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1

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

2

Ultrafast Diagnostics for Electron Beams from Laser Plasma Accelerators  

E-Print Network (OSTI)

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

Matlis, N. H.

2011-01-01T23:59:59.000Z

3

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

4

Improving electron beam quality of the Boeing free electron laser  

Science Journals Connector (OSTI)

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

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

1991-01-01T23:59:59.000Z

5

T-3 electron-beam-excited laser system  

SciTech Connect

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

Klein, R A

1981-02-01T23:59:59.000Z

6

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.

7

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.

8

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.

9

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.

10

Tailored Terahertz Pulses from a Laser-Modulated Electron Beam  

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

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

11

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

12

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

13

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.

14

UNDULATOR-BASED LASER WAKEFIELD ACCELERATOR ELECTRON BEAM DIAGNOSTIC  

SciTech Connect

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

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

2009-05-04T23:59:59.000Z

15

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

E-Print Network (OSTI)

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

Umstadter, Donald

16

Large area electron beam pumped krypton fluoride laser amplifier  

SciTech Connect

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

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

1997-06-01T23:59:59.000Z

17

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

E-Print Network (OSTI)

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

Rocca, Jorge J.

18

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

E-Print Network (OSTI)

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

Umstadter, Donald

19

Characterisation of electron beams from laser-driven particle accelerators  

SciTech Connect

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

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

2012-12-21T23:59:59.000Z

20

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

E-Print Network (OSTI)

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

Feng, Chao; Deng, Haixiao; Zhao, Zhentang

2014-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

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

E-Print Network (OSTI)

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

Umstadter, Donald

22

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

E-Print Network (OSTI)

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

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

2014-01-01T23:59:59.000Z

23

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

E-Print Network (OSTI)

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

24

Spectral evolution in an electron beam pumped XeF laser  

SciTech Connect

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

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

1987-10-19T23:59:59.000Z

25

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

E-Print Network (OSTI)

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

Umstadter, Donald

26

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

E-Print Network (OSTI)

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

Seipt, D; Fritzsche, S

2014-01-01T23:59:59.000Z

27

Electron-beamdeposited distributed polarization rotator for high-power laser applications  

Science Journals Connector (OSTI)

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

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

2014-01-01T23:59:59.000Z

28

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

29

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

SciTech Connect

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

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

2009-04-24T23:59:59.000Z

30

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

SciTech Connect

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

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

2004-11-01T23:59:59.000Z

31

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

SciTech Connect

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

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

2009-04-15T23:59:59.000Z

32

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

E-Print Network (OSTI)

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

N. B. Skachkov

2005-03-01T23:59:59.000Z

33

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

E-Print Network (OSTI)

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

S. Son; S. J. Moon

2012-02-12T23:59:59.000Z

34

Testing General Relativity With Laser Accelerated Electron Beams  

E-Print Network (OSTI)

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

L. . Gergely; T. Harko

2012-07-16T23:59:59.000Z

35

Testing general relativity with laser accelerated electron beams  

SciTech Connect

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

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

2012-07-09T23:59:59.000Z

36

Demonstration of electron beam focusing by a laser-plasma lens  

E-Print Network (OSTI)

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

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

2014-01-01T23:59:59.000Z

37

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

SciTech Connect

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

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

1990-11-01T23:59:59.000Z

38

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

SciTech Connect

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

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

2012-07-23T23:59:59.000Z

39

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

Science Journals Connector (OSTI)

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

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

1990-01-01T23:59:59.000Z

40

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

E-Print Network (OSTI)

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

Scott, R H H

2015-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

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

E-Print Network (OSTI)

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

Geng, Rong-Li

42

A PLASMA CHANNEL BEAM CONDITIONER FOR A FREE ELECTRON LASER  

E-Print Network (OSTI)

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

Wurtele, Jonathan

43

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

SciTech Connect

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

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

2014-04-15T23:59:59.000Z

44

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

DOE Patents (OSTI)

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

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

1986-01-01T23:59:59.000Z

45

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

E-Print Network (OSTI)

We report on a quantitative measurement of the spatial coherence of electrons emitted from a sharp metal needle tip. We investigate the coherence in photoemission using near-ultraviolet laser triggering with a photon energy of 3.1 eV and compare it to DC-field emission. A carbon-nanotube is brought in close proximity to the emitter tip to act as an electrostatic biprism. From the resulting electron matter wave interference fringes we deduce an upper limit of the effective source radius both in laser-triggered and DC-field emission mode, which quantifies the spatial coherence of the emitted electron beam. We obtain $(0.80\\pm 0.05)\\,$nm in laser-triggered and $(0.55\\pm 0.02)\\,$nm in DC-field emission mode, revealing that the outstanding coherence properties of electron beams from needle tip field emitters are largely maintained in laser-induced emission. In addition, the relative coherence width of 0.36 of the photoemitted electron beam is the largest observed so far. The preservation of electronic coherence du...

Ehberger, Dominik; Eisele, Max; Krger, Michael; Noe, Jonathan; Hgele, Alexander; Hommelhoff, Peter

2014-01-01T23:59:59.000Z

46

Electron Beam Charge Diagnostics for Laser Plasma Accelerators  

E-Print Network (OSTI)

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

Nakamura, Kei

2012-01-01T23:59:59.000Z

47

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

E-Print Network (OSTI)

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

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

2014-01-01T23:59:59.000Z

48

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

SciTech Connect

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

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

1987-06-01T23:59:59.000Z

49

Observations of the filamentation of high-intensity laser-produced electron beams M. S. Wei,1  

E-Print Network (OSTI)

be necessary for actual ignition experiments, the required laser needs to have energies of tens of kObservations of the filamentation of high-intensity laser-produced electron beams M. S. Wei,1 F. N Central Laser Facility, Rutherford Appleton Laboratory, Chilton, Oxon OX11 OQX, United Kingdom 5

Strathclyde, University of

50

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

SciTech Connect

A new concept of Heavy Ion Beam Probe (HIBP) diagnostic has been proposed, of which the key is to replace the electrostatic accelerator of traditional HIBP by a laser-driven ion accelerator. Due to the large energy spread of ions, the laser-accelerated HIBP can measure the two-dimensional (2D) electron density profile of tokamak plasma. In a preliminary simulation, a 2D density profile was reconstructed with a spatial resolution of about 2 cm, and with the error below 15% in the core region. Diagnostics of 2D density fluctuation is also discussed.

Chen, Y. H.; Yang, X. Y.; Lin, C., E-mail: linchen0812@pku.edu.cn, E-mail: cjxiao@pku.edu.cn; Wang, X. G.; Xiao, C. J., E-mail: linchen0812@pku.edu.cn, E-mail: cjxiao@pku.edu.cn [State Key Lab of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Wang, L. [Institute of Physics, Chinese Academy of Sciences, P. O. Box 603, Beijing 100190 (China); Xu, M. [Center for Fusion Science of Southwestern Institute of Physics, P. O. Box 432, Chengdu 610041 (China)

2014-11-15T23:59:59.000Z

51

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

SciTech Connect

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

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

2014-01-06T23:59:59.000Z

52

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

E-Print Network (OSTI)

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

Osterhoff, Jens

2012-01-01T23:59:59.000Z

53

High-brightness electron beam evolution following laser-based cleaning of a photocathode  

Laser-based techniques have been widely used for cleaning metal photocathodes to increase quantum efficiency (QE). However, the impact of laser cleaning on cathode uniformity and thereby on electron beam quality are less understood. We are evaluating whether this technique can be applied to revive photocathodes used for high-brightness electron sources in advanced x-ray free-electron laser (FEL) facilities, such as the Linac Coherent Light Source (LCLS) at the SLAC National Accelerator Laboratory. The laser-based cleaning was applied to two separate areas of the current LCLS photocathode on July 4 and July 26, 2011, respectively. The QE was increased by 810 times upon the laser cleaning. Since the cleaning, routine operation has exhibited a slow evolution of the QE improvement and comparatively rapid improvement of transverse emittance, with a factor of 3 QE enhancement over five months, and a significant emittance improvement over the initial 23 weeks following the cleaning. Currently, the QE of the LCLS photocathode is holding constant at about 1.210?4 , with a normalized injector emittance of about 0.3???m for a 150-pC bunch charge. With the proper procedures, the laser-cleaning technique appears to be a viable tool to revive the LCLS photocathode. We present observations and analyses for the QE and emittance evolution in time following the laser-based cleaning of the LCLS photocathode, and comparison to the previous studies, the measured thermal emittance versus the QE and comparison to the theoretical model.

Zhou, F.; Brachmann, A.; Decker, F-J.; Emma, P.; Gilevich, S.; Iverson, R.; Stefan, P.; Turner, J.

2012-09-01T23:59:59.000Z

54

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

SciTech Connect

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

Guimei Wang

2011-12-31T23:59:59.000Z

55

Circular free-electron laser  

DOE Patents (OSTI)

A high efficiency, free electron laser utilizing a circular relativistic electron beam accelerator and a circular whispering mode optical waveguide for guiding optical energy in a circular path in the circular relativistic electron beam accelerator such that the circular relativistic electron beam and the optical energy are spatially contiguous in a resonant condition for free electron laser operation. Both a betatron and synchrotron are disclosed for use in the present invention. A free electron laser wiggler is disposed around the circular relativistic electron beam accelerator for generating a periodic magnetic field to transform energy from the circular relativistic electron beam to optical energy.

Brau, Charles A. (Los Alamos, NM); Kurnit, Norman A. (Santa Fe, NM); Cooper, Richard K. (Los Alamos, NM)

1984-01-01T23:59:59.000Z

56

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

SciTech Connect

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

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

2012-02-15T23:59:59.000Z

57

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

SciTech Connect

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

Kondo K.; Yamamoto, T.; Sekine, M.; Okamura, M.

2012-02-22T23:59:59.000Z

58

Efficient XeF(C. -->. A) laser oscillation using electron-beam excitation  

SciTech Connect

Significantly improved XeF(C..-->..A) laser energy density and efficiency have been obtained using electron-beam excited Ar-Xe gas mixtures at pressures up to 10 atm which contain both NF/sub 3/ and F/sub 2/. Maximum blue-green laser pulse energy density in excess of 1.0 J/liter was obtained, corresponding to an intrinsic electrical-optical energy conversion efficiency estimated to be in the 0.5%--1.0% range. Comprehensive, time-resolved absolute measurements of XeF(C..-->..A) fluorescence, laser energy, and gain were carried out for a wide variety of experimental conditions. Analysis of these data has resulted in identification of the dominant transient absorbing species in the laser medium. For the laser mixtures investigated in this work, the primary blue/green absorption processes have been identified as photoionization of the 4p, 3d, and higher lying states of Ar, and of the Xe 6p and 5d states, and photodissociation of Ar/sub 2/(/sup 3/summation/sup +//sub u/) and Ar/sup +//sub 3/.

Nachshon, Y.; Tittel, F.K.; Wilson, W.L. Jr.; Nighan, W.L.

1984-07-01T23:59:59.000Z

59

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

SciTech Connect

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

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

2011-03-01T23:59:59.000Z

60

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

SciTech Connect

A novel thermionic electron gun adopted for use in a high power THz free electron laser (FEL) is proposed in this paper. By optimization of the structural and radiofrequency (RF) parameters, the physical design of the gun is performed using dynamic calculations. Velocity bunching is used to minimize the bunch's energy spread, and the dynamic calculation results indicate that high quality beams can be provided. The transverse properties of the beams generated by the gun are also analyzed. The novel RF focusing effects of the resonance cavity are investigated precisely and are used to establish emittance compensation, which enables the injector length to be reduced. In addition, the causes of the extrema of the beam radius and the normalized transverse emittance are analyzed and interpreted, respectively, and slice simulations are performed to illustrate how the RF focusing varies along the bunch length and to determine the effects of that variation on the emittance compensation. Finally, by observation of the variations of the beam properties in the drift tube behind the electron gun, prospective assembly scenarios for the complete THz-FEL injector are discussed, and a joint-debugging process for the injector is implemented.

Hu, Tongning, E-mail: TongningHu@hust.edu.cn, E-mail: yjpei@ustc.edu.cn; Qin, Bin; Tan, Ping; Chen, Qushan; Yang, Lei [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Pei, Yuanji, E-mail: TongningHu@hust.edu.cn, E-mail: yjpei@ustc.edu.cn; Li, Ji [National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China)

2014-10-15T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

Potential For Laser-Induced Microbunching Studies with the 3-MHZ-Rate Electron Beams at ASTA  

E-Print Network (OSTI)

Investigations of the laser-induced microbunching as it is related to time-sliced electron-beam diagnostics and high-gain-harmonic generation (HGHG) free-electron lasers using bright electron beams are proposed for the ASTA facility. Initial tests at 40-50 MeV with an amplified 800-nm seed laser beam co-propagating with the electron beam through a short undulator (or modulator) tuned for the resonance condition followed by transport through a subsequent chicane will result in energy modulation and z-density modulation (microbunching), respectively. The latter microbunching will result in generation of coherent optical or UV transition radiation (COTR, CUVTR) at a metal converter screen which can reveal slice beam size, centroid, and energy spread. Additionally, direct assessment of the microbunching factors related to HGHG by measurement of the COTR intensity and harmonic content after the chicane as a function of seed laser power and beam parameters will be done. These experiments will be performed using the...

Lumpkin, A H; Byrd, J M; Wilcox, R B

2014-01-01T23:59:59.000Z

62

Laser Telecommunication timeLaser beam  

E-Print Network (OSTI)

Laser Telecommunication Experiment Laser time Laser beam intensity timeLaser beam Laser battery Laser connected to a circuit without a modulator. Bottom graph illustrates what happen when a modulating signal is superimposed to the DC voltage driving the laser Laser beam intensity DC Input voltage DC

La Rosa, Andres H.

63

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

E-Print Network (OSTI)

The beam energy spread at the entrance of undulator system is of paramount importance for efficient density modulation in high-gain seeded free-electron lasers (FELs). In this paper, the dependences of high harmonic micro-bunching in the high-gain harmonic generation (HGHG), echo-enabled harmonic generation (EEHG) and phase-merging enhanced harmonic generation (PEHG) schemes on the electron energy spread distribution are studied. Theoretical investigations and multi-dimensional numerical simulations are applied to the cases of uniform and saddle beam energy distributions and compared to a traditional Gaussian distribution. It shows that the uniform and saddle electron energy distributions significantly enhance the performance of HGHG-FELs, while they almost have no influence on EEHG and PEHG schemes. A numerical example demonstrates that, with about 84keV RMS uniform and/or saddle slice energy spread, the 30th harmonic radiation can be directly generated by a single-stage seeding scheme for a soft x-ray FEL f...

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

2015-01-01T23:59:59.000Z

64

Relativistic nonlinear dynamics of an intense laser beam propagating in a hot electron-positron magnetoactive plasma  

SciTech Connect

The present study is devoted to investigation of the nonlinear dynamics of an intense laser beam interacting with a hot magnetized electron-positron plasma. Propagation of the intense circularly polarized laser beam along an external magnetic field is studied using a relativistic two-fluid model. A modified nonlinear Schrdinger equation is derived based on the quasi-neutral approximation, which is valid for hot plasma. Light envelope solitary waves and modulation instability are studied, for one-dimensional case. Using a three-dimensional model, spatial-temporal development of laser pulse is investigated. Occurrence of some nonlinear phenomena such as self-focusing, self-modulation, light trapping, and filamentation of laser pulse is discussed. Also the effect of external magnetic field and plasma temperature on the nonlinear evolution of these phenomena is studied.

Sepehri Javan, N.; Adli, F. [Department of Physics, Faculty of Sciences, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil 56199-11367 (Iran, Islamic Republic of)] [Department of Physics, Faculty of Sciences, University of Mohaghegh Ardabili, P.O. Box 179, Ardabil 56199-11367 (Iran, Islamic Republic of)

2013-06-15T23:59:59.000Z

65

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

SciTech Connect

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

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

2012-12-21T23:59:59.000Z

66

Rf Feedback free electron laser  

DOE Patents (OSTI)

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

Brau, Charles A. (Los Alamos, NM); Swenson, Donald A. (Los Alamos, NM); Boyd, Jr., Thomas J. (Los Alamos, NM)

1981-01-01T23:59:59.000Z

67

Microwave accelerator E-beam pumped laser  

DOE Patents (OSTI)

A device and method for pumping gaseous lasers by means of a microwave accelerator. The microwave accelerator produces a relativistic electron beam which is applied along the longitudinal axis of the laser through an electron beam window. The incident points of the electron beam on the electron beam window are varied by deflection coils to enhance the cooling characteristics of the foil. A thyratron is used to reliably modulate the microwave accelerator to produce electron beam pulses which excite the laser medium to produce laser pulse repetition frequencies not previously obtainable. An aerodynamic window is also disclosed which eliminates foil heating problems, as well as a magnetic bottle for reducing laser cavity length and pressures while maintaining efficient energy deposition.

Brau, Charles A. (Los Alamos, NM); Stein, William E. (Los Alamos, NM); Rockwood, Stephen D. (Los Alamos, NM)

1980-01-01T23:59:59.000Z

68

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

SciTech Connect

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

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

2013-04-22T23:59:59.000Z

69

Free-Electron Laser Targets Fat | Jefferson Lab  

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

Free-Electron Laser Targets Fat April 10, 2006 Free-Electron Laser Scientists Rox Anderson, right, and Free-Electron Laser Scientist Steve Benson, left, discuss laser beam...

70

Single element laser beam shaper  

DOE Patents (OSTI)

A single lens laser beam shaper for converting laser beams from any spatial profile to a flat-top or uniform spatial profile. The laser beam shaper includes a lens having two aspheric surfaces. The beam shaper significantly simplifies the overall structure in comparison with conventional 2-element systems and therefore provides great ease in alignment and reduction of cost.

Zhang, Shukui (Yorktown, VA); Michelle D. Shinn (Newport News, VA)

2005-09-13T23:59:59.000Z

71

Study of the Feasibility of an X-Ray Free Electron Laser with a 15 GeV CLIC Beam  

E-Print Network (OSTI)

This note presents a study of the feasibility of a Free Electron Laser (FEL) using an electron beam from the Compact Linear Collider (CLIC). We first show that, with the nominal CLIC layout, the energy spread at 15 GeV would be too large to allow FEL saturation in an undulator of reasonable length. An alternative scheme was studied, with a dedicated source, with a by-pass of the damping rings and with magnetic compression between the various acceleration stages. With this scheme, the energy spread of the CLIC beam can be reduced from 1.5% to 0.1%, but the emittance is much larger and, although the power gain is better than in the nominal case, FEL saturation is still not reached. We show that the energy spread or the transverse emittance would have to be reduced by another order of magnitude in order to obtain FEL saturation.

Brandin, M; Ekelf, T J C; Ferrari, A

2002-01-01T23:59:59.000Z

72

Combination free electron and gaseous laser  

DOE Patents (OSTI)

A multiple laser having one or more gaseous laser stages and one or more free electron stages. Each of the free electron laser stages is sequentially pumped by a microwave linear accelerator. Subsequently, the electron beam is directed through a gaseous laser, in the preferred embodiment, and in an alternative embodiment, through a microwave accelerator to lower the energy level of the electron beam to pump one or more gaseous lasers. The combination laser provides high pulse repetition frequencies, on the order of 1 kHz or greater, high power capability, high efficiency, and tunability in the synchronous production of multiple beams of coherent optical radiation.

Brau, Charles A. (Los Alamos, NM); Rockwood, Stephen D. (Los Alamos, NM); Stein, William E. (Los Alamos, NM)

1980-01-01T23:59:59.000Z

73

Excimer kinetics and multiline model for the electron-beam pumped XeF(B-X) laser  

SciTech Connect

A physical model of the time-, temperature- and wavelength-dependent behavior of an E-beam pumped XeF(B-X) laser is developed. Correlations with published laser- and fluorescence-efficiency data, laser spectra, gain, and absorption data are discussed.

Blauer, J.A.; Yang, T.T.; Turner C.E. Jr.; Copeland, D.A.

1984-12-01T23:59:59.000Z

74

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

SciTech Connect

A plasma decelerating stage is investigated as a compact alternative for the disposal of high-energy beams (beam dumps). This could benefit the design of laser-driven plasma accelerator (LPA) applications that require transportability and or high-repetition-rate operation regimes. Passive and laser-driven (active) plasma-based beam dumps are studied analytically and with particle-in-cell (PIC) simulations in a 1D geometry. Analytical estimates for the beam energy loss are compared to and extended by the PIC simulations, showing that with the proposed schemes a beam can be efficiently decelerated in a centimeter-scale distance.

Bonatto, A.; Schroeder, C.B.; Vay, J.-L.; Geddes, C.R.; Benedetti, C.; Esarey and, E.; Leemans, W.P.

2014-07-13T23:59:59.000Z

75

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

SciTech Connect

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

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

2014-04-28T23:59:59.000Z

76

Low Emittance Electron Beam Studies  

SciTech Connect

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

Tikhoplav, Rodion; /Rochester U.; ,

2006-04-01T23:59:59.000Z

77

Laser acceleration of ion beams  

E-Print Network (OSTI)

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

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

2007-02-01T23:59:59.000Z

78

Limits to Electron Beam Emittance from Stochastic Coulomb Interactions  

SciTech Connect

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

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

2008-08-22T23:59:59.000Z

79

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

E-Print Network (OSTI)

beam position monitor (BPM) will be presented. Knowledge ofdiscussed. The deployed BPM [16, 17] consists of a microwaveimportant to note that such a BPM by itself cannot be used

Osterhoff, Jens

2012-01-01T23:59:59.000Z

80

Free electron laser  

DOE Patents (OSTI)

A high gain, single-pass free electron laser formed of a high brilliance electron injector source, a linear accelerator which imparts high energy to the electron beam, and an undulator capable of extremely high magnetic fields, yet with a very short period. The electron injector source is the first stage (gap) of the linear accelerator or a radial line transformer driven by fast circular switch. The linear accelerator is formed of a plurality of accelerating gaps arranged in series. These gaps are energized in sequence by releasing a single pulse of energy which propagates simultaneously along a plurality of transmission lines, each of which feeds the gaps. The transmission lines are graduated in length so that pulse power is present at each gap as the accelerated electrons pass therethrough. The transmission lines for each gap are open circuited at their ends. The undualtor has a structure similar to the accelerator, except that the transmission lines for each gap are substantially short circuited at their ends, thus converting the electric field into magnetic field. A small amount of resistance is retained in order to generate a small electric field for replenishing the electron bunch with the energy lost as it traverses through the undulator structure.

Villa, Francesco (Alameda, CA)

1990-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

Generation of quasi-monochromatic beams of accelerated electrons during interaction of weak-contrast intense femtosecond laser radiation with a metal-foil edge  

SciTech Connect

The formation of monoenergetic beams of accelerated electrons by focusing femtosecond laser radiation with an intensity of 2 Multiplication-Sign 10{sup 17} W cm{sup -2} onto an edge of aluminium foil has been experimentally demonstrated. The electrons had energy distributions peaking in the range from 0.2 to 0.8 MeV and an energy spread less than 20 %. The acceleration mechanism related to the generation of a plasma wave as a result of self-modulation instability of the laser pulse in the subcritical plasma formed the prepulse of the laser system (arriving 10 ns before the main pulse) is considered. Onedimensional PIC simulation of the interaction between the laser radiation and plasma with a concentration of 5 Multiplication-Sign 10{sup 19} cm{sup -3} showed that effective excitation of a plasma wave, as well as the trapping and acceleration of the electron beam with an energy on the order of 1 MeV, may occur in the presence of inhomogeneities in the density at the plasma boundary and in the temporal shape of the beam. (extreme light fields and their applications)

Malkov, Yu A; Stepanov, A N; Yashunin, D A; Pugachev, L P; Levashov, P R; Andreev, N E; Andreev, Aleksandr A

2013-03-31T23:59:59.000Z

82

Two-dimensional optimization of free-electron-laser designs  

DOE Patents (OSTI)

Off-axis, two-dimensional designs for free electron lasers are described that maintain correspondence of a light beam with a synchronous electron at an optimal transverse radius r > 0 to achieve increased beam trapping efficiency and enhanced laser beam wavefront control so as to decrease optical beam diffraction and other deleterious effects.

Prosnitz, D.; Haas, R.A.

1982-05-04T23:59:59.000Z

83

Two-dimensional optimization of free electron laser designs  

DOE Patents (OSTI)

Off-axis, two-dimensional designs for free electron lasers that maintain correspondence of a light beam with a "synchronous electron" at an optimal transverse radius r>0 to achieve increased beam trapping efficiency and enhanced laser beam wavefront control so as to decrease optical beam diffraction and other deleterious effects.

Prosnitz, Donald (Walnut Creek, CA); Haas, Roger A. (Pleasanton, CA)

1985-01-01T23:59:59.000Z

84

Electron Beam Ion Sources  

E-Print Network (OSTI)

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

Zschornacka, G; Thorn, A

2013-01-01T23:59:59.000Z

85

Development of a Silicon Based Electron Beam Transmission Window for Use in a KrF Excimer Laser System  

SciTech Connect

The Princeton Plasma Physics Laboratory (PPPL), in collaboration with the Naval Research Laboratory (NRL), is currently investigating various novel materials (single crystal silicon, <100>, <110> and <111>) for use as electron-beam transmission windows in a KrF excimer laser system. The primary function of the window is to isolate the active medium (excimer gas) from the excitation mechanism (field-emission diodes). Chosen window geometry must accommodate electron energy transfer greater than 80% (750 keV), while maintaining structural integrity during mechanical load (1.3 to 2.0 atm base pressure differential, approximate 0.5 atm cyclic pressure amplitude, 5 Hz repetition rate) and thermal load across the entire hibachi area (approximate 0.9 W {center_dot} cm superscript ''-2''). In addition, the window must be chemically resistant to attack by fluorine free-radicals (hydrofluoric acid, secondary). In accordance with these structural, functional, and operational parameters, a 22.4 mm square silicon prototype window, coated with 500 nm thin-film silicon nitride (Si{sub 3}N{sub 4}), has been fabricated. The window consists of 81 square panes with a thickness of 0.019 mm {+-} 0.001 mm. Stiffened (orthogonal) sections are 0.065 mm in width and 0.500 mm thick (approximate). Appended drawing (Figure 1) depicts the window configuration. Assessment of silicon (and silicon nitride) material properties and CAD modeling and analysis of the window design suggest that silicon may be a viable solution to inherent parameters and constraints.

C.A. Gentile; H.M. Fan; J.W. Hartfield; R.J. Hawryluk; F. Hegeler; P.J. Heitzenroeder; C.H. Jun; L.P. Ku; P.H. LaMarche; M.C. Myers; J.J. Parker; R.F. Parsells; M. Payen; S. Raftopoulos; J.D. Sethian

2002-11-21T23:59:59.000Z

86

Optical wavelength modulation in free electron lasers  

SciTech Connect

An attribute of the free electron laser (FEL) is the continuous tunability of the optical wavelength by modulation of the electron beam energy. The variation of the wavelength and power of the optical beam is studied as a function of FEL operating parameters. These results will be applied to the Stanford SCA FEL and Boeing FEL.

Mabe, R.M.; Wong, R.K.; Colson, W.B. [Naval Postgraduate School, Monterey, CA (United States)

1995-12-31T23:59:59.000Z

87

Protective laser beam viewing device  

DOE Patents (OSTI)

A protective laser beam viewing system or device including a camera selectively sensitive to laser light wavelengths and a viewing screen receiving images from the laser sensitive camera. According to a preferred embodiment of the invention, the camera is worn on the head of the user or incorporated into a goggle-type viewing display so that it is always aimed at the area of viewing interest to the user and the viewing screen is incorporated into a video display worn as goggles over the eyes of the user.

Neil, George R.; Jordan, Kevin Carl

2012-12-18T23:59:59.000Z

88

Short rise time intense electron beam generator  

DOE Patents (OSTI)

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

Olson, C.L.

