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Note: This page contains sample records for the topic "lasers electron beams" from the National Library of EnergyBeta (NLEBeta).
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1

Electron and laser beam welding  

SciTech Connect

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

1986-01-01T23:59:59.000Z

2

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

3

Rippled beam free electron Laser Amplifier  

DOE Patents (OSTI)

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

Carlsten, Bruce E.

1998-04-21T23:59:59.000Z

4

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

5

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.

6

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.

7

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.

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

10

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

11

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

12

Beam conditioner for free electron lasers and synchrotrons  

DOE Patents (OSTI)

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

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

1998-01-01T23:59:59.000Z

13

Electron beam switched discharge for rapidly pulsed lasers  

DOE Patents (OSTI)

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

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

1981-01-01T23:59:59.000Z

14

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.

15

Electron beam-switched discharge for rapidly pulsed lasers  

DOE Patents (OSTI)

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

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

1979-12-11T23:59:59.000Z

16

Energy Spread Reduction of Electron Beams Produced via Laser Wake  

Science Conference Proceedings (OSTI)

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

Pollock, B

2012-03-19T23:59:59.000Z

17

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

DOE Patents (OSTI)

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

Schlitt, L.G.

1982-01-26T23:59:59.000Z

18

Electron beam magnetic switch for a plurality of free electron lasers  

DOE Patents (OSTI)

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

Schlitt, Leland G. (Livermore, CA)

1984-01-01T23:59:59.000Z

19

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

SciTech Connect

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

Nunes, A.C. Jr.

1985-08-01T23:59:59.000Z

20

Laser-driven relativistic electron beam interaction with solid dielectric  

SciTech Connect

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

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

2012-07-30T23:59:59.000Z

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

Beam Conditioning for Free Electron Lasers:Consequences and Methods  

Science Conference Proceedings (OSTI)

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

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

2010-12-14T23:59:59.000Z

22

Electron Beam Charge Diagnostics for Laser Plasma Accelerators  

SciTech Connect

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

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

2011-06-27T23:59:59.000Z

23

Characterisation of electron beams from laser-driven particle accelerators  

Science Conference Proceedings (OSTI)

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

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

2012-12-21T23:59:59.000Z

24

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

SciTech Connect

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

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

2012-05-30T23:59:59.000Z

25

Relativistic electron beam generator  

DOE Patents (OSTI)

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

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

1975-11-11T23:59:59.000Z

26

Free Electron Laser  

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

Free Electron Laser Building Exterior Top Floor Control Room RF Gallery User Lab Beam Enclosure Injector Linear Accelerator Wiggler Magnet Return Line Free Electron Laser Most...

27

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

Science Conference Proceedings (OSTI)

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

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

2011-04-15T23:59:59.000Z

28

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

Science Conference Proceedings (OSTI)

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

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

2010-06-01T23:59:59.000Z

29

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

30

The Nike electron-beam-pumped KrF laser amplifiers  

SciTech Connect

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

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

1997-04-01T23:59:59.000Z

31

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

SciTech Connect

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

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

2012-06-15T23:59:59.000Z

32

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

SciTech Connect

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

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

2010-10-01T23:59:59.000Z

33

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

E-Print Network (OSTI)

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

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

2002-09-18T23:59:59.000Z

34

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

Science Conference Proceedings (OSTI)

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

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

2012-06-15T23:59:59.000Z

35

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

Science Conference Proceedings (OSTI)

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

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

2009-03-15T23:59:59.000Z

36

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

SciTech Connect

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

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

1991-01-01T23:59:59.000Z

37

Catalac free electron laser  

DOE Patents (OSTI)

A catalac free electron laser using a rf linac (catalac) which acts as a catalyst to accelerate an electron beam in an initial pass through the catalac and decelerate the electron beam during a second pass through the catalac is described. During the second pass through the catalac, energy is extracted from the electron beam and transformed to energy of the accelerating fields of the catalac to increase efficiency of the device. Various embodiments disclose the use of post linacs to add electron beam energy extracted by the wiggler and the use of supplementary catalacs to extract energy at various energy peaks produced by the free electron laser wiggler to further enhance efficiency of the catalac free electron laser. The catalac free electron laser can be used in conjunction with a simple resonator, a ring resonator, or as an amplifier in conjunction with a master oscillator laser.

Brau, C.A.; Swenson, D.A.; Boyd, T.J. Jr.

1979-12-12T23:59:59.000Z

38

Catalac free electron laser  

DOE Patents (OSTI)

A catalac free electron laser using a rf linac (catalac) which acts as a catalyst to accelerate an electron beam in an initial pass through the catalac and decelerate the electron beam during a second pass through the catalac. During the second pass through the catalac, energy is extracted from the electron beam and transformed to energy of the accelerating fields of the catalac to increase efficiency of the device. Various embodiments disclose the use of post linacs to add electron beam energy extracted by the wiggler and the use of supplementary catalacs to extract energy at various energy peaks produced by the free electron laser wiggler to further enhance efficiency of the catalac free electron laser. The catalac free electron laser can be used in conjunction with a simple resonator, a ring resonator or as an amplifier in conjunction with a master oscillator laser.

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

1982-01-01T23:59:59.000Z

39

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

SciTech Connect

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

Dunning, Michael

2012-07-19T23:59:59.000Z

40

Circular free-electron laser  

DOE Patents (OSTI)

A high efficiency, free electron laser is described 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, C.A.; Kurnit, N.A.; Cooper, R.K.

1982-01-26T23:59:59.000Z

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

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

42

Laser Beams  

E-Print Network (OSTI)

Community needs to work together to provide the technical case for funding an IFE program. IFE program should nurture competition, with judgments made on the basis of technical progress and the potential of the various approaches to IFE. Direct-drive with lasers looks very attractive for IFE, the physics and needed technologies are mature and advancing. KrF provides physics advantages for direct drive. KrFs demonstrated performance is competitive with solid state lasers as a high-rep-rate durable, efficient IFE driver. (on several important parameters KrF technology leads) Direct Laser Drive is a better choice for Energy

Steve Obenschain

2010-01-01T23:59:59.000Z

43

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

E-Print Network (OSTI)

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

Fu, Yongqi

44

Creating intense polarized electron beam via laser stripping and spin-orbit interaction  

DOE Green Energy (OSTI)

The recent advance in laser field make it possible to excite and strip electrons with definite spin from hydrogen atoms. The sources of hydrogen atoms with orders of magnitude higher currents (than that of the conventional polarized electron cathods) can be obtained from H{sup -} sources with good monochromatization. With one electron of H{sup -} stripped by a laser, the remained electron is excited to upper state (2P{sup 3/2} and 2P{sup 1/2}) by a circular polarization laser light from FEL. Then, it is excited to a high quantum number (n=7) with mostly one spin direction due to energy level split of the states with a definite direction of spin and angular momentum in an applied magnetic field and then it is stripped by a strong electric field of an RF cavity. This paper presents combination of lasers and fields to get high polarization and high current electron source.

Danilov, V.; Ptitsyn, V.; Gorlov, T.

2010-12-01T23:59:59.000Z

45

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

Science Conference Proceedings (OSTI)

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

Ramirez, J. J.

1980-01-01T23:59:59.000Z

46

Laser beam generating apparatus  

DOE Patents (OSTI)

Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect). 11 figures.

Warner, B.E.; Duncan, D.B.

1993-12-28T23:59:59.000Z

47

Laser beam generating apparatus  

DOE Patents (OSTI)

Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect).

Warner, Bruce E. (Livermore, CA); Duncan, David B. (Auburn, CA)

1994-01-01T23:59:59.000Z

48

Laser beam generating apparatus  

DOE Patents (OSTI)

Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus is described. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect). 7 figures.

Warner, B.E.; Duncan, D.B.

1994-02-15T23:59:59.000Z

49

Laser beam generating apparatus  

DOE Patents (OSTI)

Laser beam generating apparatus including a septum segment disposed longitudinally within the tubular structure of the apparatus. The septum provides for radiatively dissipating heat buildup within the tubular structure and for generating relatively uniform laser beam pulses so as to minimize or eliminate radial pulse delays (the chevron effect).

Warner, Bruce E. (Livermore, CA); Duncan, David B. (Auburn, CA)

1993-01-01T23:59:59.000Z

50

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

E-Print Network (OSTI)

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

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

2013-10-29T23:59:59.000Z

51

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

E-Print Network (OSTI)

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

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

2013-01-01T23:59:59.000Z

52

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

53

Rf feedback free electron laser  

DOE Patents (OSTI)

A free electron laser system and electron beam system for a free electron laser are provided 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, C.A.; Swenson, D.A.; Boyd, T.J. Jr.

1979-11-02T23:59:59.000Z

54

Generation of tunable, 100-800 MeV quasi-monoenergetic electron beams from a laser-wakefield accelerator in the blowout regime  

Science Conference Proceedings (OSTI)

In this paper, we present results on a scalable high-energy electron source based on laser wakefield acceleration. The electron accelerator using 30-80 TW, 30 fs laser pulses, operates in the blowout regime, and produces high-quality, quasi-monoenergetic electron beams in the range 100-800 MeV. These beams have angular divergence of 1-4 mrad, and 5%-25% energy spread, with a resulting brightness 10{sup 11} electrons mm{sup -2} MeV{sup -1} mrad{sup -2}. The beam parameters can be tuned by varying the laser and plasma conditions. The use of a high-quality laser pulse and appropriate target conditions enables optimization of beam quality, concentrating a significant fraction of the accelerated charge into the quasi-monoenergetic component.

Banerjee, S.; Powers, N. D.; Ramanathan, V.; Ghebregziabher, I.; Brown, K. J.; Maharjan, C. M.; Chen, S.; Umstadter, D. P. [Department of Physics and Astronomy, University of Nebraska, Lincoln, Nebraska 68588-0299 (United States); Beck, A.; Lefebvre, E.; Kalmykov, S. Y.; Shadwick, B. A. [CEA, DAM, DIF, 91297 Arpajon Cedex (France)

2012-05-15T23:59:59.000Z

55

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

56

Laser beam alignment system  

DOE Patents (OSTI)

A plurality of pivotal reflectors direct a high-power laser beam onto a workpiece, and a rotatable reflector is movable to a position wherein it intercepts the beam and deflects a major portion thereof away from its normal path, the remainder of the beam passing to the pivotal reflectors through an aperture in the rotating reflector. A plurality of targets are movable to positions intercepting the path of light traveling to the pivotal reflectors, and a preliminary adjustment of the latter is made by use of a low-power laser beam reflected from the rotating reflector, after which the same targets are used to make a final adjustment of the pivotal reflectors with the portion of the high-power laser beam passed through the rotating reflector.

Kasner, William H. (11686 Althea Dr., Pittsburgh, PA 15235); Racki, Daniel J. (712 Union Cemetery Rd., Greensburg, PA 15601); Swenson, Clark E. (228 Scott Dr., Monroeville, PA 15146)

1984-01-01T23:59:59.000Z

57

Electron beam device  

DOE Patents (OSTI)

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

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

1975-08-12T23:59:59.000Z

58

Excitation density distribution in electron-beam-pumped ZnSe semiconductor lasers  

Science Conference Proceedings (OSTI)

The spatial density distribution of the absorbed energy in ZnSe semiconductor lasers excited by electrons with energies from 2 keV to 1 MeV is calculated by the Monte-Carlo method. Approximate analytic expressions determining the absorbed energy of electrons in ZnSe are presented. The pump power threshold in a semiconductor quantum-well ZnSe structure is experimentally determined. The lasing threshold in such structures is estimated as a function of the electron energy. (active media)

Donskoi, E N; Zalyalov, A N; Petrushin, O N; Savel'ev, Yu A; Tarasov, M D; Shigaev, Yu S [Russian Federal Nuclear Center 'All-Russian Scientific Research Institute of Experimental Physics', Sarov, Nizhnii Novgorod Region (Russian Federation); Zhdanova, E V; Zverev, M M; Peregudov, D V [Moscow State Institute of Radio-Engineering, Electronics and Automation (Technical University), Moscow (Russian Federation); Ivanov, S V; Sedova, I V; Sorokin, S V [A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation)

2008-12-31T23:59:59.000Z

59

Short pulse free electron laser amplifier  

DOE Patents (OSTI)

Method and apparatus for amplification of a laser pulse in a free electron laser amplifier where the laser pulse duration may be a small fraction of the electron beam pulse duration used for amplification. An electron beam pulse is passed through a first wiggler magnet and a short laser pulse to be amplified is passed through the same wiggler so that only the energy of the last fraction, f, (f<1) of the electron beam pulse is consumed in amplifying the laser pulse. After suitable delay of the electron beam, the process is repeated in a second wiggler magnet, a third, . . . , where substantially the same fraction f of the remainder of the electron beam pulse is consumed in amplification of the given short laser pulse in each wiggler magnet region until the useful electron beam energy is substantially completely consumed by amplification of the laser pulse.

Schlitt, Leland G. (Livermore, CA); Szoke, Abraham (Fremont, CA)

1985-01-01T23:59:59.000Z

60

Laser Beam Delivery [Laser Applications Laboratory] - Nuclear...  

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

Laser Glazing of Railroad Rails High Power Laser Beam Delivery Decontamination and Decommissioning Refractory Alloy Welding Robots Applications Other Facilities Other Capabilities...

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

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

62

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

63

Multifrequency, single pass free electron laser  

DOE Patents (OSTI)

A method for simultaneous amplification of laser beams with a sequence of frequencies in a single pass, using a relativistic beam of electrons grouped in a sequence of energies corresponding to the sequence of laser beam frequencies. The method allows electrons to pass from one potential well or "bucket" to another adjacent bucket, thus increasing efficiency of trapping and energy conversion.

Szoke, Abraham (Fremont, CA); Prosnitz, Donald (Walnut Creek, CA)

1985-01-01T23:59:59.000Z

64

Free electron laser with masked chicane  

DOE Patents (OSTI)

A free electron laser (FEL) is provided with an accelerator for outputting electron beam pulses; a buncher for modulating each one of the electron beam pulses to form each pulse into longitudinally dispersed bunches of electrons; and a wiggler for generating coherent light from the longitudinally dispersed bunches of electrons. The electron beam buncher is a chicane having a mask for physically modulating the electron beam pulses to form a series of electron beam bunches for input to the wiggler. In a preferred embodiment, the mask is located in the chicane at a position where each electron beam pulse has a maximum dispersion.

Nguyen, Dinh C. (Los Alamos, NM); Carlsten, Bruce E. (Los Alamos, NM)

1999-01-01T23:59:59.000Z

65

Electron Beam Melting (EBM)  

Science Conference Proceedings (OSTI)

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

66

Electron Beam Melting  

Science Conference Proceedings (OSTI)

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

67

Low Emittance Electron Beam Studies  

Science Conference Proceedings (OSTI)

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

Tikhoplav, Rodion; /Rochester U.

2006-04-01T23:59:59.000Z

68

Free electron lasers  

SciTech Connect

A review of experimental and theoretical concepts of a free electron laser is given. The possibilities of scaling these lasers to high powers are discussed. (MOW)

Brau, C.A.

1980-01-01T23:59:59.000Z

69

Laser beam guard clamps  

DOE Patents (OSTI)

A quick insert and release laser beam guard panel clamping apparatus having a base plate mountable on an optical table, a first jaw affixed to the base plate, and a spring-loaded second jaw slidably carried by the base plate to exert a clamping force. The first and second jaws each having a face acutely angled relative to the other face to form a V-shaped, open channel mouth, which enables wedge-action jaw separation by and subsequent clamping of a laser beam guard panel inserted through the open channel mouth. Preferably, the clamping apparatus also includes a support structure having an open slot aperture which is positioned over and parallel with the open channel mouth.

Dickson, Richard K. (Stockton, CA)

2010-09-07T23:59:59.000Z

70

FREE-ELECTRON LASERS  

E-Print Network (OSTI)

1977. First Operation of a Free-Electron Laser. Phys . __Radiation from a High-Gain Free-Electeon Lasee Amplifier. ~1984. Variable-Wiggler Free-Electron-Laser Oscillat.ion.

Sessler, A.M.

2008-01-01T23:59:59.000Z

71

FREE-ELECTRON LASERS  

SciTech Connect

We can now produce intense, coherent light at wavelengths where no conventional lasers exist. The recent successes of devices known as free-electron lasers mark a striking confluence of two conceptual developments that themselves are only a few decades old. The first of these, the laser, is a product of the fifties and sixties whose essential characteristics have made it a staple resource in almost every field of science and technology. In a practical sense, what defines a laser is its emission of monochromatic, coherent light (that is, light of a single wavelength, with its waves locked in step) at a wavelength in the infrared, visible, or ultraviolet region of the electromagnetic spectrum. A second kind of light, called synchrotron radiation, is a by-product of the age of particle accelerators and was first observed in the laboratory in 1947. As the energies of accelerators grew in the 1960s and 70s, intense, incoherent beams of ultraviolet radiation and x--rays became available at machines built for high-energy physics research. Today, several facilities operate solely as sources of synchrotron light. Unlike the well-collimated monochromatic light emitted by lasers, however, this incoherent radiation is like a sweeping searchlight--more accurately, like the headlight of a train on a circular track--whose wavelengths encompass a wide spectral band. Now, in several laboratories around the world, researchers have exploited the physics of these two light sources and have combined the virtues of both in a single contrivance, the free-electron laser, or FEL (1). The emitted light is laserlike in its narrow, sharply peaked spectral distribution and in its phase coherence, yet it can be of a wavelength unavailable with ordinary lasers. Furthermore, like synchrotron radiation, but unlike the output of most conventional lasers, the radiation emitted by free-electron lasers can be tuned, that is, its wavelength can be easily varied across a wide range. The promise of this new technology extends from the fields of solid-state physics, gas- and liquid-phase photochemistry, and surface catalysis to futuristic schemes for ultrahigh-energy linear accelerators.

Sessler, A.M.; Vaughan, D.

1986-04-01T23:59:59.000Z

72

Synchronization and Characterization of an Ultra-Short Laser for Photoemission and Electron-Beam Diagnostics Studies at a Radio Frequency Photoinjector  

SciTech Connect

A commercially-available titanium-sapphire laser system has recently been installed at the Fermilab A0 photoinjector laboratory in support of photoemission and electron beam diagnostics studies. The laser system is synchronized to both the 1.3-GHz master oscillator and a 1-Hz signal use to trigger the radiofrequency system and instrumentation acquisition. The synchronization scheme and performance are detailed. Long-term temporal and intensity drifts are identified and actively suppressed to within 1 ps and 1.5%, respectively. Measurement and optimization of the laser's temporal profile are accomplished using frequency-resolved optical gating.

Maxwell, Timothy; Ruan, Jinhao; Piot, Philippe; Lumpkin, Alex

2012-03-01T23:59:59.000Z

73

Electron Beam Powder Bed Processes  

Science Conference Proceedings (OSTI)

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

74

Electron-beam-controlled gas lasers: discussion from the engineering viewpoint. Part II. Problems in the electrical design of very high energy systems  

SciTech Connect

Some problem areas in the design of very-high-energy electronbeam- controlled short-pulse gas lasers are discussed. One of the prime areas of interest is the high-voltage pulse generators for driving the electron gun and gas pumping. The use of pulse-forming networks for improving energy-transfer efficiency is discussed. The use of thermionic cathode devices will require a large ac power installation. The properties of alternate electron sources (cold cathode and plasma cathode devices) are reviewed. The impact of laser beam energy density limitations on system geometry and electrical design are discussed last. (auth)

Riepe, K.B.; Stapleton, R.E.

1973-01-01T23:59:59.000Z

75

Laser beam alignment apparatus and method  

DOE Patents (OSTI)

The disclosure relates to an apparatus and method for laser beam alignment. Thermoelectric properties of a disc in a laser beam path are used to provide an indication of beam alignment and/or automatic laser alignment.

Gruhn, Charles R. (Martinez, CA); Hammond, Robert B. (Los Alamos, NM)

1981-01-01T23:59:59.000Z

76

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

77

Novel method for characterizing relativistic electron beams in a harsh laser-plasma environment  

E-Print Network (OSTI)

repetition rates and which, at the same time, allow for usage in very space-limited environments. Various ultrashort la- ser pulses that yield electric fields of the order of TV/m when focused to spots of a few almost 30 years ago1 to use the ultrahigh electric fields in laser-produced plasmas to ac- celerate

Kroupp, Eyal

78

FREE ELECTRON LASERS  

E-Print Network (OSTI)

1984). Colson, W. B. , "Free electron laser theory," Ph.D.M. 0. , Spitzer, R. , editors, Free Electron Generators ofM.D. , Spitzer, R. , editors, Free Electron Generators of

Colson, W.B.

2008-01-01T23:59:59.000Z

79

Compact Alignment for Diagnostic Laser Beams  

Physicist and optical engineer Mike Rushford developed the laser beam . centering and pointing system. The laser beam . centering and pointing system

80

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

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

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

82

Free electron laser designs for laser amplification  

DOE Patents (OSTI)

Method for laser beam amplification by means of free electron laser techniques. With wiggler magnetic field strength B.sub.w and wavelength .lambda..sub.w =2.pi./k.sub.w regarded as variable parameters, the method(s) impose conditions such as substantial constancy of B.sub.w /k.sub.w or k.sub.w or B.sub.w and k.sub.w (alternating), coupled with a choice of either constant resonant phase angle or programmed phase space "bucket" area.

