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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.


1

Characterisation of electron beams from laser-driven particle accelerators  

Science Conference Proceedings (OSTI)

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

2

Particle beam injection system  

SciTech Connect

This invention provides a poloidal divertor for stacking counterstreaming ion beams to provide high intensity colliding beams. To this end, method and apparatus are provided that inject high energy, high velocity, ordered, atomic deuterium and tritium beams into a lower energy, toroidal, thermal equilibrium, neutral, target plasma column that is magnetically confined along an endless magnetic axis in a strong restoring force magnetic field having helical field lines to produce counterstreaming deuteron and triton beams that are received bent, stacked and transported along the endless axis, while a poloidal divertor removes thermal ions and electrons all along the axis to increase the density of the counterstreaming ion beams and the reaction products resulting therefrom. By balancing the stacking and removal, colliding, strong focused particle beams, reaction products and reactions are produced that convert one form of energy into another form of energy.

Jassby, Daniel L. (Princeton, NJ); Kulsrud, Russell M. (Princeton, NJ)

1977-01-01T23:59:59.000Z

3

Optical transition radiation used in the diagnostic of low energy and low current electron beams in particle accelerators  

Science Conference Proceedings (OSTI)

Optical transition radiation (OTR) plays an important role in beam diagnostics for high energy particle accelerators. Its linear intensity with beam current is a great advantage as compared to fluorescent screens, which are subject to saturation. Moreover, the measurement of the angular distribution of the emitted radiation enables the determination of many beam parameters in a single observation point. However, few works deals with the application of OTR to monitor low energy beams. In this work we describe the design of an OTR based beam monitor used to measure the transverse beam charge distribution of the 1.9-MeV electron beam of the linac injector of the IFUSP microtron using a standard vision machine camera. The average beam current in pulsed operation mode is of the order of tens of nano-Amps. Low energy and low beam current make OTR observation difficult. To improve sensitivity, the beam incidence angle on the target was chosen to maximize the photon flux in the camera field-of-view. Measurements that assess OTR observation (linearity with beam current, polarization, and spectrum shape) are presented, as well as a typical 1.9-MeV electron beam charge distribution obtained from OTR. Some aspects of emittance measurement using this device are also discussed.

Silva, T. F.; Bonini, A. L.; Lima, R. R.; Maidana, N. L.; Malafronte, A. A.; Pascholati, P. R.; Vanin, V. R.; Martins, M. N. [Institute of Physics, University of Sao Paulo, CP 66318, 05315-970 Sao Paulo, SP (Brazil)

2012-09-15T23:59:59.000Z

4

Virtually distortion-free imaging system for large field, high resolution lithography using electrons, ions or other particle beams  

DOE Patents (OSTI)

Virtually distortion free large field high resolution imaging is performed using an imaging system which contains large field distortion or field curvature. A reticle is imaged in one direction through the optical system to form an encoded mask. The encoded mask is then imaged back through the imaging system onto a wafer positioned at the reticle position. Particle beams, including electrons, ions and neutral particles, may be used as well as electromagnetic radiation.

Hawryluk, A.M.; Ceglio, N.M.

1991-04-10T23:59:59.000Z

5

Virtually distortion-free imaging system for large field, high resolution lithography using electrons, ions or other particle beams  

DOE Patents (OSTI)

Virtually distortion free large field high resolution imaging is performed using an imaging system which contains large field distortion or field curvature. A reticle is imaged in one direction through the optical system to form an encoded mask. The encoded mask is then imaged back through the imaging system onto a wafer positioned at the reticle position. Particle beams, including electrons, ions and neutral particles, may be used as well as electromagnetic radiation.

Hawryluk, Andrew M. (Modesto, CA); Ceglio, Natale M. (Livermore, CA)

1993-01-01T23:59:59.000Z

6

Relativistic electron beam generator  

DOE Patents (OSTI)

A relativistic electron beam generator for laser media excitation is described. The device employs a diode type relativistic electron beam source having a cathode shape which provides a rectangular output beam with uniform current density.

Mooney, L.J.; Hyatt, H.M.

1975-11-11T23:59:59.000Z

7

Pulsed electron beam precharger  

Science Conference Proceedings (OSTI)

Florida State University is investigating the concept of pulsed electron beams for fly ash precipitation. This report describes the results and data on three of the subtasks of this project and preliminary work only on the remaining five subtasks. Described are the modification of precharger for pulsed and DC energization of anode; installation of the Q/A measurement system; and modification and installation of pulsed power supply to provide both pulsed and DC energization of the anode. The other tasks include: measurement of the removal efficiency for monodisperse simulated fly ash particles; measurement of particle charge; optimization of pulse energization schedule for maximum removal efficiency; practical assessment of results; and measurement of the removal efficiency for polydisperse test particles. 15 figs., 1 tab. (CK)

Finney, W.C. (ed.); Shelton, W.N.

1990-01-01T23:59:59.000Z

8

Electron beam device  

DOE Patents (OSTI)

This patent pertains to an electron beam device in which a hollow target is symmetrically irradiated by a high energy, pulsed electron beam about its periphery and wherein the outer portion of the target has a thickness slightly greater than required to absorb the electron beam pulse energy. (auth)

Beckner, E.H.; Clauser, M.J.

1975-08-12T23:59:59.000Z

9

Electron Beam Melting (EBM)  

Science Conference Proceedings (OSTI)

Oct 18, 2011 ... Additive Manufacturing of Metals: Electron Beam Melting (EBM) I Sponsored by: MS&T Organization Program Organizers: Ian D. Harris, EWI; ...

10

Electron Beam Melting  

Science Conference Proceedings (OSTI)

Oct 9, 2012 ... Additive Manufacturing of Metals: Electron Beam Melting Program Organizers: Ian Harris, EWI; Ola Harrysson, North Carolina State University; ...

11

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

12

Electron and laser beam welding  

SciTech Connect

This book contains 22 selections. Some of the titles are: Laser welding of chandelles to the plates of the sommier employed in the nuclear power plant core; Electron beam welding of hobbing cutters; Sealing welds in electron beam welding of thick metals; Development and application of high power electron beam welding; Electron beam welding of dissimilar metals (niobium, molybdenum, porous tungsten-molybdenum); Status of electron beam welding in the United States of America; and Electron and laser beam welding in Japan.

1986-01-01T23:59:59.000Z

13

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

14

Electron Beam Powder Bed Processes  

Science Conference Proceedings (OSTI)

Advanced Materials, Processes and Applications for Additive Manufacturing : Electron Beam Powder Bed Processes Program Organizers: Andrzej ...

15

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

16

Particle beam fusion  

SciTech Connect

Today, in keeping with Sandia Laboratories` designation by the Department of Energy as the lead laboratory for the pulsed power approach to fusion, its efforts include major research activities and the construction of new facilities at its Albuquerque site. Additionally, in its capacity as lead laboratory, Sandia coordinates DOE-supported pulsed power fusion work at other government operated laboratories, with industrial contractors, and universities. The beginning of Sandia`s involvement in developing fusion power was an outgrowth of its contributions to the nation`s nuclear weapon program. The Laboratories` work in the early 1960`s emphasized the use of pulsed radiation environments to test the resistance of US nuclear weapons to enemy nuclear bursts. A careful study of options for fusion power indicated that Sandia`s expertise in the pulsed power field could provide a powerful match to ignite fusion fuel. Although creating test environments is an achieved goal of Sandia`s overall program, this work and other military tasks protected by appropriate security regulations will continue, making full use of the same pulsed power technology and accelerators as the fusion-for-energy program. Major goals of Sandia`s fusion program including the following: (1) complete a particle accelerator to deliver sufficient beam energy for igniting fusion targets; (2) obtain net energy gain, this goal would provide fusion energy output in excess of energy stored in the accelerator; (3) develop a technology base for the repetitive ignition of pellets in a power reactor. After accomplishing these goals, the technology will be introduced to the nation`s commercial sector.

1980-12-31T23:59:59.000Z

17

Circular, confined distribution for charged particle beams  

DOE Patents (OSTI)

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

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

1995-11-21T23:59:59.000Z

18

Circular, confined distribution for charged particle beams  

DOE Patents (OSTI)

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

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

1995-01-01T23:59:59.000Z

19

Relativistic electron beam device  

DOE Patents (OSTI)

A design is given for an electron beam device for irradiating spherical hydrogen isotope bearing targets. The accelerator, which includes hollow cathodes facing each other, injects an anode plasma between the cathodes and produces an approximately 10 nanosecond, megajoule pulse between the anode plasma and the cathodes. Targets may be repetitively positioned within the plasma between the cathodes, and accelerator diode arrangement permits materials to survive operation in a fusion power source. (auth)

Freeman, J.R.; Poukey, J.W.; Shope, S.L.; Yonas, G.

1975-07-01T23:59:59.000Z

20

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

Science Conference Proceedings (OSTI)

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

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 fusion research facilities at Sandia National Laboratories  

SciTech Connect

Sandia research in inertial-confinement fusion (ICF) is based on pulse-power capabilities that grew out of earlier developments of intense relativistic electron-beam (e-beam) radiation sources for weapon effects studies. ICF involves irradiating a deuterium-tritium pellet with either laser light or particle beams until the center of the pellet is compressed and heated to the point of nuclear fusion. This publication focuses on the use of particle beams to achieve fusion, and on the various facilities that are used in support of the particle-beam fusion (PBF) program.

1980-12-31T23:59:59.000Z

22

Electron Beam Melting (EBM) II  

Science Conference Proceedings (OSTI)

Oct 19, 2011 ... Additive Manufacturing of Metals: Electron Beam Melting (EBM) II Sponsored by: MS&T Organization Program Organizers: Ian D. Harris, EWI; ...

23

Low Emittance Electron Beam Studies  

Science Conference Proceedings (OSTI)

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

24

PLASMA WAKE EXCITATION BY LASERS OR PARTICLE BEAMS  

SciTech Connect

Plasma accelerators may be driven by the ponderomotive force of an intense laser or the space-charge force of a charged particle beam. Plasma wake excitation driven by lasers or particle beams is examined, and the implications of the different physical excitation mechanisms for accelerator design are discussed. Plasma-based accelerators have attracted considerable attention owing to the ultrahigh field gradients sustainable in a plasma wave, enabling compact accelerators. These relativistic plasma waves are excited by displacing electrons in a neutral plasma. Two basic mechanisms for excitation of plasma waves are actively being researched: (i) excitation by the nonlinear ponderomotive force (radiation pressure) of an intense laser or (ii) excitation by the space-charge force of a dense charged particle beam. There has been significant recent experimental success using lasers and particle beam drivers for plasma acceleration. In particular, for laser-plasma accelerators (LPAs), the demonstration at LBNL in 2006 of high-quality, 1 GeV electron beams produced in approximately 3 cm plasma using a 40 TW laser. In 2007, for beam-driven plasma accelerators, or plasma-wakefield accelerators (PWFAs), the energy doubling over a meter to 42 GeV of a fraction of beam electrons on the tail of an electron beam by the plasma wave excited by the head was demonstrated at SLAC. These experimental successes have resulted in further interest in the development of plasma-based acceleration as a basis for a linear collider, and preliminary collider designs using laser drivers and beam drivers are being developed. The different physical mechanisms of plasma wave excitation, as well as the typical characteristics of the drivers, have implications for accelerator design. In the following, we identify the similarities and differences between wave excitation by lasers and particle beams. The field structure of the plasma wave driven by lasers or particle beams is discussed, as well as the regimes of operation (linear and nonlinear wave). Limitations owing to driver emittance are also discussed.

Schroeder, Carl B.; Esarey, Eric; Benedetti, Carlo; Toth, Csaba; Geddes, Cameron; Leemans, Wim

2011-04-01T23:59:59.000Z

25

Repetitively pumped electron beam device  

DOE Patents (OSTI)

Disclosed is an apparatus for producing fast, repetitive pulses of controllable length of an electron beam by phased energy storage in a transmission line of length matched to the number of pulses and specific pulse lengths desired. 12 figs.

Schlitt, L.G.

1979-07-24T23:59:59.000Z

26

Repetitively pumped electron beam device  

DOE Patents (OSTI)

Apparatus for producing fast, repetitive pulses of controllable length of an electron beam by phased energy storage in a transmission line of length matched to the number of pulses and specific pulse lengths desired.

Schlitt, Leland G. (Livermore, CA)

1979-01-01T23:59:59.000Z

27

NIST SURF: Beamline 10: Electron beam imaging  

Science Conference Proceedings (OSTI)

Beamline 10: Electron beam imaging. Description: ... In its unperturbed state, the vertical electron beam size is quite small, in the order of a few 10 ”m. ...

2012-11-19T23:59:59.000Z

28

Frontiers of Particle Beam Physics  

E-Print Network (OSTI)

Low Emittance e--e+ Beams, Brookhaven National Laboratory,Island, NY, October 1988, Brookhaven National Laboratory,Low Emittance e--e+ Beams, Brookhaven National Laboratory,

Sessler, Andrew M.

2008-01-01T23:59:59.000Z

29

Confined energy distribution for charged particle beams  

SciTech Connect

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

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

1990-01-01T23:59:59.000Z

30

Electron-Beam Irradiation of Solar Cells  

Science Conference Proceedings (OSTI)

Electron-Beam Irradiation of Solar Cells. Summary: The Dosimetry Group operates a system capable of performing electron ...

2013-02-27T23:59:59.000Z

31

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

32

Beam Characterizations at Femtosecond Electron Beam Facility  

SciTech Connect

The SURIYA project at the Fast Neutron Research Facility (FNRF) has been established and is being commissioning to generate femtosecond (fs) electron bunches. Theses short bunches are produced by a system consisting of an S-band thermionic cathode RF-gun, an alpha magnet (a-magnet) serving as a magnetic bunch compressor, and a SLAC-type linear accelerator (linac). The characteristics of its major components and the beam characterizations as well as the preliminary experimental results will be presented and discussed in this paper.

Rimjaem, S.; Jinamoon, V.; Kangrang, M.; Kusoljariyakul, K.; Saisut, J.; Thongbai, C.; Vilaithong, T.; Rhodes, M.W.; Wichaisirimongkol, P.; /Chiang Mai U.; Wiedemann, H.; /SLAC

2006-03-17T23:59:59.000Z

33

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. 2 figs.

Mochel, M.E.; Humphreys, C.J.

1985-04-02T23:59:59.000Z

34

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

35

Shimmed electron beam welding process  

DOE Patents (OSTI)

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

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

2002-01-01T23:59:59.000Z

36

Electron beam dynamics for the ISIS bremsstrahlung beam generation system  

E-Print Network (OSTI)

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

Block, Robert E. (Robert Edward)

2011-01-01T23:59:59.000Z

37

Collected abstracts on particle beam diagnostic systems  

SciTech Connect

This report contains a compilation of abstracts on work related to particle beam diagnostics for high temperature plasmas. The abstracts were gathered in early 1978 and represent the status of the various programs as of that date. It is not suggested that this is a comprehensive list of all the work that is going on in the development of particle beam diagnostics, but it does provide a representative view of the work in this field. For example, no abstracts were received from the U.S.S.R. even though they have considerable activity in particle beam diagnostics.

Hickok, R.L.

1979-01-01T23:59:59.000Z

38

Light modulated electron beam driven radiofrequency emitter  

DOE Patents (OSTI)

The disclosure relates to a light modulated electron beam-driven radiofrequency emitter. Pulses of light impinge on a photoemissive device which generates an electron beam having the pulse characteristics of the light. The electron beam is accelerated through a radiofrequency resonator which produces radiofrequency emission in accordance with the electron, hence, the light pulses.

Wilson, M.T.; Tallerico, P.J.

1979-10-10T23:59:59.000Z

39

INSTABILITIES OF RELATIVISTIC PARTICLE BEAMS  

E-Print Network (OSTI)

1965). K. W. Robinson, in SLAC Storage Ring Stumner Study,Beams, a Summary. Report, SLAC-49, L. J. Laslett, V. K.La.slett and A. M. Sessler, in SLAC-49, Sept. 1965 (see Ref.

Sessler, Andrew M.

2008-01-01T23:59:59.000Z

40

Use of an Electron Beam for Stochastic Cooling  

Science Conference Proceedings (OSTI)

Microwave instability of an electron beam can be used for a multiple increase in the collective response for the perturbation caused by a particle of a co-moving ion beam, i.e. for enhancement of friction force in electron cooling method. The low scale (hundreds GHz and higher frequency range) space charge or FEL type instabilities can be produced (depending on conditions) by introducing an alternating magnetic fields along the electron beam path. Beams’ optics and noise conditioning for obtaining a maximal cooling effect and related limitations will be discussed. The method promises to increase by a few orders of magnitude the cooling rate for heavy particle beams with a large emittance for a wide energy range with respect to either electron and conventional stochastic cooling.

Yaroslave Derbenev

2007-09-10T23:59:59.000Z

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.


41

APPARATUS FOR ELECTRON BEAM HEATING CONTROL  

DOE Patents (OSTI)

An improved electron beam welding or melting apparatus is designed which utilizes a high voltage rectifier operating below its temperature saturation region to decrease variations in electron beam current which normally result from the gas generated in such apparatus. (AEC)

Jones, W.H.; Reece, J.B.

1962-09-18T23:59:59.000Z

42

Chirping the LCLS Electron Beam  

E-Print Network (OSTI)

We explore scenarios for generating a linear time-correlated energy spread in the LCLS electron bunch, prior to the undulator, that is needed for optical (x-ray) pulse compression. The correlated energy spread (`chirp') is formed by generating an energy gradient along the length of the electron bunch using RF phasing and/or longitudinal wakefields of the accelerating structures. The sign of the correlation is an important limitation. Excluding a complete re-design of the compression systems, the best possibility is to use `over-compression' to effect the required energy chirp. This is easily done with only a slight strength increase (~10 %) in the chicane bends of the second compressor. In this case, the bend-plane emittance dilution associated with the increased coherent synchrotron radiation (CSR) in the bunch compressor may, however, significantly compromise the electron beam density. The CSR calculations for the momentary extremely short (~1 m) electron bunch during over-compressio...

P. Emma

2000-01-01T23:59:59.000Z

43

LOW ENERGY BEAM PROCESSES IN ELECTRONIC MATERIALS ...  

Science Conference Proceedings (OSTI)

LOW ENERGY BEAM PROCESSES IN ELECTRONIC MATERIALS: Session II: Shallow Junction and Low Energy Implantation. Sponsored by: EMPMD Thin ...

44

Electron Beam Melting: The New Directional Solidification  

Science Conference Proceedings (OSTI)

About this Abstract. Meeting, Materials Science & Technology 2011. Symposium, Additive Manufacturing of Metals. Presentation Title, Electron Beam Melting: ...

45

Electron Beam Ion Trap (EBIT) Facility  

Science Conference Proceedings (OSTI)

... At these temperatures, even the heaviest atoms shed most of their electrons. ... The ions are probed with an intense electron beam, and the emitted ...

2013-06-06T23:59:59.000Z

46

Particle beam generator using a radioactive source  

DOE Patents (OSTI)

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

Underwood, D.G.

1991-12-31T23:59:59.000Z

47

Particle beam generator using a radioactive source  

DOE Patents (OSTI)

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

Underwood, D.G.

1993-03-30T23:59:59.000Z

48

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

49

Beam/seam alignment control for electron beam welding  

DOE Patents (OSTI)

This invention relates to a dynamic beam/seam alignment control system for electron beam welds utilizing video apparatus. The system includes automatic control of workpiece illumination, near infrared illumination of the workpiece to limit the range of illumination and camera sensitivity adjustment, curve fitting of seam position data to obtain an accurate measure of beam/seam alignment, and automatic beam detection and calculation of the threshold beam level from the peak beam level of the preceding video line to locate the beam or seam edges.

Burkhardt, Jr., James H. (Knoxville, TN); Henry, J. James (Oak Ridge, TN); Davenport, Clyde M. (Knoxville, TN)

1980-01-01T23:59:59.000Z

50

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

51

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

52

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 T{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.

1998-04-21T23:59:59.000Z

53

Dependence of the Photon Beam Characteristics on Electron Beam Parameters in Third Generation Synchrotron Light Sources  

E-Print Network (OSTI)

Dependence of the Photon Beam Characteristics on Electron Beam Parameters in Third Generation Synchrotron Light Sources

Ivanyan, M I; Tsakanov, V M

2002-01-01T23:59:59.000Z

54

Towards demonstration of electron cooling with bunched electron beam  

SciTech Connect

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

Fedotov, A.

2012-01-11T23:59:59.000Z

55

Frequency multiplying oscillator with an electron beam accelerated in a drift space  

Science Conference Proceedings (OSTI)

In a uniform acceleration region, the behavior of a velocity-modulated electron beam has been analyzed using a particle-in-cell code. By making use of one of the accelerated harmonic components of the velocity-modulated electron beam, we demonstrate a frequency multiplying oscillator for a compact THz emitter, which employs multiple electron beams and a higher order mode resonator to modulate the electron beam without an additional driving source.

Jang, Kyu-Ha; Lee, Kitae; Hee Park, Seong; Uk Jeong, Young [WCI Center for Quantum Beam-based Radiation Research, Korea Atomic Energy Research Institute, 1045 Deadeok, Yuseong, Daejeon 305-353 (Korea, Republic of); Miginsky, S. [WCI Center for Quantum Beam-based Radiation Research, Korea Atomic Energy Research Institute, 1045 Deadeok, Yuseong, Daejeon 305-353 (Korea, Republic of); Budker Institute of Nuclear Physics, SB RAS, Academician Lavrentyev St. 11, Novosibrisk (Russian Federation)

2012-07-02T23:59:59.000Z

56

Electron Beam Imaging - Programmaster.org  

Science Conference Proceedings (OSTI)

Sep 14, 2009 ... 13th International Conference on Defects--Recognition, Imaging and Physics in Semiconductors: Electron Beam Imaging Program Organizers: ...

57

Produced by Selective Electron Beam Melting  

Science Conference Proceedings (OSTI)

The development of processing TiAl by additive manufacturing by using the selective electron beam melting (SEBM) provides a new approach to reach near

58

Particle beam fusion research at Sandia National Laboratories  

SciTech Connect

Sandia`s Particle Beam Fusion Program is investigating several driver options, based on pulsed power technology, with the goal of demonstrating a practical ignitor for Inertial Confinement Fusion (ICF) Reactors. The interrelated aspects of power conditioning and compression, beam-target interaction, and target ignition are being studied. The issues of efficiency, reliability and multiple pulse capability are being integrated into the program to provide a viable approach to an experimental power reactor. On a shorter time scale the authors expect to derive important military-related benefits from attendant research and facility development. The two most important advantages of pulsed power driven fusion are the inherent low cost and high efficiency of high current particle accelerators. However, comparison of the relative merits of particle beams and focused laser beams must include many other factors such as beam transport, and target coupling, as well as target design and fabrication. These issues are being investigated to determine if the perceived practical benefits of particle beam fusion can indeed be realized. The practical considerations are exemplified in a comparison of the leading ICF drivers. The plan being followed by Sandia involves using the Electron Beam Fusion Accelerator (EBFA) to meet three objectives by 1985: significant burn using EBFA 1, net energy gain based on an upgrade of EBFA to the 2 megajoule (MJ) level (EBFA 2), and demonstration of a single module of EBFA 2 operated in the repetitive pulse mode. These goals are dependent, of course, on success in solving several key technical problems under investigation. If these technical problems can be solved, then practical applications to fusion power could be considered. The potential for these applications has been studied using economic models that allow one to derive the cost of power based on various assumptions.

1978-12-31T23:59:59.000Z

59

Precision Absolute Beam Current Measurement of Low Power Electron Beam  

SciTech Connect

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

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

2012-11-01T23:59:59.000Z

60

Feasibility study for mega-electron-volt electron beam tomography  

SciTech Connect

Electron beam tomography is a promising imaging modality for the study of fast technical processes. But for many technical objects of interest x rays of several hundreds of keV energy are required to achieve sufficient material penetration. In this article we report on a feasibility study for fast electron beam computed tomography with a 1 MeV electron beam. The experimental setup comprises an electrostatic accelerator with beam optics, transmission target, and a single x-ray detector. We employed an inverse fan-beam tomography approach with radiographic projections being generated from the linearly moving x-ray source. Angular projections were obtained by rotating the object.

Hampel, U. [Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden (Germany); AREVA Endowed Chair of Imaging Techniques in Energy and Process Engineering, Technische Universitaet Dresden, 01062 Dresden (Germany); Baertling, Y.; Hoppe, D. [Institute of Fluid Dynamics, Helmholtz-Zentrum Dresden-Rossendorf, Bautzner Landstrasse 400, 01328 Dresden (Germany); Kuksanov, N.; Fadeev, S.; Salimov, R. [Budker Institute of Nuclear Physics of Siberian Branch of Russian Academy of Science, Lavrentiev av. 11, Novosibirsk 630090 (Russian Federation)

2012-09-15T23:59:59.000Z

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.


61

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

Science Conference Proceedings (OSTI)

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

62

Influence of electron beam parameters on coherent electron cooling  

Science Conference Proceedings (OSTI)

Coherent electron cooling (CeC) promises to revolutionize the cooling of high energy hadron beams. The intricate dynamics of the CeC depends both on the local density and energy distribution of the beam. The variations of the local density (beam current) are inevitable in any realistic beam. Hence, in this paper we propose a novel method of beam conditioning. The conditioning provides compensation of effect from such variation by a correlated energy modulation. We use our analytical FEL model for an electron bunch with Gaussian line charge density and cosine-type energy variation along bunch. We analyze the phase variation between the electron density modulation at the exit of the FEL-amplifier and the ions inducing it in the modulator as a function of the peak current and the electron beam energy. Based on this analysis, electron bunch parameters for optimal CeC cooling are found numerically.

Wang G.; Hao, Y.; Litvinenko, V.N.; Webb, S.

2012-05-20T23:59:59.000Z

63

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. 2 figs.

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

1990-07-17T23:59:59.000Z

64

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

65

Electron acceleration during three-dimensional relaxation of an electron beam-return current plasma system in a magnetic field  

E-Print Network (OSTI)

We investigate the effects of acceleration during non-linear electron-beam relaxation in magnetized plasma in the case of electron transport in solar flares. The evolution of electron distribution functions is computed using a three-dimensional particle-in-cell electromagnetic code. Analytical estimations under simplified assumptions are made to provide comparisons. We show that, during the non-linear evolution of the beam-plasma system, the accelerated electron population appears. We found that, although the electron beam loses its energy efficiently to the thermal plasma, a noticeable part of the electron population is accelerated. For model cases with initially monoenergetic beams in uniform plasma, we found that the amount of energy in the accelerated electrons above the injected beam-electron energy varies depending the plasma conditions and could be around 10-30% of the initial beam energy. This type of acceleration could be important for the interpretation of non-thermal electron populations in solar f...

Karlicky, M

2012-01-01T23:59:59.000Z

66

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

67

Electron beam depolarization in a damping ring  

SciTech Connect

Depolarization of a polarized electron beam injected into a damping ring is analyzed by extending calculations conventionally applied to proton synchrotrons. Synchrotron radiation in an electron ring gives rise to both polarizing and depolarizing effects. In a damping ring, the beam is stored for a time much less than the time for self polarization. Spin flip radiation may therefore be neglected. Synchrotron radiation without spin flips, however, must be considered as the resonance strength depends on the vertical betatron oscillation amplitude which changes as the electron beam is radiation damped. An expression for the beam polarization at extraction is derived which takes into account radiation damping. The results are applied to the electron ring at the Stanford Linear Collider and are compared with numerical matrix formalisms.

Minty, M.

1993-04-01T23:59:59.000Z

68

Emittance growth from electron beam modulation  

SciTech Connect

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

Blaskiewicz, M.

2009-12-01T23:59:59.000Z

69

Transient Melt Pool Response in Wire Feed Electron Beam Direct ...  

Science Conference Proceedings (OSTI)

Presentation Title, Transient Melt Pool Response in Wire Feed Electron Beam Direct ... Abstract Scope, Wire feed electron beam direct digital manufacturing ...

70

NIST Puts a New Twist on the Electron Beam  

Science Conference Proceedings (OSTI)

... This method produces several electron beams fanning out in different directions, with each beam made of electrons that orbit around the direction ...

2011-01-19T23:59:59.000Z

71

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

72

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

E-Print Network (OSTI)

Society's growing demands for energy results in rapid increase in oil consumption and motivates us to make unconventional resources conventional resources. There are enormous amounts of heavy oil reserves in the world but the lack of cost effective technologies either for extraction, transportation, or refinery upgrading hinders the development of heavy oil reserves. One of the critical problems with heavy oil and bitumen is that they require large amounts of thermal energy and expensive catalysts to upgrade. This thesis demonstrates that electron beam (E-Beam) heavy oil upgrading, which uses unique features of E-Beam irradiation, may be used to improve conventional heavy oil upgrading. E-Beam processing lowers the thermal energy requirements and could sharply reduce the investment in catalysts. The design of the facilities can be simpler and will contribute to lowering the costs of transporting and processing heavy oil and bitumen. E-Beam technology uses the high kinetic energy of fast electrons, which not only transfer their energy but also interact with hydrocarbons to break the heavy molecules with lower thermal energy. In this work, we conducted three major stages to evaluate the applicability of E-Beam for heavy oil upgrading. First, we conducted laboratory experiments to investigate the effects of E-Beam on hydrocarbons. To do so, we used a Van de Graff accelerator, which generates the high kinetic energy of electrons, and a laboratory scale apparatus to investigate extensively how radiation effects hydrocarbons. Second, we studied the energy transfer mechanism of E-Beam upgrading to optimize the process. Third, we conducted a preliminary economic analysis based on energy consumption and compared the economics of E-Beam upgrading with conventional upgrading. The results of our study are very encouraging. From the experiments we found that E-Beam effect on hydrocarbon is significant. We used less thermal energy for distillation of n-hexadecane (n-C16) and naphtha with E-Beam. The results of experiments with asphaltene indicate that E-Beam enhances the decomposition of heavy hydrocarbon molecules and improves the quality of upgraded hydrocarbon. From the study of energy transfer mechanism, we estimated heat loss, fluid movement, and radiation energy distribution during the reaction. The results of our economic evaluation show that E-Beam upgrading appears to be economically feasible in petroleum industry applications. These results indicate significant potential for the application of E-Beam technology throughout the petroleum industry, particularly near production facilities, transportation pipelines, and refining industry.

Yang, Daegil

2009-12-01T23:59:59.000Z

73

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

74

Short rise time intense electron beam generator  

DOE Patents (OSTI)

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

Olson, Craig L. (Albuquerque, NM)

1987-01-01T23:59:59.000Z

75

Relativistic electron beam plasma heating experiment  

SciTech Connect

An intense (5 x 10/sup 5/ Amp/cm/sup 2/), relativistic (5 MeV), electron beam will be used to investigate the heating of small volumes (approx. 5 to 10 cm/sup 3/) of dense plasma (10/sup 17/ to 10/sup 18/ electrons/cm/sup 3/) to kilovolt temperatures via the electrostatic two-stream instability.

Montgomery, M.D.; Parker, J.V.

