip A. [Los Alamos National Laboratory; Carlsten, Bruce E. [Los Alamos National Laboratory; Dragt, Alex [U. Maryland; Russell, Steven J. [Los Alamos National Laboratory; Ryne, Robert D. [LBNL; Yampolsky, Nikolai A. [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

380

The acceleration of electrons at perpendicular shocks and its implication for solar energetic particle events  

SciTech Connect

We present a study of the acceleration of electrons at a perpendicular shock that propagates through a turbulent magnetic field. The energization process of electrons is investigated by utilizing a combination of hybrid (kinetic ions and fluid electron) simulations and test-particle electron simulations. In this method, the motions of the test-particle electrons are numerically integrated in the time-dependent electric and magnetic fields generated by two-dimensional hybrid simulations. We show that large-scale magnetic fluctuations effect electrons in a number of ways and lead to efficient and rapid energization at the shock front. Since the electrons mainly follow along magnetic lines of force, the large-scale braiding of field lines in space allows the fast-moving electrons to interact with the shock front and get accelerated multiple times. Ripples in the shock front occurring at various scales will also contribute to the acceleration by mirroring the electrons. Our calculation shows that this process favors electron acceleration at perpendicular shocks. The acceleration efficiency is critically dependent on the turbulence amplitude and coherence length. We also discuss the implication of this study for solar energetic particles (SEPs) by comparing the acceleration of electrons with that of protons. Their correlation indicates that perpendicular shocks play an important role in SEP events.

Guo Fan; Giacalone, Joe [Department of Planetary Sciences, University of Arizona, Tucson, AZ 85721 (United States)

2012-11-20T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
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381

Characterization of U-6Nb ingots produced via the electron beam cold hearth refining process  

SciTech Connect

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.

McKoon, R.H.

1997-11-14T23:59:59.000Z

382

Note: Production of a mercury beam with an electron cyclotron resonance ion source  

SciTech Connect

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.

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

383

Electron beam method and apparatus for obtaining uniform discharges in electrically pumped gas lasers  

DOE Patents (OSTI)

A method and apparatus for obtaining uniform, high-energy, large-volume electrical discharges in the lasing medium of a gas laser whereby a high-energy electron beam is used as an external ionization source to ionize substantially the entire volume of the lasing medium which is then readily pumped by means of an applied potential less than the breakdown voltage of the medium. The method and apparatus are particularly useful in CO.sub.2 laser systems.

Fenstermacher, Charles A. (Los Alamos, NM); Boyer, Keith (Los Alamos, NM)

1986-01-01T23:59:59.000Z

384

Modeling and performance of a single-electron-beam two-FEL system  

Science Journals Connector (OSTI)

The use of a single electron beam to power a master oscillator and power amplifier was demonstrated in the Rocketdyne/Stanford experiment. This article concentrates on the performance of the downstream element under the assumption of higher performance upstream elements such as might be possible for the high-brightness systems being developed in the Los Alamos and Rocketdyne/Duke programs. The modeling covers the performance of the initial high-extraction efficiency system, the filtering, transport, and refocusing of electrons into a second wiggler, and the performance of the second system. The Rocketdyne 3D simulation code FELOPT was used in the FEL calculations.

Ralph A. Cover

1991-01-01T23:59:59.000Z

385

Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering  

SciTech Connect

We have measured the beam-normal single-spin asymmetry in elastic scattering of transversely polarized 3 GeV electrons from unpolarized protons at Q{sup 2}=0.15, 0.25 (GeV/c){sup 2}. The results are inconsistent with calculations solely using the elastic nucleon intermediate state and generally agree with calculations with significant inelastic hadronic intermediate state contributions. A{sub n} provides a direct probe of the imaginary component of the 2{gamma} exchange amplitude, the complete description of which is important in the interpretation of data from precision electron-scattering experiments.

Armstrong, D. S.; Averett, T.; Bailey, S. L.; Finn, J. M.; Griffioen, K. A.; Moffit, B.; Phillips, S. K.; Secrest, J.; Sulkosky, V. [Department of Physics, College of William and Mary, Williamsburg, Virginia 23187 (United States); Arvieux, J.; Bimbot, L.; Guler, H.; Lenoble, J.; Marchand, D.; Morlet, M.; Ong, S.; Van de Wiele, J. [Institut de Physique Nucleaire d'Orsay, CNRS/IN2P3, Universite Paris Sud, Orsay (France); Asaturyan, R.; Mkrtchyan, H.; Stepanyan, S. [Yerevan Physics Institute, Yerevan 375036 (Armenia)] (and others)

2007-08-31T23:59:59.000Z

386

A Spin-Light Polarimeter for Multi-GeV Longitudinally Polarized Electron Beams  

SciTech Connect

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.

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

387

Development of Advanced Beam Halo Diagnostics at the Jefferson Lab Free-Electron-Laser Facility  

SciTech Connect

High average current and high brightness electron beams are needed for many applications. At the Jefferson Lab FEL facility, the search for dark matter with the FEL laser beam has produced some interesting results, and a second very promising experiment called ?DarkLight?, using the JLab Energy-recovery-linac (ERL) machine has been put forward. Although the required beam current has been achieved on this machine, one key challenge is the management of beam halo. At the University of Md. (UMD) we have demonstrated a high dynamic range halo measurement method using a digital micro-mirror array device (DMD). A similar system has been established at the JLab FEL facility as a joint effort by UMD and JLab to measure the beam halo on the high current ERL machine. Preliminary experiments to characterize the halo were performed on the new UV FEL. In this paper, the limitations of the present system will be analyzed and a discussion of other approaches (such as an optimized coronagraph) for further extending the dynamic range will be presented. We will also discuss the possibility of performing both longitudinal and transverse (3D) halo measurements together on a single system.

Shukui Zhang, Stephen Benson, Dave Douglas, Frederick Wilson, Hao Zhang, Anatoly Shkvarunets, Ralph Fiorito

2011-03-01T23:59:59.000Z

388

Beam-Gas  

NLE Websites -- All DOE Office Websites (Extended Search)

Gas Gas and Thermal Photon Scattering in the NLC Main Linac as a Source of Beam Halo P. Tenenbaum LCC-Note-0051 12-JAN-2001 Abstract Scattering of primary beam electrons off of residual gas molecules or blackbody radiation photons in the NLC main linac has been identified as a potential source of beam haloes which must be collimated in the beam delivery system. We consider the contributions from four scat- tering mechanisms: inelastic thermal-photon scattering, elastic beam-gas (Coulomb) scattering inelastic beam-gas (Bremsstrahlung) scattering, and atomic-electron scattering. In each case we develop the formalism necessary to estimate the backgrounds generated in the main linac, and determine the expected number of off-energy or large-amplitude particles from each process, assuming a main linac injection energy of 8 GeV and extraction energy of 500 GeV. 1 Introduction The

389

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

SciTech Connect

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.

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

390

Target design optimization for an electron accelerator driven subcritical facility with circular and square beam profiles.  

SciTech Connect

A subcritical facility driven by an electron accelerator is planned at the Kharkov Institute of Physics and Technology (KIPT) in Ukraine for medical isotope production, materials research, training, and education. The conceptual design of the facility is being pursued through collaborations between ANL and KIPT. As part of the design effort, the high-fidelity analyses of various target options are performed with formulations to reflect the realistic configuration and the three dimensional geometry of each design. This report summarizes the results of target design optimization studies for electron beams with two different beam profiles. The target design optimization is performed via the sequential neutronic, thermal-hydraulic, and structural analyses for a comprehensive assessment of each configuration. First, a target CAD model is developed with proper emphasis on manufacturability to provide a basis for separate but consistent models for subsequent neutronic, thermal-hydraulic, and structural analyses. The optimizations are pursued for maximizing the neutron yield, streamlining the flow field to avoid hotspots, and minimizing the thermal stresses to increase the durability. In addition to general geometric modifications, the inlet/outlet channel configurations, target plate partitioning schemes, flow manipulations and rates, electron beam diameter/width options, and cladding material choices are included in the design optimizations. The electron beam interactions with the target assembly and the neutronic response of the subcritical facility are evaluated using the MCNPX code. the results for the electron beam energy deposition, neutron generation, and utilization in the subcritical pile are then used to characterize the axisymmetric heat generation profiles in the target assembly with explicit simulations of the beam tube, the coolant, the clad, and the target materials. Both tungsten and uranium are considered as target materials. Neutron spectra from tungsten and uranium are very similar allowing the use of either material in the subcritical assembly without changing its characteristics. However, the uranium target has a higher neutron yield, which increases the neutron flux of the subcritical assembly. Based on the considered dimensions and heat generation profiles, the commercial CFD software Star-CD is used for the thermal-hydraulic analysis of each target design to satisfy a set of thermal criteria, the most limiting of which being to maintain the water temperature 50 below the boiling point. It is found that the turbulence in the inlet channels dissipates quickly in narrow gaps between the target plates and, as a result, the heat transfer is limited by the laminar flow conditions. On average, 3-D CFD analyses of target assemblies agree well with 1-D calculations using RELAP (performed by KIPT). However, the recirculation and stagnation zones predicted with the CFD models prove the importance of a 3-D analysis to avoid the resulting hotspots. The calculated temperatures are subsequently used for the structural analysis of each target configuration to satisfy the other engineering design requirements. The thermo-structural calculations are performed mostly with NASTRAN and the results occasionally compared with the results from MARC. Both, NASTRAN and MARC are commercially available structural-mechanics analysis software. Although, a significant thermal gradient forms in target elements along the beam direction, the high thermal stresses are generally observed peripherally around the edge of thin target disks/plates. Due to its high thermal conductivity, temperatures and thermal stresses in tungsten target are estimated to be significantly lower than in uranium target. The deformations of the target disks/plates are found to be insignificant, which eliminate concerns for flow blockages in narrow coolant channels. Consistent with the specifications of the KIPT accelerator to be used in this facility, the electron beam power is 100-kW with electron energy in the range of 100 to 200 MeV. As expected, the 100 MeV el