Prosnitz, Donald (Walnut Creek, CA); Szoke, Abraham (Fremont, CA)

1985-01-01T23:59:59.000Z

83

All-optical Time-resolved Measurement of Laser Energy Modulation in a Relativistic Electron Beam  

Science Conference Proceedings (OSTI)

Hamiltonian light-front theory has been proposed as a promising method for solving bound states problems in quantum field theory a long time ago, see, e.g., the review article[1] for its various advantages compared to the traditional instant-form theories. Recently the Basis Light-Front Quantization (BLFQ) approach [2, 3] has been developed as a nonperturbative approach to solve Hamiltonian light-front quantum field theory. Numerical efficiency is a key advantage of this approach. The basic idea of BLFQ is to represent the theory in an optimal basis which respects many symmetries of the theory and thus minimizes the dimensionality of the Hamiltonian for a fixed precision. Specifically, the BLFQ approach employs a plane wave basis in the light-front longitudinal direction and a 2D harmonic oscillator basis in the transverse directions. In previous work [3] this approach has been applied to evaluate the anomalous magnetic moment of electrons which are confined in an external trap with an extrapolation to the zero trap limit. In this work we extend and improve this approach in several aspects including the direct evaluation of a free electron system. This article is organized as follows: In Sec. 2 we discuss the key extensions and improvements made in this work over Ref [3]; in Sec. 3 we present the numerical results for the electron anomalous magnetic moment evaluated in different harmonic oscillator bases and compare to the perturbation theory result. Finally we conclude and give an outline for future works in Sec. 4.

Xiang, D.; Colby, E.; Dunning, M.; Gilevich, S.; Hast, C.; Jobe, K.; McCormick, D.; Nelson, J.; Raubenheimer, T.O.; Soong, K.; Stupakov, G.; Szalata, Z.; Walz, D.; Weathersby, S.; Woodley, M.; /SLAC

2012-02-15T23:59:59.000Z

84

Relativistic electron beam device  

DOE Patents (OSTI)

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

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

1975-07-01T23:59:59.000Z

85

Laser-beam-alignment system  

DOE Patents (OSTI)

A plurality of pivotal reflectors direct a high-power laser beam onto a workpiece, and a rotatable reflector is movable to a position wherein it intercepts the beam and deflects a major portion thereof away from its normal path, the remainder of the beam passing to the pivotal reflectors through an aperture in the rotating reflector. A plurality of targets are movable to positions intercepting the path of light traveling to the pivotal reflectors, and a preliminary adjustment of the latter is made by use of a low-power laser beam reflected from the rotating reflector, after which the same targets are used to make a final adjustment of the pivotal reflectors with the portion of the high-power laser beam passed through the rotating reflector. The system was developed to cut the casings of spent nuclear fuel elements into segments as the initial step in recovering usable fuel. (WHK)

Kasner, W.H.; Racki, D.J.; Swenson, C.E.

1982-02-26T23:59:59.000Z

86

Short rise time intense electron beam generator  

DOE Patents (OSTI)

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

Olson, Craig L. (Albuquerque, NM)

1987-01-01T23:59:59.000Z

87

Pulsed electron beam precharger  

Science Conference Proceedings (OSTI)

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

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

1990-01-01T23:59:59.000Z

88

Electron Beam Melting (EBM) II  

Science Conference Proceedings (OSTI)

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

89

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

90

Protective laser beam viewing device  

SciTech Connect

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

91

PLASMA WAKE EXCITATION BY LASERS OR PARTICLE BEAMS  

SciTech Connect

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

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

2011-04-01T23:59:59.000Z

92

Beam transport and monitoring for laser plasma accelerators  

SciTech Connect

The controlled transport and imaging of relativistic electron beams from laser plasma accelerators (LPAs) are critical for their diagnostics and applications. Here we present the design and progress in the implementation of the transport and monitoring system for an undulator based electron beam diagnostic. Miniature permanent-magnet quadrupoles (PMQs) are employed to realize controlled transport of the LPA electron beams, and cavity based electron beam position monitors for non-invasive beam position detection. Also presented is PMQ calibration by using LPA electron beams with broadband energy spectrum. The results show promising performance for both transporting and monitoring. With the proper transport system, XUV-photon spectra from THUNDER will provide the momentum distribution of the electron beam with the resolution above what can be achieved by the magnetic spectrometer currently used in the LOASIS facility.

Nakamura, K.; Sokollik, T.; Tilborg, J. van; Gonsalves, A. J.; Shaw, B.; Shiraishi, S.; Mittal, R.; De Santis, S.; Byrd, J. M.; Leemans, W. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States) and University of California, Berkeley, CA 94720 (United States)

2012-12-21T23:59:59.000Z

93

Free electron laser using Rf coupled accelerating and decelerating structures  

DOE Patents (OSTI)

A free electron laser and free electron laser amplifier using beam transport devices for guiding an electron beam to a wiggler of a free electron laser and returning the electron beam to decelerating cavities disposed adjacent to the accelerating cavities of the free electron laser. Rf energy is generated from the energy depleted electron beam after it emerges from the wiggler by means of the decelerating cavities which are closely coupled to the accelerating cavities, or by means of a second bore within a single set of cavities. Rf energy generated from the decelerated electron beam is used to supplement energy provided by an external source, such as a klystron, to thereby enhance overall efficiency of the system.

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

1984-01-01T23:59:59.000Z

94

Interaction of relativistic electron beams with high Z plasmas  

SciTech Connect

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

Kershaw, D.S.

1975-10-27T23:59:59.000Z

95

Scattering apodizer for laser beams  

SciTech Connect

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

96

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

97

Repetitively pumped electron beam device  

DOE Patents (OSTI)

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

Schlitt, L.G.

1979-07-24T23:59:59.000Z

98

Repetitively pumped electron beam device  

DOE Patents (OSTI)

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

Schlitt, Leland G. (Livermore, CA)

1979-01-01T23:59:59.000Z

99

NIST SURF: Beamline 10: Electron beam imaging  

Science Conference Proceedings (OSTI)

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

2012-11-19T23:59:59.000Z

100

Effects of finite beam and plasma temperature on the growth rate of a two-stream free electron laser with background plasma  

SciTech Connect

A fluid theory is used to derive the dispersion relation of two-stream free electron laser (TSFEL) with a magnetic planar wiggler pump in the presence of background plasma (BP). The effect of finite beams and plasma temperature on the growth rate of a TSFEL has been verified. The twelve order dispersion equation has been solved numerically. Three instabilities, FEL along with the TS and TS-FEL instabilities occur simultaneously. The analysis in the case of cold BP shows that when the effect of the beam temperature is taken into account, both instable bands of wave-number and peak growth rate in the TS instability increase, but peak growth of the FEL and TS-FEL instabilities decreases. Thermal motion of the BP causes to diminish the TS instability and it causes to decrease the FEL and TS-FEL instabilities. By increasing the beam densities and lowering initial velocities (in the collective Raman regime), growth rate of instabilities increases; however, it has opposite behavior in the Campton regime.

Mahdizadeh, N. [Department of Physics, Sabzevar Branch, Islamic Azad University, Sabzevar (Iran, Islamic Republic of); Aghamir, F. M. [Department of Physics, University of Tehran, Tehran (Iran, Islamic Republic of)

2013-02-28T23:59:59.000Z

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

High-efficiency free-electron laser results  

Science Conference Proceedings (OSTI)

Results obtained with a tapered-wiggler free-electron laser demonstrate the concepts proposed by Morton for enhanced efficiency and show deceleration of electrons by as much as 7%, and extraction of more than 3% of the total electron-beam energy as laser energy when the laser is operated as an amplifier. The experiment is presently being reconfigured to examine its performance as a laser oscillator.

Boyer, K.; Baru, C.A.; Newnam, B.E.; Stein, W.E.; Warren, R.W.; Winston, J.G.; Young, L.M.

1983-01-01T23:59:59.000Z

102

Electron-Beam Irradiation of Solar Cells  

Science Conference Proceedings (OSTI)

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

2013-02-27T23:59:59.000Z

103

Staging laser plasma accelerators for increased beam energy  

E-Print Network (OSTI)

Staging Laser Plasma Accelerators for Increased Beam Energy94720, USA Abstract. Staging laser plasma accelerators is anefficient way of mitigating laser pump depletion in laser

Panasenko, Dmitriy

2010-01-01T23:59:59.000Z

104

Density effect on relativistic electron beams in a plasma fiber  

Science Conference Proceedings (OSTI)

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

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

2010-11-15T23:59:59.000Z

105

Electra: An Electron Beam Pumped KrF Rep-Rate Laser System for Inertial Fusion Energy  

Science Conference Proceedings (OSTI)

High Average Power Laser and Other IFE R&D / Eighteenth Topical Meeting on the Technology of Fusion Energy (Part 1)

P. M. Burns et al.

106

Beam Characterizations at Femtosecond Electron Beam Facility  

SciTech Connect

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

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

2006-03-17T23:59:59.000Z

107

Electron beam cutting  

DOE Patents (OSTI)

A method for the cutting of holes 20 Angstroms in diameter, or lines 20 Angstroms wide in a material having positive ionic conduction by the use of a focused electron probe is described. The holes and lines are stable under ambient conditions. 2 figs.

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

1985-04-02T23:59:59.000Z

108

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

109

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

Science Conference Proceedings (OSTI)

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

Elmer, J W

2009-01-23T23:59:59.000Z

110

Shimmed electron beam welding process  

DOE Patents (OSTI)

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

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

2002-01-01T23:59:59.000Z

111

Enhanced laser beam coupling to a plasma  

DOE Patents (OSTI)

Density perturbations are induced in a heated plasma by means of a pair of oppositely directed, polarized laser beams of the same frequency. The wavelength of the density perturbations is equal to one half the wavelength of the laser beams. A third laser beam is linearly polarized and directed at the perturbed plasma along a line that is perpendicular to the direction of the two opposed beams. The electric field of the third beam is oriented to lie in the plane containing the three beams. The frequency of the third beam is chosen to cause it to interact resonantly with the plasma density perturbations, thereby efficiently coupling the energy of the third beam to the plasma.

Steiger, Arno D. (Pleasanton, CA); Woods, Cornelius H. (Livermore, CA)

1976-01-01T23:59:59.000Z

112

Electron beam dynamics for the ISIS bremsstrahlung beam generation system  

E-Print Network (OSTI)

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

Block, Robert E. (Robert Edward)

2011-01-01T23:59:59.000Z

113

A laser-wire beam-energy and beam-profile monitor at the BNL linac  

SciTech Connect

In 2009 a beam-energy monitor was installed in the high energy beam transport (HEBT) line at the Brookhaven National Lab linac. This device measures the energies of electrons stripped from the 40mA H{sup -} beam by background gas. Electrons are stripped by the 2.0x10{sup -7}torr residual gas at a rate of {approx}1.5x10{sup -8}/cm. Since beam electrons have the same velocities as beam protons, the beam proton energy is deduced by multiplying the electron energy by m{sub p}/m{sub e}=1836. A 183.6MeV H{sup -} beam produces 100keV electrons. In 2010 we installed an optics plates containing a laser and scanning optics to add beam-profile measurement capability via photodetachment. Our 100mJ/pulse, Q-switched laser neutralizes 70% of the beam during its 10ns pulse. This paper describes the upgrades to the detector and gives profile and energy measurements.

Connolly, R.; Degen, C.; DeSanto, L.; Meng, W.; Michnoff, R.; Minty, M.; Nayak, S.

2011-03-28T23:59:59.000Z

114

Coherence delay augmented laser beam homogenizer  

SciTech Connect

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

115

Light modulated electron beam driven radiofrequency emitter  

DOE Patents (OSTI)

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

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

1979-10-10T23:59:59.000Z

116

Momentum spread in a relativistic electron beam in an undulator  

Science Conference Proceedings (OSTI)

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

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

2012-11-15T23:59:59.000Z

117

APPARATUS FOR ELECTRON BEAM HEATING CONTROL  

DOE Patents (OSTI)

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

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

1962-09-18T23:59:59.000Z

118

Chirping the LCLS Electron Beam  

E-Print Network (OSTI)

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

P. Emma

2000-01-01T23:59:59.000Z

119

LOW ENERGY BEAM PROCESSES IN ELECTRONIC MATERIALS ...  

Science Conference Proceedings (OSTI)

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

120

Electron Beam Melting: The New Directional Solidification  

Science Conference Proceedings (OSTI)

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

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

Electron Beam Ion Trap (EBIT) Facility  

Science Conference Proceedings (OSTI)

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

2013-06-06T23:59:59.000Z

122

Synchronization of Sub-Picosecond Electron and Laser Pulses  

SciTech Connect

Sub-picosecond laser-electron synchronization is required to take full advantage of the experimental possibilities arising from the marriage of modern high intensity lasers and high brightness electron beams in the same laboratory. Two particular scenarios stand out in this regard, injection of ultra-short electron pulses in short wavelength laser-driven plasma accelerators, and Compton scattering of laser photons from short electron pulses. Both of these applications demand synchronization, which is subpicosecond, with tens of femtosecond synchronization implied for next-generation experiments. Typically, an RF electron accelerator is synchronized to a short pulse laser system by detecting the repetition signal of a laser oscillator, adjusted to an exact subharmonic of the linac RF frequency, and multiplying or phase locking this signal to produce the master RF clock. Pulse-to-pulse jitter characteristic of self-mode-locked laser oscillators represents a direct contribution to the ultimate timing jitter between a high intensity laser focus and electron beam at the interaction point, or a photocathode drive laser in an RF photoinjector. This timing jitter problem has been addressed most seriously in the context of the RF photoinjector, where the electron beam properties are sensitive functions of relative timing jitter. The timing jitter achieved in synchronized photocathode drive laser systems is near, or slightly below one picosecond. The ultimate time of arrival jitter of the beam at the photoinjector exit is typically a bit smaller than the photocathode drive-laser jitter due to velocity compression effects in the first RF cell of the gun. This tendency of the timing of the electron beam arrival at a given spatial point to lock to the RF lock is strongly reinforced by use of magnetic compression.

Rosenzweig, J.B.; Le Sage G.P.

2000-08-15T23:59:59.000Z

123

Free-electron-laser design for laser amplification  

DOE Patents (OSTI)

A method for laser beam amplification by means of free electron laser techniques is described. With wiggler magnetic field strength B/sub w/ and wavelength lambda/sub w/ = 2..pi../k/sub w/ regarded as variable parameters, the method(s) impose conditions such as substantial constancy of B/sub w//k/sub w/ or k/sub w/ or B/sub w/ and k/sub w/ (alternating), coupled with a choice of either constant resonant phase angle or programmed phase space bucket area.

Prosnitz, D.; Szoke, A.

1982-01-26T23:59:59.000Z

124

Synchronization of sub-picosecond electron and laser pulses  

SciTech Connect

Sub-picosecond laser-electron synchronization is required to take full advantage of the experimental possibilities arising from the marriage of modern high intensity lasers and high brightness electron beams in the same laboratory. Two particular scenarios stand out in this regard, injection of ultra-short electron pulses in short wavelength laser-driven plasma accelerators, and Compton scattering of laser photons from short electron pulses. Both of these applications demand synchronization, which is sub-picosecond, with tens of femtosecond synchronization implied for next generation experiments. The design of a microwave timing modulator system is now being investigated in more detail. (AIP) {copyright} {ital 1999 American Institute of Physics.}

Rosenzweig, J.B. [UCLA Department of Physics and Astronomy, 405 Hilgard Ave., Los Angeles, California 90095 (United States); Le Sage, G.P. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

1999-07-01T23:59:59.000Z

125

Synchronization of sub-picosecond electron and laser pulses  

SciTech Connect

Sub-picosecond laser-electron synchronization is required to take full advantage of the experimental possibilities arising from the marriage of modern high intensity lasers and high brightness electron beams in the same laboratory. Two particular scenarios stand out in this regard, injection of ultra-short electron pulses in short wavelength laser-driven plasma accelerators, and Compton scattering of laser photons from short electron pulses. Both of these applications demand synchronization, which is sub-picosecond, with tens of femtosecond synchronization implied for next generation experiments. The design of a microwave timing modulator system is now being investigated in more detail.

Rosenzweig, J. B.; Le Sage, G. P. [UCLA Department of Physics and Astronomy, 405 Hilgard Ave., Los Angeles, California 90095 (United States); Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

1999-07-12T23:59:59.000Z

126

LS-303 Generation of Bright, Tunable, Polarized ?-Ray Sources by Scattering Laser Pulses from APS Electron Beams  

E-Print Network (OSTI)

We calculate the performance of possible Advanced Photon Source (APS) ?-ray sources for applications in nuclear physics research. For the APS storage ring, it is possible to generate tagged ?-ray photon fluxes of 10 8, 0.710 8, and 0.310 8 photons/s at photon energies of 1, 1.7, and 2.8 GeV, respectively. For untagged photons, fluxes higher than 10 8 photons/s are possible for those energies. For the injection booster, an untagged ?-ray photon flux up to 10 8 photons/s at energy ranging from 5 MeV to 1 GeV is possible. This can be achieved using off-the-shelf commercial Ti:Sa laser systems. The photon fluxes predicted here are in general one to two orders of magnitude higher than facilities with similar photon energies. 1.

Y. Li; Y. Chae; L. Emery; Z. Huang; K. Harkay; J. Lewellen; S. V. Milton; V. Sajaev

2003-01-01T23:59:59.000Z

127

Inverse Free Electron Laser Heater for the LCLS  

Science Conference Proceedings (OSTI)

The Linac Coherent Light Source (LCLS) free electron laser employs an RF photocathode gun that yields a 1nC bunch a few picoseconds long, which must be further compressed to yield the high current required for Self Amplified Spontaneous Emission (SASE) gain. The electron beam from the RF photocathode gun is quite sensitive to microbunching instabilities such as coherent synchrotron radiation (CSR) in the compressor chicanes and longitudinal space charge (LSC) in the linac. These effects can be Landau damped by adding energy spread to the electron bunch prior to compression. They propose to do this by co-propagating an infrared laser beam with the electron bunch in an undulator in the LCLS injector beamline. The undulator is placed in a four bend magnet chicane to allow the Ir laser beam to propagate colinearly with the e-beam while it oscillates in the undulator. The IR laser beam is derived from the photocathode gun drive laser, so the two beams are synchronized. Simulations presented elsewhere in these proceedings show that the laser interaction damps the microbunching instabilities to a very great extent. This paper is a description of the design of the laser heater.

Bentson, L.D.; Bolton, P.; Carr, R.; Dowell, D.; Emma, P.; Gilevich, S.; Huang, Z.; Welch, J.J.; Wu, J.; /SLAC

2005-05-11T23:59:59.000Z

128

Apparatus for laser beam profile measurements  

DOE Patents (OSTI)

Apparatus for measuring the spatial intensity profile of the output beam from a continuous-wave laser oscillator. The rapid and repetitive passing of a small aperture through the otherwise totally blocked output beam of the laser under investigation provides an easily interpretable, real-time measure of the intensity characteristics thereof when detected by a single detector and the signal generated thereby displayed on an oscilloscope synthronized to the motion of the aperture.

Barnes, N.P.; Gettemy, D.J.

1985-01-30T23:59:59.000Z

129

Electron number density measurement by ruby laser interferometry  

DOE Green Energy (OSTI)

A pulsed ruby laser beam with 3 nsec full width at half magnitude is used to obtain space- and time-resolved, two-dimensional interferometric measurements of electron number density in CO/sub 2/-laser produced plasma in hydrogen near the focal spot. The focal plane of the CO/sub 2/ laser is arranged to be at the exit of a free-expansion jet, with the beam incident from the vacuum side. Several nanoseconds after breakdown, a shock wave is formed, propagating transverse to the incident laser beam direction. Behind the transverse propagating shock is an on axis density minimum, which results in laser-beam self trapping. During the initial pulse duration of the CO/sub 2/ laser, the radial boundary of the plasma column increases linearly in time.

Chu, T.K.; Johnson, L.C.; Schuss, J.J.

1977-01-01T23:59:59.000Z

130

Propagation characteristics of a Gaussian laser beam in plasma with modulated collision frequency  

SciTech Connect

The propagation characteristics of a Gaussian laser beam in cold plasma with the electron collision frequency modulated by laser intensity are presented. The nonlinear dynamics of the ponderomotive force, which induce nonlinear self-focusing as opposed to spatial diffraction, are considered. The effective dielectric function of the Drude model and complex eikonal function are adopted in deriving coupled differential equations of the varying laser beam parameters. In the framework of ponderomotive nonlinearity, the frequency of electron collision in plasmas, which is proportional to the spatial electron density, is strongly interrelated with the laser beam propagation characteristics. Hence, the propagation properties of the laser beam and the modulated electron collision frequency distribution in plasma were studied and explained in depth. Employing this self-consistent method, the obtained simulation results approach practical conditions, which is of significance to the study of laser-plasma interactions.

Wang Ying; Yuan Chengxun; Zhou Zhongxiang; Gao Ruilin [Department of Physics, Harbin Institute of Technology, Harbin 150001 (China); Li Lei; Du Yanwei [Shanghai Key Laboratory of Space Intelligent Control Technology, Shanghai 201108 (China)

2012-08-15T23:59:59.000Z

131

Laser rock Drilling Using a Superpulse CO2 Laser Beam  

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

by A Super-Pulsed CO 2 Laser Beam Z. Xu and C. B. Reed Technology Development Division, Argonne National Laboratory Argonne, Illinois 60540 R.A. Parker Packer Geoscience...