1984-03-16T23:59:59.000Z

89

Vacuum self-focussing of very intense laser beams  

E-Print Network (OSTI)

We argue that long-range photon-photon attraction induced by the dipole interaction of two electron-positron loops can lead to "vacuum self-focussing" of very intense laser beams. The focussing angle theta(F) is found to increase with the beam intensity I as theta(F) I^(4/3); for the laser beams available at present or in the near future, theta(F) 10^(-10)--10^(-7).

Dmitri Kharzeev; Kirill Tuchin

2007-02-21T23:59:59.000Z

90

High energy laser beam dump  

DOE Patents (OSTI)

The laser beam dump is positioned in a housing. An absorbing glass plate means is operatively connected to the housing. A heat sync means for extracting heat from the absorbing glass plate means is operatively connected to the housing and operatively connected to the absorbing glass plate means.

Halpin, John (Tracy, CA)

2004-09-14T23:59:59.000Z

91

Laser-Accelerated Protons with Energy-Dependent Beam Direction  

Science Journals Connector (OSTI)

The spatial distribution of protons, accelerated by intense femtosecond laser pulses interacting with thin target foils under oblique irradiation are investigated. Under certain conditions, the proton beams are directed away from the target normal. This deviation is towards the laser forward direction, with an angle that increases with the level and duration of the amplified spontaneous emission pedestal before the main laser pulse. In addition, for a given laser pulse, this beam deviation increases with proton energy. The observations are discussed in terms of different electron acceleration mechanisms and target normal sheath acceleration, in combination with a laser-controllable shock wave locally deforming the target rear surface.

F. Lindau; O. Lundh; A. Persson; P. McKenna; K. Osvay; D. Batani; C.-G. Wahlstrm

2005-10-19T23:59:59.000Z

92

SciTech Connect: Compact X-ray Free Electron Laser from a Laser...  

Office of Scientific and Technical Information (OSTI)

Gradient Undulator Compact laser-plasma accelerators can produce high energy electron beams with low emittance, high peak current but a rather large energy spread. The large...

93

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

94

Electron beam machining using rotating and shaped beam power distribution  

DOE Patents (OSTI)

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

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

1996-07-09T23:59:59.000Z

95

Femtosecond electron and x-ray generation by laser and plasma-based sources  

E-Print Network (OSTI)

Although conventional electron sources (photocathode orof these conventional electron sources. Novel schemes which11, 2000 These laser-electron beam sources o?er some unique

Esarey, E.; Leemans, W.P.

2000-01-01T23:59:59.000Z

96

Pair production in counter-propagating laser beams  

E-Print Network (OSTI)

Based on an analysis of a specific electron trajectory in counter-propagating beams, Bell & Kirk (PRL 101, 200403 (2008)) recently suggested that laboratory lasers may shortly be able to produce significant numbers of electron-positron pairs. We confirm their results using an improved treatment of nonlinear Compton scattering in the laser beams. Implementing an algorithm that integrates classical electron trajectories, we then examine a wide range of laser pulse shapes and polarizations. We find that counter-propagating, linearly polarized beams, with either aligned or crossed orientation, are likely to initiate a pair avalanche at intensities of approximately 10^{24} Watts/sq cm per beam. The same result is found by modelling one of the beams as a wave reflected at the surface of an overdense solid.

J. G. Kirk; A. R. Bell; I. Arka

2009-06-24T23:59:59.000Z

97

Kinetically tailored properties of electron-beam excited XeF(C. -->. A) and XeF(B. -->. X) laser media using an Ar-Kr buffer mixture  

SciTech Connect

Use of a two-component buffer gas comprised of Ar and Kr results in electron-beam excited XeF(C..-->..A) laser pulse energy and intrinsic efficiency values comparable to those of UV rare gas-halide lasers. Herein the authors report measurements of transient absorption confirming that the primary effect of a buffer comprised of Ar and Kr is a significantly lower level of ionized and excited species that absorb in the blue-green spectral region. Spectral analysis of a variety of mixtures show that the Ar-Kr buffer also benefits XeF(C..-->..A) laser performance due to an increase in gain in the 400-450 nm region caused by the presence of the Kr/sub 2/F excimer. In addition, a large increase in absorption at --351 nm, also due to Kr/sub 2/F, suppresses oscillation on the competitive XeF(B..-->..X) transition and, for certain conditions, makes efficient simultaneous oscillation of the XeF(B..-->..X) and XeF(C..-->..A) laser transitions possible.

Nighan, W.L.; Sauerbrey, R.A.; Zhu, Y.; Tittel, F.K.; Wilson, W.L. Jr.

1987-02-01T23:59:59.000Z

98

Scattering apodizer for laser beams  

DOE Patents (OSTI)

A method is disclosed for apodizing a laser beam to smooth out the production of diffraction peaks due to optical discontinuities in the path of the laser beam, such method comprising introduction of a pattern of scattering elements for reducing the peak intensity in the region of such optical discontinuities, such pattern having smoothly tapering boundaries in which the distribution density of the scattering elements is tapered gradually to produce small gradients in the distribution density, such pattern of scattering elements being effective to reduce and smooth out the diffraction effects which would otherwise be produced. The apodizer pattern may be produced by selectively blasting a surface of a transparent member with fine abrasive particles to produce a multitude of minute pits. In one embodiment, a scattering apodizer pattern is employed to overcome diffraction patterns in a multiple element crystal array for harmonic conversion of a laser beam. The interstices and the supporting grid between the crystal elements are obscured by the gradually tapered apodizer pattern of scattering elements.

Summers, Mark A. (Livermore, CA); Hagen, Wilhelm F. (Livermore, CA); Boyd, Robert D. (Livermore, CA)

1985-01-01T23:59:59.000Z

99

Scattering apodizer for laser beams  

DOE Patents (OSTI)

A method is disclosed for apodizing a laser beam to smooth out the production of diffraction peaks due to optical discontinuities in the path of the laser beam, such method comprising introduction of a pattern of scattering elements for reducing the peak intensity in the region of such optical discontinuities, such pattern having smoothly tapering boundaries in which the distribution density of the scattering elements is tapered gradually to produce small gradients in the distribution density, such pattern of scattering elements being effective to reduce and smooth out the diffraction effects which would otherwise be produced. The apodizer pattern may be produced by selectively blasting a surface of a transparent member with fine abrasive particles to produce a multitude of minute pits. In one embodiment, a scattering apodizer pattern is employed to overcome diffraction patterns in a multiple element crystal array for harmonic conversion of a laser beam. The interstices and the supporting grid between the crystal elements are obscured by the gradually tapered apodizer pattern of scattering elements.

Summers, M.A.; Hagen, W.F.; Boyd, R.D.

1984-01-01T23:59:59.000Z

100

Cascaded injection resonator for coherent beam combining of laser arrays  

DOE Patents (OSTI)

The invention provides a cascaded injection resonator for coherent beam combining of laser arrays. The resonator comprises a plurality of laser emitters arranged along at least one plane and a beam sampler for reflecting at least a portion of each laser beam that impinges on the beam sampler, the portion of each laser beam from one of the laser emitters being reflected back to another one of the laser emitters to cause a beam to be generated from the other one of the laser emitters to the beam reflector. The beam sampler also transmits a portion of each laser beam to produce a laser output beam such that a plurality of laser output beams of the same frequency are produced. An injection laser beam is directed to a first laser emitter to begin a process of generating and reflecting a laser beam from one laser emitter to another laser emitter in the plurality. A method of practicing the invention is also disclosed.

Kireev, Vassili [Sunnyvale, CA; Liu, Yun; Protopopescu, Vladimir [Knoxville, TN; Braiman, Yehuda [Oak Ridge, TN

2008-10-21T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

Simulation of a high-gain tapered-wiggler free-electron laser  

SciTech Connect

We present results from a numerical model of a high-gain (electron-beam power > input laser beam power) FEL amplifier.

Fawley, W.M.; Scharlemann, E.T.; Prosnitz, D.

1983-09-27T23:59:59.000Z

102

High-Power Laser Beam Cladding  

Science Journals Connector (OSTI)

This paper reports major advances in the understanding, refinement and application of high-power laser beam cladding. The most important relationships between essential laser process variables and clad characteri...

G. J. Bruck

1987-02-01T23:59:59.000Z

103

Laser acceleration of quasi-monoenergetic MeV ion beams  

Science Journals Connector (OSTI)

... S. et al. Electron, photon, and ion beams from the relativistic interaction of Petawatt laser pulses with solid targets. Phys. Plasmas 5, 20762082 (2000)

B. M. Hegelich; B. J. Albright; J. Cobble; K. Flippo; S. Letzring; M. Paffett; H. Ruhl; J. Schreiber; R. K. Schulze; J. C. Fernndez

2006-01-26T23:59:59.000Z

104

Energy characteristics of an electron-beam-controlled atmospheric-pressure CO/sub 2/ laser utilizing CO/sub 2/--N/sub 2/--H/sub 2/O mixtures  

SciTech Connect

An experimental investigation was made of the energy characteristics of a pulsed electron-beam-controlled atmospheric-pressure CO/sub 2/ laser utilizing CO/sub 2/--N/sub 2/--H/sub 2/O mixtures as a function of the gas mixture composition, of the electric field strength, and of the specific pump power. The energy parameters of the laser were calculated for the experimental conditions. Qualitative and quantitative agreement was obtained between the calculated and experimentally measured data.

Krasyukov, A.G.; Likhanskii, V.V.; Naumov, V.G.; Panchenko, Y.M.; Petrushevich, Y.V.; Pis'mennyi, V.D.; Shachkin, L.V.

1983-07-01T23:59:59.000Z

105

Coherence delay augmented laser beam homogenizer  

DOE Patents (OSTI)

The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.

Rasmussen, P.; Bernhardt, A.

1993-06-29T23:59:59.000Z

106

Coherence delay augmented laser beam homogenizer  

DOE Patents (OSTI)

The geometrical restrictions on a laser beam homogenizer are relaxed by ug a coherence delay line to separate a coherent input beam into several components each having a path length difference equal to a multiple of the coherence length with respect to the other components. The components recombine incoherently at the output of the homogenizer, and the resultant beam has a more uniform spatial intensity suitable for microlithography and laser pantogography. Also disclosed is a variable aperture homogenizer, and a liquid filled homogenizer.

Rasmussen, Paul (Livermore, CA); Bernhardt, Anthony (Berkeley, CA)

1993-01-01T23:59:59.000Z

107

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

SciTech Connect

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

Elmer, J W

2009-01-23T23:59:59.000Z

108

following an electron bunch for free electron laser  

SciTech Connect

A video artist's ultra-slow-motion impression of an APEX-style electron gun firing a continuous train of electron bunches into a superconducting linear accelerator (in reality this would happen a million times a second). As they approach the speed of light the bunches contract, maintaining beam quality. After acceleration, the electron bunches are diverted into one or more undulators, the key components of free electron lasers. Oscillating back and forth in the changing magnetic field, they create beams of structured x-ray pulses. Before entering the experimental areas the electron bunches are diverted to a beam dump. (Animation created by Illumina Visual, http://www.illuminavisual.com/, for Lawrence Berkeley National Laboratory. Music for this excerpt, "Feeling Dark (Behind The Mask)" is by 7OOP3D http://ccmixter.org/files/7OOP3D/29126 and is licensed under a Creative Commons license: http://creativecommons.org/licenses/by-nc/3.0/)

None

2012-01-01T23:59:59.000Z

109

Effect of deposition temperature on electron-beam evaporated polycrystalline silicon thin-film and crystallized by diode laser  

SciTech Connect

The effects of the deposition temperature on the microstructure, crystallographic orientation, and electrical properties of a 10-?m thick evaporated Si thin-film deposited on glass and crystallized using a diode laser, are investigated. The crystallization of the Si thin-film is initiated at a deposition temperature between 450 and 550?C, and the predominant (110) orientation in the normal direction is found. Pole figure maps confirm that all films have a fiber texture and that it becomes stronger with increasing deposition temperature. Diode laser crystallization is performed, resulting in the formation of lateral grains along the laser scan direction. The laser power required to form lateral grains is higher in case of films deposited below 450?C for all scan speeds. Pole figure maps show 75% occupancies of the (110) orientation in the normal direction when the laser crystallized film is deposited above 550?C. A higher density of grain boundaries is obtained when the laser crystallized film is deposited below 450?C, which limits the solar cell performance by n?=?2 recombination, and a performance degradation is expected due to severe shunting.

Yun, J., E-mail: j.yun@unsw.edu.au; Varalmov, S.; Huang, J.; Green, M. A. [School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, New South Wales 2052 (Australia); Kim, K. [School of Photovoltaic and Renewable Energy Engineering, University of New South Wales, Sydney, New South Wales 2052 (Australia); Suntech R and D Australia, Botany, New South Wales 2019 (Australia)

2014-06-16T23:59:59.000Z

110

Staging laser plasma accelerators for increased beam energy  

E-Print Network (OSTI)

Staging Laser Plasma Accelerators for Increased Beam EnergyStaging laser plasma accelerators is an efficient way ofcompact laser-plasma accelerators to generate particle

Panasenko, Dmitriy

2010-01-01T23:59:59.000Z

111

Laser power beaming applications and technology  

SciTech Connect

Beaming laser energy to spacecraft has important economic potential. It promises significant reduction in the cost of access to space, for commercial and government missions. While the potential payoff is attractive, existing technologies perform the same missions and the keys to market penetration for power beaming are a competitive cost and a schedule consistent with customers` plans. Rocketdyne is considering these questions in the context of a commercial enterprise -- thus, evaluation of the requirements must be done based on market assessments and recognition that significant private funding will be involved. It is in the context of the top level business considerations that the technology requirements are being assessed and the program being designed. These considerations result in the essential elements of the development program. Since the free electron laser is regarded as the ``long pole in the tent``, this paper summarizes Rocketdyne`s approach for a timely, cost-effective program to demonstrate an FEL capable of supporting an initial operating capability (IOC).

Burke, R.J.; Cover, R.A.; Curtin, M.S.; Dinius, R.W.; Lampel, M.C. [Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Division

1994-12-31T23:59:59.000Z

112

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

113

Laser Electron Gamma Source. Biennial progress report  

SciTech Connect

The LEGS facility provides intense, polarized, monochromatic {gamma}-ray beams by Compton backscattering laser light from relativistic electrons circulating in the X-Ray storage ring of the National Synchrotron Light Source (NSLS) at Brookhaven National Laboratory. With the start of ring operations at 2.8 GeV, LEGS {gamma}-ray energies now extend to 370 MeV. Considerable progress has been made in the development of a new laser system that will increase the beam energies to 470 MeV, and this system is expected to come into operation before the next biennial report. The total flux is administratively held at 6 {times} 10{sup 6} s{sup {minus}1}. The {gamma}-ray energy is determined, with a resolution of 5.5 MeV, by detecting the scattering electrons in a magnetic spectrometer. This spectrometer can `tag` all {gamma}-rays with energies from 185 MeV up to the Compton edge. The beam spot size at the target position is 8 mm (V) {times} 18 mm (H), FWHM. For a single laser wavelength, the linear polarization of the beam is 98% at the Compton edge and decreases to 50% at about 1/2 the energy of the edge. By choosing the laser wavelengths appropriately the polarization can be maintained above 85% throughout the tagging range. During the last two years, experimental running at LEGS occupied an average of 3000 hours annually. Highlights of some of the programs are discussed below.

Sandorfi, A.M. [ed.; Caracappa, A.; Kuczewski, A.; Kistner, O.C.; Lincoln, F.; Miceli, L.; Thorn, C.E. [Brookhaven National Lab., Upton, NY (United States); Hoblit, S. [Univ. of Virginia, Charlottesville, VA (United States). Dept. of Physics; Khandaker, M. [Brookhaven National Lab., Upton, NY (United States)]|[Virginia Polytechnic Institute & State Univ., Blacksburg, VA (United States). Dept. of Physics

1994-06-01T23:59:59.000Z

114

Free electron laser amplifier driven by an induction linac  

SciTech Connect

This paper discusses the use of a free-electron laser amplifier as a means of converting the kinetic energy of an electron beam into coherent radiation. In particular, the use of an induction linear accelerator is discussed. The motion of the elections in the tapered and untapered wiggler magnets is discussed as well as the beam emittance, and the radiation fields involved. (LSP)

Neil, V.K.

1986-06-03T23:59:59.000Z

115

Feasibility study of a laser ion source for primary ion injection into the Relativistic Heavy Ion Collider electron beam ion sourcea...  

E-Print Network (OSTI)

Collider electron beam ion sourcea... Takeshi Kanesue Department of Applied Quantum Physics and Nuclear Okamura Collider-Accelerator Department, Brookhaven National Laboratory, Upton, New York 11973, USA are in the vacuum of about 10-4 Pa and are isolated from the rest of the beam line to allow the extraction of ions

116

Laser beam reflection from shock waves in xenon and silicon  

Science Journals Connector (OSTI)

The experimental results of the laser beam (?=1 06 ?m) reflection from shock waves in xenon at P=1 6+17 GPa and in silicon at an insulator?metal transition region at P=10+46 GPa are presented. Reflection characteristics and possibility of the estimation of the electron properties of the substance under high pressures are discussed.

V. B. Mintsev; Yu. B. Zaporoghets; V. E. Fortov

1990-01-01T23:59:59.000Z

117

Transverse spreading of electrons in high-intensity laser fields  

E-Print Network (OSTI)

We show that for collisions of electrons with a high-intensity laser, discrete photon emissions introduce a transverse beam spread which is distinct from that due to classical (or beam shape) effects. Via numerical simulations, we show that this quantum induced transverse momentum gain of the electron is manifest in collisions with a realistic laser pulse of intensity within reach of current technology, and we propose it as a measurable signature of strong-field quantum electrodynamics.

D. G. Green; C. N. Harvey

2014-03-18T23:59:59.000Z

118

Beam current controller for laser ion source  

DOE Patents (OSTI)

The present invention relates to the design and use of an ion source with a rapid beam current controller for experimental and medicinal purposes. More particularly, the present invention relates to the design and use of a laser ion source with a magnetic field applied to confine a plasma flux caused by laser ablation.

Okamura, Masahiro

2014-10-28T23:59:59.000Z

119

Ponderomotive self-focusing of Gaussian laser beam in warm collisional plasma  

SciTech Connect

The propagation characteristics of a Gaussian laser beam through warm collisional plasma are investigated by considering the ponderomotive force nonlinearity and the complex eikonal function. By introducing the dielectric permittivity of warm unmagnetized plasma and using the WKB and paraxial ray approximations, the coupled differential equations defining the variations of laser beam parameters are obtained and solved numerically. Effects of laser and plasma parameters such as the collision frequency, the initial laser intensity and its spot size on the beam width parameter and the axis laser intensity distribution are analyzed. It is shown that, self-focusing of the laser beam takes place faster by increasing the collision frequency and initial laser spot size and then after some distance propagation the laser beam abruptly loses its initial diameter and vastly diverges. Furthermore, the modified electron density distribution is obtained and the collision frequency effect on this distribution is studied.

Jafari Milani, M. R., E-mail: mrj.milani@gmail.com [Plasma Physics Research School, Tehran (Iran, Islamic Republic of); Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Niknam, A. R., E-mail: a-niknam@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of); Farahbod, A. H. [Plasma Physics Research School, Tehran (Iran, Islamic Republic of)

2014-06-15T23:59:59.000Z

120

Apparatus and method for laser beam diagnosis  

DOE Patents (OSTI)

An apparatus and method is disclosed for accurate, real time monitoring of the wavefront curvature of a coherent laser beam. Knowing the curvature, it can be quickly determined whether the laser beam is collimated, or focusing (converging), or de-focusing (diverging). The apparatus includes a lateral interferometer for forming an interference pattern of the laser beam to be diagnosed. The interference pattern is imaged to a spatial light modulator (SLM), whose output is a coherent laser beam having an image of the interference pattern impressed on it. The SLM output is focused to obtain the far-field diffraction pattern. A video camera, such as CCD, monitors the far-field diffraction pattern, and provides an electrical output indicative of the shape of the far-field pattern. Specifically, the far-field pattern comprises a central lobe and side lobes, whose relative positions are indicative of the radius of curvature of the beam. The video camera's electrical output may be provided to a computer which analyzes the data to determine the wavefront curvature of the laser beam.

Salmon, Jr., Joseph T. (Livermore, CA)

1991-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

Apparatus and method for laser beam diagnosis  

DOE Patents (OSTI)

An apparatus and method are disclosed for accurate, real time monitoring of the wavefront curvature of a coherent laser beam. Knowing the curvature, it can be quickly determined whether the laser beam is collimated, or focusing (converging), or de-focusing (diverging). The apparatus includes a lateral interferometer for forming an interference pattern of the laser beam to be diagnosed. The interference pattern is imaged to a spatial light modulator (SLM), whose output is a coherent laser beam having an image of the interference pattern impressed on it. The SLM output is focused to obtain the far-field diffraction pattern. A video camera, such as CCD, monitors the far-field diffraction pattern, and provides an electrical output indicative of the shape of the far-field pattern. Specifically, the far-field pattern comprises a central lobe and side lobes, whose relative positions are indicative of the radius of curvature of the beam. The video camera's electrical output may be provided to a computer which analyzes the data to determine the wavefront curvature of the laser beam. 11 figures.

Salmon, J.T. Jr.

1991-08-27T23:59:59.000Z

122

Electron Beam--21st Century Food Technology  

E-Print Network (OSTI)

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

Vestal, Andy

2003-03-07T23:59:59.000Z

123

MIS-1 electron-beam ion source  

Science Journals Connector (OSTI)

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

V. G. Abdulmanov; N. S. Dikansky

2010-12-01T23:59:59.000Z

124

In situ laser processing in a scanning electron microscope  

SciTech Connect

Laser delivery probes using multimode fiber optic delivery and bulk focusing optics have been constructed and used for performing materials processing experiments within scanning electron microscope/focused ion beam instruments. Controlling the current driving a 915-nm semiconductor diode laser module enables continuous or pulsed operation down to sub-microsecond durations, and with spot sizes on the order of 50 {micro}m diameter, achieving irradiances at a sample surface exceeding 1 MW/cm{sup 2}. Localized laser heating has been used to demonstrate laser chemical vapor deposition of Pt, surface melting of silicon, enhanced purity, and resistivity via laser annealing of Au deposits formed by electron beam induced deposition, and in situ secondary electron imaging of laser induced dewetting of Au metal films on SiO{sub x}.

Roberts, Nicholas [University of Tennessee, Knoxville (UTK); Fowlkes, Jason Davidson [ORNL; Rack, Prof. Philip [University of Tennessee, Knoxville (UTK); Moore, Tom [OmniProbe, Inc.; Magel, Greg [OmniProbe, Inc.; Hartfield, Cheryl [OmniProbe, Inc.

2012-01-01T23:59:59.000Z

125

In situ laser processing in a scanning electron microscope  

SciTech Connect

Laser delivery probes using multimode fiber optic delivery and bulk focusing optics have been constructed and used for performing materials processing experiments within scanning electron microscope/focused ion beam instruments. Controlling the current driving a 915-nm semiconductor diode laser module enables continuous or pulsed operation down to sub-microsecond durations, and with spot sizes on the order of 50 {mu}m diameter, achieving irradiances at a sample surface exceeding 1 MW/cm{sup 2}. Localized laser heating has been used to demonstrate laser chemical vapor deposition of Pt, surface melting of silicon, enhanced purity, and resistivity via laser annealing of Au deposits formed by electron beam induced deposition, and in situ secondary electron imaging of laser induced dewetting of Au metal films on SiO{sub x}.

Roberts, Nicholas A.; Magel, Gregory A.; Hartfield, Cheryl D.; Moore, Thomas M.; Fowlkes, Jason D.; Rack, Philip D. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States) and Omniprobe, Inc., an Oxford Instruments Company, 10410 Miller Rd., Dallas, Texas 75238 (United States); Omniprobe, Inc., an Oxford Instruments Company, 10410 Miller Rd., Dallas, Texas 75238 (United States); Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States) and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2012-07-15T23:59:59.000Z

126

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

E-Print Network (OSTI)

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

Liska, Richard

127

Method and apparatus for laser-controlled proton beam radiology  

DOE Patents (OSTI)

A proton beam radiology system provides cancer treatment and proton radiography. The system includes an accelerator for producing an H.sup.- beam and a laser source for generating a laser beam. A photodetachment module is located proximate the periphery of the accelerator. The photodetachment module combines the H.sup.- beam and laser beam to produce a neutral beam therefrom within a subsection of the H.sup.- beam. The photodetachment module emits the neutral beam along a trajectory defined by the laser beam. The photodetachment module includes a stripping foil which forms a proton beam from the neutral beam. The proton beam is delivered to a conveyance segment which transports the proton beam to a patient treatment station. The photodetachment module further includes a laser scanner which moves the laser beam along a path transverse to the cross-section of the H.sup.- beam in order to form the neutral beam in subsections of the H.sup.- beam. As the scanning laser moves across the H.sup.- beam, it similarly varies the trajectory of the proton beam emitted from the photodetachment module and in turn varies the target location of the proton beam upon the patient. Intensity modulation of the proton beam can also be achieved by controlling the output of the laser.

Johnstone, Carol J. (Warrenville, IL)

1998-01-01T23:59:59.000Z

128

Method and apparatus for laser-controlled proton beam radiology  

DOE Patents (OSTI)

A proton beam radiology system provides cancer treatment and proton radiography. The system includes an accelerator for producing an H{sup {minus}} beam and a laser source for generating a laser beam. A photodetachment module is located proximate the periphery of the accelerator. The photodetachment module combines the H{sup {minus}} beam and laser beam to produce a neutral beam therefrom within a subsection of the H{sup {minus}} beam. The photodetachment module emits the neutral beam along a trajectory defined by the laser beam. The photodetachment module includes a stripping foil which forms a proton beam from the neutral beam. The proton beam is delivered to a conveyance segment which transports the proton beam to a patient treatment station. The photodetachment module further includes a laser scanner which moves the laser beam along a path transverse to the cross-section of the H{sup {minus}} beam in order to form the neutral beam in subsections of the H{sup {minus}} beam. As the scanning laser moves across the H{sup {minus}} beam, it similarly varies the trajectory of the proton beam emitted from the photodetachment module and in turn varies the target location of the proton beam upon the patient. Intensity modulation of the proton beam can also be achieved by controlling the output of the laser. 9 figs.

Johnstone, C.J.

1998-06-02T23:59:59.000Z

129

Density gradient free electron collisionally excited X-ray laser  

DOE Patents (OSTI)

An operational X-ray laser (30) is provided that amplifies 3p-3s transition X-ray radiation along an approximately linear path. The X-ray laser (30) is driven by a high power optical laser. The driving line focused optical laser beam (32) illuminates a free-standing thin foil (34) that may be associated with a substrate (36) for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the X-ray laser gain medium. The X-ray laser (30) may be driven by more than one optical laser beam (32, 44). The X-ray laser (30) has been successfully demonstrated to function in a series of experimental tests.

Campbell, Edward M. (Pleasanton, CA); Rosen, Mordecai D. (Berkeley, CA)

1989-01-01T23:59:59.000Z

130

Density gradient free electron collisionally excited x-ray laser  

DOE Patents (OSTI)

An operational x-ray laser is provided that amplifies 3p-3s transition x-ray radiation along an approximately linear path. The x-ray laser is driven by a high power optical laser. The driving line focused optical laser beam illuminates a free-standing thin foil that may be associated with a substrate for improved structural integrity. This illumination produces a generally cylindrically shaped plasma having an essentially uniform electron density and temperature, that exists over a long period of time, and provides the x-ray laser gain medium. The x-ray laser may be driven by more than one optical laser beam. The x-ray laser has been successfully demonstrated to function in a series of experimental tests.

Campbell, E.M.; Rosen, M.D.