1980-04-01T23:59:59.000Z

76

Study of various photomultiplier tubes with muon beams and Cerenkov light produced in electron showers  

E-Print Network (OSTI)

Study of various photomultiplier tubes with muon beams and Cerenkov light produced in electron beams and Cerenkov light produced in electron showers CMS HCAL collaboration E-mail: Burak their windows were traversed by energetic charged particles. This signal, which is due to Cerenkov light

Akgun, Ugur

77

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

E-Print Network (OSTI)

and by cold material in light of the recent proposals to employ particle beams for various fusion applications; ACCEPTED 23 May 2007) Abstract Scattering of energetic electron and proton beams by cold matter these results to the corresponding cold material. The more relevant case of electron scattering from partially

78

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

79

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

80

Electron Beam Polarization Measurement Using Touschek Lifetime Technique  

SciTech Connect

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

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

2012-08-24T23:59:59.000Z

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

MULTIPLE ELECTRON BEAM ION PUMP AND SOURCE  

DOE Patents (OSTI)

A vacuum pump is designed which operates by ionizing incoming air and by withdrawing the ions from the system by means of electrical fields. The apparatus comprises a cylindrical housing communicable with the vessel to be evacuated and having a thin wall section in one end. Suitable coils provide a longitudinal magnetic field within the cylinder. A broad cathode and an anode structure is provided to establish a plurality of adjacent electron beams which are parallel to the cylinder axis. Electron reflector means are provided so that each of the beams constitutes a PIG or reflex discharge. Such structure provides a large region in which incoming gas molecules may be ionized by electron bombardment. A charged electrode assembly accelerates the ions through the thin window, thereby removing the gas from the system. The invention may also be utilized as a highly efficient ion source. (AEC)

Ellis, R.E.

1962-02-27T23:59:59.000Z

82

Particle beam fusion progress report for 1989  

Science Conference Proceedings (OSTI)

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

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

1994-08-01T23:59:59.000Z

83

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-

84

Simulation of Hollow Electron Beam Collimation in the Fermilab Tevatron Collider  

Science Conference Proceedings (OSTI)

The concept of augmenting the conventional collimation system of high-energy storage rings with a hollow electron beam was successfully demonstrated in experiments at the Tevatron. A reliable numerical model is required for understanding particle dynamics in the presence of a hollow beam collimator. Several models were developed to describe imperfections of the electron beam profile and alignment. The features of the imperfections are estimated from electron beam profile measurements. Numerical simulations of halo removal rates are compared with experimental data taken at the Tevatron.

Morozov, I.A.; Stancari, G.; Valishev, A.; /Fermilab; Shatilov, D.N.; /Novosibirsk, IYF

2012-05-01T23:59:59.000Z

85

Two-beam detuned-cavity electron accelerator structure  

SciTech Connect

Progress has been made in the theory, development, cavity design and optimization, beam dynamics study, beam transport design, and hardware construction for studies of a detuned two-beam electron accelerator structure.

Jiang, Y.; Hirshfield, J. L. [Beam Physics Laboratory, Yale University, New Haven, CT 06511 (United States); Beam Physics Laboratory, Yale University, New Haven, CT 06511 (United States) and Omega-P, Inc., New Haven, CT 06510 (United States)

2012-12-21T23:59:59.000Z

86

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

87

Tuning of Graphene Properties via Controlled Exposure to Electron Beams  

Science Conference Proceedings (OSTI)

The controlled modification of graphene properties is essential for its proposed electronic applications. Here, we describe a possibility of tuning electrical properties of graphene via electron-beam (e-beam) irradiation. We show that by controlling ...

Guanxiong Liu; D. Teweldebrhan; A. A. Balandin

2011-07-01T23:59:59.000Z

88

Performance of Advanced Light Source particle beam diagnostics  

SciTech Connect

The Advanced Light Source (ALS), a third-generation synchrotron radiation facility, is complete. The particle beam diagnostics have been installed and tested. The beam injection systems have been running for two years. We have performance data on beam position monitors, beam intensity monitors, scintillators, beam collimators, a 50 {Omega} Faraday cup, and broad-band striplines and kickers used in the linac, transport lines, and the booster synchrotron. The single-turn monitoring capability of the booster beam position monitoring system has been particularly useful for studying beam dynamics. Beam diagnostics for the storage ring are being commissioned. In this paper we describe each instrument, show its performance, and outline how the instruments are controlled and their output data displayed.

Hinkson, J.

1993-05-01T23:59:59.000Z

89

Electron Beam Cold Hearth Refinement Processing of Inconel Alloy ...  

Science Conference Proceedings (OSTI)

ELECTRON BEAM COLD HEARTH REFINEMENT PROCESSING OF. INCONEL" ALLOY 718 AND NIMONIC* ALLOY PK50. S. Patel+,. 1-C. Elliott+,.

90

Ionized channel generation of an intense-relativistic electron beam  

DOE Patents (OSTI)

A foilless intense relativistic electron beam generator uses an ionized cnel to guide electrons from a cathode passed an anode to a remote location.

Frost, Charles A. (Albuquerque, NM); Leifeste, Gordon T. (Albuquerque, NM); Shope, Steven L. (Albuquerque, NM)

1988-01-01T23:59:59.000Z

91

Multiple Electron Stripping of Heavy Ion Beams  

DOE Green Energy (OSTI)

One approach being explored as a route to practical fusion energy uses heavy ion beams focused on an indirect drive target. 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. Accelerators designed primarily for nuclear physics or high energy physics experiments utilize ion sources that generate highly stripped ions in order to achieve high energies economically. As a result, accelerators capable of producing heavy ion beams of 10 to 40 Mev/amu with charge state 1 currently do not exist. Hence, the stripping cross-sections used to model the performance of heavy ion fusion driver beams have, up to now, been based upon theoretical calculations. We have investigated experimentally the stripping of 3.4 Mev/amu Kr 7+ and Xe +11 in N2; 10.2 MeV/amu Ar +6 in He, N2, Ar and Xe; 19 MeV/amu Ar +8 in He, N2, Ar and Xe; 30 MeV He 1 + in He, N2, Ar and Xe; and 38 MeV/amu N +6 in He, N2, Ar and Xe. The results of these measurements are compared with the theoretical calculations to assess their applicability over a wide range of parameters.

D. Mueller; L. Grisham; I. Kaganovich; R. L. Watson; V. Horvat; K. E. Zaharakis; Y. Peng

2002-06-25T23:59:59.000Z

92

Nature of the beam-density effect on energy loss by nonrelativistic charged-particle beams  

DOE Green Energy (OSTI)

The authors present a new formulation of the beam-density effect on energy loss by charged particles passing through matter, which exhibits an increased loss with a beam-shape dependence. This arises from a long-range dipolelike term contained in the two-particle vicinage function for cooperative energy loss by a pair of nonrelativistic particles. A new analytic expression for the vicinage function, which exhibits the long-range term, is also presented.

Rule, D.W.; Crawford, O.H.

1984-03-12T23:59:59.000Z

93

Particle beam and crabbing and deflecting structure  

DOE Patents (OSTI)

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

Delayen, Jean (Yorktown, VA)

2011-02-08T23:59:59.000Z

94

Electrostatic quadrupole focused particle accelerating assembly with laminar flow beam  

DOE Patents (OSTI)

A charged particle accelerating assembly provided with a predetermined ratio of parametric structural characteristics and with related operating voltages applied to each of its linearly spaced focusing and accelerating quadrupoles, thereby to maintain a particle beam traversing the electrostatic fields of the quadrupoles in the assembly in an essentially laminar flow through the assembly.

Maschke, A.W.

1984-04-16T23:59:59.000Z

95

Designing a beam transport system for RHIC's electron lens  

SciTech Connect

We designed two electron lenses to apply head-on beam-beam compensation for RHIC; they will be installed near IP10. The electron-beam transport system is an important subsystem of the entire electron-lens system. Electrons are transported from the electron gun to the main solenoid and further to the collector. The system must allow for changes of the electron beam size inside the superconducting magnet, and for changes of the electron position by 5 mm in the horizontal- and vertical-planes.

Gu, X.; Pikin, A.; Okamura, M.; Fischer, W.; Luo, Y.; Gupta, R.; Hock, J.; Raparia, D.

2011-03-28T23:59:59.000Z

96

HIGH-INTENSITY EFFECTS IN THE LONGITUDINAL MOTION OF STORED PARTICLE BEAMS  

SciTech Connect

A brief review is given of the various self-field phenomena associated with the longitudinal motion of particles in storage rings. Although there are some high-intensity phenomena for which the coupling of longitudinal and transverse motion is essential, such as, for example, the headtail effect; the great majority of high-intensity phenomena primarily involve either longitudinal or transverse degrees of freedom. In this review, we restrict our attention to phenomena which are essentially longitudinal in nature. It is convenient to consider separately the behavior of unbunched (coasting) and bunched (external RF system in operation) beams. Detailed experimental information on coasting beams has been obtained on the ISR, on the (old) CERN electron model CESAR, and on electron ring accelerators. All high-energy electron storage rings have bunched beams and, of course, so do synchrotrons, so that there are a large number of sources of experimental information about the longitudinal motion of bunched beams.

Sessler, Andrew M.

1973-02-01T23:59:59.000Z

97

Electronically shielded solid state charged particle detector  

DOE Patents (OSTI)

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

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

1995-12-31T23:59:59.000Z

98

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

99

Beam conditioner for free electron lasers and synchrotrons  

DOE Patents (OSTI)

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

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

1998-01-01T23:59:59.000Z

100

PURIFICATION OF IRIDIUM BY ELECTRON BEAM MELTING  

Science Conference Proceedings (OSTI)

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

Ohriner, Evan Keith [ORNL

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.


101

Microradiography of electron beam braze joins  

SciTech Connect

Microradiography was used as one phase of a nondestructive evaluation program for inspection of the electron beam braze joining of dissimilar metals. Stainless steel tubing was joined to a gold-copper disk using a Cusil (copper/silver) brazing alloy. A 150-kV x-ray source was used with the radiographs recorded on high-resolution plates. Interpretation of the radiographs was aided by computer graphics displays of digitized film density measurements. Braze intrusion maps were generated indicating the extent of braze penetration into the stainless steel tube. Penetration as small as a few micrometers was observable.

Shackelford, J.F.

1980-07-24T23:59:59.000Z

102

Pseudo Slice Energy Spread in Dynamics of Electron Beams Moving through Magnetic Bends  

E-Print Network (OSTI)

In the previous canonical formulation of beam dynamics for an electron bunch moving ultrarelativistically through magnetic bending systems, we have shown that the transverse dynamics equation for a particle in the bunch has a driving term which behaves as the centrifugal force caused by the particle's initial potential energy due to collective particle interactions within the bunch. As a result, the initial potential energy at the entrance of a bending system, which we call pseudo (kinetic) energy, is indistinguishable from the usual kinetic energy offset from the design energy in its perturbation to particle optics through dispersion and momentum compaction. In this paper, in identifying this centrifugal force on particles as the remnant of the CSR cancellation effect in transverse particle dynamics, we show how the dynamics equation in terms of the canonical momentum for beam motion on a curved orbit is related to the Panofsky-Wenzel theorem for wakefields for beam motion on a straight path. It is shown tha...

Li, Rui

2014-01-01T23:59:59.000Z

103

Study of electron beam production by a plasma focus  

SciTech Connect

A preliminary investigation of the electron beam produced by a plasma focus device using a current charged transmission line is described. Electron beam currents as high as 10 kA were measured. Interaction of the extracted beam and the filling gas was studied using open shutter photography.

Smith, J.R.; Luo, C.M.; Rhee, M.J.; Schneider, R.F.

1983-01-01T23:59:59.000Z

104

Development of beam-plasma instability during the injection a low-energy electron beam into the ionospheric plasma  

SciTech Connect

Results are presented from an active experiment on the injection of charged particle beams into the ionospheric plasma. The experiment was carried out in 1992 onboard the Intercosmos-25 satellite and the Magion-3 daughter satellite (APEX). A specific feature of this experiment was that both the ion and electron beams were injected upward, in the same direction along the magnetic field. The most interesting results are the excitation of HF and VLF-LF waves and the generation of fast charged particle flows, which were recorded on both satellites.

Baranets, N. V.; Sobolev, Ya. P. [Russian Academy of Sciences, Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation (Russian Federation); Ciobanu, M. [Institute for Gravitation and Space Sciences (Romania); Vojta, J.; Smilauer, J. [Academy of Sciences of the Czech Republic, Institute of Atmospheric Physics (Czech Republic); Klos, Z.; Rothkaehl, H.; Kiraga, A. [Polish Academy of Sciences, Space Research Center (Poland); Kudela, K.; Matisin, J. [Slovak Academy of Sciences, Institute of Experimental Physics (Slovakia); Afonin, V. V. [Russian Academy of Sciences, Space Research Institute (Russian Federation); Ryabov, B. S.; Isaev, N. V. [Russian Academy of Sciences, Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation (Russian Federation)

2007-12-15T23:59:59.000Z

105

High density harp or wire scanner for particle beam diagnostics  

DOE Patents (OSTI)

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

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

1996-05-21T23:59:59.000Z

106

Nonlinear transmission line based electron beam driver  

Science Conference Proceedings (OSTI)

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

107

ABSTRACT: Ion-Induced Damage Accumulation and Electron-Beam ...  

Science Conference Proceedings (OSTI)

Jun 27, 2007... Ion-Induced Damage Accumulation and Electron-Beam-Enhanced ... damage accumulation in strontium titanate from 1.0 MeV Au irradiation

108

Electron beam accelerator with magnetic pulse compression and accelerator switching  

DOE Patents (OSTI)

An electron beam accelerator comprising an electron beam generator-injector to produce a focused beam of .gtoreq.0.1 MeV energy electrons; a plurality of substantially identical, aligned accelerator modules to sequentially receive and increase the kinetic energies of the beam electrons by about 0.1-1 MeV per module. Each accelerator module includes a pulse-forming network that delivers a voltage pulse to the module of substantially 0.1-1 MeV maximum energy over a time duration of .ltoreq.1 .mu.sec.

Birx, Daniel L. (Brentwood, CA); Reginato, Louis L. (Orinda, CA)

1987-01-01T23:59:59.000Z

109

Electron beam accelerator with magnetic pulse compression and accelerator switching  

DOE Patents (OSTI)

An electron beam accelerator comprising an electron beam generator-injector to produce a focused beam of .gtoreq.0.1 MeV energy electrons; a plurality of substantially identical, aligned accelerator modules to sequentially receive and increase the kinetic energies of the beam electrons by about 0.1-1 MeV per module. Each accelerator module includes a pulse-forming network that delivers a voltage pulse to the module of substantially .gtoreq.0.1-1 MeV maximum energy over a time duration of .ltoreq.1 .mu.sec.

Birx, Daniel L. (Brentwood, CA); Reginato, Louis L. (Orinda, CA)

1988-01-01T23:59:59.000Z

110

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 Researchers at the ALS have demonstrated a new method to generate tunable, coherent, broadband terahertz...

111

Electron Beam Evaporator Systems for Thin Film Deposition  

Science Conference Proceedings (OSTI)

The Thin Film and Nanostructure Processing Group has two high-vacuum, electron beam evaporator systems for fabrication of single and multilayer ...

2012-10-23T23:59:59.000Z

112

Electron Beam Cold Hearth Refining of Investment Casting ...  

Science Conference Proceedings (OSTI)

Electron Beam Cold Hearth Refining of Investment Casting Superalloys in a Large Production EB Furnace. Janine C. Borofka. Axe1 Johnson Metals, Inc.

113

Endoscopic Electron-Beam Cancer Therapy | Argonne National Laboratory  

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

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

114

Experimental Observation of Energy Modulation in Electron Beams...  

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

OBSERVATION OF ENERGY MODULATION IN ELECTRON BEAMS PASSING THROUGH TERAHERTZ DIELECTRIC WAKEFIELD STRUCTURES* S. Antipov , C. Jing, P. Schoessow, and A. Kanareykin, Euclid...

115

Process Modelling of Electron Beam Welding of Aeroengine ...  

Science Conference Proceedings (OSTI)

PROCESS MODELLING OF THE ELECTRON BEAM WELDING OF AEROENGINE COMPONENTS. R. C. Reed, H.J. Stone, D Dye and S.M. Roberts.

116

A Combined Crossed Molecular Beams and Electronic Structure Study...  

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

Combined Crossed Molecular Beams and Electronic Structure Study on the Gas Phase Formation of Prototype Aromatic and Polycyclic Aromatic Hydrocarbons (PAHs) Ralf I. Kaiser Dept....

117

Electron beam accelerator with magnetic pulse compression and accelerator switching  

DOE Patents (OSTI)

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

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

1984-03-22T23:59:59.000Z

118

Temperature distributions in electron beam welding cavities  

SciTech Connect

Surface temperatures in electron beam welding cavities in stainless steel 304 and aluminum 1100, 2024, and 6061 were measured with a narrow band infrared radiation pyrometer. A special device was designed for mounting the radiation-sensing probe next to the electron beam gun in the welding chamber. This mounting device included a mechanism for oscillating the probe so as to scan the cavity region both perpendicular and parallel to the welding direction. At the center of its movement the probe viewed almost directly down into the welding cavity. The effect of interreflections occurring in the welding cavity were accounted for by the use of an apparent spectral cavity emittance. Typical measured cavity temperature distributions for SS-304 ranged from 1950/sup 0/C at the mouth to a peak of 2350/sup 0/C at the cavity base and from 1300 to 1650/sup 0/C for A1-1100. First approximation predictions of the cavity surface temperatures were determined by assuming a quasi-steady-state condition. The surface temperature is then a function of the vapor pressure, which is required to balance the surface tension and the hydrostatic pressure both of which tend to collapse the cavity. Base temperatures thus predicted were about 5% and 10% higher than measured for SS-304 and A1-1100, respectively. It was determined that EB welding cavity base surface temperatures are relatively constant with varying penetration depth because they are more strongly dependent on the curvature at the base than on the penetration depth. Average peak temperatures for SS-304, A1-1100, A1-6061, and A1-2024 were measured to be approximately 2300, 1700, 1525, and 1475/sup 0/C, respectively. The peak temperatures were lower for A1-6061 and A1-2024 than for A1-1100 because they contained a significant amount of magnesium and zinc, both of which have comparatively high vapor pressures.

Shintaku, S.M.

1976-07-15T23:59:59.000Z

119

Electron-beam magnetic switch for a plurality of free-electron lasers  

DOE Patents (OSTI)

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

Schlitt, L.G.

1982-01-26T23:59:59.000Z

120

Electron beam magnetic switch for a plurality of free electron lasers  

DOE Patents (OSTI)

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

Schlitt, Leland G. (Livermore, CA)

1984-01-01T23:59:59.000Z

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.


121

Ionized channel generation of an intense relativistic electron beam  

DOE Patents (OSTI)

An intense relativistic electron beam generator uses an ionized channel to guide electrons from a cathode past an anode to a remote location without the use of a foil.

Frost, C.A.; Leifeste, G.T.; Shope, S.L.

1986-03-31T23:59:59.000Z

122

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

123

Density effect on relativistic electron beams in a plasma fiber  

Science Conference Proceedings (OSTI)

Intense short-petawatt-laser driven relativistic electron beams in a hollow high-Z plasma fiber embedded in low-Z plasmas of different densities are studied. When the plasma is of lower density than the hollow fiber, resistive filamentation of the electron beam is observed. It is found that the electron motion and the magnetic field are highly correlated with tens of terahertz oscillation frequency. Depending on the material property around the hollow fiber and the plasma density, the beam electrons can be focused or defocused as it propagates in the plasma. Relativistic electron transport and target heating are also investigated.

Zhou, C. T.; 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); Wang, X. G. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Wu, S. Z. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Cai, H. B. [Institute of Applied Physics and Computational Mathematics, Beijing 100094 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Wang, F. [Center for Applied Physics and Technology, Peking University, Beijing 100871 (China)

2010-11-15T23:59:59.000Z

124

Magnet Lattice Design for the Transmission of Power Using Particle Beams  

SciTech Connect

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

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

2012-08-24T23:59:59.000Z

125

Numerical simulation of the electron beam welding process  

Science Conference Proceedings (OSTI)

Electron beam welding is a highly efficient and precise welding method that is being increasingly used in industrial manufacturing and is of growing importance in industry. Compared to other welding processes it offers the advantage of very low heat ... Keywords: 3D conical heat source, Electron beam welding (EBW), Heat-affected zone, Numerical simulation, Thermomechanical coupling analysis

Piotr Lacki; Konrad Adamus

2011-06-01T23:59:59.000Z

126

Electron beam lithography using plasma polymerized hexane as resist  

Science Conference Proceedings (OSTI)

We present electron beam lithography using thin layers of plasma polymerized hexane as resist, as an alternative for conventional spincoated resists. Hexane is chosen due to the possible bioapplications, as well as the relatively simple polymerization ... Keywords: Electron beam lithography, Hexane, Plasma polymerization, Resist

R. H. Pedersen; M. Hamzah; S. Thoms; P. Roach; M. R. Alexander; N. Gadegaard

2010-05-01T23:59:59.000Z

127

NOx reduction by electron beam-produced nitrogen atom injection  

DOE Patents (OSTI)

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

Penetrante, Bernardino M. (San Ramon, CA)

2002-01-01T23:59:59.000Z

128

Interaction of relativistic electron beams with high Z plasmas  

SciTech Connect

A set of relativistic multigroup diffusion equations was derived for the study of electron beam--target interactions. Included are transport, Coulomb collisions, electric and magnetic fields, bremsstrahlung, and hydrodynamic motion of the background plasma. LASNEX, the Laser-Fusion code, is being modified to include these equations and will be used for modeling electron beam fusion. (auth)

Kershaw, D.S.

1975-10-27T23:59:59.000Z

129

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.

130

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.

131

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.

132

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.

133

Transient Self-Amplified Cerenkov Radiation with a Short Pulse Electron Beam  

SciTech Connect

An analytic and numerical examination of the slow wave Cerenkov free electron maser is presented. We consider the steady state amplifier configuration as well as operation in the selfamplified spontaneous emission (SASE) regime. The linear theory is extended to include electron beams that have a parabolic radial density inhomogeneity. Closed form solutions for the dispersion relation and modal structure of the electromagnetic field are determined in this inhomogeneous case. To determine the steady state response, a macro-particle approach is used to develop a set of coupled nonlinear ordinary differential equations for the amplitude and phase of the electromagnetic wave, which are solved in conjunction with the particle dynamical equations to determine the response when the system is driven as an amplifier with a time harmonic source. We then consider the case in which a fast rise time electron beam is injected into a dielectric loaded waveguide. In this case, radiation is generated by SASE, with the instability seeded by the leading edge of the electron beam. A pulse of radiation is produced, slipping behind the leading edge of the beam due to the disparity between the group velocity of the radiation and the beam velocity. Short pulses of microwave radiation are generated in the SASE regime and are investigated using particle-in-cell (PIC) simulations. The nonlinear dynamics are significantly more complicated in the transient SASE regime when compared with the steady state amplifier model due to the slippage of the radiation with respect to the beam. As strong self-bunching of the electron beam develops due to SASE, short pulses of superradiant emission develop with peak powers significantly larger than the predicted saturated power based on the steady state amplifier model. As these superradiant pulses grow, their pulse length decreases and forms a series of soliton-like pulses. Comparisons between the linear theory, macro-particle model, and PIC simulations are made in the appropriate regimes.

Poole, B R; Blackfield, D T; Camacho, J F

2009-01-22T23:59:59.000Z

134

Pulsed particle beam vacuum-to-air interface  

DOE Patents (OSTI)

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

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

1987-06-18T23:59:59.000Z

135

Transverse-structure electrostatic charged particle beam lens  

DOE Patents (OSTI)

Electrostatic particle-beam lenses using a concentric co-planar array of independently biased rings can be advantageous for some applications. Traditional electrostatic lenses often consist of axial series of biased rings, apertures, or tubes. The science of lens design has devoted much attention to finding axial arrangements that compensate for the substantial optical aberrations of the individual elements. Thus, as with multi-element lenses for light, a multi-element charged-particle lens can have optical behavior that is far superior to that of the individual elements. Transverse multiple-concentric-ring lenses achieve high performance, while also having advantages in terms of compactness and optical versatility. 7 figs.

Moran, M.J.

1998-10-13T23:59:59.000Z

136

Transverse-structure electrostatic charged particle beam lens  

DOE Patents (OSTI)

Electrostatic particle-beam lenses using a concentric co-planar array of independently biased rings can be advantageous for some applications. Traditional electrostatic lenses often consist of axial series of biased rings, apertures, or tubes. The science of lens design has devoted much attention to finding axial arrangements that compensate for the substantial optical aberrations of the individual elements. Thus, as with multi-element lenses for light, a multi-element charged-particle lens can have optical behavior that is far superior to that of the individual elements. Transverse multiple-concentric-ring lenses achieve high performance, while also having advantages in terms of compactness and optical versatility.

Moran, Michael J. (Pleasanton, CA)

1998-01-01T23:59:59.000Z

137

Physics of relativistic electron beams in rectangular and cylindrical geometries  

SciTech Connect

The use of electron beams for the direct pumping of lasers for fusion applications requires the generation of large area beams in appropriate geometries. Two geometries which are of particular interest are rectangular electron beams with planar anodes and radially converging beams with cyclindrical anodes. The generation of such beams requires the management of electron trajectories in a complex combination of applied and self-generated electric and magnetic fields. The beam's self-electric field limits the emitted current and the deflection of the electron in the self-magnetic field (beam pinch) limits the beam area that can be generated from a single cathode. A simple analytic model is used to derive a scaling relationship for beam pinch in both geometries of the form V/sup 1/2/ w/d = $alpha$ where V is the diode voltage, w the beam width, d the anode-cathode spacing, and $alpha$ is a weak function of the geometry. Numerical calculations are presented to show the effects of nonuniform electric fields encountered in typical geometries together with supporting experimental measurements. (auth)

Schlitt, L.G.; Bradley, L.P.

1975-11-01T23:59:59.000Z

138

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?

139

Thermal imaging diagnostics of high-current electron beams  

SciTech Connect

The thermal imaging diagnostics of measuring pulsed electron beam energy density is presented. It provides control of the electron energy spectrum and a measure of the density distribution of the electron beam cross section, the spatial distribution of electrons with energies in the selected range, and the total energy of the electron beam. The diagnostics is based on the thermal imager registration of the imaging electron beam thermal print in a material with low bulk density and low thermal conductivity. Testing of the thermal imaging diagnostics has been conducted on a pulsed electron accelerator TEU-500. The energy of the electrons was 300-500 keV, the density of the electron current was 0.1-0.4 kA/cm{sup 2}, the duration of the pulse (at half-height) was 60 ns, and the energy in the pulse was up to 100 J. To register the thermal print, a thermal imager Fluke-Ti10 was used. Testing showed that the sensitivity of a typical thermal imager provides the registration of a pulsed electron beam heat pattern within one pulse with energy density over 0.1 J/cm{sup 2} (or with current density over 10 A/cm{sup 2}, pulse duration of 60 ns and electron energy of 400 keV) with the spatial resolution of 0.9-1 mm. In contrast to the method of using radiosensitive (dosimetric) materials, thermal imaging diagnostics does not require either expensive consumables, or plenty of processing time.

Pushkarev, A.; Kholodnaya, G.; Sazonov, R.; Ponomarev, D. [Tomsk Polytechnic University, 30 Lenin Ave., Tomsk, 634050 (Russian Federation)

2012-10-15T23:59:59.000Z

140

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

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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141

Erosion tests of materials by energetic particle beams  

DOE Green Energy (OSTI)

The internal components of magnetic fusion devices must withstand erosion from and high heat flux of energetic plasma particles. The selection of materials for the construction of these components is important to minimize contamination of the plasma. In order to study various materials' comparative resistance to erosion by energetic particles and their ability to withstand high heat flux, water-cooled copper swirl tubes coated or armored with various materials were subjected to bombardment by hydrogen and helium particle beams. Materials tested were graphite, titanium carbide (TiC), chromium, nickel, copper, silver, gold, and aluminum. Details of the experimental arrangement and methods of application or attachment of the materials to the copper swirl tubes are presented. Results including survivability and mass losses are discussed.

Schechter, D.E.; Becraft, W.R.; Hoffman, D.J.; Sluss, F.; Tsai, C.C.

1985-07-01T23:59:59.000Z

142

Momentum spread in a relativistic electron beam in an undulator  

Science Conference Proceedings (OSTI)

The motion of the relativistic electron beam in the spatially periodic magnetic field of an undulator has been considered taking into account the effect of the incoherent field of the spontaneous undulator radiation on the motion of the electrons. An expression for the rms momentum of the electrons has been obtained. It has been shown that the momentum spread in the ultrarelativistic electron beam increases in the spontaneous incoherent emission mode. Conditions for the self-amplification of the spontaneous undulator radiation in ultrashort-wavelength free-electron lasers have been discussed.

Ognivenko, V. V., E-mail: ognivenko@kipt.kharkov.ua [National Science Center Kharkov Institute of Physics and Technology (Ukraine)

2012-11-15T23:59:59.000Z

143

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

144

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

145

Transmission of Megawatt Relativistic Electron Beams Through Millimeter Apertures  

E-Print Network (OSTI)

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

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

2013-05-01T23:59:59.000Z

146

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

147

Evaluation of Electron-Beam Cold Hearth Refining (EBCHR) of ...  

Science Conference Proceedings (OSTI)

EVALUATION OF ELECTRON-BEAM COLD HEARTH REFINING (EBCHR) OF. VIRGIN AND REVERT IN738LC. P.N. Quested*, M. McLean* and M.R. Winstonet.

148

Microsoft Word - Emittance Evolution of the Drive Electron Beam...  

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

WF-NOTE-237 Dec. 21, 2007 Emittance Evolution of the Drive Electron Beam in Helical Undulator for ILC Positron Source Wanming Liu, Wei Gai, Michael Borland, Aimin Xiao, and...

149

A New High Intensity Electron Beam for Wakefield Acceleration...  

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

HIGH INTENSITY ELECTRON BEAM FOR WAKEFIELD ACCELERATION STUDIES* M.E. Conde , W. Gai, C. Jing, R. Konecny, W. Liu, J.G. Power, H. Wang, Z. Yusof ANL, Argonne, IL 60439, USA...

150

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

151

G4beamline Particle Tracking in Matter Dominated Beam Lines  

Science Conference Proceedings (OSTI)

The G4beamline program is a useful and steadily improving tool to quickly and easily model beam lines and experimental equipment without user programming. It has both graphical and command-line user interfaces. Unlike most accelerator physics codes, it easily handles a wide range of materials and fields, being particularly well suited for the study of muon and neutrino facilities. As it is based on the Geant4 toolkit, G4beamline includes most of what is known about the interactions of particles with matter. We are continuing the development of G4beamline to facilitate its use by a larger set of beam line and accelerator developers. A major new feature is the calculation of space-charge effects. G4beamline is open source and freely available at http://g4beamline.muonsinc.com

T.J. Roberts, K.B. Beard, S. Ahmed, D. Huang, D.M. Kaplan

2011-03-01T23:59:59.000Z

152

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

DOE Patents (OSTI)

An Intense Relativistic Electron Beam (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.

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

1986-04-25T23:59:59.000Z

153

Controlling the betatron oscillations of a wakefield-accelerated electron beam by temporally asymmetric laser pulses  

Science Conference Proceedings (OSTI)

Based on two-dimensional particle-in-cell simulations, we investigated the electron beam's transverse oscillations by temporally asymmetric laser pulses in laser wakefield acceleration. Of particular interest in this article are the effects of ultrashort laser pulses having sharp rising and slow falling time scales. In this situation, the accelerated electron beam interacts directly with the laser field and undergoes transverse oscillations due to a phase-slip with the laser field. This oscillation can be matched with the betatron oscillation due to the focusing force of the ions, which can lead to a large transverse oscillation amplitude due to the resonance between them. Furthermore, in this case, the electron beam can be microbunched at the laser wavelength, which may provide the possibility for generation of a coherent synchrotron radiation.