Gohar, M. Y. A; Sofu, T.; Zhong, Z.; Belch, H.; Naberezhnev, D.; Nuclear Engineering Division

2008-10-30T23:59:59.000Z

391

A Hybrid Laser-driven E-beam Injector Using Photo-cathode Electron Gun and superconducting Cavity*  

E-Print Network (OSTI)

A Hybrid Laser-driven E-beam Injector Using Photo-cathode Electron Gun and superconducting Cavity, Beijing 100871, China * Work supported by NNSF of China Abstract A laser-driven photo-cathode electron gun constructed and tested. As the next step, a hybrid photo-injector, using a DC laser-driven electron gun

Geng, Rong-Li

392

Electron Source in Photoinduced Hydrogen Production on Pt-supported TiO2 Particles  

Science Journals Connector (OSTI)

Electron Source in Photoinduced Hydrogen Production on Pt-supported TiO2 Particles ... After recovering the TiO2/Pt particles used in the long-term reaction, they were reused in a photocatalytic H+ reduction by adding methanol as an electron donor, but no H2 production was observed showing that the TiO2/Pt particles have lost their photocatalytic activity after the long-term reaction. ... A 100 W high-pressure Hg lamp was used as a light source. ...

Toshiyuki Abe; Eiji Suzuki; Kentaro Nagoshi; Kohichi Miyashita; Masao Kaneko

1999-02-04T23:59:59.000Z

393

Conceptual Design of a 50--100 MW Electron Beam Accelerator System for the National Hypersonic Wind Tunnel Program  

SciTech Connect

The National Hypersonic Wind Tunnel program requires an unprecedented electron beam source capable of 1--2 MeV at a beam power level of 50--100 MW. Direct-current electron accelerator technology can readily generate high average power beams to approximately 5 MeV at output efficiencies greater than 90%. However, due to the nature of research and industrial applications, there has never been a requirement for a single module with an output power exceeding approximately 500 kW. Although a 50--100 MW module is a two-order extrapolation from demonstrated power levels, the scaling of accelerator components appears reasonable. This paper presents an evaluation of component and system issues involved in the design of a 50--100 MW electron beam accelerator system with precision beam transport into a high pressure flowing air environment.

SCHNEIDER,LARRY X.

2000-06-01T23:59:59.000Z

394

Cross sections for electron capture by neutral and charged particles in collisions with He  

Science Journals Connector (OSTI)

Experimental and theoretical cross sections for electron capture by neutral and charged particles in collisions with He atoms are tabulated and displayed in graphical form as a function of the energy of the incident projectile and according to the projectile charge state and, to the extent possible, the final electronic state. Literature from 1955 to March 1986 has been covered.

W.K. Wu; B.A. Huber; K. Wiesemann

1988-01-01T23:59:59.000Z

395

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

SciTech Connect

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.

Knapp, D.

1994-11-02T23:59:59.000Z

396

Quasi-monoenergetic Electron Beams from Laser-plasma Acceleration by Ionization-induced Injection in Low- density Pure Nitrogen  

E-Print Network (OSTI)

We report a laser wakefield acceleration of electron beams up to 130 MeV from laser-driven 4-mm long nitrogen gas jet. By using a moderate laser intensity (3.5*10^18 W.cm^(-2) ) and relatively low plasma densities (0.8*10^18 cm^(-3) to 2.7*10^18 cm^(-3)) we have achieved a stable regime for laser propagation and consequently a stable generation of electron beams. We experimentally studied the dependence of the drive laser energy on the laser-plasma channel and electron beam parameters. The quality of the generated electron beams is discussed within the framework of the ionization-induced injection mechanism.

Tao, Mengze; Li, Song; Mirzaie, Mohammad; Chen, Liming; He, Fei; Cheng, Ya; Zhang, Jie

2014-01-01T23:59:59.000Z

397

Sub-10-nm half-pitch electron-beam lithography by using poly(methyl methacrylate) as a negative resist  

E-Print Network (OSTI)

Developing high-resolution resists and processes for electron-beam lithography is of great importance for high-density magnetic storage, integrated circuits, and nanoelectronic and nanophotonic devices. Until now, hydrogen ...

Berggren, Karl K.

398

Enhanced thermotolerance and ethanol tolerance in Saccharomyces cerevisiae mutated by high-energy pulse electron beam and protoplast fusion  

Science Journals Connector (OSTI)

To increase thermotolerance and ethanol tolerance in Saccharomyces cerevisiae strain YZ1, the strategies of high-energy pulse electron beam (HEPE) and three ... characteristics of resistant to high-temperature, h...

Min Zhang; Yu Xiao; Rongrong Zhu; Qin Zhang…

2012-11-01T23:59:59.000Z

399

Simulation and design of an electron beam ion source charge breeder for the californium rare isotope breeder upgrade  

Science Journals Connector (OSTI)

An electron beam ion source (EBIS) will be constructed and used to charge breed ions from the californium rare isotope breeder upgrade (CARIBU) for postacceleration into the Argonne tandem linear accelerator system (ATLAS). Simulations of the EBIS charge breeder performance and the related ion transport systems are reported. Propagation of the electron beam through the EBIS was verified, and the anticipated incident power density within the electron collector was identified. The full normalized acceptance of the charge breeder with a 2 A electron beam, 0.024???mm?mrad for nominal operating parameters, was determined by simulating ion injection into the EBIS. The optics of the ion transport lines were carefully optimized to achieve well-matched ion injection, to minimize emittance growth of the injected and extracted ion beams, and to enable adequate testing of the charge bred ions prior to installation in ATLAS.

Clayton Dickerson; Brahim Mustapha; Alexander Pikin; Sergey Kondrashev; Peter Ostroumov; Anthony Levand; Rick Fischer

2013-02-15T23:59:59.000Z

400

THE EFFECTS OF ELECTRON BEAM IRRADIATION AND SANITIZERS IN THE REDUCTION OF PATHOGENS AND ATTACHMENT PREVENTION ON SPINACH  

E-Print Network (OSTI)

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...

Neal, Jack A.

2010-07-14T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


401

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

E-Print Network (OSTI)

Laser-Energy Transfer and Enhancement of Plasma Waves and Electron Beams by Interfering High-Intensity) The effects of interference due to crossed laser beams were studied experimentally in the high- intensity regime. Two ultrashort (400 fs), high-intensity (4 1017 and 1:6 1018 W=cm2) and 1 m wavelength laser

Umstadter, Donald

402

Enhanced production of low energy electrons by alpha particle impact  

Science Journals Connector (OSTI)

...2.5 MV Van-de-Graaff accelerator at the Institut fur Kernphysik...electronic decay driven by nuclear motion . Phys Rev Lett 105 : 173401...Waals Clusters and Impact of Nuclear Motion . Phys Rev Lett 85 : 4490...of Ne 2 by high-resolution vacuum ultraviolet laser spectroscopy...

Hong-Keun Kim; Jasmin Titze; Markus Schöffler; Florian Trinter; Markus Waitz; Jörg Voigtsberger; Hendrik Sann; Moritz Meckel; Christian Stuck; Ute Lenz; Matthias Odenweller; Nadine Neumann; Sven Schössler; Klaus Ullmann-Pfleger; Birte Ulrich; Rui Costa Fraga; Nikos Petridis; Daniel Metz; Annika Jung; Robert Grisenti; Achim Czasch; Ottmar Jagutzki; Lothar Schmidt; Till Jahnke; Horst Schmidt-Böcking; Reinhard Dörner

2011-01-01T23:59:59.000Z

403

Development of diagnostic and manipulation systems for space-charge dominated electron beams and confined electron plasmas in ELTRAP  

SciTech Connect

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.

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

404

Bistable solutions for the electron energy distribution function in electron swarms in xenon via Boltzmann equation analysis and particle simulations  

E-Print Network (OSTI)

At low reduced electric fields the electron energy distribution function in heavy noble gases can take two distinct shapes. This bistability effect - in which electron-electron (Coulomb) collisions play an essential role - is analyzed here with a Boltzmann equation approach and with a first principles particle simulation method. The latter is based on a combination of a molecular dynamics technique that accounts for the many-body interaction within the electron gas and a Monte Carlo treatment of the collisions between electrons and the background gas atoms. The good agreement found between the results of the two techniques confirms the existence of the two different stable solutions for the EEDF under swarm conditions at low electric fields.