1984-11-29T23:59:59.000Z

131

Direct particle acceleration by two identical crossed radially polarized laser beams  

SciTech Connect

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

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

2010-07-15T23:59:59.000Z

132

LASER-ELECTRON COMPTON INTERACTION IN PLASMA CHANNELS  

SciTech Connect

A concept of high intensity femtosecond laser synchrotron source (LSS) is based on Compton backscattering of focused electron and laser beams. The short Rayleigh length of the focused laser beam limits the length of interaction to a few picoseconds. However, the technology of the high repetition rate high-average power picosecond lasers required for high put through LSS applications is not developed yet. Another problem associated with the picosecond laser pulses is undesirable nonlinear effects occurring when the laser photons are concentrated in a short time interval. To avoid the nonlinear Compton scattering, the laser beam has to be split, and the required hard radiation flux is accumulated over a number of consecutive interactions that complicates the LSS design. In order to relieve the technological constraints and achieve a practically feasible high-power laser synchrotron source, we propose to confine the laser-electron interaction region in the extended plasma channel. This approach permits to use nanosecond laser pulses instead of the picosecond pulses. That helps to avoid the nonlinear Compton scattering regime and allows to utilize already existing technology of the high-repetition rate TEA CO{sub 2} lasers operating at the atmospheric pressure. We demonstrate the advantages of the channeled LSS approach by the example of the prospective polarized positron source for Japan Linear Collider.

POGORELSKY,I.V.

1998-10-01T23:59:59.000Z

133

Quantum electrodynamics in a laser and the electron laser collision  

E-Print Network (OSTI)

Quantum electrodynamics in a laser is formulated, in which the electron-laser interaction is exactly considered, while the interaction of an electron and a single photon is considered by perturbation. The formulation is applied to the electron-laser collisions. The effect of coherence between photons in the laser is therefore fully considered in these collisions. The possibility of $\\gamma-$ray laser generation by use of this kind of collision is discussed.

Qi-Ren Zhang

2014-08-08T23:59:59.000Z

134

Nonlinear formation of holographic images of obscurations in laser beams  

E-Print Network (OSTI)

Nonlinear formation of holographic images of obscurations in laser beams C. Clay Widmayer, David of obscurations in laser beams. The predictions of the model are found to be in good agreement with measurements the intensity and fluence of the beam at each component in the laser chain. Dam- age threats to the system can

135

Volkov solution for two laser beams and ITER  

E-Print Network (OSTI)

We find the solution of the Dirac equation for two plane waves (laser beams) and we determine the modified Compton formula for the scattering of two photons on an alectron. The practical meaning of the two laser beams is, that two laser beams impinging on a targed which is constituted from material in the form of a foam, can replace 100-200 laser beams impinging on a normal targed. It means that the nuclear fusion with two laser beams is realistic in combination with the nuclear reactor such as ITER.

Miroslav Pardy

2005-07-12T23:59:59.000Z

136

Electron  

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

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

137

Quasi-monoenergetic electron beams production in a sharp density transition  

SciTech Connect

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

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

2012-09-10T23:59:59.000Z

138

Optics of electron beam in the Recycler  

SciTech Connect

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

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

2005-11-01T23:59:59.000Z

139

A Micromachined Electron Beam Ion Source  

Science Journals Connector (OSTI)

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

G. Petzold; P. Siebert; J. Mller

2000-01-01T23:59:59.000Z

140

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

DOE Patents (OSTI)

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

Neil, G.R.

1996-07-30T23:59:59.000Z

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


141

Saturation of multi-laser beams laser-plasma instabilities from stochastic ion heating  

SciTech Connect

Cross-beam energy transfer (CBET) has been used as a tool on the National Ignition Facility (NIF) since the first energetics experiments in 2009 to control the energy deposition in ignition hohlraums and tune the implosion symmetry. As large amounts of power are transferred between laser beams at the entrance holes of NIF hohlraums, the presence of many overlapping beat waves can lead to stochastic ion heating in the regions where laser beams overlap [P. Michel et al., Phys. Rev. Lett. 109, 195004 (2012)]. This increases the ion acoustic velocity and modifies the ion acoustic waves dispersion relation, thus reducing the plasma response to the beat waves and the efficiency of CBET. This pushes the plasma oscillations driven by CBET in a regime where the phase velocities are much smaller than both the electron and ion thermal velocities. CBET gains are derived for this new regime and generalized to the case of multi ion species plasmas.

Michel, P.; Williams, E. A.; Divol, L.; Berger, R. L.; Glenzer, S. H.; Callahan, D. A. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States); Rozmus, W. [Theoretical Physics Institute, University of Alberta, Edmonton, Alberta T6G2G7 (Canada) [Theoretical Physics Institute, University of Alberta, Edmonton, Alberta T6G2G7 (Canada); Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

2013-05-15T23:59:59.000Z

142

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

E-Print Network (OSTI)

PLASMA FOCUSING OF HIGH ENERGY DENSITY ELECTRON AND POSITRON BEAMS \\Lambda J.S.T. Ng, P. Chen, W, for the first time, positron beams. We also discuss measure­ ments on plasma lens­induced synchrotron radiation and laser­ and beam­plasma interactions. 1 INTRODUCTION The plasma lens was proposed as a final focusing

143

Intense steady state electron beam generator  

DOE Patents (OSTI)

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

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

1990-01-01T23:59:59.000Z

144

Collaborative Research: Instability and transport of laser beam in plasma  

SciTech Connect

Our goal was to determine the onset of laser light scattering due to plasma wave instabilities. Such scatter is usually regarded as deleterious since laser beam strength is thereby diminished. While this kind of laser-plasma-instability (LPI) has long been understood for the case of coherent laser light, the theory of LPI onset for a laser beam with degraded coherence is recent. Such a laser beam fills plasma with a mottled intensity distribution, which has large fluctuations. The key question is: do the exceptionally large fluctuations control LPI onset or is it controlled by the relatively quiescent background laser intensity? We have answered this question. This is significant because LPI onset power in the former case is typically small compared to that of the latter. In addition, if large laser intensity fluctuations control LPI onset, then nonlinear effects become significant for less powerful laser beams than otherwise estimated.

Rose, Harvey Arnold [New Mexico Consortium; Lushnikov, Pavel [University of New Mexico

2014-11-18T23:59:59.000Z

145

Stationary self-focusing of intense laser beam in cold quantum plasma using ramp density profile  

SciTech Connect

By using a transient density profile, we have demonstrated stationary self-focusing of an electromagnetic Gaussian beam in cold quantum plasma. The paper is devoted to the prospects of using upward increasing ramp density profile of an inhomogeneous nonlinear medium with quantum effects in self-focusing mechanism of high intense laser beam. We have found that the upward ramp density profile in addition to quantum effects causes much higher oscillation and better focusing of laser beam in cold quantum plasma in comparison to that in the classical relativistic case. Our computational results reveal the importance and influence of formation of electron density profiles in enhancing laser self-focusing.

Habibi, M. [Department of Physics, Shirvan Branch, Islamic Azad University, Shirvan (Iran, Islamic Republic of); Ghamari, F. [Department of Physics, Khorramabad Branch, Islamic Azad University, Khorramabad (Iran, Islamic Republic of)

2012-10-15T23:59:59.000Z

146

Laser-seeded modulation instability within LHC proton beams  

SciTech Connect

A new method for seeding the modulation instability (MI) within an SPS-LHC proton beam using a laser pulse is presented. Using simulations, we show that a laser pulse placed ahead of a proton beam excites axially symmetric selfmodulation modes within the proton beam and leads to peak accelerating fields that are comparable to previously proposed seeding methods.

Siemon, Carl; Khudik, Vladimir; Yi, S. Austin; Pukhov, Alexander; Shvets, Gennady [University of Texas at Austin, Austin, Texas 78712 (United States); Max-Planck-Institut fuer Physik, 80805 Muenchen (Germany); University of Texas at Austin, Austin, Texas 78712 (United States)

2012-12-21T23:59:59.000Z

147

Ultra-bright pulsed electron beam with low longitudinal emittance  

DOE Patents (OSTI)

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

Zolotorev, Max (Oakland, CA)

2010-07-13T23:59:59.000Z

148

Status of the visible Free-Electron Laser at the Brookhaven Accelerator Test Facility  

SciTech Connect

The 500 nm Free-Electron Laser (ATF) of the Brookhaven National Laboratory is reviewed. We present an overview of the ATF, a high-brightness, 50-MeV, electron accelerator and laser complex which is a users' facility for accelerator and beam physics. A number of laser acceleration and FEL experiments are under construction at the ATF. The visible FEL experiment is based on a novel superferric 8.8 mm period undulator. The electron beam parameters, the undulator, the optical resonator, optical and electron beam diagnostics are discussed. The operational status of the experiment is presented. 22 refs., 7 figs.

Batchelor, K.; Ben-Zvi, I.; Fernow, R.C.; Fisher, A.S.; Friedman, A.; Gallardo, J.; Ingold, G.; Kirk, H.; Kramer, S.; Lin, L.; Rogers, J.T.; Sheehan, J.F.; van Steenbergen, A.; Woodle, M.; Xie, J.; Yu, L.H.; Zhang, R. (Brookhaven National Lab., Upton, NY (United States)); Bhowmik, A. (Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.)

1991-01-01T23:59:59.000Z

149

Laser systems configured to output a spectrally-consolidated laser beam and related methods  

DOE Patents (OSTI)

A laser apparatus includes a plurality of pumps each of which is configured to emit a corresponding pump laser beam having a unique peak wavelength. The laser apparatus includes a spectral beam combiner configured to combine the corresponding pump laser beams into a substantially spatially-coherent pump laser beam having a pump spectrum that includes the unique peak wavelengths, and first and second selectively reflective elements spaced from each other to define a lasing cavity including a lasing medium therein. The lasing medium generates a plurality of gain spectra responsive to absorbing the pump laser beam. Each gain spectrum corresponds to a respective one of the unique peak wavelengths of the substantially spatially-coherent pump laser beam and partially overlaps with all other ones of the gain spectra. The reflective elements are configured to promote emission of a laser beam from the lasing medium with a peak wavelength common to each gain spectrum.

Koplow, Jeffrey P. (San Ramon, CA)

2012-01-10T23:59:59.000Z

150

Simulation of Modulated Electron Beams in an Rf Electron Gun  

SciTech Connect

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

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

2010-11-04T23:59:59.000Z

151

Expanding Laser Beams: Many times when a laser is used in an optical system,  

E-Print Network (OSTI)

L- L Project#3 Expanding Laser Beams: Many times when a laser is used in an optical system, there is a requirement for either a larger beam or a beam that has a small divergence (doesn't change size over the length of the experiment). In some casesthe size of the beam becomes critical, for example;when measuring

Yu, Jaehoon

152

Cone-shaped beams in selective laser cladding  

Science Journals Connector (OSTI)

A new method of radiation energy introduction into a powder jet for selective laser cladding (SLC) technology is presented, which is ... based on the unique properties of cone-shaped laser beams. The parameters o...

Yu. A. Chivel

2005-01-01T23:59:59.000Z

153

Staging Laser Plasma Accelerators for Increased Beam Energy  

E-Print Network (OSTI)

Staging Laser Plasma Accelerators for Increased Beam Energy D. Panasenko, A. J. Shu, C. B., Berkeley, California 94720, USA Abstract. Staging laser plasma accelerators is an efficient way of mitigating laser pump depletion in laser driven accelerators and necessary for reaching high energies

Geddes, Cameron Guy Robinson

154

DOE Science Showcase - Free-Electron Lasers | OSTI, US Dept of Energy,  

Office of Scientific and Technical Information (OSTI)

Free-Electron Lasers Free-Electron Lasers Free-Electron Lasers absorb and release energy at any wavelength and can be controlled more precisely than conventional lasers by producing intense powerful light in brief bursts with extreme precision. This innovative technology has opened doors to a vast array of possibilities for manufacturing and for basic research. Read more in the white paper In OSTI Collections: Free-Electron Lasers by Dr. William Watson, Physicist, OSTI staff. Free-Electron Lasers Results in DOE Databases Science.gov Ciencia.Science.gov (Español) WorldWideScience.org Energy Citations Database DOE Information Bridge Relevant Subject Clusters FREE ELECTRON LASERS PARTICLE ACCELERATORS ENGINEERING LASERS ELECTRON BEAMS ACCELERATORS WIGGLER MAGNETS EQUIPMENT ELECTROMAGNETIC RADIATION

155

Broadband microwave burst produced by electron beams  

E-Print Network (OSTI)

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

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

2007-12-16T23:59:59.000Z

156

Cryogenic Electron Beam Induced Chemical Etching  

Science Journals Connector (OSTI)

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

Aiden A. Martin; Milos Toth

2014-10-21T23:59:59.000Z

157

The Electron Beam Ion Source (EBIS)  

ScienceCinema (OSTI)

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

Brookhaven Lab

2010-01-08T23:59:59.000Z

158

The Electron Beam Ion Source (EBIS)  

SciTech Connect

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

Brookhaven Lab

2009-06-09T23:59:59.000Z

159

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

160

Electrons and gas versus high brightness ion beams  

E-Print Network (OSTI)

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

2005-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

First operation of the Rocketdyne/Stanford free electron laser  

Science Journals Connector (OSTI)

A near infrared free electron laser (FEL) has been built and installed by Rocketdyne in the Stanford Photon Research Laboratory. The Rocketdyne/Stanford FEL utilizes a very high quality, 2 m long, permanent magnet planar wiggler whose gap may be continuously tuned, and magnetic field axially tapered by varying the gap at one end relative to the other. The laser is operated with an e-beam supplied by the Stanford Mark-III accelerator. A stable resonator with a broadband, dielectric coated element permits transmissive outcoupling over the 2.73.7 ?m wavelength range. Results from initial operation of this laser are presented.

Anup Bhowmik; Mark S. Curtin; Wayne A. McMullin; Stephen V. Benson; John M.J. Madey; Bruce A. Richman; Louis Vintro

1988-01-01T23:59:59.000Z

162

A technique has been developed to accurately align a laser beam through a plasma channel by minimizing the  

E-Print Network (OSTI)

for radiation sources ­ ranging from coherent THz to free electron laser (FEL) x-ray sources and ThomsonAbstract A technique has been developed to accurately align a laser beam through a plasma channel by minimizing the shift in laser centroid and angle at the channel outptut. If only the shift in centroid

Geddes, Cameron Guy Robinson

163

Inverse free electron laser accelerator for advanced light sources  

We discuss the inverse free electron laser (IFEL) scheme as a compact high gradient accelerator solution for driving advanced light sources such as a soft x-ray free electron laser amplifier or an inverse Compton scattering based gamma-ray source. In particular, we present a series of new developments aimed at improving the design of future IFEL accelerators. These include a new procedure to optimize the choice of the undulator tapering, a new concept for prebunching which greatly improves the fraction of trapped particles and the final energy spread, and a self-consistent study of beam loading effects which leads to an energy-efficient high laser-to-beam power conversion.

Duris, J. P.; Musumeci, P.; Li, R. K.

2012-06-01T23:59:59.000Z

164

Holographic generation of highly twisted electron beams  

E-Print Network (OSTI)

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

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

2014-01-01T23:59:59.000Z

165

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

SciTech Connect

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

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

2011-05-13T23:59:59.000Z

166

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

167

High-current-density, high brightness cathodes for free electron laser applications  

SciTech Connect

This report discusses the following topics: brightness and emittance of electron beams and cathodes; general requirements for cathodes in high brightness electron guns; candidate cathode types; plasma and field emission cathodes; true field emission cathodes; oxide cathodes; lanthanum hexaborides cathodes; laser driven thermionic cathodes; laser driven photocathodes; impregnated porous tungsten dispenser cathodes; and choice of best performing cathode types.

Green, M.C. (Varian Associates, Palo Alto, CA (USA). Palo Alto Microwave Tube Div.)

1987-06-01T23:59:59.000Z

168

Coherence theory of a laser beam passing through a moving diffuser  

Science Journals Connector (OSTI)

Abstract: We present the general coherence theory for laser beams passing through a moving diffuser. The temporal coherence of laser beams passing through a moving diffuser depends on...

Li, Gaoming; Qiu, Yishen; Li, Hui

2013-01-01T23:59:59.000Z

169

E-Print Network 3.0 - augmented laser beam Sample Search Results  

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

Status... -emitting diodes and diode lasers to be built. 13) Design optical beams to achieve specified beam widths, radii... ENG EC570 Lasers and Applications ......

170

Attenuation of laser power of a focused Gaussian beam during interaction between a laser and powder in coaxial laser cladding  

Science Journals Connector (OSTI)

The power of a focused laser beam with a Gaussian intensity profile attenuated by powder in coaxial laser cladding is investigated experimentally and theoretically, and its resolution model is developed. With some assumptions, it is concluded that the attenuation of laser power is an exponential function and is determined by the powder feed rate, particle moving speed, spraying angles and waist positions and diameters of the laser beam and powder flow, grain diameter and run of the laser beam through the powder flow. The attenuation of laser power increases with powder feed rate or run of laser beam through the powder flow. In the experiment presented, 300?W laser power from a focused Gaussian beam is attenuated by a coaxial powder flow. The experimental results agree well with the values calculated with the developed model.

Jichang Liu; Lijun Li; Yuanzhong Zhang; Xiaozhu Xie

2005-01-01T23:59:59.000Z

171

Method for changing the cross section of a laser beam  

DOE Patents (OSTI)

A technique is disclosed herein in which a circular optical beam, for example a copper vapor laser (CVL) beam, is converted to a beam having a profile other than circular, e.g. square or triangular. This is accomplished by utilizing a single optical mirror having a reflecting surface designed in accordance with a specifically derived formula in order to make the necessary transformation, without any substantial light loss and without changing substantially the intensity profile of the circular beam which has a substantially uniform intensity profile. In this way, the output beam can be readily directed into the dye cell of a dye laser. 4 figs.

Sweatt, W.C.; Seppala, L.

1995-12-05T23:59:59.000Z

172

High-repetition Rate Wakefield Electron Source Driven by Few-millijoule Ultrashort Laser Pulses  

Science Journals Connector (OSTI)

10 mJ ultrafast laser pulses acting on gas flow from capillary nozzles generate stable 100 keV electron beams at 500 Hz. Particle-in-cell simulations indicate that slow high amplitude...

He, Zhaohan; Hou, Bixue; Easter, James; Krushelnick, Karl; Nees, John A; Thomas, Alexander

173

Beam physics in future electron hadron colliders  

E-Print Network (OSTI)

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

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

2013-01-01T23:59:59.000Z

174

SPALLATION NEUTRON SOURCE BEAM CURRENT MONITOR ELECTRONICS.  

SciTech Connect

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

KESSELMAN, M.

2001-06-18T23:59:59.000Z

175

Direct atomic flux measurement of electron-beam evaporated yttrium with a diode-laser-based atomic absorption monitor at 668 nm  

E-Print Network (OSTI)

with a diode-laser-based atomic absorption AA monitor at 668 nm. Atomic number density and velocity were measured through absorption and Doppler shift measurements to provide the atomic flux. The AA previously developed diode-laser-based atomic absorption AA monitors for atomic density measurements

Fejer, Martin M.

176

Demodulator electronics for laser vibrometry  

SciTech Connect

One of the most important parts of a fiber-laser vibrometer is demodulation electronic section. The distortion, nonlinearity, offset and added noise of measured signal come from electronic circuits and they have direct influence on finale measuring results. Two main parameters of an investigated vibrating object: velocity V(t) and displacement s(t), influence of detected beat signals. They are: the Doppler frequency deviation f(t) and phase shift {phi}(t), respectively. Because of wide range of deviations it is difficult to use just one demodulator. That is the reason why we use three different types of demodulators. The first one is the IQ demodulator, which is the most sensitive one and its output is proportional to the displacement. Each IQ channel is sampled simultaneously by an analog to digital converter (ADC) integrated in a digital signal processor (DSP). The output signals from the two FM demodulators are proportional to the frequency deviation of heterodyne signals. They are sensitive directly to the velocity of the object. The main disadvantage of scattered light interferometry system is a ''speckle effect'', appearing in relatively large amplitude fluctuation of a heterodyne signal. To minimize ''speckle effect'' influence on quality of beat signals we applied the automatic gain control (AGC) system. Data acquisition, further signal processing (e.g. vibration frequency spectra) and presentation of results is realized by PC via USB interface.

Dudzik, G.; Waz, A. T.; Kaczmarek, P. R.; Antonczak, A. J.; Sotor, J. Z.; Krzempek, K.; Sobon, G.; Abramski, K. M. [Laser and Fibre Electronics Group, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw (Poland)

2012-06-13T23:59:59.000Z

177

Electron beam diagnostic for profiling high power beams  

DOE Patents (OSTI)

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

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

2008-03-25T23:59:59.000Z

178

Attraction and repulsion of multi-color laser beams in plasmas: a computational study  

SciTech Connect

The nonlinear interaction of high-power multi-color laser beams in plasmas is investigated numerically. Both the relativistic mass increase and the driven plasma wave contribute to the mutual beam-beam interaction and to the development of the electromagnetic cascade. The propagation of the individual cascade sidebands is modelled in the paraxial approximation. The resulting set of coupled nonlinear envelope equations is solved numerically using a newly developed pseudospectral method. We predict that two beams intersecting in the plasma can either attract or deflect each other depending on whether their frequency detuning is slightly below or above the electron Langmuir frequency.

Yi, S. A.; Kalmykov, S.; Shvets, G. [Department of Physics and Institute for Fusion Studies, University of Texas at Austin, One University Station C1500, Austin, Texas 78712 (United States)

2009-01-22T23:59:59.000Z

179

Monte Carlo Modeling of Ion Beam Induced Secondary Electrons.  

E-Print Network (OSTI)

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

Huh, Uk

2014-01-01T23:59:59.000Z

180

INEX modeling of the Boeing ring optical resonator free electron laser  

Science Journals Connector (OSTI)

We present new results from the integrated numerical model of the accelerator/beam transport system and ring optical resonator of the Boeing free electron laser experiment. Modifications of the electron-beam transport have been included in a previously developed PARMELA model and are shown to reduce dramatically emittance growth in the 180 bend. The new numerically generated electron beam is used in the 3D FEL simulation code FELEX to calculate expected laser characteristics with the ring optical resonator and the 5 m untapered THUNDER wiggler. Performance sensitivity to optical cavity misalignments is studied.

J.C. Goldstein; R.L. Tokar; B.D. McVey; C.J. Elliott; D.H. Dowell; M.L. Laucks; A.R. Lowrey

1991-01-01T23:59:59.000Z

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


181

Improvement of energy-conversion efficiency from laser to proton beam in a laser-foil interaction  

Science Journals Connector (OSTI)

Improvement of energy-conversion efficiency from laser to proton beam is demonstrated by particle simulations in a laser-foil interaction. When an intense short-pulse laser illuminates the thin-foil target, the foil electrons are accelerated around the target by the ponderomotive force. The hot electrons generate a strong electric field, which accelerates the foil protons, and the proton beam is generated. In this paper a multihole thin-foil target is proposed in order to increase the energy-conversion efficiency from laser to protons. The multiholes transpiercing the foil target help to enhance the laser-proton energy-conversion efficiency significantly. Particle-in-cell 2.5-dimensional (x, y, vx, vy, vz) simulations present that the total laser-proton energy-conversion efficiency becomes 9.3% for the multihole target, though the energy-conversion efficiency is 1.5% for a plain thin-foil target. The maximum proton energy is 10.0MeV for the multihole target and is 3.14MeV for the plain target. The transpiercing multihole target serves as a new method to increase the energy-conversion efficiency from laser to ions.

Y. Nodera; S. Kawata; N. Onuma; J. Limpouch; O. Klimo; T. Kikuchi

2008-10-15T23:59:59.000Z

182

CMOS ROM arrays programmable by laser beam scanning  

E-Print Network (OSTI)

CMOS ROM ARRAYS PROGRAMMABLE BY LASER BEAM SCANNING A Thesis bY JONG JUNE LEE Submitted to the Graduate College of Texas ASM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1984 Major Subject... : Electrical Engineering CMOS ROM ARRAYS PROGRAMMABLE BY LASER BEAM SCANNING A Thesis by JONGJUNE LEE Approved as to style and content by: Noel R. Strader II (Chairman of Committee) Philli E. Allen (Member) Philip S. Noe (Member) Daniel Colunga...

Lee, Jongjune

2012-06-07T23:59:59.000Z

183

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

SciTech Connect

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

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

2013-12-15T23:59:59.000Z

184

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

SciTech Connect

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

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

2006-11-27T23:59:59.000Z

185

Polarized electron beams at milliampere average current  

SciTech Connect

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

Poelker, Matthew [JLAB

2013-11-01T23:59:59.000Z

186

Free-Electron Laser | Jefferson Lab  

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

Research Inspecting an injector assembly at Jefferson Lab's Free-Electron Laser. A D D I T I O N A L L I N K S: FEL Users FEL Description JLAMP Proposal Applications FEL News...

187

Design of titania nanotube structures by focused laser beam direct writing  

SciTech Connect

In this work, we report on electrochemical fabrication of titania films consisting of nanotubes (NTs) and their treatment by focused laser beam. The results of sample characterization by optical and scanning electron microscopy, cathodoluminescence imaging, and Raman scattering scanning spectroscopy are compared to those inherent to specimens subjected to thermal treatment in a furnace. The obtained data demonstrate possibilities for controlling crystallographic structure of TiO{sub 2} NTs by focused laser beam direct writing. These findings open new prospects for the design and fabrication of spatial architectures based on titania nanotubes.

Enachi, Mihai [National Center for Materials Study and Testing, Technical University of Moldova, Stefan cel Mare av. 168, Chisinau, MD-2004 (Moldova, Republic of); Stevens-Kalceff, Marion A. [School of Physics, University of New South Wales, Sydney, New South Wales 2052 (Australia); Sarua, Andrei [H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Ursaki, Veaceslav [Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau, MD-2028 (Moldova, Republic of); Tiginyanu, Ion, E-mail: tiginyanu@asm.md [National Center for Materials Study and Testing, Technical University of Moldova, Stefan cel Mare av. 168, Chisinau, MD-2004 (Moldova, Republic of); Institute of Electronic Engineering and Nanotechnologies, Academy of Sciences of Moldova, Chisinau, MD-2028 (Moldova, Republic of)

2013-12-21T23:59:59.000Z

188

Fast ignition of inertial fusion targets by laser-driven carbon beams  

E-Print Network (OSTI)

Two-dimensional simulations of ion beam driven fast ignition are presented. Ignition energies of protons with Maxwellian spectrum and carbon ions with quasi-monoenergetic and Maxwellian energy distributions are evaluated. The effect of the coronal plasma surrounding the compressed Deuterium-Tritium is studied for three different fuel density distributions. It is found that quasi- monoenergetic ions have better coupling with the compressed Deuterium-Tritium and substantially lower ignition energies. Comparison of quasi-monoenergetic carbon ions and relativistic electrons as ignitor beams shows similar laser energy requirements, provided that a laser to quasi-monoenergetic carbon ion conversion efficiency around 10% can be achieved.

Honrubia, J J; Temporal, M; Hegelich, B M; Meyer-ter-Vehn, J

2009-01-01T23:59:59.000Z

189

Title of Dissertation: CONTROL AND TRANSPORT OF INTENSE ELECTRON BEAMS  

E-Print Network (OSTI)

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

Anlage, Steven

190

Dual beam translator for use in Laser Doppler anemometry  

DOE Patents (OSTI)

A method and apparatus for selectively translating the path of at least one pair of light beams in a Laser Doppler anemometry device whereby the light paths are translated in a direction parallel to the original beam paths so as to enable attainment of spacial coincidence of the two intersection volumes and permit accurate measurements of Reynolds shear stress.

Brudnoy, D.M.