Nam, Inhyuk [Graduate Program of Photonics and Applied Physics, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of); Hur, Min Sup [School of Electrical and Computer Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 689-798 (Korea, Republic of); Uhm, Han Sup [Electrophysics Department, Kwangwoon University, Seoul 139-701 (Korea, Republic of); Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of); Hafz, Nasr A. M.; Suk, Hyyong [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712 (Korea, Republic of)

2011-04-15T23:59:59.000Z

154

Pulsed particle beam vacuum-to-air interface  

DOE Patents (OSTI)

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

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

1988-01-01T23:59:59.000Z

155

Particle-in-cell simulations of plasma accelerators and electron-neutral collisions  

Science Conference Proceedings (OSTI)

We present 2-D simulations of both beam-driven and laser-driven plasma wakefield accelerators, using the object-oriented particle-in-cell code XOOPIC, which is time explicit, fully electromagnetic, and capable of running on massively parallel supercomputers. Simulations of laser-driven wakefields with low ({approx}10{sup 16} W/cm{sup 2}) and high ({approx}10{sup 18} W/cm{sup 2}) peak intensity laser pulses are conducted in slab geometry, showing agreement with theory and fluid simulations. Simulations of the E-157 beam wakefield experiment at the Stanford Linear Accelerator Center, in which a 30 GeV electron beam passes through 1 m of preionized lithium plasma, are conducted in cylindrical geometry, obtaining good agreement with previous work. We briefly describe some of the more significant modifications of XOOPIC required by this work, and summarize the issues relevant to modeling relativistic electron-neutral collisions in a particle-in-cell code.

Bruhwiler, David L.; Giacone, Rodolfo E.; Cary, John R.; Verboncoeur, John P.; Mardahl, Peter; Esarey, Eric; Leemans, W.P.; Shadwick, B.A.

2001-10-01T23:59:59.000Z

156

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

157

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

158

The polarized electron beam for the SLAC Linear Collider  

E-Print Network (OSTI)

The SLAC Linear Collider has been colliding a polarized electron beam with an unpolarized positron beam at the Z^0 resonance for the SLD experiment since 1992. An electron beam polarization of close to 80% has been achieved for the experiment at luminosities up to 8x10^29 cm^-2 s^-1. This is the world's first and only linear collider, and is a successful prototype for the next generation of high energy electron linear colliders. This paper discusses polarized beam operation for the SLC, and includes aspects of the polarized source, spin transport and polarimetry. Presented at the 12th International Symposium on High Energy Spin Physics held at Amsterdam, The Netherlands September 10-14, 1996.

M. Woods

1996-11-09T23:59:59.000Z

159

Energy Spread Reduction of Electron Beams Produced via Laser Wake  

Science Conference Proceedings (OSTI)

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

Pollock, B

2012-03-19T23:59:59.000Z

160

Electron Beam Instability in Left-Handed Media  

E-Print Network (OSTI)

We predict that two electron beams can develop an instability when passing through a slab of left-handed media (LHM). This instability, which is inherent only for LHM, originates from the backward Cherenkov radiation and results in a self-modulation of the beams and radiation of electromagnetic waves. These waves leave the sample via the rear surface of the slab (the beam injection plane) and form two shifted bright circles centered at the beams. A simulated spectrum of radiation has well-separated lines on top of a broad continuous spectrum, which indicates dynamical chaos in the system. The radiation intensity and its spectrum can be controlled either by the beams' current or by the distance between the two beams.

Yury P. Bliokh; Sergey Savel'ev; Franco Nori

2008-04-08T23:59:59.000Z

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

Thermal response of ceramic components during electron beam brazing  

DOE Green Energy (OSTI)

Ceramics are being used increasingly in applications where high temperatures are encountered such as automobile and gas turbine engines. However, the use of ceramics is limited by a lack of methods capable of producing strong, high temperature joints. This is because most ceramic-ceramic joining techniques, such as brazing, require that the entire assembly be exposed to high temperatures in order to assure that the braze material melts. Alternatively, localized heating using high energy electron beams may be used to selectively heat the braze material. In this work, high energy electron beam brazing of a ceramic part is modeled numerically. The part considered consists of a ceramic cylinder and disk between which is sandwiched an annular washer of braze material. An electron beam impinges on the disk, melting the braze metal. The resulting coupled electron and thermal transport equations are solved using Monte Carlo and finite element techniques. Results indicate that increased electron beam current decreases time to melt as well as required cooling time. Vacuum furnace brazing was also simulated and predicted results indicate increased processing times relative to electron beam brazing.

Voth, T.E.; Gianoulakis, S.E.; Halbleib, J.A.

1996-03-01T23:59:59.000Z

162

The SLAC Polarized Electron Source and Beam for E-158  

E-Print Network (OSTI)

SLAC E-158 is making the first measurement of parity violation in Moller scattering. E-158 measures the right-left cross-section asymmetry, A_LR, in the scattering of a 45-GeV polarized electron beam off unpolarized electrons in a liquid hydrogen target. E-158 plans to measure the expected Standard Model asymmetry of ~10^-7 to an accuracy of better than 10^-8. This paper discusses the performance of the SLAC polarized electron source and beam during E-158's first physics run in April/May 2002.

T. B. Humensky

2003-01-16T23:59:59.000Z

163

Design of the AGS Booster Beam Position Monitor electronics  

SciTech Connect

The operational requirements of the AGS Booster Beam Position Monitor system necessitate the use of electronics with wide dynamic range and broad instantaneous bandwidth. Bunch synchronization is provided by a remote timing sequencer coupled to the local ring electronics via digital fiber-optic links. The Sequencer and local ring circuitry work together to provide single turn trajectory or average orbit and intensity information, integrated over 1 to 225 bunches. Test capabilities are built in for the purpose of enhancing BPM system accuracy. This paper describes the design of the Booster Beam Position Monitor electronics, and presents performance details of the front end processing, acquisition and timing circuitry.

Ciardullo, D.J.; Smith, G.A.; Beadle, E.R.

1991-01-01T23:59:59.000Z

164

Design of the AGS Booster Beam Position Monitor electronics  

SciTech Connect

The operational requirements of the AGS Booster Beam Position Monitor system necessitate the use of electronics with wide dynamic range and broad instantaneous bandwidth. Bunch synchronization is provided by a remote timing sequencer coupled to the local ring electronics via digital fiber-optic links. The Sequencer and local ring circuitry work together to provide single turn trajectory or average orbit and intensity information, integrated over 1 to 225 bunches. Test capabilities are built in for the purpose of enhancing BPM system accuracy. This paper describes the design of the Booster Beam Position Monitor electronics, and presents performance details of the front end processing, acquisition and timing circuitry.

Ciardullo, D.J.; Smith, G.A.; Beadle, E.R.

1991-12-31T23:59:59.000Z

165

Development of a Compact Rotating-Wave Electron Beam Accelerator  

Science Conference Proceedings (OSTI)

We present the successful prototype development results of a novel compact rotating-wave electron beam accelerator (RWA). The RWA uses a single cylindrical cavity holding a transverse-magnetic resonant mode in combination with an axial static magnetic field to accelerate electrons to higher energies. With approximately 80 kilowatts of microwave power fed into a C-band cavity, we have been able to successfully accelerate a 3 keV electron beam to {approx}760 keV. The compact RWA accelerator could be the basis for a new class of compact and affordable 1-10 MeV microwave accelerators for military, medical and industrial applications.

Velazco, Jose E.; Ceperley, Peter H. [Microwave Technologies Incorporated, Fairfax, Virginia 22030 (United States); Departments of Physics and Electrical Engineering, George Mason University, Fairfax, Virginia 22030 (United States)

2003-08-26T23:59:59.000Z

166

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-

167

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

168

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.

169

Experimental Generation and Characterization of Uniformly Filled Ellipsoidal Electron Beam Distributions  

E-Print Network (OSTI)

Experimental Generation and Characterization of Uniformly Filled Ellipsoidal Electron Beam Distributions

Musumeci, P; Rosenzweig, J B; Scoby, C M

2008-01-01T23:59:59.000Z

170

ELECTRON BEAM WELDING OF NUCLEAR FUEL CLADDING COMPONENTS  

SciTech Connect

The rapid technological development of the nuclear and space industries has placed a great demand on metal joining processes. One of the most promising processes is electron beam welding. Welding with the electron beam ofiers high integrity in addition to the ability to fabricate unusual configurations. Advanced nuclear fuels require both reliability and unusual designs for satisfactory operation under extreme conditions of temperature and stress. To investigate the problems and techniques involved in fabricating large, advanced nuclear fuel components from Zircaloy-2 material, several cladding pieces were designed and built using the electron beam process. These designs included five basic joint types for assembling the cladding. Destructive and nondestructive examinations were employed including corrosion testing and extensive metallographic examination. Weldment size, fit-up'' of the parts to be joined, fixturing and work carriage mechanisms, as they pertain to electron beam welding, are also discussed. The electron beam process has been demonstrated as a very satisfactory method for fabricating unusual fuel cladding. Fuel cladding components with lengths up to 8 ft have been fabricated for in-reactor irradiation. (auth)

Klein, R.F.

1963-10-01T23:59:59.000Z

171

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

172

Electron Beam Transport in Advanced Plasma Wave Accelerators  

SciTech Connect

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

Williams, Ronald L

2013-01-31T23:59:59.000Z

173

Observations of underdense plasma lens focusing of relativistic electron beams  

Science Conference Proceedings (OSTI)

Focusing of a 15 MeV, 19 nC electron bunch by an underdense plasma lens operated just beyond the threshold of the underdense condition has been demonstrated in experiments at the Fermilab NICADD Photoinjector Laboratory (FNPL). The strong 1.9 cm focal-length plasma-lens focused both transverse directions simultaneously and reduced the minimum area of the beam spot by a factor of 23. Analysis of the beam-envelope evolution observed near the beam waist shows that the spherical aberrations of this underdense lens are lower than those of an overdense plasma lens, as predicted by theory. Correlations between the beam charge and the properties of the beam focus corroborate this conclusion.

Thompson, M.C.; /UCLA /LLNL, Livermore; Badakov, H.; Rosenzweig, J.B.; Travish, G.; /UCLA; Fliller, R.; Kazakevich, G.M.; Piot, P.; Santucci, J.; /Fermilab; Li, J.; Tikhoplav, R.; /Rochester U.

2007-06-01T23:59:59.000Z

174

An interference wiggler for precise diagnostics of electron beam energy  

SciTech Connect

Relativistic electrons passing through two identical magnetic sections generate synchrotron radiation whose spectrum is strongly modulated as the photon energy varies. The modulation is caused by the interference of radiation from each section, and has been observed in the spectrum of spontaneous radiation from transverse optical klystron which utilizes two undulators. In this paper, another device based on two simple wigglers is analyzed. The device, which will be called the interference wiggler, can be used for precise diagnostics of electron beam energy; by analyzing the modulated spectrum with a monochromator, the electron energy can be determined up to an accuracy of 10/sup -3/ or 10/sup -4/. General design criteria for interference wigglers are developed. Several example designs are given for measurement of the electron energy for the planned electron beam facility at CEBAF for the 1 to 2 GeV Light Source at Berkeley.

Kim, Kwang-Je

1987-03-01T23:59:59.000Z

175

Study on the Effect of Energy Parameter of Electron on the Percentage Depth Dose of Electron Beam Using Monte Carlo Method  

Science Conference Proceedings (OSTI)

In medical linear accelerator, the energy parameter of electron plays important role to produce electron beam. The percentage depth dose of electron beams takes account not only on the value of electron's energy, but also on the type of electron's energy. The aims of this work are to carry on the effect of energy parameter of electron on the percentage depth dose of electron beam. Monte Carlo method is chosen in this project, due to the superior of this method for simulating the random process such as the transport particle in matter. The DOSXYZnrc usercode was used to simulate the electron transport in water phantom. Two aspects of electron's energy parameter were investigated using Monte Carlo simulations. In the first aspect, electron energy's value was varied also its spectrum. In the second aspect, the geometry of electron's energy was taken account on. The parallel beam and the point source were chosen as the geometry of The measurements of percentage depth dose were conducted to compare with its simulation. The ionization chamber was used in these measurements. Presentation of the results of this work is given not only based on the shape of the percentage depth dose from the simulation and measurement, but also on the other aspect in its curve. The result of comparison between the simulation and its measurement shows that the shape of its curve depends on the energy value of electron and the type of its energy. The energy value of electron affected the depth maximum of dose.

Haryanto, Freddy [Department of Physics, Institut Teknologi Bandung (Indonesia)

2010-06-22T23:59:59.000Z

176

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

177

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

SciTech Connect

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

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

2012-05-01T23:59:59.000Z

178

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

E-Print Network (OSTI)

2002). J.D. Lawson, “Physics of Charged Particles Beams”, (B. Kusse, J. Moschella, Physics of Fluids 30 , 245 (1987).Davidson and H. Qin, “ Physics of Intense Charged Particle

Kaganovich, I.D.

2010-01-01T23:59:59.000Z

179

The effect of electron beam pitch angle and density gradient on solar type III radio bursts  

SciTech Connect

1.5D particle-in-cell simulations of a hot, low density electron beam injected into magnetized, maxwellian plasma were used to further explore the alternative non-gyrotropic beam driven electromagnetic (EM) emission mechanism, first studied in Tsiklauri, Phys. Plasmas 18, 052903 (2011). Variation of beam injection angle and background density gradient showed that the emission process is caused by the perpendicular component of the beam injection current, whereas the parallel component only produces Langmuir waves, which play no role in the generation of EM waves in our mechanism. Particular emphasis was put on the case, where the beam is injected perpendicularly to the background magnetic field, as this turned off any electrostatic wave generation along the field and left a purely electromagnetic signal in the perpendicular components. The simulations establish the following key findings: (i) Initially, waves at a few {omega}{sub ce}/{gamma} are excited, mode converted and emitted at Almost-Equal-To {omega}{sub pe} (ii) The emission intensity along the beam axis is proportional to the respective component of the kinetic energy of the beam; (iii) The frequency of the escaping EM emission is independent of the injection angle; (iv) A stronger background density gradient causes earlier emission; (v) The beam electron distribution function in phase space shows harmonic oscillation in the perpendicular components at the relativistic gyrofrequency; (vi) The requirement for cyclotron maser emission, ({partial_derivative}f/{partial_derivative}v{sub Up-Tack })>0, is fulfilled; (vii) The degree of linear polarization of the emission is strongly dependent on the beam injection angle; (viii) The generated electromagnetic emission is left-hand elliptically polarized as the pitch angle tends to 90 Degree-Sign ; and (ix) The generated electromagnetic energy is of the order of 0.1% of the initial beam kinetic energy.

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

2012-11-15T23:59:59.000Z

180

High-Power Microwave Switch Employing Electron Beam Triggering  

Science Conference Proceedings (OSTI)

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

Jay L. Hirshfield

2012-09-19T23:59:59.000Z

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.
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181

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

182

Electron beam collector for a microwave power tube  

DOE Patents (OSTI)

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

Dandl, Raphael A. (Oak Ridge, TN)

1980-01-01T23:59:59.000Z

183

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

DOE Patents (OSTI)

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

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

1993-08-10T23:59:59.000Z

184

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

DOE Patents (OSTI)

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

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

1993-01-01T23:59:59.000Z

185

Electron beam irradiation of gemstone for color enhancement  

Science Conference Proceedings (OSTI)

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

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

2012-09-26T23:59:59.000Z

186

Suppression of shot noise and spontaneous radiation in electron beams  

Science Conference Proceedings (OSTI)

Shot noise in the electron beam distribution is the main source of noise in high-gain FEL amplifiers, which may affect applications ranging from single- and multi-stage HGHG FELs to an FEL amplifier for coherent electron cooling. This noise also imposes a fundamental limit of about 10{sup 6} on FEL gain, after which SASE FELs saturate. There are several advantages in strongly suppressing this shot noise in the electron beam, and the corresponding spontaneous radiation. For more than a half-century, a traditional passive method has been used successfully in practical low-energy microwave electronic devices to suppress shot noise. Recently, it was proposed for this purpose in FELs. However, being passive, the method has some significant limitations and is hardly suitable for the highly inhomogeneous beams of modern high-gain FELs. I present a novel active method of suppressing, by many orders-of-magnitude, the shot noise in relativistic electron beams. I give a theoretical description of the process, and detail its fundamental limitation.

Litvinenko,V.

2009-08-23T23:59:59.000Z

187

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

188

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

189

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

SciTech Connect

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

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

2000-08-21T23:59:59.000Z

190

High intensity electron beam ion trap for charge state boosting of radioactive ion beams  

SciTech Connect

A high intensity electron beam ion trap under development at LLNL could be adapted for charge state boosting of radioactive ion beams, enabling a substantial reduction in the size and cost of a post-accelerator. We report estimates of the acceptance, ionization time, charge state distribution, emittance, and beam intensity for charge state boosting of radioactive ions in this device. The estimates imply that, for tin isotopes, over 10{sup 10} ions/s can be ionized to q = 40+ with an absolute emittance of approximately 1 (pi) mm mrad at an energy of 30 x q.k.

Marrs, R.

1998-09-30T23:59:59.000Z

191

Beam Conditioning for Free Electron Lasers:Consequences and Methods  

Science Conference Proceedings (OSTI)

The consequences of beam conditioning in four example cases [VISA, a soft x-ray free-electron laser (FEL), LCLS, and a 'Greenfield' FEL] are examined. It is shown that in emittance limited cases, proper conditioning reduces sensitivity to the transverse emittance and, furthermore, allows for stronger focusing in the undulator. Simulations show higher saturation power, with gain lengths reduced by a factor of 2 or more. The beam dynamics in a general conditioning system are studied, with 'matching conditions' derived for achieving conditioning without growth in the effective emittance. Various conditioning lattices are considered, and expressions derived for the amount of conditioning provided in each case when the matching conditions are satisfied. These results show that there is no fundamental obstacle to producing beam conditioning, and that the problem can be reduced to one of proper lattice design. Nevertheless, beam conditioning will not be easy to implement in practice.

Wolski, A.; Penn, G.; Sessler, A.; Wurtele, J.; /LBL, Berkeley /UC, Berkeley, Astron. Dept.

2010-12-14T23:59:59.000Z

192

COMMISSIONING COSY COOLER WITH ELECTRON BEAM AT NOVOSIBIRSK  

E-Print Network (OSTI)

is assembled in BINP [1]. Results of experiments with high voltage, with electron beam, cascade transformer for distribution power along acceleration tube will be discussed in this report. The COSY cooler is designed HV power supply (plus/minus 30 kV) and power supply of the magnetic coils. The electrical power

Kozak, Victor R.

193

Risk Management Plan Electron Beam Ion Source Project  

E-Print Network (OSTI)

. The estimated costs and contingencies to mitigate these risks are incorporated in the Project baseline costRisk Management Plan for the Electron Beam Ion Source Project (EBIS) Project # 06-SC-002 of Nuclear Physics (SC ­ 26) #12;1. Background and References 1.1 Background The EBIS Project will manage

Homes, Christopher C.

194

Electron beam switched discharge for rapidly pulsed lasers  

DOE Patents (OSTI)

Method and apparatus for electrical excitation of a laser gas by application of a pulsed voltage across the gas, followed by passage of a pulsed, high energy electron beam through the gas to initiate a discharge suitable for laser excitation. This method improves upon current power conditioning techniques and is especially useful for driving rare gas halide lasers at high repetition rates.

Pleasance, Lyn D. (Livermore, CA); Murray, John R. (Danville, CA); Goldhar, Julius (Walnut Creek, CA); Bradley, Laird P. (Livermore, CA)

1981-01-01T23:59:59.000Z

195

Reversible Electron Beam Heating for Suppression of Microbunching Instabilities at Free-Electron Lasers  

SciTech Connect

The presence of microbunching instabilities due to the compression of high-brightness electron beams at existing and future x-ray free-electron lasers (FELs) results in restrictions on the attainable lasing performance and renders beam imaging with optical transition radiation impossible. The instability can be suppressed by introducing additional energy spread, i.e., heating the electron beam, as demonstrated by the successful operation of the laser heater system at the Linac Coherent Light Source. The increased energy spread is typically tolerable for self-amplified spontaneous emission FELs but limits the effectiveness of advanced FEL schemes such as seeding. In this paper, we present a reversible electron beam heating system based on two transverse deflecting radio-frequency structures (TDSs) upstream and downstream of a magnetic bunch compressor chicane. The additional energy spread is introduced in the first TDS, which suppresses the microbunching instability, and then is eliminated in the second TDS. We show the feasibility of the microbunching gain suppression based on calculations and simulations including the effects of coherent synchrotron radiation. Acceptable electron beam and radio-frequency jitter are identified, and inherent options for diagnostics and on-line monitoring of the electron beam's longitudinal phase space are discussed.

Behrens, Christopher; /DESY; Huang, Zhirong; Xiang, Dao; /SLAC

2012-05-30T23:59:59.000Z

196

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

197

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

198

Comparison of the physics of Gas Tungsten Arc Welding (GTAW), Electron Beam Welding (EBW), and Laser Beam Welding (LBW)  

SciTech Connect

The physics governing the applicability and limitations of gas tungsten arc (GTA), electron beam (EB), and laser beam (LB) welding are compared. An appendix on the selection of laser welding systems is included.

Nunes, A.C. Jr.

1985-08-01T23:59:59.000Z

199

Cerenkov light spectrum in an optical fiber exposed to a photon or electron radiation therapy beam  

Science Conference Proceedings (OSTI)

A Cerenkov signal is generated when energetic charged particles enter the core of an optical fiber. The Cerenkov intensity can be large enough to interfere with signals transmitted through the fiber. We determine the spectrum of the Cerenkov background signal generated in a poly(methyl methacrylate) optical fiber exposed to photon and electron therapeutic beams from a linear accelerator. This spectral measurement is relevant to discrimination of the signal from the background, as in scintillation dosimetry using optical fiber readouts. We find that the spectrum is approximated by the theoretical curve after correction for the wavelength dependent attenuation of the fiber. The spectrum does not depend significantly on the angle between the radiation beam and the axis of the fiber optic but is dependent on the depth in water at which the fiber is exposed to the beam.

Lambert, Jamil; Yin Yongbai; McKenzie, David R.; Law, Sue; Suchowerska, Natalka

2009-06-20T23:59:59.000Z

200

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

Science Conference Proceedings (OSTI)

Analytical expressions for the mean energy and range of therapeutic light ion beams and low- and high-energy electrons have been derived

Johanna Kempe; Anders Brahme

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.


201

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

SciTech Connect

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

202

Stabilization of tearing instability and heating of plasma ions by a modulated particle beam  

SciTech Connect

The tearing instability is considered for nonisothermal plasma penetrated by a low-velocity charged-particle beam. Possible stabilization of this instability due to the transformation of the high-frequency wave energy into the energy of a nonlinear ion-acoustic wave is discussed. This phenomenon is equivalent to the nonlinear absorption of the high-frequency waves. The efficiency of heating of heavy particles (ions) by a charged-particle beam is estimated.

Fainshtein, S.M.

1976-09-01T23:59:59.000Z

203

Electron Beam Charge Diagnostics for Laser Plasma Accelerators  

SciTech Connect

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

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

2011-06-27T23:59:59.000Z

204

Effects of e-beam parameters on coherent electron cooling  

Science Conference Proceedings (OSTI)

Coherent Electron Cooling (CeC) requires detailed control of the phase between the hadron an the FEL-amplified wave packet. This phase depends on local electron beam parameters such as the energy spread and the peak current. In this paper, we examine the effects of local density variations on the cooling rates for CeC. Coherent Electron Cooling (CeC) [1] is a new concept in intense, high energy hadron beamcooling, in which the Debye screened charge perturbation calculated in [2] is used to seed a high-gain free electron laser (FEL). Using delays to give the perturbing hadron an energy-dependent longitudinal displacement relative to its frequencymodulated charge perturbation, the hadron receives an energy-dependent kick which reduces its energy variation from the design energy. The equations of motion in [1] assume that the electron bunch is the same physical size as the hadron bunch, and has a homogeneous charge density across the entire bunch. In practice, the electron bunches will be much shorter than the hadron bunch, and this local spacial inhomogeneity in the charge distribution will alter the gain length of the FEL, resulting in both a change in the amplification of the initial signal and a phase shift. In this paper we consider these inhomogeneity effects, determining cooling equations for bunched beam CeC consistent with these effects and determining thresholds for the cooling parameters.

Webb, S.D.; Litvinenko, V.N.; Wang, G.

2011-03-28T23:59:59.000Z

205

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

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. 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.

Giedt, Warren H. (San Jose, CA); Campiotti, Richard (Livermore, CA)

1996-01-01T23:59:59.000Z

206

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

207

Ion Beam Collimation For Improved Resolution In Associated Particle Imaging  

Science Conference Proceedings (OSTI)

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

208

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

209

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

DOE Patents (OSTI)

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

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

1992-10-06T23:59:59.000Z

210

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

DOE Patents (OSTI)

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

Gammel, G.M.; Kugel, H.W.

1991-12-31T23:59:59.000Z

211

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

SciTech Connect

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

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

2005-02-28T23:59:59.000Z

212

New Spectral Method for Halo Particle Definition in Intense Mis-matched Beams  

SciTech Connect

An advanced spectral analysis of a mis-matched charged particle beam propagating through a periodic focusing transport lattice is utilized in particle-in-cell (PIC) simulations. It is found that the betatron frequency distribution function of a mismatched space-charge-dominated beam has a bump-on-tail structure attributed to the beam halo particles. Based on this observation, a new spectral method for halo particle definition is proposed that provides the opportunity to carry out a quantitative analysis of halo particle production by a beam mismatch. In addition, it is shown that the spectral analysis of the mismatch relaxation process provides important insights into the emittance growth attributed to the halo formation and the core relaxation processes. Finally, the spectral method is applied to the problem of space-charge transport limits.

Mikhail A. Dorf, Ronald C. Davidson, and Edward A. Startsev

2011-04-27T23:59:59.000Z

213

Multiple scattering measurements in nuclear emulsions exposed to momentum-analysed particle beams from the CERN proton synchrotron  

E-Print Network (OSTI)

Multiple scattering measurements in nuclear emulsions exposed to momentum-analysed particle beams from the CERN proton synchrotron

Hossain, A; Wataghin, A; CERN. Geneva. Emulsion Experiments Committee

1961-01-01T23:59:59.000Z

214

Construction of Industrial Electron Beam Plant for Wastewater Treatment  

Science Conference Proceedings (OSTI)

A pilot plant for treating 1,000 m3/day of dyeing wastewater with e-beam has been constructed and operated since 1998 in Daegu, Korea together with the biological treatment facility. The wastewater from various stages of the existing purification process has been treated with electron beam in this plant, and it gave rise to elaborate the optimal technology of the electron beam treatment of wastewater with increased reliability at instant changes in the composition of wastewater. Installation of the e-beam pilot plant resulted in decolorizing and destructive oxidation of organic impurities in wastewater, appreciable to reduction of chemical reagent consumption, in reduction of the treatment time, and in increase in flow rate limit of existing facilities by 30-40%. Industrial plant for treating 10,000 m3/day, based upon the pilot experimental result, is under construction and will be finished by 2005. This project is supported by the International Atomic Energy Agency (IAEA) and Korean Government.

Han, B.; Kim, J.; Kim, Y.; Kim, S.; Lee, M.; Choi, J.; Ahn, S.; Makarov, I.E.; Ponomarev, A.V.

2004-10-06T23:59:59.000Z

215

Electron beam-switched discharge for rapidly pulsed lasers  

DOE Patents (OSTI)

A method and apparatus are designed for electrical excitation of a laser gas by application of a pulsed voltage across the gas, followed by passage of a pulsed, high energy electron beam through the gas to initiate a discharge suitable for laser excitation. This method improves upon current power conditioning techniques and is especially useful for driving rare gas halide lasers at high repetition rates.

Pleasance, L.D.; Murray, J.R.; Goldhar, J.; Bradley, L.P.

1979-12-11T23:59:59.000Z

216

3D Elemental Mapping of Cells using Electron and Ion Beams  

Science Conference Proceedings (OSTI)

3D Elemental Mapping of Cells Using Electron and Ion Beams. Summary: Although it is the most commonly used technique ...

2012-10-02T23:59:59.000Z

217

High-speed Imaging of the Electron-beam Based Additive ...  

Science Conference Proceedings (OSTI)

Abstract Scope, Oak Ridge National Laboratory (ORNL) has been utilizing the Arcam electron beam melting (EBM) technology to additively manufacture ...

218

New and improved apparatus and method for monitoring the intensities of charged-particle beams  

DOE Patents (OSTI)

Charged particle beam monitoring means are disposed in the path of a charged particle beam in an experimental device. The monitoring means comprise a beam monitoring component which is operable to prevent passage of a portion of beam, while concomitantly permitting passage of another portion thereof for incidence in an experimental chamber, and providing a signal (I/sub m/) indicative of the intensity of the beam portion which is not passed. Caibration means are disposed in the experimental chamber in the path of the said another beam portion and are operable to provide a signal (I/sub f/) indicative of the intensity thereof. Means are provided to determine the ratio (R) between said signals whereby, after suitable calibration, the calibration means may be removed from the experimental chamber and the intensity of the said another beam portion determined by monitoring of the monitoring means signal, per se.

Varma, M.N.; Baum, J.W.

1981-01-16T23:59:59.000Z

219

Laser-driven relativistic electron beam interaction with solid dielectric  

SciTech Connect

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

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

2012-07-30T23:59:59.000Z

220

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

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

The electron beam cure of epoxy paste adhesives  

Science Conference Proceedings (OSTI)

Recently developed epoxy paste adhesives were electron beam cured and experimentally explored to determine their suitability for use in an aerospace-quality aircraft component. There were two major goals for this program. The first was to determine whether the electron beam-curable past adhesives were capable of meeting the requirements of the US Air Force T-38 supersonic jet trainer composite windshield frame. The T-38 windshield frame`s arch is currently manufactured by bonding thin stainless steel plies using an aerospace-grade thermally-cured epoxy film adhesive. The second goal was to develop the lowest cost hand layup and debulk process that could be used to produce laminated steel plies with acceptable properties. The laminate properties examined to determine adhesive suitability include laminate mechanical and physical properties at room, adhesive tack, out-time capability, and the debulk requirements needed to achieve these properties. Eighteen past adhesives and four scrim cloths were experimentally examined using this criteria. One paste adhesive was found to have suitable characteristics in each of these categories and was later chosen for the manufacture of the T-38 windshield frame. This experimental study shows that by using low-cost debulk and layup processes, the electron beam-cured past adhesive mechanical and physical properties meet the specifications of the T-38 composite windshield frame.

Farmer, J.D. [Air Force Advanced Composites Program office, McClellan AFB, CA (United States); Janke, C.J. [Oak Ridge National Lab., TN (United States). Oak Ridge Centers for Manufacturing Technology; Lopata, V.J. [Atomic Energy of Canada Ltd., Pinawa, Manitoba (Canada). Whiteshell Labs.