132

Beam/seam alignment control for electron beam welding  

DOE Patents (OSTI)

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

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

1980-01-01T23:59:59.000Z

133

In situ laser processing in a scanning electron microscope  

Science Conference Proceedings (OSTI)

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

134

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

135

Transmission of Megawatt Relativistic Electron Beams Through Millimeter Apertures  

E-Print Network (OSTI)

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

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

2013-05-01T23:59:59.000Z

136

Physics of relativistic electron beams in rectangular and cylindrical geometries  

SciTech Connect

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

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

1975-11-01T23:59:59.000Z

137

An Alternative Form of Laser Beam Characterization  

SciTech Connect

Careful characterization of laser beams used in materials processing such as welding and drilling is necessary to obtain robust, reproducible processes and products. Recently, equipment and techniques have become available which make it possible to rapidly and conveniently characterize the size, shape, mode structure, beam quality (Mz), and intensity of a laser beam (incident power/unit area) as a function of distance along the beam path. This facilitates obtaining a desired focused spot size and also locating its position. However, for a given position along the beam axis, these devices typically measure where the beam intensity level has been reduced to I/ez of maximum intensity at that position to determine the beam size. While giving an intuitive indication of the beam shape since the maximum intensity of the beam varies greatly, the contour so determined is not an iso-contour of any parameter related to the beam intensity or power. In this work we shall discuss an alternative beam shape formulation where the same measured information is plotted as contour intervals of intensity.

KNOROVSKY,GERALD A.; MACCALLUM,DANNY O.

2000-06-30T23:59:59.000Z

138

Generation of low-divergence laser beams  

DOE Patents (OSTI)

Apparatus for transforming a conventional beam of coherent light, having a Gaussian energy distribution and relatively high divergence, into a beam in which the energy distribution approximates a single, non-zero-order Bessel function and which therefore has much lower divergence. The apparatus comprises a zone plate having transmitting and reflecting zones defined by the pattern of light interference produced by the combination of a beam of coherent light with a Gaussian energy distribution and one having such a Bessel distribution. The interference pattern between the two beams is a concentric array of multiple annuli, and is preferably recorded as a hologram. The hologram is then used to form the transmitting and reflecting zones by photo-etching portions of a reflecting layer deposited on a plate made of a transmitting material. A Bessel beam, containing approximately 50% of the energy of the incident beam, is produced by passing a Gaussian beam through such a Bessel zone plate. The reflected beam, also containing approximately 50% of the incident beam energy and having a Bessel energy distribution, can be redirected in the same direction and parallel to the transmitted beam. Alternatively, a filter similar to the Bessel zone plate can be placed within the resonator cavity of a conventional laser system having a front mirror and a rear mirror, preferably axially aligned with the mirrors and just inside the front mirror to generate Bessel energy distribution light beams at the laser source. 11 figures.

Kronberg, J.W.

1993-09-14T23:59:59.000Z

139

Generation of low-divergence laser beams  

DOE Patents (OSTI)

This invention is comprised of an apparatus for transforming a conventional beam of coherent light, having a Gaussian energy distribution and relatively high divergence, into a beam in which the energy distribution approximates a single, non-zero-order Bessel function and which therefore has much lower divergence. The apparatus comprises a zone plate having transmitting and reflecting zones defined by the pattern of light interference produced by the combination of a beam of coherent light with a Gaussian energy distribution and one having such a Bessel distribution. The interference pattern between the two beams is a concentric array of multiple annuli, and is preferably recorded as a hologram. The hologram is then used to form the transmitting, and reflecting zones by photo-etching portions of a reflecting layer deposited on a plate made of a transmitting material. A Bessel beam, containing approximately 50% of the energy of the incident beam, is produced by passing a Gaussian beam through such a Bessel zone plate. The reflected beam, also containing approximately 50% of the incident beam energy and having a Bessel energy distribution, can be redirected in the same direction and parallel to the transmitted beam. Alternatively, a filter similar to the Bessel zone plate can be placed within the resonator cavity of a conventional laser system having a front mirror and a rear mirror, preferably axially aligned with the mirrors and just inside the front mirror to generate Bessel energy distribution light beams at the laser source.

Kronberg, J.W.

1992-12-31T23:59:59.000Z

140

Generation of low-divergence laser beams  

DOE Patents (OSTI)

Apparatus for transforming a conventional beam of coherent light, having a Gaussian energy distribution and relatively high divergence, into a beam in which the energy distribution approximates a single, non-zero-order Bessel function and which therefore has much lower divergence. The apparatus comprises a zone plate having transmitting and reflecting zones defined by the pattern of light interference produced by the combination of a beam of coherent light with a Gaussian energy distribution and one having such a Bessel distribution. The interference pattern between the two beams is a concentric array of multiple annuli, and is preferably recorded as a hologram. The hologram is then used to form the transmitting and reflecting zones by photo-etching portions of a reflecting layer deposited on a plate made of a transmitting material. A Bessel beam, containing approximately 50% of the energy of the incident beam, is produced by passing a Gaussian beam through such a Bessel zone plate. The reflected beam, also containing approximately 50% of the incident beam energy and having a Bessel energy distribution, can be redirected in the same direction and parallel to the transmitted beam. Alternatively, a filter similar to the Bessel zone plate can be placed within the resonator cavity of a conventional laser system having a front mirror and a rear mirror, preferably axially aligned with the mirrors and just inside the front mirror to generate Bessel energy distribution light beams at the laser source.

Kronberg, James W. (108 Independent Blvd., Aiken, SC 29801)

1993-01-01T23:59:59.000Z

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.


141

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

142

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

143

Radiation from laser accelerated electron bunches: Coherent terahertz and femtosecond X-rays  

E-Print Network (OSTI)

of coherent transition radiation generated at a plasma-and G. Fubiani, Terahertz radiation from laser acceleratedW. P. Leemans, Synchrotron radiation from electron beams in

2004-01-01T23:59:59.000Z

144

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

145

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

E-Print Network (OSTI)

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

Ivanyan, M I; Tsakanov, V M

2002-01-01T23:59:59.000Z

146

Multi-GeV Electron Generation Using Texas Petawatt Laser  

Science Conference Proceedings (OSTI)

We present simulation results and experimental setup for multi-GeV electron generation by a laser plasma wake field accelerator (LWFA) driven by the Texas Petawatt (TPW) laser. Simulations show that, in plasma of density n{sub e} = 2-4x10{sup 17} cm{sup -3}, the TPW laser pulse (1.1 PW, 170 fs) can self-guide over 5 Rayleigh ranges, while electrons self-injected into the LWFA can accelerate up to 7 GeV. Optical diagnostic methods employed to observe the laser beam self-guiding, electron trapping and plasma bubble formation and evolution are discussed. Electron beam diagnostics, including optical transition radiation (OTR) and electron gamma ray shower (EGS) generation, are discussed as well.

Wang, X.; Du, D.; Yi, S. A.; Kalmykov, S.; D'avignon, E.; Fazel, N.; Zagdzaj, R.; Reed, S.; Dong, P.; Henderson, W.; Dyer, G.; Bernstein, A.; Gaul, E.; Martinez, M.; Shvets, G.; Ditmire, T.; Downer, M. [Department of Physics, University of Texas at Austin, Austin, TX 78712 (United States)

2010-11-04T23:59:59.000Z

147

Towards demonstration of electron cooling with bunched electron beam  

SciTech Connect

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

Fedotov, A.

2012-01-11T23:59:59.000Z

148

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

149

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

150

Electron Beam Imaging - Programmaster.org  

Science Conference Proceedings (OSTI)

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

151

Produced by Selective Electron Beam Melting  

Science Conference Proceedings (OSTI)

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

152

LASER BEAM PROFILE MONITOR DEVELOPMENT AT BNL FOR SNS.  

SciTech Connect

A beam profile monitor for H-beams based on laser photoneutralization is being developed at Brookhaven National Laboratory (BNL) for use on the Spallation Neutron Source (SNS) [l]. An H ion has a first ionization potential of 0.75eV and can be neutralized by light from a Nd:YAG laser (h=1064nm). To measure beam profiles, a narrow laser beam is passed through the ion beam neutralizing a portion of the H-beam struck by the laser. The laser trajectory is stepped across the ion beam. At each laser position, the reduction of the beam current caused by the laser is measured. A proof-of-principle experiment was done earlier at 750keV. This paper reports on measurements made on 200MeV beam at BNL and with a compact scanner prototype at Lawrence Berkeley National Lab on beam from the SNS RFQ.

CONNOLLY,R.; CAMERON,P.; CUPOLO,J.; GASSNER,D.; GRAU,M.; KESSELMAN,M.; PENG,S.; SIKORA,R.

2002-05-06T23:59:59.000Z

153

Precision Absolute Beam Current Measurement of Low Power Electron Beam  

SciTech Connect

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

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

2012-11-01T23:59:59.000Z

154

Feasibility study for mega-electron-volt electron beam tomography  

SciTech Connect

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

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

2012-09-15T23:59:59.000Z

155

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

2013-03-28T23:59:59.000Z

156

Electron Beam Transport in Advanced Plasma Wave Accelerators  

SciTech Connect

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

Williams, Ronald L

2013-01-31T23:59:59.000Z

157

Puffin: A three dimensional, unaveraged free electron laser simulation code  

SciTech Connect

An unaveraged 3D model of the free electron laser (FEL) is presented which is capable of modelling electron interactions with broad bandwidth radiation that includes electron beam shot-noise and coherent spontaneous emission effects. Non-localised electron transport throughout the beam is modelled self-consistently allowing better modelling of systems where a larger electron energy range is required. The FEL interaction can be modelled with undulator fields of variable polarisation. A modular undulator system allows insertion of other magnetic structures, such as chicanes. A set of working equations that describe the model are derived, the parallel numerical method that solves them described, and some example FEL interactions presented.

Campbell, L. T. [University of Strathclyde (SUPA), Glasgow G4 0NG (United Kingdom); ASTeC, STFC Daresbury Laboratory and Cockcroft Institute, Warrington WA4 4AD (United Kingdom); McNeil, B. W. J. [University of Strathclyde (SUPA), Glasgow G4 0NG (United Kingdom)

2012-09-15T23:59:59.000Z

158

Influence of electron beam parameters on coherent electron cooling  

Science Conference Proceedings (OSTI)

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

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

2012-05-20T23:59:59.000Z

159

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

DOE Patents (OSTI)

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

Neil, George R. (Williamsburg, VA)

1996-01-01T23:59:59.000Z

160

Intense steady state electron beam generator  

DOE Patents (OSTI)

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

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

1990-07-17T23:59:59.000Z

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

Hybrid free electron laser devices  

Science Conference Proceedings (OSTI)

We consider hybrid free electron laser devices consisting of Cerenkov and undulator sections. We will show that they can in principle be used as segmented devices and also show the possibility of exploiting Cerenkov devices for the generation of nonlinear harmonic coherent power. We discuss both oscillator and amplifier schemes.

Asgekar, Vivek; Dattoli, G. [Department of Physics, University of Pune, Pune 411007 (India); ENEA, Unita Tecnico Scientifica Technologie Fisiche, Avanzate, Centro Ricerche Frascati, C.P. 65-00044 Frascati, Rome (Italy)

2007-03-15T23:59:59.000Z

162

Guiding of Laser Beams in Plasmas by Radiation Cascade Compression  

SciTech Connect

The near-resonant heatwave excitation of an electron plasma wave (EPW) can be employed for generating trains of few-fs electromagnetic pulses in rarefied plasmas. The EPW produces a co-moving index grating that induces a laser phase modulation at the beat frequency. Consequently, the cascade of sidebands red- and blue-shifted from the fundamental by integer multiples of the beat frequency is generated in the laser spectrum. When the beat frequency is lower than the electron plasma frequency, the phase chirp enables laser beatnote compression by the group velocity dispersion [S. Kalmykov and G. Shvets, Phys. Rev. E 73, 046403 (2006)]. In the 3D cylindrical geometry, the frequency-downshifted EPW not only modulates the laser frequency, but also causes the pulse to self-focus [P. Gibbon, Phys. Fluids B 2, 2196 (1990)]. After self-focusing, the multi-frequency laser beam inevitably diverges. Remarkably, the longitudinal beatnote compression can compensate the intensity drop due to diffraction. A train of high-intensity radiation spikes with continually evolving longitudinal profile can be self-guided over several Rayleigh lengths in homogeneous plasmas. High amplitude of the EPW is maintained over the entire propagation length. Numerical experiments on the electron acceleration in the cascade-driven (cascade-guided) EPW [using the code WAKE by P. Mora and T. M. Antonsen Jr., Phys. Plasmas 4, 217 (1997)] show that achieving GeV electron energy is possible under realistic experimental parameters.

Kalmykov, Serguei; Shvets, Gennady [Department of Physics, University of Texas at Austin, Austin, Texas 78712 (United States); Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)

2006-11-27T23:59:59.000Z

163

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

164

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.

Pardy, M

2006-01-01T23:59:59.000Z

165

Coherence delay augmented laser beam homogenizer  

DOE Patents (OSTI)

It is an object of the present invention to provide an apparatus that can reduce the apparent coherence length of a laser beam so the beam can be used with an inexpensive homogenizer to produce an output beam with a uniform spatial intensity across its entire cross section. It is a further object of the invention to provide an improved homogenizer with a variable aperture size that is simple and easily made. It is still an additional object of the invention to provide an improved liquid filled homogenizer utilizing total internal reflection for improved efficiency. These, and other objects of the invention are realized by using a ``coherence delay line,`` according to the present invention, in series between a laser and a homogenizer. The coherence delay line is an optical ``line`` that comprises two mirrors, one partially reflecting, and one totally reflecting, arranged so that light incident from the laser first strikes the partially reflecting mirror. A portion of the beam passes through, and a portion is reflected back to the totally reflecting mirror.

Rasmussen, P.; Bernhardt, A.

1991-12-31T23:59:59.000Z

166

Electron beam depolarization in a damping ring  

SciTech Connect

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

Minty, M.

1993-04-01T23:59:59.000Z

167

Emittance growth from electron beam modulation  

SciTech Connect

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

Blaskiewicz, M.

2009-12-01T23:59:59.000Z

168

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

Science Conference Proceedings (OSTI)

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

169

NIST Puts a New Twist on the Electron Beam  

Science Conference Proceedings (OSTI)

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

2011-01-19T23:59:59.000Z

170

Free-electron laser driven by the LBNL laser-plasma accelerator  

E-Print Network (OSTI)

Free-electron laser driven by the LBNL laser-plasmaA design of a compact free-electron laser (FEL), generatingare considered. Keywords: Free-electron laser, laser-plasma

Schroeder, C. B.

2010-01-01T23:59:59.000Z

171

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

E-Print Network (OSTI)

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

Yang, Daegil

2009-12-01T23:59:59.000Z

172

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

173

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

174

LASER BASED DIAGNOSTICS FOR MEASURING H- BEAM PARAMETERS  

Science Conference Proceedings (OSTI)

In recent years, a number of laser based H- beam diagnostics systems have been developed in the Spallation Neutron Source (SNS). This talk reviews three types of laser-based diagnostics at SNS: the laser wire profile monitors at superconducting linac (SCL), the laser based transverse emittance measurement system at high energy beam transport (HEBT), and the laser bunch shape monitor at medium energy beam transport (MEBT). Measurement performance will be reported and major technical challenges in the design, implementation, and operation of the laser based diagnostics at accelerator facilities will be addressed.

Liu, Yun [ORNL; Aleksandrov, Alexander V [ORNL; Blokland, Willem [ORNL; Deibele, Craig Edmond [ORNL; Hardin, Robert A [ORNL; Huang, Chunning [ORNL; Long, Cary D [ORNL; Menshov, Alexander A [ORNL; Pogge, James R [ORNL; Webster, Anthony W [ORNL; Zhukov, Alexander P [ORNL

2011-01-01T23:59:59.000Z

175

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

176

Relativistic electron beam plasma heating experiment  

SciTech Connect

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

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

1980-04-01T23:59:59.000Z

177

PRIMARY TESTS OF LASER / E BEAM INTERACTION IN A PLASMA CHANNEL.  

SciTech Connect

A high-energy CO{sub 2} laser is channeled in a capillary discharge. Plasma dynamic simulations confirm occurrence of guiding conditions at the relatively low axial plasma density 1 {divided_by} 4 x 10{sup 17} cm{sup -3}. A relativistic electron beam transmitted through the capillary changes its properties depending upon the plasma density. We observe focusing, defocusing or steering of the e-beam. Counter-propagation of the electron and laser beams in the plasma channel results in generation of intense picosecond x-ray pulses.

POGORELSKY,I.V.; BEN ZVI,I.; HIROSE,T.; YAKIMENKO,V.; KUSCHE,K.; SIDDONS,P.; ET AL

2002-06-23T23:59:59.000Z

178

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

179

Application of reactor-pumped lasers to power beaming  

SciTech Connect

Power beaming is the concept of centralized power generation and distribution to remote users via energy beams such as microwaves or laser beams. The power beaming community is presently performing technical evaluations of available lasers as part of the design process for developing terrestrial and space-based power beaming systems. This report describes the suitability of employing a nuclear reactor-pumped laser in a power beaming system. Although there are several technical issues to be resolved, the power beaming community currently believes that the AlGaAs solid-state laser is the primary candidate for power beaming because that laser meets the many design criteria for such a system and integrates well with the GaAs photodiode receiver array. After reviewing the history and physics of reactor-pumped lasers, the advantages of these lasers for power beaming are discussed, along with several technical issues which are currently facing reactor-pumped laser research. The overriding conclusion is that reactor-pumped laser technology is not presently developed to the point of being technially or economically competitive with more mature solid-state technologies for application to power beaming. 58 refs.

Repetti, T.E.

1991-10-01T23:59:59.000Z

180

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

SciTech Connect

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

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

A wide bandwidth free-electron laser with mode locking using current modulation.  

SciTech Connect

A new scheme for mode locking a free-electron laser amplifier is proposed based on electron beam current modulation. It is found that certain properties of the original concept, based on the energy modulation of electrons, are improved including the spectral brightness of the source and the purity of the series of short pulses. Numerical comparisons are made between the new and old schemes and between a mode-locked free-electron laser and self-amplified spontaneous emission free-electron laser. Illustrative examples using a hypothetical mode-locked free-electron laser amplifier are provided. The ability to generate intense coherent radiation with a large bandwidth is demonstrated.

Kur, E.; Dunning, D. J.; McNeil, B. W. J.; Wurtele, J.; Zholents, A. A. (Accelerator Systems Division (APS)); (Univ. of California at Berkeley); (Univ. of Strathclyde); (STFC Daresbury Lab.); (LBNL)

2011-01-20T23:59:59.000Z

182

The TriBeam System: Femtosecond Laser Based Serial Sectioning  

Science Conference Proceedings (OSTI)

Presentation Title, The TriBeam System: Femtosecond Laser Based Serial Sectioning ... Measurement and Quantification of Grain Boundary Evolution in Three...

183

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

184

Preparations for a high gradient inverse free electron laser experiment at Brookhaven national laboratory  

SciTech Connect

Preparations for an inverse free electron laser experiment at Brookhaven National Laboratory's Accelerator Test Facilty are presented. Details of the experimental setup including beam and laser transport optics are first discussed. Next, the driving laser pulse structure is investigated and initial diagnostics are explored and compared to simulations. Finally, planned improvements to the experimental setup are discussed.

Duris, J.; Li, R. K.; Musumeci, P.; Sakai, Y.; Threlkeld, E.; Williams, O.; Fedurin, M.; Kusche, K.; Pogorelsky, I.; Polyanskiy, M.; Yakimenko, V. [UCLA Department of Physics and Astronomy, Los Angeles, CA 90095 (United States); Accelerator Test Facility, Brookhaven National Laboratory, Upton, NY, 11973 (United States)

2012-12-21T23:59:59.000Z

185

Chaos in an ion-channel free-electron laser with realistic helical wiggler  

SciTech Connect

Chaotic behavior of an electron motion in a free-electron laser with realistic helical wiggler and ion-channel guiding is studied using Poincare surface-of-section maps. The effects of a realistic electron beam density on chaotic electron dynamics are investigated by considering an electron beam with Gaussian density profile in radial distance. The effects of self-fields on chaotic electron dynamics are investigated for different Gaussian beam parameters, and the results are compared with those of uniform electron beam. It is shown that the electron chaotic behavior can be controlled by changing the Gaussian beam parameter. Also, the chaotic behavior can be controlled by increasing the ion-channel and/or the electron beam densities.

Esmaeilzadeh, Mahdi [Department of Physics, Iran University of Science and Technology, Narmak, Tehran 16844 (Iran, Islamic Republic of); Taghavi, Amin [Department of Applied Science, Qaemshahr Branch, Islamic Azad University, Qaemshahr (Iran, Islamic Republic of)

2012-11-15T23:59:59.000Z

186

Observation of Synchrotron Radiation from Electrons Accelerated in a Petawatt-Laser-Generated Plasma Cavity  

Science Conference Proceedings (OSTI)

The dynamics of plasma electrons in the focus of a petawatt laser beam are studied via measurements of their x-ray synchrotron radiation. With increasing laser intensity, a forward directed beam of x rays extending to 50 keV is observed. The measured x rays are well described in the synchrotron asymptotic limit of electrons oscillating in a plasma channel. The critical energy of the measured synchrotron spectrum is found to scale as the Maxwellian temperature of the simultaneously measured electron spectra. At low laser intensity transverse oscillations are negligible as the electrons are predominantly accelerated axially by the laser generated wakefield. At high laser intensity, electrons are directly accelerated by the laser and enter a highly radiative regime with up to 5% of their energy converted into x rays.