1984-04-12T23:59:59.000Z

191

Susceptor heating device for electron beam brazing  

DOE Patents (OSTI)

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

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

1999-01-01T23:59:59.000Z

192

Electron Beam Ion Source Pre-Injector Diagnostics  

E-Print Network (OSTI)

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

193

Electron beam coupling to a metamaterial structure  

SciTech Connect

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

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

2013-08-15T23:59:59.000Z

194

Drilling Large Diameter Holes in Rocks Using Multiple Laser Beams  

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

Drilling Large Diameter Holes in Rocks Using Multiple Laser Beams (504) Drilling Large Diameter Holes in Rocks Using Multiple Laser Beams (504) Richard Parker,. Parker Geoscience Consulting, LLC, Arvada, Colorado, USA; Zhiyue Xu and Claude Reed, Argonne National Laboratory, Argonne, Illinois, USA; Ramona Graves, Department of Petroleum Engineering, Colorado School of Mines, Golden, Colorado, USA; Brian Gahan and Samih Batarseh, Gas Technology Institute, Des Plaines, Illinois, USA ABSTRACT Studies on drilling petroleum reservoir rocks with lasers show that modern infrared lasers have the capability to spall (thermally fragment), melt and vaporize natural earth materials with the thermal spallation being the most efficient rock removal mechanism. Although laser irradiance as low as 1000 W/cm 2 is sufficient to spall rock, firing the

195

Understanding High-Power Fiber-Optic Laser Beam Delivery  

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

High-Power Fiber-Optic Laser Beam Delivery High-Power Fiber-Optic Laser Beam Delivery The submitted manuscript has been authored by a contractor of the U.S. Government under contract No. W- 31-109-ENG-38. Accordingly, the U.S. Government retains a nonexclusive, royalty-free license to publish or reproduce the published form of this contribution, or allow others to do so, for U.S. Government purposes. Boyd V. Hunter and Keng H. Leong Argonne National Laboratory Technology Development Division Laser Applications Laboratory 9700 South Cass Avenue, Building 207 Argonne, Illinois 60439 Carl B. Miller, James F. Golden, Robert D. Glesias and Patrick J. Laverty U. S. Laser Corporation 825 Windham Court North P. O. Box 609 Wyckoff, New Jersey 07481 March 25, 1996 Manuscript to be submitted to Journal of Laser Applications

196

Electrostatic electron cyclotron waves generated by low-energy electron beams  

E-Print Network (OSTI)

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

Santolik, Ondrej

197

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

Science Journals Connector (OSTI)

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

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

2009-06-01T23:59:59.000Z

198

A multi-beam, multi-terawatt Ti:sapphire laser system for laser wake-field acceleration studies  

E-Print Network (OSTI)

­plasma interaction studies, such as development of laser wake-field accelerators [1-4], X-ray lasers, and laserA multi-beam, multi-terawatt Ti:sapphire laser system for laser wake-field acceleration studies 71R0259, 1 Cyclotron Rd., Berkeley, CA 94720, USA, e-mail: ctoth@lbl.gov Abstract. The Lasers

Geddes, Cameron Guy Robinson

199

Analysis of saturation phenomena in Cerenkov free-electron lasers with a planar waveguide  

SciTech Connect

In this paper, the operation of the stimulated emission in Cerenkov free-electron laser (CFEL) is studied on the basis of the modulations of electron velocity and density by the electromagnetic (EM) field. The influence of the electron relaxation, due to mutual electrons collisions, on the electron dynamics is taken into account. We investigate the growth characteristics of Cerenkov laser operating in the small-signal and saturation regimes. In the saturation regime, the effect of velocity reduction of the electron beam on the gain dynamics is demonstrated. We also show that our results match with those of other well-known treatments in the small-signal gain limit.

Fares, Hesham; Yamada, Minoru [Division of Electrical Engineering and Computer Science, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192 (Japan)

2011-09-15T23:59:59.000Z

200

Axial interaction free-electron laser  

DOE Patents (OSTI)

Electron orbits from a helical axial wiggler in an axial guide field are absolutely unstable as power is extracted from the particles. For off-axis beams an axial FEL mechanism exists when the axial electric field in a TM mode is wiggled to interact with the axial velocity of the electrons that form the beam. The interaction strength is comparable to that for helical FELs and is insensitive to beam orbit errors. The orbits for this mechanism are extremely stable in the absence of space charge and lead to high extraction efficiencies without particle phasing incoherence or interception. This interaction mechanism is suitable for use with intense annular electron beams for high power generation at microwave frequencies. 5 figs.

Carlsten, B.E.

1997-09-02T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

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

202

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

E-Print Network (OSTI)

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

203

Initial source of microbunching instability studies in a free electron laser injector  

SciTech Connect

We present the first experimental studies of the initial source of electron beam microbunching instability in a free electron laser (FEL) injector. By utilizing for the studies a transform-limited laser pulse at the photocathode, we eliminated laser-induced microbunching at the National Synchrotron Light Source Source Development Laboratory (SDL). The detailed measurements of the resulting electron beam led us to conclude that, at SDL, microbunching arising from shot noise is not amplified to any significant level, thereby allowing us to set an upper limit on the initial modulation depth of microbunching arising from shot noise. Our analysis demonstrated that the only significant source of microbunching instability under normal operational conditions at SDL is the longitudinal modulation of the photocathode laser pulse. Our work shows that assuring a longitudinally smoothed photocathode laser pulse allows mitigating microbunching instability at a typical FEL injector with a moderate microbunching gain.

Seletskiy, S.; Hidaka, Y; Murphy, J.B.; Podobedov, B.; Qian, H.; Shen, Y.; Wang, X.J.; Yang, X

2011-11-16T23:59:59.000Z

204

X-Ray Radiation from Nonlinear Thomson Scattering of an Intense Femtosecond Laser on Relativistic Electrons in a Helium Plasma  

E-Print Network (OSTI)

X-Ray Radiation from Nonlinear Thomson Scattering of an Intense Femtosecond Laser on Relativistic laser beam on plasma electrons. A collimated x-ray radiation with a broad continuous spectrum peaked by the ultraintense laser fields. The results show the existence of several physical mecha- nisms for the x-ray

Umstadter, Donald

205

Polarized electron beams at milliampere average current  

SciTech Connect

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

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

2013-11-07T23:59:59.000Z

206

LASER APPLICATIONS: H- BEAM PHOTO-DETACHMENT AND PUSH BUTTON DIAGNOSTICS  

SciTech Connect

The laser based nonintrusive H- beam diagnostics and laser assisted H- beam stripping technologies have been developed at the Spallation Neutron Source (SNS). This paper reviews the present status of the SNS laser based diagnostics and the recent R&D progress on the fiber transmission of laser pulses and power enhancement optical cavity which will be used in diagnostics and laser stripping.

Liu, Yun [ORNL

2012-01-01T23:59:59.000Z

207

Dispersion relation and growth rate in a Cherenkov free electron laser: Finite axial magnetic field  

SciTech Connect

A theoretical analysis is presented for dispersion relation and growth rate in a Cherenkov free electron laser with finite axial magnetic field. It is shown that the growth rate and the resonance frequency of Cherenkov free electron laser increase with increasing axial magnetic field for low axial magnetic fields, while for high axial magnetic fields, they go to a saturation value. The growth rate and resonance frequency saturation values are exactly the same as those for infinite axial magnetic field approximation. The effects of electron beam self-fields on growth rate are investigated, and it is shown that the growth rate decreases in the presence of self-fields. It is found that there is an optimum value for electron beam density and Lorentz relativistic factor at which the maximum growth rate can take place. Also, the effects of velocity spread of electron beam are studied and it is found that the growth rate decreases due to the electron velocity spread.

Kheiri, Golshad; Esmaeilzadeh, Mahdi [Department of Physics, Iran University of Science and Technology, Tehran 16844 (Iran, Islamic Republic of)] [Department of Physics, Iran University of Science and Technology, Tehran 16844 (Iran, Islamic Republic of)

2013-12-15T23:59:59.000Z

208

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

SciTech Connect

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

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

2012-12-21T23:59:59.000Z

209

Two-Beam Instability in Electron Cooling  

SciTech Connect

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

Burov, Alexey V.; /Fermilab

2006-04-01T23:59:59.000Z

210

Nonlinear transmission line based electron beam driver  

SciTech Connect

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

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

2012-12-15T23:59:59.000Z

211

Waveguide submillimetre laser with a uniform output beam  

SciTech Connect

A method for producing non-Gaussian light beams with a uniform intensity profile is described. The method is based on the use of a combined waveguide quasi-optical resonator containing a generalised confocal resonator with an inhomogeneous mirror with absorbing inhomogeneities discretely located on its surface and a hollow dielectric waveguide whose size satisfies the conditions of self-imaging of a uniform field in it. The existence of quasi-homogeneous beams at the output of an optically pumped 0.1188-mm waveguide CH{sub 3}OH laser with a amplitude-stepped mirror is confirmed theoretically and experimentally. (lasers)

Volodenko, A V; Gurin, O V; Degtyarev, A V; Maslov, Vyacheslav A; Svich, V A; Topkov, A N [V.N. Karazin Kharkiv National University, Kharkiv (Ukraine)

2007-01-31T23:59:59.000Z

212

Progress toward the Wisconsin Free Electron Laser  

SciTech Connect

The University of Wisconsin-Madison/Synchrotron Radiation Center is advancing its design for a seeded VUV/soft X-ray Free Electron Laser facility called WiFEL. To support this vision of an ultimate light source, we are pursuing a program of strategic R&D addressing several crucial elements. This includes development of a high repetition rate, VHF superconducting RF electron gun, R&D on photocathode materials by ARPES studies, and evaluation of FEL facility architectures (e.g., recirculation, compressor scenarios, CSR dechirping, undulator technologies) with the specific goal of cost containment. Studies of high harmonic generation for laser seeding are also planned.

Bisognano, Joseph; Eisert, D; Fisher, M V; Green, M A; Jacobs, K; Kleman, K J; Kulpin, J; Rogers, G C; Lawler, J E; Yavuz, D

2011-03-01T23:59:59.000Z

213

Laser-Plasma Acceleration of Electrons and Plasma Diagnostics at High Laser Fields  

E-Print Network (OSTI)

would open the prospect of building x-ray free-electron lasers and linear colliders hundreds of timesLaser-Plasma Acceleration of Electrons and Plasma Diagnostics at High Laser Fields Mike Downer: Laser-plasma acceleration is now entering an era of petawatt lasers, tenuous plasmas and multi

Shvets, Gennady

214

Development of a fast position-sensitive laser beam detector  

SciTech Connect

We report the development of a fast position-sensitive laser beam detector. The detector uses a fiber-optic bundle that spatially splits the incident beam, followed by a fast balanced photodetector. The detector is applied to the study of Brownian motion of particles on fast time scales with 1 A spatial resolution. Future applications include the study of molecule motors, protein folding, as well as cellular processes.

Chavez, Isaac; Huang Rongxin; Henderson, Kevin; Florin, Ernst-Ludwig; Raizen, Mark G. [Center for Nonlinear Dynamics and Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States)

2008-10-15T23:59:59.000Z

215

Electron beam diagnostic for space charge measurement of an ion beam  

SciTech Connect

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

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

2004-09-25T23:59:59.000Z

216

High energy heavy ion jets emerging from laser plasma generated by long pulse laser beams from  

E-Print Network (OSTI)

, Albuquerque, New Mexico. ~Received 21 February 2005; Accepted 20 April 2005! Abstract High energy heavy ions to the fast ion emission process. The interest in laser plasmas and interaction phenomena of heavy ion beams!. Thus there is a tradition to investigate accelerator related issues like beam transport phenomena

217

Possible generation of $?$-ray laser by electrons wiggling in a background laser  

E-Print Network (OSTI)

The possibility of $\\gamma-$ray laser generation by the radiation of wiggling electrons in an usual background laser is discussed.

Qi-Ren Zhang

2014-08-13T23:59:59.000Z

218

Electron Beam Emission Characteristics from Plasma Focus Devices  

Science Journals Connector (OSTI)

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

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

2006-01-01T23:59:59.000Z

219

Novel Vortex Generator and Mode Converter for Electron Beams  

Science Journals Connector (OSTI)

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

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

2012-08-22T23:59:59.000Z

220

Electron beam diagnostic system using computed tomography and an annular sensor  

DOE Patents (OSTI)

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

Elmer, John W.; Teruya, Alan T.

2014-07-29T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

Multigigahertz beam diagnostics for laser fusion  

SciTech Connect

A system to make ultra wideband measurements of fast laser pulses and their induced target interactions at a distance of approximately 38 m from the target location is discussed. The system has demonstrated an overall bandwidth of 3 GHz with projected unfolding to 4 GHz. This system allows high resolution temporal history diagnostics in a remote location providing high EMI and radiation immunity.

Smith, R.C.; Hodson, E.K.; Carlson, R.L.

1981-01-01T23:59:59.000Z

222

Laser beam control and diagnostic systems for the copper-pumped dye laser system at Lawrence Livermore National Laboratory  

SciTech Connect

The laser system described in the previous paper is used for experiments in which success requires tight tolerances on beam position, direction, and wavefront. Indeed, the optimum performance of the laser itself depends on careful delivery of copper laser light to the dye amplifiers, precise propagation of dye laser beams through restricted amplifier apertures, and accurate monitoring of laser power at key locations. This paper describes the alignment systems, wavefront correction systems, and laser diagnostics systems which ensure that the control requirements of both the laser and associated experiments are met. Because laser isotope separation processes utilize more than one wavelength, these systems monitor and control multiple wavelengths simultaneously.

Bliss, E.S.; Peterson, R.L.; Salmon, J.T.; Thomas, R.A.

1992-11-01T23:59:59.000Z

223

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

E-Print Network (OSTI)

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams C. B. Schroeder, E of an intense laser or the space-charge force of a charged particle beam. The implications for accelerator design and the different physical mechanisms of laser-driven and beam-driven plasma acceleration

Geddes, Cameron Guy Robinson

224

Electron-beam-driven nanoscale metamaterial light sources  

Science Journals Connector (OSTI)

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

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

225

A compact x-ray free electron laser  

SciTech Connect

We present a design concept and simulation of the performance of a compact x-ray, free electron laser driven by ultra-high gradient rf-linacs. The accelerator design is based on recent advances in high gradient technology by a LLNL/SLAC/LBL collaboration and on the development of bright, high current electron sources by BNL and LANL. The GeV electron beams generated with such accelerators can be converted to soft x-rays in the range from 2--10 nm by passage through short period, high field strength wigglers as are being designed at Rocketdyne Linear light sources of this type can produce trains of picosecond (or shorter) pulses of extremely high spectral brilliance suitablee for flash holography of biological specimens in vivo and for studies of fast chemical reactions. 12 refs., 8 figs., 4 tabs.

Barletta, W.A. (California Univ., Los Angeles, CA (USA). Center for Advanced Accelerators Physics Lawrence Livermore National Lab., CA (USA)); Atac, M.; Cline, D.B.; Kolonko, J. (California Univ., Los Angeles, CA (USA). Center for Advanced Accelerators Physics); Bhowmik, A.; Bobbs, B.; Cover, R.A.; Dixon, F.P.; Rakowsky, G. (Rockwell International Corp., Canoga Park, CA (USA). Rocketdyne Div.); Gallardo

1988-01-01T23:59:59.000Z

226

A compact x-ray free electron laser  

SciTech Connect

We present a design concept and simulation of the performance of a compact x-ray, free electron laser driven by ultra-high gradient rf-linacs. The accelerator design is based on recent advances in high gradient technology by a LLNL/SLAC/LBL collaboration and on the development of bright, high current electron sources by BNL and LANL. The GeV electron beams generated with such accelerators can be concerted to soft x-rays in the range from 2--10 nm by passage through short period, high fields strength wigglers as are being designed at Rocketdyne. Linear light sources of this type can produce trains of picosecond (or shorter) pulses of extremely high spectral brilliance suitable for flash holography of biological specimens in vivo and for studies of fast chemical reactions. 12 refs., 8 figs., 4 tabs.

Barletta, W.; Attac, M.; Cline, D.B.; Kolonko, J.; Wang, X.; Bhowmik, A.; Bobbs, B.; Cover, R.A.; Dixon, F.P.; Rakowsky, G.; Gallardo, J.; Pellegrini, C.; Westenskow, G.

1988-09-09T23:59:59.000Z

227

Terahertz generation by two cross focused laser beams in collisional plasmas  

SciTech Connect

The role of two cross-focused spatial-Gaussian laser beams has been studied for the high power and efficient terahertz (THz) radiation generation in the collisional plasma. The nonlinear current at THz frequency arises on account of temperature dependent collision frequency of electrons with ions in the plasma and the presence of a static electric field (applied externally in the plasma) and density ripple. Optimisation of laser-plasma parameters gives the radiated THz power of the order of 0.23??MW.

Sharma, R. P., E-mail: rpsharma@ces.iitd.ernet.in; Singh, Ram Kishor, E-mail: ram007kishor@gmail.com [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110016 (India)

2014-07-15T23:59:59.000Z

228

Laser beam apparatus and method for analyzing solar cells  

DOE Patents (OSTI)

A laser beam apparatus and method for analyzing, inter alia, the current versus voltage curve at the point of illumination on a solar cell and the open circuit voltage of a solar cell. The apparatus incorporates a lock-in amplifier, and a laser beam light chopper which permits the measurement of the AC current of the solar cell at an applied DC voltage at the position on the solar cell where the cell is illuminated and a feedback scheme which permits the direct scanning measurements of the open circuit voltage. The accuracy of the measurement is a function of the intensity and wavelength of the laser light with respect to the intensity and wavelength distribution of sunlight and the percentage the dark current is at the open circuit voltage to the short circuit current of the solar cell.

Staebler, David L. (Lawrenceville, NJ)

1980-01-01T23:59:59.000Z

229

Preparation of random phase plates for laser beam smoothing  

SciTech Connect

Phase plates are required for removing aberrations from laser beams caused by inhomogeneities in the optical components of the laser. The first type of plate that we prepared consisted of a bi-level optical component that caused spatial smoothing of the beam by breaking it up into a fine scale spatial structure. This was made by etching a pattern directly into the substrate using HF/NH{sub 4}F. Components up to 80 cm in diameter were prepared but these are only 85% efficient because of beam losses in secondary maxima. Multilevel designs are more efficient and we have prepared 5 inch diameter samples with 16 levels. These require four separate etch steps but have efficiencies greater than 90%.

Thomas, I.M.; Dixit, S.N.; Rushford, M.C.

1994-11-21T23:59:59.000Z

230

Preparation of random phase plates for laser beam smoothing  

SciTech Connect

Phase plates are required to remove aberrations from laser beams caused by inhomogeneities in the optical components of the laser. The first type of plate that we prepared consisted of a bi-level optical component that caused spatial smoothing of the beam by breaking it up into a fine scale spatial structure. This was made by etching a pattern directly into the substrate using HF/NH{sub 4}F. Components up to 80 cm in diameter were prepared but these are only 85% efficient because of beam losses in secondary maxima. Multilevel designs are more efficient and we have prepared 5 inch diameter samples with 16 levels. These require four separate etch steps but have efficiencies greater than 90%.

Thomas, I.M.; Dixit, S.N.; Rushford, M.C. [Lawrence Livermore National Lab., CA (United States)

1995-12-31T23:59:59.000Z

231

Laser Irradiated Enhancement of the Atomic Electron Capture Rate in search of New Physics  

E-Print Network (OSTI)

Electron capture processes are important in the search for new physics. In this context, a high capture rate is desired. We investigate the possibility of enhancing the electron capture rate by irradiating laser beam to ''atom''. The possibility of such enhancement can be understood as a consequence of an enhancement of the electron wave function at the origin, $\\Psi (0)$, through an increased effective mass of the electron. We find that an order of magnitude enhancement can be realized by using a laser with intensity on the order of $10^{10}$ W/mm$^2$ and a photon energy on the order of $10^{-3}$ eV.

Takaaki Nomura; Joe Sato; Takashi Shimomura

2007-06-16T23:59:59.000Z

232

The splitted laser beam filamentation in interaction of laser and an exponential decay inhomogeneous underdense plasma  

SciTech Connect

The splitted beam filamentation in interaction of laser and an exponential decay inhomogeneous underdense plasma is investigated. Based on Wentzel-Kramers-Brillouin (WKB) approximation and paraxial/nonparaxial ray theory, simulation results show that the steady beam width and single beam filamentation along the propagation distance in paraxial case is due to the influence of ponderomotive nonlinearity. In nonparaxial case, the influence of the off-axial of {alpha}{sub 00} and {alpha}{sub 02} (the departure of the beam from the Gaussian nature) and S{sub 02} (the departure from the spherical nature) results in more complicated ponderomotive nonlinearity and changing of the channel density and refractive index, which led to the formation of two/three splitted beam filamentation and the self-distortion of beam width. In addition, influence of several parameters on two/three splitted beam filamentation is discussed.

Xia Xiongping; Yi Lin [Department of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Xu Bin [Department of Mathematics and Information Sciences, North China Institute of Water Conservancy and Hydroelectric Power, Zhengzhou 450011 (China); Lu Jianduo [Department of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Hubei Province Key Laboratory of Systems Science in Metallurgical Process, Wuhan University of Science and Technology, Wuhan 430081 (China)

2011-10-15T23:59:59.000Z

233

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

E-Print Network (OSTI)

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

Schroeder, C. B.

2011-01-01T23:59:59.000Z

234

INEX (integrated numerical experiment) simulations of the Los Alamos HIBAF (high-brightness accelerator free-electron laser) free-electron laser MOPA (master oscillator power amplifier) experiment  

SciTech Connect

We present results of Integrated Numerical Experiment (INEX) simulations of the performance of a 1-m untapered wiggler FEL oscillator driving a 2-m wiggler FEL amplifier for the new HIBAF (High-Brightness Accelerator Free-Electron Laser) facility at Los Alamos. INEX simulations utilize a numerically-generated electron micropulse, from ISIS/PARMELA calculations of the photoinjector/linac/beam transport system, in the 3-D FEL simulation code FELEX. 13 refs., 10 figs., 1 tab.

Goldstein, J.C.; Carlsten, B.E.; McVey, B.D.

1989-01-01T23:59:59.000Z

235

Quantum effects in electron beam pumped GaAs  

SciTech Connect

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

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

2013-08-19T23:59:59.000Z

236

Beam Imaging of a High-Brightness Elliptic Electron Gun  

SciTech Connect

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

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

2010-11-04T23:59:59.000Z

237

HIGH ENERGY ELECTRON BEAM (HEEB) PROCESSING OF ADVANCED MATERIALS  

E-Print Network (OSTI)

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

Eagar, Thomas W.

238

Project Execution Plan Electron Beam Ion Source Project  

E-Print Network (OSTI)

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

239

Electron Gun For Multiple Beam Klystron Using Magnetic Focusing  

DOE Patents (OSTI)

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

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

2004-07-27T23:59:59.000Z

240

Laser beam self-focusing in the atmosphere  

SciTech Connect

We propose to exploit a self-focusing effect in the atmosphere to assist delivering powerful laser beams from orbit to the ground. We demonstrate through numerical modeling that if the self-focusing length is comparable with the atmosphere height the self-focusing can reduce the spot size on the ground well below the diffraction limited one without beam quality degradation. The use of light self-focusing in the atmosphere can greatly relax the requirements for the orbital optics and ground receivers.

Rubenchik, A M; Fedoruk, M P; Turitsyn, S K

2008-09-09T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

XUV free-electron laser-based projection lithography systems  

SciTech Connect

Free-electron laser sources, driven by rf-linear accelerators, have the potential to operate in the extreme ultraviolet (XUV) spectral range with more than sufficient average power for high-volume projection lithography. For XUV wavelengths from 100 nm to 4 nm, such sources will enable the resolution limit of optical projection lithography to be extended from 0.25 {mu}m to 0.05{mu}m and with an adequate total depth of focus (1 to 2 {mu}m). Recent developments of a photoinjector of very bright electron beams, high-precision magnetic undulators, and ring-resonator cavities raise our confidence that FEL operation below 100 nm is ready for prototype demonstration. We address the motivation for an XUV FEL source for commercial microcircuit production and its integration into a lithographic system, include reflecting reduction masks, reflecting XUV projection optics and alignment systems, and surface-imaging photoresists. 52 refs., 7 figs.

Newnam, B.E.

1990-01-01T23:59:59.000Z

242

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

E-Print Network (OSTI)

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

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

2014-01-01T23:59:59.000Z

243

Acceleration of electrons using an inverse free electron laser auto- accelerator  

SciTech Connect

We present data from our study of a device known as the inverse free electron laser. First, numerical simulations were performed to optimize the design parameters for an experiment that accelerates electrons in the presence of an undulator by stimulated absorption of radiation. The Columbia free electron laser (FEL) was configured as an auto-accelerator (IFELA) system; high power (MW's) FEL radiation at {approximately}1.65 mm is developed along the first section of an undulator inside a quasi-optical resonator. The electron beam then traverses a second section of undulator where a fraction of the electrons is accelerated by stimulated absorption of the 1.65 mm wavelength power developed in the first undulator section. The second undulator section has very low gain and does not generate power on its own. We have found that as much as 60% of the power generated in the first section can be absorbed in the second section, providing that the initial electron energy is chosen correctly with respect to the parameters chosen for the first and second undulators. An electron momentum spectrometer is used to monitor the distribution of electron energies as the electrons exit the IFELA. We have found; using our experimental parameters, that roughly 10% of the electrons are accelerated to energies as high as 1100 keV, in accordance with predictions from the numerical model. The appearance of high energy electrons is correlated with the abrupt absorption of millimeter power. The autoaccelerator configuration is used because there is no intense source of coherent power at the 1.65 mm design wavelength other than the FEL.

Wernick, I.K.; Marshall, T.C.

1992-07-01T23:59:59.000Z

244

Acceleration of electrons using an inverse free electron laser auto- accelerator  

SciTech Connect

We present data from our study of a device known as the inverse free electron laser. First, numerical simulations were performed to optimize the design parameters for an experiment that accelerates electrons in the presence of an undulator by stimulated absorption of radiation. The Columbia free electron laser (FEL) was configured as an auto-accelerator (IFELA) system; high power (MW`s) FEL radiation at {approximately}1.65 mm is developed along the first section of an undulator inside a quasi-optical resonator. The electron beam then traverses a second section of undulator where a fraction of the electrons is accelerated by stimulated absorption of the 1.65 mm wavelength power developed in the first undulator section. The second undulator section has very low gain and does not generate power on its own. We have found that as much as 60% of the power generated in the first section can be absorbed in the second section, providing that the initial electron energy is chosen correctly with respect to the parameters chosen for the first and second undulators. An electron momentum spectrometer is used to monitor the distribution of electron energies as the electrons exit the IFELA. We have found; using our experimental parameters, that roughly 10% of the electrons are accelerated to energies as high as 1100 keV, in accordance with predictions from the numerical model. The appearance of high energy electrons is correlated with the abrupt absorption of millimeter power. The autoaccelerator configuration is used because there is no intense source of coherent power at the 1.65 mm design wavelength other than the FEL.

Wernick, I.K.; Marshall, T.C.

1992-07-01T23:59:59.000Z

245

Laser induced electron acceleration in vacuum K. P. Singha)  

E-Print Network (OSTI)

Laser induced electron acceleration in vacuum K. P. Singha) Department of Physics, Indian Institute acceleration by a plane polarized laser wave has been studied in vacuum. Relativistic equations of motion have been solved exactly for electron trajectory and energy as a function of laser intensity, phase

Singh, Kunwar Pal

246

Radiation reaction in ultrarelativistic laserspinning electron interactions  

Science Journals Connector (OSTI)

......electron behaves something like resistance in this ultrarelativistic laser-electron...Here, it is assumed that the electric and magnetic dipoles are linearly...experimental fact, we assume that the electric dipole of an elementary particle (an electron) does......

Keita Seto; Hideo Nagatomo; James Koga; Kunioki Mima

2013-05-01T23:59:59.000Z

247

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?

248

Second harmonic generation by propagation of a p-polarized obliquely incident laser beam in underdense plasma  

SciTech Connect

An analytical study of second harmonic generation due to interaction an intense, p-polarized laser beam propagating obliquely in homogeneous underdense plasma, in the mildly relativistic regime, has been presented. The efficiency of the second harmonic radiation as well as its detuning length has been obtained and their variation with the angle of incidence is analyzed. It is shown that, for a given plasma electron density, the second harmonic efficiency increases with the angle of incidence while the detuning length decreases. The second harmonic amplitude vanishes at normal incidence of the laser beam.