Dyatko, Nikolay

2015-01-01T23:59:59.000Z

405

E-Print Network 3.0 - accelerator electron beam Sample Search...  

NLE Websites -- All DOE Office Websites (Extended Search)

Summary: radiation facilities for biology and material sciences. Beam physics--study of beams in accelerators... high-brightness x-ray beams in synchrotron radiation facilities and...

406

Optimizing the CEBAF Injector for Beam Operation with a Higher Voltage Electron Gun  

SciTech Connect

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.

F.E. Hannon, A.S. Hofler, R. Kazimi

2011-03-01T23:59:59.000Z

407

Optimization of spin polarization in the HERA electron ring using beam-based alignment procedures  

SciTech Connect

The maximum degree of electron spin polarization in a real storage ring is mainly limited by the tilt of the equilibrium polarization direction {ital n}{searrow}{sub 0} with respect to the direction of the main bending fields. The tilt is mainly caused by random vertical closed orbit kicks introduced by nonzero vertical offsets inside the quadrupoles. Methods for minimizing the average tilt of {ital n}{searrow}{sub 0} are discussed and a correction algorithm is introduced which makes use of the known correlations between transverse offsets of quadrupoles and adjacent beam position monitors. The correlation can be established by a beam-based alignment technique. The results of first measurements are presented. {copyright} {ital 1995 American Institute of Physics.}

Boege, M.; Brinkmann, R. [Deutsches Elektronen-Synchroton DESY, Notkestr. 85, D-22603 Hamburg (Germany)

1995-09-01T23:59:59.000Z

408

Measurement of electron beam polarization from unstrained GaAs via two-photon photoemission  

SciTech Connect

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.

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

409

Beam energy distribution influences on density modulation efficiency in seeded free-electron lasers  

E-Print Network (OSTI)

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...

Wang, Guanglei; Deng, Haixiao; Zhang, Weiqing; Wu, Guorong; Dai, Dongxu; Wang, Dong; Zhao, Zhentang; Yang, Xueming

2015-01-01T23:59:59.000Z

410

Electron beam irradiation of dimethyl-(acetylacetonate) gold(III) adsorbed onto solid substrates  

SciTech Connect

Electron beam induced deposition of organometallic precursors has emerged as an effective and versatile method for creating two-dimensional and three-dimensional metal-containing nanostructures. However, to improve the properties and optimize the chemical composition of nanostructures deposited in this way, the electron stimulated decomposition of the organometallic precursors must be better understood. To address this issue, we have employed an ultrahigh vacuum-surface science approach to study the electron induced reactions of dimethyl-(acetylacetonate) gold(III) [Au{sup III}(acac)Me{sub 2}] adsorbed onto solid substrates. Using thin molecular films adsorbed onto cooled substrates, surface reactions, reaction kinetics, and gas phase products were studied in the incident energy regime between 40 and 1500 eV using a combination of x-ray photoelectron spectroscopy (XPS), reflection absorption infrared spectroscopy (RAIRS), and mass spectrometry (MS). XPS and RAIRS data indicate that electron irradiation of Au{sup III}(acac)Me{sub 2} is accompanied by the reduction in Au{sup III} to a metallic Au{sup 0} species embedded in a dehydrogenated carbon matrix, while MS reveals the concomitant evolution of methane, ethane, carbon monoxide, and hydrogen. The electron stimulated decomposition of Au{sup III}(acac)Me{sub 2} is first-order with respect to the surface coverage of the organometallic precursor, and exhibits a rate constant that is proportional to the electron flux. At an incident electron energy of 520 eV, the total reaction cross section was {approx_equal}3.6x10{sup -16} cm{sup 2}. As a function of the incident electron energy, the maximum deposition yield was observed at {approx_equal}175 eV. The structure of discrete Au-containing deposits formed at room temperature by rastering an electron beam across a highly ordered pyrolytic graphite substrate in the presence of a constant partial pressure of Au{sup III}(acac)Me{sub 2} was also investigated by atomic force microscopy.

Wnuk, Joshua D.; Gorham, Justin M.; Rosenberg, Samantha G.; Fairbrother, D. Howard [Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Dorp, Willem F. van [Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers, State University of New Jersey, Piscataway, New Jersey 08854-8019 (United States); Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628CJ Delft (Netherlands); Madey, Theodore E. [Department of Physics and Astronomy and Laboratory for Surface Modification, Rutgers, State University of New Jersey, Piscataway, New Jersey 08854-8019 (United States); Hagen, Cornelis W. [Faculty of Applied Sciences, Delft University of Technology, Lorentzweg 1, 2628CJ Delft (Netherlands)

2010-03-15T23:59:59.000Z

411

Fast ignition: Dependence of the ignition energy on source and target parameters for particle-in-cell-modelled energy and angular distributions of the fast electrons  

SciTech Connect

The energy and angular distributions of the fast electrons predicted by particle-in-cell (PIC) simulations differ from those historically assumed in ignition designs of the fast ignition scheme. Using a particular 3D PIC calculation, we show how the ignition energy varies as a function of source-fuel distance, source size, and density of the pre-compressed fuel. The large divergence of the electron beam implies that the ignition energy scales with density more weakly than the ?{sup ?2} scaling for an idealized beam [S. Atzeni, Phys. Plasmas 6, 3316 (1999)], for any realistic source that is at some distance from the dense deuterium-tritium fuel. Due to the strong dependence of ignition energy with source-fuel distance, the use of magnetic or electric fields seems essential for the purpose of decreasing the ignition energy.

Bellei, C.; Divol, L.; Kemp, A. J.; Key, M. H.; Larson, D. J.; Strozzi, D. J.; Marinak, M. M.; Tabak, M.; Patel, P. K. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550 (United States)

2013-05-15T23:59:59.000Z

412

Electron muon identification by atmospheric shower and electron beam in a new concept of an EAS detector  

E-Print Network (OSTI)

We present results demonstrating the time resolution and $\\mu$/e separation capabilities with a new concept of an EAS detector capable for measurements of cosmic rays arriving with large zenith angles. This kind of detector has been designed to be a part of a large area (several square kilometers) surface array designed to measure Ultra High Energy (10-200 PeV) $\\tau$ neutrinos using the Earth-skimming technique. A criteria to identify electron-gammas is also shown and the particle identification capability is tested by measurements in coincidence with the KASKADE-GRANDE experiment in Karlsruhe, Germany.

Iori, M; Yilmaz, A; Ferrarotto, F; Russ, J

2015-01-01T23:59:59.000Z

413

Beam-Beam Interaction Simulations with Guinea Pig  

NLE Websites -- All DOE Office Websites (Extended Search)

5 5 SLAC-TN-03-070 September 2003 Beam-Beam Interaction Simulations with Guinea Pig C. Sramek, T. O. Raubenheimer, A. Seryi, M. Woods, J. Yu Stanford Linear Accelerator Center Stanford University Stanford, CA Abstract: At the interaction point of a particle accelerator, various phenomena occur that are known as beam-beam effects. Incident bunches of electrons (or positrons) experience strong electromagnetic fields from the opposing bunches, which leads to electron deflection, beamstrahlung and the creation of electron/positron pairs and hadrons due to two-photon exchange. In addition, the beams experience a "pinch effect" which focuses each beam and results in either a reduction or expansion of their vertical size. Finally, if a

414

Single-walled carbon nanotubes and nanocrystalline graphene reduce beam-induced movements in high-resolution electron cryo-microscopy of ice-embedded biological samples  

E-Print Network (OSTI)

For single particle electron cryo-microscopy (cryoEM), contrast loss due to beam-induced charging and specimen movement is a serious problem, as the thin films of vitreous ice spanning the holes of a holey carbon film are particularly susceptible to beam-induced movement. We demonstrate that the problem is at least partially solved by carbon nanotechnology. Doping ice-embedded samples with single-walled carbon nanotubes (SWNT) in aqueous suspension or adding nanocrystalline graphene supports, obtained by thermal conversion of cross-linked self-assembled biphenyl precursors, significantly reduces contrast loss in high-resolution cryoEM due to the excellent electrical and mechanical properties of SWNTs and graphene.

Daniel Rhinow; Nils-Eike Weber; Andrey Turchanin; Armin Gölzhäuser; Werner Kühlbrandt

2011-10-06T23:59:59.000Z

415

Fundamental electron-precursor-solid interactions derived from time dependent electron beam induced deposition simulations and experiments  

SciTech Connect

Unknown parameters critical to understanding the electron-precursor substrate interactions during electron beam induced deposition (EBID) have long limited our ability to fully control this nanoscale, directed assembly method. We report here values for the fundamental interaction parameters of D, the precursor surface diffusion coefficient, delta, the sticking probability and tau, the mean surface residence time which are critical parameters for understanding the assembly of EBID deposits. Values of D=6.4um2s-1, delta=0.0250 and tau=3.2ms were determined for a commonly used precursor molecule tungsten hexacarbonyl W(CO)6. Space and time predictions of the adsorbed precursor coverage C(r,t) were solved by an explicit finite differencing numerical scheme. Evolving nanopillar surface morphology was derived from solutions of C(r,t) considering electron induced dissociation as the critical depletion term. This made it possible to infer the space and time dependent precursor coverage both on, and around nanopillar structures to better understand local precursor dynamics during mass transport limited (MTL) and reaction rate limited (RRL) EBID.