1998-07-01T23:59:59.000Z

222

2D Optical Streaking for Ultra-Short Electron Beam Diagnostics  

SciTech Connect

We propose a novel approach to measure short electron bunch profiles at micrometer level. Low energy electrons generated during beam-gas ionization are simultaneously modulated by the transverse electric field of a circularly-polarized laser, and then they are collected at a downstream screen where the angular modulation is converted to a circular shape. The longitudinal bunch profile is simply represented by the angular distribution of the electrons on the screen. We only need to know the laser wavelength for calibration and there is no phase synchronization problem. Meanwhile the required laser power is also relatively low in this setup. Some simulations examples and experimental consideration of this method are discussed. At Linac Coherent Light Source (LCLS), an S-band RF transverse deflector (TCAV) is used to measure the bunch length with a resolution 10 femtosecond (fs) rms. An X-band deflector (wavelength 2.6cm) is proposed recently to improve the resolution. However, at the low charge operation mode (20pC), the pulse length can be as short as fs. It is very challenging to measure femtosecond and sub-femtosecond level bunch length. One of the methods is switching from RF to {mu}m level wavelength laser to deflect the bunch. A powerful laser ({approx}10s GW) is required to deflect such a high energy beam (GeV) in a wiggler. Synchronization is another difficulty: the jitter between the bunch and the laser can be larger than the laser wavelength, which makes single-shot measurement impossible. To reduce the laser power, we propose to use ionized electrons from high energy electron beam and gas interaction for high energy electron bunch diagnostics. Similarly, the femtosecond X-ray streak camera uses X-ray ionization electrons to measure the X-ray pulse. The electrons generated by beam-gas ionization have low energy (eVs). Therefore, a lower laser power is possible to deflect such low energy electrons. Note that there is no field ionization in our case. To avoid field ionization, which occurs in plasma case, gases species with high field ionization threshold should be considered. For a linear polarized laser, the kick to the ionized electrons depends on the phase of the laser when the electrons are born and the unknown timing jitter between the electron beam and laser beam makes the data analysis very difficult. Here we propose to use a circular polarized laser to do a 2-dimensional (2D) streaking (both x and y) and measure the bunch length from the angular distribution on the screen, where the phase jitter causes only a rotation of the image on the screen without changing of the relative angular distribution. Also we only need to know the laser wavelength for calibration. A similar circular RF deflecting mode was used to measure long bunches. We developed a numerical particle-in-Cell (PIC) code to study the dynamics of ionization electrons with the high energy beam and the laser beam.

Ding, Y.T.; Huang, Z.; Wang, L.; /SLAC

2011-12-14T23:59:59.000Z

223

Self-modulation of long electron beams in plasma at PITZ  

Science Conference Proceedings (OSTI)

The Photo Injector Test facility at DESY, Zeuthen site (PITZ), offers the unique possibility to study and demonstrate the self-modulation of long electron bunches in plasma. A set of numerical simulations with the particle-in-cell code OSIRIS has been carried out for a better understanding of the process. Of particular interest is the measurement of the energy modulation induced to the beam itself by means of the generated wakefields in plasma. It will reflect the key properties of the accelerating electric fields such as their magnitude and their phase velocity, both of significant importance in the design of experiments relying on this technique.

Martinez de la Ossa, A.; Gross, M.; Gruener, F.; Khojoyan, M.; Krasilnikov, M.; Oppelt, A.; Stephan, F.; Schroeder, C. B.; Osterhoff, J. [Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg (Germany); Institut fuer Experimentalphysik, Universitaet Hamburg, 22761 Hamburg (Germany); Deutsches Elektronen-Synchrotron (DESY), 22607 Hamburg (Germany); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Institut fuer Experimentalphysik, Universitaet Hamburg, 22761 Hamburg (Germany)

2012-12-21T23:59:59.000Z

224

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

SciTech Connect

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

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

2005-09-01T23:59:59.000Z

225

Issues for Bringing Electron Beam Irradiators On-Line  

Science Conference Proceedings (OSTI)

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

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

1999-04-20T23:59:59.000Z

226

Initial commissioning results with the NSCL Electron Beam Ion Trap  

Science Conference Proceedings (OSTI)

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

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

2012-02-15T23:59:59.000Z

227

Status of Jefferson Lab's Load Locked Polarized Electron Beam  

DOE Green Energy (OSTI)

A new 100 kV load locked polarized electron gun has been built at Jefferson Lab. The gun is installed in a test stand on a beam line that resembles the first few meters of the CEBAF nuclear physics photoinjector. With this gun, a GaAs photocathode can be loaded from atmosphere, hydrogen cleaned, activated and taken to high voltage in less than 8 hours. The gun is a three chamber design, with all of the moving parts remaining at ground potential during gun operation. Studies of gun performance, photocathode life times, transverse emittance at high bunch charge, helicity correlated effects and beam polarizations from new photocathode samples will all be greatly facilitated by the use of this load locked gun.

M.L. Stutzman; P. Adderley; M. Baylac; J. Clark; A. Day; J. Grames; J. Hansknecht; M. Poelker

2002-09-01T23:59:59.000Z

228

High quality single shot diffraction patterns using ultrashort megaelectron volt electron beams from a radio frequency photoinjector  

SciTech Connect

Single shot diffraction patterns using a 250-fs-long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the rf photoinjector off a 100-nm-thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction.

Musumeci, P.; Moody, J. T.; Scoby, C. M.; Gutierrez, M. S. [Department of Physics and Astronomy, UCLA, Los Angeles, California 90095 (United States); Bender, H. A.; Wilcox, N. S. [National Security Technologies, LLC, Los Alamos Operations, Los Alamos, New Mexico 87544 (United States)

2010-01-15T23:59:59.000Z

229

High Quality Single Shot Diffraction Patterns Using Ultrashort Megaelectron Volt Electron Beams from a Radio Frequency Photoinjector  

SciTech Connect

Single shot diffraction patterns using a 250 fs long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the RF photoinjector off a 100 nm thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction

P. Musumeci, J. T. Moody, C. M. Scoby, M. S. Gutierrez, H. A. Bender, N. S. Wilcox

2010-01-01T23:59:59.000Z

230

Development of a chemical dosimeter for electron beam food irradiation  

E-Print Network (OSTI)

A chemical solution composed of paraffin wax, chloroform, and methyl yellow biological indicator was shaped into a solid 3-D apple phantom to determine absorbed dose from e-beams and X-rays. The purpose of this research was to determine the most uniform irradiation treatment on apple-phantoms (a complex shaped target) and GAFCHROMICÂź 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. Irradiation with the VDG accelerator confirmed that tilting the apple-phantom yaxis towards the e-beam source by 90 degrees, 45, and 22.5 degrees resulted in more uniform treatment in both the methyl yellow apple phantom and HD-810 film. The phantoms were over-exposed at the top and bottom regions when their y-axis was oriented exactly parallel to the e-beam at 22.5-degrees. The 45-degree orientation ensured uniformity throughout the whole apple surface without overexposing it at the top and bottom. In contrast, the 90-degree orientation resulted in the least effective treatment with the bottom and top region not receiving any radiation. A 10 MeV dual e-beam showed uniform penetration from top to bottom in the HD-810 film and apple phantoms. The HD-810 film responded linearly with doses up to 1.5 kGy while the methyl yellow response was non-linear up to 0.5 kGy maximum. The X-ray irradiation completely penetrated the apple phantoms from top to bottom showing excellent lateral uniformity at different penetration depths.

Rivadeneira, Ramiro Geovanny

2003-05-01T23:59:59.000Z

231

SEARCH FOR CHARGED PARTICLES WITH REST MASS BETWEEN THAT OF THE ELECTRON AND MU-MESON  

SciTech Connect

An attempt was made to produce charged particles with rest mass between that of the electron and mu meson (hereafter called submuons) by electromagnetic pair pronduction from C nuclei. The incident photon beam was obtained by bombarding a thick C block with an 800-Mev electron beam. The same block served as the target for the production process. Only one member of the produced pair was to be observed. The momentum of the secondary particles (300 Mev/c) was determined by a zero-dispersion, doublefocusing magnetic spectrometer. The particles traversing the spectrometer were detected by a 6-courter telescope, in which the counters were separated by various thicknesses of lead. The signals from the counters were put in coincidence in a 6-channel fast-resolution coincidence circuit. The telescope was sensitive to submuons with rest masses between 175 and 10 electron masses. The expected counting rates were calculated using the Bethe-Heitler and Pauli-Weisskopf formulas for spin 1/2 and spin 0 submuons, respectively. An integration over the variables of the unobserved member of the pair, and thus over the momentum transfer to the C nucleus was performed. The nucleus was treated by a sum rale calculation to take into account both the finite nuclear size and the elastic and inelastic contributions to the cross section. The resulting cross sections were multiplied by the total photon spectrum and the results integrated over the available photon energy. The total photon spectrum included both the real photon spectrum from electron bremsstrshlung in the C target and the virtual photon spectrum associated with the electrons themselves. The expected courting rates varied from 70 to 12,500 counts per l0t7 incident electrons for spin 1/2 submuons with rest masses between 175 and 25 electron masses and half lives in the microsecond region or longer. The similar rates for spin 0 submuons were 10 to 2870 counts. Since only 4.10 plus or minus 2.05 counts per 10/sup 17/ incident electrons were observed, it seems highly unlikely thai particles with rest mass between that of the electron and mu-meson exist. (M.P.G.)

Coward, D.H.

1963-01-01T23:59:59.000Z

232

Supporting soil remediation at Fernald by electron beam methods  

SciTech Connect

Electron beam techniques have been used to characterize uranium-contaminated soils at the Fernald Site, Ohio. The major uranium phases have been identified by analytical electron microscopy (AEM) as uranyl phosphate (autunite), uranium oxide (uraninite), and uranium phosphite [U(PO{sub 3}){sub 4}]. Luminescence and X-ray absorption spectroscopy incorrectly identified uranium oxide hydrate (schoepite) as the major phase in Fernald soils. The solubilities of schoepite and autunite are very different, so a solubility-dependent remediation method selected for schoepite will not be effective for removing autunite. AEM is the only technique capable of precisely identifying unknown submicron phases. The uranium phosphite has been found predominantly at the incinerator site at Fernald. This phase has not been removed successfully by any of the chemical remediation technologies. We suggest that an alternative physical extraction procedure be applied to remove this phase.

Buck, E.C.; Brown, N.R.; Dietz, N.L.; Cunnane, J.C.

1994-02-01T23:59:59.000Z

233

Images of Complex Interactions of an Intense Ion Beam with Plasma Electrons  

SciTech Connect

Ion beam propagation in a background plasma is an important scientific issue for many practical applications. The process of ion beam charge and current neutralization is complex because plasma electrons move in strong electric and magnetic fields of the beam. Computer simulation images of plasma interaction with an intense ion beam pulse are presented.

Igor D. Kaganovich; Edward Startsev; Ronald C. Davidson

2004-08-03T23:59:59.000Z

234

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

235

Nondestructive evaluation of electron-beam braze joins  

Science Conference Proceedings (OSTI)

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

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

1981-08-18T23:59:59.000Z

236

Focused ion beam direct fabrication of micro-optical elements: features compared with laser beam and electron beam direct writing  

E-Print Network (OSTI)

Three types of focused ion beam machine: focused ion beam milling (FIB milling), focused ion beam lithography (FIB lithography), and focused ion beam direct deposition (FIB deposition), are described in detail to compare ...

Fu, Yongqi

237

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

Science Conference Proceedings (OSTI)

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

238

Configurational testing of electron beam ionization for coal fly ash precipitators. Final report, December 2, 1980-August 4, 1983  

Science Conference Proceedings (OSTI)

Progress towards the development of an electron beam precharger for the removal of fly ash from coal-fired boiler flue gas in a two stage precipitator system is both highly visible and promising. A unique Electron Beam Precipitator (EBP) test system has been constructed and put into operation at Florida State University. This system provides a flexible test bed for the assessment of prechanger configurations which utilize the copious ionization produced by energetic electrons. Modules of the test system which incorporates research capabilities in both electron beam treatment and particulate matter control technology have been tested separately and in conjunction. A first generation (Mark I) precharger has been tested and the results show that electron beam energy and precharger geometry must be rigorously matched. Experiments off-line from the test system are underway to determine the optimum geometry for a Mark II precharger. As part of the EBP subsystem development work, a new particle charge-to-radius ratio measurement system has been designed, constructed and put into successful operation. This q/a monitor provides real time measurements and permanent data recording, and it meets the need for particle charge-to-radius measurement in general. Work on particulate control technology at Florida State University has been undertaken with the knowledge that electron beam treatment projects for the removal of SO/sub 2/ and NO/sub x/ from flue gas are being carried out by two companies in the US with DOE support. Once an assessment of the development of this unique control technology method is completed in work subsequent to this contract, the next anticipated step is the development of an intergrated system for the combined removal of SO/sub 2/, NO/sub x/ and coal fly ash. 69 refs., 62 figs., 7 tabs.

Davis, R.H.

1983-01-01T23:59:59.000Z

239

Electronic and Geometric Structures of Small Gold Metal Particles: Particles Size Effects and the Relationship to Catalytic Activity  

SciTech Connect

The structure of supported gold nano-particles is affected by the size of the particles. Smaller metal particles have decreased gold - gold bond lengths, a higher d electron count, and have a more reactive d band. The influence of support is negligible compared to that of particle size.

Bokhoven, Jeroen A. van [Institute for chemical and Bioengineering, ETH Zurich (Switzerland); Miller, Jeffrey T. [BP Research Center, Naperville, IL 60565-8406 (United States)

2007-02-02T23:59:59.000Z

240

Parametric lower-hybrid instability driven by modulated electron beam injection  

SciTech Connect

A modulated electron beam is injected into a low ..beta.. plasma parallel to the confining field to investigate the energy-transfer-rate from the electron beam to the plasma. Parametric excitation of electrostatic lower-hybrid waves and ion cyclotron quasimodes is experimentally identified. The temperature of both ions and electrons is observed to increase significantly concomitant with the growth of the instability.

Allen, G.R.; Owens, D.K.; Seiler, S.W.; Yamada, M.; Ikezi, H.; Porkolab, M.

1978-08-01T23:59:59.000Z

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.


241

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.

Neil, George R. (Williamsburg, VA)

1996-01-01T23:59:59.000Z

242

Sub-5keV electron-beam lithography in hydrogen silsesquioxane resist  

Science Conference Proceedings (OSTI)

We fabricated 9-30nm half-pitch nested Ls and 13-15nm half-pitch dot arrays, using 2keV electron-beam lithography with hydrogen silsesquioxane (HSQ) as the resist. All structures with 15nm half-pitch and above were fully resolved. We observed that the ... Keywords: High resolution, Hydrogen silsesquioxane, Low-energy electron-beam lithography, Low-voltage electron-beam lithography, Proximity effect

Vitor R. Manfrinato; Lin Lee Cheong; Huigao Duan; Donald Winston; Henry I. Smith; Karl K. Berggren

2011-10-01T23:59:59.000Z

243

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

244

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

245

High Power Microwave Switch Employing Electron Beam Triggering  

Science Conference Proceedings (OSTI)

A new type of switch for modulation of the Q-factor of a multi-mode storage resonator in a high-power active microwave pulse compressor is described. The operating principle of the switch is based on a sharp increase in the TE{sub 02{yields}}TE{sub 01} coupling coefficient, when an electron beam is injected into the switch cavity. The switch was tested at low power level in a compressor operated at X-band. A power gain of 19-20 in the compressed pulse with pulse duration of 40-50 ns was achieved. The proposed switch shows good prospects for use in high-power active pulse compressors.

Ivanov, O. A.; Vikharev, A. L. [Institute of Applied Physics RAS, Nizhny Novgorod, 603600 (Russian Federation); Omega-P, Inc., New Haven, Connecticut 06510 (United States); Isaev, V. A.; Lobaev, M. A. [Institute of Applied Physics RAS, Nizhny Novgorod, 603600 (Russian Federation); Hirshfield, J. L. [Omega-P, Inc., New Haven, Connecticut 06510 (United States); Department of Physics, Yale University, New Haven, Connecticut 06511 (United States)

2010-11-04T23:59:59.000Z

246

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

247

Classical and quantum description of electron trapping during the Cherenkov beam instability in plasma  

SciTech Connect

A nonlinear quantum theory of the Cherenkov instability of a nonrelativistic monoenergetic electron beam in a cold plasma is constructed. It is shown that the instability of a low-density beam is almost purely quantum in nature and results from the emission of one quantum of a plasma wave-a plasmon-by the beam electrons. The number of emitted (and absorbed) plasmons increases with beam density, so, in the limit of high-density beams, the instability becomes a classical Cherenkov beam instability in plasma. Some analytic solutions and estimates are found, detailed numerical results are obtained, and the evolution of the quantum distribution function of the beam electrons in different regimes of the beam instability is investigated.

Bobylev, Yu. V.; Kuzelev, M. V. [Moscow State University (Russian Federation)

2010-11-15T23:59:59.000Z

248

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

SciTech Connect

Plasma accelerators may be driven by the ponderomotive force 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 are discussed. Driver propagation is examined, as well as the effects of the excited plasma wave phase velocity. The driver coupling to subsequent plasma accelerator stages for high-energy physics applications is addressed.

Schroeder, C. B.; Esarey, E.; Benedetti, C.; Toth, Cs.; Geddes, C. G. R.; Leemans, W.P.

2010-06-01T23:59:59.000Z

249

Particle beam self-modulation instability in tapered and inhomogeneous plasma  

SciTech Connect

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

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

2011-12-28T23:59:59.000Z

250

An alpha particle measurement system using an energetic neutral helium beam in ITER (invited)  

Science Conference Proceedings (OSTI)

An energetic helium neutral beam is involved in the beam neutralization measurement system of alpha particles confined in a DT fusion plasma. A full size strong-focusing He{sup +} ion source (2 A, the beam radius of 11.3 mm, the beam energy less than 20 keV). Present strong-focusing He{sup +} ion source shows an emittance diagram separated for each beamlet of multiple apertures without phase space mixing, despite the space charge of a beamlet is asymmetric and the beam flow is non-laminar. The emittance of beamlets in the peripheral region was larger than that of center. The heat load to the plasma electrode was studied to estimate the duty factor for the ITER application.

Sasao, M.; Tanaka, N.; Terai, K.; Kaneko, O. [Graduate school of Engineering, Tohoku University, Sendai 980-8579 (Japan); Kisaki, M.; Kobuchi, T.; Tsumori, K.; Okamoto, A.; Kitajima, S. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Shinto, K. [IFMIF R and D Center, Japan Atomic Energy Agency, Rokkasho, Aomori 039-3212 (Japan); Wada, M. [Graduate School of Engineering, Doshisha University, Kyotanabe, Kyoto 610-0321 (Japan)

2012-02-15T23:59:59.000Z

251

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 $N_{\\rm ions} = 10^{18}$ 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 $N_{\\rm ions} = 6\\cdot 10^{17}$ per year.

Orme, Christopher

2009-01-01T23:59:59.000Z

252

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

2009-12-14T23:59:59.000Z

253

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

254

Simulation of heavy charged particle tracks using focused laser beams  

SciTech Connect

A laboratory system utilizing a Q-switched Nd-doped YAG laser is used to simulate the ionization track produced as energetic heavy ions traverse a semiconductor device (resulting in single-event upset effects). Details of the optical design for producing the precisely focused spot and the requirements for fast pulses are described. The advantages and disadvantages of the use of this laboratory simulation are discussed. Laser tests on PIN diodes, p-n junctions, bipolar memories, and power MOSFETs are described and compared to high energy particle tests results.

Richter, A.K.; Arimura, I.

1987-12-01T23:59:59.000Z

255

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

E-Print Network (OSTI)

Beam Test of a Large Area n­on­n Silicon Strip Detector with Fast Binary Readout Electronics Y modules was irradiated with protons to a fluence of 1.2 � 10 14 p/cm 2 . A beam test was carried out in the edge regions were analyzed using the beam test data. High efficiency both for the non

256

Ion and electron beam nanofabrication of the which-way double-slit experiment in a transmission electron microscope  

Science Conference Proceedings (OSTI)

We have realized a which-way experiment closely resembling the original Feynman's proposal exploiting focused ion beam milling to prepare two nanoslits and electron beam induced deposition to grow, selectively over one of them, electron transparent layers of low atomic number amorphous material to realize a which-way detector for high energy electrons. By carrying out the experiment in an electron microscope equipped with an energy filter, we show that the inelastic scattering of electron transmitted through amorphous layers of different thicknesses provides the control of the dissipative interaction process responsible for the localization phenomena which cancels out the interference effects.

Frabboni, Stefano [Department of Physics, University of Modena and Reggio Emilia and CNR-Institute of Nanoscience-S3, via G. Campi 213/a, 41100 Modena (Italy); Gazzadi, Gian Carlo [CNR-Institute of Nanoscience-S3, via G. Campi 213/a, 41100 Modena (Italy); Pozzi, Giulio [Department of Physics, University of Bologna, viale B. Pichat 6/2, 40127 Bologna (Italy)

2010-12-27T23:59:59.000Z

257

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

Science Conference Proceedings (OSTI)

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

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

2005-01-15T23:59:59.000Z

258

Time efficient fabrication of ultra large scale nano dot arrays using electron beam lithography  

Science Conference Proceedings (OSTI)

An astonishingly simple yet versatile alternative method for the creation of ultra large scale nano dot arrays [1-3] utilising the fact that exposure in electron beam lithography (EBL) is performed by addressing single pixels with defined distances is ... Keywords: Electron beam lithography, Nano dot, Patterning, Photonic crystal, Plasmonics

Jochen Grebing; JüRgen FaíBender; Artur Erbe

2012-09-01T23:59:59.000Z

259

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

260

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

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

Advanced development of particle beam probe diagnostic systems  

SciTech Connect

This progress report covers the period starting with the approval to go ahead with the 2 MeV heavy ion beam probe (HIBP) for TEXT Upgrade to the submission of the grant renewal proposal. During this period the co-principal investigators, R. L. Hickok and T. P. Crowley have each devoted 45% of their time to this Grant. Their effort has been almost exclusively devoted to the design and fabrication of the 2 MeV HIBP system. The 1989 report that described the advantages of a 2 MeV HIBP for TEXT Upgrade compared to the existing 0.5 MeV HIBP and outlined the design of the 2 MeV system is attached as Appendix A. Since the major effort under the renewal proposal will be the continued fabrication, installation and operation of the 2 MeV system on TEXT Upgrade, we describe some of the unique results that have been obtained with the 0.5 MeV system on TEXT. For completeness, we also include the preliminary operation of the 160 keV HIBP on ATF. We present the present fabrication status of the 2 MeV system with the exception of the electrostatic energy analyzer. The energy analyzer which is designed to operate with 400 kV on the top plate is a major development effort and is treated separately. Included in this section are the results obtained with a prototype no guard ring analyzer, the conceptual design for the 2 MeV analyzer, the status of the high voltage testing of full size analyzer systems and backup plans if it turns out that it is impossible to hold 400 kV on an analyzer this size.

Hickok, R.L.; Crowley, T.P.; Connor, K.A.

1990-11-01T23:59:59.000Z

262

Absolute energy calibration for relativistic electron beams with pointing instability from a laser-plasma accelerator  

Science Conference Proceedings (OSTI)

The pointing instability of energetic electron beams generated from a laser-driven accelerator can cause a serious error in measuring the electron spectrum with a magnetic spectrometer. In order to determine a correct electron spectrum, the pointing angle of an electron beam incident on the spectrometer should be exactly defined. Here, we present a method for absolutely calibrating the electron spectrum by monitoring the pointing angle using a scintillating screen installed in front of a permanent dipole magnet. The ambiguous electron energy due to the pointing instability is corrected by the numerical and analytical calculations based on the relativistic equation of electron motion. It is also possible to estimate the energy spread of the electron beam and determine the energy resolution of the spectrometer using the beam divergence angle that is simultaneously measured on the screen. The calibration method with direct measurement of the spatial profile of an incident electron beam has a simple experimental layout and presents the full range of spatial and spectral information of the electron beams with energies of multi-hundred MeV level, despite the limited energy resolution of the simple electron spectrometer.

Cha, H. J.; Choi, I. W.; Kim, H. T.; Kim, I J.; Nam, K. H.; Jeong, T. M.; Lee, J. [Advanced Photonics Research Institute, Gwangju Institute of Science and Technology, Gwangju 500-712 (Korea, Republic of)

2012-06-15T23:59:59.000Z

263

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

264

Bending of metal-filled carbon nanotube under electron beam irradiation  

Science Conference Proceedings (OSTI)

Electron beam irradiation induced, bending of Iron filled, multiwalled carbon nanotubes is reported. Bending of both the carbon nanotube and the Iron contained within the core was achieved using two approaches with the aid of a high resolution electron microscope (HRTEM). In the first approach, bending of the nanotube structure results in response to the irradiation of a pristine kink defect site, while in the second approach, disordered sites induce bending by focusing the electron beam on the graphite walls. The HRTEM based in situ observations demonstrate the potential for using electron beam irradiation to investigate and manipulate the physical properties of confined nanoscale structures.

Misra, Abha [Department of Instrumentation and Applied Physics, Indian Institute of Science, Bangalore, Karnataka, 560012 (India)

2012-03-15T23:59:59.000Z

265

Design of a proton-electron beam overlap monitor for the new RHIC electron lens, based on detecting energetic backscattered electrons  

SciTech Connect

The optimal performance of the two electron lenses that are being implemented for high intensity polarized proton operation of RHIC requires excellent collinearity of the {approx}0.3 mm RMS wide electron beams with the proton bunch trajectories over the {approx}2m interaction lengths. The main beam overlap diagnostic tool will make use of electrons backscattered in close encounters with the relativistic protons. These electrons will spiral along the electron guiding magnetic field and will be detected in a plastic scintillator located close to the electron gun. A fraction of these electrons will have energies high enough to emerge from the vacuum chamber through a thin window thus simplifying the design and operation of the detector. The intensity of the detected electrons provides a measure of the overlap between the e- and the opposing proton beams. Joint electron arrival time and energy discrimination may be used additionally to gain some longitudinal position information with a single detector per lens.

Thieberger T.; Beebe, E.; Fischer, W.; Gassner, D.; Gu, X.; Hamdi, K.; Hock, J.; Minty, M.; Miller, T.; Montag, C.; Pikin, A.

2012-04-15T23:59:59.000Z

266

Rapid plasma heating by collective interactions, using strong turbulence and relativistic electron beams  

SciTech Connect

A multi-kilovolt, moderate density plasma was generated in a magnetic mirror confinement system by two methods: turbulent heating and relativistic electron beam. Extensive diagnostic development permitted the measurement of important plasma characteristics, leading to interesting and novel conclusions regarding heating and loss mechanisms. Electron and ion heating mechanisms were categorized, and parameter studies made to establish ranges of importance. Nonthermal ion and electron energy distributions were measured. Beam propagation and energy deposition studies yielded the spatial dependence of plasma heating.

Wharton, C.B.

1977-01-01T23:59:59.000Z

267

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

Science Conference Proceedings (OSTI)

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

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

2012-01-15T23:59:59.000Z

268

SLAC's Polarized Electron Source Laser System and Minimization of Electron Beam Helicity Correlations for the E-158 Parity Violation Experiment  

E-Print Network (OSTI)

SLAC E-158 is an experiment designed to make the first measurement of parity violation in Moller scattering. E-158 will measure the right-left cross-section asymmetry, A_LR^Moller, in the elastic scattering of a 45-GeV polarized electron beam off unpolarized electrons in a liquid hydrogen target. E-158 plans to measure the expected Standard Model asymmetry of ~10^-7 to an accuracy of better than 10^-8. To make this measurement, the polarized electron source requires for operation an intense circularly polarized laser beam and the ability to quickly switch between right- and left-helicity polarization states with minimal right-left helicity-correlated asymmetries in the resulting beam parameters (intensity, position, angle, spot size, and energy), ^beam A_LR's. This laser beam is produced by a unique SLAC-designed flashlamp-pumped Ti:Sapphire laser and is propagated through a carefully designed set of polarization optics. We analyze the transport of nearly circularly polarized light through the optical system and identify several mechanisms that generate ^beam A_LR's. We show that the dominant effects depend linearly on particular polarization phase shifts in the optical system. We present the laser system design and a discussion of the suppression and control of ^beam A_LR's. We also present results on beam performance from engineering and physics runs for E-158.

T. B. Humensky; R. Alley; A. Brachmann; M. J. Browne; G. D. Cates; J. Clendenin; J. deLamare; J. Frisch; T. Galetto; E. W. Hughes; K. S. Kumar; P. Mastromarino; J. Sodja; P. A. Souder; J. Turner; M. Woods

2002-09-18T23:59:59.000Z

269

Rapid tooling by electron-beam vapor deposition  

Science Conference Proceedings (OSTI)

Electron-beam physical vapor deposition (EBPVD) of tooling metal, onto a shaped substrate to produce a replica of the substrate surface, offers the potential for significant cost savings over present methods of injection mold manufacturing. These savings are realized by the high deposition rate and the corresponding short manufacturing times provided by the EBPVD process. However, on route to realizing these gains, there are process technical issues which need to be resolved. Mold surfaces typically contain relatively high aspect ratio details that must be replicated to dimensional tolerances within +/- 2 mils. The deposited mold material must also provide high surface hardness and high fracture toughness. Good quality grain structure can be obtained in deposited Al 10-wt% Cu mold material when the substrate and corresponding deposit are at high process temperature. However, the resulting mold is subject to distortion during cooldown due to differential temperatures and shrinkage rates. Thermally controlled cooldown and the use of crushable substrate materials reduce these distortions, but not to the required levels of tolerance. Deposition of the Al-Cu at lower temperature produces columnar, poorly joined grains which result in a brittle and weakened mold material. When Al 10-wt% Cu metal vapor is deposited across high aspect ratio step features on the substrate surface, a grain growth defect can form in the step-shadowed regions of the deposited material, alongside the step feature. The step coverage defect consists of entrained voids which persist at intermediate deposition temperatures and produce a weakened mold. This final 1997 LDRD report investigates causes of this step coverage defect and offers methods for their control and elimination.

Meier, T. C., LLNL

1998-02-25T23:59:59.000Z

270

Pierce-Wiggler electron beam system for 250 GHz GYRO-BWO: Final report  

Science Conference Proceedings (OSTI)

This final report summarizes the design and performance of the VUW-8028 Pierce-Wiggler electron beam systems, which can be used to power high frequency gyro-BWO's. The operator's manual for this gyro-BWO beamstick is included as appendix A. Researchers at Lawrence Livermore National Laboratory (LLNL) are developing a gyro-BWO with a center frequency of 250 GHz, 6% bandwidth, and 10 kV peak output power. The gyro-BWO will be used to drive a free electron laser amplifier at LLNL. The electron beam requirements of the gyro-BWO application are: Small beam size, .100 inch at 2500 gauss axial magnetic field; a large fraction of the electron energy in rotational velocity; ability to vary the electrons' axial velocity easily, for electronic tuning; and low velocity spread i.e. little variation in the axial velocities of the electrons in the interaction region. 1 ref., 13 figs.

Pirkle, D.R.; Alford, C.W.; Anderson, M.H.; Garcia, R.F.; Legarra, J.R.; Nordquist, A.L.

1989-01-01T23:59:59.000Z

271

NIST Scientists Use Electron Beam to Unravel the Secrets of ...  

Science Conference Proceedings (OSTI)

... a threshold voltage of about 15-20 millivolts, the probability for switching per electron is constant, meaning that the electrons contain sufficient ...

2013-08-08T23:59:59.000Z

272

Experimental study of electron beam induced removal of H/sub 2/S from geothermal fluids  

DOE Green Energy (OSTI)

The treatment of geothermal steam by electron beam irradiation is a potential alternative method of H/sub 2/S removal which can be applied upstream or downstream and has no chemical requirements. The experimental work reported here examines the effectiveness of electron beam treatment of geothermal fluids. These fluids are produced by combining the constituents in a heated cell, which contains an electron beam transparent window. Irradiation of the contents and subsequent chemical analysis allows an evaluation of effectiveness. These results are used for a commercial feasibility assessment.

Helfritch, D.J.; Singhvi, R.; Evans, R.D.; Reynolds, W.E.