Jha, Pallavi; Agrawal, Ekta [Department of Physics, University of Lucknow, Lucknow-226007 (India)

2014-05-15T23:59:59.000Z

249

Applications of power beaming from space-based nuclear power stations. [Laser beaming to airplanes; microwave beaming to ground  

SciTech Connect

Power beaming from space-based reactor systems is examined using an advanced compact, lightweight Rotating Bed Reactor (RBR). Closed Brayton power conversion efficiencies in the range of 30 to 40% can be achieved with turbines, with reactor exit temperatures on the order of 2000/sup 0/K and a liquid drop radiator to reject heat at temperatures of approx. 500/sup 0/K. Higher RBR coolant temperatures (up to approx. 3000/sup 0/K) are possible, but gains in power conversion efficiency are minimal, due to lower expander efficiency (e.g., a MHD generator). Two power beaming applications are examined - laser beaming to airplanes and microwave beaming to fixed ground receivers. Use of the RBR greatly reduces system weight and cost, as compared to solar power sources. Payback times are a few years at present prices for power and airplane fuel.

Powell, J.R.; Botts, T.E.; Hertzberg, A.

1981-01-01T23:59:59.000Z

250

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

251

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

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

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

252

A Programmable Beam Shaping System for Tailoring the Profile of High Fluence Laser Beams  

SciTech Connect

Customized spatial light modulators have been designed and fabricated for use as precision beam shaping devices in fusion class laser systems. By inserting this device in a low-fluence relay plane upstream of the amplifier chain, 'blocker' obscurations can be programmed into the beam profile to shadow small isolated flaws on downstream optical components that might otherwise limit the system operating energy. In this two stage system, 1920 x 1080 bitmap images are first imprinted on incoherent, 470 nm address beams via pixilated liquid crystal on silicon (LCoS) modulators. To realize defined masking functions with smooth apodized shapes and no pixelization artifacts, address beam images are projected onto custom fabricated optically-addressable light valves. Each valve consists of a large, single pixel liquid cell in series with a photoconductive Bismuth silicon Oxide (BSO) crystal. The BSO crystal enables bright and dark regions of the address image to locally control the voltage supplied to the liquid crystal layer which in turn modulates the amplitude of the coherent beams at 1053 nm. Valves as large as 24 mm x 36 mm have been fabricated with low wavefront distortion (<0.5 waves) and antireflection coatings for high transmission (>90%) and etalon suppression to avoid spectral and temporal ripple. This device in combination with a flaw inspection system and optic registration strategy represents a new approach for extending the operational lifetime of high fluence laser optics.

Heebner, J; Borden, M; Miller, P; Stolz, C; Suratwala, T; Wegner, P; Hermann, M; Henesian, M; Haynam, C; Hunter, S; Christensen, K; Wong, N; Seppala, L; Brunton, G; Tse, E; Awwal, A; Franks, M; Marley, E; Williams, K; Scanlan, M; Budge, T; Monticelli, M; Walmer, D; Dixit, S; Widmayer, C; Wolfe, J; Bude, J; McCarty, K; DiNicola, J

2010-11-10T23:59:59.000Z

253

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

DOE Patents (OSTI)

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

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

2013-10-01T23:59:59.000Z

254

fel 2005 :: Free Electron Laser Conference and Workshop  

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

Home | Attendee List | Program | Abstract Submission | Payment | Call for Papers | Exhibitors | Travel 2005 International Free Electron Laser Prize Winner: Avi Gover left to right: John Galayda, Avi Gover (FEL2005 Prize Winner, Alexander Van der Meer This year the FEL Prize Committee awarded the FEL Prize to Avraham (Avi) Gover from Tel-Aviv University for his pioneering work in laying the foundation of FEL theory. Avi Gover, presently head of the FEL Knowledge Center in Israel, has been a member of the FEL community from the very beginning, publishing his first paper on FELs in 1976. In those early years, he played a key role in putting FEL theory on a firm basis by showing the similarities between FELs, 'ordinary' lasers and other free electron radiation devices such as TWTs. In later years he made important contributions to the formulation of a unified theory of superradiant emission in the linear and, more recently, also in the non-linear regime. His deep understanding of the field enabled him to propose conceptually new schemes like stimulated superradiance and post-saturation emission enhancement. In addition to his extensive work and contributions to FEL theory, he also led and contributed to a number of experimental projects aimed at studies of fundamental effects and at the development of new FEL device schemes. Most notably the demonstration of a two-stage BWO FEL and a longitudinal wiggler FEL, demonstration of electron trapping in two counter propagating laser beams and of single-mode locking in a prebunched FEM. He has also been the main driving force behind the international efforts to develop high-average power masers based on electrostatic accelerators in the inverted setup, that is with the undulator at high voltage. Along this line, he also took the initiative for an Israelean FEM user facility and notwithstanding the difficult funding situation in his country, this facility is now operational at the College of Judea and Samaria in Ariel.

255

Plasma Heating by High-Current Relativistic Electron Beams  

Science Journals Connector (OSTI)

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

R. V. Lovelace and R. N. Sudan

1971-11-08T23:59:59.000Z

256

Observation of gain in a free-electron laser master oscillator-power amplifier  

SciTech Connect

We report the first operation of a master oscillator-power amplifier in which both devices are free-electron lasers. Gain optimization in the power amplifier was studied. A 35-A electron beam produced up to 60% gain at 3 {mu}m. The gain spectrum was obtained by gap tuning the power amplifier wiggler and evidence was found for violation of the Madey theorem due to high gain effects.

Vintro, L.; Benson, S.V.; Bhowmik, A.; Curtin, M.S.; Madey, J.M.J.; McMullin, W.A.; Richman, R.A. (Stanford Photon Research Laboratory, Stanford University, Stanford, California 94305 (USA) Rocketdyne Division, Rockwell International, 6633 Canoga Avenue, Canoga Park, California 91303 (USA))

1990-04-02T23:59:59.000Z

257

Lateral propagation of MeV electrons generated by femtosecond laser irradiation  

SciTech Connect

The propagation of MeV electrons generated by intense (approx =10{sup 20} W/cm{sup 2}) femtosecond laser irradiation, in the lateral direction perpendicular to the incident laser beam, was studied using targets consisting of irradiated metal wires and neighboring spectator wires embedded in electrically conductive (aluminum) or resistive (Teflon) substrates. The K shell spectra in the energy range 40-60 keV from wires of Gd, Dy, Hf, and W were recorded by a transmission crystal spectrometer. The spectra were produced by 1s electron ionization in the irradiated wire and by energetic electron propagation through the substrate material to the spectator wire of a different metal. The electron range and energy were determined from the relative K shell emissions from the irradiated and spectator wires separated by varying substrate lateral distances of up to 1 mm. It was found that electron propagation through Teflon was inhibited, compared to aluminum, implying a relatively weak return current and incomplete space-charge neutralization. The energetic electron propagation in the direction parallel to the electric field of the laser beam was larger than perpendicular to the electric field. Energetic electron production was lower when directly irradiating aluminum or Teflon compared to irradiating the heavy metal wires. These experiments are important for the determination of the energetic electron production mechanism and for understanding lateral electron propagation that can be detrimental to fast-ignition fusion and hard x-ray backlighter radiography.

Seely, J. F. [Space Science Division, Naval Research Laboratory, Washington DC 20375 (United States); Szabo, C. I. [Laboratoire Kastler Brossel, Ecole Normale Superieure, CNRS, Universite P. et M. Curie-Paris 6 Case 74, 4, Place Jussieu, 75252 Paris Cedex 05 (France); Audebert, P.; Brambrink, E.; Tabakhoff, E. [Laboratoire pour L'Utilisation des Lasers Intenses (LULI), Ecole Polytechnique, 91128 Palaiseau Cedex (France); Hudson, L. T. [National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

2010-02-15T23:59:59.000Z

258

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

259

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

260

Electron-beam-induced absorption in quartz glasses  

Science Journals Connector (OSTI)

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

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

2004-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

Relativistic electron beams detection in a dense plasma focus  

Science Journals Connector (OSTI)

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

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

2002-10-01T23:59:59.000Z

262

Jefferson Lab electron beam charges up | Jefferson Lab  

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

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

263

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

E-Print Network (OSTI)

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

Kaganovich, Igor

264

A Gridded Electron Gun for a Sheet Beam Klystron  

SciTech Connect

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

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

2008-04-25T23:59:59.000Z

265

Laser Electron Gamma Source: Biennial progress report, June 1996  

SciTech Connect

The LEGS facility provides intense, polarized, monochromatic {gamma}-ray beams by Compton backscattering laser light from relativistic electrons circulating in the X-Ray storage ring of the National Synchrotron Light Source at Brookhaven national Laboratory. Since 1990, experiments have concentrated on single polarization observables (polarized beams on unpolarized targets) in nuclear reactions involving the {Delta} resonance. Highlights of the last two years are given. An updated status of LEGS, and recent publications, is available on the WWW via http://WWW.LEGS.BNL.GOV/{approximately}LEGS/. In 1997 a new phase of operations will begin, focusing on double-polarization measurements with circularly polarized photon beams and longitudinally polarized nucleon targets. This work requires the development of (i) a new frozen-spin hydrogen-deuteride target that provides high polarizations for both nuclear species, and (ii) a new large acceptance detector array for measuring total reaction cross sections in both neutral and charged-particle channels. Progress on these instrumentation developments is an ongoing effort of the LEGS Spin Collaboration (LSC) and is discussed in the last section of this report.

Sandorfi, A.M. [ed.

1996-09-01T23:59:59.000Z

266

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

E-Print Network (OSTI)

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

California at Berkeley, University of

267

Jefferson Lab's upgraded Free-Electron Laser produces first ligh...  

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

upgraded Free-Electron Laser produces first light June 18, 2003 Researchers at the U.S. Department of Energy's Thomas Jefferson National Accelerator Facility have produced first...

268

Free-Electron Lasers: Present Status and Future Prospects  

E-Print Network (OSTI)

US Department of Energy under contract DE-AC03-76SF00098. LBL-29124 Free-Electron Lasers: Present Status

Kim, K.-J.

2008-01-01T23:59:59.000Z

269

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

Science Journals Connector (OSTI)

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

Govindan Rangarajan and K. C. D. Chan

1989-05-01T23:59:59.000Z

270

A polarized look at nucleons: Laser electron gamma source  

SciTech Connect

As the title suggests we are going to look at reactions induced on nucleons by polarized photons. The results I am going to show today are from the Laser Electron Gamma Source, or LEGS'' facility, at Brookhaven National Laboratory. At LEGS, gamma ray beams are produced by backscattering laser light from relativistic electrons. I will only summarize the main characteristics of this facility, and leave an in depth description to Dr. Schaerf who will discuss LEGS and other similar backscattering facilities on Wednesday. Reactions with polarized photons inevitably reflect interference terms that for the most part remain hidden in spin-averaged unpolarized measurements. This provides a tool for probing interactions that depend upon spin. In particular, we are going to look today at two cases where the polarization is used to probe the tensor interaction. First, we will examine the tensor force between a proton-neutron pair in deuterium. Secondly, we will examine the tensor force between quarks in a proton that produces a small E2 component that is mixed with the predominantly M1 excitation of the delta resonance.The magnitude of this E2 components provides a sensitive probe of the structure of the Nucleon.

Not Available

1991-01-01T23:59:59.000Z

271

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

SciTech Connect

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

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

1985-05-01T23:59:59.000Z

272

Design and operation of the electron beam ion trap  

SciTech Connect

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

Vogel, D.

1990-05-30T23:59:59.000Z

273

Effect of Beam Quality on the Scaling of High-Energy Flow Lasers  

Science Journals Connector (OSTI)

The maximum output power from high-energy flow lasers is primarily determined by the ... field intensity, however, depends on the beam quality that can be achieved with the laser ... of gas flow inhomogeneities o...

W. L. Bohn; Th. Hall

1987-01-01T23:59:59.000Z

274

Intra-pulse beam steering in a mid-infrared quantum cascade laser  

Science Journals Connector (OSTI)

The intra-pulse measurements of the beam steering in an AlGaAs/GaAs quantum cascade laser are presented in this paper. The experimental ... theoretical model. The near field of the laser radiation is calculated a...

Emilia Pruszy?ska-Karbownik; Kazimierz Regi?ski

2014-08-01T23:59:59.000Z

275

Creating a Well-focused Laser-accelerated Proton Beam as a Driver...  

Office of Science (SC) Website

Proton Beam as a Driver for Proton Fast Ignition Focusing of laser accelerated proton beams advances with a novel cone target design. Print Text Size: A A A Subscribe...

276

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

Science Journals Connector (OSTI)

The possibility of creating ceramic-metal joints by electron beam welding is considered. The welding of ... range (520 Pa) using a plasma electron source. The structure and composition of the ceramic ... breakin...

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

2012-09-01T23:59:59.000Z

277

R&D for a Soft X-Ray Free Electron Laser Facility  

E-Print Network (OSTI)

Quantum-degenerate Electron Source, Physical Review LettersHigh brightness electron source, beam instrumentation andFEL Requires high rep-rate electron source Beam switchyard

Staples, John

2009-01-01T23:59:59.000Z

278

Note: Characteristic beam parameter for the line electron gun  

SciTech Connect

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

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

2013-11-15T23:59:59.000Z

279

Lateral propagation of MeV electrons generated by femtosecond laser irradiation  

Science Journals Connector (OSTI)

The propagation of MeV electronsgenerated by intense ( ? 10 20 ? W / cm 2 ) femtosecond laser irradiation in the lateral direction perpendicular to the incident laser beam was studied using targets consisting of irradiated metal wires and neighboring spectator wires embedded in electrically conductive (aluminum) or resistive (Teflon) substrates. The K shell spectra in the energy range 4060 keV from wires of Gd Dy Hf and W were recorded by a transmission crystal spectrometer. The spectra were produced by 1s electron ionization in the irradiated wire and by energetic electron propagation through the substrate material to the spectator wire of a different metal. The electron range and energy were determined from the relative K shell emissions from the irradiated and spectator wires separated by varying substrate lateral distances of up to 1 mm. It was found that electron propagation through Teflon was inhibited compared to aluminum implying a relatively weak return current and incomplete space-charge neutralization. The energetic electron propagation in the direction parallel to the electric field of the laser beam was larger than perpendicular to the electric field. Energetic electron production was lower when directly irradiatingaluminum or Teflon compared to irradiating the heavy metal wires. These experiments are important for the determination of the energetic electron production mechanism and for understanding lateral electron propagation that can be detrimental to fast-ignition fusion and hard x-ray backlighter radiography.

J. F. Seely; C. I. Szabo; P. Audebert; E. Brambrink; E. Tabakhoff; L. T. Hudson

2010-01-01T23:59:59.000Z

280

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

Note: This page contains sample records for the topic "lasers electron beams" 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

Improving beam spectral and spatial quality by double-foil target in laser ion acceleration for ion-driven fast ignition  

SciTech Connect

Mid-Z ion driven fast ignition inertial fusion requires ion beams of 100s of MeV energy and < 10% energy spread. An overdense run-scale foil target driven by a high intensity laser pulse can produce an ion beam that has attractive properties for this application. The Break Out Afterburner (BOA) is one laser-ion acceleration mechanism proposed to generate such beams, however the late stages of the BOA tend to produce too large of an energy spread. The spectral and spatial qualities of the beam quickly evolve as the ion beam and co-moving electrons continue to interact with the laser. Here we show how use of a second target foil placed behind a nm-scale foil can substantially reduce the temperature of the co-moving electrons and improve the ion beam energy spread. Particle-In-Cell simulations reveal the dynamics of the ion beam under control. Optimal conditions for improving the spectral and spatial spread of the ion beam is explored for current laser and target parameters, leading to generation of ion beams of energy 100s of MeV and 6% energy spread, a vital step for realizing ion-driven fast ignition.

Huang, Chenkun [Los Alamos National Laboratory; Albright, Brian J [Los Alamos National Laboratory

2010-01-01T23:59:59.000Z

282

Electron cyclotron beam measurement system in the Large Helical Device  

SciTech Connect

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

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

2014-11-15T23:59:59.000Z

283

Ignition feedback regenerative free electron laser (FEL) amplifier  

DOE Patents (OSTI)

An ignition feedback regenerative amplifier consists of an injector, a linear accelerator with energy recovery, and a high-gain free electron laser amplifier. A fraction of the free electron laser output is coupled to the input to operate the free electron laser in the regenerative mode. A mode filter in this loop prevents run away instability. Another fraction of the output, after suitable frequency up conversion, is used to drive the photocathode. An external laser is provided to start up both the amplifier and the injector, thus igniting the system.

Kim, Kwang-Je (Burr Ridge, IL); Zholents, Alexander (Walnut Creek, CA); Zolotorev, Max (Oakland, CA)

2001-01-01T23:59:59.000Z

284

Bandstructure and electronic states in terahertz quantum cascade lasers  

Science Journals Connector (OSTI)

Bandstructure and electron eigenstates in terahertz Quantum Cascade Lasers (QCLs) are studied by using the Quantum Transmitting Boundary Method (QTBM). It has several advantages compared to the commonly used Transfer Matrix Method (TMM). ... Keywords: QCL, QTBM, TMM, bandstructure, electron eigenstates, nanoscale technology, nanotechnology, quantum cascade lasers, quantum transmitting boundary methods, transfer matrix methods

Jing Tao Lu; Jun Cheng Cao

2006-06-01T23:59:59.000Z

285

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-

286

Electron beam induced radio emission from ultracool dwarfs  

E-Print Network (OSTI)

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

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

2012-01-01T23:59:59.000Z

287

Disruption of Particle Detector Electronics by Beam Generated EMI  

SciTech Connect

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

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

2007-06-27T23:59:59.000Z

288

Small signal theory of an EB drifting electron laser  

Science Journals Connector (OSTI)

The concept of the drifting electron laser (DEL), powered by a relativistic beam of EB drifting electrons in crossed electric and magnetic fields, is introduced. The wiggling motion is generated by adding a periodic modulation in either E or B. In contrast to free electron lasers (FELs) converting kinetic energy and momentum into radiation, the emitted radiation energy and momentum in a DEL come respectively from the change in the electrostatic energy eE0 ?X and vector potential eB0 ?X of the electron, ?X being the quantum recoil of the guiding center (GC) location perpendicular to the drift direction. The difference between stimulated emission and absorption responsible for the gain is provided by the transverse gradient of the wiggler strength, and the gain curve is symmetric relative to the frequency detuning ??. Since the drift velocity and the resonance condition are energy independent, one avoids the low efficiency limits placed on FELs from energy detuning and thermal spreads. Beam energy spreads turn into spreads in the GC location, reducing the gain sensitivity to the beam quality. Saturation in a DEL occurs via the off-axis walk of the emitting electrons. Overlap between the beam and the radiation is maintained by a small tilt of the resonator axis relative to the EB drift direction.

Spilios Riyopoulos

1997-02-01T23:59:59.000Z

289

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

290

Dominant Secondary Nuclear Photoexcitation with the X-ray Free Electron Laser  

E-Print Network (OSTI)

The new regime of resonant nuclear photoexcitation rendered possible by x-ray free electron laser beams interacting with solid state targets is investigated theoretically. Our results unexpectedly show that secondary processes coupling nuclei to the atomic shell in the created cold high-density plasma can dominate direct photoexcitation. As an example we discuss the case of $^{93m}$Mo isomer depletion for which nuclear excitation by electron capture as secondary process is shown to be orders of magnitude more efficient than the direct laser-nucleus interaction. General arguments revisiting the role of the x-ray free electron laser in nuclear experiments involving solid-state targets are further deduced.

Jonas Gunst; Yuri A. Litvinov; Christoph H. Keitel; Adriana Plffy

2014-02-27T23:59:59.000Z

291

Experimental Time Resolved Electron Beam Temperature Measurements Using Bremsstrahlung Diagnostics  

SciTech Connect

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

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

1999-06-25T23:59:59.000Z

292

Fusion reactions initiated by laser-accelerated particle beams in a laser-produced plasma  

E-Print Network (OSTI)

The advent of high-intensity pulsed laser technology enables the generation of extreme states of matter under conditions that are far from thermal equilibrium. This in turn could enable different approaches to generating energy from nuclear fusion. Relaxing the equilibrium requirement could widen the range of isotopes used in fusion fuels permitting cleaner and less hazardous reactions that do not produce high energy neutrons. Here we propose and implement a means to drive fusion reactions between protons and boron-11 nuclei, by colliding a laser-accelerated proton beam with a laser-generated boron plasma. We report proton-boron reaction rates that are orders of magnitude higher than those reported previously. Beyond fusion, our approach demonstrates a new means for exploring low-energy nuclear reactions such as those that occur in astrophysical plasmas and related environments.

Labaune, C; Depierreux, S; Goyon, C; Loisel, G; Yahia, V; Rafelski, J

2013-01-01T23:59:59.000Z

293

Conceptual design for an electron-beam heated hypersonic wind tunnel  

SciTech Connect

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

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

1997-07-01T23:59:59.000Z

294

LIPSS Free-Electron Laser Searches for Dark Matter  

SciTech Connect

A variety of Dark Matter particle candidates have been hypothesized by physics Beyond the Standard Model (BSM) in the very light (10{sup -6} - 10{sup -3} eV) range. In the past decade several international groups have conducted laboratory experiments designed to either produce such particles or extend the boundaries in parameter space. The LIght Pseudo-scalar and Scalar Search (LIPSS) Collaboration, using the 'Light Shining through a Wall' (LSW) technique, passes the high average power photon beam from Jefferson Lab's Free-Electron Laser through a magnetic field upstream from a mirror and optical beam dump. Light Neutral Bosons (LNBs), generated by coupling of photons with the magnetic field, pass through the mirror ('the Wall') into an identical magnetic field where they revert to detectable photons by the same coupling process. While no evidence of LNBs was evident, new scalar coupling boundaries were established. New constraints were also determined for hypothetical para-photons and for millicharged fermions. We will describe our experimental setup and results for LNBs, para-photons, and milli-charged fermions. Plans for chameleon particle searches are underway.

Afanaciev, Andrei; Beard, Kevin; Biallas, George; Boyce, James R; Minarni, M; Ramdon, R; Robinson, Taylor; Shinn, Michelle D

2011-09-01T23:59:59.000Z

295

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

296

Beam-dynamics Simulations for Channeling Radiation Electron Source  

Science Journals Connector (OSTI)

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

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

2014-01-01T23:59:59.000Z

297

MeV-Energy X Rays from Inverse Compton Scattering with Laser-Wakefield Accelerated Electrons  

Science Journals Connector (OSTI)

We report the generation of MeV x rays using an undulator and accelerator that are both driven by the same 100-terawatt laser system. The laser pulse driving the accelerator and the scattering laser pulse are independently optimized to generate a high energy electron beam (>200??MeV) and maximize the output x-ray brightness. The total x-ray photon number was measured to be ?1107, the source size was 5???m, and the beam divergence angle was ?10??mrad. The x-ray photon energy, peaked at 1MeV (reaching up to 4MeV), exceeds the thresholds of fundamental nuclear processes (e.g., pair production and photodisintegration).

S. Chen; N. D. Powers; I. Ghebregziabher; C. M. Maharjan; C. Liu; G. Golovin; S. Banerjee; J. Zhang; N. Cunningham; A. Moorti; S. Clarke; S. Pozzi; D. P. Umstadter

2013-04-10T23:59:59.000Z

298

Portable radiography system using a relativistic electron beam  

DOE Patents (OSTI)

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

Hoeberling, R.F.

1987-09-22T23:59:59.000Z

299

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

300

Influence of space charge wave on quasilinear theory of the free-electron laser saturation  

SciTech Connect

A quasilinear theory is presented that describes the self-consistent evolution of the electron beam distribution function and fields in a free-electron laser when the space charge wave is present. In the Raman regime, a high-density electron beam has an appreciable space charge potential. A broad spectrum of waves is assumed in order to have a relatively wide range of resonant particles. A one-dimensional helical magnetic field is considered and the analysis is based on the Vlasov-Maxwell equations. Two coupled differential equations are derived, which, in conjunction with conservation laws, describe the quasilinear development by the diffusion of electrons in the momentum space. This leads to the saturation of the free-electron laser instability by the plateau formation. Analytical expressions for the growth rate and for the diffusion coefficient are derived, which reduced to those in the Compton regime under appropriate conditions. By use of the linear growth rate and diffusion coefficient, an analytical expression for efficiency in Raman regime was derived. A numerical analysis is conducted to study the effects of the spectral width of radiation and the thermal spread of the electron beam on the efficiency.

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

2009-07-15T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

Single Crystal Diamond Beam Position Monitors with Radiofrequency Electronic Readout  

SciTech Connect

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

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

2010-06-23T23:59:59.000Z

302

A combined beta-beam and electron capture neutrino experiment  

E-Print Network (OSTI)

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

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

2009-02-27T23:59:59.000Z

303

Molecular-beam epitaxy growth and characterization of mid-infrared quantum cascade laser structures  

Science Journals Connector (OSTI)

The development of molecular-beam epitaxy (MBE) of GaAs/AlGaAs heterostructures, used for fabrication of ~9?m quantum cascade lasers (QCLs), is reported. The X-ray diffractometry (XRD) structural characterization, as an integral part of this process, ... Keywords: GaAs/AlGaAs lasers, Intersubband transitions, Mid-infrared, Molecular-beam epitaxy, Quantum cascade laser, Unipolar devices

Kamil Kosiel; Justyna Kubacka-Traczyk; Piotr Karbownik; Anna Szerling; Jan Muszalski; Maciej Bugajski; Przemek Romanowski; Jaros?aw Gaca; Marek Wjcik

2009-03-01T23:59:59.000Z

304

STANDARD OPERATING PROCEDURES Spectra Physics BeamLok 2080-12 Argon Laser  

E-Print Network (OSTI)

ignition) several seconds later and the laser is ready to lase. After another several seconds, the current1 STANDARD OPERATING PROCEDURES Spectra Physics BeamLok 2080-12 Argon Laser (Revised 1/22/04) Important things to know: · Always run the laser in current mode. This operates at a more consistent output

305

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

306

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

307

Multiple-beam laserplasma interactions in inertial confinement fusion  

SciTech Connect

The experimental evidence for multiple-beam laser-plasma instabilities of relevance to laser driven inertial confinement fusion at the ignition scale is reviewed, in both the indirect and direct-drive approaches. The instabilities described are cross-beam energy transfer (in both indirectly driven targets on the NIF and in direct-drive targets), multiple-beam stimulated Raman scattering (for indirect-drive), and multiple-beam two-plasmon decay instability (in direct drive). Advances in theoretical understanding and in the numerical modeling of these multiple beam instabilities are presented.

Myatt, J. F., E-mail: jmya@lle.rochester.edu; Zhang, J.; Maximov, A. V. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Department of Mechanical Engineering, University of Rochester, Rochester, New York 14627 (United States); Short, R. W.; Seka, W.; Edgell, D. H.; Michel, D. T.; Igumenshchev, I. V. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Froula, D. H. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627-0171 (United States); Hinkel, D. E.; Michel, P.; Moody, J. D. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551-0808 (United States)

2014-05-15T23:59:59.000Z

308

Short pulse laser produced energetic electron and positron measurements  

SciTech Connect

Very energetic (>MeV) electrons are commonly produced from ultraintense (>10{sup 19} W/cm{sup 2}) laser-solid interactions. Diagnosing these so-called hot electrons is of fundamental importance in understanding the detailed laser plasma physics present in these interactions, as well as in potential applications. Interestingly, positrons can also be produced in these interactions if the number and effective temperature of hot electrons exceed a threshold value. This additional information may help to better determine the effective electron temperature that exists in these targets. We have designed and constructed a compact spectrometer that can simultaneously measure the energy spectra of both electrons and positrons. Presented here are the principles of the spectrometer together with its experimental results obtained on the ultraintense (>10{sup 19} W/cm{sup 2}) lasers at Lawrence Livermore National Laboratory and the Rutherford Appleton Laboratory Vulcan petawatt laser.