Fowlkes, Jason Davidson [ORNL; Rack, Philip D [ORNL

2010-01-01T23:59:59.000Z

416

Rare-earth neutral metal injection into an electron beam ion trap plasma  

SciTech Connect

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.

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

417

2D electron density profile measurement in tokamak by laser-accelerated ion-beam probe  

SciTech Connect

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.

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

418

IMPEDANCE OF ELECTRON BEAM VACUUM CHAMBERS FOR THE NSLS-II STORAGE RING.  

SciTech Connect

In this paper we discuss computation of the coupling impedance of the vacuum chambers for the NSLS-II storage ring using the electromagnetic simulator GdfidL [1]. The impedance of the vacuum chambers depends on the geometric dimensions of the cross-section and height of the slot in the chamber wall. Of particular concern is the complex geometry of the infrared extraction chambers to be installed in special large-gap dipole magnets. In this case, wakefields are generated due to tapered transitions and large vertical-aperture ports with mirrors near the electron beam.

BLEDNYKH,A.; KRINSKY, S.

2007-06-25T23:59:59.000Z

419

Electron-beam patterning of polymer electrolyte films to make multiple nanoscale gates for nanowire transistors  

E-Print Network (OSTI)

We report an electron-beam based method for the nanoscale patterning of the poly(ethylene oxide)/LiClO$_{4}$ polymer electrolyte. We use the patterned polymer electrolyte as a high capacitance gate dielectric in single nanowire transistors and obtain subthreshold swings comparable to conventional metal/oxide wrap-gated nanowire transistors. Patterning eliminates gate/contact overlap which reduces parasitic effects and enables multiple, independently controllable gates. The method's simplicity broadens the scope for using polymer electrolyte gating in studies of nanowires and other nanoscale devices.

D. J. Carrad; A. M. Burke; R. W. Lyttleton; H. J. Joyce; H. H. Tan; C. Jagadish; K. Storm; H. Linke; L. Samuelson; A. P. Micolich

2014-04-08T23:59:59.000Z

420

Polyatomic-buffered pulsed DF/HF laser using electron-beam or photolysis initiation  

SciTech Connect

The initial performance of pulsed DF/HF chain lasers is presented in which the effect of polyatomic diluents on laser behavior is systematically explored. Laser energy, pulse length, and spectral output were investigated as functions of diluent gas (NF3, SF6, CF4), total mixture pressure, the partial pressure of fuel and oxidizer, O/sub 2/ concentration, and strength of initiation. Magnetically-confined electron beam and photolytically initiated systems are found to yield comparable performance. Results include 65 J/liter-atm DF output at 200 Torr cavity pressure and the ability to suppress long wavelength transitions from the free-running spectrum. 21 references.

Amimoto, S.T.; Gross, R.W.F.; Harper, G.N.; Azevedo, L.S.; Hofland, R. Jr.

1987-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


421

Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion source  

SciTech Connect

The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current ({approx}100 {mu}A) with high charge ({approx}10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline.

Kondo, K.; Okamura, M. [Collider-Accelerator Department, Brookhaven National Laboratory, New York (United States); Yamamoto, T. [Cooperative Major in Nuclear Energy, Waseda University, Tokyo (Japan); Sekine, M. [Department of Nuclear Engineering, Tokyo Institute of Technology, Tokyo (Japan)

2012-02-15T23:59:59.000Z

422

Vibrational excitation induced by electron beam and cosmic rays in normal and superconductive aluminum bars  

E-Print Network (OSTI)

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.

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

423

Laser ion source with solenoid for Brookhaven National Laboratory-electron beam ion source  

SciTech Connect

The electron beam ion source (EBIS) preinjector at Brookhaven National Laboratory (BNL) is a new heavy ion-preinjector for relativistic heavy ion collider (RHIC) and NASA Space Radiation Laboratory (NSRL). Laser ion source (LIS) is a primary ion source provider for the BNL-EBIS. LIS with solenoid at the plasma drift section can realize the low peak current ({approx}100 {micro}A) with high charge ({approx}10 nC) which is the BNL-EBIS requirement. The gap between two solenoids does not cause serious plasma current decay, which helps us to make up the BNL-EBIS beamline.

Kondo K.; Yamamoto, T.; Sekine, M.; Okamura, M.

2012-02-22T23:59:59.000Z

424

6-dimensional Kaluza-Klein Theory for Basic Quantum Particles and Electron-Photon Interaction  

E-Print Network (OSTI)

By extending original Kaluza-Klein theory to 6-dimension, the basic quantum field equations for 0-spin particle, 1-spin particle and 1/2 spin particle with mass >0 are directly derived from 6-dimensional Einstein equations. It shows that the current quantum field equations of basic particles become pure geometry properties under 6-dimension time-space. The field equations of electron and photon can be unified in one 6-dimensional extended Maxwell equation. The equations containing interactions between electron and photon will be derived from Einstein equation under 6-dimension time-space. It shows that the interactions in QED can be considered as the effect of local geometry curvature changing instead of exchange virtual photons.

Xiaodong Chen

2005-01-26T23:59:59.000Z

425

Generation of Initial Kinetic Distributions for Simulation of Long-Pulse Charged Particle Beams with High Space-Charge intensity  

SciTech Connect

Self-consistent Vlasov-Poisson simulations of beams with high space-charge intensity often require specification of initial phase-space distributions that reflect properties of a beam that is well adapted to the transport channel--both in terms of low-order rms (envelope) properties as well as the higher-order phase-space structure. Here, we first review broad classes of kinetic distributions commonly in use as initial Vlasov distributions in simulations of unbunched or weakly bunched beams with intense space-charge fields including: the Kapchinskij-Vladimirskij (KV) equilibrium, continuous-focusing equilibria with specific detailed examples, and various non-equilibrium distributions, such as the semi-Gaussian distribution and distributions formed from specified functions of linear-field Courant-Snyder invariants. Important practical details necessary to specify these distributions in terms of usual accelerator inputs are presented in a unified format. Building on this presentation, a new class of approximate initial kinetic distributions are constructed using transformations that preserve linear-focusing single-particle Courant-Snyder invariants to map initial continuous-focusing equilibrium distributions to a form more appropriate for non-continuous focusing channels. Self-consistent particle-in-cell simulations are employed to show that the approximate initial distributions generated in this manner are better adapted to the focusing channels for beams with high space-charge intensity. This improved capability enables simulation applications that more precisely probe intrinsic stability properties and machine performance.

Lund, Steven M.; Kikuchi, Takashi; Davidson, Ronald C.

2007-04-03T23:59:59.000Z

426

Generation of initial Vlasov distributions for simulation of charged particle beams with high space-charge intensity  

SciTech Connect

Self-consistent Vlasov simulations of beams with high space-charge intensity often require specification of initial phase-space distributions that reflect properties of a beam that is well adapted to the transport channel, both in terms of low-order rms (envelope) properties as well as the higher-order phase-space structure. Here, we first review broad classes of distributions commonly in use as initial Vlasov distributions in simulations of beams with intense space-charge fields including: the Kapchinskij-Vladimirskij (KV) equilibrium, continuous-focusing equilibria with specific detailed examples, and various non-equilibrium distributions, such as the semi-Gaussian distribution and distributions formed from specified functions of linear-field Courant-Snyder invariants. Important practical details necessary to specify these distributions in terms of usual accelerator inputs are presented in a unified format. Building on this presentation, a new class of approximate initial distributions are constructed using transformations that preserve linear-focusing single-particle Courant-Snyder invariants to map initial continuous-focusing equilibrium distributions to a form more appropriate for non-continuous focusing channels. Self-consistent particle-in-cell simulations are employed to show that the approximate initial distributions generated in this manner are better adapted to the focusing channels for beams with high space-charge intensity. This improved capability enables simulation applications that more precisely probe intrinsic stability properties and machine performance.

Lund, S M; Kikuchi, T; Davidson, R C

2007-04-12T23:59:59.000Z

427

Patterned aluminum nanowires produced by electron beam at the surfaces of AlF3 single crystals  

E-Print Network (OSTI)

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

Wang, Zhong L.