1983-09-01T23:59:59.000Z

273

Design and fabrication of densely integrated silicon quantum dots using a VLSI compatible hydrogen silsesquioxane electron beam lithography process  

Science Conference Proceedings (OSTI)

Hydrogen silsesquioxane (HSQ) is a high resolution negative-tone electron beam resist allowing for direct transfer of nanostructures into silicon-on-insulator. Using this resist for electron beam lithography, we fabricate high density lithographically ... Keywords: Electron beam resist, HSQ, High-resolution, Nanolithography, SET, SOI

Y. P. Lin; M. K. Husain; F. M. Alkhalil; N. Lambert; J. Perez-Barraza; Y. Tsuchiya; A. J. Ferguson; H. M. H. Chong; H. Mizuta

2012-10-01T23:59:59.000Z

274

In-situ monitoring of electron beam induced deposition by atomic force microscopy in a scanning electron microscope  

Science Conference Proceedings (OSTI)

A new type of atomic force microscope is proposed for atomic force microscopic analysis inside a scanning electron microscope. We attached a piezoresisitive atomic force microscopic cantilever to a micro manipulator to achieve a compact and guidable ... Keywords: atomic force, electron beam induced deposition, in-situ monitoring, local gas injection, micro manipulator, microscope

S. Bauerdick; C. Burkhardt; R. Rudorf; W. Barth; V. Bucher; W. Nisch

2003-06-01T23:59:59.000Z

275

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

276

Mode particle resonances during near-tangential neutral beam injection in large tokamaks  

SciTech Connect

Coherent magnetohydrodynamic modes have been observed during neutral beam injection in TFTR and JET. Periodic bursts of oscillations were detected with several plasma diagnostics, and Fokker-Planck calculations show that the populations of trapped particles in both tokamaks are sufficient to account for fishbone destabilization. Estimates of mode parameters are in reasonable agreement with the experiments, and they indicate that the fishbone mode may continue to affect the performance of intensely heated tokamaks. 13 refs., 1 fig., 1 tab.

Kaita, R.; White, R.B.; Morris, A.W.; Fredrickson, E.D.; McGuire, K.M.; Medley, S.S.; Scott, S.D.

1988-01-01T23:59:59.000Z

277

Temporal behavior of neutral particle fluxes in TFTR (Tokamak Fusion Test Reactor) neutral beam injectors  

SciTech Connect

Data from an E {parallel} B charge exchange neutral analyzer (CENA), which views down the axis of a neutral beamline through an aperture in the target chamber calorimeter of the TFTR neutral beam test facility, exhibit two curious effects. First, there is a turn-on transient lasting tens of milliseconds having a magnitude up to three times that of the steady-state level. Second, there is a 720 Hz, up to 20% peak-to-peak fluctuation persisting the entire pulse duration. The turn-on transient occurs as the neutralizer/ion source system reaches a new pressure equilibrium following the effective ion source gas throughput reduction by particle removal as ion beam. Widths of the transient are a function of the gas throughput into the ion source, decreasing as the gas supply rate is reduced. Heating of the neutalizer gas by the beam is assumed responsible, with gas temperature increasing as gas supply rate is decreased. At low gas supply rates, the transient is primarliy due to dynamic changes in the neutralizer line density and/or beam species composition. Light emission from the drift duct corroborate the CENA data. At high gas supply rates, dynamic changes in component divergence and/or spatial profiles of the source plasma are necessary to explain the observations. The 720 Hz fluctuation is attributed to a 3% peak-to-peak ripple of 720 Hz on the arc power supply amplified by the quadratic relationship between beam divergence and beam current. Tight collimation by CENA apertures cause it to accept a very small part of the ion source's velocity space, producing a signal linearly proportional to beam divergence. Estimated fluctuations in the peak power density delivered to the plasma under these conditions are a modest 3--8% peak to peak. The efffects of both phenomena on the injected neutral beam can be ameliorated by careful operion of the ion sources. 21 refs., 11 figs., 2 tabs.

Kamperschroer, J.H.; Gammel, G.M.; Roquemore, A.L.; Grisham, L.R.; Kugel, H.W.; Medley, S.S.; O' Connor, T.E.; Stevenson, T.N.; von Halle, A.; Williams, M.D.

1989-09-01T23:59:59.000Z

278

Design of An 18 MW Beam Dump for 500 GeV Electron/Positron Beams at An ILC  

SciTech Connect

This article presents a report on the progress made in designing 18 MW water based Beam Dumps for electrons or positrons for an International Linear Collider (ILC). Multi-dimensional technology issues have to be addressed for the successful design of the Beam Dump. They include calculations of power deposition by the high energy electron/positron beam bunch trains, computational fluid dynamic analysis of turbulent water flow, mechanical design, process flow analysis, hydrogen/oxygen recombiners, handling of radioactive 7Be and 3H, design of auxiliary equipment, provisions for accident scenarios, remote window exchanger, radiation shielding, etc. The progress made to date is summarized, the current status, and also the issues still to be addressed.

Amann, John; /SLAC; Arnold, Ray; /SLAC; Seryi, Andrei; /SLAC; Walz, Dieter; /SLAC; Kulkarni, Kiran; /Bhabha Atomic Res. Ctr.; Rai, Pravin; /Bhabha Atomic Res. Ctr.; Satyamurthy, Polepalle; /Bhabha Atomic Res. Ctr.; Tiwari, Vikar; /Bhabha Atomic Res. Ctr.; Vincke, Heinz; /CERN

2012-07-05T23:59:59.000Z

279

Design of an 18 MW Beam Dump for 500 GeV Electron/Positron Beams at an ILC  

E-Print Network (OSTI)

This article presents a report on the progress made in designing 18 MW water based Beam Dumps for electrons or positrons for an International Linear Collider (ILC). Multi-dimensional technology issues have to be addressed for the successful design of the Beam Dump. They include calculations of power deposition by the high energy electron/positron beam bunch trains, computational fluid dynamic analysis of turbulent water flow, mechanical design, process flow analysis, hydrogen/oxygen recombiners, handling of radioactive 7Be and 3H, design of auxiliary equipment, provisions for accident scenarios, remote window exchanger, radiation shielding, etc. The progress made to date is summarized, the current status, and also the issues still to be addressed

Amann, John; Seryi, Andrei; Walz, Dieter; Kulkarni, Kiran; Rai, Pravin; Satyamurthy, Polepalle; Tiwari, Vikar; Vincke, Heinz

2010-01-01T23:59:59.000Z

280

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

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

Anomalous electron heating and energy balance in an ion beam generated plasma  

DOE Green Energy (OSTI)

The plasma described in this report is generated by a 15 to 34 kV ion beam, consisting primarily of protons, passing through an H/sub 2/ gas cell neutralizer. Plasma ions (or ion-electron pairs) are produced by electron capture from (or ionization of) gas molecules by beam ions and atoms. An explanation is provided for the observed anomalous behavior of the electron temperature (T/sub e/): a step-lite, nearly two-fold jump in T/sub e/ as the beam current approaches that which minimizes beam angular divergence; insensitivity of T/sub e/ to gas pressure; and the linear relation of T/sub e/ to beam energy.

Guethlein, G.

1987-04-01T23:59:59.000Z

282

A very low energy compact electron beam ion trap for spectroscopic research in Shanghai  

Science Conference Proceedings (OSTI)

In this paper, a new compact low energy electron beam ion trap, SH-PermEBIT, is reported. This electron beam ion trap (EBIT) can operate in the electron energy range of 60-5000 eV, with a current density of up to 100 A/cm{sup 2}. The low energy limit of this machine sets the record among the reported works so far. The magnetic field in the central drift tube region of this EBIT is around 0.5 T, produced by permanent magnets and soft iron. The design of this EBIT allows adjustment of the electron gun's axial position in the fringe field of the central magnetic field. This turned out to be very important for optimizing the magnetic field in the region of the electron gun and particularly important for low electron beam energy operation, since the magnetic field strength is not tunable with permanent magnets. In this work, transmission of the electron beam as well as the upper limit of the electron beam width under several conditions are measured. Spectral results from test operation of this EBIT at the electron energies of 60, 315, 2800, and 4100 eV are also reported.

Xiao, J.; Fei, Z.; Yang, Y.; Jin, X.; Lu, D.; Shen, Y.; Hutton, R.; Zou, Y. [The Key lab of Applied Ion Beam Physics, Ministry of Education, Shanghai (China); Shanghai EBIT lab, Institute of Modern Physics, Fudan University, Shanghai (China); Liljeby, L. [Manne Siegbahn Laboratory, Stockholm University, Stockholm (Sweden)

2012-01-15T23:59:59.000Z

283

Three-dimensional fabrication and characterisation of core-shell nano-columns using electron beam patterning of Ge-doped SiO{sub 2}  

Science Conference Proceedings (OSTI)

A focused electron beam in a scanning transmission electron microscope (STEM) is used to create arrays of core-shell structures in a specimen of amorphous SiO{sub 2} doped with Ge. The same electron microscope is then used to measure the changes that occurred in the specimen in three dimensions using electron tomography. The results show that transformations in insulators that have been subjected to intense irradiation using charged particles can be studied directly in three dimensions. The fabricated structures include core-shell nano-columns, sputtered regions, voids, and clusters.

Gontard, Lionel C. [Instituto de Ciencia de Materiales de Sevilla (CSIC), 41092 Sevilla (Spain); Jinschek, Joerg R. [FEI Europe, Achtseweg Noord 5, 5600 KA Eindhoven (Netherlands); Ou Haiyan [Department of Photonics, Technical University of Denmark, DK-2800 Kongens Lyngby (Denmark); Verbeeck, Jo [EMAT, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Dunin-Borkowski, Rafal E. [Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Gruenberg Institute, Forschungszentrum Juelich, D-52425 Juelich (Germany)

2012-06-25T23:59:59.000Z

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

Electron cloud effects on an intense ion beam in a four solenoid lattice  

E-Print Network (OSTI)

beam in a four solenoid lattice J.E. Coleman Department ofbeam in a two-solenoid lattice. Initial experiments showed aadded to the two-solenoid lattice in order to study electron

2008-01-01T23:59:59.000Z

286

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

Science Conference Proceedings (OSTI)

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

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

2010-06-01T23:59:59.000Z

287

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

E-Print Network (OSTI)

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

Zhang, Feng, 1973-

2005-01-01T23:59:59.000Z

288

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

E-Print Network (OSTI)

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

289

EXPERIMENTAL STUDY OF ENERGY SPREAD IN A SPACE-CHARGE DOMINATED ELECTRON BEAM *  

E-Print Network (OSTI)

energy from the gun. It is believed that this DC energy shift is due to the use of mesh and focusingEXPERIMENTAL STUDY OF ENERGY SPREAD IN A SPACE-CHARGE DOMINATED ELECTRON BEAM * Y. Cui , Y. Zou, A Physics, University of Maryland, College Park, Maryland 20742 Abstract Characterization of beam energy

Valfells, ÁgĂșst

290

Fabrication of single electron transistors in multi-wall carbon nanotubes using Ar beam irradiation  

Science Conference Proceedings (OSTI)

The Ar beam with an acceleration voltage of 300 V has been irradiated to multi-wall carbon nanotubes (MWNTs) through a narrow opening of the resist, in order to form a tunnel barrier. The tunnel resistance could be set by appropriate dose, in the range ... Keywords: Ar beam, carbon nanotubes, coulomb blockade, quantum dots, single electron transistor

K. Ishibashi; M. Suzuki; D. Tsuya; Y. Aoyagi

2003-06-01T23:59:59.000Z

291

Low emittance electron beam production and characterization with a 17 GHz photocathode RF gun  

E-Print Network (OSTI)

This thesis presents theoretical and experimental results of the production of very high brightness electron beams using a 17 GHz photocathode RF gun. A beam brightness of up to 8x 1013 A/([pi]m rad)2 was measured for a 1 ...

Brown, Winthrop Joseph

2001-01-01T23:59:59.000Z

292

Overview of Phase Space Manipulations of Relativistic Electron Beams  

SciTech Connect

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

Xiang, Dao; /SLAC

2012-08-31T23:59:59.000Z

293

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

294

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

295

650 mm long liquid hydrogen target for use in a high intensity electron beam  

DOE Green Energy (OSTI)

This paper describes a 650 mm long liquid hydrogen targetr constructed for use in the high intensity electron beam at the Stanford Linear Accelerator Center (SLAC). The main design problem was to construct a target that would permit the heat deposited by the electron beam to be removed rapidly without boiling the hydrogen so as to maintain constant target density for optimum data taking. Design requirements, cosntruction details and operating experience are discussed.

Mark, J.W.

1984-02-01T23:59:59.000Z

296

650 mm long liquid hydrogen target for use in a high intensity electron beam  

DOE Green Energy (OSTI)

This paper describes a 650 mm long liquid hydrogen target constructed for use in the high intensity electron beam at the Stanford Linear Accelerator Center. The main design problem was to construct a target that would permit the heat deposited by the electron beam to be removed rapidly without boiling the hydrogen so as to maintain constant target density for optimum data taking. Design requirements, construction details and operating experience are discussed.

Mark, J.W.

1983-07-01T23:59:59.000Z

297

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

298

EXTRACTION OF HIGHLY CHARGED AU IONS FROM A MULTIAMPHERE ELECTRON BEAM EBIS AT BNL.  

DOE Green Energy (OSTI)

Excellent progress has been made in the operation of the BNL Electron Beam Ion Source (EBIS), which is a prototype for an EBIS that could meet requirements for a RHIC preinjector. We have achieved very stable operation of the electron beam at 10 A through the EBIS trap. Ion injection of low charge gold ions from a LEVA [1] ion source and subsequent extraction of these ions with most probable charge state AU{sup 34+} has been demonstrated with electron beams up to 8A. The total ion charge for gold measured on current transformer at the EBIS exit was 55nC after a 30ms confinement period. This corresponds to {approx}85% of the theoretical ion trap capacity and exceeds our goal of 50% neutralization. The collected ion charge is proportional to the electron current and the gold charge state scales with the electron current density. Details of the EBIS configuration, total charge measurements, and TOF spectra are given.

BEEBE,E.N.; ALESSI,J.G.; GOULD,O.; GRAHAM,D.; KPONOU,A.; PIKIN,A.; PRELEC,K.; RITTER,J.

2001-09-02T23:59:59.000Z

299

Submillimeter-Resolution Radiography of Shielded Structures with Laser-Accelerated Electron Beams  

SciTech Connect

We investigate the use of energetic electron beams for high-resolution radiography of flaws embedded in thick solid objects. A bright, monoenergetic electron beam (with energy >100 MeV) was generated by the process of laser-wakefield acceleration through the interaction of 50-TW, 30-fs laser pulses with a supersonic helium jet. The high energy, low divergence, and small source size of these beams make them ideal for high-resolution radiographic studies of cracks or voids embedded in dense materials that are placed at a large distance from the source. We report radiographic imaging of steel with submillimeter resolution.

Ramanathan, Vidya [University of Nebraska, Lincoln; Banerjee, Sudeep [University of Nebraska, Lincoln; Powell, Nathan [University of Nebraska, Lincoln; Cummingham, N. J. [University of Nebraska, Lincoln; Chandler-Smith, Nate [University of Nebraska, Lincoln; Zhao, Kun [University of Nebraska, Lincoln; Brown, Kevin [University of Nebraska, Lincoln; Umstadter, Donald [University of Nebraska, Lincoln; Clarke, Shaun [University of Michigan; Pozzi, Sara [University of Michigan; Beene, James R [ORNL; Vane, C Randy [ORNL; Schultz, David Robert [ORNL

2010-10-01T23:59:59.000Z

300

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

Science Conference Proceedings (OSTI)

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 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

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

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

SciTech Connect

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

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

2013-11-01T23:59:59.000Z

302

In situ nanomechanical testing in focused ion beam and scanning electron microscopes  

Science Conference Proceedings (OSTI)

The recent interest in size-dependent deformation of micro- and nanoscale materials has paralleled both technological miniaturization and advancements in imaging and small-scale mechanical testing methods. Here we describe a quantitative in situ nanomechanical testing approach adapted to a dual-beam focused ion beam and scanning electron microscope. A transducer based on a three-plate capacitor system is used for high-fidelity force and displacement measurements. Specimen manipulation, transfer, and alignment are performed using a manipulator, independently controlled positioners, and the focused ion beam. Gripping of specimens is achieved using electron-beam assisted Pt-organic deposition. Local strain measurements are obtained using digital image correlation of electron images taken during testing. Examples showing results for tensile testing of single-crystalline metallic nanowires and compression of nanoporous Au pillars will be presented in the context of size effects on mechanical behavior and highlight some of the challenges of conducting nanomechanical testing in vacuum environments.

Gianola, D. S. [Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Institute for Applied Materials, Karlsruhe Institute of Technology, Karlsruhe (Germany); Sedlmayr, A.; Moenig, R.; Kraft, O. [Institute for Applied Materials, Karlsruhe Institute of Technology, Karlsruhe (Germany); Volkert, C. A. [Institute for Materials Physics, Georg-August University of Goettingen, Goettingen (Germany); Major, R. C.; Cyrankowski, E.; Asif, S. A. S.; Warren, O. L. [Hysitron, Inc., Minneapolis, Minnesota 55344 (United States)

2011-06-15T23:59:59.000Z

303

Two-particle picture and electronic structure calculations  

SciTech Connect

We derive exact formal expressions for the self-energy, (capital Sigma (n), describing the in- teraction of n particles with one another and with the rest of the particles in an interacting quantum N-particle system In contrast to traditional treatments, in which the single-particle self-energy is built out of interactions of a particle with the rest of the system, here a general n-particle quantity, (capital sigma)(n), is obtained in a straight- forward fashion by integrating the exact N-particle Green function, G(N), over the coordinates of N _ n particles and inverting An alternative expression, based on the canonical many-body equation of motion for the Green function is also discussed and compared with that derived through the integration process. The methodology is developed with respect to two-particle states, with the two-particle Green function being the central quantity from which the single-particle self-energy and Green function are derived It is suggested that the two-particle Green function be calculated directly in six-dimensional space in a two-particle generalization of density functional theory and the corresponding local density approximation. Methods for the calculation of the single-particle, n = 1, self-energy and effective single-particle t-matrix are discussed, and the methodology is illustrated by means of calculations on a model system.

Gonis, A; Schulthess, T C; Turchi, P E A

1998-06-24T23:59:59.000Z

304

Uranium-contaminated soils: Ultramicrotomy and electron beam analysis  

Science Conference Proceedings (OSTI)

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

305

A stochastic kinematic model of class averaging in single-particle electron microscopy  

Science Conference Proceedings (OSTI)

Single-particle electron microscopy is an experimental technique that is used to determine the three-dimensional (3D) structure of biological macromolecules and the complexes that they form. In general, image processing techniques and reconstruction ... Keywords: Class average, convolution, image alignment, single-particle electron microscopy

Wooram Park; Charles R Midgett; Dean R Madden; Gregory S Chirikjian

2011-05-01T23:59:59.000Z

306

Operation of a large GEM-MSGC detector in a high intensity hadronic test beam using fully pipelined readout electronics  

E-Print Network (OSTI)

98-060 In a recent test beam experiment at PSI a new tracking device for very high particle fluxes consisting of a low gain micro strip gas chamber (MSGC) combined with a gas electron multiplier (GEM) foil has been run under beam conditions similar to those foreseen in the HERA-B experiment [1], where such devices are being installed for the inner tracker. They are also being evaluated for the LHCb experiment [2]. In both detectors very high, mainly hadronic particle densities (up to 10 4 mm -2 sec -1) are expected, while the momentum resolution of the magnetic spectrometers foreseen in the two experiments is limited by multiple scattering. Also photon conversions represent a significant background source and therefore a minimal thickness in terms of radiation length is important, while position resolution requirements are moderate (typically 300 mu m pitch is sufficient). This paper describes the detailed construction of this novel detector, the test beam configuration and some of the data taken using the fu...

Eisele, F; Straumann, U; Straumann, Ulrich

1998-01-01T23:59:59.000Z

307

Controlling helicity-correlated beam asymmetries in a polarized electron source  

Science Conference Proceedings (OSTI)

The control of helicity-correlated changes in the electron beam is a critical issue for the next generation of parity-violating electron scattering measurements. The underlying causes and methods for controlling these changes are reviewed with reference to recent operational experience at Jefferson Lab.

Kent Paschke

2007-07-01T23:59:59.000Z

308

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

309

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

SciTech Connect

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.

Lasche, George P. (Arlington, VA)

1988-01-01T23:59:59.000Z

310

Observation of Shot Noise Suppression at Optical Wavelengths in a Relativistic Electron Beam  

Science Conference Proceedings (OSTI)

Control of collective properties of relativistic particles is increasingly important in modern accelerators. In particular, shot noise affects accelerator performance by driving instabilities or by competing with coherent processes. We present experimental observations of shot noise suppression in a relativistic beam at the Linac Coherent Light Source. By adjusting the dispersive strength of a chicane, we observe a decrease in the optical transition radiation emitted from a downstream foil. We show agreement between the experimental results, theoretical models, and 3D particle simulations.

Ratner, Daniel; Stupakov, Gennady; /SLAC

2012-06-19T23:59:59.000Z

311

Optical and x-ray imaging of electron beams using synchrotron emission  

SciTech Connect

In the case of very low eniittance electron and positron storage ring beams, it is impossible to make intrusive measurements of beam properties without increasing the emittance and possibly disrupting the beam. In cases where electron or positron beams have high average power densities (such as free electron laser linacs), intrusive probes such as wires and optical transition radiation screens or Cherenkov emitting screens can be easily damaged or destroyed. The optical and x-ray emissions from the bends in the storage rings and often from linac bending magnets can be used to image the beam profile to obtain emittance information about the beam. The techniques, advantages and limitations of using both optical and x-ray synchrotron emission to measure beam properties are discussed and the possibility of single bunch imaging is considered. The properties of suitable imagers and converters such as phosphors are described. Examples of previous, existing and planned applications are given where available, including a pinhole imaging system currently being designed for the Advanced Photon Source at Argonne National Laboratory.

Wilke, M.D.

1994-12-01T23:59:59.000Z

312

Thermodynamic Bounds on Nonlinear Electrostatic Perturbations in Intense Charged Particle Beams  

Science Conference Proceedings (OSTI)

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? 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

313

The Nike electron-beam-pumped KrF laser amplifiers  

SciTech Connect

Nike is a recently completed multikilojoule krypton-fluoride (KrF) laser that has been built to study the physics of direct-drive inertial confinement fusion. The two final amplifiers of the Nike laser are both electron-beam-pumped systems. This paper describes these two amplifiers, with an emphasis on the pulsed power. The smaller of the two has a 20 x 20 cm aperture, and produces an output laser beam energy in excess of 100 J. This 20 cm Amplifier uses a single 12 kJ Marx generator to inject two 300 kV, 75 kA, 140 ns flat-top electron beams into opposite sides of the laser cell. The larger amplifier in Nike has a 60 x 60 cm aperture, and amplifies the laser beam up to 5 kJ. This 60 cm amplifier has two independent electron beam systems. Each system has a 170 kJ Marx generator that produces a 670 kV, 540 kA, 240 ns flat-top electron beam. Both amplifiers are complete, fully integrated into the laser, meet the Nike system requirements, and are used routinely for laser-target experiments.

Sethian, J.D.; Pawley, C.J.; Obenschain, S.P. [Naval Research Lab., Washington, DC (United States). Plasma Physics Div.] [and others

1997-04-01T23:59:59.000Z

314

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

SciTech Connect

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

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

2012-06-15T23:59:59.000Z

315

SELF-CONSISTENT LANGEVIN SIMULATION OF COULOMB COLLISIONS IN CHARGED-PARTICLE BEAMS  

SciTech Connect

In many plasma physics and charged-particle beam dynamics problems, Coulomb collisions are modeled by a Fokker-Planck equation. In order to incorporate these collisions, we present a three-dimensional parallel Langevin simulation method using a Particle-In-Cell (PIC) approach implemented on high-performance parallel computers. We perform, for the first time, a fully self-consistent simulation, in which the friction and diffusion coefficients are computed from first principles. We employ a two-dimensional domain decomposition approach within a message passing programming paradigm along with dynamic load balancing. Object oriented programming is used to encapsulate details of the communication syntax as well as to enhance reusability and extensibility. Performance tests on the SGI Origin 2000 and the Cray T3E-900 have demonstrated good scalability. Work is in progress to apply our technique to intrabeam scattering in accelerators.

J. QIANG; R. RYNE; S. HABIB

2000-05-01T23:59:59.000Z

316

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

Science Conference Proceedings (OSTI)

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

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

1997-12-01T23:59:59.000Z

317

Electro-optic techniques in electron beam diagnostics  

Science Conference Proceedings (OSTI)

Electron accelerators such as laser wakefield accelerators, linear accelerators driving free electron lasers, or femto-sliced synchrotrons, are capable of producing femtosecond-long electron bunches. Single-shot characterization of the temporal charge profile is crucial for operation, optimization, and application of such accelerators. A variety of electro-optic sampling (EOS) techniques exists for the temporal analysis. In EOS, the field profile from the electron bunch (or the field profile from its coherent radiation) will be transferred onto a laser pulse co-propagating through an electro-optic crystal. This paper will address the most common EOS schemes and will list their advantages and limitations. Strong points that all techniques share are the ultra-short time resolution (tens of femtoseconds) and the single-shot capabilities. Besides introducing the theory behind EOS, data from various research groups is presented for each technique.

van Tilborg, Jeroen; Toth, Csaba; Matlis, Nicholas; Plateau, Guillaume; Leemans, Wim

2011-06-17T23:59:59.000Z

318

Uranium-contaminated soils: Ultramicrotomy and electron beam analysis  

Science Conference Proceedings (OSTI)

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

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

1994-02-01T23:59:59.000Z

319

Cerenkov and cyclotron Cerenkov instabilities in a dielectric loaded parallel plate waveguide sheet electron beam system  

SciTech Connect

A dielectric loaded parallel plate waveguide sheet electron beam system can be taken as a reliable model for the practical dielectric loaded rectangular waveguide sheet beam system that has a transverse cross section with a large width to height ratio. By using kinetic theory, the dispersion equations for Cerenkov and cyclotron Cerenkov instabilities in the parallel plate waveguide sheet beam system have been obtained rigorously. The dependences of the growth rate of both instabilities on the electric and structural parameters have also been investigated in detail through numerical calculations. It is worthwhile to point out that adopting an electron beam with transverse velocity can evidently improve the growth rate of Cerenkov instability, which seems like the case of cyclotron Cerenkov instability.

Zhao Ding; Ding Yaogen [Key Laboratory of High Power Microwave Sources and Technologies, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190 (China)

2011-09-15T23:59:59.000Z

320

USE OF INCIDENT AND REFLECTED SOLAR PARTICLE BEAMS TO TRACE THE TOPOLOGY OF MAGNETIC CLOUDS  

SciTech Connect

Occasionally, large solar energetic particle (SEP) events occur inside magnetic clouds (MCs). In this work, the onset time analysis, the peak intensity analysis, and the decay phase analysis of SEPs are used to investigate two large SEP events inside MCs: the 1998 May 2 and 2002 April 21 events. The onset time analysis of non-relativistic electrons and {approx}MeV nucleon{sup -1} heavy ions shows the stability of the magnetic loop structure during a period of a few hours in the events examined. The joint analysis of pitch-angle distributions and peak intensities of electrons exhibits that, depending on the particle pitch angle observed at 1 AU, in the April event the reflection point of particles may be distributed along a wide spatial range, implying that the magnetic loop is a magnetic bottle connected to the Sun with both legs. In contrast, in the May event particle reflection occurs abruptly at the magnetic mirror formed by a compressed field enhancement behind the interplanetary shock, consistent with its open field line topology.

Tan, Lun C. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Malandraki, Olga E.; Dorrian, Gareth [Institute of Astronomy and Astrophysics, National Observatory of Athens (Greece); Reames, Donald V. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States); Ng, Chee K. [College of Science, George Mason University, Fairfax, VA 22030 (United States); Wang Linghua, E-mail: ltan@umd.edu [Space Science Laboratory, University of California, Berkeley, CA 94720 (United States)

2012-05-10T23:59:59.000Z

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.


321

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

322

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

Science Conference Proceedings (OSTI)

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

323

Electron beam and plasma modes of a channel spark discharge operation  

SciTech Connect

Parameters of a modified pulsed channel spark discharge (CSD), operating at a repetition rate up to 100 Hz at Ar gas pressures of 10{sup -3} and 10{sup -4} Torr and of the generated electron beam, were studied using different electrical, optical, and x-ray diagnostics. It was shown that efficient (up to approx74%) transfer of the initially stored energy to the energetic electron beam is realized only at the pressure of 10{sup -4} Torr. Conversely, at the pressure of 10{sup -3} Torr, less than 10% of the stored energy is acquired by the energetic electrons. It was found that the energetic electron beam generation is limited by the expansion of the cathode and anode plasmas and by the formation of plasma inside the gap between the CSD capillary output and the anode. It was also found that the plasma, which acquires the hollow cathode potential, is already formed at the beginning of the CSD operation inside the capillary, and the electron emission occurs from the capillary output plasma boundary. Finally, it was shown that the electron beam energy spectrum differs significantly from the energy spectrum, which one may expect in the case of the planar diode operation.

Gleizer, S.; Yarmolich, D.; Felsteiner, J.; Krasik, Ya. E. [Department of Physics, Technion, 32000 Haifa (Israel); Nozar, P. [Istituto per lo Studio dei Materiali Nanostrutturati, 40129 Bologna (Italy); Taliani, C. [Organic Spintronics, Srl, 40129 Bologna (Italy)

2009-10-01T23:59:59.000Z

324

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

SciTech Connect

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

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

2012-09-26T23:59:59.000Z

325

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

326

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

SciTech Connect

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

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

1981-01-01T23:59:59.000Z

327

Calculation of synchrotron radiation from high intensity electron beam at eRHIC  

Science Conference Proceedings (OSTI)

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

328

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

329

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

330

The use of intensity-modulated radiation therapy photon beams for improving the dose uniformity of electron beams shaped with MLC  

Science Conference Proceedings (OSTI)

Electrons are ideal for treating shallow tumors and sparing adjacent normal tissue. Conventionally, electron beams are collimated by cut-outs that are time-consuming to make and difficult to adapt to tumor shape throughout the course of treatment. We propose that electron cut-outs can be replaced using photon multileaf collimator (MLC). Two major problems of this approach are that the scattering of electrons causes penumbra widening because of a large air gap, and available commercial treatment planning systems (TPSs) do not support MLC-collimated electron beams. In this study, these difficulties were overcome by (1) modeling electron beams collimated by photon MLC for a commercial TPS, and (2) developing a technique to reduce electron beam penumbra by adding low-energy intensity-modulated radiation therapy (IMRT) photons (4 MV). We used blocks to simulate MLC shielding in the TPS. Inverse planning was used to optimize boost photon beams. This technique was applied to a parotid and a central nervous system (CNS) clinical case. Combined photon and electron plans were compared with conventional plans and verified using ion chamber, film, and a 2D diode array. Our studies showed that the beam penumbra for mixed beams with 90 cm source to surface distance (SSD) is comparable with electron applicators and cut-outs at 100 cm SSD. Our mixed-beam technique yielded more uniform dose to the planning target volume and lower doses to various organs at risk for both parotid and CNS clinical cases. The plans were verified with measurements, with more than 95% points passing the gamma criteria of 5% in dose difference and 5 mm for distance to agreement. In conclusion, the study has demonstrated the feasibility and potential advantage of using photon MLC to collimate electron beams with boost photon IMRT fields.