Chen, Hui; Wilks, Scott C.; Patel, Parvesh K.; Shepherd, Ronnie [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

2006-10-15T23:59:59.000Z

309

Tunable Radiation Source by Coupling Laser-Plasma-Generated Electrons to a Periodic Structure  

SciTech Connect

Near-infrared radiation around 1000 nm generated from the interaction of a high-density MeV electron beam, obtained by impinging an intense ultrashort laser pulse on a solid target, with a metal grating is observed experimentally. Theoretical modeling and particle-in-cell simulation suggest that the radiation is caused by the Smith-Purcell mechanism. The results here indicate that tunable terahertz radiation with tens GV/m field strength can be achieved by using appropriate grating parameters.

Jin, Z. [Photon Pioneers Center, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871 (Japan); Chen, Z. L.; Kon, A.; Nakatsutsumi, M. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871 (Japan); Zhuo, H. B. [Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871 (Japan); School of Science, National University of Defense Technology, Changsha 410073 (China); Wang, H. B.; Zhang, B. H.; Gu, Y. Q.; Wu, Y. C.; Zhu, B.; Wang, L. [National Key Laboratory of Laser Fusion, CAEP, Mianyang 621900 (China); Yu, M. Y. [Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China); Institute for Theoretical Physics I, Ruhr University, Bochum D-44780 (Germany); Sheng, Z. M. [Key Laboratory for Laser Plasmas (Ministry of Education) and Department of Physics, Shanghai Jiao Tong University, Shanghai 200240 (China); Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, CAS, Beijing 100080 (China); Kodama, R. [Photon Pioneers Center, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871 (Japan); Graduate School of Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka, 565-0871 (Japan); Institute of Laser Engineering, Osaka University, 2-6 Yamada-oka, Suita, Osaka, 565-0871 (Japan)

2011-12-23T23:59:59.000Z

310

Apparatus and method for increasing the bandwidth of a laser beam  

DOE Patents (OSTI)

A method and apparatus is disclosed that provides a laser output beam having a broad bandwidth and an intensity smooth over time. The bandwidth of the laser output can be varied easily by varying the intensity of a broadband source. The present invention includes an optical modulation apparatus comprising a narrowband laser that outputs a horizontally polarized beam (a "signal beam") and a broadband laser that outputs a vertically polarized beam (a "pump beam") whose intensity varies rapidly. The two beam are coupled into a birefringent laser material so that the respective polarizations coincide with the principal axes of the material. As the two beams travel through the material, the polarization preserving properties of the birefringent material maintain the respective polarizations of the two beam; however there is coupling between the two beams as a result of cross phase modulations, which induces a bandwidth change of the signal beam. The amount of bandwidth change is dependent upon the average intensity of the pump beam. The beams are coupled out from the birefringent material and the modulated signal beam is separated by a polarization selector. The modulated signal beam now has a wider bandwidth, and its shape remains smooth in time. This signal beam can be applied to incoherence inducing systems. The different bandwidths required by these different incoherence inducing systems can be obtained by varying the intensity of the pump beam. The United States Government has rights in this invention pursuant to Contract No. W7405-ENG-48 between the United States Department of Energy and the University of California for the operation of Lawrence Livermore National Laboratory.

Chaffee, Paul H. (Bolina, CA)

1991-01-01T23:59:59.000Z

311

Hohlraum Symmetry Experiments with Multiple Beam Cones on the Omega Laser Facility  

SciTech Connect

Symmetry experiments have been performed on the Omega laser facility using cylindrical hohlraum targets with as many as 40thinspthinspbeams arranged into multiple beam cones. These experiments constitute a first step in the development of {open_quotes}beam phasing{close_quotes} in which beams are arranged into multiple beam cones, forming multiple rings of beam spots on the inner surface of a cylindrical hohlraum, and demonstrate the ability to model hohlraums incorporating multiple beam cones and to tune the time-integrated capsule flux asymmetry by adjustment of the beam pointing. {copyright} {ital 1998} {ital The American Physical Society}

Murphy, T.J.; Wallace, J.M.; Delamater, N.D.; Barnes, C.W.; Gobby, P.; Hauer, A.A.; Lindman, E.; Magelssen, G.; Moore, J.B.; Oertel, J.A.; Watt, R. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)] [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Landen, O.L.; Amendt, P.; Cable, M.; Decker, C.; Hammel, B.A.; Koch, J.A.; Suter, L.J.; Turner, R.E.; Wallace, R.J. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Marshall, F.J.; Bradley, D.; Craxton, R.S.; Keck, R.; Knauer, J.P.; Kremens, R.; Schnittman, J.D. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14627 (United States)] [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14627 (United States)

1998-07-01T23:59:59.000Z

312

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

313

Practical method and device for enhancing pulse contrast ratio for lasers and electron accelerators  

DOE Patents (OSTI)

An apparatus and method for enhancing pulse contrast ratios for drive lasers and electron accelerators. The invention comprises a mechanical dual-shutter system wherein the shutters are placed sequentially in series in a laser beam path. Each shutter of the dual shutter system has an individually operated trigger for opening and closing the shutter. As the triggers are operated individually, the delay between opening and closing first shutter and opening and closing the second shutter is variable providing for variable differential time windows and enhancement of pulse contrast ratio.

Zhang, Shukui; Wilson, Guy

2014-09-23T23:59:59.000Z

314

Physics Reach of Electron-Capture Neutrino Beams  

E-Print Network (OSTI)

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

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

2005-10-21T23:59:59.000Z

315

Self-truncated ionization injection and consequent monoenergetic electron bunches in laser wakefield acceleration  

SciTech Connect

The ionization-induced injection in laser wakefield acceleration has been recently demonstrated to be a promising injection scheme. However, the energy spread controlling in this mechanism remains a challenge because continuous injection in a mixed gas target is usually inevitable. Here, we propose that by use of certain initially unmatched laser pulses, the electron injection can be constrained to the very front region of the mixed gas target, typically in a length of a few hundreds micrometers determined by the laser self-focusing and the wake deformation. As a result, the produced electron beam has narrow energy spread and meanwhile contains tens of pC in charge. Both multidimensional simulations and theoretical analysis illustrate the effectiveness of this scheme.

Zeng, Ming; Zhang, Jie [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)] [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Chen, Min, E-mail: minchen@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China) [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Mathematics, Institute of Natural Sciences, and MOE-LSC, Shanghai Jiao Tong University, Shanghai 20040 (China); Sheng, Zheng-Ming, E-mail: zmsheng@sjtu.edu.cn [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China) [Key Laboratory for Laser Plasmas (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China); SUPA, Department of Physics, University of Strathclyde, Glasgow G4 0NG (United Kingdom); Mori, Warren B. [University of California, Los Angeles, California 90095 (United States)] [University of California, Los Angeles, California 90095 (United States)

2014-03-15T23:59:59.000Z

316

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

317

Apparatus and process for active pulse intensity control of laser beam  

DOE Patents (OSTI)

An optically controlled laser pulse energy control apparatus and process is disclosed wherein variations in the energy of a portion of the laser beam are used to vary the resistance of a photodetector such as a photoresistor through which a control voltage is fed to a light intensity controlling device through which a second portion of the laser beam passes. Light attenuation means are provided to vary the intensity of the laser light used to control the resistance of the photodetector. An optical delay path is provided through which the second portion of the beam travels before reaching the light intensity controlling device. The control voltage is supplied by a variable power supply. The apparatus may be tuned to properly attenuate the laser beam passing through the intensity controlling device by adjusting the power supply, the optical delay path, or the light attenuating means.

Wilcox, Russell B. (Oakland, CA)

1992-01-01T23:59:59.000Z

318

Development of a chemical dosimeter for electron beam food irradiation  

E-Print Network (OSTI)

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

Rivadeneira, Ramiro Geovanny

2006-08-16T23:59:59.000Z

319

Risk Management Plan Electron Beam Ion Source Project  

E-Print Network (OSTI)

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

320

RiS-M-2401 DOSIMETRY FOR ELECTRON BEAM APPLICATIONS  

E-Print Network (OSTI)

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

Note: This page contains sample records for the topic "lasers electron beams" 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

A Proof-of-Principle Echo-enabled Harmonic Generation Free Electron Laser Experiment at SLAC  

SciTech Connect

With the advent of X-ray Free Electron Lasers (FELs), new methods have been developed to extend capabilities at short wavelengths beyond Self-Amplified Spontaneous Emission (SASE). In particular, seeding of a FEL allows for temporal control of the radiation pulse and increases the peak brightness by orders of magnitude. Most recently, Gennady Stupakov and colleagues at SLAC proposed a new technique: Echo-Enabled Harmonic Generation (EEHG). Here a laser microbunches the beam in an undulator and the beam is sheared in a chicane. This process is repeated with a second laser, undulator and chicane. The interplay between these allows a seeding of the X-ray laser up to the 100th harmonic of the first laser. After introducing the physics of FELs and the EEHG seeding technique, we describe contributions to the experimental effort. We will present detailed studies of the experiment including the choice of parameters and their optimization, the emittance effect, spontaneous emission in the undulators, the second laser phase effect, and measurements of the jitter between RF stations. Finally, the status and preliminary results of the Echo-7 experiment will be outlined.

Pernet, Pierre-Louis; /Ecole Polytechnique, Lausanne /SLAC

2012-01-06T23:59:59.000Z

322

A Far-infrared Undulator for Coherent Synchrotron Radiation and Free Electron Laser at Tohoku University  

SciTech Connect

In order to develop an intense far-infrared radiation source, a high quality electron beam has been studied at Tohoku University, Sendai. The bunch length of the beam expected is very much shorter than terahertz (THz) wavelength, so that coherent spontaneous emission of synchrotron radiation will be a promising high brilliant far-infrared source. An undulator consisting of permanent magnets has been designed in which optional free electron laser (FEL) will be operated in free space mode. Consequently the minimum gap of the undulator is decided to be 54 mm for 0.36 mm radiation to avoid diffraction loss, and then the period length of 10 cm is employed. The undulator may cover a wavelength range from 0.18 to 0.36 mm with the beam energy of 17 MeV. Property of coherent THz radiation from the undulator and possibility of novel pre-bunched THz FEL is discussed.

Hama, Hiroyuki; Hinode, Fujio; Kawai, Masayuki; Nanbu, Kenichi; Miyahara, Fusashi; Yasuda, Mafuyu [Laboratory of Nuclear Science, Tohoku University School of Science, 1-2-1 Mikamine, Taihaku-ku, Sendai 982-0826 (Japan)

2010-06-23T23:59:59.000Z

323

Direct laser acceleration of electrons in free-space  

E-Print Network (OSTI)

Compact laser-driven accelerators are versatile and powerful tools of unarguable relevance on societal grounds for the diverse purposes of science, health, security, and technology because they bring enormous practicality to state-of-the-art achievements of conventional radio-frequency accelerators. Current benchmarking laser-based technologies rely on a medium to assist the light-matter interaction, which impose material limitations or strongly inhomogeneous fields. The advent of few cycle ultra-intense radially polarized lasers has materialized an extensively studied novel accelerator that adopts the simplest form of laser acceleration and is unique in requiring no medium to achieve strong longitudinal energy transfer directly from laser to particle. Here we present the first observation of direct longitudinal laser acceleration of non-relativistic electrons that undergo highly-directional multi-GeV/m accelerating gradients. This demonstration opens a new frontier for direct laser-driven particle accelerati...

Carbajo, Sergio; Wong, Liang Jie; Miller, R J Dwayne; Krtner, Franz X

2015-01-01T23:59:59.000Z

324

Chirped pulse inverse free-electron laser vacuum accelerator  

DOE Patents (OSTI)

A chirped pulse inverse free-electron laser (IFEL) vacuum accelerator for high gradient laser acceleration in vacuum. By the use of an ultrashort (femtosecond), ultrahigh intensity chirped laser pulse both the IFEL interaction bandwidth and accelerating gradient are increased, thus yielding large gains in a compact system. In addition, the IFEL resonance condition can be maintained throughout the interaction region by using a chirped drive laser wave. In addition, diffraction can be alleviated by taking advantage of the laser optical bandwidth with negative dispersion focusing optics to produce a chromatic line focus. The combination of these features results in a compact, efficient vacuum laser accelerator which finds many applications including high energy physics, compact table-top laser accelerator for medical imaging and therapy, material science, and basic physics.

Hartemann, Frederic V. (Dublin, CA); Baldis, Hector A. (Pleasanton, CA); Landahl, Eric C. (Walnut Creek, CA)

2002-01-01T23:59:59.000Z

325

Simulations of the rocketdyne free-electron laser  

SciTech Connect

Rocketdyne is assembling a high-brightness 78 MeV free-electron laser (FEL). In this paper performance calculations using the Rocketdyne FELOPT code are presented for a 1.06 {mu}m system.

Cover, R.A.; Bennett, G.T.; Burke, R.J.; Curtin, M.S.; Lampel, M.C.; Rakowsky, G. (Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.)

1991-12-01T23:59:59.000Z

326

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

Science Journals Connector (OSTI)

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

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

1989-01-01T23:59:59.000Z

327

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

328

Electron Spectrometer: XPS with Laser Interface | EMSL  

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

be analyzed. Special modifications include several quartz and lithium fluoride laser ports, such that unique opportunities have been created for the use of ultraviolet and...

329

ELECTRON-BEAM-INDUCED RADIO EMISSION FROM ULTRACOOL DWARFS  

SciTech Connect

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

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

2012-06-10T23:59:59.000Z

330

Electron Dynamics in Nanostructures in Strong Laser Fields  

SciTech Connect

The goal of our research was to gain deeper insight into the collective electron dynamics in nanosystems in strong, ultrashort laser fields. The laser field strengths will be strong enough to extract and accelerate electrons from the nanoparticles and to transiently modify the materials electronic properties. We aimed to observe, with sub-cycle resolution reaching the attosecond time domain, how collective electronic excitations in nanoparticles are formed, how the strong field influences the optical and electrical properties of the nanomaterial, and how the excitations in the presence of strong fields decay.

Kling, Matthias

2014-09-11T23:59:59.000Z

331

Systems for controlling the intensity variations in a laser beam and for frequency conversion thereof  

DOE Patents (OSTI)

In order to control the intensity of a laser beam so that its intensity varies uniformly and provides uniform illumination of a target, such as a laser fusion target, a broad bandwidth laser pulse is spectrally dispersed spatially so that the frequency components thereof are spread apart. A disperser (grating) provides an output beam which varies spatially in wavelength in at least one direction transverse to the direction of propagation of the beam. Temporal spread (time delay) across the beam is corrected by using a phase delay device (a time delay compensation echelon). The dispersed beam may be amplified with laser amplifiers and frequency converted (doubled, tripled or quadrupled in frequency) with nonlinear optical elements (birefringent crystals). The spectral variation across the beam is compensated by varying the angle of incidence on one of the crystals with respect to the crystal optical axis utilizing a lens which diverges the beam. Another lens after the frequency converter may be used to recollimate the beam. The frequency converted beam is recombined so that portions of different frequency interfere and, unlike interference between waves of the same wavelength, there results an intensity pattern with rapid temoral oscillations which average out rapidly in time thereby producing uniform illumination on target. A distributed phase plate (also known as a random phase mask), through which the spectrally dispersed beam is passed and then focused on a target, is used to provide the interference pattern which becomes nearly modulation free and uniform in intensity in the direction of the spectral variation.

Skupsky, Stanley (Rochester, NY); Craxton, R. Stephen (Rochester, NY); Soures, John (Pittsford, NY)

1990-01-01T23:59:59.000Z

332

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

333

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

334

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

SciTech Connect

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

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

2013-12-01T23:59:59.000Z

335

In the OSTI Collections: Free-Electron Lasers | OSTI, US Dept of Energy,  

Office of Scientific and Technical Information (OSTI)

Free-Electron Lasers Free-Electron Lasers Existing Free-Electron Lasers Using Free-Electron Lasers for Measurement and Defense New Free-Electron Laser Designs References Research Organizations Reports available from OSTI's Information Bridge While most types of laser produce coherent light from electric charges bound within atoms, molecules, or solids, unbound charges are the light source in free-electron lasers. Lasers of this type can operate at higher frequencies than are easily achieved with bound-electron lasers. Various uses and designs of free-electron lasers are the focus of different projects sponsored through the Department of Energy. Lasers, like any source of light or other electromagnetic waves, produce waves when some of the electric charges they contain go from having a

336

Realization of a high energy, high beam quality CO2 laser using a SFUR cavity  

Science Journals Connector (OSTI)

We have obtained a source with a high beam qualty and output energy, which could be useful for laser-surface interaction studies. A very promising injection method has been tested in a very critical configurat...

P. L. Belli; G. Bitelli; F. D'Amato

1989-12-01T23:59:59.000Z

337

Researchers' Hottest New Laser Beams 14.2 kW | Jefferson Lab  

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

Researchers' Hottest New Laser Beams 14.2 kW For more information: Office of Naval Research press release The linear accelerator portion of the FEL. On Thursday, Oct. 26,...

338

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

E-Print Network (OSTI)

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

Duan, Huigao

339

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

E-Print Network (OSTI)

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

340

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

Science Journals Connector (OSTI)

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

M. Ghanashyam Krishna; G. K. Muralidhar

1990-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

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

342

Monochromatic short pulse laser produced ion beam using a compact passive magnetic device  

SciTech Connect

High-intensity laser accelerated protons and ions are emerging sources with complementary characteristics to those of conventional sources, namely high charge, high current, and short bunch duration, and therefore can be useful for dedicated applications. However, these beams exhibit a broadband energy spectrum when, for some experiments, monoenergetic beams are required. We present here an adaptation of conventional chicane devices in a compact form (10 cm 20 cm) which enables selection of a specific energy interval from the broadband spectrum. This is achieved by employing magnetic fields to bend the trajectory of the laser produced proton beam through two slits in order to select the minimum and maximum beam energy. The device enables a production of a high current, short duration source with a reproducible output spectrum from short pulse laser produced charged particle beams.

Chen, S. N.; Gauthier, M.; Higginson, D. P.; Dorard, S.; Marqus, J.-R.; Fuchs, J. [LULI, cole Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France)] [LULI, cole Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France); Mangia, F.; Atzeni, S. [Dipartimento SBAI, Universit di Roma La Sapienza, Roma (Italy)] [Dipartimento SBAI, Universit di Roma La Sapienza, Roma (Italy); Riquier, R. [LULI, cole Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France) [LULI, cole Polytechnique, CNRS, CEA, UPMC, 91128 Palaiseau (France); CEA, DAM, DIF, F-91297 Arpajon (France)

2014-04-15T23:59:59.000Z

343

Wiggler plane focusing in a linear free electron laser  

DOE Patents (OSTI)

This disclosure describes a free electron laser apparatus that provides a magnetic centering force to turn or focus a non-axial electron toward the longitudinal axis as desired. The focusing effect is provided by wiggler magnet pole faces that are approximately parabolically shaped.

Scharlemann, E.T.

1985-11-21T23:59:59.000Z

344

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

345

Effect of electron beam misalignments on the gyrotron efficiency  

SciTech Connect

The theory describing the operation of gyrotrons with tilted and shifted electron beams has been developed. Effects of the tilt and shift are studied for a 1 MW, 170 GHz gyrotron, which is presently under development in Europe for electron cyclotron resonance plasma heating and current drive in the International Thermonuclear Experimental Reactor. It is shown that one should expect significant deterioration of gyrotron operation in such gyrotrons when the tilt angle exceeds 0.40.5 and the parallel shift of the beam axis with respect to the axis of a microwave circuit is larger than 0.40.5 mm. At the same time, simultaneous tilting and shifting in a proper manner can mitigate this deteriorating effect.

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

2013-07-15T23:59:59.000Z

346

Silicon buried gratings for dielectric laser electron accelerators  

SciTech Connect

This paper describes design and simulations of dielectric laser electron accelerators that achieve Gigavolt-per-meter (GV/m) accelerating gradients and wide electron channels (>1??m). The accelerator design is based on a silicon buried grating structure that enables flexible phase synchronization, large electron channel fields, and low standing-wave ratio in the material. This design increases the accelerating gradients to more than double those of reported quartz grating accelerators, thereby reducing the input laser fluence by 60% for the same accelerating gradient. With a 100 fs pulsed laser, our silicon buried gratings can achieve a maximum gradient of 1.1 GV/m, indicating that these accelerators have potential for numerous electron-accelerator applications.

Chang, Chia-Ming, E-mail: cachang@alumni.stanford.edu [Bell Labs, Alcatel-Lucent, 791 Holmdel Road, Holmdel, New Jersey 07733 (United States); Solgaard, Olav [E. L. Ginzton Lab., Stanford University, Stanford, California 94305 (United States)

2014-05-05T23:59:59.000Z

347

Characterization of electron beam melted uranium - 6% niobium ingots  

SciTech Connect

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

McKoon, R.H.

1997-10-31T23:59:59.000Z

348

Electron Beam Diagnostics using Coherent Cherenkov Radiation in Aerogel  

SciTech Connect

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

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

2009-01-22T23:59:59.000Z

349

Fundamental Proximity Effects in Focused electron Beam Induced Deposition  

SciTech Connect

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

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

2012-01-01T23:59:59.000Z

350

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

SciTech Connect

Modifications have been implemented in the Penning-Malmberg device ELTRAP aimed at performing studies on the dynamics of space-charge dominated nanosecond electron bunches traveling along the magnetic field. In particular, a Thomson backscattering apparatus has been developed where an infrared (IR) laser pulse collides with the bunched electron beam. The frequency-shifted backscattered radiation, acquired by means of a photomultiplier (PMT), can be exploited to evaluate information on energy, energy spread and density of the bunch. The achievable sensitivity of the diagnostics has been estimated, and valuable information on the main parameters affecting the signal-to-noise (S/N) ratio has been obtained [B. Paroli, F. Cavaliere, M. Cavenago, F. De Luca, M. Ikram, G. Maero, C. Marini, R. Pozzoli, and M. Rome, JINST 7, P01008 (2012)]. A series of upgrades are under way, aimed at increasing the S/N ratio through the use of a new laser for the electron source, the insertion of a stray light shield, and the optimization of the detection electronics. Moreover, electromagnetic simulations relevant to the design and implementation of a microwave heating system are presented. The generation of an electron plasma in ELTRAP by means of a low-power radio frequency (RF) drive in the MHz range applied on one of the trap electrodes and under ultra-high vacuum (UHV) conditions has previously been demonstrated [B. Paroli, F. De Luca, G. Maero, F. Pozzoli, and M. Rome, Plasma Sources Sci. Technol. 19, 045013 (2010)]. The new heating system will allow the extension of the RF studies to the GHz range and in particular the production of a more energetic electron plasma via cyclotron resonant excitation.

Rome, M.; Cavaliere, F.; Maero, G.; Paroli, B.; Pozzoli, R. [INFN Sezione di Milano and Dipartimento di Fisica, Universita degli Studi di Milano, Via Celoria 16, I-20133 Milano (Italy); Cavenago, M. [INFN Laboratori Nazionali di Legnaro, Viale dell'Universita 2, I-35020 Legnaro (Italy); Ikram, M. [INFN Sezione di Milano and Dipartimento di Fisica, Universita degli Studi di Milano, Via Celoria 16, I-20133 Milano, Italy and Department of Physics, Hazara University, 21300 Mansehra (Pakistan)

2013-03-19T23:59:59.000Z

351

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

E-Print Network (OSTI)

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

Eisenstein, Gadi

352

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

E-Print Network (OSTI)

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

Eisenstein, Gadi

353

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

E-Print Network (OSTI)

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

Eisenstein, Gadi

354

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

E-Print Network (OSTI)

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

355

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

E-Print Network (OSTI)

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

356

Production of a keV X-Ray Beam from Synchrotron Radiation in Relativistic Laser-Plasma Interaction  

E-Print Network (OSTI)

Production of a keV X-Ray Beam from Synchrotron Radiation in Relativistic Laser-Plasma Interaction demonstrate that a beam of x-ray radiation can be generated by simply focusing a single high- intensity laser spectral range) [6]. Laser-driven K x-ray sources [7­9] radiate subnanometer wavelength radiation

Umstadter, Donald

357

Vacuum electron acceleration by using two variable frequency laser pulses  

SciTech Connect

A method is proposed for producing a relativistic electron bunch in vacuum via direct acceleration by using two frequency-chirped laser pulses. We consider the linearly polarized frequency-chiped Hermit-Gaussian 0, 0 mode lasers with linear chirp in which the local frequency varies linearly in time and space. Electron motion is investigated through a numerical simulation using a three-dimensional particle trajectory code in which the relativistic Newton's equations of motion with corresponding Lorentz force are solved. Two oblique laser pulses with proper chirp parameters and propagation angles are used for the electron acceleration along the z-axis. In this way, an electron initially at rest located at the origin could achieve high energy, ?=319 with the scattering angle of 1.02{sup ?} with respect to the z-axis. Moreover, the acceleration of an electron in different initial positions on each coordinate axis is investigated. It was found that this mechanism has the capability of producing high energy electron microbunches with low scattering angles. The energy gain of an electron initially located at some regions on each axis could be greatly enhanced compared to the single pulse acceleration. Furthermore, the scattering angle will be lowered compared to the acceleration by using laser pulses propagating along the z-axis.

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

2013-12-15T23:59:59.000Z

358

Passively Q-switched Nd:YAG/Cr$^{4+}$:YAG All-Ceramics, Composite, Monolithic Micro-Lasers with Multi-Beam Output for Laser Ignition  

Science Journals Connector (OSTI)

High-peak power passively Q-switched Nd:YAG/Cr$^{4+}$:YAG monolithic micro-lasers with two- and three-beam output were realized. These compact laser devices, which can be used as...

Pavel, Nicolaie; Tsunekane, Masaki; Taira, Takunori

359

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

E-Print Network (OSTI)

-ultraviolet to X-ray region. Recently, injection of a single-pass FEL by the third laser harmonic of a TiLETTERS Injection of harmonics generated in gas in a free-electron laser providing intense-electron lasers promise to extend this down to femtosecond timescales. The process by which free-electron lasers

Loss, Daniel

360

Present and future perspectives for high energy density physics with intense heavy ion and laser beams  

E-Print Network (OSTI)

Present and future perspectives for high energy density physics with intense heavy ion and laser18, deliver an intense uranium beam that deposit about 1 kJ0g specific energy in solid matter. Using 2004! Abstract Intense heavy ion beams from the Gesellschaft für Schwerionenforschung ~GSI, Darmstadt

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


361

Application of a Laser-Wakefield Driven Monochromatic Photon Source to  

E-Print Network (OSTI)

) is a 100-TW, 30-fs pulsed Ti:sapphire laser system. Diocles routinely provides electron beams exhibiting

Umstadter, Donald

362

Generation of circularly polarized multiple high-order harmonic emission from two-color crossed laser beams  

E-Print Network (OSTI)

laser beams Xiao-Min Tong and Shih-I Chu Department of Chemistry, University of Kansas and Kansas Center field and a linearly polarized second-harmonic laser field, in crossed-beam con- figuration second-harmonic field, in crossed-beam configuration. We demonstrate the feasibility of such a scheme

Chu, Shih-I

363

Active manipulation of the spatial energy distribution of laser-accelerated proton beams  

Science Journals Connector (OSTI)

The spatial energy distributions of beams of protons accelerated by ultrahigh intensity (>1019W?cm2) picosecond laser pulse interactions with thin foil targets are investigated. Using separate, low intensity (<1013W?cm2) nanosecond laser pulses, focused onto the front surface of the target foil prior to the arrival of the high intensity pulse, it is demonstrated that the proton beam profile can be actively manipulated. In particular, results obtained with an annular intensity distribution at the focus of the low intensity beam are presented, showing smooth proton beams with a sharp circular boundary at all energies, which represents a significant improvement in the beam quality compared to irradiation with the picosecond beam alone.