428

IonCCD™ for direct position-sensitive charged-particle detection: from electrons and keV ions to hyperthermal biomolecular ions  

SciTech Connect

A novel charged-particle sensitive, pixel based detector array is described and its usage is demonstrated for a variety of applications, from detection of elemental particles (electrons) to hyper-thermal large biomolecular positive and negative ions including keV light atomic and molecular ions. The array detector is a modified light-sensitive charged coupled device (CCD). The IonCCDTM was engineered for direct charged particle detection by replacing the semi-conductor part of the CCD pixel by a conductor1. In contrast with the CCD, where the semi-conductive pixel is responsible for electron-hole pair formation upon photon bombardment, the IonCCD uses a capacitor coupled to the conductive electrode for direct charge integration. The detector can be operated from atmospheric pressure to high vacuum since no high voltages are needed. The IonCCD, presented in this work is an array of 2126 active pixels with 21 um pixel width and 3 um pixel gap. The detection area is 1.5x51mm2 where 1.5 mm and 51 mm are pixel and detector array length, respectively. The result is a one-dimensional position-sensitive detector with 24 um spatial resolution and 88 % pixel area ratio (PAR). In this work we demonstrate the capabilities and the performance of the detector. For the first time we show the direct detection of 250 eV electrons providing linearity response and detection efficiency of the IonCCD as function of electron beam current. Using positive ions from and electron impact source (E-I), we demonstrate that the detection efficiency of the IonCCD is virtually independent of particle energy [250 eV, 1250 eV], particle impact angle [45o, 90o] and particle flux. By combining the IonCCD with a double focusing sector field of Mattauch-Herzog geometry (M-H), we demonstrate fast acquisition of mass spectra in direct air sniffing mode. A first step towards fast in vivo breath analysis is presented. Detection of hyper-thermal biomolecular ions produced using an electrospray ionization source (ESI) is presented. The IonCCD was used as beam profiler to characterize the beam shape and intensity of 15 eV protonated and deprotonated biomolecular ions at the exit of an RF only collisional quadrupole. We present simultaneous detection of 140 eV doubly protonated biomolecular ions when the IonCCD is combined with the M-H analyzer. The latter, demonstrates the possibility of simultaneous separation and micro-array deposition of biological material using a miniature sector field.

Hadjar, Omar; Johnson, Grant E.; Laskin, Julia; Kibelka, Gottfried; Shill, Scott M.; Kuhn, Ken; Cameron, Chad; Kassan, Scott

2011-04-01T23:59:59.000Z

429

One- and two-particle effects in the electronic and optical spectra of barium fluoride  

Science Journals Connector (OSTI)

One- and two-particle effects in the electronic and optical spectra of the fluoride compound BaF2 are determined using density functional theory and a many-body perturbation scheme. A wide energy range has been considered, including the visible and all the ultraviolet region. The GW approximation for the electronic self-energy has been used to tackle the one-particle excitations problem, enabling us to determine the electronic energy bands and densities of states of this fluoride. For the optical properties, the two-particle effects calculated with the Bethe–Salpeter scheme turn out to play a fundamental role. A bound exciton positioned at about 1.5 eV below the one-particle gap is forecasted. The optical absorption and the electron energy loss spectra together with other optical functions are in good agreement with the experimental results up to 15 eV. In fact, for this part of the spectrum a self-consistent one-particle scheme along with the Bethe–Salpeter approach produces notable results. Less satisfactory results for the higher energy region in the spectra have been produced with the proposed method. Possible causes of these discrepancies are fully discussed.

Emiliano Cadelano; Jürgen Furthmüller; Giancarlo Cappellini; Friedhelm Bechstedt

2014-01-01T23:59:59.000Z

430

EBIT - Electronic Beam Ion Trap: N Divison experimental physics annual report 1995  

SciTech Connect

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.

Schneider, D. [ed.

1996-10-01T23:59:59.000Z

431

A gas-jet transport and catcher technique for on-line production of radioactive ion beams using an electron cyclotron resonance ion-source  

SciTech Connect

Radioactive ion beams (RIB) have been produced on-line, using a gas-jet recoil transport coupled Electron Cyclotron Resonance (ECR) ion-source at the VECC-RIB facility. Radioactive atoms/molecules carried through the gas-jet were stopped in a catcher placed inside the ECR plasma chamber. A skimmer has been used to remove bulk of the carrier gas at the ECR entrance. The diffusion of atoms/molecules through the catcher has been verified off-line using stable isotopes and on-line through transmission of radioactive reaction products. Beams of {sup 14}O (71 s), {sup 42}K (12.4 h), {sup 43}K (22.2 h), and {sup 41}Ar (1.8 h) have been produced by bombarding nitrogen and argon gas targets with proton and alpha particle beams from the K130 cyclotron at VECC. Typical measured intensity of RIB at the separator focal plane is found to be a few times 10{sup 3} particles per second (pps). About 3.2 Multiplication-Sign 10{sup 3} pps of 1.4 MeV {sup 14}O RIB has been measured after acceleration through a radiofrequency quadrupole linac. The details of the gas-jet coupled ECR ion-source and RIB production experiments are presented along with the plans for the future.

Naik, V.; Chakrabarti, A.; Bhattacharjee, M.; Karmakar, P.; Bandyopadhyay, A.; Dechoudhury, S.; Mondal, M.; Pandey, H. K.; Lavanyakumar, D.; Mandi, T. K.; Dutta, D. P.; Kundu Roy, T.; Bhowmick, D.; Sanyal, D.; Srivastava, S. C. L.; Ray, A.; Ali, Md. S. [Variable Energy Cyclotron Centre (VECC), Sector-1, Block-AF, Bidhan Nagar, Kolkata 700064 (India); Bhattacharjee, S. [UGC-DAE CSR, Kolkata Centre, III/LB-8, Bidhan Nagar, Kolkata 700098 (India)

2013-03-15T23:59:59.000Z

432

Electron Fluid Description of Wave-Particle Interactions in Strong Buneman Turbulence  

E-Print Network (OSTI)

To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation during Buneman instability in force-free current sheets. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions in Buneman instability can be approximately described by a set of electron fluid equations. These equations show that the energy dissipation and momentum transports along current sheets are locally quasi-static but globally non-static and irreversible. Turbulence drag dissipates both the streaming energy of current sheets and the associated magnetic energy. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons. The net loss of streaming energy is converted into the heat of electrons moving along the magnetic field and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation that rela...

Che, H

2014-01-01T23:59:59.000Z

433

MAGNETIC FIELD GENERATION AND PARTICLE ENERGIZATION AT RELATIVISTIC SHEAR BOUNDARIES IN COLLISIONLESS ELECTRON-POSITRON PLASMAS  

SciTech Connect

Using particle-in-cell simulations, we study the kinetic physics of relativistic shear flow in collisionless electron-positron (e+e-) plasmas. We find efficient magnetic field generation and particle energization at the shear boundary, driven by streaming instabilities across the shear interface and sustained by the shear flow. Nonthermal, anisotropic high-energy particles are accelerated across field lines to produce a power-law tail turning over just below the shear Lorentz factor. These results have important implications for the dissipation and radiation of jets in blazars and gamma-ray bursts.

Liang, Edison; Smith, Ian [Rice University, MS 108, 6100 Main Street, Houston, TX 77005 (United States); Boettcher, Markus, E-mail: liang@rice.edu, E-mail: iansmith@rice.edu, E-mail: boettchm@ohio.edu [Physics and Astronomy Department, Ohio University, Athens, OH 45701 (United States)

2013-04-01T23:59:59.000Z

434

Potential For Laser-Induced Microbunching Studies with the 3-MHZ-Rate Electron Beams at ASTA  

E-Print Network (OSTI)

Investigations of the laser-induced microbunching as it is related to time-sliced electron-beam diagnostics and high-gain-harmonic generation (HGHG) free-electron lasers using bright electron beams are proposed for the ASTA facility. Initial tests at 40-50 MeV with an amplified 800-nm seed laser beam co-propagating with the electron beam through a short undulator (or modulator) tuned for the resonance condition followed by transport through a subsequent chicane will result in energy modulation and z-density modulation (microbunching), respectively. The latter microbunching will result in generation of coherent optical or UV transition radiation (COTR, CUVTR) at a metal converter screen which can reveal slice beam size, centroid, and energy spread. Additionally, direct assessment of the microbunching factors related to HGHG by measurement of the COTR intensity and harmonic content after the chicane as a function of seed laser power and beam parameters will be done. These experiments will be performed using the...

Lumpkin, A H; Byrd, J M; Wilcox, R B

2014-01-01T23:59:59.000Z

435

Relationship between electron density and effective densities of body tissues for stopping, scattering, and nuclear interactions of proton and ion beams  

SciTech Connect

Purpose: In treatment planning of charged-particle radiotherapy, patient heterogeneity is conventionally modeled as variable-density water converted from CT images to best reproduce the stopping power, which may lead to inaccuracies in the handling of multiple scattering and nuclear interactions. Although similar conversions can be defined for these individual interactions, they would be valid only for specific CT systems and would require additional tasks for clinical application. This study aims to improve the practicality of the interaction-specific heterogeneity correction. Methods: The authors calculated the electron densities and effective densities for stopping power, multiple scattering, and nuclear interactions of protons and ions, using the standard elemental-composition data for body tissues to construct the invariant conversion functions. The authors also simulated a proton beam in a lung-like geometry and a carbon-ion beam in a prostate-like geometry to demonstrate the procedure and the effects of the interaction-specific heterogeneity correction. Results: Strong correlations were observed between the electron density and the respective effective densities, with which the authors formulated polyline conversion functions. Their effects amounted to 10% differences in multiple-scattering angle and nuclear interaction mean free path for bones compared to those in the conventional heterogeneity correction. Although their realistic effect on patient dose distributions would be generally small, it could be at the level of a few percent when a carbon-ion beam traverses a large bone. Conclusions: The present conversion functions are invariant and may be incorporated in treatment planning systems with a common function relating CT number to electron density. This will enable improved beam dose calculation while minimizing initial setup and quality management of the user's specific system.