Kneip, S.; Nagel, S. R.; Bellei, C.; Dangor, A. E.; Mangles, S. P. D.; Nilson, P. M.; Willingale, L.; Najmudin, Z. [Blackett Laboratory, Imperial College London SW7 2AZ (United Kingdom); Bourgeois, N.; Marques, J. R. [Laboratoire pour l'Utilisation des Lasers Intenses, Ecole Polytechnique, 91128 Palaiseau (France); Gopal, A. [Department of Electronics, Technological Educational Institute of Crete, Romanou, 3-GR73133 Chania (Greece); Heathcote, R. [Central Laser Facility, Rutherford Appleton Laboratory, Oxon OX11 0QX (United Kingdom); Maksimchuk, A.; Reed, S. [Center for Ultrafast Optical Science (CUOS) University of Michigan, Ann Arbor, Michigan 48109 (United States); Phuoc, K. Ta; Rousse, A. [Laboratoire d'Optique Applique, ENSTA, Ecole Polytechnique, 91761 Palaiseau (France); Tzoufras, M.; Tsung, F. S.; Mori, W. B. [Department of Physics and Astronomy and Department of Electrical Engineering, UCLA, Los Angeles, California 90095 (United States); Krushelnick, K. [Blackett Laboratory, Imperial College London SW7 2AZ (United Kingdom); Center for Ultrafast Optical Science (CUOS) University of Michigan, Ann Arbor, Michigan 48109 (United States)

2008-03-14T23:59:59.000Z

187

SLAC's Polarized Electron Source Laser System for the E-158 Parity Violation Experiment  

DOE Green Energy (OSTI)

SLAC E158 is an experiment to make the first measurement of parity violation in Moeller scattering. The left-right cross-section asymmetry in the elastic scattering of a 45-GeV polarized electron beam off unpolarized electrons in a liquid hydrogen target will be measured to an accuracy of better than 10{sup -8}, with the expected Standard Model asymmetry being approximately 10{sup -7}. An intense circularly polarized laser beam for the polarized electron source is required with the ability to quickly switch between left and right polarization states with minimal left-right asymmetries in the parameters of the electron beam. This laser beam is produced by a unique SLAC-designed, flash-lamp pumped, Ti:Sapphire laser. We present this laser system design and initial results from recent commissioning runs.

Humensky, Thomas B

2002-05-07T23:59:59.000Z

188

Electron Beam Polarization Measurement Using Touschek Lifetime Technique  

SciTech Connect

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

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

2012-08-24T23:59:59.000Z

189

MULTIPLE ELECTRON BEAM ION PUMP AND SOURCE  

DOE Patents (OSTI)

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

Ellis, R.E.

1962-02-27T23:59:59.000Z

190

Free-Electron Lasers: Present Status and Future Prospects  

E-Print Network (OSTI)

38,892 (1977). C. Brau, "Free-Electron Lasers", Science 239,115 (1988). T. Marshall, "Free-Electron Lasers", MacMillan (1985); C Brau, "Free- Electron Lasers", Academic Press (

Kim, K.-J.

2008-01-01T23:59:59.000Z

191

Effects of e-beam parameters on coherent electron cooling  

Science Conference Proceedings (OSTI)

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

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

2011-03-28T23:59:59.000Z

192

Laser Phase Errors in Seeded Free Electron Lasers  

SciTech Connect

Harmonic seeding of free electron lasers has attracted significant attention as a method for producing transform-limited pulses in the soft x-ray region. Harmonic multiplication schemes extend seeding to shorter wavelengths, but also amplify the spectral phase errors of the initial seed laser, and may degrade the pulse quality and impede production of transform-limited pulses. In this paper we consider the effect of seed laser phase errors in high gain harmonic generation and echo-enabled harmonic generation. We use simulations to confirm analytical results for the case of linearly chirped seed lasers, and extend the results for arbitrary seed laser envelope and phase.

Ratner, D.; Fry, A.; Stupakov, G.; White, W.; /SLAC

2012-04-17T23:59:59.000Z

193

Compact X-ray Free Electron Laser from a Laser-plasma Accelerator using a Transverse Gradient Undulator  

SciTech Connect

Compact laser-plasma accelerators can produce high energy electron beams with low emittance, high peak current but a rather large energy spread. The large energy spread hinders the potential applications for coherent FEL radiation generation. In this paper, we discuss a method to compensate the effects of beam energy spread by introducing a transverse field variation into the FEL undulator. Such a transverse gradient undulator together with a properly dispersed beam can greatly reduce the effects of electron energy spread and jitter on FEL performance. We present theoretical analysis and numerical simulations for SASE and seeded extreme ultraviolet and soft x-ray FELs based on laser plasma accelerators.

Huang, Zhirong; Ding, Yuantao; /SLAC; Schroeder, Carl B.; /LBL, Berkeley

2012-09-13T23:59:59.000Z

194

Two-beam detuned-cavity electron accelerator structure  

SciTech Connect

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

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

2012-12-21T23:59:59.000Z

195

Tuning of Graphene Properties via Controlled Exposure to Electron Beams  

Science Conference Proceedings (OSTI)

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

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

2011-07-01T23:59:59.000Z

196

Modeling beam-driven and laser-driven plasma Wakefield accelerators with XOOPIC  

SciTech Connect

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

Bruhwiler, David L.; Giacone, Rodolfo; Cary, John R.; Verboncoeur, John P.; Mardahl, Peter; Esarey, Eric; Leemans, Wim

2000-06-01T23:59:59.000Z

197

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

Science Conference Proceedings (OSTI)

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

198

Ionized channel generation of an intense-relativistic electron beam  

DOE Patents (OSTI)

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

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

1988-01-01T23:59:59.000Z

199

Multiple Electron Stripping of Heavy Ion Beams  

DOE Green Energy (OSTI)

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

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

2002-06-25T23:59:59.000Z

200

Laser ion source development at Holifield Radioactive Ion Beam Facility  

Science Conference Proceedings (OSTI)

This report describes the efforts made to develop a resonant-ionization laser ion source based on tunable Ti:sapphire lasers for nuclear physics and astrophysics research at Holifield Radioactive Ion Beam Facility. Three Ti:sapphire lasers have been upgraded with individual pump lasers to eliminate laser power losses due to synchronization delays. Ionization schemes for 14 elements have been obtained. Off-line studies show that the overall efficiency of the laser ion source can be as high as 40%. TaC surface coatings have been investigated for minimizing surface and bulk trapping of the atoms of interest.

Liu, Y.; Havener, C. C.; Beene, J. R. [Physics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Gottwald, T.; Mattolat, C.; Vane, C. R.; Wendt, K. [Institute of Physics, University of Mainz, D-55099 Mainz (Germany); Howe, J. Y.; Kiggans, J. [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2012-02-15T23:59:59.000Z

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.


201

Free-electron laser driven by the LBNL laser-plasma accelerator  

E-Print Network (OSTI)

OF AN XUV FEL DRIVEN BY THE LASER-PLASMA ACCELERATOR AT THEFree-electron laser driven bythe LBNL laser-plasma accelerator C. B. Schroeder ? , W. M.

Schroeder, C. B.

2010-01-01T23:59:59.000Z

202

Laser triggered injection of electrons in a laser wakefield accelerator with the colliding pulse method  

E-Print Network (OSTI)

Laser Triggered Injection ofElectrons in a Laser Wake?eld Accelerator with the CollidingAn injection scheme for a laser wake?eld accelerator that

2004-01-01T23:59:59.000Z

203

2D Optical Streaking for Ultra-Short Electron Beam Diagnostics  

SciTech Connect

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

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

2011-12-14T23:59:59.000Z

204

Laser Ion Acceleration Toward Future Ion Beam Cancer Therapy - Numerical Simulation Sudy-  

E-Print Network (OSTI)

Ion beam has been used in cancer treatment, and has a unique preferable feature to deposit its main energy inside a human body so that cancer cell could be killed by the ion beam. However, conventional ion accelerator tends to be huge in its size and its cost. In this paper a future intense-laser ion accelerator is proposed to make the ion accelerator compact. An intense femtosecond pulsed laser was employed to accelerate ions. The issues in the laser ion accelerator include the energy efficiency from the laser to the ions, the ion beam collimation, the ion energy spectrum control, the ion beam bunching and the ion particle energy control. In the study particle computer simulations were performed to solve the issues, and each component was designed to control the ion beam quality. When an intense laser illuminates a target, electrons in the target are accelerated and leave from the target; temporarily a strong electric field is formed between the high-energy electrons and the target ions, and the target ions ...

Kawata, Shigeo; Nagashima, Toshihiro; Takano, Masahiro; Barada, Daisuke; Kong, Qing; Gu, Yan Jun; Wang, Ping Xiao; Ma, Yan Yun; Wang, Wei Ming

2013-01-01T23:59:59.000Z

205

DPSS Laser Beam Quality Optimization Through Pump Current Tuning  

SciTech Connect

The goal of this study is to demonstrate how a DPSS laser beam's quality parameters can be simultaneously optimized through pump current tuning. Two DPSS lasers of the same make and model were used where the laser diode pump current was first varied to ascertain the lowest RMS noise region. The lowest noise was found to be 0.13% in this region and the best M{sup 2} value of 1.0 and highest laser output power were simultaneously attained at the same current point. The laser manufacturer reported a M{sup 2} value of 1.3 and RMS noise value of .14% for these lasers. This study therefore demonstrates that pump current tuning a DPSS laser can simultaneously optimize RMS Noise, Power and M{sup 2} values. Future studies will strive to broaden the scope of the beam quality parameters impacted by current tuning.

Omohundro, Rob; /Newport Spectra-Physics, Santa Clara; Callen, Alice; /SLAC; Sukuta, Sydney; /San Jose City Coll.

2012-03-30T23:59:59.000Z

206

Designing a beam transport system for RHIC's electron lens  

SciTech Connect

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

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

2011-03-28T23:59:59.000Z

207

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

208

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

Science Conference Proceedings (OSTI)

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

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

1989-01-01T23:59:59.000Z

209

Investigation of efficiency optimization in free electron lasers  

SciTech Connect

The dynamics of trapped particles in the presence of the wiggler magnetic field and the electromagnetic radiation field in free electron lasers were investigated. From the results of computer simulations, it was found that, for a given set of parameters, the efficiency of energy extraction from the electron beam maximizes at a particular intensity of the electromagnetic radiation. Based on the physical argument of the dynamics of the trapped particles, a criterion which predicts accurately the optimum intensity of the electromagnetic radiation was obtained. (TFD)

Kwan, T.J.T.

1979-01-01T23:59:59.000Z

210

The LLNL/UCLA high gradient inverse free electron laser  

SciTech Connect

We describe the Inverse Free Electron Accelerator currently under construction at Lawrence Livermore National Lab. Upon completion of this accelerator, high brightness electrons generated in the photoinjector blowout regime and accelerated to 50 MeV by S-band accelerating sections will interact with > 4 TW peak power Ti:Sapphire laser in a highly tapered 50 cm undulator and experience an acceleration gradient of > 200 MeV/m. We present the final design of the accelerator as well as the results of start-to-end simulations investigating preservation of beam quality and tolerances involved with this accelerator.

Moody, J. T.; Musumeci, P.; Anderson, G.; Anderson, S.; Betts, S.; Fisher, S.; Gibson, D.; Tremaine, A.; Wu, S. [Department of Physics and Astronomy, UCLA, Los Angeles California, 90095 (United States); Lawrence Livermore National Laboratory (United States)

2012-12-21T23:59:59.000Z

211

Design Alternatives for a Free Electron Laser Facility  

Science Conference Proceedings (OSTI)

The University of Wisconsin-Madison is continuing design efforts for a vacuum ultraviolet/X-ray Free Electron Laser facility. The design incorporates seeding the FEL to provide fully coherent photon output at energies up to {approx}1 keV. The focus of the present work is to minimize the cost of the facility while preserving its performance. To achieve this we are exploring variations in the electron beam driver for the FEL, in undulator design, and in the seeding mechanism. Design optimizations and trade-offs between the various technologies and how they affect the FEL scientific program will be presented.

Jacobs, K; Bosch, R A; Eisert, D; Fisher, M V; Green, M A; Keil, R G; Kleman, K J; Kulpin, J G; Rogers, G C; Wehlitz, R; Chiang, T; Miller, T J; Lawler, J E; Yavuz, D; Legg, R A

2012-07-01T23:59:59.000Z

212

PURIFICATION OF IRIDIUM BY ELECTRON BEAM MELTING  

Science Conference Proceedings (OSTI)

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

Ohriner, Evan Keith [ORNL

2008-01-01T23:59:59.000Z

213

Microradiography of electron beam braze joins  

SciTech Connect

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

Shackelford, J.F.

1980-07-24T23:59:59.000Z

214

Nonlinear transmission line based electron beam driver  

Science Conference Proceedings (OSTI)

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

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

2012-12-15T23:59:59.000Z

215

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.

Carlsten, Bruce E. (Los Alamos, NM)

1997-01-01T23:59:59.000Z

216

Study of electron beam production by a plasma focus  

SciTech Connect

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

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

1983-01-01T23:59:59.000Z

217

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

218

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

Science Conference Proceedings (OSTI)

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

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

2012-12-21T23:59:59.000Z

219

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

220

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

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

Aerosol beam-focus laser-induced plasma spectrometer device  

SciTech Connect

An apparatus for detecting elements in an aerosol includes an aerosol beam focuser for concentrating aerosol into an aerosol beam; a laser for directing a laser beam into the aerosol beam to form a plasma; a detection device that detects a wavelength of a light emission caused by the formation of the plasma. The detection device can be a spectrometer having at least one grating and a gated intensified charge-coupled device. The apparatus may also include a processor that correlates the wavelength of the light emission caused by the formation of the plasma with an identity of an element that corresponds to the wavelength. Furthermore, the apparatus can also include an aerosol generator for forming an aerosol beam from bulk materials. A method for detecting elements in an aerosol is also disclosed.

Cheng, Meng-Dawn (Oak Ridge, TN)

2002-01-01T23:59:59.000Z

222

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

SciTech Connect

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

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

2012-09-15T23:59:59.000Z

223

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, J; 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

224

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

225

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

Science Conference Proceedings (OSTI)

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

226

Electron beam accelerator with magnetic pulse compression and accelerator switching  

DOE Patents (OSTI)

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

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

1987-01-01T23:59:59.000Z

227

Electron beam accelerator with magnetic pulse compression and accelerator switching  

DOE Patents (OSTI)

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

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

1988-01-01T23:59:59.000Z

228

Electron Beam Evaporator Systems for Thin Film Deposition  

Science Conference Proceedings (OSTI)

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

2012-10-23T23:59:59.000Z

229

Electron Beam Cold Hearth Refining of Investment Casting ...  

Science Conference Proceedings (OSTI)

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

230

Endoscopic Electron-Beam Cancer Therapy | Argonne National Laboratory  

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

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

231

Experimental Observation of Energy Modulation in Electron Beams...  

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

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

232

Process Modelling of Electron Beam Welding of Aeroengine ...  

Science Conference Proceedings (OSTI)

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

233

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

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

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

234

Electron beam accelerator with magnetic pulse compression and accelerator switching  

DOE Patents (OSTI)

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

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

1984-03-22T23:59:59.000Z

235

Temperature distributions in electron beam welding cavities  

SciTech Connect

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

Shintaku, S.M.

1976-07-15T23:59:59.000Z

236

An empirical model of collective electrostatic effects for laser-beam channeling in long-scale-length relativistic plasmas  

Science Conference Proceedings (OSTI)

This work investigates the capability of ultraintense lasers with irradiance from 10{sup 18} to 10{sup 21} W cm{sup -2} to produce highly energetic electron beams from a Gaussian focus in a low-density plasma. A simple particle simulation code including a physical model of collective electrostatic effects in relativistic plasmas has been developed. Without electrostatic fields, free electrons escape from the Gaussian focal region of a 10-ps petawatt laser pulse very quickly, well before the laser field reaches its maximum amplitude. However, it has been demonstrated that the electrostatic field generated by the electron flow is able to strongly modify the range and direction of the laser-generated MeV electrons by allowing trapped electrons to experience much higher laser-intensity peaks along their trajectories. This modeling predicts some collimation but not enough to meet the requirements of fast ignition.

Yang, Jeong-Hoon; Craxton, R. Stephen [Laboratory for Laser Energetics, 250 East River Road, Rochester, New York 14623 (United States)

2011-08-15T23:59:59.000Z

237

Brookhaven's Laser Electron Accelerator Facility  

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

system to study pulse radi- olysis in the country and one of the three fast- est in the world. LEAF is also the first such de- vice based on a new photocathode electron gun that...

238

Laser beam temporal and spatial tailoring for laser shock processing  

DOE Patents (OSTI)

Techniques are provided for formatting laser pulse spatial shape and for effectively and efficiently delivering the laser energy to a work surface in the laser shock process. An appropriately formatted pulse helps to eliminate breakdown and generate uniform shocks. The invention uses a high power laser technology capable of meeting the laser requirements for a high throughput process, that is, a laser which can treat many square centimeters of surface area per second. The shock process has a broad range of applications, especially in the aerospace industry, where treating parts to reduce or eliminate corrosion failure is very important. The invention may be used for treating metal components to improve strength and corrosion resistance. The invention has a broad range of applications for parts that are currently shot peened and/or require peening by means other than shot peening. Major applications for the invention are in the automotive and aerospace industries for components such as turbine blades, compressor components, gears, etc.

Hackel, Lloyd (Livermore, CA); Dane, C. Brent (Livermore, CA)

2001-01-01T23:59:59.000Z

239

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

Science Conference Proceedings (OSTI)

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

240

MaRIE X-Ray Free-Electron Laser Pre-Conceptual Design  

SciTech Connect

The proposed Matter-Radiation Interactions in Extremes (MaRIE) facility at the Los Alamos National Laboratory will include a 50-keV X-Ray Free-Electron Laser (XFEL), a significant extension from planned and existing XFEL facilities. To prevent an unacceptably large energy spread arsing from energy diffusion, the electron beam energy should not exceed 20 GeV, which puts a significant constraint on the beam emittance. A 100-pC baseline design is presented along with advanced technology options to increase the photon flux and to decrease the spectral bandwidth through pre-bunching the electron beam.

Carlsten, Bruce E. [Los Alamos National Laboratory; Barnes, Cris W. [Los Alamos National Laboratory; Bishofberger, Kip A. [Los Alamos National Laboratory; Duffy, Leanne D. [Los Alamos National Laboratory; Heath, Cynthia E. [Los Alamos National Laboratory; Marksteiner, Quinn R. [Los Alamos National Laboratory; Nguyen, Dinh Cong [Los Alamos National Laboratory; Russell, Steven J. [Los Alamos National Laboratory; Ryne, Robert D. [Los Alamos National Laboratory; Sheffield, Richard L. [Los Alamos National Laboratory; Simakov, Evgenya I. [Los Alamos National Laboratory; Yampolsky, Nikolai A. [Los Alamos National Laboratory

2011-01-01T23:59:59.000Z

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.


241

System for obtaining smooth laser beams where intensity variations are reduced by spectral dispersion of the laser light (SSD)  

DOE Patents (OSTI)

In an SSD (smoothing by spectral dispersion) system which reduces the time-averaged spatial variations in intensity of the laser light to provide uniform illumination of a laser fusion target, an electro-optic phase modulator through which a laser beam passes produces a broadband output beam by imposing a frequency modulated bandwidth on the laser beam. A grating provides spatial and angular spectral dispersion of the beam. Due to the phase modulation, the frequencies ("colors") cycle across the beam. The dispersed beam may be amplified and frequency converted (e.g., tripled) in a plurality of beam lines. A distributed phase plate (DPP) in each line is irradiated by the spectrally dispersed beam and the beam is focused on the target where a smooth (uniform intensity) pattern is produced. The color cycling enhances smoothing and the use of a frequency modulated laser pulse prevents the formation of high intensity spikes which could damage the laser medium in the power amplifiers.

Skupsky, Stanley (Rochester, NY); Kessler, Terrance J. (Rochester, NY); Short, Robert W. (Rochester, NY); Craxton, Stephen (Rochester, NY); Letzring, Samuel A. (Honeoye Falls, NY); Soures, John (Pittsford, NY)

1991-01-01T23:59:59.000Z

242

Ionized channel generation of an intense relativistic electron beam  

DOE Patents (OSTI)

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

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

1986-03-31T23:59:59.000Z

243

Spacecraft Power Beaming Using High-Energy Lasers, Experimental Validation  

SciTech Connect

The lifetime of many spacecrafts are often limited by degradation of their electrical power subsystem, e.g. radiation-damaged solar arrays or failed batteries. Being able to beam power from terrestrial sites using high energy lasers, could alleviate this limitation, extending the lifetime of billions of dollars of satellite assets, as well as providing additional energy for electric propulsion that can be used for stationkeeping and orbital changes. In addition, extensive research at the Naval Postgraduate School (NPS) has shown the potential for annealing damaged solar cells using lasers. This paper describes that research and a proposed experiment to demonstrate the relevant concepts of high energy laser power beaming to an NPS-built and operated satellite. Preliminary results of ground experiment of laser illuminations of some of the solar panels of one of the spacecrafts are also presented.