D. C. Carroll; P. McKenna; O. Lundh; F. Lindau; C.-G. Wahlstrm; S. Bandyopadhyay; D. Pepler; D. Neely; S. Kar; P. T. Simpson; K. Markey; M. Zepf; C. Bellei; R. G. Evans; R. Redaelli; D. Batani; M. H. Xu; Y. T. Li

2007-12-12T23:59:59.000Z

364

Part 2: Coherent emission from Free Electron Lasers  

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

0 0 Electron beam-based sources of ultrashort x-ray pulses Alexander Zholents Advanced Photon Source, Argonne National Laborator , Argonne, IL 60439 (September 7, 2010) To be published by World Scientific Publishing Co. in Reviews of Accelerator Science and Technology. y 2 Electron beam-based sources of ultrashort x-ray pulses * Alexander Zholents Argonne National Laboratory, Advanced Photon Source, 9700 South Cass Ave., Argonne, IL 60439 Abstract 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. Introduction The importance of the time-resolved studies of matter at picosecond (ps),

365

Fast ignition of fusion targets by laser-driven electrons  

E-Print Network (OSTI)

We present hybrid PIC simulations of fast electron transport and energy deposition in pre-compressed fusion targets, taking full account of collective magnetic effects and the hydrodynamic response of the background plasma. Results on actual ignition of an imploded fast ignition configuration are shown accounting for the increased beam divergence found in recent experiments [J.S. Green et al., Phys. Rev. Lett. 100, 015003 (2008)] and the reduction of the electron kinetic energy due to profile steepening predicted by advanced PIC simulations [B. Chrisman et al. Phys. Plasmas 15, 056309 (2008)]. Target ignition is studied as a function of injected electron energy, distance of cone-tip to dense core, initial divergence and kinetic energy of the relativistic electron beam. We found that beam collimation reduces substantially the ignition energies of the cone-guided fuel configuration assumed here.

Honrubia, J J

2008-01-01T23:59:59.000Z

366

Broadband Single-Shot Electron Spectrometer for GeV-Class Laser Plasma Based Accelerators  

E-Print Network (OSTI)

of the 2007 Particle Accelerator Conference, p. 2978,Class Laser Plasma Based Accelerators K. Nakamura, ? W. Wan,Laser-plasma-based accelerators can provide electrons over a

Nakamura, K.

2008-01-01T23:59:59.000Z

367

Laser beam self-symmetrization in air in the multifilamentation regime  

E-Print Network (OSTI)

We show experimental and numerical evidence of spontaneous self-symmetrization of focused laser beams experiencing multi-filamentation in air. The symmetrization effect is observed as the multiple filaments generated prior to focus approach the focal volume. This phenomenon is attributed to the nonlinear interactions amongst the different parts of the beam mediated by the optical Kerr effect, which leads to a symmetric redistribution of the wave vectors even when the beam consists of a bundle of many filaments.

Milian, Carles; Couairon, Arnaud; Houard, Aurelien; Forestier, Benjamin; Carbonnel, Jerome; Liu, Yi; Prade, Bernard; Mysyrowicz, Andre

2015-01-01T23:59:59.000Z

368

Laser-Cooled Lithium Atoms: A New Source for Focused Ion Beams  

E-Print Network (OSTI)

Laser-Cooled Lithium Atoms: A New Source for Focused Ion Beams P R O J E C T L E A D E R : Jabez Mc) to provide ions for a focused ion beam (FIB) capable of non-destructive imaging. K E Y A C C O M P L I S H M mounted on a commercial focused ion beam system, creating the world's first lithium ion microscope

369

Cooperative effect of ultraviolet and near-infrared beams in laser-induced condensation  

SciTech Connect

We demonstrate the cooperative effect of near infrared (NIR) and ultraviolet (UV) beams on laser-induced condensation. Launching a UV laser after a NIR pulse yields up to a 5-fold increase in the production of nanoparticles (25300 nm) as compared to a single NIR beam. This cooperative effect exceeds the sum of those from the individual beams and occurs for delays up to 1 ?s. We attribute it to the UV photolysis of ozone created by the NIR pulses. The resulting OH radicals oxidize NO{sub 2} and volatile organic compounds, producing condensable species.

Matthews, M.; Henin, S.; Pomel, F.; Kasparian, J.; Wolf, J.-P. [Universit de Genve, GAP-Biophotonics, Chemin de Pinchat 22, 1211 Geneva 4 (Switzerland)] [Universit de Genve, GAP-Biophotonics, Chemin de Pinchat 22, 1211 Geneva 4 (Switzerland); Thberge, F.; Daigle, J.-F. [Defence R and D Canada Valcartier, 2459 de la Bravoure Blvd., Quebec (Qc) G3J 1X5 (Canada)] [Defence R and D Canada Valcartier, 2459 de la Bravoure Blvd., Quebec (Qc) G3J 1X5 (Canada); Lassonde, P.; Kieffer, J.-C. [INRS-EMT, 1650 Lionel Boulet Blvd., Varennes, Quebec (Qc) J3X1S2 (Canada)] [INRS-EMT, 1650 Lionel Boulet Blvd., Varennes, Quebec (Qc) J3X1S2 (Canada)

2013-12-23T23:59:59.000Z

370

Ultrafast molecular imaging by laser-induced electron diffraction  

SciTech Connect

We address the feasibility of imaging geometric and orbital structures of a polyatomic molecule on an attosecond time scale using the laser-induced electron diffraction (LIED) technique. We present numerical results for the highest molecular orbitals of the CO{sub 2} molecule excited by a near-infrared few-cycle laser pulse. The molecular geometry (bond lengths) is determined within 3% of accuracy from a diffraction pattern which also reflects the nodal properties of the initial molecular orbital. Robustness of the structure determination is discussed with respect to vibrational and rotational motions with a complete interpretation of the laser-induced mechanisms.

Peters, M. [Universite Paris-Sud, Institut des Sciences Moleculaires d'Orsay (CNRS), F-91405 Orsay (France); Departement de Chimie, Universite Laval, Quebec, Quebec G1K 7P4 (Canada); Nguyen-Dang, T. T. [Departement de Chimie, Universite Laval, Quebec, Quebec G1K 7P4 (Canada); Cornaggia, C. [CEA IRAMIS, SPAM, Saclay, Batiment 522, F-91191 Gif-sur-Yvette (France); Saugout, S.; Charron, E.; Keller, A.; Atabek, O. [Universite Paris-Sud, Institut des Sciences Moleculaires d'Orsay (CNRS), F-91405 Orsay (France)

2011-05-15T23:59:59.000Z

371

Optical measurements on the Boeing free electron laser ring resonator experiment  

Science Journals Connector (OSTI)

The Boeing free electron laser is presently operating with a stable semiconfocal ring optical cavity surrounding a 5 m wiggler. The resonator consists of two grazing-incidence reflective telescopes each formed by a grazing-incidence hyperboloid and its companion off-axis paraboloid. The resonator is closed by two flats: one used for dynamic jitter correction and the other used to outcouple some of the circulating beam. It is critical to lasing that the alignment of the resonator be maintained, the focus of the optical mode be at the midpoint of the wiggler, and the wavefront quality of the propagating beam be maintained. Measurements of the focus position, power loss, and wavefront quality are made before operation of the electron accelerator to diagnose whether the conditions required for lasing exist.

M.L. Laucks; D.H. Dowell; A.R. Lowrey; M. Bemes; A. Currie; P. Johnson; K. McCrary; J. Adamski; D. Pistoresi; D.R. Shoffstall; M. Bentz; R. Burns; R. Hudyma; K. Sun; W. Mower; S. Bender; J. Goldstein; A. Lumpkin; B. McVey; R. Tokar; D. Shemwell

1991-01-01T23:59:59.000Z

372

Collisionless absorption, hot electron generation, and energy scaling in intense laser-target interaction  

E-Print Network (OSTI)

Among the various attempts to understand collisionless absorption of intense ultrashort laser pulses a variety of models has been invented to describe the laser beam target interaction. In terms of basic physics collisionless absorption is understood now as the interplay of the oscillating laser field with the space charge field produced in the plasma. A first approach to this idea is realized in Brunel's model the essence of which consists in the formation of an oscillating charge cloud in the vacuum in front of the target. The investigation of statistical ensembles of orbits shows that the absorption process is localized at the ion-vacuum interface and in the skin layer: Single electrons enter into resonance with the laser field thereby undergoing a phase shift which causes orbit crossing and braking of Brunel's laminar flow. This anharmonic resonance acts like an attractor for the electrons and leads to the formation of a Maxwellian tail in the electron energy spectrum. Most remarkable results of our inves...

Liseykina, T; Murakami, M

2014-01-01T23:59:59.000Z

373

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

Science Journals Connector (OSTI)

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

R. Brinkmann; Y. Derbenev; K. Flttmann

2001-05-18T23:59:59.000Z

374

Increasing the upper-limit intensity and temperature range for thermal self-focusing of a laser beam by using plasma density ramp-up  

SciTech Connect

This work is devoted to improving relativistic and ponderomotive thermal self-focusing of the intense laser beam in an underdense plasma. It is shown that the ponderomotive nonlinearity induces a saturation mechanism for thermal self-focusing. Therefore, in addition to the well-known lower-limit critical intensity, there is an upper-limit intensity for thermal self-focusing above which the laser beam starts to experience ponderomotive defocusing. It is indicated that the upper-limit intensity value is dependent on plasma and laser parameters such as the plasma electron temperature, plasma density, and laser spot size. Furthermore, the effect of the upward plasma density ramp profile on the thermal self-focusing is studied. Results show that by using the plasma density ramp-up, the upper-limit intensity increases and the self-focusing temperature range expands.

Bokaei, B.; Niknam, A. R., E-mail: a-niknam@sbu.ac.ir [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran (Iran, Islamic Republic of)

2014-03-15T23:59:59.000Z

375

Rescattering effects in laser-assisted electron-atom bremsstrahlung  

E-Print Network (OSTI)

Rescattering effects in nonresonant spontaneous laser-assisted electron-atom bremsstrahlung (LABrS) are analyzed within the framework of time-dependent effective-range (TDER) theory. It is shown that high energy LABrS spectra exhibit rescattering plateau structures that are similar to those that are well-known in strong field laser-induced processes as well as those that have been predicted theoretically in laser-assisted collision processes. In the limit of a low-frequency laser field, an analytic description of LABrS is obtained from a rigorous quantum analysis of the exact TDER results for the LABrS amplitude. This amplitude is represented as a sum of factorized terms involving three factors, each having a clear physical meaning. The first two factors are the exact field-free amplitudes for electron-atom bremsstrahlung and for electron-atom scattering, and the third factor describes free electron motion in the laser field along a closed trajectory between the first (scattering) and second (rescattering) co...

Zheltukhin, A N; Frolov, M V; Manakov, N L; Starace, Anthony F

2015-01-01T23:59:59.000Z

376

Laser fusion neutron source employing compression with short pulse lasers  

DOE Patents (OSTI)

A method and system for achieving fusion is provided. The method includes providing laser source that generates a laser beam and a target that includes a capsule embedded in the target and filled with DT gas. The laser beam is directed at the target. The laser beam helps create an electron beam within the target. The electron beam heats the capsule, the DT gas, and the area surrounding the capsule. At a certain point equilibrium is reached. At the equilibrium point, the capsule implodes and generates enough pressure on the DT gas to ignite the DT gas and fuse the DT gas nuclei.

Sefcik, Joseph A; Wilks, Scott C

2013-11-05T23:59:59.000Z

377

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

SciTech Connect

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

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

2011-03-15T23:59:59.000Z

378

Electron microscopy of GaAs/AlGaAs quantum cascade laser  

Science Journals Connector (OSTI)

The quantum cascade laser (QCL) is based on a different principle comparing to bipolar semiconductor lasers, because it uses only one type of ... electrons and therefore is called an unipolar laser.

A. ?aszcz; J. Ratajczak; A. Czerwinski

2008-01-01T23:59:59.000Z

379

EBIT (Electron Beam Ion Trap), N-Division Experimental Physics. Annual report, 1994  

SciTech Connect

The experimental groups in the Electron Beam Ion Trap (EBIT) program continue to perform front-line research with trapped and extracted highly charged ions (HCI) in the areas of ion/surface interactions, atomic spectroscopy, electron-ion interaction and structure measurements, highly charged ion confinement, and EBIT development studies. The ion surface/interaction studies which were initiated five years ago have reached a stage where they an carry out routine investigations, as well as produce breakthrough results towards the development of novel nanotechnology. At EBIT and SuperEBIT studies of the x-ray emission from trapped ions continue to produce significant atomic structure data with high precision for few electron systems of high-Z ions. Furthermore, diagnostics development for magnetic and laser fusion, supporting research for the x-ray laser and weapons programs, and laboratory astrophysics experiments in support of NASA`s astrophysics program are a continuing effort. The two-electron contributions to the binding energy of helium like ions were measured for the first time. The results are significant because their precision is an order of magnitude better than those of competing measurements at accelerators, and the novel technique isolates the energy corrections that are the most interesting. The RETRAP project which was initiated three years ago has reached a stage where trapping, confining and electronic cooling of HCI ions up to Th{sup 80+} can be performed routinely. Measurements of the rates and cross sections for electron transfer from H{sub 2} performed to determine the lifetime of HCI up to Xe{sup q+} and Th{sup q+} (35 {le} q {le} 80) have been studied at mean energies estimated to be {approximately} 5 q eV. This combination of heavy ions with very high charges and very low energies is rare in nature, but may be encountered in planned fusion energy demonstration devices, in highly charged ion sources, or in certain astrophysical events.

Schneider, D. [ed.

1995-10-01T23:59:59.000Z

380

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

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

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

Note: This page contains sample records for the topic "lasers electron beams" 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.


381

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

Science Journals Connector (OSTI)

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

V. A. Burdovitsin; Yu. A. Burachevskii

2003-03-01T23:59:59.000Z

382

Air fluorescence measurements in the spectral range 300-420 nm using a 28.5 GeV electron beam  

E-Print Network (OSTI)

Measurements are reported of the yield and spectrum of fluorescence, excited by a 28.5 GeV electron beam, in air at a range of pressures of interest to ultra-high energy cosmic ray detectors. The wavelength range was 300 - 420 nm. System calibration has been performed using Rayleigh scattering of a nitrogen laser beam. In atmospheric pressure dry air at 304 K the yield is 20.8 +/- 1.6 photons per MeV.

R. Abbasi; T. Abu-Zayyad; K. Belov; J. Belz; Z. Cao; M. Dalton; Y. Fedorova; P. Huentemeyer; B. F. Jones; C. C. H. Jui; E. C. Loh; N. Manago; K. Martens; J. N. Matthews; M. Maestas; J. Smith; P. Sokolsky; R. W. Springer; J. Thomas; S. Thomas; P. Chen; C. Field; C. Hast; R. Iverson; J. S. T. Ng; A. Odian; K. Reil; D. Walz; D. R. Bergman; G. Thomson; A. Zech; F-Y. Chang; C-C. Chen; C-W. Chen; M. A. Huang; W-Y. P. Hwang; G-L. Lin

2007-08-23T23:59:59.000Z

383

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

E-Print Network (OSTI)

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

Anlage, Steven

384

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

E-Print Network (OSTI)

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

Caspers, Friedhelm; Scandale, Walter; Zimmermann, F

2009-01-01T23:59:59.000Z

385

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

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

line to match... -power electromagnetic radiation and high- brightness electron beams, including laser acceleration of electrons and Free... transport lines to match the...

386

E-Print Network 3.0 - alamos free-electron laser Sample Search...  

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

free-electron laser Search Powered by Explorit Topic List Advanced Search Sample search results for: alamos free-electron laser Page: << < 1 2 3 4 5 > >> 1 Applications: Medical...

387

E-Print Network 3.0 - axial free-electron laser Sample Search...  

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

free-electron laser Search Powered by Explorit Topic List Advanced Search Sample search results for: axial free-electron laser Page: << < 1 2 3 4 5 > >> 1 JOURNAL DE PHYSIQUE...

388

George Neil Named to Lead JLab's Free-Electron Laser Program...  

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

George Neil Named to Lead JLab's Free-Electron Laser Program NEWPORT NEWS, Va., Feb.15, 2008 - Dr. George Neil has been named Associate Director of the Free-Electron Laser Division...

389

Free-electron laser scientist is one of two newly elected American...  

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

Steve Benson Steve Benson of the Free-Electron Laser (FEL) group was recently selected as a 2002 Fellow of the American Physical Society Free-electron laser scientist is one of two...

390

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

SciTech Connect

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

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

2013-01-01T23:59:59.000Z

391

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

SciTech Connect

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

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

2014-05-15T23:59:59.000Z

392

Laser photons acquire circular polarization by interacting with a Dirac or Majorana neutrino beam  

E-Print Network (OSTI)

It is shown that for the reason of neutrinos being left-handed and their gauge-couplings being parity-violated, linearly polarized photons acquire their circular polarization by interacting with neutrinos. Calculating the ratio of linear and circular polarizations of laser photons interacting with either Dirac or Majorana neutrino beam, we obtain this ratio for the Dirac neutrino case, which is about twice less than the ratio for the Majorana neutrino case. Based on this ratio, we discuss the possibility of using advanced laser facilities and the T2K neutrino experiment to measure the circular polarization of laser beams interacting with neutrino beams in ground laboratories. This could be an additional and useful way to gain some insight into the physics of neutrinos, for instance their Dirac or Majorana nature.

Rohoollah Mohammadi; She-Sheng Xue

2014-03-14T23:59:59.000Z

393

Transverse pulse shaping and optimization of a tapered hard X-ray free electron laser  

E-Print Network (OSTI)

Multidimensional optimization schemes for TW hard X-Ray free electron lasers are applied to the cases of transversely uniform and parabolic electron beam distributions and compared to examples of transversely Gaussian beams. The optimizations are performed for a $200$m undulator and a resonant wavelength of $\\lambda_r=1.5\\AA $ using the fully 3-dimensional FEL particle code GENESIS. Time dependent simulations showed that the maximum radiation power is larger for flatter transverse distributions due to enhanced optical guiding in the tapered section of the undulator. For a transversely Gaussian beam the maximum output power was found to be $\\text{P}_{max}$=$1.56$ TW compared to $2.26$ TW for the parabolic case and $2.63$ TW for the uniform case. Spectral data also showed a 30-70$\\%$ reduction in energy deposited in the sidebands for the uniform and parabolic beams compared with a Gaussian. An analysis of the maximum power as a function of detuning from resonance shows that redshifting the central wavelength by...

Emma, Claudio; Wu, Juhao

2014-01-01T23:59:59.000Z

394

Active beam position stabilization of pulsed lasers for long-distance ion profile diagnostics at the Spallation Neutron Source (SNS)  

SciTech Connect

A high peak-power Q-switched laser has been used to monitor the ion beam profiles in the superconducting linac at the Spallation Neutron Source (SNS). The laser beam suffers from position drift due to movement, vibration, or thermal effects on the optical components in the 250-meter long laser beam transport line. We have designed, bench-tested, and implemented a beam position stabilization system by using an Ethernet CMOS camera, computer image processing and analysis, and a piezo-driven mirror platform. The system can respond at frequencies up to 30 Hz with a high position detection accuracy. With the beam stabilization system, we have achieved a laser beam pointing stability within a range of 2 rad (horizontal) to 4 rad (vertical), corresponding to beam drifts of only 0.5 mm 1 mm at the furthest measurement station located 250 meters away from the light source.

Hardin, Robert A [ORNL; Liu, Yun [ORNL; Long, Cary D [ORNL; Aleksandrov, Alexander V [ORNL; Blokland, Willem [ORNL

2011-01-01T23:59:59.000Z

395

Femtosecond diffractive imaging with a soft-X-ray free-electron laser  

E-Print Network (OSTI)

LETTERS Femtosecond diffractive imaging with a soft-X-ray free-electron laser HENRY N. CHAPMAN1 of this principle using the FLASH soft-X-ray free-electron laser. An intense 25 fs, 4 ? 1013 W cm-2 pulse by one10 . X-ray free-electron lasers (FELs) are expected to permit diffractive imaging at high

Loss, Daniel

396

Reflector for efficient coupling of a laser beam to air or other fluids  

DOE Patents (OSTI)

A reflector array is disclosed herein that provides a controlled region or regions of plasma breakdowns from a laser beam produced at a remotely-based laser source. The plasma may be applied to produce thrust to propel a spacecraft, or to diagnose a laser beam, or to produce shockwaves. The spacecraft propulsion system comprises a reflector array attached to the vehicle. The reflector array comprises a plurality of reflectors spaced apart on a reflective surface, with each reflector acting as an independent focusing mirror. The reflectors are spaced closely together to form a continuous or partially-continuous surface. The reflector array may be formed from a sheet of reflective material, such as copper or aluminum. In operation, a beam of electromagnetic energy, such as a laser beam, is directed at the reflectors which focus the reflected electromagnetic energy at a plurality of regions off the surface. The energy concentrated in the focal region causes a breakdown of the air or other fluid in the focal region, creating a plasma. Electromagnetic energy is absorbed in the plasma and it grows in volume, compressing and heating the adjacent fluid thereby providing thrust. Laser pulses may be applied repetitively. After each such thrust pulse, fresh air can be introduced next to the surface either laterally, or through a perforated surface. If air or some other gas or vapor is supplied, for example from a tank carried on board a vehicle, this invention may also be used to provide thrust in a vacuum environment.

Kare, Jordin T. (Pleasanton, CA)

1992-01-01T23:59:59.000Z

397

Reflector for efficient coupling of a laser beam to air or other fluids  

DOE Patents (OSTI)

A reflector array is disclosed herein that provides a controlled region or regions of plasma breakdowns from a laser beam produced at a remotely-based laser source. The plasma may be applied to produce thrust to propel a spacecraft, or to diagnose a laser beam, or to produce shock waves. The spacecraft propulsion system comprises a reflector array attached to the vehicle. The reflector array comprises a plurality of reflectors spaced apart on a reflective surface, with each reflector acting as an independent focusing mirror. The reflectors are spaced closely together to form a continuous or partially-continuous surface. The reflector array may be formed from a sheet of reflective material, such as copper or aluminum. In operation, a beam of electromagnetic energy, such as a laser beam, is directed at the reflectors which focus the reflected electromagnetic energy at a plurality of regions off the surface. The energy concentrated in the focal region causes a breakdown of the air or other fluid in the focal region, creating a plasma. Electromagnetic energy is absorbed in the plasma and it grows in volume, compressing and heating the adjacent fluid thereby providing thrust. Laser pulses may be applied repetitively. After each such thrust pulse, fresh air can be introduced next to the surface either laterally, or through a perforated surface. If air or some other gas or vapor is supplied, for example from a tank carried on board a vehicle, this invention may also be used to provide thrust in a vacuum environment. 10 figs.

Kare, J.T.

1992-10-06T23:59:59.000Z

398

Laser power beaming to extend lives of GSO NiCd satellites  

SciTech Connect

It is proposed that a ground-based laser can beam power to commercial communication satellites in geosynchronous orbit and reduce battery depth-of-discharge during eclipses. Two laser system designs are presented which have the capability of reducing battery discharge by 100%. Both utilize a steerable beam director, with a mirror diameter of 4 meters in one case and 8 meters in the other. Both also use an adaptive optics unit within the beam train to provide real-time corrections for wavefront distortions caused by atmospheric turbulence. The required system power output is in the range of 100 to 200 kW for a transmitted wavelength just under 900 nm. Laser power beaming can nearly double the remaining lifetime of a satellite that uses NiCd batteries. However, by the time such lasers become available, nearly all NiCd satellites will be replaced by NiH{sub 2} satellites, which stand to benefit much less from power beaming.

Monroe, D.K.

1993-12-31T23:59:59.000Z

399

Efficiency enhancement in a single-pass Raman free electron laser  

SciTech Connect

Efficiency enhancement in free electron laser (FEL) with ion channel and axial magnetic field is compared. By using Maxwell's equations and nonwiggler averaged equation of motion of electron beam, a set of coupled nonlinear differential equations is derived in the slowly varying amplitude and wave number approximation. Because of using nonwiggler averaged equation of motion, it is possible to treat the injection of the beam into the wiggler. The electron beam propagates with a relativistic velocity, ions are assumed immobile and slippage is ignored. The final set of nonlinear first-order differential equations describing the nonlinear evolution of the FEL is solved by the Runge-Kutta method. Efficiency enhancement in group I orbits is almost the same for both ion channel and axial magnetic field cases, with somewhat larger growth rate for the latter. In group II orbits, efficiency enhancement is not possible for the ion-channel guiding; however, the intrinsic efficiency can be larger than that of the axial magnetic field case.

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

2009-09-15T23:59:59.000Z

400

Normal Conducting CW RF Gun Design for High Performance Electron Beams  

SciTech Connect

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

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

2008-07-01T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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

High power gas laser amplifier  

DOE Patents (OSTI)

A high power output CO.sub.2 gas laser amplifier having a number of sections, each comprising a plurality of annular pumping chambers spaced around the circumference of a vacuum chamber containing a cold cathode, gridded electron gun. The electron beam from the electron gun ionizes the gas lasing medium in the sections. An input laser beam is split into a plurality of annular beams, each passing through the sections comprising one pumping chamber.

Leland, Wallace T. (Los Alamos, NM); Stratton, Thomas F. (Los Alamos, NM)

1981-01-01T23:59:59.000Z

402

Fluorescence from CsF ionic excimers excited by an electron beam  

SciTech Connect

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

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

1992-08-01T23:59:59.000Z

403

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

SciTech Connect

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

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

2012-02-15T23:59:59.000Z

404

Fracture Behavior of a Laser Beam Welded High-strength Al-Zn Alloy  

Science Journals Connector (OSTI)

Abstract Laser beam welding of butt joints made of the newly developed high-strength Al-Zn alloy PA734 is conducted. A new approach of the Helmholtz-Zentrum Geesthacht is used to solve the problems of weldability and softening. The results of the fatigue, fatigue crack propagation and fracture toughness tests are discussed relating to the microstructural characteristics and the mechanical properties of the laser welded joints and compared to the base material. The obtained data can be used for the assessment of the damage tolerance behaviour of the laser welded integral aircraft structures made of Al-Zn alloys.

J. Enz; H. Iwan; S. Riekehr; V. Ventzke; N. Kashaev

2014-01-01T23:59:59.000Z

405

Generation of periodic ultrashort electron bunches and strongly asymmetric ion Coulomb explosion in nanometer foils interacting with ultra-intense laser pulse  

SciTech Connect

The interaction of a linearly polarized intense laser pulse with an ultrathin nanometer plasma layer is investigated to understand the physics of the ion acceleration. It is shown by the computer simulation that the plasma response to the laser pulse comprises two steps. First, due to the vxB effect, electrons in the plasma layer are extracted and periodic ultrashort relativistic electron bunches are generated every half of a laser period. Second, strongly asymmetric Coulomb explosion of ions in the foil occurs due to the strong electrostatic charge separation, once the foil is burnt through. Followed by the laser accelerated electron bunch, the ion expansion in the forward direction occurs along the laser beam that is much stronger as compared to the backward direction.

Tian Youwei [College of Mathematics and Physics, Nanjing University of Posts and Telecommunications, Nanjing 210003 (China); Yu Wei; Xu Han; Lei Anle; Shen Baifei; Wang Xin [State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800 (China); Lu Peixiang [State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan 430070 (China); Senecha, Vinod [Raja Ramanna Centre for Advanced Technology, Indore-452 013 (India)

2008-05-15T23:59:59.000Z

406

Lucretia: A Matlab-Based Toolbox for the Modellingand Simulation of Single-Pass Electron Beam Transport Systems  

SciTech Connect

We report on Lucretia, a new simulation tool for the study of single-pass electron beam transport systems. Lucretia supports a combination of analytic and tracking techniques to model the tuning and operation of bunch compressors, linear accelerators, and beam delivery systems of linear colliders and linac-driven Free Electron Laser (FEL) facilities. Extensive use of Matlab scripting, graphics, and numerical capabilities maximize the flexibility of the system, and emphasis has been placed on representing and preserving the fixed relationships between elements (common girders, power supplies, etc.) which must be respected in the design of tuning algorithms. An overview of the code organization, some simple examples, and plans for future development are discussed.