Kanematsu, Nobuyuki; Inaniwa, Taku; Koba, Yusuke [Department of Accelerator and Medical Physics, Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

2012-02-15T23:59:59.000Z

436

Ion-acoustic waves in a plasma consisting of adiabatic warm ions, nonisothermal electrons, and a weakly relativistic electron beam: Linear and higher-order nonlinear effects  

SciTech Connect

The nonlinear propagation of finite amplitude ion acoustic solitary waves in a plasma consisting of adiabatic warm ions, nonisothermal electrons, and a weakly relativistic electron beam is studied via a two-fluid model. A multiple scales technique is employed to investigate the nonlinear regime. The existence of the electron beam gives rise to four linear ion acoustic modes, which propagate at different phase speeds. The numerical analysis shows that the propagation speed of two of these modes may become complex-valued (i.e., waves cannot occur) under conditions which depend on values of the beam-to-background-electron density ratio {alpha}, the ion-to-free-electron temperature ratio {sigma}, and the electron beam velocity v{sub 0}; the remaining two modes remain real in all cases. The basic set of fluid equations are reduced to a Schamel-type equation and a linear inhomogeneous equation for the first and second-order potential perturbations, respectively. Stationary solutions of the coupled equations are derived using a renormalization method. Higher-order nonlinearity is thus shown to modify the solitary wave amplitude and may also deform its shape, even possibly transforming a simple pulse into a W-type curve for one of the modes. The dependence of the excitation amplitude and of the higher-order nonlinearity potential correction on the parameters {alpha}, {sigma}, and v{sub 0} is numerically investigated.

Esfandyari-Kalejahi, A. [Faculty of Science, Department of Physics, Azerbaijan University of Tarbiat Moallem, 51745-406 Tabriz (Iran, Islamic Republic of); Kourakis, I. [Center for Plasma Physics (CPP), Department of Physics and Astronomy, Queen's University Belfast, BT7 1 NN Northern Ireland (United Kingdom); Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Shukla, P. K. [Institut fuer Theoretische Physik IV, Fakultaet fuer Physik und Astronomie, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2008-02-15T23:59:59.000Z

437

EBIT (Electron Beam Ion Trap), N-Division Experimental Physics. Annual report, 1994  

SciTech Connect

The experimental groups in the Electron Beam Ion Trap (EBIT) program continue to perform front-line research with trapped and extracted highly charged ions (HCI) in the areas of ion/surface interactions, atomic spectroscopy, electron-ion interaction and structure measurements, highly charged ion confinement, and EBIT development studies. The ion surface/interaction studies which were initiated five years ago have reached a stage where they an carry out routine investigations, as well as produce breakthrough results towards the development of novel nanotechnology. At EBIT and SuperEBIT studies of the x-ray emission from trapped ions continue to produce significant atomic structure data with high precision for few electron systems of high-Z ions. Furthermore, diagnostics development for magnetic and laser fusion, supporting research for the x-ray laser and weapons programs, and laboratory astrophysics experiments in support of NASA`s astrophysics program are a continuing effort. The two-electron contributions to the binding energy of helium like ions were measured for the first time. The results are significant because their precision is an order of magnitude better than those of competing measurements at accelerators, and the novel technique isolates the energy corrections that are the most interesting. The RETRAP project which was initiated three years ago has reached a stage where trapping, confining and electronic cooling of HCI ions up to Th{sup 80+} can be performed routinely. Measurements of the rates and cross sections for electron transfer from H{sub 2} performed to determine the lifetime of HCI up to Xe{sup q+} and Th{sup q+} (35 {le} q {le} 80) have been studied at mean energies estimated to be {approximately} 5 q eV. This combination of heavy ions with very high charges and very low energies is rare in nature, but may be encountered in planned fusion energy demonstration devices, in highly charged ion sources, or in certain astrophysical events.

Schneider, D. [ed.

1995-10-01T23:59:59.000Z

438

Theoretical study of particle transport in electron internal transport barriers in TCV  

SciTech Connect

Previous results from the analysis of fully non inductively sustained electron internal transport barriers (eITBs) in TCV show that a strong coupling exists between electron temperature and density profiles inside the barrier. A phenomenology that is completely different from the standard L-mode is observed . New experimental results assess transient phases to calculate particle convection and diffusion coefficients, allowing also to discuss the role of neoclassical transport. Gyrokinetic and gyrofluid analysis of steady-state eITBs provide tools to understand the mechanism that drive the observed density peaking in advanced scenarios with internal transport barriers and dominant electron heating.

Fable, E.; Sauter, O.; Marinoni, A.; Zucca, C. [Centre de Recherches en Physique des Plasmas, Association EURATOM -- Confederation Suisse, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

2006-11-30T23:59:59.000Z

439

Method and apparatus for charged particle propagation  

DOE Patents (OSTI)

A method and apparatus are provided for propagating charged particles from a vacuum to a higher pressure region. A generator includes an evacuated chamber having a gun for discharging a beam of charged particles such as an electron beam or ion beam. The beam is discharged through a beam exit in the chamber into a higher pressure region. A plasma interface is disposed at the beam exit and includes a plasma channel for bounding a plasma maintainable between a cathode and an anode disposed at opposite ends thereof. The plasma channel is coaxially aligned with the beam exit for propagating the beam from the chamber, through the plasma, and into the higher pressure region. The plasma is effective for pumping down the beam exit for preventing pressure increase in the chamber and provides magnetic focusing of the beam discharged into the higher pressure region 24. 7 figs.

Hershcovitch, A.

1996-11-26T23:59:59.000Z

440

Behavior of liquid lithium jet irradiated by 1 MeV electron beams up to 20 kW  

SciTech Connect

Experiments were conducted to demonstrate the stable operation of the windowless liquid lithium target under extreme thermal loads that are equivalent to uranium beams from the proposed Rare Isotope Accelerator (RIA) driver linac. The cross section of the windowless liquid lithium target was 5 mmx10 mm and the velocity of the liquid lithium was varied up to 6 m/s. Thermal loads up to 20 kW within a beam spot of 1 mm in diameter were applied on the windowless liquid lithium target by 1 MeV electron beams. The maximum power density and total power deposited within the target was equivalent to that of a 200 kW, 400 MeV/u uranium beam. It was demonstrated that the windowless liquid lithium target flowing at as low as 1.8 m/s stably operates at a beam energy deposition up to 20 kW without disruption or excess vaporization.

Nolen, J.A.; Reed, C.B.; Novick, V.J.; Specht, J.R.; Bogaty, J.M.; Plotkin, P.; Momozaki, Y. [Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Nuclear Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Physics Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Energy Technology Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States); Nuclear Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

2005-07-15T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
While these samples are representative of the content of NLEBeta,
they are not comprehensive nor are they the most current set.
We encourage you to perform a real-time search of NLEBeta
to obtain the most current and comprehensive results.


441

GPU-optimized Code for Long-term Simulations of Beam-beam Effects in Colliders  

SciTech Connect

We report on the development of the new code for long-term simulation of beam-beam effects in particle colliders. The underlying physical model relies on a matrix-based arbitrary-order symplectic particle tracking for beam transport and the Bassetti-Erskine approximation for beam-beam interaction. The computations are accelerated through a parallel implementation on a hybrid GPU/CPU platform. With the new code, a previously computationally prohibitive long-term simulations become tractable. We use the new code to model the proposed medium-energy electron-ion collider (MEIC) at Jefferson Lab.

Roblin, Yves [JLAB; Morozov, Vasiliy [JLAB; Terzic, Balsa [JLAB; Aturban, Mohamed A. [Old Dominion University; Ranjan, D. [Old Dominion University; Zubair, Mohammed [Old Dominion University

2013-06-01T23:59:59.000Z

442

Adiabatic electron response and solitary wave generation by trapped particle nonlinearity in a hydrogen plasma  

SciTech Connect

The finite amplitude ion acoustic waves that trap electrons modify the structure of the evolving nonlinear soliton solutions. In the numerical simulations, self-consistently generated solitary waves are studied that emerge as a result of a current driven microinstability growing the ion acoustic mode in a collisionless Vlasov plasma. The growth saturates as a result of nonlinear effects governed by a combination of nonlinearities originating from the hydrodynamic model and kinetic particle trapping effects. The resulting solitary waves also coexist with a finite current and an electron plasma wave capable of perturbing the trapping potential. The results of multiscale simulation are analyzed and characterized following the kinetic prescription of undamped trapped particle mode in the form of phase space vortex solutions that are generalized form of Sagdeev's solitons and obey the solutions of a modified Korteweg-de Vries equation, accounting for a stronger nonlinearity originating from the electron trapping.