Mosalaei, Homeira, E-mail: homeira.mosalaei@lhsc.on.ca [London Regional Cancer Program, London Health Science Centre, Ontario (Canada); Karnas, Scott [London Regional Cancer Program, London Health Science Centre, Ontario (Canada); University of Waterloo, Waterloo, Ontario (Canada); Shah, Sheel [University of Western Ontario, London, Ontario (Canada); Van Doodewaard, Sharon [McMaster University, Hamilton, Ontario (Canada); Foster, Tim [University of Western Ontario, London, Ontario (Canada); Chen, Jeff [London Regional Cancer Program, London Health Science Centre, Ontario (Canada); University of Waterloo, Waterloo, Ontario (Canada)

2012-04-01T23:59:59.000Z

331

Microring resonators fabricated by electron beam bleaching of chromophore doped polymers  

SciTech Connect

Decomposition of chromophore molecules under direct electron beam irradiation reduces the refractive index of chromophore containing polymers. The induced refractive index contrast between the exposed and unexposed regions is high enough for waveguide bends of small radius and thus microring resonator devices. This electron beam bleaching of chromophore-containing polymers provides a fabrication approach for nonlinear polymer optical waveguide devices. Fabrication of high quality microring resonators with critical feature size on the order of 100 nm was demonstrated with this technique in an electro-optic polymer that contains YL124 chromophores.

Sun Haishan [Department of Electrical Engineering, University of Washington, Seattle, Washington 98195 (United States); Chen Antao [Department of Electrical Engineering, University of Washington, Seattle, Washington 98195 (United States); Applied Physics Laboratory, University of Washington, Seattle, Washington 98105 (United States); Olbricht, Benjamin C.; Davies, Joshua A.; Sullivan, Philip A. [Department of Chemistry, University of Washington, Seattle, Washington 98195 (United States); Liao Yi [Department of Chemistry, University of Central Florida, Orlando, Florida 32816 (United States); Dalton, Larry R. [Department of Electrical Engineering, University of Washington, Seattle, Washington 98195 (United States); Department of Chemistry, University of Washington, Seattle, Washington 98195 (United States)

2008-05-12T23:59:59.000Z

332

0.22 THz wideband sheet electron beam traveling wave tube amplifier: Cold test measurements and beam wave interaction analysis  

Science Conference Proceedings (OSTI)

In this paper, we describe micro-fabrication, RF measurements, and particle-in-cell (PIC) simulation modeling analysis of the 0.22 THz double-vane half period staggered traveling wave tube amplifier (TWTA) circuit. The TWTA slow wave structure comprised of two sections separated by two sever ports loaded by loss material, with integrated broadband input/output couplers. The micro-metallic structures were fabricated using nano-CNC milling and diffusion bonded in a three layer process. The 3D optical microscopy and SEM analysis showed that the fabrication error was within 2-3 {mu}m and surface roughness was measured within 30-50 nm. The RF measurements were conducted with an Agilent PNA-X network analyzer employing WR5.1 T/R modules with a frequency range of 178-228 GHz. The in-band insertion loss (S{sub 21}) for both the short section and long section (separated by a sever) was measured as {approx}-5 dB while the return loss was generally around {approx}-15 dB or better. The measurements matched well with the S-matrix simulation analysis that predicted a 3 dB bandwidth of {approx}45 GHz with an operating frequency at 220 GHz. However, the measured S{sub 21} was {approx}3 dB less than the design values, and is attributed to surface roughness and alignment issues. The confirmation measurements were conducted over the full frequency band up to 270 GHz employing a backward wave oscillator (BWO) scalar network analyzer setup employing a BWO in the frequency range 190 GHz-270 GHz. PIC simulations were conducted for the realistic TWT output power performance analysis with incorporation of corner radius of 127 {mu}m, which is inevitably induced by nano-machining. Furthermore, the S{sub 21} value in both sections of the TWT structure was reduced to correspond to the measurements by using a degraded conductivity of 10% International Annealed Copper Standard. At 220 GHz, for an elliptic sheet electron beam of 20 kV and 0.25 A, the average output power of the tube was predicted to be reduced from 90 W (for ideal conductivity/design S-parameters) to 70 W (for the measured S-parameters/inferred conductivity) for an average input power of 50 mW. The gain of the tube remains reasonable: {approx}31.4 dB with an electronic efficiency of {approx}1.4%. The same analysis was also conducted for several frequencies between 190 GHz-260 GHz. This detailed realistic PIC analysis demonstrated that this nano-machined TWT circuit has slightly reduced S-parameters and output power from design, but within an acceptable range and still have promising output power, gain, and band width as required. Thus, we expect to meet the specifications of 1000 W-GHz for the darpa program goals.

Baig, Anisullah; Gamzina, Diana; Barchfeld, Robert; Domier, Calvin; Barnett, Larry R.; Luhmann, Neville C. Jr. [Department of Electrical and Computer Engineering, University of California, Davis, California 95616 (United States)

2012-09-15T23:59:59.000Z

333

Coupled force-balance and particle-occupation rate equations for high-field electron transport  

SciTech Connect

It is pointed out that in the framework of balance-equation approach, the coupled force-balance and particle-occupation rate equations can be used as a complete set of equations to determine the high-field transport of semiconductors in both strong and weak electron-electron interaction limits. We call to attention that the occupation rate equation conserves the total particle number and maintains the energy balance of the relative electron system, and there is no need to introduce any other term in it. The addition of an energy-drift term in the particle-occupation rate equation [Phys. Rev. B 71, 195205 (2005)] is physically inadequate for the violation of the total particle-number conservation and the energy balance. It may lead to a substantial unphysical increase of the total particle number by the application of a dc electric field.

Lei, X. L. [Department of Physics, Shanghai Jiaotong University, 1954 Huashan Road, Shanghai 200030 (China)

2008-01-15T23:59:59.000Z

334

Low energy electron beam induced vacancy activation in GaN  

Science Conference Proceedings (OSTI)

Experimental evidence on low energy electron beam induced point defect activation in GaN grown by metal-organic vapor phase epitaxy (MOVPE) is presented. The GaN samples are irradiated with a 5-20 keV electron beam of a scanning electron microscope and investigated by photoluminescence and positron annihilation spectroscopy measurements. The degradation of the band-to-band luminescence of the irradiated GaN films is associated with the activation of point defects. The activated defects were identified as in-grown Ga-vacancies. We propose that MOVPE-GaN contains a significant concentration of passive V{sub Ga}-H{sub n} complexes that can be activated by H removal during low energy electron irradiation.

Nykaenen, H.; Suihkonen, S.; Sopanen, M. [Department of Micro- and Nanosciences, Aalto University, P.O. Box 13500, FI-00076 Aalto (Finland); Kilanski, L. [Department of Applied Physics, Aalto University, P.O. Box 11100, FI-00076 Aalto (Finland); Institute of Physics, Polish Academy of Sciences, Al. Lotnikow 32/56, 02-668 Warsaw (Poland); Tuomisto, F. [Department of Applied Physics, Aalto University, P.O. Box 11100, FI-00076 Aalto (Finland)

2012-03-19T23:59:59.000Z

335

High resolution low dose transmission electron microscopy real-time imaging and manipulation of nano-scale objects in the electron beam  

DOE Patents (OSTI)

The present invention includes a method, apparatus and system for nanofabrication in which one or more target molecules are identified for manipulation with an electron beam and the one or more target molecules are manipulated with the electron beam to produce new useful materials.

Brown, Jr., R. Malcolm (Austin, TX); Barnes, Zack (Austin, TX); Sawatari, Chie (Shizuoka, JP); Kondo, Tetsuo (Kukuoka, JP)

2008-02-26T23:59:59.000Z

336

Electron acceleration by a tightly focused Hermite-Gaussian beam: higher-order corrections  

SciTech Connect

Taking the TEM{sub 1,0}-mode Hermite-Gaussian (H-G) beam as a numerical calculation example, and based on the method of the perturbation series expansion, the higher-order field corrections of H-G beams are derived and used to study the electron acceleration by a tightly focused H-G beam in vacuum. For the case of the off-axis injection the field corrections to the terms of order f{sup 3} (f=1/kw{sub 0}, k and w{sub 0} being the wavenumber and waist width, respectively) are considered, and for the case of the on-axis injection the contributions of the terms of higher orders are negligible. By a suitable optimization of injection parameters the energy gain in the giga-electron-volt regime can be achieved.

Zhao Zhiguo [Department of Physics, Luoyang Normal College, Luoyang 471022 (China); Institute of Laser Physics and Chemistry, Sichuan University, Chengdu 610064 (China); Yang Dangxiao; Lue Baida [Institute of Laser Physics and Chemistry, Sichuan University, Chengdu 610064 (China)

2008-03-15T23:59:59.000Z

337

Absolute Current Calibrations of 1muA CW Electron Beam  

SciTech Connect

The future experimental program at Jefferson Lab requires an absolute current calibration of a 1{mu}A CW electron beam to better than 1% accuracy. This paper presents the mechanical and electrical design of a Tungsten calorimeter that is being constructed to provide an accurate measurement of the deposited energy. The energy is determined by measuring the change in temperature after beam exposure. Knowledge of the beam energy then yields number of electrons stopped by the calorimeter during the exposure. Simulations show that the energy losses due to electromagnetic and hadronic losses are the dominant uncertainty. Details of the precision thermometry and calibration, mechanical design, thermal simulations and GEANT simulations will be presented.

A. Freyberger, M.E. Bevins, A.R. Day, P. Degtiarenko, A. Saha, S. Slachtouski, R. Gilman

2005-06-06T23:59:59.000Z

338

Collisional stochastic ripple diffusion of alpha particles and beam ions on TFTR  

Science Conference Proceedings (OSTI)

Predictions for ripple loss of fast ions from TFTR are investigated with a guiding center code including both collisional and ripple effects. A synergistic enhancement of fast ion diffusion is found for toroidal field ripple with collisions. The total loss is calculated to be roughly twice the sum of ripple and collisional losses calculated separately. Discrepancies between measurements and calculations of plasma beta at low current and large major radius are resolved when both effects are included for neutral beam ions. A 20--30% reduction in alpha particle heating is predicted for q{sub a} = 6--14, R = 2.6 m DT plasmas on TFTR due to first orbit and collisional stochastic ripple diffusion.

Redi, M.H.; Zarnstorff, M.C.; White, R.B.; Budny, R.V.; Janos, A.C.; Owens, D.K.; Schivell, J.F.; Scott, S.D.; Zweben, S.J.

1995-07-01T23:59:59.000Z

339

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

340

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

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

Micro-cone targets for producing high energy and low divergence particle beams  

DOE Patents (OSTI)

The present invention relates to micro-cone targets for producing high energy and low divergence particle beams. In one embodiment, the micro-cone target includes a substantially cone-shaped body including an outer surface, an inner surface, a generally flat and round, open-ended base, and a tip defining an apex. The cone-shaped body tapers along its length from the generally flat and round, open-ended base to the tip defining the apex. In addition, the outer surface and the inner surface connect the base to the tip, and the tip curves inwardly to define an outer surface that is concave, which is bounded by a rim formed at a juncture where the outer surface meets the tip.

Le Galloudec, Nathalie

2013-09-10T23:59:59.000Z

342

Study of the TESLA preaccelerator for the polarised electron beam Aline Curtoni, Marcel Jablonka,  

E-Print Network (OSTI)

Study of the TESLA preaccelerator for the polarised electron beam Aline Curtoni, Marcel Jablonka, CEA, DSM/DAPNIA, Saclay, France Abstract In the mainframe of the TESLA Technical Design Report a study assumed. Figure 1 : Schematic of the TESLA injector complex. This report deals with the bottom injector

343

PtRu/C electrocatalysts prepared using gamma and electron beam irradiation for methanol electrooxidation  

Science Conference Proceedings (OSTI)

PtRu/C electrocatalysts (carbon-supported PtRu nanoparticles) were prepared in a single step submitting water/2-propanol mixtures containing Pt(IV) and Ru(III) ions and the carbon support to gamma and electron beam irradiation. The electrocatalysts were ...

Dionisio F. Silva, Adriana N. Geraldes, Eddy S. Pino, Almir Oliveira Neto, Marcelo Linardi, Estevam V. Spinacé

2012-01-01T23:59:59.000Z

344

Electron beam lithography at 10keV using an epoxy based high resolution negative resist  

Science Conference Proceedings (OSTI)

The behaviour of a new epoxy based resist (mr-EBL 6000.1 XP) as a negative resist for e-beam lithography is presented. We demonstrate that it is possible to define sub-100nm patterns when irradiating thin (120nm) layers of resist with a 10keV electron ... Keywords: EBL, Nanopatterning, Negative resist, Polymer technology

C. Martin; G. Rius; A. Llobera; A. Voigt; G. Gruetzner; F. Pérez-Murano

2007-05-01T23:59:59.000Z

345

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

346

Radio-frequency emission from an explosive instability in an electron beam  

SciTech Connect

The explosive instability which occurs when an electron beam moves through a helical resonator is studied. This instability can be exploited to generate rf oscillations at high efficiency (20% in these experiments). The spectral width is narrower than the characteristic width for linear instabilities.

Buts, V.A.; Izmailov, A.N.

1978-07-01T23:59:59.000Z

347

High-current electron beam generation by a pulsed hollow cathode  

Science Conference Proceedings (OSTI)

In this paper the parameters of a hollow-cathode electron source and the generatedelectron beam are presented. A gas puff valve is used to provide a sharp pressure gradient between the cathode cavity and the accelerating gap. To produce the plasma inside the hollow cathode we used a pulse forming network (10 kV

J. Z. Gleizer; A. Krokhmal; Ya. E. Krasik; J. Felsteiner

2002-01-01T23:59:59.000Z

348

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

Science Conference Proceedings (OSTI)

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

349

Electrostatic solitary structures in presence of non-thermal electrons and a warm electron beam on the auroral field lines  

Science Conference Proceedings (OSTI)

Electrostatic solitary waves (ESWs) have been observed by satellites in the auroral region of the Earth's magnetosphere. These ESWs are found to be having both positive and negative electrostatic potentials. Using the Sagdeeev psuedo-potential technique, arbitrary amplitude electron-acoustic solitary waves/double layers are studied in an unmagnetized plasma consisting of non-thermally distributed hot electrons, fluid cold electrons, a warm electron beam, and ions. The inertia of the warm electrons, and not the beam speed, is essential for the existence of positive potential solitary structures. Existence domains for positive as well as negative potential electrostatic solitons/double layers are obtained. For the typical auroral region parameters, the electric field amplitude of the negative potential solitons is found to be in the range {approx}(3-30) mV/m and {approx}(5-80) mV/m for the positive potential solitons. For the negative potential solitons/double layers, the amplitudes are higher when their widths are smaller. On the other hand, the amplitude of the positive potential structures increase with their widths.

Singh, S. V. [Indian Institute of Geomagnetism, Navi Mumbai (India); School of Physics, University of Kwazulu-Natal, Durban (South Africa); Lakhina, G. S. [Indian Institute of Geomagnetism, Navi Mumbai (India); Bharuthram, R. [University of the Western Cape, Bellville (South Africa); Pillay, S. R. [School of Physics, University of Kwazulu-Natal, Durban (South Africa)

2011-12-15T23:59:59.000Z

350

Excitation of terahertz radiation by an electron beam in a dielectric lined waveguide with rippled dielectric surface  

SciTech Connect

A relativistic electron beam propagating through a dielectric lined waveguide, with ripple on the dielectric surface, excites a free electron laser type instability where ripple acts as a wiggler. The spatial modulation of permittivity in the ripple region couples a terahertz radiation mode to a driven mode of lower phase velocity, where the beam is in Cerenkov resonance with the slow mode. Both the modes grow at the expanse of beam energy. The terahertz frequency increases as the beam velocity increases. The growth rate of the instability goes as one third power of beam density.

Tripathi, Deepak; Uma, R. [Center for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110016 (India); Tripathi, V. K. [Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016 (India)

2012-09-15T23:59:59.000Z

351

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

352

New Electron Beam-Dump Experiments to Search for MeV to few-GeV Dark Matter  

E-Print Network (OSTI)

In a broad class of consistent models, MeV to few-GeV dark matter interacts with ordinary matter through weakly coupled GeV-scale mediators. We show that a suitable meter-scale (or smaller) detector situated downstream of an electron beam-dump can sensitively probe dark matter interacting via sub-GeV mediators, while B-factory searches cover the 1-5 GeV range. Combined, such experiments explore a well-motivated and otherwise inaccessible region of dark matter parameter space with sensitivity several orders of magnitude beyond existing direct detection constraints. These experiments would also probe invisibly decaying new gauge bosons ("dark photons") down to kinetic mixing of \\epsilon ~ 10^{-4}, including the range of parameters relevant for explaining the (g-2)_{\\mu} discrepancy. Sensitivity to other long-lived dark sector states and to new milli-charge particles would also be improved.

Eder Izaguirre; Gordan Krnjaic; Philip Schuster; Natalia Toro

2013-07-24T23:59:59.000Z

353

Effect of self-magnetic fields on the nonlinear dynamics of relativistic electron beam with virtual cathode  

Science Conference Proceedings (OSTI)

The report is devoted to the results of the numerical study of the virtual cathode (VC) formation conditions in the relativistic electron beam (REB) under the influence of the self-magnetic and external axial magnetic fields. The azimuthal instability of the relativistic electron beam leading to the formation of the vortex electron structure in the system was found out. This instability is determined by the influence of the self-magnetic fields of the relativistic electron beam, and it leads to the decrease of the critical value of the electron beam current (current when the non-stationary virtual cathode is formed in the drift space). The typical dependencies of the critical current on the external uniform magnetic field value were discovered. The effect of the beam thickness on the virtual cathode formation conditions was also analyzed.

Hramov, A. E.; Koronovskii, A. A. [Saratov State University, Astrakhanskaja 83, Saratov 410012, Russia Saratov State Technical University, Politechnicheskaja 77, Saratov 410028 (Russian Federation); Kurkin, S. A. [Saratov State University, Astrakhanskaja 83, Saratov 410012 (Russian Federation); Filatova, A. E. [Saratov State Technical University, Politechnicheskaja 77, Saratov 410028 (Russian Federation)

2012-11-15T23:59:59.000Z

354

Excitation of surface plasma waves by an electron beam in a magnetized dusty plasma  

Science Conference Proceedings (OSTI)

An electron beam drives surface plasma waves to instability on a vacuum magnetized dusty plasma interface and in a magnetized dusty plasma cylinder via Cerenkov and fast cyclotron interaction. The dispersion relation of a surface plasma wave has been derived and it has been shown that the phase velocity of waves increases with increase in relative density {delta}(=n{sub i0}/n{sub e0}), where n{sub i0} is the ion plasma density and n{sub e0} is the electron plasma density of negatively charged dust grains. The frequency and the growth rate of the unstable wave instability also increases with {delta}. The growth rate of the instability increases with beam density and scales as the one-third power of the beam density in Cerenkov interaction and is proportional to the square root of beam density in fast cyclotron interaction. The dispersion relation of surface plasma waves has been retrieved from the derived dispersion relation by considering that the beam is absent and there is no dust in the plasma cylinder.

Prakash, Ved; Sharma, Suresh C. [Department of Physics, Maharaja Agrasen Institute of Technology, PSP Area Plot No. 1, Sector 22, Rohini, Delhi 110086 (India)

2009-09-15T23:59:59.000Z

355

Trapping of quantum particles and light beams by switchable potential wells  

E-Print Network (OSTI)

We consider basic dynamical effects in settings based on a pair of local potential traps that may be effectively switched on and off, or suddenly displaced, by means of appropriate control mechanisms, such as the scanning tunneling microscopy (STM) or photo-switchable quantum dots. The same models, based on the linear Schrodinger equation with time-dependent trapping potentials, apply to the description of optical planar systems designed for the switching of trapped light beams. The analysis is carried out in the analytical form, using exact solutions of the Schrodinger equation. The first dynamical problem considered in this work is the retention of a particle released from a trap which was suddenly turned off, while another local trap was switched on at a distance - immediately or with a delay. In this case, we demonstrate that the maximum of the retention rate is achieved at a specific finite value of the strength of the new trap, and at a finite value of the temporal delay, depending on the distance between the two traps. Another ptoblem is retrapping of the bound particle when the addition of the second trap transforms the single-well setting into a double-well potential (DWP). In that case, we find probabilities for the retrapping into the ground or first excited state of the DWP. We also analyze effects entailed by the application of a kick to a bound particle, the most interesting one being a kick-induced transition between the DWP's ground and excited states. In the latter case, the largest transition probability is achieved at particular strength of the kick.

Eduard Sonkin; Boris A. Malomed; Er'el Granot; Avi Marchewka

2010-07-14T23:59:59.000Z

356

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

Science Conference Proceedings (OSTI)

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

Ratner, Daniel; /Stanford U. /SLAC

2012-05-25T23:59:59.000Z

357

Ultra high-gradient energy loss by a pulsed electron beam in a plasma  

SciTech Connect

The plasma wake-field mechanism can be used to couple energy at a high rate from a bunched electron beam into a plasma wave. We will present results from the Fermilab A0 facility where a beam with an initial energy of 14 MeV passes through the plasma to emerge with a much broader energy spread, spanning from a low of 3 MeV to a high of over 20 MeV. Over the 8 cm length of the 10{sup 14} cm{sup -3} plasma, this implies a 140 MeV/m deceleration and 72 MeV/m acceleration gradient.

Nikolai Barov et al.

2001-12-19T23:59:59.000Z

358

Simulation studies for operating electron beam ion trap at very low energy for disentangling edge plasma spectra  

SciTech Connect

Electron beam ion traps (EBITs) are very useful tools for disentanglement studies of atomic processes in plasmas. In order to assist studies on edge plasma spectroscopic diagnostics, a very low energy EBIT, SH-PermEBIT, has been set up at the Shanghai EBIT lab. In this work, simulation studies for factors which hinder an EBIT to operate at very low electron energies were made based on the Tricomp (Field Precision) codes. Longitudinal, transversal, and total kinetic energy distributions were analyzed for all the electron trajectories. Influences from the electron current and electron energy on the energy depression caused by the space charge are discussed. The simulation results show that although the energy depression is most serious along the center of the electron beam, the electrons in the outer part of the beam are more likely to be lost when an EBIT is running at very low energy. Using the simulation results to guide us, we successfully managed to reach the minimum electron beam energy of 60 eV with a beam transmission above 57% for the SH-PermEBIT. Ar and W spectra were measured from the SH-PermEBIT at the apparent electron beam energies (read from the voltage difference between the electron gun cathode and the central drift tube) of 60 eV and 1200 eV, respectively. The spectra are shown in this paper.

Jin Xuelong; Fei Zejie; Xiao Jun; Lu Di; Hutton, Roger; Zou Yaming [Key Lab of Applied Ion Beam Physics, Ministry of Education, China and Shanghai EBIT laboratory, Modern Physics Institute, Fudan University, Shanghai (China)

2012-07-15T23:59:59.000Z

359

Joining Uranium to Aluminum using Electron Beam Welding and an Explosively Clad Niobium Interlayer  

SciTech Connect

A uranium alloy was joined to a high strength aluminum alloy using a commercially pure niobium interlayer. Joining of the Nb interlayer to the aluminum alloy was performed using an explosive welding process, while joining the Nb interlayer to the uranium alloy was performed using an electron beam welding process. Explosive welding was selected to bond the Nb to the aluminum alloy in order to minimize the formation of brittle intermetallic phases. Electron beam welding was selected to join the Nb to the uranium alloy in order to precisely control melting so as to minimize mixing of the two metals. A Modified Faraday Cup (MFC) technique using computer-assisted tomography was employed to determine the power distribution of the electron beam so that the welding parameters could be directly transferred to other welding machines. Optical microscopy, scanning electron microscopy, microhardness, and tensile testing of the welds were used to characterize the resulting joints. This paper presents the welding techniques and processing parameters that were developed to produce high integrity ductile joints between these materials.

Elmer, J W; Terrill, P; Brasher, D; Butler, D

2001-06-12T23:59:59.000Z

360

A multislit transverse-emittance diagnostic for space-charge-dominated electron beams  

Science Conference Proceedings (OSTI)

Jefferson Lab is developing a 10 MeV injector to provide an electron beam for a high-power free-electron laser (FEL). To characterize the transverse phase space of the space-charged-dominated beam produced by this injector, the authors designed an interceptive multislit emittance diagnostic. It incorporates an algorithm for phase-space reconstruction and subsequent calculation of the Twiss parameters and emittance for both transverse directions at an update rate exceeding 1 Hz, a speed that will facilitate the transverse-phase-space matching between the injector and the FEL`s accelerator that is critical for proper operation. This paper describes issues pertaining to the diagnostic`s design. It also discusses the acquisition system, as well as the software algorithm and its implementation in the FEL control system. First results obtained from testing this diagnostic in Jefferson Lab`s Injector Test Stand are also included.

Piot, P.; Song, J.; Li, R. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)] [and others

1997-06-01T23:59:59.000Z

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
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361

Microstructural Properties of Gamma Titanium Aluminide Manufactured by Electron Beam Melting  

SciTech Connect

In recent years, Electron Beam Melting (EBM) has matured as a technology for additive manufacturing of dense metal parts. The parts are built by additive consolidation of thin layers of metal powder using an electron beam. With EBM, it is possible to create parts with geometries too complex to be fabricated by other methods, e.g. fine network structures and internal cavities. The process is run in vacuum, which makes it well suited for materials with a high affinity to oxygen, i.e. . titanium compounds. We present material data from a recently conducted study of how melt strategy affects EBM process for gamma titanium aluminide, Ti-48Al-2Cr-2Nb.The investigation includes microstructural characterization, grain size measurement and tensile testing.

Franzen, Sanna Fager [ARCAM AB; Karlsson, Joakim [ARCAM AB; Dehoff, Ryan R [ORNL; Ackelid, Ulf [ARCAM AB; Rios, Orlando [ORNL; Peter, William H [ORNL

2011-01-01T23:59:59.000Z

362

Production of charm and beauty in e{sup +}e{sup -} with polarized electron beam  

SciTech Connect

The test of the Standard Model through the measurements of Z{sup 0} to fermion couplings can benefit from much enhanced sensitivity by using longitudinally polarized electron beams. This report reviews preliminary electroweak measurements from SLD on heavy quark production at the Z{sup 0}, using 150,000 hadronic Z{sup 0} decays accumulated during the 93-95 runs with high electron beam polarization. The parity violating parameters A{sub b} and A{sub c} of the Zbb and Zcc couplings are measured directly from the left-right forward-backward asymmetries. A measurement of R{sub b} with a lifetime double tag and a summary of the preliminary measurement of A{sub LR} from the 93-95 SLD data are also included in this report.

Su, D.

1995-09-01T23:59:59.000Z

363

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

364

Self Assembly of Nano Metric Metallic Particles for Realization of Photonic and Electronic Nano Transistors  

E-Print Network (OSTI)

Abstract: In this paper, we present the self assembly procedure as well as experimental results of a novel method for constructing well defined arrangements of self assembly metallic nano particles into sophisticated nano structures. The self assembly concept is based on focused ion beam (FIB) technology, where metallic nano particles are self assembled due to implantation of positive gallium ions into the insulating material (e.g., silica as in silicon on insulator wafers) that acts as intermediary layer between the substrate and the negatively charge metallic nanoparticles.

Asaf Shahmoon; Ofer Limon; Olga Girshevitz; Zeev Zalevsky

2010-01-01T23:59:59.000Z

365

Suppression of stimulated Raman scattering due to localization of electron plasma wave in laser beam filaments  

Science Conference Proceedings (OSTI)

The filamentation of the high power laser beam by taking off-axial contribution is investigated when ponderomotive nonlinearity is taken into account. The splitted profile of the laser beam is obtained due to uneven focusing of the off-axial rays. It is observed that the weak electron plasma wave (EPW) propagating in the z direction is nonlinearly coupled in the modified filamentary regions of the laser beam. The semianalytical solution of the nonlinear coupled EPW equation in the presence of laser beam filaments has been found and it is observed that the nonlinear coupling between these two waves leads to localization of the EPW. Stimulated Raman scattering (SRS) of this EPW is studied and backreflectivity has been calculated. Further, the localization of EPW affects the eigenfrequency and damping of plasma wave. As a result of this, mismatch and modified enhanced Landau damping lead to the disruption of SRS process and a substantial reduction in the backreflectivity. For the typical laser beam and plasma parameters with wavelength ({lambda}=1064 nm), power flux ({approx_equal}10{sup 16} W cm{sup -2}), and plasma density (n/n{sub cr})=0.2; the backreflectivity was found to be suppressed by a factor of around 20%.

Sharma, Prerana; Sharma, R. P. [Centre for Energy Studies, Indian Institute of Technology, New Delhi 110016 (India)

2009-03-15T23:59:59.000Z

366

Presentations from ECLOUD10, the 49th ICFA Advanced Beam Dynamics Workshop on Electron Cloud Physics  

DOE Data Explorer (OSTI)

ECLOUD10, the 49h ICFA Advanced Beam Dynamics Workshop took place from October 8 to 12, 2010 at Cornell University, Ithaca, New York, USA. The development of the electron cloud (EC) in accelerator vacuum systems remains a significant issue for the operation of present and planned high intensity accelerators. The interaction of the cloud with the beam can lead to single and multi-bunch instabilities, emittance growth, and betatron tune shifts. The presence of the cloud in the beam chambers can result in a rapid rise in vacuum pressure, significant heat loads on cryogenic surfaces, and can interfere with beam diagnostics. Since the last ECLOUD workshop in 2007, an intense R&D effort has been underway to further understand the physics of the EC and to investigate new methods to mitigate the EC effects. The ECLOUD10 program focused on: a review of EC observations at existing machines; recent experimental efforts to characterize the EC (including EC diagnostics, experimental techniques, characterization of mitigation methods, and characterization of beam instabilities and emittance growth); the status of EC physics models and simulation codes and their comparison to recently acquired experimental data; and, the mitigation requirements and potential performance limitations imposed by the EC on upgraded and future machines. [copied with minor edits from http://www.lepp.cornell.edu/Events/ECLOUD10/] The agenda page makes slides, videos, and posters available to the public.

367

Instrumentation and Beam Dynamics Study of Advanced Electron-Photon Facility in Indiana University  

SciTech Connect

The Advanced eLectron-PHoton fAcility (ALPHA) is a compact electron accelerator under construction and being commissioned at the Indiana University Center for Exploration of Energy and Matter (CEEM). In this thesis, we have studied the refurbished Cooler Injector Synchrotron (CIS) RF cavity using both the transmission line model and SUPERFISH simulation. Both low power and high power RF measurements have been carried out to characterize the cavity. Considering the performance limit of ferrite, we have designed a new ferrite loaded, co-axial quarter wave like cavity with similar structure but a more suitable ferrite material. We have also designed a traveling wave stripline kicker for fast extraction by POISSON and Microwave Studio. The strips geometry is trimmed to maximize the uniformity of the kicking field and match the impedance of the power cables. The time response simulation shows the kicker is fast enough for machine operation. The pulsed power supply requirement has also been specified. For the beam diagnosis in the longitudinal direction, we use a wideband Wall Gap Monitor (WGM) served in CIS. With proper shielding and amplification to get good WGM signal, we have characterized the injected and extracted beam signal in single pass commissioning, and also verified the debunching effect of the ALPHA storage ring. A modulation-demodulation signal processing method is developed to measure the current and longitudinal profile of injected beam. By scanning the dipole strength in the injection line, we have reconstructed the tomography of the longitudinal phase space of the LINAC beam. In the accumulation mode, ALPHA will be operated under a low energy and high current condition, where intra beam scattering (IBS) becomes a dominant effect on the beam emittance. A self consistent simulation, including IBS effect, gas scattering and linear coupling, has been carried out to calculate the emittance of the stored beam.