Michael, Sherif [Naval Postgraduate School ECE Dep./Space Systems Academic Group, Monterey, CA 93943 (United States)

2008-04-28T23:59:59.000Z

244

Comparing Electron Beam Melting and Laser Melting  

Science Conference Proceedings (OSTI)

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

245

Numerical simulation of the electron beam welding process  

Science Conference Proceedings (OSTI)

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

Piotr Lacki; Konrad Adamus

2011-06-01T23:59:59.000Z

246

Electron beam lithography using plasma polymerized hexane as resist  

Science Conference Proceedings (OSTI)

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

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

2010-05-01T23:59:59.000Z

247

NOx reduction by electron beam-produced nitrogen atom injection  

DOE Patents (OSTI)

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

Penetrante, Bernardino M. (San Ramon, CA)

2002-01-01T23:59:59.000Z

248

Study of second harmonic generation by high power laser beam in magneto plasma  

SciTech Connect

This paper examines the problem of nonlinear generation of second harmonic of a high power laser pulse propagating in magnetized plasma. The propagation of strong laser beam is proposed in the direction perpendicular to a relatively weak static magnetic field. The laser pulse is taken to be linearly polarized, with the orientation of its electric field that corresponds to an ordinary electromagnetic wave. Besides the standard ponderomotive nonlinearity, the appropriate wave equation also contains the nonlinearity that arises from the relativistic electron jitter velocities. During its propagation, the laser beam gets filamented on account of relativistic and pondermotive nonlinearities present in the plasma. The generated plasma wave gets coupled into the filamentary structures of the pump beam. Due to the expected presence of the beam filamentation, the work has been carried out by considering modified paraxial approximation (i.e., beyond the standard paraxial approximation of a very broad beam). It is found that the power of the plasma wave is significantly affected by the magnetic field strength in the presence of both relativistic and pondermotive nonlinearities. It is investigated that the second harmonic generation is also considerably modified by altering the strength of magnetic field. To see the effect of static magnetic field on the harmonic generation, a key parameter, i.e., the ratio of the cyclotron frequency {omega}{sub c}=eB{sub 0}/mc over the laser frequency {omega}{sub 0} has been used, where c is the velocity of light, m and e are the mass and charge of the electron and B{sub 0} is the externally applied magnetic field.

Sharma, Prerana [Ujjain Engineering College, Ujjain, Madhya Pradesh 465010 (India); Sharma, R. P. [Centre for Energy Studies, Indian Institute of Technology, New Delhi 110016 (India)

2012-12-15T23:59:59.000Z

249

Electron energy boosting in laser-wake-field acceleration with external magnetic field Bapprox1 T and laser prepulses  

SciTech Connect

Hundred-mega-electron-volt electron beams with quasi-monoenergetic distribution, and a transverse geometrical emittance as small as approx0.02 pi mm mrad are generated by low power (7 TW, 45 fs) laser pulses tightly focused in helium gas jets in an external static magnetic field, Bapprox1 T. Generation of monoenergetic beams strongly correlates with appearance of a straight, at least 2 mm length plasma channel in a short time before the main laser pulse and with the energy of copropagating picosecond pedestal pulses (PPP). For a moderate energy PPP, the multiple or staged electron self-injection in the channel gives several narrow peaks in the electron energy distribution.

Hosokai, Tomonao [Photon Pioneers Center, Osaka University, 2-1, Yamadaoka, Suita, Osaka 565-0871, Japan and Japan Science and Technology Agency (JST), CREST, 2-1, Yamadaoka, Suita, Osaka 565-0871 (Japan); Zhidkov, Alexei [Central Research Institute of Electric Power Industry, 2-6-1 Nagasaka, Yokosuka, Kanagawa 240-0196 (Japan); Yamazaki, Atsushi [Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603 (Japan); Mizuta, Yoshio [Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita, Osaka 565-0871 (Japan); Uesaka, Mitsuru [Graduate School of Engineering, University of Tokyo, 22-2 Shirane-shirakata, Tokai, Naka, Ibaraki 319-1188 (Japan); Kodama, Ryosuke [Photon Pioneers Center, Osaka University, 2-1, Yamadaoka, Suita, Osaka 565-0871 (Japan) and Japan Science and Technology Agency (JST), CREST, 2-1, Yamadaoka, Suita, Osaka 565-0871 (Japan); Graduate School of Engineering, Osaka University, 2-1, Yamadaoka, Suita, Osaka 565-0871 (Japan)

2010-03-22T23:59:59.000Z

250

Hole-boring through clouds for laser power beaming  

Science Conference Proceedings (OSTI)

Power beaming to satellites with a ground-based laser can be limited by clouds. Hole-boring through the clouds with a laser has been proposed as a way to overcome this obstacle. This paper reviews the past work on laser hole-boring and concludes that hole-boring for direct beaming to satellites is likely to require 10--100 MW. However, it may be possible to use an airborne relay mirror at 10--25 km altitude for some applications in order to extend the range of the laser (e.g., for beaming to satellites near the horizon). In these cases, use of the relay mirror also would allow a narrow beam between the laser and the relay, as well as the possibility of reducing the crosswind if the plane matched speed with the cloud temporarily. Under these conditions, the power requirement to bore a hole through most cirrus and cirrostratus clouds might be only 500-kW if the hole is less than 1 m in diameter and if the crosswind speed is less than 10 m/s. Overcoming cirrus and cirrostratus clouds would reduce the downtime due to weather by a factor of 2. However, 500 kW is a large laser, and it may be more effective instead to establish a second power beaming site in a separate weather zone. An assessment of optimum wavelengths for hole boring also was made, and the best options were found to be 3.0--3.4 {mu}m and above 10 {mu}m.

Lipinski, R.J. [Sandia National Labs., Albuquerque, NM (United States); Walter, R.F. [W.J. Schafer Associates, Inc., Albuquerque, NM (United States)

1994-12-31T23:59:59.000Z

251

Electro-optic harmonic conversion to switch a laser beam out of a cavity  

DOE Patents (OSTI)

The present invention relates to switching laser beams out of laser cavities, and more particularly, it relates to the use of generating harmonics of the laser beam to accomplish the switching. When laser light is generatd in a laser cavity the problem arises of how to switch the laser light out of the cavity in order to make use of the resulting laser beam in a well known multitude of ways. These uses include range finding, communication, remote sensing, medical surgery, laser fusion applications and many more. The switch-out problem becomes more difficult as the size of the laser aperture grows such as in laser fusion applications. The final amplifier stages of the Nova and Novette lasers at Lawrence Livermore National Laboratory are 46 centimeters with the laser beam expanded to 74 centimeters thereafter. Larger aperture lasers are planned.

Haas, R.A.; Henesian, M.A.

1984-10-19T23:59:59.000Z

252

Molecular-beam, laser-rf, double-resonance studies of calcium monohalide radicals  

SciTech Connect

The molecular-beam, laser-rf, double-resonance technique has been described a number of times. In essence, the occurrence of a radiofrequency (rf) transition in the electronic ground state of the molecule under study is detected by an increase in the laser-induced fluorescence of the molecular beam when the rf is on resonance. The technique makes it possible to measure small energy splittings (normally spin-rotational or hyperfine) in the electronic ground state of a molecule to an absolute precision of 1 kHz. The sensitivity of the technique is high because even a very small increase in fluorescence can be easily seen if the rf is swept repeatedly and digital data-handling techniques are used. The technique is useful for ionic as well as for neutral atoms and molecules.

Childs, W.J.; Cok, D.R.; Goodman, L.S.

1981-01-01T23:59:59.000Z

253

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

SciTech Connect

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

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

2013-11-01T23:59:59.000Z

254

Theory of microdroplet and microbubble deformation by Gaussian laser beam  

E-Print Network (OSTI)

The theory for linear deformations of fluid microparticles in a laser beam of Gaussian profile is presented, when the beam focus is at the particle center as in optical trapping. Three different fluid systems are considered: water microdroplet in air, air microbubble in water, and a special oil-emulsion in water system used in experiments with optical deformation of fluid interfaces. We compare interface deformations of the three systems when illuminated by a wide (compared to particle radius) and narrow laser beams and analyse differences. Deformations of droplets are radically different from bubbles under otherwise identical conditions, due to the opposite lensing effect (converging and diverging, respectively) of the two; a droplet is deformed far more than a bubble, cetera paribus. Optical contrast is found to be of great importance to the shape obtained when comparing the relatively low-contrast oil-emulsion system to that of water droplets. We finally analyse the dynamics of particle motion when the laser beam is turned on, and compare a static beam to the case of a short pulse. The very different surface tension coefficient implies a very different time scale for dynamics: microseconds for the water-air interface and tens of milliseconds for the oil-emulsion. Surface oscillations of a water microdroplet are found always to be underdamped, while those of the oil-emulsion are overdamped; deformations of a microbubble can be either, depending on physical parameters.

Simen Ellingsen

2012-12-12T23:59:59.000Z

255

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

Science Conference Proceedings (OSTI)

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

Ratner, Daniel; /Stanford U. /SLAC

2012-05-25T23:59:59.000Z

256

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

257

PARALLEL ION BEAM PROFILE SCAN USING LASER WIRE  

Science Conference Proceedings (OSTI)

We report on the world s first experiment of a parallel profile scan of the hydrogen ion (H-) beam using a laser wire system. The system was developed at the superconducting linac of the Spallation Neutron Source (SNS) accelerator complex. The laser wire profile scanner is based on a photo-detachment process and therefore can be conducted on an operational H- beam in a nonintrusive manner. The parallel profile scanning system makes it possible to simultaneously measure profiles of the 1-MW neutron production H- beam at 9 different locations of the linac by using a single light source. This paper describes the design, optical system and software platform development, and measurement results of the parallel profile scanning system.

Liu, Yun [ORNL; Aleksandrov, Alexander V [ORNL; Huang, Chunning [ORNL; Long, Cary D [ORNL; Dickson, Richard W [ORNL

2013-01-01T23:59:59.000Z

258

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?

259

Use of an Electron Beam for Stochastic Cooling  

Science Conference Proceedings (OSTI)

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

Yaroslave Derbenev

2007-09-10T23:59:59.000Z

260

Thermal imaging diagnostics of high-current electron beams  

SciTech Connect

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

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

2012-10-15T23:59:59.000Z

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

Wavelength beam combining of quantum cascade laser arrays for remote sensing  

E-Print Network (OSTI)

Wavelength beam combining was used to co-propagate beams from 28 elements in a linear array of distributedfeedback quantum cascade lasers (DFB-QCLs). The overlap of the beams in the far-field is improved using wavelength ...

Sanchez-Rubio, Antonio

262

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

Science Conference Proceedings (OSTI)

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

263

Proton- and x-ray beams generated by ultra-fast CO(2) lasers for medical applications  

DOE Green Energy (OSTI)

Recent progress in using picosecond CO{sub 2} lasers for Thomson scattering and ion-acceleration experiments underlines their potentials for enabling secondary radiation- and particle-sources. These experiments capitalize on certain advantages of long-wavelength CO{sub 2} lasers, such as higher number of photons per energy unit, and favorable scaling of the electrons ponderomotive energy and critical plasma density. The high-flux x-ray bursts produced by Thomson scattering of the CO{sub 2} laser off a counter-propagating electron beam enabled high-contrast, time-resolved imaging of biological objects in the picosecond time frame. In different experiments, the laser, focused on a hydrogen jet, generated monoenergetic proton beams via the radiation-pressure mechanism. The strong power-scaling of this regime promises realization of proton beams suitable for laser-driven proton cancer therapy after upgrading the CO{sub 2} laser to sub-PW peak power. This planned improvement includes optimizing the 10-{mu}m ultra-short pulse generation, assuring higher amplification in the CO{sub 2} gas under combined isotopic- and power-broadening effects, and shortening the postamplification pulse to a few laser cycles (150-200 fs) via chirping and compression. These developments will move us closer to practical applications of ultra-fast CO{sub 2} lasers in medicine and other areas.

Pogorelsky, I.; Polyanskiy, M.; Yakimenko, V.; Ben-Zvi, I.; Shkolnikov, P. Najmudin, Z.; Palmer, C.A.J.; Dover, N.P.; Oliva, P; Carpinelli, M.

2011-07-01T23:59:59.000Z

264

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

265

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

266

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

267

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

SciTech Connect

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

Wilke, M.D.

1994-12-01T23:59:59.000Z

268

Focusing of diode laser beams: a simple mathematical model  

SciTech Connect

A simplified mathematical model for the far field of a monomode diode laser is employed for easy but fairly accurate computations of the optical field in the focal region. The present treatment is concerned with laser junctions significantly narrower than the wavelength. The field distribution in the plane perpendicular to the diode junction is considered in detail. The results of computations are shown to agree well with the measurements. Hence, the computational code is valuable for the designing of optical devices, such as diode--fiber couplings and laser Doppler anemometers. The present work is not concerned with design calculations for specific applications. Instead, it is intended to illustrate the general features of the proposed mathematical model of monomode diode laser beams.

Naqwi, A.; Durst, F. (Friedrich-Alexander Universitaet, Erlangan-Nurnberg, Lehrstuhl fuer Stroemungsmechanik, D-8520 Erlangan, Federal Republic of Germany (DE))

1990-04-20T23:59:59.000Z

269

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

270

CO{sub 2} Laser Ablation Propulsion Tractor Beams  

SciTech Connect

Manipulation of objects at a distance has already been achieved with no small measure of success in the realm of microscopic objects on the scale size of nanometers to micrometers in applications including laser trapping and laser tweezers. However, there has been relatively little effort to apply such remote control to macroscopic systems. A space tractor beam could be applied to a wide range of applications, including removal of orbital debris, facilitation of spacecraft docking, adjustment of satellite attitude or orbital position, etc. In this paper, an ablative laser propulsion tractor beam is demonstrated based on radiation from a CO{sub 2} laser. Cooperative, layered polymer targets were used for remote impulse generation using a CO{sub 2} laser. The use of a structured ablatant enabling switching between thrust directional parity (i.e., forward or reverse) and imparting torque to a remote target. Fluence-dependent results are presented in the context of polymer ablation modeling work and with consideration of confined ablation effects.

Sinko, John E. [Micro-Nano Global Center of Excellence, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603 (Japan); Schlecht, Clifford A. [Institute for Materials and Complexity, Saint Louis, MO 63112 (United States)

2010-05-06T23:59:59.000Z

271

Threshold conditions for lasing of a free electron laser oscillator with longitudinal electrostatic wiggler  

Science Conference Proceedings (OSTI)

The system of the nonlinear non-stationary equations describing spatial-temporal dynamics of the amplitudes of an ondulator radiation and a space-charge wave of a relativistic electron beam in the resonator is obtained. A free electron laser resonator with longitudinal electrostatic wiggler is considered. In the linear approximation, the threshold conditions of lasing for Raman and Compton regimes under excitation of forward and backward electromagnetic wave are achieved. In the various physical situations, the variation of the minimum length of the resonator with the amplitude of wiggler, density of electron beam, and with the reflection coefficients of resonator's mirrors is investigated.

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

2012-12-15T23:59:59.000Z

272

Electro-optic harmonic conversion to switch a laser beam out of a cavity  

DOE Patents (OSTI)

The invention is a switch to permit a laser beam to escape a laser cavity through the use of an externally applied electric field across a harmonic conversion crystal. Amplification takes place in the laser cavity, and then the laser beam is switched out by the laser light being harmonically converted with dichroic or polarization sensitive elements present to alter the optical path of the harmonically converted laser light. Modulation of the laser beam can also be accomplished by varying the external electric field.

Haas, Roger A. (Pleasanton, CA); Henesian, Mark A. (Livermore, CA)

1987-01-01T23:59:59.000Z

273

A non-intrusive beam power monitor for high power pulsed or continuous wave lasers  

DOE Patents (OSTI)

A system and method for monitoring the output of a laser is provided in which the output of a photodiode disposed in the cavity of the laser is used to provide a correlated indication of the laser power. The photodiode is disposed out of the laser beam to view the extraneous light generated in the laser cavity whose intensity has been found to be a direct correlation of the laser beam output power level. Further, the system provides means for monitoring the phase of the laser output beam relative to a modulated control signal through the photodiode monitor.

Hawsey, R.A.; Scudiere, M.B.

1991-05-29T23:59:59.000Z

274

A non-intrusive beam power monitor for high power pulsed or continuous wave lasers  

DOE Patents (OSTI)

A system for monitoring the output of a laser is provided in which the output of a photodiode disposed in the cavity of the laser is used to provide a correlated indication of the laser power. The photodiode is disposed out of the laser beam to view the extraneous light generated in the laser cavity whose intensity has been found to be a direct correlation of the laser beam output power level. Further, the system provides means for monitoring the phase of the laser output beam relative to a modulated control signal through the photodiode monitor. 4 figs.

Hawsey, R.A.; Scudiere, M.B.

1989-09-26T23:59:59.000Z

275

Free-Electron Laser-Powered Electron Paramagnetic Resonance Spectroscopy  

E-Print Network (OSTI)

Electron paramagnetic resonance (EPR) spectroscopy interrogates unpaired electron spins in solids and liquids to reveal local structure and dynamics; for example, EPR has elucidated parts of the structure of protein complexes that have resisted all other techniques in structural biology. EPR can also probe the interplay of light and electricity in organic solar cells and light-emitting diodes, and the origin of decoherence in condensed matter, which is of fundamental importance to the development of quantum information processors. Like nuclear magnetic resonance (NMR), EPR spectroscopy becomes more powerful at high magnetic fields and frequencies, and with excitation by coherent pulses rather than continuous waves. However, the difficulty of generating sequences of powerful pulses at frequencies above 100 GHz has, until now, confined high-power pulsed EPR to magnetic fields of 3.5 T and below. Here we demonstrate that ~1 kW pulses from a free-electron laser (FEL) can power a pulsed EPR spectrometer at 240 GHz...

Takahashi, S; Edwards, D T; van Tol, J; Ramian, G; Han, S; Sherwin, M S

2012-01-01T23:59:59.000Z

276

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

277

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

Science Conference Proceedings (OSTI)

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

278

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

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

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

279

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

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

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

280

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

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

Investigation of the electron trajectories and gain regimes of the whistler pumped free-electron laser  

SciTech Connect

A free-electron laser (FEL) scheme, which employs the whistler wave as a slow electromagnetic wave wiggler, was studied theoretically. Subjected to the transverse fields of whistler wave wiggler, the beam electrons are the source of the energy needed to produce electromagnetic radiation. The strength and the period of the wiggler field depend on the parameters of the magnetoplasma medium. This configuration has a higher tunability by controlling the plasma density, on top of the {gamma}-tunability of the conventional FELs. The theory of linear gain and electron trajectories was presented and four groups (I, II, III, and IV) of electron orbits were found in the presence of an axial guide magnetic field. Using perturbation analysis, it is found that these groups of orbits were stable except small regions of group I and IV orbits. The function {Phi} which determines the rate of change of axial velocity with beam energy was also derived. In the case in which {Phi}<0 represents a negative-mass regime in which the axial velocity accelerates as the electrons lose energy. Numerical solutions showed that by increasing the cyclotron frequency, the gain for group I and III orbits increased, while a gain decrement was obtained for group II and IV orbits.

Jafarinia, F.; Jafari, S. [Department of Physics, University of Guilan, Rasht 41335-1914 (Iran, Islamic Republic of); Mehdian, H. [Department of Physics and Institute for Plasma Research, Tarbiat Moallem University, Tehran 15614 (Iran, Islamic Republic of)

2013-04-15T23:59:59.000Z

282

Terahertz radiation from laser accelerated electron bunches  

E-Print Network (OSTI)

NUMBER 5 MAY 2004 Terahertz radiation from laser acceleratedand millimeter wave radiation from laser acceleratedNo. 5, May 2004 Terahertz radiation from laser accelerated

2004-01-01T23:59:59.000Z

283

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

DOE Patents (OSTI)

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

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

1986-04-25T23:59:59.000Z

284

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.

285

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

286

The polarized electron beam for the SLAC Linear Collider  

E-Print Network (OSTI)

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

M. Woods

1996-11-09T23:59:59.000Z

287

Electro-optic techniques in electron beam diagnostics  

Science Conference Proceedings (OSTI)

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

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

2011-06-17T23:59:59.000Z

288

A table-top laser-based source of femtosecond, collimated, ultra-relativistic positron beams  

E-Print Network (OSTI)

The generation of ultra-relativistic positron beams with short duration ($\\tau_{e^+} \\leq 30$ fs), small divergence ($\\theta_{e^+} \\simeq 3$ mrad), and high density ($n_{e^+} \\simeq 10^{14} - 10^{15}$ cm$^{-3}$) from a fully optical setup is reported. The detected positron beam propagates with a high-density electron beam and $\\gamma$-rays of similar spectral shape and peak energy, thus closely resembling the structure of an astrophysical leptonic jet. It is envisaged that this experimental evidence, besides the intrinsic relevance to laser-driven particle acceleration, may open the pathway for the small-scale study of astrophysical leptonic jets in the laboratory.