Mandal, Debraj; Sharma, Devendra [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

2014-10-15T23:59:59.000Z

443

A novel approach in electron beam radiation therapy of lips carcinoma: A Monte Carlo study  

SciTech Connect

Purpose: Squamous cell carcinoma (SCC) is commonly treated by electron beam radiotherapy (EBRT) followed by a boost via brachytherapy. Considering the limitations associated with brachytherapy, in this study, a novel boosting technique in EBRT of lip carcinoma using an internal shield as an internal dose enhancer tool (IDET) was evaluated. An IDET is referred to a partially covered internal shield located behind the lip. It was intended to show that while the backscattered electrons are absorbed in the portion covered with a low atomic number material, they will enhance the target dose in the uncovered area. Methods: Monte-Carlo models of 6 and 8 MeV electron beams were developed using BEAMnrc code and were validated against experimental measurements. Using the developed models, dose distributions in a lip phantom were calculated and the effect of an IDET on target dose enhancement was evaluated. Typical lip thicknesses of 1.5 and 2.0 cm were considered. A 5 Multiplication-Sign 5 cm{sup 2} of lead covered by 0.5 cm of polystyrene was used as an internal shield, while a 4 Multiplication-Sign 4 cm{sup 2} uncovered area of the shield was used as the dose enhancer. Results: Using the IDET, the maximum dose enhancement as a percentage of dose at d{sub max} of the unshielded field was 157.6% and 136.1% for 6 and 8 MeV beams, respectively. The best outcome was achieved for lip thickness of 1.5 cm and target thickness of less than 0.8 cm. For lateral dose coverage of planning target volume, the 80% isodose curve at the lip-IDET interface showed a 1.2 cm expansion, compared to the unshielded field. Conclusions: This study showed that a boost concomitant EBRT of lip is possible by modifying an internal shield into an IDET. This boosting method is especially applicable to cases in which brachytherapy faces limitations, such as small thicknesses of lips and targets located at the buccal surface of the lip.

Shokrani, Parvaneh [Medical Physics and Medical Engineering Department, School of Medicine, Isfahan University of Medical Sciences, Isfahan 81746-73461 (Iran, Islamic Republic of); Baradaran-Ghahfarokhi, Milad [Medical Physics and Medical Engineering Department, School of Medicine, Isfahan University of Medical Sciences, Isfahan 81746-73461, Iran and Medical Radiation Engineering Department, Faculty of Advanced Sciences and Technologies, Isfahan University, Isfahan 81746-73441 (Iran, Islamic Republic of); Zadeh, Maryam Khorami [Medical Physics Department, School of Medicine, Ahwaz Jundishapour University of Medical Sciences, Ahwaz 15794-61357 (Iran, Islamic Republic of)

2013-04-15T23:59:59.000Z

444

Faraday cup with nanosecond response and adjustable impedance for fast electron beam characterization  

SciTech Connect

A movable Faraday cup design with simple structure and adjustable impedance is described in this work. This Faraday cup has external adjustable shunt resistance for self-biased measurement setup and 50 {Omega} characteristic impedance to match with 50 {Omega} standard BNC coaxial cable and vacuum feedthroughs for nanosecond-level pulse signal measurements. Adjustable shunt resistance allows self-biased measurements to be quickly acquired to determine the electron energy distribution function. The performance of the Faraday cup is validated by tests of response time and amplitude of output signal. When compared with a reference source, the percent difference of the Faraday cup signal fall time is less than 10% for fall times greater than 10 ns. The percent difference of the Faraday cup signal pulse width is below 6.7% for pulse widths greater than 10 ns. A pseudospark-generated electron beam is used to compare the amplitude of the Faraday cup signal with a calibrated F-70 commercial current transformer. The error of the Faraday cup output amplitude is below 10% for the 4-14 kV tested pseudospark voltages. The main benefit of this Faraday cup is demonstrated by adjusting the external shunt resistance and performing the self-biased method for obtaining the electron energy distribution function. Results from a 4 kV pseudospark discharge indicate a ''double-humped'' energy distribution.

Hu Jing; Rovey, Joshua L. [Missouri University of Science and Technology (Formerly University of Missouri-Rolla), Rolla, Missouri 65409 (United States)

2011-07-15T23:59:59.000Z

445

E-Print Network 3.0 - annular electron beam Sample Search Results  

NLE Websites -- All DOE Office Websites (Extended Search)

TRANSDUCER Summary: -dimensional format). (5) Simulated the formation of nondiffracting beams as the number of annular transducer elements... and the steering nondiffracting beams...

446

Novel scheme for the preparation of transmission electron microscopy specimens with a focused ion beam  

Science Journals Connector (OSTI)

A novel scheme is presented for the preparation of cross?section transmission electron microscopy(TEM) specimens with a focused ion beam(FIB). This scheme is particularly suitable for highly structured substrates such as integrated circuits. The specimen is made by cutting a thin slice of material from the substrate by sputtering with the FIB. The position of the specimen can be selected with submicron resolution. The specimen is subsequently removed from the substrate and transported to a standard TEM?specimen holder. A specimen ready for TEM inspection can be prepared within 2 hs. The samples are of excellent quality as is illustrated with cross?section TEM images of FIB?made specimens of an electrically programmable read?only memory.

M. H. F. Overwijk; F. C. van den Heuvel; C. W. T. Bulle?Lieuwma

1993-01-01T23:59:59.000Z

447

New Measurements of the Transverse Beam Asymmetry for Elastic Electron Scattering from Selected Nuclei  

E-Print Network (OSTI)

We have measured the beam-normal single-spin asymmetry $A_n$ in the elastic scattering of 1-3 GeV transversely polarized electrons from $^1$H and for the first time from $^4$He, $^{12}$C, and $^{208}$Pb. For $^1$H, $^4$He and $^{12}$C, the measurements are in agreement with calculations that relate $A_n$ to the imaginary part of the two-photon exchange amplitude including inelastic intermediate states. Surprisingly, the $^{208}$Pb result is significantly smaller than the corresponding prediction using the same formalism. These results suggest that a systematic set of new $A_n$ measurements might emerge as a new and sensitive probe of the structure of heavy nuclei.

The HAPPEX; PREX Collaborations; :; S. Abrahamyan; A. Acha; A. Afanasev; Z. Ahmed; H. Albataineh; K. Aniol; D. S. Armstrong; W. Armstrong; J. Arrington; T. Averett; B. Babineau; S. L. Bailey; J. Barber; A. Barbieri; A. Beck; V. Bellini; R. Beminiwattha; H. Benaoum; J. Benesch; F. Benmokhtar; P. Bertin; T. Bielarski; W. Boeglin; P. Bosted; F. Butaru; E. Burtin; J. Cahoon; A. Camsonne; M. Canan; P. Carter; C. C. Chang; G. D. Cates; Y. C. Chao; C. Chen; J. P. Chen; Seonho Choi; E. Chudakov; E. Cisbani; B. Craver; F. Cusanno; M. M. Dalton; R. De Leo; K. de Jager; W. Deconinck; P. Decowski; D. Deepa; X. Deng; A. Deur; D. Dutta; A. Etile; C. Ferdi; R. J. Feuerbach; J. M. Finn; D. Flay; G. B. Franklin; M. Friend; S. Frullani; E. Fuchey; S. A. Fuchs; K. Fuoti; F. Garibaldi; E. Gasser; R. Gilman; A. Giusa; A. Glamazdin; L. E. Glesener; J. Gomez; M. Gorchtein; J. Grames; K. Grimm; C. Gu; O. Hansen; J. Hansknecht; O. Hen; D. W. Higinbotham; R. S. Holmes; T. Holmstrom; C. J. Horowitz; J. Hoskins; J. Huang; T. B. Humensky; C. E. Hyde; H. Ibrahim; F. Itard; C. M. Jen; E. Jensen; X. Jiang; G. Jin; S. Johnston; J. Katich; L. J. Kaufman; A. Kelleher; K. Kliakhandler; P. M. King; A. Kolarkar; S. Kowalski; E. Kuchina; K. S. Kumar; L. Lagamba; D. Lambert; P. LaViolette; J. Leacock; J. Leckey IV; J. H. Lee; J. J. LeRose; D. Lhuillier; R. Lindgren; N. Liyanage; N. Lubinsky; J. Mammei; F. Mammoliti; D. J. Margaziotis; P. Markowitz; M. Mazouz; K. McCormick; A. McCreary; D. McNulty; D. G. Meekins; L. Mercado; Z. E. Meziani; R. W. Michaels; M. Mihovilovic; B. Moffit; P. Monaghan; N. Muangma; C. Munoz-Camacho; S. Nanda; V. Nelyubin; D. Neyret; Nuruzzaman; Y. Oh; K. Otis; A. Palmer; D. Parno; K. D. Paschke; S. K. Phillips; M. Poelker; R. Pomatsalyuk; M. Posik; M. Potokar; K. Prok; A. J. R. Puckett; X. Qian; Y. Qiang; B. Quinn; A. Rakhman; P. E. Reimer; B. Reitz; S. Riordan; J. Roche; P. Rogan; G. Ron; G. Russo; K. Saenboonruang; A. Saha; B. Sawatzky; A. Shahinyan; R. Silwal; J. Singh; S. Sirca; K. Slifer; R. Snyder; P. Solvignon; P. A. Souder; M. L. Sperduto; R. Subedi; M. L. Stutzman; R. Suleiman; V. Sulkosky; C. M. Sutera; W. A. Tobias; W. Troth; G. M. Urciuoli; P. Ulmer; A. Vacheret; E. Voutier; B. Waidyawansa; D. Wang; K. Wang; J. Wexler; A. Whitbeck; R. Wilson; B. Wojtsekhowski; X. Yan; H. Yao; Y. Ye; Z. Ye; V. Yim; L. Zana; X. Zhan; J. Zhang; Y. Zhang; X. Zheng; V. Ziskin; P. Zhu