Luo, Tianhuan; /Indiana U.

2011-08-01T23:59:59.000Z

368

Breaking the Attosecond, Angstrom and TV/M Field Barriers with Ultra-Fast Electron Beams  

Science Conference Proceedings (OSTI)

Recent initiatives at UCLA concerning ultra-short, GeV electron beam generation have been aimed at achieving sub-fs pulses capable of driving X-ray free-electron lasers (FELs) in single-spike mode. This use of very low Q beams may allow existing FEL injectors to produce few-100 attosecond pulses, with very high brightness. Towards this end, recent experiments at the LCLS have produced {approx}2 fs, 20 pC electron pulses. We discuss here extensions of this work, in which we seek to exploit the beam brightness in FELs, in tandem with new developments in cryogenic undulator technology, to create compact accelerator-undulator systems that can lase below 0.15 {angstrom}, or be used to permit 1.5 {angstrom} operation at 4.5 GeV. In addition, we are now developing experiments which use the present LCLS fs pulses to excite plasma wakefields exceeding 1 TV/m, permitting a table-top TeV accelerator for frontier high energy physics applications.

Rosenzweig, James; Andonian, Gerard; Fukasawa, Atsushi; Hemsing, Erik; Marcus, Gabriel; Marinelli, Agostino; Musumeci, Pietro; O'Shea, Brendan; O'Shea, Finn; Pellegrini, Claudio; Schiller, David; Travish, Gil; /UCLA; Bucksbaum, Philip; Hogan, Mark; Krejcik, Patrick; /SLAC; Ferrario, Massimo; /INFN, Rome; Full, Steven; /Penn State U.; Muggli, Patric; /Southern California U.

2012-06-22T23:59:59.000Z

369

Determination of the displacement energy of O, Si and Zr under electron beam irradiation  

Science Conference Proceedings (OSTI)

The response of nanocrystalline, stabilizer-free cubic zirconia thin films on a Si substrate to electron beam irradiation with energies of 4, 110 and 200 keV and fluences up to {approx}1.5 x 10{sup 22} e m{sup -2} has been studied to determine the displacement energies. The 110 and 200 keV irradiations were performed in situ using a transmission electron microscope; the 4 keV irradiations were performed ex situ using an electron gun. In all three irradiations, no structural modification of the zirconia was observed, despite the high fluxes and fluences. However the Si substrate on which the zirconia film was deposited was amorphized under the 200 keV electron irradiation. Examination of the electron-solid interactions reveals that the kinetic energy transfer from the 200 keV electrons to the silicon lattice is sufficient to cause atomic displacements, resulting in amorphization. The kinetic energy transfer from the 200 keV electrons to the oxygen sub-lattice of the zirconia may be sufficient to induce defect production, however, no evidence of defect production was observed. The displacement cross-section value of Zr was found to be {approx}400 times greater than that of O indicating that the O atoms are effectively screened from the electrons by the Zr atoms, and, therefore, the displacement of O is inefficient.

Edmondson, Philip D [ORNL; Weber, William J [ORNL; Namavar, Fereydoon [University of Nebraska Medical Center; Zhang, Yanwen [ORNL

2012-01-01T23:59:59.000Z

370

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

371

Surface science analysis of GaAs photocathodes following sustained electron beam delivery  

DOE Green Energy (OSTI)

Degradation of the photocathode materials employed in photoinjectors represents a challenge for sustained operation of nuclear physics accelerators and high power Free Electron Lasers (FEL). Photocathode quantum efficiency (QE) degradation is due to residual gasses in the electron source vacuum system being ionized and accelerated back to the photocathode. These investigations are a first attempt to characterize the nature of the photocathode degradation, and employ multiple surface and bulk analysis techniques to investigate damage mechanisms including sputtering of the Cs-oxidant surface monolayer, other surface chemistry effects, and ion implantation. Surface and bulk analysis studies were conducted on two GaAs photocathodes, which were removed from the JLab FEL DC photoemission gun after delivering electron beam, and two control samples. The analysis techniques include Helium Ion Microscopy (HIM), Rutherford Backscattering Spectrometry (RBS), Atomic Force Microscopy (AFM) and Secondary Ion Mass Spectrometry (SIMS). In addition, two high-polarization strained superlattice GaAs photocathode samples, one removed from the Continuous Electron Beam Accelerator Facility (CEBAF) photoinjector and one unused, were also analyzed using Transmission Electron Microscopy (TEM) and SIMS. It was found that heat cleaning the FEL GaAs wafer introduces surface roughness, which seems to be reduced by prolonged use. The bulk GaAs samples retained a fairly well organized crystalline structure after delivering beam but shows evidence of Cs depletion on the surface. Within the precision of the SIMS and RBS measurements the data showed no indication of hydrogen implantation or lattice damage from ion back bombardment in the bulk GaAs wafers. In contrast, SIMS and TEM measurements of the strained superlattice photocathode show clear crystal damage in the wafer from ion back bombardment.

Carlos Hernandez-Garcia, Fay Hannon, Marcy Stutzman, V. Shutthanandan, Z. Zhu, M. Nandasri, S. V. Kuchibhatla, S. Thevuthasan, W. P. Hess

2012-06-01T23:59:59.000Z

372

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

E-Print Network (OSTI)

Albuquerque, NM 87185 ion beam pulse can excite large-amplitude whistler waves, thereby producing a complex

Kaganovich, I.D.

2010-01-01T23:59:59.000Z

373

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

374

Anti-hydrogen production with positron beam ion trap  

Science Conference Proceedings (OSTI)

In low-energy antiproton physics, it is advantageous to be able to manipulate anti-particles as freely as normal particles. A robust production and storage system for high-quality positrons and antiprotons would be a substantial advance for the development of anti-matter science. The idea of electron beam ion trap could be applied for storage of anti-particle when the electron beam could be replaced by the positron beam. The bright positron beam would be brought about using synchrotron radiation source with a superconducting wiggler. The new scheme for production of anti-particles is proposed by using new accelerator technologies.

Itahashi, Takahisa [Department of Physics, Graduate School of Science, Osaka University 1-1 Machikaneyama, Toyonaka, Osaka 560-0043 (Japan)

2008-08-08T23:59:59.000Z

375

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

376

Quantum theory of stimulated Cerenkov radiation of transverse electromagnetic waves by a low-density electron beam in a medium  

Science Conference Proceedings (OSTI)

The quantum theory of stimulated Cerenkov radiation of transverse electromagnetic waves by an electron beam in an anisotropic medium is presented. Relativistic quantum nonlinear equations of the Cerenkov beam instability are obtained. In the linear approximation, the quantum dispersion equation is derived and the instability growth increments are determined. The nonlinear problem of the saturation of the quantum Cerenkov beam instability is solved. (cerenkov radiation)

Kuzelev, Mikhail V [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2010-01-31T23:59:59.000Z

377

Beta dependence of electron heating in decaying whistler turbulence: Particle-in-cell simulations  

SciTech Connect

Two-dimensional particle-in-cell simulations have been carried out to study electron beta dependence of decaying whistler turbulence and electron heating in a homogeneous, collisionless magnetized plasma. Initially, applied whistler fluctuations at relatively long wavelengths cascade their energy into shorter wavelengths. This cascade leads to whistler turbulence with anisotropic wavenumber spectra which are broader in directions perpendicular to the background magnetic field than in the parallel direction. Comparing the development of whistler turbulence at different electron beta values, it is found that both the wavenumber spectrum anisotropy and electron heating anisotropy decrease with increasing electron beta. This indicates that higher electron beta reduces the perpendicular energy cascade of whistler turbulence. Fluctuation energy dissipation by electron Landau damping responsible for the electron parallel heating becomes weaker at higher electron beta, which leads to more isotropic heating. It suggests that electron kinetic processes are important in determining the properties of whistler turbulence. This kinetic property is applied to discuss the generation of suprathermal strahl electron distributions in the solar wind.

Saito, S. [National Institute of Information and Communications Technology 4-2-1, Nukui-Kitamachi, Koganei, Tokyo 184-8795 (Japan); Peter Gary, S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

2012-01-15T23:59:59.000Z

378

Electron beam-based sources of ultrashort x-ray pulses.  

Science Conference Proceedings (OSTI)

A review of various methods for generation of ultrashort x-ray pulses using relativistic electron beam from conventional accelerators is presented. Both spontaneous and coherent emission of electrons is considered. The importance of the time-resolved studies of matter at picosecond (ps), femtosecond (fs), and atttosecond (as) time scales using x-rays has been widely recognized including by award of a Nobel Prize in 1999 [Zewa]. Extensive reviews of scientific drivers can be found in [BES1, BES2, BES3, Lawr, Whit]. Several laser-based techniques have been used to generate ultrashort x-ray pulses including laser-driven plasmas [Murn, Alte, Risc, Rose, Zamp], high-order harmonic generation [Schn, Rund, Wang, Arpi], and laser-driven anode sources [Ande]. In addition, ultrafast streak-camera detectors have been applied at synchrotron sources to achieve temporal resolution on the picosecond time scale [Wulf, Lind1]. In this paper, we focus on a different group of techniques that are based on the use of the relativistic electron beam produced in conventional accelerators. In the first part we review several techniques that utilize spontaneous emission of electrons and show how solitary sub-ps x-ray pulses can be obtained at existing storage ring based synchrotron light sources and linacs. In the second part we consider coherent emission of electrons in the free-electron lasers (FELs) and review several techniques for a generation of solitary sub-fs x-ray pulses. Remarkably, the x-ray pulses that can be obtained with the FELs are not only significantly shorter than the ones considered in Part 1, but also carry more photons per pulse by many orders of magnitude.

Zholents, A.; Accelerator Systems Division (APS)

2010-09-30T23:59:59.000Z

379

Modular ultrahigh vacuum-compatible gas-injection system with an adjustable gas flow for focused particle beam-induced deposition  

Science Conference Proceedings (OSTI)

A gas-injection system (GIS) heats up a powdery substance and transports the resulting gas through a capillary into a vacuum chamber. Such a system can be used to guide a (metal)organic precursor gas very close to the focal area of an electron or ion beam, where a permanent deposit is created and adheres to the substrate. This process is known as focused particle beam-induced deposition. The authors present design principles and give construction details of a GIS suitable for ultrahigh vacuum usage. The GIS is composed of several self-contained components which can be customized rather independently. It allows for a continuously adjustable gas-flow rate. The GIS was attached to a standard scanning electron microscope (JEOL 6100) and tested with the tungsten precursor W(CO){sub 6}. The analysis of the deposits by means of atomic force microscopy and energy dispersive x-ray spectroscopy provides clear evidence that excellent gas-flow-rate stability and ensuing growth rate and metal-content reproducibility are experienced.

Klingenberger, D.; Huth, M. [Physikalisches Institut, Goethe University, 60438 Frankfurt am Main (Germany)

2009-09-15T23:59:59.000Z

380

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

Science Conference Proceedings (OSTI)

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

Note: This page contains sample records for the topic "beam particle electron" from the National Library of EnergyBeta (NLEBeta).
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381

ELECTRON COUD DYNAMICS IN HIGH-INTENSITY RINGS.  

SciTech Connect

Electron cloud due to beam-induced multipacting is one of the main concerns for the high intensity. Electrons generated and accumulated inside the beam pipe form an ''electron cloud'' that interacts with the circulating charged particle beam. With sizeable amount of electrons, this interaction can cause beam instability, beam loss and emittance growth. At the same time, the vacuum pressure will rise due to electron desorption. This talk intends to provide an overview of the mechanism and dynamics of the typical electron multipacting in various magnetic fields and mitigation measures with different beams.

WANG, L.; WEI, J.

2005-05-16T23:59:59.000Z

382

Light ion sources and target results on PBFA II (Particle Beam Fusion Accelerator II)  

Science Conference Proceedings (OSTI)

Advances in ion beam theory, diagnostics, and experiments in the past two years have enabled efficient generation of intense proton beams on PBFA II, and focusing of the beam power to 5.4 TW/cm{sup 2} on a 6-mm-diameter target. Target experiments have been started with the intense proton beams, since the range of protons at 4--5 MeV is equivalent to that of lithium at 30 MeV. Three series of experiments have been conducted using planar, conical, and cylindrical targets. These tests have provided information on ion beam power density, uniformity, and energy deposition. In order to increase the power density substantially for target implosion experiments, we are now concentrating on development of high voltage lithium ion beams. 10 refs., 13 figs.

Cook, D.L.; Bailey, J.E.; Bieg, K.W.; Bloomquist, D.D.; Coats, R.S.; Chandler, G.C.; Cuneo, M.E.; Derzon, M.S.; Desjarlais, M.P.; Dreike, P.L.; Dukart, R.J.; Gerber, R.A.; Johnson, D.J.; Leeper, R.J.; Lockner, T.R.; McDaniel, D.H.; Maenchen, J.E.; Matzen, M.K.; Mehlhorn, T.A.; Mix, L.P.; Moats, A.R.; Nelson, W.E.; Pointon, T.D.; Pregenzer, A.L.; Quintenz, J.P.; Renk, T.J.; Rosenthal, S.E.; Ruiz, C.L.; Slutz, S.A.; Stinnett, R

1990-01-01T23:59:59.000Z

383

Pulsed power considerations for electron beam pumped krypton fluoride lasers for inertial confinement fusion applications  

SciTech Connect

The Los Alamos National Laboratory inertial confinement fusion (ICF) program is developing the krypton-fluoride excimer laser for use as an ICF driver. The KrF laser has a number of inherent characteristics that make it a promising driver candidate, such as short wavelength (0.25 {mu}m), broad bandwidth to target (>100 cm{sup {minus}1}), pulse-shaping with high dynamic range, and the potential for high overall efficiency (>5%) and repetitive operation. The large KrF laser amplifiers needed for ICF drivers are electron-beam pumped. A key issue for all laser ICF drivers is cost, and a leading cost component of a KrF laser driver is associated with the pulsed power and electron diode. Therefore, the efficient generation of electron beams is a high priority. The Los Alamos ICF program is investigating pulsed-power and diode designs and technologies to further the development of affordable KrF laser ICF drivers. 12 refs., 8 figs.

Rose, E.A.; McDonald, T.E.; Rosocha, L.A.; Harris, D.B.; Sullivan, J.A. (Los Alamos National Lab., NM (USA)); Smith, I.D. (Pulse Sciences, Inc., San Leandro, CA (USA))

1991-01-01T23:59:59.000Z

384

EBT2 dosimetry of x-rays produced by the electron beam from a Plasma Focus for medical applications  

Science Conference Proceedings (OSTI)

The electron beam emitted from the back of Plasma Focus devices is being studied as a radiation source for intraoperative radiation therapy applications. A Plasma Focus device is being developed to this aim, to be utilized as an x-ray source. The electron beam is driven to impinge on 50 {mu}m brass foil, where conversion x-rays are generated. Measurements with gafchromic film are performed to analyse the attenuation of the x-rays beam and to predict the dose given to the culture cell in radiobiological experiments to follow.

Ceccolini, E.; Mostacci, D.; Sumini, M. [Montecuccolino Nuclear Engineering Laboratory - DIENCA, University of Bologna, via dei Colli 16, I-40136 Bologna (Italy); Rocchi, F. [Montecuccolino Nuclear Engineering Laboratory - DIENCA, University of Bologna, via dei Colli 16, I-40136 Bologna (Italy); UTFISSM-PRONOC, ENEA, via Martiri di Monte Sole 4, I-40129 Bologna (Italy); Tartari, A. [Department of Physics, Ferrara University, via Saragat 1, I-44122 Ferrara (Italy); Mariotti, F. [ENEA, IRP-DOS, via dei Colli 16, I-40136 Bologna (Italy)

2012-09-01T23:59:59.000Z

385

Giant Magnetoresistance In Ni/Cu Multilayers Fabricated By Electron-Beam Evaporation  

Science Conference Proceedings (OSTI)

Electron beam evaporation technique has been used to deposit the multilayers of Ni-Cu, represented by Si[BL{sub t}/[Ni(t{sub FM})/Cu(t{sub NM})]xn] where Si is used as a substrate and BL is buffer layer, n is the number of bilayers, t, t{sub FM} and t{sub NM} are thicknesses of buffer layer, ferromagnetic (Ni) and nonmagnetic (Cu) layers, respectively. We characterize the multilayers using M-H curves, magnetoresistance measurement (at room temperature)

Vikram, V.; Rahman, Md. Rizwanur; Katiyar, Monica [Department of Materials and Metallurgical Engineering Indian Institute of Technology Kanpur, Uttar Pradesh, 208016 (India)

2008-04-24T23:59:59.000Z

386

RF design of X-band RF deflector for femtosecond diagnostics of LCLS electron beam  

Science Conference Proceedings (OSTI)

We designed a successful constant impedance traveling wave X-band rf deflector for electron beam diagnostics at the 14 GeV SLAC Linac Coherent Light Source (LCLS). This is the first practical deflector built with a waveguide coupler. The 1-meter rf deflector produces 24 MeV peak transverse kick when powered with 20 MW of 11.424 GHz rf. The design is based on our experience with high gradient X-band accelerating structures. Several deflectors of this design have been built at SLAC and are currently in use. Here we describe the design and distinguishing features of this device.

Dolgashev, Valery A.; Wang Juwen [SLAC National Accelerator Laboratory, Menlo Park, CA, 94025 (United States)

2012-12-21T23:59:59.000Z

387

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

E-Print Network (OSTI)

Two outbreaks of salmonellosis were linked to the consumption of raw California almonds in 2001 and 2004. Current federal regulations mandate that all almonds grown in California are to be treated with a process that results in a 4-log reduction of Salmonella. Since four out of the five approved technologies to pasteurize almonds rely on the application of heat to control Salmonella, the evaluation of alternative technologies against heat resistant Salmonella Senftenberg was imminent. In this study, almonds that were inoculated with S. Enteritidis PT 30 and S. Senftenberg, were treated with electron beam irradiation (e-beam), blanching and oil roasting. The thermal death time (D-value) for S. Enteritidis PT 30 when treated with e-beam was 0.90 kGy, 15 s when subjected to blanching at 88 degrees C, and 13 s when treated with oil at 127 degrees C. Irradiation and thermal resistance of S. Senftenberg was not significantly different (P > 0.05) from S. Enteritidis PT 30. The commercial application of e-beam as a pathogen intervention was assessed through Monte Carlo simulations (MCS) and experimental measurements. The sensory characteristics of almonds commercially treated by e-beam, blanching and roasting were assessed by a consumer panel. Irradiated and blanched almonds did not differ in consumer overall like (P > 0.05). Bitterness and rancidity attributes of irradiated almonds were between a "dislike slightly" and "dislike moderately", whereas blanched and roasted almonds were between "neither like nor dislike" and "like slightly". Almonds commercially irradiated, blanched and roasted were subjected to an accelerated shelf-life test (ASLT) evaluating percentage free fatty acids, peroxide value, and 2-thiobarbituric acid reactive substances (TBARs). No clear differences between treatments were observed at any given point in time in any of the chemical tests. A gas chromatography-mass-spectrometry-olfactometry (MDGC-MS-O) technology was used to compare full aroma and flavor profiles from raw and e-beam irradiated almonds. Differences in the aroma/odor profile and the taste analysis revealed that the difference between raw and irradiated almonds is extremely subtle. In conclusion, e-beam may be a feasible technology to control Salmonella in almonds if used at low doses, as a part of a series of interventions.

Cuervo Pliego, Mary

2011-12-01T23:59:59.000Z

388

BSA 02-23: Delivering Shielded Electron Beams to a Target in a ...  

The apparatus includes a plasma generator aligned with a beam generator for producing plasma to shield an energized beam.

389

Three-dimensional visualization of forming Hepatitis C virus-like particles by electron-tomography  

Science Conference Proceedings (OSTI)

Hepatitis C virus infects almost 170 million people per year but its assembly pathway, architecture and the structures of its envelope proteins are poorly understood. Using electron tomography of plastic-embedded sections of insect cells, we have visualized the morphogenesis of recombinant Hepatitis C virus-like particles. Our data provide a three-dimensional sketch of viral assembly at the endoplasmic reticulum showing different budding stages and contiguity of buds. This latter phenomenon could play an important role during the assembly of wt-HCV and explain the size-heterogeneity of its particles.

Badia-Martinez, Daniel; Peralta, Bibiana [Structural Biology Unit, CIC bioGUNE, CIBERehd, 48160 Derio (Spain)] [Structural Biology Unit, CIC bioGUNE, CIBERehd, 48160 Derio (Spain); Andres, German; Guerra, Milagros [Electron Microscopy Unit, Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Campus Cantoblanco, 28049 Madrid (Spain)] [Electron Microscopy Unit, Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Campus Cantoblanco, 28049 Madrid (Spain); Gil-Carton, David [Structural Biology Unit, CIC bioGUNE, CIBERehd, 48160 Derio (Spain)] [Structural Biology Unit, CIC bioGUNE, CIBERehd, 48160 Derio (Spain); Abrescia, Nicola G.A., E-mail: nabrescia@cicbiogune.es [Structural Biology Unit, CIC bioGUNE, CIBERehd, 48160 Derio (Spain); IKERBASQUE, Basque Foundation for Science, 48011 Bilbao (Spain)

2012-09-01T23:59:59.000Z

390

Reduction of 1/f noise in graphene after electron-beam irradiation  

Science Conference Proceedings (OSTI)

We investigated experimentally the effect of the electron-beam irradiation on the level of the low-frequency 1/f noise in graphene devices. It was found that 1/f noise in graphene reduces with increasing concentration of defects induced by irradiation. The increased amount of structural disorder in graphene under irradiation was verified with micro-Raman spectroscopy. The bombardment of graphene devices with 20-keV electrons reduced the noise spectral density, S{sub I}/I{sup 2} (I is the source-drain current) by an order-of magnitude at the radiation dose of 10{sup 4} {mu}C/cm{sup 2}. We analyzed the observed noise reduction in the limiting cases of the mobility and carrier number fluctuation mechanisms. The obtained results are important for the proposed graphene applications in analog, mixed-signal, and radio-frequency systems, integrated circuits and sensors.

Zahid Hossain, Md. [Nano-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California-Riverside, Riverside, California 92521 (United States)] [Nano-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California-Riverside, Riverside, California 92521 (United States); Rumyantsev, Sergey [Center for Integrated Electronics and Department of Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States) [Center for Integrated Electronics and Department of Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Ioffe Physical-Technical Institute, The Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); Shur, Michael S. [Center for Integrated Electronics and Department of Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)] [Center for Integrated Electronics and Department of Electrical, Computer, and Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Balandin, Alexander A. [Nano-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California-Riverside, Riverside, California 92521 (United States) [Nano-Device Laboratory, Department of Electrical Engineering, Bourns College of Engineering, University of California-Riverside, Riverside, California 92521 (United States); Materials Science and Engineering Program, University of California-Riverside, Riverside, California 92521 (United States)

2013-04-15T23:59:59.000Z

391

High electron mobility in Ga(In)NAs films grown by molecular beam epitaxy  

Science Conference Proceedings (OSTI)

We report the highest mobility values above 2000 cm{sup 2}/Vs in Si doped GaNAs film grown by molecular beam epitaxy. To understand the feature of the origin which limits the electron mobility in GaNAs, temperature dependences of mobility were measured for high mobility GaNAs and referential low mobility GaInNAs. Temperature dependent mobility for high mobility GaNAs is similar to the GaAs case, while that for low mobility GaInNAs shows large decrease in lower temperature region. The electron mobility of high quality GaNAs can be explained by intrinsic limiting factor of random alloy scattering and extrinsic factor of ionized impurity scattering.

Miyashita, Naoya; Ahsan, Nazmul; Monirul Islam, Muhammad; Okada, Yoshitaka [Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Inagaki, Makoto [Toyota Technological Institute, 2-12-1 Hisakata, Tempaku-ku, Nagoya 468-8511, Aichi (Japan); Yamaguchi, Masafumi [Research Center for Advanced Science and Technology (RCAST), The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Toyota Technological Institute, 2-12-1 Hisakata, Tempaku-ku, Nagoya 468-8511, Aichi (Japan)

2012-11-26T23:59:59.000Z

392

Low-energy electron spectrum of a copper target bombarded by {alpha}-particles of {sup 238}Pu  

Science Conference Proceedings (OSTI)

The ({alpha}e) time coincidence method is applied to study the low-energy electron spectrum of a copper target bombarded by {alpha}-particles of {sup 238}Pu. Ionization of atoms bombarded by charged particles is considered as the shaking of electrons into the continuous spectrum due to a sudden perturbation by a flying particle. A comparison of experimental and calculated distributions showed good agreement, which confirms the accuracy of the ionization description as a result of the shaking effect.

Kupryashkin, V. T., E-mail: kupryashkinvt@yahoo.com; Sidorenko, L. P.; Feoktistov, A. I.; Rovenskykh, E. P. [National Academy of Sciences, Institute for Nuclear Research (Ukraine)

2011-04-15T23:59:59.000Z

393

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

394

Selective atomic layer deposition with electron-beam patterned self-assembled monolayers  

Science Conference Proceedings (OSTI)

The authors selectively deposited nanolines of titanium oxide (TiO{sub 2}) through atomic layer deposition (ALD) using an octadecyltrichlorosilane (OTS) self-assembled monolayer (SAM) as a nucleation inhibition layer. Electron-beam (e-beam) patterning is used to prepare nanoline patterns in the OTS SAM on SiO{sub 2}/Si substrates suitable for selective ALD. The authors have investigated the effect of an e-beam dose on the pattern width of the selectively deposited TiO{sub 2} lines. A high dose (e.g., 20 nC/cm) causes broadening of the linewidth possibly due to scattering, while a low dose (e.g., 5 nC/cm) results in a low TiO{sub 2} deposition rate because of incomplete exposure of the OTS SAMs. The authors have confirmed that sub-30 nm isolated TiO{sub 2} lines can be achieved by selective ALD combined with OTS patterned by EBL at an accelerating voltage of 2 kV and line dose of 10 nC/cm. This research offers a new approach for patterned gate dielectric layer fabrication, as well as potential applications for nanosensors and solar cells.

Huang, Jie; Lee, Mingun; Kim, Jiyoung [Department of Material Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States); Department of Material Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 and Dongjin Semichem Co., Ltd, 625-3, Yodang-ri, Yangam-myun, Hwasung-si, Gyeonggi-do, 445-930 (Korea, Republic of); Department of Material Science and Engineering, University of Texas at Dallas, Richardson, Texas 75080 (United States)

2012-01-15T23:59:59.000Z

395

BOOSTER GOLD BEAM INJECTION EFFICIENCY AND BEAM LOSS  

SciTech Connect

The Relativistic Heavy Ion Collider (RHIC) at the BNL requires the AGS to provide Gold beam with the intensity of 10{sup 9} ions per bunch. Over the years, the Tandem Van de Graaff has provided steadily increasing intensity of gold ion beams to the AGS Booster. However, the gold beam injection efficiency at the Booster has been found to decrease with the rising intensity of injected beams. As the result, for Tandem beams of the highest intensity, the Booster late intensity is lower than with slightly lower intensity Tandem beam. In this article, the authors present two experiments associated with the Booster injection efficiency and beam intensity. One experiment looks at the Booster injection efficiency by adjusting the Tandem beam intensity, and another looks at the beam life time while scraping the beam in the Booster. The studies suggest that the gold beam injection efficiency at the AGS Booster is related to the beam loss in the ring, rather than the intensity of injected beam or circulating beam. A close look at the effect of the lost gold ion at the Booster injection leads to the prediction that the lost gold ion creates large number of positive ions, and even larger number of electrons. The lost gold beam is also expected to create large numbers of neutral particles. In 1998 heavy ion run, the production of positive ions and electrons due to the lost gold beam has been observed. Also the high vacuum pressure due to the beam loss, presumably because of the neutral particles it created, has been measured. These results will be reported elsewhere.

ZHANG,S.Y.; AHRENS,L.A.

1998-06-22T23:59:59.000Z

396

A system of beam energy measurement based on the Compton backscattered laser photons for the VEPP-2000 electron-positron collider  

E-Print Network (OSTI)

The beam energy measurement system for the VEPP-2000 electron-positron collider is described. The method of Compton backscattering of $CO$ laser photons on the electron beam is used. The relative systematic uncertainty of the beam energy determination is estimated as 6\\cdot10^{-5}. It was obtained through comparison of the results of the beam energy measurements using the Compton backscattering and resonance depolarization methods.

E. V. Abakumova; M. N. Achasov; D. E. Berkaev; V. V. Kaminsky; I. A. Koop; A. A. Korol; S. V. Koshuba; A. A. Krasnov; N. Yu. Muchnoi; E. A. Perevedentsev; E. E. Pyata; P. Yu. Shatunov; Yu. M. Shatunov; D. B. Shwartz

2013-10-29T23:59:59.000Z

397

A system of beam energy measurement based on the Compton backscattered laser photons for the VEPP-2000 electron-positron collider  

E-Print Network (OSTI)

The beam energy measurement system for the VEPP-2000 electron-positron collider is described. The method of Compton backscattering of $CO$ laser photons on the electron beam is used. The relative systematic uncertainty of the beam energy determination is estimated as 6\\cdot10^{-5}. It was obtained through comparison of the results of the beam energy measurements using the Compton backscattering and resonance depolarization methods.

Abakumova, E V; Berkaev, D E; Kaminsky, V V; Koop, I A; Korol, A A; Koshuba, S V; Krasnov, A A; Muchnoi, N Yu; Perevedentsev, E A; Pyata, E E; Shatunov, P Yu; Shatunov, Yu M; Shwartz, D B

2013-01-01T23:59:59.000Z

398

ADVANCED METHODS FOR THE COMPUTATION OF PARTICLE BEAM TRANSPORT AND THE COMPUTATION OF ELECTROMAGNETIC FIELDS AND MULTIPARTICLE PHENOMENA  

Science Conference Proceedings (OSTI)

Since 1980, under the grant DEFG02-96ER40949, the Department of Energy has supported the educational and research work of the University of Maryland Dynamical Systems and Accelerator Theory (DSAT) Group. The primary focus of this educational/research group has been on the computation and analysis of charged-particle beam transport using Lie algebraic methods, and on advanced methods for the computation of electromagnetic fields and multiparticle phenomena. This Final Report summarizes the accomplishments of the DSAT Group from its inception in 1980 through its end in 2011.

Alex J. Dragt

2012-08-31T23:59:59.000Z

399

Generating Periodic Terahertz Structures in a Relativistic Electron Beam through Frequency Down-Conversion of Optical Lasers  

SciTech Connect

We report generation of density modulation at terahertz (THz) frequencies in a relativistic electron beam through laser modulation of the beam longitudinal phase space. We show that by modulating the energy distribution of the beam with two lasers, density modulation at the difference frequency of the two lasers can be generated after the beam passes through a chicane. In this experiment, density modulation around 10 THz was generated by down-converting the frequencies of an 800 nm laser and a 1550 nm laser. The central frequency of the density modulation can be tuned by varying the laser wavelengths, beam energy chirp, or momentum compaction of the chicane. This technique can be applied to accelerator-based light sources for generation of coherent THz radiation and marks a significant advance toward tunable narrow-band THz sources.