G. Sarri; W. Schumaker; A. Di Piazza; M. Vargas; B. Dromey; M. E. Dieckmann; V. Chvykov; A. Maksimchuk; V. Yanovsky; Z. H. He; B. X. Hou; J. A. Nees; A. G. R. Thomas; C. H. Keit; M. Zepf; K. Krushelnick

2013-04-19T23:59:59.000Z

289

Lateral propagation of MeV electrons generated by femtosecond laser irradiation  

Science Conference Proceedings (OSTI)

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

290

Electron Beam Instability in Left-Handed Media  

E-Print Network (OSTI)

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

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

2008-04-08T23:59:59.000Z

291

Thermal response of ceramic components during electron beam brazing  

DOE Green Energy (OSTI)

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

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

1996-03-01T23:59:59.000Z

292

The SLAC Polarized Electron Source and Beam for E-158  

E-Print Network (OSTI)

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

T. B. Humensky

2003-01-16T23:59:59.000Z

293

Design of the AGS Booster Beam Position Monitor electronics  

SciTech Connect

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

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

1991-01-01T23:59:59.000Z

294

Design of the AGS Booster Beam Position Monitor electronics  

SciTech Connect

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

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

1991-12-31T23:59:59.000Z

295

Development of a Compact Rotating-Wave Electron Beam Accelerator  

Science Conference Proceedings (OSTI)

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

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

2003-08-26T23:59:59.000Z

296

Airborne Tactical Free-Electron Laser  

Science Conference Proceedings (OSTI)

The goal of 100 kilowatts (kW) of directed energy from an airborne tactical platform has proved challenging due to the size and weight of most of the options that have been considered. However, recent advances in Free-Electron Lasers appear to offer a solution along with significant tactical advantages: a nearly unlimited magazine, time structures for periods from milliseconds to hours, radar like functionality, and the choice of the wavelength of light that best meets mission requirements. For an Airborne Tactical Free-Electron Laser (ATFEL) on a platforms such as a Lockheed C-130J-30 and airships, the two most challenging requirements, weight and size, can be met by generating the light at a higher harmonic, aggressively managing magnet weights, managing cryogenic heat loads using recent SRF R&D results, and using FEL super compact design concepts that greatly reduce the number of components. The initial R&D roadmap for achieving an ATFEL is provided in this paper. Performing this R&D is expected to further reduce the weight, size and power requirements for the FELs the Navy is currently developing for shipboard applications, as well as providing performance enhancements for the strategic airborne MW class FELs. The 100 kW ATFEL with its tactical advantages may prove sufficiently attractive for early advancement in the queue of deployed FELs.

Roy Whitney; George Neil

2007-02-01T23:59:59.000Z

297

Excitation of Accelerating Plasma Waves by Counter-propagating Laser Beams  

SciTech Connect

Generation of accelerating plasma waves using two counter-propagating laser beams is considered. Colliding-beam accelerator requires two laser pulses: the long pump and the short timing beam. We emphasize the similarities and differences between the conventional laser wakefield accelerator and the colliding-beam accelerator (CBA). The highly nonlinear nature of the wake excitation is explained using both nonlinear optics and plasma physics concepts. Two regimes of CBA are considered: (i) the short-pulse regime, where the timing beam is shorter than the plasma period, and (ii) the parametric excitation regime, where the timing beam is longer than the plasma period. Possible future experiments are also outlined.

Gennady Shvets; Nathaniel J. Fisch; and Alexander Pukhov

2001-08-30T23:59:59.000Z

298

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-

299

Electron acceleration & laser pulse compression using a laser...  

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

acceleration & laser pulse compression using a laser-plasma accelerator Wednesday, August 14, 2013 - 3:00pm SLAC, Redtail Hawk Conference Room 108A Andreas Walker, Oxford...

300

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

Science Conference Proceedings (OSTI)

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

Zholents, A.; Accelerator Systems Division (APS)

2010-09-30T23:59:59.000Z

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301

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

302

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 beams 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 beams; however there is coupling between the two beams as a result of cross phase modulation, 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. 4 figs.

Chaffee, P.H.; Henesian, M.A.; Patterson, F.G.

1990-02-26T23:59:59.000Z

303

Advanced Free Electron Laser Facility - Los Alamos National Lab ...  

The AFEL Facility is used for applications requiring high-brightness electron beams or a tunable source of high-energy infrared light pulses in the wavelength range ...

304

Beam-Riding Analysis of a Parabolic Laser-thermal Thruster  

SciTech Connect

Flight experiments with laser-propelled vehicles (lightcrafts) are often performed by wire-guidance or with spin-stabilization. Nevertheless, the specific geometry of the lightcraft's optics and nozzle may provide for inherent beam-riding properties. These features are experimentally investigated in a hovering experiment at a small free flight test range with an electron-beam sustained pulsed CO{sub 2} high energy laser. Laser bursts are adapted with a real-time control to lightcraft mass and impulse coupling for ascent and hovering in a quasi equilibrium of forces. The flight dynamics is analyzed with respect to the impulse coupling field vs. attitude, given by the lightcraft's offset and its inclination angle against the beam propagation axis, which are derived from the 3D-reconstruction of the flight trajectory from highspeed recordings. The limitations of the experimental parameters' reproducibility and its impact on flight stability are explored in terms of Julia sets. Solution statements for dynamic stabilization loops are presented and discussed.

Scharring, Stefan; Eckel, Hans-Albert [Institute of Technical Physics, German Aerospace Center, D-70569 Stuttgart, Pfaffenwaldring 38-40 (Germany); Roeser, Hans-Peter [Institute of Space Systems, University of Stuttgart, D-70569 Stuttgart, Pfaffenwaldring 31 (Germany)

2011-11-10T23:59:59.000Z

305

Experimental Generation and Characterization of Uniformly Filled Ellipsoidal Electron Beam Distributions  

E-Print Network (OSTI)

Experimental Generation and Characterization of Uniformly Filled Ellipsoidal Electron Beam Distributions

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

2008-01-01T23:59:59.000Z

306

Investigation of stimulated raman scattering using short-pulse diffraction limited laser beam near the instability threshold  

SciTech Connect

Short pulse laser plasma interaction experiments using diffraction limited beams provide an excellent platform to investigate the fundamental physics of Stimulated Raman Scattering. Detailed understanding of these laser plasma instabilities impacts the current inertial confinement fusion ignition designs and could potentially impact fast ignition when higher energy lasers are used with longer pulse durations ( > 1 kJ and> 1 ps). Using short laser pulses, experiments can be modeled over the entire interaction time of the laser using particle-in-cell codes to validate our understanding quantitatively. Experiments have been conducted at the Trident laser facility and the LULI (Laboratoire pour l'Utilisation des Lasers Intenses) to investigate stimulated Raman scattering near the threshold of the instability using 527 nm and 1059 nm laser light respectively with 1.5-3.0 ps pulses. In both experiments, the interaction beam was focused into a pre-ionized He gas-jet plasma. Measurements of the reflectivity as a function of intensity and k{lambda}{sub D} were completed at the Trident laser facility. At LULI, a 300 fs Thomson scattering probe is used to directly measure the density fluctuations of the driven electron plasma and ion acoustic waves. Work is currently underway comparing the results of the experiments with simulations using the VPIC [K. J. Bowers, et at., Phys. Plasmas, 15 055703 (2008)] particle-in-cell code. Details of the experimental results are presented in this manuscript.

Kline, John L [Los Alamos National Laboratory; Montgomery, David S [Los Alamos National Laboratory; Flippo, Kirk A [Los Alamos National Laboratory; Rose, Harvey A [Los Alamos National Laboratory; Yin, L [Los Alamos National Laboratory; Albright, B J [Los Alamos National Laboratory; Johnson, R P [Los Alamos National Laboratory; Shimada, T [Los Alamos National Laboratory; Bowers, K [Los Alamos National Laboratory; Rousseaux, C [CEA; Tassin, V [CEA; Baton, S D [FRANCE; Amiranoff, F [FRANCE; Hardin, R A [WEST VIRGINIA UNIV

2008-01-01T23:59:59.000Z

307

ELECTRON BEAM WELDING OF NUCLEAR FUEL CLADDING COMPONENTS  

SciTech Connect

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

Klein, R.F.

1963-10-01T23:59:59.000Z

308

Wiggler plane focusing in a linear free electron laser  

DOE Patents (OSTI)

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, Ernst T. (Livermore, CA)

1988-01-01T23:59:59.000Z

309

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

310

Observations of underdense plasma lens focusing of relativistic electron beams  

Science Conference Proceedings (OSTI)

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

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

2007-06-01T23:59:59.000Z

311

An interference wiggler for precise diagnostics of electron beam energy  

SciTech Connect

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

Kim, Kwang-Je

1987-03-01T23:59:59.000Z

312

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

313

Ignition feedback regenerative free electron laser (FEL) amplifier  

Science Conference Proceedings (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

314

Analysis of laser beam weldability of Inconel 738 superalloy  

Science Conference Proceedings (OSTI)

The susceptibility of pre-weld heat treated laser beam welded IN 738 superalloy to heat affected zone (HAZ) cracking was studied. A pre-weld heat treatment that produced the minimal grain boundary liquation resulted in a higher level of cracking compared to those with more intergranular liquation. This deviation from the general expectation of influence of intergranular liquation extent on HAZ microfissuring is attributable to the reduction in the ability of the base alloy to accommodate welding tensile stress that accompanied a pre-weld heat treatment condition designed to minimize intergranular liquation. Furthermore, in contrast to what has been generally reported in other nickel-based superalloys, a decrease in laser welding speed resulted in increased HAZ cracking in the IN 738, which can be attributed to exacerbated process instability at lower welding speeds.

Egbewande, A.T. [Department of Chemical and Materials Engineering, University of Alberta, Edmonton (Canada); Buckson, R.A. [Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg (Canada); Ojo, O.A., E-mail: ojo@cc.umanitoba.ca [Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg (Canada)

2010-05-15T23:59:59.000Z

315

rf modulator design and phase amplitude control for a high-power free-electron-laser linac  

SciTech Connect

The continued interest for building tunable lasers using an electron accelerator as the source of primary energy has resulted in the design of a new accelerator. Earlier work by other members of the Los Alamos team has demonstrated that this design does work in an amplifier mode. The accelerator is to be upgraded for use in an oscillator experiment and the new rf power amplifier system must meet some of the very stringent demands for power and stability placed on the electron beam for the free-electron laser (FEL) interaction to be observed. These demands are particularly stringent because the electron beam energy ultimately will be circulated back through the accelerator so that the electron beam energy not used in the FEL interaction is not wasted. These considerations have to some measure been incorporated into the design of the second FEL system at Los Alamos and are discussed.

Hoeberling, R.F.; Tallerico, P.J.

1981-01-01T23:59:59.000Z

316

Spatial and Temporal Coexistence of Stimulated Scattering Processes under Crossed-Laser-Beam Irradiation  

SciTech Connect

Spatial and temporal coexistence of ion-acoustic waves (IAW) and electron-plasma waves (EPW), driven, respectively, by stimulated Brillouin and Raman scattering, at significant levels of amplitude, has been observed under the modified conditions of a laser-plasma interaction. The results were obtained using a secondary interaction beam to modify the growth of the instabilities and the multiplexing technique of a streak camera to simultaneously record the temporal and spatial evolution of Thomson-scattered light from both the IAW and the EPW. {copyright} {ital 1999} {ital The American Physical Society}

Labaune, C.; Bauer, B.S.; Schifano, E. [Laboratoire pour l`Utilisation des Lasers Intenses, Ecole Polytechnique, Centre National de la Recherche Scientifique, 91128 Palaiseau cedex (France); Baldis, H.A.; Cohen, B.I. [Institute for Laser Science and Applications (ILSA), Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)

1999-05-01T23:59:59.000Z

317

High-Power Microwave Switch Employing Electron Beam Triggering  

Science Conference Proceedings (OSTI)

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

Jay L. Hirshfield

2012-09-19T23:59:59.000Z

318

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

319

Electron beam collector for a microwave power tube  

DOE Patents (OSTI)

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

Dandl, Raphael A. (Oak Ridge, TN)

1980-01-01T23:59:59.000Z

320

Electron beam irradiation of gemstone for color enhancement  

Science Conference Proceedings (OSTI)

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

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

2012-09-26T23:59:59.000Z

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

Suppression of shot noise and spontaneous radiation in electron beams  

Science Conference Proceedings (OSTI)

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

Litvinenko,V.

2009-08-23T23:59:59.000Z

322

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

323

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

Science Conference Proceedings (OSTI)

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

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

1997-06-01T23:59:59.000Z

324

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

325

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

326

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

SciTech Connect

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

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

2000-08-21T23:59:59.000Z

327

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

SciTech Connect

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

Marrs, R.

1998-09-30T23:59:59.000Z

328

COMMISSIONING COSY COOLER WITH ELECTRON BEAM AT NOVOSIBIRSK  

E-Print Network (OSTI)

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

Kozak, Victor R.

329

Risk Management Plan Electron Beam Ion Source Project  

E-Print Network (OSTI)

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

Homes, Christopher C.

330

A study of fast electron energy transport in relativistically intense laser-plasma interactions with large density scalelengths  

SciTech Connect

A systematic experimental and computational investigation of the effects of three well characterized density scalelengths on fast electron energy transport in ultra-intense laser-solid interactions has been performed. Experimental evidence is presented which shows that, when the density scalelength is sufficiently large, the fast electron beam entering the solid-density plasma is best described by two distinct populations: those accelerated within the coronal plasma (the fast electron pre-beam) and those accelerated near or at the critical density surface (the fast electron main-beam). The former has considerably lower divergence and higher temperature than that of the main-beam with a half-angle of {approx}20 Degree-Sign . It contains up to 30% of the total fast electron energy absorbed into the target. The number, kinetic energy, and total energy of the fast electrons in the pre-beam are increased by an increase in density scalelength. With larger density scalelengths, the fast electrons heat a smaller cross sectional area of the target, causing the thinnest targets to reach significantly higher rear surface temperatures. Modelling indicates that the enhanced fast electron pre-beam associated with the large density scalelength interaction generates a magnetic field within the target of sufficient magnitude to partially collimate the subsequent, more divergent, fast electron main-beam.

Scott, R. H. H.; Norreys, P. A. [Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Perez, F.; Baton, S. D. [LULI, Ecole Polytechnique, UMR 7605, CNRS/CEA/UPMC, Route de Saclay, 91128 Palaiseau (France); Santos, J. J.; Nicolai, Ph.; Hulin, S. [Univ. Bordeaux/CNRS/CEA, CELIA, UMR 5107, 33405 Talence (France); Ridgers, C. P. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom); Davies, J. R. [GoLP, Instituto de Plasmas e Fusao Nuclear - Laboratorio Associado, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Lancaster, K. L.; Trines, R. M. G. M. [Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Bell, A. R.; Tzoufras, M. [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Central Laser Facility, STFC Rutherford Appleton Laboratory, Harwell Oxford, Didcot, Oxford OX11 0QX (United Kingdom); Rose, S. J. [Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London, SW7 2AZ (United Kingdom)

2012-05-15T23:59:59.000Z

331

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.

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

2013-10-08T23:59:59.000Z

332

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 E N T S Designed and constructed a laser-cooled, magneto-optical trap-based lithium ion source mounted on a commercial focused ion beam system, creating the world's first lithium ion microscope

Magee, Joseph W.

333

An alternative method for metallization by laser and ion beam irradiation  

Science Conference Proceedings (OSTI)

A scanning Ar+ laser beam and a focused 30 keV Ga+ ion beam (FIB) have been used to transform an insulating (or high-resistivity semiconducting) noble metal oxide film to a conducting layer, Resulting from these experiments we propose ... Keywords: interconnects, ion irradiation, laser application, metallization

F. Machalett; K. Edinger; M. Diegel; K. Steenbeck

2002-04-01T23:59:59.000Z

334

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

335

Efficient electron injection into plasma waves using higher-order laser modes  

E-Print Network (OSTI)

waves using higher-order laser modes P. Michel, E. Esarey, ?higher-order transverse laser modes as drivers for plasmaparticu- lar, using a ring laser beam with maximum intensity

Michel, P.; Esarey, E.; Schroeder, C.B.; Shadwick, B.A.; Leemans, W.P.

2006-01-01T23:59:59.000Z

336

The use of LEDS (light-emitting diode) to simulate weak YAG-laser beams  

SciTech Connect

The purpose of this report is to determine whether and under what conditions a light-emitting diode may be used to simulate a weak YAG-laser beam that has been scattered by a distant reflecting object. By examining the differences between laser radiation and LED radiation, the author concludes that there is no theoretical reason that a LED may not be used in place of the laser beam.

Young, M.

1981-01-01T23:59:59.000Z

337

Plasma impedance and electron density in a pulsed laser channel  

Science Conference Proceedings (OSTI)

The representation of plasma impedance of gas laserdischarge and spark gap channels by an inductancecapacitance (L p ?C p ) tank circuit has been useful in describing the frequency response of a pulsed superradiant laser charging circuit. The impedance matching of these plasma channels can lead to resonant narrowing of the laser pulsewidth in superradiant nitrogen lasers. Using fluid equations to model the electron and ion plasmas

K. H. Tsui; G. H. Cavalcanti; A. S. Farias; M. D. S. Marinha; L. M. Soares; C. A. Massone

1996-01-01T23:59:59.000Z

338

Physically transparent formulation of a free-electron laser in the linear gain regime  

SciTech Connect

The recent 2-dimensional analytic theories of a free-electron laser (FEL) in the linear regime are reformulated in terms of three dimensionless ratios that describe the degree to which the characteristics of the electron beam deviate from the cold beam limit of a beam with no emittance or energy spread. In terms of these ratios, algebraic model equations of a fit that combines features of both of the 2-dimensional analyses are given as a convenient computational tool. Graphs of the FEL gain eigenvalue computed with the combined 2-D formulation illustrate that the gain and the output power at saturation are reduced from the 1-D value, when any of the ratios is larger than unity.

Barletta, W.A. [Lawrence Livermore National Lab., CA (United States); Sessler, A.M. [Lawrence Berkeley Lab., CA (United States); Yu, L.H. [Brookhaven National Lab., Upton, NY (United States)

1992-08-01T23:59:59.000Z

339

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

E-Print Network (OSTI)

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

Karlicky, M

2012-01-01T23:59:59.000Z

340

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

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

Chirped pulse inverse free-electron laser vacuum accelerator  

SciTech Connect

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

342

Beam Size Measurement by Optical Diffraction Radiation and Laser System for Compton Polarimeter  

SciTech Connect

Beam diagnostics is an essential constituent of any accelerator, so that it is named as "organs of sense" or "eyes of the accelerator." Beam diagnostics is a rich field. A great variety of physical effects or physical principles are made use of in this field. Some devices are based on electro-magnetic influence by moving charges, such as faraday cups, beam transformers, pick-ups; Some are related to Coulomb interaction of charged particles with matter, such as scintillators, viewing screens, ionization chambers; Nuclear or elementary particle physics interactions happen in some other devices, like beam loss monitors, polarimeters, luminosity monitors; Some measure photons emitted by moving charges, such as transition radiation, synchrotron radiation monitors and diffraction radiation-which is the topic of the first part of this thesis; Also, some make use of interaction of particles with photons, such as laser wire and Compton polarimeters-which is the second part of my thesis. Diagnostics let us perceive what properties a beam has and how it behaves in a machine, give us guideline for commissioning, controlling the machine and indispensable parameters vital to physics experiments. In the next two decades, the research highlight will be colliders (TESLA, CLIC, JLC) and fourth-generation light sources (TESLA FEL, LCLS, Spring 8 FEL) based on linear accelerator. These machines require a new generation of accelerator with smaller beam, better stability and greater efficiency. Compared with those existing linear accelerators, the performance of next generation linear accelerator will be doubled in all aspects, such as 10 times smaller horizontal beam size, more than 10 times smaller vertical beam size and a few or more times higher peak power. Furthermore, some special positions in the accelerator have even more stringent requirements, such as the interaction point of colliders and wigglor of free electron lasers. Higher performance of these accelerators increases the difficulty of diagnostics. For most cases, intercepting measurements are no longer acceptable, and nonintercepting method like synchrotron radiation monitor can not be applied to linear accelerators. The development of accelerator technology asks for simutanous diagnostics innovations, to expand the performance of diagnostic tools to meet the requirements of the next generation accelerators. Diffraction radiation and inverse Compton scattering are two of the most promising techniques, their nonintercepting nature avoids perturbance to the beam and damage to the instrumentation. This thesis is divided into two parts, beam size measurement by optical diffraction radiation and Laser system for Compton polarimeter. Diffraction radiation, produced by the interaction between the electric field of charged particles and the target, is related to transition radiation. Even though the theory of diffraction radiation has been discussed since 1960s, there are only a few experimental studies in recent years. The successful beam size measurement by optical diffraction radiation at CEBAF machine is a milestone: First of all, we have successfully demonstrated diffraction radiation as an effective nonintercepting diagnostics; Secondly, the simple linear relationship between the diffraction radiation image size and the actual beam size improves the reliability of ODR measurements; And, we measured the polarized components of diffraction radiation for the first time and I analyzed the contribution from edge radiation to diffraction radiation.

Chuyu Liu

2012-12-31T23:59:59.000Z

343

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

Science Conference Proceedings (OSTI)

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

344

Stroboscopic Laser Diagnostics for Detection of Ordering in One-Dimensional Ion beam.  

E-Print Network (OSTI)

A novel diagnostic method for detecting ordering in one-dimensional ion beams is presented. The ions are excited by a pulsed laser at two different positions along the beam and fluorescence is observed by a group of four photomultipliers. Correlation in fluorescence signals is firm indication that the ion beam has an ordered structure.

unknown authors

2008-01-01T23:59:59.000Z

345

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

DOE Patents (OSTI)

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

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

1996-01-01T23:59:59.000Z

346

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

347

Apparatus and method for increasing the bandwidth of a laser beam  

SciTech Connect

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

348

JLAB Electron Driver Capabilities  

Science Conference Proceedings (OSTI)

Several schemes have been proposed for adding a positron beam option at the Continuous Electron Beam Facility (CEBAF) at Jefferson Laboratory (JLAB). They involve using a primary beam of electrons or gamma rays striking a target to produce a positron beam. At JLAB electron beams are produced and used in two different accelerators, CEBAF and the JLAB FEL (Free Electron Laser). Both have low emittance and energy spread. The CEBAF beam is polarized. The FEL beam is unpolarized but the injector can produce a higher current electron beam. In this paper we describe the characteristics of these beams and the parameters relevant for positron production.