2012-10-12T23:59:59.000Z

448

Electron beam induced modifications in crystalline structure of polyvinylidene fluoride/nanoclay composites  

Science Journals Connector (OSTI)

Abstract PVDF/nanoclay nanocomposites were prepared via melt mixing method. The intercalated dispersion of the nanoclay in PVDF matrix was confirmed by XRD. According to FTIR, DSC and XRD results, the presence of nanoclay facilitated transition from ?-to-? crystalline phase. Electron beam irradiation decreased the melting point of the nanocomposites. The decrease in melting point of the nanocomposites was about 11 °C at 500 kGy. The crystallinity of nanocomposites increased at an irradiation dose of 100 kGy and decreased at higher irradiation doses. The extent of crosslinking of the nanocomposites increased significantly with irradiation up to 300 kGy. The nanoclay intensified the increase in yield strength with irradiation doses up to 300 kGy. The combination of nanoclay and irradiation had a synergistic effect on the increase of yield strength.

Peyman Rahmani; Susan Dadbin; Masoud Frounchi

2014-01-01T23:59:59.000Z

449

Preparation and characterization of indium zinc oxide thin films by electron beam evaporation technique  

SciTech Connect

In this work, the preparation of In{sub 2}O{sub 3}-ZnO thin films by electron beam evaporation technique on glass substrates is reported. Optical and electrical properties of these films were investigated. The effect of dopant amount and annealing temperature on the optical and electrical properties of In{sub 2}O{sub 3}-ZnO thin films was also studied. Different amount of ZnO was used as dopant and the films were annealed at different temperature. The results showed that the most crystalline, transparent and uniform films with lowest resistivity were obtained using 25 wt% of ZnO annealed at 500 {sup o}C.

Keshavarzi, Reza [Chemistry Department, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)] [Chemistry Department, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Mirkhani, Valiollah, E-mail: mirkhani@sci.ui.ac.ir [Chemistry Department, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)] [Chemistry Department, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Moghadam, Majid, E-mail: moghadamm@sci.ui.ac.ir [Chemistry Department, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of) [Chemistry Department, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Department of Nanotechnology Engineering, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Tangestaninejad, Shahram; Mohammadpoor-Baltork, Iraj [Chemistry Department, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)] [Chemistry Department, Catalysis Division, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Fallah, Hamid Reza; Dastjerdi, Mohammad Javad Vahid; Modayemzadeh, Hamed Reza [Department of Physics, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)] [Department of Physics, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)

2011-04-15T23:59:59.000Z

450

ADVANCED X-BAND TEST ACCELERATOR FOR HIGH BRIGHTNESS ELECTRON AND GAMMA RAY BEAMS  

SciTech Connect

In support of Compton scattering gamma-ray source efforts at LLNL, a multi-bunch test stand is being developed to investigate accelerator optimization for future upgrades. This test stand will enable work to explore the science and technology paths required to boost the current 10 Hz monoenergetic gamma-ray (MEGa-Ray) technology to an effective repetition rate exceeding 1 kHz, potentially increasing the average gamma-ray brightness by two orders of magnitude. Multiple bunches must be of exceedingly high quality to produce narrow-bandwidth gamma-rays. Modeling efforts will be presented, along with plans for a multi-bunch test stand at LLNL. The test stand will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. The photoinjector will be a high gradient standing wave structure, featuring a dual feed racetrack coupler. The accelerator will increase the electron energy so that the emittance can be measured using quadrupole scanning techniques. Multi-bunch diagnostics will be developed so that the beam quality can be measured and compared with theory. Design will be presented with modeling simulations, and layout plans.

Marsh, R A; Anderson, S G; Barty, C P; Chu, T S; Ebbers, C A; Gibson, D J; Hartemann, F V; Adolphsen, C; Jongewaard, E N; Raubenheimer, T; Tantawi, S G; Vlieks, A E; Wang, J W

2010-05-12T23:59:59.000Z

451

Advanced X-Band Test Accelerator for High Brightness Electron and Gamma Ray Beams  

SciTech Connect

In support of Compton scattering gamma-ray source efforts at LLNL, a multi-bunch test stand is being developed to investigate accelerator optimization for future upgrades. This test stand will enable work to explore the science and technology paths required to boost the current 10 Hz monoenergetic gamma-ray (MEGa-Ray) technology to an effective repetition rate exceeding 1 kHz, potentially increasing the average gamma-ray brightness by two orders of magnitude. Multiple bunches must be of exceedingly high quality to produce narrow-bandwidth gamma-rays. Modeling efforts will be presented, along with plans for a multi-bunch test stand at LLNL. The test stand will consist of a 5.5 cell X-band rf photoinjector, single accelerator section, and beam diagnostics. The photoinjector will be a high gradient standing wave structure, featuring a dual feed racetrack coupler. The accelerator will increase the electron energy so that the emittance can be measured using quadrupole scanning techniques. Multi-bunch diagnostics will be developed so that the beam quality can be measured and compared with theory. Design will be presented with modeling simulations, and layout plans.

Marsh, Roark; /LLNL, Livermore; Anderson, Scott; /LLNL, Livermore; Barty, Christopher; /LLNL, Livermore; Chu, Tak Sum; /LLNL, Livermore; Ebbers, Chris; /LLNL, Livermore; Gibson, David; /LLNL, Livermore; Hartemann, Fred; /LLNL, Livermore; Adolphsen, Chris; /SLAC; Jongewaard, Erik; /SLAC; Raubenheimer, Tor; /SLAC; Tantawi, Sami; /SLAC; Vlieks, Arnold; /SLAC; Wang, Juwen; /SLAC

2012-07-03T23:59:59.000Z

452

An Ultra-Bright Pulsed Electron Beam with Low Longitudinal Emittance  

E-Print Network (OSTI)

Abstract Most existing electron sources extract electrons? f ? 2 10 ?3 . An electron source with these parameters canble applications for this electron source include angstrom-

2005-01-01T23:59:59.000Z

453

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

E-Print Network (OSTI)

current, high brightness electron source plays a key role incommunity. Low emittance electron source using electronsThe electron current density from this source is about 110

2008-01-01T23:59:59.000Z

454

Particle accelerator employing transient space charge potentials  

DOE Patents (OSTI)

The invention provides an accelerator for ions and charged particles. The plasma is generated and confined in a magnetic mirror field. The electrons of the plasma are heated to high temperatures. A series of local coils are placed along the axis of the magnetic mirror field. As an ion or particle beam is directed along the axis in sequence the coils are rapidly pulsed creating a space charge to accelerate and focus the beam of ions or charged particles.

Post, Richard F. (Walnut Creek, CA)

1990-01-01T23:59:59.000Z

455

On the usage of electron beam as a tool to produce radioactive isotopes in photo-nuclear reactions  

E-Print Network (OSTI)

We treat the bremsstrahlung induced by initial electron beam in converter, and the production of a desirable radio-isotope due to the photo-nuclear reaction caused by this bremsstrahlung. By way of illustration, the yield of a number of some, the most in practice applicable, radio-isotopes is evaluated. The acquired findings persuade us that usage of modern electron accelerators offers a practicable way to produce the radio-isotopes needful nowadays for various valuable applications in the nuclear medicine.

G. G. Bunatian; V. G. Nikolenko; A. B. Popov

2010-12-22T23:59:59.000Z

456

Polythiophene-based charge dissipation layer for electron beam lithography of zinc oxide and gallium nitride  

Science Journals Connector (OSTI)

The ability of thin polythiophene layers to dissipate accumulated charge in the electron beam lithography (EBL) of wide bandgap semiconductors such as zinc oxide and gallium nitride is demonstrated. A quick and inexpensive processing method is demonstrated for EBL exposure of dense and high-resolution patterns in a hydrogen silsesquioxane (HSQ) negative-tone resistdeposited on bulk ZnO samples and with GaN/AlN on sapphire substrates. F