Dunning, Michael

2012-07-19T23:59:59.000Z

400

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

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

Monte Carlo Simulation of the Conversion X-Rays from the Electron Beam of PFMA-3  

SciTech Connect

PFMA-3, a dense Plasma Focus device, is being optimized as an X-ray generator. X-rays are obtained from the conversion of the electron beam emitted in the backward direction and driven to impinge on a 50 {mu}m brass foil. Monte Carlo simulations of the X-ray emission have been conducted with MCNPX. The electron spectrum had been determined experimentally and is used in the present work as input to the simulations. Dose to the brass foil has been determined both from simulations and from measurements with a thermographic camera, and the two results are found in excellent agreement, thus validating further the electron spectrum assumed as well as the simulation set-up. X-ray emission has been predicted both from bremsstrahlung and from characteristic lines. The spectrum has been found to be comprised of two components of which the one at higher energy, 30 divide 70 keV, is most useful for IORT applications. The results are necessary to estimate penetration in and dose to Standard Human Tissue.

Ceccolini, E.; Mostacci, D.; Sumini, M. [Montecuccolino Nuclear Engineering Laboratory, University of Bologna, via dei Colli 16, I-40136 Bologna (Italy); Rocchi, F. [Montecuccolino Nuclear Engineering Laboratory, University of Bologna, via dei Colli 16, I-40136 Bologna (Italy); UTFISSM-PRONOC, ENEA, via Martiri di Monte Sole 4, I-40129 Bologna (Italy); Tartari, A. [Department of Physics, University of Ferrara, Via Saragat 1, I-44122 Ferrara (Italy)

2011-12-13T23:59:59.000Z

402

Faraday cup with nanosecond response and adjustable impedance for fast electron beam characterization  

Science Conference Proceedings (OSTI)

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

403

Experimental investigations of electron capture from atomic hydrogen and deuterium by alpha particles  

DOE Green Energy (OSTI)

We report progress made during the period 15 September 1991--14 September 1992 on the project Experimental Investigations of Electron Capture from Atomic Hydrogen and Deuterium by Alpha Particles''. In the past year we have developed reliable, narrow energy spread, high-current sources of He[sup ++] based on direct-current magentron and electron-cyclotron resonance discharges. These sources have been proven on our test bench accelerator which has been upgraded to also allow us to test atomic hydrogen effusive targets. We have thus made substantial progress toward our goal of studying single electron capture from atomic hydrogen by doubly-ionized helium. A research plan for the upcoming year is also presented.

Gay, T.J.; Park, J.T.

1992-01-01T23:59:59.000Z

404

Correlation of Beam Electron and LED Signal Losses under Irradiation and Long-term Recovery of Lead Tungstate Crystals  

E-Print Network (OSTI)

Radiation damage in lead tungstate crystals reduces their transparency. The calibration that relates the amount of light detected in such crystals to incident energy of photons or electrons is of paramount importance to maintaining the energy resolution the detection system. We report on tests of lead tungstate crystals, read out by photomultiplier tubes, exposed to irradiation by monoenergetic electron or pion beams. The beam electrons themselves were used to measure the scintillation light output, and a blue light emitting diode (LED) was used to track variations of crystals transparency. We report on the correlation of the LED measurement with radiation damage by the beams and also show that it can accurately monitor the crystals recovery from such damage.

V. A. Batarin; J. Butler; A. M. Davidenko; A. A. Derevschikov; Y. M. Goncharenko; V. N. Grishin; V. A. Kachanov; A. S. Konstantinov; V. I. Kravtsov; Y. Kubota; V. S. Lukanin; Y. A. Matulenko; Y. M. Melnick; A. P. Meschanin; N. E. Mikhalin; N. G. Minaev; V. V. Mochalov; D. A. Morozov; L. V. Nogach; A. V. Ryazantsev; P. A. Semenov; V. K. Semenov; K. E. Shestermanov; L. F. Soloviev; S. Stone; A. V. Uzunian; A. N. Vasiliev; A. E. Yakutin; J. Yarba

2005-04-13T23:59:59.000Z

405

CRADA Final Report for CRADA No. ORNL99-0544, Interfacial Properties of Electron Beam Cured Composites  

SciTech Connect

Electron beam (EB) curing is a technology that promises, in certain applications, to deliver lower cost and higher performance polymer matrix composite (PMC) structures compared to conventional thermal curing processes. PMCs enhance performance by making products lighter, stronger, more durable, and less energy demanding. They are essential in weight- and performance-dominated applications. Affordable PMCs can enhance US economic prosperity and national security. US industry expects rapid implementation of electron beam cured composites in aircraft and aerospace applications as satisfactory properties are demonstrated, and implementation in lower performance applications will likely follow thereafter. In fact, at this time and partly because of discoveries made in this project, field demonstrations are underway that may result in the first fielded applications of electron beam cured composites. Serious obstacles preventing the widespread use of electron beam cured PMCs in many applications are their relatively poor interfacial properties and resin toughness. The composite shear strength and resin toughness of electron beam cured carbon fiber reinforced epoxy composites were about 25% and 50% lower, respectively, than those of thermally cured composites of similar formulations. The essential purpose of this project was to improve the mechanical properties of electron beam cured, carbon fiber reinforced epoxy composites, with a specific focus on composite shear properties for high performance aerospace applications. Many partners, sponsors, and subcontractors participated in this project. There were four government sponsors from three federal agencies, with the US Department of Energy (DOE) being the principal sponsor. The project was executed by Oak Ridge National Laboratory (ORNL), NASA and Department of Defense (DOD) participants, eleven private CRADA partners, and two subcontractors. A list of key project contacts is provided in Appendix A. In order to properly manage the large project team and properly address the various technical tasks, the CRADA team was organized into integrated project teams (IPT's) with each team focused on specific research areas. Early in the project, the end user partners developed ''exit criteria'', recorded in Appendix B, against which the project's success was to be judged. The project team made several important discoveries. A number of fiber coatings or treatments were developed that improved fiber-matrix adhesion by 40% or more, according to microdebond testing. The effects of dose-time and temperature-time profiles during the cure were investigated, and it was determined that fiber-matrix adhesion is relatively insensitive to the irradiation procedure, but can be elevated appreciably by thermal postcuring. Electron beam curable resin properties were improved substantially, with 80% increase in electron beam 798 resin toughness, and {approx}25% and 50% improvement, respectively, in ultimate tensile strength and ultimate tensile strain vs. earlier generation electron beam curable resins. Additionally, a new resin electron beam 800E was developed with generally good properties, and a very notable 120% improvement in transverse composite tensile strength vs. earlier generation electron beam cured carbon fiber reinforced epoxies. Chemical kinetics studies showed that reaction pathways can be affected by the irradiation parameters, although no consequential effects on material properties have been noted to date. Preliminary thermal kinetics models were developed to predict degree of cure vs. irradiation and thermal parameters. These models are continually being refined and validated. Despite the aforementioned impressive accomplishments, the project team did not fully realize the project objectives. The best methods for improving adhesion were combined with the improved electron beam 3K resin to make prepreg and uni-directional test laminates from which composite properties could be determined. Nevertheless, only minor improvements in the composite shear strength, and moderate improvements i

Janke, C.J.

2005-10-17T23:59:59.000Z

406

Versatile 0. 5 TW electron beam facility for power conditioning studies of large rare-gas/halide lasers  

Science Conference Proceedings (OSTI)

Rare-gas/halide lasers which are being developed for Inertial Confinement Fusion will require large area, low impedance electron beam drivers. A wide range of electron beam parameters are being considered for future systems in an effort to optimize the overall system design. A number of power conditioning issues must be investigated in order to obtain a better understanding of the various trade-offs involved in making such optimizations. The RAYITO electron beam accelerator is being designed and built at Sandia National Laboratories and will be used for such investigations. It will be capable of operating in either a 2 or 4 ohm configuration at 1 MV, 50 ns or 0.8 MV, 200 ns. Design details for RAYITO are presented in this paper. Experiments planned for this facility are also discussed.

Ramirez, J. J.

1980-01-01T23:59:59.000Z

407

Electron collisional detachment processes for a 250 keV D/sup -/ ion beam in a partially ionized hydrogen target  

DOE Green Energy (OSTI)

Neutral atom beams with energies above 200 keV may be required for various purposes in magnetic fusion devices following TFTR, JET and MFTF-B. These beams can be produced much more efficiently by electron detachment from negative ion beams than by electron capture by positive ions. We have investigated the efficiency with which such neutral atoms can be produced by electron detachment in partially ionized hydrogen plasma neutralizers.

Savas, S.E.

1980-09-01T23:59:59.000Z

408

Study And Comparison Of Silver Mirrors Deposited On Different Substrates By Electron-Beam Gun Method  

SciTech Connect

Choosing the right substrate is one of the important factors for improving quality parameters of thin films such as adhesion between layers and substrates. The selected substrate should have proper physical and chemical compatibility with deposited thin film. In this paper, we have been investigated four different types of high reflective laser mirrors that were produced in similar conditions on four different kinds of substrates including copper, stainless steel, brass, and nickel. We used electron-beam gun method for deposition of silver layers. At the end we compared theoretical results with practical results that were yielded by laser damage threshold test. It was shown that brass is the best choice for silver metal mirrors as a substrate.

Asl, Jahanbakhsh Mashaiekhy; Shafieizadeh, Zahra; Sabbaghzadeh, Jamshid; Anaraki, Mahdi [Iranian National Center for Laser Science and Technology, PO Box 14665-576, Tehran (Iran, Islamic Republic of)

2010-12-23T23:59:59.000Z

409

New Measurements of the Transverse Beam Asymmetry for Elastic Electron Scattering from Selected Nuclei  

Science Conference Proceedings (OSTI)

We have measured the beam-normal single-spin asymmetry A{sub n} in the elastic scattering of 1-3 GeV transversely polarized electrons from {sup 1}H and for the first time from {sup 4}He, {sup 12}C, and {sup 208}Pb. For {sup 1}H, {sup 4}He and {sup 12}C, the measurements are in agreement with calculations that relate A{sub n} to the imaginary part of the two-photon exchange amplitude including inelastic intermediate states. Surprisingly, the {sup 208}Pb result is significantly smaller than the corresponding prediction using the same formalism. These results suggest that a systematic set of new A{sup n} measurements might emerge as a new and sensitive probe of the structure of heavy nuclei.

Abrahamyan, S; Afanasev, A; Ahmed, Z; Albataineh, H; Aniol, K; Armstrong, D S; Armstrong, W; Arrington, J; Averett, T; Babineau, B; Bailey, S L; Barber, J; Barbieri, A; Beck, A; Bellini, V; Beminiwattha, R; Benaoum, H; Benesch, J; Benmokhtar, F; Bertin, P; Bielarski, T; Boeglin, W; Bosted, P; Butaru, F; Burtin, E; Cahoon, J; Camsonne, A; Canan, M; Carter, P; Chang, C C; Cates, G D; Chao, Y -C; Chen, C; Chen, J -P; Choi, Seonho; Chudakov, E; Cisbani, E; Craver, B; Cusanno, F; Dalton, M M; De Leo, R; de Jager, K; Deconinck, W; Decowski, P; Deepa, D; Deng, X; Dutta, D; Etile, A; Ferdi, C; Feuerbach, J; Finn, J M; Flay, D; Franklin, G B; Friend, M; Frullani, S; Fuchey, E; Fuchs, S A; Fuoti, K; Garibaldi, F; Gasser, E; Gilman, R; Guisa, A; Glamazdin, A; Glesener, L E; Gomez, J; Gorchtein, M; Grames, J; Grimm, K; Gu, C; Hansen, O; Hansknecht, J; Hen, O; Higinbotham, D W; Holmes, R S; Holmstrom, T; Horowitz, C J; Hoskins, J; Huang, J; Humensky, T B; Hyde, C E; Ibrahim, H; Itard, F; Jen, C -M; Jensen, E; Jiang, X; Jin, G; Johnston, S; Katich, J; Kaufman, L J; Kelleher, A; Kliakhandler, K; King, P M; Kolarkar, A; Kowalski, S; Kuchina, E; Kumar, K S; Lagamba, L; Lambert, D; LaViolette, P; Leacock, J; Leckey IV, J; Lee, J H; LeRose, J J; Lhuillier, D; Lindgren, R; Liyanage, N; Lubinsky, N; Mammei, J; Mammoliti, F; Margaziotis, D J; Markowitz, P; Mazouz, M; McCormick, K; McCreary, A; McNulty, D; Meekins, D G; Mercado, L; Meziani, Z -E; Michaels, R W; Mihovilovic, M; Moffit, B; Monaghan, P; Muangma, N; Munoz-Camacho, C; Nanda, S; Nelyubin, V; Neyret, D; Nuruzzaman,; Oh, Y; Otis, K; Palmer, A; Parno, D; Paschke, K D; Phillips, S K; Poelker, M; Pomatsalyuk, R; Posik, M; Potokar, M; Prok, K; Puckett, A.J.R.; Qian, X; Qiang, Y; Quinn, B; Rakhman, A; Reimer, P E; Reitz, B; Riordan, S; Roche, J; Rogan, P; Ron, G; Russo, G; Saenboonruang, K; Saha, A; Sawatzky, B; Shahinyan, A; Silwal, R; Singh, J; Sirca, S; Slifer, K; Snyder, R; Solvignon, P; Souder, P A; Sperduto, M L; Subedi, R; Stutzman, M L; Suleiman, R; Sulkosky, V; Sutera, C M; Tobias, W A; Troth, W; Urciuoli, G M; Ulmer, P; Vacheret, A; Voutier, A; Waidyawansa, B; Wang, D; Wang, K; Wexler, J; Whitbeck, A; Wilson, R; Wojtsekhowski, B; Yan, X; Yao, H; Ye, Y; Ye, Z; Yim, V; Zana, L; Zhan, X; Zhang, J; Zhang, Y; Zheng, X; Ziskin, V

2012-11-01T23:59:59.000Z

410

Breakdown Limits on Gigavolt-per-Meter Electron-Beam-Driven Wakefields in Dielectric Structures  

SciTech Connect

First measurements of the breakdown threshold in a dielectric subjected to GV/m wakefields produced by short (30-330 fs), 28.5 GeV electron bunches have been made. Fused silica tubes of 100 {micro}m inner diameter were exposed to a range of bunch lengths, allowing surface dielectric fields up to 27 GV/m to be generated. The onset of breakdown, detected through light emission from the tube ends, is observed to occur when the peak electric field at the dielectric surface reaches 13.8 {+-} 0.7 GV/m. The correlation of structure damage to beam-induced breakdown is established using an array of postexposure inspection techniques.

Thompson, M.C.; /UCLA /LLNL, Livermore; Badakov, H.; Cook, A.M.; Rosenzweig, J.B.; Tikhoplav, R.; Travish, G.; /UCLA; Blumenfeld, I.; Hogan, M.J.; Ischebeck, R.; Kirby, N.; Siemann, R.; Walz, D.; /SLAC; Muggli, P.; /Southern California U.; Scott, A.; /UC, Santa Barbara; Yoder, R.B.; /Manhattan Coll., Riverdale

2008-06-17T23:59:59.000Z

411

Comparison endpoint study of process plasma and secondary electron beam exciter optical emission spectroscopy  

Science Conference Proceedings (OSTI)

Traditionally process plasmas are often studied and monitored by optical emission spectroscopy. Here, the authors compare experimental measurements from a secondary electron beam excitation and direct process plasma excitation to discuss and illustrate its distinctiveness in the study of process plasmas. They present results that show excitations of etch process effluents in a SF{sub 6} discharge and endpoint detection capabilities in dark plasma process conditions. In SF{sub 6} discharges, a band around 300 nm, not visible in process emission, is observed and it can serve as a good indicator of etch product emission during polysilicon etches. Based on prior work reported in literature the authors believe this band is due to SiF{sub 4} gas phase species.

Stephan Thamban, P. L.; Yun, Stuart; Padron-Wells, Gabriel; Hosch, Jimmy W.; Goeckner, Matthew J. [Department of Mechanical Engineering, University of Texas at Dallas, 800W Campbell Road, Richardson, Texas 75080 (United States); Department of Electrical Engineering, University of Texas at Dallas, 800W Campbell Road, Richardson, Texas 75080 (United States); Verity Instruments, Inc., 2901 Eisenhower Street, Carrollton, Texas 75007 (United States); Department of Mathematical Sciences, University of Texas at Dallas, 800 W Campbell Road, Richardson, Texas 75080 (United States)

2012-11-15T23:59:59.000Z

412

Future directions in particle and nuclear physics at multi-GeV hadron beam facilities  

Science Conference Proceedings (OSTI)

This report contains papers on the following topics in particle and nuclear physics: hadron dynamics; lepton physics; spin physics; hadron and nuclear spectroscopy; hadronic weak interactions; and Eta physics. These papers have been indexed separately elsewhere.

Geesaman, D.F. [Argonne National Lab., IL (United States)] [ed.

1993-11-01T23:59:59.000Z

413

Structure-Processing-Property Relationships at the Fiber-Matrix Interface in Electron-Beam Cured Composite Materials  

Science Conference Proceedings (OSTI)

The objective of this project was to characterize the properties of the resin and the fiber- resin interface in electron beam cured materials by evaluating several structural and processing parameters. The Oak Ridge National Laboratory (ORNL) has recently determined that the interlaminar shear strength properties of electron beam cured composites were 19-28% lower than for autoclave cured composites. Low interlaminar shear strength is widely acknowledged as the key barrier to the successfid acceptance and implementation of electron beam cured composites in industry. In this project we found that simple resin modification and process improvements are unlikely to substantially improve the interlaminar shear strength properties of electron beam cured composites. However, sizings and coatings were shown to improve these properties and there appears to be significant potential for further improvement. In this work we determined that the application of epoxy-based, electron beam compatible sizings or coatings onto surface- treated, unsized carbon fibers improved the composite interlaminar shear strength by as much as 55% compared to composites fabricated from surface-treated, unsized carbon fibers and 11 YO compared to composites made from surface-treated, GP sized carbon fibers. This work has identified many promising pathways for increasing the interlaminar shear strength of electron beam cured composites. As a result of these promising developments we have recently submitted a U.S. Department of Energy-Energy Research (DOE-ER) sponsored Laboratory Technical Research-Cooperative Research and Development Agreement (LTR- CRADA) proposal entitled, "Interracial Properties of Electron Beam Cured Composites", to continue this work. If funded, ORNL will lead a 3-year, $2.6 million effort involving eight industrial partners, NASA-Langley, and the U.S. Air Force. The principal objective of this CRADA is to significantly improve the interracial properties of carbon-fiber-reinforced composites beyond the current state-of-the art electron beam cured composites for use in several DOE, DoD, and industrial applications. In addition, several papers from this Laboratory Director's Research and Development (LDRD) project will be submitted to the Society for the Advancement of Materials and Process Engineering for oral presentations and publications.

Janke, C.J.

1998-11-01T23:59:59.000Z

414

Some Particle Properties  

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

Particle Properties Particle Properties An Article Written Originally for Midlevel Teachers Back A particle, increasing its speed because of some force acting on it, gains energy of motion. An electron (negatively charged) gains one electron volt (eV) of energy in accelerating through a vacuum from the negative end to the positive end of a one-volt battery. The one eV of energy is given up to other particles as the electron crashes into the positive end. A proton (positively charged) traveling from positive to negative pole through the vacuum would also gain one eV of energy and give it up in its collision with particles in the negative end. This proton collision is similar to the proton beam collision with a target at Fermilab, but at Fermilab the proton energy is much greater.

415

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 to select a surrogate suitable for use in electron beam irradiation studies of fruits and to evaluate the effect of sugar content on the kinetics of microbial damage and recovery. A 2.0 MeV Van de Graaff linear accelerator was used to apply irradiation (up to 5.0 kGy), using different configurations, on gelatin-based systems with the addition of sugars. The systems were inoculated with pathogenic and non-pathogenic bacteria strains (surrogates). Initial studies showed that Escherichia coli K-12 MG1655 is a suitable surrogate that represents the damage induced to common fruit pathogens by irradiation. The reduction in bacteria population can be maintained by storing samples at 4�°C. An increase in temperature up to 20�°C was enough for the damaged population to recover in 48 hours. Gelatin-based systems proved to be a simple and inexpensive medium to evaluate the effects of irradiation (up to 5.0 kGy) on selected bacteria. Reduction of the system dimensions and their positioning related to the beam source were key factors in increasing the killing effectiveness of irradiation. The sugar levels (up to 8 %) used to mimic the maturity of cantaloupes had no effect on the radiation D10 values and the recovery of the surrogate population quantified as Generation Times. The resistance of the surrogate to irradiation was validated in an optimum configuration and in cantaloupes. Temperature and sugar content caused significantly higher changes to the physical structure of the gel-based systems than irradiation (1.0 kGy). Plate counts and light microscopy techniques demonstrated that the structure of the gelatin-based systems allow for motility of the bacteria in a 3-D array (length, width and depth). When little information was available about the effectiveness of using a low energy linear accelerator, the inoculation of gelatin-based systems proved to be a reliable method to select a suitable surrogate and to predict the effects of irradiation on bacteria as a function of sugar content.

Rodriguez Gonzalez, Oscar

2005-08-01T23:59:59.000Z

416

Laser-induced implantation of silver particles into poly(vinyl alcohol) films and its application to electronic-circuit fabrication on encapsulated organic electronics  

Science Conference Proceedings (OSTI)

In this study, we propose a new laser-induced implantation based approach for embedding electronic interconnects in this study. Direct implantations of silver particles, vaporized by a pulsed laser from a silver film initially pre-coated on a transparent ... Keywords: Embedded electronic circuits, Encapsulation, Laser-induced implantation, Organic thin-film transistors, Polymeric light-emitting diodes

Kun-Tso Chen; Yu-Hsuan Lin; Jeng-Rong Ho; J.-W. John Cheng; Sung-Ho Liu; Jin-Long Liao; Jing-Yi Yan

2010-04-01T23:59:59.000Z

417

Electron Beam-induced Light Emission and Transport in GaN Nanowires  

SciTech Connect

We report observations of electron beam-induced light from GaN nanowires grown by chemical vapor deposition. GaN nanowires were modified in-situ with deposited opaque platinum coatings to estimate the extent to which light is channeled to the ends of nanowires. Some evidence of light channeling was found, but wire microstructure and defects play an important role in light scattering and transport, limiting the extent to which light is confined. Optical interconnects are powerful components presently applied for high bandwidth communications among high-performance processors. Future circuits based on nanometer-scale components could similarly benefit from optical information transfer among processing blocks. Strong light channeling (and even lasing) has been observed in GaN nanowires, suggesting that these structures could be useful building blocks in a future networked electro-optical processor. However, the extent to which defects and microstructure control optical performance in nanowire waveguides has not been measured. In this study, we use electron microscopy and in-situ modification of individual nanowires to begin to correlate wire structure with light transport efficiency through GaN nanowires tens of microns long.

Tringe, J W; MoberlyChan, W J; Stevens, C G; Davydov, A V; Motayed, A

2006-05-10T23:59:59.000Z

418

Transverse envelope dynamics of a 28.5 GeV electron beam in a long plasma  

SciTech Connect

The transverse dynamics of a 28.5 GeV electron beam propagating in a 1.4 m long, 0-2 x 10{sup 14} cm{sup -3} plasma are studied experimentally in the underdense or blow-out regime. The transverse component of the wake field excited by the short electron bunch focuses the bunch, which experiences multiple betatron oscillations as the plasma density is increased. The spot size variations are observed using optical transition radiation and Cherenkov radiation. In this regime, the behavior of the spot size as a function of the plasma density is well described by a simple beam envelope model. Dynamic changes of the beam envelope are observed by time resolving the Cherenkov light.

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

2002-04-01T23:59:59.000Z

419

Manipulating electron beam cancer therapy so it can be used treat internal cancers and tumors has the potential to  

E-Print Network (OSTI)

exposure provides several new cancer therapies or treatments in previously inoperable or radiationManipulating electron beam cancer therapy so it can be used treat internal cancers and tumors has-effective means of treating cancer in previously inoperable or radiation-sensitive areas of the body. Technology

Kemner, Ken

420

NONRELATIVISTIC COLLISIONLESS SHOCKS IN WEAKLY MAGNETIZED ELECTRON-ION PLASMAS: TWO-DIMENSIONAL PARTICLE-IN-CELL SIMULATION OF PERPENDICULAR SHOCK  

Science Conference Proceedings (OSTI)

A two-dimensional particle-in-cell simulation is performed to investigate weakly magnetized perpendicular shocks with a magnetization parameter of {sigma} = 6 x 10{sup -5}, which is equivalent to a high Alfven Mach number M{sub A} of {approx}130. It is shown that current filaments form in the foot region of the shock due to the ion-beam-Weibel instability (or the ion filamentation instability) and that they generate a strong magnetic field there. In the downstream region, these current filaments also generate a tangled magnetic field that is typically 15 times stronger than the upstream magnetic field. The thermal energies of electrons and ions in the downstream region are not in equipartition and their temperature ratio is T{sub e}/T{sub i} {approx} 0.3-0.4. Efficient electron acceleration was not observed in our simulation, although a fraction of the ions are accelerated slightly on reflection at the shock. The simulation results agree very well with the Rankine-Hugoniot relations. It is also shown that electrons and ions are heated in the foot region by the Buneman instability (for electrons) and the ion-acoustic instability (for both electrons and ions). However, the growth rate of the Buneman instability is significantly reduced due to the relatively high temperature of the reflected ions. For the same reason, ion-ion streaming instability does not grow in the foot region.

Kato, Tsunehiko N.; Takabe, Hideaki, E-mail: kato-t@ile.osaka-u.ac.j [Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka 565-0871 (Japan)

2010-09-20T23:59:59.000Z

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421

A hybrid model for particle transport and electron energy distributions in positive column electrical discharges using equivalent species transport  

E-Print Network (OSTI)

A hybrid model for particle transport and electron energy distributions in positive column the fluid portion of the model. Transport coefficients, source functions, and energy distributions for all field has motivated a num- ber of investigations into its effect on the `electron energy distribution

Kushner, Mark

422

Traverse Focusing of Intense Charged Particle Beams with Chromatic Effects for Heavy Ion Fusion  

SciTech Connect

A fi nal focusing scheme designed to minimize chromatic effects is discussed. The Neutralized Drift Compression Experiment-II (NDCX-II) will apply a velocity tilt for longitudinal bunch compression, and a fi nal focusing solenoid (FFS) for transverse bunch compression. In the beam frame, neutralized drift compression causes a suffi#14;ciently large spread in axial momentum, pz , resulting in chromatic effects to the fi nal focal spot during transverse bunch compression. Placing a weaker solenoid upstream of a stronger fi nal focusing solenoid (FFS) mitigates chromatic effects and improves transverse focusing by a factor of approximately 2-4 for appropriate NDCX-II parameters.

James M. Mitrani, Igor D. Kaganovich, Ronald C. Davidson

2013-01-28T23:59:59.000Z

423

Modified theory of secondary electron emission from spherical particles and its effect on dust charging in complex plasma  

SciTech Connect

The authors have modified Chow's theory of secondary electron emission (SEE) to take account of the fact that the path length of a primary electron in a spherical particle varies between zero to the diameter or x{sub m} the penetration depth depending on the distance of the path from the centre of the particle. Further by including this modified expression for SEE efficiency, the charging kinetics of spherical grains in a Maxwellian plasma has been developed; it is based on charge balance over dust particles and number balance of electrons and ionic species. It is seen that this effect is more pronounced for smaller particles and higher plasma temperatures. Desirable experimental work has also been discussed.

Misra, Shikha [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi-110016 (India); Mishra, S. K. [Institute for Plasma Research, Gandhinagar-382428 (India); Sodha, M. S. [Department of Education Building, University of Lucknow, Lucknow-226007 (India)

2013-01-15T23:59:59.000Z

424

Directed flow of Identified Charged Particles from the RHIC Beam Energy Scan  

E-Print Network (OSTI)

We present the STAR measurements of directed flow, v1, for {\\pi}{\\pm}, K{\\pm}, protons and antiprotons, as well as for all detected charged particles in Au + Au collisions at {\\surd}sNN = 7.7, 11.5 and 39 GeV as a function of transverse momentum, rapidity and centrality. Results are compared to the predictions from transport models.

Yadav Pandit; for the STAR Collaboration

2011-12-05T23:59:59.000Z

425

Single-Particle Dynamics in Electron Storage Rings with Extremely Low Emittance  

Science Conference Proceedings (OSTI)

Electron storage rings are widely used for high luminosity colliders, damping rings in high-energy linear colliders, and synchrotron light sources. They have become essential facilities to study high-energy physics and material and medical sciences. To further increase the luminosity of colliders or the brightness of synchrotron light sources, the beam emittance is being continually pushed downward, recently to the nanometer region. In the next decade, another order of reduction is expected. This requirement of ultra-low emittance presents many design challenges in beam dynamics, including better analysis of maps and improvement of dynamic apertures. To meet these challenges, we have refined transfer maps of common elements in storage rings and developed a new method to compute the resonance driving terms as they are built up along a beamline. The method is successfully applied to a design of PEP-X as a future light source with 100-pm emittance. As a result, we discovered many unexpected cancelations of the fourth-order resonance terms driven by sextupoles within an achromat.

Cai, Yunhai; /SLAC

2011-05-31T23:59:59.000Z

426

Electron-beam induced electric-hydraulic expansion in a silica-shelled gallium microball-nanotube structure  

Science Conference Proceedings (OSTI)

Heteroshape-heteroscale structure of silica-shelled Ga microball-nanotube was fabricated. Under in situ electron-beam irradiation, an abnormally large and fast expansion of Ga was observed. Failed by a sole routine heating effect of electron-beam, the expansion was explained by an electric-hydraulic expansion effect taking into account a huge inner pressure induced by the repelling Coulomb force of positively charged Ga ions on the Ga microball surface. The ions were accumulated due to knocking-out of Ga electrons under irradiation and shielding effect of a silica shell which prevents the charge balance restoration. A circuit model is proposed to calculate the accumulation of Ga ions.

Gao, Y. H.; Sun, M.; Su, J. [Wuhan National Laboratory for Optoelectronics (WNLO), School of Physics, College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology (HUST), LuoyuRoad 1037, Wuhan 430074 (China); Zhi, C. Y.; Golberg, D.; Bando, Y. [International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba, Ibaraki 305-0044 (Japan); Duan, X. F. [Institute of Physics, Beijing National Laboratory of Condensed Matter Physics, Chinese Academy of Sciences, Beijing 100190 (China)

2011-08-22T23:59:59.000Z

427

X-ray and pressure conditions on the first wall of a particle beam inertial confinement reactor  

SciTech Connect

Because of the presence of a chamber gas in a particle beam reactor cavity, nonneutron target debris created from thermonuclear burn will be modified or stopped before it reaches the first reactor wall. The resulting modified spectra and pulse lengths of the debris need to be calculated to determine first wall effects. Further, the cavity overpressure created by the momentum and energy exchange between the debris and gas must also be calculated to determine its effect. The purpose of this paper is to present results of the debris-background gas problem obtained with a one fluid, two temperature plasma hydrodynamic computer code model which includes multifrequency radiation transport. Spherical symmetry, ideal gas equation of state, and LTE for each radiation frequency group were assumed. The transport of debris ions was not included and all the debris energy was assumed to be in radiation. The calculated x-ray spectra and pulse lengths and the background overpressure are presented.

Magelssen, G.R.

1979-01-01T23:59:59.000Z

428

Tuning the beam: a physics perspective on beam diagnostic instrumentation  

SciTech Connect

In a nutshell, the role of a beam diagnostic measurement is to provide information needed to get a particle beam from Point A (injection point) to Point B (a target) in a useable condition, with 'useable' meaning the right energy and size and with acceptable losses. Specifications and performance requirements of diagnostics are based on the physics of the particle beam to be measured, with typical customers of beam parameter measurements being the accelerator operators and accelerator physicists. This tutorial will be a physics-oriented discussion of the interplay between tuning evolutions and the beam diagnostics systems that support the machine tune. This will include the differences between developing a tune and maintaining a