Kazimi, Reza [Jefferson Lab, 12000 Jefferson Avenue, Newport News, VA 23606 (United States)

2009-09-02T23:59:59.000Z

349

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

350

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

SciTech Connect

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

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

2005-02-28T23:59:59.000Z

351

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

Science Conference Proceedings (OSTI)

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

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

2012-06-22T23:59:59.000Z

352

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

SciTech Connect

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

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

2010-12-23T23:59:59.000Z

353

Construction of Industrial Electron Beam Plant for Wastewater Treatment  

Science Conference Proceedings (OSTI)

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

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

2004-10-06T23:59:59.000Z

354

Hot-electron production and suprathermal heat flux scaling with laser intensity from the two-plasmon-decay instability  

SciTech Connect

The fully kinetic reduced-description particle-in-cell (RPIC) method has been applied to simulations of two-plasmon-decay (TPD) instability, driven by crossed laser beams, in an inhomogeneous plasma for parameters consistent with recent direct-drive experiments related to laser-driven inertial fusion. The nonlinear saturated state is characterized by very spiky electric fields, with Langmuir cavitation occurring preferentially inside density channels produced by the ponderomotive beating of the crossed laser beams and the primary TPD Langmuir waves (LWs). The heated electron distribution function is, in all cases, bi-Maxwellian, with instantaneous hot-electron temperatures in the range 60-100 keV. The net hot-electron energy flux out of the system is a small fraction ({approx}1% to 2%) of the input laser intensity in these simulations. Scalings of the hot-electron temperature and suprathermal heat flux as functions of the laser intensity are obtained numerically from RPIC simulations. These simulations lead to the preliminary conclusion that Langmuir cavitation and collapse provide dissipation by producing suprathermal electrons, which stabilize the system in saturation and drive the LW spectrum to the small dissipation scales at the Landau cutoff. The Langmuir turbulence originates at an electron density 0.241 Multiplication-Sign the laser's critical density, where the crossed laser beams excite a 'triad' mode-a common forward LW plus a pair of backward LWs. Remnants of this 'triad' evolve in k-space and dominate the time-averaged energy spectrum. At times exceeding 10 ps, the excited Langmuir turbulence spreads toward lower densities. Comparisons of RPIC simulations with the extended Zakharov model are presented in appropriate regimes, and the necessary requirements for the validity of a quasi-linear Zakharov model (where the spatially averaged electron-velocity distribution is evolved) are verified by RPIC simulation results.

Vu, H. X. [University of California, San Diego, La Jolla, California 92093 (United States); DuBois, D. F. [Lodestar Research Corporation, Boulder, Colorado 80301 (United States); Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Myatt, J. F. [Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623 (United States); Russell, D. A. [Lodestar Research Corporation, Boulder, Colorado 80301 (United States)

2012-10-15T23:59:59.000Z

355

3D Elemental Mapping of Cells using Electron and Ion Beams  

Science Conference Proceedings (OSTI)

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

2012-10-02T23:59:59.000Z

356

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

Science Conference Proceedings (OSTI)

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

357

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

Science Conference Proceedings (OSTI)

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

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

2012-07-02T23:59:59.000Z

358

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

359

The electron beam cure of epoxy paste adhesives  

Science Conference Proceedings (OSTI)

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

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

1998-07-01T23:59:59.000Z

360

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

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

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. 3 figs.

Wilcox, R.B.

1990-01-01T23:59:59.000Z

362

Apparatus and process for active pulse intensity control of laser beam  

SciTech Connect

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

363

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. 3 figs.

Wilcox, R.B.

1990-12-31T23:59:59.000Z

364

Electron self-injection into an evolving plasma bubble: Quasi-monoenergetic laser-plasma acceleration in the blowout regime  

Science Conference Proceedings (OSTI)

An electron density bubble driven in a rarefied uniform plasma by a slowly evolving laser pulse goes through periods of adiabatically slow expansions and contractions. Bubble expansion causes robust self-injection of initially quiescent plasma electrons, whereas stabilization and contraction terminate self-injection thus limiting injected charge; concomitant phase space rotation reduces the bunch energy spread. In regimes relevant to experiments with hundred terawatt- to petawatt-class lasers, bubble dynamics and, hence, the self-injection process are governed primarily by the driver evolution. Collective transverse fields of the trapped electron bunch reduce the accelerating gradient and slow down phase space rotation. Bubble expansion followed by stabilization and contraction suppresses the low-energy background and creates a collimated quasi-monoenergetic electron bunch long before dephasing. Nonlinear evolution of the laser pulse (spot size oscillations, self-compression, and front steepening) can also cause continuous self-injection, resulting in a large dark current, degrading the electron beam quality.

Kalmykov, S. Y.; Shadwick, B. A.; Umstadter, D. P. [Department of Physics and Astronomy, University of Nebraska - Lincoln, Lincoln, Nebraska 68588-0299 (United States); Beck, A.; Lefebvre, E. [CEA, DAM, DIF, Arpajon F-91297 (France); Yi, S. A.; Khudik, V. N.; Downer, M. C. [Department of Physics, C1500, niversity of Texas at Austin, Austin, Texas 78712 (United States)

2011-05-15T23:59:59.000Z

365

Electron bunch energy and phase feed-forward stabilization system for the Mark V RF-linac free-electron laser  

SciTech Connect

An amplitude and phase compensation system has been developed and tested at the University of Hawai'i for the optimization of the RF drive system to the Mark V free-electron laser. Temporal uniformity of the RF drive is essential to the generation of an electron beam suitable for optimal free-electron laser performance and the operation of an inverse Compton scattering x-ray source. The design of the RF measurement and compensation system is described in detail and the results of RF phase compensation are presented. Performance of the free-electron laser was evaluated by comparing the measured effects of phase compensation with the results of a computer simulation. Finally, preliminary results are presented for the effects of amplitude compensation on the performance of the complete system.

Hadmack, M. R.; Kowalczyk, J. M. D.; Lienert, B. R.; Madey, J. M. J.; Szarmes, E. B. [Department of Physics and Astronomy, University of Hawai'i at Manoa, Honolulu, Hawaii 96822 (United States); Jacobson, B. T. [RadiaBeam Technologies, Santa Monica, California 90404 (United States)

2013-06-15T23:59:59.000Z

366

Electron bunch energy and phase feed-forward stabilization system for the Mark V RF-linac free-electron laser  

E-Print Network (OSTI)

An amplitude and phase compensation system has been developed and tested at the University of Hawai`i for the optimization of the RF drive system to the Mark V Free-Electron Laser. Temporal uniformity of the RF drive is essential to the generation of an electron beam suitable for optimal free-electron laser performance and the operation of an inverse Compton scattering x-ray source. The design of the RF measurement and compensation system is described in detail and the results of RF phase compensation are presented. Performance of the free-electron laser was evaluated by comparing the measured effects of phase compensation with the results of a computer simulation. Finally, preliminary results are presented for the effects of amplitude compensation on the performance of the complete system.

Hadmack, M R; Kowalczyk, J M D; Lienert, B R; Madey, J M J; Szarmes, E B

2013-01-01T23:59:59.000Z

367

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

368

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

SciTech Connect

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

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

2005-09-01T23:59:59.000Z

369

Slow Electrons Generated by Intense High-Frequency Laser Pulses  

Science Conference Proceedings (OSTI)

A very slow electron is shown to emerge when an intense high-frequency laser pulse is applied to a hydrogen negative ion. This counterintuitive effect cannot be accounted for by multiphoton or tunneling ionization mechanisms. We explore the effect and show that in the high-frequency regime the atomic electron is promoted to the continuum via a nonadiabatic transition caused by slow deformation of the dressed potential that follows a variation of the envelope of the laser pulse. This is a general mechanism, and a slow electron peak should always appear in the photoelectron spectrum when an atom is irradiated by a high-frequency pulse of finite length.

Toyota, Koudai; Watanabe, Shinichi [Department of Applied Physics and Chemistry, University of Electro-Communications, 1-5-1, Chofu-ga-oka, Chofu-shi, Tokyo (Japan); Tolstikhin, Oleg I. [Russian Research Center 'Kurchatov Institute', Kurchatov Square 1, Moscow 123182 (Russian Federation); Morishita, Toru [Department of Applied Physics and Chemistry, University of Electro-Communications, 1-5-1, Chofu-ga-oka, Chofu-shi, Tokyo (Japan); PRESTO, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 (Japan)

2009-10-09T23:59:59.000Z

370

Surface science analysis of GaAs photocathodes following sustained electron beam delivery  

DOE Green Energy (OSTI)

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

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

2012-06-01T23:59:59.000Z

371

FREE ELECTRON LASERS FOR THE PRODUCTION OF INFRARED AND MILLIMETER WAVES  

E-Print Network (OSTI)

S.M. Gold, et. al. , in Free Electron Generators of CoherentThe Hughes Low-Voltage Free-Electron Laser Program," inProc. of the 1985 Free Electron Laser Conference, Lake

Sessler, A.M.

2008-01-01T23:59:59.000Z

372

Issues for Bringing Electron Beam Irradiators On-Line  

Science Conference Proceedings (OSTI)

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

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

1999-04-20T23:59:59.000Z

373

Initial commissioning results with the NSCL Electron Beam Ion Trap  

Science Conference Proceedings (OSTI)

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

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

2012-02-15T23:59:59.000Z

374

Status of Jefferson Lab's Load Locked Polarized Electron Beam  

DOE Green Energy (OSTI)

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

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

2002-09-01T23:59:59.000Z

375

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),

376

Development of electron beam pumped KrF Lasers for fusion energy J. D. Sethian, M. Friedman, J. Giuliani, R.H. Lehmberg, M. Myers, S.P. Obenschain,  

E-Print Network (OSTI)

Plant study showed a KrF based system could lead to an economically attractive power plant [3]. In view drive targets; their short wavelength (248 nm), which mitigates the growth of plasma instabilities and transport; KrF kinetics and laser propagation; and pulsed power. The work will be cast in context of the two

377

Semiconductor diode laser having an intracavity spatial phase controller for beam control and switching  

DOE Patents (OSTI)

A high-power broad-area semiconductor laser having a intracavity spatial phase controller is disclosed. The integrated intracavity spatial phase controller is easily formed by patterning an electrical contact metallization layer when fabricating the semiconductor laser. This spatial phase controller changes the normally broad far-field emission beam of such a laser into a single-lobed near-diffraction-limited beam at pulsed output powers of over 400 mW. Two operating modes, a thermal and a gain operating mode, exist for the phase controller, allowing for steering and switching the beam as the modes of operation are switched, and the emission beam may be scanned, for example, over a range of 1.4 degrees or switched by 8 degrees. More than one spatial phase controller may be integrated into the laser structure. 6 figs.

Hohimer, J.P.

1994-06-07T23:59:59.000Z

378

Semiconductor diode laser having an intracavity spatial phase controller for beam control and switching  

DOE Patents (OSTI)

A high-power broad-area semiconductor laser having a intracavity spatial phase controller is disclosed. The integrated intracavity spatial phase controller is easily formed by patterning an electrical contact metallization layer when fabricating the semiconductor laser. This spatial phase controller changes the normally broad far-field emission beam of such a laser into a single-lobed near-diffraction-limited beam at pulsed output powers of over 400 mW. Two operating modes, a thermal and a gain operating mode, exist for the phase controller, allowing for steering and switching the beam as the modes of operation are switched, and the emission beam may be scanned, for example, over a range of 1.4 degrees or switched by 8 degrees. More than one spatial phase controller may be integrated into the laser structure.

Hohimer, John P. (Albuquerque, NM)

1994-01-01T23:59:59.000Z

379

Calibration of the Forward-scattering Spectrometer Probe: Modeling Scattering from a Multimode Laser Beam  

Science Conference Proceedings (OSTI)

Scattering calculations using a more detailed model of the multimode laser beam in the forward-scattering spectrometer probe (FSSP) were carried out by using a recently developed extension to Mie scattering theory. From this model, new ...

Edward A. Hovenac; James A. Lock

1993-08-01T23:59:59.000Z

380

Development of a chemical dosimeter for electron beam food irradiation  

E-Print Network (OSTI)

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

Rivadeneira, Ramiro Geovanny

2003-05-01T23:59:59.000Z

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

Underwater cladding with laser beam and plasma arc welding  

SciTech Connect

Two welding processes, plasma arc (transferred arc) (PTA) and laser beam, were investigated to apply cladding to austenitic stainless steels and Inconel 600. These processes have long been used to apply cladding layers , but the novel feature being reported here is that these cladding layers were applied underwater, with a water pressure equivalent to 24 m (80 ft). Being able to apply the cladding underwater is very important for many applications, including the construction of off-shore oil platforms and the repair of nuclear reactors. In the latter case, being able to weld underwater eliminates the need for draining the reactor and removing the fuel. Welding underwater in reactors presents numerous challenges, but the ability to weld without having to drain the reactor and remove the fuel provides a huge cost savings. Welding underwater in reactors must be done remotely, but because of the radioactive corrosion products and neutron activation of the steels, remote welding would also be required even if the reactor is drained and the fuel removed. In fact, without the shielding of the water, the remote welding required if the reactor is drained might be even more difficult than that required with underwater welds. Furthermore, as shall be shown, the underwater welds that the authors have made were of high quality and exhibit compressive rather than tensile residual stresses.

White, R.A.; Fusaro, R.; Jones, M.G.; Solomon, H.D. [General Electric Corporate Research and Development Center, Schenectady, NY (United States); Milian-Rodriguez, R.R. [GE Nuclear Energy, San Jose, CA (United States)

1997-01-01T23:59:59.000Z

382

Design Considerations for Plasma Accelerators Driven by Lasers or Particle Beams  

SciTech Connect

Plasma accelerators may be driven by the ponderomotive force of an intense laser or the space-charge force of a charged particle beam. The implications for accelerator design and the different physical mechanisms of laser-driven and beam-driven plasma acceleration are discussed. Driver propagation is examined, as well as the effects of the excited plasma wave phase velocity. The driver coupling to subsequent plasma accelerator stages for high-energy physics applications is addressed.

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

2010-06-01T23:59:59.000Z

383

Fiber Optic Picosecond Laser Pulse Transmission Line for Hydrogen Ion Beam Profile Measurement  

Science Conference Proceedings (OSTI)

We present a fiber optic laser pulse transmission line for non-intrusive longitudinal profile measurement of the hydrogen ion (H-) beam at the front-end of the Spallation Neutron Source (SNS) accelerator. The 80.5 MHz, 2.5 ps, multi-killowatt optical pulses are delivered to the accelerator beam line through a large mode area polarization maintaining optical fiber to ensure a high measurement stability. The transmission efficiency, output laser beam quality, pulse jitter and pulse width broadening over a 100-ft fiber line are experimentally investigated. A successful measurement of the H- beam microbunch (~130 ps) profile is obtained. Our experiment is the first demonstration of particle beam profile diagnostics using fiber optic laser pulse transmission line.

Liu, Yun [ORNL; Huang, Chunning [ORNL; Aleksandrov, Alexander V [ORNL

2013-01-01T23:59:59.000Z

384

Supporting soil remediation at Fernald by electron beam methods  

SciTech Connect

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

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

1994-02-01T23:59:59.000Z

385

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

SciTech Connect

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

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

2004-08-03T23:59:59.000Z

386

Measurement of ion beam profiles in a superconducting linac with a laser wire  

Science Conference Proceedings (OSTI)

A laser wire ion beam profile monitor system has been developed at the Spallation Neutron Source accelerator complex. The laser wire system uses a single laser source to measure the horizontal and vertical profiles of a pulsed hydrogen ion (H{sup -}) beam along a 230 m long superconducting linac, which accelerates H{sup -} from 200 MeV to 1 GeV. In this paper, we describe the laser optics requirement for the system, the performance of the profile measurement, and the effects of laser parameters on the measurement reliability. The result provides a practical guideline for the development of a large-scale, operational, laser-based diagnostics in accelerator facilities.

Liu Yun; Long, Cary; Peters, Charles; Aleksandrov, Alexander

2010-12-10T23:59:59.000Z

387

Calibrating laser test-beams for cosmic-ray observatories  

E-Print Network (OSTI)

Pulsed UV lasers can provide useful "testbeams" for observatories that use optical detectors, especially fluorescence detectors, to measure high energy cosmic-rays. The light observed by the detector is proportional to the energy of the laser pulse. Since the absolute laser energy can be measured locally, a well-calibrated laser offers a practical way to test the photometric calibration of the cosmic-ray detector including atmospheric corrections. This poster will describe a robotic system for laser polarization and energy calibration. Laboratory measurements of laser energies and polarizations by energy probes from different manufactures will be presented

Wiencke, Lawrence; Compton, John; Monasor, Maria; Pilger, David; Rosado, Jaime

2011-01-01T23:59:59.000Z

388

Nondestructive evaluation of electron-beam braze joins  

Science Conference Proceedings (OSTI)

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

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

1981-08-18T23:59:59.000Z

389

SIMULATION STUDY OF THREE-DIMENSIONAL LASER COOLING SCHEMES FOR FAST STORED BEAMS  

SciTech Connect

Molecular dynamics (MD) approach is employed to study laser cooling of fast circulating beams in a storage ring. The authors compare several three-dimensional (3D) cooling methods, examining achievable minimum beam temperature. In particular, the stress is put upon the three coupling schemes, i.e. the dispersion-coupling scheme, the coupling-cavity scheme, and the tapered cooling scheme. The authors show that beam temperatures much lower than the currently achievable level could be reached with these schemes.

KIHARA,T.; OKAMOTO,H.; IWASHITA,Y.; OIDE,K.; LAMANNA,G.; WEI,J.

1998-06-22T23:59:59.000Z

390

Semiconductor diode laser having an intracavity spatial phase controller for beam control and switching  

DOE Patents (OSTI)

A high-power broad-area semiconductor laser having a intracavity spatial phase controller is disclosed. The integrated intracavity spatial phase controller is easily formed by patterning an electrical contact metallization layer when fabricating the semiconductor laser. This spatial phase controller changes the normally broad far-field emission bean, of such a laser into a single-lobed near-diffraction-limited beam at pulsed output powers of over 400 mW. Two operating modes, a thermal and a gain operating mode, exist for the phase controller, allowing for steering and switching the beam as the modes of operation are switched, and the emission beam may be scanned, for example, over a range of 1.4 degrees or switched by 8 degrees. More than one spatial phase controller may be integrated into the laser structure.

Hohimer, J.P.

1992-12-31T23:59:59.000Z

391

Parametric lower-hybrid instability driven by modulated electron beam injection  

SciTech Connect

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

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

1978-08-01T23:59:59.000Z

392

THE SYSTEM OF POWER SUPPLIES, CONTROL AND MODULATION OF ELECTRON GUN FOR FREE ELECTRON LASER  

E-Print Network (OSTI)

. The output of power inverter is connected to input coil of isolated power transformer (300kV). Timer Electric power for part 2 goes from power inverter through isolated power transformer (isolation voltageTHE SYSTEM OF POWER SUPPLIES, CONTROL AND MODULATION OF ELECTRON GUN FOR FREE ELECTRON LASER E

Kozak, Victor R.

393

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

Science Conference Proceedings (OSTI)

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

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

2011-10-01T23:59:59.000Z

394

On the control of filamentation of intense laser beams propagating in underdense plasma  

SciTech Connect

In indirect drive ICF ignition designs, the laser energy is delivered into the hohlraum through the laser entrance holes (LEH), which are sized as small as practicable to minimize X-ray radiation losses. On the other hand, deleterious laser plasma processes, such as filamentation and stimulated back-scatter, typically increase with laser intensity. Ideally, therefore, the laser spot shape should be a close fit to the LEH, with uniform (envelope) intensity in the spot and minimal energy at larger radii spilling onto the LEH material. This keeps the laser intensity as low as possible consistent with the area of the LEH aperture and the power requirements of the design. This can be achieved (at least for apertures significantly larger than the laser's aberrated focal spot) by the use of custom-designed phase plates. However, outfitting the 192 beam (National Ignition facility) NIF laser with multiple sets of phase plates optimized for a variety of different LEH aperture sizes is an expensive proposition. It is thus important to assess the impact on laser-plasma interaction processes of using phase plates with a smaller than optimum focal spot (or even no phase plates at all!) and then de-focusing the beam to expand it to fill the LEH and lower its intensity. We find significant effects from the lack of uniformity of the laser envelope out of the focal plane, from changes in the characteristic sizes of the laser speckle, and on the efficacy of additional polarization and/or SSD beam smoothing. We quantify these effects with analytic estimates and simulations using our laser plasma interaction code pF3D.

Williams, E A

2005-10-21T23:59:59.000Z

395

FREE ELECTRON LASER FOR SIBERIAN CENTRE FOR PHOTOCHEMICAL RESEARCH: THE CONTROL SYSTEM FOR THE  

E-Print Network (OSTI)

FREE ELECTRON LASER FOR SIBERIAN CENTRE FOR PHOTOCHEMICAL RESEARCH: THE CONTROL SYSTEM of the Siberian Branch of RAS. Abstract. A control system for the magnetic system of the free electron laser (FEL

Kozak, Victor R.