Tenenbaum, P.; /SLAC

2005-09-30T23:59:59.000Z

407

Effects of powder feeding rate on interaction between laser beam and powder streamin laser cladding process  

Science Journals Connector (OSTI)

A theoretical model was presented to calculate the laser intensity distribution and the particle temperatures at different sites of the workpiece in the laser cladding process. By using this model, the ... effect...

Huang Yan-lu; Li Jian-guo; Liang Gong-ying

2004-12-01T23:59:59.000Z

408

Gamma-ray free-electron lasers: Quantum fluid model  

E-Print Network (OSTI)

A quantum fluid model is used to describe the interacion of a nondegenerate cold relativistic electron beam with an intense optical wiggler taking into account the beam space-charge potential and photon recoil effect. A nonlinear set of coupled equations are obtained and solved numerically. The numerical results shows that in the limit of plasma wave-breaking an ultra-high power radiation pulse are emitted at the$\\gamma$-ray wavelength range which can reach an output intensity near the Schwinger limit depending of the values of the FEL parameters such as detuning and input signal initial phase at the entrance of the interaction region.

Silva, H M

2014-01-01T23:59:59.000Z

409

XTREME OPTICS: the behavior of cavity optics for the Jefferson Lab free-electron laser  

SciTech Connect

The cavity optics within high power free-electron lasers based on energy-recovering accelerators are subjected to extreme conditions associated with illumination from a broad spectrum of radiation, often at high irradiances. This is especially true for the output coupler, where absorption of radiation by both the mirror substrate and coating places significant design restrictions to properly manage heat load and prevent mirror distortion. Besides the fundamental lasing wavelength, the mirrors are irradiated with light at harmonics of the fundamental, THz radiation generated by the bending magnets downstream of the wiggler, and x-rays produced when the electron beam strikes accelerator diagnostic components (e.g., wire scanners and view screens) or from inadvertent beam loss. The optics must reside within high vacuum at ~ 10-8 Torr and this requirement introduces its own set of complications. This talk discusses the performance of numerous high reflector and output coupler optics assemblies and provides a detailed list of lessons learned gleaned from years of experience operating the Upgrade IR FEL, a 10 kW-class, sub-ps laser with output wavelength from 1 to 6 microns.

Michelle D. Shinn; Christopher Behre; Stephen Benson; David Douglas; Fred Dylla; Christopher Gould; Joseph Gubeli; David Hardy; Kevin Jordan; George Neil; and Shukui Zhanga

2006-09-25T23:59:59.000Z

410

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

411

An Optimized Nanoparticle Separator Enabled by Electron Beam Induced Deposition  

SciTech Connect

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

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

2010-01-01T23:59:59.000Z

412

Beam steering via resonance detuning in coherently coupled vertical cavity laser arrays  

SciTech Connect

Coherently coupled vertical-cavity surface-emitting laser arrays offer unique advantages for nonmechanical beam steering applications. We have applied dynamic coupled mode theory to show that the observed temporal phase shift between vertical-cavity surface-emitting array elements is caused by the detuning of their resonant wavelengths. Hence, a complete theoretical connection between the differential current injection into array elements and the beam steering direction has been established. It is found to be a fundamentally unique beam-steering mechanism with distinct advantages in efficiency, compactness, speed, and phase-sensitivity to current.

Johnson, Matthew T., E-mail: matthew.johnson.9@us.af.mil; Siriani, Dominic F.; Peun Tan, Meng; Choquette, Kent D. [Department of Electrical and Computer Engineering University of Illinois, Urbana, Illinois 61820 (United States)] [Department of Electrical and Computer Engineering University of Illinois, Urbana, Illinois 61820 (United States)

2013-11-11T23:59:59.000Z

413

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

Science Journals Connector (OSTI)

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

Katsuhisa Murakami; Mikio Takai

2015-01-01T23:59:59.000Z

414

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

SciTech Connect

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

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

2011-06-17T23:59:59.000Z

415

Laser Micromachining and Information Discovery Using a Dual Beam Interferometry  

SciTech Connect

Lasers have proven to be among the most promising tools for micromachining because they can process features down to the size of the laser wavelength (smaller than 1 micrometer) and they provide a non-contact technology for machining. The demand for incorporating in-situ diagnostics technology into the micromachining environment is driven by the increasing need for producing micro-parts of high quality and accuracy. Laser interferometry can be used as an on-line monitoring tool and it is the aim of this work to enhance the understanding and application of Michelson interferometry principle for the in-situ diagnostics of the machining depth on the sub-micron and micron scales. micromachining is done on two different materials and a comprehensive investigation is done to control the width and depth of the machined feature. To control the width of the feature, laser micromachining is done on copper and a detailed analysis is performed. The objective of this experiment is to make a precision mask for sputtering with an array of holes on it using an Nd:YAG laser of 532 nm wavelength. The diameter of the hole is 50 {micro}m and the spacing between holes (the distance between the centers) is 100 {micro}m. Michelson interferometer is integrated with a laser machining system to control the depth of machining. An excimer laser of 308 nm wavelength is used for micromachining. A He-Ne laser of 632.8 nm wavelength is used as the light source for the interferometer. Interference patterns are created due to the change in the path length between the two interferometer arms. The machined depth information is obtained from the interference patterns on an oscilloscope detected by a photodiode. To compare the predicted depth by the interferometer with the true machining depth, a surface profilometer is used to measure the actual machining depth on the silicon. It is observed that the depths of machining obtained by the surface profile measurement are in accordance with the interferometer measurements with a very high accuracy. The experimental results demonstrate the feasibility of applying this system in industries that require precise measurements where cost of making as well as accuracy both cannot be compromised.

Senthil P. Theppakuttaikomaraswamy

2001-12-31T23:59:59.000Z

416

Study of electron acceleration and x-ray radiation as a function of plasma density in capillary-guided laser wakefield accelerators  

SciTech Connect

Laser wakefield electron acceleration in the blow-out regime and the associated betatron X-ray radiation were investigated experimentally as a function of the plasma density in a configuration where the laser is guided. Dielectric capillary tubes were employed to assist the laser keeping self-focused over a long distance by collecting the laser energy around its central focal spot. With a 40 fs, 16 TW pulsed laser, electron bunches with tens of pC charge were measured to be accelerated to an energy up to 300 MeV, accompanied by X-ray emission with a peak brightness of the order of 10{sup 21} ph/s/mm{sup 2}/mrad{sup 2}/0.1%BW. Electron trapping and acceleration were studied using the emitted X-ray beam distribution to map the acceleration process; the number of betatron oscillations performed by the electrons was inferred from the correlation between measured X-ray fluence and beam charge. A study of the stability of electron and X-ray generation suggests that the fluctuation of X-ray emission can be reduced by stabilizing the beam charge. The experimental results are in good agreement with 3D particle-in-cell (PIC) simulation.

Ju, J.; Dpp, A.; Cros, B. [Laboratoire de Physique des Gaz et des Plasmas, CNRS-Universit Paris-Sud, 91405 Orsay (France)] [Laboratoire de Physique des Gaz et des Plasmas, CNRS-Universit Paris-Sud, 91405 Orsay (France); Svensson, K.; Genoud, G.; Wojda, F.; Burza, M.; Persson, A.; Lundh, O.; Wahlstrm, C.-G. [Department of Physics, Lund University, P.O. Box 118, S-22100 Lund (Sweden)] [Department of Physics, Lund University, P.O. Box 118, S-22100 Lund (Sweden); Ferrari, H. [Consejo Nacional de Investigaciones Cientficas y Tcnicas (CONICET) and CNEA-CAB (Argentina)] [Consejo Nacional de Investigaciones Cientficas y Tcnicas (CONICET) and CNEA-CAB (Argentina)

2013-08-15T23:59:59.000Z

417

ANL/TD/TM03-01: Lasers and Beam Delivery for Rock Drilling  

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

Development ANL/TD/TM03-01 Development ANL/TD/TM03-01 Division Technology Development Division Technology Development Division Technology Development Division Technology Development Lasers and Beam Delivery for Division Rock Drilling Technology Development Division Technology Development Division by Technology Development K.H. Leong, Z. Xu, C.B. Reed, and Division R.A. Parker Technology Development Division

418

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

Science Journals Connector (OSTI)

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

M. S. Lubell

1980-01-01T23:59:59.000Z

419

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

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

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

420

Strong extinction of a laser beam by a single molecule  

E-Print Network (OSTI)

We present an experiment where a single molecule strongly affects the amplitude and phase of a laser field emerging from a subwavelength aperture. We achieve a visibility of -6% in direct and +10% in cross-polarized detection schemes. Our analysis shows that a close to full extinction should be possible using near-field excitation.

I. Gerhardt; G. Wrigge; P. Bushev; G. Zumofen; R. Pfab; V. Sandoghdar

2006-04-24T23:59:59.000Z

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


421

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

Science Journals Connector (OSTI)

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

N.K. Neog; S.R. Mohanty

2007-01-01T23:59:59.000Z

422

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

SciTech Connect

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

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

2013-11-07T23:59:59.000Z

423

Electron acceleration by a circularly polarized laser pulse in a plasma K. P. Singha)  

E-Print Network (OSTI)

Electron acceleration by a circularly polarized laser pulse in a plasma K. P. Singha) Department of electrons in an axial static field are presented. The electron rotates around the propagation direction occurs between the electrons and electric field of the laser pulse for two optimum values of the magnetic

Roy, Subrata

424

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

SciTech Connect

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

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

2009-09-15T23:59:59.000Z

425

On formation of a partially coherent beam in a stable-resonator laser  

SciTech Connect

A new method involving the expansion of the field coherence function in partially coherent modes - the eigensolutions of the problem for the second-order coherence function in a stable resonator - is proposed for the theoretical description of the process of multimode laser beam formation. The method for solving the problem for arbitrary partially coherent modes is formulated and the expressions for these modes are derived in the general form. The characteristics of the fundamental partially coherent mode, which coincides with the coherence function of a Gaussian partially coherent beam, are analysed in detail. The partially coherent modes are shown to possess two spatial scales - the effective radius and the coherence radius, which makes them a convenient tool for solving the problem of generation of a partially coherent beam. It is found that the unambiguous relation between the characteristics of partially coherent modes and the stable-resonator parameters is achieved by involving into consideration not only the process of the beam formation by the resonator mirrors but also the process of interaction of radiation with the active laser medium. (laser beams and resonators)

Suvorov, A A [State Scientific Center of the Russian Federation 'A.I. Leypunsky Institute for Physics and Power Engineering', Obninsk, Kaluga Region (Russian Federation)

2010-05-26T23:59:59.000Z

426

CP-violation reach of an electron capture neutrino beam  

E-Print Network (OSTI)

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

Christopher Orme

2010-07-12T23:59:59.000Z

427

Optimizing Laser-accelerated Ion Beams for a Collimated Neutron Source  

SciTech Connect

High-flux neutrons for imaging and materials analysis applications have typically been provided by accelerator- and reactor-based neutron sources. A novel approach is to use ultraintense (>1018W/cm2) lasers to generate picosecond, collimated neutrons from a dual target configuration. In this article, the production capabilities of present and upcoming laser facilities are estimated while independently maximizing neutron yields and minimizing beam divergence. A Monte-Carlo code calculates angular and energy distributions of neutrons generated by D-D fusion events occurring within a deuterated target for a given incident beam of D+ ions. Tailoring of the incident distribution via laser parameters and microlens focusing modifies the emerging neutrons. Projected neutron yields and distributions are compared to conventional sources, yielding comparable on-target fluxes per discharge, shorter time resolution, larger neutron energies and greater collimation.

C.L. Ellison and J. Fuchs

2010-09-23T23:59:59.000Z

428

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

SciTech Connect

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

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

2013-03-15T23:59:59.000Z

429

Ultrahigh-intensity optical slow-wave structure for direct laser electron acceleration  

E-Print Network (OSTI)

WAVEGUIDE Ultraintense laser­plasma interaction applications in- cluding x-ray lasers, coherentUltrahigh-intensity optical slow-wave structure for direct laser electron acceleration Andrew G of corrugated slow-wave plasma guiding structures with application to quasi- phase-matched direct laser

Milchberg, Howard

430

Free electron properties of metals under ultrafast laser-induced electron-phonon nonequilibrium: a first-principles study  

E-Print Network (OSTI)

Free electron properties of metals under ultrafast laser-induced electron-phonon nonequilibrium CEA-DIF, 91297 Arpajon, France (Dated: April 3, 2014) The electronic behavior of various solid metals modelled based on the free electron classical theory, the free electron number is a key parameter. However

Paris-Sud XI, Université de

431

Interaction between laser beam and powder stream in the process of laser cladding with powder feeding  

Science Journals Connector (OSTI)

Based on LambertBeer theorem and Mie's theory, the attenuation of laser power by a powder stream was calculated and the laser intensity distribution at the laser spot on the surface of a workpiece was obtained. Simultaneously, the temperature distribution of the powder particles arriving at different sites on the surface of the workpiece was computed following the heat equilibrium principle. The computed results revealed that for a given stream spread and speed of powder particles, the intensity distribution of the laser spot and the temperature distribution of the powder particles reaching the surface of the workpiece are both greatly affected by the powder feeding rate and the feeding angle. It is suggested that the presented results should be considered in the laser cladding process in order to control the dynamic processes in a laser molten pool.

Yan-Lu Huang; Gong-Ying Liang; Jun-Yi Su; Jian-Guo Li

2005-01-01T23:59:59.000Z

432

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

E-Print Network (OSTI)

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

433

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

SciTech Connect

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

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

2014-03-15T23:59:59.000Z

434

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

435

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

436

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

437

Tests of a grazing-incidence ring resonator free-electron laser  

SciTech Connect

This paper reports on the Boeing free-electron laser (FEL) optical cavity that has been changed from a simple concentric cavity using two spherical mirrors to a larger grazing-incidence ring resonator. The new resonator consists of two mirror telescopes located at each end of the wiggler with a round-trip path length of approximately 133 m. Each telescope is a grazing-incidence hyperboloid followed by a normal-incidence paraboloid. Initial tests showed that poorly positioned ring focus and unreliable pointing alignment resulted in reduced and structured FEL output. (First lasing operation occurred on March 23 and 24, 1990.) Later efforts concentrated on improving the resonator alignment techniques and lowering the single-pass losses. FEL performance and reliability have significantly improved due to better ring alignment. The alignment procedure and recent lasing results are described. The effect the electron beam has on lasing is also discussed. Measurements are presented showing how FEL temporal output and wavelength are sensitive to electron beam energy variations.

Dowell, D.H.; Laucks, M.L.; Lowrey, A.R.; Adamski, J.L.; Pistoresi, D.J.; Shoffstall, D.R. (Boeing Aerospace and Electronics, Seattle, WA (US)); Bentz, M.P.; Burns, R.H.; Guha, J.; Sun, K.; Tomita, W. (Rockwell International Corp., Canoga Park, CA (United States). Rocketdyne Div.); Lumpkin, A.H.; Bender, S.; Byrd, D.; Tokar, R.L. (Los Alamos National Lab., NM (United States))

1991-12-01T23:59:59.000Z

438

Quantitative experiments with electrons in a positively charged Beam  

E-Print Network (OSTI)

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

2006-01-01T23:59:59.000Z

439

Measurements and modeling of coherent synchrotron radiation and its impact on the Linac Coherent Light Source electron beam  

Science Journals Connector (OSTI)

In order to reach the high peak current required for an x-ray free electron laser, two separate magnetic dipole chicanes are used in the Linac Coherent Light Source accelerator to compress the electron bunch length in stages. In these bunch compressors, coherent synchrotron radiation (CSR) can be emitted either by a short electron bunch or by any longitudinal density modulation that may be on the bunch. In this paper, we report detailed measurements of the CSR-induced energy loss and transverse emittance growth in these compressors. Good agreement is found between the experimental results and multiparticle tracking studies. We also describe direct observations of CSR at optical wavelengths and compare with analytical models based on beam microbunching.

K. L. F. Bane; F.-J. Decker; Y. Ding; D. Dowell; P. Emma; J. Frisch; Z. Huang; R. Iverson; C. Limborg-Deprey; H. Loos; H.-D. Nuhn; D. Ratner; G. Stupakov; J. Turner; J. Welch; J. Wu

2009-03-17T23:59:59.000Z

440

Testing Thermo-acoustic Sound Generation in Water with Proton and Laser Beams  

E-Print Network (OSTI)

Experiments were performed at a proton accelerator and an infrared laser acility to investigate the sound generation caused by the energy deposition of pulsed particle and laser beams in water. The beams with an energy range of 1 PeV to 400 PeV per proton beam spill and up to 10 EeV for the laser pulse were dumped into a water volume and the resulting acoustic signals were recorded with pressure sensitive sensors. Measurements were performed at varying pulse energies, sensor positions, beam diameters and temperatures. The data is well described by simulations based on the thermo-acoustic model. This implies that the primary mechanism for sound generation by the energy deposition of particles propagating in water is the local heating of the media giving rise to an expansion or contraction of the medium resulting in a pressure pulse with bipolar shape. A possible application of this effect would be the acoustical detection of neutrinos with energies greater than 1 EeV.

K. Graf; G. Anton; J. Hoessl; A. Kappes; T. Karg; U. Katz; R. Lahmann; C. Naumann; K. Salomon; C. Stegmann

2005-09-15T23:59:59.000Z

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


441

Spectrum and conversion efficiency measurements of suprathermal electrons from relativistic laser plasma interactions  

E-Print Network (OSTI)

Fast Ignition is an alternative scheme for Inertial Confinement Fusion (ICF) that uses a petawatt laser to ignite a hot spot in precompressed fuel. The laser delivers its energy into relativistic electrons at the critical ...

Chen, Cliff D. (Cliff Ding Yu)

2009-01-01T23:59:59.000Z

442

A spatially and temporally localized sub-laser cycle electron source  

Science Journals Connector (OSTI)

We simulate electron emission from a sharp tungsten tip induced by sub-8fs laser pulses and compare DC field and laser power dependence of the emission with experimental results. The simulation shows that with...

Peter Hommelhoff; Catherine Kealhofer; Mark A. Kasevich

2007-01-01T23:59:59.000Z

443

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

SciTech Connect

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

Backfish, Michael

2013-04-01T23:59:59.000Z

444

Microwave beam steerers for electronically scanned reflectometers (abstract)  

SciTech Connect

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

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

1999-01-01T23:59:59.000Z

445

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

E-Print Network (OSTI)

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

446

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

E-Print Network (OSTI)

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

Jain, Neeraj; Palastro, J P

2014-01-01T23:59:59.000Z

447

Electron acceleration by a self-diverging intense laser pulse K. P. Singh,1,  

E-Print Network (OSTI)

Electron acceleration by a self-diverging intense laser pulse K. P. Singh,1, * D. N. Gupta,1 V. K, India 2 Department of Electronic Science, University of Delhi, New Delhi-110021, India (Received 23 October 2003; published 28 April 2004) Electron acceleration by a laser pulse having a Gaussian radial

Singh, Kunwar Pal

448

Quantum calculations of correlated electron-ion collisions in a strong laser field  

E-Print Network (OSTI)

Quantum calculations of correlated electron-ion collisions in a strong laser field G. Rascol, H September 2006; published online 31 October 2006 The energy spectrum and angular distribution of electrons scattered by an ion in a strong laser field are investigated as a function of the incident electron velocity

Kull, Hans-Jörg

449

X-Ray Entangled Photon Production in Collisions of Laser Beams with Relativistic Ions  

E-Print Network (OSTI)

A method is suggested to produce, with the help of colliding laser photons with bunches of relativistic ions having two energy levels, both intense beams of monochromatic polarized X-ray fluorescence photons and significant number of X-ray entangled photons, via double Doppler transformation. Nonlinear susceptibility of the ions, the cross section and the rate of production of such photons at RHIC are estimated. Such beams of X-ray photons can be detected and applied to solve various problems, in a manner similar to the usage of optical photons.

K. A. Ispirian; M. K. Ispiryan

2010-04-02T23:59:59.000Z

450

Proton beam on lithium film experiment for the FRIB stripper - Laser  

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

Engineering Engineering Experimentation > High Power Accelerator Components > Proton beam on lithium film experiment... Capabilities Engineering Experimentation Reactor Safety Testing and Analysis High Power Accelerator Components Proton beam on lithium film experiment for the FRIB stripper Aerosol Experiments System Components Laser Applications Robots Applications Other Facilities Other Capabilities Work with Argonne Contact us For Employees Site Map Help Join us on Facebook Follow us on Twitter NE on Flickr Proton beam on lithium film experiment for the FRIB stripper 1 2 Argonne National Laboratory has developed a liquid lithium charge stripper for use in the Facility for Rare Isotope Beams (FRIB) located at Michigan State University. FRIB will provide intense beams of rare isotopes that can not be handled by ordinary means, creating a challenge to find a workable concept for the charge stripper and to test it in a beamline environment. Argonne's experiment showed, for the first time, the operation of a liquid lithium stripper under realistic conditions of beam-deposited power, and verified that the liquid lithium film was not perturbed by a high power density beam.

451

Influence of nonparabolicity on electronic structure of quantum cascade laser  

Science Journals Connector (OSTI)

Abstract We analyze the influence of nonparabolicity on the bound electronic states in the conduction-band of quantum wells in external electric field. Numerical results, obtained by transfer matrix method are presented for active region of GaAs/Al0.3Ga0.7As quantum cascade laser. The structure was initially optimized by genetic algorithm, using Kane's model of nonparabolicity, with emission wavelength set to ? ? 15.1 ?m . However, our numerical results indicate the change in lasing wavelength to 14.04 ?m when using a more comprehensive description of nonparabolicity.

Nikola Vukovi?; Vitomir Milanovi?; Jelena Radovanovi?

2014-01-01T23:59:59.000Z

452

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

SciTech Connect

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

Hershcovitch,A.

2009-03-01T23:59:59.000Z

453

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

SciTech Connect

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

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

1990-07-01T23:59:59.000Z

454

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

SciTech Connect

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

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

2013-11-15T23:59:59.000Z

455

Measurement of the drift field in the ARGONTUBE LAr TPC with 266~nm pulsed laser beams  

E-Print Network (OSTI)

ARGONTUBE is a liquid argon time projection chamber (LAr TPC) with a drift field generated in-situ by a Greinacher voltage multiplier circuit. We present results on the measurement of the drift-field distribution inside ARGONTUBE using straight ionization tracks generated by an intense UV laser beam. Our analysis is based on a simplified model of the charging of a multi-stage Greinacher circuit to describe the voltages on the field cage rings.

A. Ereditato; D. Goeldi; S. Janos; I. Kreslo; M. Luethi; C. Rudolf von Rohr; M. Schenk; T. Strauss; M. S. Weber; M. Zeller

2014-10-30T23:59:59.000Z

456

Design considerations for the free-electron laser with the self...  

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

5 Design considerations for the free-electron laser with the self-seeding and current-enhanced SASE 1 Alexander Zholents Advanced Photon Source, Argonne National Laboratory...

457

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

E-Print Network (OSTI)

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

Eisenstein, Gadi

458

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

E-Print Network (OSTI)

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

459

Status of UCLA Helical Permanent-Magnet Inverse Free Electron Laser  

SciTech Connect

A helical undulator, utilizing permanent-magnet of cylindrically symmetric (Halbach) geometry is being developed at UCLA's Neptune Facility. The initial prototype is a short 10 cm, 7 periods long helical undulator, designed to test the electron-photon coupling by observing the micro-bunching is currently being constructed. The Neptune IFEL facility utilizes a 15 MeV Photoinjector-generated electron beam of 0.5 nC interacting with CO{sub 2} of peak energy up to 100 J, estimated to have acceleration of 100 MeV/m. An Open Iris-Loaded Waveguide Structure (OILS) scheme which conserves laser mode size and wave fronts throughout the undulator, is utilized to avoid Gouy phase shift caused by focusing of the drive laser. Undulator design was tested by computer simulations Radia and Genesis 1.3. Coherent Transition Radiation and Coherent Cherenkov Radiation will be used for micro-bunching diagnostic. Currently permanent dipoles and their aluminum holders have been built, and the project is in its final state of assembly and undulator testing.

Knyazik, A.; Tikhoplav, R.; Frederico, J. T.; Affolter, M.; Rosenzweig, J. B. [Department of Physics and Astronomy, UCLA, Los Angeles, California 90095 (United States)

2009-01-22T23:59:59.000Z

460

CO{sub 2} laser beam welding of magnesium-based alloys  

SciTech Connect

Magnesium has gained increased attention in recent years as a structural metal--especially in the automotive industry--necessitating the development of welding techniques qualified for this new application. Lasers are known to be an excellent tool for joining metals. This paper presents results of recent investigations on the weldability of several cast and wrought magnesium-based alloys. Plates with a thickness of 2.5--8 mm were butt joint welded with and without filler metal using a 2.5-kW CO{sub 2} laser. The investigations showed that magnesium alloys can be easily laser welded in similar and dissimilar joints. The beam characteristics of the laser leads to small welds and a deep penetration depth. Crackfree welds exhibiting low porosity and good surface finish can be achieved with appropriate process parameters. Generally, the laser welding leads to either no change or a small increase in hardness in the fusion zone (FZ) and in the heat-affected zone (HAZ) relative to the base metal. Less promising results were obtained for the cast alloy QE22, in which cracking in the age-hardened condition and a significant decrease in hardness occurred. Laser welded die cast alloys showed an extremely high level of porosity in the weld.

Weisheit, A.; Galun, R.; Mordike, B.L. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Werkstoffkunde und Werkstofftechnik

1998-04-01T23:59:59.000Z

Note: This page contains sample records for the topic "lasers electron beams" 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.


461

Fundamental physics at an X-ray free electron laser  

E-Print Network (OSTI)

X-ray free electron lasers (FELs) have been proposed to be constructed both at SLAC in the form of the so-called Linac Coherent Light Source as well as at DESY, where the so-called XFEL laboratory is part of the design of the electron-positron linear collider TESLA. In addition to the immediate applications in condensed matter physics, chemistry, material science, and structural biology, X-ray FELs may be employed also to study some physics issues of fundamental nature. In this context, one may mention the boiling of the vacuum (Schwinger pair creation in an external field), horizon physics (Unruh effect), and axion production. We review these X-ray FEL opportunities of fundamental physics and discuss the necessary technological improvements in order to achieve these goals.

A. Ringwald

2001-12-19T23:59:59.000Z

462

Fracture toughness of thick section dissimilar electron beam weld joints  

SciTech Connect

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

Kocak, M.; Junghans, E.

1994-12-31T23:59:59.000Z

463

Carbon ion beam focusing using laser irradiated heated diamond hemispherical shells  

SciTech Connect

Experiments preformed at the Los Alamos National Laboratory's Trident Laser Facility were conducted to observe the acceleration and focusing of carbon ions via the TNSA mechanism using hemispherical diamond targets. Trident is a 200TW class laser system with 80J of 1 {micro}m, short-pulse light delivered in 0.5ps, with a peak intensity of 5 x 10{sup 20} W/cm{sup 2}. Targets where Chemical Vapor Deposition (CVD) diamonds formed into hemispheres with a radius of curvature of 400{micro}m and a thickness of 5{micro}m. The accelerated ions from the hemisphere were diagnosed by imaging the shadow of a witness copper mesh grid located 2mm behind the target onto a film pack located 5cm behind the target. Ray tracing was used to determine the location of the ion focal spot. The TNSA mechanism favorably accelerates hydrogen found in and on the targets. To make the carbon beam detectable, targets were first heated to several hundred degrees Celsius using a CW, 532nm, 8W laser. Imaging of the carbon beam was accomplished via an auto-radiograph of a nuclear activated lithium fluoride window in the first layer of the film pack. The focus of the carbon ion beam was determined to be located 630 {+-} 110 {micro}m from the vertex of the hemisphere.

Offermann, Dustin T [Los Alamos National Laboratory; Flippo, Kirk A [Los Alamos National Laboratory; Gaillard, Sandrine A [Los Alamos National Laboratory

2009-01-01T23:59:59.000Z

464

Adapting High Brightness Relativistic Electron Beams for Ultrafast Science  

E-Print Network (OSTI)

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

Scoby, Cheyne Matthew

2012-01-01T23:59:59.000Z