396

High Power Microwave Switch Employing Electron Beam Triggering  

Science Conference Proceedings (OSTI)

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

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

2010-11-04T23:59:59.000Z

397

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

398

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

SciTech Connect

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

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

2010-11-15T23:59:59.000Z

399

Measurements of fast electron scaling generated by petawatt laser systems  

Science Conference Proceedings (OSTI)

Fast electron energy spectra have been measured for a range of intensities between 10{sup 18} and 10{sup 21} W cm{sup -2} and for different target materials using electron spectrometers. Several experimental campaigns were conducted on petawatt laser facilities at the Rutherford Appleton Laboratory and Osaka University, where the pulse duration was varied from 0.5 to 5 ps relevant to upcoming fast ignition integral experiments. The incident angle was also changed from normal incidence to 40 deg. in p-polarized. The results confirm a reduction from the ponderomotive potential energy on fast electrons at the higher intensities under the wide range of different irradiation conditions.

Tanimoto, Tsuyoshi; Habara, H.; Kodama, R.; Nakatsutsumi, M.; Tanaka, Kazuo A. [Graduate School of Engineering and Institute of Laser Engineering, Osaka University, 2-1 Yamada-oka, Suita, Osaka 565-0871 (Japan); Lancaster, K. L.; Green, J. S. [STFC Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX (United Kingdom); Scott, R. H. H.; Sherlock, M.; Norreys, Peter A. [STFC Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX (United Kingdom); Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ (United Kingdom); Evans, R. G.; Haines, M. G. [Department of Physics, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BZ (United Kingdom); Kar, S.; Zepf, M. [Centre for Plasma Physics, School of Mathematics and Physics, Queens University Belfast, University Road, Belfast BT7 1NN (United Kingdom); King, J.; Ma, T.; Wei, M. S.; Yabuuchi, T.; Beg, F. N. [Department of Mechanical and Aerospace Engineering, University of California-San Diego, 9500 Gillman Drive 0411, La Jolla, California 92093-0411 (United States); Key, M. H. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)] (and others)

2009-06-15T23:59:59.000Z

400

Transmission of electron through monolayer graphene laser barrier  

Science Conference Proceedings (OSTI)

The present theoretical model deals with the transmission property of the Dirac fermions in the Floquet sidebands for the laser radiated graphene nanostructure. The laser assisted structure behaves as a tunneling barrier that leads to asymmetric transmission around the normal to the interface and is capable to confine the massless Dirac particles in a monolayer graphene strip. The absence of the Klein tunneling and the presence of a large number of controlling parameters would make the time dependent vector potential barrier superior over the electrostatic and magnetic barriers towards the opto-electronic device fabrication.

Sinha, C. [Department of Theoretical Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032 (India); Biswas, R. [Department of Physics, P. K. College, Contai, Purba Medinipur, West Bengal 721401 (India)

2012-04-30T23:59:59.000Z

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.


401

CP-violation reach of an electron capture neutrino beam  

E-Print Network (OSTI)

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

Orme, Christopher

2009-01-01T23:59:59.000Z

402

CP-violation reach of an electron capture neutrino beam  

E-Print Network (OSTI)

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

Christopher Orme

2009-12-14T23:59:59.000Z

403

Efficient laser absorption and enhanced electron yield in the laser-target interaction by using a cone-nanolayer target  

Science Conference Proceedings (OSTI)

A cone-nanolayer target that combines the advantages of the conical and layered geometries for electron acceleration in laser-target interaction is proposed. Two-dimensional particle-in-cell (PIC) simulations show that the cone-nanolayer target can enhance laser absorption and electron yield. With suitable choice of the laser and target parameters, the cone-nanolayer target can be a controllable source of hot electrons at desired energy ranges.

Cao Lihua; Cai Hongbao [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Chen Mo; Wu Sizhong [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Zhao Zongqing; Gu Yuqiu [Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China); Yu Wei [Shanghai Institute of Optics and Fine Mechanics, Shanghai 201800 (China); Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (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); He, X. T. [Institute of Applied Physics and Computational Mathematics, Beijing 100088 (China); Center for Applied Physics and Technology, Peking University, Beijing 100871 (China); Institute for Fusion Theory and Simulation, Zhejiang University, Hangzhou 310027 (China)

2011-05-15T23:59:59.000Z

404

Electron bunch injection at an angle into a laser wakefield  

E-Print Network (OSTI)

External injection of electron bunches longer than the plasma wavelength in a laser wakefield accelerator can lead to the generation of femtosecond ultrarelativistic bunches with a couple of percent energy spread. Extensive study has been done on external electron bunch (e.g. one generated by a photo-cathode rf linac) injection in a laser wakefield for different configurations. In this paper we investigate a new way of external injection where the electron bunch is injected at a small angle into the wakefield. This way one can avoid the ponderomotive scattering as well as the vacuum-plasma transition region, which tend to destroy the injected bunch. In our simulations, the effect of the laser pulse dynamics is also taken into account. It is shown that injection at an angle can provide compressed and accelerated electron bunches with less than 2% energy spread. Another advantage of this scheme is that it has less stringent requirements in terms of the size of the injected bunch and there is the potential to tr...

Luttikhof, M J H; Van Goor, F A; Boller, K -J

2008-01-01T23:59:59.000Z

405

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

E-Print Network (OSTI)

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

406

Laser photoionization of H/sup 0/ beams for charge-changing injection  

DOE Green Energy (OSTI)

The two-step charge-changing injection used in the Los Alamos Proton Storage Ring (PSR) requires stripping of H/sup -/ to H/sup 0/ by high magnetic fields and subsequent stripping of H/sup 0/ to H/sup +/ by a carbon foil. We consider single- and multiphoton laser ionization as alternatives to using a fragile foil. The multiphoton case is of possible interest for selection of practical lasers, which tend to have increased power output at higher wavelengths. The formulas derived express the necessary laser powers for ionization of monoenergetic H/sup 0/ beams; they also hold for beams of particles other than atomic hydrogen. The numerical examples given are for the 800-MeV PSR beam with momentum spread taken into account. Additionally, we discuss selective stripping as an implication of the inherent energy selectivity of the photoionization process.

Blind, B.; Jason, A.J.

1983-01-01T23:59:59.000Z

407

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

Science Conference Proceedings (OSTI)

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

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

2010-12-27T23:59:59.000Z

408

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

Science Conference Proceedings (OSTI)

Several recent reports have identified the scientific requirements for a future soft x-ray light source, and a high-repetition-rate free-electron laser (FEL) facility that is responsive to these requirements is now on the horizon. R&D in some critical areas is needed, however, to demonstrate technical performance, thus reducing technical risks and construction costs. Such a facility most likely will be based on a CW superconducting linear accelerator with beam supplied by a high-brightness, high-repetition-rate photocathode electron gun operating in CW mode, and on an array of FELs to which the accelerated beam is distributed, each operating at high repetition rate and with even pulse spacing. Dependent on experimental requirements, the individual FELs can be configured for either self-amplified spontaneous emission (SASE), seeded, or oscillator mode of operation, including the use of high-gain harmonic generation (HGHG), echo-enhanced harmonic generation (EEHG), harmonic cascade, or other configurations. In this White Paper we identify the overall accelerator R&D needs, and highlight the most important pre-construction R&D tasks required to value-engineer the design configuration and deliverables for such a facility. In Section 1.4 we identify the comprehensive R&D ultimately needed. We identify below the highest-priority requirements for understanding machine performance and reduce risk and costs at this pre-conceptual design stage. Details of implementing the required tasks will be the subject of future evaluation. Our highest-priority R&D program is the injector, which must be capable of delivering a beam with bunches up to a nanocoulomb at MHz repetition rate and with normalized emittance {le} 1 mm {center_dot} mrad. This will require integrated accelerating structure, cathode, and laser systems development. Cathode materials will impact the choice of laser technology in wavelength and energy per pulse, as well as vacuum requirements in the accelerating structure. Demonstration experiments in advanced seeding techniques, such as EEHG, and other optical manipulations to enhance the FEL process are required to reduce technical risk in producing temporally coherent and ultrashort x-ray output using optical seed lasers. Success of EEHG in particular would result in reduced development and cost of laser systems and accelerator hardware for seeded FELs. With a 1.5-2.5 GeV linac, FELs could operate in the VUV-soft x-ray range, where the actual beam energy will be determined by undulator technology; for example, to use the lower energy would require the use of advanced designs for which undulator R&D is needed. Significant reductions in both unit costs and accelerator costs resulting from the lower electron beam energy required to achieve lasing at a particular wavelength could be obtained with undulator development. Characterization of the wakefields of the vacuum chambers in narrow-gap undulators will be needed to minimize risk in ability to deliver close to transform limited pulses. CW superconducting RF technology for an FEL facility with short bunches at MHz rate and up to mA average current will require selection of design choices in cavity frequency and geometry, higher order mode suppression and power dissipation, RF power supply and distribution, accelerating gradient, and cryogenics systems. R&D is needed to define a cost and performance optimum. Developments in laser technology are proceeding at rapid pace, and progress in high-power lasers, harmonic generation, and tunable sources will need to be tracked.

Corlett, John; Attwood, David; Byrd, John; Denes, Peter; Falcone, Roger; Heimann, Phil; Leemans, Wim; Padmore, Howard; Prestemon, Soren; Sannibale, Fernando; Schlueter, Ross; Schroeder, Carl; Staples, John; Venturini, Marco; Warwick, Tony; Wells, Russell; Wilcox, Russell; Zholent, Alexander; Adolphsen, Chris; Arthur, John; Bergmann, Uwe; Cai, Yunhai; Colby, Eric; Dowell, David; Emma, Paul; Fox, John; Frisch, Josef; Galayda, John; Hettel, Robert; Huang, Zhirong; Phinney, Nan; Rabedeau, Tom; Raubenheimer, Tor; Reis, David; Schmerge, John; Sthr, Joachim; Stupakov, Gennady; White, Bill; Xiang, Dao

2009-06-08T23:59:59.000Z

409

The First Angstrom X-Ray Free-Electron Laser  

SciTech Connect

The Linac Coherent Light Source produced its first x-ray laser beam on 10 April 2009. Today it is routinely producing x-ray pulses with energy >2 mJ across the operating range from 820-8,200 eV. The facility has begun operating for atomic/molecular/optical science experiments. Performance of the facility in its first user run (1 October - 21 December) and current machine development activities will be presented. Early results from the preparations for the start of the second user run is also reported.

Galayda, John; /SLAC

2012-08-24T23:59:59.000Z

410

Simulation of Hollow Electron Beam Collimation in the Fermilab Tevatron Collider  

Science Conference Proceedings (OSTI)

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

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

2012-05-01T23:59:59.000Z

411

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

E-Print Network (OSTI)

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

Akgun, Ugur

412

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

Science Conference Proceedings (OSTI)

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

Jochen Grebing; JRgen FaBender; Artur Erbe

2012-09-01T23:59:59.000Z

413

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

E-Print Network (OSTI)

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

414

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

415

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 fluids 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. 8 figs.

Kare, J.T.

1990-12-31T23:59:59.000Z

416

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 fluids 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. 8 figs.

Kare, J.T.

1990-01-01T23:59:59.000Z

417

Laser power beaming to extend lives of GSO NiCd satellites  

DOE Green Energy (OSTI)

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

418

Fifth-Generation Free-Electron Laser Light Sources  

SciTech Connect

During the past few years, the Linac Coherent Light Source (LCLS) and the Free-Electron Laser in Hamburg (FLASH) have demonstrated the outstanding capability of free-electron lasers (FELs) as sources of coherent radiation in the soft and hard x-ray region. The high intensity, tens of GW, short pulses (few to less than 100 femtoseconds, and the unique transverse coherence properties are opening a new window to study the structure and dynamics of atomic and molecular systems. The LCLS, FLASH, and the other FELs now under construction are only the beginning of the development of these light sources. The next generations will reach new levels of performance: terawatt, atto-second, ultra-small line-width, high repetition rate, full longitudinal and transverse coherence. These future developments and the R&D needed to successfully build and operate the next generation of FEL light sources will be discussed.

Pellegrini, Claudio [UCLA

2011-03-02T23:59:59.000Z

419

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

420

PHYSICS WITH AND PHYSICS OF COLLIDING ELECTRON BEAMS  

E-Print Network (OSTI)

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

Pellegrini, Claudio

2008-01-01T23:59:59.000Z

Note: This page contains sample records for the topic "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

Ultrarelativistic laser systems based on coherent beam combining  

Science Conference Proceedings (OSTI)

Conceptual design for femtosecond laser system of exawatt class, based on multi-channel amplifier and coherent field combining of petawatt amplifier channels with phase-frequency controlled radiation by optical clock are discussed. The scheme of start petawatt level few-cycle laser system with stable phase-frequency parameters determinated by the accuracy of the optical standard based on parametric amplification in big-size LBO crystals pumped by picosecond pulses is analyzed.

Bagayev, S. N.; Trunov, V. I.; Pestryakov, E. V.; Frolov, S. A.; Leschenko, V. E.; Kirpichnikov, A. V.; Kokh, A. E.; Petrov, V. V.; Vasiliev, V. A. [Institute of Laser Physics SB RAS, Ac. Lavrentyev's prosp., 13/3, Novosibirsk (Russian Federation); Institute of Geology and Mineralogy SB RAS, Ac. Koptug's prosp., 3, Novosibirsk (Russian Federation); Institute of Laser Physics SB RAS, Ac. Lavrentyev's prosp., 13/3, Novosibirsk (Russian Federation)

2012-07-11T23:59:59.000Z

422

Velocity distribution measurements in atomic beams generated using laser induced back-ablation  

E-Print Network (OSTI)

We present measurements of the velocity distribution of calcium atoms in an atomic beam generated using a dual-stage laser back-ablation apparatus. Distributions are measured using a velocity selective Doppler time-of-flight technique. They are Boltzmann-like with rms velocities corresponding to temperatures above the melting point for calcium. Contrary to a recent report in the literature, this method does not generate a sub-thermal atomic beam.

Denning, A; Lee, S; Ammonson, M; Bergeson, S D

2008-01-01T23:59:59.000Z

423

Applications of laser produced ion beams to nuclear analysis of materials  

Science Conference Proceedings (OSTI)

Laser produced ion beams have unique characteristics which are ultra-short pulse, very low emittance, and variety of nuclear species. These characteristics could be used for analyzing various materials like low Z ion doped heavy metals or ceramics. Energies of laser produced ion beam extend from 0.1MeV to 100MeV. Therefore, various nuclear processes can be induced in the interactions of ion beams with samples. The ion beam driven nuclear analysis has been developed for many years by using various electrostatic accelerators. To explore the applicability of laser ion beam to the analysis of the Li ion battery, a proton beam with the diameter of {approx} 1.0 {mu}m at Takasaki Ion Acceleration for Advanced Radiation Application (TIARA), JAEA was used. For the analysis, the PIGE (Particle-Induced Gamma Ray Emission) is used. The proton beam scans over Li battery electrode samples to diagnose Li density in the LiNi{sub 0.85}Co{sub 0.15}O{sub 2} anode. As the results, PIGE images for Li area density distributions are obtained with the spatial resolution of better than 1.5{mu}m FWHM. By the Li PIGE images, the depth dependence of de-intercalation levels of Li in the anode is obtained. By the POP experiments at TIARA, it is clarified that laser produced ion beam is appropriate for the Li ion battery analysis. 41.85.Lc, 41.75.Jv, 42.62.cf.

Mima, K.; Azuma, H.; Fujita, K.; Yamazaki, A.; Okuda, C.; Ukyo, Y.; Kato, Y.; Arrabal, R. Gonzalez; Soldo, F.; Perlado, J. M.; Nishimura, H.; Nakai, S. [Graduate School for the Creation of New Photonics Industries, Shizuoka (Japan) and Institute de Fusion Nuclear, Universidad Politecnica de Madrid, Madrid (Spain) and Institute of Laser Engineering, Osaka University, Osaka (Japan); Toyota Central R and D Labs., Inc., Aichi (Japan); Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA), Gunnma (Japan); Toyota Central R and D Labs., Inc., Aichi (Japan)

2012-07-11T23:59:59.000Z

424

Nonintrusive Emittance Measurement of 1GeV H- Beam with a Laser  

SciTech Connect

A laser wire based transverse phase space measurement system has been developed at the Spallation Neutron Source (SNS). The system allows a nonintrusive measurement of 1GeV hydrogen ion (H-) beam at the high energy beam transport (HEBT). This paper describes the design, installation, and measurement performance of the system. Major technical challenges in the implementation and commissioning of the nonintrusive phase space diagnostics at high brightness particle accelerator facilities are discussed.

Liu, Yun [ORNL; Aleksandrov, Alexander V [ORNL; Long, Cary D [ORNL; Menshov, Alexander A [ORNL; Pogge, James R [ORNL; Webster, Anthony W [ORNL; Zhukov, Alexander P [ORNL

2012-01-01T23:59:59.000Z

425

High-order-harmonic generation in gas with a flat-top laser beam  

Science Conference Proceedings (OSTI)

We present experimental and numerical results on high-order-harmonic generation with a flat-top laser beam. We show that a simple binary tunable phase plate, made of two concentric glass plates, can produce a flat-top profile at the focus of a Gaussian infrared beam. Both experiments and numerical calculations show that there is a scaling law between the harmonic generation efficiency and the increase of the generation volume.

Boutu, W.; Auguste, T.; Binazon, L.; Gobert, O.; Carre, B. [Service des Photons, Atomes et Molecules, CEA-Saclay, FR-91191 Gif-sur-Yvette Cedex (France); Boyko, O.; Valentin, C. [Laboratoire d'Optique Appliquee, UMR 7639 ENSTA/CNRS/Ecole Polytechnique, FR-91761 Palaiseau (France); Sola, I.; Constant, E.; Mevel, E. [Universite de Bordeaux, CEA, CNRS UMR 5107, CELIA (Centre Lasers Intenses et Applications), FR-33400 Talence (France); Balcou, Ph. [Laboratoire d'Optique Appliquee, UMR 7639 ENSTA/CNRS/Ecole Polytechnique, FR-91761 Palaiseau (France); Universite de Bordeaux, CEA, CNRS UMR 5107, CELIA (Centre Lasers Intenses et Applications), FR-33400 Talence (France); Merdji, H. [Service des Photons, Atomes et Molecules, CEA-Saclay, FR-91191 Gif-sur-Yvette Cedex (France); PULSE Institute for Ultrafast Energy Science, Stanford Linear Accelerator Center, Stanford University, 2575 Sand Hill Road, Menlo Park, California 94025 (United States)

2011-12-15T23:59:59.000Z

426

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

427

Desktop megawatt superradiant free-electron laser at terahertz frequencies  

SciTech Connect

I present a theoretical and simulation study of a desktop, megawatt (MW), terahertz (THz) superradiance free-electron laser (FEL) driven by a THz-pulse-train photoinjector. With nominal electron parameters from a THz-pulse-train photoinjector, this superradiant FEL is capable of generating more than 5 MW power at THz frequencies from a half-meter, single-pass undulator. Tapering the undulator to a length of 1.5 m can further increase the FEL output power to nearly 15 MW.

Huang, Y.-C. [Department of Electrical Engineering, National Tsinghua University, Hsinchu 30013, Taiwan (China)

2010-06-07T23:59:59.000Z

428

Bending of metal-filled carbon nanotube under electron beam irradiation  

Science Conference Proceedings (OSTI)

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

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

2012-03-15T23:59:59.000Z

429

Dye laser amplifier including an improved window configuration for its dye beam  

DOE Patents (OSTI)

A dye laser amplifier in which a continuously replenished supply of dye is excited with a first light beam in order to amplify the intensity of a second different light beam passing therethrough is disclosed herein. This amplifier includes a cell though which a continuous stream of the dye is caused to pass, and means for directing the first beam into the cell while the second beam is directed into and through the same cell. There is also disclosed herein a specific improvement to this amplifier which resides in the use of a pair of particularly configured windows through which the second beam passes along fixed paths as the second beam enters and exits the dye cell. Each of these windows has a relatively thick main section which is substantially larger in dimensions transverse to its beam path than the cross section of the second beam itself, whereby to add structural integrity to the overall window. At the same time, the latter includes a second section which is disposed entirely within the confines of the main section and through which the second beam is intended to pass in its entirety. This second section is made substantially thinner than the main section in order to reduce optical distortion as the second beam passes therethrough.

O' Neil, Richard W. (Pleasanton, CA); Davin, James M. (Livermore, CA)

1992-01-01T23:59:59.000Z

430

Dye laser amplifier including an improved window configuration for its dye beam  

DOE Patents (OSTI)

A dye laser amplifier in which a continuously replenished supply of dye is excited with a first light beam in order to amplify the intensity of a second different light beam passing therethrough is disclosed herein. This amplifier includes a cell though which a continuous stream of the dye is caused to pass, and means for directing the first beam into the cell while the second beam is directed into and through the same cell. There is also disclosed herein a specific improvement to this amplifier which resides in the use of a pair of particularly configured windows through which the second beam passes along fixed paths as the second beam enters and exits the dye cell. Each of these windows has a relatively thick main section which is substantially larger in dimensions transverse to its beam path than the cross section of the second beam itself, whereby to add structural integrity to the overall window. At the same time, the latter includes a second section which is disposed entirely within the confines of the main section and through which the second beam is intended to pass in its entirety. This second section is made substantially thinner than the main section in order to reduce optical distortion as the second beam passes therethrough. 4 figs.

O' Neil, R.W.; Davin, J.M.

1992-12-01T23:59:59.000Z

431

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

SciTech Connect

The optimal performance of the two electron lenses that are being implemented for high intensity polarized proton operation of RHIC requires excellent collinearity of the {approx}0.3 mm RMS wide <